Merge tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linuxgrafted

Pull io_uring fixes from Jens Axboe:

 - Fix a task_work add use-after-free with SQPOLL.

   The sqpoll thread could pop and complete the last request while
   io_req_normal_work_add() was still looking at them after the mpscq
   push.

   Use the same approach as DEFER_TASKRUN to protect from that, holding
   an RCU read lock across the add, and have exit wait for an RCU grace
   period for SQPOLL rings as well.

 - CQE32 ring fixes: correct the free entry check for 32b CQEs, zero the
   big_cqe for aux CQEs, and only post the dummy skip CQE on CQE_MIXED
   rings

 - Mark the source filter table as COW when cloning bpf filters, so
   registering another filter on the source doesn't modify the shared
   table in place

 - Initialize the task context before running the BPF loop

 - Requeue zcrx multishot receives stopped by a local resource

 - End a TX_TIMESTAMP multishot cmd when the CQ is full (lollipopkit)

* tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
  io_uring: fix task_work add use-after-free with SQPOLL
  io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full
  io_uring/zcrx: requeue multishot receives stopped by a local resource
  io_uring: initialize task context before running the BPF loop
  io_uring: zero big_cqe for aux CQEs on CQE32 rings
  io_uring: fix free entry check for 32b CQEs on CQE32 rings
  io_uring: only post the dummy skip CQE on CQE_MIXED rings
  io_uring/bpf_filter: mark source as COW when cloning filters

128 files changed, 71290 insertions, 0 deletions

diff --git a/sound/usb/6fire/Makefile b/sound/usb/6fire/Makefile
new file mode 100644
index 000000000..587f25c64
--- /dev/null
+++ b/sound/usb/6fire/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+snd-usb-6fire-y += chip.o comm.o midi.o control.o firmware.o pcm.o
+obj-$(CONFIG_SND_USB_6FIRE) += snd-usb-6fire.o
+
diff --git a/sound/usb/6fire/chip.c b/sound/usb/6fire/chip.c
new file mode 100644
index 000000000..6cf410a92
--- /dev/null
+++ b/sound/usb/6fire/chip.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Main routines and module definitions.
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#include "chip.h"
+#include "firmware.h"
+#include "pcm.h"
+#include "control.h"
+#include "comm.h"
+#include "midi.h"
+
+#include <linux/moduleparam.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/gfp.h>
+#include <sound/initval.h>
+
+MODULE_AUTHOR("Torsten Schenk <torsten.schenk@zoho.com>");
+MODULE_DESCRIPTION("TerraTec DMX 6Fire USB audio driver");
+MODULE_LICENSE("GPL v2");
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-max */
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* Id for card */
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP; /* Enable card */
+static struct sfire_chip *chips[SNDRV_CARDS] = SNDRV_DEFAULT_PTR;
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "Index value for the 6fire sound device");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string for the 6fire sound device.");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "Enable the 6fire sound device.");
+
+static DEFINE_MUTEX(register_mutex);
+
+static void usb6fire_chip_abort(struct sfire_chip *chip)
+{
+	if (chip->pcm)
+		usb6fire_pcm_abort(chip);
+	if (chip->midi)
+		usb6fire_midi_abort(chip);
+	if (chip->comm)
+		usb6fire_comm_abort(chip);
+	if (chip->control)
+		usb6fire_control_abort(chip);
+}
+
+static void usb6fire_card_free(struct snd_card *card)
+{
+	struct sfire_chip *chip = card->private_data;
+
+	if (chip->pcm)
+		usb6fire_pcm_destroy(chip);
+	if (chip->midi)
+		usb6fire_midi_destroy(chip);
+	if (chip->comm)
+		usb6fire_comm_destroy(chip);
+	if (chip->control)
+		usb6fire_control_destroy(chip);
+}
+
+static int usb6fire_chip_probe(struct usb_interface *intf,
+			       const struct usb_device_id *usb_id)
+{
+	int ret;
+	int i;
+	struct sfire_chip *chip = NULL;
+	struct usb_device *device = interface_to_usbdev(intf);
+	int regidx = -1; /* index in module parameter array */
+	struct snd_card *card = NULL;
+
+	/* look if we already serve this card and return if so */
+	guard(mutex)(&register_mutex);
+	for (i = 0; i < SNDRV_CARDS; i++) {
+		if (chips[i] && chips[i]->dev == device) {
+			chips[i]->intf_count++;
+			usb_set_intfdata(intf, chips[i]);
+			return 0;
+		} else if (!chips[i] && regidx < 0)
+			regidx = i;
+	}
+	if (regidx < 0) {
+		dev_err(&intf->dev, "too many cards registered.\n");
+		return -ENODEV;
+	}
+
+	/* check, if firmware is present on device, upload it if not */
+	ret = usb6fire_fw_init(intf);
+	if (ret < 0)
+		return ret;
+	else if (ret == FW_NOT_READY) /* firmware update performed */
+		return 0;
+
+	/* if we are here, card can be registered in alsa. */
+	if (usb_set_interface(device, 0, 0) != 0) {
+		dev_err(&intf->dev, "can't set first interface.\n");
+		return -EIO;
+	}
+	ret = snd_card_new(&intf->dev, index[regidx], id[regidx],
+			   THIS_MODULE, sizeof(struct sfire_chip), &card);
+	if (ret < 0) {
+		dev_err(&intf->dev, "cannot create alsa card.\n");
+		return ret;
+	}
+	strscpy(card->driver, "6FireUSB");
+	strscpy(card->shortname, "TerraTec DMX6FireUSB");
+	sprintf(card->longname, "%s at %d:%d", card->shortname,
+			device->bus->busnum, device->devnum);
+
+	chip = card->private_data;
+	chip->dev = device;
+	chip->regidx = regidx;
+	chip->intf_count = 1;
+	chip->card = card;
+	card->private_free = usb6fire_card_free;
+
+	ret = usb6fire_comm_init(chip);
+	if (ret < 0)
+		goto destroy_chip;
+
+	ret = usb6fire_midi_init(chip);
+	if (ret < 0)
+		goto destroy_chip;
+
+	ret = usb6fire_pcm_init(chip);
+	if (ret < 0)
+		goto destroy_chip;
+
+	ret = usb6fire_control_init(chip);
+	if (ret < 0)
+		goto destroy_chip;
+
+	ret = snd_card_register(card);
+	if (ret < 0) {
+		dev_err(&intf->dev, "cannot register card.");
+		goto destroy_chip;
+	}
+
+	usb_set_intfdata(intf, chip);
+	chips[regidx] = chip;
+
+	return 0;
+
+destroy_chip:
+	chip->shutdown = true;
+	if (card)
+		snd_card_disconnect(card);
+	usb6fire_chip_abort(chip);
+	snd_card_free(card);
+	return ret;
+}
+
+static void usb6fire_chip_disconnect(struct usb_interface *intf)
+{
+	struct sfire_chip *chip;
+	struct snd_card *card;
+
+	guard(mutex)(&register_mutex);
+	chip = usb_get_intfdata(intf);
+	/* if !chip, fw upload has been performed */
+	if (!chip)
+		return;
+
+	chip->intf_count--;
+	if (chip->intf_count)
+		return;
+
+	chips[chip->regidx] = NULL;
+
+	/*
+	 * Save card pointer before teardown.
+	 * snd_card_free_when_closed() may free card (and
+	 * the embedded chip) immediately, so it must be
+	 * called last and chip must not be accessed after.
+	 */
+	card = chip->card;
+	chip->shutdown = true;
+	if (card)
+		snd_card_disconnect(card);
+	usb6fire_chip_abort(chip);
+	if (card)
+		snd_card_free_when_closed(card);
+}
+
+static const struct usb_device_id device_table[] = {
+	{
+		.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor = 0x0ccd,
+		.idProduct = 0x0080
+	},
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, device_table);
+
+static struct usb_driver usb_driver = {
+	.name = "snd-usb-6fire",
+	.probe = usb6fire_chip_probe,
+	.disconnect = usb6fire_chip_disconnect,
+	.id_table = device_table,
+};
+
+module_usb_driver(usb_driver);
diff --git a/sound/usb/6fire/chip.h b/sound/usb/6fire/chip.h
new file mode 100644
index 000000000..8124259b4
--- /dev/null
+++ b/sound/usb/6fire/chip.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+#ifndef USB6FIRE_CHIP_H
+#define USB6FIRE_CHIP_H
+
+#include "common.h"
+
+struct sfire_chip {
+	struct usb_device *dev;
+	struct snd_card *card;
+	int intf_count; /* number of registered interfaces */
+	int regidx; /* index in module parameter arrays */
+	bool shutdown;
+
+	struct midi_runtime *midi;
+	struct pcm_runtime *pcm;
+	struct control_runtime *control;
+	struct comm_runtime *comm;
+};
+#endif /* USB6FIRE_CHIP_H */
+
diff --git a/sound/usb/6fire/comm.c b/sound/usb/6fire/comm.c
new file mode 100644
index 000000000..510d31082
--- /dev/null
+++ b/sound/usb/6fire/comm.c
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Device communications
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#include "comm.h"
+#include "chip.h"
+#include "midi.h"
+
+enum {
+	COMM_EP = 1,
+	COMM_FPGA_EP = 2
+};
+
+static void usb6fire_comm_init_urb(struct comm_runtime *rt, struct urb *urb,
+		u8 *buffer, void *context, void(*handler)(struct urb *urb))
+{
+	urb->transfer_buffer = buffer;
+	urb->pipe = usb_sndintpipe(rt->chip->dev, COMM_EP);
+	urb->complete = handler;
+	urb->context = context;
+	urb->interval = 1;
+	urb->dev = rt->chip->dev;
+}
+
+static void usb6fire_comm_receiver_handler(struct urb *urb)
+{
+	struct comm_runtime *rt = urb->context;
+	struct midi_runtime *midi_rt = rt->chip->midi;
+
+	if (!urb->status) {
+		u8 len = rt->receiver_buffer[1];
+
+		if (rt->receiver_buffer[0] == 0x10 && /* midi in event */
+		    len <= COMM_RECEIVER_BUFSIZE - 2 &&
+		    urb->actual_length >= len + 2)
+			if (midi_rt)
+				midi_rt->in_received(midi_rt,
+						rt->receiver_buffer + 2, len);
+	}
+
+	if (!rt->chip->shutdown) {
+		urb->status = 0;
+		urb->actual_length = 0;
+		if (usb_submit_urb(urb, GFP_ATOMIC) < 0)
+			dev_warn(&urb->dev->dev,
+					"comm data receiver aborted.\n");
+	}
+}
+
+static void usb6fire_comm_init_buffer(u8 *buffer, u8 id, u8 request,
+		u8 reg, u8 vl, u8 vh)
+{
+	buffer[0] = 0x01;
+	buffer[2] = request;
+	buffer[3] = id;
+	switch (request) {
+	case 0x02:
+		buffer[1] = 0x05; /* length (starting at buffer[2]) */
+		buffer[4] = reg;
+		buffer[5] = vl;
+		buffer[6] = vh;
+		break;
+
+	case 0x12:
+		buffer[1] = 0x0b; /* length (starting at buffer[2]) */
+		buffer[4] = 0x00;
+		buffer[5] = 0x18;
+		buffer[6] = 0x05;
+		buffer[7] = 0x00;
+		buffer[8] = 0x01;
+		buffer[9] = 0x00;
+		buffer[10] = 0x9e;
+		buffer[11] = reg;
+		buffer[12] = vl;
+		break;
+
+	case 0x20:
+	case 0x21:
+	case 0x22:
+		buffer[1] = 0x04;
+		buffer[4] = reg;
+		buffer[5] = vl;
+		break;
+	}
+}
+
+static int usb6fire_comm_send_buffer(u8 *buffer, struct usb_device *dev)
+{
+	int ret;
+	int actual_len;
+
+	ret = usb_interrupt_msg(dev, usb_sndintpipe(dev, COMM_EP),
+			buffer, buffer[1] + 2, &actual_len, 1000);
+	if (ret < 0)
+		return ret;
+	else if (actual_len != buffer[1] + 2)
+		return -EIO;
+	return 0;
+}
+
+static int usb6fire_comm_write8(struct comm_runtime *rt, u8 request,
+		u8 reg, u8 value)
+{
+	u8 *buffer;
+	int ret;
+
+	/* 13: maximum length of message */
+	buffer = kmalloc(13, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	usb6fire_comm_init_buffer(buffer, 0x00, request, reg, value, 0x00);
+	ret = usb6fire_comm_send_buffer(buffer, rt->chip->dev);
+
+	kfree(buffer);
+	return ret;
+}
+
+static int usb6fire_comm_write16(struct comm_runtime *rt, u8 request,
+		u8 reg, u8 vl, u8 vh)
+{
+	u8 *buffer;
+	int ret;
+
+	/* 13: maximum length of message */
+	buffer = kmalloc(13, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	usb6fire_comm_init_buffer(buffer, 0x00, request, reg, vl, vh);
+	ret = usb6fire_comm_send_buffer(buffer, rt->chip->dev);
+
+	kfree(buffer);
+	return ret;
+}
+
+static void usb6fire_comm_free(struct comm_runtime *rt)
+{
+	if (!rt)
+		return;
+
+	if (rt->chip)
+		rt->chip->comm = NULL;
+
+	usb_free_urb(rt->receiver);
+	kfree(rt->receiver_buffer);
+	kfree(rt);
+}
+
+int usb6fire_comm_init(struct sfire_chip *chip)
+{
+	struct comm_runtime *rt = kzalloc_obj(struct comm_runtime);
+	struct urb *urb;
+	int ret;
+
+	if (!rt)
+		return -ENOMEM;
+
+	rt->receiver_buffer = kzalloc(COMM_RECEIVER_BUFSIZE, GFP_KERNEL);
+	if (!rt->receiver_buffer) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!urb) {
+		ret = -ENOMEM;
+		goto error;
+	}
+	rt->receiver = urb;
+	rt->serial = 1;
+	rt->chip = chip;
+	rt->init_urb = usb6fire_comm_init_urb;
+	rt->write8 = usb6fire_comm_write8;
+	rt->write16 = usb6fire_comm_write16;
+
+	/* submit an urb that receives communication data from device */
+	urb->transfer_buffer = rt->receiver_buffer;
+	urb->transfer_buffer_length = COMM_RECEIVER_BUFSIZE;
+	urb->pipe = usb_rcvintpipe(chip->dev, COMM_EP);
+	urb->dev = chip->dev;
+	urb->complete = usb6fire_comm_receiver_handler;
+	urb->context = rt;
+	urb->interval = 1;
+	ret = usb_submit_urb(urb, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(&chip->dev->dev, "cannot create comm data receiver.");
+		goto error;
+	}
+	chip->comm = rt;
+	return 0;
+
+ error:
+	usb6fire_comm_free(rt);
+	return ret;
+}
+
+void usb6fire_comm_abort(struct sfire_chip *chip)
+{
+	struct comm_runtime *rt = chip->comm;
+
+	if (rt)
+		usb_poison_urb(rt->receiver);
+}
+
+void usb6fire_comm_destroy(struct sfire_chip *chip)
+{
+	usb6fire_comm_free(chip->comm);
+}
diff --git a/sound/usb/6fire/comm.h b/sound/usb/6fire/comm.h
new file mode 100644
index 000000000..89976f510
--- /dev/null
+++ b/sound/usb/6fire/comm.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+#ifndef USB6FIRE_COMM_H
+#define USB6FIRE_COMM_H
+
+#include "common.h"
+
+enum /* settings for comm */
+{
+	COMM_RECEIVER_BUFSIZE = 64,
+};
+
+struct comm_runtime {
+	struct sfire_chip *chip;
+
+	struct urb *receiver;
+	u8 *receiver_buffer;
+
+	u8 serial; /* urb serial */
+
+	void (*init_urb)(struct comm_runtime *rt, struct urb *urb, u8 *buffer,
+			void *context, void(*handler)(struct urb *urb));
+	/* writes control data to the device */
+	int (*write8)(struct comm_runtime *rt, u8 request, u8 reg, u8 value);
+	int (*write16)(struct comm_runtime *rt, u8 request, u8 reg,
+			u8 vh, u8 vl);
+};
+
+int usb6fire_comm_init(struct sfire_chip *chip);
+void usb6fire_comm_abort(struct sfire_chip *chip);
+void usb6fire_comm_destroy(struct sfire_chip *chip);
+#endif /* USB6FIRE_COMM_H */
+
diff --git a/sound/usb/6fire/common.h b/sound/usb/6fire/common.h
new file mode 100644
index 000000000..3a32c94b5
--- /dev/null
+++ b/sound/usb/6fire/common.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#ifndef USB6FIRE_COMMON_H
+#define USB6FIRE_COMMON_H
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <sound/core.h>
+
+#define PREFIX "6fire: "
+
+struct sfire_chip;
+struct midi_runtime;
+struct pcm_runtime;
+struct control_runtime;
+struct comm_runtime;
+#endif /* USB6FIRE_COMMON_H */
+
diff --git a/sound/usb/6fire/control.c b/sound/usb/6fire/control.c
new file mode 100644
index 000000000..10104cb42
--- /dev/null
+++ b/sound/usb/6fire/control.c
@@ -0,0 +1,619 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Mixer control
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ *
+ * Thanks to:
+ * - Holger Ruckdeschel: he found out how to control individual channel
+ *   volumes and introduced mute switch
+ */
+
+#include <linux/interrupt.h>
+#include <sound/control.h>
+#include <sound/tlv.h>
+
+#include "control.h"
+#include "comm.h"
+#include "chip.h"
+
+static const char * const opt_coax_texts[2] = { "Optical", "Coax" };
+static const char * const line_phono_texts[2] = { "Line", "Phono" };
+
+/*
+ * data that needs to be sent to device. sets up card internal stuff.
+ * values dumped from windows driver and filtered by trial'n'error.
+ */
+static const struct {
+	u8 type;
+	u8 reg;
+	u8 value;
+}
+init_data[] = {
+	{ 0x22, 0x00, 0x00 }, { 0x20, 0x00, 0x08 }, { 0x22, 0x01, 0x01 },
+	{ 0x20, 0x01, 0x08 }, { 0x22, 0x02, 0x00 }, { 0x20, 0x02, 0x08 },
+	{ 0x22, 0x03, 0x00 }, { 0x20, 0x03, 0x08 }, { 0x22, 0x04, 0x00 },
+	{ 0x20, 0x04, 0x08 }, { 0x22, 0x05, 0x01 }, { 0x20, 0x05, 0x08 },
+	{ 0x22, 0x04, 0x01 }, { 0x12, 0x04, 0x00 }, { 0x12, 0x05, 0x00 },
+	{ 0x12, 0x0d, 0x38 }, { 0x12, 0x21, 0x82 }, { 0x12, 0x22, 0x80 },
+	{ 0x12, 0x23, 0x00 }, { 0x12, 0x06, 0x02 }, { 0x12, 0x03, 0x00 },
+	{ 0x12, 0x02, 0x00 }, { 0x22, 0x03, 0x01 },
+	{ 0 } /* TERMINATING ENTRY */
+};
+
+static const int rates_altsetting[] = { 1, 1, 2, 2, 3, 3 };
+/* values to write to soundcard register for all samplerates */
+static const u16 rates_6fire_vl[] = {0x00, 0x01, 0x00, 0x01, 0x00, 0x01};
+static const u16 rates_6fire_vh[] = {0x11, 0x11, 0x10, 0x10, 0x00, 0x00};
+
+static DECLARE_TLV_DB_MINMAX(tlv_output, -9000, 0);
+static DECLARE_TLV_DB_MINMAX(tlv_input, -1500, 1500);
+
+enum {
+	DIGITAL_THRU_ONLY_SAMPLERATE = 3
+};
+
+static void usb6fire_control_output_vol_update(struct control_runtime *rt)
+{
+	struct comm_runtime *comm_rt = rt->chip->comm;
+	int i;
+
+	if (comm_rt)
+		for (i = 0; i < 6; i++)
+			if (!(rt->ovol_updated & (1 << i))) {
+				comm_rt->write8(comm_rt, 0x12, 0x0f + i,
+					180 - rt->output_vol[i]);
+				rt->ovol_updated |= 1 << i;
+			}
+}
+
+static void usb6fire_control_output_mute_update(struct control_runtime *rt)
+{
+	struct comm_runtime *comm_rt = rt->chip->comm;
+
+	if (comm_rt)
+		comm_rt->write8(comm_rt, 0x12, 0x0e, ~rt->output_mute);
+}
+
+static void usb6fire_control_input_vol_update(struct control_runtime *rt)
+{
+	struct comm_runtime *comm_rt = rt->chip->comm;
+	int i;
+
+	if (comm_rt)
+		for (i = 0; i < 2; i++)
+			if (!(rt->ivol_updated & (1 << i))) {
+				comm_rt->write8(comm_rt, 0x12, 0x1c + i,
+					rt->input_vol[i] & 0x3f);
+				rt->ivol_updated |= 1 << i;
+			}
+}
+
+static void usb6fire_control_line_phono_update(struct control_runtime *rt)
+{
+	struct comm_runtime *comm_rt = rt->chip->comm;
+	if (comm_rt) {
+		comm_rt->write8(comm_rt, 0x22, 0x02, rt->line_phono_switch);
+		comm_rt->write8(comm_rt, 0x21, 0x02, rt->line_phono_switch);
+	}
+}
+
+static void usb6fire_control_opt_coax_update(struct control_runtime *rt)
+{
+	struct comm_runtime *comm_rt = rt->chip->comm;
+	if (comm_rt) {
+		comm_rt->write8(comm_rt, 0x22, 0x00, rt->opt_coax_switch);
+		comm_rt->write8(comm_rt, 0x21, 0x00, rt->opt_coax_switch);
+	}
+}
+
+static int usb6fire_control_set_rate(struct control_runtime *rt, int rate)
+{
+	int ret;
+	struct usb_device *device = rt->chip->dev;
+	struct comm_runtime *comm_rt = rt->chip->comm;
+
+	if (rate < 0 || rate >= CONTROL_N_RATES)
+		return -EINVAL;
+
+	ret = usb_set_interface(device, 1, rates_altsetting[rate]);
+	if (ret < 0)
+		return ret;
+
+	/* set soundcard clock */
+	ret = comm_rt->write16(comm_rt, 0x02, 0x01, rates_6fire_vl[rate],
+			rates_6fire_vh[rate]);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int usb6fire_control_set_channels(
+	struct control_runtime *rt, int n_analog_out,
+	int n_analog_in, bool spdif_out, bool spdif_in)
+{
+	int ret;
+	struct comm_runtime *comm_rt = rt->chip->comm;
+
+	/* enable analog inputs and outputs
+	 * (one bit per stereo-channel) */
+	ret = comm_rt->write16(comm_rt, 0x02, 0x02,
+			(1 << (n_analog_out / 2)) - 1,
+			(1 << (n_analog_in / 2)) - 1);
+	if (ret < 0)
+		return ret;
+
+	/* disable digital inputs and outputs */
+	/* TODO: use spdif_x to enable/disable digital channels */
+	ret = comm_rt->write16(comm_rt, 0x02, 0x03, 0x00, 0x00);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int usb6fire_control_streaming_update(struct control_runtime *rt)
+{
+	struct comm_runtime *comm_rt = rt->chip->comm;
+
+	if (comm_rt) {
+		if (!rt->usb_streaming && rt->digital_thru_switch)
+			usb6fire_control_set_rate(rt,
+				DIGITAL_THRU_ONLY_SAMPLERATE);
+		return comm_rt->write16(comm_rt, 0x02, 0x00, 0x00,
+			(rt->usb_streaming ? 0x01 : 0x00) |
+			(rt->digital_thru_switch ? 0x08 : 0x00));
+	}
+	return -EINVAL;
+}
+
+static int usb6fire_control_output_vol_info(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 2;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 180;
+	return 0;
+}
+
+static int usb6fire_control_output_vol_put(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	unsigned int ch = kcontrol->private_value;
+	int changed = 0;
+
+	if (ch > 4) {
+		dev_err(&rt->chip->dev->dev,
+			"Invalid channel in volume control.");
+		return -EINVAL;
+	}
+
+	if (rt->output_vol[ch] != ucontrol->value.integer.value[0]) {
+		rt->output_vol[ch] = ucontrol->value.integer.value[0];
+		rt->ovol_updated &= ~(1 << ch);
+		changed = 1;
+	}
+	if (rt->output_vol[ch + 1] != ucontrol->value.integer.value[1]) {
+		rt->output_vol[ch + 1] = ucontrol->value.integer.value[1];
+		rt->ovol_updated &= ~(2 << ch);
+		changed = 1;
+	}
+
+	if (changed)
+		usb6fire_control_output_vol_update(rt);
+
+	return changed;
+}
+
+static int usb6fire_control_output_vol_get(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	unsigned int ch = kcontrol->private_value;
+
+	if (ch > 4) {
+		dev_err(&rt->chip->dev->dev,
+			"Invalid channel in volume control.");
+		return -EINVAL;
+	}
+
+	ucontrol->value.integer.value[0] = rt->output_vol[ch];
+	ucontrol->value.integer.value[1] = rt->output_vol[ch + 1];
+	return 0;
+}
+
+static int usb6fire_control_output_mute_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	unsigned int ch = kcontrol->private_value;
+	u8 old = rt->output_mute;
+	u8 value = 0;
+
+	if (ch > 4) {
+		dev_err(&rt->chip->dev->dev,
+			"Invalid channel in volume control.");
+		return -EINVAL;
+	}
+
+	rt->output_mute &= ~(3 << ch);
+	if (ucontrol->value.integer.value[0])
+		value |= 1;
+	if (ucontrol->value.integer.value[1])
+		value |= 2;
+	rt->output_mute |= value << ch;
+
+	if (rt->output_mute != old)
+		usb6fire_control_output_mute_update(rt);
+
+	return rt->output_mute != old;
+}
+
+static int usb6fire_control_output_mute_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	unsigned int ch = kcontrol->private_value;
+	u8 value = rt->output_mute >> ch;
+
+	if (ch > 4) {
+		dev_err(&rt->chip->dev->dev,
+			"Invalid channel in volume control.");
+		return -EINVAL;
+	}
+
+	ucontrol->value.integer.value[0] = 1 & value;
+	value >>= 1;
+	ucontrol->value.integer.value[1] = 1 & value;
+
+	return 0;
+}
+
+static int usb6fire_control_input_vol_info(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 2;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 30;
+	return 0;
+}
+
+static int usb6fire_control_input_vol_put(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	int vol0 = ucontrol->value.integer.value[0] - 15;
+	int vol1 = ucontrol->value.integer.value[1] - 15;
+	int changed = 0;
+
+	if (rt->input_vol[0] != vol0) {
+		rt->input_vol[0] = vol0;
+		rt->ivol_updated &= ~(1 << 0);
+		changed = 1;
+	}
+	if (rt->input_vol[1] != vol1) {
+		rt->input_vol[1] = vol1;
+		rt->ivol_updated &= ~(1 << 1);
+		changed = 1;
+	}
+
+	if (changed)
+		usb6fire_control_input_vol_update(rt);
+
+	return changed;
+}
+
+static int usb6fire_control_input_vol_get(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+
+	ucontrol->value.integer.value[0] = rt->input_vol[0] + 15;
+	ucontrol->value.integer.value[1] = rt->input_vol[1] + 15;
+
+	return 0;
+}
+
+static int usb6fire_control_line_phono_info(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_info *uinfo)
+{
+	return snd_ctl_enum_info(uinfo, 1, 2, line_phono_texts);
+}
+
+static int usb6fire_control_line_phono_put(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	int changed = 0;
+	if (rt->line_phono_switch != ucontrol->value.integer.value[0]) {
+		rt->line_phono_switch = ucontrol->value.integer.value[0];
+		usb6fire_control_line_phono_update(rt);
+		changed = 1;
+	}
+	return changed;
+}
+
+static int usb6fire_control_line_phono_get(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	ucontrol->value.integer.value[0] = rt->line_phono_switch;
+	return 0;
+}
+
+static int usb6fire_control_opt_coax_info(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_info *uinfo)
+{
+	return snd_ctl_enum_info(uinfo, 1, 2, opt_coax_texts);
+}
+
+static int usb6fire_control_opt_coax_put(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	int changed = 0;
+
+	if (rt->opt_coax_switch != ucontrol->value.enumerated.item[0]) {
+		rt->opt_coax_switch = ucontrol->value.enumerated.item[0];
+		usb6fire_control_opt_coax_update(rt);
+		changed = 1;
+	}
+	return changed;
+}
+
+static int usb6fire_control_opt_coax_get(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	ucontrol->value.enumerated.item[0] = rt->opt_coax_switch;
+	return 0;
+}
+
+static int usb6fire_control_digital_thru_put(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	int changed = 0;
+
+	if (rt->digital_thru_switch != ucontrol->value.integer.value[0]) {
+		rt->digital_thru_switch = ucontrol->value.integer.value[0];
+		usb6fire_control_streaming_update(rt);
+		changed = 1;
+	}
+	return changed;
+}
+
+static int usb6fire_control_digital_thru_get(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct control_runtime *rt = snd_kcontrol_chip(kcontrol);
+	ucontrol->value.integer.value[0] = rt->digital_thru_switch;
+	return 0;
+}
+
+static const struct snd_kcontrol_new vol_elements[] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Analog Playback Volume",
+		.index = 0,
+		.private_value = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+			SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+		.info = usb6fire_control_output_vol_info,
+		.get = usb6fire_control_output_vol_get,
+		.put = usb6fire_control_output_vol_put,
+		.tlv = { .p = tlv_output }
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Analog Playback Volume",
+		.index = 1,
+		.private_value = 2,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+			SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+		.info = usb6fire_control_output_vol_info,
+		.get = usb6fire_control_output_vol_get,
+		.put = usb6fire_control_output_vol_put,
+		.tlv = { .p = tlv_output }
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Analog Playback Volume",
+		.index = 2,
+		.private_value = 4,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+			SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+		.info = usb6fire_control_output_vol_info,
+		.get = usb6fire_control_output_vol_get,
+		.put = usb6fire_control_output_vol_put,
+		.tlv = { .p = tlv_output }
+	},
+	{}
+};
+
+static const struct snd_kcontrol_new mute_elements[] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Analog Playback Switch",
+		.index = 0,
+		.private_value = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_ctl_boolean_stereo_info,
+		.get = usb6fire_control_output_mute_get,
+		.put = usb6fire_control_output_mute_put,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Analog Playback Switch",
+		.index = 1,
+		.private_value = 2,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_ctl_boolean_stereo_info,
+		.get = usb6fire_control_output_mute_get,
+		.put = usb6fire_control_output_mute_put,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Analog Playback Switch",
+		.index = 2,
+		.private_value = 4,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_ctl_boolean_stereo_info,
+		.get = usb6fire_control_output_mute_get,
+		.put = usb6fire_control_output_mute_put,
+	},
+	{}
+};
+
+static const struct snd_kcontrol_new elements[] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Line/Phono Capture Route",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = usb6fire_control_line_phono_info,
+		.get = usb6fire_control_line_phono_get,
+		.put = usb6fire_control_line_phono_put
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Opt/Coax Capture Route",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = usb6fire_control_opt_coax_info,
+		.get = usb6fire_control_opt_coax_get,
+		.put = usb6fire_control_opt_coax_put
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Digital Thru Playback Route",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_ctl_boolean_mono_info,
+		.get = usb6fire_control_digital_thru_get,
+		.put = usb6fire_control_digital_thru_put
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Analog Capture Volume",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+			SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+		.info = usb6fire_control_input_vol_info,
+		.get = usb6fire_control_input_vol_get,
+		.put = usb6fire_control_input_vol_put,
+		.tlv = { .p = tlv_input }
+	},
+	{}
+};
+
+static int usb6fire_control_add_virtual(
+	struct control_runtime *rt,
+	struct snd_card *card,
+	char *name,
+	const struct snd_kcontrol_new *elems)
+{
+	int ret;
+	int i;
+	struct snd_kcontrol *vmaster =
+		snd_ctl_make_virtual_master(name, tlv_output);
+	struct snd_kcontrol *control;
+
+	if (!vmaster)
+		return -ENOMEM;
+	ret = snd_ctl_add(card, vmaster);
+	if (ret < 0)
+		return ret;
+
+	i = 0;
+	while (elems[i].name) {
+		control = snd_ctl_new1(&elems[i], rt);
+		if (!control)
+			return -ENOMEM;
+		ret = snd_ctl_add(card, control);
+		if (ret < 0)
+			return ret;
+		ret = snd_ctl_add_follower(vmaster, control);
+		if (ret < 0)
+			return ret;
+		i++;
+	}
+	return 0;
+}
+
+int usb6fire_control_init(struct sfire_chip *chip)
+{
+	int i;
+	int ret;
+	struct control_runtime *rt = kzalloc_obj(struct control_runtime);
+	struct comm_runtime *comm_rt = chip->comm;
+
+	if (!rt)
+		return -ENOMEM;
+
+	rt->chip = chip;
+	rt->update_streaming = usb6fire_control_streaming_update;
+	rt->set_rate = usb6fire_control_set_rate;
+	rt->set_channels = usb6fire_control_set_channels;
+
+	i = 0;
+	while (init_data[i].type) {
+		comm_rt->write8(comm_rt, init_data[i].type, init_data[i].reg,
+				init_data[i].value);
+		i++;
+	}
+
+	usb6fire_control_opt_coax_update(rt);
+	usb6fire_control_line_phono_update(rt);
+	usb6fire_control_output_vol_update(rt);
+	usb6fire_control_output_mute_update(rt);
+	usb6fire_control_input_vol_update(rt);
+	usb6fire_control_streaming_update(rt);
+
+	ret = usb6fire_control_add_virtual(rt, chip->card,
+		"Master Playback Volume", vol_elements);
+	if (ret) {
+		dev_err(&chip->dev->dev, "cannot add control.\n");
+		goto free_rt;
+	}
+	ret = usb6fire_control_add_virtual(rt, chip->card,
+		"Master Playback Switch", mute_elements);
+	if (ret) {
+		dev_err(&chip->dev->dev, "cannot add control.\n");
+		goto free_rt;
+	}
+
+	i = 0;
+	while (elements[i].name) {
+		ret = snd_ctl_add(chip->card, snd_ctl_new1(&elements[i], rt));
+		if (ret < 0) {
+			dev_err(&chip->dev->dev, "cannot add control.\n");
+			goto free_rt;
+		}
+		i++;
+	}
+
+	chip->control = rt;
+	return 0;
+
+free_rt:
+	kfree(rt);
+	return ret;
+}
+
+void usb6fire_control_abort(struct sfire_chip *chip)
+{}
+
+void usb6fire_control_destroy(struct sfire_chip *chip)
+{
+	kfree(chip->control);
+	chip->control = NULL;
+}
diff --git a/sound/usb/6fire/control.h b/sound/usb/6fire/control.h
new file mode 100644
index 000000000..ae57704d9
--- /dev/null
+++ b/sound/usb/6fire/control.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#ifndef USB6FIRE_CONTROL_H
+#define USB6FIRE_CONTROL_H
+
+#include "common.h"
+
+enum {
+	CONTROL_MAX_ELEMENTS = 32
+};
+
+enum {
+	CONTROL_RATE_44KHZ,
+	CONTROL_RATE_48KHZ,
+	CONTROL_RATE_88KHZ,
+	CONTROL_RATE_96KHZ,
+	CONTROL_RATE_176KHZ,
+	CONTROL_RATE_192KHZ,
+	CONTROL_N_RATES
+};
+
+struct control_runtime {
+	int (*update_streaming)(struct control_runtime *rt);
+	int (*set_rate)(struct control_runtime *rt, int rate);
+	int (*set_channels)(struct control_runtime *rt, int n_analog_out,
+		int n_analog_in, bool spdif_out, bool spdif_in);
+
+	struct sfire_chip *chip;
+
+	struct snd_kcontrol *element[CONTROL_MAX_ELEMENTS];
+	bool opt_coax_switch;
+	bool line_phono_switch;
+	bool digital_thru_switch;
+	bool usb_streaming;
+	u8 output_vol[6];
+	u8 ovol_updated;
+	u8 output_mute;
+	s8 input_vol[2];
+	u8 ivol_updated;
+};
+
+int usb6fire_control_init(struct sfire_chip *chip);
+void usb6fire_control_abort(struct sfire_chip *chip);
+void usb6fire_control_destroy(struct sfire_chip *chip);
+#endif /* USB6FIRE_CONTROL_H */
+
diff --git a/sound/usb/6fire/firmware.c b/sound/usb/6fire/firmware.c
new file mode 100644
index 000000000..d9dd8f44b
--- /dev/null
+++ b/sound/usb/6fire/firmware.c
@@ -0,0 +1,389 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Firmware loader
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/bitrev.h>
+#include <linux/hex.h>
+#include <linux/kernel.h>
+
+#include "firmware.h"
+#include "chip.h"
+
+MODULE_FIRMWARE("6fire/dmx6firel2.ihx");
+MODULE_FIRMWARE("6fire/dmx6fireap.ihx");
+MODULE_FIRMWARE("6fire/dmx6firecf.bin");
+
+enum {
+	FPGA_BUFSIZE = 512, FPGA_EP = 2
+};
+
+/*
+ * wMaxPacketSize of pcm endpoints.
+ * keep synced with rates_in_packet_size and rates_out_packet_size in pcm.c
+ * fpp: frames per isopacket
+ *
+ * CAUTION: keep sizeof <= buffer[] in usb6fire_fw_init
+ */
+static const u8 ep_w_max_packet_size[] = {
+	0xe4, 0x00, 0xe4, 0x00, /* alt 1: 228 EP2 and EP6 (7 fpp) */
+	0xa4, 0x01, 0xa4, 0x01, /* alt 2: 420 EP2 and EP6 (13 fpp)*/
+	0x94, 0x01, 0x5c, 0x02  /* alt 3: 404 EP2 and 604 EP6 (25 fpp) */
+};
+
+static const u8 known_fw_versions[][2] = {
+	{ 0x03, 0x01 }
+};
+
+struct ihex_record {
+	u16 address;
+	u8 len;
+	u8 data[256];
+	char error; /* true if an error occurred parsing this record */
+
+	u8 max_len; /* maximum record length in whole ihex */
+
+	/* private */
+	const char *txt_data;
+	unsigned int txt_length;
+	unsigned int txt_offset; /* current position in txt_data */
+};
+
+static u8 usb6fire_fw_ihex_hex(const u8 *data, u8 *crc)
+{
+	u8 val = 0;
+	int hval;
+
+	hval = hex_to_bin(data[0]);
+	if (hval >= 0)
+		val |= (hval << 4);
+
+	hval = hex_to_bin(data[1]);
+	if (hval >= 0)
+		val |= hval;
+
+	*crc += val;
+	return val;
+}
+
+/*
+ * returns true if record is available, false otherwise.
+ * iff an error occurred, false will be returned and record->error will be true.
+ */
+static bool usb6fire_fw_ihex_next_record(struct ihex_record *record)
+{
+	u8 crc = 0;
+	u8 type;
+	int i;
+
+	record->error = false;
+
+	/* find begin of record (marked by a colon) */
+	while (record->txt_offset < record->txt_length
+			&& record->txt_data[record->txt_offset] != ':')
+		record->txt_offset++;
+	if (record->txt_offset == record->txt_length)
+		return false;
+
+	/* number of characters needed for len, addr and type entries */
+	record->txt_offset++;
+	if (record->txt_offset + 8 > record->txt_length) {
+		record->error = true;
+		return false;
+	}
+
+	record->len = usb6fire_fw_ihex_hex(record->txt_data +
+			record->txt_offset, &crc);
+	record->txt_offset += 2;
+	record->address = usb6fire_fw_ihex_hex(record->txt_data +
+			record->txt_offset, &crc) << 8;
+	record->txt_offset += 2;
+	record->address |= usb6fire_fw_ihex_hex(record->txt_data +
+			record->txt_offset, &crc);
+	record->txt_offset += 2;
+	type = usb6fire_fw_ihex_hex(record->txt_data +
+			record->txt_offset, &crc);
+	record->txt_offset += 2;
+
+	/* number of characters needed for data and crc entries */
+	if (record->txt_offset + 2 * (record->len + 1) > record->txt_length) {
+		record->error = true;
+		return false;
+	}
+	for (i = 0; i < record->len; i++) {
+		record->data[i] = usb6fire_fw_ihex_hex(record->txt_data
+				+ record->txt_offset, &crc);
+		record->txt_offset += 2;
+	}
+	usb6fire_fw_ihex_hex(record->txt_data + record->txt_offset, &crc);
+	if (crc) {
+		record->error = true;
+		return false;
+	}
+
+	if (type == 1 || !record->len) /* eof */
+		return false;
+	else if (type == 0)
+		return true;
+	else {
+		record->error = true;
+		return false;
+	}
+}
+
+static int usb6fire_fw_ihex_init(const struct firmware *fw,
+		struct ihex_record *record)
+{
+	record->txt_data = fw->data;
+	record->txt_length = fw->size;
+	record->txt_offset = 0;
+	record->max_len = 0;
+	/* read all records, if loop ends, record->error indicates,
+	 * whether ihex is valid. */
+	while (usb6fire_fw_ihex_next_record(record))
+		record->max_len = max(record->len, record->max_len);
+	if (record->error)
+		return -EINVAL;
+	record->txt_offset = 0;
+	return 0;
+}
+
+static int usb6fire_fw_ezusb_write(struct usb_device *device,
+		int type, int value, char *data, int len)
+{
+	return usb_control_msg_send(device, 0, type,
+				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+				    value, 0, data, len, 1000, GFP_KERNEL);
+}
+
+static int usb6fire_fw_ezusb_read(struct usb_device *device,
+		int type, int value, char *data, int len)
+{
+	return usb_control_msg_recv(device, 0, type,
+				    USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+				    value, 0, data, len, 1000, GFP_KERNEL);
+}
+
+static int usb6fire_fw_fpga_write(struct usb_device *device,
+		char *data, int len)
+{
+	int actual_len;
+	int ret;
+
+	ret = usb_bulk_msg(device, usb_sndbulkpipe(device, FPGA_EP), data, len,
+			&actual_len, 1000);
+	if (ret < 0)
+		return ret;
+	else if (actual_len != len)
+		return -EIO;
+	return 0;
+}
+
+static int usb6fire_fw_ezusb_upload(
+		struct usb_interface *intf, const char *fwname,
+		unsigned int postaddr, u8 *postdata, unsigned int postlen)
+{
+	int ret;
+	u8 data;
+	struct usb_device *device = interface_to_usbdev(intf);
+	struct ihex_record *rec __free(kfree) = kmalloc_obj(struct ihex_record);
+
+	if (!rec)
+		return -ENOMEM;
+
+	const struct firmware *fw __free(firmware) = NULL;
+	ret = request_firmware(&fw, fwname, &device->dev);
+	if (ret < 0) {
+		dev_err(&intf->dev,
+			"error requesting ezusb firmware %s.\n", fwname);
+		return ret;
+	}
+	ret = usb6fire_fw_ihex_init(fw, rec);
+	if (ret < 0) {
+		dev_err(&intf->dev,
+			"error validating ezusb firmware %s.\n", fwname);
+		return ret;
+	}
+	/* upload firmware image */
+	data = 0x01; /* stop ezusb cpu */
+	ret = usb6fire_fw_ezusb_write(device, 0xa0, 0xe600, &data, 1);
+	if (ret) {
+		dev_err(&intf->dev,
+			"unable to upload ezusb firmware %s: begin message.\n",
+			fwname);
+		return ret;
+	}
+
+	while (usb6fire_fw_ihex_next_record(rec)) { /* write firmware */
+		ret = usb6fire_fw_ezusb_write(device, 0xa0, rec->address,
+				rec->data, rec->len);
+		if (ret) {
+			dev_err(&intf->dev,
+				"unable to upload ezusb firmware %s: data urb.\n",
+				fwname);
+			return ret;
+		}
+	}
+
+	if (postdata) { /* write data after firmware has been uploaded */
+		ret = usb6fire_fw_ezusb_write(device, 0xa0, postaddr,
+				postdata, postlen);
+		if (ret) {
+			dev_err(&intf->dev,
+				"unable to upload ezusb firmware %s: post urb.\n",
+				fwname);
+			return ret;
+		}
+	}
+
+	data = 0x00; /* resume ezusb cpu */
+	ret = usb6fire_fw_ezusb_write(device, 0xa0, 0xe600, &data, 1);
+	if (ret) {
+		dev_err(&intf->dev,
+			"unable to upload ezusb firmware %s: end message.\n",
+			fwname);
+		return ret;
+	}
+	return 0;
+}
+
+static int usb6fire_fw_fpga_upload(
+		struct usb_interface *intf, const char *fwname)
+{
+	int ret;
+	int i;
+	struct usb_device *device = interface_to_usbdev(intf);
+	u8 *buffer __free(kfree) = kmalloc(FPGA_BUFSIZE, GFP_KERNEL);
+	const char *c;
+	const char *end;
+
+	if (!buffer)
+		return -ENOMEM;
+
+	const struct firmware *fw __free(firmware) = NULL;
+	ret = request_firmware(&fw, fwname, &device->dev);
+	if (ret < 0) {
+		dev_err(&intf->dev, "unable to get fpga firmware %s.\n",
+				fwname);
+		return -EIO;
+	}
+
+	c = fw->data;
+	end = fw->data + fw->size;
+
+	ret = usb6fire_fw_ezusb_write(device, 8, 0, NULL, 0);
+	if (ret) {
+		dev_err(&intf->dev,
+			"unable to upload fpga firmware: begin urb.\n");
+		return ret;
+	}
+
+	while (c != end) {
+		for (i = 0; c != end && i < FPGA_BUFSIZE; i++, c++)
+			buffer[i] = bitrev8((u8)*c);
+
+		ret = usb6fire_fw_fpga_write(device, buffer, i);
+		if (ret < 0) {
+			dev_err(&intf->dev,
+				"unable to upload fpga firmware: fw urb.\n");
+			return ret;
+		}
+	}
+
+	ret = usb6fire_fw_ezusb_write(device, 9, 0, NULL, 0);
+	if (ret) {
+		dev_err(&intf->dev,
+			"unable to upload fpga firmware: end urb.\n");
+		return ret;
+	}
+	return 0;
+}
+
+/* check, if the firmware version the devices has currently loaded
+ * is known by this driver. 'version' needs to have 4 bytes version
+ * info data. */
+static int usb6fire_fw_check(struct usb_interface *intf, const u8 *version)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(known_fw_versions); i++)
+		if (!memcmp(version, known_fw_versions + i, 2))
+			return 0;
+
+	dev_err(&intf->dev, "invalid firmware version in device: %4ph. "
+			"please reconnect to power. if this failure "
+			"still happens, check your firmware installation.",
+			version);
+	return -EINVAL;
+}
+
+int usb6fire_fw_init(struct usb_interface *intf)
+{
+	int i;
+	int ret;
+	struct usb_device *device = interface_to_usbdev(intf);
+	/* buffer: 8 receiving bytes from device and
+	 * sizeof(EP_W_MAX_PACKET_SIZE) bytes for non-const copy */
+	u8 buffer[12];
+
+	ret = usb6fire_fw_ezusb_read(device, 1, 0, buffer, 8);
+	if (ret) {
+		dev_err(&intf->dev,
+			"unable to receive device firmware state.\n");
+		return ret;
+	}
+	if (buffer[0] != 0xeb || buffer[1] != 0xaa || buffer[2] != 0x55) {
+		dev_err(&intf->dev,
+			"unknown device firmware state received from device:");
+		for (i = 0; i < 8; i++)
+			printk(KERN_CONT "%02x ", buffer[i]);
+		printk(KERN_CONT "\n");
+		return -EIO;
+	}
+	/* do we need fpga loader ezusb firmware? */
+	if (buffer[3] == 0x01) {
+		ret = usb6fire_fw_ezusb_upload(intf,
+				"6fire/dmx6firel2.ihx", 0, NULL, 0);
+		if (ret < 0)
+			return ret;
+		return FW_NOT_READY;
+	}
+	/* do we need fpga firmware and application ezusb firmware? */
+	else if (buffer[3] == 0x02) {
+		ret = usb6fire_fw_check(intf, buffer + 4);
+		if (ret < 0)
+			return ret;
+		ret = usb6fire_fw_fpga_upload(intf, "6fire/dmx6firecf.bin");
+		if (ret < 0)
+			return ret;
+		memcpy(buffer, ep_w_max_packet_size,
+				sizeof(ep_w_max_packet_size));
+		ret = usb6fire_fw_ezusb_upload(intf, "6fire/dmx6fireap.ihx",
+				0x0003,	buffer, sizeof(ep_w_max_packet_size));
+		if (ret < 0)
+			return ret;
+		return FW_NOT_READY;
+	}
+	/* all fw loaded? */
+	else if (buffer[3] == 0x03)
+		return usb6fire_fw_check(intf, buffer + 4);
+	/* unknown data? */
+	else {
+		dev_err(&intf->dev,
+			"unknown device firmware state received from device: ");
+		for (i = 0; i < 8; i++)
+			printk(KERN_CONT "%02x ", buffer[i]);
+		printk(KERN_CONT "\n");
+		return -EIO;
+	}
+	return 0;
+}
+
diff --git a/sound/usb/6fire/firmware.h b/sound/usb/6fire/firmware.h
new file mode 100644
index 000000000..c29ed9cd2
--- /dev/null
+++ b/sound/usb/6fire/firmware.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Author: Torsten Schenk
+ * Created: Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#ifndef USB6FIRE_FIRMWARE_H
+#define USB6FIRE_FIRMWARE_H
+
+#include "common.h"
+
+enum /* firmware state of device */
+{
+	FW_READY = 0,
+	FW_NOT_READY = 1
+};
+
+int usb6fire_fw_init(struct usb_interface *intf);
+#endif /* USB6FIRE_FIRMWARE_H */
+
diff --git a/sound/usb/6fire/midi.c b/sound/usb/6fire/midi.c
new file mode 100644
index 000000000..279b44993
--- /dev/null
+++ b/sound/usb/6fire/midi.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Rawmidi driver
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#include <sound/rawmidi.h>
+
+#include "midi.h"
+#include "chip.h"
+#include "comm.h"
+
+enum {
+	MIDI_BUFSIZE = 64
+};
+
+static void usb6fire_midi_out_handler(struct urb *urb)
+{
+	struct midi_runtime *rt = urb->context;
+	int ret;
+
+	guard(spinlock_irqsave)(&rt->out_lock);
+
+	if (rt->out) {
+		ret = snd_rawmidi_transmit(rt->out, rt->out_buffer + 4,
+				MIDI_BUFSIZE - 4);
+		if (ret > 0) { /* more data available, send next packet */
+			rt->out_buffer[1] = ret + 2;
+			rt->out_buffer[3] = rt->out_serial++;
+			urb->transfer_buffer_length = ret + 4;
+
+			ret = usb_submit_urb(urb, GFP_ATOMIC);
+			if (ret < 0)
+				dev_err(&urb->dev->dev,
+					"midi out urb submit failed: %d\n",
+					ret);
+		} else /* no more data to transmit */
+			rt->out = NULL;
+	}
+}
+
+static void usb6fire_midi_in_received(
+		struct midi_runtime *rt, u8 *data, int length)
+{
+	guard(spinlock_irqsave)(&rt->in_lock);
+	if (rt->in)
+		snd_rawmidi_receive(rt->in, data, length);
+}
+
+static int usb6fire_midi_out_open(struct snd_rawmidi_substream *alsa_sub)
+{
+	return 0;
+}
+
+static int usb6fire_midi_out_close(struct snd_rawmidi_substream *alsa_sub)
+{
+	return 0;
+}
+
+static void usb6fire_midi_out_trigger(
+		struct snd_rawmidi_substream *alsa_sub, int up)
+{
+	struct midi_runtime *rt = alsa_sub->rmidi->private_data;
+	struct urb *urb = rt->out_urb;
+	__s8 ret;
+
+	guard(spinlock_irqsave)(&rt->out_lock);
+	if (up) { /* start transfer */
+		if (rt->out) /* we are already transmitting so just return */
+			return;
+
+		ret = snd_rawmidi_transmit(alsa_sub, rt->out_buffer + 4,
+				MIDI_BUFSIZE - 4);
+		if (ret > 0) {
+			rt->out_buffer[1] = ret + 2;
+			rt->out_buffer[3] = rt->out_serial++;
+			urb->transfer_buffer_length = ret + 4;
+
+			ret = usb_submit_urb(urb, GFP_ATOMIC);
+			if (ret < 0)
+				dev_err(&urb->dev->dev,
+					"midi out urb submit failed: %d\n",
+					ret);
+			else
+				rt->out = alsa_sub;
+		}
+	} else if (rt->out == alsa_sub)
+		rt->out = NULL;
+}
+
+static void usb6fire_midi_out_drain(struct snd_rawmidi_substream *alsa_sub)
+{
+	struct midi_runtime *rt = alsa_sub->rmidi->private_data;
+	int retry = 0;
+
+	while (rt->out && retry++ < 100)
+		msleep(10);
+}
+
+static int usb6fire_midi_in_open(struct snd_rawmidi_substream *alsa_sub)
+{
+	return 0;
+}
+
+static int usb6fire_midi_in_close(struct snd_rawmidi_substream *alsa_sub)
+{
+	return 0;
+}
+
+static void usb6fire_midi_in_trigger(
+		struct snd_rawmidi_substream *alsa_sub, int up)
+{
+	struct midi_runtime *rt = alsa_sub->rmidi->private_data;
+
+	guard(spinlock_irqsave)(&rt->in_lock);
+	if (up)
+		rt->in = alsa_sub;
+	else
+		rt->in = NULL;
+}
+
+static const struct snd_rawmidi_ops out_ops = {
+	.open = usb6fire_midi_out_open,
+	.close = usb6fire_midi_out_close,
+	.trigger = usb6fire_midi_out_trigger,
+	.drain = usb6fire_midi_out_drain
+};
+
+static const struct snd_rawmidi_ops in_ops = {
+	.open = usb6fire_midi_in_open,
+	.close = usb6fire_midi_in_close,
+	.trigger = usb6fire_midi_in_trigger
+};
+
+static void usb6fire_midi_free(struct midi_runtime *rt)
+{
+	if (!rt)
+		return;
+
+	if (rt->chip)
+		rt->chip->midi = NULL;
+
+	usb_free_urb(rt->out_urb);
+	kfree(rt->out_buffer);
+	kfree(rt);
+}
+
+int usb6fire_midi_init(struct sfire_chip *chip)
+{
+	int ret;
+	struct midi_runtime *rt = kzalloc_obj(struct midi_runtime);
+	struct comm_runtime *comm_rt = chip->comm;
+
+	if (!rt)
+		return -ENOMEM;
+
+	rt->out_buffer = kzalloc(MIDI_BUFSIZE, GFP_KERNEL);
+	if (!rt->out_buffer) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	rt->out_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!rt->out_urb) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	rt->chip = chip;
+	rt->in_received = usb6fire_midi_in_received;
+	rt->out_buffer[0] = 0x80; /* 'send midi' command */
+	rt->out_buffer[1] = 0x00; /* size of data */
+	rt->out_buffer[2] = 0x00; /* always 0 */
+	spin_lock_init(&rt->in_lock);
+	spin_lock_init(&rt->out_lock);
+
+	comm_rt->init_urb(comm_rt, rt->out_urb, rt->out_buffer, rt,
+			usb6fire_midi_out_handler);
+
+	ret = snd_rawmidi_new(chip->card, "6FireUSB", 0, 1, 1, &rt->instance);
+	if (ret < 0) {
+		dev_err(&chip->dev->dev, "unable to create midi.\n");
+		goto error;
+	}
+	rt->instance->private_data = rt;
+	strscpy(rt->instance->name, "DMX6FireUSB MIDI");
+	rt->instance->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
+			SNDRV_RAWMIDI_INFO_INPUT |
+			SNDRV_RAWMIDI_INFO_DUPLEX;
+	snd_rawmidi_set_ops(rt->instance, SNDRV_RAWMIDI_STREAM_OUTPUT,
+			&out_ops);
+	snd_rawmidi_set_ops(rt->instance, SNDRV_RAWMIDI_STREAM_INPUT,
+			&in_ops);
+
+	chip->midi = rt;
+	return 0;
+
+ error:
+	usb6fire_midi_free(rt);
+	return ret;
+}
+
+void usb6fire_midi_abort(struct sfire_chip *chip)
+{
+	struct midi_runtime *rt = chip->midi;
+
+	if (rt)
+		usb_poison_urb(rt->out_urb);
+}
+
+void usb6fire_midi_destroy(struct sfire_chip *chip)
+{
+	usb6fire_midi_free(chip->midi);
+}
diff --git a/sound/usb/6fire/midi.h b/sound/usb/6fire/midi.h
new file mode 100644
index 000000000..8716ab8a8
--- /dev/null
+++ b/sound/usb/6fire/midi.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#ifndef USB6FIRE_MIDI_H
+#define USB6FIRE_MIDI_H
+
+#include "common.h"
+
+struct midi_runtime {
+	struct sfire_chip *chip;
+	struct snd_rawmidi *instance;
+
+	struct snd_rawmidi_substream *in;
+	char in_active;
+
+	spinlock_t in_lock;
+	spinlock_t out_lock;
+	struct snd_rawmidi_substream *out;
+	struct urb *out_urb;
+	u8 out_serial; /* serial number of out packet */
+	u8 *out_buffer;
+	int buffer_offset;
+
+	void (*in_received)(struct midi_runtime *rt, u8 *data, int length);
+};
+
+int usb6fire_midi_init(struct sfire_chip *chip);
+void usb6fire_midi_abort(struct sfire_chip *chip);
+void usb6fire_midi_destroy(struct sfire_chip *chip);
+#endif /* USB6FIRE_MIDI_H */
+
diff --git a/sound/usb/6fire/pcm.c b/sound/usb/6fire/pcm.c
new file mode 100644
index 000000000..0285d79ac
--- /dev/null
+++ b/sound/usb/6fire/pcm.c
@@ -0,0 +1,700 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * PCM driver
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#include "pcm.h"
+#include "chip.h"
+#include "comm.h"
+#include "control.h"
+
+enum {
+	OUT_N_CHANNELS = 6, IN_N_CHANNELS = 4
+};
+
+/* keep next two synced with
+ * FW_EP_W_MAX_PACKET_SIZE[] and RATES_MAX_PACKET_SIZE
+ * and CONTROL_RATE_XXX in control.h */
+static const int rates_in_packet_size[] = { 228, 228, 420, 420, 404, 404 };
+static const int rates_out_packet_size[] = { 228, 228, 420, 420, 604, 604 };
+static const int rates[] = { 44100, 48000, 88200, 96000, 176400, 192000 };
+static const int rates_alsaid[] = {
+	SNDRV_PCM_RATE_44100, SNDRV_PCM_RATE_48000,
+	SNDRV_PCM_RATE_88200, SNDRV_PCM_RATE_96000,
+	SNDRV_PCM_RATE_176400, SNDRV_PCM_RATE_192000 };
+
+enum { /* settings for pcm */
+	OUT_EP = 6, IN_EP = 2, MAX_BUFSIZE = 128 * 1024
+};
+
+enum { /* pcm streaming states */
+	STREAM_DISABLED, /* no pcm streaming */
+	STREAM_STARTING, /* pcm streaming requested, waiting to become ready */
+	STREAM_RUNNING, /* pcm streaming running */
+	STREAM_STOPPING
+};
+
+static const struct snd_pcm_hardware pcm_hw = {
+	.info = SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_BLOCK_TRANSFER |
+		SNDRV_PCM_INFO_MMAP_VALID |
+		SNDRV_PCM_INFO_BATCH,
+
+	.formats = SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE,
+
+	.rates = SNDRV_PCM_RATE_44100 |
+		SNDRV_PCM_RATE_48000 |
+		SNDRV_PCM_RATE_88200 |
+		SNDRV_PCM_RATE_96000 |
+		SNDRV_PCM_RATE_176400 |
+		SNDRV_PCM_RATE_192000,
+
+	.rate_min = 44100,
+	.rate_max = 192000,
+	.channels_min = 1,
+	.channels_max = 0, /* set in pcm_open, depending on capture/playback */
+	.buffer_bytes_max = MAX_BUFSIZE,
+	.period_bytes_min = PCM_N_PACKETS_PER_URB * (PCM_MAX_PACKET_SIZE - 4),
+	.period_bytes_max = MAX_BUFSIZE,
+	.periods_min = 2,
+	.periods_max = 1024
+};
+
+static int usb6fire_pcm_set_rate(struct pcm_runtime *rt)
+{
+	int ret;
+	struct control_runtime *ctrl_rt = rt->chip->control;
+
+	ctrl_rt->usb_streaming = false;
+	ret = ctrl_rt->update_streaming(ctrl_rt);
+	if (ret < 0) {
+		dev_err(&rt->chip->dev->dev,
+			"error stopping streaming while setting samplerate %d.\n",
+			rates[rt->rate]);
+		return ret;
+	}
+
+	ret = ctrl_rt->set_rate(ctrl_rt, rt->rate);
+	if (ret < 0) {
+		dev_err(&rt->chip->dev->dev,
+			"error setting samplerate %d.\n",
+			rates[rt->rate]);
+		return ret;
+	}
+
+	ret = ctrl_rt->set_channels(ctrl_rt, OUT_N_CHANNELS, IN_N_CHANNELS,
+			false, false);
+	if (ret < 0) {
+		dev_err(&rt->chip->dev->dev,
+			"error initializing channels while setting samplerate %d.\n",
+			rates[rt->rate]);
+		return ret;
+	}
+
+	ctrl_rt->usb_streaming = true;
+	ret = ctrl_rt->update_streaming(ctrl_rt);
+	if (ret < 0) {
+		dev_err(&rt->chip->dev->dev,
+			"error starting streaming while setting samplerate %d.\n",
+			rates[rt->rate]);
+		return ret;
+	}
+
+	rt->in_n_analog = IN_N_CHANNELS;
+	rt->out_n_analog = OUT_N_CHANNELS;
+	rt->in_packet_size = rates_in_packet_size[rt->rate];
+	rt->out_packet_size = rates_out_packet_size[rt->rate];
+	return 0;
+}
+
+static struct pcm_substream *usb6fire_pcm_get_substream(
+		struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+
+	if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		return &rt->playback;
+	else if (alsa_sub->stream == SNDRV_PCM_STREAM_CAPTURE)
+		return &rt->capture;
+	dev_err(&rt->chip->dev->dev, "error getting pcm substream slot.\n");
+	return NULL;
+}
+
+/* call with stream_mutex locked */
+static void usb6fire_pcm_stream_stop(struct pcm_runtime *rt)
+{
+	int i;
+	struct control_runtime *ctrl_rt = rt->chip->control;
+
+	if (rt->stream_state != STREAM_DISABLED) {
+
+		rt->stream_state = STREAM_STOPPING;
+
+		for (i = 0; i < PCM_N_URBS; i++) {
+			usb_kill_urb(rt->in_urbs[i].instance);
+			usb_kill_urb(rt->out_urbs[i].instance);
+		}
+		ctrl_rt->usb_streaming = false;
+		ctrl_rt->update_streaming(ctrl_rt);
+		rt->stream_state = STREAM_DISABLED;
+	}
+}
+
+/* call with stream_mutex locked */
+static int usb6fire_pcm_stream_start(struct pcm_runtime *rt)
+{
+	int ret;
+	int i;
+	int k;
+	struct usb_iso_packet_descriptor *packet;
+
+	if (rt->stream_state == STREAM_DISABLED) {
+		/* submit our in urbs */
+		rt->stream_wait_cond = false;
+		rt->stream_state = STREAM_STARTING;
+		for (i = 0; i < PCM_N_URBS; i++) {
+			for (k = 0; k < PCM_N_PACKETS_PER_URB; k++) {
+				packet = &rt->in_urbs[i].instance->iso_frame_desc[k];
+				packet->offset = k * rt->in_packet_size;
+				packet->length = rt->in_packet_size;
+				packet->actual_length = 0;
+				packet->status = 0;
+			}
+			ret = usb_submit_urb(rt->in_urbs[i].instance,
+					GFP_ATOMIC);
+			if (ret) {
+				usb6fire_pcm_stream_stop(rt);
+				return ret;
+			}
+		}
+
+		/* wait for first out urb to return (sent in urb handler) */
+		wait_event_timeout(rt->stream_wait_queue, rt->stream_wait_cond,
+				HZ);
+		if (rt->stream_wait_cond)
+			rt->stream_state = STREAM_RUNNING;
+		else {
+			usb6fire_pcm_stream_stop(rt);
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+/* call with substream locked */
+static void usb6fire_pcm_capture(struct pcm_substream *sub, struct pcm_urb *urb)
+{
+	int i;
+	int frame;
+	int frame_count;
+	unsigned int total_length = 0;
+	struct pcm_runtime *rt = snd_pcm_substream_chip(sub->instance);
+	struct snd_pcm_runtime *alsa_rt = sub->instance->runtime;
+	struct usb_iso_packet_descriptor *isoc;
+	u32 *src = NULL;
+	u32 *dest = (u32 *) (alsa_rt->dma_area + sub->dma_off
+			* (alsa_rt->frame_bits >> 3));
+	u32 *dest_end = (u32 *) (alsa_rt->dma_area + alsa_rt->buffer_size
+			* (alsa_rt->frame_bits >> 3));
+	int bytes_per_frame = alsa_rt->channels << 2;
+
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
+		/* at least 4 header bytes for valid packet.
+		 * after that: 32 bits per sample for analog channels */
+		isoc = &urb->instance->iso_frame_desc[i];
+		if (isoc->actual_length > 4)
+			frame_count = (isoc->actual_length - 4)
+					/ (rt->in_n_analog << 2);
+		else
+			frame_count = 0;
+
+		if (alsa_rt->format == SNDRV_PCM_FORMAT_S24_LE)
+			src = (u32 *) (urb->buffer + total_length);
+		else if (alsa_rt->format == SNDRV_PCM_FORMAT_S32_LE)
+			src = (u32 *) (urb->buffer - 1 + total_length);
+		else
+			return;
+		src++; /* skip leading 4 bytes of every packet */
+		total_length += isoc->length;
+		for (frame = 0; frame < frame_count; frame++) {
+			memcpy(dest, src, bytes_per_frame);
+			dest += alsa_rt->channels;
+			src += rt->in_n_analog;
+			sub->dma_off++;
+			sub->period_off++;
+			if (dest == dest_end) {
+				sub->dma_off = 0;
+				dest = (u32 *) alsa_rt->dma_area;
+			}
+		}
+	}
+}
+
+/* call with substream locked */
+static void usb6fire_pcm_playback(struct pcm_substream *sub,
+		struct pcm_urb *urb)
+{
+	int i;
+	int frame;
+	int frame_count;
+	struct pcm_runtime *rt = snd_pcm_substream_chip(sub->instance);
+	struct snd_pcm_runtime *alsa_rt = sub->instance->runtime;
+	struct usb_iso_packet_descriptor *isoc;
+	u32 *src = (u32 *) (alsa_rt->dma_area + sub->dma_off
+			* (alsa_rt->frame_bits >> 3));
+	u32 *src_end = (u32 *) (alsa_rt->dma_area + alsa_rt->buffer_size
+			* (alsa_rt->frame_bits >> 3));
+	u32 *dest;
+	int bytes_per_frame = alsa_rt->channels << 2;
+
+	if (alsa_rt->format == SNDRV_PCM_FORMAT_S32_LE)
+		dest = (u32 *) (urb->buffer - 1);
+	else if (alsa_rt->format == SNDRV_PCM_FORMAT_S24_LE)
+		dest = (u32 *) (urb->buffer);
+	else {
+		dev_err(&rt->chip->dev->dev, "Unknown sample format.");
+		return;
+	}
+
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
+		/* at least 4 header bytes for valid packet.
+		 * after that: 32 bits per sample for analog channels */
+		isoc = &urb->instance->iso_frame_desc[i];
+		if (isoc->length > 4)
+			frame_count = (isoc->length - 4)
+					/ (rt->out_n_analog << 2);
+		else
+			frame_count = 0;
+		dest++; /* skip leading 4 bytes of every frame */
+		for (frame = 0; frame < frame_count; frame++) {
+			memcpy(dest, src, bytes_per_frame);
+			src += alsa_rt->channels;
+			dest += rt->out_n_analog;
+			sub->dma_off++;
+			sub->period_off++;
+			if (src == src_end) {
+				src = (u32 *) alsa_rt->dma_area;
+				sub->dma_off = 0;
+			}
+		}
+	}
+}
+
+static void usb6fire_pcm_in_urb_handler(struct urb *usb_urb)
+{
+	struct pcm_urb *in_urb = usb_urb->context;
+	struct pcm_urb *out_urb = in_urb->peer;
+	struct pcm_runtime *rt = in_urb->chip->pcm;
+	struct pcm_substream *sub;
+	struct usb_iso_packet_descriptor *isoc_out, *isoc_in;
+	bool period_elapsed;
+	int total_length = 0;
+	int frame_count;
+	int frame;
+	int channel;
+	int i;
+	u8 *dest;
+
+	if (usb_urb->status || rt->panic || rt->stream_state == STREAM_STOPPING)
+		return;
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
+		isoc_in = &in_urb->instance->iso_frame_desc[i];
+		if (isoc_in->status) {
+			rt->panic = true;
+			return;
+		}
+	}
+
+	if (rt->stream_state == STREAM_DISABLED) {
+		dev_err(&rt->chip->dev->dev,
+			"internal error: stream disabled in in-urb handler.\n");
+		return;
+	}
+
+	/* receive our capture data */
+	sub = &rt->capture;
+	period_elapsed = false;
+	scoped_guard(spinlock_irqsave, &sub->lock) {
+		if (sub->active) {
+			usb6fire_pcm_capture(sub, in_urb);
+			if (sub->period_off >= sub->instance->runtime->period_size) {
+				sub->period_off %= sub->instance->runtime->period_size;
+				period_elapsed = true;
+			}
+		}
+	}
+	if (period_elapsed)
+		snd_pcm_period_elapsed(sub->instance);
+
+	/* setup out urb structure */
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
+		unsigned int frames = 0;
+
+		isoc_out = &out_urb->instance->iso_frame_desc[i];
+		isoc_in = &in_urb->instance->iso_frame_desc[i];
+		if (isoc_in->actual_length > 4)
+			frames = (isoc_in->actual_length - 4)
+					/ (rt->in_n_analog << 2);
+		frames = min_t(unsigned int, frames,
+				       (rt->out_packet_size - 4)
+				       / (rt->out_n_analog << 2));
+
+		isoc_out->offset = total_length;
+		isoc_out->length = frames * (rt->out_n_analog << 2) + 4;
+		isoc_out->status = 0;
+		total_length += isoc_out->length;
+	}
+	memset(out_urb->buffer, 0, total_length);
+
+	/* now send our playback data (if a free out urb was found) */
+	sub = &rt->playback;
+	period_elapsed = false;
+	scoped_guard(spinlock_irqsave, &sub->lock) {
+		if (sub->active) {
+			usb6fire_pcm_playback(sub, out_urb);
+			if (sub->period_off >= sub->instance->runtime->period_size) {
+				sub->period_off %= sub->instance->runtime->period_size;
+				period_elapsed = true;
+			}
+		}
+	}
+	if (period_elapsed)
+		snd_pcm_period_elapsed(sub->instance);
+
+	/* setup the 4th byte of each sample (0x40 for analog channels) */
+	dest = out_urb->buffer;
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
+		isoc_out = &out_urb->instance->iso_frame_desc[i];
+		if (isoc_out->length >= 4) {
+			frame_count = (isoc_out->length - 4)
+					/ (rt->out_n_analog << 2);
+			*(dest++) = 0xaa;
+			*(dest++) = 0xaa;
+			*(dest++) = frame_count;
+			*(dest++) = 0x00;
+			for (frame = 0; frame < frame_count; frame++)
+				for (channel = 0;
+						channel < rt->out_n_analog;
+						channel++) {
+					dest += 3; /* skip sample data */
+					*(dest++) = 0x40;
+				}
+		}
+	}
+
+	usb_submit_urb(out_urb->instance, GFP_ATOMIC);
+	usb_submit_urb(in_urb->instance, GFP_ATOMIC);
+}
+
+static void usb6fire_pcm_out_urb_handler(struct urb *usb_urb)
+{
+	struct pcm_urb *urb = usb_urb->context;
+	struct pcm_runtime *rt = urb->chip->pcm;
+
+	if (rt->stream_state == STREAM_STARTING) {
+		rt->stream_wait_cond = true;
+		wake_up(&rt->stream_wait_queue);
+	}
+}
+
+static int usb6fire_pcm_open(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = NULL;
+	struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
+
+	if (rt->panic)
+		return -EPIPE;
+
+	guard(mutex)(&rt->stream_mutex);
+	alsa_rt->hw = pcm_hw;
+
+	if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		if (rt->rate < ARRAY_SIZE(rates))
+			alsa_rt->hw.rates = rates_alsaid[rt->rate];
+		alsa_rt->hw.channels_max = OUT_N_CHANNELS;
+		sub = &rt->playback;
+	} else if (alsa_sub->stream == SNDRV_PCM_STREAM_CAPTURE) {
+		if (rt->rate < ARRAY_SIZE(rates))
+			alsa_rt->hw.rates = rates_alsaid[rt->rate];
+		alsa_rt->hw.channels_max = IN_N_CHANNELS;
+		sub = &rt->capture;
+	}
+
+	if (!sub) {
+		dev_err(&rt->chip->dev->dev, "invalid stream type.\n");
+		return -EINVAL;
+	}
+
+	sub->instance = alsa_sub;
+	sub->active = false;
+	return 0;
+}
+
+static int usb6fire_pcm_close(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
+
+	if (rt->panic)
+		return 0;
+
+	guard(mutex)(&rt->stream_mutex);
+	if (sub) {
+		/* deactivate substream */
+		scoped_guard(spinlock_irqsave, &sub->lock) {
+			sub->instance = NULL;
+			sub->active = false;
+		}
+
+		/* all substreams closed? if so, stop streaming */
+		if (!rt->playback.instance && !rt->capture.instance) {
+			usb6fire_pcm_stream_stop(rt);
+			rt->rate = ARRAY_SIZE(rates);
+		}
+	}
+	return 0;
+}
+
+static int usb6fire_pcm_prepare(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
+	struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
+	int ret;
+
+	if (rt->panic)
+		return -EPIPE;
+	if (!sub)
+		return -ENODEV;
+
+	guard(mutex)(&rt->stream_mutex);
+	sub->dma_off = 0;
+	sub->period_off = 0;
+
+	if (rt->stream_state == STREAM_DISABLED) {
+		for (rt->rate = 0; rt->rate < ARRAY_SIZE(rates); rt->rate++)
+			if (alsa_rt->rate == rates[rt->rate])
+				break;
+		if (rt->rate == ARRAY_SIZE(rates)) {
+			dev_err(&rt->chip->dev->dev,
+				"invalid rate %d in prepare.\n",
+				alsa_rt->rate);
+			return -EINVAL;
+		}
+
+		ret = usb6fire_pcm_set_rate(rt);
+		if (ret)
+			return ret;
+		ret = usb6fire_pcm_stream_start(rt);
+		if (ret) {
+			dev_err(&rt->chip->dev->dev,
+				"could not start pcm stream.\n");
+			return ret;
+		}
+	}
+	return 0;
+}
+
+static int usb6fire_pcm_trigger(struct snd_pcm_substream *alsa_sub, int cmd)
+{
+	struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+
+	if (rt->panic)
+		return -EPIPE;
+	if (!sub)
+		return -ENODEV;
+
+	guard(spinlock_irqsave)(&sub->lock);
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		sub->active = true;
+		return 0;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		sub->active = false;
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static snd_pcm_uframes_t usb6fire_pcm_pointer(
+		struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	snd_pcm_uframes_t ret;
+
+	if (rt->panic || !sub)
+		return SNDRV_PCM_POS_XRUN;
+
+	guard(spinlock_irqsave)(&sub->lock);
+	ret = sub->dma_off;
+	return ret;
+}
+
+static const struct snd_pcm_ops pcm_ops = {
+	.open = usb6fire_pcm_open,
+	.close = usb6fire_pcm_close,
+	.prepare = usb6fire_pcm_prepare,
+	.trigger = usb6fire_pcm_trigger,
+	.pointer = usb6fire_pcm_pointer,
+};
+
+static int usb6fire_pcm_init_urb(struct pcm_urb *urb,
+				 struct sfire_chip *chip, bool in, int ep,
+				 void (*handler)(struct urb *))
+{
+	urb->chip = chip;
+	urb->instance = usb_alloc_urb(PCM_N_PACKETS_PER_URB, GFP_KERNEL);
+	if (!urb->instance)
+		return -ENOMEM;
+	urb->instance->transfer_buffer = urb->buffer;
+	urb->instance->transfer_buffer_length =
+			PCM_N_PACKETS_PER_URB * PCM_MAX_PACKET_SIZE;
+	urb->instance->dev = chip->dev;
+	urb->instance->pipe = in ? usb_rcvisocpipe(chip->dev, ep)
+			: usb_sndisocpipe(chip->dev, ep);
+	urb->instance->interval = 1;
+	urb->instance->complete = handler;
+	urb->instance->context = urb;
+	urb->instance->number_of_packets = PCM_N_PACKETS_PER_URB;
+	return 0;
+}
+
+static int usb6fire_pcm_buffers_init(struct pcm_runtime *rt)
+{
+	int i;
+
+	for (i = 0; i < PCM_N_URBS; i++) {
+		rt->out_urbs[i].buffer = kcalloc(PCM_MAX_PACKET_SIZE,
+						 PCM_N_PACKETS_PER_URB,
+						 GFP_KERNEL);
+		if (!rt->out_urbs[i].buffer)
+			return -ENOMEM;
+		rt->in_urbs[i].buffer = kcalloc(PCM_MAX_PACKET_SIZE,
+						PCM_N_PACKETS_PER_URB,
+						GFP_KERNEL);
+		if (!rt->in_urbs[i].buffer)
+			return -ENOMEM;
+	}
+	return 0;
+}
+
+static void usb6fire_pcm_free(struct pcm_runtime *rt)
+{
+	int i;
+
+	if (!rt)
+		return;
+
+	if (rt->chip)
+		rt->chip->pcm = NULL;
+
+	for (i = 0; i < PCM_N_URBS; i++) {
+		usb_free_urb(rt->out_urbs[i].instance);
+		kfree(rt->out_urbs[i].buffer);
+		usb_free_urb(rt->in_urbs[i].instance);
+		kfree(rt->in_urbs[i].buffer);
+	}
+	kfree(rt);
+}
+
+int usb6fire_pcm_init(struct sfire_chip *chip)
+{
+	int i;
+	int ret;
+	struct snd_pcm *pcm;
+	struct pcm_runtime *rt =
+			kzalloc_obj(struct pcm_runtime);
+
+	if (!rt)
+		return -ENOMEM;
+
+	ret = usb6fire_pcm_buffers_init(rt);
+	if (ret)
+		goto error;
+
+	rt->chip = chip;
+	rt->stream_state = STREAM_DISABLED;
+	rt->rate = ARRAY_SIZE(rates);
+	init_waitqueue_head(&rt->stream_wait_queue);
+	mutex_init(&rt->stream_mutex);
+
+	spin_lock_init(&rt->playback.lock);
+	spin_lock_init(&rt->capture.lock);
+
+	for (i = 0; i < PCM_N_URBS; i++) {
+		ret = usb6fire_pcm_init_urb(&rt->in_urbs[i], chip, true, IN_EP,
+					    usb6fire_pcm_in_urb_handler);
+		if (ret < 0)
+			goto error;
+		ret = usb6fire_pcm_init_urb(&rt->out_urbs[i], chip, false, OUT_EP,
+					    usb6fire_pcm_out_urb_handler);
+		if (ret < 0)
+			goto error;
+
+		rt->in_urbs[i].peer = &rt->out_urbs[i];
+		rt->out_urbs[i].peer = &rt->in_urbs[i];
+	}
+
+	ret = snd_pcm_new(chip->card, "DMX6FireUSB", 0, 1, 1, &pcm);
+	if (ret < 0) {
+		dev_err(&chip->dev->dev, "cannot create pcm instance.\n");
+		goto error;
+	}
+
+	pcm->private_data = rt;
+	strscpy(pcm->name, "DMX 6Fire USB");
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_ops);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &pcm_ops);
+	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
+
+	rt->instance = pcm;
+
+	chip->pcm = rt;
+	return 0;
+
+ error:
+	usb6fire_pcm_free(rt);
+	return ret;
+}
+
+void usb6fire_pcm_abort(struct sfire_chip *chip)
+{
+	struct pcm_runtime *rt = chip->pcm;
+	int i;
+
+	if (rt) {
+		rt->panic = true;
+
+		if (rt->playback.instance)
+			snd_pcm_stop_xrun(rt->playback.instance);
+
+		if (rt->capture.instance)
+			snd_pcm_stop_xrun(rt->capture.instance);
+
+		for (i = 0; i < PCM_N_URBS; i++) {
+			usb_poison_urb(rt->in_urbs[i].instance);
+			usb_poison_urb(rt->out_urbs[i].instance);
+		}
+
+	}
+}
+
+void usb6fire_pcm_destroy(struct sfire_chip *chip)
+{
+	usb6fire_pcm_free(chip->pcm);
+}
diff --git a/sound/usb/6fire/pcm.h b/sound/usb/6fire/pcm.h
new file mode 100644
index 000000000..b586fe220
--- /dev/null
+++ b/sound/usb/6fire/pcm.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Copyright:	(C) Torsten Schenk
+ */
+
+#ifndef USB6FIRE_PCM_H
+#define USB6FIRE_PCM_H
+
+#include <sound/pcm.h>
+#include <linux/mutex.h>
+
+#include "common.h"
+
+enum /* settings for pcm */
+{
+	/* maximum of EP_W_MAX_PACKET_SIZE[] (see firmware.c) */
+	PCM_N_URBS = 16, PCM_N_PACKETS_PER_URB = 8, PCM_MAX_PACKET_SIZE = 604
+};
+
+struct pcm_urb {
+	struct sfire_chip *chip;
+
+	struct urb *instance;
+	u8 *buffer;
+
+	struct pcm_urb *peer;
+};
+
+struct pcm_substream {
+	spinlock_t lock;
+	struct snd_pcm_substream *instance;
+
+	bool active;
+
+	snd_pcm_uframes_t dma_off; /* current position in alsa dma_area */
+	snd_pcm_uframes_t period_off; /* current position in current period */
+};
+
+struct pcm_runtime {
+	struct sfire_chip *chip;
+	struct snd_pcm *instance;
+
+	struct pcm_substream playback;
+	struct pcm_substream capture;
+	bool panic; /* if set driver won't do anymore pcm on device */
+
+	struct pcm_urb in_urbs[PCM_N_URBS];
+	struct pcm_urb out_urbs[PCM_N_URBS];
+	int in_packet_size;
+	int out_packet_size;
+	int in_n_analog; /* number of analog channels soundcard sends */
+	int out_n_analog; /* number of analog channels soundcard receives */
+
+	struct mutex stream_mutex;
+	u8 stream_state; /* one of STREAM_XXX (pcm.c) */
+	u8 rate; /* one of PCM_RATE_XXX */
+	wait_queue_head_t stream_wait_queue;
+	bool stream_wait_cond;
+};
+
+int usb6fire_pcm_init(struct sfire_chip *chip);
+void usb6fire_pcm_abort(struct sfire_chip *chip);
+void usb6fire_pcm_destroy(struct sfire_chip *chip);
+#endif /* USB6FIRE_PCM_H */
diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
new file mode 100644
index 000000000..b4588915e
--- /dev/null
+++ b/sound/usb/Kconfig
@@ -0,0 +1,210 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# ALSA USB drivers
+
+menuconfig SND_USB
+	bool "USB sound devices"
+	depends on USB
+	default y
+	help
+	  Support for sound devices connected via the USB bus.
+
+if SND_USB && USB
+
+config SND_USB_AUDIO
+	tristate "USB Audio/MIDI driver"
+	select SND_HWDEP
+	select SND_RAWMIDI
+	select SND_PCM
+	select SND_UMP if SND_USB_AUDIO_MIDI_V2
+	select BITREVERSE
+	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT=y || MEDIA_SUPPORT=SND_USB_AUDIO)
+	help
+	  Say Y here to include support for USB audio and USB MIDI
+	  devices.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-usb-audio.
+
+config SND_USB_AUDIO_MIDI_V2
+	bool "MIDI 2.0 support by USB Audio driver"
+	depends on SND_USB_AUDIO
+	help
+	  Say Y here to include the support for MIDI 2.0 by USB Audio driver.
+	  When the config is set, the driver tries to probe MIDI 2.0 interface
+	  at first, then falls back to MIDI 1.0 interface as default.
+	  The MIDI 2.0 support can be disabled dynamically via midi2_enable
+	  module option, too.
+
+config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
+	bool
+
+config SND_USB_UA101
+	tristate "Edirol UA-101/UA-1000 driver"
+	select SND_PCM
+	select SND_RAWMIDI
+	help
+	  Say Y here to include support for the Edirol UA-101 and UA-1000
+	  audio/MIDI interfaces.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-ua101.
+
+config SND_USB_USX2Y
+	tristate "Tascam US-122, US-224 and US-428 USB driver"
+	depends on X86 || PPC || ALPHA
+	select SND_HWDEP
+	select SND_RAWMIDI
+	select SND_PCM
+	help
+	  Say Y here to include support for Tascam USB Audio/MIDI
+	  interfaces or controllers US-122, US-224 and US-428.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-usb-usx2y.
+
+config SND_USB_CAIAQ
+	tristate "Native Instruments USB audio devices"
+	select SND_HWDEP
+	select SND_RAWMIDI
+	select SND_PCM
+	help
+	   Say Y here to include support for caiaq USB audio interfaces,
+	   namely:
+
+	    * Native Instruments RigKontrol2
+	    * Native Instruments RigKontrol3
+	    * Native Instruments Kore Controller
+	    * Native Instruments Kore Controller 2
+	    * Native Instruments Audio Kontrol 1
+	    * Native Instruments Audio 2 DJ
+	    * Native Instruments Audio 4 DJ
+	    * Native Instruments Audio 8 DJ
+	    * Native Instruments Traktor Audio 2
+	    * Native Instruments Guitar Rig Session I/O
+	    * Native Instruments Guitar Rig mobile
+	    * Native Instruments Traktor Kontrol X1
+	    * Native Instruments Traktor Kontrol S4
+	    * Native Instruments Maschine Controller
+
+	   To compile this driver as a module, choose M here: the module
+	   will be called snd-usb-caiaq.
+
+config SND_USB_CAIAQ_INPUT
+	bool "enable input device for controllers"
+	depends on SND_USB_CAIAQ
+	depends on INPUT=y || INPUT=SND_USB_CAIAQ
+	help
+	  Say Y here to support input controllers like buttons, knobs,
+	  alpha dials and analog pedals on the following products:
+
+	   * Native Instruments RigKontrol2
+	   * Native Instruments RigKontrol3
+	   * Native Instruments Kore Controller
+	   * Native Instruments Kore Controller 2
+	   * Native Instruments Audio Kontrol 1
+	   * Native Instruments Traktor Kontrol S4
+	   * Native Instruments Maschine Controller
+
+config SND_USB_US122L
+	tristate "Tascam US-122L USB driver"
+	depends on X86 || COMPILE_TEST
+	select SND_HWDEP
+	select SND_RAWMIDI
+	help
+	  Say Y here to include support for Tascam US-122L USB Audio/MIDI
+	  interfaces.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-usb-us122l.
+
+config SND_USB_US144MKII
+	tristate "Tascam US-144MKII USB driver"
+	depends on X86 || COMPILE_TEST
+	select SND_RAWMIDI
+	select SND_PCM
+	help
+	  Say Y here to include support for Tascam US-144MKII USB Audio/MIDI
+	  interface.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-usb-us144mkii.
+
+config SND_USB_6FIRE
+	tristate "TerraTec DMX 6Fire USB"
+	select FW_LOADER
+	select BITREVERSE
+	select SND_RAWMIDI
+	select SND_PCM
+	select SND_VMASTER
+	help
+	  Say Y here to include support for TerraTec 6fire DMX USB interface.
+
+	  You will need firmware files in order to be able to use the device
+	  after it has been coldstarted. An install script for the firmware
+	  and further help can be found at
+	  http://sixfireusb.sourceforge.net
+
+config SND_USB_HIFACE
+	tristate "M2Tech hiFace USB-SPDIF driver"
+	select SND_PCM
+	help
+	  Select this option to include support for M2Tech hiFace USB-SPDIF
+	  interface.
+
+	  This driver supports the original M2Tech hiFace and some other
+	  compatible devices. The supported products are:
+
+	    * M2Tech Young
+	    * M2Tech hiFace
+	    * M2Tech North Star
+	    * M2Tech W4S Young
+	    * M2Tech Corrson
+	    * M2Tech AUDIA
+	    * M2Tech SL Audio
+	    * M2Tech Empirical
+	    * M2Tech Rockna
+	    * M2Tech Pathos
+	    * M2Tech Metronome
+	    * M2Tech CAD
+	    * M2Tech Audio Esclusive
+	    * M2Tech Rotel
+	    * M2Tech Eeaudio
+	    * The Chord Company CHORD
+	    * AVA Group A/S Vitus
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-usb-hiface.
+
+config SND_BCD2000
+	tristate "Behringer BCD2000 MIDI driver"
+	select SND_RAWMIDI
+	help
+	  Say Y here to include MIDI support for the Behringer BCD2000 DJ
+	  controller.
+
+	  Audio support is still work-in-progress at
+	  https://github.com/anyc/snd-usb-bcd2000
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-bcd2000.
+
+config SND_USB_AUDIO_QMI
+	tristate "Qualcomm Audio Offload driver"
+	depends on QCOM_QMI_HELPERS && SND_USB_AUDIO && SND_SOC_USB
+	depends on USB_XHCI_HCD && USB_XHCI_SIDEBAND
+	select AUXILIARY_BUS
+	help
+	  Say Y here to enable the Qualcomm USB audio offloading feature.
+
+	  This module sets up the required QMI stream enable/disable
+	  responses to requests generated by the audio DSP.  It passes the
+	  USB transfer resource references, so that the audio DSP can issue
+	  USB transfers to the host controller.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-usb-audio-qmi.
+
+source "sound/usb/line6/Kconfig"
+
+endif	# SND_USB
+
diff --git a/sound/usb/Makefile b/sound/usb/Makefile
new file mode 100644
index 000000000..e62794a87
--- /dev/null
+++ b/sound/usb/Makefile
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for ALSA
+#
+
+snd-usb-audio-y := 	card.o \
+			clock.o \
+			endpoint.o \
+			fcp.o \
+			format.o \
+			helper.o \
+			implicit.o \
+			mixer.o \
+			mixer_quirks.o \
+			mixer_scarlett.o \
+			mixer_scarlett2.o \
+			mixer_us16x08.o \
+			mixer_s1810c.o \
+			pcm.o \
+			power.o \
+			proc.o \
+			quirks.o \
+			stream.o \
+			validate.o
+
+snd-usb-audio-$(CONFIG_SND_USB_AUDIO_MIDI_V2) += midi2.o
+snd-usb-audio-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.o
+
+snd-usbmidi-lib-y := midi.o
+
+# Toplevel Module Dependency
+obj-$(CONFIG_SND_USB_AUDIO) += snd-usb-audio.o snd-usbmidi-lib.o
+
+obj-$(CONFIG_SND_USB_UA101) += snd-usbmidi-lib.o
+obj-$(CONFIG_SND_USB_USX2Y) += snd-usbmidi-lib.o
+obj-$(CONFIG_SND_USB_US122L) += snd-usbmidi-lib.o
+
+obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/ bcd2000/ qcom/
+obj-$(CONFIG_SND_USB_LINE6)	+= line6/
diff --git a/sound/usb/bcd2000/Makefile b/sound/usb/bcd2000/Makefile
new file mode 100644
index 000000000..e2d916e24
--- /dev/null
+++ b/sound/usb/bcd2000/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+snd-bcd2000-y := bcd2000.o
+
+obj-$(CONFIG_SND_BCD2000) += snd-bcd2000.o
diff --git a/sound/usb/bcd2000/bcd2000.c b/sound/usb/bcd2000/bcd2000.c
new file mode 100644
index 000000000..2bd49bf82
--- /dev/null
+++ b/sound/usb/bcd2000/bcd2000.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Behringer BCD2000 driver
+ *
+ *   Copyright (C) 2014 Mario Kicherer (dev@kicherer.org)
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/bitmap.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/rawmidi.h>
+
+#define PREFIX "snd-bcd2000: "
+#define BUFSIZE 64
+
+static const struct usb_device_id id_table[] = {
+	{ USB_DEVICE(0x1397, 0x00bd) },
+	{ },
+};
+
+static const unsigned char device_cmd_prefix[] = {0x03, 0x00};
+
+static const unsigned char bcd2000_init_sequence[] = {
+	0x07, 0x00, 0x00, 0x00, 0x78, 0x48, 0x1c, 0x81,
+	0xc4, 0x00, 0x00, 0x00, 0x5e, 0x53, 0x4a, 0xf7,
+	0x18, 0xfa, 0x11, 0xff, 0x6c, 0xf3, 0x90, 0xff,
+	0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
+	0x18, 0xfa, 0x11, 0xff, 0x14, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0xf2, 0x34, 0x4a, 0xf7,
+	0x18, 0xfa, 0x11, 0xff
+};
+
+struct bcd2000 {
+	struct usb_device *dev;
+	struct snd_card *card;
+	struct usb_interface *intf;
+	int card_index;
+
+	spinlock_t midi_lock;
+	int midi_out_active;
+	struct snd_rawmidi *rmidi;
+	struct snd_rawmidi_substream *midi_receive_substream;
+	struct snd_rawmidi_substream *midi_out_substream;
+
+	unsigned char midi_in_buf[BUFSIZE];
+	unsigned char midi_out_buf[BUFSIZE];
+
+	struct urb *midi_out_urb;
+	struct urb *midi_in_urb;
+
+	struct usb_anchor anchor;
+};
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
+
+static DEFINE_MUTEX(devices_mutex);
+static DECLARE_BITMAP(devices_used, SNDRV_CARDS);
+static struct usb_driver bcd2000_driver;
+
+#ifdef CONFIG_SND_DEBUG
+static void bcd2000_dump_buffer(const char *prefix, const char *buf, int len)
+{
+	print_hex_dump(KERN_DEBUG, prefix,
+			DUMP_PREFIX_NONE, 16, 1,
+			buf, len, false);
+}
+#else
+static void bcd2000_dump_buffer(const char *prefix, const char *buf, int len) {}
+#endif
+
+static int bcd2000_midi_input_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int bcd2000_midi_input_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+/* (de)register midi substream from client */
+static void bcd2000_midi_input_trigger(struct snd_rawmidi_substream *substream,
+						int up)
+{
+	struct bcd2000 *bcd2k = substream->rmidi->private_data;
+
+	guard(spinlock_irqsave)(&bcd2k->midi_lock);
+	bcd2k->midi_receive_substream = up ? substream : NULL;
+}
+
+static void bcd2000_midi_handle_input(struct bcd2000 *bcd2k,
+				const unsigned char *buf, unsigned int buf_len)
+{
+	unsigned int payload_length, tocopy;
+	struct snd_rawmidi_substream *midi_receive_substream;
+
+	midi_receive_substream = READ_ONCE(bcd2k->midi_receive_substream);
+	if (!midi_receive_substream)
+		return;
+
+	bcd2000_dump_buffer(PREFIX "received from device: ", buf, buf_len);
+
+	if (buf_len < 2)
+		return;
+
+	payload_length = buf[0];
+
+	/* ignore packets without payload */
+	if (payload_length == 0)
+		return;
+
+	tocopy = min(payload_length, buf_len-1);
+
+	bcd2000_dump_buffer(PREFIX "sending to userspace: ",
+					&buf[1], tocopy);
+
+	snd_rawmidi_receive(midi_receive_substream,
+					&buf[1], tocopy);
+}
+
+static void bcd2000_midi_send(struct bcd2000 *bcd2k)
+{
+	int len, ret;
+	struct snd_rawmidi_substream *midi_out_substream;
+
+	BUILD_BUG_ON(sizeof(device_cmd_prefix) >= BUFSIZE);
+
+	midi_out_substream = READ_ONCE(bcd2k->midi_out_substream);
+	if (!midi_out_substream)
+		return;
+
+	if (!bcd2k->midi_out_urb)
+		return;
+
+	/* copy command prefix bytes */
+	memcpy(bcd2k->midi_out_buf, device_cmd_prefix,
+		sizeof(device_cmd_prefix));
+
+	/*
+	 * get MIDI packet and leave space for command prefix
+	 * and payload length
+	 */
+	len = snd_rawmidi_transmit(midi_out_substream,
+				bcd2k->midi_out_buf + 3, BUFSIZE - 3);
+
+	if (len < 0)
+		dev_err(&bcd2k->dev->dev, "%s: snd_rawmidi_transmit error %d\n",
+				__func__, len);
+
+	if (len <= 0)
+		return;
+
+	/* set payload length */
+	bcd2k->midi_out_buf[2] = len;
+	bcd2k->midi_out_urb->transfer_buffer_length = BUFSIZE;
+
+	bcd2000_dump_buffer(PREFIX "sending to device: ",
+			bcd2k->midi_out_buf, len+3);
+
+	/* send packet to the BCD2000 */
+	ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_ATOMIC);
+	if (ret < 0)
+		dev_err(&bcd2k->dev->dev, PREFIX
+			"%s (%p): usb_submit_urb() failed, ret=%d, len=%d\n",
+			__func__, midi_out_substream, ret, len);
+	else
+		bcd2k->midi_out_active = 1;
+}
+
+static int bcd2000_midi_output_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int bcd2000_midi_output_close(struct snd_rawmidi_substream *substream)
+{
+	struct bcd2000 *bcd2k = substream->rmidi->private_data;
+
+	if (bcd2k->midi_out_active && bcd2k->midi_out_urb) {
+		usb_kill_urb(bcd2k->midi_out_urb);
+		bcd2k->midi_out_active = 0;
+	}
+
+	return 0;
+}
+
+/* (de)register midi substream from client */
+static void bcd2000_midi_output_trigger(struct snd_rawmidi_substream *substream,
+						int up)
+{
+	struct bcd2000 *bcd2k = substream->rmidi->private_data;
+
+	guard(spinlock_irqsave)(&bcd2k->midi_lock);
+
+	if (up) {
+		bcd2k->midi_out_substream = substream;
+		/* check if there is data userspace wants to send */
+		if (!bcd2k->midi_out_active)
+			bcd2000_midi_send(bcd2k);
+	} else {
+		bcd2k->midi_out_substream = NULL;
+	}
+}
+
+static void bcd2000_output_complete(struct urb *urb)
+{
+	struct bcd2000 *bcd2k = urb->context;
+
+	bcd2k->midi_out_active = 0;
+
+	if (urb->status)
+		dev_warn(&urb->dev->dev,
+			PREFIX "output urb->status: %d\n", urb->status);
+
+	if (urb->status == -ESHUTDOWN)
+		return;
+
+	/* check if there is more data userspace wants to send */
+	guard(spinlock_irqsave)(&bcd2k->midi_lock);
+	bcd2000_midi_send(bcd2k);
+}
+
+static void bcd2000_input_complete(struct urb *urb)
+{
+	int ret;
+	struct bcd2000 *bcd2k = urb->context;
+
+	if (urb->status)
+		dev_warn(&urb->dev->dev,
+			PREFIX "input urb->status: %i\n", urb->status);
+
+	if (!bcd2k || urb->status == -ESHUTDOWN)
+		return;
+
+	guard(spinlock_irqsave)(&bcd2k->midi_lock);
+
+	if (urb->actual_length > 0)
+		bcd2000_midi_handle_input(bcd2k, urb->transfer_buffer,
+					urb->actual_length);
+
+	/* return URB to device */
+	ret = usb_submit_urb(bcd2k->midi_in_urb, GFP_ATOMIC);
+	if (ret < 0)
+		dev_err(&bcd2k->dev->dev, PREFIX
+			"%s: usb_submit_urb() failed, ret=%d\n",
+			__func__, ret);
+}
+
+static const struct snd_rawmidi_ops bcd2000_midi_output = {
+	.open =    bcd2000_midi_output_open,
+	.close =   bcd2000_midi_output_close,
+	.trigger = bcd2000_midi_output_trigger,
+};
+
+static const struct snd_rawmidi_ops bcd2000_midi_input = {
+	.open =    bcd2000_midi_input_open,
+	.close =   bcd2000_midi_input_close,
+	.trigger = bcd2000_midi_input_trigger,
+};
+
+static void bcd2000_init_device(struct bcd2000 *bcd2k)
+{
+	int ret;
+
+	init_usb_anchor(&bcd2k->anchor);
+	usb_anchor_urb(bcd2k->midi_out_urb, &bcd2k->anchor);
+	usb_anchor_urb(bcd2k->midi_in_urb, &bcd2k->anchor);
+
+	/* copy init sequence into buffer */
+	memcpy(bcd2k->midi_out_buf, bcd2000_init_sequence, 52);
+	bcd2k->midi_out_urb->transfer_buffer_length = 52;
+
+	/* submit sequence */
+	ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_KERNEL);
+	if (ret < 0)
+		dev_err(&bcd2k->dev->dev, PREFIX
+			"%s: usb_submit_urb() out failed, ret=%d: ",
+			__func__, ret);
+	else
+		bcd2k->midi_out_active = 1;
+
+	/* pass URB to device to enable button and controller events */
+	ret = usb_submit_urb(bcd2k->midi_in_urb, GFP_KERNEL);
+	if (ret < 0)
+		dev_err(&bcd2k->dev->dev, PREFIX
+			"%s: usb_submit_urb() in failed, ret=%d: ",
+			__func__, ret);
+
+	/* ensure initialization is finished */
+	usb_wait_anchor_empty_timeout(&bcd2k->anchor, 1000);
+}
+
+static int bcd2000_init_midi(struct bcd2000 *bcd2k)
+{
+	int ret;
+	struct snd_rawmidi *rmidi;
+
+	ret = snd_rawmidi_new(bcd2k->card, bcd2k->card->shortname, 0,
+					1, /* output */
+					1, /* input */
+					&rmidi);
+
+	if (ret < 0)
+		return ret;
+
+	strscpy(rmidi->name, bcd2k->card->shortname, sizeof(rmidi->name));
+
+	rmidi->info_flags = SNDRV_RAWMIDI_INFO_DUPLEX;
+	rmidi->private_data = bcd2k;
+
+	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT;
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+					&bcd2000_midi_output);
+
+	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+					&bcd2000_midi_input);
+
+	bcd2k->rmidi = rmidi;
+
+	bcd2k->midi_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	bcd2k->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+
+	if (!bcd2k->midi_in_urb || !bcd2k->midi_out_urb) {
+		dev_err(&bcd2k->dev->dev, PREFIX "usb_alloc_urb failed\n");
+		return -ENOMEM;
+	}
+
+	usb_fill_int_urb(bcd2k->midi_in_urb, bcd2k->dev,
+				usb_rcvintpipe(bcd2k->dev, 0x81),
+				bcd2k->midi_in_buf, BUFSIZE,
+				bcd2000_input_complete, bcd2k, 1);
+
+	usb_fill_int_urb(bcd2k->midi_out_urb, bcd2k->dev,
+				usb_sndintpipe(bcd2k->dev, 0x1),
+				bcd2k->midi_out_buf, BUFSIZE,
+				bcd2000_output_complete, bcd2k, 1);
+
+	/* sanity checks of EPs before actually submitting */
+	if (usb_urb_ep_type_check(bcd2k->midi_in_urb) ||
+	    usb_urb_ep_type_check(bcd2k->midi_out_urb)) {
+		dev_err(&bcd2k->dev->dev, "invalid MIDI EP\n");
+		return -EINVAL;
+	}
+
+	bcd2000_init_device(bcd2k);
+
+	return 0;
+}
+
+static void bcd2000_midi_free(struct bcd2000 *bcd2k,
+			      struct urb **urb_p)
+{
+	struct urb *urb = *urb_p;
+
+	if (!urb)
+		return;
+
+	usb_poison_urb(urb);
+	scoped_guard(spinlock_irq, &bcd2k->midi_lock)
+		*urb_p = NULL;
+
+	usb_free_urb(urb);
+}
+
+static void bcd2000_free_usb_related_resources(struct bcd2000 *bcd2k,
+						struct usb_interface *interface)
+{
+	bcd2000_midi_free(bcd2k, &bcd2k->midi_out_urb);
+	bcd2000_midi_free(bcd2k, &bcd2k->midi_in_urb);
+
+	if (bcd2k->intf) {
+		usb_set_intfdata(bcd2k->intf, NULL);
+		bcd2k->intf = NULL;
+	}
+}
+
+static int bcd2000_probe(struct usb_interface *interface,
+				const struct usb_device_id *usb_id)
+{
+	struct snd_card *card;
+	struct bcd2000 *bcd2k;
+	unsigned int card_index;
+	char usb_path[32];
+	int err;
+
+	guard(mutex)(&devices_mutex);
+
+	for (card_index = 0; card_index < SNDRV_CARDS; ++card_index)
+		if (!test_bit(card_index, devices_used))
+			break;
+
+	if (card_index >= SNDRV_CARDS)
+		return -ENOENT;
+
+	err = snd_card_new(&interface->dev, index[card_index], id[card_index],
+			THIS_MODULE, sizeof(*bcd2k), &card);
+	if (err < 0)
+		return err;
+
+	bcd2k = card->private_data;
+	bcd2k->dev = interface_to_usbdev(interface);
+	bcd2k->card = card;
+	bcd2k->card_index = card_index;
+	bcd2k->intf = interface;
+	spin_lock_init(&bcd2k->midi_lock);
+
+	snd_card_set_dev(card, &interface->dev);
+
+	strscpy(card->driver, "snd-bcd2000", sizeof(card->driver));
+	strscpy(card->shortname, "BCD2000", sizeof(card->shortname));
+	usb_make_path(bcd2k->dev, usb_path, sizeof(usb_path));
+	snprintf(bcd2k->card->longname, sizeof(bcd2k->card->longname),
+		    "Behringer BCD2000 at %s",
+			usb_path);
+
+	err = bcd2000_init_midi(bcd2k);
+	if (err < 0)
+		goto probe_error;
+
+	err = snd_card_register(card);
+	if (err < 0)
+		goto probe_error;
+
+	usb_set_intfdata(interface, bcd2k);
+	set_bit(card_index, devices_used);
+
+	return 0;
+
+probe_error:
+	dev_info(&bcd2k->dev->dev, PREFIX "error during probing");
+	bcd2000_free_usb_related_resources(bcd2k, interface);
+	snd_card_free(card);
+	return err;
+}
+
+static void bcd2000_disconnect(struct usb_interface *interface)
+{
+	struct bcd2000 *bcd2k = usb_get_intfdata(interface);
+
+	if (!bcd2k)
+		return;
+
+	guard(mutex)(&devices_mutex);
+
+	/* make sure that userspace cannot create new requests */
+	snd_card_disconnect(bcd2k->card);
+
+	bcd2000_free_usb_related_resources(bcd2k, interface);
+
+	clear_bit(bcd2k->card_index, devices_used);
+
+	snd_card_free_when_closed(bcd2k->card);
+}
+
+static struct usb_driver bcd2000_driver = {
+	.name =		"snd-bcd2000",
+	.probe =	bcd2000_probe,
+	.disconnect =	bcd2000_disconnect,
+	.id_table =	id_table,
+};
+
+module_usb_driver(bcd2000_driver);
+
+MODULE_DEVICE_TABLE(usb, id_table);
+MODULE_AUTHOR("Mario Kicherer, dev@kicherer.org");
+MODULE_DESCRIPTION("Behringer BCD2000 driver");
+MODULE_LICENSE("GPL");
diff --git a/sound/usb/caiaq/Makefile b/sound/usb/caiaq/Makefile
new file mode 100644
index 000000000..9a99c17a2
--- /dev/null
+++ b/sound/usb/caiaq/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+snd-usb-caiaq-y := device.o audio.o midi.o control.o
+snd-usb-caiaq-$(CONFIG_SND_USB_CAIAQ_INPUT) += input.o
+
+obj-$(CONFIG_SND_USB_CAIAQ) += snd-usb-caiaq.o
diff --git a/sound/usb/caiaq/audio.c b/sound/usb/caiaq/audio.c
new file mode 100644
index 000000000..bb6280aa3
--- /dev/null
+++ b/sound/usb/caiaq/audio.c
@@ -0,0 +1,863 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (c) 2006-2008 Daniel Mack, Karsten Wiese
+*/
+
+#include <linux/device.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/usb.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+
+#include "device.h"
+#include "audio.h"
+
+#define N_URBS			32
+#define CLOCK_DRIFT_TOLERANCE	5
+#define FRAMES_PER_URB		8
+#define BYTES_PER_FRAME		512
+#define CHANNELS_PER_STREAM	2
+#define BYTES_PER_SAMPLE	3
+#define BYTES_PER_SAMPLE_USB	4
+#define MAX_BUFFER_SIZE		(128*1024)
+#define MAX_ENDPOINT_SIZE	512
+
+#define ENDPOINT_CAPTURE	2
+#define ENDPOINT_PLAYBACK	6
+
+#define MAKE_CHECKBYTE(cdev,stream,i) \
+	(stream << 1) | (~(i / (cdev->n_streams * BYTES_PER_SAMPLE_USB)) & 1)
+
+static const struct snd_pcm_hardware snd_usb_caiaq_pcm_hardware = {
+	.info 		= (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
+			   SNDRV_PCM_INFO_BLOCK_TRANSFER),
+	.formats 	= SNDRV_PCM_FMTBIT_S24_3BE,
+	.rates 		= (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |
+			   SNDRV_PCM_RATE_96000),
+	.rate_min	= 44100,
+	.rate_max	= 0, /* will overwrite later */
+	.channels_min	= CHANNELS_PER_STREAM,
+	.channels_max	= CHANNELS_PER_STREAM,
+	.buffer_bytes_max = MAX_BUFFER_SIZE,
+	.period_bytes_min = 128,
+	.period_bytes_max = MAX_BUFFER_SIZE,
+	.periods_min	= 1,
+	.periods_max	= 1024,
+};
+
+static void
+activate_substream(struct snd_usb_caiaqdev *cdev,
+	           struct snd_pcm_substream *sub)
+{
+	guard(spinlock)(&cdev->spinlock);
+
+	if (sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		cdev->sub_playback[sub->number] = sub;
+	else
+		cdev->sub_capture[sub->number] = sub;
+}
+
+static void
+deactivate_substream(struct snd_usb_caiaqdev *cdev,
+		     struct snd_pcm_substream *sub)
+{
+	guard(spinlock_irqsave)(&cdev->spinlock);
+
+	if (sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		cdev->sub_playback[sub->number] = NULL;
+	else
+		cdev->sub_capture[sub->number] = NULL;
+}
+
+static int
+all_substreams_zero(struct snd_pcm_substream **subs)
+{
+	int i;
+	for (i = 0; i < MAX_STREAMS; i++)
+		if (subs[i] != NULL)
+			return 0;
+	return 1;
+}
+
+static int stream_start(struct snd_usb_caiaqdev *cdev)
+{
+	int i, ret;
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	dev_dbg(dev, "%s(%p)\n", __func__, cdev);
+
+	if (cdev->streaming)
+		return -EINVAL;
+
+	memset(cdev->sub_playback, 0, sizeof(cdev->sub_playback));
+	memset(cdev->sub_capture, 0, sizeof(cdev->sub_capture));
+	cdev->input_panic = 0;
+	cdev->output_panic = 0;
+	cdev->first_packet = 4;
+	cdev->streaming = 1;
+	cdev->warned = 0;
+
+	for (i = 0; i < N_URBS; i++) {
+		ret = usb_submit_urb(cdev->data_urbs_in[i], GFP_ATOMIC);
+		if (ret) {
+			dev_err(dev, "unable to trigger read #%d! (ret %d)\n",
+				i, ret);
+			cdev->streaming = 0;
+			return -EPIPE;
+		}
+	}
+
+	return 0;
+}
+
+static void stream_stop(struct snd_usb_caiaqdev *cdev)
+{
+	int i;
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	dev_dbg(dev, "%s(%p)\n", __func__, cdev);
+	if (!cdev->streaming)
+		return;
+
+	cdev->streaming = 0;
+
+	for (i = 0; i < N_URBS; i++) {
+		usb_kill_urb(cdev->data_urbs_in[i]);
+
+		if (test_bit(i, &cdev->outurb_active_mask))
+			usb_kill_urb(cdev->data_urbs_out[i]);
+	}
+
+	cdev->outurb_active_mask = 0;
+}
+
+static int snd_usb_caiaq_substream_open(struct snd_pcm_substream *substream)
+{
+	struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(substream);
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	dev_dbg(dev, "%s(%p)\n", __func__, substream);
+	substream->runtime->hw = cdev->pcm_info;
+	snd_pcm_limit_hw_rates(substream->runtime);
+
+	return 0;
+}
+
+static int snd_usb_caiaq_substream_close(struct snd_pcm_substream *substream)
+{
+	struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(substream);
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	dev_dbg(dev, "%s(%p)\n", __func__, substream);
+	if (all_substreams_zero(cdev->sub_playback) &&
+	    all_substreams_zero(cdev->sub_capture)) {
+		/* when the last client has stopped streaming,
+		 * all sample rates are allowed again */
+		stream_stop(cdev);
+		cdev->pcm_info.rates = cdev->samplerates;
+	}
+
+	return 0;
+}
+
+static int snd_usb_caiaq_pcm_hw_free(struct snd_pcm_substream *sub)
+{
+	struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(sub);
+	deactivate_substream(cdev, sub);
+	return 0;
+}
+
+static int snd_usb_caiaq_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	int bytes_per_sample, bpp, ret;
+	int index = substream->number;
+	struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	dev_dbg(dev, "%s(%p)\n", __func__, substream);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		int out_pos;
+
+		switch (cdev->spec.data_alignment) {
+		case 0:
+		case 2:
+			out_pos = BYTES_PER_SAMPLE + 1;
+			break;
+		case 3:
+		default:
+			out_pos = 0;
+			break;
+		}
+
+		cdev->period_out_count[index] = out_pos;
+		cdev->audio_out_buf_pos[index] = out_pos;
+	} else {
+		int in_pos;
+
+		switch (cdev->spec.data_alignment) {
+		case 0:
+			in_pos = BYTES_PER_SAMPLE + 2;
+			break;
+		case 2:
+			in_pos = BYTES_PER_SAMPLE;
+			break;
+		case 3:
+		default:
+			in_pos = 0;
+			break;
+		}
+
+		cdev->period_in_count[index] = in_pos;
+		cdev->audio_in_buf_pos[index] = in_pos;
+	}
+
+	if (cdev->streaming)
+		return 0;
+
+	/* the first client that opens a stream defines the sample rate
+	 * setting for all subsequent calls, until the last client closed. */
+	cdev->pcm_info.rates = snd_pcm_rate_to_rate_bit(runtime->rate);
+	snd_pcm_limit_hw_rates(runtime);
+
+	bytes_per_sample = BYTES_PER_SAMPLE;
+	if (cdev->spec.data_alignment >= 2)
+		bytes_per_sample++;
+
+	bpp = ((runtime->rate / 8000) + CLOCK_DRIFT_TOLERANCE)
+		* bytes_per_sample * CHANNELS_PER_STREAM * cdev->n_streams;
+
+	if (bpp > MAX_ENDPOINT_SIZE)
+		bpp = MAX_ENDPOINT_SIZE;
+
+	ret = snd_usb_caiaq_set_audio_params(cdev, runtime->rate,
+					     runtime->sample_bits, bpp);
+	if (ret)
+		return ret;
+
+	ret = stream_start(cdev);
+	if (ret)
+		return ret;
+
+	cdev->output_running = 0;
+	wait_event_timeout(cdev->prepare_wait_queue, cdev->output_running, HZ);
+	if (!cdev->output_running) {
+		stream_stop(cdev);
+		return -EPIPE;
+	}
+
+	return 0;
+}
+
+static int snd_usb_caiaq_pcm_trigger(struct snd_pcm_substream *sub, int cmd)
+{
+	struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(sub);
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	dev_dbg(dev, "%s(%p) cmd %d\n", __func__, sub, cmd);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		activate_substream(cdev, sub);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		deactivate_substream(cdev, sub);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static snd_pcm_uframes_t
+snd_usb_caiaq_pcm_pointer(struct snd_pcm_substream *sub)
+{
+	int index = sub->number;
+	struct snd_usb_caiaqdev *cdev = snd_pcm_substream_chip(sub);
+
+	guard(spinlock)(&cdev->spinlock);
+
+	if (cdev->input_panic || cdev->output_panic)
+		return SNDRV_PCM_POS_XRUN;
+
+	if (sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		return bytes_to_frames(sub->runtime,
+				       cdev->audio_out_buf_pos[index]);
+	else
+		return bytes_to_frames(sub->runtime,
+				       cdev->audio_in_buf_pos[index]);
+}
+
+/* operators for both playback and capture */
+static const struct snd_pcm_ops snd_usb_caiaq_ops = {
+	.open =		snd_usb_caiaq_substream_open,
+	.close =	snd_usb_caiaq_substream_close,
+	.hw_free =	snd_usb_caiaq_pcm_hw_free,
+	.prepare =	snd_usb_caiaq_pcm_prepare,
+	.trigger =	snd_usb_caiaq_pcm_trigger,
+	.pointer =	snd_usb_caiaq_pcm_pointer,
+};
+
+static void check_for_elapsed_periods(struct snd_usb_caiaqdev *cdev,
+				      struct snd_pcm_substream **subs)
+{
+	int stream, pb, *cnt;
+	struct snd_pcm_substream *sub;
+
+	for (stream = 0; stream < cdev->n_streams; stream++) {
+		sub = subs[stream];
+		if (!sub)
+			continue;
+
+		pb = snd_pcm_lib_period_bytes(sub);
+		cnt = (sub->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
+					&cdev->period_out_count[stream] :
+					&cdev->period_in_count[stream];
+
+		if (*cnt >= pb) {
+			snd_pcm_period_elapsed(sub);
+			*cnt %= pb;
+		}
+	}
+}
+
+static void read_in_urb_mode0(struct snd_usb_caiaqdev *cdev,
+			      const struct urb *urb,
+			      const struct usb_iso_packet_descriptor *iso)
+{
+	unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
+	struct snd_pcm_substream *sub;
+	int stream, i;
+
+	if (all_substreams_zero(cdev->sub_capture))
+		return;
+
+	for (i = 0; i < iso->actual_length;) {
+		for (stream = 0; stream < cdev->n_streams; stream++, i++) {
+			sub = cdev->sub_capture[stream];
+			if (sub) {
+				struct snd_pcm_runtime *rt = sub->runtime;
+				char *audio_buf = rt->dma_area;
+				int sz = frames_to_bytes(rt, rt->buffer_size);
+				audio_buf[cdev->audio_in_buf_pos[stream]++]
+					= usb_buf[i];
+				cdev->period_in_count[stream]++;
+				if (cdev->audio_in_buf_pos[stream] == sz)
+					cdev->audio_in_buf_pos[stream] = 0;
+			}
+		}
+	}
+}
+
+static void read_in_urb_mode2(struct snd_usb_caiaqdev *cdev,
+			      const struct urb *urb,
+			      const struct usb_iso_packet_descriptor *iso)
+{
+	unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
+	unsigned char check_byte;
+	struct snd_pcm_substream *sub;
+	int stream, i;
+
+	for (i = 0; i < iso->actual_length;) {
+		if (i % (cdev->n_streams * BYTES_PER_SAMPLE_USB) == 0) {
+			for (stream = 0;
+			     stream < cdev->n_streams;
+			     stream++, i++) {
+				if (cdev->first_packet)
+					continue;
+
+				check_byte = MAKE_CHECKBYTE(cdev, stream, i);
+
+				if ((usb_buf[i] & 0x3f) != check_byte)
+					cdev->input_panic = 1;
+
+				if (usb_buf[i] & 0x80)
+					cdev->output_panic = 1;
+			}
+		}
+		cdev->first_packet = 0;
+
+		for (stream = 0; stream < cdev->n_streams; stream++, i++) {
+			sub = cdev->sub_capture[stream];
+			if (cdev->input_panic)
+				usb_buf[i] = 0;
+
+			if (sub) {
+				struct snd_pcm_runtime *rt = sub->runtime;
+				char *audio_buf = rt->dma_area;
+				int sz = frames_to_bytes(rt, rt->buffer_size);
+				audio_buf[cdev->audio_in_buf_pos[stream]++] =
+					usb_buf[i];
+				cdev->period_in_count[stream]++;
+				if (cdev->audio_in_buf_pos[stream] == sz)
+					cdev->audio_in_buf_pos[stream] = 0;
+			}
+		}
+	}
+}
+
+static void read_in_urb_mode3(struct snd_usb_caiaqdev *cdev,
+			      const struct urb *urb,
+			      const struct usb_iso_packet_descriptor *iso)
+{
+	unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
+	struct device *dev = caiaqdev_to_dev(cdev);
+	int stream, i;
+
+	/* paranoia check */
+	if (iso->actual_length % (BYTES_PER_SAMPLE_USB * CHANNELS_PER_STREAM))
+		return;
+
+	for (i = 0; i < iso->actual_length;) {
+		for (stream = 0; stream < cdev->n_streams; stream++) {
+			struct snd_pcm_substream *sub = cdev->sub_capture[stream];
+			char *audio_buf = NULL;
+			int c, n, sz = 0;
+
+			if (sub && !cdev->input_panic) {
+				struct snd_pcm_runtime *rt = sub->runtime;
+				audio_buf = rt->dma_area;
+				sz = frames_to_bytes(rt, rt->buffer_size);
+			}
+
+			for (c = 0; c < CHANNELS_PER_STREAM; c++) {
+				/* 3 audio data bytes, followed by 1 check byte */
+				if (audio_buf) {
+					for (n = 0; n < BYTES_PER_SAMPLE; n++) {
+						audio_buf[cdev->audio_in_buf_pos[stream]++] = usb_buf[i+n];
+
+						if (cdev->audio_in_buf_pos[stream] == sz)
+							cdev->audio_in_buf_pos[stream] = 0;
+					}
+
+					cdev->period_in_count[stream] += BYTES_PER_SAMPLE;
+				}
+
+				i += BYTES_PER_SAMPLE;
+
+				if (usb_buf[i] != ((stream << 1) | c) &&
+				    !cdev->first_packet) {
+					if (!cdev->input_panic)
+						dev_warn(dev, " EXPECTED: %02x got %02x, c %d, stream %d, i %d\n",
+							 ((stream << 1) | c), usb_buf[i], c, stream, i);
+					cdev->input_panic = 1;
+				}
+
+				i++;
+			}
+		}
+	}
+
+	if (cdev->first_packet > 0)
+		cdev->first_packet--;
+}
+
+static void read_in_urb(struct snd_usb_caiaqdev *cdev,
+			const struct urb *urb,
+			const struct usb_iso_packet_descriptor *iso)
+{
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	if (!cdev->streaming)
+		return;
+
+	if (iso->actual_length < cdev->bpp)
+		return;
+
+	switch (cdev->spec.data_alignment) {
+	case 0:
+		read_in_urb_mode0(cdev, urb, iso);
+		break;
+	case 2:
+		read_in_urb_mode2(cdev, urb, iso);
+		break;
+	case 3:
+		read_in_urb_mode3(cdev, urb, iso);
+		break;
+	}
+
+	if ((cdev->input_panic || cdev->output_panic) && !cdev->warned) {
+		dev_warn(dev, "streaming error detected %s %s\n",
+				cdev->input_panic ? "(input)" : "",
+				cdev->output_panic ? "(output)" : "");
+		cdev->warned = 1;
+	}
+}
+
+static void fill_out_urb_mode_0(struct snd_usb_caiaqdev *cdev,
+				struct urb *urb,
+				const struct usb_iso_packet_descriptor *iso)
+{
+	unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
+	struct snd_pcm_substream *sub;
+	int stream, i;
+
+	for (i = 0; i < iso->length;) {
+		for (stream = 0; stream < cdev->n_streams; stream++, i++) {
+			sub = cdev->sub_playback[stream];
+			if (sub) {
+				struct snd_pcm_runtime *rt = sub->runtime;
+				char *audio_buf = rt->dma_area;
+				int sz = frames_to_bytes(rt, rt->buffer_size);
+				usb_buf[i] =
+					audio_buf[cdev->audio_out_buf_pos[stream]];
+				cdev->period_out_count[stream]++;
+				cdev->audio_out_buf_pos[stream]++;
+				if (cdev->audio_out_buf_pos[stream] == sz)
+					cdev->audio_out_buf_pos[stream] = 0;
+			} else
+				usb_buf[i] = 0;
+		}
+
+		/* fill in the check bytes */
+		if (cdev->spec.data_alignment == 2 &&
+		    i % (cdev->n_streams * BYTES_PER_SAMPLE_USB) ==
+		        (cdev->n_streams * CHANNELS_PER_STREAM))
+			for (stream = 0; stream < cdev->n_streams; stream++, i++)
+				usb_buf[i] = MAKE_CHECKBYTE(cdev, stream, i);
+	}
+}
+
+static void fill_out_urb_mode_3(struct snd_usb_caiaqdev *cdev,
+				struct urb *urb,
+				const struct usb_iso_packet_descriptor *iso)
+{
+	unsigned char *usb_buf = urb->transfer_buffer + iso->offset;
+	int stream, i;
+
+	for (i = 0; i < iso->length;) {
+		for (stream = 0; stream < cdev->n_streams; stream++) {
+			struct snd_pcm_substream *sub = cdev->sub_playback[stream];
+			char *audio_buf = NULL;
+			int c, n, sz = 0;
+
+			if (sub) {
+				struct snd_pcm_runtime *rt = sub->runtime;
+				audio_buf = rt->dma_area;
+				sz = frames_to_bytes(rt, rt->buffer_size);
+			}
+
+			for (c = 0; c < CHANNELS_PER_STREAM; c++) {
+				for (n = 0; n < BYTES_PER_SAMPLE; n++) {
+					if (audio_buf) {
+						usb_buf[i+n] = audio_buf[cdev->audio_out_buf_pos[stream]++];
+
+						if (cdev->audio_out_buf_pos[stream] == sz)
+							cdev->audio_out_buf_pos[stream] = 0;
+					} else {
+						usb_buf[i+n] = 0;
+					}
+				}
+
+				if (audio_buf)
+					cdev->period_out_count[stream] += BYTES_PER_SAMPLE;
+
+				i += BYTES_PER_SAMPLE;
+
+				/* fill in the check byte pattern */
+				usb_buf[i++] = (stream << 1) | c;
+			}
+		}
+	}
+}
+
+static inline void fill_out_urb(struct snd_usb_caiaqdev *cdev,
+				struct urb *urb,
+				const struct usb_iso_packet_descriptor *iso)
+{
+	switch (cdev->spec.data_alignment) {
+	case 0:
+	case 2:
+		fill_out_urb_mode_0(cdev, urb, iso);
+		break;
+	case 3:
+		fill_out_urb_mode_3(cdev, urb, iso);
+		break;
+	}
+}
+
+static void read_completed(struct urb *urb)
+{
+	struct snd_usb_caiaq_cb_info *info = urb->context;
+	struct snd_usb_caiaqdev *cdev;
+	struct device *dev;
+	struct urb *out = NULL;
+	int i, frame, len, send_it = 0, outframe = 0;
+	size_t offset = 0;
+
+	if (urb->status || !info)
+		return;
+
+	cdev = info->cdev;
+	dev = caiaqdev_to_dev(cdev);
+
+	if (!cdev->streaming)
+		return;
+
+	/* find an unused output urb that is unused */
+	for (i = 0; i < N_URBS; i++)
+		if (test_and_set_bit(i, &cdev->outurb_active_mask) == 0) {
+			out = cdev->data_urbs_out[i];
+			break;
+		}
+
+	if (!out) {
+		dev_err(dev, "Unable to find an output urb to use\n");
+		goto requeue;
+	}
+
+	/* read the recently received packet and send back one which has
+	 * the same layout */
+	for (frame = 0; frame < FRAMES_PER_URB; frame++) {
+		if (urb->iso_frame_desc[frame].status)
+			continue;
+
+		len = urb->iso_frame_desc[outframe].actual_length;
+		out->iso_frame_desc[outframe].length = len;
+		out->iso_frame_desc[outframe].actual_length = 0;
+		out->iso_frame_desc[outframe].offset = offset;
+		offset += len;
+
+		if (len > 0) {
+			scoped_guard(spinlock_irqsave, &cdev->spinlock) {
+				fill_out_urb(cdev, out, &out->iso_frame_desc[outframe]);
+				read_in_urb(cdev, urb, &urb->iso_frame_desc[frame]);
+			}
+			check_for_elapsed_periods(cdev, cdev->sub_playback);
+			check_for_elapsed_periods(cdev, cdev->sub_capture);
+			send_it = 1;
+		}
+
+		outframe++;
+	}
+
+	if (send_it) {
+		out->number_of_packets = outframe;
+		usb_submit_urb(out, GFP_ATOMIC);
+	} else {
+		struct snd_usb_caiaq_cb_info *oinfo = out->context;
+		clear_bit(oinfo->index, &cdev->outurb_active_mask);
+	}
+
+requeue:
+	/* re-submit inbound urb */
+	for (frame = 0; frame < FRAMES_PER_URB; frame++) {
+		urb->iso_frame_desc[frame].offset = BYTES_PER_FRAME * frame;
+		urb->iso_frame_desc[frame].length = BYTES_PER_FRAME;
+		urb->iso_frame_desc[frame].actual_length = 0;
+	}
+
+	urb->number_of_packets = FRAMES_PER_URB;
+	usb_submit_urb(urb, GFP_ATOMIC);
+}
+
+static void write_completed(struct urb *urb)
+{
+	struct snd_usb_caiaq_cb_info *info = urb->context;
+	struct snd_usb_caiaqdev *cdev = info->cdev;
+
+	if (!cdev->output_running) {
+		cdev->output_running = 1;
+		wake_up(&cdev->prepare_wait_queue);
+	}
+
+	clear_bit(info->index, &cdev->outurb_active_mask);
+}
+
+static struct urb **alloc_urbs(struct snd_usb_caiaqdev *cdev, int dir, int *ret)
+{
+	int i, frame;
+	struct urb **urbs;
+	struct usb_device *usb_dev = cdev->chip.dev;
+	unsigned int pipe;
+
+	pipe = (dir == SNDRV_PCM_STREAM_PLAYBACK) ?
+		usb_sndisocpipe(usb_dev, ENDPOINT_PLAYBACK) :
+		usb_rcvisocpipe(usb_dev, ENDPOINT_CAPTURE);
+
+	urbs = kmalloc_objs(*urbs, N_URBS);
+	if (!urbs) {
+		*ret = -ENOMEM;
+		return NULL;
+	}
+
+	for (i = 0; i < N_URBS; i++) {
+		urbs[i] = usb_alloc_urb(FRAMES_PER_URB, GFP_KERNEL);
+		if (!urbs[i]) {
+			*ret = -ENOMEM;
+			return urbs;
+		}
+
+		urbs[i]->transfer_buffer =
+			kmalloc_array(BYTES_PER_FRAME, FRAMES_PER_URB,
+				      GFP_KERNEL);
+		if (!urbs[i]->transfer_buffer) {
+			*ret = -ENOMEM;
+			return urbs;
+		}
+
+		for (frame = 0; frame < FRAMES_PER_URB; frame++) {
+			struct usb_iso_packet_descriptor *iso =
+				&urbs[i]->iso_frame_desc[frame];
+
+			iso->offset = BYTES_PER_FRAME * frame;
+			iso->length = BYTES_PER_FRAME;
+		}
+
+		urbs[i]->dev = usb_dev;
+		urbs[i]->pipe = pipe;
+		urbs[i]->transfer_buffer_length = FRAMES_PER_URB
+						* BYTES_PER_FRAME;
+		urbs[i]->context = &cdev->data_cb_info[i];
+		urbs[i]->interval = 1;
+		urbs[i]->number_of_packets = FRAMES_PER_URB;
+		urbs[i]->complete = (dir == SNDRV_PCM_STREAM_CAPTURE) ?
+					read_completed : write_completed;
+	}
+
+	*ret = 0;
+	return urbs;
+}
+
+static void free_urbs(struct urb **urbs)
+{
+	int i;
+
+	if (!urbs)
+		return;
+
+	for (i = 0; i < N_URBS; i++) {
+		if (!urbs[i])
+			continue;
+
+		usb_kill_urb(urbs[i]);
+		kfree(urbs[i]->transfer_buffer);
+		usb_free_urb(urbs[i]);
+	}
+
+	kfree(urbs);
+}
+
+int snd_usb_caiaq_audio_init(struct snd_usb_caiaqdev *cdev)
+{
+	int i, ret;
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	cdev->n_audio_in  = max(cdev->spec.num_analog_audio_in,
+			       cdev->spec.num_digital_audio_in) /
+				CHANNELS_PER_STREAM;
+	cdev->n_audio_out = max(cdev->spec.num_analog_audio_out,
+			       cdev->spec.num_digital_audio_out) /
+				CHANNELS_PER_STREAM;
+	cdev->n_streams = max(cdev->n_audio_in, cdev->n_audio_out);
+
+	dev_dbg(dev, "cdev->n_audio_in = %d\n", cdev->n_audio_in);
+	dev_dbg(dev, "cdev->n_audio_out = %d\n", cdev->n_audio_out);
+	dev_dbg(dev, "cdev->n_streams = %d\n", cdev->n_streams);
+
+	if (cdev->n_streams > MAX_STREAMS) {
+		dev_err(dev, "unable to initialize device, too many streams.\n");
+		return -EINVAL;
+	}
+
+	if (cdev->n_streams < 1) {
+		dev_err(dev, "bogus number of streams: %d\n", cdev->n_streams);
+		return -EINVAL;
+	}
+
+	ret = snd_pcm_new(cdev->chip.card, cdev->product_name, 0,
+			cdev->n_audio_out, cdev->n_audio_in, &cdev->pcm);
+
+	if (ret < 0) {
+		dev_err(dev, "snd_pcm_new() returned %d\n", ret);
+		return ret;
+	}
+
+	cdev->pcm->private_data = cdev;
+	strscpy(cdev->pcm->name, cdev->product_name, sizeof(cdev->pcm->name));
+
+	memset(cdev->sub_playback, 0, sizeof(cdev->sub_playback));
+	memset(cdev->sub_capture, 0, sizeof(cdev->sub_capture));
+
+	memcpy(&cdev->pcm_info, &snd_usb_caiaq_pcm_hardware,
+			sizeof(snd_usb_caiaq_pcm_hardware));
+
+	/* setup samplerates */
+	cdev->samplerates = cdev->pcm_info.rates;
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AK1):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL3):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_SESSIONIO):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_GUITARRIGMOBILE):
+		cdev->samplerates |= SNDRV_PCM_RATE_192000;
+		fallthrough;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO2DJ):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO4DJ):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO8DJ):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORAUDIO2):
+		cdev->samplerates |= SNDRV_PCM_RATE_88200;
+		break;
+	}
+
+	snd_pcm_set_ops(cdev->pcm, SNDRV_PCM_STREAM_PLAYBACK,
+				&snd_usb_caiaq_ops);
+	snd_pcm_set_ops(cdev->pcm, SNDRV_PCM_STREAM_CAPTURE,
+				&snd_usb_caiaq_ops);
+	snd_pcm_set_managed_buffer_all(cdev->pcm, SNDRV_DMA_TYPE_VMALLOC,
+				       NULL, 0, 0);
+
+	cdev->data_cb_info =
+		kmalloc_objs(struct snd_usb_caiaq_cb_info, N_URBS);
+
+	if (!cdev->data_cb_info)
+		return -ENOMEM;
+
+	cdev->outurb_active_mask = 0;
+	BUILD_BUG_ON(N_URBS > (sizeof(cdev->outurb_active_mask) * 8));
+
+	for (i = 0; i < N_URBS; i++) {
+		cdev->data_cb_info[i].cdev = cdev;
+		cdev->data_cb_info[i].index = i;
+	}
+
+	cdev->data_urbs_in = alloc_urbs(cdev, SNDRV_PCM_STREAM_CAPTURE, &ret);
+	if (ret < 0) {
+		snd_usb_caiaq_audio_free(cdev);
+		return ret;
+	}
+
+	cdev->data_urbs_out = alloc_urbs(cdev, SNDRV_PCM_STREAM_PLAYBACK, &ret);
+	if (ret < 0) {
+		snd_usb_caiaq_audio_free(cdev);
+		return ret;
+	}
+
+	return 0;
+}
+
+void snd_usb_caiaq_audio_disconnect(struct snd_usb_caiaqdev *cdev)
+{
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	dev_dbg(dev, "%s(%p)\n", __func__, cdev);
+	stream_stop(cdev);
+}
+
+void snd_usb_caiaq_audio_free(struct snd_usb_caiaqdev *cdev)
+{
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	dev_dbg(dev, "%s(%p)\n", __func__, cdev);
+	free_urbs(cdev->data_urbs_in);
+	cdev->data_urbs_in = NULL;
+	free_urbs(cdev->data_urbs_out);
+	cdev->data_urbs_out = NULL;
+	kfree(cdev->data_cb_info);
+	cdev->data_cb_info = NULL;
+}
diff --git a/sound/usb/caiaq/audio.h b/sound/usb/caiaq/audio.h
new file mode 100644
index 000000000..07f5d0644
--- /dev/null
+++ b/sound/usb/caiaq/audio.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef CAIAQ_AUDIO_H
+#define CAIAQ_AUDIO_H
+
+int snd_usb_caiaq_audio_init(struct snd_usb_caiaqdev *cdev);
+void snd_usb_caiaq_audio_disconnect(struct snd_usb_caiaqdev *cdev);
+void snd_usb_caiaq_audio_free(struct snd_usb_caiaqdev *cdev);
+
+#endif /* CAIAQ_AUDIO_H */
diff --git a/sound/usb/caiaq/control.c b/sound/usb/caiaq/control.c
new file mode 100644
index 000000000..4598fb7e8
--- /dev/null
+++ b/sound/usb/caiaq/control.c
@@ -0,0 +1,663 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (c) 2007 Daniel Mack
+ *   friendly supported by NI.
+ */
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/usb.h>
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+
+#include "device.h"
+#include "control.h"
+
+#define CNT_INTVAL 0x10000
+#define MASCHINE_BANK_SIZE 32
+
+static int control_info(struct snd_kcontrol *kcontrol,
+			struct snd_ctl_elem_info *uinfo)
+{
+	struct snd_usb_audio *chip = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_caiaqdev *cdev = caiaqdev(chip->card);
+	int pos = kcontrol->private_value;
+	int is_intval = pos & CNT_INTVAL;
+	int maxval = 63;
+
+	uinfo->count = 1;
+	pos &= ~CNT_INTVAL;
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO8DJ):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO4DJ):
+		if (pos == 0) {
+			/* current input mode of A8DJ and A4DJ */
+			uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+			uinfo->value.integer.min = 0;
+			uinfo->value.integer.max = 2;
+			return 0;
+		}
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+		maxval = 127;
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLS4):
+		maxval = 31;
+		break;
+	}
+
+	if (is_intval) {
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+		uinfo->value.integer.min = 0;
+		uinfo->value.integer.max = maxval;
+	} else {
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+		uinfo->value.integer.min = 0;
+		uinfo->value.integer.max = 1;
+	}
+
+	return 0;
+}
+
+static int control_get(struct snd_kcontrol *kcontrol,
+		       struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_usb_audio *chip = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_caiaqdev *cdev = caiaqdev(chip->card);
+	int pos = kcontrol->private_value;
+
+	if (pos & CNT_INTVAL)
+		ucontrol->value.integer.value[0]
+			= cdev->control_state[pos & ~CNT_INTVAL];
+	else
+		ucontrol->value.integer.value[0]
+			= !!(cdev->control_state[pos / 8] & (1 << pos % 8));
+
+	return 0;
+}
+
+static int control_put(struct snd_kcontrol *kcontrol,
+		       struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_usb_audio *chip = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_caiaqdev *cdev = caiaqdev(chip->card);
+	int pos = kcontrol->private_value;
+	int v = ucontrol->value.integer.value[0];
+	int ret;
+	unsigned char cmd;
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER2):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER):
+		cmd = EP1_CMD_DIMM_LEDS;
+		break;
+	default:
+		cmd = EP1_CMD_WRITE_IO;
+		break;
+	}
+
+	if (pos & CNT_INTVAL) {
+		int i = pos & ~CNT_INTVAL;
+		unsigned char old = cdev->control_state[i];
+
+		if (old == v)
+			return 0;
+
+		cdev->control_state[i] = v;
+
+		if (cdev->chip.usb_id ==
+			USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLS4)) {
+			int actual_len;
+
+			cdev->ep8_out_buf[0] = i;
+			cdev->ep8_out_buf[1] = v;
+
+			ret = usb_bulk_msg(cdev->chip.dev,
+					   usb_sndbulkpipe(cdev->chip.dev, 8),
+					   cdev->ep8_out_buf,
+					   sizeof(cdev->ep8_out_buf),
+					   &actual_len, 200);
+		} else if (cdev->chip.usb_id ==
+			USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER)) {
+
+			int bank = 0;
+			int offset = 0;
+
+			if (i >= MASCHINE_BANK_SIZE) {
+				bank = 0x1e;
+				offset = MASCHINE_BANK_SIZE;
+			}
+
+			ret = snd_usb_caiaq_send_command_bank(cdev, cmd, bank,
+							      cdev->control_state + offset,
+							      MASCHINE_BANK_SIZE);
+		} else {
+			ret = snd_usb_caiaq_send_command(cdev, cmd,
+							 cdev->control_state,
+							 sizeof(cdev->control_state));
+		}
+
+		if (ret < 0) {
+			cdev->control_state[i] = old;
+			return ret;
+		}
+	} else {
+		int idx = pos / 8;
+		unsigned char mask = 1 << (pos % 8);
+		unsigned char old = cdev->control_state[idx];
+		unsigned char val = v ? (old | mask) : (old & ~mask);
+
+		if (old == val)
+			return 0;
+
+		cdev->control_state[idx] = val;
+		ret = snd_usb_caiaq_send_command(cdev, cmd,
+						 cdev->control_state,
+						 sizeof(cdev->control_state));
+		if (ret < 0) {
+			cdev->control_state[idx] = old;
+			return ret;
+		}
+	}
+
+	return 1;
+}
+
+static struct snd_kcontrol_new kcontrol_template = {
+	.iface = SNDRV_CTL_ELEM_IFACE_HWDEP,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.index = 0,
+	.info = control_info,
+	.get  = control_get,
+	.put  = control_put,
+	/* name and private_value filled later */
+};
+
+struct caiaq_controller {
+	char *name;
+	int index;
+};
+
+static const struct caiaq_controller ak1_controller[] = {
+	{ "LED left", 	2 },
+	{ "LED middle", 1 },
+	{ "LED right", 	0 },
+	{ "LED ring", 	3 }
+};
+
+static const struct caiaq_controller rk2_controller[] = {
+	{ "LED 1",		5  },
+	{ "LED 2",		4  },
+	{ "LED 3",		3  },
+	{ "LED 4",		2  },
+	{ "LED 5",		1  },
+	{ "LED 6",		0  },
+	{ "LED pedal",		6  },
+	{ "LED 7seg_1b",	8  },
+	{ "LED 7seg_1c",	9  },
+	{ "LED 7seg_2a",	10 },
+	{ "LED 7seg_2b",	11 },
+	{ "LED 7seg_2c",	12 },
+	{ "LED 7seg_2d",	13 },
+	{ "LED 7seg_2e",	14 },
+	{ "LED 7seg_2f",	15 },
+	{ "LED 7seg_2g",	16 },
+	{ "LED 7seg_3a",	17 },
+	{ "LED 7seg_3b",	18 },
+	{ "LED 7seg_3c",	19 },
+	{ "LED 7seg_3d",	20 },
+	{ "LED 7seg_3e",	21 },
+	{ "LED 7seg_3f",	22 },
+	{ "LED 7seg_3g",	23 }
+};
+
+static const struct caiaq_controller rk3_controller[] = {
+	{ "LED 7seg_1a",        0 + 0 },
+	{ "LED 7seg_1b",        0 + 1 },
+	{ "LED 7seg_1c",        0 + 2 },
+	{ "LED 7seg_1d",        0 + 3 },
+	{ "LED 7seg_1e",        0 + 4 },
+	{ "LED 7seg_1f",        0 + 5 },
+	{ "LED 7seg_1g",        0 + 6 },
+	{ "LED 7seg_1p",        0 + 7 },
+
+	{ "LED 7seg_2a",        8 + 0 },
+	{ "LED 7seg_2b",        8 + 1 },
+	{ "LED 7seg_2c",        8 + 2 },
+	{ "LED 7seg_2d",        8 + 3 },
+	{ "LED 7seg_2e",        8 + 4 },
+	{ "LED 7seg_2f",        8 + 5 },
+	{ "LED 7seg_2g",        8 + 6 },
+	{ "LED 7seg_2p",        8 + 7 },
+
+	{ "LED 7seg_3a",        16 + 0 },
+	{ "LED 7seg_3b",        16 + 1 },
+	{ "LED 7seg_3c",        16 + 2 },
+	{ "LED 7seg_3d",        16 + 3 },
+	{ "LED 7seg_3e",        16 + 4 },
+	{ "LED 7seg_3f",        16 + 5 },
+	{ "LED 7seg_3g",        16 + 6 },
+	{ "LED 7seg_3p",        16 + 7 },
+
+	{ "LED 7seg_4a",        24 + 0 },
+	{ "LED 7seg_4b",        24 + 1 },
+	{ "LED 7seg_4c",        24 + 2 },
+	{ "LED 7seg_4d",        24 + 3 },
+	{ "LED 7seg_4e",        24 + 4 },
+	{ "LED 7seg_4f",        24 + 5 },
+	{ "LED 7seg_4g",        24 + 6 },
+	{ "LED 7seg_4p",        24 + 7 },
+
+	{ "LED 1",		32 + 0 },
+	{ "LED 2",		32 + 1 },
+	{ "LED 3",		32 + 2 },
+	{ "LED 4",		32 + 3 },
+	{ "LED 5",		32 + 4 },
+	{ "LED 6",		32 + 5 },
+	{ "LED 7",		32 + 6 },
+	{ "LED 8",		32 + 7 },
+	{ "LED pedal",		32 + 8 }
+};
+
+static const struct caiaq_controller kore_controller[] = {
+	{ "LED F1",		8   | CNT_INTVAL },
+	{ "LED F2",		12  | CNT_INTVAL },
+	{ "LED F3",		0   | CNT_INTVAL },
+	{ "LED F4",		4   | CNT_INTVAL },
+	{ "LED F5",		11  | CNT_INTVAL },
+	{ "LED F6",		15  | CNT_INTVAL },
+	{ "LED F7",		3   | CNT_INTVAL },
+	{ "LED F8",		7   | CNT_INTVAL },
+	{ "LED touch1",	     	10  | CNT_INTVAL },
+	{ "LED touch2",	     	14  | CNT_INTVAL },
+	{ "LED touch3",	     	2   | CNT_INTVAL },
+	{ "LED touch4",	     	6   | CNT_INTVAL },
+	{ "LED touch5",	     	9   | CNT_INTVAL },
+	{ "LED touch6",	     	13  | CNT_INTVAL },
+	{ "LED touch7",	     	1   | CNT_INTVAL },
+	{ "LED touch8",	     	5   | CNT_INTVAL },
+	{ "LED left",	       	18  | CNT_INTVAL },
+	{ "LED right",	     	22  | CNT_INTVAL },
+	{ "LED up",		16  | CNT_INTVAL },
+	{ "LED down",	       	20  | CNT_INTVAL },
+	{ "LED stop",	       	23  | CNT_INTVAL },
+	{ "LED play",	       	21  | CNT_INTVAL },
+	{ "LED record",	     	19  | CNT_INTVAL },
+	{ "LED listen",		17  | CNT_INTVAL },
+	{ "LED lcd",		30  | CNT_INTVAL },
+	{ "LED menu",		28  | CNT_INTVAL },
+	{ "LED sound",	 	31  | CNT_INTVAL },
+	{ "LED esc",		29  | CNT_INTVAL },
+	{ "LED view",		27  | CNT_INTVAL },
+	{ "LED enter",		24  | CNT_INTVAL },
+	{ "LED control",	26  | CNT_INTVAL }
+};
+
+static const struct caiaq_controller a8dj_controller[] = {
+	{ "Current input mode",			0 | CNT_INTVAL 	},
+	{ "GND lift for TC Vinyl mode", 	24 + 0 		},
+	{ "GND lift for TC CD/Line mode", 	24 + 1 		},
+	{ "GND lift for phono mode", 		24 + 2 		},
+	{ "Software lock", 			40 		}
+};
+
+static const struct caiaq_controller a4dj_controller[] = {
+	{ "Current input mode",	0 | CNT_INTVAL 	}
+};
+
+static const struct caiaq_controller kontrolx1_controller[] = {
+	{ "LED FX A: ON",		7 | CNT_INTVAL	},
+	{ "LED FX A: 1",		6 | CNT_INTVAL	},
+	{ "LED FX A: 2",		5 | CNT_INTVAL	},
+	{ "LED FX A: 3",		4 | CNT_INTVAL	},
+	{ "LED FX B: ON",		3 | CNT_INTVAL	},
+	{ "LED FX B: 1",		2 | CNT_INTVAL	},
+	{ "LED FX B: 2",		1 | CNT_INTVAL	},
+	{ "LED FX B: 3",		0 | CNT_INTVAL	},
+
+	{ "LED Hotcue",			28 | CNT_INTVAL	},
+	{ "LED Shift (white)",		29 | CNT_INTVAL	},
+	{ "LED Shift (green)",		30 | CNT_INTVAL	},
+
+	{ "LED Deck A: FX1",		24 | CNT_INTVAL	},
+	{ "LED Deck A: FX2",		25 | CNT_INTVAL	},
+	{ "LED Deck A: IN",		17 | CNT_INTVAL	},
+	{ "LED Deck A: OUT",		16 | CNT_INTVAL	},
+	{ "LED Deck A: < BEAT",		19 | CNT_INTVAL	},
+	{ "LED Deck A: BEAT >",		18 | CNT_INTVAL	},
+	{ "LED Deck A: CUE/ABS",	21 | CNT_INTVAL	},
+	{ "LED Deck A: CUP/REL",	20 | CNT_INTVAL	},
+	{ "LED Deck A: PLAY",		23 | CNT_INTVAL	},
+	{ "LED Deck A: SYNC",		22 | CNT_INTVAL	},
+
+	{ "LED Deck B: FX1",		26 | CNT_INTVAL	},
+	{ "LED Deck B: FX2",		27 | CNT_INTVAL	},
+	{ "LED Deck B: IN",		15 | CNT_INTVAL	},
+	{ "LED Deck B: OUT",		14 | CNT_INTVAL	},
+	{ "LED Deck B: < BEAT",		13 | CNT_INTVAL	},
+	{ "LED Deck B: BEAT >",		12 | CNT_INTVAL	},
+	{ "LED Deck B: CUE/ABS",	11 | CNT_INTVAL	},
+	{ "LED Deck B: CUP/REL",	10 | CNT_INTVAL	},
+	{ "LED Deck B: PLAY",		9  | CNT_INTVAL	},
+	{ "LED Deck B: SYNC",		8  | CNT_INTVAL	},
+};
+
+static const struct caiaq_controller kontrols4_controller[] = {
+	{ "LED: Master: Quant",			10  | CNT_INTVAL },
+	{ "LED: Master: Headphone",		11  | CNT_INTVAL },
+	{ "LED: Master: Master",		12  | CNT_INTVAL },
+	{ "LED: Master: Snap",			14  | CNT_INTVAL },
+	{ "LED: Master: Warning",		15  | CNT_INTVAL },
+	{ "LED: Master: Master button",		112 | CNT_INTVAL },
+	{ "LED: Master: Snap button",		113 | CNT_INTVAL },
+	{ "LED: Master: Rec",			118 | CNT_INTVAL },
+	{ "LED: Master: Size",			119 | CNT_INTVAL },
+	{ "LED: Master: Quant button",		120 | CNT_INTVAL },
+	{ "LED: Master: Browser button",	121 | CNT_INTVAL },
+	{ "LED: Master: Play button",		126 | CNT_INTVAL },
+	{ "LED: Master: Undo button",		127 | CNT_INTVAL },
+
+	{ "LED: Channel A: >",			4   | CNT_INTVAL },
+	{ "LED: Channel A: <",			5   | CNT_INTVAL },
+	{ "LED: Channel A: Meter 1",		97  | CNT_INTVAL },
+	{ "LED: Channel A: Meter 2",		98  | CNT_INTVAL },
+	{ "LED: Channel A: Meter 3",		99  | CNT_INTVAL },
+	{ "LED: Channel A: Meter 4",		100 | CNT_INTVAL },
+	{ "LED: Channel A: Meter 5",		101 | CNT_INTVAL },
+	{ "LED: Channel A: Meter 6",		102 | CNT_INTVAL },
+	{ "LED: Channel A: Meter clip",		103 | CNT_INTVAL },
+	{ "LED: Channel A: Active",		114 | CNT_INTVAL },
+	{ "LED: Channel A: Cue",		116 | CNT_INTVAL },
+	{ "LED: Channel A: FX1",		149 | CNT_INTVAL },
+	{ "LED: Channel A: FX2",		148 | CNT_INTVAL },
+
+	{ "LED: Channel B: >",			2   | CNT_INTVAL },
+	{ "LED: Channel B: <",			3   | CNT_INTVAL },
+	{ "LED: Channel B: Meter 1",		89  | CNT_INTVAL },
+	{ "LED: Channel B: Meter 2",		90  | CNT_INTVAL },
+	{ "LED: Channel B: Meter 3",		91  | CNT_INTVAL },
+	{ "LED: Channel B: Meter 4",		92  | CNT_INTVAL },
+	{ "LED: Channel B: Meter 5",		93  | CNT_INTVAL },
+	{ "LED: Channel B: Meter 6",		94  | CNT_INTVAL },
+	{ "LED: Channel B: Meter clip",		95  | CNT_INTVAL },
+	{ "LED: Channel B: Active",		122 | CNT_INTVAL },
+	{ "LED: Channel B: Cue",		125 | CNT_INTVAL },
+	{ "LED: Channel B: FX1",		147 | CNT_INTVAL },
+	{ "LED: Channel B: FX2",		146 | CNT_INTVAL },
+
+	{ "LED: Channel C: >",			6   | CNT_INTVAL },
+	{ "LED: Channel C: <",			7   | CNT_INTVAL },
+	{ "LED: Channel C: Meter 1",		105 | CNT_INTVAL },
+	{ "LED: Channel C: Meter 2",		106 | CNT_INTVAL },
+	{ "LED: Channel C: Meter 3",		107 | CNT_INTVAL },
+	{ "LED: Channel C: Meter 4",		108 | CNT_INTVAL },
+	{ "LED: Channel C: Meter 5",		109 | CNT_INTVAL },
+	{ "LED: Channel C: Meter 6",		110 | CNT_INTVAL },
+	{ "LED: Channel C: Meter clip",		111 | CNT_INTVAL },
+	{ "LED: Channel C: Active",		115 | CNT_INTVAL },
+	{ "LED: Channel C: Cue",		117 | CNT_INTVAL },
+	{ "LED: Channel C: FX1",		151 | CNT_INTVAL },
+	{ "LED: Channel C: FX2",		150 | CNT_INTVAL },
+
+	{ "LED: Channel D: >",			0   | CNT_INTVAL },
+	{ "LED: Channel D: <",			1   | CNT_INTVAL },
+	{ "LED: Channel D: Meter 1",		81  | CNT_INTVAL },
+	{ "LED: Channel D: Meter 2",		82  | CNT_INTVAL },
+	{ "LED: Channel D: Meter 3",		83  | CNT_INTVAL },
+	{ "LED: Channel D: Meter 4",		84  | CNT_INTVAL },
+	{ "LED: Channel D: Meter 5",		85  | CNT_INTVAL },
+	{ "LED: Channel D: Meter 6",		86  | CNT_INTVAL },
+	{ "LED: Channel D: Meter clip",		87  | CNT_INTVAL },
+	{ "LED: Channel D: Active",		123 | CNT_INTVAL },
+	{ "LED: Channel D: Cue",		124 | CNT_INTVAL },
+	{ "LED: Channel D: FX1",		145 | CNT_INTVAL },
+	{ "LED: Channel D: FX2",		144 | CNT_INTVAL },
+
+	{ "LED: Deck A: 1 (blue)",		22  | CNT_INTVAL },
+	{ "LED: Deck A: 1 (green)",		23  | CNT_INTVAL },
+	{ "LED: Deck A: 2 (blue)",		20  | CNT_INTVAL },
+	{ "LED: Deck A: 2 (green)",		21  | CNT_INTVAL },
+	{ "LED: Deck A: 3 (blue)",		18  | CNT_INTVAL },
+	{ "LED: Deck A: 3 (green)",		19  | CNT_INTVAL },
+	{ "LED: Deck A: 4 (blue)",		16  | CNT_INTVAL },
+	{ "LED: Deck A: 4 (green)",		17  | CNT_INTVAL },
+	{ "LED: Deck A: Load",			44  | CNT_INTVAL },
+	{ "LED: Deck A: Deck C button",		45  | CNT_INTVAL },
+	{ "LED: Deck A: In",			47  | CNT_INTVAL },
+	{ "LED: Deck A: Out",			46  | CNT_INTVAL },
+	{ "LED: Deck A: Shift",			24  | CNT_INTVAL },
+	{ "LED: Deck A: Sync",			27  | CNT_INTVAL },
+	{ "LED: Deck A: Cue",			26  | CNT_INTVAL },
+	{ "LED: Deck A: Play",			25  | CNT_INTVAL },
+	{ "LED: Deck A: Tempo up",		33  | CNT_INTVAL },
+	{ "LED: Deck A: Tempo down",		32  | CNT_INTVAL },
+	{ "LED: Deck A: Master",		34  | CNT_INTVAL },
+	{ "LED: Deck A: Keylock",		35  | CNT_INTVAL },
+	{ "LED: Deck A: Deck A",		37  | CNT_INTVAL },
+	{ "LED: Deck A: Deck C",		36  | CNT_INTVAL },
+	{ "LED: Deck A: Samples",		38  | CNT_INTVAL },
+	{ "LED: Deck A: On Air",		39  | CNT_INTVAL },
+	{ "LED: Deck A: Sample 1",		31  | CNT_INTVAL },
+	{ "LED: Deck A: Sample 2",		30  | CNT_INTVAL },
+	{ "LED: Deck A: Sample 3",		29  | CNT_INTVAL },
+	{ "LED: Deck A: Sample 4",		28  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 1 - A",		55  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 1 - B",		54  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 1 - C",		53  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 1 - D",		52  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 1 - E",		51  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 1 - F",		50  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 1 - G",		49  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 1 - dot",		48  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 2 - A",		63  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 2 - B",		62  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 2 - C",		61  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 2 - D",		60  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 2 - E",		59  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 2 - F",		58  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 2 - G",		57  | CNT_INTVAL },
+	{ "LED: Deck A: Digit 2 - dot",		56  | CNT_INTVAL },
+
+	{ "LED: Deck B: 1 (blue)",		78  | CNT_INTVAL },
+	{ "LED: Deck B: 1 (green)",		79  | CNT_INTVAL },
+	{ "LED: Deck B: 2 (blue)",		76  | CNT_INTVAL },
+	{ "LED: Deck B: 2 (green)",		77  | CNT_INTVAL },
+	{ "LED: Deck B: 3 (blue)",		74  | CNT_INTVAL },
+	{ "LED: Deck B: 3 (green)",		75  | CNT_INTVAL },
+	{ "LED: Deck B: 4 (blue)",		72  | CNT_INTVAL },
+	{ "LED: Deck B: 4 (green)",		73  | CNT_INTVAL },
+	{ "LED: Deck B: Load",			180 | CNT_INTVAL },
+	{ "LED: Deck B: Deck D button",		181 | CNT_INTVAL },
+	{ "LED: Deck B: In",			183 | CNT_INTVAL },
+	{ "LED: Deck B: Out",			182 | CNT_INTVAL },
+	{ "LED: Deck B: Shift",			64  | CNT_INTVAL },
+	{ "LED: Deck B: Sync",			67  | CNT_INTVAL },
+	{ "LED: Deck B: Cue",			66  | CNT_INTVAL },
+	{ "LED: Deck B: Play",			65  | CNT_INTVAL },
+	{ "LED: Deck B: Tempo up",		185 | CNT_INTVAL },
+	{ "LED: Deck B: Tempo down",		184 | CNT_INTVAL },
+	{ "LED: Deck B: Master",		186 | CNT_INTVAL },
+	{ "LED: Deck B: Keylock",		187 | CNT_INTVAL },
+	{ "LED: Deck B: Deck B",		189 | CNT_INTVAL },
+	{ "LED: Deck B: Deck D",		188 | CNT_INTVAL },
+	{ "LED: Deck B: Samples",		190 | CNT_INTVAL },
+	{ "LED: Deck B: On Air",		191 | CNT_INTVAL },
+	{ "LED: Deck B: Sample 1",		71  | CNT_INTVAL },
+	{ "LED: Deck B: Sample 2",		70  | CNT_INTVAL },
+	{ "LED: Deck B: Sample 3",		69  | CNT_INTVAL },
+	{ "LED: Deck B: Sample 4",		68  | CNT_INTVAL },
+	{ "LED: Deck B: Digit 1 - A",		175 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 1 - B",		174 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 1 - C",		173 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 1 - D",		172 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 1 - E",		171 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 1 - F",		170 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 1 - G",		169 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 1 - dot",		168 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 2 - A",		167 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 2 - B",		166 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 2 - C",		165 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 2 - D",		164 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 2 - E",		163 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 2 - F",		162 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 2 - G",		161 | CNT_INTVAL },
+	{ "LED: Deck B: Digit 2 - dot",		160 | CNT_INTVAL },
+
+	{ "LED: FX1: dry/wet",			153 | CNT_INTVAL },
+	{ "LED: FX1: 1",			154 | CNT_INTVAL },
+	{ "LED: FX1: 2",			155 | CNT_INTVAL },
+	{ "LED: FX1: 3",			156 | CNT_INTVAL },
+	{ "LED: FX1: Mode",			157 | CNT_INTVAL },
+	{ "LED: FX2: dry/wet",			129 | CNT_INTVAL },
+	{ "LED: FX2: 1",			130 | CNT_INTVAL },
+	{ "LED: FX2: 2",			131 | CNT_INTVAL },
+	{ "LED: FX2: 3",			132 | CNT_INTVAL },
+	{ "LED: FX2: Mode",			133 | CNT_INTVAL },
+};
+
+static const struct caiaq_controller maschine_controller[] = {
+	{ "LED: Pad 1",				3  | CNT_INTVAL },
+	{ "LED: Pad 2",				2  | CNT_INTVAL },
+	{ "LED: Pad 3",				1  | CNT_INTVAL },
+	{ "LED: Pad 4",				0  | CNT_INTVAL },
+	{ "LED: Pad 5",				7  | CNT_INTVAL },
+	{ "LED: Pad 6",				6  | CNT_INTVAL },
+	{ "LED: Pad 7",				5  | CNT_INTVAL },
+	{ "LED: Pad 8",				4  | CNT_INTVAL },
+	{ "LED: Pad 9",				11 | CNT_INTVAL },
+	{ "LED: Pad 10",			10 | CNT_INTVAL },
+	{ "LED: Pad 11",			9  | CNT_INTVAL },
+	{ "LED: Pad 12",			8  | CNT_INTVAL },
+	{ "LED: Pad 13",			15 | CNT_INTVAL },
+	{ "LED: Pad 14",			14 | CNT_INTVAL },
+	{ "LED: Pad 15",			13 | CNT_INTVAL },
+	{ "LED: Pad 16",			12 | CNT_INTVAL },
+
+	{ "LED: Mute",				16 | CNT_INTVAL },
+	{ "LED: Solo",				17 | CNT_INTVAL },
+	{ "LED: Select",			18 | CNT_INTVAL },
+	{ "LED: Duplicate",			19 | CNT_INTVAL },
+	{ "LED: Navigate",			20 | CNT_INTVAL },
+	{ "LED: Pad Mode",			21 | CNT_INTVAL },
+	{ "LED: Pattern",			22 | CNT_INTVAL },
+	{ "LED: Scene",				23 | CNT_INTVAL },
+
+	{ "LED: Shift",				24 | CNT_INTVAL },
+	{ "LED: Erase",				25 | CNT_INTVAL },
+	{ "LED: Grid",				26 | CNT_INTVAL },
+	{ "LED: Right Bottom",			27 | CNT_INTVAL },
+	{ "LED: Rec",				28 | CNT_INTVAL },
+	{ "LED: Play",				29 | CNT_INTVAL },
+	{ "LED: Left Bottom",			32 | CNT_INTVAL },
+	{ "LED: Restart",			33 | CNT_INTVAL },
+
+	{ "LED: Group A",			41 | CNT_INTVAL },
+	{ "LED: Group B",			40 | CNT_INTVAL },
+	{ "LED: Group C",			37 | CNT_INTVAL },
+	{ "LED: Group D",			36 | CNT_INTVAL },
+	{ "LED: Group E",			39 | CNT_INTVAL },
+	{ "LED: Group F",			38 | CNT_INTVAL },
+	{ "LED: Group G",			35 | CNT_INTVAL },
+	{ "LED: Group H",			34 | CNT_INTVAL },
+
+	{ "LED: Auto Write",			42 | CNT_INTVAL },
+	{ "LED: Snap",				43 | CNT_INTVAL },
+	{ "LED: Right Top",			44 | CNT_INTVAL },
+	{ "LED: Left Top",			45 | CNT_INTVAL },
+	{ "LED: Sampling",			46 | CNT_INTVAL },
+	{ "LED: Browse",			47 | CNT_INTVAL },
+	{ "LED: Step",				48 | CNT_INTVAL },
+	{ "LED: Control",			49 | CNT_INTVAL },
+
+	{ "LED: Top Button 1",			57 | CNT_INTVAL },
+	{ "LED: Top Button 2",			56 | CNT_INTVAL },
+	{ "LED: Top Button 3",			55 | CNT_INTVAL },
+	{ "LED: Top Button 4",			54 | CNT_INTVAL },
+	{ "LED: Top Button 5",			53 | CNT_INTVAL },
+	{ "LED: Top Button 6",			52 | CNT_INTVAL },
+	{ "LED: Top Button 7",			51 | CNT_INTVAL },
+	{ "LED: Top Button 8",			50 | CNT_INTVAL },
+
+	{ "LED: Note Repeat",			58 | CNT_INTVAL },
+
+	{ "Backlight Display",			59 | CNT_INTVAL }
+};
+
+static int add_controls(const struct caiaq_controller *c, int num,
+			struct snd_usb_caiaqdev *cdev)
+{
+	int i, ret;
+	struct snd_kcontrol *kc;
+
+	for (i = 0; i < num; i++, c++) {
+		kcontrol_template.name = c->name;
+		kcontrol_template.private_value = c->index;
+		kc = snd_ctl_new1(&kcontrol_template, cdev);
+		ret = snd_ctl_add(cdev->chip.card, kc);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+int snd_usb_caiaq_control_init(struct snd_usb_caiaqdev *cdev)
+{
+	int ret = 0;
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AK1):
+		ret = add_controls(ak1_controller,
+			ARRAY_SIZE(ak1_controller), cdev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL2):
+		ret = add_controls(rk2_controller,
+			ARRAY_SIZE(rk2_controller), cdev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL3):
+		ret = add_controls(rk3_controller,
+			ARRAY_SIZE(rk3_controller), cdev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER2):
+		ret = add_controls(kore_controller,
+			ARRAY_SIZE(kore_controller), cdev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO8DJ):
+		ret = add_controls(a8dj_controller,
+			ARRAY_SIZE(a8dj_controller), cdev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO4DJ):
+		ret = add_controls(a4dj_controller,
+			ARRAY_SIZE(a4dj_controller), cdev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+		ret = add_controls(kontrolx1_controller,
+			ARRAY_SIZE(kontrolx1_controller), cdev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLS4):
+		ret = add_controls(kontrols4_controller,
+			ARRAY_SIZE(kontrols4_controller), cdev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER):
+		ret = add_controls(maschine_controller,
+			ARRAY_SIZE(maschine_controller), cdev);
+		break;
+	}
+
+	return ret;
+}
diff --git a/sound/usb/caiaq/control.h b/sound/usb/caiaq/control.h
new file mode 100644
index 000000000..cb204fd45
--- /dev/null
+++ b/sound/usb/caiaq/control.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef CAIAQ_CONTROL_H
+#define CAIAQ_CONTROL_H
+
+int snd_usb_caiaq_control_init(struct snd_usb_caiaqdev *cdev);
+
+#endif /* CAIAQ_CONTROL_H */
diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
new file mode 100644
index 000000000..f604846ec
--- /dev/null
+++ b/sound/usb/caiaq/device.c
@@ -0,0 +1,609 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * caiaq.c: ALSA driver for caiaq/NativeInstruments devices
+ *
+ *   Copyright (c) 2007 Daniel Mack <daniel@caiaq.de>
+ *                      Karsten Wiese <fzu@wemgehoertderstaat.de>
+*/
+
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/gfp.h>
+#include <linux/usb.h>
+#include <sound/initval.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+
+#include "device.h"
+#include "audio.h"
+#include "midi.h"
+#include "control.h"
+#include "input.h"
+
+MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
+MODULE_DESCRIPTION("caiaq USB audio");
+MODULE_LICENSE("GPL");
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-max */
+static char* id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* Id for this card */
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP; /* Enable this card */
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "Index value for the caiaq sound device");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string for the caiaq soundcard.");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "Enable the caiaq soundcard.");
+
+enum {
+	SAMPLERATE_44100	= 0,
+	SAMPLERATE_48000	= 1,
+	SAMPLERATE_96000	= 2,
+	SAMPLERATE_192000	= 3,
+	SAMPLERATE_88200	= 4,
+	SAMPLERATE_INVALID	= 0xff
+};
+
+enum {
+	DEPTH_NONE	= 0,
+	DEPTH_16	= 1,
+	DEPTH_24	= 2,
+	DEPTH_32	= 3
+};
+
+static const struct usb_device_id snd_usb_id_table[] = {
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =	USB_PID_RIGKONTROL2
+	},
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =	USB_PID_RIGKONTROL3
+	},
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =	USB_PID_KORECONTROLLER
+	},
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =	USB_PID_KORECONTROLLER2
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_AK1
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_AUDIO8DJ
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_SESSIONIO
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_GUITARRIGMOBILE
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_AUDIO4DJ
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_AUDIO2DJ
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_TRAKTORKONTROLX1
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_TRAKTORKONTROLS4
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_TRAKTORAUDIO2
+	},
+	{
+		.match_flags =  USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =     USB_VID_NATIVEINSTRUMENTS,
+		.idProduct =    USB_PID_MASCHINECONTROLLER
+	},
+	{ /* terminator */ }
+};
+
+static void usb_ep1_command_reply_dispatch (struct urb* urb)
+{
+	int ret;
+	struct device *dev = &urb->dev->dev;
+	struct snd_usb_caiaqdev *cdev = urb->context;
+	unsigned char *buf = urb->transfer_buffer;
+	unsigned int payload_len;
+	unsigned int copy_len;
+
+	if (urb->status || !cdev) {
+		dev_warn(dev, "received EP1 urb->status = %i\n", urb->status);
+		return;
+	}
+	if (urb->actual_length < 1)
+		return;
+
+	payload_len = urb->actual_length - 1;
+
+	switch(buf[0]) {
+	case EP1_CMD_GET_DEVICE_INFO:
+		if (payload_len < sizeof(struct caiaq_device_spec))
+			break;
+	 	memcpy(&cdev->spec, buf+1, sizeof(struct caiaq_device_spec));
+		cdev->spec.fw_version = le16_to_cpu(cdev->spec.fw_version);
+		dev_dbg(dev, "device spec (firmware %d): audio: %d in, %d out, "
+			"MIDI: %d in, %d out, data alignment %d\n",
+			cdev->spec.fw_version,
+			cdev->spec.num_analog_audio_in,
+			cdev->spec.num_analog_audio_out,
+			cdev->spec.num_midi_in,
+			cdev->spec.num_midi_out,
+			cdev->spec.data_alignment);
+
+		cdev->spec_received++;
+		wake_up(&cdev->ep1_wait_queue);
+		break;
+	case EP1_CMD_AUDIO_PARAMS:
+		if (payload_len < 1)
+			break;
+		cdev->audio_parm_answer = buf[1];
+		wake_up(&cdev->ep1_wait_queue);
+		break;
+	case EP1_CMD_MIDI_READ:
+		if (urb->actual_length < 3 || urb->actual_length - 3 < buf[2])
+			break;
+		snd_usb_caiaq_midi_handle_input(cdev, buf[1], buf + 3, buf[2]);
+		break;
+	case EP1_CMD_READ_IO:
+		if (cdev->chip.usb_id ==
+			USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO8DJ)) {
+			copy_len = min_t(unsigned int, payload_len, sizeof(cdev->control_state));
+			memcpy(cdev->control_state, buf + 1, copy_len);
+			wake_up(&cdev->ep1_wait_queue);
+			break;
+		}
+#ifdef CONFIG_SND_USB_CAIAQ_INPUT
+		fallthrough;
+	case EP1_CMD_READ_ERP:
+	case EP1_CMD_READ_ANALOG:
+		snd_usb_caiaq_input_dispatch(cdev, buf, urb->actual_length);
+#endif
+		break;
+	}
+
+	cdev->ep1_in_urb->actual_length = 0;
+	ret = usb_submit_urb(cdev->ep1_in_urb, GFP_ATOMIC);
+	if (ret < 0)
+		dev_err(dev, "unable to submit urb. OOM!?\n");
+}
+
+int snd_usb_caiaq_send_command(struct snd_usb_caiaqdev *cdev,
+			       unsigned char command,
+			       const unsigned char *buffer,
+			       int len)
+{
+	int actual_len;
+	struct usb_device *usb_dev = cdev->chip.dev;
+
+	if (!usb_dev)
+		return -EIO;
+
+	if (len > EP1_BUFSIZE - 1)
+		len = EP1_BUFSIZE - 1;
+
+	if (buffer && len > 0)
+		memcpy(cdev->ep1_out_buf+1, buffer, len);
+
+	cdev->ep1_out_buf[0] = command;
+	return usb_bulk_msg(usb_dev, usb_sndbulkpipe(usb_dev, 1),
+			   cdev->ep1_out_buf, len+1, &actual_len, 200);
+}
+
+int snd_usb_caiaq_send_command_bank(struct snd_usb_caiaqdev *cdev,
+			       unsigned char command,
+			       unsigned char bank,
+			       const unsigned char *buffer,
+			       int len)
+{
+	int actual_len;
+	struct usb_device *usb_dev = cdev->chip.dev;
+
+	if (!usb_dev)
+		return -EIO;
+
+	if (len > EP1_BUFSIZE - 2)
+		len = EP1_BUFSIZE - 2;
+
+	if (buffer && len > 0)
+		memcpy(cdev->ep1_out_buf+2, buffer, len);
+
+	cdev->ep1_out_buf[0] = command;
+	cdev->ep1_out_buf[1] = bank;
+
+	return usb_bulk_msg(usb_dev, usb_sndbulkpipe(usb_dev, 1),
+			   cdev->ep1_out_buf, len+2, &actual_len, 200);
+}
+
+int snd_usb_caiaq_set_audio_params (struct snd_usb_caiaqdev *cdev,
+		   		    int rate, int depth, int bpp)
+{
+	int ret;
+	char tmp[5];
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	switch (rate) {
+	case 44100:	tmp[0] = SAMPLERATE_44100;   break;
+	case 48000:	tmp[0] = SAMPLERATE_48000;   break;
+	case 88200:	tmp[0] = SAMPLERATE_88200;   break;
+	case 96000:	tmp[0] = SAMPLERATE_96000;   break;
+	case 192000:	tmp[0] = SAMPLERATE_192000;  break;
+	default:	return -EINVAL;
+	}
+
+	switch (depth) {
+	case 16:	tmp[1] = DEPTH_16;   break;
+	case 24:	tmp[1] = DEPTH_24;   break;
+	default:	return -EINVAL;
+	}
+
+	tmp[2] = bpp & 0xff;
+	tmp[3] = bpp >> 8;
+	tmp[4] = 1; /* packets per microframe */
+
+	dev_dbg(dev, "setting audio params: %d Hz, %d bits, %d bpp\n",
+		rate, depth, bpp);
+
+	cdev->audio_parm_answer = -1;
+	ret = snd_usb_caiaq_send_command(cdev, EP1_CMD_AUDIO_PARAMS,
+					 tmp, sizeof(tmp));
+
+	if (ret)
+		return ret;
+
+	if (!wait_event_timeout(cdev->ep1_wait_queue,
+	    cdev->audio_parm_answer >= 0, HZ))
+		return -EPIPE;
+
+	if (cdev->audio_parm_answer != 1)
+		dev_dbg(dev, "unable to set the device's audio params\n");
+	else
+		cdev->bpp = bpp;
+
+	return cdev->audio_parm_answer == 1 ? 0 : -EINVAL;
+}
+
+int snd_usb_caiaq_set_auto_msg(struct snd_usb_caiaqdev *cdev,
+			       int digital, int analog, int erp)
+{
+	char tmp[3] = { digital, analog, erp };
+	return snd_usb_caiaq_send_command(cdev, EP1_CMD_AUTO_MSG,
+					  tmp, sizeof(tmp));
+}
+
+static int setup_card(struct snd_usb_caiaqdev *cdev)
+{
+	int ret;
+	char val[4];
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	/* device-specific startup specials */
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL2):
+		/* RigKontrol2 - display centered dash ('-') */
+		val[0] = 0x00;
+		val[1] = 0x00;
+		val[2] = 0x01;
+		snd_usb_caiaq_send_command(cdev, EP1_CMD_WRITE_IO, val, 3);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL3):
+		/* RigKontrol2 - display two centered dashes ('--') */
+		val[0] = 0x00;
+		val[1] = 0x40;
+		val[2] = 0x40;
+		val[3] = 0x00;
+		snd_usb_caiaq_send_command(cdev, EP1_CMD_WRITE_IO, val, 4);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AK1):
+		/* Audio Kontrol 1 - make USB-LED stop blinking */
+		val[0] = 0x00;
+		snd_usb_caiaq_send_command(cdev, EP1_CMD_WRITE_IO, val, 1);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO8DJ):
+		/* Audio 8 DJ - trigger read of current settings */
+		cdev->control_state[0] = 0xff;
+		snd_usb_caiaq_set_auto_msg(cdev, 1, 0, 0);
+		snd_usb_caiaq_send_command(cdev, EP1_CMD_READ_IO, NULL, 0);
+
+		if (!wait_event_timeout(cdev->ep1_wait_queue,
+					cdev->control_state[0] != 0xff, HZ)) {
+			dev_err(dev, "Read timeout for control state\n");
+			return -EINVAL;
+		}
+
+		/* fix up some defaults */
+		if ((cdev->control_state[1] != 2) ||
+		    (cdev->control_state[2] != 3) ||
+		    (cdev->control_state[4] != 2)) {
+			cdev->control_state[1] = 2;
+			cdev->control_state[2] = 3;
+			cdev->control_state[4] = 2;
+			snd_usb_caiaq_send_command(cdev,
+				EP1_CMD_WRITE_IO, cdev->control_state, 6);
+		}
+
+		break;
+	}
+
+	if (cdev->spec.num_analog_audio_out +
+	    cdev->spec.num_analog_audio_in +
+	    cdev->spec.num_digital_audio_out +
+	    cdev->spec.num_digital_audio_in > 0) {
+		ret = snd_usb_caiaq_audio_init(cdev);
+		if (ret < 0) {
+			dev_err(dev, "Unable to set up audio system (ret=%d)\n", ret);
+			return ret;
+		}
+	}
+
+	if (cdev->spec.num_midi_in +
+	    cdev->spec.num_midi_out > 0) {
+		ret = snd_usb_caiaq_midi_init(cdev);
+		if (ret < 0) {
+			dev_err(dev, "Unable to set up MIDI system (ret=%d)\n", ret);
+			return ret;
+		}
+	}
+
+#ifdef CONFIG_SND_USB_CAIAQ_INPUT
+	ret = snd_usb_caiaq_input_init(cdev);
+	if (ret < 0 && ret != -ENODEV) {
+		dev_err(dev, "Unable to set up input system (ret=%d)\n", ret);
+		return ret;
+	}
+#endif
+
+	/* finally, register the card and all its sub-instances */
+	ret = snd_card_register(cdev->chip.card);
+	if (ret < 0) {
+		dev_err(dev, "snd_card_register() returned %d\n", ret);
+		return ret;
+	}
+
+	ret = snd_usb_caiaq_control_init(cdev);
+	if (ret < 0) {
+		dev_err(dev, "Unable to set up control system (ret=%d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void card_free(struct snd_card *card)
+{
+	struct snd_usb_caiaqdev *cdev = caiaqdev(card);
+
+#ifdef CONFIG_SND_USB_CAIAQ_INPUT
+	snd_usb_caiaq_input_free(cdev);
+#endif
+	snd_usb_caiaq_audio_free(cdev);
+	usb_put_dev(cdev->chip.dev);
+	usb_free_urb(cdev->ep1_in_urb);
+	cdev->ep1_in_urb = NULL;
+	usb_free_urb(cdev->midi_out_urb);
+	cdev->midi_out_urb = NULL;
+}
+
+static int create_card(struct usb_device *usb_dev,
+		       struct usb_interface *intf,
+		       struct snd_card **cardp)
+{
+	int devnum;
+	int err;
+	struct snd_card *card;
+	struct snd_usb_caiaqdev *cdev;
+
+	for (devnum = 0; devnum < SNDRV_CARDS; devnum++)
+		if (enable[devnum])
+			break;
+
+	if (devnum >= SNDRV_CARDS)
+		return -ENODEV;
+
+	err = snd_card_new(&intf->dev,
+			   index[devnum], id[devnum], THIS_MODULE,
+			   sizeof(struct snd_usb_caiaqdev), &card);
+	if (err < 0)
+		return err;
+
+	cdev = caiaqdev(card);
+	cdev->chip.dev = usb_get_dev(usb_dev);
+	card->private_free = card_free;
+	cdev->chip.card = card;
+	cdev->chip.usb_id = USB_ID(le16_to_cpu(usb_dev->descriptor.idVendor),
+				  le16_to_cpu(usb_dev->descriptor.idProduct));
+	spin_lock_init(&cdev->spinlock);
+
+	*cardp = card;
+	return 0;
+}
+
+static int init_card(struct snd_usb_caiaqdev *cdev)
+{
+	char *c, usbpath[32];
+	struct usb_device *usb_dev = cdev->chip.dev;
+	struct snd_card *card = cdev->chip.card;
+	struct device *dev = caiaqdev_to_dev(cdev);
+	int err, len;
+
+	if (usb_set_interface(usb_dev, 0, 1) != 0) {
+		dev_err(dev, "can't set alt interface.\n");
+		return -EIO;
+	}
+
+	cdev->ep1_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!cdev->ep1_in_urb)
+		return -ENOMEM;
+
+	cdev->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!cdev->midi_out_urb) {
+		usb_free_urb(cdev->ep1_in_urb);
+		cdev->ep1_in_urb = NULL;
+		return -ENOMEM;
+	}
+
+	usb_fill_bulk_urb(cdev->ep1_in_urb, usb_dev,
+			  usb_rcvbulkpipe(usb_dev, 0x1),
+			  cdev->ep1_in_buf, EP1_BUFSIZE,
+			  usb_ep1_command_reply_dispatch, cdev);
+
+	usb_fill_bulk_urb(cdev->midi_out_urb, usb_dev,
+			  usb_sndbulkpipe(usb_dev, 0x1),
+			  cdev->midi_out_buf, EP1_BUFSIZE,
+			  snd_usb_caiaq_midi_output_done, cdev);
+
+	/* sanity checks of EPs before actually submitting */
+	if (usb_urb_ep_type_check(cdev->ep1_in_urb) ||
+	    usb_urb_ep_type_check(cdev->midi_out_urb)) {
+		dev_err(dev, "invalid EPs\n");
+		return -EINVAL;
+	}
+
+	init_waitqueue_head(&cdev->ep1_wait_queue);
+	init_waitqueue_head(&cdev->prepare_wait_queue);
+
+	if (usb_submit_urb(cdev->ep1_in_urb, GFP_KERNEL) != 0)
+		return -EIO;
+
+	err = snd_usb_caiaq_send_command(cdev, EP1_CMD_GET_DEVICE_INFO, NULL, 0);
+	if (err)
+		goto err_kill_urb;
+
+	if (!wait_event_timeout(cdev->ep1_wait_queue, cdev->spec_received, HZ)) {
+		err = -ENODEV;
+		goto err_kill_urb;
+	}
+
+	usb_string(usb_dev, usb_dev->descriptor.iManufacturer,
+		   cdev->vendor_name, CAIAQ_USB_STR_LEN);
+
+	usb_string(usb_dev, usb_dev->descriptor.iProduct,
+		   cdev->product_name, CAIAQ_USB_STR_LEN);
+
+	strscpy(card->driver, MODNAME, sizeof(card->driver));
+	strscpy(card->shortname, cdev->product_name, sizeof(card->shortname));
+	strscpy(card->mixername, cdev->product_name, sizeof(card->mixername));
+
+	/* if the id was not passed as module option, fill it with a shortened
+	 * version of the product string which does not contain any
+	 * whitespaces */
+
+	if (*card->id == '\0') {
+		char id[sizeof(card->id)];
+
+		memset(id, 0, sizeof(id));
+
+		for (c = card->shortname, len = 0;
+			*c && len < sizeof(card->id) - 1; c++)
+			if (*c != ' ')
+				id[len++] = *c;
+
+		snd_card_set_id(card, id);
+	}
+
+	usb_make_path(usb_dev, usbpath, sizeof(usbpath));
+	scnprintf(card->longname, sizeof(card->longname), "%s %s (%s)",
+		       cdev->vendor_name, cdev->product_name, usbpath);
+
+	err = setup_card(cdev);
+	if (err < 0)
+		goto err_kill_urb;
+
+	return 0;
+
+ err_kill_urb:
+	usb_kill_urb(cdev->ep1_in_urb);
+	return err;
+}
+
+static int snd_probe(struct usb_interface *intf,
+		     const struct usb_device_id *id)
+{
+	int ret;
+	struct snd_card *card = NULL;
+	struct usb_device *usb_dev = interface_to_usbdev(intf);
+
+	ret = create_card(usb_dev, intf, &card);
+
+	if (ret < 0)
+		return ret;
+
+	usb_set_intfdata(intf, card);
+	ret = init_card(caiaqdev(card));
+	if (ret < 0) {
+		dev_err(&usb_dev->dev, "unable to init card! (ret=%d)\n", ret);
+#ifdef CONFIG_SND_USB_CAIAQ_INPUT
+		snd_usb_caiaq_input_disconnect(caiaqdev(card));
+#endif
+		snd_card_free(card);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void snd_disconnect(struct usb_interface *intf)
+{
+	struct snd_card *card = usb_get_intfdata(intf);
+	struct device *dev = intf->usb_dev;
+	struct snd_usb_caiaqdev *cdev;
+
+	if (!card)
+		return;
+
+	cdev = caiaqdev(card);
+	dev_dbg(dev, "%s(%p)\n", __func__, intf);
+
+	snd_card_disconnect(card);
+
+#ifdef CONFIG_SND_USB_CAIAQ_INPUT
+	snd_usb_caiaq_input_disconnect(cdev);
+#endif
+	snd_usb_caiaq_audio_disconnect(cdev);
+
+	usb_kill_urb(cdev->ep1_in_urb);
+	usb_kill_urb(cdev->midi_out_urb);
+
+	snd_card_free_when_closed(card);
+}
+
+
+MODULE_DEVICE_TABLE(usb, snd_usb_id_table);
+static struct usb_driver snd_usb_driver = {
+	.name 		= MODNAME,
+	.probe 		= snd_probe,
+	.disconnect	= snd_disconnect,
+	.id_table 	= snd_usb_id_table,
+};
+
+module_usb_driver(snd_usb_driver);
diff --git a/sound/usb/caiaq/device.h b/sound/usb/caiaq/device.h
new file mode 100644
index 000000000..1c6f34693
--- /dev/null
+++ b/sound/usb/caiaq/device.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef CAIAQ_DEVICE_H
+#define CAIAQ_DEVICE_H
+
+#include "../usbaudio.h"
+
+#define USB_VID_NATIVEINSTRUMENTS 0x17cc
+
+#define USB_PID_RIGKONTROL2		0x1969
+#define USB_PID_RIGKONTROL3		0x1940
+#define USB_PID_KORECONTROLLER		0x4711
+#define USB_PID_KORECONTROLLER2		0x4712
+#define USB_PID_AK1			0x0815
+#define USB_PID_AUDIO2DJ		0x041c
+#define USB_PID_AUDIO4DJ		0x0839
+#define USB_PID_AUDIO8DJ		0x1978
+#define USB_PID_SESSIONIO		0x1915
+#define USB_PID_GUITARRIGMOBILE		0x0d8d
+#define USB_PID_TRAKTORKONTROLX1	0x2305
+#define USB_PID_TRAKTORKONTROLS4	0xbaff
+#define USB_PID_TRAKTORAUDIO2		0x041d
+#define USB_PID_MASCHINECONTROLLER  0x0808
+
+#define EP1_BUFSIZE 64
+#define EP4_BUFSIZE 512
+#define CAIAQ_USB_STR_LEN 0xff
+#define MAX_STREAMS 32
+
+#define MODNAME "snd-usb-caiaq"
+
+#define EP1_CMD_GET_DEVICE_INFO	0x1
+#define EP1_CMD_READ_ERP	0x2
+#define EP1_CMD_READ_ANALOG	0x3
+#define EP1_CMD_READ_IO		0x4
+#define EP1_CMD_WRITE_IO	0x5
+#define EP1_CMD_MIDI_READ	0x6
+#define EP1_CMD_MIDI_WRITE	0x7
+#define EP1_CMD_AUDIO_PARAMS	0x9
+#define EP1_CMD_AUTO_MSG	0xb
+#define EP1_CMD_DIMM_LEDS       0xc
+
+struct caiaq_device_spec {
+	unsigned short fw_version;
+	unsigned char hw_subtype;
+	unsigned char num_erp;
+	unsigned char num_analog_in;
+	unsigned char num_digital_in;
+	unsigned char num_digital_out;
+	unsigned char num_analog_audio_out;
+	unsigned char num_analog_audio_in;
+	unsigned char num_digital_audio_out;
+	unsigned char num_digital_audio_in;
+	unsigned char num_midi_out;
+	unsigned char num_midi_in;
+	unsigned char data_alignment;
+} __packed;
+
+struct snd_usb_caiaq_cb_info;
+
+struct snd_usb_caiaqdev {
+	struct snd_usb_audio chip;
+
+	struct urb *ep1_in_urb;
+	struct urb *midi_out_urb;
+	struct urb **data_urbs_in;
+	struct urb **data_urbs_out;
+	struct snd_usb_caiaq_cb_info *data_cb_info;
+
+	unsigned char ep1_in_buf[EP1_BUFSIZE];
+	unsigned char ep1_out_buf[EP1_BUFSIZE];
+	unsigned char midi_out_buf[EP1_BUFSIZE];
+
+	struct caiaq_device_spec spec;
+	spinlock_t spinlock;
+	wait_queue_head_t ep1_wait_queue;
+	wait_queue_head_t prepare_wait_queue;
+	int spec_received, audio_parm_answer;
+	int midi_out_active;
+
+	char vendor_name[CAIAQ_USB_STR_LEN];
+	char product_name[CAIAQ_USB_STR_LEN];
+
+	int n_streams, n_audio_in, n_audio_out;
+	int streaming, first_packet, output_running;
+	int audio_in_buf_pos[MAX_STREAMS];
+	int audio_out_buf_pos[MAX_STREAMS];
+	int period_in_count[MAX_STREAMS];
+	int period_out_count[MAX_STREAMS];
+	int input_panic, output_panic, warned;
+	char *audio_in_buf, *audio_out_buf;
+	unsigned int samplerates, bpp;
+	unsigned long outurb_active_mask;
+
+	struct snd_pcm_substream *sub_playback[MAX_STREAMS];
+	struct snd_pcm_substream *sub_capture[MAX_STREAMS];
+
+	/* Controls */
+	unsigned char control_state[256];
+	unsigned char ep8_out_buf[2];
+
+	/* Linux input */
+#ifdef CONFIG_SND_USB_CAIAQ_INPUT
+	struct input_dev *input_dev;
+	char phys[64];			/* physical device path */
+	unsigned short keycode[128];
+	struct urb *ep4_in_urb;
+	unsigned char ep4_in_buf[EP4_BUFSIZE];
+#endif
+
+	/* ALSA */
+	struct snd_pcm *pcm;
+	struct snd_pcm_hardware pcm_info;
+	struct snd_rawmidi *rmidi;
+	struct snd_rawmidi_substream *midi_receive_substream;
+	struct snd_rawmidi_substream *midi_out_substream;
+};
+
+struct snd_usb_caiaq_cb_info {
+	struct snd_usb_caiaqdev *cdev;
+	int index;
+};
+
+#define caiaqdev(c) ((struct snd_usb_caiaqdev*)(c)->private_data)
+#define caiaqdev_to_dev(d)	(d->chip.card->dev)
+
+int snd_usb_caiaq_set_audio_params (struct snd_usb_caiaqdev *cdev, int rate, int depth, int bbp);
+int snd_usb_caiaq_set_auto_msg (struct snd_usb_caiaqdev *cdev, int digital, int analog, int erp);
+int snd_usb_caiaq_send_command(struct snd_usb_caiaqdev *cdev,
+			       unsigned char command,
+			       const unsigned char *buffer,
+			       int len);
+int snd_usb_caiaq_send_command_bank(struct snd_usb_caiaqdev *cdev,
+			       unsigned char command,
+			       unsigned char bank,
+			       const unsigned char *buffer,
+			       int len);
+
+#endif /* CAIAQ_DEVICE_H */
diff --git a/sound/usb/caiaq/input.c b/sound/usb/caiaq/input.c
new file mode 100644
index 000000000..8d924330c
--- /dev/null
+++ b/sound/usb/caiaq/input.c
@@ -0,0 +1,865 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (c) 2006,2007 Daniel Mack, Tim Ruetz
+*/
+
+#include <linux/device.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/usb.h>
+#include <linux/usb/input.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+
+#include "device.h"
+#include "input.h"
+
+static const unsigned short keycode_ak1[] =  { KEY_C, KEY_B, KEY_A };
+static const unsigned short keycode_rk2[] =  { KEY_1, KEY_2, KEY_3, KEY_4,
+					 KEY_5, KEY_6, KEY_7 };
+static const unsigned short keycode_rk3[] =  { KEY_1, KEY_2, KEY_3, KEY_4,
+					 KEY_5, KEY_6, KEY_7, KEY_8, KEY_9 };
+
+static const unsigned short keycode_kore[] = {
+	KEY_FN_F1,      /* "menu"               */
+	KEY_FN_F7,      /* "lcd backlight       */
+	KEY_FN_F2,      /* "control"            */
+	KEY_FN_F3,      /* "enter"              */
+	KEY_FN_F4,      /* "view"               */
+	KEY_FN_F5,      /* "esc"                */
+	KEY_FN_F6,      /* "sound"              */
+	KEY_FN_F8,      /* array spacer, never triggered. */
+	KEY_RIGHT,
+	KEY_DOWN,
+	KEY_UP,
+	KEY_LEFT,
+	KEY_SOUND,      /* "listen"             */
+	KEY_RECORD,
+	KEY_PLAYPAUSE,
+	KEY_STOP,
+	BTN_4,          /* 8 softkeys */
+	BTN_3,
+	BTN_2,
+	BTN_1,
+	BTN_8,
+	BTN_7,
+	BTN_6,
+	BTN_5,
+	KEY_BRL_DOT4,   /* touch sensitive knobs */
+	KEY_BRL_DOT3,
+	KEY_BRL_DOT2,
+	KEY_BRL_DOT1,
+	KEY_BRL_DOT8,
+	KEY_BRL_DOT7,
+	KEY_BRL_DOT6,
+	KEY_BRL_DOT5
+};
+
+#define MASCHINE_BUTTONS   (42)
+#define MASCHINE_BUTTON(X) ((X) + BTN_MISC)
+#define MASCHINE_PADS      (16)
+#define MASCHINE_PAD(X)    ((X) + ABS_PRESSURE)
+
+static const unsigned short keycode_maschine[] = {
+	MASCHINE_BUTTON(40), /* mute       */
+	MASCHINE_BUTTON(39), /* solo       */
+	MASCHINE_BUTTON(38), /* select     */
+	MASCHINE_BUTTON(37), /* duplicate  */
+	MASCHINE_BUTTON(36), /* navigate   */
+	MASCHINE_BUTTON(35), /* pad mode   */
+	MASCHINE_BUTTON(34), /* pattern    */
+	MASCHINE_BUTTON(33), /* scene      */
+	KEY_RESERVED, /* spacer */
+
+	MASCHINE_BUTTON(30), /* rec        */
+	MASCHINE_BUTTON(31), /* erase      */
+	MASCHINE_BUTTON(32), /* shift      */
+	MASCHINE_BUTTON(28), /* grid       */
+	MASCHINE_BUTTON(27), /* >          */
+	MASCHINE_BUTTON(26), /* <          */
+	MASCHINE_BUTTON(25), /* restart    */
+
+	MASCHINE_BUTTON(21), /* E          */
+	MASCHINE_BUTTON(22), /* F          */
+	MASCHINE_BUTTON(23), /* G          */
+	MASCHINE_BUTTON(24), /* H          */
+	MASCHINE_BUTTON(20), /* D          */
+	MASCHINE_BUTTON(19), /* C          */
+	MASCHINE_BUTTON(18), /* B          */
+	MASCHINE_BUTTON(17), /* A          */
+
+	MASCHINE_BUTTON(0),  /* control    */
+	MASCHINE_BUTTON(2),  /* browse     */
+	MASCHINE_BUTTON(4),  /* <          */
+	MASCHINE_BUTTON(6),  /* snap       */
+	MASCHINE_BUTTON(7),  /* autowrite  */
+	MASCHINE_BUTTON(5),  /* >          */
+	MASCHINE_BUTTON(3),  /* sampling   */
+	MASCHINE_BUTTON(1),  /* step       */
+
+	MASCHINE_BUTTON(15), /* 8 softkeys */
+	MASCHINE_BUTTON(14),
+	MASCHINE_BUTTON(13),
+	MASCHINE_BUTTON(12),
+	MASCHINE_BUTTON(11),
+	MASCHINE_BUTTON(10),
+	MASCHINE_BUTTON(9),
+	MASCHINE_BUTTON(8),
+
+	MASCHINE_BUTTON(16), /* note repeat */
+	MASCHINE_BUTTON(29)  /* play        */
+};
+
+#define KONTROLX1_INPUTS	(40)
+#define KONTROLS4_BUTTONS	(12 * 8)
+#define KONTROLS4_AXIS		(46)
+
+#define KONTROLS4_BUTTON(X)	((X) + BTN_MISC)
+#define KONTROLS4_ABS(X)	((X) + ABS_HAT0X)
+
+#define DEG90		(range / 2)
+#define DEG180		(range)
+#define DEG270		(DEG90 + DEG180)
+#define DEG360		(DEG180 * 2)
+#define HIGH_PEAK	(268)
+#define LOW_PEAK	(-7)
+
+/* some of these devices have endless rotation potentiometers
+ * built in which use two tapers, 90 degrees phase shifted.
+ * this algorithm decodes them to one single value, ranging
+ * from 0 to 999 */
+static unsigned int decode_erp(unsigned char a, unsigned char b)
+{
+	int weight_a, weight_b;
+	int pos_a, pos_b;
+	int ret;
+	int range = HIGH_PEAK - LOW_PEAK;
+	int mid_value = (HIGH_PEAK + LOW_PEAK) / 2;
+
+	weight_b = abs(mid_value - a) - (range / 2 - 100) / 2;
+
+	if (weight_b < 0)
+		weight_b = 0;
+
+	if (weight_b > 100)
+		weight_b = 100;
+
+	weight_a = 100 - weight_b;
+
+	if (a < mid_value) {
+		/* 0..90 and 270..360 degrees */
+		pos_b = b - LOW_PEAK + DEG270;
+		if (pos_b >= DEG360)
+			pos_b -= DEG360;
+	} else
+		/* 90..270 degrees */
+		pos_b = HIGH_PEAK - b + DEG90;
+
+
+	if (b > mid_value)
+		/* 0..180 degrees */
+		pos_a = a - LOW_PEAK;
+	else
+		/* 180..360 degrees */
+		pos_a = HIGH_PEAK - a + DEG180;
+
+	/* interpolate both slider values, depending on weight factors */
+	/* 0..99 x DEG360 */
+	ret = pos_a * weight_a + pos_b * weight_b;
+
+	/* normalize to 0..999 */
+	ret *= 10;
+	ret /= DEG360;
+
+	if (ret < 0)
+		ret += 1000;
+
+	if (ret >= 1000)
+		ret -= 1000;
+
+	return ret;
+}
+
+#undef DEG90
+#undef DEG180
+#undef DEG270
+#undef DEG360
+#undef HIGH_PEAK
+#undef LOW_PEAK
+
+static inline void snd_caiaq_input_report_abs(struct snd_usb_caiaqdev *cdev,
+					      int axis, const unsigned char *buf,
+					      int offset)
+{
+	input_report_abs(cdev->input_dev, axis,
+			 (buf[offset * 2] << 8) | buf[offset * 2 + 1]);
+}
+
+static void snd_caiaq_input_read_analog(struct snd_usb_caiaqdev *cdev,
+					const unsigned char *buf,
+					unsigned int len)
+{
+	struct input_dev *input_dev = cdev->input_dev;
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL2):
+		if (len < 6)
+			return;
+		snd_caiaq_input_report_abs(cdev, ABS_X, buf, 2);
+		snd_caiaq_input_report_abs(cdev, ABS_Y, buf, 0);
+		snd_caiaq_input_report_abs(cdev, ABS_Z, buf, 1);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL3):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER2):
+		if (len < 6)
+			return;
+		snd_caiaq_input_report_abs(cdev, ABS_X, buf, 0);
+		snd_caiaq_input_report_abs(cdev, ABS_Y, buf, 1);
+		snd_caiaq_input_report_abs(cdev, ABS_Z, buf, 2);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+		if (len < 16)
+			return;
+		snd_caiaq_input_report_abs(cdev, ABS_HAT0X, buf, 4);
+		snd_caiaq_input_report_abs(cdev, ABS_HAT0Y, buf, 2);
+		snd_caiaq_input_report_abs(cdev, ABS_HAT1X, buf, 6);
+		snd_caiaq_input_report_abs(cdev, ABS_HAT1Y, buf, 1);
+		snd_caiaq_input_report_abs(cdev, ABS_HAT2X, buf, 7);
+		snd_caiaq_input_report_abs(cdev, ABS_HAT2Y, buf, 0);
+		snd_caiaq_input_report_abs(cdev, ABS_HAT3X, buf, 5);
+		snd_caiaq_input_report_abs(cdev, ABS_HAT3Y, buf, 3);
+		break;
+	}
+
+	input_sync(input_dev);
+}
+
+static void snd_caiaq_input_read_erp(struct snd_usb_caiaqdev *cdev,
+				     const char *buf, unsigned int len)
+{
+	struct input_dev *input_dev = cdev->input_dev;
+	int i;
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AK1):
+		if (len < 2)
+			return;
+		i = decode_erp(buf[0], buf[1]);
+		input_report_abs(input_dev, ABS_X, i);
+		input_sync(input_dev);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER2):
+		if (len < 16)
+			return;
+		i = decode_erp(buf[7], buf[5]);
+		input_report_abs(input_dev, ABS_HAT0X, i);
+		i = decode_erp(buf[12], buf[14]);
+		input_report_abs(input_dev, ABS_HAT0Y, i);
+		i = decode_erp(buf[15], buf[13]);
+		input_report_abs(input_dev, ABS_HAT1X, i);
+		i = decode_erp(buf[0], buf[2]);
+		input_report_abs(input_dev, ABS_HAT1Y, i);
+		i = decode_erp(buf[3], buf[1]);
+		input_report_abs(input_dev, ABS_HAT2X, i);
+		i = decode_erp(buf[8], buf[10]);
+		input_report_abs(input_dev, ABS_HAT2Y, i);
+		i = decode_erp(buf[11], buf[9]);
+		input_report_abs(input_dev, ABS_HAT3X, i);
+		i = decode_erp(buf[4], buf[6]);
+		input_report_abs(input_dev, ABS_HAT3Y, i);
+		input_sync(input_dev);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER):
+		if (len < 22)
+			return;
+		/* 4 under the left screen */
+		input_report_abs(input_dev, ABS_HAT0X, decode_erp(buf[21], buf[20]));
+		input_report_abs(input_dev, ABS_HAT0Y, decode_erp(buf[15], buf[14]));
+		input_report_abs(input_dev, ABS_HAT1X, decode_erp(buf[9],  buf[8]));
+		input_report_abs(input_dev, ABS_HAT1Y, decode_erp(buf[3],  buf[2]));
+
+		/* 4 under the right screen */
+		input_report_abs(input_dev, ABS_HAT2X, decode_erp(buf[19], buf[18]));
+		input_report_abs(input_dev, ABS_HAT2Y, decode_erp(buf[13], buf[12]));
+		input_report_abs(input_dev, ABS_HAT3X, decode_erp(buf[7],  buf[6]));
+		input_report_abs(input_dev, ABS_HAT3Y, decode_erp(buf[1],  buf[0]));
+
+		/* volume */
+		input_report_abs(input_dev, ABS_RX, decode_erp(buf[17], buf[16]));
+		/* tempo */
+		input_report_abs(input_dev, ABS_RY, decode_erp(buf[11], buf[10]));
+		/* swing */
+		input_report_abs(input_dev, ABS_RZ, decode_erp(buf[5],  buf[4]));
+
+		input_sync(input_dev);
+		break;
+	}
+}
+
+static void snd_caiaq_input_read_io(struct snd_usb_caiaqdev *cdev,
+				    unsigned char *buf, unsigned int len)
+{
+	struct input_dev *input_dev = cdev->input_dev;
+	unsigned short *keycode = input_dev->keycode;
+	int i;
+
+	if (!keycode)
+		return;
+
+	if (input_dev->id.product == USB_PID_RIGKONTROL2)
+		for (i = 0; i < len; i++)
+			buf[i] = ~buf[i];
+
+	for (i = 0; i < input_dev->keycodemax && i < len * 8; i++)
+		input_report_key(input_dev, keycode[i],
+				 buf[i / 8] & (1 << (i % 8)));
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER2):
+		if (len < 5)
+			return;
+		input_report_abs(cdev->input_dev, ABS_MISC, 255 - buf[4]);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+		if (len < 7)
+			return;
+		/* rotary encoders */
+		input_report_abs(cdev->input_dev, ABS_X, buf[5] & 0xf);
+		input_report_abs(cdev->input_dev, ABS_Y, buf[5] >> 4);
+		input_report_abs(cdev->input_dev, ABS_Z, buf[6] & 0xf);
+		input_report_abs(cdev->input_dev, ABS_MISC, buf[6] >> 4);
+		break;
+	}
+
+	input_sync(input_dev);
+}
+
+#define TKS4_MSGBLOCK_SIZE	16
+
+static void snd_usb_caiaq_tks4_dispatch(struct snd_usb_caiaqdev *cdev,
+					const unsigned char *buf,
+					unsigned int len)
+{
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	while (len >= TKS4_MSGBLOCK_SIZE) {
+		unsigned int i, block_id = (buf[0] << 8) | buf[1];
+
+		switch (block_id) {
+		case 0:
+			/* buttons */
+			for (i = 0; i < KONTROLS4_BUTTONS; i++)
+				input_report_key(cdev->input_dev, KONTROLS4_BUTTON(i),
+						 (buf[4 + (i / 8)] >> (i % 8)) & 1);
+			break;
+
+		case 1:
+			/* left wheel */
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(36), buf[9] | ((buf[8] & 0x3) << 8));
+			/* right wheel */
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(37), buf[13] | ((buf[12] & 0x3) << 8));
+
+			/* rotary encoders */
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(38), buf[3] & 0xf);
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(39), buf[4] >> 4);
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(40), buf[4] & 0xf);
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(41), buf[5] >> 4);
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(42), buf[5] & 0xf);
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(43), buf[6] >> 4);
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(44), buf[6] & 0xf);
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(45), buf[7] >> 4);
+			input_report_abs(cdev->input_dev, KONTROLS4_ABS(46), buf[7] & 0xf);
+
+			break;
+		case 2:
+			/* Volume Fader Channel D */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(0), buf, 1);
+			/* Volume Fader Channel B */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(1), buf, 2);
+			/* Volume Fader Channel A */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(2), buf, 3);
+			/* Volume Fader Channel C */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(3), buf, 4);
+			/* Loop Volume */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(4), buf, 6);
+			/* Crossfader */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(7), buf, 7);
+
+			break;
+
+		case 3:
+			/* Tempo Fader R */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(6), buf, 3);
+			/* Tempo Fader L */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(5), buf, 4);
+			/* Mic Volume */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(8), buf, 6);
+			/* Cue Mix */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(9), buf, 7);
+
+			break;
+
+		case 4:
+			/* Wheel distance sensor L */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(10), buf, 1);
+			/* Wheel distance sensor R */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(11), buf, 2);
+			/* Channel D EQ - Filter */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(12), buf, 3);
+			/* Channel D EQ - Low */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(13), buf, 4);
+			/* Channel D EQ - Mid */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(14), buf, 5);
+			/* Channel D EQ - Hi */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(15), buf, 6);
+			/* FX2 - dry/wet */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(16), buf, 7);
+
+			break;
+
+		case 5:
+			/* FX2 - 1 */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(17), buf, 1);
+			/* FX2 - 2 */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(18), buf, 2);
+			/* FX2 - 3 */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(19), buf, 3);
+			/* Channel B EQ - Filter */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(20), buf, 4);
+			/* Channel B EQ - Low */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(21), buf, 5);
+			/* Channel B EQ - Mid */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(22), buf, 6);
+			/* Channel B EQ - Hi */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(23), buf, 7);
+
+			break;
+
+		case 6:
+			/* Channel A EQ - Filter */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(24), buf, 1);
+			/* Channel A EQ - Low */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(25), buf, 2);
+			/* Channel A EQ - Mid */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(26), buf, 3);
+			/* Channel A EQ - Hi */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(27), buf, 4);
+			/* Channel C EQ - Filter */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(28), buf, 5);
+			/* Channel C EQ - Low */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(29), buf, 6);
+			/* Channel C EQ - Mid */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(30), buf, 7);
+
+			break;
+
+		case 7:
+			/* Channel C EQ - Hi */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(31), buf, 1);
+			/* FX1 - wet/dry */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(32), buf, 2);
+			/* FX1 - 1 */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(33), buf, 3);
+			/* FX1 - 2 */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(34), buf, 4);
+			/* FX1 - 3 */
+			snd_caiaq_input_report_abs(cdev, KONTROLS4_ABS(35), buf, 5);
+
+			break;
+
+		default:
+			dev_dbg(dev, "%s(): bogus block (id %d)\n",
+				__func__, block_id);
+			return;
+		}
+
+		len -= TKS4_MSGBLOCK_SIZE;
+		buf += TKS4_MSGBLOCK_SIZE;
+	}
+
+	input_sync(cdev->input_dev);
+}
+
+#define MASCHINE_MSGBLOCK_SIZE 2
+
+static void snd_usb_caiaq_maschine_dispatch(struct snd_usb_caiaqdev *cdev,
+					const unsigned char *buf,
+					unsigned int len)
+{
+	unsigned int i, pad_id;
+	__le16 *pressure = (__le16 *) buf;
+
+	for (i = 0; i < MASCHINE_PADS; i++) {
+		pad_id = le16_to_cpu(*pressure) >> 12;
+		input_report_abs(cdev->input_dev, MASCHINE_PAD(pad_id),
+				 le16_to_cpu(*pressure) & 0xfff);
+		pressure++;
+	}
+
+	input_sync(cdev->input_dev);
+}
+
+static void snd_usb_caiaq_ep4_reply_dispatch(struct urb *urb)
+{
+	struct snd_usb_caiaqdev *cdev = urb->context;
+	unsigned char *buf = urb->transfer_buffer;
+	struct device *dev = &urb->dev->dev;
+	int ret;
+
+	if (urb->status || !cdev || urb != cdev->ep4_in_urb)
+		return;
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+		if (urb->actual_length < 24)
+			goto requeue;
+
+		if (buf[0] & 0x3)
+			snd_caiaq_input_read_io(cdev, buf + 1, 7);
+
+		if (buf[0] & 0x4)
+			snd_caiaq_input_read_analog(cdev, buf + 8, 16);
+
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLS4):
+		snd_usb_caiaq_tks4_dispatch(cdev, buf, urb->actual_length);
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER):
+		if (urb->actual_length < (MASCHINE_PADS * MASCHINE_MSGBLOCK_SIZE))
+			goto requeue;
+
+		snd_usb_caiaq_maschine_dispatch(cdev, buf, urb->actual_length);
+		break;
+	}
+
+requeue:
+	cdev->ep4_in_urb->actual_length = 0;
+	ret = usb_submit_urb(cdev->ep4_in_urb, GFP_ATOMIC);
+	if (ret < 0)
+		dev_err(dev, "unable to submit urb. OOM!?\n");
+}
+
+static int snd_usb_caiaq_input_open(struct input_dev *idev)
+{
+	struct snd_usb_caiaqdev *cdev = input_get_drvdata(idev);
+
+	if (!cdev)
+		return -EINVAL;
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLS4):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER):
+		if (usb_submit_urb(cdev->ep4_in_urb, GFP_KERNEL) != 0)
+			return -EIO;
+		break;
+	}
+
+	return 0;
+}
+
+static void snd_usb_caiaq_input_close(struct input_dev *idev)
+{
+	struct snd_usb_caiaqdev *cdev = input_get_drvdata(idev);
+
+	if (!cdev)
+		return;
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLS4):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER):
+		usb_kill_urb(cdev->ep4_in_urb);
+		break;
+	}
+}
+
+void snd_usb_caiaq_input_dispatch(struct snd_usb_caiaqdev *cdev,
+				  char *buf,
+				  unsigned int len)
+{
+	if (!cdev->input_dev || len < 1)
+		return;
+
+	switch (buf[0]) {
+	case EP1_CMD_READ_ANALOG:
+		snd_caiaq_input_read_analog(cdev, buf + 1, len - 1);
+		break;
+	case EP1_CMD_READ_ERP:
+		snd_caiaq_input_read_erp(cdev, buf + 1, len - 1);
+		break;
+	case EP1_CMD_READ_IO:
+		snd_caiaq_input_read_io(cdev, buf + 1, len - 1);
+		break;
+	}
+}
+
+int snd_usb_caiaq_input_init(struct snd_usb_caiaqdev *cdev)
+{
+	struct usb_device *usb_dev = cdev->chip.dev;
+	struct input_dev *input;
+	int i, ret = 0;
+
+	input = input_allocate_device();
+	if (!input)
+		return -ENOMEM;
+
+	usb_make_path(usb_dev, cdev->phys, sizeof(cdev->phys));
+	strlcat(cdev->phys, "/input0", sizeof(cdev->phys));
+
+	input->name = cdev->product_name;
+	input->phys = cdev->phys;
+	usb_to_input_id(usb_dev, &input->id);
+	input->dev.parent = &usb_dev->dev;
+
+	input_set_drvdata(input, cdev);
+
+	switch (cdev->chip.usb_id) {
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL2):
+		input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+		input->absbit[0] = BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) |
+			BIT_MASK(ABS_Z);
+		BUILD_BUG_ON(sizeof(cdev->keycode) < sizeof(keycode_rk2));
+		memcpy(cdev->keycode, keycode_rk2, sizeof(keycode_rk2));
+		input->keycodemax = ARRAY_SIZE(keycode_rk2);
+		input_set_abs_params(input, ABS_X, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_Y, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_Z, 0, 4096, 0, 10);
+		snd_usb_caiaq_set_auto_msg(cdev, 1, 10, 0);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_RIGKONTROL3):
+		input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+		input->absbit[0] = BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) |
+			BIT_MASK(ABS_Z);
+		BUILD_BUG_ON(sizeof(cdev->keycode) < sizeof(keycode_rk3));
+		memcpy(cdev->keycode, keycode_rk3, sizeof(keycode_rk3));
+		input->keycodemax = ARRAY_SIZE(keycode_rk3);
+		input_set_abs_params(input, ABS_X, 0, 1024, 0, 10);
+		input_set_abs_params(input, ABS_Y, 0, 1024, 0, 10);
+		input_set_abs_params(input, ABS_Z, 0, 1024, 0, 10);
+		snd_usb_caiaq_set_auto_msg(cdev, 1, 10, 0);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AK1):
+		input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+		input->absbit[0] = BIT_MASK(ABS_X);
+		BUILD_BUG_ON(sizeof(cdev->keycode) < sizeof(keycode_ak1));
+		memcpy(cdev->keycode, keycode_ak1, sizeof(keycode_ak1));
+		input->keycodemax = ARRAY_SIZE(keycode_ak1);
+		input_set_abs_params(input, ABS_X, 0, 999, 0, 10);
+		snd_usb_caiaq_set_auto_msg(cdev, 1, 0, 5);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_KORECONTROLLER2):
+		input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+		input->absbit[0] = BIT_MASK(ABS_HAT0X) | BIT_MASK(ABS_HAT0Y) |
+				   BIT_MASK(ABS_HAT1X) | BIT_MASK(ABS_HAT1Y) |
+				   BIT_MASK(ABS_HAT2X) | BIT_MASK(ABS_HAT2Y) |
+				   BIT_MASK(ABS_HAT3X) | BIT_MASK(ABS_HAT3Y) |
+				   BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) |
+				   BIT_MASK(ABS_Z);
+		input->absbit[BIT_WORD(ABS_MISC)] |= BIT_MASK(ABS_MISC);
+		BUILD_BUG_ON(sizeof(cdev->keycode) < sizeof(keycode_kore));
+		memcpy(cdev->keycode, keycode_kore, sizeof(keycode_kore));
+		input->keycodemax = ARRAY_SIZE(keycode_kore);
+		input_set_abs_params(input, ABS_HAT0X, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT0Y, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT1X, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT1Y, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT2X, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT2Y, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT3X, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT3Y, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_X, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_Y, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_Z, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_MISC, 0, 255, 0, 1);
+		snd_usb_caiaq_set_auto_msg(cdev, 1, 10, 5);
+		break;
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
+		input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+		input->absbit[0] = BIT_MASK(ABS_HAT0X) | BIT_MASK(ABS_HAT0Y) |
+				   BIT_MASK(ABS_HAT1X) | BIT_MASK(ABS_HAT1Y) |
+				   BIT_MASK(ABS_HAT2X) | BIT_MASK(ABS_HAT2Y) |
+				   BIT_MASK(ABS_HAT3X) | BIT_MASK(ABS_HAT3Y) |
+				   BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) |
+				   BIT_MASK(ABS_Z);
+		input->absbit[BIT_WORD(ABS_MISC)] |= BIT_MASK(ABS_MISC);
+		BUILD_BUG_ON(sizeof(cdev->keycode) < KONTROLX1_INPUTS);
+		for (i = 0; i < KONTROLX1_INPUTS; i++)
+			cdev->keycode[i] = BTN_MISC + i;
+		input->keycodemax = KONTROLX1_INPUTS;
+
+		/* analog potentiometers */
+		input_set_abs_params(input, ABS_HAT0X, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_HAT0Y, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_HAT1X, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_HAT1Y, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_HAT2X, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_HAT2Y, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_HAT3X, 0, 4096, 0, 10);
+		input_set_abs_params(input, ABS_HAT3Y, 0, 4096, 0, 10);
+
+		/* rotary encoders */
+		input_set_abs_params(input, ABS_X, 0, 0xf, 0, 1);
+		input_set_abs_params(input, ABS_Y, 0, 0xf, 0, 1);
+		input_set_abs_params(input, ABS_Z, 0, 0xf, 0, 1);
+		input_set_abs_params(input, ABS_MISC, 0, 0xf, 0, 1);
+
+		cdev->ep4_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!cdev->ep4_in_urb) {
+			ret = -ENOMEM;
+			goto exit_free_idev;
+		}
+
+		usb_fill_bulk_urb(cdev->ep4_in_urb, usb_dev,
+				  usb_rcvbulkpipe(usb_dev, 0x4),
+				  cdev->ep4_in_buf, EP4_BUFSIZE,
+				  snd_usb_caiaq_ep4_reply_dispatch, cdev);
+		ret = usb_urb_ep_type_check(cdev->ep4_in_urb);
+		if (ret < 0)
+			goto exit_free_idev;
+
+		snd_usb_caiaq_set_auto_msg(cdev, 1, 10, 5);
+
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLS4):
+		input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+		BUILD_BUG_ON(sizeof(cdev->keycode) < KONTROLS4_BUTTONS);
+		for (i = 0; i < KONTROLS4_BUTTONS; i++)
+			cdev->keycode[i] = KONTROLS4_BUTTON(i);
+		input->keycodemax = KONTROLS4_BUTTONS;
+
+		for (i = 0; i < KONTROLS4_AXIS; i++) {
+			int axis = KONTROLS4_ABS(i);
+			input->absbit[BIT_WORD(axis)] |= BIT_MASK(axis);
+		}
+
+		/* 36 analog potentiometers and faders */
+		for (i = 0; i < 36; i++)
+			input_set_abs_params(input, KONTROLS4_ABS(i), 0, 0xfff, 0, 10);
+
+		/* 2 encoder wheels */
+		input_set_abs_params(input, KONTROLS4_ABS(36), 0, 0x3ff, 0, 1);
+		input_set_abs_params(input, KONTROLS4_ABS(37), 0, 0x3ff, 0, 1);
+
+		/* 9 rotary encoders */
+		for (i = 0; i < 9; i++)
+			input_set_abs_params(input, KONTROLS4_ABS(38+i), 0, 0xf, 0, 1);
+
+		cdev->ep4_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!cdev->ep4_in_urb) {
+			ret = -ENOMEM;
+			goto exit_free_idev;
+		}
+
+		usb_fill_bulk_urb(cdev->ep4_in_urb, usb_dev,
+				  usb_rcvbulkpipe(usb_dev, 0x4),
+				  cdev->ep4_in_buf, EP4_BUFSIZE,
+				  snd_usb_caiaq_ep4_reply_dispatch, cdev);
+		ret = usb_urb_ep_type_check(cdev->ep4_in_urb);
+		if (ret < 0)
+			goto exit_free_idev;
+
+		snd_usb_caiaq_set_auto_msg(cdev, 1, 10, 5);
+
+		break;
+
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_MASCHINECONTROLLER):
+		input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+		input->absbit[0] = BIT_MASK(ABS_HAT0X) | BIT_MASK(ABS_HAT0Y) |
+			BIT_MASK(ABS_HAT1X) | BIT_MASK(ABS_HAT1Y) |
+			BIT_MASK(ABS_HAT2X) | BIT_MASK(ABS_HAT2Y) |
+			BIT_MASK(ABS_HAT3X) | BIT_MASK(ABS_HAT3Y) |
+			BIT_MASK(ABS_RX) | BIT_MASK(ABS_RY) |
+			BIT_MASK(ABS_RZ);
+
+		BUILD_BUG_ON(sizeof(cdev->keycode) < sizeof(keycode_maschine));
+		memcpy(cdev->keycode, keycode_maschine, sizeof(keycode_maschine));
+		input->keycodemax = ARRAY_SIZE(keycode_maschine);
+
+		for (i = 0; i < MASCHINE_PADS; i++) {
+			input->absbit[0] |= MASCHINE_PAD(i);
+			input_set_abs_params(input, MASCHINE_PAD(i), 0, 0xfff, 5, 10);
+		}
+
+		input_set_abs_params(input, ABS_HAT0X, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT0Y, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT1X, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT1Y, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT2X, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT2Y, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT3X, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_HAT3Y, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_RX, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_RY, 0, 999, 0, 10);
+		input_set_abs_params(input, ABS_RZ, 0, 999, 0, 10);
+
+		cdev->ep4_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!cdev->ep4_in_urb) {
+			ret = -ENOMEM;
+			goto exit_free_idev;
+		}
+
+		usb_fill_bulk_urb(cdev->ep4_in_urb, usb_dev,
+				  usb_rcvbulkpipe(usb_dev, 0x4),
+				  cdev->ep4_in_buf, EP4_BUFSIZE,
+				  snd_usb_caiaq_ep4_reply_dispatch, cdev);
+		ret = usb_urb_ep_type_check(cdev->ep4_in_urb);
+		if (ret < 0)
+			goto exit_free_idev;
+
+		snd_usb_caiaq_set_auto_msg(cdev, 1, 10, 5);
+		break;
+
+	default:
+		/* no input methods supported on this device */
+		ret = -ENODEV;
+		goto exit_free_idev;
+	}
+
+	input->open = snd_usb_caiaq_input_open;
+	input->close = snd_usb_caiaq_input_close;
+	input->keycode = cdev->keycode;
+	input->keycodesize = sizeof(unsigned short);
+	for (i = 0; i < input->keycodemax; i++)
+		__set_bit(cdev->keycode[i], input->keybit);
+
+	cdev->input_dev = input;
+
+	ret = input_register_device(input);
+	if (ret < 0)
+		goto exit_free_idev;
+
+	return 0;
+
+exit_free_idev:
+	input_free_device(input);
+	cdev->input_dev = NULL;
+	return ret;
+}
+
+void snd_usb_caiaq_input_disconnect(struct snd_usb_caiaqdev *cdev)
+{
+	if (!cdev || !cdev->input_dev)
+		return;
+
+	usb_kill_urb(cdev->ep4_in_urb);
+	input_unregister_device(cdev->input_dev);
+}
+
+void snd_usb_caiaq_input_free(struct snd_usb_caiaqdev *cdev)
+{
+	if (!cdev || !cdev->input_dev)
+		return;
+
+	usb_free_urb(cdev->ep4_in_urb);
+	cdev->ep4_in_urb = NULL;
+	cdev->input_dev = NULL;
+}
diff --git a/sound/usb/caiaq/input.h b/sound/usb/caiaq/input.h
new file mode 100644
index 000000000..fbe267f85
--- /dev/null
+++ b/sound/usb/caiaq/input.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef CAIAQ_INPUT_H
+#define CAIAQ_INPUT_H
+
+void snd_usb_caiaq_input_dispatch(struct snd_usb_caiaqdev *cdev, char *buf, unsigned int len);
+int snd_usb_caiaq_input_init(struct snd_usb_caiaqdev *cdev);
+void snd_usb_caiaq_input_disconnect(struct snd_usb_caiaqdev *cdev);
+void snd_usb_caiaq_input_free(struct snd_usb_caiaqdev *cdev);
+
+#endif
diff --git a/sound/usb/caiaq/midi.c b/sound/usb/caiaq/midi.c
new file mode 100644
index 000000000..18529484c
--- /dev/null
+++ b/sound/usb/caiaq/midi.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (c) 2006,2007 Daniel Mack
+*/
+
+#include <linux/device.h>
+#include <linux/usb.h>
+#include <linux/gfp.h>
+#include <sound/rawmidi.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+
+#include "device.h"
+#include "midi.h"
+
+static int snd_usb_caiaq_midi_input_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int snd_usb_caiaq_midi_input_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static void snd_usb_caiaq_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+	struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;
+
+	if (!cdev)
+		return;
+
+	cdev->midi_receive_substream = up ? substream : NULL;
+}
+
+
+static int snd_usb_caiaq_midi_output_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int snd_usb_caiaq_midi_output_close(struct snd_rawmidi_substream *substream)
+{
+	struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;
+	if (cdev->midi_out_active) {
+		usb_kill_urb(cdev->midi_out_urb);
+		cdev->midi_out_active = 0;
+	}
+	return 0;
+}
+
+static void snd_usb_caiaq_midi_send(struct snd_usb_caiaqdev *cdev,
+				    struct snd_rawmidi_substream *substream)
+{
+	int len, ret;
+	struct device *dev = caiaqdev_to_dev(cdev);
+
+	cdev->midi_out_buf[0] = EP1_CMD_MIDI_WRITE;
+	cdev->midi_out_buf[1] = 0; /* port */
+	len = snd_rawmidi_transmit(substream, cdev->midi_out_buf + 3,
+				   EP1_BUFSIZE - 3);
+
+	if (len <= 0)
+		return;
+
+	cdev->midi_out_buf[2] = len;
+	cdev->midi_out_urb->transfer_buffer_length = len+3;
+
+	ret = usb_submit_urb(cdev->midi_out_urb, GFP_ATOMIC);
+	if (ret < 0)
+		dev_err(dev,
+			"snd_usb_caiaq_midi_send(%p): usb_submit_urb() failed,"
+			"ret=%d, len=%d\n", substream, ret, len);
+	else
+		cdev->midi_out_active = 1;
+}
+
+static void snd_usb_caiaq_midi_output_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+	struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;
+
+	if (up) {
+		cdev->midi_out_substream = substream;
+		if (!cdev->midi_out_active)
+			snd_usb_caiaq_midi_send(cdev, substream);
+	} else {
+		cdev->midi_out_substream = NULL;
+	}
+}
+
+
+static const struct snd_rawmidi_ops snd_usb_caiaq_midi_output =
+{
+	.open =		snd_usb_caiaq_midi_output_open,
+	.close =	snd_usb_caiaq_midi_output_close,
+	.trigger =      snd_usb_caiaq_midi_output_trigger,
+};
+
+static const struct snd_rawmidi_ops snd_usb_caiaq_midi_input =
+{
+	.open =		snd_usb_caiaq_midi_input_open,
+	.close =	snd_usb_caiaq_midi_input_close,
+	.trigger =      snd_usb_caiaq_midi_input_trigger,
+};
+
+void snd_usb_caiaq_midi_handle_input(struct snd_usb_caiaqdev *cdev,
+				     int port, const char *buf, int len)
+{
+	if (!cdev->midi_receive_substream)
+		return;
+
+	snd_rawmidi_receive(cdev->midi_receive_substream, buf, len);
+}
+
+int snd_usb_caiaq_midi_init(struct snd_usb_caiaqdev *device)
+{
+	int ret;
+	struct snd_rawmidi *rmidi;
+
+	ret = snd_rawmidi_new(device->chip.card, device->product_name, 0,
+					device->spec.num_midi_out,
+					device->spec.num_midi_in,
+					&rmidi);
+
+	if (ret < 0)
+		return ret;
+
+	strscpy(rmidi->name, device->product_name, sizeof(rmidi->name));
+
+	rmidi->info_flags = SNDRV_RAWMIDI_INFO_DUPLEX;
+	rmidi->private_data = device;
+
+	if (device->spec.num_midi_out > 0) {
+		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT;
+		snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+				    &snd_usb_caiaq_midi_output);
+	}
+
+	if (device->spec.num_midi_in > 0) {
+		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
+		snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+				    &snd_usb_caiaq_midi_input);
+	}
+
+	device->rmidi = rmidi;
+
+	return 0;
+}
+
+void snd_usb_caiaq_midi_output_done(struct urb* urb)
+{
+	struct snd_usb_caiaqdev *cdev = urb->context;
+
+	cdev->midi_out_active = 0;
+	if (urb->status != 0)
+		return;
+
+	if (!cdev->midi_out_substream)
+		return;
+
+	snd_usb_caiaq_midi_send(cdev, cdev->midi_out_substream);
+}
diff --git a/sound/usb/caiaq/midi.h b/sound/usb/caiaq/midi.h
new file mode 100644
index 000000000..a6ae0c224
--- /dev/null
+++ b/sound/usb/caiaq/midi.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef CAIAQ_MIDI_H
+#define CAIAQ_MIDI_H
+
+int snd_usb_caiaq_midi_init(struct snd_usb_caiaqdev *cdev);
+void snd_usb_caiaq_midi_handle_input(struct snd_usb_caiaqdev *cdev,
+				     int port, const char *buf, int len);
+void snd_usb_caiaq_midi_output_done(struct urb *urb);
+
+#endif /* CAIAQ_MIDI_H */
diff --git a/sound/usb/card.c b/sound/usb/card.c
new file mode 100644
index 000000000..9307da95e
--- /dev/null
+++ b/sound/usb/card.c
@@ -0,0 +1,1350 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   (Tentative) USB Audio Driver for ALSA
+ *
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
+ *
+ *   Many codes borrowed from audio.c by
+ *	    Alan Cox (alan@lxorguk.ukuu.org.uk)
+ *	    Thomas Sailer (sailer@ife.ee.ethz.ch)
+ *
+ *   Audio Class 3.0 support by Ruslan Bilovol <ruslan.bilovol@gmail.com>
+ *
+ *  NOTES:
+ *
+ *   - the linked URBs would be preferred but not used so far because of
+ *     the instability of unlinking.
+ *   - type II is not supported properly.  there is no device which supports
+ *     this type *correctly*.  SB extigy looks as if it supports, but it's
+ *     indeed an AC3 stream packed in SPDIF frames (i.e. no real AC3 stream).
+ */
+
+
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/usb.h>
+#include <linux/moduleparam.h>
+#include <linux/mutex.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+#include <linux/module.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/initval.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "midi.h"
+#include "midi2.h"
+#include "mixer.h"
+#include "proc.h"
+#include "quirks.h"
+#include "endpoint.h"
+#include "helper.h"
+#include "pcm.h"
+#include "format.h"
+#include "power.h"
+#include "stream.h"
+#include "media.h"
+
+MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
+MODULE_DESCRIPTION("USB Audio");
+MODULE_LICENSE("GPL");
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;/* Enable this card */
+/* Vendor/product IDs for this card */
+static int vid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
+static int pid[SNDRV_CARDS] = { [0 ... (SNDRV_CARDS-1)] = -1 };
+static int device_setup[SNDRV_CARDS]; /* device parameter for this card */
+static bool ignore_ctl_error;
+static bool autoclock = true;
+static bool lowlatency = true;
+static char *quirk_alias[SNDRV_CARDS];
+static char *delayed_register[SNDRV_CARDS];
+static bool implicit_fb[SNDRV_CARDS];
+static char *quirk_flags[SNDRV_CARDS];
+
+bool snd_usb_use_vmalloc = true;
+bool snd_usb_skip_validation;
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string for the USB audio adapter.");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "Enable USB audio adapter.");
+module_param_array(vid, int, NULL, 0444);
+MODULE_PARM_DESC(vid, "Vendor ID for the USB audio device.");
+module_param_array(pid, int, NULL, 0444);
+MODULE_PARM_DESC(pid, "Product ID for the USB audio device.");
+module_param_array(device_setup, int, NULL, 0444);
+MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
+module_param(ignore_ctl_error, bool, 0444);
+MODULE_PARM_DESC(ignore_ctl_error,
+		 "Ignore errors from USB controller for mixer interfaces.");
+module_param(autoclock, bool, 0444);
+MODULE_PARM_DESC(autoclock, "Enable auto-clock selection for UAC2 devices (default: yes).");
+module_param(lowlatency, bool, 0444);
+MODULE_PARM_DESC(lowlatency, "Enable low latency playback (default: yes).");
+module_param_array(quirk_alias, charp, NULL, 0444);
+MODULE_PARM_DESC(quirk_alias, "Quirk aliases, e.g. 0123abcd:5678beef.");
+module_param_array(delayed_register, charp, NULL, 0444);
+MODULE_PARM_DESC(delayed_register, "Quirk for delayed registration, given by id:iface, e.g. 0123abcd:4.");
+module_param_array(implicit_fb, bool, NULL, 0444);
+MODULE_PARM_DESC(implicit_fb, "Apply generic implicit feedback sync mode.");
+module_param_named(use_vmalloc, snd_usb_use_vmalloc, bool, 0444);
+MODULE_PARM_DESC(use_vmalloc, "Use vmalloc for PCM intermediate buffers (default: yes).");
+module_param_named(skip_validation, snd_usb_skip_validation, bool, 0444);
+MODULE_PARM_DESC(skip_validation, "Skip unit descriptor validation (default: no).");
+
+/* protects quirk_flags */
+static DEFINE_MUTEX(quirk_flags_mutex);
+
+static int param_set_quirkp(const char *val,
+			    const struct kernel_param *kp)
+{
+	guard(mutex)(&quirk_flags_mutex);
+	return param_set_charp(val, kp);
+}
+
+static const struct kernel_param_ops param_ops_quirkp = {
+	.set = param_set_quirkp,
+	.get = param_get_charp,
+	.free = param_free_charp,
+};
+
+#define param_check_quirkp param_check_charp
+
+module_param_array(quirk_flags, quirkp, NULL, 0644);
+MODULE_PARM_DESC(quirk_flags, "Add/modify USB audio quirks");
+
+/*
+ * we keep the snd_usb_audio_t instances by ourselves for merging
+ * the all interfaces on the same card as one sound device.
+ */
+
+static DEFINE_MUTEX(register_mutex);
+static struct snd_usb_audio *usb_chip[SNDRV_CARDS];
+static struct usb_driver usb_audio_driver;
+static struct snd_usb_platform_ops *platform_ops;
+
+/*
+ * Register platform specific operations that will be notified on events
+ * which occur in USB SND.  The platform driver can utilize this path to
+ * enable features, such as USB audio offloading, which allows for audio data
+ * to be queued by an audio DSP.
+ *
+ * Only one set of platform operations can be registered to USB SND.  The
+ * platform register operation is protected by the register_mutex.
+ */
+int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops)
+{
+	guard(mutex)(&register_mutex);
+	if (platform_ops)
+		return -EEXIST;
+
+	platform_ops = ops;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_usb_register_platform_ops);
+
+/*
+ * Unregisters the current set of platform operations.  This allows for
+ * a new set to be registered if required.
+ *
+ * The platform unregister operation is protected by the register_mutex.
+ */
+int snd_usb_unregister_platform_ops(void)
+{
+	guard(mutex)(&register_mutex);
+	platform_ops = NULL;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_usb_unregister_platform_ops);
+
+/*
+ * in case the platform driver was not ready at the time of USB SND
+ * device connect, expose an API to discover all connected USB devices
+ * so it can populate any dependent resources/structures.
+ */
+void snd_usb_rediscover_devices(void)
+{
+	int i;
+
+	guard(mutex)(&register_mutex);
+
+	if (!platform_ops || !platform_ops->connect_cb)
+		return;
+
+	for (i = 0; i < SNDRV_CARDS; i++) {
+		if (usb_chip[i])
+			platform_ops->connect_cb(usb_chip[i]);
+	}
+}
+EXPORT_SYMBOL_GPL(snd_usb_rediscover_devices);
+
+/*
+ * Checks to see if requested audio profile, i.e sample rate, # of
+ * channels, etc... is supported by the substream associated to the
+ * USB audio device.
+ */
+struct snd_usb_stream *
+snd_usb_find_suppported_substream(int card_idx, struct snd_pcm_hw_params *params,
+				  int direction)
+{
+	struct snd_usb_audio *chip;
+	struct snd_usb_substream *subs;
+	struct snd_usb_stream *as;
+
+	/*
+	 * Register mutex is held when populating and clearing usb_chip
+	 * array.
+	 */
+	guard(mutex)(&register_mutex);
+	chip = usb_chip[card_idx];
+
+	if (chip && enable[card_idx]) {
+		list_for_each_entry(as, &chip->pcm_list, list) {
+			subs = &as->substream[direction];
+			if (snd_usb_find_substream_format(subs, params))
+				return as;
+		}
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(snd_usb_find_suppported_substream);
+
+/*
+ * disconnect streams
+ * called from usb_audio_disconnect()
+ */
+static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
+{
+	int idx;
+	struct snd_usb_substream *subs;
+
+	for (idx = 0; idx < 2; idx++) {
+		subs = &as->substream[idx];
+		if (!subs->num_formats)
+			continue;
+		subs->data_endpoint = NULL;
+		subs->sync_endpoint = NULL;
+	}
+}
+
+static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface)
+{
+	struct usb_device *dev = chip->dev;
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct usb_interface *iface = usb_ifnum_to_if(dev, interface);
+
+	if (!iface) {
+		dev_err(&dev->dev, "%u:%d : does not exist\n",
+			ctrlif, interface);
+		return -EINVAL;
+	}
+
+	alts = &iface->altsetting[0];
+	altsd = get_iface_desc(alts);
+
+	/*
+	 * Android with both accessory and audio interfaces enabled gets the
+	 * interface numbers wrong.
+	 */
+	if ((chip->usb_id == USB_ID(0x18d1, 0x2d04) ||
+	     chip->usb_id == USB_ID(0x18d1, 0x2d05)) &&
+	    interface == 0 &&
+	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
+	    altsd->bInterfaceSubClass == USB_SUBCLASS_VENDOR_SPEC) {
+		interface = 2;
+		iface = usb_ifnum_to_if(dev, interface);
+		if (!iface)
+			return -EINVAL;
+		alts = &iface->altsetting[0];
+		altsd = get_iface_desc(alts);
+	}
+
+	if (usb_interface_claimed(iface)) {
+		dev_dbg(&dev->dev, "%d:%d: skipping, already claimed\n",
+			ctrlif, interface);
+		return -EINVAL;
+	}
+
+	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
+	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
+	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {
+		int err = snd_usb_midi_v2_create(chip, iface, NULL,
+						 chip->usb_id);
+		if (err < 0) {
+			dev_err(&dev->dev,
+				"%u:%d: cannot create sequencer device\n",
+				ctrlif, interface);
+			return -EINVAL;
+		}
+		return usb_driver_claim_interface(&usb_audio_driver, iface,
+						  USB_AUDIO_IFACE_UNUSED);
+	}
+
+	if ((altsd->bInterfaceClass != USB_CLASS_AUDIO &&
+	     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
+	    altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING) {
+		dev_dbg(&dev->dev,
+			"%u:%d: skipping non-supported interface %d\n",
+			ctrlif, interface, altsd->bInterfaceClass);
+		/* skip non-supported classes */
+		return -EINVAL;
+	}
+
+	if (snd_usb_get_speed(dev) == USB_SPEED_LOW) {
+		dev_err(&dev->dev, "low speed audio streaming not supported\n");
+		return -EINVAL;
+	}
+
+	snd_usb_add_ctrl_interface_link(chip, interface, ctrlif);
+
+	if (! snd_usb_parse_audio_interface(chip, interface)) {
+		usb_set_interface(dev, interface, 0); /* reset the current interface */
+		return usb_driver_claim_interface(&usb_audio_driver, iface,
+						  USB_AUDIO_IFACE_UNUSED);
+	}
+
+	return 0;
+}
+
+/*
+ * parse audio control descriptor and create pcm/midi streams
+ */
+static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
+{
+	struct usb_device *dev = chip->dev;
+	struct usb_host_interface *host_iface;
+	struct usb_interface_descriptor *altsd;
+	int i, protocol;
+
+	/* find audiocontrol interface */
+	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
+	altsd = get_iface_desc(host_iface);
+	protocol = altsd->bInterfaceProtocol;
+
+	switch (protocol) {
+	default:
+		dev_warn(&dev->dev,
+			 "unknown interface protocol %#02x, assuming v1\n",
+			 protocol);
+		fallthrough;
+
+	case UAC_VERSION_1: {
+		struct uac1_ac_header_descriptor *h1;
+		int rest_bytes;
+
+		h1 = snd_usb_find_csint_desc(host_iface->extra,
+							 host_iface->extralen,
+							 NULL, UAC_HEADER);
+		if (!h1 || h1->bLength < sizeof(*h1)) {
+			dev_err(&dev->dev, "cannot find UAC_HEADER\n");
+			return -EINVAL;
+		}
+
+		rest_bytes = (void *)(host_iface->extra +
+				host_iface->extralen) - (void *)h1;
+
+		/* just to be sure -- this shouldn't hit at all */
+		if (rest_bytes <= 0) {
+			dev_err(&dev->dev, "invalid control header\n");
+			return -EINVAL;
+		}
+
+		if (rest_bytes < sizeof(*h1)) {
+			dev_err(&dev->dev, "too short v1 buffer descriptor\n");
+			return -EINVAL;
+		}
+
+		if (!h1->bInCollection) {
+			dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
+			return -EINVAL;
+		}
+
+		if (rest_bytes < h1->bLength) {
+			dev_err(&dev->dev, "invalid buffer length (v1)\n");
+			return -EINVAL;
+		}
+
+		if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
+			dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
+			return -EINVAL;
+		}
+
+		for (i = 0; i < h1->bInCollection; i++)
+			snd_usb_create_stream(chip, ctrlif, h1->baInterfaceNr[i]);
+
+		break;
+	}
+
+	case UAC_VERSION_2:
+	case UAC_VERSION_3: {
+		struct usb_interface_assoc_descriptor *assoc =
+			usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
+
+		if (!assoc) {
+			/*
+			 * Firmware writers cannot count to three.  So to find
+			 * the IAD on the NuForce UDH-100, also check the next
+			 * interface.
+			 */
+			struct usb_interface *iface =
+				usb_ifnum_to_if(dev, ctrlif + 1);
+			if (iface &&
+			    iface->intf_assoc &&
+			    iface->intf_assoc->bFunctionClass == USB_CLASS_AUDIO &&
+			    iface->intf_assoc->bFunctionProtocol == UAC_VERSION_2)
+				assoc = iface->intf_assoc;
+		}
+
+		if (!assoc) {
+			dev_err(&dev->dev, "Audio class v2/v3 interfaces need an interface association\n");
+			return -EINVAL;
+		}
+
+		if (protocol == UAC_VERSION_3) {
+			int badd = assoc->bFunctionSubClass;
+
+			if (badd != UAC3_FUNCTION_SUBCLASS_FULL_ADC_3_0 &&
+			    (badd < UAC3_FUNCTION_SUBCLASS_GENERIC_IO ||
+			     badd > UAC3_FUNCTION_SUBCLASS_SPEAKERPHONE)) {
+				dev_err(&dev->dev,
+					"Unsupported UAC3 BADD profile\n");
+				return -EINVAL;
+			}
+
+			chip->badd_profile = badd;
+		}
+
+		for (i = 0; i < assoc->bInterfaceCount; i++) {
+			int intf = assoc->bFirstInterface + i;
+
+			if (intf != ctrlif)
+				snd_usb_create_stream(chip, ctrlif, intf);
+		}
+
+		break;
+	}
+	}
+
+	return 0;
+}
+
+/*
+ * Profile name preset table
+ */
+struct usb_audio_device_name {
+	u32 id;
+	const char *vendor_name;
+	const char *product_name;
+	const char *profile_name;	/* override card->longname */
+};
+
+#define PROFILE_NAME(vid, pid, vendor, product, profile)	 \
+	{ .id = USB_ID(vid, pid), .vendor_name = (vendor),	 \
+	  .product_name = (product), .profile_name = (profile) }
+#define DEVICE_NAME(vid, pid, vendor, product) \
+	PROFILE_NAME(vid, pid, vendor, product, NULL)
+
+/* vendor/product and profile name presets, sorted in device id order */
+static const struct usb_audio_device_name usb_audio_names[] = {
+	/* HP Thunderbolt Dock Audio Headset */
+	PROFILE_NAME(0x03f0, 0x0269, "HP", "Thunderbolt Dock Audio Headset",
+		     "HP-Thunderbolt-Dock-Audio-Headset"),
+	/* HP Thunderbolt Dock Audio Module */
+	PROFILE_NAME(0x03f0, 0x0567, "HP", "Thunderbolt Dock Audio Module",
+		     "HP-Thunderbolt-Dock-Audio-Module"),
+
+	/* Two entries for Gigabyte TRX40 Aorus Master:
+	 * TRX40 Aorus Master has two USB-audio devices, one for the front
+	 * headphone with ESS SABRE9218 DAC chip, while another for the rest
+	 * I/O (the rear panel and the front mic) with Realtek ALC1220-VB.
+	 * Here we provide two distinct names for making UCM profiles easier.
+	 */
+	PROFILE_NAME(0x0414, 0xa000, "Gigabyte", "Aorus Master Front Headphone",
+		     "Gigabyte-Aorus-Master-Front-Headphone"),
+	PROFILE_NAME(0x0414, 0xa001, "Gigabyte", "Aorus Master Main Audio",
+		     "Gigabyte-Aorus-Master-Main-Audio"),
+
+	/* Gigabyte TRX40 Aorus Pro WiFi */
+	PROFILE_NAME(0x0414, 0xa002,
+		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
+
+	/* Creative/E-Mu devices */
+	DEVICE_NAME(0x041e, 0x3010, "Creative Labs", "Sound Blaster MP3+"),
+	/* Creative/Toshiba Multimedia Center SB-0500 */
+	DEVICE_NAME(0x041e, 0x3048, "Toshiba", "SB-0500"),
+
+	/* Logitech Audio Devices */
+	DEVICE_NAME(0x046d, 0x0867, "Logitech, Inc.", "Logi-MeetUp"),
+	DEVICE_NAME(0x046d, 0x0874, "Logitech, Inc.", "Logi-Tap-Audio"),
+	DEVICE_NAME(0x046d, 0x087c, "Logitech, Inc.", "Logi-Huddle"),
+	DEVICE_NAME(0x046d, 0x0898, "Logitech, Inc.", "Logi-RB-Audio"),
+	DEVICE_NAME(0x046d, 0x08d2, "Logitech, Inc.", "Logi-RBM-Audio"),
+	DEVICE_NAME(0x046d, 0x0990, "Logitech, Inc.", "QuickCam Pro 9000"),
+
+	DEVICE_NAME(0x05e1, 0x0408, "Syntek", "STK1160"),
+	DEVICE_NAME(0x05e1, 0x0480, "Hauppauge", "Woodbury"),
+
+	/* ASUS ROG Zenith II: this machine has also two devices, one for
+	 * the front headphone and another for the rest
+	 */
+	PROFILE_NAME(0x0b05, 0x1915, "ASUS", "Zenith II Front Headphone",
+		     "Zenith-II-Front-Headphone"),
+	PROFILE_NAME(0x0b05, 0x1916, "ASUS", "Zenith II Main Audio",
+		     "Zenith-II-Main-Audio"),
+
+	/* ASUS ROG Strix */
+	PROFILE_NAME(0x0b05, 0x1917,
+		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
+	/* ASUS PRIME TRX40 PRO-S */
+	PROFILE_NAME(0x0b05, 0x1918,
+		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
+
+	/* Dell WD15 Dock */
+	PROFILE_NAME(0x0bda, 0x4014, "Dell", "WD15 Dock", "Dell-WD15-Dock"),
+	/* Dell WD19 Dock */
+	PROFILE_NAME(0x0bda, 0x402e, "Dell", "WD19 Dock", "Dell-WD15-Dock"),
+
+	DEVICE_NAME(0x0ccd, 0x0028, "TerraTec", "Aureon5.1MkII"),
+
+	/*
+	 * The original product_name is "USB Sound Device", however this name
+	 * is also used by the CM106 based cards, so make it unique.
+	 */
+	DEVICE_NAME(0x0d8c, 0x0102, NULL, "ICUSBAUDIO7D"),
+	DEVICE_NAME(0x0d8c, 0x0103, NULL, "Audio Advantage MicroII"),
+
+	/* MSI TRX40 Creator */
+	PROFILE_NAME(0x0db0, 0x0d64,
+		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
+	/* MSI TRX40 */
+	PROFILE_NAME(0x0db0, 0x543d,
+		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
+
+	DEVICE_NAME(0x0fd9, 0x0008, "Hauppauge", "HVR-950Q"),
+
+	/* Dock/Stand for HP Engage Go */
+	PROFILE_NAME(0x103c, 0x830a, "HP", "HP Engage Go Dock",
+		     "HP-Engage-Go-Dock"),
+
+	/* Stanton/N2IT Final Scratch v1 device ('Scratchamp') */
+	DEVICE_NAME(0x103d, 0x0100, "Stanton", "ScratchAmp"),
+	DEVICE_NAME(0x103d, 0x0101, "Stanton", "ScratchAmp"),
+
+	/* aka. Serato Scratch Live DJ Box */
+	DEVICE_NAME(0x13e5, 0x0001, "Rane", "SL-1"),
+
+	/* Lenovo ThinkStation P620 Rear Line-in, Line-out and Microphone */
+	PROFILE_NAME(0x17aa, 0x1046, "Lenovo", "ThinkStation P620 Rear",
+		     "Lenovo-ThinkStation-P620-Rear"),
+	/* Lenovo ThinkStation P620 Internal Speaker + Front Headset */
+	PROFILE_NAME(0x17aa, 0x104d, "Lenovo", "ThinkStation P620 Main",
+		     "Lenovo-ThinkStation-P620-Main"),
+
+	/* Asrock TRX40 Creator */
+	PROFILE_NAME(0x26ce, 0x0a01,
+		     "Realtek", "ALC1220-VB-DT", "Realtek-ALC1220-VB-Desktop"),
+
+	DEVICE_NAME(0x2040, 0x7200, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x7201, "Hauppauge", "HVR-950Q-MXL"),
+	DEVICE_NAME(0x2040, 0x7210, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x7211, "Hauppauge", "HVR-950Q-MXL"),
+	DEVICE_NAME(0x2040, 0x7213, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x7217, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x721b, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x721e, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x721f, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x7240, "Hauppauge", "HVR-850"),
+	DEVICE_NAME(0x2040, 0x7260, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x7270, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x7280, "Hauppauge", "HVR-950Q"),
+	DEVICE_NAME(0x2040, 0x7281, "Hauppauge", "HVR-950Q-MXL"),
+	DEVICE_NAME(0x2040, 0x8200, "Hauppauge", "Woodbury"),
+
+	{ } /* terminator */
+};
+
+static const struct usb_audio_device_name *
+lookup_device_name(u32 id)
+{
+	static const struct usb_audio_device_name *p;
+
+	for (p = usb_audio_names; p->id; p++)
+		if (p->id == id)
+			return p;
+	return NULL;
+}
+
+/*
+ * free the chip instance
+ *
+ * here we have to do not much, since pcm and controls are already freed
+ *
+ */
+
+static void snd_usb_audio_free(struct snd_card *card)
+{
+	struct snd_usb_audio *chip = card->private_data;
+
+	snd_usb_endpoint_free_all(chip);
+	snd_usb_midi_v2_free_all(chip);
+
+	mutex_destroy(&chip->mutex);
+	if (!atomic_read(&chip->shutdown))
+		dev_set_drvdata(&chip->dev->dev, NULL);
+}
+
+static void usb_audio_make_shortname(struct usb_device *dev,
+				     struct snd_usb_audio *chip,
+				     const struct snd_usb_audio_quirk *quirk)
+{
+	struct snd_card *card = chip->card;
+	const struct usb_audio_device_name *preset;
+	const char *s = NULL;
+
+	preset = lookup_device_name(chip->usb_id);
+	if (preset && preset->product_name)
+		s = preset->product_name;
+	else if (quirk && quirk->product_name)
+		s = quirk->product_name;
+	if (s && *s) {
+		strscpy(card->shortname, s, sizeof(card->shortname));
+		return;
+	}
+
+	/* retrieve the device string as shortname */
+	if (dev->product && *dev->product) {
+		strscpy(card->shortname, dev->product);
+	} else {
+		/* no name available from anywhere, so use ID */
+		scnprintf(card->shortname, sizeof(card->shortname),
+			  "USB Device %#04x:%#04x",
+			  USB_ID_VENDOR(chip->usb_id),
+			  USB_ID_PRODUCT(chip->usb_id));
+	}
+
+	strim(card->shortname);
+}
+
+static void usb_audio_make_longname(struct usb_device *dev,
+				    struct snd_usb_audio *chip,
+				    const struct snd_usb_audio_quirk *quirk)
+{
+	struct snd_card *card = chip->card;
+	const struct usb_audio_device_name *preset;
+	const char *s = NULL;
+	int len;
+
+	preset = lookup_device_name(chip->usb_id);
+
+	/* shortcut - if any pre-defined string is given, use it */
+	if (preset && preset->profile_name)
+		s = preset->profile_name;
+	if (s && *s) {
+		strscpy(card->longname, s, sizeof(card->longname));
+		return;
+	}
+
+	if (preset && preset->vendor_name)
+		s = preset->vendor_name;
+	else if (quirk && quirk->vendor_name)
+		s = quirk->vendor_name;
+	*card->longname = 0;
+	if (s && *s)
+		strscpy(card->longname, s);
+	else if (dev->manufacturer && *dev->manufacturer)
+		strscpy(card->longname, dev->manufacturer);
+
+	if (*card->longname) {
+		strim(card->longname);
+		if (*card->longname)
+			strlcat(card->longname, " ", sizeof(card->longname));
+	}
+
+	strlcat(card->longname, card->shortname, sizeof(card->longname));
+
+	len = strlcat(card->longname, " at ", sizeof(card->longname));
+
+	if (len < sizeof(card->longname))
+		usb_make_path(dev, card->longname + len, sizeof(card->longname) - len);
+
+	switch (snd_usb_get_speed(dev)) {
+	case USB_SPEED_LOW:
+		strlcat(card->longname, ", low speed", sizeof(card->longname));
+		break;
+	case USB_SPEED_FULL:
+		strlcat(card->longname, ", full speed", sizeof(card->longname));
+		break;
+	case USB_SPEED_HIGH:
+		strlcat(card->longname, ", high speed", sizeof(card->longname));
+		break;
+	case USB_SPEED_SUPER:
+		strlcat(card->longname, ", super speed", sizeof(card->longname));
+		break;
+	case USB_SPEED_SUPER_PLUS:
+		strlcat(card->longname, ", super speed plus", sizeof(card->longname));
+		break;
+	default:
+		break;
+	}
+}
+
+static void snd_usb_init_quirk_flags(int idx, struct snd_usb_audio *chip)
+{
+	size_t i;
+
+	guard(mutex)(&quirk_flags_mutex);
+
+	/* old style option found: the position-based integer value */
+	if (quirk_flags[idx] &&
+	    !kstrtou64(quirk_flags[idx], 0, &chip->quirk_flags)) {
+		snd_usb_apply_flag_dbg("module param", chip, chip->quirk_flags);
+		return;
+	}
+
+	/* take the default quirk from the quirk table */
+	snd_usb_init_quirk_flags_table(chip);
+
+	/* add or correct quirk bits from options */
+	for (i = 0; i < ARRAY_SIZE(quirk_flags); i++) {
+		if (!quirk_flags[i] || !*quirk_flags[i])
+			break;
+
+		snd_usb_init_quirk_flags_parse_string(chip, quirk_flags[i]);
+	}
+}
+
+/*
+ * create a chip instance and set its names.
+ */
+static int snd_usb_audio_create(struct usb_interface *intf,
+				struct usb_device *dev, int idx,
+				const struct snd_usb_audio_quirk *quirk,
+				unsigned int usb_id,
+				struct snd_usb_audio **rchip)
+{
+	struct snd_card *card;
+	struct snd_usb_audio *chip;
+	int err;
+	char component[14];
+
+	*rchip = NULL;
+
+	switch (snd_usb_get_speed(dev)) {
+	case USB_SPEED_LOW:
+	case USB_SPEED_FULL:
+	case USB_SPEED_HIGH:
+	case USB_SPEED_SUPER:
+	case USB_SPEED_SUPER_PLUS:
+		break;
+	default:
+		dev_err(&dev->dev, "unknown device speed %d\n", snd_usb_get_speed(dev));
+		return -ENXIO;
+	}
+
+	err = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
+			   sizeof(*chip), &card);
+	if (err < 0) {
+		dev_err(&dev->dev, "cannot create card instance %d\n", idx);
+		return err;
+	}
+
+	chip = card->private_data;
+	mutex_init(&chip->mutex);
+	chip->index = idx;
+	chip->dev = dev;
+	chip->card = card;
+	chip->setup = device_setup[idx];
+	chip->generic_implicit_fb = implicit_fb[idx];
+	chip->autoclock = autoclock;
+	chip->lowlatency = lowlatency;
+	atomic_set(&chip->active, 1); /* avoid autopm during probing */
+	snd_refcount_init(&chip->usage_count);
+	atomic_set(&chip->shutdown, 0);
+
+	chip->usb_id = usb_id;
+	INIT_LIST_HEAD(&chip->pcm_list);
+	INIT_LIST_HEAD(&chip->ep_list);
+	INIT_LIST_HEAD(&chip->iface_ref_list);
+	INIT_LIST_HEAD(&chip->clock_ref_list);
+	INIT_LIST_HEAD(&chip->midi_list);
+	INIT_LIST_HEAD(&chip->midi_v2_list);
+	INIT_LIST_HEAD(&chip->mixer_list);
+
+	snd_usb_init_quirk_flags(idx, chip);
+
+	card->private_free = snd_usb_audio_free;
+
+	strscpy(card->driver, "USB-Audio");
+	scnprintf(component, sizeof(component), "USB%04x:%04x",
+		  USB_ID_VENDOR(chip->usb_id), USB_ID_PRODUCT(chip->usb_id));
+	snd_component_add(card, component);
+
+	usb_audio_make_shortname(dev, chip, quirk);
+	usb_audio_make_longname(dev, chip, quirk);
+
+	snd_usb_audio_create_proc(chip);
+
+	*rchip = chip;
+	return 0;
+}
+
+/* look for a matching quirk alias id */
+static bool get_alias_id(struct usb_device *dev, unsigned int *id)
+{
+	int i;
+	unsigned int src, dst;
+
+	for (i = 0; i < ARRAY_SIZE(quirk_alias); i++) {
+		if (!quirk_alias[i] ||
+		    sscanf(quirk_alias[i], "%x:%x", &src, &dst) != 2 ||
+		    src != *id)
+			continue;
+		dev_info(&dev->dev,
+			 "device (%04x:%04x): applying quirk alias %04x:%04x\n",
+			 USB_ID_VENDOR(*id), USB_ID_PRODUCT(*id),
+			 USB_ID_VENDOR(dst), USB_ID_PRODUCT(dst));
+		*id = dst;
+		return true;
+	}
+
+	return false;
+}
+
+static int check_delayed_register_option(struct snd_usb_audio *chip)
+{
+	int i;
+	unsigned int id, inum;
+
+	for (i = 0; i < ARRAY_SIZE(delayed_register); i++) {
+		if (delayed_register[i] &&
+		    sscanf(delayed_register[i], "%x:%x", &id, &inum) == 2 &&
+		    id == chip->usb_id)
+			return inum;
+	}
+
+	return -1;
+}
+
+static const struct usb_device_id usb_audio_ids[]; /* defined below */
+
+/* look for the last interface that matches with our ids and remember it */
+static void find_last_interface(struct snd_usb_audio *chip)
+{
+	struct usb_host_config *config = chip->dev->actconfig;
+	struct usb_interface *intf;
+	int i;
+
+	if (!config)
+		return;
+	for (i = 0; i < config->desc.bNumInterfaces; i++) {
+		intf = config->interface[i];
+		if (usb_match_id(intf, usb_audio_ids))
+			chip->last_iface = intf->altsetting[0].desc.bInterfaceNumber;
+	}
+	usb_audio_dbg(chip, "Found last interface = %d\n", chip->last_iface);
+}
+
+/* look for the corresponding quirk */
+static const struct snd_usb_audio_quirk *
+get_alias_quirk(struct usb_interface *intf, unsigned int id)
+{
+	const struct usb_device_id *p;
+	struct usb_device_id match_id;
+
+	for (p = usb_audio_ids; p->match_flags; p++) {
+		if ((p->match_flags & USB_DEVICE_ID_MATCH_DEVICE) !=
+		     USB_DEVICE_ID_MATCH_DEVICE)
+			continue;
+		if (p->idVendor != USB_ID_VENDOR(id) ||
+		    p->idProduct != USB_ID_PRODUCT(id))
+			continue;
+
+		match_id = *p;
+		match_id.match_flags &= ~USB_DEVICE_ID_MATCH_DEVICE;
+		if (!match_id.match_flags || usb_match_one_id(intf, &match_id))
+			return (const struct snd_usb_audio_quirk *)
+				p->driver_info;
+	}
+	return NULL;
+}
+
+/* register card if we reach to the last interface or to the specified
+ * one given via option
+ */
+static int try_to_register_card(struct snd_usb_audio *chip, int ifnum)
+{
+	struct usb_interface *iface;
+
+	if (check_delayed_register_option(chip) == ifnum ||
+	    chip->last_iface == ifnum)
+		return snd_card_register(chip->card);
+
+	iface = usb_ifnum_to_if(chip->dev, chip->last_iface);
+	if (iface && usb_interface_claimed(iface))
+		return snd_card_register(chip->card);
+
+	return 0;
+}
+
+static void usb_audio_disconnect_components(struct snd_usb_audio *chip)
+{
+	struct snd_usb_stream *as;
+	struct snd_usb_endpoint *ep;
+	struct usb_mixer_interface *mixer;
+	struct list_head *p;
+
+	/* release the pcm resources */
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		snd_usb_stream_disconnect(as);
+	}
+	/* release the endpoint resources */
+	list_for_each_entry(ep, &chip->ep_list, list) {
+		snd_usb_endpoint_release(ep);
+	}
+	/* release the midi resources */
+	list_for_each(p, &chip->midi_list) {
+		snd_usbmidi_disconnect(p);
+	}
+	snd_usb_midi_v2_disconnect_all(chip);
+	/*
+	 * Nice to check quirk && quirk->shares_media_device and
+	 * then call the snd_media_device_delete(). Don't have
+	 * access to the quirk here. snd_media_device_delete()
+	 * accesses mixer_list
+	 */
+	snd_media_device_delete(chip);
+
+	/* release mixer resources */
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		snd_usb_mixer_disconnect(mixer);
+	}
+}
+
+/*
+ * probe the active usb device
+ *
+ * note that this can be called multiple times per a device, when it
+ * includes multiple audio control interfaces.
+ *
+ * thus we check the usb device pointer and creates the card instance
+ * only at the first time.  the successive calls of this function will
+ * append the pcm interface to the corresponding card.
+ */
+static int usb_audio_probe(struct usb_interface *intf,
+			   const struct usb_device_id *usb_id)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	const struct snd_usb_audio_quirk *quirk =
+		(const struct snd_usb_audio_quirk *)usb_id->driver_info;
+	struct snd_usb_audio *chip;
+	int i, err;
+	struct usb_host_interface *alts;
+	int ifnum;
+	u32 id;
+
+	alts = &intf->altsetting[0];
+	ifnum = get_iface_desc(alts)->bInterfaceNumber;
+	id = USB_ID(le16_to_cpu(dev->descriptor.idVendor),
+		    le16_to_cpu(dev->descriptor.idProduct));
+	if (get_alias_id(dev, &id))
+		quirk = get_alias_quirk(intf, id);
+	if (quirk && quirk->ifnum >= 0 && ifnum != quirk->ifnum)
+		return -ENXIO;
+	if (quirk && quirk->ifnum == QUIRK_NODEV_INTERFACE)
+		return -ENODEV;
+
+	err = snd_usb_apply_boot_quirk(dev, intf, quirk, id);
+	if (err < 0)
+		return err;
+
+	/*
+	 * found a config.  now register to ALSA
+	 */
+
+	/* check whether it's already registered */
+	chip = NULL;
+	guard(mutex)(&register_mutex);
+	for (i = 0; i < SNDRV_CARDS; i++) {
+		if (usb_chip[i] && usb_chip[i]->dev == dev) {
+			if (atomic_read(&usb_chip[i]->shutdown)) {
+				dev_err(&dev->dev, "USB device is in the shutdown state, cannot create a card instance\n");
+				err = -EIO;
+				goto __error;
+			}
+			chip = usb_chip[i];
+			atomic_inc(&chip->active); /* avoid autopm */
+			break;
+		}
+	}
+	if (! chip) {
+		err = snd_usb_apply_boot_quirk_once(dev, intf, quirk, id);
+		if (err < 0)
+			goto __error;
+
+		/* it's a fresh one.
+		 * now look for an empty slot and create a new card instance
+		 */
+		for (i = 0; i < SNDRV_CARDS; i++)
+			if (!usb_chip[i] &&
+			    (vid[i] == -1 || vid[i] == USB_ID_VENDOR(id)) &&
+			    (pid[i] == -1 || pid[i] == USB_ID_PRODUCT(id))) {
+				if (enable[i]) {
+					err = snd_usb_audio_create(intf, dev, i, quirk,
+								   id, &chip);
+					if (err < 0)
+						goto __error;
+					break;
+				} else if (vid[i] != -1 || pid[i] != -1) {
+					dev_info(&dev->dev,
+						 "device (%04x:%04x) is disabled\n",
+						 USB_ID_VENDOR(id),
+						 USB_ID_PRODUCT(id));
+					err = -ENOENT;
+					goto __error;
+				}
+			}
+		if (!chip) {
+			dev_err(&dev->dev, "no available usb audio device\n");
+			err = -ENODEV;
+			goto __error;
+		}
+		find_last_interface(chip);
+	}
+
+	if (chip->num_interfaces >= MAX_CARD_INTERFACES) {
+		dev_info(&dev->dev, "Too many interfaces assigned to the single USB-audio card\n");
+		err = -EINVAL;
+		goto __error;
+	}
+
+	dev_set_drvdata(&dev->dev, chip);
+
+	if (ignore_ctl_error)
+		chip->quirk_flags |= QUIRK_FLAG_IGNORE_CTL_ERROR;
+
+	if (chip->quirk_flags & QUIRK_FLAG_DISABLE_AUTOSUSPEND)
+		usb_disable_autosuspend(interface_to_usbdev(intf));
+
+	/*
+	 * For devices with more than one control interface, we assume the
+	 * first contains the audio controls. We might need a more specific
+	 * check here in the future.
+	 */
+	if (!chip->ctrl_intf)
+		chip->ctrl_intf = alts;
+
+	err = 1; /* continue */
+	if (quirk && quirk->ifnum != QUIRK_NO_INTERFACE) {
+		/* need some special handlings */
+		err = snd_usb_create_quirk(chip, intf, &usb_audio_driver, quirk);
+		if (err < 0)
+			goto __error;
+	}
+
+	if (err > 0) {
+		/* create normal USB audio interfaces */
+		err = snd_usb_create_streams(chip, ifnum);
+		if (err < 0)
+			goto __error;
+		err = snd_usb_create_mixer(chip, ifnum);
+		if (err < 0)
+			goto __error;
+	}
+
+	if (chip->need_delayed_register) {
+		dev_info(&dev->dev,
+			 "Found post-registration device assignment: %08x:%02x\n",
+			 chip->usb_id, ifnum);
+		chip->need_delayed_register = false; /* clear again */
+	}
+
+	err = try_to_register_card(chip, ifnum);
+	if (err < 0)
+		goto __error_no_register;
+
+	if (chip->quirk_flags & QUIRK_FLAG_SHARE_MEDIA_DEVICE) {
+		/* don't want to fail when snd_media_device_create() fails */
+		snd_media_device_create(chip, intf);
+	}
+
+	if (quirk)
+		chip->quirk_type = quirk->type;
+
+	usb_chip[chip->index] = chip;
+	chip->intf[chip->num_interfaces] = intf;
+	chip->num_interfaces++;
+	usb_set_intfdata(intf, chip);
+	atomic_dec(&chip->active);
+
+	if (platform_ops && platform_ops->connect_cb)
+		platform_ops->connect_cb(chip);
+
+	return 0;
+
+ __error:
+	/* in the case of error in secondary interface, still try to register */
+	if (chip)
+		try_to_register_card(chip, ifnum);
+
+ __error_no_register:
+	if (chip) {
+		/* chip->active is inside the chip->card object,
+		 * decrement before memory is possibly returned.
+		 */
+		atomic_dec(&chip->active);
+		if (!chip->num_interfaces) {
+			usb_audio_disconnect_components(chip);
+			snd_card_free(chip->card);
+		}
+	}
+	return err;
+}
+
+/*
+ * we need to take care of counter, since disconnection can be called also
+ * many times as well as usb_audio_probe().
+ */
+static bool __usb_audio_disconnect(struct usb_interface *intf,
+				   struct snd_usb_audio *chip,
+				   struct snd_card *card)
+{
+	guard(mutex)(&register_mutex);
+
+	if (platform_ops && platform_ops->disconnect_cb)
+		platform_ops->disconnect_cb(chip);
+
+	if (atomic_inc_return(&chip->shutdown) == 1) {
+		/* wait until all pending tasks done;
+		 * they are protected by snd_usb_lock_shutdown()
+		 */
+		snd_refcount_sync(&chip->usage_count);
+		snd_card_disconnect(card);
+		usb_audio_disconnect_components(chip);
+	}
+
+	if (chip->quirk_flags & QUIRK_FLAG_DISABLE_AUTOSUSPEND)
+		usb_enable_autosuspend(interface_to_usbdev(intf));
+
+	chip->num_interfaces--;
+	if (chip->num_interfaces > 0)
+		return false;
+
+	usb_chip[chip->index] = NULL;
+	return true;
+}
+
+static void usb_audio_disconnect(struct usb_interface *intf)
+{
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
+	struct snd_card *card;
+
+	if (chip == USB_AUDIO_IFACE_UNUSED)
+		return;
+
+	card = chip->card;
+	if (__usb_audio_disconnect(intf, chip, card))
+		snd_card_free_when_closed(card);
+}
+
+/* lock the shutdown (disconnect) task and autoresume */
+int snd_usb_lock_shutdown(struct snd_usb_audio *chip)
+{
+	int err;
+
+	snd_refcount_get(&chip->usage_count);
+	if (atomic_read(&chip->shutdown)) {
+		err = -EIO;
+		goto error;
+	}
+	err = snd_usb_autoresume(chip);
+	if (err < 0)
+		goto error;
+	return 0;
+
+ error:
+	snd_refcount_put(&chip->usage_count);
+	return err;
+}
+EXPORT_SYMBOL_GPL(snd_usb_lock_shutdown);
+
+/* autosuspend and unlock the shutdown */
+void snd_usb_unlock_shutdown(struct snd_usb_audio *chip)
+{
+	snd_usb_autosuspend(chip);
+	snd_refcount_put(&chip->usage_count);
+}
+EXPORT_SYMBOL_GPL(snd_usb_unlock_shutdown);
+
+int snd_usb_autoresume(struct snd_usb_audio *chip)
+{
+	int i, err;
+
+	if (atomic_read(&chip->shutdown))
+		return -EIO;
+	if (atomic_inc_return(&chip->active) != 1)
+		return 0;
+
+	for (i = 0; i < chip->num_interfaces; i++) {
+		err = usb_autopm_get_interface(chip->intf[i]);
+		if (err < 0) {
+			/* rollback */
+			while (--i >= 0)
+				usb_autopm_put_interface(chip->intf[i]);
+			atomic_dec(&chip->active);
+			return err;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_usb_autoresume);
+
+void snd_usb_autosuspend(struct snd_usb_audio *chip)
+{
+	int i;
+
+	if (atomic_read(&chip->shutdown))
+		return;
+	if (!atomic_dec_and_test(&chip->active))
+		return;
+
+	for (i = 0; i < chip->num_interfaces; i++)
+		usb_autopm_put_interface(chip->intf[i]);
+}
+EXPORT_SYMBOL_GPL(snd_usb_autosuspend);
+
+static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
+	struct snd_usb_stream *as;
+	struct snd_usb_endpoint *ep;
+	struct usb_mixer_interface *mixer;
+	struct list_head *p;
+
+	if (chip == USB_AUDIO_IFACE_UNUSED)
+		return 0;
+
+	if (!chip->num_suspended_intf++) {
+		list_for_each_entry(as, &chip->pcm_list, list)
+			snd_usb_pcm_suspend(as);
+		list_for_each_entry(ep, &chip->ep_list, list)
+			snd_usb_endpoint_suspend(ep);
+		list_for_each(p, &chip->midi_list)
+			snd_usbmidi_suspend(p);
+		list_for_each_entry(mixer, &chip->mixer_list, list)
+			snd_usb_mixer_suspend(mixer);
+		snd_usb_midi_v2_suspend_all(chip);
+	}
+
+	if (!PMSG_IS_AUTO(message) && !chip->system_suspend) {
+		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
+		chip->system_suspend = chip->num_suspended_intf;
+	}
+
+	if (platform_ops && platform_ops->suspend_cb)
+		platform_ops->suspend_cb(intf, message);
+
+	return 0;
+}
+
+static int usb_audio_resume(struct usb_interface *intf)
+{
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
+	struct snd_usb_stream *as;
+	struct usb_mixer_interface *mixer;
+	struct list_head *p;
+	int err = 0;
+
+	if (chip == USB_AUDIO_IFACE_UNUSED)
+		return 0;
+
+	atomic_inc(&chip->active); /* avoid autopm */
+	if (chip->num_suspended_intf > 1)
+		goto out;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		err = snd_usb_pcm_resume(as);
+		if (err < 0) {
+			if (!chip->system_suspend)
+				goto err_out;
+			goto out;
+		}
+	}
+
+	/*
+	 * ALSA leaves material resumption to user space
+	 * we just notify and restart the mixers
+	 */
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		err = snd_usb_mixer_resume(mixer);
+		if (err < 0) {
+			if (!chip->system_suspend)
+				goto err_out;
+			goto out;
+		}
+	}
+
+	list_for_each(p, &chip->midi_list) {
+		snd_usbmidi_resume(p);
+	}
+
+	snd_usb_midi_v2_resume_all(chip);
+
+	if (platform_ops && platform_ops->resume_cb)
+		platform_ops->resume_cb(intf);
+
+ out:
+	if (chip->num_suspended_intf == chip->system_suspend) {
+		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
+		chip->system_suspend = 0;
+	}
+	chip->num_suspended_intf--;
+
+err_out:
+	atomic_dec(&chip->active); /* allow autopm after this point */
+	return err;
+}
+
+static const struct usb_device_id usb_audio_ids [] = {
+#include "quirks-table.h"
+    { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
+      .bInterfaceClass = USB_CLASS_AUDIO,
+      .bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL },
+    { }						/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, usb_audio_ids);
+
+/*
+ * entry point for linux usb interface
+ */
+
+static struct usb_driver usb_audio_driver = {
+	.name =		"snd-usb-audio",
+	.probe =	usb_audio_probe,
+	.disconnect =	usb_audio_disconnect,
+	.suspend =	usb_audio_suspend,
+	.resume =	usb_audio_resume,
+	.reset_resume =	usb_audio_resume,
+	.id_table =	usb_audio_ids,
+	.supports_autosuspend = 1,
+};
+
+module_usb_driver(usb_audio_driver);
diff --git a/sound/usb/card.h b/sound/usb/card.h
new file mode 100644
index 000000000..8299ac241
--- /dev/null
+++ b/sound/usb/card.h
@@ -0,0 +1,228 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_CARD_H
+#define __USBAUDIO_CARD_H
+
+#define MAX_NR_RATES	1024
+#define MAX_PACKS	6		/* per URB */
+#define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
+#define MAX_URBS	12
+#define SYNC_URBS	4	/* always four urbs for sync */
+#define MAX_QUEUE	18	/* try not to exceed this queue length, in ms */
+
+struct audioformat {
+	struct list_head list;
+	u64 formats;			/* ALSA format bits */
+	unsigned int channels;		/* # channels */
+	unsigned int fmt_type;		/* USB audio format type (1-3) */
+	unsigned int fmt_bits;		/* number of significant bits */
+	unsigned int fmt_sz;		/* overall audio sub frame/slot size */
+	unsigned int frame_size;	/* samples per frame for non-audio */
+	unsigned char iface;		/* interface number */
+	unsigned char altsetting;	/* corresponding alternate setting */
+	unsigned char ep_idx;		/* endpoint array index */
+	unsigned char altset_idx;	/* array index of alternate setting */
+	unsigned char attributes;	/* corresponding attributes of cs endpoint */
+	unsigned char endpoint;		/* endpoint */
+	unsigned char ep_attr;		/* endpoint attributes */
+	bool implicit_fb;		/* implicit feedback endpoint */
+	unsigned char sync_ep;		/* sync endpoint number */
+	unsigned char sync_iface;	/* sync EP interface */
+	unsigned char sync_altsetting;	/* sync EP alternate setting */
+	unsigned char sync_ep_idx;	/* sync EP array index */
+	unsigned char datainterval;	/* log_2 of data packet interval */
+	unsigned char protocol;		/* UAC_VERSION_1/2/3 */
+	unsigned int maxpacksize;	/* max. packet size */
+	unsigned int rates;		/* rate bitmasks */
+	unsigned int rate_min, rate_max;	/* min/max rates */
+	unsigned int nr_rates;		/* number of rate table entries */
+	unsigned int *rate_table;	/* rate table */
+	unsigned char clock;		/* associated clock */
+	struct snd_pcm_chmap_elem *chmap; /* (optional) channel map */
+	bool dsd_dop;			/* add DOP headers in case of DSD samples */
+	bool dsd_bitrev;		/* reverse the bits of each DSD sample */
+	bool dsd_raw;			/* altsetting is raw DSD */
+};
+
+struct snd_usb_substream;
+struct snd_usb_iface_ref;
+struct snd_usb_clock_ref;
+struct snd_usb_endpoint;
+struct snd_usb_power_domain;
+
+struct snd_urb_ctx {
+	struct urb *urb;
+	unsigned int buffer_size;	/* size of data buffer, if data URB */
+	struct snd_usb_substream *subs;
+	struct snd_usb_endpoint *ep;
+	int index;	/* index for urb array */
+	int packets;	/* number of packets per urb */
+	int queued;	/* queued data bytes by this urb */
+	int packet_size[MAX_PACKS_HS]; /* size of packets for next submission */
+	struct list_head ready_list;
+};
+
+struct snd_usb_endpoint {
+	struct snd_usb_audio *chip;
+	struct snd_usb_iface_ref *iface_ref;
+	struct snd_usb_clock_ref *clock_ref;
+
+	int opened;		/* open refcount; protect with chip->mutex */
+	atomic_t running;	/* running status */
+	int ep_num;		/* the referenced endpoint number */
+	int type;		/* SND_USB_ENDPOINT_TYPE_* */
+
+	unsigned char iface;		/* interface number */
+	unsigned char altsetting;	/* corresponding alternate setting */
+	unsigned char ep_idx;		/* endpoint array index */
+
+	atomic_t state;		/* running state */
+
+	int (*prepare_data_urb) (struct snd_usb_substream *subs,
+				 struct urb *urb,
+				 bool in_stream_lock);
+	void (*retire_data_urb) (struct snd_usb_substream *subs,
+				 struct urb *urb);
+
+	struct snd_usb_substream *data_subs;
+	struct snd_usb_endpoint *sync_source;
+	struct snd_usb_endpoint *sync_sink;
+
+	struct snd_urb_ctx urb[MAX_URBS];
+
+	struct snd_usb_packet_info {
+		int packet_size[MAX_PACKS_HS];
+		int packets;
+	} next_packet[MAX_URBS];
+	unsigned int next_packet_head;	/* ring buffer offset to read */
+	unsigned int next_packet_queued; /* queued items in the ring buffer */
+	struct list_head ready_playback_urbs; /* playback URB FIFO for implicit fb */
+
+	unsigned int nurbs;		/* # urbs */
+	unsigned long active_mask;	/* bitmask of active urbs */
+	unsigned long unlink_mask;	/* bitmask of unlinked urbs */
+	atomic_t submitted_urbs;	/* currently submitted urbs */
+	char *syncbuf;			/* sync buffer for all sync URBs */
+	dma_addr_t sync_dma;		/* DMA address of syncbuf */
+
+	unsigned int pipe;		/* the data i/o pipe */
+	unsigned int packsize[2];	/* small/large packet sizes in samples */
+	unsigned int sample_rem;	/* remainder from division fs/pps */
+	unsigned int sample_accum;	/* sample accumulator */
+	unsigned int pps;		/* packets per second */
+	unsigned int freqn;		/* nominal sampling rate in fs/fps in Q16.16 format */
+	unsigned int freqm;		/* momentary sampling rate in fs/fps in Q16.16 format */
+	int	   freqshift;		/* how much to shift the feedback value to get Q16.16 */
+	unsigned int freqmax;		/* maximum sampling rate, used for buffer management */
+	unsigned int phase;		/* phase accumulator */
+	unsigned int maxpacksize;	/* max packet size in bytes */
+	unsigned int maxframesize;      /* max packet size in frames */
+	unsigned int max_urb_packs;	/* packets allocated per data URB */
+	unsigned int max_urb_frames;	/* max URB size in frames */
+	unsigned int curpacksize;	/* current packet size in bytes (for capture) */
+	unsigned int curframesize;      /* current packet size in frames (for capture) */
+	unsigned int syncmaxsize;	/* sync endpoint packet size */
+	unsigned int fill_max:1;	/* fill max packet size always */
+	unsigned int tenor_fb_quirk:1;	/* corrupted feedback data */
+	unsigned int datainterval;      /* log_2 of data packet interval */
+	unsigned int syncinterval;	/* P for adaptive mode, 0 otherwise */
+	unsigned char silence_value;
+	unsigned int stride;
+	int skip_packets;		/* quirks for devices to ignore the first n packets
+					   in a stream */
+	bool implicit_fb_sync;		/* syncs with implicit feedback */
+	bool lowlatency_playback;	/* low-latency playback mode */
+	bool need_setup;		/* (re-)need for hw_params? */
+	bool need_prepare;		/* (re-)need for prepare? */
+	bool fixed_rate;		/* skip rate setup */
+
+	/* for hw constraints */
+	const struct audioformat *cur_audiofmt;
+	unsigned int cur_rate;
+	snd_pcm_format_t cur_format;
+	unsigned int cur_channels;
+	unsigned int cur_frame_bytes;
+	unsigned int cur_period_frames;
+	unsigned int cur_period_bytes;
+	unsigned int cur_buffer_periods;
+
+	spinlock_t lock;
+	struct list_head list;
+};
+
+struct media_ctl;
+
+struct snd_usb_substream {
+	struct snd_usb_stream *stream;
+	struct usb_device *dev;
+	struct snd_pcm_substream *pcm_substream;
+	int direction;	/* playback or capture */
+	int endpoint;	/* assigned endpoint */
+	const struct audioformat *cur_audiofmt;	/* current audioformat pointer (for hw_params callback) */
+	struct snd_usb_power_domain *str_pd;	/* UAC3 Power Domain for streaming path */
+	unsigned int channels_max;	/* max channels in the all audiofmts */
+	unsigned int txfr_quirk:1;	/* allow sub-frame alignment */
+	unsigned int tx_length_quirk:1;	/* add length specifier to transfers */
+	unsigned int fmt_type;		/* USB audio format type (1-3) */
+	unsigned int pkt_offset_adj;	/* Bytes to drop from beginning of packets (for non-compliant devices) */
+	unsigned int stream_offset_adj;	/* Bytes to drop from beginning of stream (for non-compliant devices) */
+
+	unsigned int opened:1;		/* pcm device opened */
+	unsigned int running: 1;	/* running status */
+	unsigned int period_elapsed_pending;	/* delay period handling */
+
+	unsigned int buffer_bytes;	/* buffer size in bytes */
+	unsigned int inflight_bytes;	/* in-flight data bytes on buffer (for playback) */
+	unsigned int hwptr_done;	/* processed byte position in the buffer */
+	unsigned int transfer_done;	/* processed frames since last period update */
+	unsigned int frame_limit;	/* limits number of packets in URB */
+
+	/* data and sync endpoints for this stream */
+	unsigned int ep_num;		/* the endpoint number */
+	struct snd_usb_endpoint *data_endpoint;
+	struct snd_usb_endpoint *sync_endpoint;
+	unsigned long flags;
+	unsigned int speed;		/* USB_SPEED_XXX */
+
+	u64 formats;			/* format bitmasks (all or'ed) */
+	unsigned int num_formats;		/* number of supported audio formats (list) */
+	struct list_head fmt_list;	/* format list */
+	spinlock_t lock;
+
+	unsigned int last_frame_number;	/* stored frame number */
+
+	struct {
+		int marker;
+		int channel;
+		int byte_idx;
+	} dsd_dop;
+
+	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
+	bool lowlatency_playback;	/* low-latency playback mode */
+	struct media_ctl *media_ctl;
+};
+
+struct snd_usb_stream {
+	struct snd_usb_audio *chip;
+	struct snd_pcm *pcm;
+	int pcm_index;
+	unsigned int fmt_type;		/* USB audio format type (1-3) */
+	struct snd_usb_substream substream[2];
+	struct list_head list;
+};
+
+struct snd_usb_platform_ops {
+	void (*connect_cb)(struct snd_usb_audio *chip);
+	void (*disconnect_cb)(struct snd_usb_audio *chip);
+	void (*suspend_cb)(struct usb_interface *intf, pm_message_t message);
+	void (*resume_cb)(struct usb_interface *intf);
+};
+
+struct snd_usb_stream *
+snd_usb_find_suppported_substream(int card_idx, struct snd_pcm_hw_params *params,
+				  int direction);
+
+int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops);
+int snd_usb_unregister_platform_ops(void);
+
+void snd_usb_rediscover_devices(void);
+#endif /* __USBAUDIO_CARD_H */
diff --git a/sound/usb/clock.c b/sound/usb/clock.c
new file mode 100644
index 000000000..34832183a
--- /dev/null
+++ b/sound/usb/clock.c
@@ -0,0 +1,694 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Clock domain and sample rate management functions
+ */
+
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "helper.h"
+#include "clock.h"
+#include "quirks.h"
+
+union uac23_clock_source_desc {
+	struct uac_clock_source_descriptor v2;
+	struct uac3_clock_source_descriptor v3;
+};
+
+union uac23_clock_selector_desc {
+	struct uac_clock_selector_descriptor v2;
+	struct uac3_clock_selector_descriptor v3;
+};
+
+union uac23_clock_multiplier_desc {
+	struct uac_clock_multiplier_descriptor v2;
+	struct uac_clock_multiplier_descriptor v3;
+};
+
+/* check whether the descriptor bLength has the minimal length */
+#define DESC_LENGTH_CHECK(p, proto) \
+	((proto) == UAC_VERSION_3 ? \
+	 ((p)->v3.bLength >= sizeof((p)->v3)) :	\
+	 ((p)->v2.bLength >= sizeof((p)->v2)))
+
+#define GET_VAL(p, proto, field) \
+	((proto) == UAC_VERSION_3 ? (p)->v3.field : (p)->v2.field)
+
+static void *find_uac_clock_desc(struct usb_host_interface *iface, int id,
+				 bool (*validator)(void *, int, int),
+				 u8 type, int proto)
+{
+	void *cs = NULL;
+
+	while ((cs = snd_usb_find_csint_desc(iface->extra, iface->extralen,
+					     cs, type))) {
+		if (validator(cs, id, proto))
+			return cs;
+	}
+
+	return NULL;
+}
+
+static bool validate_clock_source(void *p, int id, int proto)
+{
+	union uac23_clock_source_desc *cs = p;
+
+	if (!DESC_LENGTH_CHECK(cs, proto))
+		return false;
+	return GET_VAL(cs, proto, bClockID) == id;
+}
+
+static bool validate_clock_selector(void *p, int id, int proto)
+{
+	union uac23_clock_selector_desc *cs = p;
+
+	if (!DESC_LENGTH_CHECK(cs, proto))
+		return false;
+	if (GET_VAL(cs, proto, bClockID) != id)
+		return false;
+	/* additional length check for baCSourceID array (in bNrInPins size)
+	 * and two more fields (which sizes depend on the protocol)
+	 */
+	if (proto == UAC_VERSION_3)
+		return cs->v3.bLength >= sizeof(cs->v3) + cs->v3.bNrInPins +
+			4 /* bmControls */ + 2 /* wCSelectorDescrStr */;
+	else
+		return cs->v2.bLength >= sizeof(cs->v2) + cs->v2.bNrInPins +
+			1 /* bmControls */ + 1 /* iClockSelector */;
+}
+
+static bool validate_clock_multiplier(void *p, int id, int proto)
+{
+	union uac23_clock_multiplier_desc *cs = p;
+
+	if (!DESC_LENGTH_CHECK(cs, proto))
+		return false;
+	return GET_VAL(cs, proto, bClockID) == id;
+}
+
+#define DEFINE_FIND_HELPER(name, obj, validator, type2, type3)		\
+static obj *name(struct snd_usb_audio *chip, int id,	\
+				const struct audioformat *fmt)	\
+{									\
+	struct usb_host_interface *ctrl_intf =	\
+		snd_usb_find_ctrl_interface(chip, fmt->iface); \
+	return find_uac_clock_desc(ctrl_intf, id, validator,	\
+				   fmt->protocol == UAC_VERSION_3 ? (type3) : (type2), \
+				   fmt->protocol);				\
+}
+
+DEFINE_FIND_HELPER(snd_usb_find_clock_source,
+		   union uac23_clock_source_desc, validate_clock_source,
+		   UAC2_CLOCK_SOURCE, UAC3_CLOCK_SOURCE);
+DEFINE_FIND_HELPER(snd_usb_find_clock_selector,
+		   union uac23_clock_selector_desc, validate_clock_selector,
+		   UAC2_CLOCK_SELECTOR, UAC3_CLOCK_SELECTOR);
+DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier,
+		   union uac23_clock_multiplier_desc, validate_clock_multiplier,
+		   UAC2_CLOCK_MULTIPLIER, UAC3_CLOCK_MULTIPLIER);
+
+static int uac_clock_selector_get_val(struct snd_usb_audio *chip,
+				int selector_id, int iface_no)
+{
+	struct usb_host_interface *ctrl_intf;
+	unsigned char buf;
+	int ret;
+
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, iface_no);
+	ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
+			      UAC2_CS_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			      UAC2_CX_CLOCK_SELECTOR << 8,
+			      snd_usb_ctrl_intf(ctrl_intf) | (selector_id << 8),
+			      &buf, sizeof(buf));
+
+	if (ret < 0)
+		return ret;
+
+	return buf;
+}
+
+static int uac_clock_selector_set_val(struct snd_usb_audio *chip,
+					int selector_id, unsigned char pin, int iface_no)
+{
+	struct usb_host_interface *ctrl_intf;
+	int ret;
+
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, iface_no);
+	ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
+			      UAC2_CS_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			      UAC2_CX_CLOCK_SELECTOR << 8,
+			      snd_usb_ctrl_intf(ctrl_intf) | (selector_id << 8),
+			      &pin, sizeof(pin));
+	if (ret < 0)
+		return ret;
+
+	if (ret != sizeof(pin)) {
+		usb_audio_err(chip,
+			"setting selector (id %d) unexpected length %d\n",
+			selector_id, ret);
+		return -EINVAL;
+	}
+
+	ret = uac_clock_selector_get_val(chip, selector_id, iface_no);
+	if (ret < 0)
+		return ret;
+
+	if (ret != pin) {
+		usb_audio_err(chip,
+			"setting selector (id %d) to %x failed (current: %d)\n",
+			selector_id, pin, ret);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static bool uac_clock_source_is_valid_quirk(struct snd_usb_audio *chip,
+					    const struct audioformat *fmt,
+					    int source_id)
+{
+	bool ret = false;
+	int count;
+	unsigned char data;
+	struct usb_device *dev = chip->dev;
+	union uac23_clock_source_desc *cs_desc;
+	struct usb_host_interface *ctrl_intf;
+
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, fmt->iface);
+	cs_desc = snd_usb_find_clock_source(chip, source_id, fmt);
+	if (!cs_desc)
+		return false;
+
+	if (fmt->protocol == UAC_VERSION_2) {
+		/*
+		 * Assume the clock is valid if clock source supports only one
+		 * single sample rate, the terminal is connected directly to it
+		 * (there is no clock selector) and clock type is internal.
+		 * This is to deal with some Denon DJ controllers that always
+		 * reports that clock is invalid.
+		 */
+		if (fmt->nr_rates == 1 &&
+		    (fmt->clock & 0xff) == cs_desc->v2.bClockID &&
+		    (cs_desc->v2.bmAttributes & 0x3) !=
+				UAC_CLOCK_SOURCE_TYPE_EXT)
+			return true;
+	}
+
+	/*
+	 * Quirk for older MOTU AVB / hybrid interfaces
+	 *
+	 * These devices take more than 2 seconds to switch sample rate or
+	 * clock source. During this period the clock validity request
+	 * returns false, causing ALSA to fail prematurely.
+	 *
+	 * Affected models (all use vendor 0x07fd):
+	 *   - MicroBook IIc          → 0x0004
+	 *   - 1248, 624, 8A, UltraLite AVB, 8M, 16A, ... → 0x0005
+	 */
+	if (chip->usb_id == USB_ID(0x07fd, 0x0004) ||  /* MicroBook IIc */
+	    chip->usb_id == USB_ID(0x07fd, 0x0005)) {  /* 1248 / 624 / 8A / UltraLite AVB / ... */
+		count = 0;
+
+		while ((!ret) && (count < 50)) {
+			int err;
+
+			msleep(100);
+
+			err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
+					      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+					      UAC2_CS_CONTROL_CLOCK_VALID << 8,
+					      snd_usb_ctrl_intf(ctrl_intf) | (source_id << 8),
+					      &data, sizeof(data));
+			if (err < 0) {
+				dev_warn(&dev->dev,
+					 "%s(): cannot get clock validity for id %d\n",
+					   __func__, source_id);
+				return false;
+			}
+
+			ret = !!data;
+			count++;
+		}
+	}
+
+	return ret;
+}
+
+static bool uac_clock_source_is_valid(struct snd_usb_audio *chip,
+				      const struct audioformat *fmt,
+				      int source_id)
+{
+	int err;
+	unsigned char data;
+	struct usb_device *dev = chip->dev;
+	u32 bmControls;
+	union uac23_clock_source_desc *cs_desc;
+	struct usb_host_interface *ctrl_intf;
+
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, fmt->iface);
+	cs_desc = snd_usb_find_clock_source(chip, source_id, fmt);
+	if (!cs_desc)
+		return false;
+
+	if (fmt->protocol == UAC_VERSION_3)
+		bmControls = le32_to_cpu(cs_desc->v3.bmControls);
+	else
+		bmControls = cs_desc->v2.bmControls;
+
+	/* If a clock source can't tell us whether it's valid, we assume it is */
+	if (!uac_v2v3_control_is_readable(bmControls,
+				      UAC2_CS_CONTROL_CLOCK_VALID))
+		return true;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			      UAC2_CS_CONTROL_CLOCK_VALID << 8,
+			      snd_usb_ctrl_intf(ctrl_intf) | (source_id << 8),
+			      &data, sizeof(data));
+
+	if (err < 0) {
+		dev_warn(&dev->dev,
+			 "%s(): cannot get clock validity for id %d\n",
+			   __func__, source_id);
+		return false;
+	}
+
+	if (data)
+		return true;
+	else
+		return uac_clock_source_is_valid_quirk(chip, fmt, source_id);
+}
+
+static int __uac_clock_find_source(struct snd_usb_audio *chip,
+				   const struct audioformat *fmt, int entity_id,
+				   unsigned long *visited, bool validate)
+{
+	union uac23_clock_source_desc *source;
+	union uac23_clock_selector_desc *selector;
+	union uac23_clock_multiplier_desc *multiplier;
+	int ret, i, cur, err, pins, clock_id;
+	const u8 *sources;
+	int proto = fmt->protocol;
+	bool readable, writeable;
+	u32 bmControls;
+
+	entity_id &= 0xff;
+
+	if (test_and_set_bit(entity_id, visited)) {
+		usb_audio_warn(chip,
+			 "%s(): recursive clock topology detected, id %d.\n",
+			 __func__, entity_id);
+		return -EINVAL;
+	}
+
+	/* first, see if the ID we're looking at is a clock source already */
+	source = snd_usb_find_clock_source(chip, entity_id, fmt);
+	if (source) {
+		entity_id = GET_VAL(source, proto, bClockID);
+		if (validate && !uac_clock_source_is_valid(chip, fmt,
+								entity_id)) {
+			usb_audio_err(chip,
+				"clock source %d is not valid, cannot use\n",
+				entity_id);
+			return -ENXIO;
+		}
+		return entity_id;
+	}
+
+	selector = snd_usb_find_clock_selector(chip, entity_id, fmt);
+	if (selector) {
+		pins = GET_VAL(selector, proto, bNrInPins);
+		clock_id = GET_VAL(selector, proto, bClockID);
+		sources = GET_VAL(selector, proto, baCSourceID);
+		cur = 0;
+
+		if (proto == UAC_VERSION_3)
+			bmControls = le32_to_cpu(*(__le32 *)(&selector->v3.baCSourceID[0] + pins));
+		else
+			bmControls = *(__u8 *)(&selector->v2.baCSourceID[0] + pins);
+
+		readable = uac_v2v3_control_is_readable(bmControls,
+							UAC2_CX_CLOCK_SELECTOR);
+		writeable = uac_v2v3_control_is_writeable(bmControls,
+							  UAC2_CX_CLOCK_SELECTOR);
+
+		if (pins == 1) {
+			ret = 1;
+			goto find_source;
+		}
+
+		/* for now just warn about buggy device */
+		if (!readable)
+			usb_audio_warn(chip,
+				"%s(): clock selector control is not readable, id %d\n",
+				__func__, clock_id);
+
+		/* the entity ID we are looking at is a selector.
+		 * find out what it currently selects */
+		ret = uac_clock_selector_get_val(chip, clock_id, fmt->iface);
+		if (ret < 0) {
+			if (!chip->autoclock)
+				return ret;
+			goto find_others;
+		}
+
+		/* Selector values are one-based */
+
+		if (ret > pins || ret < 1) {
+			usb_audio_err(chip,
+				"%s(): selector reported illegal value, id %d, ret %d\n",
+				__func__, clock_id, ret);
+
+			if (!chip->autoclock)
+				return -EINVAL;
+			goto find_others;
+		}
+
+	find_source:
+		cur = ret;
+		ret = __uac_clock_find_source(chip, fmt,
+					      sources[ret - 1],
+					      visited, validate);
+		if (ret > 0) {
+			/* Skip setting clock selector again for some devices */
+			if (chip->quirk_flags & QUIRK_FLAG_SKIP_CLOCK_SELECTOR ||
+			    !writeable)
+				return ret;
+			err = uac_clock_selector_set_val(chip, entity_id, cur, fmt->iface);
+			if (err < 0) {
+				if (pins == 1) {
+					usb_audio_dbg(chip,
+						      "%s(): selector returned an error, "
+						      "assuming a firmware bug, id %d, ret %d\n",
+						      __func__, clock_id, err);
+					return ret;
+				}
+				return err;
+			}
+		}
+
+		if (!validate || ret > 0 || !chip->autoclock)
+			return ret;
+
+	find_others:
+		if (!writeable)
+			return -ENXIO;
+
+		/* The current clock source is invalid, try others. */
+		for (i = 1; i <= pins; i++) {
+			if (i == cur)
+				continue;
+
+			ret = __uac_clock_find_source(chip, fmt,
+						      sources[i - 1],
+						      visited, true);
+			if (ret < 0)
+				continue;
+
+			err = uac_clock_selector_set_val(chip, entity_id, i, fmt->iface);
+			if (err < 0)
+				continue;
+
+			usb_audio_info(chip,
+				 "found and selected valid clock source %d\n",
+				 ret);
+			return ret;
+		}
+
+		return -ENXIO;
+	}
+
+	/* FIXME: multipliers only act as pass-thru element for now */
+	multiplier = snd_usb_find_clock_multiplier(chip, entity_id, fmt);
+	if (multiplier)
+		return __uac_clock_find_source(chip, fmt,
+					       GET_VAL(multiplier, proto, bCSourceID),
+					       visited, validate);
+
+	return -EINVAL;
+}
+
+/*
+ * For all kinds of sample rate settings and other device queries,
+ * the clock source (end-leaf) must be used. However, clock selectors,
+ * clock multipliers and sample rate converters may be specified as
+ * clock source input to terminal. This functions walks the clock path
+ * to its end and tries to find the source.
+ *
+ * The 'visited' bitfield is used internally to detect recursive loops.
+ *
+ * Returns the clock source UnitID (>=0) on success, or an error.
+ */
+int snd_usb_clock_find_source(struct snd_usb_audio *chip,
+			      const struct audioformat *fmt, bool validate)
+{
+	DECLARE_BITMAP(visited, 256);
+	memset(visited, 0, sizeof(visited));
+
+	switch (fmt->protocol) {
+	case UAC_VERSION_2:
+	case UAC_VERSION_3:
+		return __uac_clock_find_source(chip, fmt, fmt->clock, visited,
+					       validate);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int set_sample_rate_v1(struct snd_usb_audio *chip,
+			      const struct audioformat *fmt, int rate)
+{
+	struct usb_device *dev = chip->dev;
+	unsigned char data[3];
+	int err, crate;
+
+	/* if endpoint doesn't have sampling rate control, bail out */
+	if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
+		return 0;
+
+	data[0] = rate;
+	data[1] = rate >> 8;
+	data[2] = rate >> 16;
+	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
+			      UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
+			      fmt->endpoint, data, sizeof(data));
+	if (err < 0) {
+		dev_err(&dev->dev, "%d:%d: cannot set freq %d to ep %#x\n",
+			fmt->iface, fmt->altsetting, rate, fmt->endpoint);
+		return err;
+	}
+
+	/* Don't check the sample rate for devices which we know don't
+	 * support reading */
+	if (chip->quirk_flags & QUIRK_FLAG_GET_SAMPLE_RATE)
+		return 0;
+	/* the firmware is likely buggy, don't repeat to fail too many times */
+	if (chip->sample_rate_read_error > 2)
+		return 0;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
+			      UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
+			      fmt->endpoint, data, sizeof(data));
+	if (err < 0) {
+		dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
+			fmt->iface, fmt->altsetting, fmt->endpoint);
+		chip->sample_rate_read_error++;
+		return 0; /* some devices don't support reading */
+	}
+
+	crate = data[0] | (data[1] << 8) | (data[2] << 16);
+	if (!crate) {
+		dev_info(&dev->dev, "failed to read current rate; disabling the check\n");
+		chip->sample_rate_read_error = 3; /* three strikes, see above */
+		return 0;
+	}
+
+	if (crate != rate) {
+		dev_warn(&dev->dev, "current rate %d is different from the runtime rate %d\n", crate, rate);
+		// runtime->rate = crate;
+	}
+
+	return 0;
+}
+
+static int get_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
+			      int altsetting, int clock)
+{
+	struct usb_device *dev = chip->dev;
+	__le32 data;
+	int err;
+	struct usb_host_interface *ctrl_intf;
+
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, iface);
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			      UAC2_CS_CONTROL_SAM_FREQ << 8,
+			      snd_usb_ctrl_intf(ctrl_intf) | (clock << 8),
+			      &data, sizeof(data));
+	if (err < 0) {
+		dev_warn(&dev->dev, "%d:%d: cannot get freq (v2/v3): err %d\n",
+			 iface, altsetting, err);
+		return 0;
+	}
+
+	return le32_to_cpu(data);
+}
+
+/*
+ * Try to set the given sample rate:
+ *
+ * Return 0 if the clock source is read-only, the actual rate on success,
+ * or a negative error code.
+ *
+ * This function gets called from format.c to validate each sample rate, too.
+ * Hence no message is shown upon error
+ */
+int snd_usb_set_sample_rate_v2v3(struct snd_usb_audio *chip,
+				 const struct audioformat *fmt,
+				 int clock, int rate)
+{
+	bool writeable;
+	u32 bmControls;
+	__le32 data;
+	int err;
+	union uac23_clock_source_desc *cs_desc;
+	struct usb_host_interface *ctrl_intf;
+
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, fmt->iface);
+	cs_desc = snd_usb_find_clock_source(chip, clock, fmt);
+
+	if (!cs_desc)
+		return 0;
+
+	if (fmt->protocol == UAC_VERSION_3)
+		bmControls = le32_to_cpu(cs_desc->v3.bmControls);
+	else
+		bmControls = cs_desc->v2.bmControls;
+
+	writeable = uac_v2v3_control_is_writeable(bmControls,
+						  UAC2_CS_CONTROL_SAM_FREQ);
+	if (!writeable)
+		return 0;
+
+	data = cpu_to_le32(rate);
+	err = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC2_CS_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
+			      UAC2_CS_CONTROL_SAM_FREQ << 8,
+			      snd_usb_ctrl_intf(ctrl_intf) | (clock << 8),
+			      &data, sizeof(data));
+	if (err < 0)
+		return err;
+
+	return get_sample_rate_v2v3(chip, fmt->iface, fmt->altsetting, clock);
+}
+
+static int set_sample_rate_v2v3(struct snd_usb_audio *chip,
+				const struct audioformat *fmt, int rate)
+{
+	int cur_rate, prev_rate = 0;
+	int clock;
+
+	/* First, try to find a valid clock. This may trigger
+	 * automatic clock selection if the current clock is not
+	 * valid.
+	 */
+	clock = snd_usb_clock_find_source(chip, fmt, true);
+	if (clock < 0) {
+		/* We did not find a valid clock, but that might be
+		 * because the current sample rate does not match an
+		 * external clock source. Try again without validation
+		 * and we will do another validation after setting the
+		 * rate.
+		 */
+		clock = snd_usb_clock_find_source(chip, fmt, false);
+
+		/* Hardcoded sample rates */
+		if (chip->quirk_flags & QUIRK_FLAG_IGNORE_CLOCK_SOURCE)
+			return 0;
+
+		if (clock < 0)
+			return clock;
+	}
+
+	if (!(chip->quirk_flags & QUIRK_FLAG_ALWAYS_SET_RATE)) {
+		prev_rate = get_sample_rate_v2v3(chip, fmt->iface,
+						 fmt->altsetting, clock);
+		if (prev_rate == rate)
+			goto validation;
+	}
+
+	cur_rate = snd_usb_set_sample_rate_v2v3(chip, fmt, clock, rate);
+	if (cur_rate < 0) {
+		usb_audio_err(chip,
+			      "%d:%d: cannot set freq %d (v2/v3): err %d\n",
+			      fmt->iface, fmt->altsetting, rate, cur_rate);
+		return cur_rate;
+	}
+
+	if (!cur_rate)
+		cur_rate = prev_rate;
+
+	if (cur_rate != rate) {
+		usb_audio_dbg(chip,
+			      "%d:%d: freq mismatch: req %d, clock runs @%d\n",
+			      fmt->iface, fmt->altsetting, rate, cur_rate);
+		/* continue processing */
+	}
+
+	/* FIXME - TEAC devices require the immediate interface setup */
+	if (USB_ID_VENDOR(chip->usb_id) == 0x0644) {
+		bool cur_base_48k = (rate % 48000 == 0);
+		bool prev_base_48k = (prev_rate % 48000 == 0);
+		if (cur_base_48k != prev_base_48k) {
+			usb_set_interface(chip->dev, fmt->iface, fmt->altsetting);
+			if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
+				msleep(50);
+		}
+	}
+
+validation:
+	/* validate clock after rate change */
+	if (!uac_clock_source_is_valid(chip, fmt, clock))
+		return -ENXIO;
+	return 0;
+}
+
+int snd_usb_init_sample_rate(struct snd_usb_audio *chip,
+			     const struct audioformat *fmt, int rate)
+{
+	usb_audio_dbg(chip, "%d:%d Set sample rate %d, clock %d\n",
+		      fmt->iface, fmt->altsetting, rate, fmt->clock);
+
+	switch (fmt->protocol) {
+	case UAC_VERSION_1:
+	default:
+		return set_sample_rate_v1(chip, fmt, rate);
+
+	case UAC_VERSION_3:
+		if (chip->badd_profile >= UAC3_FUNCTION_SUBCLASS_GENERIC_IO) {
+			if (rate != UAC3_BADD_SAMPLING_RATE)
+				return -ENXIO;
+			else
+				return 0;
+		}
+		fallthrough;
+	case UAC_VERSION_2:
+		return set_sample_rate_v2v3(chip, fmt, rate);
+	}
+}
+
diff --git a/sound/usb/clock.h b/sound/usb/clock.h
new file mode 100644
index 000000000..ed9fc2dc0
--- /dev/null
+++ b/sound/usb/clock.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_CLOCK_H
+#define __USBAUDIO_CLOCK_H
+
+int snd_usb_init_sample_rate(struct snd_usb_audio *chip,
+			     const struct audioformat *fmt, int rate);
+
+int snd_usb_clock_find_source(struct snd_usb_audio *chip,
+			      const struct audioformat *fmt, bool validate);
+
+int snd_usb_set_sample_rate_v2v3(struct snd_usb_audio *chip,
+				 const struct audioformat *fmt,
+				 int clock, int rate);
+
+#endif /* __USBAUDIO_CLOCK_H */
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
new file mode 100644
index 000000000..879d04515
--- /dev/null
+++ b/sound/usb/endpoint.c
@@ -0,0 +1,1926 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/ratelimit.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/slab.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include "usbaudio.h"
+#include "helper.h"
+#include "card.h"
+#include "endpoint.h"
+#include "pcm.h"
+#include "clock.h"
+#include "quirks.h"
+
+enum {
+	EP_STATE_STOPPED,
+	EP_STATE_RUNNING,
+	EP_STATE_STOPPING,
+};
+
+/* interface refcounting */
+struct snd_usb_iface_ref {
+	unsigned char iface;
+	bool need_setup;
+	int opened;
+	int altset;
+	struct list_head list;
+};
+
+/* clock refcounting */
+struct snd_usb_clock_ref {
+	unsigned char clock;
+	atomic_t locked;
+	int opened;
+	int rate;
+	bool need_setup;
+	struct list_head list;
+};
+
+/*
+ * snd_usb_endpoint is a model that abstracts everything related to an
+ * USB endpoint and its streaming.
+ *
+ * There are functions to activate and deactivate the streaming URBs and
+ * optional callbacks to let the pcm logic handle the actual content of the
+ * packets for playback and record. Thus, the bus streaming and the audio
+ * handlers are fully decoupled.
+ *
+ * There are two different types of endpoints in audio applications.
+ *
+ * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
+ * inbound and outbound traffic.
+ *
+ * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
+ * expect the payload to carry Q10.14 / Q16.16 formatted sync information
+ * (3 or 4 bytes).
+ *
+ * Each endpoint has to be configured prior to being used by calling
+ * snd_usb_endpoint_set_params().
+ *
+ * The model incorporates a reference counting, so that multiple users
+ * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
+ * only the first user will effectively start the URBs, and only the last
+ * one to stop it will tear the URBs down again.
+ */
+
+/*
+ * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
+ * this will overflow at approx 524 kHz
+ */
+static inline unsigned get_usb_full_speed_rate(unsigned int rate)
+{
+	return ((rate << 13) + 62) / 125;
+}
+
+/*
+ * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
+ * this will overflow at approx 4 MHz
+ */
+static inline unsigned get_usb_high_speed_rate(unsigned int rate)
+{
+	return ((rate << 10) + 62) / 125;
+}
+
+/*
+ * release a urb data
+ */
+static void release_urb_ctx(struct snd_urb_ctx *u)
+{
+	if (u->urb && u->buffer_size)
+		usb_free_coherent(u->ep->chip->dev, u->buffer_size,
+				  u->urb->transfer_buffer,
+				  u->urb->transfer_dma);
+	usb_free_urb(u->urb);
+	u->urb = NULL;
+	u->buffer_size = 0;
+}
+
+static const char *usb_error_string(int err)
+{
+	switch (err) {
+	case -ENODEV:
+		return "no device";
+	case -ENOENT:
+		return "endpoint not enabled";
+	case -EPIPE:
+		return "endpoint stalled";
+	case -ENOSPC:
+		return "not enough bandwidth";
+	case -ESHUTDOWN:
+		return "device disabled";
+	case -EHOSTUNREACH:
+		return "device suspended";
+	case -EINVAL:
+	case -EAGAIN:
+	case -EFBIG:
+	case -EMSGSIZE:
+		return "internal error";
+	default:
+		return "unknown error";
+	}
+}
+
+static inline bool ep_state_running(struct snd_usb_endpoint *ep)
+{
+	return atomic_read(&ep->state) == EP_STATE_RUNNING;
+}
+
+static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
+{
+	return atomic_try_cmpxchg(&ep->state, &old, new);
+}
+
+/**
+ * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
+ *
+ * @ep: The snd_usb_endpoint
+ *
+ * Determine whether an endpoint is driven by an implicit feedback
+ * data endpoint source.
+ */
+int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
+{
+	return  ep->implicit_fb_sync && usb_pipeout(ep->pipe);
+}
+
+/*
+ * Return the number of samples to be sent in the next packet
+ * for streaming based on information derived from sync endpoints
+ *
+ * This won't be used for implicit feedback which takes the packet size
+ * returned from the sync source
+ */
+static int synced_next_packet_size(struct snd_usb_endpoint *ep,
+				   unsigned int avail)
+{
+	unsigned int phase;
+	int ret;
+
+	if (ep->fill_max)
+		return ep->maxframesize;
+
+	guard(spinlock_irqsave)(&ep->lock);
+	phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval);
+	ret = min(phase >> 16, ep->maxframesize);
+	if (avail && ret >= avail)
+		ret = -EAGAIN;
+	else
+		ep->phase = phase;
+	return ret;
+}
+
+/*
+ * Return the number of samples to be sent in the next packet
+ * for adaptive and synchronous endpoints
+ */
+static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
+{
+	unsigned int sample_accum;
+	int ret;
+
+	if (ep->fill_max)
+		return ep->maxframesize;
+
+	sample_accum = ep->sample_accum + ep->sample_rem;
+	if (sample_accum >= ep->pps) {
+		sample_accum -= ep->pps;
+		ret = ep->packsize[1];
+	} else {
+		ret = ep->packsize[0];
+	}
+	if (avail && ret >= avail)
+		ret = -EAGAIN;
+	else
+		ep->sample_accum = sample_accum;
+
+	return ret;
+}
+
+/*
+ * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
+ * in the next packet
+ *
+ * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN
+ * Exception: @avail = 0 for skipping the check.
+ */
+int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
+				      struct snd_urb_ctx *ctx, int idx,
+				      unsigned int avail)
+{
+	unsigned int packet;
+
+	packet = ctx->packet_size[idx];
+	if (packet) {
+		packet = min(packet, ep->maxframesize);
+		if (avail && packet >= avail)
+			return -EAGAIN;
+		return packet;
+	}
+
+	if (ep->sync_source)
+		return synced_next_packet_size(ep, avail);
+	else
+		return next_packet_size(ep, avail);
+}
+
+static void call_retire_callback(struct snd_usb_endpoint *ep,
+				 struct urb *urb)
+{
+	struct snd_usb_substream *data_subs;
+
+	data_subs = READ_ONCE(ep->data_subs);
+	if (data_subs && ep->retire_data_urb)
+		ep->retire_data_urb(data_subs, urb);
+}
+
+static void retire_outbound_urb(struct snd_usb_endpoint *ep,
+				struct snd_urb_ctx *urb_ctx)
+{
+	call_retire_callback(ep, urb_ctx->urb);
+}
+
+static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
+				    struct snd_usb_endpoint *sender,
+				    const struct urb *urb);
+
+static void retire_inbound_urb(struct snd_usb_endpoint *ep,
+			       struct snd_urb_ctx *urb_ctx)
+{
+	struct urb *urb = urb_ctx->urb;
+	struct snd_usb_endpoint *sync_sink;
+
+	if (unlikely(ep->skip_packets > 0)) {
+		ep->skip_packets--;
+		return;
+	}
+
+	sync_sink = READ_ONCE(ep->sync_sink);
+	if (sync_sink)
+		snd_usb_handle_sync_urb(sync_sink, ep, urb);
+
+	call_retire_callback(ep, urb);
+}
+
+static inline bool has_tx_length_quirk(struct snd_usb_audio *chip)
+{
+	return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH;
+}
+
+static int prepare_silent_urb(struct snd_usb_endpoint *ep,
+			      struct snd_urb_ctx *ctx)
+{
+	struct urb *urb = ctx->urb;
+	unsigned int offs = 0;
+	unsigned int extra = 0;
+	__le32 packet_length;
+	int i;
+
+	/* For tx_length_quirk, put packet length at start of packet */
+	if (has_tx_length_quirk(ep->chip))
+		extra = sizeof(packet_length);
+
+	for (i = 0; i < ctx->packets; ++i) {
+		int length;
+
+		length = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
+		if (length < 0)
+			return length;
+		length *= ep->stride; /* number of silent bytes */
+		if (offs + length + extra > ctx->buffer_size)
+			break;
+		urb->iso_frame_desc[i].offset = offs;
+		urb->iso_frame_desc[i].length = length + extra;
+		if (extra) {
+			packet_length = cpu_to_le32(length);
+			memcpy(urb->transfer_buffer + offs,
+			       &packet_length, sizeof(packet_length));
+			offs += extra;
+		}
+		memset(urb->transfer_buffer + offs,
+		       ep->silence_value, length);
+		offs += length;
+	}
+
+	if (!offs)
+		return -EPIPE;
+
+	urb->number_of_packets = i;
+	urb->transfer_buffer_length = offs;
+	ctx->queued = 0;
+	return 0;
+}
+
+/*
+ * Prepare a PLAYBACK urb for submission to the bus.
+ */
+static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
+				struct snd_urb_ctx *ctx,
+				bool in_stream_lock)
+{
+	struct urb *urb = ctx->urb;
+	unsigned char *cp = urb->transfer_buffer;
+	struct snd_usb_substream *data_subs;
+
+	urb->dev = ep->chip->dev; /* we need to set this at each time */
+
+	switch (ep->type) {
+	case SND_USB_ENDPOINT_TYPE_DATA:
+		data_subs = READ_ONCE(ep->data_subs);
+		if (data_subs && ep->prepare_data_urb)
+			return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
+		/* no data provider, so send silence */
+		return prepare_silent_urb(ep, ctx);
+
+	case SND_USB_ENDPOINT_TYPE_SYNC:
+		if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
+			/*
+			 * fill the length and offset of each urb descriptor.
+			 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
+			 */
+			urb->iso_frame_desc[0].length = 4;
+			urb->iso_frame_desc[0].offset = 0;
+			cp[0] = ep->freqn;
+			cp[1] = ep->freqn >> 8;
+			cp[2] = ep->freqn >> 16;
+			cp[3] = ep->freqn >> 24;
+		} else {
+			/*
+			 * fill the length and offset of each urb descriptor.
+			 * the fixed 10.14 frequency is passed through the pipe.
+			 */
+			urb->iso_frame_desc[0].length = 3;
+			urb->iso_frame_desc[0].offset = 0;
+			cp[0] = ep->freqn >> 2;
+			cp[1] = ep->freqn >> 10;
+			cp[2] = ep->freqn >> 18;
+		}
+
+		break;
+	}
+	return 0;
+}
+
+/*
+ * Prepare a CAPTURE or SYNC urb for submission to the bus.
+ */
+static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
+			       struct snd_urb_ctx *urb_ctx)
+{
+	int i, offs;
+	struct urb *urb = urb_ctx->urb;
+
+	urb->dev = ep->chip->dev; /* we need to set this at each time */
+
+	switch (ep->type) {
+	case SND_USB_ENDPOINT_TYPE_DATA:
+		offs = 0;
+		for (i = 0; i < urb_ctx->packets; i++) {
+			if (offs + ep->curpacksize > urb_ctx->buffer_size)
+				break;
+			urb->iso_frame_desc[i].offset = offs;
+			urb->iso_frame_desc[i].length = ep->curpacksize;
+			offs += ep->curpacksize;
+		}
+
+		urb->transfer_buffer_length = offs;
+		urb->number_of_packets = i;
+		break;
+
+	case SND_USB_ENDPOINT_TYPE_SYNC:
+		urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
+		urb->iso_frame_desc[0].offset = 0;
+		break;
+	}
+	return 0;
+}
+
+/* notify an error as XRUN to the assigned PCM data substream */
+static bool notify_xrun(struct snd_usb_endpoint *ep)
+{
+	struct snd_usb_substream *data_subs;
+	struct snd_pcm_substream *psubs;
+
+	data_subs = READ_ONCE(ep->data_subs);
+	if (!data_subs)
+		return false;
+	psubs = data_subs->pcm_substream;
+	if (psubs && psubs->runtime &&
+	    psubs->runtime->state == SNDRV_PCM_STATE_RUNNING) {
+		snd_pcm_stop_xrun(psubs);
+		return true;
+	}
+	return false;
+}
+
+static struct snd_usb_packet_info *
+next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
+{
+	struct snd_usb_packet_info *p;
+
+	p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
+		ARRAY_SIZE(ep->next_packet);
+	ep->next_packet_queued++;
+	return p;
+}
+
+static struct snd_usb_packet_info *
+next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
+{
+	struct snd_usb_packet_info *p;
+
+	p = ep->next_packet + ep->next_packet_head;
+	ep->next_packet_head++;
+	ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
+	ep->next_packet_queued--;
+	return p;
+}
+
+static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
+				    struct snd_urb_ctx *ctx)
+{
+	guard(spinlock_irqsave)(&ep->lock);
+	/* ctx may still be linked: a stale completion racing a stop/restart. */
+	if (list_empty(&ctx->ready_list))
+		list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
+}
+
+/*
+ * Send output urbs that have been prepared previously. URBs are dequeued
+ * from ep->ready_playback_urbs and in case there aren't any available
+ * or there are no packets that have been prepared, this function does
+ * nothing.
+ *
+ * The reason why the functionality of sending and preparing URBs is separated
+ * is that host controllers don't guarantee the order in which they return
+ * inbound and outbound packets to their submitters.
+ *
+ * This function is used both for implicit feedback endpoints and in low-
+ * latency playback mode.
+ */
+int snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
+				      bool in_stream_lock)
+{
+	bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
+
+	while (ep_state_running(ep)) {
+		struct snd_usb_packet_info *packet;
+		struct snd_urb_ctx *ctx = NULL;
+		int err;
+
+		scoped_guard(spinlock_irqsave, &ep->lock) {
+			if ((!implicit_fb || ep->next_packet_queued > 0) &&
+			    !list_empty(&ep->ready_playback_urbs)) {
+				/* take URB out of FIFO */
+				ctx = list_first_entry(&ep->ready_playback_urbs,
+						       struct snd_urb_ctx, ready_list);
+				list_del_init(&ctx->ready_list);
+				if (implicit_fb)
+					packet = next_packet_fifo_dequeue(ep);
+			}
+		}
+
+		if (ctx == NULL)
+			break;
+
+		/* copy over the length information */
+		if (implicit_fb) {
+			ctx->packets = min_t(int, packet->packets,
+					     ep->max_urb_packs);
+			memcpy(ctx->packet_size, packet->packet_size,
+			       ctx->packets * sizeof(packet->packet_size[0]));
+		}
+
+		/* call the data handler to fill in playback data */
+		err = prepare_outbound_urb(ep, ctx, in_stream_lock);
+		/* can be stopped during prepare callback */
+		if (unlikely(!ep_state_running(ep)))
+			break;
+		if (err < 0) {
+			/* push back to ready list again for -EAGAIN */
+			if (err == -EAGAIN) {
+				push_back_to_ready_list(ep, ctx);
+				break;
+			}
+
+			if (!in_stream_lock)
+				notify_xrun(ep);
+			return -EPIPE;
+		}
+
+		if (!atomic_read(&ep->chip->shutdown))
+			err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
+		else
+			err = -ENODEV;
+		if (err < 0) {
+			if (!atomic_read(&ep->chip->shutdown)) {
+				usb_audio_err(ep->chip,
+					      "Unable to submit urb #%d: %d at %s\n",
+					      ctx->index, err, __func__);
+				if (!in_stream_lock)
+					notify_xrun(ep);
+			}
+			return -EPIPE;
+		}
+
+		set_bit(ctx->index, &ep->active_mask);
+		atomic_inc(&ep->submitted_urbs);
+	}
+
+	return 0;
+}
+
+/*
+ * complete callback for urbs
+ */
+static void snd_complete_urb(struct urb *urb)
+{
+	struct snd_urb_ctx *ctx = urb->context;
+	struct snd_usb_endpoint *ep = ctx->ep;
+	int err;
+
+	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
+		     urb->status == -ENODEV ||		/* device removed */
+		     urb->status == -ECONNRESET ||	/* unlinked */
+		     urb->status == -ESHUTDOWN))	/* device disabled */
+		goto exit_clear;
+	/* device disconnected */
+	if (unlikely(atomic_read(&ep->chip->shutdown)))
+		goto exit_clear;
+
+	if (unlikely(!ep_state_running(ep)))
+		goto exit_clear;
+
+	if (usb_pipeout(ep->pipe)) {
+		retire_outbound_urb(ep, ctx);
+		/* can be stopped during retire callback */
+		if (unlikely(!ep_state_running(ep)))
+			goto exit_clear;
+
+		/* in low-latency and implicit-feedback modes, push back the
+		 * URB to ready list at first, then process as much as possible
+		 */
+		if (ep->lowlatency_playback ||
+		     snd_usb_endpoint_implicit_feedback_sink(ep)) {
+			push_back_to_ready_list(ep, ctx);
+			clear_bit(ctx->index, &ep->active_mask);
+			snd_usb_queue_pending_output_urbs(ep, false);
+			/* decrement at last, and check xrun */
+			if (atomic_dec_and_test(&ep->submitted_urbs) &&
+			    !snd_usb_endpoint_implicit_feedback_sink(ep))
+				notify_xrun(ep);
+			return;
+		}
+
+		/* in non-lowlatency mode, no error handling for prepare */
+		prepare_outbound_urb(ep, ctx, false);
+		/* can be stopped during prepare callback */
+		if (unlikely(!ep_state_running(ep)))
+			goto exit_clear;
+	} else {
+		retire_inbound_urb(ep, ctx);
+		/* can be stopped during retire callback */
+		if (unlikely(!ep_state_running(ep)))
+			goto exit_clear;
+
+		prepare_inbound_urb(ep, ctx);
+	}
+
+	if (!atomic_read(&ep->chip->shutdown))
+		err = usb_submit_urb(urb, GFP_ATOMIC);
+	else
+		err = -ENODEV;
+	if (err == 0)
+		return;
+
+	if (!atomic_read(&ep->chip->shutdown)) {
+		if (notify_xrun(ep))
+			usb_audio_err(ep->chip,
+				      "cannot submit urb (err = %d)\n", err);
+	}
+
+exit_clear:
+	clear_bit(ctx->index, &ep->active_mask);
+	atomic_dec(&ep->submitted_urbs);
+}
+
+/*
+ * Find or create a refcount object for the given interface
+ *
+ * The objects are released altogether in snd_usb_endpoint_free_all()
+ */
+static struct snd_usb_iface_ref *
+iface_ref_find(struct snd_usb_audio *chip, int iface)
+{
+	struct snd_usb_iface_ref *ip;
+
+	list_for_each_entry(ip, &chip->iface_ref_list, list)
+		if (ip->iface == iface)
+			return ip;
+
+	ip = kzalloc_obj(*ip);
+	if (!ip)
+		return NULL;
+	ip->iface = iface;
+	list_add_tail(&ip->list, &chip->iface_ref_list);
+	return ip;
+}
+
+/* Similarly, a refcount object for clock */
+static struct snd_usb_clock_ref *
+clock_ref_find(struct snd_usb_audio *chip, int clock)
+{
+	struct snd_usb_clock_ref *ref;
+
+	list_for_each_entry(ref, &chip->clock_ref_list, list)
+		if (ref->clock == clock)
+			return ref;
+
+	ref = kzalloc_obj(*ref);
+	if (!ref)
+		return NULL;
+	ref->clock = clock;
+	atomic_set(&ref->locked, 0);
+	list_add_tail(&ref->list, &chip->clock_ref_list);
+	return ref;
+}
+
+/*
+ * Get the existing endpoint object corresponding EP
+ * Returns NULL if not present.
+ */
+struct snd_usb_endpoint *
+snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
+{
+	struct snd_usb_endpoint *ep;
+
+	list_for_each_entry(ep, &chip->ep_list, list) {
+		if (ep->ep_num == ep_num)
+			return ep;
+	}
+
+	return NULL;
+}
+
+#define ep_type_name(type) \
+	(type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
+
+/**
+ * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
+ *
+ * @chip: The chip
+ * @ep_num: The number of the endpoint to use
+ * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
+ *
+ * If the requested endpoint has not been added to the given chip before,
+ * a new instance is created.
+ *
+ * Returns zero on success or a negative error code.
+ *
+ * New endpoints will be added to chip->ep_list and freed by
+ * calling snd_usb_endpoint_free_all().
+ *
+ * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
+ * bNumEndpoints > 1 beforehand.
+ */
+int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
+{
+	struct snd_usb_endpoint *ep;
+	bool is_playback;
+
+	ep = snd_usb_get_endpoint(chip, ep_num);
+	if (ep)
+		return 0;
+
+	usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
+		      ep_type_name(type),
+		      ep_num);
+	ep = kzalloc_obj(*ep);
+	if (!ep)
+		return -ENOMEM;
+
+	ep->chip = chip;
+	spin_lock_init(&ep->lock);
+	ep->type = type;
+	ep->ep_num = ep_num;
+	INIT_LIST_HEAD(&ep->ready_playback_urbs);
+	atomic_set(&ep->submitted_urbs, 0);
+
+	is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
+	ep_num &= USB_ENDPOINT_NUMBER_MASK;
+	if (is_playback)
+		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
+	else
+		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
+
+	list_add_tail(&ep->list, &chip->ep_list);
+	return 0;
+}
+
+/* Set up syncinterval and maxsyncsize for a sync EP */
+static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
+				      struct snd_usb_endpoint *ep)
+{
+	struct usb_host_interface *alts;
+	struct usb_endpoint_descriptor *desc;
+
+	alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
+	if (!alts)
+		return;
+
+	desc = get_endpoint(alts, ep->ep_idx);
+	if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
+	    desc->bRefresh >= 1 && desc->bRefresh <= 9)
+		ep->syncinterval = desc->bRefresh;
+	else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
+		ep->syncinterval = 1;
+	else if (desc->bInterval >= 1 && desc->bInterval <= 16)
+		ep->syncinterval = desc->bInterval - 1;
+	else
+		ep->syncinterval = 3;
+
+	ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
+}
+
+static bool endpoint_compatible(struct snd_usb_endpoint *ep,
+				const struct audioformat *fp,
+				const struct snd_pcm_hw_params *params)
+{
+	if (!ep->opened)
+		return false;
+	if (ep->cur_audiofmt != fp)
+		return false;
+	if (ep->cur_rate != params_rate(params) ||
+	    ep->cur_format != params_format(params) ||
+	    ep->cur_period_frames != params_period_size(params) ||
+	    ep->cur_buffer_periods != params_periods(params))
+		return false;
+	return true;
+}
+
+/*
+ * Check whether the given fp and hw params are compatible with the current
+ * setup of the target EP for implicit feedback sync
+ */
+bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
+				 struct snd_usb_endpoint *ep,
+				 const struct audioformat *fp,
+				 const struct snd_pcm_hw_params *params)
+{
+	guard(mutex)(&chip->mutex);
+	return endpoint_compatible(ep, fp, params);
+}
+
+/*
+ * snd_usb_endpoint_open: Open the endpoint
+ *
+ * Called from hw_params to assign the endpoint to the substream.
+ * It's reference-counted, and only the first opener is allowed to set up
+ * arbitrary parameters.  The later opener must be compatible with the
+ * former opened parameters.
+ * The endpoint needs to be closed via snd_usb_endpoint_close() later.
+ *
+ * Note that this function doesn't configure the endpoint.  The substream
+ * needs to set it up later via snd_usb_endpoint_set_params() and
+ * snd_usb_endpoint_prepare().
+ */
+struct snd_usb_endpoint *
+snd_usb_endpoint_open(struct snd_usb_audio *chip,
+		      const struct audioformat *fp,
+		      const struct snd_pcm_hw_params *params,
+		      bool is_sync_ep,
+		      bool fixed_rate)
+{
+	struct snd_usb_endpoint *ep;
+	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
+
+	guard(mutex)(&chip->mutex);
+	ep = snd_usb_get_endpoint(chip, ep_num);
+	if (!ep) {
+		usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
+		return NULL;
+	}
+
+	if (!ep->opened) {
+		if (is_sync_ep) {
+			ep->iface = fp->sync_iface;
+			ep->altsetting = fp->sync_altsetting;
+			ep->ep_idx = fp->sync_ep_idx;
+		} else {
+			ep->iface = fp->iface;
+			ep->altsetting = fp->altsetting;
+			ep->ep_idx = fp->ep_idx;
+		}
+		usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
+			      ep_num, ep->iface, ep->altsetting, ep->ep_idx);
+
+		ep->iface_ref = iface_ref_find(chip, ep->iface);
+		if (!ep->iface_ref)
+			return NULL;
+
+		if (fp->protocol != UAC_VERSION_1) {
+			ep->clock_ref = clock_ref_find(chip, fp->clock);
+			if (!ep->clock_ref)
+				return NULL;
+			ep->clock_ref->opened++;
+		}
+
+		ep->cur_audiofmt = fp;
+		ep->cur_channels = fp->channels;
+		ep->cur_rate = params_rate(params);
+		ep->cur_format = params_format(params);
+		ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
+			ep->cur_channels / 8;
+		ep->cur_period_frames = params_period_size(params);
+		ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
+		ep->cur_buffer_periods = params_periods(params);
+
+		if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
+			endpoint_set_syncinterval(chip, ep);
+
+		ep->implicit_fb_sync = fp->implicit_fb;
+		ep->need_setup = true;
+		ep->need_prepare = true;
+		ep->fixed_rate = fixed_rate;
+
+		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
+			      ep->cur_channels, ep->cur_rate,
+			      snd_pcm_format_name(ep->cur_format),
+			      ep->cur_period_bytes, ep->cur_buffer_periods,
+			      ep->implicit_fb_sync);
+
+	} else {
+		if (WARN_ON(!ep->iface_ref))
+			return NULL;
+
+		if (!endpoint_compatible(ep, fp, params)) {
+			usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
+				      ep_num);
+			return NULL;
+		}
+
+		usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
+			      ep_num, ep->opened);
+	}
+
+	if (!ep->iface_ref->opened++)
+		ep->iface_ref->need_setup = true;
+
+	ep->opened++;
+	return ep;
+}
+
+/*
+ * snd_usb_endpoint_set_sync: Link data and sync endpoints
+ *
+ * Pass NULL to sync_ep to unlink again
+ */
+void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
+			       struct snd_usb_endpoint *data_ep,
+			       struct snd_usb_endpoint *sync_ep)
+{
+	data_ep->sync_source = sync_ep;
+}
+
+/*
+ * Set data endpoint callbacks and the assigned data stream
+ *
+ * Called at PCM trigger and cleanups.
+ * Pass NULL to deactivate each callback.
+ */
+void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
+				   int (*prepare)(struct snd_usb_substream *subs,
+						  struct urb *urb,
+						  bool in_stream_lock),
+				   void (*retire)(struct snd_usb_substream *subs,
+						  struct urb *urb),
+				   struct snd_usb_substream *data_subs)
+{
+	ep->prepare_data_urb = prepare;
+	ep->retire_data_urb = retire;
+	if (data_subs)
+		ep->lowlatency_playback = data_subs->lowlatency_playback;
+	else
+		ep->lowlatency_playback = false;
+	WRITE_ONCE(ep->data_subs, data_subs);
+}
+
+static int endpoint_set_interface(struct snd_usb_audio *chip,
+				  struct snd_usb_endpoint *ep,
+				  bool set)
+{
+	int altset = set ? ep->altsetting : 0;
+	int err;
+	int retries = 0;
+	const int max_retries = 5;
+
+	if (ep->iface_ref->altset == altset)
+		return 0;
+	/* already disconnected? */
+	if (unlikely(atomic_read(&chip->shutdown)))
+		return -ENODEV;
+
+	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
+		      ep->iface, altset, ep->ep_num);
+retry:
+	err = usb_set_interface(chip->dev, ep->iface, altset);
+	if (err < 0) {
+		if (err == -EPROTO && ++retries <= max_retries) {
+			msleep(5 * (1 << (retries - 1)));
+			goto retry;
+		}
+		usb_audio_err_ratelimited(
+			chip, "%d:%d: usb_set_interface failed (%d)\n",
+			ep->iface, altset, err);
+		return err;
+	}
+
+	if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
+		msleep(50);
+	ep->iface_ref->altset = altset;
+	return 0;
+}
+
+/*
+ * snd_usb_endpoint_close: Close the endpoint
+ *
+ * Unreference the already opened endpoint via snd_usb_endpoint_open().
+ */
+void snd_usb_endpoint_close(struct snd_usb_audio *chip,
+			    struct snd_usb_endpoint *ep)
+{
+	guard(mutex)(&chip->mutex);
+	usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
+		      ep->ep_num, ep->opened);
+
+	if (!--ep->iface_ref->opened &&
+		!(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE))
+		endpoint_set_interface(chip, ep, false);
+
+	if (!--ep->opened) {
+		if (ep->clock_ref) {
+			if (!--ep->clock_ref->opened)
+				ep->clock_ref->rate = 0;
+		}
+		ep->iface = 0;
+		ep->altsetting = 0;
+		ep->cur_audiofmt = NULL;
+		ep->cur_rate = 0;
+		ep->iface_ref = NULL;
+		ep->clock_ref = NULL;
+		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
+	}
+}
+
+/* Prepare for suspening EP, called from the main suspend handler */
+void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
+{
+	ep->need_prepare = true;
+	if (ep->iface_ref)
+		ep->iface_ref->need_setup = true;
+	if (ep->clock_ref)
+		ep->clock_ref->rate = 0;
+}
+
+/*
+ *  wait until all urbs are processed.
+ */
+static int wait_clear_urbs(struct snd_usb_endpoint *ep)
+{
+	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
+	int alive;
+
+	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
+		return 0;
+
+	do {
+		alive = atomic_read(&ep->submitted_urbs);
+		if (!alive)
+			break;
+
+		schedule_timeout_uninterruptible(1);
+	} while (time_before(jiffies, end_time));
+
+	if (alive)
+		usb_audio_err(ep->chip,
+			"timeout: still %d active urbs on EP #%x\n",
+			alive, ep->ep_num);
+
+	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
+		ep->sync_sink = NULL;
+		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
+	}
+
+	return 0;
+}
+
+/* sync the pending stop operation;
+ * this function itself doesn't trigger the stop operation
+ */
+void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
+{
+	if (ep)
+		wait_clear_urbs(ep);
+}
+
+/*
+ * Stop active urbs
+ *
+ * This function moves the EP to STOPPING state if it's being RUNNING.
+ */
+static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
+{
+	struct snd_urb_ctx *ctx, *n;
+	unsigned int i;
+
+	if (!force && atomic_read(&ep->running))
+		return -EBUSY;
+
+	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
+		return 0;
+
+	scoped_guard(spinlock_irqsave, &ep->lock) {
+		/* Unlink each ctx; INIT_LIST_HEAD() alone would leave them looking linked. */
+		list_for_each_entry_safe(ctx, n, &ep->ready_playback_urbs, ready_list)
+			list_del_init(&ctx->ready_list);
+		ep->next_packet_head = 0;
+		ep->next_packet_queued = 0;
+	}
+
+	if (keep_pending)
+		return 0;
+
+	for (i = 0; i < ep->nurbs; i++) {
+		if (test_bit(i, &ep->active_mask)) {
+			if (!test_and_set_bit(i, &ep->unlink_mask)) {
+				struct urb *u = ep->urb[i].urb;
+				usb_unlink_urb(u);
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * release an endpoint's urbs
+ */
+static int release_urbs(struct snd_usb_endpoint *ep, bool force)
+{
+	int i, err;
+
+	/* route incoming urbs to nirvana */
+	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
+
+	/* stop and unlink urbs */
+	err = stop_urbs(ep, force, false);
+	if (err)
+		return err;
+
+	wait_clear_urbs(ep);
+
+	for (i = 0; i < ep->nurbs; i++)
+		release_urb_ctx(&ep->urb[i]);
+
+	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
+			  ep->syncbuf, ep->sync_dma);
+
+	ep->syncbuf = NULL;
+	ep->nurbs = 0;
+	return 0;
+}
+
+/*
+ * configure a data endpoint
+ */
+static int data_ep_set_params(struct snd_usb_endpoint *ep)
+{
+	struct snd_usb_audio *chip = ep->chip;
+	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
+	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
+	unsigned int max_urbs, i;
+	const struct audioformat *fmt = ep->cur_audiofmt;
+	int frame_bits = ep->cur_frame_bytes * 8;
+	int tx_length_quirk = (has_tx_length_quirk(chip) &&
+			       usb_pipeout(ep->pipe));
+
+	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
+		      ep->ep_num, ep->pipe);
+
+	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
+		/*
+		 * When operating in DSD DOP mode, the size of a sample frame
+		 * in hardware differs from the actual physical format width
+		 * because we need to make room for the DOP markers.
+		 */
+		frame_bits += ep->cur_channels << 3;
+	}
+
+	ep->datainterval = fmt->datainterval;
+	ep->stride = frame_bits >> 3;
+
+	switch (ep->cur_format) {
+	case SNDRV_PCM_FORMAT_U8:
+		ep->silence_value = 0x80;
+		break;
+	case SNDRV_PCM_FORMAT_DSD_U8:
+	case SNDRV_PCM_FORMAT_DSD_U16_LE:
+	case SNDRV_PCM_FORMAT_DSD_U32_LE:
+	case SNDRV_PCM_FORMAT_DSD_U16_BE:
+	case SNDRV_PCM_FORMAT_DSD_U32_BE:
+		ep->silence_value = 0x69;
+		break;
+	default:
+		ep->silence_value = 0;
+	}
+
+	/* assume max. frequency is 50% higher than nominal */
+	ep->freqmax = ep->freqn + (ep->freqn >> 1);
+	/* Round up freqmax to nearest integer in order to calculate maximum
+	 * packet size, which must represent a whole number of frames.
+	 * This is accomplished by adding 0x0.ffff before converting the
+	 * Q16.16 format into integer.
+	 * In order to accurately calculate the maximum packet size when
+	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
+	 * multiply by the data interval prior to rounding. For instance,
+	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
+	 * frames with a data interval of 1, but 11 (10.25) frames with a
+	 * data interval of 2.
+	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
+	 * maximum datainterval value of 3, at USB full speed, higher for
+	 * USB high speed, noting that ep->freqmax is in units of
+	 * frames per packet in Q16.16 format.)
+	 */
+	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
+			 (frame_bits >> 3);
+	if (tx_length_quirk)
+		maxsize += sizeof(__le32); /* Space for length descriptor */
+	/* but wMaxPacketSize might reduce this */
+	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
+		/* whatever fits into a max. size packet */
+		unsigned int data_maxsize = maxsize = ep->maxpacksize;
+
+		if (tx_length_quirk)
+			/* Need to remove the length descriptor to calc freq */
+			data_maxsize -= sizeof(__le32);
+		ep->freqmax = (data_maxsize / (frame_bits >> 3))
+				<< (16 - ep->datainterval);
+	}
+
+	if (ep->fill_max) {
+		ep->curpacksize = ep->maxpacksize;
+		maxsize = ep->curpacksize;
+	} else {
+		ep->curpacksize = maxsize;
+	}
+
+	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
+		packs_per_ms = 8 >> ep->datainterval;
+		max_packs_per_urb = MAX_PACKS_HS;
+	} else {
+		packs_per_ms = 1;
+		max_packs_per_urb = MAX_PACKS;
+	}
+	if (ep->sync_source && !ep->implicit_fb_sync)
+		max_packs_per_urb = min(max_packs_per_urb,
+					1U << ep->sync_source->syncinterval);
+	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
+
+	/*
+	 * Capture endpoints need to use small URBs because there's no way
+	 * to tell in advance where the next period will end, and we don't
+	 * want the next URB to complete much after the period ends.
+	 *
+	 * Playback endpoints with implicit sync much use the same parameters
+	 * as their corresponding capture endpoint.
+	 */
+	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
+
+		/* make capture URBs <= 1 ms and smaller than a period */
+		urb_packs = min(max_packs_per_urb, packs_per_ms);
+		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
+			urb_packs >>= 1;
+		ep->nurbs = MAX_URBS;
+
+	/*
+	 * Playback endpoints without implicit sync are adjusted so that
+	 * a period fits as evenly as possible in the smallest number of
+	 * URBs.  The total number of URBs is adjusted to the size of the
+	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
+	 */
+	} else {
+		/* determine how small a packet can be */
+		minsize = (ep->freqn >> (16 - ep->datainterval)) *
+				(frame_bits >> 3);
+		/* with sync from device, assume it can be 12% lower */
+		if (ep->sync_source)
+			minsize -= minsize >> 3;
+		minsize = max(minsize, 1u);
+
+		/* how many packets will contain an entire ALSA period? */
+		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
+
+		/* how many URBs will contain a period? */
+		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
+				max_packs_per_urb);
+		/* how many packets are needed in each URB? */
+		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
+
+		/* limit the number of frames in a single URB */
+		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
+						  urbs_per_period);
+
+		/* try to use enough URBs to contain an entire ALSA buffer */
+		max_urbs = min((unsigned) MAX_URBS,
+				MAX_QUEUE * packs_per_ms / urb_packs);
+		if (chip->quirk_flags & QUIRK_FLAG_PLAYBACK_URB_FIXUP)
+			ep->nurbs = MAX_URBS;
+		else
+			ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
+	}
+
+	if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
+		urb_packs++; /* for transfer delimiter */
+	ep->max_urb_packs = urb_packs;
+
+	/* allocate and initialize data urbs */
+	for (i = 0; i < ep->nurbs; i++) {
+		struct snd_urb_ctx *u = &ep->urb[i];
+		u->index = i;
+		u->ep = ep;
+		u->packets = urb_packs;
+		u->buffer_size = maxsize * u->packets;
+		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
+		if (!u->urb)
+			goto out_of_memory;
+
+		u->urb->transfer_buffer =
+			usb_alloc_coherent(chip->dev, u->buffer_size,
+					   GFP_KERNEL, &u->urb->transfer_dma);
+		if (!u->urb->transfer_buffer)
+			goto out_of_memory;
+		u->urb->pipe = ep->pipe;
+		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+		if (chip->quirk_flags & QUIRK_FLAG_PLAYBACK_URB_FIXUP)
+			u->urb->transfer_flags |= URB_ISO_ASAP;
+		u->urb->interval = 1 << ep->datainterval;
+		u->urb->context = u;
+		u->urb->complete = snd_complete_urb;
+		INIT_LIST_HEAD(&u->ready_list);
+	}
+
+	return 0;
+
+out_of_memory:
+	release_urbs(ep, false);
+	return -ENOMEM;
+}
+
+/*
+ * configure a sync endpoint
+ */
+static int sync_ep_set_params(struct snd_usb_endpoint *ep)
+{
+	struct snd_usb_audio *chip = ep->chip;
+	int i;
+
+	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
+		      ep->ep_num, ep->pipe);
+
+	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
+					 GFP_KERNEL, &ep->sync_dma);
+	if (!ep->syncbuf)
+		return -ENOMEM;
+
+	ep->nurbs = SYNC_URBS;
+	for (i = 0; i < SYNC_URBS; i++) {
+		struct snd_urb_ctx *u = &ep->urb[i];
+		u->index = i;
+		u->ep = ep;
+		u->packets = 1;
+		u->urb = usb_alloc_urb(1, GFP_KERNEL);
+		if (!u->urb)
+			goto out_of_memory;
+		u->urb->transfer_buffer = ep->syncbuf + i * 4;
+		u->urb->transfer_dma = ep->sync_dma + i * 4;
+		u->urb->transfer_buffer_length = 4;
+		u->urb->pipe = ep->pipe;
+		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+		u->urb->number_of_packets = 1;
+		u->urb->interval = 1 << ep->syncinterval;
+		u->urb->context = u;
+		u->urb->complete = snd_complete_urb;
+	}
+
+	return 0;
+
+out_of_memory:
+	release_urbs(ep, false);
+	return -ENOMEM;
+}
+
+/* update the rate of the referred clock; return the actual rate */
+static int update_clock_ref_rate(struct snd_usb_audio *chip,
+				 struct snd_usb_endpoint *ep)
+{
+	struct snd_usb_clock_ref *clock = ep->clock_ref;
+	int rate = ep->cur_rate;
+
+	if (!clock || clock->rate == rate)
+		return rate;
+	if (clock->rate) {
+		if (atomic_read(&clock->locked))
+			return clock->rate;
+		if (clock->rate != rate) {
+			usb_audio_err(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
+				      clock->rate, rate, ep->ep_num);
+			return clock->rate;
+		}
+	}
+	clock->rate = rate;
+	clock->need_setup = true;
+	return rate;
+}
+
+/*
+ * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
+ *
+ * It's called either from hw_params callback.
+ * Determine the number of URBs to be used on this endpoint.
+ * An endpoint must be configured before it can be started.
+ * An endpoint that is already running can not be reconfigured.
+ */
+int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
+				struct snd_usb_endpoint *ep)
+{
+	const struct audioformat *fmt = ep->cur_audiofmt;
+	int err;
+
+	guard(mutex)(&chip->mutex);
+	if (!ep->need_setup)
+		return 0;
+
+	/* release old buffers, if any */
+	err = release_urbs(ep, false);
+	if (err < 0)
+		return err;
+
+	ep->datainterval = fmt->datainterval;
+	ep->maxpacksize = fmt->maxpacksize;
+	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
+
+	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
+		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
+		ep->pps = 1000 >> ep->datainterval;
+	} else {
+		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
+		ep->pps = 8000 >> ep->datainterval;
+	}
+
+	ep->sample_rem = ep->cur_rate % ep->pps;
+	ep->packsize[0] = ep->cur_rate / ep->pps;
+	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
+	if (ep->packsize[1] > ep->maxpacksize) {
+		usb_audio_dbg(chip, "Too small maxpacksize %u for rate %u / pps %u\n",
+			      ep->maxpacksize, ep->cur_rate, ep->pps);
+		return -EINVAL;
+	}
+
+	/* calculate the frequency in 16.16 format */
+	ep->freqm = ep->freqn;
+	ep->freqshift = INT_MIN;
+
+	ep->phase = 0;
+
+	switch (ep->type) {
+	case  SND_USB_ENDPOINT_TYPE_DATA:
+		err = data_ep_set_params(ep);
+		break;
+	case  SND_USB_ENDPOINT_TYPE_SYNC:
+		err = sync_ep_set_params(ep);
+		break;
+	default:
+		err = -EINVAL;
+	}
+
+	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
+
+	if (err < 0)
+		return err;
+
+	/* some unit conversions in runtime */
+	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
+	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
+
+	ep->packsize[0] = min(ep->packsize[0], ep->maxframesize);
+	ep->packsize[1] = min(ep->packsize[1], ep->maxframesize);
+
+	err = update_clock_ref_rate(chip, ep);
+	if (err >= 0) {
+		ep->need_setup = false;
+		err = 0;
+	}
+
+	return err;
+}
+
+static int init_sample_rate(struct snd_usb_audio *chip,
+			    struct snd_usb_endpoint *ep)
+{
+	struct snd_usb_clock_ref *clock = ep->clock_ref;
+	int rate, err;
+
+	rate = update_clock_ref_rate(chip, ep);
+	if (rate < 0)
+		return rate;
+	if (clock && !clock->need_setup)
+		return 0;
+
+	if (!ep->fixed_rate) {
+		err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate);
+		if (err < 0) {
+			if (clock)
+				clock->rate = 0; /* reset rate */
+			return err;
+		}
+	}
+
+	if (clock)
+		clock->need_setup = false;
+	return 0;
+}
+
+/*
+ * snd_usb_endpoint_prepare: Prepare the endpoint
+ *
+ * This function sets up the EP to be fully usable state.
+ * It's called either from prepare callback.
+ * The function checks need_setup flag, and performs nothing unless needed,
+ * so it's safe to call this multiple times.
+ *
+ * This returns zero if unchanged, 1 if the configuration has changed,
+ * or a negative error code.
+ */
+int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
+			     struct snd_usb_endpoint *ep)
+{
+	bool iface_first;
+	int err = 0;
+
+	guard(mutex)(&chip->mutex);
+	if (WARN_ON(!ep->iface_ref))
+		return 0;
+	if (!ep->need_prepare)
+		return 0;
+
+	/* If the interface has been already set up, just set EP parameters */
+	if (!ep->iface_ref->need_setup) {
+		/* sample rate setup of UAC1 is per endpoint, and we need
+		 * to update at each EP configuration
+		 */
+		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
+			err = init_sample_rate(chip, ep);
+			if (err < 0)
+				return err;
+		}
+		goto done;
+	}
+
+	/* Need to deselect altsetting at first */
+	endpoint_set_interface(chip, ep, false);
+
+	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
+	 * to be set up before parameter setups
+	 */
+	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
+	/* Workaround for devices that require the interface setup at first like UAC1 */
+	if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
+		iface_first = true;
+	if (iface_first) {
+		err = endpoint_set_interface(chip, ep, true);
+		if (err < 0)
+			return err;
+	}
+
+	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
+	if (err < 0)
+		return err;
+
+	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
+	if (err < 0)
+		return err;
+
+	err = init_sample_rate(chip, ep);
+	if (err < 0)
+		return err;
+
+	/* for UAC2/3, enable the interface altset here at last */
+	if (!iface_first) {
+		err = endpoint_set_interface(chip, ep, true);
+		if (err < 0)
+			return err;
+	}
+
+	ep->iface_ref->need_setup = false;
+
+ done:
+	ep->need_prepare = false;
+	return 1;
+}
+EXPORT_SYMBOL_GPL(snd_usb_endpoint_prepare);
+
+/* get the current rate set to the given clock by any endpoint */
+int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
+{
+	struct snd_usb_clock_ref *ref;
+	int rate = 0;
+
+	if (!clock)
+		return 0;
+	guard(mutex)(&chip->mutex);
+	list_for_each_entry(ref, &chip->clock_ref_list, list) {
+		if (ref->clock == clock) {
+			rate = ref->rate;
+			break;
+		}
+	}
+	return rate;
+}
+
+/**
+ * snd_usb_endpoint_start: start an snd_usb_endpoint
+ *
+ * @ep: the endpoint to start
+ *
+ * A call to this function will increment the running count of the endpoint.
+ * In case it is not already running, the URBs for this endpoint will be
+ * submitted. Otherwise, this function does nothing.
+ *
+ * Must be balanced to calls of snd_usb_endpoint_stop().
+ *
+ * Returns an error if the URB submission failed, 0 in all other cases.
+ */
+int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
+{
+	bool is_playback = usb_pipeout(ep->pipe);
+	int err;
+	unsigned int i;
+
+	if (atomic_read(&ep->chip->shutdown))
+		return -EBADFD;
+
+	if (ep->sync_source)
+		WRITE_ONCE(ep->sync_source->sync_sink, ep);
+
+	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
+		      ep_type_name(ep->type), ep->ep_num,
+		      atomic_read(&ep->running));
+
+	/* already running? */
+	if (atomic_inc_return(&ep->running) != 1)
+		return 0;
+
+	if (ep->clock_ref)
+		atomic_inc(&ep->clock_ref->locked);
+
+	ep->active_mask = 0;
+	ep->unlink_mask = 0;
+	ep->phase = 0;
+	ep->sample_accum = 0;
+
+	snd_usb_endpoint_start_quirk(ep);
+
+	/*
+	 * If this endpoint has a data endpoint as implicit feedback source,
+	 * don't start the urbs here. Instead, mark them all as available,
+	 * wait for the record urbs to return and queue the playback urbs
+	 * from that context.
+	 */
+
+	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
+		goto __error;
+
+	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
+	    !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
+		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
+		i = 0;
+		goto fill_rest;
+	}
+
+	for (i = 0; i < ep->nurbs; i++) {
+		struct urb *urb = ep->urb[i].urb;
+
+		if (snd_BUG_ON(!urb))
+			goto __error;
+
+		if (is_playback)
+			err = prepare_outbound_urb(ep, urb->context, true);
+		else
+			err = prepare_inbound_urb(ep, urb->context);
+		if (err < 0) {
+			/* stop filling at applptr */
+			if (err == -EAGAIN)
+				break;
+			usb_audio_dbg(ep->chip,
+				      "EP 0x%x: failed to prepare urb: %d\n",
+				      ep->ep_num, err);
+			goto __error;
+		}
+
+		if (!atomic_read(&ep->chip->shutdown))
+			err = usb_submit_urb(urb, GFP_ATOMIC);
+		else
+			err = -ENODEV;
+		if (err < 0) {
+			if (!atomic_read(&ep->chip->shutdown))
+				usb_audio_err(ep->chip,
+					      "cannot submit urb %d, error %d: %s\n",
+					      i, err, usb_error_string(err));
+			goto __error;
+		}
+		set_bit(i, &ep->active_mask);
+		atomic_inc(&ep->submitted_urbs);
+	}
+
+	if (!i) {
+		usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
+			      ep->ep_num);
+		goto __error;
+	}
+
+	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
+		      i, ep->ep_num);
+
+ fill_rest:
+	/* put the remaining URBs to ready list */
+	if (is_playback) {
+		for (; i < ep->nurbs; i++)
+			push_back_to_ready_list(ep, ep->urb + i);
+	}
+
+	return 0;
+
+__error:
+	snd_usb_endpoint_stop(ep, false);
+	return -EPIPE;
+}
+
+/**
+ * snd_usb_endpoint_stop: stop an snd_usb_endpoint
+ *
+ * @ep: the endpoint to stop (may be NULL)
+ * @keep_pending: keep in-flight URBs
+ *
+ * A call to this function will decrement the running count of the endpoint.
+ * In case the last user has requested the endpoint stop, the URBs will
+ * actually be deactivated.
+ *
+ * Must be balanced to calls of snd_usb_endpoint_start().
+ *
+ * The caller needs to synchronize the pending stop operation via
+ * snd_usb_endpoint_sync_pending_stop().
+ */
+void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
+{
+	if (!ep)
+		return;
+
+	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
+		      ep_type_name(ep->type), ep->ep_num,
+		      atomic_read(&ep->running));
+
+	if (snd_BUG_ON(!atomic_read(&ep->running)))
+		return;
+
+	if (!atomic_dec_return(&ep->running)) {
+		if (ep->sync_source)
+			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
+		stop_urbs(ep, false, keep_pending);
+		if (ep->clock_ref)
+			atomic_dec(&ep->clock_ref->locked);
+
+		if (ep->chip->quirk_flags & QUIRK_FLAG_FORCE_IFACE_RESET &&
+		    usb_pipeout(ep->pipe)) {
+			ep->need_prepare = true;
+			if (ep->iface_ref)
+				ep->iface_ref->need_setup = true;
+		}
+	}
+}
+
+/**
+ * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
+ *
+ * @ep: the endpoint to release
+ *
+ * This function does not care for the endpoint's running count but will tear
+ * down all the streaming URBs immediately.
+ */
+void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
+{
+	release_urbs(ep, true);
+}
+
+/**
+ * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
+ * @chip: The chip
+ *
+ * This free all endpoints and those resources
+ */
+void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
+{
+	struct snd_usb_endpoint *ep, *en;
+	struct snd_usb_iface_ref *ip, *in;
+	struct snd_usb_clock_ref *cp, *cn;
+
+	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
+		kfree(ep);
+
+	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
+		kfree(ip);
+
+	list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
+		kfree(cp);
+}
+
+/*
+ * snd_usb_handle_sync_urb: parse an USB sync packet
+ *
+ * @ep: the endpoint to handle the packet
+ * @sender: the sending endpoint
+ * @urb: the received packet
+ *
+ * This function is called from the context of an endpoint that received
+ * the packet and is used to let another endpoint object handle the payload.
+ */
+static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
+				    struct snd_usb_endpoint *sender,
+				    const struct urb *urb)
+{
+	int shift;
+	unsigned int f;
+	unsigned long flags;
+
+	snd_BUG_ON(ep == sender);
+
+	/*
+	 * In case the endpoint is operating in implicit feedback mode, prepare
+	 * a new outbound URB that has the same layout as the received packet
+	 * and add it to the list of pending urbs. queue_pending_output_urbs()
+	 * will take care of them later.
+	 */
+	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
+	    atomic_read(&ep->running)) {
+
+		/* implicit feedback case */
+		int i, bytes = 0;
+		struct snd_urb_ctx *in_ctx;
+		struct snd_usb_packet_info *out_packet;
+
+		in_ctx = urb->context;
+
+		/* Count overall packet size */
+		for (i = 0; i < in_ctx->packets; i++)
+			if (urb->iso_frame_desc[i].status == 0)
+				bytes += urb->iso_frame_desc[i].actual_length;
+
+		/*
+		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
+		 * streaming once it received a 0-byte OUT URB
+		 *
+		 * However, on devices where bytes==0 means every sync-source
+		 * packet errored (e.g. Behringer Flow 8 returning -EXDEV bursts
+		 * for entire capture URBs), an unconditional return starves the
+		 * IFB-fed OUT ring permanently. Such devices set
+		 * QUIRK_FLAG_IFB_SILENCE_ON_EMPTY to fall through and enqueue a
+		 * packet_info with size 0 packets, so playback emits silence
+		 * and the OUT ring keeps moving.
+		 */
+		if (bytes == 0 && !(ep->chip->quirk_flags & QUIRK_FLAG_IFB_SILENCE_ON_EMPTY))
+			return;
+
+		spin_lock_irqsave(&ep->lock, flags);
+		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
+			spin_unlock_irqrestore(&ep->lock, flags);
+			if (notify_xrun(ep)) {
+				usb_audio_err(ep->chip,
+					      "next packet FIFO overflow EP 0x%x\n",
+					      ep->ep_num);
+			}
+			return;
+		}
+
+		out_packet = next_packet_fifo_enqueue(ep);
+
+		/*
+		 * Iterate through the inbound packet and prepare the lengths
+		 * for the output packet. The OUT packet we are about to send
+		 * will have the same amount of payload bytes per stride as the
+		 * IN packet we just received. Since the actual size is scaled
+		 * by the stride, use the sender stride to calculate the length
+		 * in case the number of channels differ between the implicitly
+		 * fed-back endpoint and the synchronizing endpoint.
+		 */
+
+		out_packet->packets = in_ctx->packets;
+		for (i = 0; i < in_ctx->packets; i++) {
+			if (urb->iso_frame_desc[i].status == 0) {
+				unsigned int frames =
+					urb->iso_frame_desc[i].actual_length / sender->stride;
+				out_packet->packet_size[i] = min(frames, ep->maxframesize);
+			} else {
+				out_packet->packet_size[i] = 0;
+			}
+		}
+
+		spin_unlock_irqrestore(&ep->lock, flags);
+		snd_usb_queue_pending_output_urbs(ep, false);
+
+		return;
+	}
+
+	/*
+	 * process after playback sync complete
+	 *
+	 * Full speed devices report feedback values in 10.14 format as samples
+	 * per frame, high speed devices in 16.16 format as samples per
+	 * microframe.
+	 *
+	 * Because the Audio Class 1 spec was written before USB 2.0, many high
+	 * speed devices use a wrong interpretation, some others use an
+	 * entirely different format.
+	 *
+	 * Therefore, we cannot predict what format any particular device uses
+	 * and must detect it automatically.
+	 */
+
+	if (urb->iso_frame_desc[0].status != 0 ||
+	    urb->iso_frame_desc[0].actual_length < 3)
+		return;
+
+	f = le32_to_cpup(urb->transfer_buffer);
+	if (urb->iso_frame_desc[0].actual_length == 3)
+		f &= 0x00ffffff;
+	else
+		f &= 0x0fffffff;
+
+	if (f == 0)
+		return;
+
+	if (unlikely(sender->tenor_fb_quirk)) {
+		/*
+		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
+		 * and others) sometimes change the feedback value
+		 * by +/- 0x1.0000.
+		 */
+		if (f < ep->freqn - 0x8000)
+			f += 0xf000;
+		else if (f > ep->freqn + 0x8000)
+			f -= 0xf000;
+	} else if (unlikely(ep->freqshift == INT_MIN)) {
+		/*
+		 * The first time we see a feedback value, determine its format
+		 * by shifting it left or right until it matches the nominal
+		 * frequency value.  This assumes that the feedback does not
+		 * differ from the nominal value more than +50% or -25%.
+		 */
+		shift = 0;
+		while (f < ep->freqn - ep->freqn / 4) {
+			f <<= 1;
+			shift++;
+		}
+		while (f > ep->freqn + ep->freqn / 2) {
+			f >>= 1;
+			shift--;
+		}
+		ep->freqshift = shift;
+	} else if (ep->freqshift >= 0)
+		f <<= ep->freqshift;
+	else
+		f >>= -ep->freqshift;
+
+	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
+		/*
+		 * If the frequency looks valid, set it.
+		 * This value is referred to in prepare_playback_urb().
+		 */
+		guard(spinlock_irqsave)(&ep->lock);
+		ep->freqm = f;
+	} else {
+		/*
+		 * Out of range; maybe the shift value is wrong.
+		 * Reset it so that we autodetect again the next time.
+		 */
+		ep->freqshift = INT_MIN;
+	}
+}
+
diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h
new file mode 100644
index 000000000..ba70f52f6
--- /dev/null
+++ b/sound/usb/endpoint.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_ENDPOINT_H
+#define __USBAUDIO_ENDPOINT_H
+
+#define SND_USB_ENDPOINT_TYPE_DATA     0
+#define SND_USB_ENDPOINT_TYPE_SYNC     1
+
+struct snd_usb_endpoint *snd_usb_get_endpoint(struct snd_usb_audio *chip,
+					      int ep_num);
+
+int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type);
+
+struct snd_usb_endpoint *
+snd_usb_endpoint_open(struct snd_usb_audio *chip,
+		      const struct audioformat *fp,
+		      const struct snd_pcm_hw_params *params,
+		      bool is_sync_ep,
+		      bool fixed_rate);
+void snd_usb_endpoint_close(struct snd_usb_audio *chip,
+			    struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
+				struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
+			     struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock);
+
+bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
+				 struct snd_usb_endpoint *ep,
+				 const struct audioformat *fp,
+				 const struct snd_pcm_hw_params *params);
+
+void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
+			       struct snd_usb_endpoint *data_ep,
+			       struct snd_usb_endpoint *sync_ep);
+void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
+				   int (*prepare)(struct snd_usb_substream *subs,
+						  struct urb *urb,
+						  bool in_stream_lock),
+				   void (*retire)(struct snd_usb_substream *subs,
+						  struct urb *urb),
+				   struct snd_usb_substream *data_subs);
+
+int snd_usb_endpoint_start(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending);
+void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_release(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_free_all(struct snd_usb_audio *chip);
+
+int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
+				      struct snd_urb_ctx *ctx, int idx,
+				      unsigned int avail);
+int snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
+				      bool in_stream_lock);
+
+#endif /* __USBAUDIO_ENDPOINT_H */
diff --git a/sound/usb/fcp.c b/sound/usb/fcp.c
new file mode 100644
index 000000000..68bb7eabf
--- /dev/null
+++ b/sound/usb/fcp.c
@@ -0,0 +1,1151 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Focusrite Control Protocol Driver for ALSA
+ *
+ * Copyright (c) 2024-2025 by Geoffrey D. Bennett <g at b4.vu>
+ */
+/*
+ * DOC: Theory of Operation
+ *
+ * The Focusrite Control Protocol (FCP) driver provides a minimal
+ * kernel interface that allows a user-space driver (primarily
+ * fcp-server) to communicate with Focusrite USB audio interfaces
+ * using their vendor-specific protocol. This protocol is used by
+ * Scarlett 2nd Gen, 3rd Gen, 4th Gen, Clarett USB, Clarett+, and
+ * Vocaster series devices.
+ *
+ * Unlike the existing scarlett2 driver which implements all controls
+ * in kernel space, this driver takes a lighter-weight approach by
+ * moving most functionality to user space. The only control
+ * implemented in kernel space is the Level Meter, since it requires
+ * frequent polling of volatile data.
+ *
+ * The driver provides an hwdep interface that allows the user-space
+ * driver to:
+ *  - Initialise the protocol
+ *  - Send arbitrary FCP commands to the device
+ *  - Receive notifications from the device
+ *  - Configure the Level Meter control
+ *
+ * Usage Flow
+ * ----------
+ * 1. Open the hwdep device (requires CAP_SYS_RAWIO)
+ * 2. Get protocol version using FCP_IOCTL_PVERSION
+ * 3. Initialise protocol using FCP_IOCTL_INIT
+ * 4. Send commands using FCP_IOCTL_CMD
+ * 5. Receive notifications using read()
+ * 6. Optionally set up the Level Meter control using
+ *    FCP_IOCTL_SET_METER_MAP
+ * 7. Optionally add labels to the Level Meter control using
+ *    FCP_IOCTL_SET_METER_LABELS
+ *
+ * Level Meter
+ * -----------
+ * The Level Meter is implemented as an ALSA control that provides
+ * real-time level monitoring. When the control is read, the driver
+ * requests the current meter levels from the device, translates the
+ * levels using the configured mapping, and returns the result to the
+ * user. The mapping between device meters and the ALSA control's
+ * channels is configured with FCP_IOCTL_SET_METER_MAP.
+ *
+ * Labels for the Level Meter channels can be set using
+ * FCP_IOCTL_SET_METER_LABELS and read by applications through the
+ * control's TLV data. The labels are transferred as a sequence of
+ * null-terminated strings.
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#include <sound/control.h>
+#include <sound/hwdep.h>
+#include <sound/tlv.h>
+
+#include <uapi/sound/fcp.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "helper.h"
+
+#include "fcp.h"
+
+/* notify waiting to send to *file */
+struct fcp_notify {
+	wait_queue_head_t queue;
+	u32               event;
+	spinlock_t        lock;
+};
+
+struct fcp_data {
+	struct usb_mixer_interface *mixer;
+
+	struct mutex mutex;         /* serialise access to the device */
+	struct completion cmd_done; /* wait for command completion */
+	struct file *file;          /* hwdep file */
+	struct urb *urb;            /* FCP notification endpoint */
+
+	struct fcp_notify notify;
+
+	u8  bInterfaceNumber;
+	u8  bEndpointAddress;
+	u16 wMaxPacketSize;
+	u8  bInterval;
+
+	uint16_t step0_resp_size;
+	uint16_t step2_resp_size;
+	uint32_t init1_opcode;
+	uint32_t init2_opcode;
+
+	u8  init;
+	u16 seq;
+
+	u8                   num_meter_slots;
+	s16                 *meter_level_map;
+	__le32              *meter_levels;
+	struct snd_kcontrol *meter_ctl;
+
+	unsigned int *meter_labels_tlv;
+	int           meter_labels_tlv_size;
+};
+
+/*** USB Interactions ***/
+
+/* FCP Command ACK notification bit */
+#define FCP_NOTIFY_ACK 1
+
+/* Vendor-specific USB control requests */
+#define FCP_USB_REQ_STEP0  0
+#define FCP_USB_REQ_CMD_TX 2
+#define FCP_USB_REQ_CMD_RX 3
+
+/* Focusrite Control Protocol opcodes that the kernel side needs to
+ * know about
+ */
+#define FCP_USB_REBOOT      0x00000003
+#define FCP_USB_GET_METER   0x00001001
+#define FCP_USB_FLASH_ERASE 0x00004002
+#define FCP_USB_FLASH_WRITE 0x00004004
+
+#define FCP_USB_METER_LEVELS_GET_MAGIC 1
+
+#define FCP_SEGMENT_APP_GOLD 0
+
+#define FCP_MAX_METER_MAP_SIZE \
+	(sizeof_field(struct snd_ctl_elem_value, value.integer.value) / \
+	 sizeof(long))
+
+/* Forward declarations */
+static int fcp_init(struct usb_mixer_interface *mixer,
+		    void *step0_resp, void *step2_resp);
+
+/* FCP command request/response format */
+struct fcp_usb_packet {
+	__le32 opcode;
+	__le16 size;
+	__le16 seq;
+	__le32 error;
+	__le32 pad;
+	u8 data[];
+};
+
+static void fcp_fill_request_header(struct fcp_data *private,
+				    struct fcp_usb_packet *req,
+				    u32 opcode, u16 req_size)
+{
+	/* sequence must go up by 1 for each request */
+	u16 seq = private->seq++;
+
+	req->opcode = cpu_to_le32(opcode);
+	req->size = cpu_to_le16(req_size);
+	req->seq = cpu_to_le16(seq);
+	req->error = 0;
+	req->pad = 0;
+}
+
+static int fcp_usb_tx(struct usb_device *dev, int interface,
+		      void *buf, u16 size)
+{
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			FCP_USB_REQ_CMD_TX,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			0, interface, buf, size);
+}
+
+static int fcp_usb_rx(struct usb_device *dev, int interface,
+		      void *buf, u16 size)
+{
+	return snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			FCP_USB_REQ_CMD_RX,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			0, interface, buf, size);
+}
+
+/* Send an FCP command and get the response */
+static int fcp_usb(struct usb_mixer_interface *mixer, u32 opcode,
+		   const void *req_data, u16 req_size,
+		   void *resp_data, u16 resp_size)
+{
+	struct fcp_data *private = mixer->private_data;
+	struct usb_device *dev = mixer->chip->dev;
+	int retries = 0;
+	const int max_retries = 5;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(mixer->chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	if (!private->urb)
+		return -ENODEV;
+
+	struct fcp_usb_packet *req __free(kfree) = NULL;
+	size_t req_buf_size = struct_size(req, data, req_size);
+	req = kmalloc_flex(*req, data, req_size);
+	if (!req)
+		return -ENOMEM;
+
+	struct fcp_usb_packet *resp __free(kfree) = NULL;
+	size_t resp_buf_size = struct_size(resp, data, resp_size);
+	resp = kmalloc_flex(*resp, data, resp_size);
+	if (!resp)
+		return -ENOMEM;
+
+	/* build request message */
+	fcp_fill_request_header(private, req, opcode, req_size);
+	if (req_size)
+		memcpy(req->data, req_data, req_size);
+
+	/* send the request and retry on EPROTO */
+retry:
+	err = fcp_usb_tx(dev, private->bInterfaceNumber, req, req_buf_size);
+	if (err == -EPROTO && ++retries <= max_retries) {
+		msleep(1 << (retries - 1));
+		goto retry;
+	}
+
+	if (err != req_buf_size) {
+		usb_audio_err(mixer->chip,
+			      "FCP request %08x failed: %d\n", opcode, err);
+		return -EINVAL;
+	}
+
+	if (!wait_for_completion_timeout(&private->cmd_done,
+					 msecs_to_jiffies(1000))) {
+		usb_audio_err(mixer->chip,
+			      "FCP request %08x timed out\n", opcode);
+
+		return -ETIMEDOUT;
+	}
+
+	/* send a second message to get the response */
+	err = fcp_usb_rx(dev, private->bInterfaceNumber, resp, resp_buf_size);
+
+	/* validate the response */
+
+	if (err < 0) {
+
+		/* ESHUTDOWN and EPROTO are valid responses to a
+		 * reboot request
+		 */
+		if (opcode == FCP_USB_REBOOT &&
+		    (err == -ESHUTDOWN || err == -EPROTO))
+			return 0;
+
+		usb_audio_err(mixer->chip,
+			      "FCP read response %08x failed: %d\n",
+			      opcode, err);
+		return -EINVAL;
+	}
+
+	if (err < sizeof(*resp)) {
+		usb_audio_err(mixer->chip,
+			      "FCP response %08x too short: %d\n",
+			      opcode, err);
+		return -EINVAL;
+	}
+
+	if (req->seq != resp->seq) {
+		usb_audio_err(mixer->chip,
+			      "FCP response %08x seq mismatch %d/%d\n",
+			      opcode,
+			      le16_to_cpu(req->seq), le16_to_cpu(resp->seq));
+		return -EINVAL;
+	}
+
+	if (req->opcode != resp->opcode) {
+		usb_audio_err(mixer->chip,
+			      "FCP response %08x opcode mismatch %08x\n",
+			      opcode, le32_to_cpu(resp->opcode));
+		return -EINVAL;
+	}
+
+	if (resp->error) {
+		usb_audio_err(mixer->chip,
+			      "FCP response %08x error %d\n",
+			      opcode, le32_to_cpu(resp->error));
+		return -EINVAL;
+	}
+
+	if (err != resp_buf_size) {
+		usb_audio_err(mixer->chip,
+			      "FCP response %08x buffer size mismatch %d/%zu\n",
+			      opcode, err, resp_buf_size);
+		return -EINVAL;
+	}
+
+	if (resp_size != le16_to_cpu(resp->size)) {
+		usb_audio_err(mixer->chip,
+			      "FCP response %08x size mismatch %d/%d\n",
+			      opcode, resp_size, le16_to_cpu(resp->size));
+		return -EINVAL;
+	}
+
+	if (resp_data && resp_size > 0)
+		memcpy(resp_data, resp->data, resp_size);
+
+	return 0;
+}
+
+static int fcp_reinit(struct usb_mixer_interface *mixer)
+{
+	struct fcp_data *private = mixer->private_data;
+
+	if (private->urb)
+		return 0;
+
+	void *step0_resp __free(kfree) =
+		kmalloc(private->step0_resp_size, GFP_KERNEL);
+	if (!step0_resp)
+		return -ENOMEM;
+
+	void *step2_resp __free(kfree) =
+		kmalloc(private->step2_resp_size, GFP_KERNEL);
+	if (!step2_resp)
+		return -ENOMEM;
+
+	return fcp_init(mixer, step0_resp, step2_resp);
+}
+
+/*** Control Functions ***/
+
+/* helper function to create a new control */
+static int fcp_add_new_ctl(struct usb_mixer_interface *mixer,
+			   const struct snd_kcontrol_new *ncontrol,
+			   int index, int channels, const char *name,
+			   struct snd_kcontrol **kctl_return)
+{
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *elem;
+	int err;
+
+	elem = kzalloc_obj(*elem);
+	if (!elem)
+		return -ENOMEM;
+
+	/* We set USB_MIXER_BESPOKEN type, so that the core USB mixer code
+	 * ignores them for resume and other operations.
+	 * Also, the head.id field is set to 0, as we don't use this field.
+	 */
+	elem->head.mixer = mixer;
+	elem->control = index;
+	elem->head.id = 0;
+	elem->channels = channels;
+	elem->val_type = USB_MIXER_BESPOKEN;
+
+	kctl = snd_ctl_new1(ncontrol, elem);
+	if (!kctl) {
+		kfree(elem);
+		return -ENOMEM;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	strscpy(kctl->id.name, name, sizeof(kctl->id.name));
+
+	err = snd_usb_mixer_add_control(&elem->head, kctl);
+	if (err < 0)
+		return err;
+
+	if (kctl_return)
+		*kctl_return = kctl;
+
+	return 0;
+}
+
+/*** Level Meter Control ***/
+
+static int fcp_meter_ctl_info(struct snd_kcontrol *kctl,
+			      struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 4095;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static int fcp_meter_ctl_get(struct snd_kcontrol *kctl,
+			     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct fcp_data *private = mixer->private_data;
+	int num_meter_slots, resp_size;
+	__le32 *resp = private->meter_levels;
+	int i, err = 0;
+
+	struct {
+		__le16 pad;
+		__le16 num_meters;
+		__le32 magic;
+	} __packed req;
+
+	guard(mutex)(&private->mutex);
+
+	err = fcp_reinit(mixer);
+	if (err < 0)
+		return err;
+
+	num_meter_slots = private->num_meter_slots;
+	resp_size = num_meter_slots * sizeof(u32);
+
+	req.pad = 0;
+	req.num_meters = cpu_to_le16(num_meter_slots);
+	req.magic = cpu_to_le32(FCP_USB_METER_LEVELS_GET_MAGIC);
+	err = fcp_usb(mixer, FCP_USB_GET_METER,
+		      &req, sizeof(req), resp, resp_size);
+	if (err < 0)
+		return err;
+
+	if (WARN_ON_ONCE(elem->channels > FCP_MAX_METER_MAP_SIZE))
+		return -EINVAL;
+
+	/* copy & translate from resp[] using meter_level_map[] */
+	for (i = 0; i < elem->channels; i++) {
+		int idx = private->meter_level_map[i];
+		int value = idx < 0 ? 0 : le32_to_cpu(resp[idx]);
+
+		ucontrol->value.integer.value[i] = value;
+	}
+
+	return 0;
+}
+
+static int fcp_meter_tlv_callback(struct snd_kcontrol *kctl,
+				  int op_flag, unsigned int size,
+				  unsigned int __user *tlv)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct fcp_data *private = mixer->private_data;
+
+	guard(mutex)(&private->mutex);
+
+	if (op_flag == SNDRV_CTL_TLV_OP_READ) {
+		if (private->meter_labels_tlv_size == 0)
+			return 0;
+
+		if (size > private->meter_labels_tlv_size)
+			size = private->meter_labels_tlv_size;
+
+		if (copy_to_user(tlv, private->meter_labels_tlv, size))
+			return -EFAULT;
+
+		return size;
+	}
+
+	return -EINVAL;
+}
+
+static const struct snd_kcontrol_new fcp_meter_ctl = {
+	.iface  = SNDRV_CTL_ELEM_IFACE_PCM,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ |
+		  SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+	.info = fcp_meter_ctl_info,
+	.get  = fcp_meter_ctl_get,
+	.tlv  = { .c = fcp_meter_tlv_callback },
+};
+
+/*** hwdep interface ***/
+
+/* FCP initialisation */
+static int fcp_ioctl_init(struct usb_mixer_interface *mixer,
+			  struct fcp_init __user *arg)
+{
+	struct fcp_init init;
+	struct usb_device *dev = mixer->chip->dev;
+	struct fcp_data *private = mixer->private_data;
+	void *step2_resp;
+	int err, buf_size;
+
+	if (usb_pipe_type_check(dev, usb_sndctrlpipe(dev, 0)))
+		return -EINVAL;
+
+	/* Get initialisation parameters */
+	if (copy_from_user(&init, arg, sizeof(init)))
+		return -EFAULT;
+
+	/* Validate the response sizes */
+	if (init.step0_resp_size < 1 ||
+	    init.step0_resp_size > 255 ||
+	    init.step2_resp_size < 1 ||
+	    init.step2_resp_size > 255)
+		return -EINVAL;
+
+	/* Allocate response buffer */
+	buf_size = init.step0_resp_size + init.step2_resp_size;
+
+	void *resp __free(kfree) =
+		kzalloc(buf_size, GFP_KERNEL);
+	if (!resp)
+		return -ENOMEM;
+
+	private->step0_resp_size = init.step0_resp_size;
+	private->step2_resp_size = init.step2_resp_size;
+	private->init1_opcode = init.init1_opcode;
+	private->init2_opcode = init.init2_opcode;
+
+	step2_resp = resp + private->step0_resp_size;
+
+	err = fcp_init(mixer, resp, step2_resp);
+	if (err < 0)
+		return err;
+
+	if (copy_to_user(arg->resp, resp, buf_size))
+		return -EFAULT;
+
+	return 0;
+}
+
+/* Check that the command is allowed
+ * Don't permit erasing/writing segment 0 (App_Gold)
+ */
+static int fcp_validate_cmd(u32 opcode, void *data, u16 size)
+{
+	if (opcode == FCP_USB_FLASH_ERASE) {
+		struct {
+			__le32 segment_num;
+			__le32 pad;
+		} __packed *req = data;
+
+		if (size != sizeof(*req))
+			return -EINVAL;
+
+		if (le32_to_cpu(req->segment_num) == FCP_SEGMENT_APP_GOLD)
+			return -EPERM;
+
+		if (req->pad != 0)
+			return -EINVAL;
+
+	} else if (opcode == FCP_USB_FLASH_WRITE) {
+		struct {
+			__le32 segment_num;
+			__le32 offset;
+			__le32 pad;
+			u8 data[];
+		} __packed *req = data;
+
+		if (size < sizeof(*req))
+			return -EINVAL;
+
+		if (le32_to_cpu(req->segment_num) == FCP_SEGMENT_APP_GOLD)
+			return -EPERM;
+
+		if (req->pad != 0)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Execute an FCP command specified by the user */
+static int fcp_ioctl_cmd(struct usb_mixer_interface *mixer,
+			 struct fcp_cmd __user *arg)
+{
+	struct fcp_cmd cmd;
+	int err, buf_size;
+	void *data __free(kfree) = NULL;
+
+	/* get opcode and request/response size */
+	if (copy_from_user(&cmd, arg, sizeof(cmd)))
+		return -EFAULT;
+
+	/* validate request and response sizes */
+	if (cmd.req_size > 4096 || cmd.resp_size > 4096)
+		return -EINVAL;
+
+	/* reinit if needed */
+	err = fcp_reinit(mixer);
+	if (err < 0)
+		return err;
+
+	/* allocate request/response buffer */
+	buf_size = max(cmd.req_size, cmd.resp_size);
+
+	if (buf_size > 0) {
+		data = kmalloc(buf_size, GFP_KERNEL);
+		if (!data)
+			return -ENOMEM;
+	}
+
+	/* copy request from user */
+	if (cmd.req_size > 0)
+		if (copy_from_user(data, arg->data, cmd.req_size))
+			return -EFAULT;
+
+	/* check that the command is allowed */
+	err = fcp_validate_cmd(cmd.opcode, data, cmd.req_size);
+	if (err < 0)
+		return err;
+
+	/* send request, get response */
+	err = fcp_usb(mixer, cmd.opcode,
+		      data, cmd.req_size, data, cmd.resp_size);
+	if (err < 0)
+		return err;
+
+	/* copy response to user */
+	if (cmd.resp_size > 0)
+		if (copy_to_user(arg->data, data, cmd.resp_size))
+			return -EFAULT;
+
+	return 0;
+}
+
+/* Validate the Level Meter map passed by the user */
+static int validate_meter_map(const s16 *map, int map_size, int meter_slots)
+{
+	int i;
+
+	for (i = 0; i < map_size; i++)
+		if (map[i] < -1 || map[i] >= meter_slots)
+			return -EINVAL;
+
+	return 0;
+}
+
+/* Set the Level Meter map and add the control */
+static int fcp_ioctl_set_meter_map(struct usb_mixer_interface *mixer,
+				   struct fcp_meter_map __user *arg)
+{
+	struct fcp_meter_map map;
+	struct fcp_data *private = mixer->private_data;
+	int err;
+
+	if (copy_from_user(&map, arg, sizeof(map)))
+		return -EFAULT;
+
+	/* Don't allow changing the map size or meter slots once set */
+	if (private->meter_ctl) {
+		struct usb_mixer_elem_info *elem =
+			private->meter_ctl->private_data;
+
+		if (map.map_size != elem->channels ||
+		    map.meter_slots != private->num_meter_slots)
+			return -EINVAL;
+	}
+
+	/* Validate the map size */
+	if (map.map_size < 1 ||
+	    map.map_size > FCP_MAX_METER_MAP_SIZE ||
+	    map.meter_slots < 1 || map.meter_slots > 255)
+		return -EINVAL;
+
+	/* Allocate and copy the map data */
+	s16 *tmp_map __free(kfree) =
+		memdup_array_user(arg->map, map.map_size, sizeof(s16));
+	if (IS_ERR(tmp_map))
+		return PTR_ERR(tmp_map);
+
+	err = validate_meter_map(tmp_map, map.map_size, map.meter_slots);
+	if (err < 0)
+		return err;
+
+	/* If the control doesn't exist, create it */
+	if (!private->meter_ctl) {
+		/* Allocate buffer for the map */
+		s16 *new_map __free(kfree) =
+			kmalloc_objs(s16, map.map_size);
+		if (!new_map)
+			return -ENOMEM;
+
+		/* Allocate buffer for reading meter levels */
+		__le32 *meter_levels __free(kfree) =
+			kmalloc_array(map.meter_slots, sizeof(__le32),
+				      GFP_KERNEL);
+		if (!meter_levels)
+			return -ENOMEM;
+
+		/* Create the Level Meter control */
+		err = fcp_add_new_ctl(mixer, &fcp_meter_ctl, 0, map.map_size,
+				      "Level Meter", &private->meter_ctl);
+		if (err < 0)
+			return err;
+
+		/* Success; save the pointers in private and don't free them */
+		private->meter_level_map = new_map;
+		private->meter_levels = meter_levels;
+		private->num_meter_slots = map.meter_slots;
+		new_map = NULL;
+		meter_levels = NULL;
+	}
+
+	/* Install the new map */
+	memcpy(private->meter_level_map, tmp_map, map.map_size * sizeof(s16));
+
+	return 0;
+}
+
+/* Set the Level Meter labels */
+static int fcp_ioctl_set_meter_labels(struct usb_mixer_interface *mixer,
+				      struct fcp_meter_labels __user *arg)
+{
+	struct fcp_meter_labels labels;
+	struct fcp_data *private = mixer->private_data;
+	unsigned int *tlv_data;
+	unsigned int tlv_size, data_size;
+
+	if (copy_from_user(&labels, arg, sizeof(labels)))
+		return -EFAULT;
+
+	/* Remove existing labels if size is zero */
+	if (!labels.labels_size) {
+
+		/* Clear TLV read/callback bits if labels were present */
+		if (private->meter_labels_tlv) {
+			private->meter_ctl->vd[0].access &=
+				~(SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+				  SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
+			snd_ctl_notify(mixer->chip->card,
+				       SNDRV_CTL_EVENT_MASK_INFO,
+				       &private->meter_ctl->id);
+		}
+
+		kfree(private->meter_labels_tlv);
+		private->meter_labels_tlv = NULL;
+		private->meter_labels_tlv_size = 0;
+
+		return 0;
+	}
+
+	/* Validate size */
+	if (labels.labels_size > 4096)
+		return -EINVAL;
+
+	/* Calculate padded data size */
+	data_size = ALIGN(labels.labels_size, sizeof(unsigned int));
+
+	/* Calculate total TLV size including header */
+	tlv_size = sizeof(unsigned int) * 2 + data_size;
+
+	/* Allocate, set up TLV header, and copy the labels data */
+	tlv_data = kzalloc(tlv_size, GFP_KERNEL);
+	if (!tlv_data)
+		return -ENOMEM;
+	tlv_data[0] = SNDRV_CTL_TLVT_FCP_CHANNEL_LABELS;
+	tlv_data[1] = data_size;
+	if (copy_from_user(&tlv_data[2], arg->labels, labels.labels_size)) {
+		kfree(tlv_data);
+		return -EFAULT;
+	}
+
+	/* Set TLV read/callback bits if labels weren't present */
+	if (!private->meter_labels_tlv) {
+		private->meter_ctl->vd[0].access |=
+			SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+			SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+		snd_ctl_notify(mixer->chip->card,
+			       SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->meter_ctl->id);
+	}
+
+	/* Swap in the new labels */
+	kfree(private->meter_labels_tlv);
+	private->meter_labels_tlv = tlv_data;
+	private->meter_labels_tlv_size = tlv_size;
+
+	return 0;
+}
+
+static int fcp_hwdep_open(struct snd_hwdep *hw, struct file *file)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct fcp_data *private = mixer->private_data;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	private->file = file;
+
+	return 0;
+}
+
+static int fcp_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
+			   unsigned int cmd, unsigned long arg)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct fcp_data *private = mixer->private_data;
+	void __user *argp = (void __user *)arg;
+
+	guard(mutex)(&private->mutex);
+
+	switch (cmd) {
+
+	case FCP_IOCTL_PVERSION:
+		return put_user(FCP_HWDEP_VERSION,
+				(int __user *)argp) ? -EFAULT : 0;
+		break;
+
+	case FCP_IOCTL_INIT:
+		return fcp_ioctl_init(mixer, argp);
+
+	case FCP_IOCTL_CMD:
+		if (!private->init)
+			return -EINVAL;
+		return fcp_ioctl_cmd(mixer, argp);
+
+	case FCP_IOCTL_SET_METER_MAP:
+		if (!private->init)
+			return -EINVAL;
+		return fcp_ioctl_set_meter_map(mixer, argp);
+
+	case FCP_IOCTL_SET_METER_LABELS:
+		if (!private->init)
+			return -EINVAL;
+		if (!private->meter_ctl)
+			return -EINVAL;
+		return fcp_ioctl_set_meter_labels(mixer, argp);
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	/* not reached */
+}
+
+static long fcp_hwdep_read(struct snd_hwdep *hw, char __user *buf,
+			   long count, loff_t *offset)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct fcp_data *private = mixer->private_data;
+	long ret = 0;
+	u32 event;
+
+	if (count < sizeof(event))
+		return -EINVAL;
+
+	ret = wait_event_interruptible(private->notify.queue,
+				       private->notify.event);
+	if (ret)
+		return ret;
+
+	scoped_guard(spinlock_irqsave, &private->notify.lock) {
+		event = private->notify.event;
+		private->notify.event = 0;
+	}
+
+	if (copy_to_user(buf, &event, sizeof(event)))
+		return -EFAULT;
+
+	return sizeof(event);
+}
+
+static __poll_t fcp_hwdep_poll(struct snd_hwdep *hw,
+			       struct file *file,
+			       poll_table *wait)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct fcp_data *private = mixer->private_data;
+	__poll_t mask = 0;
+
+	poll_wait(file, &private->notify.queue, wait);
+
+	if (private->notify.event)
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	return mask;
+}
+
+static int fcp_hwdep_release(struct snd_hwdep *hw, struct file *file)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct fcp_data *private = mixer->private_data;
+
+	if (!private)
+		return 0;
+
+	private->file = NULL;
+
+	return 0;
+}
+
+static int fcp_hwdep_init(struct usb_mixer_interface *mixer)
+{
+	struct snd_hwdep *hw;
+	int err;
+
+	err = snd_hwdep_new(mixer->chip->card, "Focusrite Control", 0, &hw);
+	if (err < 0)
+		return err;
+
+	hw->private_data = mixer;
+	hw->exclusive = 1;
+	hw->ops.open = fcp_hwdep_open;
+	hw->ops.ioctl = fcp_hwdep_ioctl;
+	hw->ops.ioctl_compat = fcp_hwdep_ioctl;
+	hw->ops.read = fcp_hwdep_read;
+	hw->ops.poll = fcp_hwdep_poll;
+	hw->ops.release = fcp_hwdep_release;
+
+	return 0;
+}
+
+/*** Cleanup ***/
+
+static void fcp_cleanup_urb(struct usb_mixer_interface *mixer)
+{
+	struct fcp_data *private = mixer->private_data;
+
+	if (!private->urb)
+		return;
+
+	usb_kill_urb(private->urb);
+	kfree(private->urb->transfer_buffer);
+	usb_free_urb(private->urb);
+	private->urb = NULL;
+}
+
+static void fcp_private_free(struct usb_mixer_interface *mixer)
+{
+	struct fcp_data *private = mixer->private_data;
+
+	fcp_cleanup_urb(mixer);
+
+	kfree(private->meter_level_map);
+	kfree(private->meter_levels);
+	kfree(private->meter_labels_tlv);
+	kfree(private);
+	mixer->private_data = NULL;
+}
+
+static void fcp_private_suspend(struct usb_mixer_interface *mixer)
+{
+	fcp_cleanup_urb(mixer);
+}
+
+/*** Callbacks ***/
+
+static void fcp_notify(struct urb *urb)
+{
+	struct usb_mixer_interface *mixer = urb->context;
+	struct fcp_data *private = mixer->private_data;
+	int len = urb->actual_length;
+	int ustatus = urb->status;
+	u32 data;
+
+	if (ustatus != 0 || len != 8)
+		goto requeue;
+
+	data = le32_to_cpu(*(__le32 *)urb->transfer_buffer);
+
+	/* Handle command acknowledgement */
+	if (data & FCP_NOTIFY_ACK) {
+		complete(&private->cmd_done);
+		data &= ~FCP_NOTIFY_ACK;
+	}
+
+	if (data) {
+		scoped_guard(spinlock_irqsave, &private->notify.lock) {
+			private->notify.event |= data;
+		}
+
+		wake_up_interruptible(&private->notify.queue);
+	}
+
+requeue:
+	if (ustatus != -ENOENT &&
+	    ustatus != -ECONNRESET &&
+	    ustatus != -ESHUTDOWN) {
+		urb->dev = mixer->chip->dev;
+		usb_submit_urb(urb, GFP_ATOMIC);
+	} else {
+		complete(&private->cmd_done);
+	}
+}
+
+/* Submit a URB to receive notifications from the device */
+static int fcp_init_notify(struct usb_mixer_interface *mixer)
+{
+	struct usb_device *dev = mixer->chip->dev;
+	struct fcp_data *private = mixer->private_data;
+	unsigned int pipe = usb_rcvintpipe(dev, private->bEndpointAddress);
+	void *transfer_buffer;
+	int err;
+
+	/* Already set up */
+	if (private->urb)
+		return 0;
+
+	if (usb_pipe_type_check(dev, pipe))
+		return -EINVAL;
+
+	private->urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!private->urb)
+		return -ENOMEM;
+
+	transfer_buffer = kmalloc(private->wMaxPacketSize, GFP_KERNEL);
+	if (!transfer_buffer) {
+		usb_free_urb(private->urb);
+		private->urb = NULL;
+		return -ENOMEM;
+	}
+
+	usb_fill_int_urb(private->urb, dev, pipe,
+			 transfer_buffer, private->wMaxPacketSize,
+			 fcp_notify, mixer, private->bInterval);
+
+	reinit_completion(&private->cmd_done);
+
+	err = usb_submit_urb(private->urb, GFP_KERNEL);
+	if (err) {
+		usb_audio_err(mixer->chip,
+			      "%s: usb_submit_urb failed: %d\n",
+			      __func__, err);
+		kfree(transfer_buffer);
+		usb_free_urb(private->urb);
+		private->urb = NULL;
+	}
+
+	return err;
+}
+
+/*** Initialisation ***/
+
+static int fcp_init(struct usb_mixer_interface *mixer,
+		    void *step0_resp, void *step2_resp)
+{
+	struct fcp_data *private = mixer->private_data;
+	struct usb_device *dev = mixer->chip->dev;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(mixer->chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+		FCP_USB_REQ_STEP0,
+		USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+		0, private->bInterfaceNumber,
+		step0_resp, private->step0_resp_size);
+	if (err < 0)
+		return err;
+	if (err != private->step0_resp_size)
+		return -EIO;
+
+	err = fcp_init_notify(mixer);
+	if (err < 0)
+		return err;
+
+	private->seq = 0;
+	private->init = 1;
+
+	err = fcp_usb(mixer, private->init1_opcode, NULL, 0, NULL, 0);
+	if (err < 0)
+		return err;
+
+	err = fcp_usb(mixer, private->init2_opcode,
+		      NULL, 0, step2_resp, private->step2_resp_size);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static int fcp_init_private(struct usb_mixer_interface *mixer)
+{
+	struct fcp_data *private =
+		kzalloc_obj(struct fcp_data);
+
+	if (!private)
+		return -ENOMEM;
+
+	mutex_init(&private->mutex);
+	init_completion(&private->cmd_done);
+	init_waitqueue_head(&private->notify.queue);
+	spin_lock_init(&private->notify.lock);
+
+	mixer->private_data = private;
+	mixer->private_free = fcp_private_free;
+	mixer->private_suspend = fcp_private_suspend;
+
+	private->mixer = mixer;
+
+	return 0;
+}
+
+/* Look through the interface descriptors for the Focusrite Control
+ * interface (bInterfaceClass = 255 Vendor Specific Class) and set
+ * bInterfaceNumber, bEndpointAddress, wMaxPacketSize, and bInterval
+ * in private
+ */
+static int fcp_find_fc_interface(struct usb_mixer_interface *mixer)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	struct fcp_data *private = mixer->private_data;
+	struct usb_host_config *config = chip->dev->actconfig;
+	int i;
+
+	for (i = 0; i < config->desc.bNumInterfaces; i++) {
+		struct usb_interface *intf = config->interface[i];
+		struct usb_interface_descriptor *desc =
+			&intf->altsetting[0].desc;
+		struct usb_endpoint_descriptor *epd;
+
+		if (desc->bInterfaceClass != 255)
+			continue;
+		if (desc->bNumEndpoints < 1)
+			continue;
+
+		epd = get_endpoint(intf->altsetting, 0);
+		private->bInterfaceNumber = desc->bInterfaceNumber;
+		private->bEndpointAddress = usb_endpoint_num(epd);
+		private->wMaxPacketSize = le16_to_cpu(epd->wMaxPacketSize);
+		private->bInterval = epd->bInterval;
+		return 0;
+	}
+
+	usb_audio_err(chip, "Focusrite vendor-specific interface not found\n");
+	return -EINVAL;
+}
+
+int snd_fcp_init(struct usb_mixer_interface *mixer)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+
+	/* only use UAC_VERSION_2 */
+	if (!mixer->protocol)
+		return 0;
+
+	err = fcp_init_private(mixer);
+	if (err < 0)
+		return err;
+
+	err = fcp_find_fc_interface(mixer);
+	if (err < 0)
+		return err;
+
+	err = fcp_hwdep_init(mixer);
+	if (err < 0)
+		return err;
+
+	usb_audio_info(chip,
+		"Focusrite Control Protocol Driver ready (pid=0x%04x); "
+		"report any issues to "
+		"https://github.com/geoffreybennett/fcp-support/issues",
+		USB_ID_PRODUCT(chip->usb_id));
+
+	return err;
+}
diff --git a/sound/usb/fcp.h b/sound/usb/fcp.h
new file mode 100644
index 000000000..d58cc7db7
--- /dev/null
+++ b/sound/usb/fcp.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_FCP_H
+#define __USBAUDIO_FCP_H
+
+int snd_fcp_init(struct usb_mixer_interface *mixer);
+
+#endif /* __USBAUDIO_FCP_H */
diff --git a/sound/usb/format.c b/sound/usb/format.c
new file mode 100644
index 000000000..4830f9f93
--- /dev/null
+++ b/sound/usb/format.c
@@ -0,0 +1,923 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "quirks.h"
+#include "helper.h"
+#include "clock.h"
+#include "format.h"
+
+/*
+ * parse the audio format type I descriptor
+ * and returns the corresponding pcm format
+ *
+ * @dev: usb device
+ * @fp: audioformat record
+ * @format: the format tag (wFormatTag)
+ * @fmt: the format type descriptor (v1/v2) or AudioStreaming descriptor (v3)
+ */
+static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
+				     struct audioformat *fp,
+				     u64 format, void *_fmt)
+{
+	int sample_width, sample_bytes;
+	u64 pcm_formats = 0;
+	u64 dsd_formats = 0;
+
+	switch (fp->protocol) {
+	case UAC_VERSION_1:
+	default: {
+		struct uac_format_type_i_discrete_descriptor *fmt = _fmt;
+		if (format >= 64) {
+			usb_audio_info(chip,
+				       "%u:%d: invalid format type 0x%llx is detected, processed as PCM\n",
+				       fp->iface, fp->altsetting, format);
+			format = UAC_FORMAT_TYPE_I_PCM;
+		}
+		sample_width = fmt->bBitResolution;
+		sample_bytes = fmt->bSubframeSize;
+		format = 1ULL << format;
+		break;
+	}
+
+	case UAC_VERSION_2: {
+		struct uac_format_type_i_ext_descriptor *fmt = _fmt;
+		sample_width = fmt->bBitResolution;
+		sample_bytes = fmt->bSubslotSize;
+
+		if (format & UAC2_FORMAT_TYPE_I_RAW_DATA) {
+			pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
+			/* flag potentially raw DSD capable altsettings */
+			fp->dsd_raw = true;
+			/* clear special format bit to avoid "unsupported format" msg below */
+			format &= ~UAC2_FORMAT_TYPE_I_RAW_DATA;
+		}
+
+		format <<= 1;
+		break;
+	}
+	case UAC_VERSION_3: {
+		struct uac3_as_header_descriptor *as = _fmt;
+
+		sample_width = as->bBitResolution;
+		sample_bytes = as->bSubslotSize;
+
+		if (format & UAC3_FORMAT_TYPE_I_RAW_DATA) {
+			pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
+			/* clear special format bit to avoid "unsupported format" msg below */
+			format &= ~UAC3_FORMAT_TYPE_I_RAW_DATA;
+		}
+
+		format <<= 1;
+		break;
+	}
+	}
+
+	fp->fmt_bits = sample_width;
+	fp->fmt_sz = sample_bytes;
+
+	if ((pcm_formats == 0) &&
+	    (format == 0 || format == BIT(UAC_FORMAT_TYPE_I_UNDEFINED))) {
+		/* some devices don't define this correctly... */
+		usb_audio_info(chip, "%u:%d : format type 0 is detected, processed as PCM\n",
+			fp->iface, fp->altsetting);
+		format = BIT(UAC_FORMAT_TYPE_I_PCM);
+	}
+	if (format & BIT(UAC_FORMAT_TYPE_I_PCM)) {
+		if (((chip->usb_id == USB_ID(0x0582, 0x0016)) ||
+		     /* Edirol SD-90 */
+		     (chip->usb_id == USB_ID(0x0582, 0x000c))) &&
+		     /* Roland SC-D70 */
+		    sample_width == 24 && sample_bytes == 2)
+			sample_bytes = 3;
+		else if (sample_width > sample_bytes * 8) {
+			usb_audio_info(chip, "%u:%d : sample bitwidth %d in over sample bytes %d\n",
+				 fp->iface, fp->altsetting,
+				 sample_width, sample_bytes);
+		}
+		/* check the format byte size */
+		switch (sample_bytes) {
+		case 1:
+			pcm_formats |= SNDRV_PCM_FMTBIT_S8;
+			break;
+		case 2:
+			if (snd_usb_is_big_endian_format(chip, fp))
+				pcm_formats |= SNDRV_PCM_FMTBIT_S16_BE; /* grrr, big endian!! */
+			else
+				pcm_formats |= SNDRV_PCM_FMTBIT_S16_LE;
+			break;
+		case 3:
+			if (snd_usb_is_big_endian_format(chip, fp))
+				pcm_formats |= SNDRV_PCM_FMTBIT_S24_3BE; /* grrr, big endian!! */
+			else
+				pcm_formats |= SNDRV_PCM_FMTBIT_S24_3LE;
+			break;
+		case 4:
+			pcm_formats |= SNDRV_PCM_FMTBIT_S32_LE;
+			break;
+		default:
+			usb_audio_info(chip,
+				 "%u:%d : unsupported sample bitwidth %d in %d bytes\n",
+				 fp->iface, fp->altsetting,
+				 sample_width, sample_bytes);
+			break;
+		}
+	}
+	if (format & BIT(UAC_FORMAT_TYPE_I_PCM8)) {
+		/* Dallas DS4201 workaround: it advertises U8 format, but really
+		   supports S8. */
+		if (chip->usb_id == USB_ID(0x04fa, 0x4201))
+			pcm_formats |= SNDRV_PCM_FMTBIT_S8;
+		else
+			pcm_formats |= SNDRV_PCM_FMTBIT_U8;
+	}
+	if (format & BIT(UAC_FORMAT_TYPE_I_IEEE_FLOAT))
+		pcm_formats |= SNDRV_PCM_FMTBIT_FLOAT_LE;
+	if (format & BIT(UAC_FORMAT_TYPE_I_ALAW))
+		pcm_formats |= SNDRV_PCM_FMTBIT_A_LAW;
+	if (format & BIT(UAC_FORMAT_TYPE_I_MULAW))
+		pcm_formats |= SNDRV_PCM_FMTBIT_MU_LAW;
+	if (format & ~0x3f) {
+		usb_audio_info(chip,
+			 "%u:%d : unsupported format bits %#llx\n",
+			 fp->iface, fp->altsetting, format);
+	}
+
+	dsd_formats |= snd_usb_interface_dsd_format_quirks(chip, fp, sample_bytes);
+	if (dsd_formats && !fp->dsd_dop)
+		pcm_formats = dsd_formats;
+
+	return pcm_formats;
+}
+
+static int set_fixed_rate(struct audioformat *fp, int rate, int rate_bits)
+{
+	kfree(fp->rate_table);
+	fp->rate_table = kmalloc(sizeof(int), GFP_KERNEL);
+	if (!fp->rate_table)
+		return -ENOMEM;
+	fp->nr_rates = 1;
+	fp->rate_min = rate;
+	fp->rate_max = rate;
+	fp->rates = rate_bits;
+	fp->rate_table[0] = rate;
+	return 0;
+}
+
+/* set up rate_min, rate_max and rates from the rate table */
+static void set_rate_table_min_max(struct audioformat *fp)
+{
+	unsigned int rate;
+	int i;
+
+	fp->rate_min = INT_MAX;
+	fp->rate_max = 0;
+	fp->rates = 0;
+	for (i = 0; i < fp->nr_rates; i++) {
+		rate = fp->rate_table[i];
+		fp->rate_min = min(fp->rate_min, rate);
+		fp->rate_max = max(fp->rate_max, rate);
+		fp->rates |= snd_pcm_rate_to_rate_bit(rate);
+	}
+}
+
+/*
+ * parse the format descriptor and stores the possible sample rates
+ * on the audioformat table (audio class v1).
+ *
+ * @dev: usb device
+ * @fp: audioformat record
+ * @fmt: the format descriptor
+ * @offset: the start offset of descriptor pointing the rate type
+ *          (7 for type I and II, 8 for type II)
+ */
+static int parse_audio_format_rates_v1(struct snd_usb_audio *chip, struct audioformat *fp,
+				       unsigned char *fmt, int offset)
+{
+	int nr_rates = fmt[offset];
+
+	if (fmt[0] < offset + 1 + 3 * (nr_rates ? nr_rates : 2)) {
+		usb_audio_err(chip,
+			"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
+			fp->iface, fp->altsetting);
+		return -EINVAL;
+	}
+
+	if (nr_rates) {
+		/*
+		 * build the rate table and bitmap flags
+		 */
+		int r, idx;
+
+		fp->rate_table = kmalloc_array(nr_rates, sizeof(int),
+					       GFP_KERNEL);
+		if (fp->rate_table == NULL)
+			return -ENOMEM;
+
+		fp->nr_rates = 0;
+		for (r = 0, idx = offset + 1; r < nr_rates; r++, idx += 3) {
+			unsigned int rate = combine_triple(&fmt[idx]);
+			if (!rate)
+				continue;
+			/* C-Media CM6501 mislabels its 96 kHz altsetting */
+			/* Terratec Aureon 7.1 USB C-Media 6206, too */
+			/* Ozone Z90 USB C-Media, too */
+			if (rate == 48000 && nr_rates == 1 &&
+			    (chip->usb_id == USB_ID(0x0d8c, 0x0201) ||
+			     chip->usb_id == USB_ID(0x0d8c, 0x0102) ||
+			     chip->usb_id == USB_ID(0x0d8c, 0x0078) ||
+			     chip->usb_id == USB_ID(0x0ccd, 0x00b1)) &&
+			    fp->altsetting == 5 && fp->maxpacksize == 392)
+				rate = 96000;
+			/* Creative VF0420/VF0470 Live Cams report 16 kHz instead of 8kHz */
+			if (rate == 16000 &&
+			    (chip->usb_id == USB_ID(0x041e, 0x4064) ||
+			     chip->usb_id == USB_ID(0x041e, 0x4068)))
+				rate = 8000;
+
+			fp->rate_table[fp->nr_rates++] = rate;
+		}
+		if (!fp->nr_rates) {
+			usb_audio_info(chip,
+				       "%u:%d: All rates were zero\n",
+				       fp->iface, fp->altsetting);
+			return -EINVAL;
+		}
+		set_rate_table_min_max(fp);
+	} else {
+		/* continuous rates */
+		fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
+		fp->rate_min = combine_triple(&fmt[offset + 1]);
+		fp->rate_max = combine_triple(&fmt[offset + 4]);
+	}
+
+	/* Jabra Evolve 65 headset */
+	if (chip->usb_id == USB_ID(0x0b0e, 0x030b) ||
+	    chip->usb_id == USB_ID(0x0b0e, 0x030c)) {
+		/* only 48kHz for playback while keeping 16kHz for capture */
+		if (fp->nr_rates != 1)
+			return set_fixed_rate(fp, 48000, SNDRV_PCM_RATE_48000);
+	}
+
+	return 0;
+}
+
+
+/*
+ * Presonus Studio 1810c supports a limited set of sampling
+ * rates per altsetting but reports the full set each time.
+ * If we don't filter out the unsupported rates and attempt
+ * to configure the card, it will hang refusing to do any
+ * further audio I/O until a hard reset is performed.
+ *
+ * The list of supported rates per altsetting (set of available
+ * I/O channels) is described in the owner's manual, section 2.2.
+ */
+static bool s1810c_valid_sample_rate(struct audioformat *fp,
+				     unsigned int rate)
+{
+	switch (fp->altsetting) {
+	case 1:
+		/* All ADAT ports available */
+		return rate <= 48000;
+	case 2:
+		/* Half of ADAT ports available */
+		return (rate == 88200 || rate == 96000);
+	case 3:
+		/* Analog I/O only (no S/PDIF nor ADAT) */
+		return rate >= 176400;
+	default:
+		return false;
+	}
+	return false;
+}
+
+/*
+ * Focusrite devices use rate pairs: 44100/48000, 88200/96000, and
+ * 176400/192000. Return true if rate is in the pair for max_rate.
+ */
+static bool focusrite_rate_pair(unsigned int rate,
+				unsigned int max_rate)
+{
+	switch (max_rate) {
+	case 48000:  return rate == 44100 || rate == 48000;
+	case 96000:  return rate == 88200 || rate == 96000;
+	case 192000: return rate == 176400 || rate == 192000;
+	default:     return true;
+	}
+}
+
+/*
+ * Focusrite devices report all supported rates in a single clock
+ * source but only a subset is valid per altsetting.
+ *
+ * Detection uses two descriptor features:
+ *
+ * 1. Format Type descriptor bLength == 10: non-standard extension
+ *    with max sample rate in bytes 6..9.
+ *
+ * 2. bmControls VAL_ALT_SETTINGS readable bit: when set, the device
+ *    only supports the highest rate pair for that altsetting, and when
+ *    clear, all rates up to max_rate are valid.
+ *
+ * For devices without the bLength == 10 extension but with
+ * VAL_ALT_SETTINGS readable and multiple altsettings (only seen in
+ * Scarlett 18i8 3rd Gen playback), fall back to the Focusrite
+ * convention: alt 1 = 48kHz, alt 2 = 96kHz, alt 3 = 192kHz.
+ */
+static bool focusrite_valid_sample_rate(struct snd_usb_audio *chip,
+					struct audioformat *fp,
+					unsigned int rate)
+{
+	struct usb_interface *iface;
+	struct usb_host_interface *alts;
+	struct uac2_as_header_descriptor *as;
+	unsigned char *fmt;
+	unsigned int max_rate;
+	bool val_alt;
+
+	alts = snd_usb_get_host_interface(chip, fp->iface, fp->altsetting);
+	if (!alts)
+		return true;
+
+	fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+				      NULL, UAC_FORMAT_TYPE);
+	if (!fmt)
+		return true;
+
+	as = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+				     NULL, UAC_AS_GENERAL);
+	if (!as)
+		return true;
+
+	val_alt = uac_v2v3_control_is_readable(as->bmControls,
+					       UAC2_AS_VAL_ALT_SETTINGS);
+
+	if (fmt[0] == 10) { /* bLength */
+		max_rate = combine_quad(&fmt[6]);
+
+		if (val_alt)
+			return focusrite_rate_pair(rate, max_rate);
+
+		/* No val_alt: rates fall through from higher */
+		switch (max_rate) {
+		case 192000:
+			if (rate == 176400 || rate == 192000)
+				return true;
+			fallthrough;
+		case 96000:
+			if (rate == 88200 || rate == 96000)
+				return true;
+			fallthrough;
+		case 48000:
+			return (rate == 44100 || rate == 48000);
+		default:
+			usb_audio_info(chip,
+				"%u:%d : unexpected max rate: %u\n",
+				fp->iface, fp->altsetting, max_rate);
+			return true;
+		}
+	}
+
+	if (!val_alt)
+		return true;
+
+	/* Multi-altsetting device with val_alt but no max_rate
+	 * in the format descriptor. Use Focusrite convention:
+	 * alt 1 = 48kHz, alt 2 = 96kHz, alt 3 = 192kHz.
+	 */
+	iface = usb_ifnum_to_if(chip->dev, fp->iface);
+	if (!iface || iface->num_altsetting <= 2)
+		return true;
+
+	switch (fp->altsetting) {
+	case 1:		max_rate = 48000; break;
+	case 2:		max_rate = 96000; break;
+	case 3:		max_rate = 192000; break;
+	default:	return true;
+	}
+
+	return focusrite_rate_pair(rate, max_rate);
+}
+
+/*
+ * Helper function to walk the array of sample rate triplets reported by
+ * the device. The problem is that we need to parse whole array first to
+ * get to know how many sample rates we have to expect.
+ * Then fp->rate_table can be allocated and filled.
+ */
+static int parse_uac2_sample_rate_range(struct snd_usb_audio *chip,
+					struct audioformat *fp, int nr_triplets,
+					const unsigned char *data)
+{
+	int i, nr_rates = 0;
+
+	for (i = 0; i < nr_triplets; i++) {
+		int min = combine_quad(&data[2 + 12 * i]);
+		int max = combine_quad(&data[6 + 12 * i]);
+		int res = combine_quad(&data[10 + 12 * i]);
+		unsigned int rate;
+
+		if ((max < 0) || (min < 0) || (res < 0) || (max < min))
+			continue;
+
+		/*
+		 * for ranges with res == 1, we announce a continuous sample
+		 * rate range, and this function should return 0 for no further
+		 * parsing.
+		 */
+		if (res == 1) {
+			fp->rate_min = min;
+			fp->rate_max = max;
+			fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
+			return 0;
+		}
+
+		for (rate = min; rate <= max; rate += res) {
+
+			/* Filter out invalid rates on Presonus Studio 1810c */
+			if (chip->usb_id == USB_ID(0x194f, 0x010c) &&
+			    !s1810c_valid_sample_rate(fp, rate))
+				goto skip_rate;
+			/* Filter out invalid rates on Presonus Studio 1824c */
+			if (chip->usb_id == USB_ID(0x194f, 0x010d) &&
+			    !s1810c_valid_sample_rate(fp, rate))
+				goto skip_rate;
+			/* Filter out invalid rates on Presonus Studio 1824 */
+			if (chip->usb_id == USB_ID(0x194f, 0x0107) &&
+			    !s1810c_valid_sample_rate(fp, rate))
+				goto skip_rate;
+
+			/* Filter out invalid rates on Focusrite devices */
+			if (USB_ID_VENDOR(chip->usb_id) == 0x1235 &&
+			    !focusrite_valid_sample_rate(chip, fp, rate))
+				goto skip_rate;
+
+			if (fp->rate_table)
+				fp->rate_table[nr_rates] = rate;
+			nr_rates++;
+			if (nr_rates >= MAX_NR_RATES) {
+				usb_audio_err(chip, "invalid uac2 rates\n");
+				return nr_rates;
+			}
+
+skip_rate:
+			/* avoid endless loop */
+			if (res == 0)
+				break;
+		}
+	}
+
+	return nr_rates;
+}
+
+/* Line6 Helix series and the Rode Rodecaster Pro don't support the
+ * UAC2_CS_RANGE usb function call. Return a static table of known
+ * clock rates.
+ */
+static int line6_parse_audio_format_rates_quirk(struct snd_usb_audio *chip,
+						struct audioformat *fp)
+{
+	switch (chip->usb_id) {
+	case USB_ID(0x0e41, 0x4241): /* Line6 Helix */
+	case USB_ID(0x0e41, 0x4242): /* Line6 Helix Rack */
+	case USB_ID(0x0e41, 0x4244): /* Line6 Helix LT */
+	case USB_ID(0x0e41, 0x4246): /* Line6 HX-Stomp */
+	case USB_ID(0x0e41, 0x4253): /* Line6 HX-Stomp XL */
+	case USB_ID(0x0e41, 0x4247): /* Line6 Pod Go */
+	case USB_ID(0x0e41, 0x4248): /* Line6 Helix >= fw 2.82 */
+	case USB_ID(0x0e41, 0x4249): /* Line6 Helix Rack >= fw 2.82 */
+	case USB_ID(0x0e41, 0x424a): /* Line6 Helix LT >= fw 2.82 */
+	case USB_ID(0x0e41, 0x424b): /* Line6 Pod Go */
+	case USB_ID(0x19f7, 0x0011): /* Rode Rodecaster Pro */
+		return set_fixed_rate(fp, 48000, SNDRV_PCM_RATE_48000);
+	}
+
+	return -ENODEV;
+}
+
+/* check whether the given altsetting is supported for the already set rate */
+static bool check_valid_altsetting_v2v3(struct snd_usb_audio *chip, int iface,
+					int altsetting)
+{
+	struct usb_device *dev = chip->dev;
+	__le64 raw_data = 0;
+	u64 data;
+	int err;
+
+	/* we assume 64bit is enough for any altsettings */
+	if (snd_BUG_ON(altsetting >= 64 - 8))
+		return false;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			      UAC2_AS_VAL_ALT_SETTINGS << 8,
+			      iface, &raw_data, sizeof(raw_data));
+	if (err < 0)
+		return false;
+
+	data = le64_to_cpu(raw_data);
+	/* first byte contains the bitmap size */
+	if ((data & 0xff) * 8 < altsetting)
+		return false;
+	if (data & (1ULL << (altsetting + 8)))
+		return true;
+
+	return false;
+}
+
+/*
+ * Validate each sample rate with the altsetting
+ * Rebuild the rate table if only partial values are valid
+ */
+static int validate_sample_rate_table_v2v3(struct snd_usb_audio *chip,
+					   struct audioformat *fp,
+					   int clock)
+{
+	struct usb_device *dev = chip->dev;
+	struct usb_host_interface *alts;
+	unsigned int *table;
+	unsigned int nr_rates;
+	int i, err;
+	u32 bmControls;
+
+	/* performing the rate verification may lead to unexpected USB bus
+	 * behavior afterwards by some unknown reason.  Do this only for the
+	 * known devices.
+	 */
+	if (!(chip->quirk_flags & QUIRK_FLAG_VALIDATE_RATES))
+		return 0; /* don't perform the validation as default */
+
+	alts = snd_usb_get_host_interface(chip, fp->iface, fp->altsetting);
+	if (!alts)
+		return 0;
+
+	if (fp->protocol == UAC_VERSION_3) {
+		struct uac3_as_header_descriptor *as = snd_usb_find_csint_desc(
+				alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
+		bmControls = le32_to_cpu(as->bmControls);
+	} else {
+		struct uac2_as_header_descriptor *as = snd_usb_find_csint_desc(
+				alts->extra, alts->extralen, NULL, UAC_AS_GENERAL);
+		bmControls = as->bmControls;
+	}
+
+	if (!uac_v2v3_control_is_readable(bmControls,
+				UAC2_AS_VAL_ALT_SETTINGS))
+		return 0;
+
+	table = kcalloc(fp->nr_rates, sizeof(*table), GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	/* clear the interface altsetting at first */
+	usb_set_interface(dev, fp->iface, 0);
+
+	nr_rates = 0;
+	for (i = 0; i < fp->nr_rates; i++) {
+		err = snd_usb_set_sample_rate_v2v3(chip, fp, clock,
+						   fp->rate_table[i]);
+		if (err < 0)
+			continue;
+
+		if (check_valid_altsetting_v2v3(chip, fp->iface, fp->altsetting))
+			table[nr_rates++] = fp->rate_table[i];
+	}
+
+	if (!nr_rates) {
+		usb_audio_dbg(chip,
+			      "No valid sample rate available for %d:%d, assuming a firmware bug\n",
+			      fp->iface, fp->altsetting);
+		nr_rates = fp->nr_rates; /* continue as is */
+	}
+
+	if (fp->nr_rates == nr_rates) {
+		kfree(table);
+		return 0;
+	}
+
+	kfree(fp->rate_table);
+	fp->rate_table = table;
+	fp->nr_rates = nr_rates;
+	return 0;
+}
+
+/*
+ * parse the format descriptor and stores the possible sample rates
+ * on the audioformat table (audio class v2 and v3).
+ */
+static int parse_audio_format_rates_v2v3(struct snd_usb_audio *chip,
+				       struct audioformat *fp)
+{
+	struct usb_device *dev = chip->dev;
+	unsigned char tmp[2], *data;
+	int nr_triplets, data_size, ret = 0, ret_l6;
+	int clock = snd_usb_clock_find_source(chip, fp, false);
+	struct usb_host_interface *ctrl_intf;
+
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, fp->iface);
+	if (clock < 0) {
+		dev_err(&dev->dev,
+			"%s(): unable to find clock source (clock %d)\n",
+				__func__, clock);
+		goto err;
+	}
+
+	/* get the number of sample rates first by only fetching 2 bytes */
+	ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			      UAC2_CS_CONTROL_SAM_FREQ << 8,
+			      snd_usb_ctrl_intf(ctrl_intf) | (clock << 8),
+			      tmp, sizeof(tmp));
+
+	if (ret < 0) {
+		/* line6 helix devices don't support UAC2_CS_CONTROL_SAM_FREQ call */
+		ret_l6 = line6_parse_audio_format_rates_quirk(chip, fp);
+		if (ret_l6 == -ENODEV) {
+			/* no line6 device found continue showing the error */
+			dev_err(&dev->dev,
+				"%s(): unable to retrieve number of sample rates (clock %d)\n",
+				__func__, clock);
+			goto err;
+		}
+		if (ret_l6 == 0) {
+			dev_info(&dev->dev,
+				"%s(): unable to retrieve number of sample rates: set it to a predefined value (clock %d).\n",
+				__func__, clock);
+			return 0;
+		}
+		ret = ret_l6;
+		goto err;
+	}
+
+	nr_triplets = (tmp[1] << 8) | tmp[0];
+	data_size = 2 + 12 * nr_triplets;
+	data = kzalloc(data_size, GFP_KERNEL);
+	if (!data) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	/* now get the full information */
+	ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			      UAC2_CS_CONTROL_SAM_FREQ << 8,
+			      snd_usb_ctrl_intf(ctrl_intf) | (clock << 8),
+			      data, data_size);
+
+	if (ret < 0) {
+		dev_err(&dev->dev,
+			"%s(): unable to retrieve sample rate range (clock %d)\n",
+				__func__, clock);
+		ret = -EINVAL;
+		goto err_free;
+	}
+
+	/* Call the triplet parser, and make sure fp->rate_table is NULL.
+	 * We just use the return value to know how many sample rates we
+	 * will have to deal with. */
+	kfree(fp->rate_table);
+	fp->rate_table = NULL;
+	fp->nr_rates = parse_uac2_sample_rate_range(chip, fp, nr_triplets, data);
+
+	if (fp->nr_rates == 0) {
+		/* SNDRV_PCM_RATE_CONTINUOUS */
+		ret = 0;
+		goto err_free;
+	}
+
+	fp->rate_table = kmalloc_array(fp->nr_rates, sizeof(int), GFP_KERNEL);
+	if (!fp->rate_table) {
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	/* Call the triplet parser again, but this time, fp->rate_table is
+	 * allocated, so the rates will be stored */
+	parse_uac2_sample_rate_range(chip, fp, nr_triplets, data);
+
+	ret = validate_sample_rate_table_v2v3(chip, fp, clock);
+	if (ret < 0)
+		goto err_free;
+
+	set_rate_table_min_max(fp);
+
+err_free:
+	kfree(data);
+err:
+	return ret;
+}
+
+/*
+ * parse the format type I and III descriptors
+ */
+static int parse_audio_format_i(struct snd_usb_audio *chip,
+				struct audioformat *fp, u64 format,
+				void *_fmt)
+{
+	snd_pcm_format_t pcm_format;
+	unsigned int fmt_type;
+	int ret;
+
+	switch (fp->protocol) {
+	default:
+	case UAC_VERSION_1:
+	case UAC_VERSION_2: {
+		struct uac_format_type_i_continuous_descriptor *fmt = _fmt;
+
+		fmt_type = fmt->bFormatType;
+		break;
+	}
+	case UAC_VERSION_3: {
+		/* fp->fmt_type is already set in this case */
+		fmt_type = fp->fmt_type;
+		break;
+	}
+	}
+
+	if (fmt_type == UAC_FORMAT_TYPE_III) {
+		/* FIXME: the format type is really IECxxx
+		 *        but we give normal PCM format to get the existing
+		 *        apps working...
+		 */
+		switch (chip->usb_id) {
+
+		case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
+			if (chip->setup == 0x00 && 
+			    fp->altsetting == 6)
+				pcm_format = SNDRV_PCM_FORMAT_S16_BE;
+			else
+				pcm_format = SNDRV_PCM_FORMAT_S16_LE;
+			break;
+		default:
+			pcm_format = SNDRV_PCM_FORMAT_S16_LE;
+		}
+		fp->formats = pcm_format_to_bits(pcm_format);
+	} else {
+		fp->formats = parse_audio_format_i_type(chip, fp, format, _fmt);
+		if (!fp->formats)
+			return -EINVAL;
+	}
+
+	/* gather possible sample rates */
+	/* audio class v1 reports possible sample rates as part of the
+	 * proprietary class specific descriptor.
+	 * audio class v2 uses class specific EP0 range requests for that.
+	 */
+	switch (fp->protocol) {
+	default:
+	case UAC_VERSION_1: {
+		struct uac_format_type_i_continuous_descriptor *fmt = _fmt;
+
+		fp->channels = fmt->bNrChannels;
+		ret = parse_audio_format_rates_v1(chip, fp, (unsigned char *) fmt, 7);
+		break;
+	}
+	case UAC_VERSION_2:
+	case UAC_VERSION_3: {
+		/* fp->channels is already set in this case */
+		ret = parse_audio_format_rates_v2v3(chip, fp);
+		break;
+	}
+	}
+
+	if (fp->channels < 1) {
+		usb_audio_err(chip,
+			"%u:%d : invalid channels %d\n",
+			fp->iface, fp->altsetting, fp->channels);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+/*
+ * parse the format type II descriptor
+ */
+static int parse_audio_format_ii(struct snd_usb_audio *chip,
+				 struct audioformat *fp,
+				 u64 format, void *_fmt)
+{
+	int brate, framesize, ret;
+
+	switch (format) {
+	case UAC_FORMAT_TYPE_II_AC3:
+		/* FIXME: there is no AC3 format defined yet */
+		// fp->formats = SNDRV_PCM_FMTBIT_AC3;
+		fp->formats = SNDRV_PCM_FMTBIT_U8; /* temporary hack to receive byte streams */
+		break;
+	case UAC_FORMAT_TYPE_II_MPEG:
+		fp->formats = SNDRV_PCM_FMTBIT_MPEG;
+		break;
+	default:
+		usb_audio_info(chip,
+			 "%u:%d : unknown format tag %#llx is detected.  processed as MPEG.\n",
+			 fp->iface, fp->altsetting, format);
+		fp->formats = SNDRV_PCM_FMTBIT_MPEG;
+		break;
+	}
+
+	fp->channels = 1;
+
+	switch (fp->protocol) {
+	default:
+	case UAC_VERSION_1: {
+		struct uac_format_type_ii_discrete_descriptor *fmt = _fmt;
+		brate = le16_to_cpu(fmt->wMaxBitRate);
+		framesize = le16_to_cpu(fmt->wSamplesPerFrame);
+		usb_audio_info(chip, "found format II with max.bitrate = %d, frame size=%d\n", brate, framesize);
+		fp->frame_size = framesize;
+		ret = parse_audio_format_rates_v1(chip, fp, _fmt, 8); /* fmt[8..] sample rates */
+		break;
+	}
+	case UAC_VERSION_2: {
+		struct uac_format_type_ii_ext_descriptor *fmt = _fmt;
+		brate = le16_to_cpu(fmt->wMaxBitRate);
+		framesize = le16_to_cpu(fmt->wSamplesPerFrame);
+		usb_audio_info(chip, "found format II with max.bitrate = %d, frame size=%d\n", brate, framesize);
+		fp->frame_size = framesize;
+		ret = parse_audio_format_rates_v2v3(chip, fp);
+		break;
+	}
+	}
+
+	return ret;
+}
+
+int snd_usb_parse_audio_format(struct snd_usb_audio *chip,
+			       struct audioformat *fp, u64 format,
+			       struct uac_format_type_i_continuous_descriptor *fmt,
+			       int stream)
+{
+	int err;
+
+	switch (fmt->bFormatType) {
+	case UAC_FORMAT_TYPE_I:
+	case UAC_FORMAT_TYPE_III:
+		err = parse_audio_format_i(chip, fp, format, fmt);
+		break;
+	case UAC_FORMAT_TYPE_II:
+		err = parse_audio_format_ii(chip, fp, format, fmt);
+		break;
+	default:
+		usb_audio_info(chip,
+			 "%u:%d : format type %d is not supported yet\n",
+			 fp->iface, fp->altsetting,
+			 fmt->bFormatType);
+		return -ENOTSUPP;
+	}
+	fp->fmt_type = fmt->bFormatType;
+	if (err < 0)
+		return err;
+#if 1
+	/* FIXME: temporary hack for extigy/audigy 2 nx/zs */
+	/* extigy apparently supports sample rates other than 48k
+	 * but not in ordinary way.  so we enable only 48k atm.
+	 */
+	if (chip->usb_id == USB_ID(0x041e, 0x3000) ||
+	    chip->usb_id == USB_ID(0x041e, 0x3020) ||
+	    chip->usb_id == USB_ID(0x041e, 0x3061)) {
+		if (fmt->bFormatType == UAC_FORMAT_TYPE_I &&
+		    fp->rates != SNDRV_PCM_RATE_48000 &&
+		    fp->rates != SNDRV_PCM_RATE_96000)
+			return -ENOTSUPP;
+	}
+#endif
+	return 0;
+}
+
+int snd_usb_parse_audio_format_v3(struct snd_usb_audio *chip,
+			       struct audioformat *fp,
+			       struct uac3_as_header_descriptor *as,
+			       int stream)
+{
+	u64 format = le64_to_cpu(as->bmFormats);
+	int err;
+
+	/*
+	 * Type I format bits are D0..D6
+	 * This test works because type IV is not supported
+	 */
+	if (format & 0x7f)
+		fp->fmt_type = UAC_FORMAT_TYPE_I;
+	else
+		fp->fmt_type = UAC_FORMAT_TYPE_III;
+
+	err = parse_audio_format_i(chip, fp, format, as);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
diff --git a/sound/usb/format.h b/sound/usb/format.h
new file mode 100644
index 000000000..e70171892
--- /dev/null
+++ b/sound/usb/format.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_FORMAT_H
+#define __USBAUDIO_FORMAT_H
+
+int snd_usb_parse_audio_format(struct snd_usb_audio *chip,
+			       struct audioformat *fp, u64 format,
+			       struct uac_format_type_i_continuous_descriptor *fmt,
+			       int stream);
+
+int snd_usb_parse_audio_format_v3(struct snd_usb_audio *chip,
+			       struct audioformat *fp,
+			       struct uac3_as_header_descriptor *as,
+			       int stream);
+#endif /*  __USBAUDIO_FORMAT_H */
diff --git a/sound/usb/helper.c b/sound/usb/helper.c
new file mode 100644
index 000000000..497d2b27f
--- /dev/null
+++ b/sound/usb/helper.c
@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#include "usbaudio.h"
+#include "helper.h"
+#include "quirks.h"
+
+/*
+ * combine bytes and get an integer value
+ */
+unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
+{
+	switch (size) {
+	case 1:  return *bytes;
+	case 2:  return combine_word(bytes);
+	case 3:  return combine_triple(bytes);
+	case 4:  return combine_quad(bytes);
+	default: return 0;
+	}
+}
+
+/*
+ * parse descriptor buffer and return the pointer starting the given
+ * descriptor type.
+ */
+void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
+{
+	u8 *p, *end, *next;
+
+	p = descstart;
+	end = p + desclen;
+	for (; p < end;) {
+		if (p[0] < 2)
+			return NULL;
+		next = p + p[0];
+		if (next > end)
+			return NULL;
+		if (p[1] == dtype && (!after || (void *)p > after)) {
+			return p;
+		}
+		p = next;
+	}
+	return NULL;
+}
+
+/*
+ * find a class-specified interface descriptor with the given subtype.
+ */
+void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
+{
+	unsigned char *p = after;
+
+	while ((p = snd_usb_find_desc(buffer, buflen, p,
+				      USB_DT_CS_INTERFACE)) != NULL) {
+		if (p[0] >= 3 && p[2] == dsubtype)
+			return p;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(snd_usb_find_csint_desc);
+
+/*
+ * Wrapper for usb_control_msg().
+ * Allocates a temp buffer to prevent dmaing from/to the stack.
+ */
+int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
+		    __u8 requesttype, __u16 value, __u16 index, void *data,
+		    __u16 size)
+{
+	int err;
+	void *buf = NULL;
+	int timeout;
+
+	if (usb_pipe_type_check(dev, pipe))
+		return -EINVAL;
+
+	if (size > 0) {
+		buf = kmemdup(data, size, GFP_KERNEL);
+		if (!buf)
+			return -ENOMEM;
+	}
+
+	if (requesttype & USB_DIR_IN)
+		timeout = USB_CTRL_GET_TIMEOUT;
+	else
+		timeout = USB_CTRL_SET_TIMEOUT;
+
+	err = usb_control_msg(dev, pipe, request, requesttype,
+			      value, index, buf, size, timeout);
+
+	if (size > 0) {
+		memcpy(data, buf, size);
+		kfree(buf);
+	}
+
+	snd_usb_ctl_msg_quirk(dev, pipe, request, requesttype,
+			      value, index, data, size);
+
+	return err;
+}
+
+unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
+					 struct usb_host_interface *alts)
+{
+	switch (snd_usb_get_speed(chip->dev)) {
+	case USB_SPEED_HIGH:
+	case USB_SPEED_SUPER:
+	case USB_SPEED_SUPER_PLUS:
+		if (get_endpoint(alts, 0)->bInterval >= 1 &&
+		    get_endpoint(alts, 0)->bInterval <= 4)
+			return get_endpoint(alts, 0)->bInterval - 1;
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+struct usb_host_interface *
+snd_usb_get_host_interface(struct snd_usb_audio *chip, int ifnum, int altsetting)
+{
+	struct usb_interface *iface;
+
+	iface = usb_ifnum_to_if(chip->dev, ifnum);
+	if (!iface)
+		return NULL;
+	return usb_altnum_to_altsetting(iface, altsetting);
+}
+
+int snd_usb_add_ctrl_interface_link(struct snd_usb_audio *chip, int ifnum,
+		int ctrlif)
+{
+	struct usb_device *dev = chip->dev;
+	struct usb_host_interface *host_iface;
+
+	if (chip->num_intf_to_ctrl >= MAX_CARD_INTERFACES) {
+		dev_info(&dev->dev, "Too many interfaces assigned to the single USB-audio card\n");
+		return -EINVAL;
+	}
+
+	/* find audiocontrol interface */
+	host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
+
+	chip->intf_to_ctrl[chip->num_intf_to_ctrl].interface = ifnum;
+	chip->intf_to_ctrl[chip->num_intf_to_ctrl].ctrl_intf = host_iface;
+	chip->num_intf_to_ctrl++;
+
+	return 0;
+}
+
+struct usb_host_interface *snd_usb_find_ctrl_interface(struct snd_usb_audio *chip,
+							int ifnum)
+{
+	int i;
+
+	for (i = 0; i < chip->num_intf_to_ctrl; ++i)
+		if (chip->intf_to_ctrl[i].interface == ifnum)
+			return chip->intf_to_ctrl[i].ctrl_intf;
+
+	/* Fallback to first audiocontrol interface */
+	return chip->ctrl_intf;
+}
diff --git a/sound/usb/helper.h b/sound/usb/helper.h
new file mode 100644
index 000000000..0372e050b
--- /dev/null
+++ b/sound/usb/helper.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_HELPER_H
+#define __USBAUDIO_HELPER_H
+
+unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size);
+
+void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype);
+void *snd_usb_find_csint_desc(void *descstart, int desclen, void *after, u8 dsubtype);
+
+int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe,
+		    __u8 request, __u8 requesttype, __u16 value, __u16 index,
+		    void *data, __u16 size);
+
+unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
+					 struct usb_host_interface *alts);
+
+struct usb_host_interface *
+snd_usb_get_host_interface(struct snd_usb_audio *chip, int ifnum, int altsetting);
+
+int snd_usb_add_ctrl_interface_link(struct snd_usb_audio *chip, int ifnum,
+		int ctrlif);
+
+struct usb_host_interface *snd_usb_find_ctrl_interface(struct snd_usb_audio *chip,
+								int ifnum);
+
+/*
+ * retrieve usb_interface descriptor from the host interface
+ * (conditional for compatibility with the older API)
+ */
+#define get_iface_desc(iface)	(&(iface)->desc)
+#define get_endpoint(alt,ep)	(&(alt)->endpoint[ep].desc)
+#define get_ep_desc(ep)		(&(ep)->desc)
+#define get_cfg_desc(cfg)	(&(cfg)->desc)
+
+#define snd_usb_get_speed(dev) ((dev)->speed)
+
+static inline int snd_usb_ctrl_intf(struct usb_host_interface *ctrl_intf)
+{
+	return get_iface_desc(ctrl_intf)->bInterfaceNumber;
+}
+
+/* in validate.c */
+bool snd_usb_validate_audio_desc(void *p, int protocol);
+bool snd_usb_validate_midi_desc(void *p);
+
+#endif /* __USBAUDIO_HELPER_H */
diff --git a/sound/usb/hiface/Makefile b/sound/usb/hiface/Makefile
new file mode 100644
index 000000000..997c1558d
--- /dev/null
+++ b/sound/usb/hiface/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+snd-usb-hiface-y := chip.o pcm.o
+obj-$(CONFIG_SND_USB_HIFACE) += snd-usb-hiface.o
diff --git a/sound/usb/hiface/chip.c b/sound/usb/hiface/chip.c
new file mode 100644
index 000000000..bce28f683
--- /dev/null
+++ b/sound/usb/hiface/chip.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux driver for M2Tech hiFace compatible devices
+ *
+ * Copyright 2012-2013 (C) M2TECH S.r.l and Amarula Solutions B.V.
+ *
+ * Authors:  Michael Trimarchi <michael@amarulasolutions.com>
+ *           Antonio Ospite <ao2@amarulasolutions.com>
+ *
+ * The driver is based on the work done in TerraTec DMX 6Fire USB
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <sound/initval.h>
+
+#include "chip.h"
+#include "pcm.h"
+
+MODULE_AUTHOR("Michael Trimarchi <michael@amarulasolutions.com>");
+MODULE_AUTHOR("Antonio Ospite <ao2@amarulasolutions.com>");
+MODULE_DESCRIPTION("M2Tech hiFace USB-SPDIF audio driver");
+MODULE_LICENSE("GPL v2");
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-max */
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* Id for card */
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP; /* Enable this card */
+
+#define DRIVER_NAME "snd-usb-hiface"
+#define CARD_NAME "hiFace"
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "Index value for " CARD_NAME " soundcard.");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string for " CARD_NAME " soundcard.");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "Enable " CARD_NAME " soundcard.");
+
+static DEFINE_MUTEX(register_mutex);
+
+struct hiface_vendor_quirk {
+	const char *device_name;
+	u8 extra_freq;
+};
+
+static int hiface_chip_create(struct usb_interface *intf,
+			      struct usb_device *device, int idx,
+			      const struct hiface_vendor_quirk *quirk,
+			      struct hiface_chip **rchip)
+{
+	struct snd_card *card = NULL;
+	struct hiface_chip *chip;
+	int ret;
+	int len;
+
+	*rchip = NULL;
+
+	/* if we are here, card can be registered in alsa. */
+	ret = snd_card_new(&intf->dev, index[idx], id[idx], THIS_MODULE,
+			   sizeof(*chip), &card);
+	if (ret < 0) {
+		dev_err(&device->dev, "cannot create alsa card.\n");
+		return ret;
+	}
+
+	strscpy(card->driver, DRIVER_NAME, sizeof(card->driver));
+
+	if (quirk && quirk->device_name)
+		strscpy(card->shortname, quirk->device_name, sizeof(card->shortname));
+	else
+		strscpy(card->shortname, "M2Tech generic audio", sizeof(card->shortname));
+
+	strlcat(card->longname, card->shortname, sizeof(card->longname));
+	len = strlcat(card->longname, " at ", sizeof(card->longname));
+	if (len < sizeof(card->longname))
+		usb_make_path(device, card->longname + len,
+			      sizeof(card->longname) - len);
+
+	chip = card->private_data;
+	chip->dev = device;
+	chip->card = card;
+
+	*rchip = chip;
+	return 0;
+}
+
+static int hiface_chip_probe(struct usb_interface *intf,
+			     const struct usb_device_id *usb_id)
+{
+	const struct hiface_vendor_quirk *quirk = (struct hiface_vendor_quirk *)usb_id->driver_info;
+	int ret;
+	int i;
+	struct hiface_chip *chip;
+	struct usb_device *device = interface_to_usbdev(intf);
+
+	ret = usb_set_interface(device, 0, 0);
+	if (ret != 0) {
+		dev_err(&device->dev, "can't set first interface for " CARD_NAME " device.\n");
+		return -EIO;
+	}
+
+	/* check whether the card is already registered */
+	chip = NULL;
+	guard(mutex)(&register_mutex);
+
+	for (i = 0; i < SNDRV_CARDS; i++)
+		if (enable[i])
+			break;
+
+	if (i >= SNDRV_CARDS) {
+		dev_err(&device->dev, "no available " CARD_NAME " audio device\n");
+		return -ENODEV;
+	}
+
+	ret = hiface_chip_create(intf, device, i, quirk, &chip);
+	if (ret < 0)
+		return ret;
+
+	ret = hiface_pcm_init(chip, quirk ? quirk->extra_freq : 0);
+	if (ret < 0)
+		goto err_chip_destroy;
+
+	ret = snd_card_register(chip->card);
+	if (ret < 0) {
+		dev_err(&device->dev, "cannot register " CARD_NAME " card\n");
+		goto err_chip_destroy;
+	}
+
+	usb_set_intfdata(intf, chip);
+	return 0;
+
+err_chip_destroy:
+	snd_card_free(chip->card);
+	return ret;
+}
+
+static void hiface_chip_disconnect(struct usb_interface *intf)
+{
+	struct hiface_chip *chip;
+	struct snd_card *card;
+
+	chip = usb_get_intfdata(intf);
+	if (!chip)
+		return;
+
+	card = chip->card;
+
+	/* Make sure that the userspace cannot create new request */
+	snd_card_disconnect(card);
+
+	hiface_pcm_abort(chip);
+	snd_card_free_when_closed(card);
+}
+
+static const struct usb_device_id device_table[] = {
+	{
+		USB_DEVICE(0x04b4, 0x0384),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Young",
+			.extra_freq = 1,
+		}
+	},
+	{
+		USB_DEVICE(0x04b4, 0x930b),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "hiFace",
+		}
+	},
+	{
+		USB_DEVICE(0x04b4, 0x931b),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "North Star",
+		}
+	},
+	{
+		USB_DEVICE(0x04b4, 0x931c),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "W4S Young",
+		}
+	},
+	{
+		USB_DEVICE(0x04b4, 0x931d),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Corrson",
+		}
+	},
+	{
+		USB_DEVICE(0x04b4, 0x931e),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "AUDIA",
+		}
+	},
+	{
+		USB_DEVICE(0x04b4, 0x931f),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "SL Audio",
+		}
+	},
+	{
+		USB_DEVICE(0x04b4, 0x9320),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Empirical",
+		}
+	},
+	{
+		USB_DEVICE(0x04b4, 0x9321),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Rockna",
+		}
+	},
+	{
+		USB_DEVICE(0x249c, 0x9001),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Pathos",
+		}
+	},
+	{
+		USB_DEVICE(0x249c, 0x9002),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Metronome",
+		}
+	},
+	{
+		USB_DEVICE(0x249c, 0x9006),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "CAD",
+		}
+	},
+	{
+		USB_DEVICE(0x249c, 0x9008),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Audio Esclusive",
+		}
+	},
+	{
+		USB_DEVICE(0x249c, 0x931c),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Rotel",
+		}
+	},
+	{
+		USB_DEVICE(0x249c, 0x932c),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Eeaudio",
+		}
+	},
+	{
+		USB_DEVICE(0x245f, 0x931c),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "CHORD",
+		}
+	},
+	{
+		USB_DEVICE(0x25c6, 0x9002),
+		.driver_info = (unsigned long)&(const struct hiface_vendor_quirk) {
+			.device_name = "Vitus",
+		}
+	},
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, device_table);
+
+static struct usb_driver hiface_usb_driver = {
+	.name = DRIVER_NAME,
+	.probe = hiface_chip_probe,
+	.disconnect = hiface_chip_disconnect,
+	.id_table = device_table,
+};
+
+module_usb_driver(hiface_usb_driver);
diff --git a/sound/usb/hiface/chip.h b/sound/usb/hiface/chip.h
new file mode 100644
index 000000000..eb7a5cfb4
--- /dev/null
+++ b/sound/usb/hiface/chip.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for M2Tech hiFace compatible devices
+ *
+ * Copyright 2012-2013 (C) M2TECH S.r.l and Amarula Solutions B.V.
+ *
+ * Authors:  Michael Trimarchi <michael@amarulasolutions.com>
+ *           Antonio Ospite <ao2@amarulasolutions.com>
+ *
+ * The driver is based on the work done in TerraTec DMX 6Fire USB
+ */
+
+#ifndef HIFACE_CHIP_H
+#define HIFACE_CHIP_H
+
+#include <linux/usb.h>
+#include <sound/core.h>
+
+struct pcm_runtime;
+
+struct hiface_chip {
+	struct usb_device *dev;
+	struct snd_card *card;
+	struct pcm_runtime *pcm;
+};
+#endif /* HIFACE_CHIP_H */
diff --git a/sound/usb/hiface/pcm.c b/sound/usb/hiface/pcm.c
new file mode 100644
index 000000000..3157952e4
--- /dev/null
+++ b/sound/usb/hiface/pcm.c
@@ -0,0 +1,596 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux driver for M2Tech hiFace compatible devices
+ *
+ * Copyright 2012-2013 (C) M2TECH S.r.l and Amarula Solutions B.V.
+ *
+ * Authors:  Michael Trimarchi <michael@amarulasolutions.com>
+ *           Antonio Ospite <ao2@amarulasolutions.com>
+ *
+ * The driver is based on the work done in TerraTec DMX 6Fire USB
+ */
+
+#include <linux/slab.h>
+#include <sound/pcm.h>
+
+#include "pcm.h"
+#include "chip.h"
+
+#define OUT_EP          0x2
+#define PCM_N_URBS      8
+#define PCM_PACKET_SIZE 4096
+#define PCM_BUFFER_SIZE (2 * PCM_N_URBS * PCM_PACKET_SIZE)
+
+struct pcm_urb {
+	struct hiface_chip *chip;
+
+	struct urb *instance;
+	struct usb_anchor submitted;
+	u8 *buffer;
+};
+
+struct pcm_substream {
+	spinlock_t lock;
+	struct snd_pcm_substream *instance;
+
+	bool active;
+	snd_pcm_uframes_t dma_off;    /* current position in alsa dma_area */
+	snd_pcm_uframes_t period_off; /* current position in current period */
+};
+
+enum { /* pcm streaming states */
+	STREAM_DISABLED, /* no pcm streaming */
+	STREAM_STARTING, /* pcm streaming requested, waiting to become ready */
+	STREAM_RUNNING,  /* pcm streaming running */
+	STREAM_STOPPING
+};
+
+struct pcm_runtime {
+	struct hiface_chip *chip;
+	struct snd_pcm *instance;
+
+	struct pcm_substream playback;
+	bool panic; /* if set driver won't do anymore pcm on device */
+
+	struct pcm_urb out_urbs[PCM_N_URBS];
+
+	struct mutex stream_mutex;
+	u8 stream_state; /* one of STREAM_XXX */
+	u8 extra_freq;
+	wait_queue_head_t stream_wait_queue;
+	bool stream_wait_cond;
+};
+
+static const unsigned int rates[] = { 44100, 48000, 88200, 96000, 176400, 192000,
+				      352800, 384000 };
+static const struct snd_pcm_hw_constraint_list constraints_extra_rates = {
+	.count = ARRAY_SIZE(rates),
+	.list = rates,
+	.mask = 0,
+};
+
+static const struct snd_pcm_hardware pcm_hw = {
+	.info = SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_BLOCK_TRANSFER |
+		SNDRV_PCM_INFO_PAUSE |
+		SNDRV_PCM_INFO_MMAP_VALID |
+		SNDRV_PCM_INFO_BATCH,
+
+	.formats = SNDRV_PCM_FMTBIT_S32_LE,
+
+	.rates = SNDRV_PCM_RATE_44100 |
+		SNDRV_PCM_RATE_48000 |
+		SNDRV_PCM_RATE_88200 |
+		SNDRV_PCM_RATE_96000 |
+		SNDRV_PCM_RATE_176400 |
+		SNDRV_PCM_RATE_192000,
+
+	.rate_min = 44100,
+	.rate_max = 192000, /* changes in hiface_pcm_open to support extra rates */
+	.channels_min = 2,
+	.channels_max = 2,
+	.buffer_bytes_max = PCM_BUFFER_SIZE,
+	.period_bytes_min = PCM_PACKET_SIZE,
+	.period_bytes_max = PCM_BUFFER_SIZE,
+	.periods_min = 2,
+	.periods_max = 1024
+};
+
+/* message values used to change the sample rate */
+#define HIFACE_SET_RATE_REQUEST 0xb0
+
+#define HIFACE_RATE_44100  0x43
+#define HIFACE_RATE_48000  0x4b
+#define HIFACE_RATE_88200  0x42
+#define HIFACE_RATE_96000  0x4a
+#define HIFACE_RATE_176400 0x40
+#define HIFACE_RATE_192000 0x48
+#define HIFACE_RATE_352800 0x58
+#define HIFACE_RATE_384000 0x68
+
+static int hiface_pcm_set_rate(struct pcm_runtime *rt, unsigned int rate)
+{
+	struct usb_device *device = rt->chip->dev;
+	u16 rate_value;
+	int ret;
+
+	/* We are already sure that the rate is supported here thanks to
+	 * ALSA constraints
+	 */
+	switch (rate) {
+	case 44100:
+		rate_value = HIFACE_RATE_44100;
+		break;
+	case 48000:
+		rate_value = HIFACE_RATE_48000;
+		break;
+	case 88200:
+		rate_value = HIFACE_RATE_88200;
+		break;
+	case 96000:
+		rate_value = HIFACE_RATE_96000;
+		break;
+	case 176400:
+		rate_value = HIFACE_RATE_176400;
+		break;
+	case 192000:
+		rate_value = HIFACE_RATE_192000;
+		break;
+	case 352800:
+		rate_value = HIFACE_RATE_352800;
+		break;
+	case 384000:
+		rate_value = HIFACE_RATE_384000;
+		break;
+	default:
+		dev_err(&device->dev, "Unsupported rate %d\n", rate);
+		return -EINVAL;
+	}
+
+	/*
+	 * USBIO: Vendor 0xb0(wValue=0x0043, wIndex=0x0000)
+	 * 43 b0 43 00 00 00 00 00
+	 * USBIO: Vendor 0xb0(wValue=0x004b, wIndex=0x0000)
+	 * 43 b0 4b 00 00 00 00 00
+	 * This control message doesn't have any ack from the
+	 * other side
+	 */
+	ret = usb_control_msg_send(device, 0,
+				   HIFACE_SET_RATE_REQUEST,
+				   USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+				   rate_value, 0, NULL, 0, 100, GFP_KERNEL);
+	if (ret)
+		dev_err(&device->dev, "Error setting samplerate %d.\n", rate);
+
+	return ret;
+}
+
+static struct pcm_substream *hiface_pcm_get_substream(struct snd_pcm_substream
+						      *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct device *device = &rt->chip->dev->dev;
+
+	if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		return &rt->playback;
+
+	dev_err(device, "Error getting pcm substream slot.\n");
+	return NULL;
+}
+
+/* call with stream_mutex locked */
+static void hiface_pcm_stream_stop(struct pcm_runtime *rt)
+{
+	int i, time;
+
+	if (rt->stream_state != STREAM_DISABLED) {
+		rt->stream_state = STREAM_STOPPING;
+
+		for (i = 0; i < PCM_N_URBS; i++) {
+			time = usb_wait_anchor_empty_timeout(
+					&rt->out_urbs[i].submitted, 100);
+			if (!time)
+				usb_kill_anchored_urbs(
+					&rt->out_urbs[i].submitted);
+			usb_kill_urb(rt->out_urbs[i].instance);
+		}
+
+		rt->stream_state = STREAM_DISABLED;
+	}
+}
+
+/* call with stream_mutex locked */
+static int hiface_pcm_stream_start(struct pcm_runtime *rt)
+{
+	int ret = 0;
+	int i;
+
+	if (rt->stream_state == STREAM_DISABLED) {
+
+		/* reset panic state when starting a new stream */
+		rt->panic = false;
+
+		/* submit our out urbs zero init */
+		rt->stream_state = STREAM_STARTING;
+		for (i = 0; i < PCM_N_URBS; i++) {
+			memset(rt->out_urbs[i].buffer, 0, PCM_PACKET_SIZE);
+			usb_anchor_urb(rt->out_urbs[i].instance,
+				       &rt->out_urbs[i].submitted);
+			ret = usb_submit_urb(rt->out_urbs[i].instance,
+					     GFP_ATOMIC);
+			if (ret) {
+				hiface_pcm_stream_stop(rt);
+				return ret;
+			}
+		}
+
+		/* wait for first out urb to return (sent in urb handler) */
+		wait_event_timeout(rt->stream_wait_queue, rt->stream_wait_cond,
+				   HZ);
+		if (rt->stream_wait_cond) {
+			struct device *device = &rt->chip->dev->dev;
+			dev_dbg(device, "%s: Stream is running wakeup event\n",
+				 __func__);
+			rt->stream_state = STREAM_RUNNING;
+		} else {
+			hiface_pcm_stream_stop(rt);
+			return -EIO;
+		}
+	}
+	return ret;
+}
+
+/* The hardware wants word-swapped 32-bit values */
+static void memcpy_swahw32(u8 *dest, u8 *src, unsigned int n)
+{
+	unsigned int i;
+
+	for (i = 0; i < n / 4; i++)
+		((u32 *)dest)[i] = swahw32(((u32 *)src)[i]);
+}
+
+/* call with substream locked */
+/* returns true if a period elapsed */
+static bool hiface_pcm_playback(struct pcm_substream *sub, struct pcm_urb *urb)
+{
+	struct snd_pcm_runtime *alsa_rt = sub->instance->runtime;
+	struct device *device = &urb->chip->dev->dev;
+	u8 *source;
+	unsigned int pcm_buffer_size;
+
+	WARN_ON(alsa_rt->format != SNDRV_PCM_FORMAT_S32_LE);
+
+	pcm_buffer_size = snd_pcm_lib_buffer_bytes(sub->instance);
+
+	if (sub->dma_off + PCM_PACKET_SIZE <= pcm_buffer_size) {
+		dev_dbg(device, "%s: (1) buffer_size %#x dma_offset %#x\n", __func__,
+			 (unsigned int) pcm_buffer_size,
+			 (unsigned int) sub->dma_off);
+
+		source = alsa_rt->dma_area + sub->dma_off;
+		memcpy_swahw32(urb->buffer, source, PCM_PACKET_SIZE);
+	} else {
+		/* wrap around at end of ring buffer */
+		unsigned int len;
+
+		dev_dbg(device, "%s: (2) buffer_size %#x dma_offset %#x\n", __func__,
+			 (unsigned int) pcm_buffer_size,
+			 (unsigned int) sub->dma_off);
+
+		len = pcm_buffer_size - sub->dma_off;
+
+		source = alsa_rt->dma_area + sub->dma_off;
+		memcpy_swahw32(urb->buffer, source, len);
+
+		source = alsa_rt->dma_area;
+		memcpy_swahw32(urb->buffer + len, source,
+			       PCM_PACKET_SIZE - len);
+	}
+	sub->dma_off += PCM_PACKET_SIZE;
+	if (sub->dma_off >= pcm_buffer_size)
+		sub->dma_off -= pcm_buffer_size;
+
+	sub->period_off += PCM_PACKET_SIZE;
+	if (sub->period_off >= alsa_rt->period_size) {
+		sub->period_off %= alsa_rt->period_size;
+		return true;
+	}
+	return false;
+}
+
+static void hiface_pcm_out_urb_handler(struct urb *usb_urb)
+{
+	struct pcm_urb *out_urb = usb_urb->context;
+	struct pcm_runtime *rt = out_urb->chip->pcm;
+	struct pcm_substream *sub;
+	bool do_period_elapsed = false;
+	int ret;
+
+	if (rt->panic || rt->stream_state == STREAM_STOPPING)
+		return;
+
+	if (unlikely(usb_urb->status == -ENOENT ||	/* unlinked */
+		     usb_urb->status == -ENODEV ||	/* device removed */
+		     usb_urb->status == -ECONNRESET ||	/* unlinked */
+		     usb_urb->status == -ESHUTDOWN)) {	/* device disabled */
+		goto out_fail;
+	}
+
+	if (rt->stream_state == STREAM_STARTING) {
+		rt->stream_wait_cond = true;
+		wake_up(&rt->stream_wait_queue);
+	}
+
+	/* now send our playback data (if a free out urb was found) */
+	sub = &rt->playback;
+	scoped_guard(spinlock_irqsave, &sub->lock) {
+		if (sub->active)
+			do_period_elapsed = hiface_pcm_playback(sub, out_urb);
+		else
+			memset(out_urb->buffer, 0, PCM_PACKET_SIZE);
+	}
+
+	if (do_period_elapsed)
+		snd_pcm_period_elapsed(sub->instance);
+
+	ret = usb_submit_urb(out_urb->instance, GFP_ATOMIC);
+	if (ret < 0)
+		goto out_fail;
+
+	return;
+
+out_fail:
+	rt->panic = true;
+}
+
+static int hiface_pcm_open(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = NULL;
+	struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
+	int ret;
+
+	if (rt->panic)
+		return -EPIPE;
+
+	guard(mutex)(&rt->stream_mutex);
+	alsa_rt->hw = pcm_hw;
+
+	if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		sub = &rt->playback;
+
+	if (!sub) {
+		struct device *device = &rt->chip->dev->dev;
+		dev_err(device, "Invalid stream type\n");
+		return -EINVAL;
+	}
+
+	if (rt->extra_freq) {
+		alsa_rt->hw.rates |= SNDRV_PCM_RATE_KNOT;
+		alsa_rt->hw.rate_max = 384000;
+
+		/* explicit constraints needed as we added SNDRV_PCM_RATE_KNOT */
+		ret = snd_pcm_hw_constraint_list(alsa_sub->runtime, 0,
+						 SNDRV_PCM_HW_PARAM_RATE,
+						 &constraints_extra_rates);
+		if (ret < 0)
+			return ret;
+	}
+
+	sub->instance = alsa_sub;
+	sub->active = false;
+	return 0;
+}
+
+static int hiface_pcm_close(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = hiface_pcm_get_substream(alsa_sub);
+
+	if (rt->panic)
+		return 0;
+
+	guard(mutex)(&rt->stream_mutex);
+	if (sub) {
+		hiface_pcm_stream_stop(rt);
+
+		/* deactivate substream */
+		guard(spinlock_irqsave)(&sub->lock);
+		sub->instance = NULL;
+		sub->active = false;
+	}
+	return 0;
+}
+
+static int hiface_pcm_prepare(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = hiface_pcm_get_substream(alsa_sub);
+	struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
+	int ret;
+
+	if (rt->panic)
+		return -EPIPE;
+	if (!sub)
+		return -ENODEV;
+
+	guard(mutex)(&rt->stream_mutex);
+
+	hiface_pcm_stream_stop(rt);
+
+	sub->dma_off = 0;
+	sub->period_off = 0;
+
+	if (rt->stream_state == STREAM_DISABLED) {
+
+		ret = hiface_pcm_set_rate(rt, alsa_rt->rate);
+		if (ret)
+			return ret;
+		ret = hiface_pcm_stream_start(rt);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+static int hiface_pcm_trigger(struct snd_pcm_substream *alsa_sub, int cmd)
+{
+	struct pcm_substream *sub = hiface_pcm_get_substream(alsa_sub);
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+
+	if (rt->panic)
+		return -EPIPE;
+	if (!sub)
+		return -ENODEV;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		scoped_guard(spinlock_irq, &sub->lock) {
+			sub->active = true;
+		}
+		return 0;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		scoped_guard(spinlock_irq, &sub->lock) {
+			sub->active = false;
+		}
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static snd_pcm_uframes_t hiface_pcm_pointer(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_substream *sub = hiface_pcm_get_substream(alsa_sub);
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	snd_pcm_uframes_t dma_offset;
+
+	if (rt->panic || !sub)
+		return SNDRV_PCM_POS_XRUN;
+
+	guard(spinlock_irqsave)(&sub->lock);
+	dma_offset = sub->dma_off;
+	return bytes_to_frames(alsa_sub->runtime, dma_offset);
+}
+
+static const struct snd_pcm_ops pcm_ops = {
+	.open = hiface_pcm_open,
+	.close = hiface_pcm_close,
+	.prepare = hiface_pcm_prepare,
+	.trigger = hiface_pcm_trigger,
+	.pointer = hiface_pcm_pointer,
+};
+
+static int hiface_pcm_init_urb(struct pcm_urb *urb,
+			       struct hiface_chip *chip,
+			       unsigned int ep,
+			       void (*handler)(struct urb *))
+{
+	urb->chip = chip;
+	urb->instance = usb_alloc_urb(0, GFP_KERNEL);
+	if (!urb->instance)
+		return -ENOMEM;
+
+	urb->buffer = kzalloc(PCM_PACKET_SIZE, GFP_KERNEL);
+	if (!urb->buffer)
+		return -ENOMEM;
+
+	usb_fill_bulk_urb(urb->instance, chip->dev,
+			  usb_sndbulkpipe(chip->dev, ep), (void *)urb->buffer,
+			  PCM_PACKET_SIZE, handler, urb);
+	if (usb_urb_ep_type_check(urb->instance))
+		return -EINVAL;
+	init_usb_anchor(&urb->submitted);
+
+	return 0;
+}
+
+void hiface_pcm_abort(struct hiface_chip *chip)
+{
+	struct pcm_runtime *rt = chip->pcm;
+
+	if (rt) {
+		rt->panic = true;
+
+		guard(mutex)(&rt->stream_mutex);
+		hiface_pcm_stream_stop(rt);
+	}
+}
+
+static void hiface_pcm_destroy(struct pcm_runtime *rt)
+{
+	int i;
+
+	if (!rt)
+		return;
+
+	if (rt->chip)
+		rt->chip->pcm = NULL;
+
+	for (i = 0; i < PCM_N_URBS; i++) {
+		usb_free_urb(rt->out_urbs[i].instance);
+		kfree(rt->out_urbs[i].buffer);
+	}
+	kfree(rt);
+}
+
+static void hiface_pcm_free(struct snd_pcm *pcm)
+{
+	hiface_pcm_destroy(pcm->private_data);
+}
+
+int hiface_pcm_init(struct hiface_chip *chip, u8 extra_freq)
+{
+	int i;
+	int ret;
+	struct snd_pcm *pcm;
+	struct pcm_runtime *rt;
+
+	rt = kzalloc_obj(*rt);
+	if (!rt)
+		return -ENOMEM;
+
+	rt->chip = chip;
+	rt->stream_state = STREAM_DISABLED;
+	if (extra_freq)
+		rt->extra_freq = 1;
+
+	init_waitqueue_head(&rt->stream_wait_queue);
+	mutex_init(&rt->stream_mutex);
+	spin_lock_init(&rt->playback.lock);
+
+	for (i = 0; i < PCM_N_URBS; i++) {
+		ret = hiface_pcm_init_urb(&rt->out_urbs[i], chip, OUT_EP,
+				    hiface_pcm_out_urb_handler);
+		if (ret < 0)
+			goto error;
+	}
+
+	ret = snd_pcm_new(chip->card, "USB-SPDIF Audio", 0, 1, 0, &pcm);
+	if (ret < 0) {
+		dev_err(&chip->dev->dev, "Cannot create pcm instance\n");
+		goto error;
+	}
+
+	pcm->private_data = rt;
+	pcm->private_free = hiface_pcm_free;
+
+	strscpy(pcm->name, "USB-SPDIF Audio", sizeof(pcm->name));
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_ops);
+	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC,
+				       NULL, 0, 0);
+
+	rt->instance = pcm;
+
+	chip->pcm = rt;
+	return 0;
+
+error:
+	hiface_pcm_destroy(rt);
+	return ret;
+}
diff --git a/sound/usb/hiface/pcm.h b/sound/usb/hiface/pcm.h
new file mode 100644
index 000000000..afe74e978
--- /dev/null
+++ b/sound/usb/hiface/pcm.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Linux driver for M2Tech hiFace compatible devices
+ *
+ * Copyright 2012-2013 (C) M2TECH S.r.l and Amarula Solutions B.V.
+ *
+ * Authors:  Michael Trimarchi <michael@amarulasolutions.com>
+ *           Antonio Ospite <ao2@amarulasolutions.com>
+ *
+ * The driver is based on the work done in TerraTec DMX 6Fire USB
+ */
+
+#ifndef HIFACE_PCM_H
+#define HIFACE_PCM_H
+
+struct hiface_chip;
+
+int hiface_pcm_init(struct hiface_chip *chip, u8 extra_freq);
+void hiface_pcm_abort(struct hiface_chip *chip);
+#endif /* HIFACE_PCM_H */
diff --git a/sound/usb/implicit.c b/sound/usb/implicit.c
new file mode 100644
index 000000000..bd4d569a8
--- /dev/null
+++ b/sound/usb/implicit.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// Special handling for implicit feedback mode
+//
+
+#include <linux/init.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "helper.h"
+#include "pcm.h"
+#include "implicit.h"
+
+enum {
+	IMPLICIT_FB_NONE,
+	IMPLICIT_FB_GENERIC,
+	IMPLICIT_FB_FIXED,
+	IMPLICIT_FB_BOTH,	/* generic playback + capture (for BOSS) */
+};
+
+struct snd_usb_implicit_fb_match {
+	unsigned int id;
+	unsigned int iface_class;
+	unsigned int ep_num;
+	unsigned int iface;
+	int type;
+};
+
+#define IMPLICIT_FB_GENERIC_DEV(vend, prod) \
+	{ .id = USB_ID(vend, prod), .type = IMPLICIT_FB_GENERIC }
+#define IMPLICIT_FB_FIXED_DEV(vend, prod, ep, ifnum) \
+	{ .id = USB_ID(vend, prod), .type = IMPLICIT_FB_FIXED, .ep_num = (ep),\
+	    .iface = (ifnum) }
+#define IMPLICIT_FB_BOTH_DEV(vend, prod, ep, ifnum) \
+	{ .id = USB_ID(vend, prod), .type = IMPLICIT_FB_BOTH, .ep_num = (ep),\
+	    .iface = (ifnum) }
+#define IMPLICIT_FB_SKIP_DEV(vend, prod) \
+	{ .id = USB_ID(vend, prod), .type = IMPLICIT_FB_NONE }
+
+/* Implicit feedback quirk table for playback */
+static const struct snd_usb_implicit_fb_match playback_implicit_fb_quirks[] = {
+	/* Fixed EP */
+	/* FIXME: check the availability of generic matching */
+	IMPLICIT_FB_FIXED_DEV(0x0763, 0x2030, 0x81, 3), /* M-Audio Fast Track C400 */
+	IMPLICIT_FB_FIXED_DEV(0x0763, 0x2031, 0x81, 3), /* M-Audio Fast Track C600 */
+	IMPLICIT_FB_FIXED_DEV(0x0763, 0x2080, 0x81, 2), /* M-Audio FastTrack Ultra */
+	IMPLICIT_FB_FIXED_DEV(0x0763, 0x2081, 0x81, 2), /* M-Audio FastTrack Ultra */
+	IMPLICIT_FB_FIXED_DEV(0x2466, 0x8010, 0x81, 2), /* Fractal Audio Axe-Fx III */
+	IMPLICIT_FB_FIXED_DEV(0x31e9, 0x0001, 0x81, 2), /* Solid State Logic SSL2 */
+	IMPLICIT_FB_FIXED_DEV(0x31e9, 0x0002, 0x81, 2), /* Solid State Logic SSL2+ */
+	IMPLICIT_FB_FIXED_DEV(0x0499, 0x172f, 0x81, 2), /* Steinberg UR22C */
+	IMPLICIT_FB_FIXED_DEV(0x0d9a, 0x00df, 0x81, 2), /* RTX6001 */
+	IMPLICIT_FB_FIXED_DEV(0x19f7, 0x000a, 0x84, 3), /* RODE AI-1 */
+	IMPLICIT_FB_FIXED_DEV(0x22f0, 0x0006, 0x81, 3), /* Allen&Heath Qu-16 */
+	IMPLICIT_FB_FIXED_DEV(0x1686, 0xf029, 0x82, 2), /* Zoom UAC-2 */
+	IMPLICIT_FB_FIXED_DEV(0x2466, 0x8003, 0x86, 2), /* Fractal Audio Axe-Fx II */
+	IMPLICIT_FB_FIXED_DEV(0x0499, 0x172a, 0x86, 2), /* Yamaha MODX */
+
+	/* Special matching */
+	{ .id = USB_ID(0x07fd, 0x0004), .iface_class = USB_CLASS_AUDIO,
+	  .type = IMPLICIT_FB_NONE },		/* MicroBook IIc */
+	/* ep = 0x84, ifnum = 0 */
+	{ .id = USB_ID(0x07fd, 0x0004), .iface_class = USB_CLASS_VENDOR_SPEC,
+	  .type = IMPLICIT_FB_FIXED,
+	  .ep_num = 0x84, .iface = 0 },		/* MOTU MicroBook II */
+
+	{} /* terminator */
+};
+
+/* Implicit feedback quirk table for capture: only FIXED type */
+static const struct snd_usb_implicit_fb_match capture_implicit_fb_quirks[] = {
+	IMPLICIT_FB_FIXED_DEV(0x1397, 0x0004, 0x01, 1), /* Behringer FCA1616 */
+	{} /* terminator */
+};
+
+/* set up sync EP information on the audioformat */
+static int add_implicit_fb_sync_ep(struct snd_usb_audio *chip,
+				   struct audioformat *fmt,
+				   int ep, int ep_idx, int ifnum,
+				   const struct usb_host_interface *alts)
+{
+	struct usb_interface *iface;
+
+	if (!alts) {
+		iface = usb_ifnum_to_if(chip->dev, ifnum);
+		if (!iface || iface->num_altsetting < 2)
+			return 0;
+		alts = &iface->altsetting[1];
+	}
+
+	fmt->sync_ep = ep;
+	fmt->sync_iface = ifnum;
+	fmt->sync_altsetting = alts->desc.bAlternateSetting;
+	fmt->sync_ep_idx = ep_idx;
+	fmt->implicit_fb = 1;
+	usb_audio_dbg(chip,
+		      "%d:%d: added %s implicit_fb sync_ep %x, iface %d:%d\n",
+		      fmt->iface, fmt->altsetting,
+		      (ep & USB_DIR_IN) ? "playback" : "capture",
+		      fmt->sync_ep, fmt->sync_iface, fmt->sync_altsetting);
+	return 1;
+}
+
+/* Check whether the given UAC2 iface:altset points to an implicit fb source */
+static int add_generic_uac2_implicit_fb(struct snd_usb_audio *chip,
+					struct audioformat *fmt,
+					unsigned int ifnum,
+					unsigned int altsetting)
+{
+	struct usb_host_interface *alts;
+	struct usb_endpoint_descriptor *epd;
+
+	alts = snd_usb_get_host_interface(chip, ifnum, altsetting);
+	if (!alts)
+		return 0;
+	if (alts->desc.bInterfaceClass != USB_CLASS_AUDIO ||
+	    alts->desc.bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING ||
+	    alts->desc.bInterfaceProtocol != UAC_VERSION_2 ||
+	    alts->desc.bNumEndpoints < 1)
+		return 0;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_in(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_USAGE_MASK) !=
+					USB_ENDPOINT_USAGE_IMPLICIT_FB)
+		return 0;
+	return add_implicit_fb_sync_ep(chip, fmt, epd->bEndpointAddress, 0,
+				       ifnum, alts);
+}
+
+static bool roland_sanity_check_iface(struct usb_host_interface *alts)
+{
+	if (alts->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC ||
+	    (alts->desc.bInterfaceSubClass != 2 &&
+	     alts->desc.bInterfaceProtocol != 2) ||
+	    alts->desc.bNumEndpoints < 1)
+		return false;
+	return true;
+}
+
+/* Like the UAC2 case above, but specific to Roland with vendor class and hack */
+static int add_roland_implicit_fb(struct snd_usb_audio *chip,
+				  struct audioformat *fmt,
+				  struct usb_host_interface *alts)
+{
+	struct usb_endpoint_descriptor *epd;
+
+	if (!roland_sanity_check_iface(alts))
+		return 0;
+	/* only when both streams are with ASYNC type */
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_out(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
+		return 0;
+
+	/* check capture EP */
+	alts = snd_usb_get_host_interface(chip,
+					  alts->desc.bInterfaceNumber + 1,
+					  alts->desc.bAlternateSetting);
+	if (!alts || !roland_sanity_check_iface(alts))
+		return 0;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_in(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
+		return 0;
+	chip->quirk_flags |= QUIRK_FLAG_PLAYBACK_FIRST;
+	return add_implicit_fb_sync_ep(chip, fmt, epd->bEndpointAddress, 0,
+				       alts->desc.bInterfaceNumber, alts);
+}
+
+/* capture quirk for Roland device; always full-duplex */
+static int add_roland_capture_quirk(struct snd_usb_audio *chip,
+				    struct audioformat *fmt,
+				    struct usb_host_interface *alts)
+{
+	struct usb_endpoint_descriptor *epd;
+
+	if (!roland_sanity_check_iface(alts))
+		return 0;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_in(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
+		return 0;
+
+	alts = snd_usb_get_host_interface(chip,
+					  alts->desc.bInterfaceNumber - 1,
+					  alts->desc.bAlternateSetting);
+	if (!alts || !roland_sanity_check_iface(alts))
+		return 0;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_out(epd))
+		return 0;
+	return add_implicit_fb_sync_ep(chip, fmt, epd->bEndpointAddress, 0,
+				       alts->desc.bInterfaceNumber, alts);
+}
+
+/* Playback and capture EPs on Pioneer devices share the same iface/altset
+ * for the implicit feedback operation
+ */
+static bool is_pioneer_implicit_fb(struct snd_usb_audio *chip,
+				   struct usb_host_interface *alts)
+
+{
+	struct usb_endpoint_descriptor *epd;
+
+	if (USB_ID_VENDOR(chip->usb_id) != 0x2b73 &&
+	    USB_ID_VENDOR(chip->usb_id) != 0x08e4)
+		return false;
+	if (alts->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC)
+		return false;
+	if (alts->desc.bNumEndpoints != 2)
+		return false;
+
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_out(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
+		return false;
+
+	epd = get_endpoint(alts, 1);
+	if (!usb_endpoint_is_isoc_in(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC ||
+	    ((epd->bmAttributes & USB_ENDPOINT_USAGE_MASK) !=
+	     USB_ENDPOINT_USAGE_DATA &&
+	     (epd->bmAttributes & USB_ENDPOINT_USAGE_MASK) !=
+	     USB_ENDPOINT_USAGE_IMPLICIT_FB))
+		return false;
+
+	return true;
+}
+
+static int __add_generic_implicit_fb(struct snd_usb_audio *chip,
+				     struct audioformat *fmt,
+				     int iface, int altset)
+{
+	struct usb_host_interface *alts;
+	struct usb_endpoint_descriptor *epd;
+
+	alts = snd_usb_get_host_interface(chip, iface, altset);
+	if (!alts)
+		return 0;
+
+	if ((alts->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC &&
+	     alts->desc.bInterfaceClass != USB_CLASS_AUDIO) ||
+	    alts->desc.bNumEndpoints < 1)
+		return 0;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_is_isoc_in(epd) ||
+	    (epd->bmAttributes & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
+		return 0;
+	return add_implicit_fb_sync_ep(chip, fmt, epd->bEndpointAddress, 0,
+				       iface, alts);
+}
+
+/* More generic quirk: look for the sync EP next to the data EP */
+static int add_generic_implicit_fb(struct snd_usb_audio *chip,
+				   struct audioformat *fmt,
+				   struct usb_host_interface *alts)
+{
+	if ((fmt->ep_attr & USB_ENDPOINT_SYNCTYPE) != USB_ENDPOINT_SYNC_ASYNC)
+		return 0;
+
+	if (__add_generic_implicit_fb(chip, fmt,
+				      alts->desc.bInterfaceNumber + 1,
+				      alts->desc.bAlternateSetting))
+		return 1;
+	return __add_generic_implicit_fb(chip, fmt,
+					 alts->desc.bInterfaceNumber - 1,
+					 alts->desc.bAlternateSetting);
+}
+
+static const struct snd_usb_implicit_fb_match *
+find_implicit_fb_entry(struct snd_usb_audio *chip,
+		       const struct snd_usb_implicit_fb_match *match,
+		       const struct usb_host_interface *alts)
+{
+	for (; match->id; match++)
+		if (match->id == chip->usb_id &&
+		    (!match->iface_class ||
+		     (alts->desc.bInterfaceClass == match->iface_class)))
+			return match;
+
+	return NULL;
+}
+
+/* Setup an implicit feedback endpoint from a quirk. Returns 0 if no quirk
+ * applies. Returns 1 if a quirk was found.
+ */
+static int audioformat_implicit_fb_quirk(struct snd_usb_audio *chip,
+					 struct audioformat *fmt,
+					 struct usb_host_interface *alts)
+{
+	const struct snd_usb_implicit_fb_match *p;
+	unsigned int attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
+
+	p = find_implicit_fb_entry(chip, playback_implicit_fb_quirks, alts);
+	if (p) {
+		switch (p->type) {
+		case IMPLICIT_FB_GENERIC:
+			return add_generic_implicit_fb(chip, fmt, alts);
+		case IMPLICIT_FB_NONE:
+			return 0; /* No quirk */
+		case IMPLICIT_FB_FIXED:
+			return add_implicit_fb_sync_ep(chip, fmt, p->ep_num, 0,
+						       p->iface, NULL);
+		}
+	}
+
+	/* Special handling for devices with capture quirks */
+	p = find_implicit_fb_entry(chip, capture_implicit_fb_quirks, alts);
+	if (p) {
+		switch (p->type) {
+		case IMPLICIT_FB_FIXED:
+			return 0; /* no quirk */
+		case IMPLICIT_FB_BOTH:
+			chip->quirk_flags |= QUIRK_FLAG_PLAYBACK_FIRST;
+			return add_generic_implicit_fb(chip, fmt, alts);
+		}
+	}
+
+	/* Generic UAC2 implicit feedback */
+	if (attr == USB_ENDPOINT_SYNC_ASYNC &&
+	    alts->desc.bInterfaceClass == USB_CLASS_AUDIO &&
+	    alts->desc.bInterfaceProtocol == UAC_VERSION_2 &&
+	    alts->desc.bNumEndpoints == 1) {
+		if (add_generic_uac2_implicit_fb(chip, fmt,
+						 alts->desc.bInterfaceNumber + 1,
+						 alts->desc.bAlternateSetting))
+			return 1;
+	}
+
+	/* Roland/BOSS implicit feedback with vendor spec class */
+	if (USB_ID_VENDOR(chip->usb_id) == 0x0582) {
+		if (add_roland_implicit_fb(chip, fmt, alts) > 0)
+			return 1;
+	}
+
+	/* Pioneer devices with vendor spec class */
+	if (is_pioneer_implicit_fb(chip, alts)) {
+		chip->quirk_flags |= QUIRK_FLAG_PLAYBACK_FIRST;
+		return add_implicit_fb_sync_ep(chip, fmt,
+					       get_endpoint(alts, 1)->bEndpointAddress,
+					       1, alts->desc.bInterfaceNumber,
+					       alts);
+	}
+
+	/* Try the generic implicit fb if available */
+	if (chip->generic_implicit_fb ||
+	    (chip->quirk_flags & QUIRK_FLAG_GENERIC_IMPLICIT_FB))
+		return add_generic_implicit_fb(chip, fmt, alts);
+
+	/* No quirk */
+	return 0;
+}
+
+/* same for capture, but only handling FIXED entry */
+static int audioformat_capture_quirk(struct snd_usb_audio *chip,
+				     struct audioformat *fmt,
+				     struct usb_host_interface *alts)
+{
+	const struct snd_usb_implicit_fb_match *p;
+
+	p = find_implicit_fb_entry(chip, capture_implicit_fb_quirks, alts);
+	if (p && (p->type == IMPLICIT_FB_FIXED || p->type == IMPLICIT_FB_BOTH))
+		return add_implicit_fb_sync_ep(chip, fmt, p->ep_num, 0,
+					       p->iface, NULL);
+
+	/* Roland/BOSS need full-duplex streams */
+	if (USB_ID_VENDOR(chip->usb_id) == 0x0582) {
+		if (add_roland_capture_quirk(chip, fmt, alts) > 0)
+			return 1;
+	}
+
+	if (is_pioneer_implicit_fb(chip, alts))
+		return 1; /* skip the quirk, also don't handle generic sync EP */
+	return 0;
+}
+
+/*
+ * Parse altset and set up implicit feedback endpoint on the audioformat
+ */
+int snd_usb_parse_implicit_fb_quirk(struct snd_usb_audio *chip,
+				    struct audioformat *fmt,
+				    struct usb_host_interface *alts)
+{
+	if (chip->quirk_flags & QUIRK_FLAG_SKIP_IMPLICIT_FB)
+		return 0;
+	if (fmt->endpoint & USB_DIR_IN)
+		return audioformat_capture_quirk(chip, fmt, alts);
+	else
+		return audioformat_implicit_fb_quirk(chip, fmt, alts);
+}
+
+/*
+ * Return the score of matching two audioformats.
+ * Veto the audioformat if:
+ * - It has no channels for some reason.
+ * - Requested PCM format is not supported.
+ * - Requested sample rate is not supported.
+ */
+static int match_endpoint_audioformats(struct snd_usb_substream *subs,
+				       const struct audioformat *fp,
+				       int rate, int channels,
+				       snd_pcm_format_t pcm_format)
+{
+	int i, score;
+
+	if (fp->channels < 1)
+		return 0;
+
+	if (!(fp->formats & pcm_format_to_bits(pcm_format)))
+		return 0;
+
+	if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS) {
+		if (rate < fp->rate_min || rate > fp->rate_max)
+			return 0;
+	} else {
+		for (i = 0; i < fp->nr_rates; i++) {
+			if (fp->rate_table[i] == rate)
+				break;
+		}
+		if (i >= fp->nr_rates)
+			return 0;
+	}
+
+	score = 1;
+	if (fp->channels == channels)
+		score++;
+
+	return score;
+}
+
+static struct snd_usb_substream *
+find_matching_substream(struct snd_usb_audio *chip, int stream, int ep_num,
+			int fmt_type)
+{
+	struct snd_usb_stream *as;
+	struct snd_usb_substream *subs;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		subs = &as->substream[stream];
+		if (as->fmt_type == fmt_type && subs->ep_num == ep_num)
+			return subs;
+	}
+
+	return NULL;
+}
+
+/*
+ * Return the audioformat that is suitable for the implicit fb
+ */
+const struct audioformat *
+snd_usb_find_implicit_fb_sync_format(struct snd_usb_audio *chip,
+				     const struct audioformat *target,
+				     const struct snd_pcm_hw_params *params,
+				     int stream,
+				     bool *fixed_rate)
+{
+	struct snd_usb_substream *subs;
+	const struct audioformat *fp, *sync_fmt = NULL;
+	int score, high_score;
+
+	/* Use the original audioformat as fallback for the shared altset */
+	if (target->iface == target->sync_iface &&
+	    target->altsetting == target->sync_altsetting)
+		sync_fmt = target;
+
+	subs = find_matching_substream(chip, stream, target->sync_ep,
+				       target->fmt_type);
+	if (!subs)
+		goto end;
+
+	high_score = 0;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		score = match_endpoint_audioformats(subs, fp,
+						    params_rate(params),
+						    params_channels(params),
+						    params_format(params));
+		if (score > high_score) {
+			sync_fmt = fp;
+			high_score = score;
+		}
+	}
+
+ end:
+	if (fixed_rate)
+		*fixed_rate = snd_usb_pcm_has_fixed_rate(subs);
+	return sync_fmt;
+}
+
diff --git a/sound/usb/implicit.h b/sound/usb/implicit.h
new file mode 100644
index 000000000..7f1577b6c
--- /dev/null
+++ b/sound/usb/implicit.h
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef __USBAUDIO_IMPLICIT_H
+#define __USBAUDIO_IMPLICIT_H
+
+int snd_usb_parse_implicit_fb_quirk(struct snd_usb_audio *chip,
+				    struct audioformat *fmt,
+				    struct usb_host_interface *alts);
+const struct audioformat *
+snd_usb_find_implicit_fb_sync_format(struct snd_usb_audio *chip,
+				     const struct audioformat *target,
+				     const struct snd_pcm_hw_params *params,
+				     int stream, bool *fixed_rate);
+
+#endif /* __USBAUDIO_IMPLICIT_H */
diff --git a/sound/usb/line6/Kconfig b/sound/usb/line6/Kconfig
new file mode 100644
index 000000000..ab557e5ee
--- /dev/null
+++ b/sound/usb/line6/Kconfig
@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SND_USB_LINE6
+	tristate
+	select SND_RAWMIDI
+	select SND_PCM
+	select SND_HWDEP
+
+config SND_USB_POD
+	tristate "Line 6 POD USB support"
+	select SND_USB_LINE6
+	help
+	  This is a driver for PODxt and other similar devices,
+	  supporting the following features:
+	    * Reading/writing individual parameters
+	    * Reading/writing complete channel, effects setup, and amp
+	      setup data
+	    * Channel switching
+	    * Virtual MIDI interface
+	    * Tuner access
+	    * Playback/capture/mixer device for any ALSA-compatible PCM
+	      audio application
+	    * Signal routing (record clean/processed guitar signal,
+	      re-amping)
+
+config SND_USB_PODHD
+	tristate "Line 6 POD X3/HD300/400/500 USB support"
+	select SND_USB_LINE6
+	help
+	  This is a driver for POD X3, HD300, 400 and 500 devices.
+
+config SND_USB_TONEPORT
+	tristate "TonePort GX, UX1 and UX2 USB support"
+	select SND_USB_LINE6
+	select NEW_LEDS
+	select LEDS_CLASS
+	help
+	  This is a driver for TonePort GX, UX1 and UX2 devices.
+
+config SND_USB_VARIAX
+	tristate "Variax Workbench USB support"
+	select SND_USB_LINE6
+	help
+	  This is a driver for Variax Workbench device.
+
diff --git a/sound/usb/line6/Makefile b/sound/usb/line6/Makefile
new file mode 100644
index 000000000..4ba98eb32
--- /dev/null
+++ b/sound/usb/line6/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+snd-usb-line6-y := 		\
+		capture.o	\
+		driver.o	\
+		midi.o		\
+		midibuf.o	\
+		pcm.o		\
+		playback.o
+
+snd-usb-pod-y := pod.o
+snd-usb-podhd-y := podhd.o
+snd-usb-toneport-y := toneport.o
+snd-usb-variax-y := variax.o
+
+obj-$(CONFIG_SND_USB_LINE6)	+= snd-usb-line6.o
+obj-$(CONFIG_SND_USB_POD)	+= snd-usb-pod.o
+obj-$(CONFIG_SND_USB_PODHD)	+= snd-usb-podhd.o
+obj-$(CONFIG_SND_USB_TONEPORT)	+= snd-usb-toneport.o
+obj-$(CONFIG_SND_USB_VARIAX)	+= snd-usb-variax.o
diff --git a/sound/usb/line6/capture.c b/sound/usb/line6/capture.c
new file mode 100644
index 000000000..6dbaf3023
--- /dev/null
+++ b/sound/usb/line6/capture.c
@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include "capture.h"
+#include "driver.h"
+#include "pcm.h"
+
+/*
+	Find a free URB and submit it.
+	must be called in line6pcm->in.lock context
+*/
+static int submit_audio_in_urb(struct snd_line6_pcm *line6pcm)
+{
+	int index;
+	int i, urb_size;
+	int ret;
+	struct urb *urb_in;
+
+	index = find_first_zero_bit(&line6pcm->in.active_urbs,
+				    line6pcm->line6->iso_buffers);
+
+	if (index < 0 || index >= line6pcm->line6->iso_buffers) {
+		dev_err(line6pcm->line6->ifcdev, "no free URB found\n");
+		return -EINVAL;
+	}
+
+	urb_in = line6pcm->in.urbs[index];
+	urb_size = 0;
+
+	for (i = 0; i < LINE6_ISO_PACKETS; ++i) {
+		struct usb_iso_packet_descriptor *fin =
+		    &urb_in->iso_frame_desc[i];
+		fin->offset = urb_size;
+		fin->length = line6pcm->max_packet_size_in;
+		urb_size += line6pcm->max_packet_size_in;
+	}
+
+	urb_in->transfer_buffer =
+	    line6pcm->in.buffer +
+	    index * LINE6_ISO_PACKETS * line6pcm->max_packet_size_in;
+	urb_in->transfer_buffer_length = urb_size;
+	urb_in->context = line6pcm;
+
+	ret = usb_submit_urb(urb_in, GFP_ATOMIC);
+
+	if (ret == 0)
+		set_bit(index, &line6pcm->in.active_urbs);
+	else
+		dev_err(line6pcm->line6->ifcdev,
+			"URB in #%d submission failed (%d)\n", index, ret);
+
+	return 0;
+}
+
+/*
+	Submit all currently available capture URBs.
+	must be called in line6pcm->in.lock context
+*/
+int line6_submit_audio_in_all_urbs(struct snd_line6_pcm *line6pcm)
+{
+	int ret = 0, i;
+
+	for (i = 0; i < line6pcm->line6->iso_buffers; ++i) {
+		ret = submit_audio_in_urb(line6pcm);
+		if (ret < 0)
+			break;
+	}
+
+	return ret;
+}
+
+/*
+	Copy data into ALSA capture buffer.
+*/
+void line6_capture_copy(struct snd_line6_pcm *line6pcm, char *fbuf, int fsize)
+{
+	struct snd_pcm_substream *substream =
+	    get_substream(line6pcm, SNDRV_PCM_STREAM_CAPTURE);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	const int bytes_per_frame =
+		line6pcm->properties->bytes_per_channel *
+		line6pcm->properties->capture_hw.channels_max;
+	int frames = fsize / bytes_per_frame;
+
+	if (runtime == NULL)
+		return;
+
+	if (line6pcm->in.pos_done + frames > runtime->buffer_size) {
+		/*
+		   The transferred area goes over buffer boundary,
+		   copy two separate chunks.
+		 */
+		int len;
+
+		len = runtime->buffer_size - line6pcm->in.pos_done;
+
+		if (len > 0) {
+			memcpy(runtime->dma_area +
+			       line6pcm->in.pos_done * bytes_per_frame, fbuf,
+			       len * bytes_per_frame);
+			memcpy(runtime->dma_area, fbuf + len * bytes_per_frame,
+			       (frames - len) * bytes_per_frame);
+		} else {
+			/* this is somewhat paranoid */
+			dev_err(line6pcm->line6->ifcdev,
+				"driver bug: len = %d\n", len);
+		}
+	} else {
+		/* copy single chunk */
+		memcpy(runtime->dma_area +
+		       line6pcm->in.pos_done * bytes_per_frame, fbuf, fsize);
+	}
+
+	line6pcm->in.pos_done += frames;
+	if (line6pcm->in.pos_done >= runtime->buffer_size)
+		line6pcm->in.pos_done -= runtime->buffer_size;
+}
+
+void line6_capture_check_period(struct snd_line6_pcm *line6pcm, int length)
+{
+	struct snd_pcm_substream *substream =
+	    get_substream(line6pcm, SNDRV_PCM_STREAM_CAPTURE);
+
+	line6pcm->in.bytes += length;
+	if (line6pcm->in.bytes >= line6pcm->in.period) {
+		line6pcm->in.bytes %= line6pcm->in.period;
+		spin_unlock(&line6pcm->in.lock);
+		snd_pcm_period_elapsed(substream);
+		spin_lock(&line6pcm->in.lock);
+	}
+}
+
+/*
+ * Callback for completed capture URB.
+ */
+static void audio_in_callback(struct urb *urb)
+{
+	int i, index, length = 0, shutdown = 0;
+	struct snd_line6_pcm *line6pcm = (struct snd_line6_pcm *)urb->context;
+
+	line6pcm->in.last_frame = urb->start_frame;
+
+	/* find index of URB */
+	for (index = 0; index < line6pcm->line6->iso_buffers; ++index)
+		if (urb == line6pcm->in.urbs[index])
+			break;
+
+	guard(spinlock_irqsave)(&line6pcm->in.lock);
+
+	for (i = 0; i < LINE6_ISO_PACKETS; ++i) {
+		char *fbuf;
+		int fsize;
+		struct usb_iso_packet_descriptor *fin = &urb->iso_frame_desc[i];
+
+		if (fin->status == -EXDEV) {
+			shutdown = 1;
+			break;
+		}
+
+		fbuf = urb->transfer_buffer + fin->offset;
+		fsize = fin->actual_length;
+
+		if (fsize > line6pcm->max_packet_size_in) {
+			dev_err(line6pcm->line6->ifcdev,
+				"driver and/or device bug: packet too large (%d > %d)\n",
+				fsize, line6pcm->max_packet_size_in);
+		}
+
+		length += fsize;
+
+		BUILD_BUG_ON_MSG(LINE6_ISO_PACKETS != 1,
+			"The following code assumes LINE6_ISO_PACKETS == 1");
+		/* TODO:
+		 * Also, if iso_buffers != 2, the prev frame is almost random at
+		 * playback side.
+		 * This needs to be redesigned. It should be "stable", but we may
+		 * experience sync problems on such high-speed configs.
+		 */
+
+		line6pcm->prev_fbuf = fbuf;
+		line6pcm->prev_fsize = fsize /
+			(line6pcm->properties->bytes_per_channel *
+			line6pcm->properties->capture_hw.channels_max);
+
+		if (!test_bit(LINE6_STREAM_IMPULSE, &line6pcm->in.running) &&
+		    test_bit(LINE6_STREAM_PCM, &line6pcm->in.running) &&
+		    fsize > 0)
+			line6_capture_copy(line6pcm, fbuf, fsize);
+	}
+
+	clear_bit(index, &line6pcm->in.active_urbs);
+
+	if (test_and_clear_bit(index, &line6pcm->in.unlink_urbs))
+		shutdown = 1;
+
+	if (!shutdown) {
+		submit_audio_in_urb(line6pcm);
+
+		if (!test_bit(LINE6_STREAM_IMPULSE, &line6pcm->in.running) &&
+		    test_bit(LINE6_STREAM_PCM, &line6pcm->in.running))
+			line6_capture_check_period(line6pcm, length);
+	}
+}
+
+/* open capture callback */
+static int snd_line6_capture_open(struct snd_pcm_substream *substream)
+{
+	int err;
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
+
+	err = snd_pcm_hw_constraint_ratdens(runtime, 0,
+					    SNDRV_PCM_HW_PARAM_RATE,
+					    &line6pcm->properties->rates);
+	if (err < 0)
+		return err;
+
+	line6_pcm_acquire(line6pcm, LINE6_STREAM_CAPTURE_HELPER, false);
+
+	runtime->hw = line6pcm->properties->capture_hw;
+	return 0;
+}
+
+/* close capture callback */
+static int snd_line6_capture_close(struct snd_pcm_substream *substream)
+{
+	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
+
+	line6_pcm_release(line6pcm, LINE6_STREAM_CAPTURE_HELPER);
+	return 0;
+}
+
+/* capture operators */
+const struct snd_pcm_ops snd_line6_capture_ops = {
+	.open = snd_line6_capture_open,
+	.close = snd_line6_capture_close,
+	.hw_params = snd_line6_hw_params,
+	.hw_free = snd_line6_hw_free,
+	.prepare = snd_line6_prepare,
+	.trigger = snd_line6_trigger,
+	.pointer = snd_line6_pointer,
+};
+
+int line6_create_audio_in_urbs(struct snd_line6_pcm *line6pcm)
+{
+	struct usb_line6 *line6 = line6pcm->line6;
+	int i;
+
+	line6pcm->in.urbs = kzalloc_objs(struct urb *, line6->iso_buffers);
+	if (line6pcm->in.urbs == NULL)
+		return -ENOMEM;
+
+	/* create audio URBs and fill in constant values: */
+	for (i = 0; i < line6->iso_buffers; ++i) {
+		struct urb *urb;
+
+		/* URB for audio in: */
+		urb = line6pcm->in.urbs[i] =
+		    usb_alloc_urb(LINE6_ISO_PACKETS, GFP_KERNEL);
+
+		if (urb == NULL)
+			return -ENOMEM;
+
+		urb->dev = line6->usbdev;
+		urb->pipe =
+		    usb_rcvisocpipe(line6->usbdev,
+				    line6->properties->ep_audio_r &
+				    USB_ENDPOINT_NUMBER_MASK);
+		urb->transfer_flags = URB_ISO_ASAP;
+		urb->start_frame = -1;
+		urb->number_of_packets = LINE6_ISO_PACKETS;
+		urb->interval = LINE6_ISO_INTERVAL;
+		urb->error_count = 0;
+		urb->complete = audio_in_callback;
+		if (usb_urb_ep_type_check(urb))
+			return -EINVAL;
+	}
+
+	return 0;
+}
diff --git a/sound/usb/line6/capture.h b/sound/usb/line6/capture.h
new file mode 100644
index 000000000..90572dae1
--- /dev/null
+++ b/sound/usb/line6/capture.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#ifndef CAPTURE_H
+#define CAPTURE_H
+
+#include <sound/pcm.h>
+
+#include "driver.h"
+#include "pcm.h"
+
+extern const struct snd_pcm_ops snd_line6_capture_ops;
+
+extern void line6_capture_copy(struct snd_line6_pcm *line6pcm, char *fbuf,
+			       int fsize);
+extern void line6_capture_check_period(struct snd_line6_pcm *line6pcm,
+				       int length);
+extern int line6_create_audio_in_urbs(struct snd_line6_pcm *line6pcm);
+extern int line6_submit_audio_in_all_urbs(struct snd_line6_pcm *line6pcm);
+
+#endif
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
new file mode 100644
index 000000000..191682894
--- /dev/null
+++ b/sound/usb/line6/driver.c
@@ -0,0 +1,900 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/hwdep.h>
+
+#include "capture.h"
+#include "driver.h"
+#include "midi.h"
+#include "playback.h"
+
+#define DRIVER_AUTHOR  "Markus Grabner <line6@grabner-graz.at>"
+#define DRIVER_DESC    "Line 6 USB Driver"
+
+/*
+	This is Line 6's MIDI manufacturer ID.
+*/
+const unsigned char line6_midi_id[3] = {
+	0x00, 0x01, 0x0c
+};
+EXPORT_SYMBOL_GPL(line6_midi_id);
+
+/*
+	Code to request version of POD, Variax interface
+	(and maybe other devices).
+*/
+static const char line6_request_version[] = {
+	0xf0, 0x7e, 0x7f, 0x06, 0x01, 0xf7
+};
+
+/*
+	 Class for asynchronous messages.
+*/
+struct message {
+	struct usb_line6 *line6;
+	const char *buffer;
+	int size;
+	int done;
+};
+
+/*
+	Forward declarations.
+*/
+static void line6_data_received(struct urb *urb);
+static int line6_send_raw_message_async_part(struct message *msg,
+					     struct urb *urb);
+
+/*
+	Start to listen on endpoint.
+*/
+static int line6_start_listen(struct usb_line6 *line6)
+{
+	int err;
+
+	if (line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
+		usb_fill_int_urb(line6->urb_listen, line6->usbdev,
+			usb_rcvintpipe(line6->usbdev, line6->properties->ep_ctrl_r),
+			line6->buffer_listen, LINE6_BUFSIZE_LISTEN,
+			line6_data_received, line6, line6->interval);
+	} else {
+		usb_fill_bulk_urb(line6->urb_listen, line6->usbdev,
+			usb_rcvbulkpipe(line6->usbdev, line6->properties->ep_ctrl_r),
+			line6->buffer_listen, LINE6_BUFSIZE_LISTEN,
+			line6_data_received, line6);
+	}
+
+	/* sanity checks of EP before actually submitting */
+	if (usb_urb_ep_type_check(line6->urb_listen)) {
+		dev_err(line6->ifcdev, "invalid control EP\n");
+		return -EINVAL;
+	}
+
+	line6->urb_listen->actual_length = 0;
+	err = usb_submit_urb(line6->urb_listen, GFP_ATOMIC);
+	return err;
+}
+
+/*
+	Stop listening on endpoint.
+*/
+static void line6_stop_listen(struct usb_line6 *line6)
+{
+	usb_kill_urb(line6->urb_listen);
+}
+
+/*
+	Send raw message in pieces of wMaxPacketSize bytes.
+*/
+int line6_send_raw_message(struct usb_line6 *line6, const char *buffer,
+				  int size)
+{
+	int i, done = 0;
+	const struct line6_properties *properties = line6->properties;
+
+	for (i = 0; i < size; i += line6->max_packet_size) {
+		int partial;
+		const char *frag_buf = buffer + i;
+		int frag_size = min(line6->max_packet_size, size - i);
+		int retval;
+
+		if (properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
+			retval = usb_interrupt_msg(line6->usbdev,
+						usb_sndintpipe(line6->usbdev, properties->ep_ctrl_w),
+						(char *)frag_buf, frag_size,
+						&partial, LINE6_TIMEOUT);
+		} else {
+			retval = usb_bulk_msg(line6->usbdev,
+						usb_sndbulkpipe(line6->usbdev, properties->ep_ctrl_w),
+						(char *)frag_buf, frag_size,
+						&partial, LINE6_TIMEOUT);
+		}
+
+		if (retval) {
+			dev_err(line6->ifcdev,
+				"usb_bulk_msg failed (%d)\n", retval);
+			break;
+		}
+
+		done += frag_size;
+	}
+
+	return done;
+}
+EXPORT_SYMBOL_GPL(line6_send_raw_message);
+
+/*
+	Notification of completion of asynchronous request transmission.
+*/
+static void line6_async_request_sent(struct urb *urb)
+{
+	struct message *msg = (struct message *)urb->context;
+
+	if (msg->done >= msg->size) {
+		usb_free_urb(urb);
+		kfree(msg);
+	} else
+		line6_send_raw_message_async_part(msg, urb);
+}
+
+/*
+	Asynchronously send part of a raw message.
+*/
+static int line6_send_raw_message_async_part(struct message *msg,
+					     struct urb *urb)
+{
+	int retval;
+	struct usb_line6 *line6 = msg->line6;
+	int done = msg->done;
+	int bytes = min(msg->size - done, line6->max_packet_size);
+
+	if (line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
+		usb_fill_int_urb(urb, line6->usbdev,
+			usb_sndintpipe(line6->usbdev, line6->properties->ep_ctrl_w),
+			(char *)msg->buffer + done, bytes,
+			line6_async_request_sent, msg, line6->interval);
+	} else {
+		usb_fill_bulk_urb(urb, line6->usbdev,
+			usb_sndbulkpipe(line6->usbdev, line6->properties->ep_ctrl_w),
+			(char *)msg->buffer + done, bytes,
+			line6_async_request_sent, msg);
+	}
+
+	msg->done += bytes;
+
+	/* sanity checks of EP before actually submitting */
+	retval = usb_urb_ep_type_check(urb);
+	if (retval < 0)
+		goto error;
+
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval < 0)
+		goto error;
+
+	return 0;
+
+ error:
+	dev_err(line6->ifcdev, "%s: usb_submit_urb failed (%d)\n",
+		__func__, retval);
+	usb_free_urb(urb);
+	kfree(msg);
+	return retval;
+}
+
+/*
+	Asynchronously send raw message.
+*/
+int line6_send_raw_message_async(struct usb_line6 *line6, const char *buffer,
+				 int size)
+{
+	struct message *msg;
+	struct urb *urb;
+
+	/* create message: */
+	msg = kzalloc_obj(struct message, GFP_ATOMIC);
+	if (msg == NULL)
+		return -ENOMEM;
+
+	/* create URB: */
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+
+	if (urb == NULL) {
+		kfree(msg);
+		return -ENOMEM;
+	}
+
+	/* set message data: */
+	msg->line6 = line6;
+	msg->buffer = buffer;
+	msg->size = size;
+	msg->done = 0;
+
+	/* start sending: */
+	return line6_send_raw_message_async_part(msg, urb);
+}
+EXPORT_SYMBOL_GPL(line6_send_raw_message_async);
+
+/*
+	Send asynchronous device version request.
+*/
+int line6_version_request_async(struct usb_line6 *line6)
+{
+	char *buffer;
+	int retval;
+
+	buffer = kmemdup(line6_request_version,
+			sizeof(line6_request_version), GFP_ATOMIC);
+	if (buffer == NULL)
+		return -ENOMEM;
+
+	retval = line6_send_raw_message_async(line6, buffer,
+					      sizeof(line6_request_version));
+	kfree(buffer);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(line6_version_request_async);
+
+/*
+	Send sysex message in pieces of wMaxPacketSize bytes.
+*/
+int line6_send_sysex_message(struct usb_line6 *line6, const char *buffer,
+			     int size)
+{
+	return line6_send_raw_message(line6, buffer,
+				      size + SYSEX_EXTRA_SIZE) -
+	    SYSEX_EXTRA_SIZE;
+}
+EXPORT_SYMBOL_GPL(line6_send_sysex_message);
+
+/*
+	Allocate buffer for sysex message and prepare header.
+	@param code sysex message code
+	@param size number of bytes between code and sysex end
+*/
+char *line6_alloc_sysex_buffer(struct usb_line6 *line6, int code1, int code2,
+			       int size)
+{
+	char *buffer = kmalloc(size + SYSEX_EXTRA_SIZE, GFP_ATOMIC);
+
+	if (!buffer)
+		return NULL;
+
+	buffer[0] = LINE6_SYSEX_BEGIN;
+	memcpy(buffer + 1, line6_midi_id, sizeof(line6_midi_id));
+	buffer[sizeof(line6_midi_id) + 1] = code1;
+	buffer[sizeof(line6_midi_id) + 2] = code2;
+	buffer[sizeof(line6_midi_id) + 3 + size] = LINE6_SYSEX_END;
+	return buffer;
+}
+EXPORT_SYMBOL_GPL(line6_alloc_sysex_buffer);
+
+/*
+	Notification of data received from the Line 6 device.
+*/
+static void line6_data_received(struct urb *urb)
+{
+	struct usb_line6 *line6 = (struct usb_line6 *)urb->context;
+	struct midi_buffer *mb = &line6->line6midi->midibuf_in;
+	int done;
+
+	if (urb->status == -ESHUTDOWN)
+		return;
+
+	if (line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
+		scoped_guard(spinlock_irqsave, &line6->line6midi->lock) {
+			done =
+				line6_midibuf_write(mb, urb->transfer_buffer, urb->actual_length);
+
+			if (done < urb->actual_length) {
+				line6_midibuf_ignore(mb, done);
+				dev_dbg(line6->ifcdev, "%d %d buffer overflow - message skipped\n",
+					done, urb->actual_length);
+			}
+		}
+
+		for (;;) {
+			scoped_guard(spinlock_irqsave, &line6->line6midi->lock) {
+				done =
+					line6_midibuf_read(mb, line6->buffer_message,
+							   LINE6_MIDI_MESSAGE_MAXLEN,
+							   LINE6_MIDIBUF_READ_RX);
+			}
+
+			if (done <= 0)
+				break;
+
+			line6->message_length = done;
+			line6_midi_receive(line6, line6->buffer_message, done);
+
+			if (line6->process_message)
+				line6->process_message(line6);
+		}
+	} else {
+		line6->buffer_message = urb->transfer_buffer;
+		line6->message_length = urb->actual_length;
+		if (line6->process_message)
+			line6->process_message(line6);
+		line6->buffer_message = NULL;
+	}
+
+	line6_start_listen(line6);
+}
+
+#define LINE6_READ_WRITE_STATUS_DELAY 2  /* milliseconds */
+#define LINE6_READ_WRITE_MAX_RETRIES 50
+
+/*
+	Read data from device.
+*/
+int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
+		    unsigned datalen)
+{
+	struct usb_device *usbdev = line6->usbdev;
+	int ret;
+	u8 len;
+	unsigned count;
+
+	if (address > 0xffff || datalen > 0xff)
+		return -EINVAL;
+
+	/* query the serial number: */
+	ret = usb_control_msg_send(usbdev, 0, 0x67,
+				   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+				   (datalen << 8) | 0x21, address, NULL, 0,
+				   LINE6_TIMEOUT, GFP_KERNEL);
+	if (ret) {
+		dev_err(line6->ifcdev, "read request failed (error %d)\n", ret);
+		goto exit;
+	}
+
+	/* Wait for data length. We'll get 0xff until length arrives. */
+	for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
+		mdelay(LINE6_READ_WRITE_STATUS_DELAY);
+
+		ret = usb_control_msg_recv(usbdev, 0, 0x67,
+					   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+					   0x0012, 0x0000, &len, 1,
+					   LINE6_TIMEOUT, GFP_KERNEL);
+		if (ret) {
+			dev_err(line6->ifcdev,
+				"receive length failed (error %d)\n", ret);
+			goto exit;
+		}
+
+		if (len != 0xff)
+			break;
+	}
+
+	ret = -EIO;
+	if (len == 0xff) {
+		dev_err(line6->ifcdev, "read failed after %d retries\n",
+			count);
+		goto exit;
+	} else if (len != datalen) {
+		/* should be equal or something went wrong */
+		dev_err(line6->ifcdev,
+			"length mismatch (expected %d, got %d)\n",
+			(int)datalen, len);
+		goto exit;
+	}
+
+	/* receive the result: */
+	ret = usb_control_msg_recv(usbdev, 0, 0x67,
+				   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+				   0x0013, 0x0000, data, datalen, LINE6_TIMEOUT,
+				   GFP_KERNEL);
+	if (ret)
+		dev_err(line6->ifcdev, "read failed (error %d)\n", ret);
+
+exit:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(line6_read_data);
+
+/*
+	Write data to device.
+*/
+int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
+		     unsigned datalen)
+{
+	struct usb_device *usbdev = line6->usbdev;
+	int ret;
+	unsigned char *status;
+	int count;
+
+	if (address > 0xffff || datalen > 0xffff)
+		return -EINVAL;
+
+	status = kmalloc(1, GFP_KERNEL);
+	if (!status)
+		return -ENOMEM;
+
+	ret = usb_control_msg_send(usbdev, 0, 0x67,
+				   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+				   0x0022, address, data, datalen, LINE6_TIMEOUT,
+				   GFP_KERNEL);
+	if (ret) {
+		dev_err(line6->ifcdev,
+			"write request failed (error %d)\n", ret);
+		goto exit;
+	}
+
+	for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
+		mdelay(LINE6_READ_WRITE_STATUS_DELAY);
+
+		ret = usb_control_msg_recv(usbdev, 0, 0x67,
+					   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+					   0x0012, 0x0000, status, 1, LINE6_TIMEOUT,
+					   GFP_KERNEL);
+		if (ret) {
+			dev_err(line6->ifcdev,
+				"receiving status failed (error %d)\n", ret);
+			goto exit;
+		}
+
+		if (*status != 0xff)
+			break;
+	}
+
+	if (*status == 0xff) {
+		dev_err(line6->ifcdev, "write failed after %d retries\n",
+			count);
+		ret = -EIO;
+	} else if (*status != 0) {
+		dev_err(line6->ifcdev, "write failed (error %d)\n", ret);
+		ret = -EIO;
+	}
+exit:
+	kfree(status);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(line6_write_data);
+
+/*
+	Read Line 6 device serial number.
+	(POD, TonePort, GuitarPort)
+*/
+int line6_read_serial_number(struct usb_line6 *line6, u32 *serial_number)
+{
+	return line6_read_data(line6, 0x80d0, serial_number,
+			       sizeof(*serial_number));
+}
+EXPORT_SYMBOL_GPL(line6_read_serial_number);
+
+/*
+	Card destructor.
+*/
+static void line6_destruct(struct snd_card *card)
+{
+	struct usb_line6 *line6 = card->private_data;
+	struct usb_device *usbdev = line6->usbdev;
+
+	/* Free buffer memory first. We cannot depend on the existence of private
+	 * data from the (podhd) module, it may be gone already during this call
+	 */
+	kfree(line6->buffer_message);
+
+	kfree(line6->buffer_listen);
+
+	/* then free URBs: */
+	usb_free_urb(line6->urb_listen);
+	line6->urb_listen = NULL;
+
+	/* decrement reference counters: */
+	usb_put_dev(usbdev);
+}
+
+static void line6_get_usb_properties(struct usb_line6 *line6)
+{
+	struct usb_device *usbdev = line6->usbdev;
+	const struct line6_properties *properties = line6->properties;
+	int pipe;
+	struct usb_host_endpoint *ep = NULL;
+
+	if (properties->capabilities & LINE6_CAP_CONTROL) {
+		if (properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
+			pipe = usb_rcvintpipe(line6->usbdev,
+				line6->properties->ep_ctrl_r);
+		} else {
+			pipe = usb_rcvbulkpipe(line6->usbdev,
+				line6->properties->ep_ctrl_r);
+		}
+		ep = usbdev->ep_in[usb_pipeendpoint(pipe)];
+	}
+
+	/* Control data transfer properties */
+	if (ep) {
+		line6->interval = ep->desc.bInterval;
+		line6->max_packet_size = le16_to_cpu(ep->desc.wMaxPacketSize);
+	} else {
+		if (properties->capabilities & LINE6_CAP_CONTROL) {
+			dev_err(line6->ifcdev,
+				"endpoint not available, using fallback values");
+		}
+		line6->interval = LINE6_FALLBACK_INTERVAL;
+		line6->max_packet_size = LINE6_FALLBACK_MAXPACKETSIZE;
+	}
+
+	/* Isochronous transfer properties */
+	if (usbdev->speed == USB_SPEED_LOW) {
+		line6->intervals_per_second = USB_LOW_INTERVALS_PER_SECOND;
+		line6->iso_buffers = USB_LOW_ISO_BUFFERS;
+	} else {
+		line6->intervals_per_second = USB_HIGH_INTERVALS_PER_SECOND;
+		line6->iso_buffers = USB_HIGH_ISO_BUFFERS;
+	}
+}
+
+/* Enable buffering of incoming messages, flush the buffer */
+static int line6_hwdep_open(struct snd_hwdep *hw, struct file *file)
+{
+	struct usb_line6 *line6 = hw->private_data;
+
+	/* NOTE: hwdep layer provides atomicity here */
+
+	line6->messages.active = 1;
+	line6->messages.nonblock = file->f_flags & O_NONBLOCK ? 1 : 0;
+
+	return 0;
+}
+
+/* Stop buffering */
+static int line6_hwdep_release(struct snd_hwdep *hw, struct file *file)
+{
+	struct usb_line6 *line6 = hw->private_data;
+
+	line6->messages.active = 0;
+
+	return 0;
+}
+
+/* Read from circular buffer, return to user */
+static long
+line6_hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
+					loff_t *offset)
+{
+	struct usb_line6 *line6 = hwdep->private_data;
+	long rv = 0;
+	unsigned int out_count;
+
+	if (mutex_lock_interruptible(&line6->messages.read_lock))
+		return -ERESTARTSYS;
+
+	while (kfifo_len(&line6->messages.fifo) == 0) {
+		mutex_unlock(&line6->messages.read_lock);
+
+		if (line6->messages.nonblock)
+			return -EAGAIN;
+
+		rv = wait_event_interruptible(
+			line6->messages.wait_queue,
+			kfifo_len(&line6->messages.fifo) != 0);
+		if (rv < 0)
+			return rv;
+
+		if (mutex_lock_interruptible(&line6->messages.read_lock))
+			return -ERESTARTSYS;
+	}
+
+	if (kfifo_peek_len(&line6->messages.fifo) > count) {
+		/* Buffer too small; allow re-read of the current item... */
+		rv = -EINVAL;
+	} else {
+		rv = kfifo_to_user(&line6->messages.fifo, buf, count, &out_count);
+		if (rv == 0)
+			rv = out_count;
+	}
+
+	mutex_unlock(&line6->messages.read_lock);
+	return rv;
+}
+
+/* Write directly (no buffering) to device by user*/
+static long
+line6_hwdep_write(struct snd_hwdep *hwdep, const char __user *data, long count,
+					loff_t *offset)
+{
+	struct usb_line6 *line6 = hwdep->private_data;
+	int rv;
+	char *data_copy;
+
+	if (count > line6->max_packet_size * LINE6_RAW_MESSAGES_MAXCOUNT) {
+		/* This is an arbitrary limit - still better than nothing... */
+		return -EINVAL;
+	}
+
+	data_copy = memdup_user(data, count);
+	if (IS_ERR(data_copy))
+		return PTR_ERR(data_copy);
+
+	rv = line6_send_raw_message(line6, data_copy, count);
+
+	kfree(data_copy);
+	return rv;
+}
+
+static __poll_t
+line6_hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait)
+{
+	struct usb_line6 *line6 = hwdep->private_data;
+
+	poll_wait(file, &line6->messages.wait_queue, wait);
+
+	guard(mutex)(&line6->messages.read_lock);
+	return kfifo_len(&line6->messages.fifo) == 0 ? 0 : EPOLLIN | EPOLLRDNORM;
+}
+
+static const struct snd_hwdep_ops hwdep_ops = {
+	.open    = line6_hwdep_open,
+	.release = line6_hwdep_release,
+	.read    = line6_hwdep_read,
+	.write   = line6_hwdep_write,
+	.poll    = line6_hwdep_poll,
+};
+
+/* Insert into circular buffer */
+static void line6_hwdep_push_message(struct usb_line6 *line6)
+{
+	if (!line6->messages.active)
+		return;
+
+	if (kfifo_avail(&line6->messages.fifo) >= line6->message_length) {
+		/* No race condition here, there's only one writer */
+		kfifo_in(&line6->messages.fifo,
+			line6->buffer_message, line6->message_length);
+	} /* else TODO: signal overflow */
+
+	wake_up_interruptible(&line6->messages.wait_queue);
+}
+
+static int line6_hwdep_init(struct usb_line6 *line6)
+{
+	int err;
+	struct snd_hwdep *hwdep;
+
+	/* TODO: usb_driver_claim_interface(); */
+	line6->process_message = line6_hwdep_push_message;
+	line6->messages.active = 0;
+	init_waitqueue_head(&line6->messages.wait_queue);
+	mutex_init(&line6->messages.read_lock);
+	INIT_KFIFO(line6->messages.fifo);
+
+	err = snd_hwdep_new(line6->card, "config", 0, &hwdep);
+	if (err < 0)
+		goto end;
+	strscpy(hwdep->name, "config");
+	hwdep->iface = SNDRV_HWDEP_IFACE_LINE6;
+	hwdep->ops = hwdep_ops;
+	hwdep->private_data = line6;
+	hwdep->exclusive = true;
+
+end:
+	return err;
+}
+
+static int line6_init_cap_control(struct usb_line6 *line6)
+{
+	int ret;
+
+	/* initialize USB buffers: */
+	line6->buffer_listen = kzalloc(LINE6_BUFSIZE_LISTEN, GFP_KERNEL);
+	if (!line6->buffer_listen)
+		return -ENOMEM;
+
+	line6->urb_listen = usb_alloc_urb(0, GFP_KERNEL);
+	if (!line6->urb_listen)
+		return -ENOMEM;
+
+	if (line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI) {
+		line6->buffer_message = kzalloc(LINE6_MIDI_MESSAGE_MAXLEN, GFP_KERNEL);
+		if (!line6->buffer_message)
+			return -ENOMEM;
+
+		ret = line6_init_midi(line6);
+		if (ret < 0)
+			return ret;
+	} else {
+		ret = line6_hwdep_init(line6);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = line6_start_listen(line6);
+	if (ret < 0) {
+		dev_err(line6->ifcdev, "cannot start listening: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void line6_startup_work(struct work_struct *work)
+{
+	struct usb_line6 *line6 =
+		container_of(work, struct usb_line6, startup_work.work);
+
+	if (line6->startup)
+		line6->startup(line6);
+}
+
+/*
+	Probe USB device.
+*/
+int line6_probe(struct usb_interface *interface,
+		const struct usb_device_id *id,
+		const char *driver_name,
+		const struct line6_properties *properties,
+		int (*private_init)(struct usb_line6 *, const struct usb_device_id *id),
+		size_t data_size)
+{
+	struct usb_device *usbdev = interface_to_usbdev(interface);
+	struct snd_card *card;
+	struct usb_line6 *line6;
+	int interface_number;
+	int ret;
+
+	if (WARN_ON(data_size < sizeof(*line6)))
+		return -EINVAL;
+
+	/* we don't handle multiple configurations */
+	if (usbdev->descriptor.bNumConfigurations != 1)
+		return -ENODEV;
+
+	ret = snd_card_new(&interface->dev,
+			   SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
+			   THIS_MODULE, data_size, &card);
+	if (ret < 0)
+		return ret;
+
+	/* store basic data: */
+	line6 = card->private_data;
+	line6->card = card;
+	line6->properties = properties;
+	line6->usbdev = usbdev;
+	line6->ifcdev = &interface->dev;
+	INIT_DELAYED_WORK(&line6->startup_work, line6_startup_work);
+
+	strscpy(card->id, properties->id);
+	strscpy(card->driver, driver_name);
+	strscpy(card->shortname, properties->name);
+	sprintf(card->longname, "Line 6 %s at USB %s", properties->name,
+		dev_name(line6->ifcdev));
+	card->private_free = line6_destruct;
+
+	usb_set_intfdata(interface, line6);
+
+	/* increment reference counters: */
+	usb_get_dev(usbdev);
+
+	/* initialize device info: */
+	dev_info(&interface->dev, "Line 6 %s found\n", properties->name);
+
+	/* query interface number */
+	interface_number = interface->cur_altsetting->desc.bInterfaceNumber;
+
+	/* TODO reserves the bus bandwidth even without actual transfer */
+	ret = usb_set_interface(usbdev, interface_number,
+				properties->altsetting);
+	if (ret < 0) {
+		dev_err(&interface->dev, "set_interface failed\n");
+		goto error;
+	}
+
+	line6_get_usb_properties(line6);
+
+	if (properties->capabilities & LINE6_CAP_CONTROL) {
+		ret = line6_init_cap_control(line6);
+		if (ret < 0)
+			goto error;
+	}
+
+	/* initialize device data based on device: */
+	ret = private_init(line6, id);
+	if (ret < 0)
+		goto error;
+
+	/* creation of additional special files should go here */
+
+	dev_info(&interface->dev, "Line 6 %s now attached\n",
+		 properties->name);
+
+	return 0;
+
+ error:
+	/* we can call disconnect callback here because no close-sync is
+	 * needed yet at this point
+	 */
+	line6_disconnect(interface);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(line6_probe);
+
+/*
+	Line 6 device disconnected.
+*/
+void line6_disconnect(struct usb_interface *interface)
+{
+	struct usb_line6 *line6 = usb_get_intfdata(interface);
+	struct usb_device *usbdev = interface_to_usbdev(interface);
+
+	if (!line6)
+		return;
+
+	if (WARN_ON(usbdev != line6->usbdev))
+		return;
+
+	cancel_delayed_work_sync(&line6->startup_work);
+
+	if (line6->urb_listen != NULL)
+		line6_stop_listen(line6);
+
+	snd_card_disconnect(line6->card);
+	if (line6->line6pcm)
+		line6_pcm_disconnect(line6->line6pcm);
+	if (line6->disconnect)
+		line6->disconnect(line6);
+
+	dev_info(&interface->dev, "Line 6 %s now disconnected\n",
+		 line6->properties->name);
+
+	/* make sure the device isn't destructed twice: */
+	usb_set_intfdata(interface, NULL);
+
+	snd_card_free_when_closed(line6->card);
+}
+EXPORT_SYMBOL_GPL(line6_disconnect);
+
+#ifdef CONFIG_PM
+
+/*
+	Suspend Line 6 device.
+*/
+int line6_suspend(struct usb_interface *interface, pm_message_t message)
+{
+	struct usb_line6 *line6 = usb_get_intfdata(interface);
+	struct snd_line6_pcm *line6pcm = line6->line6pcm;
+
+	snd_power_change_state(line6->card, SNDRV_CTL_POWER_D3hot);
+
+	if (line6->properties->capabilities & LINE6_CAP_CONTROL)
+		line6_stop_listen(line6);
+
+	if (line6pcm != NULL)
+		line6pcm->flags = 0;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(line6_suspend);
+
+/*
+	Resume Line 6 device.
+*/
+int line6_resume(struct usb_interface *interface)
+{
+	struct usb_line6 *line6 = usb_get_intfdata(interface);
+
+	if (line6->properties->capabilities & LINE6_CAP_CONTROL)
+		line6_start_listen(line6);
+
+	snd_power_change_state(line6->card, SNDRV_CTL_POWER_D0);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(line6_resume);
+
+#endif /* CONFIG_PM */
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
diff --git a/sound/usb/line6/driver.h b/sound/usb/line6/driver.h
new file mode 100644
index 000000000..5736ad425
--- /dev/null
+++ b/sound/usb/line6/driver.h
@@ -0,0 +1,214 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#ifndef DRIVER_H
+#define DRIVER_H
+
+#include <linux/usb.h>
+#include <linux/mutex.h>
+#include <linux/kfifo.h>
+#include <sound/core.h>
+
+#include "midi.h"
+
+/* USB 1.1 speed configuration */
+#define USB_LOW_INTERVALS_PER_SECOND 1000
+#define USB_LOW_ISO_BUFFERS 2
+
+/* USB 2.0+ speed configuration */
+#define USB_HIGH_INTERVALS_PER_SECOND 8000
+#define USB_HIGH_ISO_BUFFERS 16
+
+/* Fallback USB interval and max packet size values */
+#define LINE6_FALLBACK_INTERVAL 10
+#define LINE6_FALLBACK_MAXPACKETSIZE 16
+
+#define LINE6_TIMEOUT 1000
+#define LINE6_BUFSIZE_LISTEN 64
+#define LINE6_MIDI_MESSAGE_MAXLEN 256
+
+#define LINE6_RAW_MESSAGES_MAXCOUNT_ORDER 7
+/* 4k packets are common, BUFSIZE * MAXCOUNT should be bigger... */
+#define LINE6_RAW_MESSAGES_MAXCOUNT (1 << LINE6_RAW_MESSAGES_MAXCOUNT_ORDER)
+
+
+#if LINE6_BUFSIZE_LISTEN > 65535
+#error "Use dynamic fifo instead"
+#endif
+
+/*
+	Line 6 MIDI control commands
+*/
+#define LINE6_PARAM_CHANGE   0xb0
+#define LINE6_PROGRAM_CHANGE 0xc0
+#define LINE6_SYSEX_BEGIN    0xf0
+#define LINE6_SYSEX_END      0xf7
+#define LINE6_RESET          0xff
+
+/*
+	MIDI channel for messages initiated by the host
+	(and eventually echoed back by the device)
+*/
+#define LINE6_CHANNEL_HOST   0x00
+
+/*
+	MIDI channel for messages initiated by the device
+*/
+#define LINE6_CHANNEL_DEVICE 0x02
+
+#define LINE6_CHANNEL_UNKNOWN 5	/* don't know yet what this is good for */
+
+#define LINE6_CHANNEL_MASK 0x0f
+
+extern const unsigned char line6_midi_id[3];
+
+#define SYSEX_DATA_OFS (sizeof(line6_midi_id) + 3)
+#define SYSEX_EXTRA_SIZE (sizeof(line6_midi_id) + 4)
+
+/*
+	 Common properties of Line 6 devices.
+*/
+struct line6_properties {
+	/* Card id string (maximum 16 characters).
+	 * This can be used to address the device in ALSA programs as
+	 * "default:CARD=<id>"
+	 */
+	const char *id;
+
+	/* Card short name (maximum 32 characters) */
+	const char *name;
+
+	/* Bit vector defining this device's capabilities in line6usb driver */
+	int capabilities;
+
+	int altsetting;
+
+	unsigned int ctrl_if;
+	unsigned int ep_ctrl_r;
+	unsigned int ep_ctrl_w;
+	unsigned int ep_audio_r;
+	unsigned int ep_audio_w;
+};
+
+/* Capability bits */
+enum {
+	/* device supports settings parameter via USB */
+	LINE6_CAP_CONTROL =	1 << 0,
+	/* device supports PCM input/output via USB */
+	LINE6_CAP_PCM =		1 << 1,
+	/* device supports hardware monitoring */
+	LINE6_CAP_HWMON =	1 << 2,
+	/* device requires output data when input is read */
+	LINE6_CAP_IN_NEEDS_OUT = 1 << 3,
+	/* device uses raw MIDI via USB (data endpoints) */
+	LINE6_CAP_CONTROL_MIDI = 1 << 4,
+	/* device provides low-level information */
+	LINE6_CAP_CONTROL_INFO = 1 << 5,
+	/* device provides hardware monitoring volume control */
+	LINE6_CAP_HWMON_CTL =	1 << 6,
+};
+
+/*
+	 Common data shared by all Line 6 devices.
+	 Corresponds to a pair of USB endpoints.
+*/
+struct usb_line6 {
+	/* USB device */
+	struct usb_device *usbdev;
+
+	/* Properties */
+	const struct line6_properties *properties;
+
+	/* Interval for data USB packets */
+	int interval;
+	/* ...for isochronous transfers framing */
+	int intervals_per_second;
+
+	/* Number of isochronous URBs used for frame transfers */
+	int iso_buffers;
+
+	/* Maximum size of data USB packet */
+	int max_packet_size;
+
+	/* Device representing the USB interface */
+	struct device *ifcdev;
+
+	/* Line 6 sound card data structure.
+	 * Each device has at least MIDI or PCM.
+	 */
+	struct snd_card *card;
+
+	/* Line 6 PCM device data structure */
+	struct snd_line6_pcm *line6pcm;
+
+	/* Line 6 MIDI device data structure */
+	struct snd_line6_midi *line6midi;
+
+	/* URB for listening to POD data endpoint */
+	struct urb *urb_listen;
+
+	/* Buffer for incoming data from POD data endpoint */
+	unsigned char *buffer_listen;
+
+	/* Buffer for message to be processed, generated from MIDI layer */
+	unsigned char *buffer_message;
+
+	/* Length of message to be processed, generated from MIDI layer  */
+	int message_length;
+
+	/* Circular buffer for non-MIDI control messages */
+	struct {
+		struct mutex read_lock;
+		wait_queue_head_t wait_queue;
+		unsigned int active:1;
+		unsigned int nonblock:1;
+		STRUCT_KFIFO_REC_2(LINE6_BUFSIZE_LISTEN * LINE6_RAW_MESSAGES_MAXCOUNT)
+			fifo;
+	} messages;
+
+	/* Work for delayed PCM startup */
+	struct delayed_work startup_work;
+
+	/* If MIDI is supported, buffer_message contains the pre-processed data;
+	 * otherwise the data is only in urb_listen (buffer_incoming).
+	 */
+	void (*process_message)(struct usb_line6 *);
+	void (*disconnect)(struct usb_line6 *line6);
+	void (*startup)(struct usb_line6 *line6);
+};
+
+extern char *line6_alloc_sysex_buffer(struct usb_line6 *line6, int code1,
+				      int code2, int size);
+extern int line6_read_data(struct usb_line6 *line6, unsigned address,
+			   void *data, unsigned datalen);
+extern int line6_read_serial_number(struct usb_line6 *line6,
+				    u32 *serial_number);
+extern int line6_send_raw_message(struct usb_line6 *line6,
+					const char *buffer, int size);
+extern int line6_send_raw_message_async(struct usb_line6 *line6,
+					const char *buffer, int size);
+extern int line6_send_sysex_message(struct usb_line6 *line6,
+				    const char *buffer, int size);
+extern int line6_version_request_async(struct usb_line6 *line6);
+extern int line6_write_data(struct usb_line6 *line6, unsigned address,
+			    void *data, unsigned datalen);
+
+int line6_probe(struct usb_interface *interface,
+		const struct usb_device_id *id,
+		const char *driver_name,
+		const struct line6_properties *properties,
+		int (*private_init)(struct usb_line6 *, const struct usb_device_id *id),
+		size_t data_size);
+
+void line6_disconnect(struct usb_interface *interface);
+
+#ifdef CONFIG_PM
+int line6_suspend(struct usb_interface *interface, pm_message_t message);
+int line6_resume(struct usb_interface *interface);
+#endif
+
+#endif
diff --git a/sound/usb/line6/midi.c b/sound/usb/line6/midi.c
new file mode 100644
index 000000000..af01b6493
--- /dev/null
+++ b/sound/usb/line6/midi.c
@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/export.h>
+#include <sound/core.h>
+#include <sound/rawmidi.h>
+
+#include "driver.h"
+#include "midi.h"
+
+#define line6_rawmidi_substream_midi(substream) \
+	((struct snd_line6_midi *)((substream)->rmidi->private_data))
+
+static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
+			   int length);
+
+/*
+	Pass data received via USB to MIDI.
+*/
+void line6_midi_receive(struct usb_line6 *line6, unsigned char *data,
+			int length)
+{
+	if (line6->line6midi->substream_receive)
+		snd_rawmidi_receive(line6->line6midi->substream_receive,
+				    data, length);
+}
+
+/*
+	Read data from MIDI buffer and transmit them via USB.
+*/
+static void line6_midi_transmit(struct snd_rawmidi_substream *substream)
+{
+	struct usb_line6 *line6 =
+	    line6_rawmidi_substream_midi(substream)->line6;
+	struct snd_line6_midi *line6midi = line6->line6midi;
+	struct midi_buffer *mb = &line6midi->midibuf_out;
+	unsigned char chunk[LINE6_FALLBACK_MAXPACKETSIZE];
+	int req, done;
+
+	for (;;) {
+		req = min3(line6_midibuf_bytes_free(mb), line6->max_packet_size,
+			   LINE6_FALLBACK_MAXPACKETSIZE);
+		done = snd_rawmidi_transmit_peek(substream, chunk, req);
+
+		if (done == 0)
+			break;
+
+		line6_midibuf_write(mb, chunk, done);
+		snd_rawmidi_transmit_ack(substream, done);
+	}
+
+	for (;;) {
+		done = line6_midibuf_read(mb, chunk,
+					  LINE6_FALLBACK_MAXPACKETSIZE,
+					  LINE6_MIDIBUF_READ_TX);
+
+		if (done == 0)
+			break;
+
+		send_midi_async(line6, chunk, done);
+	}
+}
+
+/*
+	Notification of completion of MIDI transmission.
+*/
+static void midi_sent(struct urb *urb)
+{
+	int status;
+	int num;
+	struct usb_line6 *line6 = (struct usb_line6 *)urb->context;
+
+	status = urb->status;
+	kfree(urb->transfer_buffer);
+	usb_free_urb(urb);
+
+	if (status == -ESHUTDOWN)
+		return;
+
+	guard(spinlock_irqsave)(&line6->line6midi->lock);
+	num = --line6->line6midi->num_active_send_urbs;
+
+	if (num == 0) {
+		line6_midi_transmit(line6->line6midi->substream_transmit);
+		num = line6->line6midi->num_active_send_urbs;
+	}
+
+	if (num == 0)
+		wake_up(&line6->line6midi->send_wait);
+}
+
+/*
+	Send an asynchronous MIDI message.
+	Assumes that line6->line6midi->lock is held
+	(i.e., this function is serialized).
+*/
+static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
+			   int length)
+{
+	struct urb *urb;
+	int retval;
+	unsigned char *transfer_buffer;
+
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+
+	if (urb == NULL)
+		return -ENOMEM;
+
+	transfer_buffer = kmemdup(data, length, GFP_ATOMIC);
+
+	if (transfer_buffer == NULL) {
+		usb_free_urb(urb);
+		return -ENOMEM;
+	}
+
+	usb_fill_int_urb(urb, line6->usbdev,
+			 usb_sndintpipe(line6->usbdev,
+					 line6->properties->ep_ctrl_w),
+			 transfer_buffer, length, midi_sent, line6,
+			 line6->interval);
+	urb->actual_length = 0;
+	retval = usb_urb_ep_type_check(urb);
+	if (retval < 0)
+		goto error;
+
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval < 0)
+		goto error;
+
+	++line6->line6midi->num_active_send_urbs;
+	return 0;
+
+ error:
+	dev_err(line6->ifcdev, "usb_submit_urb failed\n");
+	usb_free_urb(urb);
+	return retval;
+}
+
+static int line6_midi_output_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int line6_midi_output_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static void line6_midi_output_trigger(struct snd_rawmidi_substream *substream,
+				      int up)
+{
+	struct usb_line6 *line6 =
+	    line6_rawmidi_substream_midi(substream)->line6;
+
+	line6->line6midi->substream_transmit = substream;
+	guard(spinlock_irqsave)(&line6->line6midi->lock);
+
+	if (line6->line6midi->num_active_send_urbs == 0)
+		line6_midi_transmit(substream);
+}
+
+static void line6_midi_output_drain(struct snd_rawmidi_substream *substream)
+{
+	struct usb_line6 *line6 =
+	    line6_rawmidi_substream_midi(substream)->line6;
+	struct snd_line6_midi *midi = line6->line6midi;
+
+	wait_event_interruptible(midi->send_wait,
+				 midi->num_active_send_urbs == 0);
+}
+
+static int line6_midi_input_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int line6_midi_input_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static void line6_midi_input_trigger(struct snd_rawmidi_substream *substream,
+				     int up)
+{
+	struct usb_line6 *line6 =
+	    line6_rawmidi_substream_midi(substream)->line6;
+
+	if (up)
+		line6->line6midi->substream_receive = substream;
+	else
+		line6->line6midi->substream_receive = NULL;
+}
+
+static const struct snd_rawmidi_ops line6_midi_output_ops = {
+	.open = line6_midi_output_open,
+	.close = line6_midi_output_close,
+	.trigger = line6_midi_output_trigger,
+	.drain = line6_midi_output_drain,
+};
+
+static const struct snd_rawmidi_ops line6_midi_input_ops = {
+	.open = line6_midi_input_open,
+	.close = line6_midi_input_close,
+	.trigger = line6_midi_input_trigger,
+};
+
+/* Create a MIDI device */
+static int snd_line6_new_midi(struct usb_line6 *line6,
+			      struct snd_rawmidi **rmidi_ret)
+{
+	struct snd_rawmidi *rmidi;
+	int err;
+
+	err = snd_rawmidi_new(line6->card, "Line 6 MIDI", 0, 1, 1, rmidi_ret);
+	if (err < 0)
+		return err;
+
+	rmidi = *rmidi_ret;
+	strscpy(rmidi->id, line6->properties->id);
+	strscpy(rmidi->name, line6->properties->name);
+
+	rmidi->info_flags =
+	    SNDRV_RAWMIDI_INFO_OUTPUT |
+	    SNDRV_RAWMIDI_INFO_INPUT | SNDRV_RAWMIDI_INFO_DUPLEX;
+
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+			    &line6_midi_output_ops);
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+			    &line6_midi_input_ops);
+	return 0;
+}
+
+/* MIDI device destructor */
+static void snd_line6_midi_free(struct snd_rawmidi *rmidi)
+{
+	struct snd_line6_midi *line6midi = rmidi->private_data;
+
+	line6_midibuf_destroy(&line6midi->midibuf_in);
+	line6_midibuf_destroy(&line6midi->midibuf_out);
+	kfree(line6midi);
+}
+
+/*
+	Initialize the Line 6 MIDI subsystem.
+*/
+int line6_init_midi(struct usb_line6 *line6)
+{
+	int err;
+	struct snd_rawmidi *rmidi;
+	struct snd_line6_midi *line6midi;
+
+	if (!(line6->properties->capabilities & LINE6_CAP_CONTROL_MIDI)) {
+		/* skip MIDI initialization and report success */
+		return 0;
+	}
+
+	err = snd_line6_new_midi(line6, &rmidi);
+	if (err < 0)
+		return err;
+
+	line6midi = kzalloc_obj(struct snd_line6_midi);
+	if (!line6midi)
+		return -ENOMEM;
+
+	rmidi->private_data = line6midi;
+	rmidi->private_free = snd_line6_midi_free;
+
+	init_waitqueue_head(&line6midi->send_wait);
+	spin_lock_init(&line6midi->lock);
+	line6midi->line6 = line6;
+
+	err = line6_midibuf_init(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0);
+	if (err < 0)
+		return err;
+
+	err = line6_midibuf_init(&line6midi->midibuf_out, MIDI_BUFFER_SIZE, 1);
+	if (err < 0)
+		return err;
+
+	line6->line6midi = line6midi;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(line6_init_midi);
diff --git a/sound/usb/line6/midi.h b/sound/usb/line6/midi.h
new file mode 100644
index 000000000..3409c742c
--- /dev/null
+++ b/sound/usb/line6/midi.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#ifndef MIDI_H
+#define MIDI_H
+
+#include <sound/rawmidi.h>
+
+#include "midibuf.h"
+
+#define MIDI_BUFFER_SIZE 1024
+
+struct snd_line6_midi {
+	/* Pointer back to the Line 6 driver data structure */
+	struct usb_line6 *line6;
+
+	/* MIDI substream for receiving (or NULL if not active) */
+	struct snd_rawmidi_substream *substream_receive;
+
+	/* MIDI substream for transmitting (or NULL if not active) */
+	struct snd_rawmidi_substream *substream_transmit;
+
+	/* Number of currently active MIDI send URBs */
+	int num_active_send_urbs;
+
+	/* Spin lock to protect MIDI buffer handling */
+	spinlock_t lock;
+
+	/* Wait queue for MIDI transmission */
+	wait_queue_head_t send_wait;
+
+	/* Buffer for incoming MIDI stream */
+	struct midi_buffer midibuf_in;
+
+	/* Buffer for outgoing MIDI stream */
+	struct midi_buffer midibuf_out;
+};
+
+extern int line6_init_midi(struct usb_line6 *line6);
+extern void line6_midi_receive(struct usb_line6 *line6, unsigned char *data,
+			       int length);
+
+#endif
diff --git a/sound/usb/line6/midibuf.c b/sound/usb/line6/midibuf.c
new file mode 100644
index 000000000..57fca134b
--- /dev/null
+++ b/sound/usb/line6/midibuf.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#include <linux/slab.h>
+
+#include "midibuf.h"
+
+
+static int midibuf_message_length(unsigned char code)
+{
+	int message_length;
+
+	if (code < 0x80)
+		message_length = -1;
+	else if (code < 0xf0) {
+		static const int length[] = { 3, 3, 3, 3, 2, 2, 3 };
+
+		message_length = length[(code >> 4) - 8];
+	} else {
+		static const int length[] = { -1, 2, 2, 2, -1, -1, 1, 1, 1, -1,
+			1, 1, 1, -1, 1, 1
+		};
+		message_length = length[code & 0x0f];
+	}
+
+	return message_length;
+}
+
+static int midibuf_is_empty(struct midi_buffer *this)
+{
+	return (this->pos_read == this->pos_write) && !this->full;
+}
+
+static int midibuf_is_full(struct midi_buffer *this)
+{
+	return this->full;
+}
+
+void line6_midibuf_reset(struct midi_buffer *this)
+{
+	this->pos_read = this->pos_write = this->full = 0;
+	this->command_prev = -1;
+}
+
+int line6_midibuf_init(struct midi_buffer *this, int size, int split)
+{
+	this->buf = kmalloc(size, GFP_KERNEL);
+
+	if (this->buf == NULL)
+		return -ENOMEM;
+
+	this->size = size;
+	this->split = split;
+	line6_midibuf_reset(this);
+	return 0;
+}
+
+int line6_midibuf_bytes_free(struct midi_buffer *this)
+{
+	return
+	    midibuf_is_full(this) ?
+	    0 :
+	    (this->pos_read - this->pos_write + this->size - 1) % this->size +
+	    1;
+}
+
+int line6_midibuf_bytes_used(struct midi_buffer *this)
+{
+	return
+	    midibuf_is_empty(this) ?
+	    0 :
+	    (this->pos_write - this->pos_read + this->size - 1) % this->size +
+	    1;
+}
+
+int line6_midibuf_write(struct midi_buffer *this, unsigned char *data,
+			int length)
+{
+	int bytes_free;
+	int length1, length2;
+	int skip_active_sense = 0;
+
+	if (midibuf_is_full(this) || (length <= 0))
+		return 0;
+
+	/* skip trailing active sense */
+	if (data[length - 1] == 0xfe) {
+		--length;
+		skip_active_sense = 1;
+	}
+
+	bytes_free = line6_midibuf_bytes_free(this);
+
+	if (length > bytes_free)
+		length = bytes_free;
+
+	if (length > 0) {
+		length1 = this->size - this->pos_write;
+
+		if (length < length1) {
+			/* no buffer wraparound */
+			memcpy(this->buf + this->pos_write, data, length);
+			this->pos_write += length;
+		} else {
+			/* buffer wraparound */
+			length2 = length - length1;
+			memcpy(this->buf + this->pos_write, data, length1);
+			memcpy(this->buf, data + length1, length2);
+			this->pos_write = length2;
+		}
+
+		if (this->pos_write == this->pos_read)
+			this->full = 1;
+	}
+
+	return length + skip_active_sense;
+}
+
+int line6_midibuf_read(struct midi_buffer *this, unsigned char *data,
+		       int length, int read_type)
+{
+	int bytes_used;
+	int length1, length2;
+	int command;
+	int midi_length;
+	int repeat = 0;
+	int i;
+
+	/* we need to be able to store at least a 3 byte MIDI message */
+	if (length < 3)
+		return -EINVAL;
+
+	if (midibuf_is_empty(this))
+		return 0;
+
+	bytes_used = line6_midibuf_bytes_used(this);
+
+	if (length > bytes_used)
+		length = bytes_used;
+
+	length1 = this->size - this->pos_read;
+
+	command = this->buf[this->pos_read];
+	/*
+	   PODxt always has status byte lower nibble set to 0010,
+	   when it means to send 0000, so we correct if here so
+	   that control/program changes come on channel 1 and
+	   sysex message status byte is correct
+	 */
+	if (read_type == LINE6_MIDIBUF_READ_RX) {
+		if (command == 0xb2 || command == 0xc2 || command == 0xf2) {
+			unsigned char fixed = command & 0xf0;
+			this->buf[this->pos_read] = fixed;
+			command = fixed;
+		}
+	}
+
+	/* check MIDI command length */
+	if (command & 0x80) {
+		midi_length = midibuf_message_length(command);
+		this->command_prev = command;
+	} else {
+		if (this->command_prev > 0) {
+			int midi_length_prev =
+			    midibuf_message_length(this->command_prev);
+
+			if (midi_length_prev > 1) {
+				midi_length = midi_length_prev - 1;
+				repeat = 1;
+			} else
+				midi_length = -1;
+		} else
+			midi_length = -1;
+	}
+
+	if (midi_length < 0) {
+		/* search for end of message */
+		if (length < length1) {
+			/* no buffer wraparound */
+			for (i = 1; i < length; ++i)
+				if (this->buf[this->pos_read + i] & 0x80)
+					break;
+
+			midi_length = i;
+		} else {
+			/* buffer wraparound */
+			length2 = length - length1;
+
+			for (i = 1; i < length1; ++i)
+				if (this->buf[this->pos_read + i] & 0x80)
+					break;
+
+			if (i < length1)
+				midi_length = i;
+			else {
+				for (i = 0; i < length2; ++i)
+					if (this->buf[i] & 0x80)
+						break;
+
+				midi_length = length1 + i;
+			}
+		}
+
+		if (midi_length == length)
+			midi_length = -1;	/* end of message not found */
+	}
+
+	if (midi_length < 0) {
+		if (!this->split)
+			return 0;	/* command is not yet complete */
+	} else {
+		if (length < midi_length)
+			return 0;	/* command is not yet complete */
+
+		length = midi_length;
+	}
+
+	if (length < length1) {
+		/* no buffer wraparound */
+		memcpy(data + repeat, this->buf + this->pos_read, length);
+		this->pos_read += length;
+	} else {
+		/* buffer wraparound */
+		length2 = length - length1;
+		memcpy(data + repeat, this->buf + this->pos_read, length1);
+		memcpy(data + repeat + length1, this->buf, length2);
+		this->pos_read = length2;
+	}
+
+	if (repeat)
+		data[0] = this->command_prev;
+
+	this->full = 0;
+	return length + repeat;
+}
+
+int line6_midibuf_ignore(struct midi_buffer *this, int length)
+{
+	int bytes_used = line6_midibuf_bytes_used(this);
+
+	if (length > bytes_used)
+		length = bytes_used;
+
+	this->pos_read = (this->pos_read + length) % this->size;
+	this->full = 0;
+	return length;
+}
+
+void line6_midibuf_destroy(struct midi_buffer *this)
+{
+	kfree(this->buf);
+	this->buf = NULL;
+}
diff --git a/sound/usb/line6/midibuf.h b/sound/usb/line6/midibuf.h
new file mode 100644
index 000000000..1dae5fac9
--- /dev/null
+++ b/sound/usb/line6/midibuf.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#ifndef MIDIBUF_H
+#define MIDIBUF_H
+
+#define LINE6_MIDIBUF_READ_TX 0
+#define LINE6_MIDIBUF_READ_RX 1
+
+struct midi_buffer {
+	unsigned char *buf;
+	int size;
+	int split;
+	int pos_read, pos_write;
+	int full;
+	int command_prev;
+};
+
+extern int line6_midibuf_bytes_used(struct midi_buffer *mb);
+extern int line6_midibuf_bytes_free(struct midi_buffer *mb);
+extern void line6_midibuf_destroy(struct midi_buffer *mb);
+extern int line6_midibuf_ignore(struct midi_buffer *mb, int length);
+extern int line6_midibuf_init(struct midi_buffer *mb, int size, int split);
+extern int line6_midibuf_read(struct midi_buffer *mb, unsigned char *data,
+			      int length, int read_type);
+extern void line6_midibuf_reset(struct midi_buffer *mb);
+extern int line6_midibuf_write(struct midi_buffer *mb, unsigned char *data,
+			       int length);
+
+#endif
diff --git a/sound/usb/line6/pcm.c b/sound/usb/line6/pcm.c
new file mode 100644
index 000000000..2932eaf15
--- /dev/null
+++ b/sound/usb/line6/pcm.c
@@ -0,0 +1,604 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include "capture.h"
+#include "driver.h"
+#include "playback.h"
+
+/* impulse response volume controls */
+static int snd_line6_impulse_volume_info(struct snd_kcontrol *kcontrol,
+					 struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 255;
+	return 0;
+}
+
+static int snd_line6_impulse_volume_get(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+
+	ucontrol->value.integer.value[0] = line6pcm->impulse_volume;
+	return 0;
+}
+
+static int snd_line6_impulse_volume_put(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	int value = ucontrol->value.integer.value[0];
+	int err;
+
+	if (line6pcm->impulse_volume == value)
+		return 0;
+
+	line6pcm->impulse_volume = value;
+	if (value > 0) {
+		err = line6_pcm_acquire(line6pcm, LINE6_STREAM_IMPULSE, true);
+		if (err < 0) {
+			line6pcm->impulse_volume = 0;
+			return err;
+		}
+	} else {
+		line6_pcm_release(line6pcm, LINE6_STREAM_IMPULSE);
+	}
+	return 1;
+}
+
+/* impulse response period controls */
+static int snd_line6_impulse_period_info(struct snd_kcontrol *kcontrol,
+					 struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 2000;
+	return 0;
+}
+
+static int snd_line6_impulse_period_get(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+
+	ucontrol->value.integer.value[0] = line6pcm->impulse_period;
+	return 0;
+}
+
+static int snd_line6_impulse_period_put(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	int value = ucontrol->value.integer.value[0];
+
+	if (line6pcm->impulse_period == value)
+		return 0;
+
+	line6pcm->impulse_period = value;
+	return 1;
+}
+
+/*
+	Unlink all currently active URBs.
+*/
+static void line6_unlink_audio_urbs(struct snd_line6_pcm *line6pcm,
+				    struct line6_pcm_stream *pcms)
+{
+	int i;
+
+	for (i = 0; i < line6pcm->line6->iso_buffers; i++) {
+		if (test_bit(i, &pcms->active_urbs)) {
+			if (!test_and_set_bit(i, &pcms->unlink_urbs))
+				usb_unlink_urb(pcms->urbs[i]);
+		}
+	}
+}
+
+/*
+	Wait until unlinking of all currently active URBs has been finished.
+*/
+static void line6_wait_clear_audio_urbs(struct snd_line6_pcm *line6pcm,
+					struct line6_pcm_stream *pcms)
+{
+	int timeout = HZ;
+	int i;
+	int alive;
+
+	do {
+		alive = 0;
+		for (i = 0; i < line6pcm->line6->iso_buffers; i++) {
+			if (test_bit(i, &pcms->active_urbs))
+				alive++;
+		}
+		if (!alive)
+			break;
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(1);
+	} while (--timeout > 0);
+	if (alive)
+		dev_err(line6pcm->line6->ifcdev,
+			"timeout: still %d active urbs..\n", alive);
+}
+
+static inline struct line6_pcm_stream *
+get_stream(struct snd_line6_pcm *line6pcm, int direction)
+{
+	return (direction == SNDRV_PCM_STREAM_PLAYBACK) ?
+		&line6pcm->out : &line6pcm->in;
+}
+
+/* allocate a buffer if not opened yet;
+ * call this in line6pcm.state_mutex
+ */
+static int line6_buffer_acquire(struct snd_line6_pcm *line6pcm,
+				struct line6_pcm_stream *pstr, int direction, int type)
+{
+	const int pkt_size =
+		(direction == SNDRV_PCM_STREAM_PLAYBACK) ?
+			line6pcm->max_packet_size_out :
+			line6pcm->max_packet_size_in;
+
+	/* Invoked multiple times in a row so allocate once only */
+	if (!test_and_set_bit(type, &pstr->opened) && !pstr->buffer) {
+		pstr->buffer =
+			kmalloc(array3_size(line6pcm->line6->iso_buffers,
+					    LINE6_ISO_PACKETS, pkt_size),
+				GFP_KERNEL);
+		if (!pstr->buffer)
+			return -ENOMEM;
+	}
+	return 0;
+}
+
+/* free a buffer if all streams are closed;
+ * call this in line6pcm.state_mutex
+ */
+static void line6_buffer_release(struct snd_line6_pcm *line6pcm,
+				 struct line6_pcm_stream *pstr, int type)
+{
+	clear_bit(type, &pstr->opened);
+	if (!pstr->opened) {
+		line6_wait_clear_audio_urbs(line6pcm, pstr);
+		kfree(pstr->buffer);
+		pstr->buffer = NULL;
+	}
+}
+
+/* start a PCM stream */
+static int line6_stream_start(struct snd_line6_pcm *line6pcm, int direction,
+			      int type)
+{
+	struct line6_pcm_stream *pstr = get_stream(line6pcm, direction);
+	int ret = 0;
+
+	guard(spinlock_irqsave)(&pstr->lock);
+	if (!test_and_set_bit(type, &pstr->running) &&
+	    !(pstr->active_urbs || pstr->unlink_urbs)) {
+		pstr->count = 0;
+		/* Submit all currently available URBs */
+		if (direction == SNDRV_PCM_STREAM_PLAYBACK)
+			ret = line6_submit_audio_out_all_urbs(line6pcm);
+		else
+			ret = line6_submit_audio_in_all_urbs(line6pcm);
+	}
+
+	if (ret < 0)
+		clear_bit(type, &pstr->running);
+	return ret;
+}
+
+/* stop a PCM stream; this doesn't sync with the unlinked URBs */
+static void line6_stream_stop(struct snd_line6_pcm *line6pcm, int direction,
+			  int type)
+{
+	struct line6_pcm_stream *pstr = get_stream(line6pcm, direction);
+
+	scoped_guard(spinlock_irqsave, &pstr->lock) {
+		clear_bit(type, &pstr->running);
+		if (pstr->running)
+			return;
+	}
+
+	line6_unlink_audio_urbs(line6pcm, pstr);
+	if (direction == SNDRV_PCM_STREAM_CAPTURE) {
+		guard(spinlock_irqsave)(&pstr->lock);
+		line6pcm->prev_fbuf = NULL;
+		line6pcm->prev_fsize = 0;
+	}
+}
+
+/* common PCM trigger callback */
+int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
+	struct snd_pcm_substream *s;
+	int err;
+
+	clear_bit(LINE6_FLAG_PREPARED, &line6pcm->flags);
+
+	snd_pcm_group_for_each_entry(s, substream) {
+		if (s->pcm->card != substream->pcm->card)
+			continue;
+
+		switch (cmd) {
+		case SNDRV_PCM_TRIGGER_START:
+		case SNDRV_PCM_TRIGGER_RESUME:
+			if (s->stream == SNDRV_PCM_STREAM_CAPTURE &&
+				(line6pcm->line6->properties->capabilities &
+					LINE6_CAP_IN_NEEDS_OUT)) {
+				err = line6_stream_start(line6pcm, SNDRV_PCM_STREAM_PLAYBACK,
+						 LINE6_STREAM_CAPTURE_HELPER);
+				if (err < 0)
+					return err;
+			}
+			err = line6_stream_start(line6pcm, s->stream,
+						 LINE6_STREAM_PCM);
+			if (err < 0)
+				return err;
+			break;
+
+		case SNDRV_PCM_TRIGGER_STOP:
+		case SNDRV_PCM_TRIGGER_SUSPEND:
+			if (s->stream == SNDRV_PCM_STREAM_CAPTURE &&
+				(line6pcm->line6->properties->capabilities &
+					LINE6_CAP_IN_NEEDS_OUT)) {
+				line6_stream_stop(line6pcm, SNDRV_PCM_STREAM_PLAYBACK,
+					  LINE6_STREAM_CAPTURE_HELPER);
+			}
+			line6_stream_stop(line6pcm, s->stream,
+					  LINE6_STREAM_PCM);
+			break;
+
+		case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+			if (s->stream != SNDRV_PCM_STREAM_PLAYBACK)
+				return -EINVAL;
+			set_bit(LINE6_FLAG_PAUSE_PLAYBACK, &line6pcm->flags);
+			break;
+
+		case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+			if (s->stream != SNDRV_PCM_STREAM_PLAYBACK)
+				return -EINVAL;
+			clear_bit(LINE6_FLAG_PAUSE_PLAYBACK, &line6pcm->flags);
+			break;
+
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+/* common PCM pointer callback */
+snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream *substream)
+{
+	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
+	struct line6_pcm_stream *pstr = get_stream(line6pcm, substream->stream);
+
+	return pstr->pos_done;
+}
+
+/* Stop and release duplex streams */
+static void __line6_pcm_release(struct snd_line6_pcm *line6pcm, int type)
+{
+	struct line6_pcm_stream *pstr;
+	int dir;
+
+	for (dir = 0; dir < 2; dir++)
+		line6_stream_stop(line6pcm, dir, type);
+	for (dir = 0; dir < 2; dir++) {
+		pstr = get_stream(line6pcm, dir);
+		line6_buffer_release(line6pcm, pstr, type);
+	}
+}
+
+/* Stop and release duplex streams */
+void line6_pcm_release(struct snd_line6_pcm *line6pcm, int type)
+{
+	guard(mutex)(&line6pcm->state_mutex);
+	__line6_pcm_release(line6pcm, type);
+}
+EXPORT_SYMBOL_GPL(line6_pcm_release);
+
+/* Acquire and optionally start duplex streams:
+ * type is either LINE6_STREAM_IMPULSE or LINE6_STREAM_MONITOR
+ */
+int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int type, bool start)
+{
+	struct line6_pcm_stream *pstr;
+	int ret = 0, dir;
+
+	/* TODO: We should assert SNDRV_PCM_STREAM_PLAYBACK/CAPTURE == 0/1 */
+	guard(mutex)(&line6pcm->state_mutex);
+	for (dir = 0; dir < 2; dir++) {
+		pstr = get_stream(line6pcm, dir);
+		ret = line6_buffer_acquire(line6pcm, pstr, dir, type);
+		if (ret < 0)
+			goto error;
+		if (!pstr->running)
+			line6_wait_clear_audio_urbs(line6pcm, pstr);
+	}
+	if (start) {
+		for (dir = 0; dir < 2; dir++) {
+			ret = line6_stream_start(line6pcm, dir, type);
+			if (ret < 0)
+				goto error;
+		}
+	}
+ error:
+	if (ret < 0)
+		__line6_pcm_release(line6pcm, type);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(line6_pcm_acquire);
+
+/* common PCM hw_params callback */
+int snd_line6_hw_params(struct snd_pcm_substream *substream,
+			struct snd_pcm_hw_params *hw_params)
+{
+	int ret;
+	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
+	struct line6_pcm_stream *pstr = get_stream(line6pcm, substream->stream);
+
+	guard(mutex)(&line6pcm->state_mutex);
+	ret = line6_buffer_acquire(line6pcm, pstr, substream->stream,
+	                           LINE6_STREAM_PCM);
+	if (ret < 0)
+		return ret;
+
+	pstr->period = params_period_bytes(hw_params);
+	return 0;
+}
+
+/* common PCM hw_free callback */
+int snd_line6_hw_free(struct snd_pcm_substream *substream)
+{
+	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
+	struct line6_pcm_stream *pstr = get_stream(line6pcm, substream->stream);
+
+	guard(mutex)(&line6pcm->state_mutex);
+	line6_buffer_release(line6pcm, pstr, LINE6_STREAM_PCM);
+	return 0;
+}
+
+
+/* control info callback */
+static int snd_line6_control_playback_info(struct snd_kcontrol *kcontrol,
+					   struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 2;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 256;
+	return 0;
+}
+
+/* control get callback */
+static int snd_line6_control_playback_get(struct snd_kcontrol *kcontrol,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	int i;
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+
+	for (i = 0; i < 2; i++)
+		ucontrol->value.integer.value[i] = line6pcm->volume_playback[i];
+
+	return 0;
+}
+
+/* control put callback */
+static int snd_line6_control_playback_put(struct snd_kcontrol *kcontrol,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	int i, changed = 0;
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+
+	for (i = 0; i < 2; i++)
+		if (line6pcm->volume_playback[i] !=
+		    ucontrol->value.integer.value[i]) {
+			line6pcm->volume_playback[i] =
+			    ucontrol->value.integer.value[i];
+			changed = 1;
+		}
+
+	return changed;
+}
+
+/* control definition */
+static const struct snd_kcontrol_new line6_controls[] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "PCM Playback Volume",
+		.info = snd_line6_control_playback_info,
+		.get = snd_line6_control_playback_get,
+		.put = snd_line6_control_playback_put
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Impulse Response Volume",
+		.info = snd_line6_impulse_volume_info,
+		.get = snd_line6_impulse_volume_get,
+		.put = snd_line6_impulse_volume_put
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Impulse Response Period",
+		.info = snd_line6_impulse_period_info,
+		.get = snd_line6_impulse_period_get,
+		.put = snd_line6_impulse_period_put
+	},
+};
+
+/*
+	Cleanup the PCM device.
+*/
+static void cleanup_urbs(struct line6_pcm_stream *pcms, int iso_buffers)
+{
+	int i;
+
+	/* Most likely impossible in current code... */
+	if (pcms->urbs == NULL)
+		return;
+
+	for (i = 0; i < iso_buffers; i++) {
+		if (pcms->urbs[i]) {
+			usb_kill_urb(pcms->urbs[i]);
+			usb_free_urb(pcms->urbs[i]);
+		}
+	}
+	kfree(pcms->urbs);
+	pcms->urbs = NULL;
+}
+
+static void line6_cleanup_pcm(struct snd_pcm *pcm)
+{
+	struct snd_line6_pcm *line6pcm = snd_pcm_chip(pcm);
+
+	cleanup_urbs(&line6pcm->out, line6pcm->line6->iso_buffers);
+	cleanup_urbs(&line6pcm->in, line6pcm->line6->iso_buffers);
+	kfree(line6pcm);
+}
+
+/* create a PCM device */
+static int snd_line6_new_pcm(struct usb_line6 *line6, struct snd_pcm **pcm_ret)
+{
+	struct snd_pcm *pcm;
+	int err;
+
+	err = snd_pcm_new(line6->card, (char *)line6->properties->name,
+			  0, 1, 1, pcm_ret);
+	if (err < 0)
+		return err;
+	pcm = *pcm_ret;
+	strscpy(pcm->name, line6->properties->name);
+
+	/* set operators */
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
+			&snd_line6_playback_ops);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_line6_capture_ops);
+
+	/* pre-allocation of buffers */
+	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
+				       NULL, 64 * 1024, 128 * 1024);
+	return 0;
+}
+
+/*
+	Sync with PCM stream stops.
+*/
+void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm)
+{
+	line6_unlink_audio_urbs(line6pcm, &line6pcm->out);
+	line6_unlink_audio_urbs(line6pcm, &line6pcm->in);
+	line6_wait_clear_audio_urbs(line6pcm, &line6pcm->out);
+	line6_wait_clear_audio_urbs(line6pcm, &line6pcm->in);
+}
+
+/*
+	Create and register the PCM device and mixer entries.
+	Create URBs for playback and capture.
+*/
+int line6_init_pcm(struct usb_line6 *line6,
+		   struct line6_pcm_properties *properties)
+{
+	int i, err;
+	unsigned ep_read = line6->properties->ep_audio_r;
+	unsigned ep_write = line6->properties->ep_audio_w;
+	struct snd_pcm *pcm;
+	struct snd_line6_pcm *line6pcm;
+
+	if (!(line6->properties->capabilities & LINE6_CAP_PCM))
+		return 0;	/* skip PCM initialization and report success */
+
+	err = snd_line6_new_pcm(line6, &pcm);
+	if (err < 0)
+		return err;
+
+	line6pcm = kzalloc_obj(*line6pcm);
+	if (!line6pcm)
+		return -ENOMEM;
+
+	mutex_init(&line6pcm->state_mutex);
+	line6pcm->pcm = pcm;
+	line6pcm->properties = properties;
+	line6pcm->volume_playback[0] = line6pcm->volume_playback[1] = 255;
+	line6pcm->volume_monitor = 255;
+	line6pcm->line6 = line6;
+
+	spin_lock_init(&line6pcm->out.lock);
+	spin_lock_init(&line6pcm->in.lock);
+	line6pcm->impulse_period = LINE6_IMPULSE_DEFAULT_PERIOD;
+
+	line6->line6pcm = line6pcm;
+
+	pcm->private_data = line6pcm;
+	pcm->private_free = line6_cleanup_pcm;
+
+	line6pcm->max_packet_size_in =
+		usb_maxpacket(line6->usbdev,
+			usb_rcvisocpipe(line6->usbdev, ep_read));
+	line6pcm->max_packet_size_out =
+		usb_maxpacket(line6->usbdev,
+			usb_sndisocpipe(line6->usbdev, ep_write));
+	if (!line6pcm->max_packet_size_in || !line6pcm->max_packet_size_out) {
+		dev_err(line6pcm->line6->ifcdev,
+			"cannot get proper max packet size\n");
+		return -EINVAL;
+	}
+
+	err = line6_create_audio_out_urbs(line6pcm);
+	if (err < 0)
+		return err;
+
+	err = line6_create_audio_in_urbs(line6pcm);
+	if (err < 0)
+		return err;
+
+	/* mixer: */
+	for (i = 0; i < ARRAY_SIZE(line6_controls); i++) {
+		err = snd_ctl_add(line6->card,
+				  snd_ctl_new1(&line6_controls[i], line6pcm));
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(line6_init_pcm);
+
+/* prepare pcm callback */
+int snd_line6_prepare(struct snd_pcm_substream *substream)
+{
+	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
+	struct line6_pcm_stream *pstr = get_stream(line6pcm, substream->stream);
+
+	guard(mutex)(&line6pcm->state_mutex);
+	if (!pstr->running)
+		line6_wait_clear_audio_urbs(line6pcm, pstr);
+
+	if (!test_and_set_bit(LINE6_FLAG_PREPARED, &line6pcm->flags)) {
+		line6pcm->out.count = 0;
+		line6pcm->out.pos = 0;
+		line6pcm->out.pos_done = 0;
+		line6pcm->out.bytes = 0;
+		line6pcm->in.count = 0;
+		line6pcm->in.pos_done = 0;
+		line6pcm->in.bytes = 0;
+	}
+
+	return 0;
+}
diff --git a/sound/usb/line6/pcm.h b/sound/usb/line6/pcm.h
new file mode 100644
index 000000000..a15913bf2
--- /dev/null
+++ b/sound/usb/line6/pcm.h
@@ -0,0 +1,195 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+/*
+	PCM interface to POD series devices.
+*/
+
+#ifndef PCM_H
+#define PCM_H
+
+#include <sound/pcm.h>
+
+#include "driver.h"
+
+/*
+	number of USB frames per URB
+	The Line 6 Windows driver always transmits two frames per packet, but
+	the Linux driver performs significantly better (i.e., lower latency)
+	with only one frame per packet.
+*/
+#define LINE6_ISO_PACKETS	1
+
+/* in a "full speed" device (such as the PODxt Pro) this means 1ms,
+ *  for "high speed" it's 1/8ms
+ */
+#define LINE6_ISO_INTERVAL	1
+
+#define LINE6_IMPULSE_DEFAULT_PERIOD 100
+
+/*
+	Get substream from Line 6 PCM data structure
+*/
+#define get_substream(line6pcm, stream)	\
+		(line6pcm->pcm->streams[stream].substream)
+
+/*
+	PCM mode bits.
+
+	There are several features of the Line 6 USB driver which require PCM
+	data to be exchanged with the device:
+	*) PCM playback and capture via ALSA
+	*) software monitoring (for devices without hardware monitoring)
+	*) optional impulse response measurement
+	However, from the device's point of view, there is just a single
+	capture and playback stream, which must be shared between these
+	subsystems. It is therefore necessary to maintain the state of the
+	subsystems with respect to PCM usage.
+
+	We define two bit flags, "opened" and "running", for each playback
+	or capture stream.  Both can contain the bit flag corresponding to
+	LINE6_STREAM_* type,
+	  LINE6_STREAM_PCM = ALSA PCM playback or capture
+	  LINE6_STREAM_MONITOR = software monitoring
+	  IMPULSE = optional impulse response measurement
+	The opened flag indicates whether the buffer is allocated while
+	the running flag indicates whether the stream is running.
+
+	For monitor or impulse operations, the driver needs to call
+	line6_pcm_acquire() or line6_pcm_release() with the appropriate
+	LINE6_STREAM_* flag.
+*/
+
+/* stream types */
+enum {
+	LINE6_STREAM_PCM,
+	LINE6_STREAM_MONITOR,
+	LINE6_STREAM_IMPULSE,
+	LINE6_STREAM_CAPTURE_HELPER,
+};
+
+/* misc bit flags for PCM operation */
+enum {
+	LINE6_FLAG_PAUSE_PLAYBACK,
+	LINE6_FLAG_PREPARED,
+};
+
+struct line6_pcm_properties {
+	struct snd_pcm_hardware playback_hw, capture_hw;
+	struct snd_pcm_hw_constraint_ratdens rates;
+	int bytes_per_channel;
+};
+
+struct line6_pcm_stream {
+	/* allocated URBs */
+	struct urb **urbs;
+
+	/* Temporary buffer;
+	 * Since the packet size is not known in advance, this buffer is
+	 * large enough to store maximum size packets.
+	 */
+	unsigned char *buffer;
+
+	/* Free frame position in the buffer. */
+	snd_pcm_uframes_t pos;
+
+	/* Count processed bytes;
+	 * This is modulo period size (to determine when a period is finished).
+	 */
+	unsigned bytes;
+
+	/* Counter to create desired sample rate */
+	unsigned count;
+
+	/* period size in bytes */
+	unsigned period;
+
+	/* Processed frame position in the buffer;
+	 * The contents of the ring buffer have been consumed by the USB
+	 * subsystem (i.e., sent to the USB device) up to this position.
+	 */
+	snd_pcm_uframes_t pos_done;
+
+	/* Bit mask of active URBs */
+	unsigned long active_urbs;
+
+	/* Bit mask of URBs currently being unlinked */
+	unsigned long unlink_urbs;
+
+	/* Spin lock to protect updates of the buffer positions (not contents)
+	 */
+	spinlock_t lock;
+
+	/* Bit flags for operational stream types */
+	unsigned long opened;
+
+	/* Bit flags for running stream types */
+	unsigned long running;
+
+	int last_frame;
+};
+
+struct snd_line6_pcm {
+	/* Pointer back to the Line 6 driver data structure */
+	struct usb_line6 *line6;
+
+	/* Properties. */
+	struct line6_pcm_properties *properties;
+
+	/* ALSA pcm stream */
+	struct snd_pcm *pcm;
+
+	/* protection to state changes of in/out streams */
+	struct mutex state_mutex;
+
+	/* Capture and playback streams */
+	struct line6_pcm_stream in;
+	struct line6_pcm_stream out;
+
+	/* Previously captured frame (for software monitoring) */
+	unsigned char *prev_fbuf;
+
+	/* Size of previously captured frame (for software monitoring/sync) */
+	int prev_fsize;
+
+	/* Maximum size of USB packet */
+	int max_packet_size_in;
+	int max_packet_size_out;
+
+	/* PCM playback volume (left and right) */
+	int volume_playback[2];
+
+	/* PCM monitor volume */
+	int volume_monitor;
+
+	/* Volume of impulse response test signal (if zero, test is disabled) */
+	int impulse_volume;
+
+	/* Period of impulse response test signal */
+	int impulse_period;
+
+	/* Counter for impulse response test signal */
+	int impulse_count;
+
+	/* Several status bits (see LINE6_FLAG_*) */
+	unsigned long flags;
+};
+
+extern int line6_init_pcm(struct usb_line6 *line6,
+			  struct line6_pcm_properties *properties);
+extern int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd);
+extern int snd_line6_prepare(struct snd_pcm_substream *substream);
+extern int snd_line6_hw_params(struct snd_pcm_substream *substream,
+			       struct snd_pcm_hw_params *hw_params);
+extern int snd_line6_hw_free(struct snd_pcm_substream *substream);
+extern snd_pcm_uframes_t snd_line6_pointer(struct snd_pcm_substream *substream);
+extern void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm);
+extern int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int type,
+			       bool start);
+extern void line6_pcm_release(struct snd_line6_pcm *line6pcm, int type);
+
+#endif
diff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c
new file mode 100644
index 000000000..aa6ddf874
--- /dev/null
+++ b/sound/usb/line6/playback.c
@@ -0,0 +1,445 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include "capture.h"
+#include "driver.h"
+#include "pcm.h"
+#include "playback.h"
+
+/*
+	Software stereo volume control.
+*/
+static void change_volume(struct urb *urb_out, int volume[],
+			  int bytes_per_frame)
+{
+	int chn = 0;
+
+	if (volume[0] == 256 && volume[1] == 256)
+		return;		/* maximum volume - no change */
+
+	if (bytes_per_frame == 4) {
+		__le16 *p, *buf_end;
+
+		p = (__le16 *)urb_out->transfer_buffer;
+		buf_end = p + urb_out->transfer_buffer_length / sizeof(*p);
+
+		for (; p < buf_end; ++p) {
+			short pv = le16_to_cpu(*p);
+			int val = (pv * volume[chn & 1]) >> 8;
+			pv = clamp(val, -0x8000, 0x7fff);
+			*p = cpu_to_le16(pv);
+			++chn;
+		}
+	} else if (bytes_per_frame == 6) {
+		unsigned char *p, *buf_end;
+
+		p = (unsigned char *)urb_out->transfer_buffer;
+		buf_end = p + urb_out->transfer_buffer_length;
+
+		for (; p < buf_end; p += 3) {
+			int val;
+
+			val = p[0] + (p[1] << 8) + ((signed char)p[2] << 16);
+			val = (val * volume[chn & 1]) >> 8;
+			val = clamp(val, -0x800000, 0x7fffff);
+			p[0] = val;
+			p[1] = val >> 8;
+			p[2] = val >> 16;
+			++chn;
+		}
+	}
+}
+
+/*
+	Create signal for impulse response test.
+*/
+static void create_impulse_test_signal(struct snd_line6_pcm *line6pcm,
+				       struct urb *urb_out, int bytes_per_frame)
+{
+	int frames = urb_out->transfer_buffer_length / bytes_per_frame;
+
+	if (bytes_per_frame == 4) {
+		int i;
+		short *pi = (short *)line6pcm->prev_fbuf;
+		short *po = (short *)urb_out->transfer_buffer;
+
+		for (i = 0; i < frames; ++i) {
+			po[0] = pi[0];
+			po[1] = 0;
+			pi += 2;
+			po += 2;
+		}
+	} else if (bytes_per_frame == 6) {
+		int i, j;
+		unsigned char *pi = line6pcm->prev_fbuf;
+		unsigned char *po = urb_out->transfer_buffer;
+
+		for (i = 0; i < frames; ++i) {
+			for (j = 0; j < bytes_per_frame / 2; ++j)
+				po[j] = pi[j];
+
+			for (; j < bytes_per_frame; ++j)
+				po[j] = 0;
+
+			pi += bytes_per_frame;
+			po += bytes_per_frame;
+		}
+	}
+	if (--line6pcm->impulse_count <= 0) {
+		((unsigned char *)(urb_out->transfer_buffer))[bytes_per_frame -
+							      1] =
+		    line6pcm->impulse_volume;
+		line6pcm->impulse_count = line6pcm->impulse_period;
+	}
+}
+
+/*
+	Add signal to buffer for software monitoring.
+*/
+static void add_monitor_signal(struct urb *urb_out, unsigned char *signal,
+			       int volume, int bytes_per_frame)
+{
+	if (volume == 0)
+		return;		/* zero volume - no change */
+
+	if (bytes_per_frame == 4) {
+		__le16 *pi, *po, *buf_end;
+
+		pi = (__le16 *)signal;
+		po = (__le16 *)urb_out->transfer_buffer;
+		buf_end = po + urb_out->transfer_buffer_length / sizeof(*po);
+
+		for (; po < buf_end; ++pi, ++po) {
+			short pov = le16_to_cpu(*po);
+			short piv = le16_to_cpu(*pi);
+			int val = pov + ((piv * volume) >> 8);
+			pov = clamp(val, -0x8000, 0x7fff);
+			*po = cpu_to_le16(pov);
+		}
+	}
+
+	/*
+	   We don't need to handle devices with 6 bytes per frame here
+	   since they all support hardware monitoring.
+	 */
+}
+
+/*
+	Find a free URB, prepare audio data, and submit URB.
+	must be called in line6pcm->out.lock context
+*/
+static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm)
+{
+	int index;
+	int i, urb_size, urb_frames;
+	int ret;
+	const int bytes_per_frame =
+		line6pcm->properties->bytes_per_channel *
+		line6pcm->properties->playback_hw.channels_max;
+	const int frame_increment =
+		line6pcm->properties->rates.rats[0].num_min;
+	const int frame_factor =
+		line6pcm->properties->rates.rats[0].den *
+		(line6pcm->line6->intervals_per_second / LINE6_ISO_INTERVAL);
+	struct urb *urb_out;
+
+	index = find_first_zero_bit(&line6pcm->out.active_urbs,
+				    line6pcm->line6->iso_buffers);
+
+	if (index < 0 || index >= line6pcm->line6->iso_buffers) {
+		dev_err(line6pcm->line6->ifcdev, "no free URB found\n");
+		return -EINVAL;
+	}
+
+	urb_out = line6pcm->out.urbs[index];
+	urb_size = 0;
+
+	/* TODO: this may not work for LINE6_ISO_PACKETS != 1 */
+	for (i = 0; i < LINE6_ISO_PACKETS; ++i) {
+		/* compute frame size for given sampling rate */
+		int fsize = 0;
+		struct usb_iso_packet_descriptor *fout =
+		    &urb_out->iso_frame_desc[i];
+
+		fsize = line6pcm->prev_fsize;
+		if (fsize == 0) {
+			int n;
+
+			line6pcm->out.count += frame_increment;
+			n = line6pcm->out.count / frame_factor;
+			line6pcm->out.count -= n * frame_factor;
+			fsize = n;
+		}
+
+		fsize *= bytes_per_frame;
+
+		if (fsize > line6pcm->max_packet_size_out) {
+			dev_err(line6pcm->line6->ifcdev,
+				"playback packet too large: %d > %d\n",
+				fsize, line6pcm->max_packet_size_out);
+			return -EMSGSIZE;
+		}
+
+		fout->offset = urb_size;
+		fout->length = fsize;
+		urb_size += fsize;
+	}
+
+	if (urb_size == 0) {
+		/* can't determine URB size */
+		dev_err(line6pcm->line6->ifcdev, "driver bug: urb_size = 0\n");
+		return -EINVAL;
+	}
+
+	urb_frames = urb_size / bytes_per_frame;
+	urb_out->transfer_buffer =
+	    line6pcm->out.buffer +
+	    index * LINE6_ISO_PACKETS * line6pcm->max_packet_size_out;
+	urb_out->transfer_buffer_length = urb_size;
+	urb_out->context = line6pcm;
+
+	if (test_bit(LINE6_STREAM_PCM, &line6pcm->out.running) &&
+	    !test_bit(LINE6_FLAG_PAUSE_PLAYBACK, &line6pcm->flags)) {
+		struct snd_pcm_runtime *runtime =
+		    get_substream(line6pcm, SNDRV_PCM_STREAM_PLAYBACK)->runtime;
+
+		if (line6pcm->out.pos + urb_frames > runtime->buffer_size) {
+			/*
+			   The transferred area goes over buffer boundary,
+			   copy the data to the temp buffer.
+			 */
+			int len;
+
+			len = runtime->buffer_size - line6pcm->out.pos;
+
+			if (len > 0) {
+				memcpy(urb_out->transfer_buffer,
+				       runtime->dma_area +
+				       line6pcm->out.pos * bytes_per_frame,
+				       len * bytes_per_frame);
+				memcpy(urb_out->transfer_buffer +
+				       len * bytes_per_frame, runtime->dma_area,
+				       (urb_frames - len) * bytes_per_frame);
+			} else
+				dev_err(line6pcm->line6->ifcdev, "driver bug: len = %d\n",
+					len);
+		} else {
+			memcpy(urb_out->transfer_buffer,
+			       runtime->dma_area +
+			       line6pcm->out.pos * bytes_per_frame,
+			       urb_out->transfer_buffer_length);
+		}
+
+		line6pcm->out.pos += urb_frames;
+		if (line6pcm->out.pos >= runtime->buffer_size)
+			line6pcm->out.pos -= runtime->buffer_size;
+
+		change_volume(urb_out, line6pcm->volume_playback,
+			      bytes_per_frame);
+	} else {
+		memset(urb_out->transfer_buffer, 0,
+		       urb_out->transfer_buffer_length);
+	}
+
+	spin_lock_nested(&line6pcm->in.lock, SINGLE_DEPTH_NESTING);
+	if (line6pcm->prev_fbuf) {
+		if (test_bit(LINE6_STREAM_IMPULSE, &line6pcm->out.running)) {
+			create_impulse_test_signal(line6pcm, urb_out,
+						   bytes_per_frame);
+			if (test_bit(LINE6_STREAM_PCM, &line6pcm->in.running)) {
+				line6_capture_copy(line6pcm,
+						   urb_out->transfer_buffer,
+						   urb_out->
+						   transfer_buffer_length);
+				line6_capture_check_period(line6pcm,
+					urb_out->transfer_buffer_length);
+			}
+		} else {
+			if (!(line6pcm->line6->properties->capabilities & LINE6_CAP_HWMON)
+			    && line6pcm->out.running && line6pcm->in.running)
+				add_monitor_signal(urb_out, line6pcm->prev_fbuf,
+						   line6pcm->volume_monitor,
+						   bytes_per_frame);
+		}
+		line6pcm->prev_fbuf = NULL;
+		line6pcm->prev_fsize = 0;
+	}
+	spin_unlock(&line6pcm->in.lock);
+
+	ret = usb_submit_urb(urb_out, GFP_ATOMIC);
+
+	if (ret == 0)
+		set_bit(index, &line6pcm->out.active_urbs);
+	else
+		dev_err(line6pcm->line6->ifcdev,
+			"URB out #%d submission failed (%d)\n", index, ret);
+
+	return 0;
+}
+
+/*
+	Submit all currently available playback URBs.
+	must be called in line6pcm->out.lock context
+ */
+int line6_submit_audio_out_all_urbs(struct snd_line6_pcm *line6pcm)
+{
+	int ret = 0, i;
+
+	for (i = 0; i < line6pcm->line6->iso_buffers; ++i) {
+		ret = submit_audio_out_urb(line6pcm);
+		if (ret < 0)
+			break;
+	}
+
+	return ret;
+}
+
+/*
+	Callback for completed playback URB.
+*/
+static void audio_out_callback(struct urb *urb)
+{
+	int i, index, length = 0, shutdown = 0;
+	unsigned long flags;
+	struct snd_line6_pcm *line6pcm = (struct snd_line6_pcm *)urb->context;
+	struct snd_pcm_substream *substream =
+	    get_substream(line6pcm, SNDRV_PCM_STREAM_PLAYBACK);
+	const int bytes_per_frame =
+		line6pcm->properties->bytes_per_channel *
+		line6pcm->properties->playback_hw.channels_max;
+
+#if USE_CLEAR_BUFFER_WORKAROUND
+	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
+#endif
+
+	line6pcm->out.last_frame = urb->start_frame;
+
+	/* find index of URB */
+	for (index = 0; index < line6pcm->line6->iso_buffers; index++)
+		if (urb == line6pcm->out.urbs[index])
+			break;
+
+	if (index >= line6pcm->line6->iso_buffers)
+		return;		/* URB has been unlinked asynchronously */
+
+	for (i = 0; i < LINE6_ISO_PACKETS; i++)
+		length += urb->iso_frame_desc[i].length;
+
+	spin_lock_irqsave(&line6pcm->out.lock, flags);
+
+	if (test_bit(LINE6_STREAM_PCM, &line6pcm->out.running)) {
+		struct snd_pcm_runtime *runtime = substream->runtime;
+
+		line6pcm->out.pos_done +=
+		    length / bytes_per_frame;
+
+		if (line6pcm->out.pos_done >= runtime->buffer_size)
+			line6pcm->out.pos_done -= runtime->buffer_size;
+	}
+
+	clear_bit(index, &line6pcm->out.active_urbs);
+
+	for (i = 0; i < LINE6_ISO_PACKETS; i++)
+		if (urb->iso_frame_desc[i].status == -EXDEV) {
+			shutdown = 1;
+			break;
+		}
+
+	if (test_and_clear_bit(index, &line6pcm->out.unlink_urbs))
+		shutdown = 1;
+
+	if (!shutdown) {
+		submit_audio_out_urb(line6pcm);
+
+		if (test_bit(LINE6_STREAM_PCM, &line6pcm->out.running)) {
+			line6pcm->out.bytes += length;
+			if (line6pcm->out.bytes >= line6pcm->out.period) {
+				line6pcm->out.bytes %= line6pcm->out.period;
+				spin_unlock(&line6pcm->out.lock);
+				snd_pcm_period_elapsed(substream);
+				spin_lock(&line6pcm->out.lock);
+			}
+		}
+	}
+	spin_unlock_irqrestore(&line6pcm->out.lock, flags);
+}
+
+/* open playback callback */
+static int snd_line6_playback_open(struct snd_pcm_substream *substream)
+{
+	int err;
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_line6_pcm *line6pcm = snd_pcm_substream_chip(substream);
+
+	err = snd_pcm_hw_constraint_ratdens(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
+					    &line6pcm->properties->rates);
+	if (err < 0)
+		return err;
+
+	runtime->hw = line6pcm->properties->playback_hw;
+	return 0;
+}
+
+/* close playback callback */
+static int snd_line6_playback_close(struct snd_pcm_substream *substream)
+{
+	return 0;
+}
+
+/* playback operators */
+const struct snd_pcm_ops snd_line6_playback_ops = {
+	.open = snd_line6_playback_open,
+	.close = snd_line6_playback_close,
+	.hw_params = snd_line6_hw_params,
+	.hw_free = snd_line6_hw_free,
+	.prepare = snd_line6_prepare,
+	.trigger = snd_line6_trigger,
+	.pointer = snd_line6_pointer,
+};
+
+int line6_create_audio_out_urbs(struct snd_line6_pcm *line6pcm)
+{
+	struct usb_line6 *line6 = line6pcm->line6;
+	int i;
+
+	line6pcm->out.urbs = kzalloc_objs(struct urb *, line6->iso_buffers);
+	if (line6pcm->out.urbs == NULL)
+		return -ENOMEM;
+
+	/* create audio URBs and fill in constant values: */
+	for (i = 0; i < line6->iso_buffers; ++i) {
+		struct urb *urb;
+
+		/* URB for audio out: */
+		urb = line6pcm->out.urbs[i] =
+		    usb_alloc_urb(LINE6_ISO_PACKETS, GFP_KERNEL);
+
+		if (urb == NULL)
+			return -ENOMEM;
+
+		urb->dev = line6->usbdev;
+		urb->pipe =
+		    usb_sndisocpipe(line6->usbdev,
+				    line6->properties->ep_audio_w &
+				    USB_ENDPOINT_NUMBER_MASK);
+		urb->transfer_flags = URB_ISO_ASAP;
+		urb->start_frame = -1;
+		urb->number_of_packets = LINE6_ISO_PACKETS;
+		urb->interval = LINE6_ISO_INTERVAL;
+		urb->error_count = 0;
+		urb->complete = audio_out_callback;
+		if (usb_urb_ep_type_check(urb))
+			return -EINVAL;
+	}
+
+	return 0;
+}
diff --git a/sound/usb/line6/playback.h b/sound/usb/line6/playback.h
new file mode 100644
index 000000000..2e0ec0ade
--- /dev/null
+++ b/sound/usb/line6/playback.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#ifndef PLAYBACK_H
+#define PLAYBACK_H
+
+#include <sound/pcm.h>
+
+#include "driver.h"
+
+/*
+ * When the TonePort is used with jack in full duplex mode and the outputs are
+ * not connected, the software monitor produces an ugly noise since everything
+ * written to the output buffer (i.e., the input signal) will be repeated in
+ * the next period (sounds like a delay effect). As a workaround, the output
+ * buffer is cleared after the data have been read, but there must be a better
+ * solution. Until one is found, this workaround can be used to fix the
+ * problem.
+ */
+#define USE_CLEAR_BUFFER_WORKAROUND 1
+
+extern const struct snd_pcm_ops snd_line6_playback_ops;
+
+extern int line6_create_audio_out_urbs(struct snd_line6_pcm *line6pcm);
+extern int line6_submit_audio_out_all_urbs(struct snd_line6_pcm *line6pcm);
+
+#endif
diff --git a/sound/usb/line6/pod.c b/sound/usb/line6/pod.c
new file mode 100644
index 000000000..6f948c3e8
--- /dev/null
+++ b/sound/usb/line6/pod.c
@@ -0,0 +1,542 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+
+#include "capture.h"
+#include "driver.h"
+#include "playback.h"
+
+/*
+	Locate name in binary program dump
+*/
+#define	POD_NAME_OFFSET 0
+#define	POD_NAME_LENGTH 16
+
+/*
+	Other constants
+*/
+#define POD_CONTROL_SIZE 0x80
+#define POD_BUFSIZE_DUMPREQ 7
+#define POD_STARTUP_DELAY 1000
+
+/*
+	Stages of POD startup procedure
+*/
+enum {
+	POD_STARTUP_VERSIONREQ,
+	POD_STARTUP_SETUP,
+	POD_STARTUP_DONE,
+};
+
+enum {
+	LINE6_BASSPODXT,
+	LINE6_BASSPODXTLIVE,
+	LINE6_BASSPODXTPRO,
+	LINE6_POCKETPOD,
+	LINE6_PODXT,
+	LINE6_PODXTLIVE_POD,
+	LINE6_PODXTPRO,
+};
+
+struct usb_line6_pod {
+	/* Generic Line 6 USB data */
+	struct usb_line6 line6;
+
+	/* Instrument monitor level */
+	int monitor_level;
+
+	/* Current progress in startup procedure */
+	int startup_progress;
+
+	/* Serial number of device */
+	u32 serial_number;
+
+	/* Firmware version (x 100) */
+	int firmware_version;
+
+	/* Device ID */
+	int device_id;
+};
+
+#define line6_to_pod(x)		container_of(x, struct usb_line6_pod, line6)
+
+#define POD_SYSEX_CODE 3
+
+/* *INDENT-OFF* */
+
+enum {
+	POD_SYSEX_SAVE      = 0x24,
+	POD_SYSEX_SYSTEM    = 0x56,
+	POD_SYSEX_SYSTEMREQ = 0x57,
+	/* POD_SYSEX_UPDATE    = 0x6c, */  /* software update! */
+	POD_SYSEX_STORE     = 0x71,
+	POD_SYSEX_FINISH    = 0x72,
+	POD_SYSEX_DUMPMEM   = 0x73,
+	POD_SYSEX_DUMP      = 0x74,
+	POD_SYSEX_DUMPREQ   = 0x75
+
+	/* dumps entire internal memory of PODxt Pro */
+	/* POD_SYSEX_DUMPMEM2  = 0x76 */
+};
+
+enum {
+	POD_MONITOR_LEVEL  = 0x04,
+	POD_SYSTEM_INVALID = 0x10000
+};
+
+/* *INDENT-ON* */
+
+enum {
+	POD_DUMP_MEMORY = 2
+};
+
+enum {
+	POD_BUSY_READ,
+	POD_BUSY_WRITE,
+	POD_CHANNEL_DIRTY,
+	POD_SAVE_PRESSED,
+	POD_BUSY_MIDISEND
+};
+
+static const struct snd_ratden pod_ratden = {
+	.num_min = 78125,
+	.num_max = 78125,
+	.num_step = 1,
+	.den = 2
+};
+
+static struct line6_pcm_properties pod_pcm_properties = {
+	.playback_hw = {
+				  .info = (SNDRV_PCM_INFO_MMAP |
+					   SNDRV_PCM_INFO_INTERLEAVED |
+					   SNDRV_PCM_INFO_BLOCK_TRANSFER |
+					   SNDRV_PCM_INFO_MMAP_VALID |
+					   SNDRV_PCM_INFO_PAUSE |
+					   SNDRV_PCM_INFO_SYNC_START),
+				  .formats = SNDRV_PCM_FMTBIT_S24_3LE,
+				  .rates = SNDRV_PCM_RATE_KNOT,
+				  .rate_min = 39062,
+				  .rate_max = 39063,
+				  .channels_min = 2,
+				  .channels_max = 2,
+				  .buffer_bytes_max = 60000,
+				  .period_bytes_min = 64,
+				  .period_bytes_max = 8192,
+				  .periods_min = 1,
+				  .periods_max = 1024},
+	.capture_hw = {
+				 .info = (SNDRV_PCM_INFO_MMAP |
+					  SNDRV_PCM_INFO_INTERLEAVED |
+					  SNDRV_PCM_INFO_BLOCK_TRANSFER |
+					  SNDRV_PCM_INFO_MMAP_VALID |
+					  SNDRV_PCM_INFO_SYNC_START),
+				 .formats = SNDRV_PCM_FMTBIT_S24_3LE,
+				 .rates = SNDRV_PCM_RATE_KNOT,
+				 .rate_min = 39062,
+				 .rate_max = 39063,
+				 .channels_min = 2,
+				 .channels_max = 2,
+				 .buffer_bytes_max = 60000,
+				 .period_bytes_min = 64,
+				 .period_bytes_max = 8192,
+				 .periods_min = 1,
+				 .periods_max = 1024},
+	.rates = {
+			    .nrats = 1,
+			    .rats = &pod_ratden},
+	.bytes_per_channel = 3 /* SNDRV_PCM_FMTBIT_S24_3LE */
+};
+
+
+static const char pod_version_header[] = {
+	0xf0, 0x7e, 0x7f, 0x06, 0x02
+};
+
+static char *pod_alloc_sysex_buffer(struct usb_line6_pod *pod, int code,
+				    int size)
+{
+	return line6_alloc_sysex_buffer(&pod->line6, POD_SYSEX_CODE, code,
+					size);
+}
+
+/*
+	Process a completely received message.
+*/
+static void line6_pod_process_message(struct usb_line6 *line6)
+{
+	struct usb_line6_pod *pod = line6_to_pod(line6);
+	const unsigned char *buf = pod->line6.buffer_message;
+
+	if (memcmp(buf, pod_version_header, sizeof(pod_version_header)) == 0) {
+		pod->firmware_version = buf[13] * 100 + buf[14] * 10 + buf[15];
+		pod->device_id = ((int)buf[8] << 16) | ((int)buf[9] << 8) |
+				 (int) buf[10];
+		if (pod->startup_progress == POD_STARTUP_VERSIONREQ) {
+			pod->startup_progress = POD_STARTUP_SETUP;
+			schedule_delayed_work(&line6->startup_work, 0);
+		}
+		return;
+	}
+
+	/* Only look for sysex messages from this device */
+	if (buf[0] != (LINE6_SYSEX_BEGIN | LINE6_CHANNEL_DEVICE) &&
+	    buf[0] != (LINE6_SYSEX_BEGIN | LINE6_CHANNEL_UNKNOWN)) {
+		return;
+	}
+	if (memcmp(buf + 1, line6_midi_id, sizeof(line6_midi_id)) != 0)
+		return;
+
+	if (buf[5] == POD_SYSEX_SYSTEM && buf[6] == POD_MONITOR_LEVEL) {
+		short value = ((int)buf[7] << 12) | ((int)buf[8] << 8) |
+			      ((int)buf[9] << 4) | (int)buf[10];
+		pod->monitor_level = value;
+	}
+}
+
+/*
+	Send system parameter (from integer).
+*/
+static int pod_set_system_param_int(struct usb_line6_pod *pod, int value,
+				    int code)
+{
+	char *sysex;
+	static const int size = 5;
+
+	sysex = pod_alloc_sysex_buffer(pod, POD_SYSEX_SYSTEM, size);
+	if (!sysex)
+		return -ENOMEM;
+	sysex[SYSEX_DATA_OFS] = code;
+	sysex[SYSEX_DATA_OFS + 1] = (value >> 12) & 0x0f;
+	sysex[SYSEX_DATA_OFS + 2] = (value >> 8) & 0x0f;
+	sysex[SYSEX_DATA_OFS + 3] = (value >> 4) & 0x0f;
+	sysex[SYSEX_DATA_OFS + 4] = (value) & 0x0f;
+	line6_send_sysex_message(&pod->line6, sysex, size);
+	kfree(sysex);
+	return 0;
+}
+
+/*
+	"read" request on "serial_number" special file.
+*/
+static ssize_t serial_number_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct snd_card *card = dev_to_snd_card(dev);
+	struct usb_line6_pod *pod = card->private_data;
+
+	return sysfs_emit(buf, "%u\n", pod->serial_number);
+}
+
+/*
+	"read" request on "firmware_version" special file.
+*/
+static ssize_t firmware_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct snd_card *card = dev_to_snd_card(dev);
+	struct usb_line6_pod *pod = card->private_data;
+
+	return sysfs_emit(buf, "%d.%02d\n", pod->firmware_version / 100,
+			  pod->firmware_version % 100);
+}
+
+/*
+	"read" request on "device_id" special file.
+*/
+static ssize_t device_id_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct snd_card *card = dev_to_snd_card(dev);
+	struct usb_line6_pod *pod = card->private_data;
+
+	return sysfs_emit(buf, "%d\n", pod->device_id);
+}
+
+/*
+	POD startup procedure.
+	This is a sequence of functions with special requirements (e.g., must
+	not run immediately after initialization, must not run in interrupt
+	context). After the last one has finished, the device is ready to use.
+*/
+
+static void pod_startup(struct usb_line6 *line6)
+{
+	struct usb_line6_pod *pod = line6_to_pod(line6);
+
+	switch (pod->startup_progress) {
+	case POD_STARTUP_VERSIONREQ:
+		/* request firmware version: */
+		line6_version_request_async(line6);
+		break;
+	case POD_STARTUP_SETUP:
+		/* serial number: */
+		line6_read_serial_number(&pod->line6, &pod->serial_number);
+
+		/* ALSA audio interface: */
+		if (snd_card_register(line6->card))
+			dev_err(line6->ifcdev, "Failed to register POD card.\n");
+		pod->startup_progress = POD_STARTUP_DONE;
+		break;
+	default:
+		break;
+	}
+}
+
+/* POD special files: */
+static DEVICE_ATTR_RO(device_id);
+static DEVICE_ATTR_RO(firmware_version);
+static DEVICE_ATTR_RO(serial_number);
+
+static struct attribute *pod_dev_attrs[] = {
+	&dev_attr_device_id.attr,
+	&dev_attr_firmware_version.attr,
+	&dev_attr_serial_number.attr,
+	NULL
+};
+
+static const struct attribute_group pod_dev_attr_group = {
+	.name = "pod",
+	.attrs = pod_dev_attrs,
+};
+
+/* control info callback */
+static int snd_pod_control_monitor_info(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 65535;
+	return 0;
+}
+
+/* control get callback */
+static int snd_pod_control_monitor_get(struct snd_kcontrol *kcontrol,
+				       struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	struct usb_line6_pod *pod = line6_to_pod(line6pcm->line6);
+
+	ucontrol->value.integer.value[0] = pod->monitor_level;
+	return 0;
+}
+
+/* control put callback */
+static int snd_pod_control_monitor_put(struct snd_kcontrol *kcontrol,
+				       struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	struct usb_line6_pod *pod = line6_to_pod(line6pcm->line6);
+
+	if (ucontrol->value.integer.value[0] == pod->monitor_level)
+		return 0;
+
+	pod->monitor_level = ucontrol->value.integer.value[0];
+	pod_set_system_param_int(pod, ucontrol->value.integer.value[0],
+				 POD_MONITOR_LEVEL);
+	return 1;
+}
+
+/* control definition */
+static const struct snd_kcontrol_new pod_control_monitor = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Monitor Playback Volume",
+	.index = 0,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.info = snd_pod_control_monitor_info,
+	.get = snd_pod_control_monitor_get,
+	.put = snd_pod_control_monitor_put
+};
+
+/*
+	 Try to init POD device.
+*/
+static int pod_init(struct usb_line6 *line6,
+		    const struct usb_device_id *id)
+{
+	int err;
+	struct usb_line6_pod *pod = line6_to_pod(line6);
+
+	line6->process_message = line6_pod_process_message;
+	line6->startup = pod_startup;
+
+	/* create sysfs entries: */
+	err = snd_card_add_dev_attr(line6->card, &pod_dev_attr_group);
+	if (err < 0)
+		return err;
+
+	/* initialize PCM subsystem: */
+	err = line6_init_pcm(line6, &pod_pcm_properties);
+	if (err < 0)
+		return err;
+
+	/* register monitor control: */
+	err = snd_ctl_add(line6->card,
+			  snd_ctl_new1(&pod_control_monitor, line6->line6pcm));
+	if (err < 0)
+		return err;
+
+	/*
+	   When the sound card is registered at this point, the PODxt Live
+	   displays "Invalid Code Error 07", so we do it later in the event
+	   handler.
+	 */
+
+	if (pod->line6.properties->capabilities & LINE6_CAP_CONTROL) {
+		pod->monitor_level = POD_SYSTEM_INVALID;
+
+		/* initiate startup procedure: */
+		schedule_delayed_work(&line6->startup_work,
+				      msecs_to_jiffies(POD_STARTUP_DELAY));
+	}
+
+	return 0;
+}
+
+#define LINE6_DEVICE(prod) USB_DEVICE(0x0e41, prod)
+#define LINE6_IF_NUM(prod, n) USB_DEVICE_INTERFACE_NUMBER(0x0e41, prod, n)
+
+/* table of devices that work with this driver */
+static const struct usb_device_id pod_id_table[] = {
+	{ LINE6_DEVICE(0x4250),    .driver_info = LINE6_BASSPODXT },
+	{ LINE6_DEVICE(0x4642),    .driver_info = LINE6_BASSPODXTLIVE },
+	{ LINE6_DEVICE(0x4252),    .driver_info = LINE6_BASSPODXTPRO },
+	{ LINE6_IF_NUM(0x5051, 1), .driver_info = LINE6_POCKETPOD },
+	{ LINE6_DEVICE(0x5044),    .driver_info = LINE6_PODXT },
+	{ LINE6_IF_NUM(0x4650, 0), .driver_info = LINE6_PODXTLIVE_POD },
+	{ LINE6_DEVICE(0x5050),    .driver_info = LINE6_PODXTPRO },
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, pod_id_table);
+
+static const struct line6_properties pod_properties_table[] = {
+	[LINE6_BASSPODXT] = {
+		.id = "BassPODxt",
+		.name = "BassPODxt",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI
+				| LINE6_CAP_PCM
+				| LINE6_CAP_HWMON,
+		.altsetting = 5,
+		.ep_ctrl_r = 0x84,
+		.ep_ctrl_w = 0x03,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_BASSPODXTLIVE] = {
+		.id = "BassPODxtLive",
+		.name = "BassPODxt Live",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI
+				| LINE6_CAP_PCM
+				| LINE6_CAP_HWMON,
+		.altsetting = 1,
+		.ep_ctrl_r = 0x84,
+		.ep_ctrl_w = 0x03,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_BASSPODXTPRO] = {
+		.id = "BassPODxtPro",
+		.name = "BassPODxt Pro",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI
+				| LINE6_CAP_PCM
+				| LINE6_CAP_HWMON,
+		.altsetting = 5,
+		.ep_ctrl_r = 0x84,
+		.ep_ctrl_w = 0x03,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_POCKETPOD] = {
+		.id = "PocketPOD",
+		.name = "Pocket POD",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI,
+		.altsetting = 0,
+		.ep_ctrl_r = 0x82,
+		.ep_ctrl_w = 0x02,
+		/* no audio channel */
+	},
+	[LINE6_PODXT] = {
+		.id = "PODxt",
+		.name = "PODxt",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI
+				| LINE6_CAP_PCM
+				| LINE6_CAP_HWMON,
+		.altsetting = 5,
+		.ep_ctrl_r = 0x84,
+		.ep_ctrl_w = 0x03,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_PODXTLIVE_POD] = {
+		.id = "PODxtLive",
+		.name = "PODxt Live",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI
+				| LINE6_CAP_PCM
+				| LINE6_CAP_HWMON,
+		.altsetting = 1,
+		.ep_ctrl_r = 0x84,
+		.ep_ctrl_w = 0x03,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_PODXTPRO] = {
+		.id = "PODxtPro",
+		.name = "PODxt Pro",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI
+				| LINE6_CAP_PCM
+				| LINE6_CAP_HWMON,
+		.altsetting = 5,
+		.ep_ctrl_r = 0x84,
+		.ep_ctrl_w = 0x03,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+};
+
+/*
+	Probe USB device.
+*/
+static int pod_probe(struct usb_interface *interface,
+		     const struct usb_device_id *id)
+{
+	return line6_probe(interface, id, "Line6-POD",
+			   &pod_properties_table[id->driver_info],
+			   pod_init, sizeof(struct usb_line6_pod));
+}
+
+static struct usb_driver pod_driver = {
+	.name = KBUILD_MODNAME,
+	.probe = pod_probe,
+	.disconnect = line6_disconnect,
+#ifdef CONFIG_PM
+	.suspend = line6_suspend,
+	.resume = line6_resume,
+	.reset_resume = line6_resume,
+#endif
+	.id_table = pod_id_table,
+};
+
+module_usb_driver(pod_driver);
+
+MODULE_DESCRIPTION("Line 6 POD USB driver");
+MODULE_LICENSE("GPL");
diff --git a/sound/usb/line6/podhd.c b/sound/usb/line6/podhd.c
new file mode 100644
index 000000000..841b64479
--- /dev/null
+++ b/sound/usb/line6/podhd.c
@@ -0,0 +1,587 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Pod HD
+ *
+ * Copyright (C) 2011 Stefan Hajnoczi <stefanha@gmail.com>
+ * Copyright (C) 2015 Andrej Krutak <dev@andree.sk>
+ * Copyright (C) 2017 Hans P. Moller <hmoller@uc.cl>
+ */
+
+#include <linux/usb.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/pcm.h>
+
+#include "driver.h"
+#include "pcm.h"
+
+#define PODHD_STARTUP_DELAY 500
+
+enum {
+	LINE6_PODHD300,
+	LINE6_PODHD400,
+	LINE6_PODHD500,
+	LINE6_PODX3,
+	LINE6_PODX3LIVE,
+	LINE6_PODHD500X,
+	LINE6_PODHDDESKTOP,
+	LINE6_PODHDPROX,
+	LINE6_PODHDPRO,
+};
+
+struct usb_line6_podhd {
+	/* Generic Line 6 USB data */
+	struct usb_line6 line6;
+
+	/* Serial number of device */
+	u32 serial_number;
+
+	/* Firmware version */
+	int firmware_version;
+
+	/* Monitor level */
+	int monitor_level;
+};
+
+#define line6_to_podhd(x)	container_of(x, struct usb_line6_podhd, line6)
+
+static const struct snd_ratden podhd_ratden = {
+	.num_min = 48000,
+	.num_max = 48000,
+	.num_step = 1,
+	.den = 1,
+};
+
+static struct line6_pcm_properties podhd_pcm_properties = {
+	.playback_hw = {
+				  .info = (SNDRV_PCM_INFO_MMAP |
+					   SNDRV_PCM_INFO_INTERLEAVED |
+					   SNDRV_PCM_INFO_BLOCK_TRANSFER |
+					   SNDRV_PCM_INFO_MMAP_VALID |
+					   SNDRV_PCM_INFO_PAUSE |
+					   SNDRV_PCM_INFO_SYNC_START),
+				  .formats = SNDRV_PCM_FMTBIT_S24_3LE,
+				  .rates = SNDRV_PCM_RATE_48000,
+				  .rate_min = 48000,
+				  .rate_max = 48000,
+				  .channels_min = 2,
+				  .channels_max = 2,
+				  .buffer_bytes_max = 60000,
+				  .period_bytes_min = 64,
+				  .period_bytes_max = 8192,
+				  .periods_min = 1,
+				  .periods_max = 1024},
+	.capture_hw = {
+				 .info = (SNDRV_PCM_INFO_MMAP |
+					  SNDRV_PCM_INFO_INTERLEAVED |
+					  SNDRV_PCM_INFO_BLOCK_TRANSFER |
+					  SNDRV_PCM_INFO_MMAP_VALID |
+					  SNDRV_PCM_INFO_SYNC_START),
+				 .formats = SNDRV_PCM_FMTBIT_S24_3LE,
+				 .rates = SNDRV_PCM_RATE_48000,
+				 .rate_min = 48000,
+				 .rate_max = 48000,
+				 .channels_min = 2,
+				 .channels_max = 2,
+				 .buffer_bytes_max = 60000,
+				 .period_bytes_min = 64,
+				 .period_bytes_max = 8192,
+				 .periods_min = 1,
+				 .periods_max = 1024},
+	.rates = {
+			    .nrats = 1,
+			    .rats = &podhd_ratden},
+	.bytes_per_channel = 3 /* SNDRV_PCM_FMTBIT_S24_3LE */
+};
+
+static struct line6_pcm_properties podx3_pcm_properties = {
+	.playback_hw = {
+				  .info = (SNDRV_PCM_INFO_MMAP |
+					   SNDRV_PCM_INFO_INTERLEAVED |
+					   SNDRV_PCM_INFO_BLOCK_TRANSFER |
+					   SNDRV_PCM_INFO_MMAP_VALID |
+					   SNDRV_PCM_INFO_PAUSE |
+					   SNDRV_PCM_INFO_SYNC_START),
+				  .formats = SNDRV_PCM_FMTBIT_S24_3LE,
+				  .rates = SNDRV_PCM_RATE_48000,
+				  .rate_min = 48000,
+				  .rate_max = 48000,
+				  .channels_min = 2,
+				  .channels_max = 2,
+				  .buffer_bytes_max = 60000,
+				  .period_bytes_min = 64,
+				  .period_bytes_max = 8192,
+				  .periods_min = 1,
+				  .periods_max = 1024},
+	.capture_hw = {
+				 .info = (SNDRV_PCM_INFO_MMAP |
+					  SNDRV_PCM_INFO_INTERLEAVED |
+					  SNDRV_PCM_INFO_BLOCK_TRANSFER |
+					  SNDRV_PCM_INFO_MMAP_VALID |
+					  SNDRV_PCM_INFO_SYNC_START),
+				 .formats = SNDRV_PCM_FMTBIT_S24_3LE,
+				 .rates = SNDRV_PCM_RATE_48000,
+				 .rate_min = 48000,
+				 .rate_max = 48000,
+				 /* 1+2: Main signal (out), 3+4: Tone 1,
+				  * 5+6: Tone 2, 7+8: raw
+				  */
+				 .channels_min = 8,
+				 .channels_max = 8,
+				 .buffer_bytes_max = 60000,
+				 .period_bytes_min = 64,
+				 .period_bytes_max = 8192,
+				 .periods_min = 1,
+				 .periods_max = 1024},
+	.rates = {
+			    .nrats = 1,
+			    .rats = &podhd_ratden},
+	.bytes_per_channel = 3 /* SNDRV_PCM_FMTBIT_S24_3LE */
+};
+static struct usb_driver podhd_driver;
+
+static ssize_t serial_number_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct snd_card *card = dev_to_snd_card(dev);
+	struct usb_line6_podhd *pod = card->private_data;
+
+	return sysfs_emit(buf, "%u\n", pod->serial_number);
+}
+
+static ssize_t firmware_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct snd_card *card = dev_to_snd_card(dev);
+	struct usb_line6_podhd *pod = card->private_data;
+
+	return sysfs_emit(buf, "%06x\n", pod->firmware_version);
+}
+
+static DEVICE_ATTR_RO(firmware_version);
+static DEVICE_ATTR_RO(serial_number);
+
+static struct attribute *podhd_dev_attrs[] = {
+	&dev_attr_firmware_version.attr,
+	&dev_attr_serial_number.attr,
+	NULL
+};
+
+static const struct attribute_group podhd_dev_attr_group = {
+	.name = "podhd",
+	.attrs = podhd_dev_attrs,
+};
+
+/*
+ * POD X3 startup procedure.
+ *
+ * May be compatible with other POD HD's, since it's also similar to the
+ * previous POD setup. In any case, it doesn't seem to be required for the
+ * audio nor bulk interfaces to work.
+ */
+
+static int podhd_dev_start(struct usb_line6_podhd *pod)
+{
+	int ret;
+	u8 init_bytes[8];
+	int i;
+	struct usb_device *usbdev = pod->line6.usbdev;
+
+	ret = usb_control_msg_send(usbdev, 0,
+					0x67, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+					0x11, 0,
+					NULL, 0, LINE6_TIMEOUT, GFP_KERNEL);
+	if (ret) {
+		dev_err(pod->line6.ifcdev, "read request failed (error %d)\n", ret);
+		goto exit;
+	}
+
+	/* NOTE: looks like some kind of ping message */
+	ret = usb_control_msg_recv(usbdev, 0, 0x67,
+					USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+					0x11, 0x0,
+					init_bytes, 3, LINE6_TIMEOUT, GFP_KERNEL);
+	if (ret) {
+		dev_err(pod->line6.ifcdev,
+			"receive length failed (error %d)\n", ret);
+		goto exit;
+	}
+
+	pod->firmware_version =
+		(init_bytes[0] << 16) | (init_bytes[1] << 8) | (init_bytes[2] << 0);
+
+	for (i = 0; i <= 16; i++) {
+		ret = line6_read_data(&pod->line6, 0xf000 + 0x08 * i, init_bytes, 8);
+		if (ret < 0)
+			goto exit;
+	}
+
+	ret = usb_control_msg_send(usbdev, 0,
+					USB_REQ_SET_FEATURE,
+					USB_TYPE_STANDARD | USB_RECIP_DEVICE | USB_DIR_OUT,
+					1, 0,
+					NULL, 0, LINE6_TIMEOUT, GFP_KERNEL);
+exit:
+	return ret;
+}
+
+static void podhd_startup(struct usb_line6 *line6)
+{
+	struct usb_line6_podhd *pod = line6_to_podhd(line6);
+
+	podhd_dev_start(pod);
+	line6_read_serial_number(&pod->line6, &pod->serial_number);
+	if (snd_card_register(line6->card))
+		dev_err(line6->ifcdev, "Failed to register POD HD card.\n");
+}
+
+static void podhd_disconnect(struct usb_line6 *line6)
+{
+	struct usb_line6_podhd *pod = line6_to_podhd(line6);
+
+	if (pod->line6.properties->capabilities & LINE6_CAP_CONTROL_INFO) {
+		struct usb_interface *intf;
+
+		intf = usb_ifnum_to_if(line6->usbdev,
+					pod->line6.properties->ctrl_if);
+		if (intf)
+			usb_driver_release_interface(&podhd_driver, intf);
+	}
+}
+
+static const unsigned int float_zero_to_one_lookup[] = {
+0x00000000, 0x3c23d70a, 0x3ca3d70a, 0x3cf5c28f, 0x3d23d70a, 0x3d4ccccd,
+0x3d75c28f, 0x3d8f5c29, 0x3da3d70a, 0x3db851ec, 0x3dcccccd, 0x3de147ae,
+0x3df5c28f, 0x3e051eb8, 0x3e0f5c29, 0x3e19999a, 0x3e23d70a, 0x3e2e147b,
+0x3e3851ec, 0x3e428f5c, 0x3e4ccccd, 0x3e570a3d, 0x3e6147ae, 0x3e6b851f,
+0x3e75c28f, 0x3e800000, 0x3e851eb8, 0x3e8a3d71, 0x3e8f5c29, 0x3e947ae1,
+0x3e99999a, 0x3e9eb852, 0x3ea3d70a, 0x3ea8f5c3, 0x3eae147b, 0x3eb33333,
+0x3eb851ec, 0x3ebd70a4, 0x3ec28f5c, 0x3ec7ae14, 0x3ecccccd, 0x3ed1eb85,
+0x3ed70a3d, 0x3edc28f6, 0x3ee147ae, 0x3ee66666, 0x3eeb851f, 0x3ef0a3d7,
+0x3ef5c28f, 0x3efae148, 0x3f000000, 0x3f028f5c, 0x3f051eb8, 0x3f07ae14,
+0x3f0a3d71, 0x3f0ccccd, 0x3f0f5c29, 0x3f11eb85, 0x3f147ae1, 0x3f170a3d,
+0x3f19999a, 0x3f1c28f6, 0x3f1eb852, 0x3f2147ae, 0x3f23d70a, 0x3f266666,
+0x3f28f5c3, 0x3f2b851f, 0x3f2e147b, 0x3f30a3d7, 0x3f333333, 0x3f35c28f,
+0x3f3851ec, 0x3f3ae148, 0x3f3d70a4, 0x3f400000, 0x3f428f5c, 0x3f451eb8,
+0x3f47ae14, 0x3f4a3d71, 0x3f4ccccd, 0x3f4f5c29, 0x3f51eb85, 0x3f547ae1,
+0x3f570a3d, 0x3f59999a, 0x3f5c28f6, 0x3f5eb852, 0x3f6147ae, 0x3f63d70a,
+0x3f666666, 0x3f68f5c3, 0x3f6b851f, 0x3f6e147b, 0x3f70a3d7, 0x3f733333,
+0x3f75c28f, 0x3f7851ec, 0x3f7ae148, 0x3f7d70a4, 0x3f800000
+};
+
+static void podhd_set_monitor_level(struct usb_line6_podhd *podhd, int value)
+{
+	unsigned int fl;
+	static const unsigned char msg[16] = {
+		/* Chunk is 0xc bytes (without first word) */
+		0x0c, 0x00,
+		/* First chunk in the message */
+		0x01, 0x00,
+		/* Message size is 2 4-byte words */
+		0x02, 0x00,
+		/* Unknown */
+		0x04, 0x41,
+		/* Unknown */
+		0x04, 0x00, 0x13, 0x00,
+		/* Volume, LE float32, 0.0 - 1.0 */
+		0x00, 0x00, 0x00, 0x00
+	};
+	unsigned char *buf;
+
+	buf = kmemdup(msg, sizeof(msg), GFP_KERNEL);
+	if (!buf)
+		return;
+
+	if (value < 0)
+		value = 0;
+
+	if (value >= ARRAY_SIZE(float_zero_to_one_lookup))
+		value = ARRAY_SIZE(float_zero_to_one_lookup) - 1;
+
+	fl = float_zero_to_one_lookup[value];
+
+	buf[12] = (fl >> 0) & 0xff;
+	buf[13] = (fl >> 8) & 0xff;
+	buf[14] = (fl >> 16) & 0xff;
+	buf[15] = (fl >> 24) & 0xff;
+
+	line6_send_raw_message(&podhd->line6, buf, sizeof(msg));
+	kfree(buf);
+
+	podhd->monitor_level = value;
+}
+
+/* control info callback */
+static int snd_podhd_control_monitor_info(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 100;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+/* control get callback */
+static int snd_podhd_control_monitor_get(struct snd_kcontrol *kcontrol,
+				       struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	struct usb_line6_podhd *podhd = line6_to_podhd(line6pcm->line6);
+
+	ucontrol->value.integer.value[0] = podhd->monitor_level;
+	return 0;
+}
+
+/* control put callback */
+static int snd_podhd_control_monitor_put(struct snd_kcontrol *kcontrol,
+				       struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	struct usb_line6_podhd *podhd = line6_to_podhd(line6pcm->line6);
+
+	if (ucontrol->value.integer.value[0] == podhd->monitor_level)
+		return 0;
+
+	podhd_set_monitor_level(podhd, ucontrol->value.integer.value[0]);
+	return 1;
+}
+
+/* control definition */
+static const struct snd_kcontrol_new podhd_control_monitor = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Monitor Playback Volume",
+	.index = 0,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.info = snd_podhd_control_monitor_info,
+	.get = snd_podhd_control_monitor_get,
+	.put = snd_podhd_control_monitor_put
+};
+
+/*
+	Try to init POD HD device.
+*/
+static int podhd_init(struct usb_line6 *line6,
+		      const struct usb_device_id *id)
+{
+	int err;
+	struct usb_line6_podhd *pod = line6_to_podhd(line6);
+	struct usb_interface *intf;
+
+	line6->disconnect = podhd_disconnect;
+	line6->startup = podhd_startup;
+
+	if (pod->line6.properties->capabilities & LINE6_CAP_CONTROL) {
+		/* claim the data interface */
+		intf = usb_ifnum_to_if(line6->usbdev,
+					pod->line6.properties->ctrl_if);
+		if (!intf) {
+			dev_err(pod->line6.ifcdev, "interface %d not found\n",
+				pod->line6.properties->ctrl_if);
+			return -ENODEV;
+		}
+
+		err = usb_driver_claim_interface(&podhd_driver, intf, NULL);
+		if (err != 0) {
+			dev_err(pod->line6.ifcdev, "can't claim interface %d, error %d\n",
+				pod->line6.properties->ctrl_if, err);
+			return err;
+		}
+	}
+
+	if (pod->line6.properties->capabilities & LINE6_CAP_CONTROL_INFO) {
+		/* create sysfs entries: */
+		err = snd_card_add_dev_attr(line6->card, &podhd_dev_attr_group);
+		if (err < 0)
+			return err;
+	}
+
+	if (pod->line6.properties->capabilities & LINE6_CAP_PCM) {
+		/* initialize PCM subsystem: */
+		err = line6_init_pcm(line6,
+			(id->driver_info == LINE6_PODX3 ||
+			id->driver_info == LINE6_PODX3LIVE) ? &podx3_pcm_properties :
+			&podhd_pcm_properties);
+		if (err < 0)
+			return err;
+	}
+
+	if (pod->line6.properties->capabilities & LINE6_CAP_HWMON_CTL) {
+		podhd_set_monitor_level(pod, 100);
+		err = snd_ctl_add(line6->card,
+				  snd_ctl_new1(&podhd_control_monitor,
+					       line6->line6pcm));
+		if (err < 0)
+			return err;
+	}
+
+	if (!(pod->line6.properties->capabilities & LINE6_CAP_CONTROL_INFO)) {
+		/* register USB audio system directly */
+		return snd_card_register(line6->card);
+	}
+
+	/* init device and delay registering */
+	schedule_delayed_work(&line6->startup_work,
+			      msecs_to_jiffies(PODHD_STARTUP_DELAY));
+	return 0;
+}
+
+#define LINE6_DEVICE(prod) USB_DEVICE(0x0e41, prod)
+#define LINE6_IF_NUM(prod, n) USB_DEVICE_INTERFACE_NUMBER(0x0e41, prod, n)
+
+/* table of devices that work with this driver */
+static const struct usb_device_id podhd_id_table[] = {
+	/* TODO: no need to alloc data interfaces when only audio is used */
+	{ LINE6_DEVICE(0x5057),    .driver_info = LINE6_PODHD300 },
+	{ LINE6_DEVICE(0x5058),    .driver_info = LINE6_PODHD400 },
+	{ LINE6_IF_NUM(0x414D, 0), .driver_info = LINE6_PODHD500 },
+	{ LINE6_IF_NUM(0x414A, 0), .driver_info = LINE6_PODX3 },
+	{ LINE6_IF_NUM(0x414B, 0), .driver_info = LINE6_PODX3LIVE },
+	{ LINE6_IF_NUM(0x4159, 0), .driver_info = LINE6_PODHD500X },
+	{ LINE6_IF_NUM(0x4156, 0), .driver_info = LINE6_PODHDDESKTOP },
+	{ LINE6_IF_NUM(0x415A, 0), .driver_info = LINE6_PODHDPROX },
+	{ LINE6_IF_NUM(0x4157, 0), .driver_info = LINE6_PODHDPRO },
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, podhd_id_table);
+
+static const struct line6_properties podhd_properties_table[] = {
+	[LINE6_PODHD300] = {
+		.id = "PODHD300",
+		.name = "POD HD300",
+		.capabilities	= LINE6_CAP_PCM
+				| LINE6_CAP_HWMON,
+		.altsetting = 5,
+		.ep_ctrl_r = 0x84,
+		.ep_ctrl_w = 0x03,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_PODHD400] = {
+		.id = "PODHD400",
+		.name = "POD HD400",
+		.capabilities	= LINE6_CAP_PCM
+				| LINE6_CAP_HWMON,
+		.altsetting = 5,
+		.ep_ctrl_r = 0x84,
+		.ep_ctrl_w = 0x03,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_PODHD500] = {
+		.id = "PODHD500",
+		.name = "POD HD500",
+		.capabilities	= LINE6_CAP_PCM | LINE6_CAP_CONTROL
+				| LINE6_CAP_HWMON | LINE6_CAP_HWMON_CTL,
+		.altsetting = 1,
+		.ctrl_if = 1,
+		.ep_ctrl_r = 0x81,
+		.ep_ctrl_w = 0x01,
+		.ep_audio_r = 0x86,
+		.ep_audio_w = 0x02,
+	},
+	[LINE6_PODX3] = {
+		.id = "PODX3",
+		.name = "POD X3",
+		.capabilities	= LINE6_CAP_CONTROL | LINE6_CAP_CONTROL_INFO
+				| LINE6_CAP_PCM | LINE6_CAP_HWMON | LINE6_CAP_IN_NEEDS_OUT,
+		.altsetting = 1,
+		.ep_ctrl_r = 0x81,
+		.ep_ctrl_w = 0x01,
+		.ctrl_if = 1,
+		.ep_audio_r = 0x86,
+		.ep_audio_w = 0x02,
+	},
+	[LINE6_PODX3LIVE] = {
+		.id = "PODX3LIVE",
+		.name = "POD X3 LIVE",
+		.capabilities	= LINE6_CAP_CONTROL | LINE6_CAP_CONTROL_INFO
+				| LINE6_CAP_PCM | LINE6_CAP_HWMON | LINE6_CAP_IN_NEEDS_OUT,
+		.altsetting = 1,
+		.ep_ctrl_r = 0x81,
+		.ep_ctrl_w = 0x01,
+		.ctrl_if = 1,
+		.ep_audio_r = 0x86,
+		.ep_audio_w = 0x02,
+	},
+	[LINE6_PODHD500X] = {
+		.id = "PODHD500X",
+		.name = "POD HD500X",
+		.capabilities	= LINE6_CAP_CONTROL | LINE6_CAP_HWMON_CTL
+				| LINE6_CAP_PCM | LINE6_CAP_HWMON,
+		.altsetting = 1,
+		.ep_ctrl_r = 0x81,
+		.ep_ctrl_w = 0x01,
+		.ctrl_if = 1,
+		.ep_audio_r = 0x86,
+		.ep_audio_w = 0x02,
+	},
+	[LINE6_PODHDDESKTOP] = {
+		.id = "PODHDDESKTOP",
+		.name = "POD HDDESKTOP",
+		.capabilities    = LINE6_CAP_CONTROL
+			| LINE6_CAP_PCM | LINE6_CAP_HWMON,
+		.altsetting = 1,
+		.ep_ctrl_r = 0x81,
+		.ep_ctrl_w = 0x01,
+		.ctrl_if = 1,
+		.ep_audio_r = 0x86,
+		.ep_audio_w = 0x02,
+	},
+	[LINE6_PODHDPROX] = {
+		.id = "PODHDPROX",
+		.name = "POD HD Pro X",
+		.capabilities	= LINE6_CAP_CONTROL | LINE6_CAP_CONTROL_INFO
+				| LINE6_CAP_PCM | LINE6_CAP_HWMON | LINE6_CAP_IN_NEEDS_OUT,
+		.altsetting = 1,
+		.ctrl_if = 1,
+		.ep_ctrl_r = 0x81,
+		.ep_ctrl_w = 0x01,
+		.ep_audio_r = 0x86,
+		.ep_audio_w = 0x02,
+	},
+	[LINE6_PODHDPRO] = {
+		.id = "PODHDPRO",
+		.name = "POD HD PRO",
+		.capabilities	= LINE6_CAP_PCM | LINE6_CAP_CONTROL
+				| LINE6_CAP_HWMON | LINE6_CAP_HWMON_CTL | LINE6_CAP_IN_NEEDS_OUT,
+		.altsetting = 1,
+		.ctrl_if = 1,
+		.ep_ctrl_r = 0x81,
+		.ep_ctrl_w = 0x01,
+		.ep_audio_r = 0x86,
+		.ep_audio_w = 0x02,
+	},
+};
+
+/*
+	Probe USB device.
+*/
+static int podhd_probe(struct usb_interface *interface,
+		       const struct usb_device_id *id)
+{
+	return line6_probe(interface, id, "Line6-PODHD",
+			   &podhd_properties_table[id->driver_info],
+			   podhd_init, sizeof(struct usb_line6_podhd));
+}
+
+static struct usb_driver podhd_driver = {
+	.name = KBUILD_MODNAME,
+	.probe = podhd_probe,
+	.disconnect = line6_disconnect,
+#ifdef CONFIG_PM
+	.suspend = line6_suspend,
+	.resume = line6_resume,
+	.reset_resume = line6_resume,
+#endif
+	.id_table = podhd_id_table,
+};
+
+module_usb_driver(podhd_driver);
+
+MODULE_DESCRIPTION("Line 6 PODHD USB driver");
+MODULE_LICENSE("GPL");
diff --git a/sound/usb/line6/toneport.c b/sound/usb/line6/toneport.c
new file mode 100644
index 000000000..1df5c0dcd
--- /dev/null
+++ b/sound/usb/line6/toneport.c
@@ -0,0 +1,582 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ *                         Emil Myhrman (emil.myhrman@gmail.com)
+ */
+
+#include <linux/wait.h>
+#include <linux/usb.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/leds.h>
+#include <sound/core.h>
+#include <sound/control.h>
+
+#include "capture.h"
+#include "driver.h"
+#include "playback.h"
+
+enum line6_device_type {
+	LINE6_GUITARPORT,
+	LINE6_PODSTUDIO_GX,
+	LINE6_PODSTUDIO_UX1,
+	LINE6_PODSTUDIO_UX2,
+	LINE6_TONEPORT_GX,
+	LINE6_TONEPORT_UX1,
+	LINE6_TONEPORT_UX2,
+};
+
+struct usb_line6_toneport;
+
+struct toneport_led {
+	struct led_classdev dev;
+	char name[64];
+	struct usb_line6_toneport *toneport;
+	bool registered;
+};
+
+struct usb_line6_toneport {
+	/* Generic Line 6 USB data */
+	struct usb_line6 line6;
+
+	/* Source selector */
+	int source;
+
+	/* Serial number of device */
+	u32 serial_number;
+
+	/* Firmware version (x 100) */
+	u8 firmware_version;
+
+	/* Device type */
+	enum line6_device_type type;
+
+	/* LED instances */
+	struct toneport_led leds[2];
+};
+
+#define line6_to_toneport(x) container_of(x, struct usb_line6_toneport, line6)
+
+static int toneport_send_cmd(struct usb_device *usbdev, int cmd1, int cmd2);
+
+#define TONEPORT_PCM_DELAY 1
+
+static const struct snd_ratden toneport_ratden = {
+	.num_min = 44100,
+	.num_max = 44100,
+	.num_step = 1,
+	.den = 1
+};
+
+static struct line6_pcm_properties toneport_pcm_properties = {
+	.playback_hw = {
+				  .info = (SNDRV_PCM_INFO_MMAP |
+					   SNDRV_PCM_INFO_INTERLEAVED |
+					   SNDRV_PCM_INFO_BLOCK_TRANSFER |
+					   SNDRV_PCM_INFO_MMAP_VALID |
+					   SNDRV_PCM_INFO_PAUSE |
+					   SNDRV_PCM_INFO_SYNC_START),
+				  .formats = SNDRV_PCM_FMTBIT_S16_LE,
+				  .rates = SNDRV_PCM_RATE_KNOT,
+				  .rate_min = 44100,
+				  .rate_max = 44100,
+				  .channels_min = 2,
+				  .channels_max = 2,
+				  .buffer_bytes_max = 60000,
+				  .period_bytes_min = 64,
+				  .period_bytes_max = 8192,
+				  .periods_min = 1,
+				  .periods_max = 1024},
+	.capture_hw = {
+				 .info = (SNDRV_PCM_INFO_MMAP |
+					  SNDRV_PCM_INFO_INTERLEAVED |
+					  SNDRV_PCM_INFO_BLOCK_TRANSFER |
+					  SNDRV_PCM_INFO_MMAP_VALID |
+					  SNDRV_PCM_INFO_SYNC_START),
+				 .formats = SNDRV_PCM_FMTBIT_S16_LE,
+				 .rates = SNDRV_PCM_RATE_KNOT,
+				 .rate_min = 44100,
+				 .rate_max = 44100,
+				 .channels_min = 2,
+				 .channels_max = 2,
+				 .buffer_bytes_max = 60000,
+				 .period_bytes_min = 64,
+				 .period_bytes_max = 8192,
+				 .periods_min = 1,
+				 .periods_max = 1024},
+	.rates = {
+			    .nrats = 1,
+			    .rats = &toneport_ratden},
+	.bytes_per_channel = 2
+};
+
+static const struct {
+	const char *name;
+	int code;
+} toneport_source_info[] = {
+	{"Microphone", 0x0a01},
+	{"Line", 0x0801},
+	{"Instrument", 0x0b01},
+	{"Inst & Mic", 0x0901}
+};
+
+static int toneport_send_cmd(struct usb_device *usbdev, int cmd1, int cmd2)
+{
+	int ret;
+
+	ret = usb_control_msg_send(usbdev, 0, 0x67,
+				   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+				   cmd1, cmd2, NULL, 0, LINE6_TIMEOUT,
+				   GFP_KERNEL);
+
+	if (ret) {
+		dev_err(&usbdev->dev, "send failed (error %d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* monitor info callback */
+static int snd_toneport_monitor_info(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 256;
+	return 0;
+}
+
+/* monitor get callback */
+static int snd_toneport_monitor_get(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+
+	ucontrol->value.integer.value[0] = line6pcm->volume_monitor;
+	return 0;
+}
+
+/* monitor put callback */
+static int snd_toneport_monitor_put(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	int err;
+
+	if (ucontrol->value.integer.value[0] == line6pcm->volume_monitor)
+		return 0;
+
+	line6pcm->volume_monitor = ucontrol->value.integer.value[0];
+
+	if (line6pcm->volume_monitor > 0) {
+		err = line6_pcm_acquire(line6pcm, LINE6_STREAM_MONITOR, true);
+		if (err < 0) {
+			line6pcm->volume_monitor = 0;
+			line6_pcm_release(line6pcm, LINE6_STREAM_MONITOR);
+			return err;
+		}
+	} else {
+		line6_pcm_release(line6pcm, LINE6_STREAM_MONITOR);
+	}
+
+	return 1;
+}
+
+/* source info callback */
+static int snd_toneport_source_info(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_info *uinfo)
+{
+	const int size = ARRAY_SIZE(toneport_source_info);
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
+	uinfo->count = 1;
+	uinfo->value.enumerated.items = size;
+
+	if (uinfo->value.enumerated.item >= size)
+		uinfo->value.enumerated.item = size - 1;
+
+	strscpy(uinfo->value.enumerated.name,
+	       toneport_source_info[uinfo->value.enumerated.item].name);
+
+	return 0;
+}
+
+/* source get callback */
+static int snd_toneport_source_get(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	struct usb_line6_toneport *toneport = line6_to_toneport(line6pcm->line6);
+
+	ucontrol->value.enumerated.item[0] = toneport->source;
+	return 0;
+}
+
+/* source put callback */
+static int snd_toneport_source_put(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_line6_pcm *line6pcm = snd_kcontrol_chip(kcontrol);
+	struct usb_line6_toneport *toneport = line6_to_toneport(line6pcm->line6);
+	unsigned int source;
+
+	source = ucontrol->value.enumerated.item[0];
+	if (source >= ARRAY_SIZE(toneport_source_info))
+		return -EINVAL;
+	if (source == toneport->source)
+		return 0;
+
+	toneport->source = source;
+	toneport_send_cmd(toneport->line6.usbdev,
+			  toneport_source_info[source].code, 0x0000);
+	return 1;
+}
+
+static void toneport_startup(struct usb_line6 *line6)
+{
+	line6_pcm_acquire(line6->line6pcm, LINE6_STREAM_MONITOR, true);
+}
+
+/* control definition */
+static const struct snd_kcontrol_new toneport_control_monitor = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Monitor Playback Volume",
+	.index = 0,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.info = snd_toneport_monitor_info,
+	.get = snd_toneport_monitor_get,
+	.put = snd_toneport_monitor_put
+};
+
+/* source selector definition */
+static const struct snd_kcontrol_new toneport_control_source = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "PCM Capture Source",
+	.index = 0,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.info = snd_toneport_source_info,
+	.get = snd_toneport_source_get,
+	.put = snd_toneport_source_put
+};
+
+/*
+	For the led on Guitarport.
+	Brightness goes from 0x00 to 0x26. Set a value above this to have led
+	blink.
+	(void cmd_0x02(byte red, byte green)
+*/
+
+static bool toneport_has_led(struct usb_line6_toneport *toneport)
+{
+	switch (toneport->type) {
+	case LINE6_GUITARPORT:
+	case LINE6_TONEPORT_GX:
+	/* add your device here if you are missing support for the LEDs */
+		return true;
+
+	default:
+		return false;
+	}
+}
+
+static const char * const toneport_led_colors[2] = { "red", "green" };
+static const int toneport_led_init_vals[2] = { 0x00, 0x26 };
+
+static void toneport_update_led(struct usb_line6_toneport *toneport)
+{
+	toneport_send_cmd(toneport->line6.usbdev,
+			  (toneport->leds[0].dev.brightness << 8) | 0x0002,
+			  toneport->leds[1].dev.brightness);
+}
+
+static void toneport_led_brightness_set(struct led_classdev *led_cdev,
+					enum led_brightness brightness)
+{
+	struct toneport_led *leds =
+		container_of(led_cdev, struct toneport_led, dev);
+	toneport_update_led(leds->toneport);
+}
+
+static int toneport_init_leds(struct usb_line6_toneport *toneport)
+{
+	struct device *dev = &toneport->line6.usbdev->dev;
+	int i, err;
+
+	for (i = 0; i < 2; i++) {
+		struct toneport_led *led = &toneport->leds[i];
+		struct led_classdev *leddev = &led->dev;
+
+		led->toneport = toneport;
+		snprintf(led->name, sizeof(led->name), "%s::%s",
+			 dev_name(dev), toneport_led_colors[i]);
+		leddev->name = led->name;
+		leddev->brightness = toneport_led_init_vals[i];
+		leddev->max_brightness = 0x26;
+		leddev->brightness_set = toneport_led_brightness_set;
+		err = led_classdev_register(dev, leddev);
+		if (err)
+			return err;
+		led->registered = true;
+	}
+
+	return 0;
+}
+
+static void toneport_remove_leds(struct usb_line6_toneport *toneport)
+{
+	struct toneport_led *led;
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		led = &toneport->leds[i];
+		if (!led->registered)
+			break;
+		led_classdev_unregister(&led->dev);
+		led->registered = false;
+	}
+}
+
+static bool toneport_has_source_select(struct usb_line6_toneport *toneport)
+{
+	switch (toneport->type) {
+	case LINE6_TONEPORT_UX1:
+	case LINE6_TONEPORT_UX2:
+	case LINE6_PODSTUDIO_UX1:
+	case LINE6_PODSTUDIO_UX2:
+		return true;
+
+	default:
+		return false;
+	}
+}
+
+/*
+	Setup Toneport device.
+*/
+static int toneport_setup(struct usb_line6_toneport *toneport)
+{
+	u32 *ticks;
+	struct usb_line6 *line6 = &toneport->line6;
+	struct usb_device *usbdev = line6->usbdev;
+
+	ticks = kmalloc_obj(*ticks);
+	if (!ticks)
+		return -ENOMEM;
+
+	/* sync time on device with host: */
+	/* note: 32-bit timestamps overflow in year 2106 */
+	*ticks = (u32)ktime_get_real_seconds();
+	line6_write_data(line6, 0x80c6, ticks, 4);
+	kfree(ticks);
+
+	/* enable device: */
+	toneport_send_cmd(usbdev, 0x0301, 0x0000);
+
+	/* initialize source select: */
+	if (toneport_has_source_select(toneport))
+		toneport_send_cmd(usbdev,
+				  toneport_source_info[toneport->source].code,
+				  0x0000);
+
+	if (toneport_has_led(toneport))
+		toneport_update_led(toneport);
+
+	schedule_delayed_work(&toneport->line6.startup_work,
+			      secs_to_jiffies(TONEPORT_PCM_DELAY));
+	return 0;
+}
+
+/*
+	Toneport device disconnected.
+*/
+static void line6_toneport_disconnect(struct usb_line6 *line6)
+{
+	struct usb_line6_toneport *toneport = line6_to_toneport(line6);
+
+	if (toneport_has_led(toneport))
+		toneport_remove_leds(toneport);
+}
+
+
+/*
+	 Try to init Toneport device.
+*/
+static int toneport_init(struct usb_line6 *line6,
+			 const struct usb_device_id *id)
+{
+	int err;
+	struct usb_line6_toneport *toneport = line6_to_toneport(line6);
+
+	toneport->type = id->driver_info;
+
+	line6->disconnect = line6_toneport_disconnect;
+	line6->startup = toneport_startup;
+
+	/* initialize PCM subsystem: */
+	err = line6_init_pcm(line6, &toneport_pcm_properties);
+	if (err < 0)
+		return err;
+
+	/* register monitor control: */
+	err = snd_ctl_add(line6->card,
+			  snd_ctl_new1(&toneport_control_monitor,
+				       line6->line6pcm));
+	if (err < 0)
+		return err;
+
+	/* register source select control: */
+	if (toneport_has_source_select(toneport)) {
+		err =
+		    snd_ctl_add(line6->card,
+				snd_ctl_new1(&toneport_control_source,
+					     line6->line6pcm));
+		if (err < 0)
+			return err;
+	}
+
+	line6_read_serial_number(line6, &toneport->serial_number);
+	line6_read_data(line6, 0x80c2, &toneport->firmware_version, 1);
+
+	if (toneport_has_led(toneport)) {
+		err = toneport_init_leds(toneport);
+		if (err < 0)
+			return err;
+	}
+
+	err = toneport_setup(toneport);
+	if (err)
+		return err;
+
+	/* register audio system: */
+	return snd_card_register(line6->card);
+}
+
+#ifdef CONFIG_PM
+/*
+	Resume Toneport device after reset.
+*/
+static int toneport_reset_resume(struct usb_interface *interface)
+{
+	int err;
+
+	err = toneport_setup(usb_get_intfdata(interface));
+	if (err)
+		return err;
+	return line6_resume(interface);
+}
+#endif
+
+#define LINE6_DEVICE(prod) USB_DEVICE(0x0e41, prod)
+#define LINE6_IF_NUM(prod, n) USB_DEVICE_INTERFACE_NUMBER(0x0e41, prod, n)
+
+/* table of devices that work with this driver */
+static const struct usb_device_id toneport_id_table[] = {
+	{ LINE6_DEVICE(0x4750),    .driver_info = LINE6_GUITARPORT },
+	{ LINE6_DEVICE(0x4153),    .driver_info = LINE6_PODSTUDIO_GX },
+	{ LINE6_DEVICE(0x4150),    .driver_info = LINE6_PODSTUDIO_UX1 },
+	{ LINE6_IF_NUM(0x4151, 0), .driver_info = LINE6_PODSTUDIO_UX2 },
+	{ LINE6_DEVICE(0x4147),    .driver_info = LINE6_TONEPORT_GX },
+	{ LINE6_DEVICE(0x4141),    .driver_info = LINE6_TONEPORT_UX1 },
+	{ LINE6_IF_NUM(0x4142, 0), .driver_info = LINE6_TONEPORT_UX2 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, toneport_id_table);
+
+static const struct line6_properties toneport_properties_table[] = {
+	[LINE6_GUITARPORT] = {
+		.id = "GuitarPort",
+		.name = "GuitarPort",
+		.capabilities	= LINE6_CAP_PCM,
+		.altsetting = 2,  /* 1..4 seem to be ok */
+		/* no control channel */
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_PODSTUDIO_GX] = {
+		.id = "PODStudioGX",
+		.name = "POD Studio GX",
+		.capabilities	= LINE6_CAP_PCM,
+		.altsetting = 2,  /* 1..4 seem to be ok */
+		/* no control channel */
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_PODSTUDIO_UX1] = {
+		.id = "PODStudioUX1",
+		.name = "POD Studio UX1",
+		.capabilities	= LINE6_CAP_PCM,
+		.altsetting = 2,  /* 1..4 seem to be ok */
+		/* no control channel */
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_PODSTUDIO_UX2] = {
+		.id = "PODStudioUX2",
+		.name = "POD Studio UX2",
+		.capabilities	= LINE6_CAP_PCM,
+		.altsetting = 2,  /* defaults to 44.1kHz, 16-bit */
+		/* no control channel */
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_TONEPORT_GX] = {
+		.id = "TonePortGX",
+		.name = "TonePort GX",
+		.capabilities	= LINE6_CAP_PCM,
+		.altsetting = 2,  /* 1..4 seem to be ok */
+		/* no control channel */
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_TONEPORT_UX1] = {
+		.id = "TonePortUX1",
+		.name = "TonePort UX1",
+		.capabilities	= LINE6_CAP_PCM,
+		.altsetting = 2,  /* 1..4 seem to be ok */
+		/* no control channel */
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_TONEPORT_UX2] = {
+		.id = "TonePortUX2",
+		.name = "TonePort UX2",
+		.capabilities	= LINE6_CAP_PCM,
+		.altsetting = 2,  /* defaults to 44.1kHz, 16-bit */
+		/* no control channel */
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+};
+
+/*
+	Probe USB device.
+*/
+static int toneport_probe(struct usb_interface *interface,
+			  const struct usb_device_id *id)
+{
+	return line6_probe(interface, id, "Line6-TonePort",
+			   &toneport_properties_table[id->driver_info],
+			   toneport_init, sizeof(struct usb_line6_toneport));
+}
+
+static struct usb_driver toneport_driver = {
+	.name = KBUILD_MODNAME,
+	.probe = toneport_probe,
+	.disconnect = line6_disconnect,
+#ifdef CONFIG_PM
+	.suspend = line6_suspend,
+	.resume = line6_resume,
+	.reset_resume = toneport_reset_resume,
+#endif
+	.id_table = toneport_id_table,
+};
+
+module_usb_driver(toneport_driver);
+
+MODULE_DESCRIPTION("TonePort USB driver");
+MODULE_LICENSE("GPL");
diff --git a/sound/usb/line6/variax.c b/sound/usb/line6/variax.c
new file mode 100644
index 000000000..b2f6637c8
--- /dev/null
+++ b/sound/usb/line6/variax.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Line 6 Linux USB driver
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (line6@grabner-graz.at)
+ */
+
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/usb.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include <sound/core.h>
+
+#include "driver.h"
+
+#define VARIAX_STARTUP_DELAY1 1000
+#define VARIAX_STARTUP_DELAY3 100
+#define VARIAX_STARTUP_DELAY4 100
+
+/*
+	Stages of Variax startup procedure
+*/
+enum {
+	VARIAX_STARTUP_VERSIONREQ,
+	VARIAX_STARTUP_ACTIVATE,
+	VARIAX_STARTUP_SETUP,
+};
+
+enum {
+	LINE6_PODXTLIVE_VARIAX,
+	LINE6_VARIAX
+};
+
+struct usb_line6_variax {
+	/* Generic Line 6 USB data */
+	struct usb_line6 line6;
+
+	/* Buffer for activation code */
+	unsigned char *buffer_activate;
+
+	/* Current progress in startup procedure */
+	int startup_progress;
+};
+
+#define line6_to_variax(x)	container_of(x, struct usb_line6_variax, line6)
+
+#define VARIAX_OFFSET_ACTIVATE 7
+
+/*
+	This message is sent by the device during initialization and identifies
+	the connected guitar version.
+*/
+static const char variax_init_version[] = {
+	0xf0, 0x7e, 0x7f, 0x06, 0x02, 0x00, 0x01, 0x0c,
+	0x07, 0x00, 0x00, 0x00
+};
+
+/*
+	This message is the last one sent by the device during initialization.
+*/
+static const char variax_init_done[] = {
+	0xf0, 0x00, 0x01, 0x0c, 0x07, 0x00, 0x6b
+};
+
+static const char variax_activate[] = {
+	0xf0, 0x00, 0x01, 0x0c, 0x07, 0x00, 0x2a, 0x01,
+	0xf7
+};
+
+static void variax_activate_async(struct usb_line6_variax *variax, int a)
+{
+	variax->buffer_activate[VARIAX_OFFSET_ACTIVATE] = a;
+	line6_send_raw_message_async(&variax->line6, variax->buffer_activate,
+				     sizeof(variax_activate));
+}
+
+/*
+	Variax startup procedure.
+	This is a sequence of functions with special requirements (e.g., must
+	not run immediately after initialization, must not run in interrupt
+	context). After the last one has finished, the device is ready to use.
+*/
+
+static void variax_startup(struct usb_line6 *line6)
+{
+	struct usb_line6_variax *variax = line6_to_variax(line6);
+
+	switch (variax->startup_progress) {
+	case VARIAX_STARTUP_VERSIONREQ:
+		/* repeat request until getting the response */
+		schedule_delayed_work(&line6->startup_work,
+				      msecs_to_jiffies(VARIAX_STARTUP_DELAY1));
+		/* request firmware version: */
+		line6_version_request_async(line6);
+		break;
+	case VARIAX_STARTUP_ACTIVATE:
+		/* activate device: */
+		variax_activate_async(variax, 1);
+		variax->startup_progress = VARIAX_STARTUP_SETUP;
+		schedule_delayed_work(&line6->startup_work,
+				      msecs_to_jiffies(VARIAX_STARTUP_DELAY4));
+		break;
+	case VARIAX_STARTUP_SETUP:
+		/* ALSA audio interface: */
+		snd_card_register(variax->line6.card);
+		break;
+	}
+}
+
+/*
+	Process a completely received message.
+*/
+static void line6_variax_process_message(struct usb_line6 *line6)
+{
+	struct usb_line6_variax *variax = line6_to_variax(line6);
+	const unsigned char *buf = variax->line6.buffer_message;
+
+	switch (buf[0]) {
+	case LINE6_RESET:
+		dev_info(variax->line6.ifcdev, "VARIAX reset\n");
+		break;
+
+	case LINE6_SYSEX_BEGIN:
+		if (memcmp(buf + 1, variax_init_version + 1,
+			   sizeof(variax_init_version) - 1) == 0) {
+			if (variax->startup_progress >= VARIAX_STARTUP_ACTIVATE)
+				break;
+			variax->startup_progress = VARIAX_STARTUP_ACTIVATE;
+			cancel_delayed_work(&line6->startup_work);
+			schedule_delayed_work(&line6->startup_work,
+					      msecs_to_jiffies(VARIAX_STARTUP_DELAY3));
+		} else if (memcmp(buf + 1, variax_init_done + 1,
+				  sizeof(variax_init_done) - 1) == 0) {
+			/* notify of complete initialization: */
+			if (variax->startup_progress >= VARIAX_STARTUP_SETUP)
+				break;
+			cancel_delayed_work(&line6->startup_work);
+			schedule_delayed_work(&line6->startup_work, 0);
+		}
+		break;
+	}
+}
+
+/*
+	Variax destructor.
+*/
+static void line6_variax_disconnect(struct usb_line6 *line6)
+{
+	struct usb_line6_variax *variax = line6_to_variax(line6);
+
+	kfree(variax->buffer_activate);
+}
+
+/*
+	 Try to init workbench device.
+*/
+static int variax_init(struct usb_line6 *line6,
+		       const struct usb_device_id *id)
+{
+	struct usb_line6_variax *variax = line6_to_variax(line6);
+
+	line6->process_message = line6_variax_process_message;
+	line6->disconnect = line6_variax_disconnect;
+	line6->startup = variax_startup;
+
+	/* initialize USB buffers: */
+	variax->buffer_activate = kmemdup(variax_activate,
+					  sizeof(variax_activate), GFP_KERNEL);
+
+	if (variax->buffer_activate == NULL)
+		return -ENOMEM;
+
+	/* initiate startup procedure: */
+	schedule_delayed_work(&line6->startup_work,
+			      msecs_to_jiffies(VARIAX_STARTUP_DELAY1));
+	return 0;
+}
+
+#define LINE6_DEVICE(prod) USB_DEVICE(0x0e41, prod)
+#define LINE6_IF_NUM(prod, n) USB_DEVICE_INTERFACE_NUMBER(0x0e41, prod, n)
+
+/* table of devices that work with this driver */
+static const struct usb_device_id variax_id_table[] = {
+	{ LINE6_IF_NUM(0x4650, 1), .driver_info = LINE6_PODXTLIVE_VARIAX },
+	{ LINE6_DEVICE(0x534d),    .driver_info = LINE6_VARIAX },
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, variax_id_table);
+
+static const struct line6_properties variax_properties_table[] = {
+	[LINE6_PODXTLIVE_VARIAX] = {
+		.id = "PODxtLive",
+		.name = "PODxt Live",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI,
+		.altsetting = 1,
+		.ep_ctrl_r = 0x86,
+		.ep_ctrl_w = 0x05,
+		.ep_audio_r = 0x82,
+		.ep_audio_w = 0x01,
+	},
+	[LINE6_VARIAX] = {
+		.id = "Variax",
+		.name = "Variax Workbench",
+		.capabilities	= LINE6_CAP_CONTROL
+				| LINE6_CAP_CONTROL_MIDI,
+		.altsetting = 1,
+		.ep_ctrl_r = 0x82,
+		.ep_ctrl_w = 0x01,
+		/* no audio channel */
+	}
+};
+
+/*
+	Probe USB device.
+*/
+static int variax_probe(struct usb_interface *interface,
+			const struct usb_device_id *id)
+{
+	return line6_probe(interface, id, "Line6-Variax",
+			   &variax_properties_table[id->driver_info],
+			   variax_init, sizeof(struct usb_line6_variax));
+}
+
+static struct usb_driver variax_driver = {
+	.name = KBUILD_MODNAME,
+	.probe = variax_probe,
+	.disconnect = line6_disconnect,
+#ifdef CONFIG_PM
+	.suspend = line6_suspend,
+	.resume = line6_resume,
+	.reset_resume = line6_resume,
+#endif
+	.id_table = variax_id_table,
+};
+
+module_usb_driver(variax_driver);
+
+MODULE_DESCRIPTION("Variax Workbench USB driver");
+MODULE_LICENSE("GPL");
diff --git a/sound/usb/media.c b/sound/usb/media.c
new file mode 100644
index 000000000..b7497d18e
--- /dev/null
+++ b/sound/usb/media.c
@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * media.c - Media Controller specific ALSA driver code
+ *
+ * Copyright (c) 2019 Shuah Khan <shuah@kernel.org>
+ *
+ */
+
+/*
+ * This file adds Media Controller support to the ALSA driver
+ * to use the Media Controller API to share the tuner with DVB
+ * and V4L2 drivers that control the media device.
+ *
+ * The media device is created based on the existing quirks framework.
+ * Using this approach, the media controller API usage can be added for
+ * a specific device.
+ */
+
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#include <sound/pcm.h>
+#include <sound/core.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "mixer.h"
+#include "media.h"
+
+int snd_media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
+			  int stream)
+{
+	struct media_device *mdev;
+	struct media_ctl *mctl;
+	struct device *pcm_dev = pcm->streams[stream].dev;
+	u32 intf_type;
+	int ret = 0;
+	u16 mixer_pad;
+	struct media_entity *entity;
+
+	mdev = subs->stream->chip->media_dev;
+	if (!mdev)
+		return 0;
+
+	if (subs->media_ctl)
+		return 0;
+
+	/* allocate media_ctl */
+	mctl = kzalloc_obj(*mctl);
+	if (!mctl)
+		return -ENOMEM;
+
+	mctl->media_dev = mdev;
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		intf_type = MEDIA_INTF_T_ALSA_PCM_PLAYBACK;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_PLAYBACK;
+		mctl->media_pad.flags = MEDIA_PAD_FL_SOURCE;
+		mixer_pad = 1;
+	} else {
+		intf_type = MEDIA_INTF_T_ALSA_PCM_CAPTURE;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_CAPTURE;
+		mctl->media_pad.flags = MEDIA_PAD_FL_SINK;
+		mixer_pad = 2;
+	}
+	mctl->media_entity.name = pcm->name;
+	media_entity_pads_init(&mctl->media_entity, 1, &mctl->media_pad);
+	ret =  media_device_register_entity(mctl->media_dev,
+					    &mctl->media_entity);
+	if (ret)
+		goto free_mctl;
+
+	mctl->intf_devnode = media_devnode_create(mdev, intf_type, 0,
+						  MAJOR(pcm_dev->devt),
+						  MINOR(pcm_dev->devt));
+	if (!mctl->intf_devnode) {
+		ret = -ENOMEM;
+		goto unregister_entity;
+	}
+	mctl->intf_link = media_create_intf_link(&mctl->media_entity,
+						 &mctl->intf_devnode->intf,
+						 MEDIA_LNK_FL_ENABLED);
+	if (!mctl->intf_link) {
+		ret = -ENOMEM;
+		goto devnode_remove;
+	}
+
+	/* create link between mixer and audio */
+	media_device_for_each_entity(entity, mdev) {
+		switch (entity->function) {
+		case MEDIA_ENT_F_AUDIO_MIXER:
+			ret = media_create_pad_link(entity, mixer_pad,
+						    &mctl->media_entity, 0,
+						    MEDIA_LNK_FL_ENABLED);
+			if (ret)
+				goto remove_intf_link;
+			break;
+		}
+	}
+
+	subs->media_ctl = mctl;
+	return 0;
+
+remove_intf_link:
+	media_remove_intf_link(mctl->intf_link);
+devnode_remove:
+	media_devnode_remove(mctl->intf_devnode);
+unregister_entity:
+	media_device_unregister_entity(&mctl->media_entity);
+free_mctl:
+	kfree(mctl);
+	return ret;
+}
+
+void snd_media_stream_delete(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = subs->media_ctl;
+
+	if (mctl) {
+		struct media_device *mdev;
+
+		mdev = mctl->media_dev;
+		if (mdev && media_devnode_is_registered(mdev->devnode)) {
+			media_devnode_remove(mctl->intf_devnode);
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+		}
+		kfree(mctl);
+		subs->media_ctl = NULL;
+	}
+}
+
+int snd_media_start_pipeline(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = subs->media_ctl;
+	int ret = 0;
+
+	if (!mctl)
+		return 0;
+
+	guard(mutex)(&mctl->media_dev->graph_mutex);
+	if (mctl->media_dev->enable_source)
+		ret = mctl->media_dev->enable_source(&mctl->media_entity,
+						     &mctl->media_pipe);
+	return ret;
+}
+
+void snd_media_stop_pipeline(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = subs->media_ctl;
+
+	if (!mctl)
+		return;
+
+	guard(mutex)(&mctl->media_dev->graph_mutex);
+	if (mctl->media_dev->disable_source)
+		mctl->media_dev->disable_source(&mctl->media_entity);
+}
+
+static int snd_media_mixer_init(struct snd_usb_audio *chip)
+{
+	struct device *ctl_dev = chip->card->ctl_dev;
+	struct media_intf_devnode *ctl_intf;
+	struct usb_mixer_interface *mixer;
+	struct media_device *mdev = chip->media_dev;
+	struct media_mixer_ctl *mctl;
+	u32 intf_type = MEDIA_INTF_T_ALSA_CONTROL;
+	int ret;
+
+	if (!mdev)
+		return -ENODEV;
+
+	ctl_intf = chip->ctl_intf_media_devnode;
+	if (!ctl_intf) {
+		ctl_intf = media_devnode_create(mdev, intf_type, 0,
+						MAJOR(ctl_dev->devt),
+						MINOR(ctl_dev->devt));
+		if (!ctl_intf)
+			return -ENOMEM;
+		chip->ctl_intf_media_devnode = ctl_intf;
+	}
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+
+		if (mixer->media_mixer_ctl)
+			continue;
+
+		/* allocate media_mixer_ctl */
+		mctl = kzalloc_obj(*mctl);
+		if (!mctl)
+			return -ENOMEM;
+
+		mctl->media_dev = mdev;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_MIXER;
+		mctl->media_entity.name = chip->card->mixername;
+		mctl->media_pad[0].flags = MEDIA_PAD_FL_SINK;
+		mctl->media_pad[1].flags = MEDIA_PAD_FL_SOURCE;
+		mctl->media_pad[2].flags = MEDIA_PAD_FL_SOURCE;
+		media_entity_pads_init(&mctl->media_entity, MEDIA_MIXER_PAD_MAX,
+				  mctl->media_pad);
+		ret =  media_device_register_entity(mctl->media_dev,
+						    &mctl->media_entity);
+		if (ret) {
+			kfree(mctl);
+			return ret;
+		}
+
+		mctl->intf_link = media_create_intf_link(&mctl->media_entity,
+							 &ctl_intf->intf,
+							 MEDIA_LNK_FL_ENABLED);
+		if (!mctl->intf_link) {
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+			kfree(mctl);
+			return -ENOMEM;
+		}
+		mctl->intf_devnode = ctl_intf;
+		mixer->media_mixer_ctl = mctl;
+	}
+	return 0;
+}
+
+static void snd_media_mixer_delete(struct snd_usb_audio *chip)
+{
+	struct usb_mixer_interface *mixer;
+	struct media_device *mdev = chip->media_dev;
+
+	if (!mdev)
+		return;
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		struct media_mixer_ctl *mctl;
+
+		mctl = mixer->media_mixer_ctl;
+		if (!mixer->media_mixer_ctl)
+			continue;
+
+		if (media_devnode_is_registered(mdev->devnode)) {
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+		}
+		kfree(mctl);
+		mixer->media_mixer_ctl = NULL;
+	}
+	if (media_devnode_is_registered(mdev->devnode))
+		media_devnode_remove(chip->ctl_intf_media_devnode);
+	chip->ctl_intf_media_devnode = NULL;
+}
+
+int snd_media_device_create(struct snd_usb_audio *chip,
+			struct usb_interface *iface)
+{
+	struct media_device *mdev;
+	struct usb_device *usbdev = interface_to_usbdev(iface);
+	int ret = 0;
+
+	/* usb-audio driver is probed for each usb interface, and
+	 * there are multiple interfaces per device. Avoid calling
+	 * media_device_usb_allocate() each time usb_audio_probe()
+	 * is called. Do it only once.
+	 */
+	if (chip->media_dev) {
+		mdev = chip->media_dev;
+		goto snd_mixer_init;
+	}
+
+	mdev = media_device_usb_allocate(usbdev, KBUILD_MODNAME, THIS_MODULE);
+	if (IS_ERR(mdev))
+		return -ENOMEM;
+
+	/* save media device - avoid lookups */
+	chip->media_dev = mdev;
+
+snd_mixer_init:
+	/* Create media entities for mixer and control dev */
+	ret = snd_media_mixer_init(chip);
+	/* media_device might be registered, print error and continue */
+	if (ret)
+		dev_err(&usbdev->dev,
+			"Couldn't create media mixer entities. Error: %d\n",
+			ret);
+
+	if (!media_devnode_is_registered(mdev->devnode)) {
+		/* don't register if snd_media_mixer_init() failed */
+		if (ret)
+			goto create_fail;
+
+		/* register media_device */
+		ret = media_device_register(mdev);
+create_fail:
+		if (ret) {
+			snd_media_mixer_delete(chip);
+			media_device_delete(mdev, KBUILD_MODNAME, THIS_MODULE);
+			/* clear saved media_dev */
+			chip->media_dev = NULL;
+			dev_err(&usbdev->dev,
+				"Couldn't register media device. Error: %d\n",
+				ret);
+			return ret;
+		}
+	}
+
+	return ret;
+}
+
+void snd_media_device_delete(struct snd_usb_audio *chip)
+{
+	struct media_device *mdev = chip->media_dev;
+	struct snd_usb_stream *stream;
+
+	/* release resources */
+	list_for_each_entry(stream, &chip->pcm_list, list) {
+		snd_media_stream_delete(&stream->substream[0]);
+		snd_media_stream_delete(&stream->substream[1]);
+	}
+
+	snd_media_mixer_delete(chip);
+
+	if (mdev) {
+		media_device_delete(mdev, KBUILD_MODNAME, THIS_MODULE);
+		chip->media_dev = NULL;
+	}
+}
diff --git a/sound/usb/media.h b/sound/usb/media.h
new file mode 100644
index 000000000..f5bdec1d6
--- /dev/null
+++ b/sound/usb/media.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * media.h - Media Controller specific ALSA driver code
+ *
+ * Copyright (c) 2019 Shuah Khan <shuah@kernel.org>
+ *
+ */
+
+/*
+ * This file adds Media Controller support to the ALSA driver
+ * to use the Media Controller API to share the tuner with DVB
+ * and V4L2 drivers that control the media device.
+ *
+ * The media device is created based on the existing quirks framework.
+ * Using this approach, the media controller API usage can be added for
+ * a specific device.
+ */
+#ifndef __MEDIA_H
+
+#ifdef CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER
+
+#include <linux/media.h>
+#include <media/media-device.h>
+#include <media/media-entity.h>
+#include <media/media-dev-allocator.h>
+#include <sound/asound.h>
+
+struct media_ctl {
+	struct media_device *media_dev;
+	struct media_entity media_entity;
+	struct media_intf_devnode *intf_devnode;
+	struct media_link *intf_link;
+	struct media_pad media_pad;
+	struct media_pipeline media_pipe;
+};
+
+/*
+ * One source pad each for SNDRV_PCM_STREAM_CAPTURE and
+ * SNDRV_PCM_STREAM_PLAYBACK. One for sink pad to link
+ * to AUDIO Source
+ */
+#define MEDIA_MIXER_PAD_MAX    (SNDRV_PCM_STREAM_LAST + 2)
+
+struct media_mixer_ctl {
+	struct media_device *media_dev;
+	struct media_entity media_entity;
+	struct media_intf_devnode *intf_devnode;
+	struct media_link *intf_link;
+	struct media_pad media_pad[MEDIA_MIXER_PAD_MAX];
+	struct media_pipeline media_pipe;
+};
+
+int snd_media_device_create(struct snd_usb_audio *chip,
+			    struct usb_interface *iface);
+void snd_media_device_delete(struct snd_usb_audio *chip);
+int snd_media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
+			  int stream);
+void snd_media_stream_delete(struct snd_usb_substream *subs);
+int snd_media_start_pipeline(struct snd_usb_substream *subs);
+void snd_media_stop_pipeline(struct snd_usb_substream *subs);
+#else
+static inline int snd_media_device_create(struct snd_usb_audio *chip,
+					  struct usb_interface *iface)
+						{ return 0; }
+static inline void snd_media_device_delete(struct snd_usb_audio *chip) { }
+static inline int snd_media_stream_init(struct snd_usb_substream *subs,
+					struct snd_pcm *pcm, int stream)
+						{ return 0; }
+static inline void snd_media_stream_delete(struct snd_usb_substream *subs) { }
+static inline int snd_media_start_pipeline(struct snd_usb_substream *subs)
+					{ return 0; }
+static inline void snd_media_stop_pipeline(struct snd_usb_substream *subs) { }
+#endif
+#endif /* __MEDIA_H */
diff --git a/sound/usb/midi.c b/sound/usb/midi.c
new file mode 100644
index 000000000..7e5b1b133
--- /dev/null
+++ b/sound/usb/midi.c
@@ -0,0 +1,2659 @@
+/*
+ * usbmidi.c - ALSA USB MIDI driver
+ *
+ * Copyright (c) 2002-2009 Clemens Ladisch
+ * All rights reserved.
+ *
+ * Based on the OSS usb-midi driver by NAGANO Daisuke,
+ *          NetBSD's umidi driver by Takuya SHIOZAKI,
+ *          the "USB Device Class Definition for MIDI Devices" by Roland
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed and/or modified under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 2 of the License, or (at your option) any later
+ * version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+#include <linux/usb.h>
+#include <linux/wait.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/midi.h>
+#include <linux/module.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/rawmidi.h>
+#include <sound/asequencer.h>
+#include "usbaudio.h"
+#include "midi.h"
+#include "power.h"
+#include "helper.h"
+
+/*
+ * define this to log all USB packets
+ */
+/* #define DUMP_PACKETS */
+
+/*
+ * how long to wait after some USB errors, so that hub_wq can disconnect() us
+ * without too many spurious errors
+ */
+#define ERROR_DELAY_JIFFIES (HZ / 10)
+
+#define OUTPUT_URBS 7
+#define INPUT_URBS 7
+
+
+MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
+MODULE_DESCRIPTION("USB Audio/MIDI helper module");
+MODULE_LICENSE("Dual BSD/GPL");
+
+struct snd_usb_midi_in_endpoint;
+struct snd_usb_midi_out_endpoint;
+struct snd_usb_midi_endpoint;
+
+struct usb_protocol_ops {
+	void (*input)(struct snd_usb_midi_in_endpoint*, uint8_t*, int);
+	void (*output)(struct snd_usb_midi_out_endpoint *ep, struct urb *urb);
+	void (*output_packet)(struct urb*, uint8_t, uint8_t, uint8_t, uint8_t);
+	void (*init_out_endpoint)(struct snd_usb_midi_out_endpoint *);
+	void (*finish_out_endpoint)(struct snd_usb_midi_out_endpoint *);
+};
+
+struct snd_usb_midi {
+	struct usb_device *dev;
+	struct snd_card *card;
+	struct usb_interface *iface;
+	const struct snd_usb_audio_quirk *quirk;
+	struct snd_rawmidi *rmidi;
+	const struct usb_protocol_ops *usb_protocol_ops;
+	struct list_head list;
+	struct timer_list error_timer;
+	spinlock_t disc_lock;
+	struct rw_semaphore disc_rwsem;
+	struct mutex mutex;
+	u32 usb_id;
+	int next_midi_device;
+
+	struct snd_usb_midi_endpoint {
+		struct snd_usb_midi_out_endpoint *out;
+		struct snd_usb_midi_in_endpoint *in;
+	} endpoints[MIDI_MAX_ENDPOINTS];
+	unsigned long input_triggered;
+	unsigned int opened[2];
+	unsigned char disconnected;
+	unsigned char input_running;
+
+	struct snd_kcontrol *roland_load_ctl;
+};
+
+struct snd_usb_midi_out_endpoint {
+	struct snd_usb_midi *umidi;
+	struct out_urb_context {
+		struct urb *urb;
+		struct snd_usb_midi_out_endpoint *ep;
+	} urbs[OUTPUT_URBS];
+	unsigned int active_urbs;
+	unsigned int drain_urbs;
+	int max_transfer;		/* size of urb buffer */
+	struct work_struct work;
+	unsigned int next_urb;
+	spinlock_t buffer_lock;
+
+	struct usbmidi_out_port {
+		struct snd_usb_midi_out_endpoint *ep;
+		struct snd_rawmidi_substream *substream;
+		int active;
+		uint8_t cable;		/* cable number << 4 */
+		uint8_t state;
+#define STATE_UNKNOWN	0
+#define STATE_1PARAM	1
+#define STATE_2PARAM_1	2
+#define STATE_2PARAM_2	3
+#define STATE_SYSEX_0	4
+#define STATE_SYSEX_1	5
+#define STATE_SYSEX_2	6
+		uint8_t data[2];
+	} ports[0x10];
+	int current_port;
+
+	wait_queue_head_t drain_wait;
+};
+
+struct snd_usb_midi_in_endpoint {
+	struct snd_usb_midi *umidi;
+	struct urb *urbs[INPUT_URBS];
+	struct usbmidi_in_port {
+		struct snd_rawmidi_substream *substream;
+		u8 running_status_length;
+	} ports[0x10];
+	u8 seen_f5;
+	bool in_sysex;
+	u8 last_cin;
+	u8 error_resubmit;
+	int current_port;
+};
+
+static void snd_usbmidi_do_output(struct snd_usb_midi_out_endpoint *ep);
+
+static const uint8_t snd_usbmidi_cin_length[] = {
+	0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
+};
+
+/*
+ * Submits the URB, with error handling.
+ */
+static int snd_usbmidi_submit_urb(struct urb *urb, gfp_t flags)
+{
+	int err = usb_submit_urb(urb, flags);
+	if (err < 0 && err != -ENODEV)
+		dev_err(&urb->dev->dev, "usb_submit_urb: %d\n", err);
+	return err;
+}
+
+/*
+ * Error handling for URB completion functions.
+ */
+static int snd_usbmidi_urb_error(const struct urb *urb)
+{
+	switch (urb->status) {
+	/* manually unlinked, or device gone */
+	case -ENOENT:
+	case -ECONNRESET:
+	case -ESHUTDOWN:
+	case -ENODEV:
+		return -ENODEV;
+	/* errors that might occur during unplugging */
+	case -EPROTO:
+	case -ETIME:
+	case -EILSEQ:
+		return -EIO;
+	default:
+		dev_err(&urb->dev->dev, "urb status %d\n", urb->status);
+		return 0; /* continue */
+	}
+}
+
+/*
+ * Receives a chunk of MIDI data.
+ */
+static void snd_usbmidi_input_data(struct snd_usb_midi_in_endpoint *ep,
+				   int portidx, uint8_t *data, int length)
+{
+	struct usbmidi_in_port *port = &ep->ports[portidx];
+
+	if (!port->substream) {
+		dev_dbg(&ep->umidi->dev->dev, "unexpected port %d!\n", portidx);
+		return;
+	}
+	if (!test_bit(port->substream->number, &ep->umidi->input_triggered))
+		return;
+	snd_rawmidi_receive(port->substream, data, length);
+}
+
+#ifdef DUMP_PACKETS
+static void dump_urb(const char *type, const u8 *data, int length)
+{
+	pr_debug("%s packet: [", type);
+	for (; length > 0; ++data, --length)
+		pr_cont(" %02x", *data);
+	pr_cont(" ]\n");
+}
+#else
+#define dump_urb(type, data, length) /* nothing */
+#endif
+
+/*
+ * Processes the data read from the device.
+ */
+static void snd_usbmidi_in_urb_complete(struct urb *urb)
+{
+	struct snd_usb_midi_in_endpoint *ep = urb->context;
+
+	if (urb->status == 0) {
+		dump_urb("received", urb->transfer_buffer, urb->actual_length);
+		ep->umidi->usb_protocol_ops->input(ep, urb->transfer_buffer,
+						   urb->actual_length);
+	} else {
+		int err = snd_usbmidi_urb_error(urb);
+		if (err < 0) {
+			if (err != -ENODEV) {
+				ep->error_resubmit = 1;
+				mod_timer(&ep->umidi->error_timer,
+					  jiffies + ERROR_DELAY_JIFFIES);
+			}
+			return;
+		}
+	}
+
+	urb->dev = ep->umidi->dev;
+	snd_usbmidi_submit_urb(urb, GFP_ATOMIC);
+}
+
+static void snd_usbmidi_out_urb_complete(struct urb *urb)
+{
+	struct out_urb_context *context = urb->context;
+	struct snd_usb_midi_out_endpoint *ep = context->ep;
+	unsigned int urb_index;
+
+	scoped_guard(spinlock_irqsave, &ep->buffer_lock) {
+		urb_index = context - ep->urbs;
+		ep->active_urbs &= ~(1 << urb_index);
+		if (unlikely(ep->drain_urbs)) {
+			ep->drain_urbs &= ~(1 << urb_index);
+			wake_up(&ep->drain_wait);
+		}
+	}
+	if (urb->status < 0) {
+		int err = snd_usbmidi_urb_error(urb);
+		if (err < 0) {
+			if (err != -ENODEV)
+				mod_timer(&ep->umidi->error_timer,
+					  jiffies + ERROR_DELAY_JIFFIES);
+			return;
+		}
+	}
+	snd_usbmidi_do_output(ep);
+}
+
+/*
+ * This is called when some data should be transferred to the device
+ * (from one or more substreams).
+ */
+static void snd_usbmidi_do_output(struct snd_usb_midi_out_endpoint *ep)
+{
+	unsigned int urb_index;
+	struct urb *urb;
+
+	guard(spinlock_irqsave)(&ep->buffer_lock);
+	if (ep->umidi->disconnected)
+		return;
+
+	urb_index = ep->next_urb;
+	for (;;) {
+		if (!(ep->active_urbs & (1 << urb_index))) {
+			urb = ep->urbs[urb_index].urb;
+			urb->transfer_buffer_length = 0;
+			ep->umidi->usb_protocol_ops->output(ep, urb);
+			if (urb->transfer_buffer_length == 0)
+				break;
+
+			dump_urb("sending", urb->transfer_buffer,
+				 urb->transfer_buffer_length);
+			urb->dev = ep->umidi->dev;
+			if (snd_usbmidi_submit_urb(urb, GFP_ATOMIC) < 0)
+				break;
+			ep->active_urbs |= 1 << urb_index;
+		}
+		if (++urb_index >= OUTPUT_URBS)
+			urb_index = 0;
+		if (urb_index == ep->next_urb)
+			break;
+	}
+	ep->next_urb = urb_index;
+}
+
+static void snd_usbmidi_out_work(struct work_struct *work)
+{
+	struct snd_usb_midi_out_endpoint *ep =
+		container_of(work, struct snd_usb_midi_out_endpoint, work);
+
+	snd_usbmidi_do_output(ep);
+}
+
+/* called after transfers had been interrupted due to some USB error */
+static void snd_usbmidi_error_timer(struct timer_list *t)
+{
+	struct snd_usb_midi *umidi = timer_container_of(umidi, t, error_timer);
+	unsigned int i, j;
+
+	guard(spinlock)(&umidi->disc_lock);
+	if (umidi->disconnected) {
+		return;
+	}
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
+		struct snd_usb_midi_in_endpoint *in = umidi->endpoints[i].in;
+		if (in && in->error_resubmit) {
+			in->error_resubmit = 0;
+			for (j = 0; j < INPUT_URBS; ++j) {
+				if (atomic_read(&in->urbs[j]->use_count))
+					continue;
+				in->urbs[j]->dev = umidi->dev;
+				snd_usbmidi_submit_urb(in->urbs[j], GFP_ATOMIC);
+			}
+		}
+		if (umidi->endpoints[i].out)
+			snd_usbmidi_do_output(umidi->endpoints[i].out);
+	}
+}
+
+/* helper function to send static data that may not DMA-able */
+static int send_bulk_static_data(struct snd_usb_midi_out_endpoint *ep,
+				 const void *data, int len)
+{
+	int err = 0;
+	void *buf = kmemdup(data, len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	dump_urb("sending", buf, len);
+	if (ep->urbs[0].urb)
+		err = usb_bulk_msg(ep->umidi->dev, ep->urbs[0].urb->pipe,
+				   buf, len, NULL, 250);
+	kfree(buf);
+	return err;
+}
+
+/*
+ * Standard USB MIDI protocol: see the spec.
+ * Midiman protocol: like the standard protocol, but the control byte is the
+ * fourth byte in each packet, and uses length instead of CIN.
+ */
+
+static void snd_usbmidi_standard_input(struct snd_usb_midi_in_endpoint *ep,
+				       uint8_t *buffer, int buffer_length)
+{
+	int i;
+
+	for (i = 0; i + 3 < buffer_length; i += 4)
+		if (buffer[i] != 0) {
+			int cable = buffer[i] >> 4;
+			int length = snd_usbmidi_cin_length[buffer[i] & 0x0f];
+			snd_usbmidi_input_data(ep, cable, &buffer[i + 1],
+					       length);
+		}
+}
+
+static void snd_usbmidi_midiman_input(struct snd_usb_midi_in_endpoint *ep,
+				      uint8_t *buffer, int buffer_length)
+{
+	int i;
+
+	for (i = 0; i + 3 < buffer_length; i += 4)
+		if (buffer[i + 3] != 0) {
+			int port = buffer[i + 3] >> 4;
+			int length = buffer[i + 3] & 3;
+			snd_usbmidi_input_data(ep, port, &buffer[i], length);
+		}
+}
+
+/*
+ * Buggy M-Audio device: running status on input results in a packet that has
+ * the data bytes but not the status byte and that is marked with CIN 4.
+ */
+static void snd_usbmidi_maudio_broken_running_status_input(
+					struct snd_usb_midi_in_endpoint *ep,
+					uint8_t *buffer, int buffer_length)
+{
+	int i;
+
+	for (i = 0; i + 3 < buffer_length; i += 4)
+		if (buffer[i] != 0) {
+			int cable = buffer[i] >> 4;
+			u8 cin = buffer[i] & 0x0f;
+			struct usbmidi_in_port *port = &ep->ports[cable];
+			int length;
+
+			length = snd_usbmidi_cin_length[cin];
+			if (cin == 0xf && buffer[i + 1] >= 0xf8)
+				; /* realtime msg: no running status change */
+			else if (cin >= 0x8 && cin <= 0xe)
+				/* channel msg */
+				port->running_status_length = length - 1;
+			else if (cin == 0x4 &&
+				 port->running_status_length != 0 &&
+				 buffer[i + 1] < 0x80)
+				/* CIN 4 that is not a SysEx */
+				length = port->running_status_length;
+			else
+				/*
+				 * All other msgs cannot begin running status.
+				 * (A channel msg sent as two or three CIN 0xF
+				 * packets could in theory, but this device
+				 * doesn't use this format.)
+				 */
+				port->running_status_length = 0;
+			snd_usbmidi_input_data(ep, cable, &buffer[i + 1],
+					       length);
+		}
+}
+
+/*
+ * QinHeng CH345 is buggy: every second packet inside a SysEx has not CIN 4
+ * but the previously seen CIN, but still with three data bytes.
+ */
+static void ch345_broken_sysex_input(struct snd_usb_midi_in_endpoint *ep,
+				     uint8_t *buffer, int buffer_length)
+{
+	unsigned int i, cin, length;
+
+	for (i = 0; i + 3 < buffer_length; i += 4) {
+		if (buffer[i] == 0 && i > 0)
+			break;
+		cin = buffer[i] & 0x0f;
+		if (ep->in_sysex &&
+		    cin == ep->last_cin &&
+		    (buffer[i + 1 + (cin == 0x6)] & 0x80) == 0)
+			cin = 0x4;
+#if 0
+		if (buffer[i + 1] == 0x90) {
+			/*
+			 * Either a corrupted running status or a real note-on
+			 * message; impossible to detect reliably.
+			 */
+		}
+#endif
+		length = snd_usbmidi_cin_length[cin];
+		snd_usbmidi_input_data(ep, 0, &buffer[i + 1], length);
+		ep->in_sysex = cin == 0x4;
+		if (!ep->in_sysex)
+			ep->last_cin = cin;
+	}
+}
+
+/*
+ * CME protocol: like the standard protocol, but SysEx commands are sent as a
+ * single USB packet preceded by a 0x0F byte, as are system realtime
+ * messages and MIDI Active Sensing.
+ * Also, multiple messages can be sent in the same packet.
+ */
+static void snd_usbmidi_cme_input(struct snd_usb_midi_in_endpoint *ep,
+				  uint8_t *buffer, int buffer_length)
+{
+	int remaining = buffer_length;
+
+	/*
+	 * CME send sysex, song position pointer, system realtime
+	 * and active sensing using CIN 0x0f, which in the standard
+	 * is only intended for single byte unparsed data.
+	 * So we need to interpret these here before sending them on.
+	 * By default, we assume single byte data, which is true
+	 * for system realtime (midi clock, start, stop and continue)
+	 * and active sensing, and handle the other (known) cases
+	 * separately.
+	 * In contrast to the standard, CME does not split sysex
+	 * into multiple 4-byte packets, but lumps everything together
+	 * into one. In addition, CME can string multiple messages
+	 * together in the same packet; pressing the Record button
+	 * on an UF6 sends a sysex message directly followed
+	 * by a song position pointer in the same packet.
+	 * For it to have any reasonable meaning, a sysex message
+	 * needs to be at least 3 bytes in length (0xf0, id, 0xf7),
+	 * corresponding to a packet size of 4 bytes, and the ones sent
+	 * by CME devices are 6 or 7 bytes, making the packet fragments
+	 * 7 or 8 bytes long (six or seven bytes plus preceding CN+CIN byte).
+	 * For the other types, the packet size is always 4 bytes,
+	 * as per the standard, with the data size being 3 for SPP
+	 * and 1 for the others.
+	 * Thus all packet fragments are at least 4 bytes long, so we can
+	 * skip anything that is shorter; this also conveniantly skips
+	 * packets with size 0, which CME devices continuously send when
+	 * they have nothing better to do.
+	 * Another quirk is that sometimes multiple messages are sent
+	 * in the same packet. This has been observed for midi clock
+	 * and active sensing i.e. 0x0f 0xf8 0x00 0x00 0x0f 0xfe 0x00 0x00,
+	 * but also multiple note ons/offs, and control change together
+	 * with MIDI clock. Similarly, some sysex messages are followed by
+	 * the song position pointer in the same packet, and occasionally
+	 * additionally by a midi clock or active sensing.
+	 * We handle this by looping over all data and parsing it along the way.
+	 */
+	while (remaining >= 4) {
+		int source_length = 4; /* default */
+
+		if ((buffer[0] & 0x0f) == 0x0f) {
+			int data_length = 1; /* default */
+
+			if (buffer[1] == 0xf0) {
+				/* Sysex: Find EOX and send on whole message. */
+				/* To kick off the search, skip the first
+				 * two bytes (CN+CIN and SYSEX (0xf0).
+				 */
+				uint8_t *tmp_buf = buffer + 2;
+				int tmp_length = remaining - 2;
+
+				while (tmp_length > 1 && *tmp_buf != 0xf7) {
+					tmp_buf++;
+					tmp_length--;
+				}
+				data_length = tmp_buf - buffer;
+				source_length = data_length + 1;
+			} else if (buffer[1] == 0xf2) {
+				/* Three byte song position pointer */
+				data_length = 3;
+			}
+			snd_usbmidi_input_data(ep, buffer[0] >> 4,
+					       &buffer[1], data_length);
+		} else {
+			/* normal channel events */
+			snd_usbmidi_standard_input(ep, buffer, source_length);
+		}
+		buffer += source_length;
+		remaining -= source_length;
+	}
+}
+
+/*
+ * Adds one USB MIDI packet to the output buffer.
+ */
+static void snd_usbmidi_output_standard_packet(struct urb *urb, uint8_t p0,
+					       uint8_t p1, uint8_t p2,
+					       uint8_t p3)
+{
+
+	uint8_t *buf =
+		(uint8_t *)urb->transfer_buffer + urb->transfer_buffer_length;
+	buf[0] = p0;
+	buf[1] = p1;
+	buf[2] = p2;
+	buf[3] = p3;
+	urb->transfer_buffer_length += 4;
+}
+
+/*
+ * Adds one Midiman packet to the output buffer.
+ */
+static void snd_usbmidi_output_midiman_packet(struct urb *urb, uint8_t p0,
+					      uint8_t p1, uint8_t p2,
+					      uint8_t p3)
+{
+
+	uint8_t *buf =
+		(uint8_t *)urb->transfer_buffer + urb->transfer_buffer_length;
+	buf[0] = p1;
+	buf[1] = p2;
+	buf[2] = p3;
+	buf[3] = (p0 & 0xf0) | snd_usbmidi_cin_length[p0 & 0x0f];
+	urb->transfer_buffer_length += 4;
+}
+
+/*
+ * Converts MIDI commands to USB MIDI packets.
+ */
+static void snd_usbmidi_transmit_byte(struct usbmidi_out_port *port,
+				      uint8_t b, struct urb *urb)
+{
+	uint8_t p0 = port->cable;
+	void (*output_packet)(struct urb*, uint8_t, uint8_t, uint8_t, uint8_t) =
+		port->ep->umidi->usb_protocol_ops->output_packet;
+
+	if (b >= 0xf8) {
+		output_packet(urb, p0 | 0x0f, b, 0, 0);
+	} else if (b >= 0xf0) {
+		switch (b) {
+		case 0xf0:
+			port->data[0] = b;
+			port->state = STATE_SYSEX_1;
+			break;
+		case 0xf1:
+		case 0xf3:
+			port->data[0] = b;
+			port->state = STATE_1PARAM;
+			break;
+		case 0xf2:
+			port->data[0] = b;
+			port->state = STATE_2PARAM_1;
+			break;
+		case 0xf4:
+		case 0xf5:
+			port->state = STATE_UNKNOWN;
+			break;
+		case 0xf6:
+			output_packet(urb, p0 | 0x05, 0xf6, 0, 0);
+			port->state = STATE_UNKNOWN;
+			break;
+		case 0xf7:
+			switch (port->state) {
+			case STATE_SYSEX_0:
+				output_packet(urb, p0 | 0x05, 0xf7, 0, 0);
+				break;
+			case STATE_SYSEX_1:
+				output_packet(urb, p0 | 0x06, port->data[0],
+					      0xf7, 0);
+				break;
+			case STATE_SYSEX_2:
+				output_packet(urb, p0 | 0x07, port->data[0],
+					      port->data[1], 0xf7);
+				break;
+			}
+			port->state = STATE_UNKNOWN;
+			break;
+		}
+	} else if (b >= 0x80) {
+		port->data[0] = b;
+		if (b >= 0xc0 && b <= 0xdf)
+			port->state = STATE_1PARAM;
+		else
+			port->state = STATE_2PARAM_1;
+	} else { /* b < 0x80 */
+		switch (port->state) {
+		case STATE_1PARAM:
+			if (port->data[0] < 0xf0) {
+				p0 |= port->data[0] >> 4;
+			} else {
+				p0 |= 0x02;
+				port->state = STATE_UNKNOWN;
+			}
+			output_packet(urb, p0, port->data[0], b, 0);
+			break;
+		case STATE_2PARAM_1:
+			port->data[1] = b;
+			port->state = STATE_2PARAM_2;
+			break;
+		case STATE_2PARAM_2:
+			if (port->data[0] < 0xf0) {
+				p0 |= port->data[0] >> 4;
+				port->state = STATE_2PARAM_1;
+			} else {
+				p0 |= 0x03;
+				port->state = STATE_UNKNOWN;
+			}
+			output_packet(urb, p0, port->data[0], port->data[1], b);
+			break;
+		case STATE_SYSEX_0:
+			port->data[0] = b;
+			port->state = STATE_SYSEX_1;
+			break;
+		case STATE_SYSEX_1:
+			port->data[1] = b;
+			port->state = STATE_SYSEX_2;
+			break;
+		case STATE_SYSEX_2:
+			output_packet(urb, p0 | 0x04, port->data[0],
+				      port->data[1], b);
+			port->state = STATE_SYSEX_0;
+			break;
+		}
+	}
+}
+
+static void snd_usbmidi_standard_output(struct snd_usb_midi_out_endpoint *ep,
+					struct urb *urb)
+{
+	int port0 = ep->current_port;
+	int i;
+
+	for (i = 0; i < 0x10; ++i) {
+		int portnum = (port0 + i) & 15;
+		struct usbmidi_out_port *port = &ep->ports[portnum];
+
+		if (!port->active)
+			continue;
+		while (urb->transfer_buffer_length + 3 < ep->max_transfer) {
+			uint8_t b;
+
+			if (snd_rawmidi_transmit(port->substream, &b, 1) != 1) {
+				port->active = 0;
+				break;
+			}
+			snd_usbmidi_transmit_byte(port, b, urb);
+		}
+	}
+	ep->current_port = (port0 + 1) & 15;
+}
+
+static const struct usb_protocol_ops snd_usbmidi_standard_ops = {
+	.input = snd_usbmidi_standard_input,
+	.output = snd_usbmidi_standard_output,
+	.output_packet = snd_usbmidi_output_standard_packet,
+};
+
+static const struct usb_protocol_ops snd_usbmidi_midiman_ops = {
+	.input = snd_usbmidi_midiman_input,
+	.output = snd_usbmidi_standard_output,
+	.output_packet = snd_usbmidi_output_midiman_packet,
+};
+
+static const
+struct usb_protocol_ops snd_usbmidi_maudio_broken_running_status_ops = {
+	.input = snd_usbmidi_maudio_broken_running_status_input,
+	.output = snd_usbmidi_standard_output,
+	.output_packet = snd_usbmidi_output_standard_packet,
+};
+
+static const struct usb_protocol_ops snd_usbmidi_cme_ops = {
+	.input = snd_usbmidi_cme_input,
+	.output = snd_usbmidi_standard_output,
+	.output_packet = snd_usbmidi_output_standard_packet,
+};
+
+static const struct usb_protocol_ops snd_usbmidi_ch345_broken_sysex_ops = {
+	.input = ch345_broken_sysex_input,
+	.output = snd_usbmidi_standard_output,
+	.output_packet = snd_usbmidi_output_standard_packet,
+};
+
+/*
+ * AKAI MPD16 protocol:
+ *
+ * For control port (endpoint 1):
+ * ==============================
+ * One or more chunks consisting of first byte of (0x10 | msg_len) and then a
+ * SysEx message (msg_len=9 bytes long).
+ *
+ * For data port (endpoint 2):
+ * ===========================
+ * One or more chunks consisting of first byte of (0x20 | msg_len) and then a
+ * MIDI message (msg_len bytes long)
+ *
+ * Messages sent: Active Sense, Note On, Poly Pressure, Control Change.
+ */
+static void snd_usbmidi_akai_input(struct snd_usb_midi_in_endpoint *ep,
+				   uint8_t *buffer, int buffer_length)
+{
+	unsigned int pos = 0;
+	unsigned int len = (unsigned int)buffer_length;
+	while (pos < len) {
+		unsigned int port = (buffer[pos] >> 4) - 1;
+		unsigned int msg_len = buffer[pos] & 0x0f;
+		pos++;
+		if (pos + msg_len <= len && port < 2)
+			snd_usbmidi_input_data(ep, 0, &buffer[pos], msg_len);
+		pos += msg_len;
+	}
+}
+
+#define MAX_AKAI_SYSEX_LEN 9
+
+static void snd_usbmidi_akai_output(struct snd_usb_midi_out_endpoint *ep,
+				    struct urb *urb)
+{
+	uint8_t *msg;
+	int pos, end, count, buf_end;
+	uint8_t tmp[MAX_AKAI_SYSEX_LEN];
+	struct snd_rawmidi_substream *substream = ep->ports[0].substream;
+
+	if (!ep->ports[0].active)
+		return;
+
+	msg = urb->transfer_buffer + urb->transfer_buffer_length;
+	buf_end = ep->max_transfer - MAX_AKAI_SYSEX_LEN - 1;
+	if (buf_end <= 0)
+		return;
+
+	/* only try adding more data when there's space for at least 1 SysEx */
+	while (urb->transfer_buffer_length < buf_end) {
+		count = snd_rawmidi_transmit_peek(substream,
+						  tmp, MAX_AKAI_SYSEX_LEN);
+		if (!count) {
+			ep->ports[0].active = 0;
+			return;
+		}
+		/* try to skip non-SysEx data */
+		for (pos = 0; pos < count && tmp[pos] != 0xF0; pos++)
+			;
+
+		if (pos > 0) {
+			snd_rawmidi_transmit_ack(substream, pos);
+			continue;
+		}
+
+		/* look for the start or end marker */
+		for (end = 1; end < count && tmp[end] < 0xF0; end++)
+			;
+
+		/* next SysEx started before the end of current one */
+		if (end < count && tmp[end] == 0xF0) {
+			/* it's incomplete - drop it */
+			snd_rawmidi_transmit_ack(substream, end);
+			continue;
+		}
+		/* SysEx complete */
+		if (end < count && tmp[end] == 0xF7) {
+			/* queue it, ack it, and get the next one */
+			count = end + 1;
+			msg[0] = 0x10 | count;
+			memcpy(&msg[1], tmp, count);
+			snd_rawmidi_transmit_ack(substream, count);
+			urb->transfer_buffer_length += count + 1;
+			msg += count + 1;
+			continue;
+		}
+		/* less than 9 bytes and no end byte - wait for more */
+		if (count < MAX_AKAI_SYSEX_LEN) {
+			ep->ports[0].active = 0;
+			return;
+		}
+		/* 9 bytes and no end marker in sight - malformed, skip it */
+		snd_rawmidi_transmit_ack(substream, count);
+	}
+}
+
+static const struct usb_protocol_ops snd_usbmidi_akai_ops = {
+	.input = snd_usbmidi_akai_input,
+	.output = snd_usbmidi_akai_output,
+};
+
+/*
+ * Novation USB MIDI protocol: number of data bytes is in the first byte
+ * (when receiving) (+1!) or in the second byte (when sending); data begins
+ * at the third byte.
+ */
+
+static void snd_usbmidi_novation_input(struct snd_usb_midi_in_endpoint *ep,
+				       uint8_t *buffer, int buffer_length)
+{
+	if (buffer_length < 2 || !buffer[0] || buffer_length < buffer[0] + 1)
+		return;
+	snd_usbmidi_input_data(ep, 0, &buffer[2], buffer[0] - 1);
+}
+
+static void snd_usbmidi_novation_output(struct snd_usb_midi_out_endpoint *ep,
+					struct urb *urb)
+{
+	uint8_t *transfer_buffer;
+	int count;
+
+	if (!ep->ports[0].active)
+		return;
+	if (ep->max_transfer < 3)
+		return;
+	transfer_buffer = urb->transfer_buffer;
+	count = snd_rawmidi_transmit(ep->ports[0].substream,
+				     &transfer_buffer[2],
+				     ep->max_transfer - 2);
+	if (count < 1) {
+		ep->ports[0].active = 0;
+		return;
+	}
+	transfer_buffer[0] = 0;
+	transfer_buffer[1] = count;
+	urb->transfer_buffer_length = 2 + count;
+}
+
+static const struct usb_protocol_ops snd_usbmidi_novation_ops = {
+	.input = snd_usbmidi_novation_input,
+	.output = snd_usbmidi_novation_output,
+};
+
+/*
+ * "raw" protocol: just move raw MIDI bytes from/to the endpoint
+ */
+
+static void snd_usbmidi_raw_input(struct snd_usb_midi_in_endpoint *ep,
+				  uint8_t *buffer, int buffer_length)
+{
+	snd_usbmidi_input_data(ep, 0, buffer, buffer_length);
+}
+
+static void snd_usbmidi_raw_output(struct snd_usb_midi_out_endpoint *ep,
+				   struct urb *urb)
+{
+	int count;
+
+	if (!ep->ports[0].active)
+		return;
+	count = snd_rawmidi_transmit(ep->ports[0].substream,
+				     urb->transfer_buffer,
+				     ep->max_transfer);
+	if (count < 1) {
+		ep->ports[0].active = 0;
+		return;
+	}
+	urb->transfer_buffer_length = count;
+}
+
+static const struct usb_protocol_ops snd_usbmidi_raw_ops = {
+	.input = snd_usbmidi_raw_input,
+	.output = snd_usbmidi_raw_output,
+};
+
+/*
+ * FTDI protocol: raw MIDI bytes, but input packets have two modem status bytes.
+ */
+
+static void snd_usbmidi_ftdi_input(struct snd_usb_midi_in_endpoint *ep,
+				   uint8_t *buffer, int buffer_length)
+{
+	if (buffer_length > 2)
+		snd_usbmidi_input_data(ep, 0, buffer + 2, buffer_length - 2);
+}
+
+static const struct usb_protocol_ops snd_usbmidi_ftdi_ops = {
+	.input = snd_usbmidi_ftdi_input,
+	.output = snd_usbmidi_raw_output,
+};
+
+static void snd_usbmidi_us122l_input(struct snd_usb_midi_in_endpoint *ep,
+				     uint8_t *buffer, int buffer_length)
+{
+	if (buffer_length != 9)
+		return;
+	buffer_length = 8;
+	while (buffer_length && buffer[buffer_length - 1] == 0xFD)
+		buffer_length--;
+	if (buffer_length)
+		snd_usbmidi_input_data(ep, 0, buffer, buffer_length);
+}
+
+static void snd_usbmidi_us122l_output(struct snd_usb_midi_out_endpoint *ep,
+				      struct urb *urb)
+{
+	int count;
+
+	if (!ep->ports[0].active)
+		return;
+	switch (snd_usb_get_speed(ep->umidi->dev)) {
+	case USB_SPEED_HIGH:
+	case USB_SPEED_SUPER:
+	case USB_SPEED_SUPER_PLUS:
+		count = 1;
+		break;
+	default:
+		count = 2;
+	}
+	if (ep->max_transfer < count)
+		return;
+	count = snd_rawmidi_transmit(ep->ports[0].substream,
+				     urb->transfer_buffer,
+				     count);
+	if (count < 1) {
+		ep->ports[0].active = 0;
+		return;
+	}
+
+	memset(urb->transfer_buffer + count, 0xFD, ep->max_transfer - count);
+	urb->transfer_buffer_length = ep->max_transfer;
+}
+
+static const struct usb_protocol_ops snd_usbmidi_122l_ops = {
+	.input = snd_usbmidi_us122l_input,
+	.output = snd_usbmidi_us122l_output,
+};
+
+/*
+ * Emagic USB MIDI protocol: raw MIDI with "F5 xx" port switching.
+ */
+
+static void snd_usbmidi_emagic_init_out(struct snd_usb_midi_out_endpoint *ep)
+{
+	static const u8 init_data[] = {
+		/* initialization magic: "get version" */
+		0xf0,
+		0x00, 0x20, 0x31,	/* Emagic */
+		0x64,			/* Unitor8 */
+		0x0b,			/* version number request */
+		0x00,			/* command version */
+		0x00,			/* EEPROM, box 0 */
+		0xf7
+	};
+	send_bulk_static_data(ep, init_data, sizeof(init_data));
+	/* while we're at it, pour on more magic */
+	send_bulk_static_data(ep, init_data, sizeof(init_data));
+}
+
+static void snd_usbmidi_emagic_finish_out(struct snd_usb_midi_out_endpoint *ep)
+{
+	static const u8 finish_data[] = {
+		/* switch to patch mode with last preset */
+		0xf0,
+		0x00, 0x20, 0x31,	/* Emagic */
+		0x64,			/* Unitor8 */
+		0x10,			/* patch switch command */
+		0x00,			/* command version */
+		0x7f,			/* to all boxes */
+		0x40,			/* last preset in EEPROM */
+		0xf7
+	};
+	send_bulk_static_data(ep, finish_data, sizeof(finish_data));
+}
+
+static void snd_usbmidi_emagic_input(struct snd_usb_midi_in_endpoint *ep,
+				     uint8_t *buffer, int buffer_length)
+{
+	int i;
+
+	/* FF indicates end of valid data */
+	for (i = 0; i < buffer_length; ++i)
+		if (buffer[i] == 0xff) {
+			buffer_length = i;
+			break;
+		}
+
+	/* handle F5 at end of last buffer */
+	if (ep->seen_f5)
+		goto switch_port;
+
+	while (buffer_length > 0) {
+		/* determine size of data until next F5 */
+		for (i = 0; i < buffer_length; ++i)
+			if (buffer[i] == 0xf5)
+				break;
+		snd_usbmidi_input_data(ep, ep->current_port, buffer, i);
+		buffer += i;
+		buffer_length -= i;
+
+		if (buffer_length <= 0)
+			break;
+		/* assert(buffer[0] == 0xf5); */
+		ep->seen_f5 = 1;
+		++buffer;
+		--buffer_length;
+
+	switch_port:
+		if (buffer_length <= 0)
+			break;
+		if (buffer[0] < 0x80) {
+			ep->current_port = (buffer[0] - 1) & 15;
+			++buffer;
+			--buffer_length;
+		}
+		ep->seen_f5 = 0;
+	}
+}
+
+static void snd_usbmidi_emagic_output(struct snd_usb_midi_out_endpoint *ep,
+				      struct urb *urb)
+{
+	int port0 = ep->current_port;
+	uint8_t *buf = urb->transfer_buffer;
+	int buf_free = ep->max_transfer;
+	int length, i;
+
+	for (i = 0; i < 0x10; ++i) {
+		/* round-robin, starting at the last current port */
+		int portnum = (port0 + i) & 15;
+		struct usbmidi_out_port *port = &ep->ports[portnum];
+
+		if (!port->active)
+			continue;
+		if (snd_rawmidi_transmit_peek(port->substream, buf, 1) != 1) {
+			port->active = 0;
+			continue;
+		}
+
+		if (portnum != ep->current_port) {
+			if (buf_free < 2)
+				break;
+			ep->current_port = portnum;
+			buf[0] = 0xf5;
+			buf[1] = (portnum + 1) & 15;
+			buf += 2;
+			buf_free -= 2;
+		}
+
+		if (buf_free < 1)
+			break;
+		length = snd_rawmidi_transmit(port->substream, buf, buf_free);
+		if (length > 0) {
+			buf += length;
+			buf_free -= length;
+			if (buf_free < 1)
+				break;
+		}
+	}
+	if (buf_free < ep->max_transfer && buf_free > 0) {
+		*buf = 0xff;
+		--buf_free;
+	}
+	urb->transfer_buffer_length = ep->max_transfer - buf_free;
+}
+
+static const struct usb_protocol_ops snd_usbmidi_emagic_ops = {
+	.input = snd_usbmidi_emagic_input,
+	.output = snd_usbmidi_emagic_output,
+	.init_out_endpoint = snd_usbmidi_emagic_init_out,
+	.finish_out_endpoint = snd_usbmidi_emagic_finish_out,
+};
+
+
+static void update_roland_altsetting(struct snd_usb_midi *umidi)
+{
+	struct usb_interface *intf;
+	struct usb_host_interface *hostif;
+	struct usb_interface_descriptor *intfd;
+	int is_light_load;
+
+	intf = umidi->iface;
+	is_light_load = intf->cur_altsetting != intf->altsetting;
+	if (umidi->roland_load_ctl->private_value == is_light_load)
+		return;
+	hostif = &intf->altsetting[umidi->roland_load_ctl->private_value];
+	intfd = get_iface_desc(hostif);
+	snd_usbmidi_input_stop(&umidi->list);
+	usb_set_interface(umidi->dev, intfd->bInterfaceNumber,
+			  intfd->bAlternateSetting);
+	snd_usbmidi_input_start(&umidi->list);
+}
+
+static int substream_open(struct snd_rawmidi_substream *substream, int dir,
+			  int open)
+{
+	struct snd_usb_midi *umidi = substream->rmidi->private_data;
+	struct snd_kcontrol *ctl;
+
+	guard(rwsem_read)(&umidi->disc_rwsem);
+	if (umidi->disconnected)
+		return open ? -ENODEV : 0;
+
+	guard(mutex)(&umidi->mutex);
+	if (open) {
+		if (!umidi->opened[0] && !umidi->opened[1]) {
+			if (umidi->roland_load_ctl) {
+				ctl = umidi->roland_load_ctl;
+				ctl->vd[0].access |=
+					SNDRV_CTL_ELEM_ACCESS_INACTIVE;
+				snd_ctl_notify(umidi->card,
+				       SNDRV_CTL_EVENT_MASK_INFO, &ctl->id);
+				update_roland_altsetting(umidi);
+			}
+		}
+		umidi->opened[dir]++;
+		if (umidi->opened[1])
+			snd_usbmidi_input_start(&umidi->list);
+	} else {
+		umidi->opened[dir]--;
+		if (!umidi->opened[1])
+			snd_usbmidi_input_stop(&umidi->list);
+		if (!umidi->opened[0] && !umidi->opened[1]) {
+			if (umidi->roland_load_ctl) {
+				ctl = umidi->roland_load_ctl;
+				ctl->vd[0].access &=
+					~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
+				snd_ctl_notify(umidi->card,
+				       SNDRV_CTL_EVENT_MASK_INFO, &ctl->id);
+			}
+		}
+	}
+	return 0;
+}
+
+static int snd_usbmidi_output_open(struct snd_rawmidi_substream *substream)
+{
+	struct snd_usb_midi *umidi = substream->rmidi->private_data;
+	struct usbmidi_out_port *port = NULL;
+	int i, j;
+
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i)
+		if (umidi->endpoints[i].out)
+			for (j = 0; j < 0x10; ++j)
+				if (umidi->endpoints[i].out->ports[j].substream == substream) {
+					port = &umidi->endpoints[i].out->ports[j];
+					break;
+				}
+	if (!port)
+		return -ENXIO;
+
+	substream->runtime->private_data = port;
+	port->state = STATE_UNKNOWN;
+	return substream_open(substream, 0, 1);
+}
+
+static int snd_usbmidi_output_close(struct snd_rawmidi_substream *substream)
+{
+	struct usbmidi_out_port *port = substream->runtime->private_data;
+
+	flush_work(&port->ep->work);
+	return substream_open(substream, 0, 0);
+}
+
+static void snd_usbmidi_output_trigger(struct snd_rawmidi_substream *substream,
+				       int up)
+{
+	struct usbmidi_out_port *port =
+		(struct usbmidi_out_port *)substream->runtime->private_data;
+
+	port->active = up;
+	if (up) {
+		if (port->ep->umidi->disconnected) {
+			/* gobble up remaining bytes to prevent wait in
+			 * snd_rawmidi_drain_output */
+			snd_rawmidi_proceed(substream);
+			return;
+		}
+		queue_work(system_highpri_wq, &port->ep->work);
+	}
+}
+
+static void snd_usbmidi_output_drain(struct snd_rawmidi_substream *substream)
+{
+	struct usbmidi_out_port *port = substream->runtime->private_data;
+	struct snd_usb_midi_out_endpoint *ep = port->ep;
+	unsigned int drain_urbs;
+	DEFINE_WAIT(wait);
+	long timeout = msecs_to_jiffies(50);
+
+	if (ep->umidi->disconnected)
+		return;
+	/*
+	 * The substream buffer is empty, but some data might still be in the
+	 * currently active URBs, so we have to wait for those to complete.
+	 */
+	spin_lock_irq(&ep->buffer_lock);
+	drain_urbs = ep->active_urbs;
+	if (drain_urbs) {
+		ep->drain_urbs |= drain_urbs;
+		do {
+			prepare_to_wait(&ep->drain_wait, &wait,
+					TASK_UNINTERRUPTIBLE);
+			spin_unlock_irq(&ep->buffer_lock);
+			timeout = schedule_timeout(timeout);
+			spin_lock_irq(&ep->buffer_lock);
+			drain_urbs &= ep->drain_urbs;
+		} while (drain_urbs && timeout);
+		finish_wait(&ep->drain_wait, &wait);
+	}
+	port->active = 0;
+	spin_unlock_irq(&ep->buffer_lock);
+}
+
+static int snd_usbmidi_input_open(struct snd_rawmidi_substream *substream)
+{
+	return substream_open(substream, 1, 1);
+}
+
+static int snd_usbmidi_input_close(struct snd_rawmidi_substream *substream)
+{
+	return substream_open(substream, 1, 0);
+}
+
+static void snd_usbmidi_input_trigger(struct snd_rawmidi_substream *substream,
+				      int up)
+{
+	struct snd_usb_midi *umidi = substream->rmidi->private_data;
+
+	if (up)
+		set_bit(substream->number, &umidi->input_triggered);
+	else
+		clear_bit(substream->number, &umidi->input_triggered);
+}
+
+static const struct snd_rawmidi_ops snd_usbmidi_output_ops = {
+	.open = snd_usbmidi_output_open,
+	.close = snd_usbmidi_output_close,
+	.trigger = snd_usbmidi_output_trigger,
+	.drain = snd_usbmidi_output_drain,
+};
+
+static const struct snd_rawmidi_ops snd_usbmidi_input_ops = {
+	.open = snd_usbmidi_input_open,
+	.close = snd_usbmidi_input_close,
+	.trigger = snd_usbmidi_input_trigger
+};
+
+static void free_urb_and_buffer(struct snd_usb_midi *umidi, struct urb *urb,
+				unsigned int buffer_length)
+{
+	usb_free_coherent(umidi->dev, buffer_length,
+			  urb->transfer_buffer, urb->transfer_dma);
+	usb_free_urb(urb);
+}
+
+/*
+ * Frees an input endpoint.
+ * May be called when ep hasn't been initialized completely.
+ */
+static void snd_usbmidi_in_endpoint_delete(struct snd_usb_midi_in_endpoint *ep)
+{
+	unsigned int i;
+
+	for (i = 0; i < INPUT_URBS; ++i)
+		if (ep->urbs[i])
+			free_urb_and_buffer(ep->umidi, ep->urbs[i],
+					    ep->urbs[i]->transfer_buffer_length);
+	kfree(ep);
+}
+
+/*
+ * Creates an input endpoint.
+ */
+static int snd_usbmidi_in_endpoint_create(struct snd_usb_midi *umidi,
+					  struct snd_usb_midi_endpoint_info *ep_info,
+					  struct snd_usb_midi_endpoint *rep)
+{
+	struct snd_usb_midi_in_endpoint *ep;
+	void *buffer;
+	unsigned int pipe;
+	int length;
+	unsigned int i;
+	int err;
+
+	rep->in = NULL;
+	ep = kzalloc_obj(*ep);
+	if (!ep)
+		return -ENOMEM;
+	ep->umidi = umidi;
+
+	for (i = 0; i < INPUT_URBS; ++i) {
+		ep->urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
+		if (!ep->urbs[i]) {
+			err = -ENOMEM;
+			goto error;
+		}
+	}
+	if (ep_info->in_interval)
+		pipe = usb_rcvintpipe(umidi->dev, ep_info->in_ep);
+	else
+		pipe = usb_rcvbulkpipe(umidi->dev, ep_info->in_ep);
+	length = usb_maxpacket(umidi->dev, pipe);
+	for (i = 0; i < INPUT_URBS; ++i) {
+		buffer = usb_alloc_coherent(umidi->dev, length, GFP_KERNEL,
+					    &ep->urbs[i]->transfer_dma);
+		if (!buffer) {
+			err = -ENOMEM;
+			goto error;
+		}
+		if (ep_info->in_interval)
+			usb_fill_int_urb(ep->urbs[i], umidi->dev,
+					 pipe, buffer, length,
+					 snd_usbmidi_in_urb_complete,
+					 ep, ep_info->in_interval);
+		else
+			usb_fill_bulk_urb(ep->urbs[i], umidi->dev,
+					  pipe, buffer, length,
+					  snd_usbmidi_in_urb_complete, ep);
+		ep->urbs[i]->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+		err = usb_urb_ep_type_check(ep->urbs[i]);
+		if (err < 0) {
+			dev_err(&umidi->dev->dev, "invalid MIDI in EP %x\n",
+				ep_info->in_ep);
+			goto error;
+		}
+	}
+
+	rep->in = ep;
+	return 0;
+
+ error:
+	snd_usbmidi_in_endpoint_delete(ep);
+	return err;
+}
+
+/*
+ * Frees an output endpoint.
+ * May be called when ep hasn't been initialized completely.
+ */
+static void snd_usbmidi_out_endpoint_clear(struct snd_usb_midi_out_endpoint *ep)
+{
+	unsigned int i;
+
+	for (i = 0; i < OUTPUT_URBS; ++i)
+		if (ep->urbs[i].urb) {
+			free_urb_and_buffer(ep->umidi, ep->urbs[i].urb,
+					    ep->max_transfer);
+			ep->urbs[i].urb = NULL;
+		}
+}
+
+static void snd_usbmidi_out_endpoint_delete(struct snd_usb_midi_out_endpoint *ep)
+{
+	snd_usbmidi_out_endpoint_clear(ep);
+	kfree(ep);
+}
+
+/*
+ * Creates an output endpoint, and initializes output ports.
+ */
+static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi *umidi,
+					   struct snd_usb_midi_endpoint_info *ep_info,
+					   struct snd_usb_midi_endpoint *rep)
+{
+	struct snd_usb_midi_out_endpoint *ep;
+	unsigned int i;
+	unsigned int pipe;
+	void *buffer;
+	int err;
+
+	rep->out = NULL;
+	ep = kzalloc_obj(*ep);
+	if (!ep)
+		return -ENOMEM;
+	ep->umidi = umidi;
+
+	for (i = 0; i < OUTPUT_URBS; ++i) {
+		ep->urbs[i].urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!ep->urbs[i].urb) {
+			err = -ENOMEM;
+			goto error;
+		}
+		ep->urbs[i].ep = ep;
+	}
+	if (ep_info->out_interval)
+		pipe = usb_sndintpipe(umidi->dev, ep_info->out_ep);
+	else
+		pipe = usb_sndbulkpipe(umidi->dev, ep_info->out_ep);
+	switch (umidi->usb_id) {
+	default:
+		ep->max_transfer = usb_maxpacket(umidi->dev, pipe);
+		break;
+		/*
+		 * Various chips declare a packet size larger than 4 bytes, but
+		 * do not actually work with larger packets:
+		 */
+	case USB_ID(0x0a67, 0x5011): /* Medeli DD305 */
+	case USB_ID(0x0a92, 0x1020): /* ESI M4U */
+	case USB_ID(0x1430, 0x474b): /* RedOctane GH MIDI INTERFACE */
+	case USB_ID(0x15ca, 0x0101): /* Textech USB Midi Cable */
+	case USB_ID(0x15ca, 0x1806): /* Textech USB Midi Cable */
+	case USB_ID(0x1a86, 0x752d): /* QinHeng CH345 "USB2.0-MIDI" */
+	case USB_ID(0xfc08, 0x0101): /* Unknown vendor Cable */
+		ep->max_transfer = 4;
+		break;
+		/*
+		 * Some devices only work with 9 bytes packet size:
+		 */
+	case USB_ID(0x0644, 0x800e): /* Tascam US-122L */
+	case USB_ID(0x0644, 0x800f): /* Tascam US-144 */
+		ep->max_transfer = 9;
+		break;
+	}
+	for (i = 0; i < OUTPUT_URBS; ++i) {
+		buffer = usb_alloc_coherent(umidi->dev,
+					    ep->max_transfer, GFP_KERNEL,
+					    &ep->urbs[i].urb->transfer_dma);
+		if (!buffer) {
+			err = -ENOMEM;
+			goto error;
+		}
+		if (ep_info->out_interval)
+			usb_fill_int_urb(ep->urbs[i].urb, umidi->dev,
+					 pipe, buffer, ep->max_transfer,
+					 snd_usbmidi_out_urb_complete,
+					 &ep->urbs[i], ep_info->out_interval);
+		else
+			usb_fill_bulk_urb(ep->urbs[i].urb, umidi->dev,
+					  pipe, buffer, ep->max_transfer,
+					  snd_usbmidi_out_urb_complete,
+					  &ep->urbs[i]);
+		err = usb_urb_ep_type_check(ep->urbs[i].urb);
+		if (err < 0) {
+			dev_err(&umidi->dev->dev, "invalid MIDI out EP %x\n",
+				ep_info->out_ep);
+			goto error;
+		}
+		ep->urbs[i].urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+	}
+
+	spin_lock_init(&ep->buffer_lock);
+	INIT_WORK(&ep->work, snd_usbmidi_out_work);
+	init_waitqueue_head(&ep->drain_wait);
+
+	for (i = 0; i < 0x10; ++i)
+		if (ep_info->out_cables & (1 << i)) {
+			ep->ports[i].ep = ep;
+			ep->ports[i].cable = i << 4;
+		}
+
+	if (umidi->usb_protocol_ops->init_out_endpoint)
+		umidi->usb_protocol_ops->init_out_endpoint(ep);
+
+	rep->out = ep;
+	return 0;
+
+ error:
+	snd_usbmidi_out_endpoint_delete(ep);
+	return err;
+}
+
+/*
+ * Frees everything.
+ */
+static void snd_usbmidi_free(struct snd_usb_midi *umidi)
+{
+	int i;
+
+	if (!umidi->disconnected)
+		snd_usbmidi_disconnect(&umidi->list);
+
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
+		struct snd_usb_midi_endpoint *ep = &umidi->endpoints[i];
+		kfree(ep->out);
+	}
+	mutex_destroy(&umidi->mutex);
+	kfree(umidi);
+}
+
+/*
+ * Unlinks all URBs (must be done before the usb_device is deleted).
+ */
+void snd_usbmidi_disconnect(struct list_head *p)
+{
+	struct snd_usb_midi *umidi;
+	unsigned int i, j;
+
+	umidi = list_entry(p, struct snd_usb_midi, list);
+	/*
+	 * an URB's completion handler may start the timer and
+	 * a timer may submit an URB. To reliably break the cycle
+	 * a flag under lock must be used
+	 */
+	scoped_guard(rwsem_write, &umidi->disc_rwsem) {
+		guard(spinlock_irq)(&umidi->disc_lock);
+		umidi->disconnected = 1;
+	}
+
+	timer_shutdown_sync(&umidi->error_timer);
+
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
+		struct snd_usb_midi_endpoint *ep = &umidi->endpoints[i];
+		if (ep->out)
+			cancel_work_sync(&ep->out->work);
+		if (ep->out) {
+			for (j = 0; j < OUTPUT_URBS; ++j)
+				usb_kill_urb(ep->out->urbs[j].urb);
+			if (umidi->usb_protocol_ops->finish_out_endpoint)
+				umidi->usb_protocol_ops->finish_out_endpoint(ep->out);
+			ep->out->active_urbs = 0;
+			if (ep->out->drain_urbs) {
+				ep->out->drain_urbs = 0;
+				wake_up(&ep->out->drain_wait);
+			}
+		}
+		if (ep->in)
+			for (j = 0; j < INPUT_URBS; ++j)
+				usb_kill_urb(ep->in->urbs[j]);
+		/* free endpoints here; later call can result in Oops */
+		if (ep->out)
+			snd_usbmidi_out_endpoint_clear(ep->out);
+		if (ep->in) {
+			snd_usbmidi_in_endpoint_delete(ep->in);
+			ep->in = NULL;
+		}
+	}
+}
+EXPORT_SYMBOL(snd_usbmidi_disconnect);
+
+static void snd_usbmidi_rawmidi_free(struct snd_rawmidi *rmidi)
+{
+	struct snd_usb_midi *umidi = rmidi->private_data;
+	snd_usbmidi_free(umidi);
+}
+
+static struct snd_rawmidi_substream *snd_usbmidi_find_substream(struct snd_usb_midi *umidi,
+								int stream,
+								int number)
+{
+	struct snd_rawmidi_substream *substream;
+
+	list_for_each_entry(substream, &umidi->rmidi->streams[stream].substreams,
+			    list) {
+		if (substream->number == number)
+			return substream;
+	}
+	return NULL;
+}
+
+/*
+ * This list specifies names for ports that do not fit into the standard
+ * "(product) MIDI (n)" schema because they aren't external MIDI ports,
+ * such as internal control or synthesizer ports.
+ */
+static struct port_info {
+	u32 id;
+	short int port;
+	short int voices;
+	const char *name;
+	unsigned int seq_flags;
+} snd_usbmidi_port_info[] = {
+#define PORT_INFO(vendor, product, num, name_, voices_, flags) \
+	{ .id = USB_ID(vendor, product), \
+	  .port = num, .voices = voices_, \
+	  .name = name_, .seq_flags = flags }
+#define EXTERNAL_PORT(vendor, product, num, name) \
+	PORT_INFO(vendor, product, num, name, 0, \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC | \
+		  SNDRV_SEQ_PORT_TYPE_HARDWARE | \
+		  SNDRV_SEQ_PORT_TYPE_PORT)
+#define CONTROL_PORT(vendor, product, num, name) \
+	PORT_INFO(vendor, product, num, name, 0, \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC | \
+		  SNDRV_SEQ_PORT_TYPE_HARDWARE)
+#define GM_SYNTH_PORT(vendor, product, num, name, voices) \
+	PORT_INFO(vendor, product, num, name, voices, \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GM | \
+		  SNDRV_SEQ_PORT_TYPE_HARDWARE | \
+		  SNDRV_SEQ_PORT_TYPE_SYNTHESIZER)
+#define ROLAND_SYNTH_PORT(vendor, product, num, name, voices) \
+	PORT_INFO(vendor, product, num, name, voices, \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GM | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GM2 | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GS | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_XG | \
+		  SNDRV_SEQ_PORT_TYPE_HARDWARE | \
+		  SNDRV_SEQ_PORT_TYPE_SYNTHESIZER)
+#define SOUNDCANVAS_PORT(vendor, product, num, name, voices) \
+	PORT_INFO(vendor, product, num, name, voices, \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GM | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GM2 | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_GS | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_XG | \
+		  SNDRV_SEQ_PORT_TYPE_MIDI_MT32 | \
+		  SNDRV_SEQ_PORT_TYPE_HARDWARE | \
+		  SNDRV_SEQ_PORT_TYPE_SYNTHESIZER)
+	/* Yamaha MOTIF XF */
+	GM_SYNTH_PORT(0x0499, 0x105c, 0, "%s Tone Generator", 128),
+	CONTROL_PORT(0x0499, 0x105c, 1, "%s Remote Control"),
+	EXTERNAL_PORT(0x0499, 0x105c, 2, "%s Thru"),
+	CONTROL_PORT(0x0499, 0x105c, 3, "%s Editor"),
+	/* Roland UA-100 */
+	CONTROL_PORT(0x0582, 0x0000, 2, "%s Control"),
+	/* Roland SC-8850 */
+	SOUNDCANVAS_PORT(0x0582, 0x0003, 0, "%s Part A", 128),
+	SOUNDCANVAS_PORT(0x0582, 0x0003, 1, "%s Part B", 128),
+	SOUNDCANVAS_PORT(0x0582, 0x0003, 2, "%s Part C", 128),
+	SOUNDCANVAS_PORT(0x0582, 0x0003, 3, "%s Part D", 128),
+	EXTERNAL_PORT(0x0582, 0x0003, 4, "%s MIDI 1"),
+	EXTERNAL_PORT(0x0582, 0x0003, 5, "%s MIDI 2"),
+	/* Roland U-8 */
+	EXTERNAL_PORT(0x0582, 0x0004, 0, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x0004, 1, "%s Control"),
+	/* Roland SC-8820 */
+	SOUNDCANVAS_PORT(0x0582, 0x0007, 0, "%s Part A", 64),
+	SOUNDCANVAS_PORT(0x0582, 0x0007, 1, "%s Part B", 64),
+	EXTERNAL_PORT(0x0582, 0x0007, 2, "%s MIDI"),
+	/* Roland SK-500 */
+	SOUNDCANVAS_PORT(0x0582, 0x000b, 0, "%s Part A", 64),
+	SOUNDCANVAS_PORT(0x0582, 0x000b, 1, "%s Part B", 64),
+	EXTERNAL_PORT(0x0582, 0x000b, 2, "%s MIDI"),
+	/* Roland SC-D70 */
+	SOUNDCANVAS_PORT(0x0582, 0x000c, 0, "%s Part A", 64),
+	SOUNDCANVAS_PORT(0x0582, 0x000c, 1, "%s Part B", 64),
+	EXTERNAL_PORT(0x0582, 0x000c, 2, "%s MIDI"),
+	/* Edirol UM-880 */
+	CONTROL_PORT(0x0582, 0x0014, 8, "%s Control"),
+	/* Edirol SD-90 */
+	ROLAND_SYNTH_PORT(0x0582, 0x0016, 0, "%s Part A", 128),
+	ROLAND_SYNTH_PORT(0x0582, 0x0016, 1, "%s Part B", 128),
+	EXTERNAL_PORT(0x0582, 0x0016, 2, "%s MIDI 1"),
+	EXTERNAL_PORT(0x0582, 0x0016, 3, "%s MIDI 2"),
+	/* Edirol UM-550 */
+	CONTROL_PORT(0x0582, 0x0023, 5, "%s Control"),
+	/* Edirol SD-20 */
+	ROLAND_SYNTH_PORT(0x0582, 0x0027, 0, "%s Part A", 64),
+	ROLAND_SYNTH_PORT(0x0582, 0x0027, 1, "%s Part B", 64),
+	EXTERNAL_PORT(0x0582, 0x0027, 2, "%s MIDI"),
+	/* Edirol SD-80 */
+	ROLAND_SYNTH_PORT(0x0582, 0x0029, 0, "%s Part A", 128),
+	ROLAND_SYNTH_PORT(0x0582, 0x0029, 1, "%s Part B", 128),
+	EXTERNAL_PORT(0x0582, 0x0029, 2, "%s MIDI 1"),
+	EXTERNAL_PORT(0x0582, 0x0029, 3, "%s MIDI 2"),
+	/* Edirol UA-700 */
+	EXTERNAL_PORT(0x0582, 0x002b, 0, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x002b, 1, "%s Control"),
+	/* Roland VariOS */
+	EXTERNAL_PORT(0x0582, 0x002f, 0, "%s MIDI"),
+	EXTERNAL_PORT(0x0582, 0x002f, 1, "%s External MIDI"),
+	EXTERNAL_PORT(0x0582, 0x002f, 2, "%s Sync"),
+	/* Edirol PCR */
+	EXTERNAL_PORT(0x0582, 0x0033, 0, "%s MIDI"),
+	EXTERNAL_PORT(0x0582, 0x0033, 1, "%s 1"),
+	EXTERNAL_PORT(0x0582, 0x0033, 2, "%s 2"),
+	/* BOSS GS-10 */
+	EXTERNAL_PORT(0x0582, 0x003b, 0, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x003b, 1, "%s Control"),
+	/* Edirol UA-1000 */
+	EXTERNAL_PORT(0x0582, 0x0044, 0, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x0044, 1, "%s Control"),
+	/* Edirol UR-80 */
+	EXTERNAL_PORT(0x0582, 0x0048, 0, "%s MIDI"),
+	EXTERNAL_PORT(0x0582, 0x0048, 1, "%s 1"),
+	EXTERNAL_PORT(0x0582, 0x0048, 2, "%s 2"),
+	/* Edirol PCR-A */
+	EXTERNAL_PORT(0x0582, 0x004d, 0, "%s MIDI"),
+	EXTERNAL_PORT(0x0582, 0x004d, 1, "%s 1"),
+	EXTERNAL_PORT(0x0582, 0x004d, 2, "%s 2"),
+	/* BOSS GT-PRO */
+	CONTROL_PORT(0x0582, 0x0089, 0, "%s Control"),
+	/* Edirol UM-3EX */
+	CONTROL_PORT(0x0582, 0x009a, 3, "%s Control"),
+	/* Roland VG-99 */
+	CONTROL_PORT(0x0582, 0x00b2, 0, "%s Control"),
+	EXTERNAL_PORT(0x0582, 0x00b2, 1, "%s MIDI"),
+	/* Cakewalk Sonar V-Studio 100 */
+	EXTERNAL_PORT(0x0582, 0x00eb, 0, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x00eb, 1, "%s Control"),
+	/* Roland VB-99 */
+	CONTROL_PORT(0x0582, 0x0102, 0, "%s Control"),
+	EXTERNAL_PORT(0x0582, 0x0102, 1, "%s MIDI"),
+	/* Roland A-PRO */
+	EXTERNAL_PORT(0x0582, 0x010f, 0, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x010f, 1, "%s 1"),
+	CONTROL_PORT(0x0582, 0x010f, 2, "%s 2"),
+	/* Roland SD-50 */
+	ROLAND_SYNTH_PORT(0x0582, 0x0114, 0, "%s Synth", 128),
+	EXTERNAL_PORT(0x0582, 0x0114, 1, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x0114, 2, "%s Control"),
+	/* Roland OCTA-CAPTURE */
+	EXTERNAL_PORT(0x0582, 0x0120, 0, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x0120, 1, "%s Control"),
+	EXTERNAL_PORT(0x0582, 0x0121, 0, "%s MIDI"),
+	CONTROL_PORT(0x0582, 0x0121, 1, "%s Control"),
+	/* Roland SPD-SX */
+	CONTROL_PORT(0x0582, 0x0145, 0, "%s Control"),
+	EXTERNAL_PORT(0x0582, 0x0145, 1, "%s MIDI"),
+	/* Roland A-Series */
+	CONTROL_PORT(0x0582, 0x0156, 0, "%s Keyboard"),
+	EXTERNAL_PORT(0x0582, 0x0156, 1, "%s MIDI"),
+	/* Roland INTEGRA-7 */
+	ROLAND_SYNTH_PORT(0x0582, 0x015b, 0, "%s Synth", 128),
+	CONTROL_PORT(0x0582, 0x015b, 1, "%s Control"),
+	/* M-Audio MidiSport 8x8 */
+	CONTROL_PORT(0x0763, 0x1031, 8, "%s Control"),
+	CONTROL_PORT(0x0763, 0x1033, 8, "%s Control"),
+	/* MOTU Fastlane */
+	EXTERNAL_PORT(0x07fd, 0x0001, 0, "%s MIDI A"),
+	EXTERNAL_PORT(0x07fd, 0x0001, 1, "%s MIDI B"),
+	/* Emagic Unitor8/AMT8/MT4 */
+	EXTERNAL_PORT(0x086a, 0x0001, 8, "%s Broadcast"),
+	EXTERNAL_PORT(0x086a, 0x0002, 8, "%s Broadcast"),
+	EXTERNAL_PORT(0x086a, 0x0003, 4, "%s Broadcast"),
+	/* Akai MPD16 */
+	CONTROL_PORT(0x09e8, 0x0062, 0, "%s Control"),
+	PORT_INFO(0x09e8, 0x0062, 1, "%s MIDI", 0,
+		SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC |
+		SNDRV_SEQ_PORT_TYPE_HARDWARE),
+	/* Access Music Virus TI */
+	EXTERNAL_PORT(0x133e, 0x0815, 0, "%s MIDI"),
+	PORT_INFO(0x133e, 0x0815, 1, "%s Synth", 0,
+		SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC |
+		SNDRV_SEQ_PORT_TYPE_HARDWARE |
+		SNDRV_SEQ_PORT_TYPE_SYNTHESIZER),
+};
+
+static struct port_info *find_port_info(struct snd_usb_midi *umidi, int number)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(snd_usbmidi_port_info); ++i) {
+		if (snd_usbmidi_port_info[i].id == umidi->usb_id &&
+		    snd_usbmidi_port_info[i].port == number)
+			return &snd_usbmidi_port_info[i];
+	}
+	return NULL;
+}
+
+static void snd_usbmidi_get_port_info(struct snd_rawmidi *rmidi, int number,
+				      struct snd_seq_port_info *seq_port_info)
+{
+	struct snd_usb_midi *umidi = rmidi->private_data;
+	struct port_info *port_info;
+
+	/* TODO: read port flags from descriptors */
+	port_info = find_port_info(umidi, number);
+	if (port_info) {
+		seq_port_info->type = port_info->seq_flags;
+		seq_port_info->midi_voices = port_info->voices;
+	}
+}
+
+/* return iJack for the corresponding jackID */
+static int find_usb_ijack(struct usb_host_interface *hostif, uint8_t jack_id)
+{
+	unsigned char *extra = hostif->extra;
+	int extralen = hostif->extralen;
+	struct usb_descriptor_header *h;
+	struct usb_midi_out_jack_descriptor *outjd;
+	struct usb_midi_in_jack_descriptor *injd;
+	size_t sz;
+
+	while (extralen > 4) {
+		h = (struct usb_descriptor_header *)extra;
+		if (h->bDescriptorType != USB_DT_CS_INTERFACE)
+			goto next;
+
+		outjd = (struct usb_midi_out_jack_descriptor *)h;
+		if (h->bLength >= sizeof(*outjd) &&
+		    outjd->bDescriptorSubtype == UAC_MIDI_OUT_JACK &&
+		    outjd->bJackID == jack_id) {
+			sz = USB_DT_MIDI_OUT_SIZE(outjd->bNrInputPins);
+			if (outjd->bLength < sz)
+				goto next;
+			return *(extra + sz - 1);
+		}
+
+		injd = (struct usb_midi_in_jack_descriptor *)h;
+		if (injd->bLength >= sizeof(*injd) &&
+		    injd->bDescriptorSubtype == UAC_MIDI_IN_JACK &&
+		    injd->bJackID == jack_id)
+			return injd->iJack;
+
+next:
+		if (!extra[0])
+			break;
+		extralen -= extra[0];
+		extra += extra[0];
+	}
+	return 0;
+}
+
+static void snd_usbmidi_init_substream(struct snd_usb_midi *umidi,
+				       int stream, int number, int jack_id,
+				       struct snd_rawmidi_substream **rsubstream)
+{
+	struct port_info *port_info;
+	const char *name_format;
+	struct usb_interface *intf;
+	struct usb_host_interface *hostif;
+	uint8_t jack_name_buf[32];
+	uint8_t *default_jack_name = "MIDI";
+	uint8_t *jack_name = default_jack_name;
+	uint8_t iJack;
+	int res;
+
+	struct snd_rawmidi_substream *substream =
+		snd_usbmidi_find_substream(umidi, stream, number);
+	if (!substream) {
+		dev_err(&umidi->dev->dev, "substream %d:%d not found\n", stream,
+			number);
+		return;
+	}
+
+	intf = umidi->iface;
+	if (intf && jack_id >= 0) {
+		hostif = intf->cur_altsetting;
+		iJack = find_usb_ijack(hostif, jack_id);
+		if (iJack != 0) {
+			res = usb_string(umidi->dev, iJack, jack_name_buf,
+			  ARRAY_SIZE(jack_name_buf));
+			if (res)
+				jack_name = jack_name_buf;
+		}
+	}
+
+	port_info = find_port_info(umidi, number);
+	if (port_info || jack_name == default_jack_name ||
+	    strncmp(umidi->card->shortname, jack_name, strlen(umidi->card->shortname)) != 0) {
+		name_format = port_info ? port_info->name :
+			(jack_name != default_jack_name  ? "%s %s" : "%s %s %d");
+		snprintf(substream->name, sizeof(substream->name),
+			 name_format, umidi->card->shortname, jack_name, number + 1);
+	} else {
+		/* The manufacturer included the iProduct name in the jack
+		 * name, do not use both
+		 */
+		strscpy(substream->name, jack_name);
+	}
+
+	*rsubstream = substream;
+}
+
+/*
+ * Creates the endpoints and their ports.
+ */
+static int snd_usbmidi_create_endpoints(struct snd_usb_midi *umidi,
+					struct snd_usb_midi_endpoint_info *endpoints)
+{
+	int i, j, err;
+	int out_ports = 0, in_ports = 0;
+
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
+		if (endpoints[i].out_cables) {
+			err = snd_usbmidi_out_endpoint_create(umidi,
+							      &endpoints[i],
+							      &umidi->endpoints[i]);
+			if (err < 0)
+				return err;
+		}
+		if (endpoints[i].in_cables) {
+			err = snd_usbmidi_in_endpoint_create(umidi,
+							     &endpoints[i],
+							     &umidi->endpoints[i]);
+			if (err < 0)
+				return err;
+		}
+
+		for (j = 0; j < 0x10; ++j) {
+			if (endpoints[i].out_cables & (1 << j)) {
+				snd_usbmidi_init_substream(umidi,
+							   SNDRV_RAWMIDI_STREAM_OUTPUT,
+							   out_ports,
+							   endpoints[i].assoc_out_jacks[j],
+							   &umidi->endpoints[i].out->ports[j].substream);
+				++out_ports;
+			}
+			if (endpoints[i].in_cables & (1 << j)) {
+				snd_usbmidi_init_substream(umidi,
+							   SNDRV_RAWMIDI_STREAM_INPUT,
+							   in_ports,
+							   endpoints[i].assoc_in_jacks[j],
+							   &umidi->endpoints[i].in->ports[j].substream);
+				++in_ports;
+			}
+		}
+	}
+	dev_dbg(&umidi->dev->dev, "created %d output and %d input ports\n",
+		    out_ports, in_ports);
+	return 0;
+}
+
+static struct usb_ms_endpoint_descriptor *find_usb_ms_endpoint_descriptor(
+					struct usb_host_endpoint *hostep)
+{
+	unsigned char *extra = hostep->extra;
+	int extralen = hostep->extralen;
+
+	while (extralen > 3) {
+		struct usb_ms_endpoint_descriptor *ms_ep =
+				(struct usb_ms_endpoint_descriptor *)extra;
+		int length = ms_ep->bLength;
+
+		if (!length || length > extralen)
+			break;
+
+		if (length > 3 &&
+		    ms_ep->bDescriptorType == USB_DT_CS_ENDPOINT &&
+		    ms_ep->bDescriptorSubtype == UAC_MS_GENERAL)
+			return ms_ep;
+		extralen -= length;
+		extra += length;
+	}
+	return NULL;
+}
+
+/*
+ * Returns MIDIStreaming device capabilities.
+ */
+static int snd_usbmidi_get_ms_info(struct snd_usb_midi *umidi,
+				   struct snd_usb_midi_endpoint_info *endpoints)
+{
+	struct usb_interface *intf;
+	struct usb_host_interface *hostif;
+	struct usb_interface_descriptor *intfd;
+	struct usb_ms_header_descriptor *ms_header;
+	struct usb_host_endpoint *hostep;
+	struct usb_endpoint_descriptor *ep;
+	struct usb_ms_endpoint_descriptor *ms_ep;
+	int i, j, epidx;
+
+	intf = umidi->iface;
+	if (!intf)
+		return -ENXIO;
+	hostif = &intf->altsetting[0];
+	intfd = get_iface_desc(hostif);
+	ms_header = (struct usb_ms_header_descriptor *)hostif->extra;
+	if (hostif->extralen >= 7 &&
+	    ms_header->bLength >= 7 &&
+	    ms_header->bDescriptorType == USB_DT_CS_INTERFACE &&
+	    ms_header->bDescriptorSubtype == UAC_HEADER)
+		dev_dbg(&umidi->dev->dev, "MIDIStreaming version %02x.%02x\n",
+			    ((uint8_t *)&ms_header->bcdMSC)[1], ((uint8_t *)&ms_header->bcdMSC)[0]);
+	else
+		dev_warn(&umidi->dev->dev,
+			 "MIDIStreaming interface descriptor not found\n");
+
+	epidx = 0;
+	for (i = 0; i < intfd->bNumEndpoints; ++i) {
+		hostep = &hostif->endpoint[i];
+		ep = get_ep_desc(hostep);
+		if (!usb_endpoint_xfer_bulk(ep) && !usb_endpoint_xfer_int(ep))
+			continue;
+		ms_ep = find_usb_ms_endpoint_descriptor(hostep);
+		if (!ms_ep)
+			continue;
+		if (ms_ep->bLength <= sizeof(*ms_ep))
+			continue;
+		if (ms_ep->bNumEmbMIDIJack > 0x10)
+			continue;
+		if (ms_ep->bLength < sizeof(*ms_ep) + ms_ep->bNumEmbMIDIJack)
+			continue;
+		if (usb_endpoint_dir_out(ep)) {
+			if (endpoints[epidx].out_ep) {
+				if (++epidx >= MIDI_MAX_ENDPOINTS) {
+					dev_warn(&umidi->dev->dev,
+						 "too many endpoints\n");
+					break;
+				}
+			}
+			endpoints[epidx].out_ep = usb_endpoint_num(ep);
+			if (usb_endpoint_xfer_int(ep))
+				endpoints[epidx].out_interval = ep->bInterval;
+			else if (snd_usb_get_speed(umidi->dev) == USB_SPEED_LOW)
+				/*
+				 * Low speed bulk transfers don't exist, so
+				 * force interrupt transfers for devices like
+				 * ESI MIDI Mate that try to use them anyway.
+				 */
+				endpoints[epidx].out_interval = 1;
+			endpoints[epidx].out_cables =
+				(1 << ms_ep->bNumEmbMIDIJack) - 1;
+			for (j = 0; j < ms_ep->bNumEmbMIDIJack; ++j)
+				endpoints[epidx].assoc_out_jacks[j] = ms_ep->baAssocJackID[j];
+			for (; j < ARRAY_SIZE(endpoints[epidx].assoc_out_jacks); ++j)
+				endpoints[epidx].assoc_out_jacks[j] = -1;
+			dev_dbg(&umidi->dev->dev, "EP %02X: %d jack(s)\n",
+				ep->bEndpointAddress, ms_ep->bNumEmbMIDIJack);
+		} else {
+			if (endpoints[epidx].in_ep) {
+				if (++epidx >= MIDI_MAX_ENDPOINTS) {
+					dev_warn(&umidi->dev->dev,
+						 "too many endpoints\n");
+					break;
+				}
+			}
+			endpoints[epidx].in_ep = usb_endpoint_num(ep);
+			if (usb_endpoint_xfer_int(ep))
+				endpoints[epidx].in_interval = ep->bInterval;
+			else if (snd_usb_get_speed(umidi->dev) == USB_SPEED_LOW)
+				endpoints[epidx].in_interval = 1;
+			endpoints[epidx].in_cables =
+				(1 << ms_ep->bNumEmbMIDIJack) - 1;
+			for (j = 0; j < ms_ep->bNumEmbMIDIJack; ++j)
+				endpoints[epidx].assoc_in_jacks[j] = ms_ep->baAssocJackID[j];
+			for (; j < ARRAY_SIZE(endpoints[epidx].assoc_in_jacks); ++j)
+				endpoints[epidx].assoc_in_jacks[j] = -1;
+			dev_dbg(&umidi->dev->dev, "EP %02X: %d jack(s)\n",
+				ep->bEndpointAddress, ms_ep->bNumEmbMIDIJack);
+		}
+	}
+	return 0;
+}
+
+static int roland_load_info(struct snd_kcontrol *kcontrol,
+			    struct snd_ctl_elem_info *info)
+{
+	static const char *const names[] = { "High Load", "Light Load" };
+
+	return snd_ctl_enum_info(info, 1, 2, names);
+}
+
+static int roland_load_get(struct snd_kcontrol *kcontrol,
+			   struct snd_ctl_elem_value *value)
+{
+	value->value.enumerated.item[0] = kcontrol->private_value;
+	return 0;
+}
+
+static int roland_load_put(struct snd_kcontrol *kcontrol,
+			   struct snd_ctl_elem_value *value)
+{
+	struct snd_usb_midi *umidi = snd_kcontrol_chip(kcontrol);
+	int changed;
+
+	if (value->value.enumerated.item[0] > 1)
+		return -EINVAL;
+	guard(mutex)(&umidi->mutex);
+	changed = value->value.enumerated.item[0] != kcontrol->private_value;
+	if (changed)
+		kcontrol->private_value = value->value.enumerated.item[0];
+	return changed;
+}
+
+static const struct snd_kcontrol_new roland_load_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "MIDI Input Mode",
+	.info = roland_load_info,
+	.get = roland_load_get,
+	.put = roland_load_put,
+	.private_value = 1,
+};
+
+/*
+ * On Roland devices, use the second alternate setting to be able to use
+ * the interrupt input endpoint.
+ */
+static void snd_usbmidi_switch_roland_altsetting(struct snd_usb_midi *umidi)
+{
+	struct usb_interface *intf;
+	struct usb_host_interface *hostif;
+	struct usb_interface_descriptor *intfd;
+
+	intf = umidi->iface;
+	if (!intf || intf->num_altsetting != 2)
+		return;
+
+	hostif = &intf->altsetting[1];
+	intfd = get_iface_desc(hostif);
+       /* If either or both of the endpoints support interrupt transfer,
+        * then use the alternate setting
+        */
+	if (intfd->bNumEndpoints != 2 ||
+	    !((get_endpoint(hostif, 0)->bmAttributes &
+	       USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT ||
+	      (get_endpoint(hostif, 1)->bmAttributes &
+	       USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT))
+		return;
+
+	dev_dbg(&umidi->dev->dev, "switching to altsetting %d with int ep\n",
+		    intfd->bAlternateSetting);
+	usb_set_interface(umidi->dev, intfd->bInterfaceNumber,
+			  intfd->bAlternateSetting);
+
+	umidi->roland_load_ctl = snd_ctl_new1(&roland_load_ctl, umidi);
+	if (snd_ctl_add(umidi->card, umidi->roland_load_ctl) < 0)
+		umidi->roland_load_ctl = NULL;
+}
+
+/*
+ * Try to find any usable endpoints in the interface.
+ */
+static int snd_usbmidi_detect_endpoints(struct snd_usb_midi *umidi,
+					struct snd_usb_midi_endpoint_info *endpoint,
+					int max_endpoints)
+{
+	struct usb_interface *intf;
+	struct usb_host_interface *hostif;
+	struct usb_interface_descriptor *intfd;
+	struct usb_endpoint_descriptor *epd;
+	int i, out_eps = 0, in_eps = 0;
+
+	if (USB_ID_VENDOR(umidi->usb_id) == 0x0582)
+		snd_usbmidi_switch_roland_altsetting(umidi);
+
+	if (endpoint[0].out_ep || endpoint[0].in_ep)
+		return 0;
+
+	intf = umidi->iface;
+	if (!intf || intf->num_altsetting < 1)
+		return -ENOENT;
+	hostif = intf->cur_altsetting;
+	intfd = get_iface_desc(hostif);
+
+	for (i = 0; i < intfd->bNumEndpoints; ++i) {
+		epd = get_endpoint(hostif, i);
+		if (!usb_endpoint_xfer_bulk(epd) &&
+		    !usb_endpoint_xfer_int(epd))
+			continue;
+		if (out_eps < max_endpoints &&
+		    usb_endpoint_dir_out(epd)) {
+			endpoint[out_eps].out_ep = usb_endpoint_num(epd);
+			if (usb_endpoint_xfer_int(epd))
+				endpoint[out_eps].out_interval = epd->bInterval;
+			++out_eps;
+		}
+		if (in_eps < max_endpoints &&
+		    usb_endpoint_dir_in(epd)) {
+			endpoint[in_eps].in_ep = usb_endpoint_num(epd);
+			if (usb_endpoint_xfer_int(epd))
+				endpoint[in_eps].in_interval = epd->bInterval;
+			++in_eps;
+		}
+	}
+	return (out_eps || in_eps) ? 0 : -ENOENT;
+}
+
+/*
+ * Detects the endpoints for one-port-per-endpoint protocols.
+ */
+static int snd_usbmidi_detect_per_port_endpoints(struct snd_usb_midi *umidi,
+						 struct snd_usb_midi_endpoint_info *endpoints)
+{
+	int err, i;
+
+	err = snd_usbmidi_detect_endpoints(umidi, endpoints, MIDI_MAX_ENDPOINTS);
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
+		if (endpoints[i].out_ep)
+			endpoints[i].out_cables = 0x0001;
+		if (endpoints[i].in_ep)
+			endpoints[i].in_cables = 0x0001;
+	}
+	return err;
+}
+
+/*
+ * Detects the endpoints and ports of Yamaha devices.
+ */
+static int snd_usbmidi_detect_yamaha(struct snd_usb_midi *umidi,
+				     struct snd_usb_midi_endpoint_info *endpoint)
+{
+	struct usb_interface *intf;
+	struct usb_host_interface *hostif;
+	struct usb_interface_descriptor *intfd;
+	uint8_t *cs_desc;
+
+	intf = umidi->iface;
+	if (!intf)
+		return -ENOENT;
+	hostif = intf->altsetting;
+	intfd = get_iface_desc(hostif);
+	if (intfd->bNumEndpoints < 1)
+		return -ENOENT;
+
+	/*
+	 * For each port there is one MIDI_IN/OUT_JACK descriptor, not
+	 * necessarily with any useful contents.  So simply count 'em.
+	 */
+	for (cs_desc = hostif->extra;
+	     cs_desc < hostif->extra + hostif->extralen && cs_desc[0] >= 2;
+	     cs_desc += cs_desc[0]) {
+		if (cs_desc[1] == USB_DT_CS_INTERFACE) {
+			if (cs_desc[2] == UAC_MIDI_IN_JACK)
+				endpoint->in_cables =
+					(endpoint->in_cables << 1) | 1;
+			else if (cs_desc[2] == UAC_MIDI_OUT_JACK)
+				endpoint->out_cables =
+					(endpoint->out_cables << 1) | 1;
+		}
+	}
+	if (!endpoint->in_cables && !endpoint->out_cables)
+		return -ENOENT;
+
+	return snd_usbmidi_detect_endpoints(umidi, endpoint, 1);
+}
+
+/*
+ * Detects the endpoints and ports of Roland devices.
+ */
+static int snd_usbmidi_detect_roland(struct snd_usb_midi *umidi,
+				     struct snd_usb_midi_endpoint_info *endpoint)
+{
+	struct usb_interface *intf;
+	struct usb_host_interface *hostif;
+	u8 *cs_desc;
+
+	intf = umidi->iface;
+	if (!intf)
+		return -ENOENT;
+	hostif = intf->altsetting;
+	/*
+	 * Some devices have a descriptor <06 24 F1 02 <inputs> <outputs>>,
+	 * some have standard class descriptors, or both kinds, or neither.
+	 */
+	for (cs_desc = hostif->extra;
+	     cs_desc < hostif->extra + hostif->extralen && cs_desc[0] >= 2;
+	     cs_desc += cs_desc[0]) {
+		if (cs_desc[0] >= 6 &&
+		    cs_desc[1] == USB_DT_CS_INTERFACE &&
+		    cs_desc[2] == 0xf1 &&
+		    cs_desc[3] == 0x02) {
+			if (cs_desc[4] > 0x10 || cs_desc[5] > 0x10)
+				continue;
+			endpoint->in_cables  = (1 << cs_desc[4]) - 1;
+			endpoint->out_cables = (1 << cs_desc[5]) - 1;
+			return snd_usbmidi_detect_endpoints(umidi, endpoint, 1);
+		} else if (cs_desc[0] >= 7 &&
+			   cs_desc[1] == USB_DT_CS_INTERFACE &&
+			   cs_desc[2] == UAC_HEADER) {
+			return snd_usbmidi_get_ms_info(umidi, endpoint);
+		}
+	}
+
+	return -ENODEV;
+}
+
+/*
+ * Creates the endpoints and their ports for Midiman devices.
+ */
+static int snd_usbmidi_create_endpoints_midiman(struct snd_usb_midi *umidi,
+						struct snd_usb_midi_endpoint_info *endpoint)
+{
+	struct snd_usb_midi_endpoint_info ep_info;
+	struct usb_interface *intf;
+	struct usb_host_interface *hostif;
+	struct usb_interface_descriptor *intfd;
+	struct usb_endpoint_descriptor *epd;
+	int cable, err;
+
+	intf = umidi->iface;
+	if (!intf)
+		return -ENOENT;
+	hostif = intf->altsetting;
+	intfd = get_iface_desc(hostif);
+	/*
+	 * The various MidiSport devices have more or less random endpoint
+	 * numbers, so we have to identify the endpoints by their index in
+	 * the descriptor array, like the driver for that other OS does.
+	 *
+	 * There is one interrupt input endpoint for all input ports, one
+	 * bulk output endpoint for even-numbered ports, and one for odd-
+	 * numbered ports.  Both bulk output endpoints have corresponding
+	 * input bulk endpoints (at indices 1 and 3) which aren't used.
+	 */
+	if (intfd->bNumEndpoints < (endpoint->out_cables > 0x0001 ? 5 : 3)) {
+		dev_dbg(&umidi->dev->dev, "not enough endpoints\n");
+		return -ENOENT;
+	}
+
+	epd = get_endpoint(hostif, 0);
+	if (!usb_endpoint_dir_in(epd) || !usb_endpoint_xfer_int(epd)) {
+		dev_dbg(&umidi->dev->dev, "endpoint[0] isn't interrupt\n");
+		return -ENXIO;
+	}
+	epd = get_endpoint(hostif, 2);
+	if (!usb_endpoint_dir_out(epd) || !usb_endpoint_xfer_bulk(epd)) {
+		dev_dbg(&umidi->dev->dev, "endpoint[2] isn't bulk output\n");
+		return -ENXIO;
+	}
+	if (endpoint->out_cables > 0x0001) {
+		epd = get_endpoint(hostif, 4);
+		if (!usb_endpoint_dir_out(epd) ||
+		    !usb_endpoint_xfer_bulk(epd)) {
+			dev_dbg(&umidi->dev->dev,
+				"endpoint[4] isn't bulk output\n");
+			return -ENXIO;
+		}
+	}
+
+	ep_info.out_ep = get_endpoint(hostif, 2)->bEndpointAddress &
+		USB_ENDPOINT_NUMBER_MASK;
+	ep_info.out_interval = 0;
+	ep_info.out_cables = endpoint->out_cables & 0x5555;
+	err = snd_usbmidi_out_endpoint_create(umidi, &ep_info,
+					      &umidi->endpoints[0]);
+	if (err < 0)
+		return err;
+
+	ep_info.in_ep = get_endpoint(hostif, 0)->bEndpointAddress &
+		USB_ENDPOINT_NUMBER_MASK;
+	ep_info.in_interval = get_endpoint(hostif, 0)->bInterval;
+	ep_info.in_cables = endpoint->in_cables;
+	err = snd_usbmidi_in_endpoint_create(umidi, &ep_info,
+					     &umidi->endpoints[0]);
+	if (err < 0)
+		return err;
+
+	if (endpoint->out_cables > 0x0001) {
+		ep_info.out_ep = get_endpoint(hostif, 4)->bEndpointAddress &
+			USB_ENDPOINT_NUMBER_MASK;
+		ep_info.out_cables = endpoint->out_cables & 0xaaaa;
+		err = snd_usbmidi_out_endpoint_create(umidi, &ep_info,
+						      &umidi->endpoints[1]);
+		if (err < 0)
+			return err;
+	}
+
+	for (cable = 0; cable < 0x10; ++cable) {
+		if (endpoint->out_cables & (1 << cable))
+			snd_usbmidi_init_substream(umidi,
+						   SNDRV_RAWMIDI_STREAM_OUTPUT,
+						   cable,
+						   -1 /* prevent trying to find jack */,
+						   &umidi->endpoints[cable & 1].out->ports[cable].substream);
+		if (endpoint->in_cables & (1 << cable))
+			snd_usbmidi_init_substream(umidi,
+						   SNDRV_RAWMIDI_STREAM_INPUT,
+						   cable,
+						   -1 /* prevent trying to find jack */,
+						   &umidi->endpoints[0].in->ports[cable].substream);
+	}
+	return 0;
+}
+
+static const struct snd_rawmidi_global_ops snd_usbmidi_ops = {
+	.get_port_info = snd_usbmidi_get_port_info,
+};
+
+static int snd_usbmidi_create_rawmidi(struct snd_usb_midi *umidi,
+				      int out_ports, int in_ports)
+{
+	struct snd_rawmidi *rmidi;
+	int err;
+
+	err = snd_rawmidi_new(umidi->card, "USB MIDI",
+			      umidi->next_midi_device++,
+			      out_ports, in_ports, &rmidi);
+	if (err < 0)
+		return err;
+	strscpy(rmidi->name, umidi->card->shortname);
+	rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
+			    SNDRV_RAWMIDI_INFO_INPUT |
+			    SNDRV_RAWMIDI_INFO_DUPLEX;
+	rmidi->ops = &snd_usbmidi_ops;
+	rmidi->private_data = umidi;
+	rmidi->private_free = snd_usbmidi_rawmidi_free;
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+			    &snd_usbmidi_output_ops);
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+			    &snd_usbmidi_input_ops);
+
+	umidi->rmidi = rmidi;
+	return 0;
+}
+
+/*
+ * Temporarily stop input.
+ */
+void snd_usbmidi_input_stop(struct list_head *p)
+{
+	struct snd_usb_midi *umidi;
+	unsigned int i, j;
+
+	umidi = list_entry(p, struct snd_usb_midi, list);
+	if (!umidi->input_running)
+		return;
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
+		struct snd_usb_midi_endpoint *ep = &umidi->endpoints[i];
+		if (ep->in)
+			for (j = 0; j < INPUT_URBS; ++j)
+				usb_kill_urb(ep->in->urbs[j]);
+	}
+	umidi->input_running = 0;
+}
+EXPORT_SYMBOL(snd_usbmidi_input_stop);
+
+static void snd_usbmidi_input_start_ep(struct snd_usb_midi *umidi,
+				       struct snd_usb_midi_in_endpoint *ep)
+{
+	unsigned int i;
+
+	if (!ep)
+		return;
+	for (i = 0; i < INPUT_URBS; ++i) {
+		struct urb *urb = ep->urbs[i];
+		scoped_guard(spinlock_irqsave, &umidi->disc_lock) {
+			if (!atomic_read(&urb->use_count)) {
+				urb->dev = ep->umidi->dev;
+				snd_usbmidi_submit_urb(urb, GFP_ATOMIC);
+			}
+		}
+	}
+}
+
+/*
+ * Resume input after a call to snd_usbmidi_input_stop().
+ */
+void snd_usbmidi_input_start(struct list_head *p)
+{
+	struct snd_usb_midi *umidi;
+	int i;
+
+	umidi = list_entry(p, struct snd_usb_midi, list);
+	if (umidi->input_running || !umidi->opened[1])
+		return;
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i)
+		snd_usbmidi_input_start_ep(umidi, umidi->endpoints[i].in);
+	umidi->input_running = 1;
+}
+EXPORT_SYMBOL(snd_usbmidi_input_start);
+
+/*
+ * Prepare for suspend. Typically called from the USB suspend callback.
+ */
+void snd_usbmidi_suspend(struct list_head *p)
+{
+	struct snd_usb_midi *umidi;
+
+	umidi = list_entry(p, struct snd_usb_midi, list);
+	guard(mutex)(&umidi->mutex);
+	snd_usbmidi_input_stop(p);
+}
+EXPORT_SYMBOL(snd_usbmidi_suspend);
+
+/*
+ * Resume. Typically called from the USB resume callback.
+ */
+void snd_usbmidi_resume(struct list_head *p)
+{
+	struct snd_usb_midi *umidi;
+
+	umidi = list_entry(p, struct snd_usb_midi, list);
+	guard(mutex)(&umidi->mutex);
+	snd_usbmidi_input_start(p);
+}
+EXPORT_SYMBOL(snd_usbmidi_resume);
+
+/*
+ * Creates and registers everything needed for a MIDI streaming interface.
+ */
+int __snd_usbmidi_create(struct snd_card *card,
+			 struct usb_interface *iface,
+			 struct list_head *midi_list,
+			 const struct snd_usb_audio_quirk *quirk,
+			 unsigned int usb_id,
+			 unsigned int *num_rawmidis)
+{
+	struct snd_usb_midi *umidi;
+	struct snd_usb_midi_endpoint_info endpoints[MIDI_MAX_ENDPOINTS];
+	int out_ports, in_ports;
+	int i, err;
+
+	umidi = kzalloc_obj(*umidi);
+	if (!umidi)
+		return -ENOMEM;
+	umidi->dev = interface_to_usbdev(iface);
+	umidi->card = card;
+	umidi->iface = iface;
+	umidi->quirk = quirk;
+	umidi->usb_protocol_ops = &snd_usbmidi_standard_ops;
+	if (num_rawmidis)
+		umidi->next_midi_device = *num_rawmidis;
+	spin_lock_init(&umidi->disc_lock);
+	init_rwsem(&umidi->disc_rwsem);
+	mutex_init(&umidi->mutex);
+	if (!usb_id)
+		usb_id = USB_ID(le16_to_cpu(umidi->dev->descriptor.idVendor),
+			       le16_to_cpu(umidi->dev->descriptor.idProduct));
+	umidi->usb_id = usb_id;
+	timer_setup(&umidi->error_timer, snd_usbmidi_error_timer, 0);
+
+	/* detect the endpoint(s) to use */
+	memset(endpoints, 0, sizeof(endpoints));
+	switch (quirk ? quirk->type : QUIRK_MIDI_STANDARD_INTERFACE) {
+	case QUIRK_MIDI_STANDARD_INTERFACE:
+		err = snd_usbmidi_get_ms_info(umidi, endpoints);
+		if (umidi->usb_id == USB_ID(0x0763, 0x0150)) /* M-Audio Uno */
+			umidi->usb_protocol_ops =
+				&snd_usbmidi_maudio_broken_running_status_ops;
+		break;
+	case QUIRK_MIDI_US122L:
+		umidi->usb_protocol_ops = &snd_usbmidi_122l_ops;
+		fallthrough;
+	case QUIRK_MIDI_FIXED_ENDPOINT:
+		memcpy(&endpoints[0], quirk->data,
+		       sizeof(struct snd_usb_midi_endpoint_info));
+		err = snd_usbmidi_detect_endpoints(umidi, &endpoints[0], 1);
+		break;
+	case QUIRK_MIDI_YAMAHA:
+		err = snd_usbmidi_detect_yamaha(umidi, &endpoints[0]);
+		break;
+	case QUIRK_MIDI_ROLAND:
+		err = snd_usbmidi_detect_roland(umidi, &endpoints[0]);
+		break;
+	case QUIRK_MIDI_MIDIMAN:
+		umidi->usb_protocol_ops = &snd_usbmidi_midiman_ops;
+		memcpy(&endpoints[0], quirk->data,
+		       sizeof(struct snd_usb_midi_endpoint_info));
+		err = 0;
+		break;
+	case QUIRK_MIDI_NOVATION:
+		umidi->usb_protocol_ops = &snd_usbmidi_novation_ops;
+		err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+		break;
+	case QUIRK_MIDI_RAW_BYTES:
+		umidi->usb_protocol_ops = &snd_usbmidi_raw_ops;
+		/*
+		 * Interface 1 contains isochronous endpoints, but with the same
+		 * numbers as in interface 0.  Since it is interface 1 that the
+		 * USB core has most recently seen, these descriptors are now
+		 * associated with the endpoint numbers.  This will foul up our
+		 * attempts to submit bulk/interrupt URBs to the endpoints in
+		 * interface 0, so we have to make sure that the USB core looks
+		 * again at interface 0 by calling usb_set_interface() on it.
+		 */
+		if (umidi->usb_id == USB_ID(0x07fd, 0x0001)) /* MOTU Fastlane */
+			usb_set_interface(umidi->dev, 0, 0);
+		err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+		break;
+	case QUIRK_MIDI_EMAGIC:
+		umidi->usb_protocol_ops = &snd_usbmidi_emagic_ops;
+		memcpy(&endpoints[0], quirk->data,
+		       sizeof(struct snd_usb_midi_endpoint_info));
+		err = snd_usbmidi_detect_endpoints(umidi, &endpoints[0], 1);
+		break;
+	case QUIRK_MIDI_CME:
+		umidi->usb_protocol_ops = &snd_usbmidi_cme_ops;
+		err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+		break;
+	case QUIRK_MIDI_AKAI:
+		umidi->usb_protocol_ops = &snd_usbmidi_akai_ops;
+		err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+		/* endpoint 1 is input-only */
+		endpoints[1].out_cables = 0;
+		break;
+	case QUIRK_MIDI_FTDI:
+		umidi->usb_protocol_ops = &snd_usbmidi_ftdi_ops;
+
+		/* set baud rate to 31250 (48 MHz / 16 / 96) */
+		err = usb_control_msg(umidi->dev, usb_sndctrlpipe(umidi->dev, 0),
+				      3, 0x40, 0x60, 0, NULL, 0, 1000);
+		if (err < 0)
+			break;
+
+		err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+		break;
+	case QUIRK_MIDI_CH345:
+		umidi->usb_protocol_ops = &snd_usbmidi_ch345_broken_sysex_ops;
+		err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+		break;
+	default:
+		dev_err(&umidi->dev->dev, "invalid quirk type %d\n",
+			quirk->type);
+		err = -ENXIO;
+		break;
+	}
+	if (err < 0)
+		goto free_midi;
+
+	/* create rawmidi device */
+	out_ports = 0;
+	in_ports = 0;
+	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
+		out_ports += hweight16(endpoints[i].out_cables);
+		in_ports += hweight16(endpoints[i].in_cables);
+	}
+	err = snd_usbmidi_create_rawmidi(umidi, out_ports, in_ports);
+	if (err < 0)
+		goto free_midi;
+
+	/* create endpoint/port structures */
+	if (quirk && quirk->type == QUIRK_MIDI_MIDIMAN)
+		err = snd_usbmidi_create_endpoints_midiman(umidi, &endpoints[0]);
+	else
+		err = snd_usbmidi_create_endpoints(umidi, endpoints);
+	if (err < 0)
+		goto exit;
+
+	usb_autopm_get_interface_no_resume(umidi->iface);
+
+	list_add_tail(&umidi->list, midi_list);
+	if (num_rawmidis)
+		*num_rawmidis = umidi->next_midi_device;
+	return 0;
+
+free_midi:
+	kfree(umidi);
+exit:
+	return err;
+}
+EXPORT_SYMBOL(__snd_usbmidi_create);
diff --git a/sound/usb/midi.h b/sound/usb/midi.h
new file mode 100644
index 000000000..2100f1486
--- /dev/null
+++ b/sound/usb/midi.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBMIDI_H
+#define __USBMIDI_H
+
+/* maximum number of endpoints per interface */
+#define MIDI_MAX_ENDPOINTS 2
+
+/* data for QUIRK_MIDI_FIXED_ENDPOINT */
+struct snd_usb_midi_endpoint_info {
+	int8_t   out_ep;	/* ep number, 0 autodetect */
+	uint8_t  out_interval;	/* interval for interrupt endpoints */
+	int8_t   in_ep;
+	uint8_t  in_interval;
+	uint16_t out_cables;	/* bitmask */
+	uint16_t in_cables;	/* bitmask */
+	int16_t  assoc_in_jacks[16];
+	int16_t  assoc_out_jacks[16];
+};
+
+/* for QUIRK_MIDI_YAMAHA, data is NULL */
+
+/* for QUIRK_MIDI_MIDIMAN, data points to a snd_usb_midi_endpoint_info
+ * structure (out_cables and in_cables only) */
+
+/* for QUIRK_COMPOSITE, data points to an array of snd_usb_audio_quirk
+ * structures, terminated with .ifnum = -1 */
+
+/* for QUIRK_AUDIO_FIXED_ENDPOINT, data points to an audioformat structure */
+
+/* for QUIRK_AUDIO/MIDI_STANDARD_INTERFACE, data is NULL */
+
+/* for QUIRK_AUDIO_EDIROL_UA700_UA25/UA1000, data is NULL */
+
+/* for QUIRK_IGNORE_INTERFACE, data is NULL */
+
+/* for QUIRK_MIDI_NOVATION and _RAW, data is NULL */
+
+/* for QUIRK_MIDI_EMAGIC, data points to a snd_usb_midi_endpoint_info
+ * structure (out_cables and in_cables only) */
+
+/* for QUIRK_MIDI_CME, data is NULL */
+
+/* for QUIRK_MIDI_AKAI, data is NULL */
+
+int __snd_usbmidi_create(struct snd_card *card,
+			 struct usb_interface *iface,
+			 struct list_head *midi_list,
+			 const struct snd_usb_audio_quirk *quirk,
+			 unsigned int usb_id,
+			 unsigned int *num_rawmidis);
+
+static inline int snd_usbmidi_create(struct snd_card *card,
+		       struct usb_interface *iface,
+		       struct list_head *midi_list,
+		       const struct snd_usb_audio_quirk *quirk)
+{
+	return __snd_usbmidi_create(card, iface, midi_list, quirk, 0, NULL);
+}
+
+void snd_usbmidi_input_stop(struct list_head *p);
+void snd_usbmidi_input_start(struct list_head *p);
+void snd_usbmidi_disconnect(struct list_head *p);
+void snd_usbmidi_suspend(struct list_head *p);
+void snd_usbmidi_resume(struct list_head *p);
+
+#endif /* __USBMIDI_H */
diff --git a/sound/usb/midi2.c b/sound/usb/midi2.c
new file mode 100644
index 000000000..1dc78f536
--- /dev/null
+++ b/sound/usb/midi2.c
@@ -0,0 +1,1250 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MIDI 2.0 support
+ */
+
+#include <linux/bitops.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/midi.h>
+#include <linux/usb/midi-v2.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/ump.h>
+#include "usbaudio.h"
+#include "midi.h"
+#include "midi2.h"
+#include "helper.h"
+
+static bool midi2_enable = true;
+module_param(midi2_enable, bool, 0444);
+MODULE_PARM_DESC(midi2_enable, "Enable MIDI 2.0 support.");
+
+static bool midi2_ump_probe = true;
+module_param(midi2_ump_probe, bool, 0444);
+MODULE_PARM_DESC(midi2_ump_probe, "Probe UMP v1.1 support at first.");
+
+/* stream direction; just shorter names */
+enum {
+	STR_OUT = SNDRV_RAWMIDI_STREAM_OUTPUT,
+	STR_IN = SNDRV_RAWMIDI_STREAM_INPUT
+};
+
+#define NUM_URBS	8
+
+struct snd_usb_midi2_urb;
+struct snd_usb_midi2_endpoint;
+struct snd_usb_midi2_ump;
+struct snd_usb_midi2_interface;
+
+/* URB context */
+struct snd_usb_midi2_urb {
+	struct urb *urb;
+	struct snd_usb_midi2_endpoint *ep;
+	unsigned int index;		/* array index */
+};
+
+/* A USB MIDI input/output endpoint */
+struct snd_usb_midi2_endpoint {
+	struct usb_device *dev;
+	const struct usb_ms20_endpoint_descriptor *ms_ep; /* reference to EP descriptor */
+	struct snd_usb_midi2_endpoint *pair;	/* bidirectional pair EP */
+	struct snd_usb_midi2_ump *rmidi;	/* assigned UMP EP pair */
+	struct snd_ump_endpoint *ump;		/* assigned UMP EP */
+	int direction;			/* direction (STR_IN/OUT) */
+	unsigned int endpoint;		/* EP number */
+	unsigned int pipe;		/* URB pipe */
+	unsigned int packets;		/* packet buffer size in bytes */
+	unsigned int interval;		/* interval for INT EP */
+	wait_queue_head_t wait;		/* URB waiter */
+	spinlock_t lock;		/* URB locking */
+	struct snd_rawmidi_substream *substream; /* NULL when closed */
+	unsigned int num_urbs;		/* number of allocated URBs */
+	unsigned long urb_free;		/* bitmap for free URBs */
+	unsigned long urb_free_mask;	/* bitmask for free URBs */
+	atomic_t running;		/* running status */
+	atomic_t suspended;		/* saved running status for suspend */
+	bool disconnected;		/* shadow of umidi->disconnected */
+	struct list_head list;		/* list to umidi->ep_list */
+	struct snd_usb_midi2_urb urbs[NUM_URBS];
+};
+
+/* A UMP endpoint - one or two USB MIDI endpoints are assigned */
+struct snd_usb_midi2_ump {
+	struct usb_device *dev;
+	struct snd_usb_midi2_interface *umidi;	/* reference to MIDI iface */
+	struct snd_ump_endpoint *ump;		/* assigned UMP EP object */
+	struct snd_usb_midi2_endpoint *eps[2];	/* USB MIDI endpoints */
+	int index;				/* rawmidi device index */
+	unsigned char usb_block_id;		/* USB GTB id used for finding a pair */
+	bool ump_parsed;			/* Parsed UMP 1.1 EP/FB info*/
+	struct list_head list;		/* list to umidi->rawmidi_list */
+};
+
+/* top-level instance per USB MIDI interface */
+struct snd_usb_midi2_interface {
+	struct snd_usb_audio *chip;	/* assigned USB-audio card */
+	struct usb_interface *iface;	/* assigned USB interface */
+	struct usb_host_interface *hostif;
+	const char *blk_descs;		/* group terminal block descriptors */
+	unsigned int blk_desc_size;	/* size of GTB descriptors */
+	bool disconnected;
+	struct list_head ep_list;	/* list of endpoints */
+	struct list_head rawmidi_list;	/* list of UMP rawmidis */
+	struct list_head list;		/* list to chip->midi_v2_list */
+};
+
+/* submit URBs as much as possible; used for both input and output */
+static void do_submit_urbs_locked(struct snd_usb_midi2_endpoint *ep,
+				  int (*prepare)(struct snd_usb_midi2_endpoint *,
+						 struct urb *))
+{
+	struct snd_usb_midi2_urb *ctx;
+	int index, err = 0;
+
+	if (ep->disconnected)
+		return;
+
+	while (ep->urb_free) {
+		index = find_first_bit(&ep->urb_free, ep->num_urbs);
+		if (index >= ep->num_urbs)
+			return;
+		ctx = &ep->urbs[index];
+		err = prepare(ep, ctx->urb);
+		if (err < 0)
+			return;
+		if (!ctx->urb->transfer_buffer_length)
+			return;
+		ctx->urb->dev = ep->dev;
+		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
+		if (err < 0) {
+			dev_dbg(&ep->dev->dev,
+				"usb_submit_urb error %d\n", err);
+			return;
+		}
+		clear_bit(index, &ep->urb_free);
+	}
+}
+
+/* prepare for output submission: copy from rawmidi buffer to urb packet */
+static int prepare_output_urb(struct snd_usb_midi2_endpoint *ep,
+			      struct urb *urb)
+{
+	int count;
+
+	count = snd_ump_transmit(ep->ump, urb->transfer_buffer,
+				 ep->packets);
+	if (count < 0) {
+		dev_dbg(&ep->dev->dev, "rawmidi transmit error %d\n", count);
+		return count;
+	}
+	cpu_to_le32_array((u32 *)urb->transfer_buffer, count >> 2);
+	urb->transfer_buffer_length = count;
+	return 0;
+}
+
+static void submit_output_urbs_locked(struct snd_usb_midi2_endpoint *ep)
+{
+	do_submit_urbs_locked(ep, prepare_output_urb);
+}
+
+/* URB completion for output; re-filling and re-submit */
+static void output_urb_complete(struct urb *urb)
+{
+	struct snd_usb_midi2_urb *ctx = urb->context;
+	struct snd_usb_midi2_endpoint *ep = ctx->ep;
+
+	guard(spinlock_irqsave)(&ep->lock);
+	set_bit(ctx->index, &ep->urb_free);
+	if (urb->status >= 0 && atomic_read(&ep->running))
+		submit_output_urbs_locked(ep);
+	if (ep->urb_free == ep->urb_free_mask)
+		wake_up(&ep->wait);
+}
+
+/* prepare for input submission: just set the buffer length */
+static int prepare_input_urb(struct snd_usb_midi2_endpoint *ep,
+			     struct urb *urb)
+{
+	urb->transfer_buffer_length = ep->packets;
+	return 0;
+}
+
+static void submit_input_urbs_locked(struct snd_usb_midi2_endpoint *ep)
+{
+	do_submit_urbs_locked(ep, prepare_input_urb);
+}
+
+/* URB completion for input; copy into rawmidi buffer and resubmit */
+static void input_urb_complete(struct urb *urb)
+{
+	struct snd_usb_midi2_urb *ctx = urb->context;
+	struct snd_usb_midi2_endpoint *ep = ctx->ep;
+	int len;
+
+	guard(spinlock_irqsave)(&ep->lock);
+	if (ep->disconnected || urb->status < 0)
+		goto dequeue;
+	len = urb->actual_length;
+	len &= ~3; /* align UMP */
+	if (len > ep->packets)
+		len = ep->packets;
+	if (len > 0) {
+		le32_to_cpu_array((u32 *)urb->transfer_buffer, len >> 2);
+		snd_ump_receive(ep->ump, (u32 *)urb->transfer_buffer, len);
+	}
+ dequeue:
+	set_bit(ctx->index, &ep->urb_free);
+	submit_input_urbs_locked(ep);
+	if (ep->urb_free == ep->urb_free_mask)
+		wake_up(&ep->wait);
+}
+
+/* URB submission helper; for both direction */
+static void submit_io_urbs(struct snd_usb_midi2_endpoint *ep)
+{
+	if (!ep)
+		return;
+	guard(spinlock_irqsave)(&ep->lock);
+	if (ep->direction == STR_IN)
+		submit_input_urbs_locked(ep);
+	else
+		submit_output_urbs_locked(ep);
+}
+
+/* kill URBs for close, suspend and disconnect */
+static void kill_midi_urbs(struct snd_usb_midi2_endpoint *ep, bool suspending)
+{
+	int i;
+
+	if (!ep)
+		return;
+	if (suspending)
+		atomic_set(&ep->suspended, atomic_read(&ep->running));
+	atomic_set(&ep->running, 0);
+	for (i = 0; i < ep->num_urbs; i++) {
+		if (!ep->urbs[i].urb)
+			break;
+		usb_kill_urb(ep->urbs[i].urb);
+	}
+}
+
+/* wait until all URBs get freed */
+static void drain_urb_queue(struct snd_usb_midi2_endpoint *ep)
+{
+	if (!ep)
+		return;
+	guard(spinlock_irq)(&ep->lock);
+	atomic_set(&ep->running, 0);
+	wait_event_lock_irq_timeout(ep->wait,
+				    ep->disconnected ||
+				    ep->urb_free == ep->urb_free_mask,
+				    ep->lock, msecs_to_jiffies(500));
+}
+
+/* release URBs for an EP */
+static void free_midi_urbs(struct snd_usb_midi2_endpoint *ep)
+{
+	struct snd_usb_midi2_urb *ctx;
+	int i;
+
+	if (!ep)
+		return;
+	for (i = 0; i < NUM_URBS; ++i) {
+		ctx = &ep->urbs[i];
+		if (!ctx->urb)
+			break;
+		usb_free_coherent(ep->dev, ep->packets,
+				  ctx->urb->transfer_buffer,
+				  ctx->urb->transfer_dma);
+		usb_free_urb(ctx->urb);
+		ctx->urb = NULL;
+	}
+	ep->num_urbs = 0;
+}
+
+/* allocate URBs for an EP */
+/* the callers should handle allocation errors via free_midi_urbs() */
+static int alloc_midi_urbs(struct snd_usb_midi2_endpoint *ep)
+{
+	struct snd_usb_midi2_urb *ctx;
+	void (*comp)(struct urb *urb);
+	void *buffer;
+	int i, err;
+	int endpoint, len;
+
+	endpoint = ep->endpoint;
+	len = ep->packets;
+	if (ep->direction == STR_IN)
+		comp = input_urb_complete;
+	else
+		comp = output_urb_complete;
+
+	ep->num_urbs = 0;
+	ep->urb_free = ep->urb_free_mask = 0;
+	for (i = 0; i < NUM_URBS; i++) {
+		ctx = &ep->urbs[i];
+		ctx->index = i;
+		ctx->urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!ctx->urb) {
+			dev_err(&ep->dev->dev, "URB alloc failed\n");
+			return -ENOMEM;
+		}
+		ctx->ep = ep;
+		buffer = usb_alloc_coherent(ep->dev, len, GFP_KERNEL,
+					    &ctx->urb->transfer_dma);
+		if (!buffer) {
+			dev_err(&ep->dev->dev,
+				"URB buffer alloc failed (size %d)\n", len);
+			return -ENOMEM;
+		}
+		if (ep->interval)
+			usb_fill_int_urb(ctx->urb, ep->dev, ep->pipe,
+					 buffer, len, comp, ctx, ep->interval);
+		else
+			usb_fill_bulk_urb(ctx->urb, ep->dev, ep->pipe,
+					  buffer, len, comp, ctx);
+		err = usb_urb_ep_type_check(ctx->urb);
+		if (err < 0) {
+			dev_err(&ep->dev->dev, "invalid MIDI EP %x\n",
+				endpoint);
+			return err;
+		}
+		ctx->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+		ep->num_urbs++;
+	}
+	ep->urb_free = ep->urb_free_mask = GENMASK(ep->num_urbs - 1, 0);
+	return 0;
+}
+
+static struct snd_usb_midi2_endpoint *
+ump_to_endpoint(struct snd_ump_endpoint *ump, int dir)
+{
+	struct snd_usb_midi2_ump *rmidi = ump->private_data;
+
+	return rmidi ? rmidi->eps[dir] : NULL;
+}
+
+/* ump open callback */
+static int snd_usb_midi_v2_open(struct snd_ump_endpoint *ump, int dir)
+{
+	struct snd_usb_midi2_endpoint *ep = ump_to_endpoint(ump, dir);
+	int err = 0;
+
+	if (!ep || !ep->endpoint)
+		return -ENODEV;
+	if (ep->disconnected)
+		return -EIO;
+	if (ep->direction == STR_OUT) {
+		err = alloc_midi_urbs(ep);
+		if (err) {
+			free_midi_urbs(ep);
+			return err;
+		}
+	}
+	return 0;
+}
+
+/* ump close callback */
+static void snd_usb_midi_v2_close(struct snd_ump_endpoint *ump, int dir)
+{
+	struct snd_usb_midi2_endpoint *ep = ump_to_endpoint(ump, dir);
+
+	if (ep->direction == STR_OUT) {
+		kill_midi_urbs(ep, false);
+		drain_urb_queue(ep);
+		free_midi_urbs(ep);
+	}
+}
+
+/* ump trigger callback */
+static void snd_usb_midi_v2_trigger(struct snd_ump_endpoint *ump, int dir,
+				    int up)
+{
+	struct snd_usb_midi2_endpoint *ep = ump_to_endpoint(ump, dir);
+
+	atomic_set(&ep->running, up);
+	if (up && ep->direction == STR_OUT && !ep->disconnected)
+		submit_io_urbs(ep);
+}
+
+/* ump drain callback */
+static void snd_usb_midi_v2_drain(struct snd_ump_endpoint *ump, int dir)
+{
+	struct snd_usb_midi2_endpoint *ep = ump_to_endpoint(ump, dir);
+
+	drain_urb_queue(ep);
+}
+
+/* allocate and start all input streams */
+static int start_input_streams(struct snd_usb_midi2_interface *umidi)
+{
+	struct snd_usb_midi2_endpoint *ep;
+	int err;
+
+	list_for_each_entry(ep, &umidi->ep_list, list) {
+		if (ep->direction == STR_IN) {
+			err = alloc_midi_urbs(ep);
+			if (err < 0)
+				goto error;
+		}
+	}
+
+	list_for_each_entry(ep, &umidi->ep_list, list) {
+		if (ep->direction == STR_IN)
+			submit_io_urbs(ep);
+	}
+
+	return 0;
+
+ error:
+	list_for_each_entry(ep, &umidi->ep_list, list) {
+		if (ep->direction == STR_IN)
+			free_midi_urbs(ep);
+	}
+
+	return err;
+}
+
+static const struct snd_ump_ops snd_usb_midi_v2_ump_ops = {
+	.open = snd_usb_midi_v2_open,
+	.close = snd_usb_midi_v2_close,
+	.trigger = snd_usb_midi_v2_trigger,
+	.drain = snd_usb_midi_v2_drain,
+};
+
+/* create a USB MIDI 2.0 endpoint object */
+static int create_midi2_endpoint(struct snd_usb_midi2_interface *umidi,
+				 struct usb_host_endpoint *hostep,
+				 const struct usb_ms20_endpoint_descriptor *ms_ep)
+{
+	struct snd_usb_midi2_endpoint *ep;
+	int endpoint, dir;
+
+	usb_audio_dbg(umidi->chip, "Creating an EP 0x%02x, #GTB=%d\n",
+		      hostep->desc.bEndpointAddress,
+		      ms_ep->bNumGrpTrmBlock);
+
+	ep = kzalloc_obj(*ep);
+	if (!ep)
+		return -ENOMEM;
+
+	spin_lock_init(&ep->lock);
+	init_waitqueue_head(&ep->wait);
+	ep->dev = umidi->chip->dev;
+	endpoint = hostep->desc.bEndpointAddress;
+	dir = (endpoint & USB_DIR_IN) ? STR_IN : STR_OUT;
+
+	ep->endpoint = endpoint;
+	ep->direction = dir;
+	ep->ms_ep = ms_ep;
+	if (usb_endpoint_xfer_int(&hostep->desc))
+		ep->interval = hostep->desc.bInterval;
+	else
+		ep->interval = 0;
+	if (dir == STR_IN) {
+		if (ep->interval)
+			ep->pipe = usb_rcvintpipe(ep->dev, endpoint);
+		else
+			ep->pipe = usb_rcvbulkpipe(ep->dev, endpoint);
+	} else {
+		if (ep->interval)
+			ep->pipe = usb_sndintpipe(ep->dev, endpoint);
+		else
+			ep->pipe = usb_sndbulkpipe(ep->dev, endpoint);
+	}
+	ep->packets = usb_maxpacket(ep->dev, ep->pipe);
+	list_add_tail(&ep->list, &umidi->ep_list);
+
+	return 0;
+}
+
+/* destructor for endpoint; from snd_usb_midi_v2_free() */
+static void free_midi2_endpoint(struct snd_usb_midi2_endpoint *ep)
+{
+	list_del(&ep->list);
+	if (!ep->disconnected) {
+		ep->disconnected = 1;
+		kill_midi_urbs(ep, false);
+		drain_urb_queue(ep);
+	}
+	free_midi_urbs(ep);
+	kfree(ep);
+}
+
+/* call all endpoint destructors */
+static void free_all_midi2_endpoints(struct snd_usb_midi2_interface *umidi)
+{
+	struct snd_usb_midi2_endpoint *ep;
+
+	while (!list_empty(&umidi->ep_list)) {
+		ep = list_first_entry(&umidi->ep_list,
+				      struct snd_usb_midi2_endpoint, list);
+		free_midi2_endpoint(ep);
+	}
+}
+
+/* find a MIDI STREAMING descriptor with a given subtype */
+static void *find_usb_ms_endpoint_descriptor(struct usb_host_endpoint *hostep,
+					     unsigned char subtype)
+{
+	unsigned char *extra = hostep->extra;
+	int extralen = hostep->extralen;
+
+	while (extralen > 3) {
+		struct usb_ms_endpoint_descriptor *ms_ep =
+			(struct usb_ms_endpoint_descriptor *)extra;
+		int length = ms_ep->bLength;
+
+		if (!length || length > extralen)
+			break;
+
+		if (length > 3 &&
+		    ms_ep->bDescriptorType == USB_DT_CS_ENDPOINT &&
+		    ms_ep->bDescriptorSubtype == subtype)
+			return ms_ep;
+		extralen -= length;
+		extra += length;
+	}
+	return NULL;
+}
+
+/* get the full group terminal block descriptors and return the size */
+static int get_group_terminal_block_descs(struct snd_usb_midi2_interface *umidi)
+{
+	struct usb_host_interface *hostif = umidi->hostif;
+	struct usb_device *dev = umidi->chip->dev;
+	struct usb_ms20_gr_trm_block_header_descriptor header = { 0 };
+	unsigned char *data;
+	int err, size;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      USB_REQ_GET_DESCRIPTOR,
+			      USB_RECIP_INTERFACE | USB_TYPE_STANDARD | USB_DIR_IN,
+			      USB_DT_CS_GR_TRM_BLOCK << 8 | hostif->desc.bAlternateSetting,
+			      hostif->desc.bInterfaceNumber,
+			      &header, sizeof(header));
+	if (err < 0)
+		return err;
+	size = __le16_to_cpu(header.wTotalLength);
+	if (!size) {
+		dev_err(&dev->dev, "Failed to get GTB descriptors for %d:%d\n",
+			hostif->desc.bInterfaceNumber, hostif->desc.bAlternateSetting);
+		return -EINVAL;
+	}
+
+	data = kzalloc(size, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      USB_REQ_GET_DESCRIPTOR,
+			      USB_RECIP_INTERFACE | USB_TYPE_STANDARD | USB_DIR_IN,
+			      USB_DT_CS_GR_TRM_BLOCK << 8 | hostif->desc.bAlternateSetting,
+			      hostif->desc.bInterfaceNumber, data, size);
+	if (err < 0) {
+		kfree(data);
+		return err;
+	}
+
+	umidi->blk_descs = data;
+	umidi->blk_desc_size = size;
+	return 0;
+}
+
+/* find the corresponding group terminal block descriptor */
+static const struct usb_ms20_gr_trm_block_descriptor *
+find_group_terminal_block(struct snd_usb_midi2_interface *umidi, int id)
+{
+	const unsigned char *data = umidi->blk_descs;
+	int size = umidi->blk_desc_size;
+	const struct usb_ms20_gr_trm_block_descriptor *desc;
+
+	size -= sizeof(struct usb_ms20_gr_trm_block_header_descriptor);
+	data += sizeof(struct usb_ms20_gr_trm_block_header_descriptor);
+	while (size > 0 && *data && *data <= size) {
+		desc = (const struct usb_ms20_gr_trm_block_descriptor *)data;
+		if (desc->bLength >= sizeof(*desc) &&
+		    desc->bDescriptorType == USB_DT_CS_GR_TRM_BLOCK &&
+		    desc->bDescriptorSubtype == USB_MS_GR_TRM_BLOCK &&
+		    desc->bGrpTrmBlkID == id)
+			return desc;
+		size -= *data;
+		data += *data;
+	}
+
+	return NULL;
+}
+
+/* fill up the information from GTB */
+static int parse_group_terminal_block(struct snd_usb_midi2_ump *rmidi,
+				      const struct usb_ms20_gr_trm_block_descriptor *desc)
+{
+	struct snd_ump_endpoint *ump = rmidi->ump;
+	unsigned int protocol, protocol_caps;
+
+	/* set default protocol */
+	switch (desc->bMIDIProtocol) {
+	case USB_MS_MIDI_PROTO_1_0_64:
+	case USB_MS_MIDI_PROTO_1_0_64_JRTS:
+	case USB_MS_MIDI_PROTO_1_0_128:
+	case USB_MS_MIDI_PROTO_1_0_128_JRTS:
+		protocol = SNDRV_UMP_EP_INFO_PROTO_MIDI1;
+		break;
+	case USB_MS_MIDI_PROTO_2_0:
+	case USB_MS_MIDI_PROTO_2_0_JRTS:
+		protocol = SNDRV_UMP_EP_INFO_PROTO_MIDI2;
+		break;
+	default:
+		return 0;
+	}
+
+	if (!ump->info.protocol)
+		ump->info.protocol = protocol;
+
+	protocol_caps = protocol;
+	switch (desc->bMIDIProtocol) {
+	case USB_MS_MIDI_PROTO_1_0_64_JRTS:
+	case USB_MS_MIDI_PROTO_1_0_128_JRTS:
+	case USB_MS_MIDI_PROTO_2_0_JRTS:
+		protocol_caps |= SNDRV_UMP_EP_INFO_PROTO_JRTS_TX |
+			SNDRV_UMP_EP_INFO_PROTO_JRTS_RX;
+		break;
+	}
+
+	ump->info.protocol_caps |= protocol_caps;
+	return 0;
+}
+
+/* allocate and parse for each assigned group terminal block */
+static int parse_group_terminal_blocks(struct snd_usb_midi2_interface *umidi)
+{
+	struct snd_usb_midi2_ump *rmidi;
+	const struct usb_ms20_gr_trm_block_descriptor *desc;
+	int err;
+
+	err = get_group_terminal_block_descs(umidi);
+	if (err < 0)
+		return err;
+	if (!umidi->blk_descs)
+		return 0;
+
+	list_for_each_entry(rmidi, &umidi->rawmidi_list, list) {
+		desc = find_group_terminal_block(umidi, rmidi->usb_block_id);
+		if (!desc)
+			continue;
+		err = parse_group_terminal_block(rmidi, desc);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/* parse endpoints included in the given interface and create objects */
+static int parse_midi_2_0_endpoints(struct snd_usb_midi2_interface *umidi)
+{
+	struct usb_host_interface *hostif = umidi->hostif;
+	struct usb_host_endpoint *hostep;
+	struct usb_ms20_endpoint_descriptor *ms_ep;
+	int i, err;
+
+	for (i = 0; i < hostif->desc.bNumEndpoints; i++) {
+		hostep = &hostif->endpoint[i];
+		if (!usb_endpoint_xfer_bulk(&hostep->desc) &&
+		    !usb_endpoint_xfer_int(&hostep->desc))
+			continue;
+		ms_ep = find_usb_ms_endpoint_descriptor(hostep, USB_MS_GENERAL_2_0);
+		if (!ms_ep)
+			continue;
+		if (ms_ep->bLength <= sizeof(*ms_ep))
+			continue;
+		if (!ms_ep->bNumGrpTrmBlock)
+			continue;
+		if (ms_ep->bLength < sizeof(*ms_ep) + ms_ep->bNumGrpTrmBlock)
+			continue;
+		err = create_midi2_endpoint(umidi, hostep, ms_ep);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static void free_ump_private_data(struct snd_ump_endpoint *ump)
+{
+	struct snd_usb_midi2_ump *rmidi = ump->private_data;
+
+	if (rmidi)
+		rmidi->ump = NULL;
+}
+
+static void free_all_midi2_umps(struct snd_usb_midi2_interface *umidi)
+{
+	struct snd_usb_midi2_ump *rmidi;
+
+	while (!list_empty(&umidi->rawmidi_list)) {
+		rmidi = list_first_entry(&umidi->rawmidi_list,
+					 struct snd_usb_midi2_ump, list);
+		list_del(&rmidi->list);
+		if (rmidi->ump)
+			rmidi->ump->private_data = NULL;
+		kfree(rmidi);
+	}
+}
+
+static int create_midi2_ump(struct snd_usb_midi2_interface *umidi,
+			    struct snd_usb_midi2_endpoint *ep_in,
+			    struct snd_usb_midi2_endpoint *ep_out,
+			    int blk_id)
+{
+	struct snd_usb_midi2_ump *rmidi;
+	struct snd_ump_endpoint *ump;
+	int input, output;
+	char idstr[16];
+	int err;
+
+	rmidi = kzalloc_obj(*rmidi);
+	if (!rmidi)
+		return -ENOMEM;
+	INIT_LIST_HEAD(&rmidi->list);
+	rmidi->dev = umidi->chip->dev;
+	rmidi->umidi = umidi;
+	rmidi->usb_block_id = blk_id;
+
+	rmidi->index = umidi->chip->num_rawmidis;
+	snprintf(idstr, sizeof(idstr), "UMP %d", rmidi->index);
+	input = ep_in ? 1 : 0;
+	output = ep_out ? 1 : 0;
+	err = snd_ump_endpoint_new(umidi->chip->card, idstr, rmidi->index,
+				   output, input, &ump);
+	if (err < 0) {
+		usb_audio_dbg(umidi->chip, "Failed to create a UMP object\n");
+		kfree(rmidi);
+		return err;
+	}
+
+	rmidi->ump = ump;
+	umidi->chip->num_rawmidis++;
+
+	ump->private_data = rmidi;
+	ump->ops = &snd_usb_midi_v2_ump_ops;
+	ump->private_free = free_ump_private_data;
+
+	rmidi->eps[STR_IN] = ep_in;
+	rmidi->eps[STR_OUT] = ep_out;
+	if (ep_in) {
+		ep_in->pair = ep_out;
+		ep_in->rmidi = rmidi;
+		ep_in->ump = ump;
+	}
+	if (ep_out) {
+		ep_out->pair = ep_in;
+		ep_out->rmidi = rmidi;
+		ep_out->ump = ump;
+	}
+
+	list_add_tail(&rmidi->list, &umidi->rawmidi_list);
+	return 0;
+}
+
+/* find the UMP EP with the given USB block id */
+static struct snd_usb_midi2_ump *
+find_midi2_ump(struct snd_usb_midi2_interface *umidi, int blk_id)
+{
+	struct snd_usb_midi2_ump *rmidi;
+
+	list_for_each_entry(rmidi, &umidi->rawmidi_list, list) {
+		if (rmidi->usb_block_id == blk_id)
+			return rmidi;
+	}
+	return NULL;
+}
+
+/* look for the matching output endpoint and create UMP object if found */
+static int find_matching_ep_partner(struct snd_usb_midi2_interface *umidi,
+				    struct snd_usb_midi2_endpoint *ep,
+				    int blk_id)
+{
+	struct snd_usb_midi2_endpoint *pair_ep;
+	int blk;
+
+	usb_audio_dbg(umidi->chip, "Looking for a pair for EP-in 0x%02x\n",
+		      ep->endpoint);
+	list_for_each_entry(pair_ep, &umidi->ep_list, list) {
+		if (pair_ep->direction != STR_OUT)
+			continue;
+		if (pair_ep->pair)
+			continue; /* already paired */
+		for (blk = 0; blk < pair_ep->ms_ep->bNumGrpTrmBlock; blk++) {
+			if (pair_ep->ms_ep->baAssoGrpTrmBlkID[blk] == blk_id) {
+				usb_audio_dbg(umidi->chip,
+					      "Found a match with EP-out 0x%02x blk %d\n",
+					      pair_ep->endpoint, blk);
+				return create_midi2_ump(umidi, ep, pair_ep, blk_id);
+			}
+		}
+	}
+	return 0;
+}
+
+/* Call UMP helper to parse UMP endpoints;
+ * this needs to be called after starting the input streams for bi-directional
+ * communications
+ */
+static int parse_ump_endpoints(struct snd_usb_midi2_interface *umidi)
+{
+	struct snd_usb_midi2_ump *rmidi;
+	int err;
+
+	list_for_each_entry(rmidi, &umidi->rawmidi_list, list) {
+		if (!rmidi->ump ||
+		    !(rmidi->ump->core.info_flags & SNDRV_RAWMIDI_INFO_DUPLEX))
+			continue;
+		err = snd_ump_parse_endpoint(rmidi->ump);
+		if (!err) {
+			rmidi->ump_parsed = true;
+		} else {
+			if (err == -ENOMEM)
+				return err;
+			/* fall back to GTB later */
+		}
+	}
+	return 0;
+}
+
+/* create a UMP block from a GTB entry */
+static int create_gtb_block(struct snd_usb_midi2_ump *rmidi, int dir, int blk)
+{
+	struct snd_usb_midi2_interface *umidi = rmidi->umidi;
+	const struct usb_ms20_gr_trm_block_descriptor *desc;
+	struct snd_ump_block *fb;
+	int type, err;
+
+	desc = find_group_terminal_block(umidi, blk);
+	if (!desc)
+		return 0;
+
+	usb_audio_dbg(umidi->chip,
+		      "GTB %d: type=%d, group=%d/%d, protocol=%d, in bw=%d, out bw=%d\n",
+		      blk, desc->bGrpTrmBlkType, desc->nGroupTrm,
+		      desc->nNumGroupTrm, desc->bMIDIProtocol,
+		      __le16_to_cpu(desc->wMaxInputBandwidth),
+		      __le16_to_cpu(desc->wMaxOutputBandwidth));
+
+	/* assign the direction */
+	switch (desc->bGrpTrmBlkType) {
+	case USB_MS_GR_TRM_BLOCK_TYPE_BIDIRECTIONAL:
+		type = SNDRV_UMP_DIR_BIDIRECTION;
+		break;
+	case USB_MS_GR_TRM_BLOCK_TYPE_INPUT_ONLY:
+		type = SNDRV_UMP_DIR_INPUT;
+		break;
+	case USB_MS_GR_TRM_BLOCK_TYPE_OUTPUT_ONLY:
+		type = SNDRV_UMP_DIR_OUTPUT;
+		break;
+	default:
+		usb_audio_dbg(umidi->chip, "Unsupported GTB type %d\n",
+			      desc->bGrpTrmBlkType);
+		return 0; /* unsupported */
+	}
+
+	/* guess work: set blk-1 as the (0-based) block ID */
+	err = snd_ump_block_new(rmidi->ump, blk - 1, type,
+				desc->nGroupTrm, desc->nNumGroupTrm,
+				&fb);
+	if (err == -EBUSY)
+		return 0; /* already present */
+	else if (err)
+		return err;
+
+	if (desc->iBlockItem)
+		usb_string(rmidi->dev, desc->iBlockItem,
+			   fb->info.name, sizeof(fb->info.name));
+
+	if (__le16_to_cpu(desc->wMaxInputBandwidth) == 1 ||
+	    __le16_to_cpu(desc->wMaxOutputBandwidth) == 1)
+		fb->info.flags |= SNDRV_UMP_BLOCK_IS_MIDI1 |
+			SNDRV_UMP_BLOCK_IS_LOWSPEED;
+
+	/* if MIDI 2.0 protocol is supported and yet the GTB shows MIDI 1.0,
+	 * treat it as a MIDI 1.0-specific block
+	 */
+	if (rmidi->ump->info.protocol_caps & SNDRV_UMP_EP_INFO_PROTO_MIDI2) {
+		switch (desc->bMIDIProtocol) {
+		case USB_MS_MIDI_PROTO_1_0_64:
+		case USB_MS_MIDI_PROTO_1_0_64_JRTS:
+		case USB_MS_MIDI_PROTO_1_0_128:
+		case USB_MS_MIDI_PROTO_1_0_128_JRTS:
+			fb->info.flags |= SNDRV_UMP_BLOCK_IS_MIDI1;
+			break;
+		}
+	}
+
+	snd_ump_update_group_attrs(rmidi->ump);
+
+	usb_audio_dbg(umidi->chip,
+		      "Created a UMP block %d from GTB, name=%s, flags=0x%x\n",
+		      blk, fb->info.name, fb->info.flags);
+	return 0;
+}
+
+/* Create UMP blocks for each UMP EP */
+static int create_blocks_from_gtb(struct snd_usb_midi2_interface *umidi)
+{
+	struct snd_usb_midi2_ump *rmidi;
+	int i, blk, err, dir;
+
+	list_for_each_entry(rmidi, &umidi->rawmidi_list, list) {
+		if (!rmidi->ump)
+			continue;
+		/* Blocks have been already created? */
+		if (rmidi->ump_parsed || rmidi->ump->info.num_blocks)
+			continue;
+		/* GTB is static-only */
+		rmidi->ump->info.flags |= SNDRV_UMP_EP_INFO_STATIC_BLOCKS;
+		/* loop over GTBs */
+		for (dir = 0; dir < 2; dir++) {
+			if (!rmidi->eps[dir])
+				continue;
+			for (i = 0; i < rmidi->eps[dir]->ms_ep->bNumGrpTrmBlock; i++) {
+				blk = rmidi->eps[dir]->ms_ep->baAssoGrpTrmBlkID[i];
+				err = create_gtb_block(rmidi, dir, blk);
+				if (err < 0)
+					return err;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/* attach legacy rawmidis */
+static int attach_legacy_rawmidi(struct snd_usb_midi2_interface *umidi)
+{
+#if IS_ENABLED(CONFIG_SND_UMP_LEGACY_RAWMIDI)
+	struct snd_usb_midi2_ump *rmidi;
+	int err;
+
+	list_for_each_entry(rmidi, &umidi->rawmidi_list, list) {
+		err = snd_ump_attach_legacy_rawmidi(rmidi->ump,
+						    "Legacy MIDI",
+						    umidi->chip->num_rawmidis);
+		if (err < 0)
+			return err;
+		umidi->chip->num_rawmidis++;
+	}
+#endif
+	return 0;
+}
+
+static void snd_usb_midi_v2_free(struct snd_usb_midi2_interface *umidi)
+{
+	free_all_midi2_endpoints(umidi);
+	free_all_midi2_umps(umidi);
+	list_del(&umidi->list);
+	kfree(umidi->blk_descs);
+	kfree(umidi);
+}
+
+/* parse the interface for MIDI 2.0 */
+static int parse_midi_2_0(struct snd_usb_midi2_interface *umidi)
+{
+	struct snd_usb_midi2_endpoint *ep;
+	int blk, id, err;
+
+	/* First, create an object for each USB MIDI Endpoint */
+	err = parse_midi_2_0_endpoints(umidi);
+	if (err < 0)
+		return err;
+	if (list_empty(&umidi->ep_list)) {
+		usb_audio_warn(umidi->chip, "No MIDI endpoints found\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * Next, look for EP I/O pairs that are found in group terminal blocks
+	 * A UMP object is created for each EP I/O pair as bidirecitonal
+	 * UMP EP
+	 */
+	list_for_each_entry(ep, &umidi->ep_list, list) {
+		/* only input in this loop; output is matched in find_midi_ump() */
+		if (ep->direction != STR_IN)
+			continue;
+		for (blk = 0; blk < ep->ms_ep->bNumGrpTrmBlock; blk++) {
+			id = ep->ms_ep->baAssoGrpTrmBlkID[blk];
+			err = find_matching_ep_partner(umidi, ep, id);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	/*
+	 * For the remaining EPs, treat as singles, create a UMP object with
+	 * unidirectional EP
+	 */
+	list_for_each_entry(ep, &umidi->ep_list, list) {
+		if (ep->rmidi)
+			continue; /* already paired */
+		for (blk = 0; blk < ep->ms_ep->bNumGrpTrmBlock; blk++) {
+			id = ep->ms_ep->baAssoGrpTrmBlkID[blk];
+			if (find_midi2_ump(umidi, id))
+				continue;
+			usb_audio_dbg(umidi->chip,
+				      "Creating a unidirection UMP for EP=0x%02x, blk=%d\n",
+				      ep->endpoint, id);
+			if (ep->direction == STR_IN)
+				err = create_midi2_ump(umidi, ep, NULL, id);
+			else
+				err = create_midi2_ump(umidi, NULL, ep, id);
+			if (err < 0)
+				return err;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+/* is the given interface for MIDI 2.0? */
+static bool is_midi2_altset(struct usb_host_interface *hostif)
+{
+	struct usb_ms_header_descriptor *ms_header =
+		(struct usb_ms_header_descriptor *)hostif->extra;
+
+	if (hostif->extralen < 7 ||
+	    ms_header->bLength < 7 ||
+	    ms_header->bDescriptorType != USB_DT_CS_INTERFACE ||
+	    ms_header->bDescriptorSubtype != UAC_HEADER)
+		return false;
+
+	return le16_to_cpu(ms_header->bcdMSC) == USB_MS_REV_MIDI_2_0;
+}
+
+/* change the altsetting */
+static int set_altset(struct snd_usb_midi2_interface *umidi)
+{
+	usb_audio_dbg(umidi->chip, "Setting host iface %d:%d\n",
+		      umidi->hostif->desc.bInterfaceNumber,
+		      umidi->hostif->desc.bAlternateSetting);
+	return usb_set_interface(umidi->chip->dev,
+				 umidi->hostif->desc.bInterfaceNumber,
+				 umidi->hostif->desc.bAlternateSetting);
+}
+
+/* fill UMP Endpoint name string from USB descriptor */
+static void fill_ump_ep_name(struct snd_ump_endpoint *ump,
+			     struct usb_device *dev, int id)
+{
+	int len;
+
+	usb_string(dev, id, ump->info.name, sizeof(ump->info.name));
+
+	/* trim superfluous "MIDI" suffix */
+	len = strlen(ump->info.name);
+	if (len > 5 && !strcmp(ump->info.name + len - 5, " MIDI"))
+		ump->info.name[len - 5] = 0;
+}
+
+/* fill the fallback name string for each rawmidi instance */
+static void set_fallback_rawmidi_names(struct snd_usb_midi2_interface *umidi)
+{
+	struct usb_device *dev = umidi->chip->dev;
+	struct snd_usb_midi2_ump *rmidi;
+	struct snd_ump_endpoint *ump;
+
+	list_for_each_entry(rmidi, &umidi->rawmidi_list, list) {
+		ump = rmidi->ump;
+		/* fill UMP EP name from USB descriptors */
+		if (!*ump->info.name && umidi->hostif->desc.iInterface)
+			fill_ump_ep_name(ump, dev, umidi->hostif->desc.iInterface);
+		else if (!*ump->info.name && dev->descriptor.iProduct)
+			fill_ump_ep_name(ump, dev, dev->descriptor.iProduct);
+		/* fill fallback name */
+		if (!*ump->info.name)
+			scnprintf(ump->info.name, sizeof(ump->info.name),
+				  "USB MIDI %d", rmidi->index);
+		/* copy as rawmidi name if not set */
+		if (!*ump->core.name)
+			strscpy(ump->core.name, ump->info.name,
+				sizeof(ump->core.name));
+		/* use serial number string as unique UMP product id */
+		if (!*ump->info.product_id && dev->serial && *dev->serial)
+			strscpy(ump->info.product_id, dev->serial);
+	}
+}
+
+/* create MIDI interface; fallback to MIDI 1.0 if needed */
+int snd_usb_midi_v2_create(struct snd_usb_audio *chip,
+			   struct usb_interface *iface,
+			   const struct snd_usb_audio_quirk *quirk,
+			   unsigned int usb_id)
+{
+	struct snd_usb_midi2_interface *umidi;
+	struct usb_host_interface *hostif;
+	int err;
+
+	usb_audio_dbg(chip, "Parsing interface %d...\n",
+		      iface->altsetting[0].desc.bInterfaceNumber);
+
+	/* fallback to MIDI 1.0? */
+	if (!midi2_enable) {
+		usb_audio_info(chip, "Falling back to MIDI 1.0 by module option\n");
+		goto fallback_to_midi1;
+	}
+	if ((quirk && quirk->type != QUIRK_MIDI_STANDARD_INTERFACE) ||
+	    iface->num_altsetting < 2) {
+		usb_audio_info(chip, "Quirk or no altset; falling back to MIDI 1.0\n");
+		goto fallback_to_midi1;
+	}
+	hostif = &iface->altsetting[1];
+	if (!is_midi2_altset(hostif)) {
+		usb_audio_info(chip, "No MIDI 2.0 at altset 1, falling back to MIDI 1.0\n");
+		goto fallback_to_midi1;
+	}
+	if (!hostif->desc.bNumEndpoints) {
+		usb_audio_info(chip, "No endpoint at altset 1, falling back to MIDI 1.0\n");
+		goto fallback_to_midi1;
+	}
+
+	usb_audio_dbg(chip, "Creating a MIDI 2.0 instance for %d:%d\n",
+		      hostif->desc.bInterfaceNumber,
+		      hostif->desc.bAlternateSetting);
+
+	umidi = kzalloc_obj(*umidi);
+	if (!umidi)
+		return -ENOMEM;
+	umidi->chip = chip;
+	umidi->iface = iface;
+	umidi->hostif = hostif;
+	INIT_LIST_HEAD(&umidi->rawmidi_list);
+	INIT_LIST_HEAD(&umidi->ep_list);
+
+	list_add_tail(&umidi->list, &chip->midi_v2_list);
+
+	err = set_altset(umidi);
+	if (err < 0) {
+		usb_audio_err(chip, "Failed to set altset\n");
+		goto error;
+	}
+
+	/* assume only altset 1 corresponding to MIDI 2.0 interface */
+	err = parse_midi_2_0(umidi);
+	if (err < 0) {
+		usb_audio_err(chip, "Failed to parse MIDI 2.0 interface\n");
+		goto error;
+	}
+
+	/* parse USB group terminal blocks */
+	err = parse_group_terminal_blocks(umidi);
+	if (err < 0) {
+		usb_audio_err(chip, "Failed to parse GTB\n");
+		goto error;
+	}
+
+	err = start_input_streams(umidi);
+	if (err < 0) {
+		usb_audio_err(chip, "Failed to start input streams\n");
+		goto error;
+	}
+
+	if (midi2_ump_probe) {
+		err = parse_ump_endpoints(umidi);
+		if (err < 0) {
+			usb_audio_err(chip, "Failed to parse UMP endpoint\n");
+			goto error;
+		}
+	}
+
+	err = create_blocks_from_gtb(umidi);
+	if (err < 0) {
+		usb_audio_err(chip, "Failed to create GTB blocks\n");
+		goto error;
+	}
+
+	set_fallback_rawmidi_names(umidi);
+
+	err = attach_legacy_rawmidi(umidi);
+	if (err < 0) {
+		usb_audio_err(chip, "Failed to create legacy rawmidi\n");
+		goto error;
+	}
+
+	return 0;
+
+ error:
+	snd_usb_midi_v2_free(umidi);
+	return err;
+
+ fallback_to_midi1:
+	return __snd_usbmidi_create(chip->card, iface, &chip->midi_list,
+				    quirk, usb_id, &chip->num_rawmidis);
+}
+
+static void suspend_midi2_endpoint(struct snd_usb_midi2_endpoint *ep)
+{
+	kill_midi_urbs(ep, true);
+	drain_urb_queue(ep);
+}
+
+void snd_usb_midi_v2_suspend_all(struct snd_usb_audio *chip)
+{
+	struct snd_usb_midi2_interface *umidi;
+	struct snd_usb_midi2_endpoint *ep;
+
+	list_for_each_entry(umidi, &chip->midi_v2_list, list) {
+		list_for_each_entry(ep, &umidi->ep_list, list)
+			suspend_midi2_endpoint(ep);
+	}
+}
+
+static void resume_midi2_endpoint(struct snd_usb_midi2_endpoint *ep)
+{
+	atomic_set(&ep->running, atomic_read(&ep->suspended));
+	atomic_set(&ep->suspended, 0);
+
+	if (ep->direction == STR_IN || atomic_read(&ep->running))
+		submit_io_urbs(ep);
+}
+
+void snd_usb_midi_v2_resume_all(struct snd_usb_audio *chip)
+{
+	struct snd_usb_midi2_interface *umidi;
+	struct snd_usb_midi2_endpoint *ep;
+
+	list_for_each_entry(umidi, &chip->midi_v2_list, list) {
+		set_altset(umidi);
+		list_for_each_entry(ep, &umidi->ep_list, list)
+			resume_midi2_endpoint(ep);
+	}
+}
+
+void snd_usb_midi_v2_disconnect_all(struct snd_usb_audio *chip)
+{
+	struct snd_usb_midi2_interface *umidi;
+	struct snd_usb_midi2_endpoint *ep;
+
+	list_for_each_entry(umidi, &chip->midi_v2_list, list) {
+		umidi->disconnected = 1;
+		list_for_each_entry(ep, &umidi->ep_list, list) {
+			ep->disconnected = 1;
+			kill_midi_urbs(ep, false);
+			drain_urb_queue(ep);
+		}
+	}
+}
+
+/* release the MIDI instance */
+void snd_usb_midi_v2_free_all(struct snd_usb_audio *chip)
+{
+	struct snd_usb_midi2_interface *umidi, *next;
+
+	list_for_each_entry_safe(umidi, next, &chip->midi_v2_list, list)
+		snd_usb_midi_v2_free(umidi);
+}
diff --git a/sound/usb/midi2.h b/sound/usb/midi2.h
new file mode 100644
index 000000000..94a65fcbd
--- /dev/null
+++ b/sound/usb/midi2.h
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#ifndef __USB_AUDIO_MIDI2_H
+#define __USB_AUDIO_MIDI2_H
+
+#include "midi.h"
+
+#if IS_ENABLED(CONFIG_SND_USB_AUDIO_MIDI_V2)
+int snd_usb_midi_v2_create(struct snd_usb_audio *chip,
+			   struct usb_interface *iface,
+			   const struct snd_usb_audio_quirk *quirk,
+			   unsigned int usb_id);
+void snd_usb_midi_v2_suspend_all(struct snd_usb_audio *chip);
+void snd_usb_midi_v2_resume_all(struct snd_usb_audio *chip);
+void snd_usb_midi_v2_disconnect_all(struct snd_usb_audio *chip);
+void snd_usb_midi_v2_free_all(struct snd_usb_audio *chip);
+#else /* CONFIG_SND_USB_AUDIO_MIDI_V2 */
+/* fallback to MIDI 1.0 creation */
+static inline int snd_usb_midi_v2_create(struct snd_usb_audio *chip,
+					 struct usb_interface *iface,
+					 const struct snd_usb_audio_quirk *quirk,
+					 unsigned int usb_id)
+{
+	return __snd_usbmidi_create(chip->card, iface, &chip->midi_list,
+				    quirk, usb_id, &chip->num_rawmidis);
+}
+
+static inline void snd_usb_midi_v2_suspend_all(struct snd_usb_audio *chip) {}
+static inline void snd_usb_midi_v2_resume_all(struct snd_usb_audio *chip) {}
+static inline void snd_usb_midi_v2_disconnect_all(struct snd_usb_audio *chip) {}
+static inline void snd_usb_midi_v2_free_all(struct snd_usb_audio *chip) {}
+#endif /* CONFIG_SND_USB_AUDIO_MIDI_V2 */
+
+#endif /* __USB_AUDIO_MIDI2_H */
diff --git a/sound/usb/misc/Makefile b/sound/usb/misc/Makefile
new file mode 100644
index 000000000..3e9f4adc2
--- /dev/null
+++ b/sound/usb/misc/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+snd-ua101-y := ua101.o
+obj-$(CONFIG_SND_USB_UA101) += snd-ua101.o
diff --git a/sound/usb/misc/ua101.c b/sound/usb/misc/ua101.c
new file mode 100644
index 000000000..58d8a3cdc
--- /dev/null
+++ b/sound/usb/misc/ua101.c
@@ -0,0 +1,1352 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Edirol UA-101/UA-1000 driver
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include "../usbaudio.h"
+#include "../midi.h"
+
+MODULE_DESCRIPTION("Edirol UA-101/1000 driver");
+MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
+MODULE_LICENSE("GPL v2");
+
+/*
+ * Should not be lower than the minimum scheduling delay of the host
+ * controller.  Some Intel controllers need more than one frame; as long as
+ * that driver doesn't tell us about this, use 1.5 frames just to be sure.
+ */
+#define MIN_QUEUE_LENGTH	12
+/* Somewhat random. */
+#define MAX_QUEUE_LENGTH	30
+/*
+ * This magic value optimizes memory usage efficiency for the UA-101's packet
+ * sizes at all sample rates, taking into account the stupid cache pool sizes
+ * that usb_alloc_coherent() uses.
+ */
+#define DEFAULT_QUEUE_LENGTH	21
+
+#define MAX_PACKET_SIZE		672 /* hardware specific */
+#define MAX_MEMORY_BUFFERS	DIV_ROUND_UP(MAX_QUEUE_LENGTH, \
+					     PAGE_SIZE / MAX_PACKET_SIZE)
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
+static unsigned int queue_length = 21;
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "card index");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "enable card");
+module_param(queue_length, uint, 0644);
+MODULE_PARM_DESC(queue_length, "USB queue length in microframes, "
+		 __stringify(MIN_QUEUE_LENGTH)"-"__stringify(MAX_QUEUE_LENGTH));
+
+enum {
+	INTF_PLAYBACK,
+	INTF_CAPTURE,
+	INTF_MIDI,
+
+	INTF_COUNT
+};
+
+/* bits in struct ua101::states */
+enum {
+	USB_CAPTURE_RUNNING,
+	USB_PLAYBACK_RUNNING,
+	ALSA_CAPTURE_OPEN,
+	ALSA_PLAYBACK_OPEN,
+	ALSA_CAPTURE_RUNNING,
+	ALSA_PLAYBACK_RUNNING,
+	CAPTURE_URB_COMPLETED,
+	PLAYBACK_URB_COMPLETED,
+	DISCONNECTED,
+};
+
+struct ua101 {
+	struct usb_device *dev;
+	struct snd_card *card;
+	struct usb_interface *intf[INTF_COUNT];
+	int card_index;
+	struct snd_pcm *pcm;
+	struct list_head midi_list;
+	u64 format_bit;
+	unsigned int rate;
+	unsigned int packets_per_second;
+	spinlock_t lock;
+	struct mutex mutex;
+	unsigned long states;
+
+	/* FIFO to synchronize playback rate to capture rate */
+	unsigned int rate_feedback_start;
+	unsigned int rate_feedback_count;
+	u8 rate_feedback[MAX_QUEUE_LENGTH];
+
+	struct list_head ready_playback_urbs;
+	struct work_struct playback_work;
+	wait_queue_head_t alsa_capture_wait;
+	wait_queue_head_t rate_feedback_wait;
+	wait_queue_head_t alsa_playback_wait;
+	struct ua101_stream {
+		struct snd_pcm_substream *substream;
+		unsigned int usb_pipe;
+		unsigned int channels;
+		unsigned int frame_bytes;
+		unsigned int max_packet_bytes;
+		unsigned int period_pos;
+		unsigned int buffer_pos;
+		unsigned int queue_length;
+		struct ua101_urb {
+			struct urb *urb;
+			struct list_head ready_list;
+			struct ua101 *ua;
+		} urbs[MAX_QUEUE_LENGTH];
+		struct {
+			unsigned int size;
+			void *addr;
+			dma_addr_t dma;
+		} buffers[MAX_MEMORY_BUFFERS];
+	} capture, playback;
+};
+
+static DEFINE_MUTEX(devices_mutex);
+static unsigned int devices_used;
+static struct usb_driver ua101_driver;
+
+static void abort_alsa_playback(struct ua101 *ua);
+static void abort_alsa_capture(struct ua101 *ua);
+
+static const char *usb_error_string(int err)
+{
+	switch (err) {
+	case -ENODEV:
+		return "no device";
+	case -ENOENT:
+		return "endpoint not enabled";
+	case -EPIPE:
+		return "endpoint stalled";
+	case -ENOSPC:
+		return "not enough bandwidth";
+	case -ESHUTDOWN:
+		return "device disabled";
+	case -EHOSTUNREACH:
+		return "device suspended";
+	case -EINVAL:
+	case -EAGAIN:
+	case -EFBIG:
+	case -EMSGSIZE:
+		return "internal error";
+	default:
+		return "unknown error";
+	}
+}
+
+static void abort_usb_capture(struct ua101 *ua)
+{
+	if (test_and_clear_bit(USB_CAPTURE_RUNNING, &ua->states)) {
+		wake_up(&ua->alsa_capture_wait);
+		wake_up(&ua->rate_feedback_wait);
+	}
+}
+
+static void abort_usb_playback(struct ua101 *ua)
+{
+	if (test_and_clear_bit(USB_PLAYBACK_RUNNING, &ua->states))
+		wake_up(&ua->alsa_playback_wait);
+}
+
+static void playback_urb_complete(struct urb *urb)
+{
+	struct ua101_urb *ua_urb = urb->context;
+	struct ua101 *ua = ua_urb->ua;
+
+	if (unlikely(urb->status == -ENOENT ||	/* unlinked */
+		     urb->status == -ENODEV ||	/* device removed */
+		     urb->status == -ECONNRESET ||	/* unlinked */
+		     urb->status == -ESHUTDOWN)) {	/* device disabled */
+		abort_usb_playback(ua);
+		abort_alsa_playback(ua);
+		return;
+	}
+
+	if (test_bit(USB_PLAYBACK_RUNNING, &ua->states)) {
+		/* append URB to FIFO */
+		guard(spinlock_irqsave)(&ua->lock);
+		list_add_tail(&ua_urb->ready_list, &ua->ready_playback_urbs);
+		if (ua->rate_feedback_count > 0)
+			queue_work(system_highpri_wq, &ua->playback_work);
+		ua->playback.substream->runtime->delay -=
+				urb->iso_frame_desc[0].length /
+						ua->playback.frame_bytes;
+	}
+}
+
+static void first_playback_urb_complete(struct urb *urb)
+{
+	struct ua101_urb *ua_urb = urb->context;
+	struct ua101 *ua = ua_urb->ua;
+
+	urb->complete = playback_urb_complete;
+	playback_urb_complete(urb);
+
+	set_bit(PLAYBACK_URB_COMPLETED, &ua->states);
+	wake_up(&ua->alsa_playback_wait);
+}
+
+/* copy data from the ALSA ring buffer into the URB buffer */
+static bool copy_playback_data(struct ua101_stream *stream, struct urb *urb,
+			       unsigned int frames)
+{
+	struct snd_pcm_runtime *runtime;
+	unsigned int frame_bytes, frames1;
+	const u8 *source;
+
+	runtime = stream->substream->runtime;
+	frame_bytes = stream->frame_bytes;
+	source = runtime->dma_area + stream->buffer_pos * frame_bytes;
+	if (stream->buffer_pos + frames <= runtime->buffer_size) {
+		memcpy(urb->transfer_buffer, source, frames * frame_bytes);
+	} else {
+		/* wrap around at end of ring buffer */
+		frames1 = runtime->buffer_size - stream->buffer_pos;
+		memcpy(urb->transfer_buffer, source, frames1 * frame_bytes);
+		memcpy(urb->transfer_buffer + frames1 * frame_bytes,
+		       runtime->dma_area, (frames - frames1) * frame_bytes);
+	}
+
+	stream->buffer_pos += frames;
+	if (stream->buffer_pos >= runtime->buffer_size)
+		stream->buffer_pos -= runtime->buffer_size;
+	stream->period_pos += frames;
+	if (stream->period_pos >= runtime->period_size) {
+		stream->period_pos -= runtime->period_size;
+		return true;
+	}
+	return false;
+}
+
+static inline void add_with_wraparound(struct ua101 *ua,
+				       unsigned int *value, unsigned int add)
+{
+	*value += add;
+	if (*value >= ua->playback.queue_length)
+		*value -= ua->playback.queue_length;
+}
+
+static void playback_work(struct work_struct *work)
+{
+	struct ua101 *ua = container_of(work, struct ua101, playback_work);
+	unsigned int frames;
+	struct ua101_urb *ua_urb;
+	struct urb *urb;
+	bool do_period_elapsed = false;
+	int err;
+
+	if (unlikely(!test_bit(USB_PLAYBACK_RUNNING, &ua->states)))
+		return;
+
+	/*
+	 * Synchronizing the playback rate to the capture rate is done by using
+	 * the same sequence of packet sizes for both streams.
+	 * Submitting a playback URB therefore requires both a ready URB and
+	 * the size of the corresponding capture packet, i.e., both playback
+	 * and capture URBs must have been completed.  Since the USB core does
+	 * not guarantee that playback and capture complete callbacks are
+	 * called alternately, we use two FIFOs for packet sizes and read URBs;
+	 * submitting playback URBs is possible as long as both FIFOs are
+	 * nonempty.
+	 */
+	scoped_guard(spinlock_irqsave, &ua->lock) {
+		while (ua->rate_feedback_count > 0 &&
+		       !list_empty(&ua->ready_playback_urbs)) {
+			/* take packet size out of FIFO */
+			frames = ua->rate_feedback[ua->rate_feedback_start];
+			add_with_wraparound(ua, &ua->rate_feedback_start, 1);
+			ua->rate_feedback_count--;
+
+			/* take URB out of FIFO */
+			ua_urb = list_first_entry(&ua->ready_playback_urbs,
+						  struct ua101_urb, ready_list);
+			list_del(&ua_urb->ready_list);
+			urb = ua_urb->urb;
+
+			/* fill packet with data or silence */
+			urb->iso_frame_desc[0].length =
+				frames * ua->playback.frame_bytes;
+			if (test_bit(ALSA_PLAYBACK_RUNNING, &ua->states))
+				do_period_elapsed |= copy_playback_data(&ua->playback,
+									urb,
+									frames);
+			else
+				memset(urb->transfer_buffer, 0,
+				       urb->iso_frame_desc[0].length);
+
+			/* and off you go ... */
+			err = usb_submit_urb(urb, GFP_ATOMIC);
+			if (unlikely(err < 0)) {
+				abort_usb_playback(ua);
+				abort_alsa_playback(ua);
+				dev_err(&ua->dev->dev, "USB request error %d: %s\n",
+					err, usb_error_string(err));
+				return;
+			}
+			ua->playback.substream->runtime->delay += frames;
+		}
+	}
+
+	if (do_period_elapsed)
+		snd_pcm_period_elapsed(ua->playback.substream);
+}
+
+/* copy data from the URB buffer into the ALSA ring buffer */
+static bool copy_capture_data(struct ua101_stream *stream, struct urb *urb,
+			      unsigned int frames)
+{
+	struct snd_pcm_runtime *runtime;
+	unsigned int frame_bytes, frames1;
+	u8 *dest;
+
+	runtime = stream->substream->runtime;
+	frame_bytes = stream->frame_bytes;
+	dest = runtime->dma_area + stream->buffer_pos * frame_bytes;
+	if (stream->buffer_pos + frames <= runtime->buffer_size) {
+		memcpy(dest, urb->transfer_buffer, frames * frame_bytes);
+	} else {
+		/* wrap around at end of ring buffer */
+		frames1 = runtime->buffer_size - stream->buffer_pos;
+		memcpy(dest, urb->transfer_buffer, frames1 * frame_bytes);
+		memcpy(runtime->dma_area,
+		       urb->transfer_buffer + frames1 * frame_bytes,
+		       (frames - frames1) * frame_bytes);
+	}
+
+	stream->buffer_pos += frames;
+	if (stream->buffer_pos >= runtime->buffer_size)
+		stream->buffer_pos -= runtime->buffer_size;
+	stream->period_pos += frames;
+	if (stream->period_pos >= runtime->period_size) {
+		stream->period_pos -= runtime->period_size;
+		return true;
+	}
+	return false;
+}
+
+static void capture_urb_complete(struct urb *urb)
+{
+	struct ua101_urb *ua_urb = urb->context;
+	struct ua101 *ua = ua_urb->ua;
+	struct ua101_stream *stream = &ua->capture;
+	unsigned int frames, write_ptr;
+	bool do_period_elapsed;
+	int err;
+
+	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
+		     urb->status == -ENODEV ||		/* device removed */
+		     urb->status == -ECONNRESET ||	/* unlinked */
+		     urb->status == -ESHUTDOWN))	/* device disabled */
+		goto stream_stopped;
+
+	if (urb->status >= 0 && urb->iso_frame_desc[0].status >= 0)
+		frames = urb->iso_frame_desc[0].actual_length /
+			stream->frame_bytes;
+	else
+		frames = 0;
+
+	scoped_guard(spinlock_irqsave, &ua->lock) {
+
+		if (frames > 0 && test_bit(ALSA_CAPTURE_RUNNING, &ua->states))
+			do_period_elapsed = copy_capture_data(stream, urb, frames);
+		else
+			do_period_elapsed = false;
+
+		if (test_bit(USB_CAPTURE_RUNNING, &ua->states)) {
+			err = usb_submit_urb(urb, GFP_ATOMIC);
+			if (unlikely(err < 0)) {
+				dev_err(&ua->dev->dev, "USB request error %d: %s\n",
+					err, usb_error_string(err));
+				goto stream_stopped;
+			}
+
+			/* append packet size to FIFO */
+			write_ptr = ua->rate_feedback_start;
+			add_with_wraparound(ua, &write_ptr, ua->rate_feedback_count);
+			ua->rate_feedback[write_ptr] = frames;
+			if (ua->rate_feedback_count < ua->playback.queue_length) {
+				ua->rate_feedback_count++;
+				if (ua->rate_feedback_count ==
+				    ua->playback.queue_length)
+					wake_up(&ua->rate_feedback_wait);
+			} else {
+				/*
+				 * Ring buffer overflow; this happens when the playback
+				 * stream is not running.  Throw away the oldest entry,
+				 * so that the playback stream, when it starts, sees
+				 * the most recent packet sizes.
+				 */
+				add_with_wraparound(ua, &ua->rate_feedback_start, 1);
+			}
+			if (test_bit(USB_PLAYBACK_RUNNING, &ua->states) &&
+			    !list_empty(&ua->ready_playback_urbs))
+				queue_work(system_highpri_wq, &ua->playback_work);
+		}
+	}
+
+	if (do_period_elapsed)
+		snd_pcm_period_elapsed(stream->substream);
+
+	return;
+
+stream_stopped:
+	abort_usb_playback(ua);
+	abort_usb_capture(ua);
+	abort_alsa_playback(ua);
+	abort_alsa_capture(ua);
+}
+
+static void first_capture_urb_complete(struct urb *urb)
+{
+	struct ua101_urb *ua_urb = urb->context;
+	struct ua101 *ua = ua_urb->ua;
+
+	urb->complete = capture_urb_complete;
+	capture_urb_complete(urb);
+
+	set_bit(CAPTURE_URB_COMPLETED, &ua->states);
+	wake_up(&ua->alsa_capture_wait);
+}
+
+static int submit_stream_urbs(struct ua101 *ua, struct ua101_stream *stream)
+{
+	unsigned int i;
+
+	for (i = 0; i < stream->queue_length; ++i) {
+		int err = usb_submit_urb(stream->urbs[i].urb, GFP_KERNEL);
+		if (err < 0) {
+			dev_err(&ua->dev->dev, "USB request error %d: %s\n",
+				err, usb_error_string(err));
+			return err;
+		}
+	}
+	return 0;
+}
+
+static void kill_stream_urbs(struct ua101_stream *stream)
+{
+	unsigned int i;
+
+	for (i = 0; i < stream->queue_length; ++i)
+		if (stream->urbs[i].urb)
+			usb_kill_urb(stream->urbs[i].urb);
+}
+
+static int enable_iso_interface(struct ua101 *ua, unsigned int intf_index)
+{
+	struct usb_host_interface *alts;
+
+	alts = ua->intf[intf_index]->cur_altsetting;
+	if (alts->desc.bAlternateSetting != 1) {
+		int err = usb_set_interface(ua->dev,
+					    alts->desc.bInterfaceNumber, 1);
+		if (err < 0) {
+			dev_err(&ua->dev->dev,
+				"cannot initialize interface; error %d: %s\n",
+				err, usb_error_string(err));
+			return err;
+		}
+	}
+	return 0;
+}
+
+static void disable_iso_interface(struct ua101 *ua, unsigned int intf_index)
+{
+	struct usb_host_interface *alts;
+
+	if (!ua->intf[intf_index])
+		return;
+
+	alts = ua->intf[intf_index]->cur_altsetting;
+	if (alts->desc.bAlternateSetting != 0) {
+		int err = usb_set_interface(ua->dev,
+					    alts->desc.bInterfaceNumber, 0);
+		if (err < 0 && !test_bit(DISCONNECTED, &ua->states))
+			dev_warn(&ua->dev->dev,
+				 "interface reset failed; error %d: %s\n",
+				 err, usb_error_string(err));
+	}
+}
+
+static void stop_usb_capture(struct ua101 *ua)
+{
+	clear_bit(USB_CAPTURE_RUNNING, &ua->states);
+
+	kill_stream_urbs(&ua->capture);
+
+	disable_iso_interface(ua, INTF_CAPTURE);
+}
+
+static int start_usb_capture(struct ua101 *ua)
+{
+	int err;
+
+	if (test_bit(DISCONNECTED, &ua->states))
+		return -ENODEV;
+
+	if (test_bit(USB_CAPTURE_RUNNING, &ua->states))
+		return 0;
+
+	kill_stream_urbs(&ua->capture);
+
+	err = enable_iso_interface(ua, INTF_CAPTURE);
+	if (err < 0)
+		return err;
+
+	clear_bit(CAPTURE_URB_COMPLETED, &ua->states);
+	ua->capture.urbs[0].urb->complete = first_capture_urb_complete;
+	ua->rate_feedback_start = 0;
+	ua->rate_feedback_count = 0;
+
+	set_bit(USB_CAPTURE_RUNNING, &ua->states);
+	err = submit_stream_urbs(ua, &ua->capture);
+	if (err < 0)
+		stop_usb_capture(ua);
+	return err;
+}
+
+static void stop_usb_playback(struct ua101 *ua)
+{
+	clear_bit(USB_PLAYBACK_RUNNING, &ua->states);
+
+	kill_stream_urbs(&ua->playback);
+
+	cancel_work_sync(&ua->playback_work);
+
+	disable_iso_interface(ua, INTF_PLAYBACK);
+}
+
+static int start_usb_playback(struct ua101 *ua)
+{
+	unsigned int i, frames;
+	struct urb *urb;
+	int err = 0;
+
+	if (test_bit(DISCONNECTED, &ua->states))
+		return -ENODEV;
+
+	if (test_bit(USB_PLAYBACK_RUNNING, &ua->states))
+		return 0;
+
+	kill_stream_urbs(&ua->playback);
+	cancel_work_sync(&ua->playback_work);
+
+	err = enable_iso_interface(ua, INTF_PLAYBACK);
+	if (err < 0)
+		return err;
+
+	clear_bit(PLAYBACK_URB_COMPLETED, &ua->states);
+	ua->playback.urbs[0].urb->complete =
+		first_playback_urb_complete;
+	scoped_guard(spinlock_irq, &ua->lock) {
+		INIT_LIST_HEAD(&ua->ready_playback_urbs);
+	}
+
+	/*
+	 * We submit the initial URBs all at once, so we have to wait for the
+	 * packet size FIFO to be full.
+	 */
+	wait_event(ua->rate_feedback_wait,
+		   ua->rate_feedback_count >= ua->playback.queue_length ||
+		   !test_bit(USB_CAPTURE_RUNNING, &ua->states) ||
+		   test_bit(DISCONNECTED, &ua->states));
+	if (test_bit(DISCONNECTED, &ua->states)) {
+		stop_usb_playback(ua);
+		return -ENODEV;
+	}
+	if (!test_bit(USB_CAPTURE_RUNNING, &ua->states)) {
+		stop_usb_playback(ua);
+		return -EIO;
+	}
+
+	for (i = 0; i < ua->playback.queue_length; ++i) {
+		/* all initial URBs contain silence */
+		scoped_guard(spinlock_irq, &ua->lock) {
+			frames = ua->rate_feedback[ua->rate_feedback_start];
+			add_with_wraparound(ua, &ua->rate_feedback_start, 1);
+			ua->rate_feedback_count--;
+		}
+		urb = ua->playback.urbs[i].urb;
+		urb->iso_frame_desc[0].length =
+			frames * ua->playback.frame_bytes;
+		memset(urb->transfer_buffer, 0,
+		       urb->iso_frame_desc[0].length);
+	}
+
+	set_bit(USB_PLAYBACK_RUNNING, &ua->states);
+	err = submit_stream_urbs(ua, &ua->playback);
+	if (err < 0)
+		stop_usb_playback(ua);
+	return err;
+}
+
+static void abort_alsa_capture(struct ua101 *ua)
+{
+	if (test_bit(ALSA_CAPTURE_RUNNING, &ua->states))
+		snd_pcm_stop_xrun(ua->capture.substream);
+}
+
+static void abort_alsa_playback(struct ua101 *ua)
+{
+	if (test_bit(ALSA_PLAYBACK_RUNNING, &ua->states))
+		snd_pcm_stop_xrun(ua->playback.substream);
+}
+
+static int set_stream_hw(struct ua101 *ua, struct snd_pcm_substream *substream,
+			 unsigned int channels)
+{
+	int err;
+
+	substream->runtime->hw.info =
+		SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_MMAP_VALID |
+		SNDRV_PCM_INFO_BATCH |
+		SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_BLOCK_TRANSFER |
+		SNDRV_PCM_INFO_FIFO_IN_FRAMES;
+	substream->runtime->hw.formats = ua->format_bit;
+	substream->runtime->hw.rates = snd_pcm_rate_to_rate_bit(ua->rate);
+	substream->runtime->hw.rate_min = ua->rate;
+	substream->runtime->hw.rate_max = ua->rate;
+	substream->runtime->hw.channels_min = channels;
+	substream->runtime->hw.channels_max = channels;
+	substream->runtime->hw.buffer_bytes_max = 45000 * 1024;
+	substream->runtime->hw.period_bytes_min = 1;
+	substream->runtime->hw.period_bytes_max = UINT_MAX;
+	substream->runtime->hw.periods_min = 2;
+	substream->runtime->hw.periods_max = UINT_MAX;
+	err = snd_pcm_hw_constraint_minmax(substream->runtime,
+					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
+					   1500000 / ua->packets_per_second,
+					   UINT_MAX);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_constraint_msbits(substream->runtime, 0, 32, 24);
+	return err;
+}
+
+static int capture_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	ua->capture.substream = substream;
+	err = set_stream_hw(ua, substream, ua->capture.channels);
+	if (err < 0)
+		return err;
+	substream->runtime->hw.fifo_size =
+		DIV_ROUND_CLOSEST(ua->rate, ua->packets_per_second);
+	substream->runtime->delay = substream->runtime->hw.fifo_size;
+
+	guard(mutex)(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err >= 0)
+		set_bit(ALSA_CAPTURE_OPEN, &ua->states);
+	return err;
+}
+
+static int playback_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	ua->playback.substream = substream;
+	err = set_stream_hw(ua, substream, ua->playback.channels);
+	if (err < 0)
+		return err;
+	substream->runtime->hw.fifo_size =
+		DIV_ROUND_CLOSEST(ua->rate * ua->playback.queue_length,
+				  ua->packets_per_second);
+
+	guard(mutex)(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err < 0)
+		return err;
+	err = start_usb_playback(ua);
+	if (err < 0) {
+		if (!test_bit(ALSA_CAPTURE_OPEN, &ua->states))
+			stop_usb_capture(ua);
+		return err;
+	}
+	set_bit(ALSA_PLAYBACK_OPEN, &ua->states);
+	return 0;
+}
+
+static int capture_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+
+	guard(mutex)(&ua->mutex);
+	clear_bit(ALSA_CAPTURE_OPEN, &ua->states);
+	if (!test_bit(ALSA_PLAYBACK_OPEN, &ua->states))
+		stop_usb_capture(ua);
+	return 0;
+}
+
+static int playback_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+
+	guard(mutex)(&ua->mutex);
+	stop_usb_playback(ua);
+	clear_bit(ALSA_PLAYBACK_OPEN, &ua->states);
+	if (!test_bit(ALSA_CAPTURE_OPEN, &ua->states))
+		stop_usb_capture(ua);
+	return 0;
+}
+
+static int capture_pcm_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *hw_params)
+{
+	struct ua101 *ua = substream->private_data;
+
+	guard(mutex)(&ua->mutex);
+	return start_usb_capture(ua);
+}
+
+static int playback_pcm_hw_params(struct snd_pcm_substream *substream,
+				  struct snd_pcm_hw_params *hw_params)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	guard(mutex)(&ua->mutex);
+	err = start_usb_capture(ua);
+	if (err >= 0)
+		err = start_usb_playback(ua);
+	return err;
+}
+
+static int capture_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	scoped_guard(mutex, &ua->mutex) {
+		err = start_usb_capture(ua);
+	}
+	if (err < 0)
+		return err;
+
+	/*
+	 * The EHCI driver schedules the first packet of an iso stream at 10 ms
+	 * in the future, i.e., no data is actually captured for that long.
+	 * Take the wait here so that the stream is known to be actually
+	 * running when the start trigger has been called.
+	 */
+	wait_event(ua->alsa_capture_wait,
+		   test_bit(CAPTURE_URB_COMPLETED, &ua->states) ||
+		   !test_bit(USB_CAPTURE_RUNNING, &ua->states));
+	if (test_bit(DISCONNECTED, &ua->states))
+		return -ENODEV;
+	if (!test_bit(USB_CAPTURE_RUNNING, &ua->states))
+		return -EIO;
+
+	ua->capture.period_pos = 0;
+	ua->capture.buffer_pos = 0;
+	return 0;
+}
+
+static int playback_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct ua101 *ua = substream->private_data;
+	int err;
+
+	scoped_guard(mutex, &ua->mutex) {
+		err = start_usb_capture(ua);
+		if (err >= 0)
+			err = start_usb_playback(ua);
+	}
+	if (err < 0)
+		return err;
+
+	/* see the comment in capture_pcm_prepare() */
+	wait_event(ua->alsa_playback_wait,
+		   test_bit(PLAYBACK_URB_COMPLETED, &ua->states) ||
+		   !test_bit(USB_PLAYBACK_RUNNING, &ua->states));
+	if (test_bit(DISCONNECTED, &ua->states))
+		return -ENODEV;
+	if (!test_bit(USB_PLAYBACK_RUNNING, &ua->states))
+		return -EIO;
+
+	substream->runtime->delay = 0;
+	ua->playback.period_pos = 0;
+	ua->playback.buffer_pos = 0;
+	return 0;
+}
+
+static int capture_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct ua101 *ua = substream->private_data;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		if (!test_bit(USB_CAPTURE_RUNNING, &ua->states))
+			return -EIO;
+		set_bit(ALSA_CAPTURE_RUNNING, &ua->states);
+		return 0;
+	case SNDRV_PCM_TRIGGER_STOP:
+		clear_bit(ALSA_CAPTURE_RUNNING, &ua->states);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int playback_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct ua101 *ua = substream->private_data;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		if (!test_bit(USB_PLAYBACK_RUNNING, &ua->states))
+			return -EIO;
+		set_bit(ALSA_PLAYBACK_RUNNING, &ua->states);
+		return 0;
+	case SNDRV_PCM_TRIGGER_STOP:
+		clear_bit(ALSA_PLAYBACK_RUNNING, &ua->states);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static inline snd_pcm_uframes_t ua101_pcm_pointer(struct ua101 *ua,
+						  struct ua101_stream *stream)
+{
+	guard(spinlock_irqsave)(&ua->lock);
+	return stream->buffer_pos;
+}
+
+static snd_pcm_uframes_t capture_pcm_pointer(struct snd_pcm_substream *subs)
+{
+	struct ua101 *ua = subs->private_data;
+
+	return ua101_pcm_pointer(ua, &ua->capture);
+}
+
+static snd_pcm_uframes_t playback_pcm_pointer(struct snd_pcm_substream *subs)
+{
+	struct ua101 *ua = subs->private_data;
+
+	return ua101_pcm_pointer(ua, &ua->playback);
+}
+
+static const struct snd_pcm_ops capture_pcm_ops = {
+	.open = capture_pcm_open,
+	.close = capture_pcm_close,
+	.hw_params = capture_pcm_hw_params,
+	.prepare = capture_pcm_prepare,
+	.trigger = capture_pcm_trigger,
+	.pointer = capture_pcm_pointer,
+};
+
+static const struct snd_pcm_ops playback_pcm_ops = {
+	.open = playback_pcm_open,
+	.close = playback_pcm_close,
+	.hw_params = playback_pcm_hw_params,
+	.prepare = playback_pcm_prepare,
+	.trigger = playback_pcm_trigger,
+	.pointer = playback_pcm_pointer,
+};
+
+static const struct uac_format_type_i_discrete_descriptor *
+find_format_descriptor(struct usb_interface *interface)
+{
+	struct usb_host_interface *alt;
+	u8 *extra;
+	int extralen;
+
+	if (interface->num_altsetting != 2) {
+		dev_err(&interface->dev, "invalid num_altsetting\n");
+		return NULL;
+	}
+
+	alt = &interface->altsetting[0];
+	if (alt->desc.bNumEndpoints != 0) {
+		dev_err(&interface->dev, "invalid bNumEndpoints\n");
+		return NULL;
+	}
+
+	alt = &interface->altsetting[1];
+	if (alt->desc.bNumEndpoints != 1) {
+		dev_err(&interface->dev, "invalid bNumEndpoints\n");
+		return NULL;
+	}
+
+	extra = alt->extra;
+	extralen = alt->extralen;
+	while (extralen >= sizeof(struct usb_descriptor_header)) {
+		struct uac_format_type_i_discrete_descriptor *desc;
+
+		desc = (struct uac_format_type_i_discrete_descriptor *)extra;
+		if (desc->bLength < sizeof(struct usb_descriptor_header) ||
+		    desc->bLength > extralen) {
+			dev_err(&interface->dev, "invalid descriptor length\n");
+			return NULL;
+		}
+		if (desc->bLength == UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1) &&
+		    desc->bDescriptorType == USB_DT_CS_INTERFACE &&
+		    desc->bDescriptorSubtype == UAC_FORMAT_TYPE) {
+			if (desc->bFormatType != UAC_FORMAT_TYPE_I_PCM ||
+			    desc->bSamFreqType != 1) {
+				dev_err(&interface->dev,
+					"invalid format type\n");
+				return NULL;
+			}
+			return desc;
+		}
+		extralen -= desc->bLength;
+		extra += desc->bLength;
+	}
+	dev_err(&interface->dev, "sample format descriptor not found\n");
+	return NULL;
+}
+
+static int detect_usb_format(struct ua101 *ua)
+{
+	const struct uac_format_type_i_discrete_descriptor *fmt_capture;
+	const struct uac_format_type_i_discrete_descriptor *fmt_playback;
+	const struct usb_endpoint_descriptor *epd;
+	unsigned int rate2;
+
+	fmt_capture = find_format_descriptor(ua->intf[INTF_CAPTURE]);
+	fmt_playback = find_format_descriptor(ua->intf[INTF_PLAYBACK]);
+	if (!fmt_capture || !fmt_playback)
+		return -ENXIO;
+
+	switch (fmt_capture->bSubframeSize) {
+	case 3:
+		ua->format_bit = SNDRV_PCM_FMTBIT_S24_3LE;
+		break;
+	case 4:
+		ua->format_bit = SNDRV_PCM_FMTBIT_S32_LE;
+		break;
+	default:
+		dev_err(&ua->dev->dev, "sample width is not 24 or 32 bits\n");
+		return -ENXIO;
+	}
+	if (fmt_capture->bSubframeSize != fmt_playback->bSubframeSize) {
+		dev_err(&ua->dev->dev,
+			"playback/capture sample widths do not match\n");
+		return -ENXIO;
+	}
+
+	if (fmt_capture->bBitResolution != 24 ||
+	    fmt_playback->bBitResolution != 24) {
+		dev_err(&ua->dev->dev, "sample width is not 24 bits\n");
+		return -ENXIO;
+	}
+
+	ua->rate = combine_triple(fmt_capture->tSamFreq[0]);
+	rate2 = combine_triple(fmt_playback->tSamFreq[0]);
+	if (ua->rate != rate2) {
+		dev_err(&ua->dev->dev,
+			"playback/capture rates do not match: %u/%u\n",
+			rate2, ua->rate);
+		return -ENXIO;
+	}
+
+	switch (ua->dev->speed) {
+	case USB_SPEED_FULL:
+		ua->packets_per_second = 1000;
+		break;
+	case USB_SPEED_HIGH:
+		ua->packets_per_second = 8000;
+		break;
+	default:
+		dev_err(&ua->dev->dev, "unknown device speed\n");
+		return -ENXIO;
+	}
+
+	ua->capture.channels = fmt_capture->bNrChannels;
+	ua->playback.channels = fmt_playback->bNrChannels;
+	if (!ua->capture.channels || !ua->playback.channels) {
+		dev_err(&ua->dev->dev,
+			"invalid channel count: capture %u, playback %u\n",
+			ua->capture.channels, ua->playback.channels);
+		return -EINVAL;
+	}
+
+	ua->capture.frame_bytes =
+		fmt_capture->bSubframeSize * ua->capture.channels;
+	ua->playback.frame_bytes =
+		fmt_playback->bSubframeSize * ua->playback.channels;
+
+	epd = &ua->intf[INTF_CAPTURE]->altsetting[1].endpoint[0].desc;
+	if (!usb_endpoint_is_isoc_in(epd) || usb_endpoint_maxp(epd) == 0) {
+		dev_err(&ua->dev->dev, "invalid capture endpoint\n");
+		return -ENXIO;
+	}
+	ua->capture.usb_pipe = usb_rcvisocpipe(ua->dev, usb_endpoint_num(epd));
+	ua->capture.max_packet_bytes = usb_endpoint_maxp(epd);
+
+	epd = &ua->intf[INTF_PLAYBACK]->altsetting[1].endpoint[0].desc;
+	if (!usb_endpoint_is_isoc_out(epd) || usb_endpoint_maxp(epd) == 0) {
+		dev_err(&ua->dev->dev, "invalid playback endpoint\n");
+		return -ENXIO;
+	}
+	ua->playback.usb_pipe = usb_sndisocpipe(ua->dev, usb_endpoint_num(epd));
+	ua->playback.max_packet_bytes = usb_endpoint_maxp(epd);
+
+	if (ua->capture.max_packet_bytes / ua->capture.frame_bytes *
+	    ua->playback.frame_bytes > ua->playback.max_packet_bytes) {
+		dev_err(&ua->dev->dev,
+			"playback packet size %u too small for %u capture frames\n",
+			ua->playback.max_packet_bytes,
+			ua->capture.max_packet_bytes / ua->capture.frame_bytes);
+		return -ENXIO;
+	}
+	return 0;
+}
+
+static int alloc_stream_buffers(struct ua101 *ua, struct ua101_stream *stream)
+{
+	unsigned int remaining_packets, packets, packets_per_page, i;
+	size_t size;
+
+	stream->queue_length = queue_length;
+	stream->queue_length = max(stream->queue_length,
+				   (unsigned int)MIN_QUEUE_LENGTH);
+	stream->queue_length = min(stream->queue_length,
+				   (unsigned int)MAX_QUEUE_LENGTH);
+
+	/*
+	 * The cache pool sizes used by usb_alloc_coherent() (128, 512, 2048) are
+	 * quite bad when used with the packet sizes of this device (e.g. 280,
+	 * 520, 624).  Therefore, we allocate and subdivide entire pages, using
+	 * a smaller buffer only for the last chunk.
+	 */
+	remaining_packets = stream->queue_length;
+	packets_per_page = PAGE_SIZE / stream->max_packet_bytes;
+	for (i = 0; i < ARRAY_SIZE(stream->buffers); ++i) {
+		packets = min(remaining_packets, packets_per_page);
+		size = packets * stream->max_packet_bytes;
+		stream->buffers[i].addr =
+			usb_alloc_coherent(ua->dev, size, GFP_KERNEL,
+					   &stream->buffers[i].dma);
+		if (!stream->buffers[i].addr)
+			return -ENOMEM;
+		stream->buffers[i].size = size;
+		remaining_packets -= packets;
+		if (!remaining_packets)
+			break;
+	}
+	if (remaining_packets) {
+		dev_err(&ua->dev->dev, "too many packets\n");
+		return -ENXIO;
+	}
+	return 0;
+}
+
+static void free_stream_buffers(struct ua101 *ua, struct ua101_stream *stream)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(stream->buffers); ++i)
+		usb_free_coherent(ua->dev,
+				  stream->buffers[i].size,
+				  stream->buffers[i].addr,
+				  stream->buffers[i].dma);
+}
+
+static int alloc_stream_urbs(struct ua101 *ua, struct ua101_stream *stream,
+			     void (*urb_complete)(struct urb *))
+{
+	unsigned max_packet_size = stream->max_packet_bytes;
+	struct urb *urb;
+	unsigned int b, u = 0;
+
+	for (b = 0; b < ARRAY_SIZE(stream->buffers); ++b) {
+		unsigned int size = stream->buffers[b].size;
+		u8 *addr = stream->buffers[b].addr;
+		dma_addr_t dma = stream->buffers[b].dma;
+
+		while (size >= max_packet_size) {
+			if (u >= stream->queue_length)
+				goto bufsize_error;
+			urb = usb_alloc_urb(1, GFP_KERNEL);
+			if (!urb)
+				return -ENOMEM;
+			urb->dev = ua->dev;
+			urb->pipe = stream->usb_pipe;
+			urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+			urb->transfer_buffer = addr;
+			urb->transfer_dma = dma;
+			urb->transfer_buffer_length = max_packet_size;
+			urb->number_of_packets = 1;
+			urb->interval = 1;
+			urb->context = &stream->urbs[u];
+			urb->complete = urb_complete;
+			urb->iso_frame_desc[0].offset = 0;
+			urb->iso_frame_desc[0].length = max_packet_size;
+			stream->urbs[u].ua = ua;
+			stream->urbs[u].urb = urb;
+			u++;
+			size -= max_packet_size;
+			addr += max_packet_size;
+			dma += max_packet_size;
+		}
+	}
+	if (u == stream->queue_length)
+		return 0;
+bufsize_error:
+	dev_err(&ua->dev->dev, "internal buffer size error\n");
+	return -ENXIO;
+}
+
+static void free_stream_urbs(struct ua101_stream *stream)
+{
+	unsigned int i;
+
+	for (i = 0; i < stream->queue_length; ++i) {
+		usb_free_urb(stream->urbs[i].urb);
+		stream->urbs[i].urb = NULL;
+	}
+}
+
+static void free_usb_related_resources(struct ua101 *ua,
+				       struct usb_interface *interface)
+{
+	unsigned int i;
+	struct usb_interface *intf;
+
+	scoped_guard(mutex, &ua->mutex) {
+		free_stream_urbs(&ua->capture);
+		free_stream_urbs(&ua->playback);
+	}
+	free_stream_buffers(ua, &ua->capture);
+	free_stream_buffers(ua, &ua->playback);
+
+	for (i = 0; i < ARRAY_SIZE(ua->intf); ++i) {
+		scoped_guard(mutex, &ua->mutex) {
+			intf = ua->intf[i];
+			ua->intf[i] = NULL;
+		}
+		if (intf) {
+			usb_set_intfdata(intf, NULL);
+			if (intf != interface)
+				usb_driver_release_interface(&ua101_driver,
+							     intf);
+		}
+	}
+}
+
+static void ua101_card_free(struct snd_card *card)
+{
+	struct ua101 *ua = card->private_data;
+
+	mutex_destroy(&ua->mutex);
+}
+
+static int ua101_probe(struct usb_interface *interface,
+		       const struct usb_device_id *usb_id)
+{
+	static const struct snd_usb_midi_endpoint_info midi_ep = {
+		.out_cables = 0x0001,
+		.in_cables = 0x0001
+	};
+	static const struct snd_usb_audio_quirk midi_quirk = {
+		.type = QUIRK_MIDI_FIXED_ENDPOINT,
+		.data = &midi_ep
+	};
+	static const int intf_numbers[2][3] = {
+		{	/* UA-101 */
+			[INTF_PLAYBACK] = 0,
+			[INTF_CAPTURE] = 1,
+			[INTF_MIDI] = 2,
+		},
+		{	/* UA-1000 */
+			[INTF_CAPTURE] = 1,
+			[INTF_PLAYBACK] = 2,
+			[INTF_MIDI] = 3,
+		},
+	};
+	struct snd_card *card;
+	struct ua101 *ua;
+	unsigned int card_index, i;
+	int is_ua1000;
+	const char *name;
+	char usb_path[32];
+	int err;
+
+	is_ua1000 = usb_id->idProduct == 0x0044;
+
+	if (interface->altsetting->desc.bInterfaceNumber !=
+	    intf_numbers[is_ua1000][0])
+		return -ENODEV;
+
+	guard(mutex)(&devices_mutex);
+
+	for (card_index = 0; card_index < SNDRV_CARDS; ++card_index)
+		if (enable[card_index] && !(devices_used & (1 << card_index)))
+			break;
+	if (card_index >= SNDRV_CARDS)
+		return -ENOENT;
+	err = snd_card_new(&interface->dev,
+			   index[card_index], id[card_index], THIS_MODULE,
+			   sizeof(*ua), &card);
+	if (err < 0)
+		return err;
+	card->private_free = ua101_card_free;
+	ua = card->private_data;
+	ua->dev = interface_to_usbdev(interface);
+	ua->card = card;
+	ua->card_index = card_index;
+	INIT_LIST_HEAD(&ua->midi_list);
+	spin_lock_init(&ua->lock);
+	mutex_init(&ua->mutex);
+	INIT_LIST_HEAD(&ua->ready_playback_urbs);
+	INIT_WORK(&ua->playback_work, playback_work);
+	init_waitqueue_head(&ua->alsa_capture_wait);
+	init_waitqueue_head(&ua->rate_feedback_wait);
+	init_waitqueue_head(&ua->alsa_playback_wait);
+
+	ua->intf[0] = interface;
+	for (i = 1; i < ARRAY_SIZE(ua->intf); ++i) {
+		ua->intf[i] = usb_ifnum_to_if(ua->dev,
+					      intf_numbers[is_ua1000][i]);
+		if (!ua->intf[i]) {
+			dev_err(&ua->dev->dev, "interface %u not found\n",
+				intf_numbers[is_ua1000][i]);
+			err = -ENXIO;
+			goto probe_error;
+		}
+		err = usb_driver_claim_interface(&ua101_driver,
+						 ua->intf[i], ua);
+		if (err < 0) {
+			ua->intf[i] = NULL;
+			err = -EBUSY;
+			goto probe_error;
+		}
+	}
+
+	err = detect_usb_format(ua);
+	if (err < 0)
+		goto probe_error;
+
+	name = usb_id->idProduct == 0x0044 ? "UA-1000" : "UA-101";
+	strscpy(card->driver, "UA-101");
+	strscpy(card->shortname, name);
+	usb_make_path(ua->dev, usb_path, sizeof(usb_path));
+	snprintf(ua->card->longname, sizeof(ua->card->longname),
+		 "EDIROL %s (serial %s), %u Hz at %s, %s speed", name,
+		 ua->dev->serial ? ua->dev->serial : "?", ua->rate, usb_path,
+		 ua->dev->speed == USB_SPEED_HIGH ? "high" : "full");
+
+	err = alloc_stream_buffers(ua, &ua->capture);
+	if (err < 0)
+		goto probe_error;
+	err = alloc_stream_buffers(ua, &ua->playback);
+	if (err < 0)
+		goto probe_error;
+
+	err = alloc_stream_urbs(ua, &ua->capture, capture_urb_complete);
+	if (err < 0)
+		goto probe_error;
+	err = alloc_stream_urbs(ua, &ua->playback, playback_urb_complete);
+	if (err < 0)
+		goto probe_error;
+
+	err = snd_pcm_new(card, name, 0, 1, 1, &ua->pcm);
+	if (err < 0)
+		goto probe_error;
+	ua->pcm->private_data = ua;
+	strscpy(ua->pcm->name, name);
+	snd_pcm_set_ops(ua->pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_pcm_ops);
+	snd_pcm_set_ops(ua->pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_pcm_ops);
+	snd_pcm_set_managed_buffer_all(ua->pcm, SNDRV_DMA_TYPE_VMALLOC,
+				       NULL, 0, 0);
+
+	err = snd_usbmidi_create(card, ua->intf[INTF_MIDI],
+				 &ua->midi_list, &midi_quirk);
+	if (err < 0)
+		goto probe_error;
+
+	err = snd_card_register(card);
+	if (err < 0)
+		goto probe_error;
+
+	usb_set_intfdata(interface, ua);
+	devices_used |= 1 << card_index;
+
+	return 0;
+
+probe_error:
+	free_usb_related_resources(ua, interface);
+	snd_card_free(card);
+	return err;
+}
+
+static void ua101_disconnect(struct usb_interface *interface)
+{
+	struct ua101 *ua = usb_get_intfdata(interface);
+	struct list_head *midi;
+
+	if (!ua)
+		return;
+
+	guard(mutex)(&devices_mutex);
+
+	set_bit(DISCONNECTED, &ua->states);
+	wake_up(&ua->rate_feedback_wait);
+
+	/* make sure that userspace cannot create new requests */
+	snd_card_disconnect(ua->card);
+
+	/* make sure that there are no pending USB requests */
+	list_for_each(midi, &ua->midi_list)
+		snd_usbmidi_disconnect(midi);
+	abort_alsa_playback(ua);
+	abort_alsa_capture(ua);
+	scoped_guard(mutex, &ua->mutex) {
+		stop_usb_playback(ua);
+		stop_usb_capture(ua);
+	}
+
+	free_usb_related_resources(ua, interface);
+
+	devices_used &= ~(1 << ua->card_index);
+
+	snd_card_free_when_closed(ua->card);
+}
+
+static const struct usb_device_id ua101_ids[] = {
+	{ USB_DEVICE(0x0582, 0x0044) }, /* UA-1000 high speed */
+	{ USB_DEVICE(0x0582, 0x007d) }, /* UA-101 high speed */
+	{ USB_DEVICE(0x0582, 0x008d) }, /* UA-101 full speed */
+	{ }
+};
+MODULE_DEVICE_TABLE(usb, ua101_ids);
+
+static struct usb_driver ua101_driver = {
+	.name = "snd-ua101",
+	.id_table = ua101_ids,
+	.probe = ua101_probe,
+	.disconnect = ua101_disconnect,
+#if 0
+	.suspend = ua101_suspend,
+	.resume = ua101_resume,
+#endif
+};
+
+module_usb_driver(ua101_driver);
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
new file mode 100644
index 000000000..ecaa8bc08
--- /dev/null
+++ b/sound/usb/mixer.c
@@ -0,0 +1,3942 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   (Tentative) USB Audio Driver for ALSA
+ *
+ *   Mixer control part
+ *
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
+ *
+ *   Many codes borrowed from audio.c by
+ *	    Alan Cox (alan@lxorguk.ukuu.org.uk)
+ *	    Thomas Sailer (sailer@ife.ee.ethz.ch)
+ */
+
+/*
+ * TODOs, for both the mixer and the streaming interfaces:
+ *
+ *  - support for UAC2 effect units
+ *  - support for graphical equalizers
+ *  - RANGE and MEM set commands (UAC2)
+ *  - RANGE and MEM interrupt dispatchers (UAC2)
+ *  - audio channel clustering (UAC2)
+ *  - audio sample rate converter units (UAC2)
+ *  - proper handling of clock multipliers (UAC2)
+ *  - dispatch clock change notifications (UAC2)
+ *  	- stop PCM streams which use a clock that became invalid
+ *  	- stop PCM streams which use a clock selector that has changed
+ *  	- parse available sample rates again when clock sources changed
+ */
+
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/log2.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/hwdep.h>
+#include <sound/info.h>
+#include <sound/tlv.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "helper.h"
+#include "mixer_quirks.h"
+#include "power.h"
+
+#define MAX_ID_ELEMS	256
+
+struct usb_audio_term {
+	int id;
+	int type;
+	int channels;
+	unsigned int chconfig;
+	int name;
+};
+
+struct usbmix_name_map;
+
+struct mixer_build {
+	struct snd_usb_audio *chip;
+	struct usb_mixer_interface *mixer;
+	unsigned char *buffer;
+	unsigned int buflen;
+	DECLARE_BITMAP(unitbitmap, MAX_ID_ELEMS);
+	DECLARE_BITMAP(termbitmap, MAX_ID_ELEMS);
+	struct usb_audio_term oterm;
+	const struct usbmix_name_map *map;
+	const struct usbmix_selector_map *selector_map;
+};
+
+/*E-mu 0202/0404/0204 eXtension Unit(XU) control*/
+enum {
+	USB_XU_CLOCK_RATE 		= 0xe301,
+	USB_XU_CLOCK_SOURCE		= 0xe302,
+	USB_XU_DIGITAL_IO_STATUS	= 0xe303,
+	USB_XU_DEVICE_OPTIONS		= 0xe304,
+	USB_XU_DIRECT_MONITORING	= 0xe305,
+	USB_XU_METERING			= 0xe306
+};
+enum {
+	USB_XU_CLOCK_SOURCE_SELECTOR = 0x02,	/* clock source*/
+	USB_XU_CLOCK_RATE_SELECTOR = 0x03,	/* clock rate */
+	USB_XU_DIGITAL_FORMAT_SELECTOR = 0x01,	/* the spdif format */
+	USB_XU_SOFT_LIMIT_SELECTOR = 0x03	/* soft limiter */
+};
+
+/*
+ * manual mapping of mixer names
+ * if the mixer topology is too complicated and the parsed names are
+ * ambiguous, add the entries in usbmixer_maps.c.
+ */
+#include "mixer_maps.c"
+
+static const struct usbmix_name_map *
+find_map(const struct usbmix_name_map *p, int unitid, int control)
+{
+	if (!p)
+		return NULL;
+
+	for (; p->id; p++) {
+		if (p->id == unitid &&
+		    (!control || !p->control || control == p->control))
+			return p;
+	}
+	return NULL;
+}
+
+/* get the mapped name if the unit matches */
+static int
+check_mapped_name(const struct usbmix_name_map *p, char *buf, int buflen)
+{
+	int len;
+
+	if (!p || !p->name)
+		return 0;
+
+	buflen--;
+	len = strscpy(buf, p->name, buflen);
+	return len < 0 ? buflen : len;
+}
+
+/* ignore the error value if ignore_ctl_error flag is set */
+#define filter_error(cval, err) \
+	((cval)->head.mixer->ignore_ctl_error ? 0 : (err))
+
+/* check whether the control should be ignored */
+static inline int
+check_ignored_ctl(const struct usbmix_name_map *p)
+{
+	if (!p || p->name || p->dB)
+		return 0;
+	return 1;
+}
+
+/* dB mapping */
+static inline void check_mapped_dB(const struct usbmix_name_map *p,
+				   struct usb_mixer_elem_info *cval)
+{
+	if (p && p->dB) {
+		cval->dBmin = p->dB->min;
+		cval->dBmax = p->dB->max;
+		cval->min_mute = p->dB->min_mute;
+		cval->initialized = 1;
+	}
+}
+
+/* get the mapped selector source name */
+static int check_mapped_selector_name(struct mixer_build *state, int unitid,
+				      int index, char *buf, int buflen)
+{
+	const struct usbmix_selector_map *p;
+	int len;
+
+	if (!state->selector_map)
+		return 0;
+	for (p = state->selector_map; p->id; p++) {
+		if (p->id == unitid && index < p->count) {
+			len = strscpy(buf, p->names[index], buflen);
+			return len < 0 ? buflen : len;
+		}
+	}
+	return 0;
+}
+
+/*
+ * find an audio control unit with the given unit id
+ */
+static void *find_audio_control_unit(struct mixer_build *state,
+				     unsigned char unit)
+{
+	/* we just parse the header */
+	struct uac_feature_unit_descriptor *hdr = NULL;
+
+	while ((hdr = snd_usb_find_desc(state->buffer, state->buflen, hdr,
+					USB_DT_CS_INTERFACE)) != NULL) {
+		if (hdr->bLength >= 4 &&
+		    hdr->bDescriptorSubtype >= UAC_INPUT_TERMINAL &&
+		    hdr->bDescriptorSubtype <= UAC3_SAMPLE_RATE_CONVERTER &&
+		    hdr->bUnitID == unit)
+			return hdr;
+	}
+
+	return NULL;
+}
+
+/*
+ * copy a string with the given id
+ */
+static int snd_usb_copy_string_desc(struct snd_usb_audio *chip,
+				    int index, char *buf, int maxlen)
+{
+	int len = usb_string(chip->dev, index, buf, maxlen - 1);
+
+	if (len < 0)
+		return 0;
+
+	buf[len] = 0;
+	return len;
+}
+
+/*
+ * convert from the byte/word on usb descriptor to the zero-based integer
+ */
+static int convert_signed_value(struct usb_mixer_elem_info *cval, int val)
+{
+	switch (cval->val_type) {
+	case USB_MIXER_BOOLEAN:
+		return !!val;
+	case USB_MIXER_INV_BOOLEAN:
+		return !val;
+	case USB_MIXER_U8:
+		val &= 0xff;
+		break;
+	case USB_MIXER_S8:
+		val &= 0xff;
+		if (val >= 0x80)
+			val -= 0x100;
+		break;
+	case USB_MIXER_U16:
+		val &= 0xffff;
+		break;
+	case USB_MIXER_S16:
+		val &= 0xffff;
+		if (val >= 0x8000)
+			val -= 0x10000;
+		break;
+	}
+	return val;
+}
+
+/*
+ * convert from the zero-based int to the byte/word for usb descriptor
+ */
+static int convert_bytes_value(struct usb_mixer_elem_info *cval, int val)
+{
+	switch (cval->val_type) {
+	case USB_MIXER_BOOLEAN:
+		return !!val;
+	case USB_MIXER_INV_BOOLEAN:
+		return !val;
+	case USB_MIXER_S8:
+	case USB_MIXER_U8:
+		return val & 0xff;
+	case USB_MIXER_S16:
+	case USB_MIXER_U16:
+		return val & 0xffff;
+	}
+	return 0; /* not reached */
+}
+
+static int get_relative_value(struct usb_mixer_elem_info *cval, int val)
+{
+	if (!cval->res)
+		cval->res = 1;
+	if (val < cval->min)
+		return 0;
+	else if (val >= cval->max)
+		return DIV_ROUND_UP(cval->max - cval->min, cval->res);
+	else
+		return (val - cval->min) / cval->res;
+}
+
+static int get_abs_value(struct usb_mixer_elem_info *cval, int val)
+{
+	if (val < 0)
+		return cval->min;
+	if (!cval->res)
+		cval->res = 1;
+	val *= cval->res;
+	val += cval->min;
+	if (val > cval->max)
+		return cval->max;
+	return val;
+}
+
+static int uac2_ctl_value_size(int val_type)
+{
+	switch (val_type) {
+	case USB_MIXER_S32:
+	case USB_MIXER_U32:
+		return 4;
+	case USB_MIXER_S16:
+	case USB_MIXER_U16:
+		return 2;
+	default:
+		return 1;
+	}
+	return 0; /* unreachable */
+}
+
+
+/*
+ * retrieve a mixer value
+ */
+
+static inline int mixer_ctrl_intf(struct usb_mixer_interface *mixer)
+{
+	return get_iface_desc(mixer->hostif)->bInterfaceNumber;
+}
+
+static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request,
+			    int validx, int *value_ret)
+{
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+	unsigned char buf[2];
+	int val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
+	int timeout = 10;
+	int idx = 0, err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	while (timeout-- > 0) {
+		idx = mixer_ctrl_intf(cval->head.mixer) | (cval->head.id << 8);
+		err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), request,
+				      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+				      validx, idx, buf, val_len);
+		if (err >= val_len) {
+			*value_ret = convert_signed_value(cval, snd_usb_combine_bytes(buf, val_len));
+			return 0;
+		} else if (err == -ETIMEDOUT) {
+			return err;
+		}
+	}
+	usb_audio_dbg(chip,
+		"cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
+		request, validx, idx, cval->val_type);
+	return -EINVAL;
+}
+
+static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request,
+			    int validx, int *value_ret)
+{
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+	/* enough space for one range */
+	unsigned char buf[sizeof(__u16) + 3 * sizeof(__u32)];
+	unsigned char *val;
+	int idx = 0, ret, val_size, size;
+	__u8 bRequest;
+
+	val_size = uac2_ctl_value_size(cval->val_type);
+
+	if (request == UAC_GET_CUR) {
+		bRequest = UAC2_CS_CUR;
+		size = val_size;
+	} else {
+		bRequest = UAC2_CS_RANGE;
+		size = sizeof(__u16) + 3 * val_size;
+	}
+
+	memset(buf, 0, sizeof(buf));
+
+	{
+		CLASS(snd_usb_lock, pm)(chip);
+		if (pm.err)
+			return -EIO;
+
+		idx = mixer_ctrl_intf(cval->head.mixer) | (cval->head.id << 8);
+		ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), bRequest,
+				      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+				      validx, idx, buf, size);
+	}
+
+	if (ret < 0) {
+		usb_audio_dbg(chip,
+			"cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
+			request, validx, idx, cval->val_type);
+		return ret;
+	}
+
+	/* FIXME: how should we handle multiple triplets here? */
+
+	switch (request) {
+	case UAC_GET_CUR:
+		val = buf;
+		break;
+	case UAC_GET_MIN:
+		val = buf + sizeof(__u16);
+		break;
+	case UAC_GET_MAX:
+		val = buf + sizeof(__u16) + val_size;
+		break;
+	case UAC_GET_RES:
+		val = buf + sizeof(__u16) + val_size * 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	*value_ret = convert_signed_value(cval,
+					  snd_usb_combine_bytes(val, val_size));
+
+	return 0;
+}
+
+static int get_ctl_value(struct usb_mixer_elem_info *cval, int request,
+			 int validx, int *value_ret)
+{
+	validx += cval->idx_off;
+
+	return (cval->head.mixer->protocol == UAC_VERSION_1) ?
+		get_ctl_value_v1(cval, request, validx, value_ret) :
+		get_ctl_value_v2(cval, request, validx, value_ret);
+}
+
+static int get_cur_ctl_value(struct usb_mixer_elem_info *cval,
+			     int validx, int *value)
+{
+	return get_ctl_value(cval, UAC_GET_CUR, validx, value);
+}
+
+/* channel = 0: master, 1 = first channel */
+static inline int get_cur_mix_raw(struct usb_mixer_elem_info *cval,
+				  int channel, int *value)
+{
+	return get_ctl_value(cval, UAC_GET_CUR,
+			     (cval->control << 8) | channel,
+			     value);
+}
+
+int snd_usb_get_cur_mix_value(struct usb_mixer_elem_info *cval,
+			     int channel, int index, int *value)
+{
+	int err;
+
+	if (cval->cached & BIT(channel)) {
+		*value = cval->cache_val[index];
+		return 0;
+	}
+
+	/* The current value is always provided by the cache after initialization. */
+	if (cval->get_cur_broken)
+		return -ENXIO;
+
+	err = get_cur_mix_raw(cval, channel, value);
+	if (err < 0) {
+		if (!cval->head.mixer->ignore_ctl_error)
+			usb_audio_dbg(cval->head.mixer->chip,
+				"cannot get current value for control %d ch %d: err = %d\n",
+				      cval->control, channel, err);
+		return err;
+	}
+	cval->cached |= BIT(channel);
+	cval->cache_val[index] = *value;
+	return 0;
+}
+
+/*
+ * set a mixer value
+ */
+
+int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
+				int request, int validx, int value_set)
+{
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+	unsigned char buf[4];
+	int idx = 0, val_len, err, timeout = 10;
+
+	validx += cval->idx_off;
+
+
+	if (cval->head.mixer->protocol == UAC_VERSION_1) {
+		val_len = cval->val_type >= USB_MIXER_S16 ? 2 : 1;
+	} else { /* UAC_VERSION_2/3 */
+		val_len = uac2_ctl_value_size(cval->val_type);
+
+		/* FIXME */
+		if (request != UAC_SET_CUR) {
+			usb_audio_dbg(chip, "RANGE setting not yet supported\n");
+			return -EINVAL;
+		}
+
+		request = UAC2_CS_CUR;
+	}
+
+	value_set = convert_bytes_value(cval, value_set);
+	buf[0] = value_set & 0xff;
+	buf[1] = (value_set >> 8) & 0xff;
+	buf[2] = (value_set >> 16) & 0xff;
+	buf[3] = (value_set >> 24) & 0xff;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	while (timeout-- > 0) {
+		idx = mixer_ctrl_intf(cval->head.mixer) | (cval->head.id << 8);
+		err = snd_usb_ctl_msg(chip->dev,
+				      usb_sndctrlpipe(chip->dev, 0), request,
+				      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+				      validx, idx, buf, val_len);
+		if (err >= 0)
+			return 0;
+		else if (err == -ETIMEDOUT)
+			return err;
+	}
+	usb_audio_dbg(chip, "cannot set ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d, data = %#x/%#x\n",
+		      request, validx, idx, cval->val_type, buf[0], buf[1]);
+	return -EINVAL;
+}
+
+static int set_cur_ctl_value(struct usb_mixer_elem_info *cval,
+			     int validx, int value)
+{
+	return snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR, validx, value);
+}
+
+int snd_usb_set_cur_mix_value(struct usb_mixer_elem_info *cval, int channel,
+			     int index, int value)
+{
+	int err;
+	unsigned int read_only = (channel == 0) ?
+		cval->master_readonly :
+		cval->ch_readonly & BIT(channel - 1);
+
+	if (read_only) {
+		usb_audio_dbg(cval->head.mixer->chip,
+			      "%s(): channel %d of control %d is read_only\n",
+			    __func__, channel, cval->control);
+		return 0;
+	}
+
+	err = snd_usb_mixer_set_ctl_value(cval,
+					  UAC_SET_CUR, (cval->control << 8) | channel,
+					  value);
+	if (err < 0)
+		return err;
+	cval->cached |= BIT(channel);
+	cval->cache_val[index] = value;
+	return 0;
+}
+
+/*
+ * TLV callback for mixer volume controls
+ */
+int snd_usb_mixer_vol_tlv(struct snd_kcontrol *kcontrol, int op_flag,
+			 unsigned int size, unsigned int __user *_tlv)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	DECLARE_TLV_DB_MINMAX(scale, 0, 0);
+
+	if (size < sizeof(scale))
+		return -ENOMEM;
+	if (cval->min_mute)
+		scale[0] = SNDRV_CTL_TLVT_DB_MINMAX_MUTE;
+	scale[2] = cval->dBmin;
+	scale[3] = cval->dBmax;
+	if (copy_to_user(_tlv, scale, sizeof(scale)))
+		return -EFAULT;
+	return 0;
+}
+
+/*
+ * parser routines begin here...
+ */
+
+static int parse_audio_unit(struct mixer_build *state, int unitid);
+
+
+/*
+ * check if the input/output channel routing is enabled on the given bitmap.
+ * used for mixer unit parser
+ */
+static int check_matrix_bitmap(unsigned char *bmap,
+			       int ich, int och, int num_outs)
+{
+	int idx = ich * num_outs + och;
+	return bmap[idx >> 3] & (0x80 >> (idx & 7));
+}
+
+/*
+ * add an alsa control element
+ * search and increment the index until an empty slot is found.
+ *
+ * if failed, give up and free the control instance.
+ */
+
+int snd_usb_mixer_add_list(struct usb_mixer_elem_list *list,
+			   struct snd_kcontrol *kctl,
+			   bool is_std_info)
+{
+	struct usb_mixer_interface *mixer = list->mixer;
+	int err;
+
+	while (snd_ctl_find_id(mixer->chip->card, &kctl->id))
+		kctl->id.index++;
+	err = snd_ctl_add(mixer->chip->card, kctl);
+	if (err < 0) {
+		usb_audio_dbg(mixer->chip, "cannot add control (err = %d)\n",
+			      err);
+		return err;
+	}
+	list->kctl = kctl;
+	list->is_std_info = is_std_info;
+	list->next_id_elem = mixer->id_elems[list->id];
+	mixer->id_elems[list->id] = list;
+	return 0;
+}
+
+/*
+ * get a terminal name string
+ */
+
+static struct iterm_name_combo {
+	int type;
+	char *name;
+} iterm_names[] = {
+	{ 0x0300, "Output" },
+	{ 0x0301, "Speaker" },
+	{ 0x0302, "Headphone" },
+	{ 0x0303, "HMD Audio" },
+	{ 0x0304, "Desktop Speaker" },
+	{ 0x0305, "Room Speaker" },
+	{ 0x0306, "Com Speaker" },
+	{ 0x0307, "LFE" },
+	{ 0x0600, "External In" },
+	{ 0x0601, "Analog In" },
+	{ 0x0602, "Digital In" },
+	{ 0x0603, "Line" },
+	{ 0x0604, "Legacy In" },
+	{ 0x0605, "IEC958 In" },
+	{ 0x0606, "1394 DA Stream" },
+	{ 0x0607, "1394 DV Stream" },
+	{ 0x0700, "Embedded" },
+	{ 0x0701, "Noise Source" },
+	{ 0x0702, "Equalization Noise" },
+	{ 0x0703, "CD" },
+	{ 0x0704, "DAT" },
+	{ 0x0705, "DCC" },
+	{ 0x0706, "MiniDisk" },
+	{ 0x0707, "Analog Tape" },
+	{ 0x0708, "Phonograph" },
+	{ 0x0709, "VCR Audio" },
+	{ 0x070a, "Video Disk Audio" },
+	{ 0x070b, "DVD Audio" },
+	{ 0x070c, "TV Tuner Audio" },
+	{ 0x070d, "Satellite Rec Audio" },
+	{ 0x070e, "Cable Tuner Audio" },
+	{ 0x070f, "DSS Audio" },
+	{ 0x0710, "Radio Receiver" },
+	{ 0x0711, "Radio Transmitter" },
+	{ 0x0712, "Multi-Track Recorder" },
+	{ 0x0713, "Synthesizer" },
+	{ 0 },
+};
+
+static int get_term_name(struct snd_usb_audio *chip, struct usb_audio_term *iterm,
+			 unsigned char *name, int maxlen, int term_only)
+{
+	struct iterm_name_combo *names;
+	int len;
+
+	if (iterm->name) {
+		len = snd_usb_copy_string_desc(chip, iterm->name,
+						name, maxlen);
+		if (len)
+			return len;
+	}
+
+	/* virtual type - not a real terminal */
+	if (iterm->type >> 16) {
+		if (term_only)
+			return 0;
+		switch (iterm->type >> 16) {
+		case UAC3_SELECTOR_UNIT:
+			return strscpy(name, "Selector", maxlen);
+		case UAC3_PROCESSING_UNIT:
+			return strscpy(name, "Process Unit", maxlen);
+		case UAC3_EXTENSION_UNIT:
+			return strscpy(name, "Ext Unit", maxlen);
+		case UAC3_MIXER_UNIT:
+			return strscpy(name, "Mixer", maxlen);
+		default:
+			return scnprintf(name, maxlen, "Unit %d", iterm->id);
+		}
+	}
+
+	switch (iterm->type & 0xff00) {
+	case 0x0100:
+		return strscpy(name, "PCM", maxlen);
+	case 0x0200:
+		return strscpy(name, "Mic", maxlen);
+	case 0x0400:
+		return strscpy(name, "Headset", maxlen);
+	case 0x0500:
+		return strscpy(name, "Phone", maxlen);
+	}
+
+	for (names = iterm_names; names->type; names++)
+		if (names->type == iterm->type)
+			return strscpy(name, names->name, maxlen);
+
+	return 0;
+}
+
+/*
+ * Get logical cluster information for UAC3 devices.
+ */
+static int get_cluster_channels_v3(struct mixer_build *state, unsigned int cluster_id)
+{
+	struct uac3_cluster_header_descriptor c_header;
+	int err;
+
+	err = snd_usb_ctl_msg(state->chip->dev,
+			usb_rcvctrlpipe(state->chip->dev, 0),
+			UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			cluster_id,
+			snd_usb_ctrl_intf(state->mixer->hostif),
+			&c_header, sizeof(c_header));
+	if (err < 0)
+		goto error;
+	if (err != sizeof(c_header)) {
+		err = -EIO;
+		goto error;
+	}
+
+	return c_header.bNrChannels;
+
+error:
+	usb_audio_err(state->chip, "cannot request logical cluster ID: %d (err: %d)\n", cluster_id, err);
+	return err;
+}
+
+/*
+ * Get number of channels for a Mixer Unit.
+ */
+static int uac_mixer_unit_get_channels(struct mixer_build *state,
+				       struct uac_mixer_unit_descriptor *desc)
+{
+	int mu_channels;
+
+	switch (state->mixer->protocol) {
+	case UAC_VERSION_1:
+	case UAC_VERSION_2:
+	default:
+		if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 1)
+			return 0; /* no bmControls -> skip */
+		mu_channels = uac_mixer_unit_bNrChannels(desc);
+		break;
+	case UAC_VERSION_3:
+		mu_channels = get_cluster_channels_v3(state,
+				uac3_mixer_unit_wClusterDescrID(desc));
+		break;
+	}
+
+	return mu_channels;
+}
+
+/*
+ * Parse Input Terminal Unit
+ */
+static int __check_input_term(struct mixer_build *state, int id,
+			      struct usb_audio_term *term);
+
+static int parse_term_uac1_iterm_unit(struct mixer_build *state,
+				      struct usb_audio_term *term,
+				      void *p1, int id)
+{
+	struct uac_input_terminal_descriptor *d = p1;
+
+	term->type = le16_to_cpu(d->wTerminalType);
+	term->channels = d->bNrChannels;
+	term->chconfig = le16_to_cpu(d->wChannelConfig);
+	term->name = d->iTerminal;
+	return 0;
+}
+
+static int parse_term_uac2_iterm_unit(struct mixer_build *state,
+				      struct usb_audio_term *term,
+				      void *p1, int id)
+{
+	struct uac2_input_terminal_descriptor *d = p1;
+	int err;
+
+	/* call recursively to verify the referenced clock entity */
+	err = __check_input_term(state, d->bCSourceID, term);
+	if (err < 0)
+		return err;
+
+	/* save input term properties after recursion,
+	 * to ensure they are not overriden by the recursion calls
+	 */
+	term->id = id;
+	term->type = le16_to_cpu(d->wTerminalType);
+	term->channels = d->bNrChannels;
+	term->chconfig = le32_to_cpu(d->bmChannelConfig);
+	term->name = d->iTerminal;
+	return 0;
+}
+
+static int parse_term_uac3_iterm_unit(struct mixer_build *state,
+				      struct usb_audio_term *term,
+				      void *p1, int id)
+{
+	struct uac3_input_terminal_descriptor *d = p1;
+	int err;
+
+	/* call recursively to verify the referenced clock entity */
+	err = __check_input_term(state, d->bCSourceID, term);
+	if (err < 0)
+		return err;
+
+	/* save input term properties after recursion,
+	 * to ensure they are not overriden by the recursion calls
+	 */
+	term->id = id;
+	term->type = le16_to_cpu(d->wTerminalType);
+
+	err = get_cluster_channels_v3(state, le16_to_cpu(d->wClusterDescrID));
+	if (err < 0)
+		return err;
+	term->channels = err;
+
+	/* REVISIT: UAC3 IT doesn't have channels cfg */
+	term->chconfig = 0;
+
+	term->name = le16_to_cpu(d->wTerminalDescrStr);
+	return 0;
+}
+
+static int parse_term_mixer_unit(struct mixer_build *state,
+				 struct usb_audio_term *term,
+				 void *p1, int id)
+{
+	struct uac_mixer_unit_descriptor *d = p1;
+	int protocol = state->mixer->protocol;
+	int err;
+
+	err = uac_mixer_unit_get_channels(state, d);
+	if (err <= 0)
+		return err;
+
+	term->type = UAC3_MIXER_UNIT << 16; /* virtual type */
+	term->channels = err;
+	if (protocol != UAC_VERSION_3) {
+		term->chconfig = uac_mixer_unit_wChannelConfig(d, protocol);
+		term->name = uac_mixer_unit_iMixer(d);
+	}
+	return 0;
+}
+
+static int parse_term_selector_unit(struct mixer_build *state,
+				    struct usb_audio_term *term,
+				    void *p1, int id)
+{
+	struct uac_selector_unit_descriptor *d = p1;
+	int err;
+
+	/* call recursively to retrieve the channel info */
+	err = __check_input_term(state, d->baSourceID[0], term);
+	if (err < 0)
+		return err;
+	term->type = UAC3_SELECTOR_UNIT << 16; /* virtual type */
+	term->id = id;
+	if (state->mixer->protocol != UAC_VERSION_3)
+		term->name = uac_selector_unit_iSelector(d);
+	return 0;
+}
+
+static int parse_term_proc_unit(struct mixer_build *state,
+				struct usb_audio_term *term,
+				void *p1, int id, int vtype)
+{
+	struct uac_processing_unit_descriptor *d = p1;
+	int protocol = state->mixer->protocol;
+	int err;
+
+	if (d->bNrInPins) {
+		/* call recursively to retrieve the channel info */
+		err = __check_input_term(state, d->baSourceID[0], term);
+		if (err < 0)
+			return err;
+	}
+
+	term->type = vtype << 16; /* virtual type */
+	term->id = id;
+
+	if (protocol == UAC_VERSION_3)
+		return 0;
+
+	if (!term->channels) {
+		term->channels = uac_processing_unit_bNrChannels(d);
+		term->chconfig = uac_processing_unit_wChannelConfig(d, protocol);
+	}
+	term->name = uac_processing_unit_iProcessing(d, protocol);
+	return 0;
+}
+
+static int parse_term_effect_unit(struct mixer_build *state,
+				  struct usb_audio_term *term,
+				  void *p1, int id)
+{
+	struct uac2_effect_unit_descriptor *d = p1;
+	int err;
+
+	err = __check_input_term(state, d->bSourceID, term);
+	if (err < 0)
+		return err;
+	term->type = UAC3_EFFECT_UNIT << 16; /* virtual type */
+	term->id = id;
+	return 0;
+}
+
+static int parse_term_uac2_clock_source(struct mixer_build *state,
+					struct usb_audio_term *term,
+					void *p1, int id)
+{
+	struct uac_clock_source_descriptor *d = p1;
+
+	term->type = UAC2_CLOCK_SOURCE << 16; /* virtual type */
+	term->id = id;
+	term->name = d->iClockSource;
+	return 0;
+}
+
+static int parse_term_uac3_clock_source(struct mixer_build *state,
+					struct usb_audio_term *term,
+					void *p1, int id)
+{
+	struct uac3_clock_source_descriptor *d = p1;
+
+	term->type = UAC3_CLOCK_SOURCE << 16; /* virtual type */
+	term->id = id;
+	term->name = le16_to_cpu(d->wClockSourceStr);
+	return 0;
+}
+
+#define PTYPE(a, b)	((a) << 8 | (b))
+
+/*
+ * parse the source unit recursively until it reaches to a terminal
+ * or a branched unit.
+ */
+static int __check_input_term(struct mixer_build *state, int id,
+			      struct usb_audio_term *term)
+{
+	int protocol = state->mixer->protocol;
+	void *p1;
+	unsigned char *hdr;
+
+	for (;;) {
+		/* a loop in the terminal chain? */
+		if (test_and_set_bit(id, state->termbitmap))
+			return -EINVAL;
+
+		p1 = find_audio_control_unit(state, id);
+		if (!p1)
+			break;
+		if (!snd_usb_validate_audio_desc(p1, protocol))
+			break; /* bad descriptor */
+
+		hdr = p1;
+		term->id = id;
+
+		switch (PTYPE(protocol, hdr[2])) {
+		case PTYPE(UAC_VERSION_1, UAC_FEATURE_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC_FEATURE_UNIT):
+		case PTYPE(UAC_VERSION_3, UAC3_FEATURE_UNIT): {
+			/* the header is the same for all versions */
+			struct uac_feature_unit_descriptor *d = p1;
+
+			id = d->bSourceID;
+			break; /* continue to parse */
+		}
+		case PTYPE(UAC_VERSION_1, UAC_INPUT_TERMINAL):
+			return parse_term_uac1_iterm_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_2, UAC_INPUT_TERMINAL):
+			return parse_term_uac2_iterm_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_3, UAC_INPUT_TERMINAL):
+			return parse_term_uac3_iterm_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_1, UAC_MIXER_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC_MIXER_UNIT):
+		case PTYPE(UAC_VERSION_3, UAC3_MIXER_UNIT):
+			return parse_term_mixer_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_1, UAC_SELECTOR_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC_SELECTOR_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SELECTOR):
+		case PTYPE(UAC_VERSION_3, UAC3_SELECTOR_UNIT):
+		case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SELECTOR):
+			return parse_term_selector_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_1, UAC1_PROCESSING_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC2_PROCESSING_UNIT_V2):
+		case PTYPE(UAC_VERSION_3, UAC3_PROCESSING_UNIT):
+			return parse_term_proc_unit(state, term, p1, id,
+						    UAC3_PROCESSING_UNIT);
+		case PTYPE(UAC_VERSION_2, UAC2_EFFECT_UNIT):
+		case PTYPE(UAC_VERSION_3, UAC3_EFFECT_UNIT):
+			return parse_term_effect_unit(state, term, p1, id);
+		case PTYPE(UAC_VERSION_1, UAC1_EXTENSION_UNIT):
+		case PTYPE(UAC_VERSION_2, UAC2_EXTENSION_UNIT_V2):
+		case PTYPE(UAC_VERSION_3, UAC3_EXTENSION_UNIT):
+			return parse_term_proc_unit(state, term, p1, id,
+						    UAC3_EXTENSION_UNIT);
+		case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SOURCE):
+			return parse_term_uac2_clock_source(state, term, p1, id);
+		case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SOURCE):
+			return parse_term_uac3_clock_source(state, term, p1, id);
+		default:
+			return -ENODEV;
+		}
+	}
+	return -ENODEV;
+}
+
+
+static int check_input_term(struct mixer_build *state, int id,
+			    struct usb_audio_term *term)
+{
+	memset(term, 0, sizeof(*term));
+	memset(state->termbitmap, 0, sizeof(state->termbitmap));
+	return __check_input_term(state, id, term);
+}
+
+/*
+ * Feature Unit
+ */
+
+/* feature unit control information */
+struct usb_feature_control_info {
+	int control;
+	const char *name;
+	int type;	/* data type for uac1 */
+	int type_uac2;	/* data type for uac2 if different from uac1, else -1 */
+};
+
+static const struct usb_feature_control_info audio_feature_info[] = {
+	{ UAC_FU_MUTE,			"Mute",			USB_MIXER_INV_BOOLEAN, -1 },
+	{ UAC_FU_VOLUME,		"Volume",		USB_MIXER_S16, -1 },
+	{ UAC_FU_BASS,			"Tone Control - Bass",	USB_MIXER_S8, -1 },
+	{ UAC_FU_MID,			"Tone Control - Mid",	USB_MIXER_S8, -1 },
+	{ UAC_FU_TREBLE,		"Tone Control - Treble", USB_MIXER_S8, -1 },
+	{ UAC_FU_GRAPHIC_EQUALIZER,	"Graphic Equalizer",	USB_MIXER_S8, -1 }, /* FIXME: not implemented yet */
+	{ UAC_FU_AUTOMATIC_GAIN,	"Auto Gain Control",	USB_MIXER_BOOLEAN, -1 },
+	{ UAC_FU_DELAY,			"Delay Control",	USB_MIXER_U16, USB_MIXER_U32 },
+	{ UAC_FU_BASS_BOOST,		"Bass Boost",		USB_MIXER_BOOLEAN, -1 },
+	{ UAC_FU_LOUDNESS,		"Loudness",		USB_MIXER_BOOLEAN, -1 },
+	/* UAC2 specific */
+	{ UAC2_FU_INPUT_GAIN,		"Input Gain Control",	USB_MIXER_S16, -1 },
+	{ UAC2_FU_INPUT_GAIN_PAD,	"Input Gain Pad Control", USB_MIXER_S16, -1 },
+	{ UAC2_FU_PHASE_INVERTER,	 "Phase Inverter Control", USB_MIXER_BOOLEAN, -1 },
+};
+
+static void usb_mixer_elem_info_free(struct usb_mixer_elem_info *cval)
+{
+	kfree(cval);
+}
+
+/* private_free callback */
+void snd_usb_mixer_elem_free(struct snd_kcontrol *kctl)
+{
+	usb_mixer_elem_info_free(kctl->private_data);
+	kctl->private_data = NULL;
+}
+
+/*
+ * interface to ALSA control for feature/mixer units
+ */
+
+/* volume control quirks */
+static void volume_control_quirks(struct usb_mixer_elem_info *cval,
+				  struct snd_kcontrol *kctl)
+{
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+
+	if (chip->quirk_flags & QUIRK_FLAG_MIC_RES_384) {
+		if (!strcmp(kctl->id.name, "Mic Capture Volume")) {
+			usb_audio_info(chip,
+				"set resolution quirk: cval->res = 384\n");
+			cval->res = 384;
+		}
+	} else if (chip->quirk_flags & QUIRK_FLAG_MIC_RES_16) {
+		if (!strcmp(kctl->id.name, "Mic Capture Volume")) {
+			usb_audio_info(chip,
+				"set resolution quirk: cval->res = 16\n");
+			cval->res = 16;
+		}
+	}
+
+	switch (chip->usb_id) {
+	case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
+	case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C600 */
+		if (strcmp(kctl->id.name, "Effect Duration") == 0) {
+			cval->min = 0x0000;
+			cval->max = 0xffff;
+			cval->res = 0x00e6;
+			break;
+		}
+		if (strcmp(kctl->id.name, "Effect Volume") == 0 ||
+		    strcmp(kctl->id.name, "Effect Feedback Volume") == 0) {
+			cval->min = 0x00;
+			cval->max = 0xff;
+			break;
+		}
+		if (strstr(kctl->id.name, "Effect Return") != NULL) {
+			cval->min = 0xb706;
+			cval->max = 0xff7b;
+			cval->res = 0x0073;
+			break;
+		}
+		if ((strstr(kctl->id.name, "Playback Volume") != NULL) ||
+			(strstr(kctl->id.name, "Effect Send") != NULL)) {
+			cval->min = 0xb5fb; /* -73 dB = 0xb6ff */
+			cval->max = 0xfcfe;
+			cval->res = 0x0073;
+		}
+		break;
+
+	case USB_ID(0x0763, 0x2081): /* M-Audio Fast Track Ultra 8R */
+	case USB_ID(0x0763, 0x2080): /* M-Audio Fast Track Ultra */
+		if (strcmp(kctl->id.name, "Effect Duration") == 0) {
+			usb_audio_info(chip,
+				       "set quirk for FTU Effect Duration\n");
+			cval->min = 0x0000;
+			cval->max = 0x7f00;
+			cval->res = 0x0100;
+			break;
+		}
+		if (strcmp(kctl->id.name, "Effect Volume") == 0 ||
+		    strcmp(kctl->id.name, "Effect Feedback Volume") == 0) {
+			usb_audio_info(chip,
+				       "set quirks for FTU Effect Feedback/Volume\n");
+			cval->min = 0x00;
+			cval->max = 0x7f;
+			break;
+		}
+		break;
+
+	case USB_ID(0x0d8c, 0x0103):
+		if (!strcmp(kctl->id.name, "PCM Playback Volume")) {
+			usb_audio_info(chip,
+				 "set volume quirk for CM102-A+/102S+\n");
+			cval->min = -256;
+		}
+		break;
+
+	case USB_ID(0x045e, 0x070f): /* MS LifeChat LX-3000 Headset */
+		if (!strcmp(kctl->id.name, "Speaker Playback Volume")) {
+			usb_audio_info(chip,
+				"set volume quirk for MS LifeChat LX-3000\n");
+			cval->res = 192;
+		}
+		break;
+
+	case USB_ID(0x0471, 0x0101):
+	case USB_ID(0x0471, 0x0104):
+	case USB_ID(0x0471, 0x0105):
+	case USB_ID(0x0672, 0x1041):
+	/* quirk for UDA1321/N101.
+	 * note that detection between firmware 2.1.1.7 (N101)
+	 * and later 2.1.1.21 is not very clear from datasheets.
+	 * I hope that the min value is -15360 for newer firmware --jk
+	 */
+		if (!strcmp(kctl->id.name, "PCM Playback Volume") &&
+		    cval->min == -15616) {
+			usb_audio_info(chip,
+				 "set volume quirk for UDA1321/N101 chip\n");
+			cval->max = -256;
+		}
+		break;
+
+	case USB_ID(0x046d, 0x09a4):
+		if (!strcmp(kctl->id.name, "Mic Capture Volume")) {
+			usb_audio_info(chip,
+				"set volume quirk for QuickCam E3500\n");
+			cval->min = 6080;
+			cval->max = 8768;
+			cval->res = 192;
+		}
+		break;
+
+	case USB_ID(0x0495, 0x3042): /* ESS Technology Asus USB DAC */
+		if ((strstr(kctl->id.name, "Playback Volume") != NULL) ||
+			strstr(kctl->id.name, "Capture Volume") != NULL) {
+			cval->min >>= 8;
+			cval->max = 0;
+			cval->res = 1;
+		}
+		break;
+
+	case USB_ID(0x0e6f, 0x024a): /* PDP Riffmaster for PS4 */
+	case USB_ID(0x0e6f, 0x0249): /* PDP Riffmaster for PS5 */
+		if (!strcmp(kctl->id.name, "PCM Playback Volume")) {
+			usb_audio_info(chip,
+				"set volume quirk for PDP Riffmaster for PS4/PS5\n");
+			cval->min = -2560; /* Mute under it */
+		}
+		break;
+
+	case USB_ID(0x3302, 0x12db): /* MOONDROP Quark2 */
+		if (!strcmp(kctl->id.name, "PCM Playback Volume")) {
+			usb_audio_info(chip,
+				"set volume quirk for MOONDROP Quark2\n");
+			cval->min = -14208; /* Mute under it */
+		}
+		break;
+	case USB_ID(0x12d1, 0x3a07): /* Huawei Technologies Co., Ltd. CM-Q3 */
+		if (!strcmp(kctl->id.name, "PCM Playback Volume")) {
+			usb_audio_info(chip,
+				       "set volume quirk for Huawei Technologies Co., Ltd. CM-Q3\n");
+			cval->min = -11264; /* Mute under it */
+		}
+		break;
+	case USB_ID(0x31b2, 0x0111): /* MOONDROP JU Jiu */
+		if (!strcmp(kctl->id.name, "PCM Playback Volume")) {
+			usb_audio_info(chip,
+				       "set volume quirk for MOONDROP JU Jiu\n");
+			cval->min = -10880; /* Mute under it */
+		}
+		break;
+	}
+}
+
+/* forcibly initialize the current mixer value; if GET_CUR fails, set to
+ * the minimum as default
+ */
+static void init_cur_mix_raw(struct usb_mixer_elem_info *cval, int ch, int idx)
+{
+	int val, err;
+
+	err = snd_usb_get_cur_mix_value(cval, ch, idx, &val);
+	if (!err)
+		return;
+	if (!cval->head.mixer->ignore_ctl_error && !cval->get_cur_broken)
+		usb_audio_warn(cval->head.mixer->chip,
+			       "%d:%d: failed to get current value for ch %d (%d)\n",
+			       cval->head.id, mixer_ctrl_intf(cval->head.mixer),
+			       ch, err);
+	snd_usb_set_cur_mix_value(cval, ch, idx, cval->min);
+}
+
+/*
+ * Additional checks for sticky GET_CUR
+ *
+ * Some devices' volume control mixers have sticky GET_CUR, which implies either
+ * stubbed SET_CUR or broken GET_CUR. For the former case, the mixer accepts
+ * SET_CUR but do absolutely nothing, so falling back to soft mixer is the only
+ * way to control the volume. For the latter case, the mixer has effective
+ * SET_CUR despite GET_CUR being constant, and the mixer is usable as long as we
+ * always provide mixer value from the ceche.
+ *
+ * Check the return values of GET_CUR with different SET_CUR values. Consider
+ * GET_CUR as sticky if GET_CUR always returns a constant value.
+ *
+ * Unfortunately, we can't distinguish between stubbed SET_CUR and broken
+ * GET_CUR with simple read-back tests. Disabling the mixer regardless and
+ * forcing userspace to use soft mixer instead can lead to audible distortion at
+ * low volume on some wireless headphones, probably due to their poorly-
+ * performed lossy codec.
+ *
+ * Instead, mark GET_CUR as broken regardless and only provide mixer value from
+ * the cache. Users may opt into soft mixer in userspace audio stack if they
+ * need it.
+ */
+static int check_sticky_volume_control(struct usb_mixer_elem_info *cval,
+				       int channel, int saved)
+{
+	int sticky_test_values[] = { cval->min, cval->max };
+	int test, check, i;
+
+	for (i = 0; i < ARRAY_SIZE(sticky_test_values); i++) {
+		test = sticky_test_values[i];
+		if (test == saved)
+			continue;
+
+		/* Assume non-sticky on failure. */
+		if (snd_usb_set_cur_mix_value(cval, channel, 0, test) ||
+		    get_cur_mix_raw(cval, channel, &check) ||
+		    check != saved) /* SET_CUR effective, non-sticky. */
+			return 0;
+	}
+
+	usb_audio_info(cval->head.mixer->chip,
+		       "%d:%d: broken mixer GET_CUR (%d/%d/%d => %d)\n",
+		       cval->head.id, mixer_ctrl_intf(cval->head.mixer),
+		       cval->min, cval->max, cval->res, saved);
+
+	cval->get_cur_broken = 1;
+	return -ENXIO;
+}
+
+/*
+ * Additional checks for the proper resolution
+ *
+ * Some devices report smaller resolutions than actually reacting.
+ * They don't return errors but simply clip to the lower aligned value.
+ */
+static void check_volume_control_res(struct usb_mixer_elem_info *cval,
+				     int channel, int saved)
+{
+	int last_valid_res = cval->res;
+	int test, check;
+
+	for (;;) {
+		test = saved;
+		if (test < cval->max)
+			test += cval->res;
+		else
+			test -= cval->res;
+
+		if (test < cval->min || test > cval->max ||
+		    snd_usb_set_cur_mix_value(cval, channel, 0, test) ||
+		    get_cur_mix_raw(cval, channel, &check)) {
+			cval->res = last_valid_res;
+			break;
+		}
+		if (test == check)
+			break;
+
+		cval->res *= 2;
+	}
+}
+
+/*
+ * retrieve the minimum and maximum values for the specified control
+ */
+static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
+				   int default_min, struct snd_kcontrol *kctl)
+{
+	int i, idx, ret = 0;
+
+	/* for failsafe */
+	cval->min = default_min;
+	cval->max = cval->min + 1;
+	cval->res = 1;
+	cval->dBmin = cval->dBmax = 0;
+
+	if (cval->val_type == USB_MIXER_BOOLEAN ||
+	    cval->val_type == USB_MIXER_INV_BOOLEAN) {
+		cval->initialized = 1;
+	} else {
+		int minchn = 0;
+		if (cval->cmask) {
+			for (i = 0; i < MAX_CHANNELS; i++)
+				if (cval->cmask & BIT(i)) {
+					minchn = i + 1;
+					break;
+				}
+		}
+		if (get_ctl_value(cval, UAC_GET_MAX, (cval->control << 8) | minchn, &cval->max) < 0 ||
+		    get_ctl_value(cval, UAC_GET_MIN, (cval->control << 8) | minchn, &cval->min) < 0) {
+			usb_audio_err(cval->head.mixer->chip,
+				      "%d:%d: cannot get min/max values for control %d (id %d)\n",
+				   cval->head.id, mixer_ctrl_intf(cval->head.mixer),
+							       cval->control, cval->head.id);
+			return -EAGAIN;
+		}
+		if (get_ctl_value(cval, UAC_GET_RES,
+				  (cval->control << 8) | minchn,
+				  &cval->res) < 0) {
+			cval->res = 1;
+		} else if (cval->head.mixer->protocol == UAC_VERSION_1) {
+			int last_valid_res = cval->res;
+
+			while (cval->res > 1) {
+				if (snd_usb_mixer_set_ctl_value(cval, UAC_SET_RES,
+								(cval->control << 8) | minchn,
+								cval->res / 2) < 0)
+					break;
+				cval->res /= 2;
+			}
+			if (get_ctl_value(cval, UAC_GET_RES,
+					  (cval->control << 8) | minchn, &cval->res) < 0)
+				cval->res = last_valid_res;
+		}
+		if (cval->res == 0)
+			cval->res = 1;
+
+		if (cval->min < cval->max) {
+			int saved;
+
+			if (get_cur_mix_raw(cval, minchn, &saved) < 0)
+				goto no_checks;
+
+			ret = check_sticky_volume_control(cval, minchn, saved);
+			if (ret)
+				goto no_checks;
+
+			if (cval->min + cval->res < cval->max)
+				check_volume_control_res(cval, minchn, saved);
+
+			snd_usb_set_cur_mix_value(cval, minchn, 0, saved);
+		}
+
+no_checks:
+		/*
+		 * Got a non-fatal failure during sanity checks.
+		 *
+		 * Do not propagate mixer values written by sanity checks.
+		 * Instead, rely on init_cur_mix_raw() to initialize the mixer
+		 * properly.
+		 */
+		if (ret)
+			cval->cached = 0;
+
+		cval->initialized = 1;
+	}
+
+	if (kctl)
+		volume_control_quirks(cval, kctl);
+
+	/* USB descriptions contain the dB scale in 1/256 dB unit
+	 * while ALSA TLV contains in 1/100 dB unit
+	 */
+	cval->dBmin = (convert_signed_value(cval, cval->min) * 100) / 256;
+	cval->dBmax = (convert_signed_value(cval, cval->max) * 100) / 256;
+	if (cval->dBmin > cval->dBmax) {
+		/* something is wrong; assume it's either from/to 0dB */
+		if (cval->dBmin < 0)
+			cval->dBmax = 0;
+		else if (cval->dBmin > 0)
+			cval->dBmin = 0;
+		if (cval->dBmin > cval->dBmax) {
+			/* totally crap, return an error */
+			return -EINVAL;
+		}
+	} else {
+		/* if the max volume is too low, it's likely a bogus range;
+		 * here we use -96dB as the threshold
+		 */
+		if (cval->dBmax <= -9600) {
+			usb_audio_info(cval->head.mixer->chip,
+				       "%d:%d: bogus dB values (%d/%d), disabling dB reporting\n",
+				       cval->head.id, mixer_ctrl_intf(cval->head.mixer),
+				       cval->dBmin, cval->dBmax);
+			cval->dBmin = cval->dBmax = 0;
+		}
+	}
+
+	/* initialize all elements */
+	if (!cval->cmask) {
+		init_cur_mix_raw(cval, 0, 0);
+	} else {
+		idx = 0;
+		for (i = 0; i < MAX_CHANNELS; i++) {
+			if (cval->cmask & BIT(i)) {
+				init_cur_mix_raw(cval, i + 1, idx);
+				idx++;
+			}
+		}
+	}
+
+	/*
+	 * When GET_CUR is sticky, the saved value is bogus, so mixer values set
+	 * by the sanity checks must be discarded through init_cur_mix_raw().
+	 * After that, we can clear the flag as per QUIRK_FLAG_MIXER_GET_CUR_OK.
+	 */
+	if (cval->head.mixer->chip->quirk_flags & QUIRK_FLAG_MIXER_GET_CUR_OK)
+		cval->get_cur_broken = 0;
+
+	return 0;
+}
+
+#define get_min_max(cval, def)	get_min_max_with_quirks(cval, def, NULL)
+
+/* get the max value advertised via control API */
+static int get_max_exposed(struct usb_mixer_elem_info *cval)
+{
+	if (!cval->max_exposed) {
+		if (cval->res)
+			cval->max_exposed =
+				DIV_ROUND_UP(cval->max - cval->min, cval->res);
+		else
+			cval->max_exposed = cval->max - cval->min;
+	}
+	return cval->max_exposed;
+}
+
+/* get a feature/mixer unit info */
+static int mixer_ctl_feature_info(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int ret;
+
+	if (cval->val_type == USB_MIXER_BOOLEAN ||
+	    cval->val_type == USB_MIXER_INV_BOOLEAN)
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	else
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = cval->channels;
+	if (cval->val_type != USB_MIXER_BOOLEAN &&
+	    cval->val_type != USB_MIXER_INV_BOOLEAN) {
+		if (!cval->initialized) {
+			ret = get_min_max_with_quirks(cval, 0, kcontrol);
+			if ((ret >= 0 || ret == -EAGAIN) &&
+			    cval->initialized && cval->dBmin >= cval->dBmax) {
+				kcontrol->vd[0].access &= 
+					~(SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+					  SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
+				snd_ctl_notify(cval->head.mixer->chip->card,
+					       SNDRV_CTL_EVENT_MASK_INFO,
+					       &kcontrol->id);
+			}
+		}
+	}
+
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = get_max_exposed(cval);
+	return 0;
+}
+
+/* get the current value from feature/mixer unit */
+static int mixer_ctl_feature_get(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int c, cnt, val, err;
+
+	ucontrol->value.integer.value[0] = cval->min;
+	if (cval->cmask) {
+		cnt = 0;
+		for (c = 0; c < MAX_CHANNELS; c++) {
+			if (!(cval->cmask & BIT(c)))
+				continue;
+			err = snd_usb_get_cur_mix_value(cval, c + 1, cnt, &val);
+			if (err < 0)
+				return filter_error(cval, err);
+			val = get_relative_value(cval, val);
+			ucontrol->value.integer.value[cnt] = val;
+			cnt++;
+		}
+		return 0;
+	} else {
+		/* master channel */
+		err = snd_usb_get_cur_mix_value(cval, 0, 0, &val);
+		if (err < 0)
+			return filter_error(cval, err);
+		val = get_relative_value(cval, val);
+		ucontrol->value.integer.value[0] = val;
+	}
+	return 0;
+}
+
+/* put the current value to feature/mixer unit */
+static int mixer_ctl_feature_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int max_val = get_max_exposed(cval);
+	int c, cnt, val, oval, err;
+	int changed = 0;
+
+	if (cval->cmask) {
+		cnt = 0;
+		for (c = 0; c < MAX_CHANNELS; c++) {
+			if (!(cval->cmask & BIT(c)))
+				continue;
+			err = snd_usb_get_cur_mix_value(cval, c + 1, cnt, &oval);
+			if (err < 0)
+				return filter_error(cval, err);
+			val = ucontrol->value.integer.value[cnt];
+			if (val < 0 || val > max_val)
+				return -EINVAL;
+			val = get_abs_value(cval, val);
+			if (oval != val) {
+				err = snd_usb_set_cur_mix_value(cval, c + 1,
+								cnt, val);
+				if (err < 0)
+					return filter_error(cval, err);
+				changed = 1;
+			}
+			cnt++;
+		}
+	} else {
+		/* master channel */
+		err = snd_usb_get_cur_mix_value(cval, 0, 0, &oval);
+		if (err < 0)
+			return filter_error(cval, err);
+		val = ucontrol->value.integer.value[0];
+		if (val < 0 || val > max_val)
+			return -EINVAL;
+		val = get_abs_value(cval, val);
+		if (val != oval) {
+			err = snd_usb_set_cur_mix_value(cval, 0, 0, val);
+			if (err < 0)
+				return filter_error(cval, err);
+			changed = 1;
+		}
+	}
+	return changed;
+}
+
+/* get the boolean value from the master channel of a UAC control */
+static int mixer_ctl_master_bool_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int val, err;
+
+	err = snd_usb_get_cur_mix_value(cval, 0, 0, &val);
+	if (err < 0)
+		return filter_error(cval, err);
+	val = (val != 0);
+	ucontrol->value.integer.value[0] = val;
+	return 0;
+}
+
+static int get_connector_value(struct usb_mixer_elem_info *cval,
+			       char *name, int *val)
+{
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+	int idx = 0, validx, ret;
+
+	validx = cval->control << 8 | 0;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err) {
+		ret = -EIO;
+		goto error;
+	}
+
+	idx = mixer_ctrl_intf(cval->head.mixer) | (cval->head.id << 8);
+	if (cval->head.mixer->protocol == UAC_VERSION_2) {
+		struct uac2_connectors_ctl_blk uac2_conn;
+
+		ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), UAC2_CS_CUR,
+				      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+				      validx, idx, &uac2_conn, sizeof(uac2_conn));
+		if (val)
+			*val = !!uac2_conn.bNrChannels;
+	} else { /* UAC_VERSION_3 */
+		struct uac3_insertion_ctl_blk uac3_conn;
+
+		ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), UAC2_CS_CUR,
+				      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+				      validx, idx, &uac3_conn, sizeof(uac3_conn));
+		if (val)
+			*val = !!uac3_conn.bmConInserted;
+	}
+
+	if (ret < 0) {
+		if (name && strstr(name, "Speaker")) {
+			if (val)
+				*val = 1;
+			return 0;
+		}
+error:
+		usb_audio_err(chip,
+			"cannot get connectors status: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
+			UAC_GET_CUR, validx, idx, cval->val_type);
+
+		if (val)
+			*val = 0;
+
+		return filter_error(cval, ret);
+	}
+
+	return ret;
+}
+
+/* get the connectors status and report it as boolean type */
+static int mixer_ctl_connector_get(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int ret, val;
+
+	ret = get_connector_value(cval, kcontrol->id.name, &val);
+
+	if (ret < 0)
+		return ret;
+
+	ucontrol->value.integer.value[0] = val;
+	return 0;
+}
+
+static const struct snd_kcontrol_new usb_feature_unit_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "", /* will be filled later manually */
+	.info = mixer_ctl_feature_info,
+	.get = mixer_ctl_feature_get,
+	.put = mixer_ctl_feature_put,
+};
+
+/* the read-only variant */
+static const struct snd_kcontrol_new usb_feature_unit_ctl_ro = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "", /* will be filled later manually */
+	.info = mixer_ctl_feature_info,
+	.get = mixer_ctl_feature_get,
+	.put = NULL,
+};
+
+/*
+ * A control which shows the boolean value from reading a UAC control on
+ * the master channel.
+ */
+static const struct snd_kcontrol_new usb_bool_master_control_ctl_ro = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "", /* will be filled later manually */
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.info = snd_ctl_boolean_mono_info,
+	.get = mixer_ctl_master_bool_get,
+	.put = NULL,
+};
+
+static const struct snd_kcontrol_new usb_connector_ctl_ro = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "", /* will be filled later manually */
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.info = snd_ctl_boolean_mono_info,
+	.get = mixer_ctl_connector_get,
+	.put = NULL,
+};
+
+/*
+ * This symbol is exported in order to allow the mixer quirks to
+ * hook up to the standard feature unit control mechanism
+ */
+const struct snd_kcontrol_new *snd_usb_feature_unit_ctl = &usb_feature_unit_ctl;
+
+/*
+ * build a feature control
+ */
+static size_t append_ctl_name(struct snd_kcontrol *kctl, const char *str)
+{
+	return strlcat(kctl->id.name, str, sizeof(kctl->id.name));
+}
+
+/*
+ * A lot of headsets/headphones have a "Speaker" mixer. Make sure we
+ * rename it to "Headphone". We determine if something is a headphone
+ * similar to how udev determines form factor.
+ */
+static void check_no_speaker_on_headset(struct snd_kcontrol *kctl,
+					struct snd_card *card)
+{
+	static const char * const names_to_check[] = {
+		"Headset", "headset", "Headphone", "headphone", NULL};
+	const char * const *s;
+	bool found = false;
+
+	if (strcmp("Speaker", kctl->id.name))
+		return;
+
+	for (s = names_to_check; *s; s++)
+		if (strstr(card->shortname, *s)) {
+			found = true;
+			break;
+		}
+
+	if (!found)
+		return;
+
+	snd_ctl_rename(card, kctl, "Headphone");
+}
+
+static const struct usb_feature_control_info *get_feature_control_info(int control)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(audio_feature_info); ++i) {
+		if (audio_feature_info[i].control == control)
+			return &audio_feature_info[i];
+	}
+	return NULL;
+}
+
+static bool check_insane_volume_range(struct usb_mixer_interface *mixer,
+				      struct snd_kcontrol *kctl,
+				      struct usb_mixer_elem_info *cval)
+{
+	int range, steps, threshold;
+
+	/*
+	 * If a device quirk has overrode our TLV callback, no warning should
+	 * be generated since our checks are only meaningful for dB volume.
+	 */
+	if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) ||
+	    kctl->tlv.c != snd_usb_mixer_vol_tlv)
+		return false;
+
+	/*
+	 * Meaningless volume control capability (<1dB). This should cover
+	 * devices mapping their volume to val = 0/100/1, which are very likely
+	 * to be quirky.
+	 */
+	range = cval->max - cval->min;
+	if (range < 256) {
+		usb_audio_warn(mixer->chip,
+			       "Warning! Unlikely small volume range (=%u), linear volume or custom curve?",
+			       range);
+		return true;
+	}
+
+	steps = range / cval->res;
+
+	/*
+	 * There are definitely devices with ~20,000 ranges (e.g., HyperX Cloud
+	 * III with val = -18944/0/1), so we use some heuristics here:
+	 *
+	 * min < 0 < max: Attenuator + amplifier? Likely to be sane
+	 *
+	 * min < 0 = max: DSP? Voltage attenuator with FW conversion to dB?
+	 * Likely to be sane
+	 *
+	 * min < max < 0: Measured values? Neutral
+	 *
+	 * min = 0 < max: Oversimplified FW conversion? Linear volume? Likely to
+	 * be quirky (e.g., MV-SILICON)
+	 *
+	 * 0 < min < max: Amplifier with fixed gains? Likely to be quirky
+	 * (e.g., Logitech webcam)
+	 */
+	if (cval->min < 0 && 0 <= cval->max)
+		threshold = 24576; /* 65535 * (3 / 8) */
+	else if (cval->min < cval->max && cval->max < 0)
+		threshold = 1024;
+	else
+		threshold = 384;
+
+	if (steps > threshold) {
+		usb_audio_warn(mixer->chip,
+			       "Warning! Unlikely big volume step count (=%u), linear volume or wrong cval->res?",
+			       steps);
+		return true;
+	}
+
+	return false;
+}
+
+static void __build_feature_ctl(struct usb_mixer_interface *mixer,
+				const struct usbmix_name_map *imap,
+				u64 ctl_mask, int control,
+				struct usb_audio_term *iterm,
+				struct usb_audio_term *oterm,
+				int unitid, int nameid, int readonly_mask)
+{
+	const struct usb_feature_control_info *ctl_info;
+	unsigned int len = 0;
+	int mapped_name = 0;
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *cval;
+	const struct usbmix_name_map *map;
+	int ret;
+
+	if (control == UAC_FU_GRAPHIC_EQUALIZER) {
+		/* FIXME: not supported yet */
+		return;
+	}
+
+	map = find_map(imap, unitid, control);
+	if (check_ignored_ctl(map))
+		return;
+
+	cval = kzalloc_obj(*cval);
+	if (!cval)
+		return;
+	snd_usb_mixer_elem_init_std(&cval->head, mixer, unitid);
+	cval->control = control;
+	cval->cmask = ctl_mask;
+
+	ctl_info = get_feature_control_info(control);
+	if (!ctl_info) {
+		usb_mixer_elem_info_free(cval);
+		return;
+	}
+	if (mixer->protocol == UAC_VERSION_1)
+		cval->val_type = ctl_info->type;
+	else /* UAC_VERSION_2 */
+		cval->val_type = ctl_info->type_uac2 >= 0 ?
+			ctl_info->type_uac2 : ctl_info->type;
+
+	if (ctl_mask == 0) {
+		cval->channels = 1;	/* master channel */
+		cval->master_readonly = readonly_mask;
+	} else {
+		int i, c = 0;
+		for (i = 0; i < MAX_CHANNELS; i++)
+			if (ctl_mask & BIT(i))
+				c++;
+		cval->channels = c;
+		cval->ch_readonly = readonly_mask;
+	}
+
+	/*
+	 * If all channels in the mask are marked read-only, make the control
+	 * read-only. snd_usb_set_cur_mix_value() will check the mask again and won't
+	 * issue write commands to read-only channels.
+	 */
+	if (cval->channels == readonly_mask)
+		kctl = snd_ctl_new1(&usb_feature_unit_ctl_ro, cval);
+	else
+		kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
+
+	if (!kctl) {
+		usb_audio_err(mixer->chip, "cannot malloc kcontrol\n");
+		usb_mixer_elem_info_free(cval);
+		return;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
+	mapped_name = len != 0;
+	if (!len && nameid)
+		len = snd_usb_copy_string_desc(mixer->chip, nameid,
+				kctl->id.name, sizeof(kctl->id.name));
+
+	switch (control) {
+	case UAC_FU_MUTE:
+	case UAC_FU_VOLUME:
+		/*
+		 * determine the control name.  the rule is:
+		 * - if a name id is given in descriptor, use it.
+		 * - if the connected input can be determined, then use the name
+		 *   of terminal type.
+		 * - if the connected output can be determined, use it.
+		 * - otherwise, anonymous name.
+		 */
+		if (!len) {
+			if (iterm)
+				len = get_term_name(mixer->chip, iterm,
+						    kctl->id.name,
+						    sizeof(kctl->id.name), 1);
+			if (!len && oterm)
+				len = get_term_name(mixer->chip, oterm,
+						    kctl->id.name,
+						    sizeof(kctl->id.name), 1);
+			if (!len)
+				snprintf(kctl->id.name, sizeof(kctl->id.name),
+					 "Feature %d", unitid);
+		}
+
+		if (!mapped_name)
+			check_no_speaker_on_headset(kctl, mixer->chip->card);
+
+		/*
+		 * determine the stream direction:
+		 * if the connected output is USB stream, then it's likely a
+		 * capture stream.  otherwise it should be playback (hopefully :)
+		 */
+		if (!mapped_name && oterm && !(oterm->type >> 16)) {
+			if ((oterm->type & 0xff00) == 0x0100)
+				append_ctl_name(kctl, " Capture");
+			else
+				append_ctl_name(kctl, " Playback");
+		}
+		append_ctl_name(kctl, control == UAC_FU_MUTE ?
+				" Switch" : " Volume");
+		break;
+	default:
+		if (!len)
+			strscpy(kctl->id.name, audio_feature_info[control-1].name,
+				sizeof(kctl->id.name));
+		break;
+	}
+
+	/* get min/max values */
+	ret = get_min_max_with_quirks(cval, 0, kctl);
+
+	/* skip a bogus volume range */
+	if ((ret < 0 && ret != -EAGAIN) || cval->max <= cval->min) {
+		usb_audio_dbg(mixer->chip,
+			      "[%d] FU [%s] skipped due to invalid volume\n",
+			      cval->head.id, kctl->id.name);
+		snd_ctl_free_one(kctl);
+		return;
+	}
+
+
+	if (control == UAC_FU_VOLUME) {
+		check_mapped_dB(map, cval);
+		if (cval->dBmin < cval->dBmax || !cval->initialized) {
+			kctl->tlv.c = snd_usb_mixer_vol_tlv;
+			kctl->vd[0].access |=
+				SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+				SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+		}
+	}
+
+	snd_usb_mixer_fu_apply_quirk(mixer, cval, unitid, kctl);
+
+	if (check_insane_volume_range(mixer, kctl, cval)) {
+		usb_audio_warn(mixer->chip, "[%d] FU [%s] ch = %d, val = %d/%d/%d\n",
+			       cval->head.id, kctl->id.name, cval->channels,
+			       cval->min, cval->max, cval->res);
+	} else {
+		usb_audio_dbg(mixer->chip, "[%d] FU [%s] ch = %d, val = %d/%d/%d\n",
+			      cval->head.id, kctl->id.name, cval->channels,
+			      cval->min, cval->max, cval->res);
+	}
+
+	snd_usb_mixer_add_control(&cval->head, kctl);
+}
+
+static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
+			      u64 ctl_mask, int control,
+			      struct usb_audio_term *iterm, int unitid,
+			      int readonly_mask)
+{
+	struct uac_feature_unit_descriptor *desc = raw_desc;
+	int nameid = uac_feature_unit_iFeature(desc);
+
+	__build_feature_ctl(state->mixer, state->map, ctl_mask, control,
+			iterm, &state->oterm, unitid, nameid, readonly_mask);
+}
+
+static void build_feature_ctl_badd(struct usb_mixer_interface *mixer,
+			      u64 ctl_mask, int control, int unitid,
+			      const struct usbmix_name_map *badd_map)
+{
+	__build_feature_ctl(mixer, badd_map, ctl_mask, control,
+			NULL, NULL, unitid, 0, 0);
+}
+
+static void get_connector_control_name(struct usb_mixer_interface *mixer,
+				       struct usb_audio_term *term,
+				       bool is_input, char *name, int name_size)
+{
+	int name_len = get_term_name(mixer->chip, term, name, name_size, 0);
+
+	if (name_len == 0)
+		name_len = strscpy(name, "Unknown", name_size);
+	if (name_len < 0)
+		return;
+
+	/*
+	 *  sound/core/ctljack.c has a convention of naming jack controls
+	 * by ending in " Jack".  Make it slightly more useful by
+	 * indicating Input or Output after the terminal name.
+	 */
+	if (is_input)
+		strscpy(name + name_len, " - Input Jack", name_size - name_len);
+	else
+		strscpy(name + name_len, " - Output Jack", name_size - name_len);
+}
+
+/* get connector value to "wake up" the USB audio */
+static int connector_mixer_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
+
+	get_connector_value(cval, NULL, NULL);
+	return 0;
+}
+
+/* Build a mixer control for a UAC connector control (jack-detect) */
+static void build_connector_control(struct usb_mixer_interface *mixer,
+				    const struct usbmix_name_map *imap,
+				    struct usb_audio_term *term, bool is_input)
+{
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *cval;
+	const struct usbmix_name_map *map;
+
+	map = find_map(imap, term->id, 0);
+	if (check_ignored_ctl(map))
+		return;
+
+	cval = kzalloc_obj(*cval);
+	if (!cval)
+		return;
+	snd_usb_mixer_elem_init_std(&cval->head, mixer, term->id);
+
+	/* set up a specific resume callback */
+	cval->head.resume = connector_mixer_resume;
+
+	/*
+	 * UAC2: The first byte from reading the UAC2_TE_CONNECTOR control returns the
+	 * number of channels connected.
+	 *
+	 * UAC3: The first byte specifies size of bitmap for the inserted controls. The
+	 * following byte(s) specifies which connectors are inserted.
+	 *
+	 * This boolean ctl will simply report if any channels are connected
+	 * or not.
+	 */
+	if (mixer->protocol == UAC_VERSION_2)
+		cval->control = UAC2_TE_CONNECTOR;
+	else /* UAC_VERSION_3 */
+		cval->control = UAC3_TE_INSERTION;
+
+	cval->val_type = USB_MIXER_BOOLEAN;
+	cval->channels = 1; /* report true if any channel is connected */
+	cval->min = 0;
+	cval->max = 1;
+	kctl = snd_ctl_new1(&usb_connector_ctl_ro, cval);
+	if (!kctl) {
+		usb_audio_err(mixer->chip, "cannot malloc kcontrol\n");
+		usb_mixer_elem_info_free(cval);
+		return;
+	}
+
+	if (check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name)))
+		strlcat(kctl->id.name, " Jack", sizeof(kctl->id.name));
+	else
+		get_connector_control_name(mixer, term, is_input, kctl->id.name,
+					   sizeof(kctl->id.name));
+	kctl->private_free = snd_usb_mixer_elem_free;
+	snd_usb_mixer_add_control(&cval->head, kctl);
+}
+
+static int parse_clock_source_unit(struct mixer_build *state, int unitid,
+				   void *_ftr)
+{
+	struct uac_clock_source_descriptor *hdr = _ftr;
+	struct usb_mixer_elem_info *cval;
+	struct snd_kcontrol *kctl;
+	int ret;
+
+	if (state->mixer->protocol != UAC_VERSION_2)
+		return -EINVAL;
+
+	/*
+	 * The only property of this unit we are interested in is the
+	 * clock source validity. If that isn't readable, just bail out.
+	 */
+	if (!uac_v2v3_control_is_readable(hdr->bmControls,
+				      UAC2_CS_CONTROL_CLOCK_VALID))
+		return 0;
+
+	cval = kzalloc_obj(*cval);
+	if (!cval)
+		return -ENOMEM;
+
+	snd_usb_mixer_elem_init_std(&cval->head, state->mixer, hdr->bClockID);
+
+	cval->min = 0;
+	cval->max = 1;
+	cval->channels = 1;
+	cval->val_type = USB_MIXER_BOOLEAN;
+	cval->control = UAC2_CS_CONTROL_CLOCK_VALID;
+
+	cval->master_readonly = 1;
+	/* From UAC2 5.2.5.1.2 "Only the get request is supported." */
+	kctl = snd_ctl_new1(&usb_bool_master_control_ctl_ro, cval);
+
+	if (!kctl) {
+		usb_mixer_elem_info_free(cval);
+		return -ENOMEM;
+	}
+
+	kctl->private_free = snd_usb_mixer_elem_free;
+	ret = snd_usb_copy_string_desc(state->chip, hdr->iClockSource,
+				       kctl->id.name, sizeof(kctl->id.name));
+	if (ret > 0)
+		append_ctl_name(kctl, " Validity");
+	else
+		snprintf(kctl->id.name, sizeof(kctl->id.name),
+			 "Clock Source %d Validity", hdr->bClockID);
+
+	return snd_usb_mixer_add_control(&cval->head, kctl);
+}
+
+/*
+ * parse a feature unit
+ *
+ * most of controls are defined here.
+ */
+static int parse_audio_feature_unit(struct mixer_build *state, int unitid,
+				    void *_ftr)
+{
+	int channels, i, j;
+	struct usb_audio_term iterm;
+	unsigned int master_bits;
+	int err, csize;
+	struct uac_feature_unit_descriptor *hdr = _ftr;
+	__u8 *bmaControls;
+
+	if (state->mixer->protocol == UAC_VERSION_1) {
+		csize = hdr->bControlSize;
+		channels = (hdr->bLength - 7) / csize - 1;
+		bmaControls = hdr->bmaControls;
+	} else if (state->mixer->protocol == UAC_VERSION_2) {
+		struct uac2_feature_unit_descriptor *ftr = _ftr;
+		csize = 4;
+		channels = (hdr->bLength - 6) / 4 - 1;
+		bmaControls = ftr->bmaControls;
+	} else { /* UAC_VERSION_3 */
+		struct uac3_feature_unit_descriptor *ftr = _ftr;
+
+		csize = 4;
+		channels = (ftr->bLength - 7) / 4 - 1;
+		bmaControls = ftr->bmaControls;
+	}
+
+	if (channels > MAX_CHANNELS) {
+		usb_audio_info(state->chip,
+			       "usbmixer: too many channels (%d) in unit %d\n",
+			       channels, unitid);
+		return -EINVAL;
+	}
+
+	/* parse the source unit */
+	err = parse_audio_unit(state, hdr->bSourceID);
+	if (err < 0)
+		return err;
+
+	/* determine the input source type and name */
+	err = check_input_term(state, hdr->bSourceID, &iterm);
+	if (err < 0)
+		return err;
+
+	master_bits = snd_usb_combine_bytes(bmaControls, csize);
+	/* master configuration quirks */
+	switch (state->chip->usb_id) {
+	case USB_ID(0x08bb, 0x2702):
+		usb_audio_info(state->chip,
+			       "usbmixer: master volume quirk for PCM2702 chip\n");
+		/* disable non-functional volume control */
+		master_bits &= ~UAC_CONTROL_BIT(UAC_FU_VOLUME);
+		break;
+	case USB_ID(0x1130, 0xf211):
+		usb_audio_info(state->chip,
+			       "usbmixer: volume control quirk for Tenx TP6911 Audio Headset\n");
+		/* disable non-functional volume control */
+		channels = 0;
+		break;
+
+	}
+
+	if (state->mixer->protocol == UAC_VERSION_1) {
+		/* check all control types */
+		for (i = 0; i < 10; i++) {
+			u64 ch_bits = 0;
+			int control = audio_feature_info[i].control;
+
+			for (j = 0; j < channels; j++) {
+				unsigned int mask;
+
+				mask = snd_usb_combine_bytes(bmaControls +
+							     csize * (j+1), csize);
+				if (mask & BIT(i))
+					ch_bits |= BIT(j);
+			}
+			/* audio class v1 controls are never read-only */
+
+			/*
+			 * The first channel must be set
+			 * (for ease of programming).
+			 */
+			if (ch_bits & 1)
+				build_feature_ctl(state, _ftr, ch_bits, control,
+						  &iterm, unitid, 0);
+			if (master_bits & BIT(i))
+				build_feature_ctl(state, _ftr, 0, control,
+						  &iterm, unitid, 0);
+		}
+	} else { /* UAC_VERSION_2/3 */
+		for (i = 0; i < ARRAY_SIZE(audio_feature_info); i++) {
+			u64 ch_bits = 0;
+			unsigned int ch_read_only = 0;
+			int control = audio_feature_info[i].control;
+
+			for (j = 0; j < channels; j++) {
+				unsigned int mask;
+
+				mask = snd_usb_combine_bytes(bmaControls +
+							     csize * (j+1), csize);
+				if (uac_v2v3_control_is_readable(mask, control)) {
+					ch_bits |= BIT(j);
+					if (!uac_v2v3_control_is_writeable(mask, control))
+						ch_read_only |= BIT(j);
+				}
+			}
+
+			/*
+			 * NOTE: build_feature_ctl() will mark the control
+			 * read-only if all channels are marked read-only in
+			 * the descriptors. Otherwise, the control will be
+			 * reported as writeable, but the driver will not
+			 * actually issue a write command for read-only
+			 * channels.
+			 */
+
+			/*
+			 * The first channel must be set
+			 * (for ease of programming).
+			 */
+			if (ch_bits & 1)
+				build_feature_ctl(state, _ftr, ch_bits, control,
+						  &iterm, unitid, ch_read_only);
+			if (uac_v2v3_control_is_readable(master_bits, control))
+				build_feature_ctl(state, _ftr, 0, control,
+						  &iterm, unitid,
+						  !uac_v2v3_control_is_writeable(master_bits,
+										 control));
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Mixer Unit
+ */
+
+/* check whether the given in/out overflows bmMixerControls matrix */
+static bool mixer_bitmap_overflow(struct uac_mixer_unit_descriptor *desc,
+				  int protocol, int num_ins, int num_outs)
+{
+	u8 *hdr = (u8 *)desc;
+	u8 *c = uac_mixer_unit_bmControls(desc, protocol);
+	size_t rest; /* remaining bytes after bmMixerControls */
+
+	switch (protocol) {
+	case UAC_VERSION_1:
+	default:
+		rest = 1; /* iMixer */
+		break;
+	case UAC_VERSION_2:
+		rest = 2; /* bmControls + iMixer */
+		break;
+	case UAC_VERSION_3:
+		rest = 6; /* bmControls + wMixerDescrStr */
+		break;
+	}
+
+	/* overflow? */
+	return c + (num_ins * num_outs + 7) / 8 + rest > hdr + hdr[0];
+}
+
+/*
+ * build a mixer unit control
+ *
+ * the callbacks are identical with feature unit.
+ * input channel number (zero based) is given in control field instead.
+ */
+static void build_mixer_unit_ctl(struct mixer_build *state,
+				 struct uac_mixer_unit_descriptor *desc,
+				 int in_pin, int in_ch, int num_outs,
+				 int unitid, struct usb_audio_term *iterm)
+{
+	struct usb_mixer_elem_info *cval;
+	unsigned int i, len;
+	struct snd_kcontrol *kctl;
+	const struct usbmix_name_map *map;
+	int ret;
+
+	map = find_map(state->map, unitid, 0);
+	if (check_ignored_ctl(map))
+		return;
+
+	cval = kzalloc_obj(*cval);
+	if (!cval)
+		return;
+
+	snd_usb_mixer_elem_init_std(&cval->head, state->mixer, unitid);
+	cval->control = in_ch + 1; /* based on 1 */
+	cval->val_type = USB_MIXER_S16;
+	for (i = 0; i < num_outs; i++) {
+		__u8 *c = uac_mixer_unit_bmControls(desc, state->mixer->protocol);
+
+		if (check_matrix_bitmap(c, in_ch, i, num_outs)) {
+			cval->cmask |= BIT(i);
+			cval->channels++;
+		}
+	}
+
+	/* get min/max values */
+	ret = get_min_max(cval, 0);
+	if (ret < 0 && ret != -EAGAIN) {
+		usb_mixer_elem_info_free(cval);
+		return;
+	}
+
+	kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
+	if (!kctl) {
+		usb_audio_err(state->chip, "cannot malloc kcontrol\n");
+		usb_mixer_elem_info_free(cval);
+		return;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
+	if (!len)
+		len = get_term_name(state->chip, iterm, kctl->id.name,
+				    sizeof(kctl->id.name), 0);
+	if (!len)
+		snprintf(kctl->id.name, sizeof(kctl->id.name), "Mixer Source %d", in_ch + 1);
+
+	append_ctl_name(kctl, " Volume");
+
+	usb_audio_dbg(state->chip, "[%d] MU [%s] ch = %d, val = %d/%d\n",
+		    cval->head.id, kctl->id.name, cval->channels, cval->min, cval->max);
+	snd_usb_mixer_add_control(&cval->head, kctl);
+}
+
+static int parse_audio_input_terminal(struct mixer_build *state, int unitid,
+				      void *raw_desc)
+{
+	struct usb_audio_term iterm;
+	unsigned int control, bmctls, term_id;
+
+	if (state->mixer->protocol == UAC_VERSION_2) {
+		struct uac2_input_terminal_descriptor *d_v2 = raw_desc;
+		control = UAC2_TE_CONNECTOR;
+		term_id = d_v2->bTerminalID;
+		bmctls = le16_to_cpu(d_v2->bmControls);
+	} else if (state->mixer->protocol == UAC_VERSION_3) {
+		struct uac3_input_terminal_descriptor *d_v3 = raw_desc;
+		control = UAC3_TE_INSERTION;
+		term_id = d_v3->bTerminalID;
+		bmctls = le32_to_cpu(d_v3->bmControls);
+	} else {
+		return 0; /* UAC1. No Insertion control */
+	}
+
+	check_input_term(state, term_id, &iterm);
+
+	/* Check for jack detection. */
+	if ((iterm.type & 0xff00) != 0x0100 &&
+	    uac_v2v3_control_is_readable(bmctls, control))
+		build_connector_control(state->mixer, state->map, &iterm, true);
+
+	return 0;
+}
+
+/*
+ * parse a mixer unit
+ */
+static int parse_audio_mixer_unit(struct mixer_build *state, int unitid,
+				  void *raw_desc)
+{
+	struct uac_mixer_unit_descriptor *desc = raw_desc;
+	struct usb_audio_term iterm;
+	int input_pins, num_ins, num_outs;
+	int pin, ich, err;
+
+	err = uac_mixer_unit_get_channels(state, desc);
+	if (err < 0) {
+		usb_audio_err(state->chip,
+			      "invalid MIXER UNIT descriptor %d\n",
+			      unitid);
+		return err;
+	}
+
+	num_outs = err;
+	input_pins = desc->bNrInPins;
+
+	num_ins = 0;
+	ich = 0;
+	for (pin = 0; pin < input_pins; pin++) {
+		err = parse_audio_unit(state, desc->baSourceID[pin]);
+		if (err < 0)
+			continue;
+		/* no bmControls field (e.g. Maya44) -> ignore */
+		if (!num_outs)
+			continue;
+		err = check_input_term(state, desc->baSourceID[pin], &iterm);
+		if (err < 0)
+			return err;
+		num_ins += iterm.channels;
+		if (mixer_bitmap_overflow(desc, state->mixer->protocol,
+					  num_ins, num_outs))
+			break;
+		for (; ich < num_ins; ich++) {
+			int och, ich_has_controls = 0;
+
+			for (och = 0; och < num_outs; och++) {
+				__u8 *c = uac_mixer_unit_bmControls(desc,
+						state->mixer->protocol);
+
+				if (check_matrix_bitmap(c, ich, och, num_outs)) {
+					ich_has_controls = 1;
+					break;
+				}
+			}
+			if (ich_has_controls)
+				build_mixer_unit_ctl(state, desc, pin, ich, num_outs,
+						     unitid, &iterm);
+		}
+	}
+	return 0;
+}
+
+/*
+ * Processing Unit / Extension Unit
+ */
+
+/* get callback for processing/extension unit */
+static int mixer_ctl_procunit_get(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int err, val;
+
+	err = get_cur_ctl_value(cval, cval->control << 8, &val);
+	if (err < 0) {
+		ucontrol->value.integer.value[0] = cval->min;
+		return filter_error(cval, err);
+	}
+	val = get_relative_value(cval, val);
+	ucontrol->value.integer.value[0] = val;
+	return 0;
+}
+
+/* put callback for processing/extension unit */
+static int mixer_ctl_procunit_put(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int val, oval, err;
+
+	err = get_cur_ctl_value(cval, cval->control << 8, &oval);
+	if (err < 0)
+		return filter_error(cval, err);
+	val = ucontrol->value.integer.value[0];
+	if (val < 0 || val > get_max_exposed(cval))
+		return -EINVAL;
+	val = get_abs_value(cval, val);
+	if (val != oval) {
+		err = set_cur_ctl_value(cval, cval->control << 8, val);
+		if (err < 0)
+			return filter_error(cval, err);
+		return 1;
+	}
+	return 0;
+}
+
+/* alsa control interface for processing/extension unit */
+static const struct snd_kcontrol_new mixer_procunit_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "", /* will be filled later */
+	.info = mixer_ctl_feature_info,
+	.get = mixer_ctl_procunit_get,
+	.put = mixer_ctl_procunit_put,
+};
+
+/*
+ * predefined data for processing units
+ */
+struct procunit_value_info {
+	int control;
+	const char *suffix;
+	int val_type;
+	int min_value;
+};
+
+struct procunit_info {
+	int type;
+	char *name;
+	const struct procunit_value_info *values;
+};
+
+static const struct procunit_value_info undefined_proc_info[] = {
+	{ 0x00, "Control Undefined", 0 },
+	{ 0 }
+};
+
+static const struct procunit_value_info updown_proc_info[] = {
+	{ UAC_UD_ENABLE, "Switch", USB_MIXER_BOOLEAN },
+	{ UAC_UD_MODE_SELECT, "Mode Select", USB_MIXER_U8, 1 },
+	{ 0 }
+};
+static const struct procunit_value_info prologic_proc_info[] = {
+	{ UAC_DP_ENABLE, "Switch", USB_MIXER_BOOLEAN },
+	{ UAC_DP_MODE_SELECT, "Mode Select", USB_MIXER_U8, 1 },
+	{ 0 }
+};
+static const struct procunit_value_info threed_enh_proc_info[] = {
+	{ UAC_3D_ENABLE, "Switch", USB_MIXER_BOOLEAN },
+	{ UAC_3D_SPACE, "Spaciousness", USB_MIXER_U8 },
+	{ 0 }
+};
+static const struct procunit_value_info reverb_proc_info[] = {
+	{ UAC_REVERB_ENABLE, "Switch", USB_MIXER_BOOLEAN },
+	{ UAC_REVERB_LEVEL, "Level", USB_MIXER_U8 },
+	{ UAC_REVERB_TIME, "Time", USB_MIXER_U16 },
+	{ UAC_REVERB_FEEDBACK, "Feedback", USB_MIXER_U8 },
+	{ 0 }
+};
+static const struct procunit_value_info chorus_proc_info[] = {
+	{ UAC_CHORUS_ENABLE, "Switch", USB_MIXER_BOOLEAN },
+	{ UAC_CHORUS_LEVEL, "Level", USB_MIXER_U8 },
+	{ UAC_CHORUS_RATE, "Rate", USB_MIXER_U16 },
+	{ UAC_CHORUS_DEPTH, "Depth", USB_MIXER_U16 },
+	{ 0 }
+};
+static const struct procunit_value_info dcr_proc_info[] = {
+	{ UAC_DCR_ENABLE, "Switch", USB_MIXER_BOOLEAN },
+	{ UAC_DCR_RATE, "Ratio", USB_MIXER_U16 },
+	{ UAC_DCR_MAXAMPL, "Max Amp", USB_MIXER_S16 },
+	{ UAC_DCR_THRESHOLD, "Threshold", USB_MIXER_S16 },
+	{ UAC_DCR_ATTACK_TIME, "Attack Time", USB_MIXER_U16 },
+	{ UAC_DCR_RELEASE_TIME, "Release Time", USB_MIXER_U16 },
+	{ 0 }
+};
+
+static const struct procunit_info procunits[] = {
+	{ UAC_PROCESS_UP_DOWNMIX, "Up Down", updown_proc_info },
+	{ UAC_PROCESS_DOLBY_PROLOGIC, "Dolby Prologic", prologic_proc_info },
+	{ UAC_PROCESS_STEREO_EXTENDER, "3D Stereo Extender", threed_enh_proc_info },
+	{ UAC_PROCESS_REVERB, "Reverb", reverb_proc_info },
+	{ UAC_PROCESS_CHORUS, "Chorus", chorus_proc_info },
+	{ UAC_PROCESS_DYN_RANGE_COMP, "DCR", dcr_proc_info },
+	{ 0 },
+};
+
+static const struct procunit_value_info uac3_updown_proc_info[] = {
+	{ UAC3_UD_MODE_SELECT, "Mode Select", USB_MIXER_U8, 1 },
+	{ 0 }
+};
+static const struct procunit_value_info uac3_stereo_ext_proc_info[] = {
+	{ UAC3_EXT_WIDTH_CONTROL, "Width Control", USB_MIXER_U8 },
+	{ 0 }
+};
+
+static const struct procunit_info uac3_procunits[] = {
+	{ UAC3_PROCESS_UP_DOWNMIX, "Up Down", uac3_updown_proc_info },
+	{ UAC3_PROCESS_STEREO_EXTENDER, "3D Stereo Extender", uac3_stereo_ext_proc_info },
+	{ UAC3_PROCESS_MULTI_FUNCTION, "Multi-Function", undefined_proc_info },
+	{ 0 },
+};
+
+/*
+ * predefined data for extension units
+ */
+static const struct procunit_value_info clock_rate_xu_info[] = {
+	{ USB_XU_CLOCK_RATE_SELECTOR, "Selector", USB_MIXER_U8, 0 },
+	{ 0 }
+};
+static const struct procunit_value_info clock_source_xu_info[] = {
+	{ USB_XU_CLOCK_SOURCE_SELECTOR, "External", USB_MIXER_BOOLEAN },
+	{ 0 }
+};
+static const struct procunit_value_info spdif_format_xu_info[] = {
+	{ USB_XU_DIGITAL_FORMAT_SELECTOR, "SPDIF/AC3", USB_MIXER_BOOLEAN },
+	{ 0 }
+};
+static const struct procunit_value_info soft_limit_xu_info[] = {
+	{ USB_XU_SOFT_LIMIT_SELECTOR, " ", USB_MIXER_BOOLEAN },
+	{ 0 }
+};
+static const struct procunit_info extunits[] = {
+	{ USB_XU_CLOCK_RATE, "Clock rate", clock_rate_xu_info },
+	{ USB_XU_CLOCK_SOURCE, "DigitalIn CLK source", clock_source_xu_info },
+	{ USB_XU_DIGITAL_IO_STATUS, "DigitalOut format:", spdif_format_xu_info },
+	{ USB_XU_DEVICE_OPTIONS, "AnalogueIn Soft Limit", soft_limit_xu_info },
+	{ 0 }
+};
+
+/*
+ * build a processing/extension unit
+ */
+static int build_audio_procunit(struct mixer_build *state, int unitid,
+				void *raw_desc, const struct procunit_info *list,
+				bool extension_unit)
+{
+	struct uac_processing_unit_descriptor *desc = raw_desc;
+	int num_ins;
+	struct usb_mixer_elem_info *cval;
+	struct snd_kcontrol *kctl;
+	int i, err, nameid, type, len, val;
+	const struct procunit_info *info;
+	const struct procunit_value_info *valinfo;
+	const struct usbmix_name_map *map;
+	static const struct procunit_value_info default_value_info[] = {
+		{ 0x01, "Switch", USB_MIXER_BOOLEAN },
+		{ 0 }
+	};
+	static const struct procunit_info default_info = {
+		0, NULL, default_value_info
+	};
+	const char *name = extension_unit ?
+		"Extension Unit" : "Processing Unit";
+
+	num_ins = desc->bNrInPins;
+	for (i = 0; i < num_ins; i++) {
+		err = parse_audio_unit(state, desc->baSourceID[i]);
+		if (err < 0)
+			return err;
+	}
+
+	type = le16_to_cpu(desc->wProcessType);
+	for (info = list; info && info->type; info++)
+		if (info->type == type)
+			break;
+	if (!info || !info->type)
+		info = &default_info;
+
+	for (valinfo = info->values; valinfo->control; valinfo++) {
+		__u8 *controls = uac_processing_unit_bmControls(desc, state->mixer->protocol);
+
+		if (state->mixer->protocol == UAC_VERSION_1) {
+			if (!(controls[valinfo->control / 8] &
+			      BIT((valinfo->control % 8) - 1)))
+				continue;
+		} else { /* UAC_VERSION_2/3 */
+			if (!uac_v2v3_control_is_readable(controls[valinfo->control / 8],
+							  valinfo->control))
+				continue;
+		}
+
+		map = find_map(state->map, unitid, valinfo->control);
+		if (check_ignored_ctl(map))
+			continue;
+		cval = kzalloc_obj(*cval);
+		if (!cval)
+			return -ENOMEM;
+		snd_usb_mixer_elem_init_std(&cval->head, state->mixer, unitid);
+		cval->control = valinfo->control;
+		cval->val_type = valinfo->val_type;
+		cval->channels = 1;
+
+		if (state->mixer->protocol > UAC_VERSION_1 &&
+		    !uac_v2v3_control_is_writeable(controls[valinfo->control / 8],
+						   valinfo->control))
+			cval->master_readonly = 1;
+
+		/* get min/max values */
+		switch (type) {
+		case USB_XU_CLOCK_RATE:
+			/*
+			 * E-Mu USB 0404/0202/TrackerPre/0204
+			 * samplerate control quirk
+			 */
+			cval->min = 0;
+			cval->max = 5;
+			cval->res = 1;
+			cval->initialized = 1;
+			break;
+		case UAC_PROCESS_UP_DOWNMIX: {
+			bool mode_sel = false;
+
+			switch (state->mixer->protocol) {
+			case UAC_VERSION_1:
+			case UAC_VERSION_2:
+			default:
+				if (cval->control == UAC_UD_MODE_SELECT)
+					mode_sel = true;
+				break;
+			case UAC_VERSION_3:
+				if (cval->control == UAC3_UD_MODE_SELECT)
+					mode_sel = true;
+				break;
+			}
+
+			if (mode_sel) {
+				__u8 *control_spec = uac_processing_unit_specific(desc,
+								state->mixer->protocol);
+				cval->min = 1;
+				cval->max = control_spec[0];
+				cval->res = 1;
+				cval->initialized = 1;
+				break;
+			}
+
+			fallthrough;
+		}
+		default:
+			err = get_min_max(cval, valinfo->min_value);
+			if (err < 0 && err != -EAGAIN) {
+				usb_mixer_elem_info_free(cval);
+				return err;
+			}
+		}
+
+		err = get_cur_ctl_value(cval, cval->control << 8, &val);
+		if (err < 0) {
+			usb_mixer_elem_info_free(cval);
+			return -EINVAL;
+		}
+
+		kctl = snd_ctl_new1(&mixer_procunit_ctl, cval);
+		if (!kctl) {
+			usb_mixer_elem_info_free(cval);
+			return -ENOMEM;
+		}
+		kctl->private_free = snd_usb_mixer_elem_free;
+
+		if (check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name))) {
+			/* nothing */ ;
+		} else if (info->name) {
+			strscpy(kctl->id.name, info->name, sizeof(kctl->id.name));
+		} else {
+			if (extension_unit)
+				nameid = uac_extension_unit_iExtension(desc, state->mixer->protocol);
+			else
+				nameid = uac_processing_unit_iProcessing(desc, state->mixer->protocol);
+			len = 0;
+			if (nameid)
+				len = snd_usb_copy_string_desc(state->chip,
+							       nameid,
+							       kctl->id.name,
+							       sizeof(kctl->id.name));
+			if (!len)
+				strscpy(kctl->id.name, name, sizeof(kctl->id.name));
+		}
+		append_ctl_name(kctl, " ");
+		append_ctl_name(kctl, valinfo->suffix);
+
+		usb_audio_dbg(state->chip,
+			      "[%d] PU [%s] ch = %d, val = %d/%d\n",
+			      cval->head.id, kctl->id.name, cval->channels,
+			      cval->min, cval->max);
+
+		err = snd_usb_mixer_add_control(&cval->head, kctl);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static int parse_audio_processing_unit(struct mixer_build *state, int unitid,
+				       void *raw_desc)
+{
+	switch (state->mixer->protocol) {
+	case UAC_VERSION_1:
+	case UAC_VERSION_2:
+	default:
+		return build_audio_procunit(state, unitid, raw_desc,
+					    procunits, false);
+	case UAC_VERSION_3:
+		return build_audio_procunit(state, unitid, raw_desc,
+					    uac3_procunits, false);
+	}
+}
+
+static int parse_audio_extension_unit(struct mixer_build *state, int unitid,
+				      void *raw_desc)
+{
+	/*
+	 * Note that we parse extension units with processing unit descriptors.
+	 * That's ok as the layout is the same.
+	 */
+	return build_audio_procunit(state, unitid, raw_desc, extunits, true);
+}
+
+/*
+ * Selector Unit
+ */
+
+/*
+ * info callback for selector unit
+ * use an enumerator type for routing
+ */
+static int mixer_ctl_selector_info(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	const char **itemlist = (const char **)kcontrol->private_value;
+
+	if (snd_BUG_ON(!itemlist))
+		return -EINVAL;
+	return snd_ctl_enum_info(uinfo, 1, cval->max, itemlist);
+}
+
+/* get callback for selector unit */
+static int mixer_ctl_selector_get(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int val, err;
+
+	err = get_cur_ctl_value(cval, cval->control << 8, &val);
+	if (err < 0) {
+		ucontrol->value.enumerated.item[0] = 0;
+		return filter_error(cval, err);
+	}
+	val = get_relative_value(cval, val);
+	ucontrol->value.enumerated.item[0] = val;
+	return 0;
+}
+
+/* put callback for selector unit */
+static int mixer_ctl_selector_put(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	int val, oval, err;
+
+	err = get_cur_ctl_value(cval, cval->control << 8, &oval);
+	if (err < 0)
+		return filter_error(cval, err);
+	val = ucontrol->value.enumerated.item[0];
+	if (val < 0 || val >= cval->max) /* here cval->max = # elements */
+		return -EINVAL;
+	val = get_abs_value(cval, val);
+	if (val != oval) {
+		err = set_cur_ctl_value(cval, cval->control << 8, val);
+		if (err < 0)
+			return filter_error(cval, err);
+		return 1;
+	}
+	return 0;
+}
+
+/* alsa control interface for selector unit */
+static const struct snd_kcontrol_new mixer_selectunit_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "", /* will be filled later */
+	.info = mixer_ctl_selector_info,
+	.get = mixer_ctl_selector_get,
+	.put = mixer_ctl_selector_put,
+};
+
+/*
+ * private free callback.
+ * free both private_data and private_value
+ */
+static void usb_mixer_selector_elem_free(struct snd_kcontrol *kctl)
+{
+	int i, num_ins = 0;
+
+	if (kctl->private_data) {
+		struct usb_mixer_elem_info *cval = kctl->private_data;
+		num_ins = cval->max;
+		usb_mixer_elem_info_free(cval);
+		kctl->private_data = NULL;
+	}
+	if (kctl->private_value) {
+		char **itemlist = (char **)kctl->private_value;
+		for (i = 0; i < num_ins; i++)
+			kfree(itemlist[i]);
+		kfree(itemlist);
+		kctl->private_value = 0;
+	}
+}
+
+/*
+ * parse a selector unit
+ */
+static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
+				     void *raw_desc)
+{
+	struct uac_selector_unit_descriptor *desc = raw_desc;
+	unsigned int i, nameid, len;
+	int err;
+	struct usb_mixer_elem_info *cval;
+	struct snd_kcontrol *kctl;
+	const struct usbmix_name_map *map;
+	char **namelist;
+
+	for (i = 0; i < desc->bNrInPins; i++) {
+		err = parse_audio_unit(state, desc->baSourceID[i]);
+		if (err < 0)
+			return err;
+	}
+
+	if (desc->bNrInPins == 1) /* only one ? nonsense! */
+		return 0;
+
+	map = find_map(state->map, unitid, 0);
+	if (check_ignored_ctl(map))
+		return 0;
+
+	cval = kzalloc_obj(*cval);
+	if (!cval)
+		return -ENOMEM;
+	snd_usb_mixer_elem_init_std(&cval->head, state->mixer, unitid);
+	cval->val_type = USB_MIXER_U8;
+	cval->channels = 1;
+	cval->min = 1;
+	cval->max = desc->bNrInPins;
+	cval->res = 1;
+	cval->initialized = 1;
+
+	switch (state->mixer->protocol) {
+	case UAC_VERSION_1:
+	default:
+		cval->control = 0;
+		break;
+	case UAC_VERSION_2:
+	case UAC_VERSION_3:
+		if (desc->bDescriptorSubtype == UAC2_CLOCK_SELECTOR ||
+		    desc->bDescriptorSubtype == UAC3_CLOCK_SELECTOR)
+			cval->control = UAC2_CX_CLOCK_SELECTOR;
+		else /* UAC2/3_SELECTOR_UNIT */
+			cval->control = UAC2_SU_SELECTOR;
+		break;
+	}
+
+	namelist = kcalloc(desc->bNrInPins, sizeof(char *), GFP_KERNEL);
+	if (!namelist) {
+		err = -ENOMEM;
+		goto error_cval;
+	}
+#define MAX_ITEM_NAME_LEN	64
+	for (i = 0; i < desc->bNrInPins; i++) {
+		struct usb_audio_term iterm;
+		namelist[i] = kmalloc(MAX_ITEM_NAME_LEN, GFP_KERNEL);
+		if (!namelist[i]) {
+			err = -ENOMEM;
+			goto error_name;
+		}
+		len = check_mapped_selector_name(state, unitid, i, namelist[i],
+						 MAX_ITEM_NAME_LEN);
+		if (! len && check_input_term(state, desc->baSourceID[i], &iterm) >= 0)
+			len = get_term_name(state->chip, &iterm, namelist[i],
+					    MAX_ITEM_NAME_LEN, 0);
+		if (! len)
+			scnprintf(namelist[i], MAX_ITEM_NAME_LEN, "Input %u", i);
+	}
+
+	kctl = snd_ctl_new1(&mixer_selectunit_ctl, cval);
+	if (! kctl) {
+		usb_audio_err(state->chip, "cannot malloc kcontrol\n");
+		err = -ENOMEM;
+		goto error_name;
+	}
+	kctl->private_value = (unsigned long)namelist;
+	kctl->private_free = usb_mixer_selector_elem_free;
+
+	/* check the static mapping table at first */
+	len = check_mapped_name(map, kctl->id.name, sizeof(kctl->id.name));
+	if (!len) {
+		/* no mapping ? */
+		switch (state->mixer->protocol) {
+		case UAC_VERSION_1:
+		case UAC_VERSION_2:
+		default:
+		/* if iSelector is given, use it */
+			nameid = uac_selector_unit_iSelector(desc);
+			if (nameid)
+				len = snd_usb_copy_string_desc(state->chip,
+							nameid, kctl->id.name,
+							sizeof(kctl->id.name));
+			break;
+		case UAC_VERSION_3:
+			/* TODO: Class-Specific strings not yet supported */
+			break;
+		}
+
+		/* ... or pick up the terminal name at next */
+		if (!len)
+			len = get_term_name(state->chip, &state->oterm,
+				    kctl->id.name, sizeof(kctl->id.name), 0);
+		/* ... or use the fixed string "USB" as the last resort */
+		if (!len)
+			strscpy(kctl->id.name, "USB", sizeof(kctl->id.name));
+
+		/* and add the proper suffix */
+		if (desc->bDescriptorSubtype == UAC2_CLOCK_SELECTOR ||
+		    desc->bDescriptorSubtype == UAC3_CLOCK_SELECTOR)
+			append_ctl_name(kctl, " Clock Source");
+		else if ((state->oterm.type & 0xff00) == 0x0100)
+			append_ctl_name(kctl, " Capture Source");
+		else
+			append_ctl_name(kctl, " Playback Source");
+	}
+
+	usb_audio_dbg(state->chip, "[%d] SU [%s] items = %d\n",
+		    cval->head.id, kctl->id.name, desc->bNrInPins);
+	return snd_usb_mixer_add_control(&cval->head, kctl);
+
+ error_name:
+	for (i = 0; i < desc->bNrInPins; i++)
+		kfree(namelist[i]);
+	kfree(namelist);
+ error_cval:
+	usb_mixer_elem_info_free(cval);
+	return err;
+}
+
+/*
+ * parse an audio unit recursively
+ */
+
+static int parse_audio_unit(struct mixer_build *state, int unitid)
+{
+	unsigned char *p1;
+	int protocol = state->mixer->protocol;
+
+	if (test_and_set_bit(unitid, state->unitbitmap))
+		return 0; /* the unit already visited */
+
+	p1 = find_audio_control_unit(state, unitid);
+	if (!p1) {
+		usb_audio_err(state->chip, "unit %d not found!\n", unitid);
+		return -EINVAL;
+	}
+
+	if (!snd_usb_validate_audio_desc(p1, protocol)) {
+		usb_audio_dbg(state->chip, "invalid unit %d\n", unitid);
+		return 0; /* skip invalid unit */
+	}
+
+	switch (PTYPE(protocol, p1[2])) {
+	case PTYPE(UAC_VERSION_1, UAC_INPUT_TERMINAL):
+	case PTYPE(UAC_VERSION_2, UAC_INPUT_TERMINAL):
+	case PTYPE(UAC_VERSION_3, UAC_INPUT_TERMINAL):
+		return parse_audio_input_terminal(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC_MIXER_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC_MIXER_UNIT):
+	case PTYPE(UAC_VERSION_3, UAC3_MIXER_UNIT):
+		return parse_audio_mixer_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SOURCE):
+	case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SOURCE):
+		return parse_clock_source_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC_SELECTOR_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC_SELECTOR_UNIT):
+	case PTYPE(UAC_VERSION_3, UAC3_SELECTOR_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SELECTOR):
+	case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SELECTOR):
+		return parse_audio_selector_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC_FEATURE_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC_FEATURE_UNIT):
+	case PTYPE(UAC_VERSION_3, UAC3_FEATURE_UNIT):
+		return parse_audio_feature_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC1_PROCESSING_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC2_PROCESSING_UNIT_V2):
+	case PTYPE(UAC_VERSION_3, UAC3_PROCESSING_UNIT):
+		return parse_audio_processing_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_1, UAC1_EXTENSION_UNIT):
+	case PTYPE(UAC_VERSION_2, UAC2_EXTENSION_UNIT_V2):
+	case PTYPE(UAC_VERSION_3, UAC3_EXTENSION_UNIT):
+		return parse_audio_extension_unit(state, unitid, p1);
+	case PTYPE(UAC_VERSION_2, UAC2_EFFECT_UNIT):
+	case PTYPE(UAC_VERSION_3, UAC3_EFFECT_UNIT):
+		return 0; /* FIXME - effect units not implemented yet */
+	default:
+		usb_audio_err(state->chip,
+			      "unit %u: unexpected type 0x%02x\n",
+			      unitid, p1[2]);
+		return -EINVAL;
+	}
+}
+
+static void snd_usb_mixer_free(struct usb_mixer_interface *mixer)
+{
+	struct usb_mixer_elem_list *list, *next;
+	int id;
+
+	/* kill pending URBs */
+	snd_usb_mixer_disconnect(mixer);
+
+	/* Unregister controls first, snd_ctl_remove() frees the element */
+	if (mixer->id_elems) {
+		for (id = 0; id < MAX_ID_ELEMS; id++) {
+			for (list = mixer->id_elems[id]; list; list = next) {
+				next = list->next_id_elem;
+				if (list->kctl)
+					snd_ctl_remove(mixer->chip->card, list->kctl);
+			}
+		}
+		kfree(mixer->id_elems);
+	}
+	if (mixer->urb) {
+		kfree(mixer->urb->transfer_buffer);
+		usb_free_urb(mixer->urb);
+	}
+	usb_free_urb(mixer->rc_urb);
+	kfree(mixer->rc_setup_packet);
+	kfree(mixer);
+}
+
+static int snd_usb_mixer_dev_free(struct snd_device *device)
+{
+	struct usb_mixer_interface *mixer = device->device_data;
+	snd_usb_mixer_free(mixer);
+	return 0;
+}
+
+/* UAC3 predefined channels configuration */
+struct uac3_badd_profile {
+	int subclass;
+	const char *name;
+	int c_chmask;	/* capture channels mask */
+	int p_chmask;	/* playback channels mask */
+	int st_chmask;	/* side tone mixing channel mask */
+};
+
+static const struct uac3_badd_profile uac3_badd_profiles[] = {
+	{
+		/*
+		 * BAIF, BAOF or combination of both
+		 * IN: Mono or Stereo cfg, Mono alt possible
+		 * OUT: Mono or Stereo cfg, Mono alt possible
+		 */
+		.subclass = UAC3_FUNCTION_SUBCLASS_GENERIC_IO,
+		.name = "GENERIC IO",
+		.c_chmask = -1,		/* dynamic channels */
+		.p_chmask = -1,		/* dynamic channels */
+	},
+	{
+		/* BAOF; Stereo only cfg, Mono alt possible */
+		.subclass = UAC3_FUNCTION_SUBCLASS_HEADPHONE,
+		.name = "HEADPHONE",
+		.p_chmask = 3,
+	},
+	{
+		/* BAOF; Mono or Stereo cfg, Mono alt possible */
+		.subclass = UAC3_FUNCTION_SUBCLASS_SPEAKER,
+		.name = "SPEAKER",
+		.p_chmask = -1,		/* dynamic channels */
+	},
+	{
+		/* BAIF; Mono or Stereo cfg, Mono alt possible */
+		.subclass = UAC3_FUNCTION_SUBCLASS_MICROPHONE,
+		.name = "MICROPHONE",
+		.c_chmask = -1,		/* dynamic channels */
+	},
+	{
+		/*
+		 * BAIOF topology
+		 * IN: Mono only
+		 * OUT: Mono or Stereo cfg, Mono alt possible
+		 */
+		.subclass = UAC3_FUNCTION_SUBCLASS_HEADSET,
+		.name = "HEADSET",
+		.c_chmask = 1,
+		.p_chmask = -1,		/* dynamic channels */
+		.st_chmask = 1,
+	},
+	{
+		/* BAIOF; IN: Mono only; OUT: Stereo only, Mono alt possible */
+		.subclass = UAC3_FUNCTION_SUBCLASS_HEADSET_ADAPTER,
+		.name = "HEADSET ADAPTER",
+		.c_chmask = 1,
+		.p_chmask = 3,
+		.st_chmask = 1,
+	},
+	{
+		/* BAIF + BAOF; IN: Mono only; OUT: Mono only */
+		.subclass = UAC3_FUNCTION_SUBCLASS_SPEAKERPHONE,
+		.name = "SPEAKERPHONE",
+		.c_chmask = 1,
+		.p_chmask = 1,
+	},
+	{ 0 } /* terminator */
+};
+
+static bool uac3_badd_func_has_valid_channels(struct usb_mixer_interface *mixer,
+					      const struct uac3_badd_profile *f,
+					      int c_chmask, int p_chmask)
+{
+	/*
+	 * If both playback/capture channels are dynamic, make sure
+	 * at least one channel is present
+	 */
+	if (f->c_chmask < 0 && f->p_chmask < 0) {
+		if (!c_chmask && !p_chmask) {
+			usb_audio_warn(mixer->chip, "BAAD %s: no channels?",
+				       f->name);
+			return false;
+		}
+		return true;
+	}
+
+	if ((f->c_chmask < 0 && !c_chmask) ||
+	    (f->c_chmask >= 0 && f->c_chmask != c_chmask)) {
+		usb_audio_warn(mixer->chip, "BAAD %s c_chmask mismatch",
+			       f->name);
+		return false;
+	}
+	if ((f->p_chmask < 0 && !p_chmask) ||
+	    (f->p_chmask >= 0 && f->p_chmask != p_chmask)) {
+		usb_audio_warn(mixer->chip, "BAAD %s p_chmask mismatch",
+			       f->name);
+		return false;
+	}
+	return true;
+}
+
+/*
+ * create mixer controls for UAC3 BADD profiles
+ *
+ * UAC3 BADD device doesn't contain CS descriptors thus we will guess everything
+ *
+ * BADD device may contain Mixer Unit, which doesn't have any controls, skip it
+ */
+static int snd_usb_mixer_controls_badd(struct usb_mixer_interface *mixer,
+				       int ctrlif)
+{
+	struct usb_device *dev = mixer->chip->dev;
+	struct usb_interface_assoc_descriptor *assoc;
+	int badd_profile = mixer->chip->badd_profile;
+	const struct uac3_badd_profile *f;
+	const struct usbmix_ctl_map *map;
+	int p_chmask = 0, c_chmask = 0, st_chmask = 0;
+	int i;
+
+	assoc = usb_ifnum_to_if(dev, ctrlif)->intf_assoc;
+	if (!assoc)
+		return -EINVAL;
+
+	/* Detect BADD capture/playback channels from AS EP descriptors */
+	for (i = 0; i < assoc->bInterfaceCount; i++) {
+		int intf = assoc->bFirstInterface + i;
+
+		struct usb_interface *iface;
+		struct usb_host_interface *alts;
+		struct usb_interface_descriptor *altsd;
+		unsigned int maxpacksize;
+		char dir_in;
+		int chmask, num;
+
+		if (intf == ctrlif)
+			continue;
+
+		iface = usb_ifnum_to_if(dev, intf);
+		if (!iface)
+			continue;
+
+		num = iface->num_altsetting;
+
+		if (num < 2)
+			return -EINVAL;
+
+		/*
+		 * The number of Channels in an AudioStreaming interface
+		 * and the audio sample bit resolution (16 bits or 24
+		 * bits) can be derived from the wMaxPacketSize field in
+		 * the Standard AS Audio Data Endpoint descriptor in
+		 * Alternate Setting 1
+		 */
+		alts = &iface->altsetting[1];
+		altsd = get_iface_desc(alts);
+
+		if (altsd->bNumEndpoints < 1)
+			return -EINVAL;
+
+		/* check direction */
+		dir_in = (get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN);
+		maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+
+		switch (maxpacksize) {
+		default:
+			usb_audio_err(mixer->chip,
+				"incorrect wMaxPacketSize 0x%x for BADD profile\n",
+				maxpacksize);
+			return -EINVAL;
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_MONO_16:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_MONO_16:
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_MONO_24:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_MONO_24:
+			chmask = 1;
+			break;
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_STEREO_16:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_STEREO_16:
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_STEREO_24:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_STEREO_24:
+			chmask = 3;
+			break;
+		}
+
+		if (dir_in)
+			c_chmask = chmask;
+		else
+			p_chmask = chmask;
+	}
+
+	usb_audio_dbg(mixer->chip,
+		"UAC3 BADD profile 0x%x: detected c_chmask=%d p_chmask=%d\n",
+		badd_profile, c_chmask, p_chmask);
+
+	/* check the mapping table */
+	for (map = uac3_badd_usbmix_ctl_maps; map->id; map++) {
+		if (map->id == badd_profile)
+			break;
+	}
+
+	if (!map->id)
+		return -EINVAL;
+
+	for (f = uac3_badd_profiles; f->name; f++) {
+		if (badd_profile == f->subclass)
+			break;
+	}
+	if (!f->name)
+		return -EINVAL;
+	if (!uac3_badd_func_has_valid_channels(mixer, f, c_chmask, p_chmask))
+		return -EINVAL;
+	st_chmask = f->st_chmask;
+
+	/* Playback */
+	if (p_chmask) {
+		/* Master channel, always writable */
+		build_feature_ctl_badd(mixer, 0, UAC_FU_MUTE,
+				       UAC3_BADD_FU_ID2, map->map);
+		/* Mono/Stereo volume channels, always writable */
+		build_feature_ctl_badd(mixer, p_chmask, UAC_FU_VOLUME,
+				       UAC3_BADD_FU_ID2, map->map);
+	}
+
+	/* Capture */
+	if (c_chmask) {
+		/* Master channel, always writable */
+		build_feature_ctl_badd(mixer, 0, UAC_FU_MUTE,
+				       UAC3_BADD_FU_ID5, map->map);
+		/* Mono/Stereo volume channels, always writable */
+		build_feature_ctl_badd(mixer, c_chmask, UAC_FU_VOLUME,
+				       UAC3_BADD_FU_ID5, map->map);
+	}
+
+	/* Side tone-mixing */
+	if (st_chmask) {
+		/* Master channel, always writable */
+		build_feature_ctl_badd(mixer, 0, UAC_FU_MUTE,
+				       UAC3_BADD_FU_ID7, map->map);
+		/* Mono volume channel, always writable */
+		build_feature_ctl_badd(mixer, 1, UAC_FU_VOLUME,
+				       UAC3_BADD_FU_ID7, map->map);
+	}
+
+	/* Insertion Control */
+	if (f->subclass == UAC3_FUNCTION_SUBCLASS_HEADSET_ADAPTER) {
+		struct usb_audio_term iterm, oterm;
+
+		/* Input Term - Insertion control */
+		memset(&iterm, 0, sizeof(iterm));
+		iterm.id = UAC3_BADD_IT_ID4;
+		iterm.type = UAC_BIDIR_TERMINAL_HEADSET;
+		build_connector_control(mixer, map->map, &iterm, true);
+
+		/* Output Term - Insertion control */
+		memset(&oterm, 0, sizeof(oterm));
+		oterm.id = UAC3_BADD_OT_ID3;
+		oterm.type = UAC_BIDIR_TERMINAL_HEADSET;
+		build_connector_control(mixer, map->map, &oterm, false);
+	}
+
+	return 0;
+}
+
+/*
+ * create mixer controls
+ *
+ * walk through all UAC_OUTPUT_TERMINAL descriptors to search for mixers
+ */
+static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer)
+{
+	struct mixer_build state;
+	int err;
+	const struct usbmix_ctl_map *map;
+	void *p;
+
+	memset(&state, 0, sizeof(state));
+	state.chip = mixer->chip;
+	state.mixer = mixer;
+	state.buffer = mixer->hostif->extra;
+	state.buflen = mixer->hostif->extralen;
+
+	/* check the mapping table */
+	for (map = usbmix_ctl_maps; map->id; map++) {
+		if (map->id == state.chip->usb_id) {
+			state.map = map->map;
+			state.selector_map = map->selector_map;
+			mixer->connector_map = map->connector_map;
+			break;
+		}
+	}
+
+	p = NULL;
+	while ((p = snd_usb_find_csint_desc(mixer->hostif->extra,
+					    mixer->hostif->extralen,
+					    p, UAC_OUTPUT_TERMINAL)) != NULL) {
+		if (!snd_usb_validate_audio_desc(p, mixer->protocol))
+			continue; /* skip invalid descriptor */
+
+		if (mixer->protocol == UAC_VERSION_1) {
+			struct uac1_output_terminal_descriptor *desc = p;
+
+			/* mark terminal ID as visited */
+			set_bit(desc->bTerminalID, state.unitbitmap);
+			state.oterm.id = desc->bTerminalID;
+			state.oterm.type = le16_to_cpu(desc->wTerminalType);
+			state.oterm.name = desc->iTerminal;
+			err = parse_audio_unit(&state, desc->bSourceID);
+			if (err < 0 && err != -EINVAL)
+				return err;
+		} else if (mixer->protocol == UAC_VERSION_2) {
+			struct uac2_output_terminal_descriptor *desc = p;
+
+			/* mark terminal ID as visited */
+			set_bit(desc->bTerminalID, state.unitbitmap);
+			state.oterm.id = desc->bTerminalID;
+			state.oterm.type = le16_to_cpu(desc->wTerminalType);
+			state.oterm.name = desc->iTerminal;
+			err = parse_audio_unit(&state, desc->bSourceID);
+			if (err < 0 && err != -EINVAL)
+				return err;
+
+			/*
+			 * For UAC2, use the same approach to also add the
+			 * clock selectors
+			 */
+			err = parse_audio_unit(&state, desc->bCSourceID);
+			if (err < 0 && err != -EINVAL)
+				return err;
+
+			if ((state.oterm.type & 0xff00) != 0x0100 &&
+			    uac_v2v3_control_is_readable(le16_to_cpu(desc->bmControls),
+							 UAC2_TE_CONNECTOR)) {
+				build_connector_control(state.mixer, state.map,
+							&state.oterm, false);
+			}
+		} else {  /* UAC_VERSION_3 */
+			struct uac3_output_terminal_descriptor *desc = p;
+
+			/* mark terminal ID as visited */
+			set_bit(desc->bTerminalID, state.unitbitmap);
+			state.oterm.id = desc->bTerminalID;
+			state.oterm.type = le16_to_cpu(desc->wTerminalType);
+			state.oterm.name = le16_to_cpu(desc->wTerminalDescrStr);
+			err = parse_audio_unit(&state, desc->bSourceID);
+			if (err < 0 && err != -EINVAL)
+				return err;
+
+			/*
+			 * For UAC3, use the same approach to also add the
+			 * clock selectors
+			 */
+			err = parse_audio_unit(&state, desc->bCSourceID);
+			if (err < 0 && err != -EINVAL)
+				return err;
+
+			if ((state.oterm.type & 0xff00) != 0x0100 &&
+			    uac_v2v3_control_is_readable(le32_to_cpu(desc->bmControls),
+							 UAC3_TE_INSERTION)) {
+				build_connector_control(state.mixer, state.map,
+							&state.oterm, false);
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int delegate_notify(struct usb_mixer_interface *mixer, int unitid,
+			   u8 *control, u8 *channel)
+{
+	const struct usbmix_connector_map *map = mixer->connector_map;
+
+	if (!map)
+		return unitid;
+
+	for (; map->id; map++) {
+		if (map->id == unitid) {
+			if (control && map->control)
+				*control = map->control;
+			if (channel && map->channel)
+				*channel = map->channel;
+			return map->delegated_id;
+		}
+	}
+	return unitid;
+}
+
+void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid)
+{
+	struct usb_mixer_elem_list *list;
+
+	unitid = delegate_notify(mixer, unitid, NULL, NULL);
+
+	for_each_mixer_elem(list, mixer, unitid) {
+		struct usb_mixer_elem_info *info;
+
+		if (!list->is_std_info)
+			continue;
+		info = mixer_elem_list_to_info(list);
+		/* invalidate cache, so the value is read from the device */
+		if (!info->get_cur_broken)
+			info->cached = 0;
+		snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &list->kctl->id);
+	}
+}
+
+static void snd_usb_mixer_dump_cval(struct snd_info_buffer *buffer,
+				    struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
+	static const char * const val_types[] = {
+		[USB_MIXER_BOOLEAN] = "BOOLEAN",
+		[USB_MIXER_INV_BOOLEAN] = "INV_BOOLEAN",
+		[USB_MIXER_S8] = "S8",
+		[USB_MIXER_U8] = "U8",
+		[USB_MIXER_S16] = "S16",
+		[USB_MIXER_U16] = "U16",
+		[USB_MIXER_S32] = "S32",
+		[USB_MIXER_U32] = "U32",
+		[USB_MIXER_BESPOKEN] = "BESPOKEN",
+	};
+	snd_iprintf(buffer, "    Info: id=%i, control=%i, cmask=0x%llx, "
+			    "channels=%i, type=\"%s\"\n", cval->head.id,
+			    cval->control, cval->cmask, cval->channels,
+			    val_types[cval->val_type]);
+	snd_iprintf(buffer, "    Volume: min=%i, max=%i, dBmin=%i, dBmax=%i\n",
+			    cval->min, cval->max, cval->dBmin, cval->dBmax);
+}
+
+static void snd_usb_mixer_proc_read(struct snd_info_entry *entry,
+				    struct snd_info_buffer *buffer)
+{
+	struct snd_usb_audio *chip = entry->private_data;
+	struct usb_mixer_interface *mixer;
+	struct usb_mixer_elem_list *list;
+	int unitid;
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		snd_iprintf(buffer,
+			"USB Mixer: usb_id=0x%08x, ctrlif=%i, ctlerr=%i\n",
+				chip->usb_id, mixer_ctrl_intf(mixer),
+				mixer->ignore_ctl_error);
+		snd_iprintf(buffer, "Card: %s\n", chip->card->longname);
+		for (unitid = 0; unitid < MAX_ID_ELEMS; unitid++) {
+			for_each_mixer_elem(list, mixer, unitid) {
+				snd_iprintf(buffer, "  Unit: %i\n", list->id);
+				if (list->kctl)
+					snd_iprintf(buffer,
+						    "    Control: name=\"%s\", index=%i\n",
+						    list->kctl->id.name,
+						    list->kctl->id.index);
+				if (list->dump)
+					list->dump(buffer, list);
+			}
+		}
+	}
+}
+
+static void snd_usb_mixer_interrupt_v2(struct usb_mixer_interface *mixer,
+				       int attribute, int value, int index)
+{
+	struct usb_mixer_elem_list *list;
+	__u8 unitid = (index >> 8) & 0xff;
+	__u8 control = (value >> 8) & 0xff;
+	__u8 channel = value & 0xff;
+	unsigned int count = 0;
+
+	if (channel >= MAX_CHANNELS) {
+		usb_audio_dbg(mixer->chip,
+			"%s(): bogus channel number %d\n",
+			__func__, channel);
+		return;
+	}
+
+	unitid = delegate_notify(mixer, unitid, &control, &channel);
+
+	for_each_mixer_elem(list, mixer, unitid)
+		count++;
+
+	if (count == 0)
+		return;
+
+	for_each_mixer_elem(list, mixer, unitid) {
+		struct usb_mixer_elem_info *info;
+
+		if (!list->kctl)
+			continue;
+		if (!list->is_std_info)
+			continue;
+
+		info = mixer_elem_list_to_info(list);
+		if (count > 1 && info->control != control)
+			continue;
+
+		switch (attribute) {
+		case UAC2_CS_CUR:
+			/* invalidate cache, so the value is read from the device */
+			if (!info->get_cur_broken) {
+				if (channel)
+					info->cached &= ~BIT(channel);
+				else /* master channel */
+					info->cached = 0;
+			}
+
+			snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+				       &info->head.kctl->id);
+			break;
+
+		case UAC2_CS_RANGE:
+			/* TODO */
+			break;
+
+		case UAC2_CS_MEM:
+			/* TODO */
+			break;
+
+		default:
+			usb_audio_dbg(mixer->chip,
+				"unknown attribute %d in interrupt\n",
+				attribute);
+			break;
+		} /* switch */
+	}
+}
+
+static void snd_usb_mixer_interrupt(struct urb *urb)
+{
+	struct usb_mixer_interface *mixer = urb->context;
+	int len = urb->actual_length;
+	int ustatus = urb->status;
+
+	if (ustatus != 0)
+		goto requeue;
+
+	if (mixer->protocol == UAC_VERSION_1) {
+		struct uac1_status_word *status;
+
+		for (status = urb->transfer_buffer;
+		     len >= sizeof(*status);
+		     len -= sizeof(*status), status++) {
+			dev_dbg(&urb->dev->dev, "status interrupt: %02x %02x\n",
+						status->bStatusType,
+						status->bOriginator);
+
+			/* ignore any notifications not from the control interface */
+			if ((status->bStatusType & UAC1_STATUS_TYPE_ORIG_MASK) !=
+				UAC1_STATUS_TYPE_ORIG_AUDIO_CONTROL_IF)
+				continue;
+
+			if (status->bStatusType & UAC1_STATUS_TYPE_MEM_CHANGED)
+				snd_usb_mixer_rc_memory_change(mixer, status->bOriginator);
+			else
+				snd_usb_mixer_notify_id(mixer, status->bOriginator);
+		}
+	} else { /* UAC_VERSION_2 */
+		struct uac2_interrupt_data_msg *msg;
+
+		for (msg = urb->transfer_buffer;
+		     len >= sizeof(*msg);
+		     len -= sizeof(*msg), msg++) {
+			/* drop vendor specific and endpoint requests */
+			if ((msg->bInfo & UAC2_INTERRUPT_DATA_MSG_VENDOR) ||
+			    (msg->bInfo & UAC2_INTERRUPT_DATA_MSG_EP))
+				continue;
+
+			snd_usb_mixer_interrupt_v2(mixer, msg->bAttribute,
+						   le16_to_cpu(msg->wValue),
+						   le16_to_cpu(msg->wIndex));
+		}
+	}
+
+requeue:
+	if (ustatus != -ENOENT &&
+	    ustatus != -ECONNRESET &&
+	    ustatus != -ESHUTDOWN) {
+		urb->dev = mixer->chip->dev;
+		usb_submit_urb(urb, GFP_ATOMIC);
+	}
+}
+
+/* create the handler for the optional status interrupt endpoint */
+static int snd_usb_mixer_status_create(struct usb_mixer_interface *mixer)
+{
+	struct usb_endpoint_descriptor *ep;
+	void *transfer_buffer;
+	int buffer_length;
+	unsigned int epnum;
+
+	/* we need one interrupt input endpoint */
+	if (get_iface_desc(mixer->hostif)->bNumEndpoints < 1)
+		return 0;
+	ep = get_endpoint(mixer->hostif, 0);
+	if (!usb_endpoint_dir_in(ep) || !usb_endpoint_xfer_int(ep))
+		return 0;
+
+	epnum = usb_endpoint_num(ep);
+	buffer_length = le16_to_cpu(ep->wMaxPacketSize);
+	transfer_buffer = kmalloc(buffer_length, GFP_KERNEL);
+	if (!transfer_buffer)
+		return -ENOMEM;
+	mixer->urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!mixer->urb) {
+		kfree(transfer_buffer);
+		return -ENOMEM;
+	}
+	usb_fill_int_urb(mixer->urb, mixer->chip->dev,
+			 usb_rcvintpipe(mixer->chip->dev, epnum),
+			 transfer_buffer, buffer_length,
+			 snd_usb_mixer_interrupt, mixer, ep->bInterval);
+	usb_submit_urb(mixer->urb, GFP_KERNEL);
+	return 0;
+}
+
+int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif)
+{
+	static const struct snd_device_ops dev_ops = {
+		.dev_free = snd_usb_mixer_dev_free
+	};
+	struct usb_mixer_interface *mixer;
+	int err;
+
+	strscpy(chip->card->mixername, "USB Mixer");
+
+	mixer = kzalloc_obj(*mixer);
+	if (!mixer)
+		return -ENOMEM;
+	mixer->chip = chip;
+	mixer->ignore_ctl_error = !!(chip->quirk_flags & QUIRK_FLAG_IGNORE_CTL_ERROR);
+	mixer->id_elems = kzalloc_objs(*mixer->id_elems, MAX_ID_ELEMS);
+	if (!mixer->id_elems) {
+		kfree(mixer);
+		return -ENOMEM;
+	}
+
+	mixer->hostif = &usb_ifnum_to_if(chip->dev, ctrlif)->altsetting[0];
+	switch (get_iface_desc(mixer->hostif)->bInterfaceProtocol) {
+	case UAC_VERSION_1:
+	default:
+		mixer->protocol = UAC_VERSION_1;
+		break;
+	case UAC_VERSION_2:
+		mixer->protocol = UAC_VERSION_2;
+		break;
+	case UAC_VERSION_3:
+		mixer->protocol = UAC_VERSION_3;
+		break;
+	}
+
+	if (mixer->protocol == UAC_VERSION_3 &&
+			chip->badd_profile >= UAC3_FUNCTION_SUBCLASS_GENERIC_IO) {
+		err = snd_usb_mixer_controls_badd(mixer, ctrlif);
+		if (err < 0)
+			goto _error;
+	} else {
+		err = snd_usb_mixer_controls(mixer);
+		if (err < 0)
+			goto _error;
+	}
+
+	err = snd_usb_mixer_status_create(mixer);
+	if (err < 0)
+		goto _error;
+
+	err = snd_usb_mixer_apply_create_quirk(mixer);
+	if (err < 0)
+		goto _error;
+
+	err = snd_device_new(chip->card, SNDRV_DEV_CODEC, mixer, &dev_ops);
+	if (err < 0)
+		goto _error;
+
+	if (list_empty(&chip->mixer_list))
+		snd_card_ro_proc_new(chip->card, "usbmixer", chip,
+				     snd_usb_mixer_proc_read);
+
+	list_add(&mixer->list, &chip->mixer_list);
+	return 0;
+
+_error:
+	snd_usb_mixer_free(mixer);
+	return err;
+}
+
+void snd_usb_mixer_disconnect(struct usb_mixer_interface *mixer)
+{
+	if (mixer->disconnected)
+		return;
+	if (mixer->urb)
+		usb_kill_urb(mixer->urb);
+	if (mixer->rc_urb)
+		usb_kill_urb(mixer->rc_urb);
+	if (mixer->private_free)
+		mixer->private_free(mixer);
+	mixer->disconnected = true;
+}
+
+/* stop any bus activity of a mixer */
+static void snd_usb_mixer_inactivate(struct usb_mixer_interface *mixer)
+{
+	usb_kill_urb(mixer->urb);
+	usb_kill_urb(mixer->rc_urb);
+}
+
+static int snd_usb_mixer_activate(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	if (mixer->urb) {
+		err = usb_submit_urb(mixer->urb, GFP_NOIO);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer)
+{
+	snd_usb_mixer_inactivate(mixer);
+	if (mixer->private_suspend)
+		mixer->private_suspend(mixer);
+	return 0;
+}
+
+static int restore_mixer_value(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
+	int c, err, idx;
+
+	if (cval->val_type == USB_MIXER_BESPOKEN)
+		return 0;
+
+	if (cval->cmask) {
+		idx = 0;
+		for (c = 0; c < MAX_CHANNELS; c++) {
+			if (!(cval->cmask & BIT(c)))
+				continue;
+			if (cval->cached & BIT(c + 1)) {
+				err = snd_usb_set_cur_mix_value(cval, c + 1, idx,
+							cval->cache_val[idx]);
+				if (err < 0)
+					break;
+			}
+			idx++;
+		}
+	} else {
+		/* master */
+		if (cval->cached)
+			snd_usb_set_cur_mix_value(cval, 0, 0, *cval->cache_val);
+	}
+
+	return 0;
+}
+
+int snd_usb_mixer_resume(struct usb_mixer_interface *mixer)
+{
+	struct usb_mixer_elem_list *list;
+	int id, err;
+
+	if (mixer->private_resume) {
+		err = mixer->private_resume(mixer);
+		if (err < 0)
+			return err;
+	}
+
+	/* restore cached mixer values */
+	for (id = 0; id < MAX_ID_ELEMS; id++) {
+		for_each_mixer_elem(list, mixer, id) {
+			if (list->resume) {
+				err = list->resume(list);
+				if (err < 0)
+					return err;
+			}
+		}
+	}
+
+	snd_usb_mixer_resume_quirk(mixer);
+
+	return snd_usb_mixer_activate(mixer);
+}
+
+void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list,
+				 struct usb_mixer_interface *mixer,
+				 int unitid)
+{
+	list->mixer = mixer;
+	list->id = unitid;
+	list->dump = snd_usb_mixer_dump_cval;
+	list->resume = restore_mixer_value;
+}
diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
new file mode 100644
index 000000000..037b446d8
--- /dev/null
+++ b/sound/usb/mixer.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBMIXER_H
+#define __USBMIXER_H
+
+#include <sound/info.h>
+
+struct media_mixer_ctl;
+
+struct usbmix_connector_map {
+	u8 id;
+	u8 delegated_id;
+	u8 control;
+	u8 channel;
+};
+
+struct usb_mixer_interface {
+	struct snd_usb_audio *chip;
+	struct usb_host_interface *hostif;
+	struct list_head list;
+	unsigned int ignore_ctl_error;
+	/* UAC2 status interrupt endpoint; owned by mixer.c */
+	struct urb *urb;
+	/* array[MAX_ID_ELEMS], indexed by unit id */
+	struct usb_mixer_elem_list **id_elems;
+
+	/* the usb audio specification version this interface complies to */
+	int protocol;
+
+	/* optional connector delegation map */
+	const struct usbmix_connector_map *connector_map;
+
+	/* Sound Blaster remote control stuff */
+	const struct rc_config *rc_cfg;
+	u32 rc_code;
+	wait_queue_head_t rc_waitq;
+	struct urb *rc_urb;
+	struct usb_ctrlrequest *rc_setup_packet;
+	u8 rc_buffer[6];
+	struct media_mixer_ctl *media_mixer_ctl;
+
+	bool disconnected;
+
+	void *private_data;
+	void (*private_free)(struct usb_mixer_interface *mixer);
+	void (*private_suspend)(struct usb_mixer_interface *mixer);
+	int (*private_resume)(struct usb_mixer_interface *mixer);
+};
+
+#define MAX_CHANNELS	64	/* max logical channels */
+
+enum {
+	USB_MIXER_BOOLEAN,
+	USB_MIXER_INV_BOOLEAN,
+	USB_MIXER_S8,
+	USB_MIXER_U8,
+	USB_MIXER_S16,
+	USB_MIXER_U16,
+	USB_MIXER_S32,
+	USB_MIXER_U32,
+	USB_MIXER_BESPOKEN,	/* non-standard type */
+};
+
+typedef void (*usb_mixer_elem_dump_func_t)(struct snd_info_buffer *buffer,
+					 struct usb_mixer_elem_list *list);
+typedef int (*usb_mixer_elem_resume_func_t)(struct usb_mixer_elem_list *elem);
+
+struct usb_mixer_elem_list {
+	struct usb_mixer_interface *mixer;
+	struct usb_mixer_elem_list *next_id_elem; /* list of controls with same id */
+	struct snd_kcontrol *kctl;
+	unsigned int id;
+	bool is_std_info;
+	usb_mixer_elem_dump_func_t dump;
+	usb_mixer_elem_resume_func_t resume;
+};
+
+/* iterate over mixer element list of the given unit id */
+#define for_each_mixer_elem(list, mixer, id)	\
+	for ((list) = (mixer)->id_elems[id]; (list); (list) = (list)->next_id_elem)
+#define mixer_elem_list_to_info(list) \
+	container_of(list, struct usb_mixer_elem_info, head)
+
+struct usb_mixer_elem_info {
+	struct usb_mixer_elem_list head;
+	unsigned int control;	/* CS or ICN (high byte) */
+	u64 cmask; /* channel mask bitmap: 0 = master */
+	unsigned int idx_off; /* Control index offset */
+	unsigned int ch_readonly;
+	unsigned int master_readonly;
+	int channels;
+	int val_type;
+	int min, max, res;
+	int max_exposed; /* control API exposes the value in 0..max_exposed */
+	int dBmin, dBmax;
+	int cached;
+	int cache_val[MAX_CHANNELS];
+	u8 initialized;
+	u8 min_mute;
+	u8 get_cur_broken;
+	void *private_data;
+};
+
+int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif);
+void snd_usb_mixer_disconnect(struct usb_mixer_interface *mixer);
+
+void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid);
+
+int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
+				int request, int validx, int value_set);
+
+int snd_usb_mixer_add_list(struct usb_mixer_elem_list *list,
+			   struct snd_kcontrol *kctl,
+			   bool is_std_info);
+
+#define snd_usb_mixer_add_control(list, kctl) \
+	snd_usb_mixer_add_list(list, kctl, true)
+
+void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list,
+				 struct usb_mixer_interface *mixer,
+				 int unitid);
+
+int snd_usb_mixer_vol_tlv(struct snd_kcontrol *kcontrol, int op_flag,
+			  unsigned int size, unsigned int __user *_tlv);
+
+int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer);
+int snd_usb_mixer_resume(struct usb_mixer_interface *mixer);
+
+int snd_usb_set_cur_mix_value(struct usb_mixer_elem_info *cval, int channel,
+                             int index, int value);
+
+int snd_usb_get_cur_mix_value(struct usb_mixer_elem_info *cval,
+                             int channel, int index, int *value);
+
+extern void snd_usb_mixer_elem_free(struct snd_kcontrol *kctl);
+
+extern const struct snd_kcontrol_new *snd_usb_feature_unit_ctl;
+
+#endif /* __USBMIXER_H */
diff --git a/sound/usb/mixer_maps.c b/sound/usb/mixer_maps.c
new file mode 100644
index 000000000..f8e1f7803
--- /dev/null
+++ b/sound/usb/mixer_maps.c
@@ -0,0 +1,857 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Additional mixer mapping
+ *
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
+ */
+
+struct usbmix_dB_map {
+	int min;
+	int max;
+	bool min_mute;
+};
+
+struct usbmix_name_map {
+	int id;
+	const char *name;
+	int control;
+	const struct usbmix_dB_map *dB;
+};
+
+struct usbmix_selector_map {
+	int id;
+	int count;
+	const char **names;
+};
+
+struct usbmix_ctl_map {
+	u32 id;
+	const struct usbmix_name_map *map;
+	const struct usbmix_selector_map *selector_map;
+	const struct usbmix_connector_map *connector_map;
+};
+
+/*
+ * USB control mappers for SB Exitigy
+ */
+
+/*
+ * Topology of SB Extigy (see on the wide screen :)
+
+USB_IN[1] --->FU[2]------------------------------+->MU[16]-->PU[17]-+->FU[18]--+->EU[27]--+->EU[21]-->FU[22]--+->FU[23] > Dig_OUT[24]
+                                                 ^                  |          |          |                   |
+USB_IN[3] -+->SU[5]-->FU[6]--+->MU[14] ->PU[15]->+                  |          |          |                   +->FU[25] > Dig_OUT[26]
+           ^                 ^                   |                  |          |          |
+Dig_IN[4] -+                 |                   |                  |          |          +->FU[28]---------------------> Spk_OUT[19]
+                             |                   |                  |          |
+Lin-IN[7] -+-->FU[8]---------+                   |                  |          +----------------------------------------> Hph_OUT[20]
+           |                                     |                  |
+Mic-IN[9] --+->FU[10]----------------------------+                  |
+           ||                                                       |
+           ||  +----------------------------------------------------+
+           VV  V
+           ++--+->SU[11]-->FU[12] --------------------------------------------------------------------------------------> USB_OUT[13]
+*/
+
+static const struct usbmix_name_map extigy_map[] = {
+	/* 1: IT pcm */
+	{ 2, "PCM Playback" }, /* FU */
+	/* 3: IT pcm */
+	/* 4: IT digital in */
+	{ 5, NULL }, /* DISABLED: this seems to be bogus on some firmware */
+	{ 6, "Digital In" }, /* FU */
+	/* 7: IT line */
+	{ 8, "Line Playback" }, /* FU */
+	/* 9: IT mic */
+	{ 10, "Mic Playback" }, /* FU */
+	{ 11, "Capture Source" }, /* SU */
+	{ 12, "Capture" }, /* FU */
+	/* 13: OT pcm capture */
+	/* 14: MU (w/o controls) */
+	/* 15: PU (3D enh) */
+	/* 16: MU (w/o controls) */
+	{ 17, NULL, 1 }, /* DISABLED: PU-switch (any effect?) */
+	{ 17, "Channel Routing", 2 },	/* PU: mode select */
+	{ 18, "Tone Control - Bass", UAC_FU_BASS }, /* FU */
+	{ 18, "Tone Control - Treble", UAC_FU_TREBLE }, /* FU */
+	{ 18, "Master Playback" }, /* FU; others */
+	/* 19: OT speaker */
+	/* 20: OT headphone */
+	{ 21, NULL }, /* DISABLED: EU (for what?) */
+	{ 22, "Digital Out Playback" }, /* FU */
+	{ 23, "Digital Out1 Playback" }, /* FU */  /* FIXME: corresponds to 24 */
+	/* 24: OT digital out */
+	{ 25, "IEC958 Optical Playback" }, /* FU */
+	{ 26, "IEC958 Optical Playback" }, /* OT */
+	{ 27, NULL }, /* DISABLED: EU (for what?) */
+	/* 28: FU speaker (mute) */
+	{ 29, NULL }, /* Digital Input Playback Source? */
+	{ 0 } /* terminator */
+};
+
+/* Sound Blaster MP3+ controls mapping
+ * The default mixer channels have totally misleading names,
+ * e.g. no Master and fake PCM volume
+ *			Pavel Mihaylov <bin@bash.info>
+ */
+static const struct usbmix_dB_map mp3plus_dB_1 = {.min = -4781, .max = 0};
+						/* just guess */
+static const struct usbmix_dB_map mp3plus_dB_2 = {.min = -1781, .max = 618};
+						/* just guess */
+
+static const struct usbmix_name_map mp3plus_map[] = {
+	/* 1: IT pcm */
+	/* 2: IT mic */
+	/* 3: IT line */
+	/* 4: IT digital in */
+	/* 5: OT digital out */
+	/* 6: OT speaker */
+	/* 7: OT pcm capture */
+	{ 8, "Capture Source" }, /* FU, default PCM Capture Source */
+		/* (Mic, Input 1 = Line input, Input 2 = Optical input) */
+	{ 9, "Master Playback" }, /* FU, default Speaker 1 */
+	/* { 10, "Mic Capture", 1 }, */ /* FU, Mic Capture */
+	{ 10, /* "Mic Capture", */ NULL, 2, .dB = &mp3plus_dB_2 },
+		/* FU, Mic Capture */
+	{ 10, "Mic Boost", 7 }, /* FU, default Auto Gain Input */
+	{ 11, "Line Capture", .dB = &mp3plus_dB_2 },
+		/* FU, default PCM Capture */
+	{ 12, "Digital In Playback" }, /* FU, default PCM 1 */
+	{ 13, /* "Mic Playback", */ .dB = &mp3plus_dB_1 },
+		/* FU, default Mic Playback */
+	{ 14, "Line Playback", .dB = &mp3plus_dB_1 }, /* FU, default Speaker */
+	/* 15: MU */
+	{ 0 } /* terminator */
+};
+
+/* Topology of SB Audigy 2 NX
+
+          +----------------------------->EU[27]--+
+          |                                      v
+          | +----------------------------------->SU[29]---->FU[22]-->Dig_OUT[24]
+          | |                                    ^
+USB_IN[1]-+------------+              +->EU[17]->+->FU[11]-+
+            |          v              |          v         |
+Dig_IN[4]---+->FU[6]-->MU[16]->FU[18]-+->EU[21]->SU[31]----->FU[30]->Hph_OUT[20]
+            |          ^              |                    |
+Lin_IN[7]-+--->FU[8]---+              +->EU[23]->FU[28]------------->Spk_OUT[19]
+          | |                                              v
+          +--->FU[12]------------------------------------->SU[14]--->USB_OUT[15]
+            |                                              ^
+            +->FU[13]--------------------------------------+
+*/
+static const struct usbmix_name_map audigy2nx_map[] = {
+	/* 1: IT pcm playback */
+	/* 4: IT digital in */
+	{ 6, "Digital In Playback" }, /* FU */
+	/* 7: IT line in */
+	{ 8, "Line Playback" }, /* FU */
+	{ 11, "What-U-Hear Capture" }, /* FU */
+	{ 12, "Line Capture" }, /* FU */
+	{ 13, "Digital In Capture" }, /* FU */
+	{ 14, "Capture Source" }, /* SU */
+	/* 15: OT pcm capture */
+	/* 16: MU w/o controls */
+	{ 17, NULL }, /* DISABLED: EU (for what?) */
+	{ 18, "Master Playback" }, /* FU */
+	/* 19: OT speaker */
+	/* 20: OT headphone */
+	{ 21, NULL }, /* DISABLED: EU (for what?) */
+	{ 22, "Digital Out Playback" }, /* FU */
+	{ 23, NULL }, /* DISABLED: EU (for what?) */
+	/* 24: OT digital out */
+	{ 27, NULL }, /* DISABLED: EU (for what?) */
+	{ 28, "Speaker Playback" }, /* FU */
+	{ 29, "Digital Out Source" }, /* SU */
+	{ 30, "Headphone Playback" }, /* FU */
+	{ 31, "Headphone Source" }, /* SU */
+	{ 0 } /* terminator */
+};
+
+static const struct usbmix_name_map mbox1_map[] = {
+	{ 1, "Clock" },
+	{ 0 } /* terminator */
+};
+
+static const struct usbmix_selector_map c400_selectors[] = {
+	{
+		.id = 0x80,
+		.count = 2,
+		.names = (const char*[]) {"Internal", "SPDIF"}
+	},
+	{ 0 } /* terminator */
+};
+
+static const struct usbmix_selector_map audigy2nx_selectors[] = {
+	{
+		.id = 14, /* Capture Source */
+		.count = 3,
+		.names = (const char*[]) {"Line", "Digital In", "What-U-Hear"}
+	},
+	{
+		.id = 29, /* Digital Out Source */
+		.count = 3,
+		.names = (const char*[]) {"Front", "PCM", "Digital In"}
+	},
+	{
+		.id = 31, /* Headphone Source */
+		.count = 2,
+		.names = (const char*[]) {"Front", "Side"}
+	},
+	{ 0 } /* terminator */
+};
+
+/* Creative SoundBlaster Live! 24-bit External */
+static const struct usbmix_name_map live24ext_map[] = {
+	/* 2: PCM Playback Volume */
+	{ 5, "Mic Capture" }, /* FU, default PCM Capture Volume */
+	{ 0 } /* terminator */
+};
+
+/* LineX FM Transmitter entry - needed to bypass controls bug */
+static const struct usbmix_name_map linex_map[] = {
+	/* 1: IT pcm */
+	/* 2: OT Speaker */ 
+	{ 3, "Master" }, /* FU: master volume - left / right / mute */
+	{ 0 } /* terminator */
+};
+
+static const struct usbmix_name_map maya44_map[] = {
+	/* 1: IT line */
+	{ 2, "Line Playback" }, /* FU */
+	/* 3: IT line */
+	{ 4, "Line Playback" }, /* FU */
+	/* 5: IT pcm playback */
+	/* 6: MU */
+	{ 7, "Master Playback" }, /* FU */
+	/* 8: OT speaker */
+	/* 9: IT line */
+	{ 10, "Line Capture" }, /* FU */
+	/* 11: MU */
+	/* 12: OT pcm capture */
+	{ }
+};
+
+/* Section "justlink_map" below added by James Courtier-Dutton <James@superbug.demon.co.uk>
+ * sourced from Maplin Electronics (https://www.maplin.co.uk), part number A56AK
+ * Part has 2 connectors that act as a single output. (TOSLINK Optical for digital out, and 3.5mm Jack for Analogue out.)
+ * The USB Mixer publishes a Microphone and extra Volume controls for it, but none exist on the device,
+ * so this map removes all unwanted sliders from alsamixer
+ */
+
+static const struct usbmix_name_map justlink_map[] = {
+	/* 1: IT pcm playback */
+	/* 2: Not present */
+	{ 3, NULL}, /* IT mic (No mic input on device) */
+	/* 4: Not present */
+	/* 5: OT speacker */
+	/* 6: OT pcm capture */
+	{ 7, "Master Playback" }, /* Mute/volume for speaker */
+	{ 8, NULL }, /* Capture Switch (No capture inputs on device) */
+	{ 9, NULL }, /* Capture Mute/volume (No capture inputs on device */
+	/* 0xa: Not present */
+	/* 0xb: MU (w/o controls) */
+	{ 0xc, NULL }, /* Mic feedback Mute/volume (No capture inputs on device) */
+	{ 0 } /* terminator */
+};
+
+/* TerraTec Aureon 5.1 MkII USB */
+static const struct usbmix_name_map aureon_51_2_map[] = {
+	/* 1: IT USB */
+	/* 2: IT Mic */
+	/* 3: IT Line */
+	/* 4: IT SPDIF */
+	/* 5: OT SPDIF */
+	/* 6: OT Speaker */
+	/* 7: OT USB */
+	{ 8, "Capture Source" }, /* SU */
+	{ 9, "Master Playback" }, /* FU */
+	{ 10, "Mic Capture" }, /* FU */
+	{ 11, "Line Capture" }, /* FU */
+	{ 12, "IEC958 In Capture" }, /* FU */
+	{ 13, "Mic Playback" }, /* FU */
+	{ 14, "Line Playback" }, /* FU */
+	/* 15: MU */
+	{} /* terminator */
+};
+
+static const struct usbmix_name_map scratch_live_map[] = {
+	/* 1: IT Line 1 (USB streaming) */
+	/* 2: OT Line 1 (Speaker) */
+	/* 3: IT Line 1 (Line connector) */
+	{ 4, "Line 1 In" }, /* FU */
+	/* 5: OT Line 1 (USB streaming) */
+	/* 6: IT Line 2 (USB streaming) */
+	/* 7: OT Line 2 (Speaker) */
+	/* 8: IT Line 2 (Line connector) */
+	{ 9, "Line 2 In" }, /* FU */
+	/* 10: OT Line 2 (USB streaming) */
+	/* 11: IT Mic (Line connector) */
+	/* 12: OT Mic (USB streaming) */
+	{ 0 } /* terminator */
+};
+
+static const struct usbmix_name_map ebox44_map[] = {
+	{ 4, NULL }, /* FU */
+	{ 6, NULL }, /* MU */
+	{ 7, NULL }, /* FU */
+	{ 10, NULL }, /* FU */
+	{ 11, NULL }, /* MU */
+	{ 0 }
+};
+
+/* "Gamesurround Muse Pocket LT" looks same like "Sound Blaster MP3+"
+ *  most importand difference is SU[8], it should be set to "Capture Source"
+ *  to make alsamixer and PA working properly.
+ *  FIXME: or mp3plus_map should use "Capture Source" too,
+ *  so this maps can be merget
+ */
+static const struct usbmix_name_map hercules_usb51_map[] = {
+	{ 8, "Capture Source" },	/* SU, default "PCM Capture Source" */
+	{ 9, "Master Playback" },	/* FU, default "Speaker Playback" */
+	{ 10, "Mic Boost", 7 },		/* FU, default "Auto Gain Input" */
+	{ 11, "Line Capture" },		/* FU, default "PCM Capture" */
+	{ 13, "Mic Bypass Playback" },	/* FU, default "Mic Playback" */
+	{ 14, "Line Bypass Playback" },	/* FU, default "Line Playback" */
+	{ 0 }				/* terminator */
+};
+
+/* Plantronics Gamecom 780 has a broken volume control, better to disable it */
+static const struct usbmix_name_map gamecom780_map[] = {
+	{ 9, NULL }, /* FU, speaker out */
+	{}
+};
+
+/* some (all?) SCMS USB3318 devices are affected by a firmware lock up
+ * when anything attempts to access FU 10 (control)
+ */
+static const struct usbmix_name_map scms_usb3318_map[] = {
+	{ 10, NULL },
+	{ 0 }
+};
+
+/* Bose companion 5, the dB conversion factor is 16 instead of 256 */
+static const struct usbmix_dB_map bose_companion5_dB = {-5006, -6};
+static const struct usbmix_name_map bose_companion5_map[] = {
+	{ 3, NULL, .dB = &bose_companion5_dB },
+	{ 0 }	/* terminator */
+};
+
+/* Bose Revolve+ SoundLink, correction of dB maps */
+static const struct usbmix_dB_map bose_soundlink_dB = {-8283, -0, true};
+static const struct usbmix_name_map bose_soundlink_map[] = {
+	{ 2, NULL, .dB = &bose_soundlink_dB },
+	{ 0 }	/* terminator */
+};
+
+/*
+ * Razer Barracuda X 2.4: Firmware reports cval->min = -16800 in 1/256 dB units
+ * (-65.62 dB), which stock ALSA misinterprets as a -168 dB floor
+ */
+static const struct usbmix_dB_map razer_barracuda_x_2_4_dB = {-6562, 0};
+static const struct usbmix_name_map razer_barracuda_x_2_4_map[] = {
+	{ 2, NULL, .dB = &razer_barracuda_x_2_4_dB },
+	{ 0 }   /* terminator */
+};
+
+/* Sennheiser Communications Headset [PC 8], the dB value is reported as -6 negative maximum  */
+static const struct usbmix_dB_map sennheiser_pc8_dB = {-9500, 0};
+static const struct usbmix_name_map sennheiser_pc8_map[] = {
+	{ 9, NULL, .dB = &sennheiser_pc8_dB },
+	{ 0 }   /* terminator */
+};
+
+/*
+ * Dell usb dock with ALC4020 codec had a firmware problem where it got
+ * screwed up when zero volume is passed; just skip it as a workaround
+ *
+ * Also the extension unit gives an access error, so skip it as well.
+ */
+static const struct usbmix_name_map dell_alc4020_map[] = {
+	{ 4, NULL },	/* extension unit */
+	{ 16, NULL },
+	{ 19, NULL },
+	{ 0 }
+};
+
+/*
+ * Corsair Virtuoso calls everything "Headset" without this, leading to
+ * applications moving the sidetone control instead of the main one.
+ */
+static const struct usbmix_name_map corsair_virtuoso_map[] = {
+	{ 3, "Mic Capture" },
+	{ 6, "Sidetone Playback" },
+	{ 0 }
+};
+
+/* Microsoft USB Link headset */
+/* a guess work: raw playback volume values are from 2 to 129 */
+static const struct usbmix_dB_map ms_usb_link_dB = { -3225, 0, true };
+static const struct usbmix_name_map ms_usb_link_map[] = {
+	{ 9, NULL, .dB = &ms_usb_link_dB },
+	{ 10, NULL }, /* Headset Capture volume; seems non-working, disabled */
+	{ 0 }   /* terminator */
+};
+
+/* KTMicro USB */
+static struct usbmix_name_map s31b2_0022_map[] = {
+	{ 23, "Speaker Playback" },
+	{ 18, "Headphone Playback" },
+	{ 0 }
+};
+
+/* ASUS ROG Zenith II with Realtek ALC1220-VB */
+static const struct usbmix_name_map asus_zenith_ii_map[] = {
+	{ 19, NULL, 12 }, /* FU, Input Gain Pad - broken response, disabled */
+	{ 16, "Speaker" },		/* OT */
+	{ 22, "Speaker Playback" },	/* FU */
+	{ 7, "Line" },			/* IT */
+	{ 19, "Line Capture" },		/* FU */
+	{ 8, "Mic" },			/* IT */
+	{ 20, "Mic Capture" },		/* FU */
+	{ 9, "Front Mic" },		/* IT */
+	{ 21, "Front Mic Capture" },	/* FU */
+	{ 17, "IEC958" },		/* OT */
+	{ 23, "IEC958 Playback" },	/* FU */
+	{}
+};
+
+static const struct usbmix_connector_map asus_zenith_ii_connector_map[] = {
+	{ 10, 16 },	/* (Back) Speaker */
+	{ 11, 17 },	/* SPDIF */
+	{ 13, 7 },	/* Line */
+	{ 14, 8 },	/* Mic */
+	{ 15, 9 },	/* Front Mic */
+	{}
+};
+
+static const struct usbmix_name_map lenovo_p620_rear_map[] = {
+	{ 19, NULL, 12 }, /* FU, Input Gain Pad */
+	{}
+};
+
+/* TRX40 mobos with Realtek ALC1220-VB */
+static const struct usbmix_name_map trx40_mobo_map[] = {
+	{ 18, NULL }, /* OT, IEC958 - broken response, disabled */
+	{ 19, NULL, 12 }, /* FU, Input Gain Pad - broken response, disabled */
+	{ 16, "Speaker" },		/* OT */
+	{ 22, "Speaker Playback" },	/* FU */
+	{ 7, "Line" },			/* IT */
+	{ 19, "Line Capture" },		/* FU */
+	{ 17, "Front Headphone" },	/* OT */
+	{ 23, "Front Headphone Playback" },	/* FU */
+	{ 8, "Mic" },			/* IT */
+	{ 20, "Mic Capture" },		/* FU */
+	{ 9, "Front Mic" },		/* IT */
+	{ 21, "Front Mic Capture" },	/* FU */
+	{ 24, "IEC958 Playback" },	/* FU */
+	{}
+};
+
+static const struct usbmix_connector_map trx40_mobo_connector_map[] = {
+	{ 10, 16 },	/* (Back) Speaker */
+	{ 11, 17 },	/* Front Headphone */
+	{ 13, 7 },	/* Line */
+	{ 14, 8 },	/* Mic */
+	{ 15, 9 },	/* Front Mic */
+	{}
+};
+
+/* Rear panel + front mic on Gigabyte TRX40 Aorus Master with ALC1220-VB */
+static const struct usbmix_name_map aorus_master_alc1220vb_map[] = {
+	{ 17, NULL },			/* OT, IEC958?, disabled */
+	{ 19, NULL, 12 }, /* FU, Input Gain Pad - broken response, disabled */
+	{ 16, "Line Out" },		/* OT */
+	{ 22, "Line Out Playback" },	/* FU */
+	{ 7, "Line" },			/* IT */
+	{ 19, "Line Capture" },		/* FU */
+	{ 8, "Mic" },			/* IT */
+	{ 20, "Mic Capture" },		/* FU */
+	{ 9, "Front Mic" },		/* IT */
+	{ 21, "Front Mic Capture" },	/* FU */
+	{}
+};
+
+/* MSI MPG X570S Carbon Max Wifi with ALC4080  */
+static const struct usbmix_name_map msi_mpg_x570s_carbon_max_wifi_alc4080_map[] = {
+	{ 29, "Speaker Playback" },
+	{ 30, "Front Headphone Playback" },
+	{ 32, "IEC958 Playback" },
+	{}
+};
+
+/* Gigabyte B450/550 Mobo */
+static const struct usbmix_name_map gigabyte_b450_map[] = {
+	{ 24, NULL },			/* OT, IEC958?, disabled */
+	{ 21, "Speaker" },		/* OT */
+	{ 29, "Speaker Playback" },	/* FU */
+	{ 22, "Headphone" },		/* OT */
+	{ 30, "Headphone Playback" },	/* FU */
+	{ 11, "Line" },			/* IT */
+	{ 27, "Line Capture" },		/* FU */
+	{ 12, "Mic" },			/* IT */
+	{ 28, "Mic Capture" },		/* FU */
+	{ 9, "Front Mic" },		/* IT */
+	{ 25, "Front Mic Capture" },	/* FU */
+	{}
+};
+
+static const struct usbmix_connector_map gigabyte_b450_connector_map[] = {
+	{ 13, 21 },	/* Speaker */
+	{ 14, 22 },	/* Headphone */
+	{ 19, 11 },	/* Line */
+	{ 20, 12 },	/* Mic */
+	{ 17, 9 },	/* Front Mic */
+	{}
+};
+
+/* Audient iD14 MkI and MkII: FU 12 sits on the monitor mixer branch but is
+ * traced through to the Speaker output terminal, so it is named "Speaker
+ * Playback Volume".  On MkII it controls only 4 of 6 playback channels.  MkI
+ * testing found asymmetric attenuation within the main stereo pair.  Userspace
+ * adopts this control as the stream's hardware volume, causing imbalance below
+ * 0 dB.  Give it a non-standard name so that userspace no longer treats it as
+ * the stream master, while keeping the monitor gain reachable.
+ */
+static const struct usbmix_name_map audient_id14_map[] = {
+	{ 12, "Monitor Mix Playback" },	/* FU, partial coverage */
+	{}
+};
+
+/*
+ * Audient iD24: feature unit 12 ("Speaker Playback Volume") sits in the
+ * monitor-mixer branch and does not apply volume to all of its channels;
+ * when userspace adopts it as the master playback volume, the left main
+ * output stays at 0 dB while the right one is attenuated, producing a
+ * stereo imbalance.  Rename it so that it is not picked up as the
+ * stream's master volume control.
+ */
+static const struct usbmix_name_map audient_id24_map[] = {
+	{ 12, "Monitor Mix Playback" },	/* FU, partial channel coverage */
+	{}
+};
+
+/*
+ * The GC553Pro returns no data for GET_CUR on its advertised mute control.
+ * SET_CUR succeeds but does not mute capture, so skip the control entirely.
+ */
+static const struct usbmix_name_map avermedia_gc553pro_map[] = {
+	{ 3, NULL, UAC_FU_MUTE },
+	{}
+};
+
+/*
+ * Control map entries
+ */
+
+static const struct usbmix_ctl_map usbmix_ctl_maps[] = {
+	{
+		.id = USB_ID(0x041e, 0x3000),
+		.map = extigy_map,
+	},
+	{
+		.id = USB_ID(0x041e, 0x3010),
+		.map = mp3plus_map,
+	},
+	{
+		.id = USB_ID(0x041e, 0x3020),
+		.map = audigy2nx_map,
+		.selector_map = audigy2nx_selectors,
+	},
+ 	{
+		.id = USB_ID(0x041e, 0x3040),
+		.map = live24ext_map,
+	},
+	{
+		.id = USB_ID(0x041e, 0x3048),
+		.map = audigy2nx_map,
+		.selector_map = audigy2nx_selectors,
+	},
+	{	/* Plantronics GameCom 780 */
+		.id = USB_ID(0x047f, 0xc010),
+		.map = gamecom780_map,
+	},
+	{
+		/* Hercules Gamesurround Muse Pocket LT
+		 * (USB 5.1 Channel Audio Adapter)
+		 */
+		.id = USB_ID(0x06f8, 0xc000),
+		.map = hercules_usb51_map,
+	},
+	{
+		.id = USB_ID(0x0763, 0x2030),
+		.selector_map = c400_selectors,
+	},
+	{
+		.id = USB_ID(0x0763, 0x2031),
+		.selector_map = c400_selectors,
+	},
+	{
+		.id = USB_ID(0x07ca, 0x1553),
+		.map = avermedia_gc553pro_map,
+	},
+	{
+		.id = USB_ID(0x08bb, 0x2702),
+		.map = linex_map,
+	},
+	{
+		.id = USB_ID(0x0a92, 0x0091),
+		.map = maya44_map,
+	},
+	{
+		.id = USB_ID(0x0c45, 0x1158),
+		.map = justlink_map,
+	},
+	{
+		.id = USB_ID(0x0ccd, 0x0028),
+		.map = aureon_51_2_map,
+	},
+	{
+		.id = USB_ID(0x0bda, 0x4014),
+		.map = dell_alc4020_map,
+	},
+	{
+		.id = USB_ID(0x0dba, 0x1000),
+		.map = mbox1_map,
+	},
+	{
+		.id = USB_ID(0x13e5, 0x0001),
+		.map = scratch_live_map,
+	},
+	{
+		.id = USB_ID(0x200c, 0x1018),
+		.map = ebox44_map,
+	},
+	{
+		/* MAYA44 USB+ */
+		.id = USB_ID(0x2573, 0x0008),
+		.map = maya44_map,
+	},
+	{
+		/* Audient iD14 MkI */
+		.id = USB_ID(0x2708, 0x0002),
+		.map = audient_id14_map,
+	},
+	{
+		/* Audient iD14 MkII */
+		.id = USB_ID(0x2708, 0x0008),
+		.map = audient_id14_map,
+	},
+	{
+		/* Audient iD24 */
+		.id = USB_ID(0x2708, 0x000d),
+		.map = audient_id24_map,
+	},
+	{
+		/* KEF X300A */
+		.id = USB_ID(0x27ac, 0x1000),
+		.map = scms_usb3318_map,
+	},
+	{
+		/* Arcam rPAC */
+		.id = USB_ID(0x25c4, 0x0003),
+		.map = scms_usb3318_map,
+	},
+	{
+		/* Bose Companion 5 */
+		.id = USB_ID(0x05a7, 0x1020),
+		.map = bose_companion5_map,
+	},
+	{
+		/* Bose Revolve+ SoundLink */
+		.id = USB_ID(0x05a7, 0x40fa),
+		.map = bose_soundlink_map,
+	},
+	{
+		/* Corsair Virtuoso SE Latest (wired mode) */
+		.id = USB_ID(0x1b1c, 0x0a3f),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair Virtuoso SE Latest (wireless mode) */
+		.id = USB_ID(0x1b1c, 0x0a40),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair Virtuoso SE (wired mode) */
+		.id = USB_ID(0x1b1c, 0x0a3d),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair Virtuoso SE (wireless mode) */
+		.id = USB_ID(0x1b1c, 0x0a3e),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair Virtuoso (wired mode) */
+		.id = USB_ID(0x1b1c, 0x0a41),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair Virtuoso (wireless mode) */
+		.id = USB_ID(0x1b1c, 0x0a42),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair Virtuoso (wired mode, later revision) */
+		.id = USB_ID(0x1b1c, 0x0a43),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair Virtuoso (wireless mode, later revision) */
+		.id = USB_ID(0x1b1c, 0x0a44),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair HS80 RGB Wireless (wired mode) */
+		.id = USB_ID(0x1b1c, 0x0a6a),
+		.map = corsair_virtuoso_map,
+	},
+	{
+		/* Corsair HS80 RGB Wireless (wireless mode) */
+		.id = USB_ID(0x1b1c, 0x0a6b),
+		.map = corsair_virtuoso_map,
+	},
+	{	/* Gigabyte TRX40 Aorus Master (rear panel + front mic) */
+		.id = USB_ID(0x0414, 0xa001),
+		.map = aorus_master_alc1220vb_map,
+	},
+	{	/* Gigabyte TRX40 Aorus Pro WiFi */
+		.id = USB_ID(0x0414, 0xa002),
+		.map = trx40_mobo_map,
+		.connector_map = trx40_mobo_connector_map,
+	},
+	{	/* Gigabyte B450/550 Mobo */
+		.id = USB_ID(0x0414, 0xa00d),
+		.map = gigabyte_b450_map,
+		.connector_map = gigabyte_b450_connector_map,
+	},
+	{	/* ASUS ROG Zenith II (main audio) */
+		.id = USB_ID(0x0b05, 0x1916),
+		.map = asus_zenith_ii_map,
+		.connector_map = asus_zenith_ii_connector_map,
+	},
+	{	/* ASUS ROG Strix */
+		.id = USB_ID(0x0b05, 0x1917),
+		.map = trx40_mobo_map,
+		.connector_map = trx40_mobo_connector_map,
+	},
+	{	/* MSI TRX40 Creator */
+		.id = USB_ID(0x0db0, 0x0d64),
+		.map = trx40_mobo_map,
+		.connector_map = trx40_mobo_connector_map,
+	},
+	{	/* MSI MPG X570S Carbon Max Wifi */
+		.id = USB_ID(0x0db0, 0x419c),
+		.map = msi_mpg_x570s_carbon_max_wifi_alc4080_map,
+	},
+	{	/* MSI MAG X570S Torpedo Max */
+		.id = USB_ID(0x0db0, 0xa073),
+		.map = msi_mpg_x570s_carbon_max_wifi_alc4080_map,
+	},
+	{	/* MSI MAG B850M MORTAR WIFI */
+		.id = USB_ID(0x0db0, 0xcc78),
+		.map = msi_mpg_x570s_carbon_max_wifi_alc4080_map,
+	},
+	{	/* MSI TRX40 */
+		.id = USB_ID(0x0db0, 0x543d),
+		.map = trx40_mobo_map,
+		.connector_map = trx40_mobo_connector_map,
+	},
+	{	/* Asrock TRX40 Creator */
+		.id = USB_ID(0x26ce, 0x0a01),
+		.map = trx40_mobo_map,
+		.connector_map = trx40_mobo_connector_map,
+	},
+	{	/* Lenovo ThinkStation P620 Rear */
+		.id = USB_ID(0x17aa, 0x1046),
+		.map = lenovo_p620_rear_map,
+	},
+	{
+		/* Razer Barracuda X 2.4 */
+		.id = USB_ID(0x1532, 0x0552),
+		.map = razer_barracuda_x_2_4_map,
+	},
+	{
+		/* Sennheiser Communications Headset [PC 8] */
+		.id = USB_ID(0x1395, 0x0025),
+		.map = sennheiser_pc8_map,
+	},
+	{
+		/* Microsoft USB Link headset */
+		.id = USB_ID(0x045e, 0x083c),
+		.map = ms_usb_link_map,
+	},
+	{
+		/* KTMicro USB */
+		.id = USB_ID(0X31b2, 0x0022),
+		.map = s31b2_0022_map,
+	},
+	{ 0 } /* terminator */
+};
+
+/*
+ * Control map entries for UAC3 BADD profiles
+ */
+
+static const struct usbmix_name_map uac3_badd_generic_io_map[] = {
+	{ UAC3_BADD_FU_ID2, "Generic Out Playback" },
+	{ UAC3_BADD_FU_ID5, "Generic In Capture" },
+	{ 0 }					/* terminator */
+};
+static const struct usbmix_name_map uac3_badd_headphone_map[] = {
+	{ UAC3_BADD_FU_ID2, "Headphone Playback" },
+	{ 0 }					/* terminator */
+};
+static const struct usbmix_name_map uac3_badd_speaker_map[] = {
+	{ UAC3_BADD_FU_ID2, "Speaker Playback" },
+	{ 0 }					/* terminator */
+};
+static const struct usbmix_name_map uac3_badd_microphone_map[] = {
+	{ UAC3_BADD_FU_ID5, "Mic Capture" },
+	{ 0 }					/* terminator */
+};
+/* Covers also 'headset adapter' profile */
+static const struct usbmix_name_map uac3_badd_headset_map[] = {
+	{ UAC3_BADD_FU_ID2, "Headset Playback" },
+	{ UAC3_BADD_FU_ID5, "Headset Capture" },
+	{ UAC3_BADD_FU_ID7, "Sidetone Mixing" },
+	{ 0 }					/* terminator */
+};
+static const struct usbmix_name_map uac3_badd_speakerphone_map[] = {
+	{ UAC3_BADD_FU_ID2, "Speaker Playback" },
+	{ UAC3_BADD_FU_ID5, "Mic Capture" },
+	{ 0 }					/* terminator */
+};
+
+static const struct usbmix_ctl_map uac3_badd_usbmix_ctl_maps[] = {
+	{
+		.id = UAC3_FUNCTION_SUBCLASS_GENERIC_IO,
+		.map = uac3_badd_generic_io_map,
+	},
+	{
+		.id = UAC3_FUNCTION_SUBCLASS_HEADPHONE,
+		.map = uac3_badd_headphone_map,
+	},
+	{
+		.id = UAC3_FUNCTION_SUBCLASS_SPEAKER,
+		.map = uac3_badd_speaker_map,
+	},
+	{
+		.id = UAC3_FUNCTION_SUBCLASS_MICROPHONE,
+		.map = uac3_badd_microphone_map,
+	},
+	{
+		.id = UAC3_FUNCTION_SUBCLASS_HEADSET,
+		.map = uac3_badd_headset_map,
+	},
+	{
+		.id = UAC3_FUNCTION_SUBCLASS_HEADSET_ADAPTER,
+		.map = uac3_badd_headset_map,
+	},
+	{
+		.id = UAC3_FUNCTION_SUBCLASS_SPEAKERPHONE,
+		.map = uac3_badd_speakerphone_map,
+	},
+	{ 0 } /* terminator */
+};
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
new file mode 100644
index 000000000..fc622eb95
--- /dev/null
+++ b/sound/usb/mixer_quirks.c
@@ -0,0 +1,4816 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   USB Audio Driver for ALSA
+ *
+ *   Quirks and vendor-specific extensions for mixer interfaces
+ *
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
+ *
+ *   Many codes borrowed from audio.c by
+ *	    Alan Cox (alan@lxorguk.ukuu.org.uk)
+ *	    Thomas Sailer (sailer@ife.ee.ethz.ch)
+ *
+ *   Audio Advantage Micro II support added by:
+ *	    Przemek Rudy (prudy1@o2.pl)
+ */
+
+#include <linux/bitfield.h>
+#include <linux/hid.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/math64.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+
+#include <sound/asoundef.h>
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/hda_verbs.h>
+#include <sound/hwdep.h>
+#include <sound/info.h>
+#include <sound/tlv.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "mixer_quirks.h"
+#include "mixer_scarlett.h"
+#include "mixer_scarlett2.h"
+#include "mixer_us16x08.h"
+#include "mixer_s1810c.h"
+#include "helper.h"
+#include "fcp.h"
+
+struct std_mono_table {
+	unsigned int unitid, control, cmask;
+	int val_type;
+	const char *name;
+	snd_kcontrol_tlv_rw_t *tlv_callback;
+};
+
+/* This function allows for the creation of standard UAC controls.
+ * See the quirks for M-Audio FTUs or Ebox-44.
+ * If you don't want to set a TLV callback pass NULL.
+ *
+ * Since there doesn't seem to be a devices that needs a multichannel
+ * version, we keep it mono for simplicity.
+ */
+static int snd_create_std_mono_ctl_offset(struct usb_mixer_interface *mixer,
+					  unsigned int unitid,
+					  unsigned int control,
+					  unsigned int cmask,
+					  int val_type,
+					  unsigned int idx_off,
+					  const char *name,
+					  snd_kcontrol_tlv_rw_t *tlv_callback)
+{
+	struct usb_mixer_elem_info *cval;
+	struct snd_kcontrol *kctl;
+
+	cval = kzalloc_obj(*cval);
+	if (!cval)
+		return -ENOMEM;
+
+	snd_usb_mixer_elem_init_std(&cval->head, mixer, unitid);
+	cval->val_type = val_type;
+	cval->channels = 1;
+	cval->control = control;
+	cval->cmask = cmask;
+	cval->idx_off = idx_off;
+
+	/* get_min_max() is called only for integer volumes later,
+	 * so provide a short-cut for booleans
+	 */
+	cval->min = 0;
+	cval->max = 1;
+	cval->res = 0;
+	cval->dBmin = 0;
+	cval->dBmax = 0;
+
+	/* Create control */
+	kctl = snd_ctl_new1(snd_usb_feature_unit_ctl, cval);
+	if (!kctl) {
+		kfree(cval);
+		return -ENOMEM;
+	}
+
+	/* Set name */
+	snprintf(kctl->id.name, sizeof(kctl->id.name), name);
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	/* set TLV */
+	if (tlv_callback) {
+		kctl->tlv.c = tlv_callback;
+		kctl->vd[0].access |=
+			SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+			SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+	}
+	/* Add control to mixer */
+	return snd_usb_mixer_add_control(&cval->head, kctl);
+}
+
+static int snd_create_std_mono_ctl(struct usb_mixer_interface *mixer,
+				   unsigned int unitid,
+				   unsigned int control,
+				   unsigned int cmask,
+				   int val_type,
+				   const char *name,
+				   snd_kcontrol_tlv_rw_t *tlv_callback)
+{
+	return snd_create_std_mono_ctl_offset(mixer, unitid, control, cmask,
+					      val_type, 0 /* Offset */,
+					      name, tlv_callback);
+}
+
+/*
+ * Create a set of standard UAC controls from a table
+ */
+static int snd_create_std_mono_table(struct usb_mixer_interface *mixer,
+				     const struct std_mono_table *t)
+{
+	int err;
+
+	while (t->name) {
+		err = snd_create_std_mono_ctl(mixer, t->unitid, t->control,
+					      t->cmask, t->val_type, t->name,
+					      t->tlv_callback);
+		if (err < 0)
+			return err;
+		t++;
+	}
+
+	return 0;
+}
+
+static int add_single_ctl_with_resume(struct usb_mixer_interface *mixer,
+				      int id,
+				      usb_mixer_elem_resume_func_t resume,
+				      const struct snd_kcontrol_new *knew,
+				      struct usb_mixer_elem_list **listp)
+{
+	struct usb_mixer_elem_list *list;
+	struct snd_kcontrol *kctl;
+
+	list = kzalloc_obj(*list);
+	if (!list)
+		return -ENOMEM;
+	if (listp)
+		*listp = list;
+	list->mixer = mixer;
+	list->id = id;
+	list->resume = resume;
+	kctl = snd_ctl_new1(knew, list);
+	if (!kctl) {
+		kfree(list);
+		return -ENOMEM;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+	/* don't use snd_usb_mixer_add_control() here, this is a special list element */
+	return snd_usb_mixer_add_list(list, kctl, false);
+}
+
+/*
+ * Sound Blaster remote control configuration
+ *
+ * format of remote control data:
+ * Extigy:       xx 00
+ * Audigy 2 NX:  06 80 xx 00 00 00
+ * Live! 24-bit: 06 80 xx yy 22 83
+ */
+static const struct rc_config {
+	u32 usb_id;
+	u8  offset;
+	u8  length;
+	u8  packet_length;
+	u8  min_packet_length; /* minimum accepted length of the URB result */
+	u8  mute_mixer_id;
+	u32 mute_code;
+} rc_configs[] = {
+	{ USB_ID(0x041e, 0x3000), 0, 1, 2, 1,  18, 0x0013 }, /* Extigy       */
+	{ USB_ID(0x041e, 0x3020), 2, 1, 6, 6,  18, 0x0013 }, /* Audigy 2 NX  */
+	{ USB_ID(0x041e, 0x3040), 2, 2, 6, 6,  2,  0x6e91 }, /* Live! 24-bit */
+	{ USB_ID(0x041e, 0x3042), 0, 1, 1, 1,  1,  0x000d }, /* Usb X-Fi S51 */
+	{ USB_ID(0x041e, 0x30df), 0, 1, 1, 1,  1,  0x000d }, /* Usb X-Fi S51 Pro */
+	{ USB_ID(0x041e, 0x3237), 0, 1, 1, 1,  1,  0x000d }, /* Usb X-Fi S51 Pro */
+	{ USB_ID(0x041e, 0x3263), 0, 1, 1, 1,  1,  0x000d }, /* Usb X-Fi S51 Pro */
+	{ USB_ID(0x041e, 0x3048), 2, 2, 6, 6,  2,  0x6e91 }, /* Toshiba SB0500 */
+};
+
+static void snd_usb_soundblaster_remote_complete(struct urb *urb)
+{
+	struct usb_mixer_interface *mixer = urb->context;
+	const struct rc_config *rc = mixer->rc_cfg;
+	u32 code;
+
+	if (urb->status < 0 || urb->actual_length < rc->min_packet_length)
+		return;
+
+	code = mixer->rc_buffer[rc->offset];
+	if (rc->length == 2)
+		code |= mixer->rc_buffer[rc->offset + 1] << 8;
+
+	/* the Mute button actually changes the mixer control */
+	if (code == rc->mute_code)
+		snd_usb_mixer_notify_id(mixer, rc->mute_mixer_id);
+	mixer->rc_code = code;
+	wake_up(&mixer->rc_waitq);
+}
+
+static long snd_usb_sbrc_hwdep_read(struct snd_hwdep *hw, char __user *buf,
+				    long count, loff_t *offset)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	int err;
+	u32 rc_code;
+
+	if (count != 1 && count != 4)
+		return -EINVAL;
+	err = wait_event_interruptible(mixer->rc_waitq,
+				       (rc_code = xchg(&mixer->rc_code, 0)) != 0);
+	if (err == 0) {
+		if (count == 1)
+			err = put_user(rc_code, buf);
+		else
+			err = put_user(rc_code, (u32 __user *)buf);
+	}
+	return err < 0 ? err : count;
+}
+
+static __poll_t snd_usb_sbrc_hwdep_poll(struct snd_hwdep *hw, struct file *file,
+					poll_table *wait)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+
+	poll_wait(file, &mixer->rc_waitq, wait);
+	return mixer->rc_code ? EPOLLIN | EPOLLRDNORM : 0;
+}
+
+static int snd_usb_soundblaster_remote_init(struct usb_mixer_interface *mixer)
+{
+	struct snd_hwdep *hwdep;
+	int err, len, i;
+
+	for (i = 0; i < ARRAY_SIZE(rc_configs); ++i)
+		if (rc_configs[i].usb_id == mixer->chip->usb_id)
+			break;
+	if (i >= ARRAY_SIZE(rc_configs))
+		return 0;
+	mixer->rc_cfg = &rc_configs[i];
+
+	len = mixer->rc_cfg->packet_length;
+
+	init_waitqueue_head(&mixer->rc_waitq);
+	err = snd_hwdep_new(mixer->chip->card, "SB remote control", 0, &hwdep);
+	if (err < 0)
+		return err;
+	snprintf(hwdep->name, sizeof(hwdep->name),
+		 "%s remote control", mixer->chip->card->shortname);
+	hwdep->iface = SNDRV_HWDEP_IFACE_SB_RC;
+	hwdep->private_data = mixer;
+	hwdep->ops.read = snd_usb_sbrc_hwdep_read;
+	hwdep->ops.poll = snd_usb_sbrc_hwdep_poll;
+	hwdep->exclusive = 1;
+
+	mixer->rc_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!mixer->rc_urb)
+		return -ENOMEM;
+	mixer->rc_setup_packet = kmalloc_obj(*mixer->rc_setup_packet);
+	if (!mixer->rc_setup_packet) {
+		usb_free_urb(mixer->rc_urb);
+		mixer->rc_urb = NULL;
+		return -ENOMEM;
+	}
+	mixer->rc_setup_packet->bRequestType =
+		USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE;
+	mixer->rc_setup_packet->bRequest = UAC_GET_MEM;
+	mixer->rc_setup_packet->wValue = cpu_to_le16(0);
+	mixer->rc_setup_packet->wIndex = cpu_to_le16(0);
+	mixer->rc_setup_packet->wLength = cpu_to_le16(len);
+	usb_fill_control_urb(mixer->rc_urb, mixer->chip->dev,
+			     usb_rcvctrlpipe(mixer->chip->dev, 0),
+			     (u8 *)mixer->rc_setup_packet, mixer->rc_buffer, len,
+			     snd_usb_soundblaster_remote_complete, mixer);
+	return 0;
+}
+
+#define snd_audigy2nx_led_info		snd_ctl_boolean_mono_info
+
+static int snd_audigy2nx_led_get(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = kcontrol->private_value >> 8;
+	return 0;
+}
+
+static int snd_audigy2nx_led_update(struct usb_mixer_interface *mixer,
+				    int value, int index)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	if (chip->usb_id == USB_ID(0x041e, 0x3042) ||	/* USB X-Fi S51 */
+	    chip->usb_id == USB_ID(0x041e, 0x30df))	/* USB X-Fi S51 Pro */
+		err = snd_usb_ctl_msg(chip->dev,
+				      usb_sndctrlpipe(chip->dev, 0), 0x24,
+				      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+				      !value, 0, NULL, 0);
+	else
+		err = snd_usb_ctl_msg(chip->dev,
+				      usb_sndctrlpipe(chip->dev, 0), 0x24,
+				      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+				      value, index + 2, NULL, 0);
+	return err;
+}
+
+static int snd_audigy2nx_led_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+	int index = kcontrol->private_value & 0xff;
+	unsigned int value = ucontrol->value.integer.value[0];
+	int old_value = kcontrol->private_value >> 8;
+	unsigned long old_pval = kcontrol->private_value;
+	int err;
+
+	if (value > 1)
+		return -EINVAL;
+	if (value == old_value)
+		return 0;
+	kcontrol->private_value = (value << 8) | index;
+	err = snd_audigy2nx_led_update(mixer, value, index);
+	if (err < 0) {
+		kcontrol->private_value = old_pval;
+		return err;
+	}
+	return 1;
+}
+
+static int snd_audigy2nx_led_resume(struct usb_mixer_elem_list *list)
+{
+	int priv_value = list->kctl->private_value;
+
+	return snd_audigy2nx_led_update(list->mixer, priv_value >> 8,
+					priv_value & 0xff);
+}
+
+/* name and private_value are set dynamically */
+static const struct snd_kcontrol_new snd_audigy2nx_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.info = snd_audigy2nx_led_info,
+	.get = snd_audigy2nx_led_get,
+	.put = snd_audigy2nx_led_put,
+};
+
+static const char * const snd_audigy2nx_led_names[] = {
+	"CMSS LED Switch",
+	"Power LED Switch",
+	"Dolby Digital LED Switch",
+};
+
+static int snd_audigy2nx_controls_create(struct usb_mixer_interface *mixer)
+{
+	int i, err;
+
+	for (i = 0; i < ARRAY_SIZE(snd_audigy2nx_led_names); ++i) {
+		struct snd_kcontrol_new knew;
+
+		/* USB X-Fi S51 doesn't have a CMSS LED */
+		if (mixer->chip->usb_id == USB_ID(0x041e, 0x3042) && i == 0)
+			continue;
+		/* USB X-Fi S51 Pro doesn't have one either */
+		if (mixer->chip->usb_id == USB_ID(0x041e, 0x30df) && i == 0)
+			continue;
+		if (i > 1 && /* Live24ext has 2 LEDs only */
+			(mixer->chip->usb_id == USB_ID(0x041e, 0x3040) ||
+			 mixer->chip->usb_id == USB_ID(0x041e, 0x3042) ||
+			 mixer->chip->usb_id == USB_ID(0x041e, 0x30df) ||
+			 mixer->chip->usb_id == USB_ID(0x041e, 0x3048)))
+			break;
+
+		knew = snd_audigy2nx_control;
+		knew.name = snd_audigy2nx_led_names[i];
+		knew.private_value = (1 << 8) | i; /* LED on as default */
+		err = add_single_ctl_with_resume(mixer, 0,
+						 snd_audigy2nx_led_resume,
+						 &knew, NULL);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static void snd_audigy2nx_proc_read(struct snd_info_entry *entry,
+				    struct snd_info_buffer *buffer)
+{
+	static const struct sb_jack {
+		int unitid;
+		const char *name;
+	}  jacks_audigy2nx[] = {
+		{4,  "dig in "},
+		{7,  "line in"},
+		{19, "spk out"},
+		{20, "hph out"},
+		{-1, NULL}
+	}, jacks_live24ext[] = {
+		{4,  "line in"}, /* &1=Line, &2=Mic*/
+		{3,  "hph out"}, /* headphones */
+		{0,  "RC     "}, /* last command, 6 bytes see rc_config above */
+		{-1, NULL}
+	};
+	const struct sb_jack *jacks;
+	struct usb_mixer_interface *mixer = entry->private_data;
+	int i, err;
+	u8 buf[3];
+
+	snd_iprintf(buffer, "%s jacks\n\n", mixer->chip->card->shortname);
+	if (mixer->chip->usb_id == USB_ID(0x041e, 0x3020))
+		jacks = jacks_audigy2nx;
+	else if (mixer->chip->usb_id == USB_ID(0x041e, 0x3040) ||
+		 mixer->chip->usb_id == USB_ID(0x041e, 0x3048))
+		jacks = jacks_live24ext;
+	else
+		return;
+
+	for (i = 0; jacks[i].name; ++i) {
+		snd_iprintf(buffer, "%s: ", jacks[i].name);
+		CLASS(snd_usb_lock, pm)(mixer->chip);
+		if (pm.err < 0)
+			return;
+		err = snd_usb_ctl_msg(mixer->chip->dev,
+				      usb_rcvctrlpipe(mixer->chip->dev, 0),
+				      UAC_GET_MEM, USB_DIR_IN | USB_TYPE_CLASS |
+				      USB_RECIP_INTERFACE, 0,
+				      jacks[i].unitid << 8, buf, 3);
+		if (err == 3 && (buf[0] == 3 || buf[0] == 6))
+			snd_iprintf(buffer, "%02x %02x\n", buf[1], buf[2]);
+		else
+			snd_iprintf(buffer, "?\n");
+	}
+}
+
+/* EMU0204 */
+static int snd_emu0204_ch_switch_info(struct snd_kcontrol *kcontrol,
+				      struct snd_ctl_elem_info *uinfo)
+{
+	static const char * const texts[2] = {"1/2", "3/4"};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_emu0204_ch_switch_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.enumerated.item[0] = kcontrol->private_value;
+	return 0;
+}
+
+static int snd_emu0204_ch_switch_update(struct usb_mixer_interface *mixer,
+					int value)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	unsigned char buf[2];
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	buf[0] = 0x01;
+	buf[1] = value ? 0x02 : 0x01;
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0), UAC_SET_CUR,
+			       USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			       0x0400, 0x0e00, buf, 2);
+}
+
+static int snd_emu0204_ch_switch_put(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+	unsigned int value = ucontrol->value.enumerated.item[0];
+	unsigned long old_pval = kcontrol->private_value;
+	int err;
+
+	if (value > 1)
+		return -EINVAL;
+
+	if (value == kcontrol->private_value)
+		return 0;
+
+	kcontrol->private_value = value;
+	err = snd_emu0204_ch_switch_update(mixer, value);
+	if (err < 0) {
+		kcontrol->private_value = old_pval;
+		return err;
+	}
+	return 1;
+}
+
+static int snd_emu0204_ch_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_emu0204_ch_switch_update(list->mixer,
+					    list->kctl->private_value);
+}
+
+static const struct snd_kcontrol_new snd_emu0204_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Front Jack Channels",
+	.info = snd_emu0204_ch_switch_info,
+	.get = snd_emu0204_ch_switch_get,
+	.put = snd_emu0204_ch_switch_put,
+	.private_value = 0,
+};
+
+static int snd_emu0204_controls_create(struct usb_mixer_interface *mixer)
+{
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_emu0204_ch_switch_resume,
+					  &snd_emu0204_control, NULL);
+}
+
+#if IS_REACHABLE(CONFIG_INPUT)
+/*
+ * Sony DualSense controller (PS5) jack detection
+ *
+ * Since this is an UAC 1 device, it doesn't support jack detection.
+ * However, the controller hid-playstation driver reports HP & MIC
+ * insert events through a dedicated input device.
+ */
+
+#define SND_DUALSENSE_JACK_OUT_TERM_ID 3
+#define SND_DUALSENSE_JACK_IN_TERM_ID 4
+
+struct dualsense_mixer_elem_info {
+	struct usb_mixer_elem_info info;
+	struct input_handler ih;
+	struct input_device_id id_table[2];
+	bool connected;
+};
+
+static void snd_dualsense_ih_event(struct input_handle *handle,
+				   unsigned int type, unsigned int code,
+				   int value)
+{
+	struct dualsense_mixer_elem_info *mei;
+	struct usb_mixer_elem_list *me;
+
+	if (type != EV_SW)
+		return;
+
+	mei = container_of(handle->handler, struct dualsense_mixer_elem_info, ih);
+	me = &mei->info.head;
+
+	if ((me->id == SND_DUALSENSE_JACK_OUT_TERM_ID && code == SW_HEADPHONE_INSERT) ||
+	    (me->id == SND_DUALSENSE_JACK_IN_TERM_ID && code == SW_MICROPHONE_INSERT)) {
+		mei->connected = !!value;
+		snd_ctl_notify(me->mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &me->kctl->id);
+	}
+}
+
+static bool snd_dualsense_ih_match(struct input_handler *handler,
+				   struct input_dev *dev)
+{
+	struct dualsense_mixer_elem_info *mei;
+	struct usb_device *snd_dev;
+	struct device *parent;
+
+	mei = container_of(handler, struct dualsense_mixer_elem_info, ih);
+	snd_dev = mei->info.head.mixer->chip->dev;
+
+	/*
+	 * Ensure the VID:PID matched input device supposedly owned by the
+	 * hid-playstation driver belongs to the actual hardware handled by
+	 * the current USB audio device.
+	 *
+	 * This verification is necessary when there is more than one identical
+	 * controller attached to the host system.
+	 *
+	 * The input device is registered below the HID device, USB interface and
+	 * USB device, so compare the parent chain directly instead of building
+	 * kobject path strings. This avoids dereferencing kobject names while the
+	 * USB device hierarchy is being torn down during disconnect.
+	 */
+	for (parent = dev->dev.parent; parent; parent = parent->parent) {
+		if (parent == &snd_dev->dev)
+			return true;
+	}
+
+	return false;
+}
+
+static int snd_dualsense_ih_connect(struct input_handler *handler,
+				    struct input_dev *dev,
+				    const struct input_device_id *id)
+{
+	struct input_handle *handle;
+	int err;
+
+	handle = kzalloc_obj(*handle);
+	if (!handle)
+		return -ENOMEM;
+
+	handle->dev = dev;
+	handle->handler = handler;
+	handle->name = handler->name;
+
+	err = input_register_handle(handle);
+	if (err)
+		goto err_free;
+
+	err = input_open_device(handle);
+	if (err)
+		goto err_unregister;
+
+	return 0;
+
+err_unregister:
+	input_unregister_handle(handle);
+err_free:
+	kfree(handle);
+	return err;
+}
+
+static void snd_dualsense_ih_disconnect(struct input_handle *handle)
+{
+	input_close_device(handle);
+	input_unregister_handle(handle);
+	kfree(handle);
+}
+
+static void snd_dualsense_ih_start(struct input_handle *handle)
+{
+	struct dualsense_mixer_elem_info *mei;
+	struct usb_mixer_elem_list *me;
+	int status = -1;
+
+	mei = container_of(handle->handler, struct dualsense_mixer_elem_info, ih);
+	me = &mei->info.head;
+
+	if (me->id == SND_DUALSENSE_JACK_OUT_TERM_ID &&
+	    test_bit(SW_HEADPHONE_INSERT, handle->dev->swbit))
+		status = test_bit(SW_HEADPHONE_INSERT, handle->dev->sw);
+	else if (me->id == SND_DUALSENSE_JACK_IN_TERM_ID &&
+		 test_bit(SW_MICROPHONE_INSERT, handle->dev->swbit))
+		status = test_bit(SW_MICROPHONE_INSERT, handle->dev->sw);
+
+	if (status >= 0) {
+		mei->connected = !!status;
+		snd_ctl_notify(me->mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &me->kctl->id);
+	}
+}
+
+static int snd_dualsense_jack_get(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct dualsense_mixer_elem_info *mei = snd_kcontrol_chip(kctl);
+
+	ucontrol->value.integer.value[0] = mei->connected;
+
+	return 0;
+}
+
+static const struct snd_kcontrol_new snd_dualsense_jack_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.info = snd_ctl_boolean_mono_info,
+	.get = snd_dualsense_jack_get,
+};
+
+static int snd_dualsense_resume_jack(struct usb_mixer_elem_list *list)
+{
+	snd_ctl_notify(list->mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &list->kctl->id);
+	return 0;
+}
+
+static void snd_dualsense_mixer_elem_free(struct snd_kcontrol *kctl)
+{
+	struct dualsense_mixer_elem_info *mei = snd_kcontrol_chip(kctl);
+
+	if (mei->ih.event)
+		input_unregister_handler(&mei->ih);
+
+	snd_usb_mixer_elem_free(kctl);
+}
+
+static int snd_dualsense_jack_create(struct usb_mixer_interface *mixer,
+				     const char *name, bool is_output)
+{
+	struct dualsense_mixer_elem_info *mei;
+	struct input_device_id *idev_id;
+	struct snd_kcontrol *kctl;
+	int err;
+
+	mei = kzalloc_obj(*mei);
+	if (!mei)
+		return -ENOMEM;
+
+	snd_usb_mixer_elem_init_std(&mei->info.head, mixer,
+				    is_output ? SND_DUALSENSE_JACK_OUT_TERM_ID :
+						SND_DUALSENSE_JACK_IN_TERM_ID);
+
+	mei->info.head.resume = snd_dualsense_resume_jack;
+	mei->info.val_type = USB_MIXER_BOOLEAN;
+	mei->info.channels = 1;
+	mei->info.min = 0;
+	mei->info.max = 1;
+
+	kctl = snd_ctl_new1(&snd_dualsense_jack_control, mei);
+	if (!kctl) {
+		kfree(mei);
+		return -ENOMEM;
+	}
+
+	strscpy(kctl->id.name, name, sizeof(kctl->id.name));
+	kctl->private_free = snd_dualsense_mixer_elem_free;
+
+	err = snd_usb_mixer_add_control(&mei->info.head, kctl);
+	if (err)
+		return err;
+
+	idev_id = &mei->id_table[0];
+	idev_id->flags = INPUT_DEVICE_ID_MATCH_VENDOR | INPUT_DEVICE_ID_MATCH_PRODUCT |
+			 INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_SWBIT;
+	idev_id->vendor = USB_ID_VENDOR(mixer->chip->usb_id);
+	idev_id->product = USB_ID_PRODUCT(mixer->chip->usb_id);
+	idev_id->evbit[BIT_WORD(EV_SW)] = BIT_MASK(EV_SW);
+	if (is_output)
+		idev_id->swbit[BIT_WORD(SW_HEADPHONE_INSERT)] = BIT_MASK(SW_HEADPHONE_INSERT);
+	else
+		idev_id->swbit[BIT_WORD(SW_MICROPHONE_INSERT)] = BIT_MASK(SW_MICROPHONE_INSERT);
+
+	mei->ih.event = snd_dualsense_ih_event;
+	mei->ih.match = snd_dualsense_ih_match;
+	mei->ih.connect = snd_dualsense_ih_connect;
+	mei->ih.disconnect = snd_dualsense_ih_disconnect;
+	mei->ih.start = snd_dualsense_ih_start;
+	mei->ih.name = name;
+	mei->ih.id_table = mei->id_table;
+
+	err = input_register_handler(&mei->ih);
+	if (err) {
+		dev_warn(&mixer->chip->dev->dev,
+			 "Could not register input handler: %d\n", err);
+		mei->ih.event = NULL;
+	}
+
+	return 0;
+}
+
+static int snd_dualsense_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = snd_dualsense_jack_create(mixer, "Headphone Jack", true);
+	if (err < 0)
+		return err;
+
+	return snd_dualsense_jack_create(mixer, "Headset Mic Jack", false);
+}
+#endif /* IS_REACHABLE(CONFIG_INPUT) */
+
+/* ASUS Xonar U1 / U3 controls */
+
+static int snd_xonar_u1_switch_get(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = !!(kcontrol->private_value & 0x02);
+	return 0;
+}
+
+static int snd_xonar_u1_switch_update(struct usb_mixer_interface *mixer,
+				      unsigned char status)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0), 0x08,
+			       USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			       50, 0, &status, 1);
+}
+
+static int snd_xonar_u1_switch_put(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	u8 old_status, new_status;
+	int err;
+
+	old_status = kcontrol->private_value;
+	if (ucontrol->value.integer.value[0])
+		new_status = old_status | 0x02;
+	else
+		new_status = old_status & ~0x02;
+	if (new_status == old_status)
+		return 0;
+
+	kcontrol->private_value = new_status;
+	err = snd_xonar_u1_switch_update(list->mixer, new_status);
+	if (err < 0) {
+		kcontrol->private_value = old_status;
+		return err;
+	}
+	return 1;
+}
+
+static int snd_xonar_u1_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_xonar_u1_switch_update(list->mixer,
+					  list->kctl->private_value);
+}
+
+static const struct snd_kcontrol_new snd_xonar_u1_output_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Digital Playback Switch",
+	.info = snd_ctl_boolean_mono_info,
+	.get = snd_xonar_u1_switch_get,
+	.put = snd_xonar_u1_switch_put,
+	.private_value = 0x05,
+};
+
+static int snd_xonar_u1_controls_create(struct usb_mixer_interface *mixer)
+{
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_xonar_u1_switch_resume,
+					  &snd_xonar_u1_output_switch, NULL);
+}
+
+/* Digidesign Mbox 1 helper functions */
+
+static int snd_mbox1_is_spdif_synced(struct snd_usb_audio *chip)
+{
+	unsigned char buff[3];
+	int err;
+	int is_spdif_synced;
+
+	/* Read clock source */
+	err = snd_usb_ctl_msg(chip->dev,
+			      usb_rcvctrlpipe(chip->dev, 0), 0x81,
+			      USB_DIR_IN |
+			      USB_TYPE_CLASS |
+			      USB_RECIP_ENDPOINT, 0x100, 0x81, buff, 3);
+	if (err < 0)
+		return err;
+
+	/* spdif sync: buff is all zeroes */
+	is_spdif_synced = !(buff[0] | buff[1] | buff[2]);
+	return is_spdif_synced;
+}
+
+static int snd_mbox1_set_clk_source(struct snd_usb_audio *chip, int rate_or_zero)
+{
+	/* 2 possibilities:	Internal    -> expects sample rate
+	 *			S/PDIF sync -> expects rate = 0
+	 */
+	unsigned char buff[3];
+
+	buff[0] = (rate_or_zero >>  0) & 0xff;
+	buff[1] = (rate_or_zero >>  8) & 0xff;
+	buff[2] = (rate_or_zero >> 16) & 0xff;
+
+	/* Set clock source */
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0), 0x1,
+			       USB_TYPE_CLASS |
+			       USB_RECIP_ENDPOINT, 0x100, 0x81, buff, 3);
+}
+
+static int snd_mbox1_is_spdif_input(struct snd_usb_audio *chip)
+{
+	/* Hardware gives 2 possibilities:	ANALOG Source  -> 0x01
+	 *					S/PDIF Source  -> 0x02
+	 */
+	int err;
+	unsigned char source[1];
+
+	/* Read input source */
+	err = snd_usb_ctl_msg(chip->dev,
+			      usb_rcvctrlpipe(chip->dev, 0), 0x81,
+			      USB_DIR_IN |
+			      USB_TYPE_CLASS |
+			      USB_RECIP_INTERFACE, 0x00, 0x500, source, 1);
+	if (err < 0)
+		return err;
+
+	return (source[0] == 2);
+}
+
+static int snd_mbox1_set_input_source(struct snd_usb_audio *chip, int is_spdif)
+{
+	/* NB: Setting the input source to S/PDIF resets the clock source to S/PDIF
+	 * Hardware expects 2 possibilities:	ANALOG Source  -> 0x01
+	 *					S/PDIF Source  -> 0x02
+	 */
+	unsigned char buff[1];
+
+	buff[0] = (is_spdif & 1) + 1;
+
+	/* Set input source */
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0), 0x1,
+			       USB_TYPE_CLASS |
+			       USB_RECIP_INTERFACE, 0x00, 0x500, buff, 1);
+}
+
+/* Digidesign Mbox 1 clock source switch (internal/spdif) */
+
+static int snd_mbox1_clk_switch_get(struct snd_kcontrol *kctl,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct snd_usb_audio *chip = list->mixer->chip;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	err = snd_mbox1_is_spdif_synced(chip);
+	if (err < 0)
+		return err;
+
+	kctl->private_value = err;
+	ucontrol->value.enumerated.item[0] = kctl->private_value;
+	return 0;
+}
+
+static int snd_mbox1_clk_switch_update(struct usb_mixer_interface *mixer, int is_spdif_sync)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	err = snd_mbox1_is_spdif_input(chip);
+	if (err < 0)
+		return err;
+
+	err = snd_mbox1_is_spdif_synced(chip);
+	if (err < 0)
+		return err;
+
+	/* FIXME: hardcoded sample rate */
+	err = snd_mbox1_set_clk_source(chip, is_spdif_sync ? 0 : 48000);
+	if (err < 0)
+		return err;
+
+	return snd_mbox1_is_spdif_synced(chip);
+}
+
+static int snd_mbox1_clk_switch_put(struct snd_kcontrol *kctl,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+	int err;
+	bool cur_val, new_val;
+
+	cur_val = kctl->private_value;
+	new_val = ucontrol->value.enumerated.item[0];
+	if (cur_val == new_val)
+		return 0;
+
+	kctl->private_value = new_val;
+	err = snd_mbox1_clk_switch_update(mixer, new_val);
+	return err < 0 ? err : 1;
+}
+
+static int snd_mbox1_clk_switch_info(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[2] = {
+		"Internal",
+		"S/PDIF"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_mbox1_clk_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_mbox1_clk_switch_update(list->mixer, list->kctl->private_value);
+}
+
+/* Digidesign Mbox 1 input source switch (analog/spdif) */
+
+static int snd_mbox1_src_switch_get(struct snd_kcontrol *kctl,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.enumerated.item[0] = kctl->private_value;
+	return 0;
+}
+
+static int snd_mbox1_src_switch_update(struct usb_mixer_interface *mixer, int is_spdif_input)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	err = snd_mbox1_is_spdif_input(chip);
+	if (err < 0)
+		return err;
+
+	err = snd_mbox1_set_input_source(chip, is_spdif_input);
+	if (err < 0)
+		return err;
+
+	err = snd_mbox1_is_spdif_input(chip);
+	if (err < 0)
+		return err;
+
+	return snd_mbox1_is_spdif_synced(chip);
+}
+
+static int snd_mbox1_src_switch_put(struct snd_kcontrol *kctl,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+	int err;
+	bool cur_val, new_val;
+
+	cur_val = kctl->private_value;
+	new_val = ucontrol->value.enumerated.item[0];
+	if (cur_val == new_val)
+		return 0;
+
+	kctl->private_value = new_val;
+	err = snd_mbox1_src_switch_update(mixer, new_val);
+	return err < 0 ? err : 1;
+}
+
+static int snd_mbox1_src_switch_info(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[2] = {
+		"Analog",
+		"S/PDIF"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_mbox1_src_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_mbox1_src_switch_update(list->mixer, list->kctl->private_value);
+}
+
+static const struct snd_kcontrol_new snd_mbox1_clk_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Clock Source",
+	.index = 0,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.info = snd_mbox1_clk_switch_info,
+	.get = snd_mbox1_clk_switch_get,
+	.put = snd_mbox1_clk_switch_put,
+	.private_value = 0
+};
+
+static const struct snd_kcontrol_new snd_mbox1_src_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Input Source",
+	.index = 1,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.info = snd_mbox1_src_switch_info,
+	.get = snd_mbox1_src_switch_get,
+	.put = snd_mbox1_src_switch_put,
+	.private_value = 0
+};
+
+static int snd_mbox1_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = add_single_ctl_with_resume(mixer, 0,
+					 snd_mbox1_clk_switch_resume,
+					 &snd_mbox1_clk_switch, NULL);
+	if (err < 0)
+		return err;
+
+	return add_single_ctl_with_resume(mixer, 1,
+					  snd_mbox1_src_switch_resume,
+					  &snd_mbox1_src_switch, NULL);
+}
+
+/* Native Instruments device quirks */
+
+#define _MAKE_NI_CONTROL(bRequest, wIndex) ((bRequest) << 16 | (wIndex))
+
+static int snd_ni_control_init_val(struct usb_mixer_interface *mixer,
+				   struct snd_kcontrol *kctl)
+{
+	struct usb_device *dev = mixer->chip->dev;
+	unsigned int pval = kctl->private_value;
+	u8 value;
+	int err;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      (pval >> 16) & 0xff,
+			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+			      0, pval & 0xffff, &value, 1);
+	if (err < 0) {
+		dev_err(&dev->dev,
+			"unable to issue vendor read request (ret = %d)", err);
+		return err;
+	}
+
+	kctl->private_value |= ((unsigned int)value << 24);
+	return 0;
+}
+
+static int snd_nativeinstruments_control_get(struct snd_kcontrol *kcontrol,
+					     struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = kcontrol->private_value >> 24;
+	return 0;
+}
+
+static int snd_ni_update_cur_val(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+	return usb_control_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
+			       (pval >> 16) & 0xff,
+			       USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+			       pval >> 24, pval & 0xffff, NULL, 0, 1000);
+}
+
+static int snd_nativeinstruments_control_put(struct snd_kcontrol *kcontrol,
+					     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	unsigned long old_pval = kcontrol->private_value;
+	u8 oldval = (old_pval >> 24) & 0xff;
+	u8 newval = ucontrol->value.integer.value[0];
+	int err;
+
+	if (oldval == newval)
+		return 0;
+
+	kcontrol->private_value &= ~(0xff << 24);
+	kcontrol->private_value |= (unsigned int)newval << 24;
+	err = snd_ni_update_cur_val(list);
+	if (err < 0) {
+		kcontrol->private_value = old_pval;
+		return err;
+	}
+	return 1;
+}
+
+static const struct snd_kcontrol_new snd_nativeinstruments_ta6_mixers[] = {
+	{
+		.name = "Direct Thru Channel A",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x03),
+	},
+	{
+		.name = "Direct Thru Channel B",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x05),
+	},
+	{
+		.name = "Phono Input Channel A",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x03),
+	},
+	{
+		.name = "Phono Input Channel B",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x05),
+	},
+};
+
+static const struct snd_kcontrol_new snd_nativeinstruments_ta10_mixers[] = {
+	{
+		.name = "Direct Thru Channel A",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x03),
+	},
+	{
+		.name = "Direct Thru Channel B",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x05),
+	},
+	{
+		.name = "Direct Thru Channel C",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x07),
+	},
+	{
+		.name = "Direct Thru Channel D",
+		.private_value = _MAKE_NI_CONTROL(0x01, 0x09),
+	},
+	{
+		.name = "Phono Input Channel A",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x03),
+	},
+	{
+		.name = "Phono Input Channel B",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x05),
+	},
+	{
+		.name = "Phono Input Channel C",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x07),
+	},
+	{
+		.name = "Phono Input Channel D",
+		.private_value = _MAKE_NI_CONTROL(0x02, 0x09),
+	},
+};
+
+static int snd_nativeinstruments_create_mixer(struct usb_mixer_interface *mixer,
+					      const struct snd_kcontrol_new *kc,
+					      unsigned int count)
+{
+	int i, err = 0;
+	struct snd_kcontrol_new template = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.get = snd_nativeinstruments_control_get,
+		.put = snd_nativeinstruments_control_put,
+		.info = snd_ctl_boolean_mono_info,
+	};
+
+	for (i = 0; i < count; i++) {
+		struct usb_mixer_elem_list *list;
+
+		template.name = kc[i].name;
+		template.private_value = kc[i].private_value;
+
+		err = add_single_ctl_with_resume(mixer, 0,
+						 snd_ni_update_cur_val,
+						 &template, &list);
+		if (err < 0)
+			break;
+		snd_ni_control_init_val(mixer, list->kctl);
+	}
+
+	return err;
+}
+
+/* M-Audio FastTrack Ultra quirks */
+/* FTU Effect switch (also used by C400/C600) */
+static int snd_ftu_eff_switch_info(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[8] = {
+		"Room 1", "Room 2", "Room 3", "Hall 1",
+		"Hall 2", "Plate", "Delay", "Echo"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_ftu_eff_switch_init(struct usb_mixer_interface *mixer,
+				   struct snd_kcontrol *kctl)
+{
+	struct usb_device *dev = mixer->chip->dev;
+	unsigned int pval = kctl->private_value;
+	int err;
+	unsigned char value[2];
+
+	value[0] = 0x00;
+	value[1] = 0x00;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			      (pval & 0xff00) | ((pval & 0xff0000) >> 16),
+			      snd_usb_ctrl_intf(mixer->hostif) | ((pval & 0xff) << 8),
+			      value, 2);
+	if (err < 0)
+		return err;
+
+	kctl->private_value |= (unsigned int)value[0] << 24;
+	return 0;
+}
+
+static int snd_ftu_eff_switch_get(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.enumerated.item[0] = kctl->private_value >> 24;
+	return 0;
+}
+
+static int snd_ftu_eff_switch_update(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
+	unsigned char value[2];
+
+	value[0] = pval >> 24;
+	value[1] = 0;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0),
+			       UAC_SET_CUR,
+			       USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			       (pval & 0xff00) | ((pval & 0xff0000) >> 16),
+			       snd_usb_ctrl_intf(list->mixer->hostif) | ((pval & 0xff) << 8),
+			       value, 2);
+}
+
+static int snd_ftu_eff_switch_put(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	unsigned long old_pval = list->kctl->private_value;
+	unsigned int pval = old_pval;
+	int cur_val, err, new_val;
+
+	cur_val = pval >> 24;
+	new_val = ucontrol->value.enumerated.item[0];
+	if (cur_val == new_val)
+		return 0;
+
+	kctl->private_value &= ~(0xff << 24);
+	kctl->private_value |= new_val << 24;
+	err = snd_ftu_eff_switch_update(list);
+	if (err < 0) {
+		kctl->private_value = old_pval;
+		return err;
+	}
+	return 1;
+}
+
+static int snd_ftu_create_effect_switch(struct usb_mixer_interface *mixer,
+					int validx, int bUnitID)
+{
+	static struct snd_kcontrol_new template = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Effect Program Switch",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_ftu_eff_switch_info,
+		.get = snd_ftu_eff_switch_get,
+		.put = snd_ftu_eff_switch_put
+	};
+	struct usb_mixer_elem_list *list;
+	int err;
+
+	err = add_single_ctl_with_resume(mixer, bUnitID,
+					 snd_ftu_eff_switch_update,
+					 &template, &list);
+	if (err < 0)
+		return err;
+	list->kctl->private_value = (validx << 8) | bUnitID;
+	snd_ftu_eff_switch_init(mixer, list->kctl);
+	return 0;
+}
+
+/* Create volume controls for FTU devices*/
+static int snd_ftu_create_volume_ctls(struct usb_mixer_interface *mixer)
+{
+	char name[64];
+	unsigned int control, cmask;
+	int in, out, err;
+
+	const unsigned int id = 5;
+	const int val_type = USB_MIXER_S16;
+
+	for (out = 0; out < 8; out++) {
+		control = out + 1;
+		for (in = 0; in < 8; in++) {
+			cmask = BIT(in);
+			snprintf(name, sizeof(name),
+				 "AIn%d - Out%d Capture Volume",
+				 in  + 1, out + 1);
+			err = snd_create_std_mono_ctl(mixer, id, control,
+						      cmask, val_type, name,
+						      &snd_usb_mixer_vol_tlv);
+			if (err < 0)
+				return err;
+		}
+		for (in = 8; in < 16; in++) {
+			cmask = BIT(in);
+			snprintf(name, sizeof(name),
+				 "DIn%d - Out%d Playback Volume",
+				 in - 7, out + 1);
+			err = snd_create_std_mono_ctl(mixer, id, control,
+						      cmask, val_type, name,
+						      &snd_usb_mixer_vol_tlv);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_ftu_create_effect_volume_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Volume";
+	const unsigned int id = 6;
+	const int val_type = USB_MIXER_U8;
+	const unsigned int control = 2;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, snd_usb_mixer_vol_tlv);
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_ftu_create_effect_duration_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Duration";
+	const unsigned int id = 6;
+	const int val_type = USB_MIXER_S16;
+	const unsigned int control = 3;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, snd_usb_mixer_vol_tlv);
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_ftu_create_effect_feedback_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Feedback Volume";
+	const unsigned int id = 6;
+	const int val_type = USB_MIXER_U8;
+	const unsigned int control = 4;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+					name, NULL);
+}
+
+static int snd_ftu_create_effect_return_ctls(struct usb_mixer_interface *mixer)
+{
+	unsigned int cmask;
+	int err, ch;
+	char name[48];
+
+	const unsigned int id = 7;
+	const int val_type = USB_MIXER_S16;
+	const unsigned int control = 7;
+
+	for (ch = 0; ch < 4; ++ch) {
+		cmask = BIT(ch);
+		snprintf(name, sizeof(name),
+			 "Effect Return %d Volume", ch + 1);
+		err = snd_create_std_mono_ctl(mixer, id, control,
+					      cmask, val_type, name,
+					      snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int snd_ftu_create_effect_send_ctls(struct usb_mixer_interface *mixer)
+{
+	unsigned int  cmask;
+	int err, ch;
+	char name[48];
+
+	const unsigned int id = 5;
+	const int val_type = USB_MIXER_S16;
+	const unsigned int control = 9;
+
+	for (ch = 0; ch < 8; ++ch) {
+		cmask = BIT(ch);
+		snprintf(name, sizeof(name),
+			 "Effect Send AIn%d Volume", ch + 1);
+		err = snd_create_std_mono_ctl(mixer, id, control, cmask,
+					      val_type, name,
+					      snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+	for (ch = 8; ch < 16; ++ch) {
+		cmask = BIT(ch);
+		snprintf(name, sizeof(name),
+			 "Effect Send DIn%d Volume", ch - 7);
+		err = snd_create_std_mono_ctl(mixer, id, control, cmask,
+					      val_type, name,
+					      snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static int snd_ftu_create_mixer(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = snd_ftu_create_volume_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_switch(mixer, 1, 6);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_volume_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_duration_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_feedback_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_return_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_send_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+void snd_emuusb_set_samplerate(struct snd_usb_audio *chip,
+			       unsigned char samplerate_id)
+{
+	struct usb_mixer_interface *mixer;
+	struct usb_mixer_elem_info *cval;
+	int err;
+	int unitid = 12; /* SampleRate ExtensionUnit ID */
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		if (mixer->id_elems[unitid]) {
+			cval = mixer_elem_list_to_info(mixer->id_elems[unitid]);
+			err = snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR,
+							  cval->control << 8,
+							  samplerate_id);
+			if (!err)
+				snd_usb_mixer_notify_id(mixer, unitid);
+			break;
+		}
+	}
+}
+
+/* M-Audio Fast Track C400/C600 */
+/* C400/C600 volume controls, this control needs a volume quirk, see mixer.c */
+static int snd_c400_create_vol_ctls(struct usb_mixer_interface *mixer)
+{
+	char name[64];
+	unsigned int cmask, offset;
+	int out, chan, err;
+	int num_outs = 0;
+	int num_ins = 0;
+
+	const unsigned int id = 0x40;
+	const int val_type = USB_MIXER_S16;
+	const int control = 1;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x0763, 0x2030):
+		num_outs = 6;
+		num_ins = 4;
+		break;
+	case USB_ID(0x0763, 0x2031):
+		num_outs = 8;
+		num_ins = 6;
+		break;
+	}
+
+	for (chan = 0; chan < num_outs + num_ins; chan++) {
+		for (out = 0; out < num_outs; out++) {
+			if (chan < num_outs) {
+				snprintf(name, sizeof(name),
+					 "PCM%d-Out%d Playback Volume",
+					 chan + 1, out + 1);
+			} else {
+				snprintf(name, sizeof(name),
+					 "In%d-Out%d Playback Volume",
+					 chan - num_outs + 1, out + 1);
+			}
+
+			cmask = (out == 0) ? 0 : BIT(out - 1);
+			offset = chan * num_outs;
+			err = snd_create_std_mono_ctl_offset(mixer, id, control,
+							     cmask, val_type, offset, name,
+							     &snd_usb_mixer_vol_tlv);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_c400_create_effect_volume_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Volume";
+	const unsigned int id = 0x43;
+	const int val_type = USB_MIXER_U8;
+	const unsigned int control = 3;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+				       name, snd_usb_mixer_vol_tlv);
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_c400_create_effect_duration_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Duration";
+	const unsigned int id = 0x43;
+	const int val_type = USB_MIXER_S16;
+	const unsigned int control = 4;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+				       name, snd_usb_mixer_vol_tlv);
+}
+
+/* This control needs a volume quirk, see mixer.c */
+static int snd_c400_create_effect_feedback_ctl(struct usb_mixer_interface *mixer)
+{
+	static const char name[] = "Effect Feedback Volume";
+	const unsigned int id = 0x43;
+	const int val_type = USB_MIXER_U8;
+	const unsigned int control = 5;
+	const unsigned int cmask = 0;
+
+	return snd_create_std_mono_ctl(mixer, id, control, cmask, val_type,
+				       name, NULL);
+}
+
+static int snd_c400_create_effect_vol_ctls(struct usb_mixer_interface *mixer)
+{
+	char name[64];
+	unsigned int cmask;
+	int chan, err;
+	int num_outs = 0;
+	int num_ins = 0;
+
+	const unsigned int id = 0x42;
+	const int val_type = USB_MIXER_S16;
+	const int control = 1;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x0763, 0x2030):
+		num_outs = 6;
+		num_ins = 4;
+		break;
+	case USB_ID(0x0763, 0x2031):
+		num_outs = 8;
+		num_ins = 6;
+		break;
+	}
+
+	for (chan = 0; chan < num_outs + num_ins; chan++) {
+		if (chan < num_outs) {
+			snprintf(name, sizeof(name),
+				 "Effect Send DOut%d",
+				 chan + 1);
+		} else {
+			snprintf(name, sizeof(name),
+				 "Effect Send AIn%d",
+				 chan - num_outs + 1);
+		}
+
+		cmask = (chan == 0) ? 0 : BIT(chan - 1);
+		err = snd_create_std_mono_ctl(mixer, id, control,
+					      cmask, val_type, name,
+					      &snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int snd_c400_create_effect_ret_vol_ctls(struct usb_mixer_interface *mixer)
+{
+	char name[64];
+	unsigned int cmask;
+	int chan, err;
+	int num_outs = 0;
+	int offset = 0;
+
+	const unsigned int id = 0x40;
+	const int val_type = USB_MIXER_S16;
+	const int control = 1;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x0763, 0x2030):
+		num_outs = 6;
+		offset = 0x3c;
+		/* { 0x3c, 0x43, 0x3e, 0x45, 0x40, 0x47 } */
+		break;
+	case USB_ID(0x0763, 0x2031):
+		num_outs = 8;
+		offset = 0x70;
+		/* { 0x70, 0x79, 0x72, 0x7b, 0x74, 0x7d, 0x76, 0x7f } */
+		break;
+	}
+
+	for (chan = 0; chan < num_outs; chan++) {
+		snprintf(name, sizeof(name),
+			 "Effect Return %d",
+			 chan + 1);
+
+		cmask = (chan == 0) ? 0 :
+			BIT(chan + (chan % 2) * num_outs - 1);
+		err = snd_create_std_mono_ctl_offset(mixer, id, control,
+						     cmask, val_type, offset, name,
+						     &snd_usb_mixer_vol_tlv);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/* output gain knob selectively adjusts outputs as stereo pairs */
+/* reuses functions from FTU effect switch */
+static int snd_c400_knob_switch_info(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[8] = {
+		"None", "1/2", "3/4", "1/2 3/4",
+		"5/6", "1/2 5/6", "3/4 5/6", "1/2 3/4 5/6"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static int snd_c400_create_knob_switch(struct usb_mixer_interface *mixer,
+	int validx, int bUnitID)
+{
+	static struct snd_kcontrol_new template = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Output Gain Knob",
+		.index = 0,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_c400_knob_switch_info,
+		.get = snd_ftu_eff_switch_get,
+		.put = snd_ftu_eff_switch_put
+	};
+	struct usb_mixer_elem_list *list;
+	int err;
+
+	err = add_single_ctl_with_resume(mixer, bUnitID,
+					 snd_ftu_eff_switch_update,
+					 &template, &list);
+	if (err < 0)
+		return err;
+	list->kctl->private_value = (validx << 8) | bUnitID;
+	snd_ftu_eff_switch_init(mixer, list->kctl);
+	return 0;
+}
+
+static int snd_c400_create_mixer(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = snd_c400_create_vol_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_vol_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_ret_vol_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_ftu_create_effect_switch(mixer, 2, 0x43);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_volume_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_duration_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_effect_feedback_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	err = snd_c400_create_knob_switch(mixer, 0x0900, 0x20);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/*
+ * The mixer units for Ebox-44 are corrupt, and even where they
+ * are valid they presents mono controls as L and R channels of
+ * stereo. So we provide a good mixer here.
+ */
+static const struct std_mono_table ebox44_table[] = {
+	{
+		.unitid = 4,
+		.control = 1,
+		.cmask = 0x0,
+		.val_type = USB_MIXER_INV_BOOLEAN,
+		.name = "Headphone Playback Switch"
+	},
+	{
+		.unitid = 4,
+		.control = 2,
+		.cmask = 0x1,
+		.val_type = USB_MIXER_S16,
+		.name = "Headphone A Mix Playback Volume"
+	},
+	{
+		.unitid = 4,
+		.control = 2,
+		.cmask = 0x2,
+		.val_type = USB_MIXER_S16,
+		.name = "Headphone B Mix Playback Volume"
+	},
+
+	{
+		.unitid = 7,
+		.control = 1,
+		.cmask = 0x0,
+		.val_type = USB_MIXER_INV_BOOLEAN,
+		.name = "Output Playback Switch"
+	},
+	{
+		.unitid = 7,
+		.control = 2,
+		.cmask = 0x1,
+		.val_type = USB_MIXER_S16,
+		.name = "Output A Playback Volume"
+	},
+	{
+		.unitid = 7,
+		.control = 2,
+		.cmask = 0x2,
+		.val_type = USB_MIXER_S16,
+		.name = "Output B Playback Volume"
+	},
+
+	{
+		.unitid = 10,
+		.control = 1,
+		.cmask = 0x0,
+		.val_type = USB_MIXER_INV_BOOLEAN,
+		.name = "Input Capture Switch"
+	},
+	{
+		.unitid = 10,
+		.control = 2,
+		.cmask = 0x1,
+		.val_type = USB_MIXER_S16,
+		.name = "Input A Capture Volume"
+	},
+	{
+		.unitid = 10,
+		.control = 2,
+		.cmask = 0x2,
+		.val_type = USB_MIXER_S16,
+		.name = "Input B Capture Volume"
+	},
+
+	{}
+};
+
+/* Audio Advantage Micro II findings:
+ *
+ * Mapping spdif AES bits to vendor register.bit:
+ * AES0: [0 0 0 0 2.3 2.2 2.1 2.0] - default 0x00
+ * AES1: [3.3 3.2.3.1.3.0 2.7 2.6 2.5 2.4] - default: 0x01
+ * AES2: [0 0 0 0 0 0 0 0]
+ * AES3: [0 0 0 0 0 0 x 0] - 'x' bit is set basing on standard usb request
+ *                           (UAC_EP_CS_ATTR_SAMPLE_RATE) for Audio Devices
+ *
+ * power on values:
+ * r2: 0x10
+ * r3: 0x20 (b7 is zeroed just before playback (except IEC61937) and set
+ *           just after it to 0xa0, presumably it disables/mutes some analog
+ *           parts when there is no audio.)
+ * r9: 0x28
+ *
+ * Optical transmitter on/off:
+ * vendor register.bit: 9.1
+ * 0 - on (0x28 register value)
+ * 1 - off (0x2a register value)
+ *
+ */
+static int snd_microii_spdif_info(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
+	uinfo->count = 1;
+	return 0;
+}
+
+static int snd_microii_spdif_default_get(struct snd_kcontrol *kcontrol,
+					 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = list->mixer->chip;
+	int err;
+	struct usb_interface *iface;
+	struct usb_host_interface *alts;
+	unsigned int ep;
+	unsigned char data[3];
+	int rate;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	ucontrol->value.iec958.status[0] = kcontrol->private_value & 0xff;
+	ucontrol->value.iec958.status[1] = (kcontrol->private_value >> 8) & 0xff;
+	ucontrol->value.iec958.status[2] = 0x00;
+
+	/* use known values for that card: interface#1 altsetting#1 */
+	iface = usb_ifnum_to_if(chip->dev, 1);
+	if (!iface || iface->num_altsetting < 2)
+		return -EINVAL;
+	alts = &iface->altsetting[1];
+	if (get_iface_desc(alts)->bNumEndpoints < 1)
+		return -EINVAL;
+	ep = get_endpoint(alts, 0)->bEndpointAddress;
+
+	err = snd_usb_ctl_msg(chip->dev,
+			      usb_rcvctrlpipe(chip->dev, 0),
+			      UAC_GET_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
+			      UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
+			      ep,
+			      data,
+			      sizeof(data));
+	if (err < 0)
+		return err;
+
+	rate = data[0] | (data[1] << 8) | (data[2] << 16);
+	ucontrol->value.iec958.status[3] = (rate == 48000) ?
+			IEC958_AES3_CON_FS_48000 : IEC958_AES3_CON_FS_44100;
+
+	return 0;
+}
+
+static int snd_microii_spdif_default_update(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	unsigned int pval = list->kctl->private_value;
+	u8 reg;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	reg = ((pval >> 4) & 0xf0) | (pval & 0x0f);
+	err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0),
+			      UAC_SET_CUR,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			      reg,
+			      2,
+			      NULL,
+			      0);
+	if (err < 0)
+		return err;
+
+	reg = (pval & IEC958_AES0_NONAUDIO) ? 0xa0 : 0x20;
+	reg |= (pval >> 12) & 0x0f;
+	err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0),
+			      UAC_SET_CUR,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			      reg,
+			      3,
+			      NULL,
+			      0);
+	return err;
+}
+
+static int snd_microii_spdif_default_put(struct snd_kcontrol *kcontrol,
+					 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	unsigned int pval, pval_old;
+	int err;
+
+	pval = kcontrol->private_value;
+	pval_old = pval;
+	pval &= 0xfffff0f0;
+	pval |= (ucontrol->value.iec958.status[1] & 0x0f) << 8;
+	pval |= (ucontrol->value.iec958.status[0] & 0x0f);
+
+	pval &= 0xffff0fff;
+	pval |= (ucontrol->value.iec958.status[1] & 0xf0) << 8;
+
+	/* The frequency bits in AES3 cannot be set via register access. */
+
+	/* Silently ignore any bits from the request that cannot be set. */
+
+	if (pval == pval_old)
+		return 0;
+
+	kcontrol->private_value = pval;
+	err = snd_microii_spdif_default_update(list);
+	return err < 0 ? err : 1;
+}
+
+static int snd_microii_spdif_mask_get(struct snd_kcontrol *kcontrol,
+				      struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.iec958.status[0] = 0x0f;
+	ucontrol->value.iec958.status[1] = 0xff;
+	ucontrol->value.iec958.status[2] = 0x00;
+	ucontrol->value.iec958.status[3] = 0x00;
+
+	return 0;
+}
+
+static int snd_microii_spdif_switch_get(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = !(kcontrol->private_value & 0x02);
+
+	return 0;
+}
+
+static int snd_microii_spdif_switch_update(struct usb_mixer_elem_list *list)
+{
+	struct snd_usb_audio *chip = list->mixer->chip;
+	u8 reg = list->kctl->private_value;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0),
+			       UAC_SET_CUR,
+			       USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			       reg,
+			       9,
+			       NULL,
+			       0);
+}
+
+static int snd_microii_spdif_switch_put(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	u8 reg;
+	int err;
+
+	reg = ucontrol->value.integer.value[0] ? 0x28 : 0x2a;
+	if (reg == list->kctl->private_value)
+		return 0;
+
+	kcontrol->private_value = reg;
+	err = snd_microii_spdif_switch_update(list);
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new snd_microii_mixer_spdif[] = {
+	{
+		.iface =    SNDRV_CTL_ELEM_IFACE_PCM,
+		.name =     SNDRV_CTL_NAME_IEC958("", PLAYBACK, DEFAULT),
+		.info =     snd_microii_spdif_info,
+		.get =      snd_microii_spdif_default_get,
+		.put =      snd_microii_spdif_default_put,
+		.private_value = 0x00000100UL,/* reset value */
+	},
+	{
+		.access =   SNDRV_CTL_ELEM_ACCESS_READ,
+		.iface =    SNDRV_CTL_ELEM_IFACE_PCM,
+		.name =     SNDRV_CTL_NAME_IEC958("", PLAYBACK, MASK),
+		.info =     snd_microii_spdif_info,
+		.get =      snd_microii_spdif_mask_get,
+	},
+	{
+		.iface =    SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name =     SNDRV_CTL_NAME_IEC958("", PLAYBACK, SWITCH),
+		.info =     snd_ctl_boolean_mono_info,
+		.get =      snd_microii_spdif_switch_get,
+		.put =      snd_microii_spdif_switch_put,
+		.private_value = 0x00000028UL,/* reset value */
+	}
+};
+
+static int snd_microii_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err, i;
+	static const usb_mixer_elem_resume_func_t resume_funcs[] = {
+		snd_microii_spdif_default_update,
+		NULL,
+		snd_microii_spdif_switch_update
+	};
+
+	for (i = 0; i < ARRAY_SIZE(snd_microii_mixer_spdif); ++i) {
+		err = add_single_ctl_with_resume(mixer, 0,
+						 resume_funcs[i],
+						 &snd_microii_mixer_spdif[i],
+						 NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/* Creative Sound Blaster E1 */
+
+static int snd_soundblaster_e1_switch_get(struct snd_kcontrol *kcontrol,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = kcontrol->private_value;
+	return 0;
+}
+
+static int snd_soundblaster_e1_switch_update(struct usb_mixer_interface *mixer,
+					     unsigned char state)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	unsigned char buff[2];
+
+	buff[0] = 0x02;
+	buff[1] = state ? 0x02 : 0x00;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0), HID_REQ_SET_REPORT,
+			       USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
+			       0x0202, 3, buff, 2);
+}
+
+static int snd_soundblaster_e1_switch_put(struct snd_kcontrol *kcontrol,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	unsigned char value = !!ucontrol->value.integer.value[0];
+	unsigned long old_pval = kcontrol->private_value;
+	int err;
+
+	if (kcontrol->private_value == value)
+		return 0;
+	kcontrol->private_value = value;
+	err = snd_soundblaster_e1_switch_update(list->mixer, value);
+	if (err < 0) {
+		kcontrol->private_value = old_pval;
+		return err;
+	}
+	return 1;
+}
+
+static int snd_soundblaster_e1_switch_resume(struct usb_mixer_elem_list *list)
+{
+	return snd_soundblaster_e1_switch_update(list->mixer,
+						 list->kctl->private_value);
+}
+
+static int snd_soundblaster_e1_switch_info(struct snd_kcontrol *kcontrol,
+					   struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[2] = {
+		"Mic", "Aux"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static const struct snd_kcontrol_new snd_soundblaster_e1_input_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Input Source",
+	.info = snd_soundblaster_e1_switch_info,
+	.get = snd_soundblaster_e1_switch_get,
+	.put = snd_soundblaster_e1_switch_put,
+	.private_value = 0,
+};
+
+static int snd_soundblaster_e1_switch_create(struct usb_mixer_interface *mixer)
+{
+	return add_single_ctl_with_resume(mixer, 0,
+					  snd_soundblaster_e1_switch_resume,
+					  &snd_soundblaster_e1_input_switch,
+					  NULL);
+}
+
+/*
+ * Dell WD15 dock jack detection
+ *
+ * The WD15 contains an ALC4020 USB audio controller and ALC3263 audio codec
+ * from Realtek. It is a UAC 1 device, and UAC 1 does not support jack
+ * detection. Instead, jack detection works by sending HD Audio commands over
+ * vendor-type USB messages.
+ */
+
+#define HDA_VERB_CMD(V, N, D) (((N) << 20) | ((V) << 8) | (D))
+
+#define REALTEK_HDA_VALUE 0x0038
+
+#define REALTEK_HDA_SET		62
+#define REALTEK_MANUAL_MODE	72
+#define REALTEK_HDA_GET_OUT	88
+#define REALTEK_HDA_GET_IN	89
+
+#define REALTEK_AUDIO_FUNCTION_GROUP	0x01
+#define REALTEK_LINE1			0x1a
+#define REALTEK_VENDOR_REGISTERS	0x20
+#define REALTEK_HP_OUT			0x21
+
+#define REALTEK_CBJ_CTRL2 0x50
+
+#define REALTEK_JACK_INTERRUPT_NODE 5
+
+#define REALTEK_MIC_FLAG 0x100
+
+static int realtek_hda_set(struct snd_usb_audio *chip, u32 cmd)
+{
+	struct usb_device *dev = chip->dev;
+	__be32 buf = cpu_to_be32(cmd);
+
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), REALTEK_HDA_SET,
+			       USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_OUT,
+			       REALTEK_HDA_VALUE, 0, &buf, sizeof(buf));
+}
+
+static int realtek_hda_get(struct snd_usb_audio *chip, u32 cmd, u32 *value)
+{
+	struct usb_device *dev = chip->dev;
+	int err;
+	__be32 buf = cpu_to_be32(cmd);
+
+	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), REALTEK_HDA_GET_OUT,
+			      USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_OUT,
+			      REALTEK_HDA_VALUE, 0, &buf, sizeof(buf));
+	if (err < 0)
+		return err;
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), REALTEK_HDA_GET_IN,
+			      USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_IN,
+			      REALTEK_HDA_VALUE, 0, &buf, sizeof(buf));
+	if (err < 0)
+		return err;
+
+	*value = be32_to_cpu(buf);
+	return 0;
+}
+
+static int realtek_ctl_connector_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+	u32 pv = kcontrol->private_value;
+	u32 node_id = pv & 0xff;
+	u32 sense;
+	u32 cbj_ctrl2;
+	bool presence;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+	err = realtek_hda_get(chip,
+			      HDA_VERB_CMD(AC_VERB_GET_PIN_SENSE, node_id, 0),
+			      &sense);
+	if (err < 0)
+		return err;
+	if (pv & REALTEK_MIC_FLAG) {
+		err = realtek_hda_set(chip,
+				      HDA_VERB_CMD(AC_VERB_SET_COEF_INDEX,
+						   REALTEK_VENDOR_REGISTERS,
+						   REALTEK_CBJ_CTRL2));
+		if (err < 0)
+			return err;
+		err = realtek_hda_get(chip,
+				      HDA_VERB_CMD(AC_VERB_GET_PROC_COEF,
+						   REALTEK_VENDOR_REGISTERS, 0),
+				      &cbj_ctrl2);
+		if (err < 0)
+			return err;
+	}
+
+	presence = sense & AC_PINSENSE_PRESENCE;
+	if (pv & REALTEK_MIC_FLAG)
+		presence = presence && (cbj_ctrl2 & 0x0070) == 0x0070;
+	ucontrol->value.integer.value[0] = presence;
+	return 0;
+}
+
+static const struct snd_kcontrol_new realtek_connector_ctl_ro = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "", /* will be filled later manually */
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.info = snd_ctl_boolean_mono_info,
+	.get = realtek_ctl_connector_get,
+};
+
+static int realtek_resume_jack(struct usb_mixer_elem_list *list)
+{
+	snd_ctl_notify(list->mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &list->kctl->id);
+	return 0;
+}
+
+static int realtek_add_jack(struct usb_mixer_interface *mixer,
+			    char *name, u32 val, int unitid,
+			    const struct snd_kcontrol_new *kctl_new)
+{
+	struct usb_mixer_elem_info *cval;
+	struct snd_kcontrol *kctl;
+
+	cval = kzalloc_obj(*cval);
+	if (!cval)
+		return -ENOMEM;
+	snd_usb_mixer_elem_init_std(&cval->head, mixer, unitid);
+	cval->head.resume = realtek_resume_jack;
+	cval->val_type = USB_MIXER_BOOLEAN;
+	cval->channels = 1;
+	cval->min = 0;
+	cval->max = 1;
+	kctl = snd_ctl_new1(kctl_new, cval);
+	if (!kctl) {
+		kfree(cval);
+		return -ENOMEM;
+	}
+	kctl->private_value = val;
+	strscpy(kctl->id.name, name, sizeof(kctl->id.name));
+	kctl->private_free = snd_usb_mixer_elem_free;
+	return snd_usb_mixer_add_control(&cval->head, kctl);
+}
+
+static int dell_dock_mixer_create(struct usb_mixer_interface *mixer)
+{
+	int err;
+	struct usb_device *dev = mixer->chip->dev;
+
+	/* Power down the audio codec to avoid loud pops in the next step. */
+	realtek_hda_set(mixer->chip,
+			HDA_VERB_CMD(AC_VERB_SET_POWER_STATE,
+				     REALTEK_AUDIO_FUNCTION_GROUP,
+				     AC_PWRST_D3));
+
+	/*
+	 * Turn off 'manual mode' in case it was enabled. This removes the need
+	 * to power cycle the dock after it was attached to a Windows machine.
+	 */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), REALTEK_MANUAL_MODE,
+			USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_OUT,
+			0, 0, NULL, 0);
+
+	err = realtek_add_jack(mixer, "Line Out Jack", REALTEK_LINE1,
+			       REALTEK_JACK_INTERRUPT_NODE,
+			       &realtek_connector_ctl_ro);
+	if (err < 0)
+		return err;
+	err = realtek_add_jack(mixer, "Headphone Jack", REALTEK_HP_OUT,
+			       REALTEK_JACK_INTERRUPT_NODE,
+			       &realtek_connector_ctl_ro);
+	if (err < 0)
+		return err;
+	err = realtek_add_jack(mixer, "Headset Mic Jack",
+			       REALTEK_HP_OUT | REALTEK_MIC_FLAG,
+			       REALTEK_JACK_INTERRUPT_NODE,
+			       &realtek_connector_ctl_ro);
+	if (err < 0)
+		return err;
+	return 0;
+}
+
+static void dell_dock_init_vol(struct usb_mixer_interface *mixer, int ch, int id)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	u16 buf = 0;
+
+	snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC_SET_CUR,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			(UAC_FU_VOLUME << 8) | ch,
+			snd_usb_ctrl_intf(mixer->hostif) | (id << 8),
+			&buf, 2);
+}
+
+static int dell_dock_mixer_init(struct usb_mixer_interface *mixer)
+{
+	/* fix to 0dB playback volumes */
+	dell_dock_init_vol(mixer, 1, 16);
+	dell_dock_init_vol(mixer, 2, 16);
+	dell_dock_init_vol(mixer, 1, 19);
+	dell_dock_init_vol(mixer, 2, 19);
+	return 0;
+}
+
+/*
+ * HP Thunderbolt Dock G2 jack detection
+ *
+ * Similar to the Dell WD15/WD19, but with different commands.
+ */
+
+#define HP_DOCK_JACK_INTERRUPT_NODE	7
+
+#define HP_DOCK_GET			37
+
+#define HP_DOCK_JACK_PRESENCE		0xffb8
+#define HP_DOCK_JACK_PRESENCE_BIT	BIT(2)
+
+#define HP_DOCK_MIC_SENSE		0xf753
+#define HP_DOCK_MIC_SENSE_COMPLETE_BIT	BIT(4)
+
+#define HP_DOCK_MIC_SENSE_MASK		(BIT(2) | BIT(1) | BIT(0))
+/* #define HP_DOCK_MIC_SENSE_PRESENT	0x2 */
+#define HP_DOCK_MIC_SENSE_NOT_PRESENT	0x4
+
+static int hp_dock_ctl_connector_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *cval = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = cval->head.mixer->chip;
+	u32 pv = kcontrol->private_value;
+	bool presence;
+	int err;
+	u8 buf;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
+		       HP_DOCK_GET,
+		       USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_IN,
+		       0, HP_DOCK_JACK_PRESENCE, &buf, sizeof(buf));
+	if (err < 0)
+		return err;
+
+	presence = !(buf & HP_DOCK_JACK_PRESENCE_BIT);
+
+	if (pv && presence) {
+		for (int i = 0; i < 20; i++) {
+			err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
+			       HP_DOCK_GET,
+			       USB_RECIP_DEVICE | USB_TYPE_VENDOR | USB_DIR_IN,
+			       0, HP_DOCK_MIC_SENSE, &buf, sizeof(buf));
+			if (err < 0)
+				return err;
+
+			/* Mic sense is complete, we have a result. */
+			if (buf & HP_DOCK_MIC_SENSE_COMPLETE_BIT)
+				break;
+
+			msleep(100);
+		}
+
+		/*
+		 * If we reach the retry limit without mic sense having
+		 * completed, buf will contain HP_DOCK_MIC_SENSE_PRESENT,
+		 * thus presence remains true even when detection fails.
+		 */
+		if ((buf & HP_DOCK_MIC_SENSE_MASK) == HP_DOCK_MIC_SENSE_NOT_PRESENT)
+			presence = false;
+	}
+	ucontrol->value.integer.value[0] = presence;
+	return 0;
+}
+
+static const struct snd_kcontrol_new hp_dock_connector_ctl_ro = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "", /* will be filled later manually */
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.info = snd_ctl_boolean_mono_info,
+	.get = hp_dock_ctl_connector_get,
+};
+
+static int hp_dock_mixer_create(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	err = realtek_add_jack(mixer, "Headsets Playback Jack", 0,
+			       HP_DOCK_JACK_INTERRUPT_NODE,
+			       &hp_dock_connector_ctl_ro);
+	if (err < 0)
+		return err;
+
+	err = realtek_add_jack(mixer, "Headset Capture Jack", 1,
+			       HP_DOCK_JACK_INTERRUPT_NODE,
+			       &hp_dock_connector_ctl_ro);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+
+/* RME Class Compliant device quirks */
+
+#define SND_RME_GET_STATUS1			23
+#define SND_RME_GET_CURRENT_FREQ		17
+#define SND_RME_CLK_SYSTEM_SHIFT		16
+#define SND_RME_CLK_SYSTEM_MASK			0x1f
+#define SND_RME_CLK_AES_SHIFT			8
+#define SND_RME_CLK_SPDIF_SHIFT			12
+#define SND_RME_CLK_AES_SPDIF_MASK		0xf
+#define SND_RME_CLK_SYNC_SHIFT			6
+#define SND_RME_CLK_SYNC_MASK			0x3
+#define SND_RME_CLK_FREQMUL_SHIFT		18
+#define SND_RME_CLK_FREQMUL_MASK		0x7
+#define SND_RME_CLK_SYSTEM(x) \
+	(((x) >> SND_RME_CLK_SYSTEM_SHIFT) & SND_RME_CLK_SYSTEM_MASK)
+#define SND_RME_CLK_AES(x) \
+	(((x) >> SND_RME_CLK_AES_SHIFT) & SND_RME_CLK_AES_SPDIF_MASK)
+#define SND_RME_CLK_SPDIF(x) \
+	(((x) >> SND_RME_CLK_SPDIF_SHIFT) & SND_RME_CLK_AES_SPDIF_MASK)
+#define SND_RME_CLK_SYNC(x) \
+	(((x) >> SND_RME_CLK_SYNC_SHIFT) & SND_RME_CLK_SYNC_MASK)
+#define SND_RME_CLK_FREQMUL(x) \
+	(((x) >> SND_RME_CLK_FREQMUL_SHIFT) & SND_RME_CLK_FREQMUL_MASK)
+#define SND_RME_CLK_AES_LOCK			0x1
+#define SND_RME_CLK_AES_SYNC			0x4
+#define SND_RME_CLK_SPDIF_LOCK			0x2
+#define SND_RME_CLK_SPDIF_SYNC			0x8
+#define SND_RME_SPDIF_IF_SHIFT			4
+#define SND_RME_SPDIF_FORMAT_SHIFT		5
+#define SND_RME_BINARY_MASK			0x1
+#define SND_RME_SPDIF_IF(x) \
+	(((x) >> SND_RME_SPDIF_IF_SHIFT) & SND_RME_BINARY_MASK)
+#define SND_RME_SPDIF_FORMAT(x) \
+	(((x) >> SND_RME_SPDIF_FORMAT_SHIFT) & SND_RME_BINARY_MASK)
+
+static const u32 snd_rme_rate_table[] = {
+	32000, 44100, 48000, 50000,
+	64000, 88200, 96000, 100000,
+	128000, 176400, 192000, 200000,
+	256000,	352800, 384000, 400000,
+	512000, 705600, 768000, 800000
+};
+
+/* maximum number of items for AES and S/PDIF rates for above table */
+#define SND_RME_RATE_IDX_AES_SPDIF_NUM		12
+
+enum snd_rme_domain {
+	SND_RME_DOMAIN_SYSTEM,
+	SND_RME_DOMAIN_AES,
+	SND_RME_DOMAIN_SPDIF
+};
+
+enum snd_rme_clock_status {
+	SND_RME_CLOCK_NOLOCK,
+	SND_RME_CLOCK_LOCK,
+	SND_RME_CLOCK_SYNC
+};
+
+static int snd_rme_read_value(struct snd_usb_audio *chip,
+			      unsigned int item,
+			      u32 *value)
+{
+	struct usb_device *dev = chip->dev;
+	int err;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      item,
+			      USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			      0, 0,
+			      value, sizeof(*value));
+	if (err < 0)
+		dev_err(&dev->dev,
+			"unable to issue vendor read request %d (ret = %d)",
+			item, err);
+	return err;
+}
+
+static int snd_rme_get_status1(struct snd_kcontrol *kcontrol,
+			       u32 *status1)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = list->mixer->chip;
+
+	*status1 = 0;
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+	return snd_rme_read_value(chip, SND_RME_GET_STATUS1, status1);
+}
+
+static int snd_rme_rate_get(struct snd_kcontrol *kcontrol,
+			    struct snd_ctl_elem_value *ucontrol)
+{
+	u32 status1;
+	u32 rate = 0;
+	int idx;
+	int err;
+
+	err = snd_rme_get_status1(kcontrol, &status1);
+	if (err < 0)
+		return err;
+	switch (kcontrol->private_value) {
+	case SND_RME_DOMAIN_SYSTEM:
+		idx = SND_RME_CLK_SYSTEM(status1);
+		if (idx < ARRAY_SIZE(snd_rme_rate_table))
+			rate = snd_rme_rate_table[idx];
+		break;
+	case SND_RME_DOMAIN_AES:
+		idx = SND_RME_CLK_AES(status1);
+		if (idx < SND_RME_RATE_IDX_AES_SPDIF_NUM)
+			rate = snd_rme_rate_table[idx];
+		break;
+	case SND_RME_DOMAIN_SPDIF:
+		idx = SND_RME_CLK_SPDIF(status1);
+		if (idx < SND_RME_RATE_IDX_AES_SPDIF_NUM)
+			rate = snd_rme_rate_table[idx];
+		break;
+	default:
+		return -EINVAL;
+	}
+	ucontrol->value.integer.value[0] = rate;
+	return 0;
+}
+
+static int snd_rme_sync_state_get(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	u32 status1;
+	int idx = SND_RME_CLOCK_NOLOCK;
+	int err;
+
+	err = snd_rme_get_status1(kcontrol, &status1);
+	if (err < 0)
+		return err;
+	switch (kcontrol->private_value) {
+	case SND_RME_DOMAIN_AES:  /* AES */
+		if (status1 & SND_RME_CLK_AES_SYNC)
+			idx = SND_RME_CLOCK_SYNC;
+		else if (status1 & SND_RME_CLK_AES_LOCK)
+			idx = SND_RME_CLOCK_LOCK;
+		break;
+	case SND_RME_DOMAIN_SPDIF:  /* SPDIF */
+		if (status1 & SND_RME_CLK_SPDIF_SYNC)
+			idx = SND_RME_CLOCK_SYNC;
+		else if (status1 & SND_RME_CLK_SPDIF_LOCK)
+			idx = SND_RME_CLOCK_LOCK;
+		break;
+	default:
+		return -EINVAL;
+	}
+	ucontrol->value.enumerated.item[0] = idx;
+	return 0;
+}
+
+static int snd_rme_spdif_if_get(struct snd_kcontrol *kcontrol,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	u32 status1;
+	int err;
+
+	err = snd_rme_get_status1(kcontrol, &status1);
+	if (err < 0)
+		return err;
+	ucontrol->value.enumerated.item[0] = SND_RME_SPDIF_IF(status1);
+	return 0;
+}
+
+static int snd_rme_spdif_format_get(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	u32 status1;
+	int err;
+
+	err = snd_rme_get_status1(kcontrol, &status1);
+	if (err < 0)
+		return err;
+	ucontrol->value.enumerated.item[0] = SND_RME_SPDIF_FORMAT(status1);
+	return 0;
+}
+
+static int snd_rme_sync_source_get(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	u32 status1;
+	int err;
+
+	err = snd_rme_get_status1(kcontrol, &status1);
+	if (err < 0)
+		return err;
+	ucontrol->value.enumerated.item[0] = SND_RME_CLK_SYNC(status1);
+	return 0;
+}
+
+static int snd_rme_current_freq_get(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = list->mixer->chip;
+	u32 status1;
+	const u64 num = 104857600000000ULL;
+	u32 den;
+	unsigned int freq;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+	err = snd_rme_read_value(chip, SND_RME_GET_STATUS1, &status1);
+	if (err < 0)
+		return err;
+	err = snd_rme_read_value(chip, SND_RME_GET_CURRENT_FREQ, &den);
+	if (err < 0)
+		return err;
+	freq = (den == 0) ? 0 : div64_u64(num, den);
+	freq <<= SND_RME_CLK_FREQMUL(status1);
+	ucontrol->value.integer.value[0] = freq;
+	return 0;
+}
+
+static int snd_rme_rate_info(struct snd_kcontrol *kcontrol,
+			     struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	switch (kcontrol->private_value) {
+	case SND_RME_DOMAIN_SYSTEM:
+		uinfo->value.integer.min = 32000;
+		uinfo->value.integer.max = 800000;
+		break;
+	case SND_RME_DOMAIN_AES:
+	case SND_RME_DOMAIN_SPDIF:
+	default:
+		uinfo->value.integer.min = 0;
+		uinfo->value.integer.max = 200000;
+	}
+	uinfo->value.integer.step = 0;
+	return 0;
+}
+
+static int snd_rme_sync_state_info(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const sync_states[] = {
+		"No Lock", "Lock", "Sync"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1,
+				 ARRAY_SIZE(sync_states), sync_states);
+}
+
+static int snd_rme_spdif_if_info(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const spdif_if[] = {
+		"Coaxial", "Optical"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1,
+				 ARRAY_SIZE(spdif_if), spdif_if);
+}
+
+static int snd_rme_spdif_format_info(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const optical_type[] = {
+		"Consumer", "Professional"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1,
+				 ARRAY_SIZE(optical_type), optical_type);
+}
+
+static int snd_rme_sync_source_info(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const sync_sources[] = {
+		"Internal", "AES", "SPDIF", "Internal"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1,
+				 ARRAY_SIZE(sync_sources), sync_sources);
+}
+
+static const struct snd_kcontrol_new snd_rme_controls[] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "AES Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_rate_info,
+		.get = snd_rme_rate_get,
+		.private_value = SND_RME_DOMAIN_AES
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "AES Sync",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_sync_state_info,
+		.get = snd_rme_sync_state_get,
+		.private_value = SND_RME_DOMAIN_AES
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "SPDIF Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_rate_info,
+		.get = snd_rme_rate_get,
+		.private_value = SND_RME_DOMAIN_SPDIF
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "SPDIF Sync",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_sync_state_info,
+		.get = snd_rme_sync_state_get,
+		.private_value = SND_RME_DOMAIN_SPDIF
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "SPDIF Interface",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_spdif_if_info,
+		.get = snd_rme_spdif_if_get,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "SPDIF Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_spdif_format_info,
+		.get = snd_rme_spdif_format_get,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Sync Source",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_sync_source_info,
+		.get = snd_rme_sync_source_get
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "System Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_rate_info,
+		.get = snd_rme_rate_get,
+		.private_value = SND_RME_DOMAIN_SYSTEM
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Current Frequency",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_rate_info,
+		.get = snd_rme_current_freq_get
+	}
+};
+
+static int snd_rme_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err, i;
+
+	for (i = 0; i < ARRAY_SIZE(snd_rme_controls); ++i) {
+		err = add_single_ctl_with_resume(mixer, 0,
+						 NULL,
+						 &snd_rme_controls[i],
+						 NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/*
+ * RME Babyface Pro (FS)
+ *
+ * These devices exposes a couple of DSP functions via request to EP0.
+ * Switches are available via control registers, while routing is controlled
+ * by controlling the volume on each possible crossing point.
+ * Volume control is linear, from -inf (dec. 0) to +6dB (dec. 65536) with
+ * 0dB being at dec. 32768.
+ */
+enum {
+	SND_BBFPRO_CTL_REG1 = 0,
+	SND_BBFPRO_CTL_REG2
+};
+
+#define SND_BBFPRO_CTL_REG_MASK 1
+#define SND_BBFPRO_CTL_IDX_MASK 0xff
+#define SND_BBFPRO_CTL_IDX_SHIFT 1
+#define SND_BBFPRO_CTL_VAL_MASK 1
+#define SND_BBFPRO_CTL_VAL_SHIFT 9
+#define SND_BBFPRO_CTL_REG1_CLK_MASTER 0
+#define SND_BBFPRO_CTL_REG1_CLK_OPTICAL 1
+#define SND_BBFPRO_CTL_REG1_SPDIF_PRO 7
+#define SND_BBFPRO_CTL_REG1_SPDIF_EMPH 8
+#define SND_BBFPRO_CTL_REG1_SPDIF_OPTICAL 10
+#define SND_BBFPRO_CTL_REG2_48V_AN1 0
+#define SND_BBFPRO_CTL_REG2_48V_AN2 1
+#define SND_BBFPRO_CTL_REG2_SENS_IN3 2
+#define SND_BBFPRO_CTL_REG2_SENS_IN4 3
+#define SND_BBFPRO_CTL_REG2_PAD_AN1 4
+#define SND_BBFPRO_CTL_REG2_PAD_AN2 5
+
+#define SND_BBFPRO_MIXER_MAIN_OUT_CH_OFFSET 992
+#define SND_BBFPRO_MIXER_IDX_MASK 0x3ff
+#define SND_BBFPRO_MIXER_VAL_MASK 0x3ffff
+#define SND_BBFPRO_MIXER_VAL_SHIFT 9
+#define SND_BBFPRO_MIXER_VAL_MIN 0 // -inf
+#define SND_BBFPRO_MIXER_VAL_MAX 65536 // +6dB
+
+#define SND_BBFPRO_GAIN_CHANNEL_MASK 0x03
+#define SND_BBFPRO_GAIN_CHANNEL_SHIFT 7
+#define SND_BBFPRO_GAIN_VAL_MASK 0x7f
+#define SND_BBFPRO_GAIN_VAL_MIN 0
+#define SND_BBFPRO_GAIN_VAL_MIC_MAX 65
+#define SND_BBFPRO_GAIN_VAL_LINE_MAX 18 // 9db in 0.5db incraments
+
+#define SND_BBFPRO_USBREQ_CTL_REG1 0x10
+#define SND_BBFPRO_USBREQ_CTL_REG2 0x17
+#define SND_BBFPRO_USBREQ_GAIN 0x1a
+#define SND_BBFPRO_USBREQ_MIXER 0x12
+
+static int snd_bbfpro_ctl_update(struct usb_mixer_interface *mixer, u8 reg,
+				 u8 index, u8 value)
+{
+	u16 usb_req, usb_idx, usb_val;
+	struct snd_usb_audio *chip = mixer->chip;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	if (reg == SND_BBFPRO_CTL_REG1) {
+		usb_req = SND_BBFPRO_USBREQ_CTL_REG1;
+		if (index == SND_BBFPRO_CTL_REG1_CLK_OPTICAL) {
+			usb_idx = 3;
+			usb_val = value ? 3 : 0;
+		} else {
+			usb_idx = BIT(index);
+			usb_val = value ? usb_idx : 0;
+		}
+	} else {
+		usb_req = SND_BBFPRO_USBREQ_CTL_REG2;
+		usb_idx = BIT(index);
+		usb_val = value ? usb_idx : 0;
+	}
+
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0), usb_req,
+			       USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			       usb_val, usb_idx, NULL, 0);
+}
+
+static int snd_bbfpro_ctl_get(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	u8 reg, idx, val;
+	int pv;
+
+	pv = kcontrol->private_value;
+	reg = pv & SND_BBFPRO_CTL_REG_MASK;
+	idx = (pv >> SND_BBFPRO_CTL_IDX_SHIFT) & SND_BBFPRO_CTL_IDX_MASK;
+	val = kcontrol->private_value >> SND_BBFPRO_CTL_VAL_SHIFT;
+
+	if ((reg == SND_BBFPRO_CTL_REG1 &&
+	     idx == SND_BBFPRO_CTL_REG1_CLK_OPTICAL) ||
+	    (reg == SND_BBFPRO_CTL_REG2 &&
+	    (idx == SND_BBFPRO_CTL_REG2_SENS_IN3 ||
+	     idx == SND_BBFPRO_CTL_REG2_SENS_IN4))) {
+		ucontrol->value.enumerated.item[0] = val;
+	} else {
+		ucontrol->value.integer.value[0] = val;
+	}
+	return 0;
+}
+
+static int snd_bbfpro_ctl_info(struct snd_kcontrol *kcontrol,
+			       struct snd_ctl_elem_info *uinfo)
+{
+	u8 reg, idx;
+	int pv;
+
+	pv = kcontrol->private_value;
+	reg = pv & SND_BBFPRO_CTL_REG_MASK;
+	idx = (pv >> SND_BBFPRO_CTL_IDX_SHIFT) & SND_BBFPRO_CTL_IDX_MASK;
+
+	if (reg == SND_BBFPRO_CTL_REG1 &&
+	    idx == SND_BBFPRO_CTL_REG1_CLK_OPTICAL) {
+		static const char * const texts[2] = {
+			"AutoSync",
+			"Internal"
+		};
+		return snd_ctl_enum_info(uinfo, 1, 2, texts);
+	} else if (reg == SND_BBFPRO_CTL_REG2 &&
+		   (idx == SND_BBFPRO_CTL_REG2_SENS_IN3 ||
+		    idx == SND_BBFPRO_CTL_REG2_SENS_IN4)) {
+		static const char * const texts[2] = {
+			"-10dBV",
+			"+4dBu"
+		};
+		return snd_ctl_enum_info(uinfo, 1, 2, texts);
+	}
+
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 1;
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	return 0;
+}
+
+static int snd_bbfpro_ctl_put(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	int err;
+	u8 reg, idx;
+	int old_value, pv, val;
+
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+
+	pv = kcontrol->private_value;
+	reg = pv & SND_BBFPRO_CTL_REG_MASK;
+	idx = (pv >> SND_BBFPRO_CTL_IDX_SHIFT) & SND_BBFPRO_CTL_IDX_MASK;
+	old_value = (pv >> SND_BBFPRO_CTL_VAL_SHIFT) & SND_BBFPRO_CTL_VAL_MASK;
+
+	if ((reg == SND_BBFPRO_CTL_REG1 &&
+	     idx == SND_BBFPRO_CTL_REG1_CLK_OPTICAL) ||
+	    (reg == SND_BBFPRO_CTL_REG2 &&
+	    (idx == SND_BBFPRO_CTL_REG2_SENS_IN3 ||
+	     idx == SND_BBFPRO_CTL_REG2_SENS_IN4))) {
+		val = ucontrol->value.enumerated.item[0];
+	} else {
+		val = ucontrol->value.integer.value[0];
+	}
+
+	if (val > 1)
+		return -EINVAL;
+
+	if (val == old_value)
+		return 0;
+
+	err = snd_bbfpro_ctl_update(mixer, reg, idx, val);
+	if (err < 0)
+		return err;
+
+	kcontrol->private_value = reg
+		| ((idx & SND_BBFPRO_CTL_IDX_MASK) << SND_BBFPRO_CTL_IDX_SHIFT)
+		| ((val & SND_BBFPRO_CTL_VAL_MASK) << SND_BBFPRO_CTL_VAL_SHIFT);
+	return 1;
+}
+
+static int snd_bbfpro_ctl_resume(struct usb_mixer_elem_list *list)
+{
+	u8 reg, idx;
+	int value, pv;
+
+	pv = list->kctl->private_value;
+	reg = pv & SND_BBFPRO_CTL_REG_MASK;
+	idx = (pv >> SND_BBFPRO_CTL_IDX_SHIFT) & SND_BBFPRO_CTL_IDX_MASK;
+	value = (pv >> SND_BBFPRO_CTL_VAL_SHIFT) & SND_BBFPRO_CTL_VAL_MASK;
+
+	return snd_bbfpro_ctl_update(list->mixer, reg, idx, value);
+}
+
+static int snd_bbfpro_gain_update(struct usb_mixer_interface *mixer,
+				  u8 channel, u8 gain)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+
+	if (channel < 2) {
+		// XLR preamp: 3-bit fine, 5-bit coarse; special case >60
+		if (gain < 60)
+			gain = ((gain % 3) << 5) | (gain / 3);
+		else
+			gain = ((gain % 6) << 5) | (60 / 3);
+	}
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0),
+			       SND_BBFPRO_USBREQ_GAIN,
+			       USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			       gain, channel, NULL, 0);
+}
+
+static int snd_bbfpro_gain_get(struct snd_kcontrol *kcontrol,
+			       struct snd_ctl_elem_value *ucontrol)
+{
+	int value = kcontrol->private_value & SND_BBFPRO_GAIN_VAL_MASK;
+
+	ucontrol->value.integer.value[0] = value;
+	return 0;
+}
+
+static int snd_bbfpro_gain_info(struct snd_kcontrol *kcontrol,
+				struct snd_ctl_elem_info *uinfo)
+{
+	int pv, channel;
+
+	pv = kcontrol->private_value;
+	channel = (pv >> SND_BBFPRO_GAIN_CHANNEL_SHIFT) &
+		SND_BBFPRO_GAIN_CHANNEL_MASK;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = SND_BBFPRO_GAIN_VAL_MIN;
+
+	if (channel < 2)
+		uinfo->value.integer.max = SND_BBFPRO_GAIN_VAL_MIC_MAX;
+	else
+		uinfo->value.integer.max = SND_BBFPRO_GAIN_VAL_LINE_MAX;
+
+	return 0;
+}
+
+static int snd_bbfpro_gain_put(struct snd_kcontrol *kcontrol,
+			       struct snd_ctl_elem_value *ucontrol)
+{
+	int pv, channel, old_value, value, err;
+
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+
+	pv = kcontrol->private_value;
+	channel = (pv >> SND_BBFPRO_GAIN_CHANNEL_SHIFT) &
+		SND_BBFPRO_GAIN_CHANNEL_MASK;
+	old_value = pv & SND_BBFPRO_GAIN_VAL_MASK;
+	value = ucontrol->value.integer.value[0];
+
+	if (value < SND_BBFPRO_GAIN_VAL_MIN)
+		return -EINVAL;
+
+	if (channel < 2) {
+		if (value > SND_BBFPRO_GAIN_VAL_MIC_MAX)
+			return -EINVAL;
+	} else {
+		if (value > SND_BBFPRO_GAIN_VAL_LINE_MAX)
+			return -EINVAL;
+	}
+
+	if (value == old_value)
+		return 0;
+
+	err = snd_bbfpro_gain_update(mixer, channel, value);
+	if (err < 0)
+		return err;
+
+	kcontrol->private_value =
+		(channel << SND_BBFPRO_GAIN_CHANNEL_SHIFT) | value;
+	return 1;
+}
+
+static int snd_bbfpro_gain_resume(struct usb_mixer_elem_list *list)
+{
+	int pv, channel, value;
+	struct snd_kcontrol *kctl = list->kctl;
+
+	pv = kctl->private_value;
+	channel = (pv >> SND_BBFPRO_GAIN_CHANNEL_SHIFT) &
+		SND_BBFPRO_GAIN_CHANNEL_MASK;
+	value = pv & SND_BBFPRO_GAIN_VAL_MASK;
+
+	return snd_bbfpro_gain_update(list->mixer, channel, value);
+}
+
+static int snd_bbfpro_vol_update(struct usb_mixer_interface *mixer, u16 index,
+				 u32 value)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	u16 idx;
+	u16 usb_idx, usb_val;
+	u32 v;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+
+	idx = index & SND_BBFPRO_MIXER_IDX_MASK;
+	// 18 bit linear volume, split so 2 bits end up in index.
+	v = value & SND_BBFPRO_MIXER_VAL_MASK;
+	usb_idx = idx | (v & 0x3) << 14;
+	usb_val = (v >> 2) & 0xffff;
+
+	return snd_usb_ctl_msg(chip->dev,
+			       usb_sndctrlpipe(chip->dev, 0),
+			       SND_BBFPRO_USBREQ_MIXER,
+			       USB_DIR_OUT | USB_TYPE_VENDOR |
+			       USB_RECIP_DEVICE,
+			       usb_val, usb_idx, NULL, 0);
+}
+
+static int snd_bbfpro_vol_get(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] =
+		kcontrol->private_value >> SND_BBFPRO_MIXER_VAL_SHIFT;
+	return 0;
+}
+
+static int snd_bbfpro_vol_info(struct snd_kcontrol *kcontrol,
+			       struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = SND_BBFPRO_MIXER_VAL_MIN;
+	uinfo->value.integer.max = SND_BBFPRO_MIXER_VAL_MAX;
+	return 0;
+}
+
+static int snd_bbfpro_vol_put(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	int err;
+	u16 idx;
+	u32 new_val, old_value, uvalue;
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct usb_mixer_interface *mixer = list->mixer;
+
+	uvalue = ucontrol->value.integer.value[0];
+	idx = kcontrol->private_value & SND_BBFPRO_MIXER_IDX_MASK;
+	old_value = kcontrol->private_value >> SND_BBFPRO_MIXER_VAL_SHIFT;
+
+	if (uvalue > SND_BBFPRO_MIXER_VAL_MAX)
+		return -EINVAL;
+
+	if (uvalue == old_value)
+		return 0;
+
+	new_val = uvalue & SND_BBFPRO_MIXER_VAL_MASK;
+
+	err = snd_bbfpro_vol_update(mixer, idx, new_val);
+	if (err < 0)
+		return err;
+
+	kcontrol->private_value = idx
+		| (new_val << SND_BBFPRO_MIXER_VAL_SHIFT);
+	return 1;
+}
+
+static int snd_bbfpro_vol_resume(struct usb_mixer_elem_list *list)
+{
+	int pv = list->kctl->private_value;
+	u16 idx = pv & SND_BBFPRO_MIXER_IDX_MASK;
+	u32 val = (pv >> SND_BBFPRO_MIXER_VAL_SHIFT)
+		& SND_BBFPRO_MIXER_VAL_MASK;
+	return snd_bbfpro_vol_update(list->mixer, idx, val);
+}
+
+// Predfine elements
+static const struct snd_kcontrol_new snd_bbfpro_ctl_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.index = 0,
+	.info = snd_bbfpro_ctl_info,
+	.get = snd_bbfpro_ctl_get,
+	.put = snd_bbfpro_ctl_put
+};
+
+static const struct snd_kcontrol_new snd_bbfpro_gain_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.index = 0,
+	.info = snd_bbfpro_gain_info,
+	.get = snd_bbfpro_gain_get,
+	.put = snd_bbfpro_gain_put
+};
+
+static const struct snd_kcontrol_new snd_bbfpro_vol_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.index = 0,
+	.info = snd_bbfpro_vol_info,
+	.get = snd_bbfpro_vol_get,
+	.put = snd_bbfpro_vol_put
+};
+
+static int snd_bbfpro_ctl_add(struct usb_mixer_interface *mixer, u8 reg,
+			      u8 index, char *name)
+{
+	struct snd_kcontrol_new knew = snd_bbfpro_ctl_control;
+
+	knew.name = name;
+	knew.private_value = (reg & SND_BBFPRO_CTL_REG_MASK)
+		| ((index & SND_BBFPRO_CTL_IDX_MASK)
+			<< SND_BBFPRO_CTL_IDX_SHIFT);
+
+	return add_single_ctl_with_resume(mixer, 0, snd_bbfpro_ctl_resume,
+		&knew, NULL);
+}
+
+static int snd_bbfpro_gain_add(struct usb_mixer_interface *mixer, u8 channel,
+			       char *name)
+{
+	struct snd_kcontrol_new knew = snd_bbfpro_gain_control;
+
+	knew.name = name;
+	knew.private_value = channel << SND_BBFPRO_GAIN_CHANNEL_SHIFT;
+
+	return add_single_ctl_with_resume(mixer, 0, snd_bbfpro_gain_resume,
+		&knew, NULL);
+}
+
+static int snd_bbfpro_vol_add(struct usb_mixer_interface *mixer, u16 index,
+			      char *name)
+{
+	struct snd_kcontrol_new knew = snd_bbfpro_vol_control;
+
+	knew.name = name;
+	knew.private_value = index & SND_BBFPRO_MIXER_IDX_MASK;
+
+	return add_single_ctl_with_resume(mixer, 0, snd_bbfpro_vol_resume,
+		&knew, NULL);
+}
+
+static int snd_bbfpro_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err, i, o;
+	char name[48];
+
+	static const char * const input[] = {
+		"AN1", "AN2", "IN3", "IN4", "AS1", "AS2", "ADAT3",
+		"ADAT4", "ADAT5", "ADAT6", "ADAT7", "ADAT8"};
+
+	static const char * const output[] = {
+		"AN1", "AN2", "PH3", "PH4", "AS1", "AS2", "ADAT3", "ADAT4",
+		"ADAT5", "ADAT6", "ADAT7", "ADAT8"};
+
+	for (o = 0 ; o < 12 ; ++o) {
+		for (i = 0 ; i < 12 ; ++i) {
+			// Line routing
+			snprintf(name, sizeof(name),
+				 "%s-%s-%s Playback Volume",
+				 (i < 2 ? "Mic" : "Line"),
+				 input[i], output[o]);
+			err = snd_bbfpro_vol_add(mixer, (26 * o + i), name);
+			if (err < 0)
+				return err;
+
+			// PCM routing... yes, it is output remapping
+			snprintf(name, sizeof(name),
+				 "PCM-%s-%s Playback Volume",
+				 output[i], output[o]);
+			err = snd_bbfpro_vol_add(mixer, (26 * o + 12 + i),
+						 name);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	// Main out volume
+	for (i = 0 ; i < 12 ; ++i) {
+		snprintf(name, sizeof(name), "Main-Out %s", output[i]);
+		// Main outs are offset to 992
+		err = snd_bbfpro_vol_add(mixer,
+					 i + SND_BBFPRO_MIXER_MAIN_OUT_CH_OFFSET,
+					 name);
+		if (err < 0)
+			return err;
+	}
+
+	// Input gain
+	for (i = 0 ; i < 4 ; ++i) {
+		if (i < 2)
+			snprintf(name, sizeof(name), "Mic-%s Gain", input[i]);
+		else
+			snprintf(name, sizeof(name), "Line-%s Gain", input[i]);
+
+		err = snd_bbfpro_gain_add(mixer, i, name);
+		if (err < 0)
+			return err;
+	}
+
+	// Control Reg 1
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG1,
+				 SND_BBFPRO_CTL_REG1_CLK_OPTICAL,
+				 "Sample Clock Source");
+	if (err < 0)
+		return err;
+
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG1,
+				 SND_BBFPRO_CTL_REG1_SPDIF_PRO,
+				 "IEC958 Pro Mask");
+	if (err < 0)
+		return err;
+
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG1,
+				 SND_BBFPRO_CTL_REG1_SPDIF_EMPH,
+				 "IEC958 Emphasis");
+	if (err < 0)
+		return err;
+
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG1,
+				 SND_BBFPRO_CTL_REG1_SPDIF_OPTICAL,
+				 "IEC958 Switch");
+	if (err < 0)
+		return err;
+
+	// Control Reg 2
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG2,
+				 SND_BBFPRO_CTL_REG2_48V_AN1,
+				 "Mic-AN1 48V");
+	if (err < 0)
+		return err;
+
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG2,
+				 SND_BBFPRO_CTL_REG2_48V_AN2,
+				 "Mic-AN2 48V");
+	if (err < 0)
+		return err;
+
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG2,
+				 SND_BBFPRO_CTL_REG2_SENS_IN3,
+				 "Line-IN3 Sens.");
+	if (err < 0)
+		return err;
+
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG2,
+				 SND_BBFPRO_CTL_REG2_SENS_IN4,
+				 "Line-IN4 Sens.");
+	if (err < 0)
+		return err;
+
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG2,
+				 SND_BBFPRO_CTL_REG2_PAD_AN1,
+				 "Mic-AN1 PAD");
+	if (err < 0)
+		return err;
+
+	err = snd_bbfpro_ctl_add(mixer, SND_BBFPRO_CTL_REG2,
+				 SND_BBFPRO_CTL_REG2_PAD_AN2,
+				 "Mic-AN2 PAD");
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/*
+ * RME Digiface USB
+ */
+
+#define RME_DIGIFACE_READ_STATUS 17
+#define RME_DIGIFACE_STATUS_REG0L 0
+#define RME_DIGIFACE_STATUS_REG0H 1
+#define RME_DIGIFACE_STATUS_REG1L 2
+#define RME_DIGIFACE_STATUS_REG1H 3
+#define RME_DIGIFACE_STATUS_REG2L 4
+#define RME_DIGIFACE_STATUS_REG2H 5
+#define RME_DIGIFACE_STATUS_REG3L 6
+#define RME_DIGIFACE_STATUS_REG3H 7
+
+#define RME_DIGIFACE_CTL_REG1 16
+#define RME_DIGIFACE_CTL_REG2 18
+
+/* Reg is overloaded, 0-7 for status halfwords or 16 or 18 for control registers */
+#define RME_DIGIFACE_REGISTER(reg, mask) (((reg) << 16) | (mask))
+#define RME_DIGIFACE_INVERT BIT(31)
+
+static int snd_rme_digiface_write_reg(struct snd_kcontrol *kcontrol, int item, u16 mask, u16 val)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = list->mixer->chip;
+	struct usb_device *dev = chip->dev;
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			      item,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			      val, mask, NULL, 0);
+	if (err < 0)
+		dev_err(&dev->dev,
+			"unable to issue control set request %d (ret = %d)",
+			item, err);
+	return err;
+}
+
+static int snd_rme_digiface_read_status(struct snd_kcontrol *kcontrol, u32 status[4])
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = list->mixer->chip;
+	struct usb_device *dev = chip->dev;
+	__le32 buf[4] = {};
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      RME_DIGIFACE_READ_STATUS,
+			      USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			      0, 0,
+			      buf, sizeof(buf));
+	if (err < 0) {
+		dev_err(&dev->dev,
+			"unable to issue status read request (ret = %d)",
+			err);
+	} else {
+		for (int i = 0; i < ARRAY_SIZE(buf); i++)
+			status[i] = le32_to_cpu(buf[i]);
+	}
+	return err;
+}
+
+static int snd_rme_digiface_get_status_val(struct snd_kcontrol *kcontrol)
+{
+	int err;
+	u32 status[4];
+	bool invert = kcontrol->private_value & RME_DIGIFACE_INVERT;
+	u8 reg = (kcontrol->private_value >> 16) & 0xff;
+	u16 mask = kcontrol->private_value & 0xffff;
+	u16 val;
+
+	err = snd_rme_digiface_read_status(kcontrol, status);
+	if (err < 0)
+		return err;
+
+	switch (reg) {
+	/* Status register halfwords */
+	case RME_DIGIFACE_STATUS_REG0L ... RME_DIGIFACE_STATUS_REG3H:
+		break;
+	case RME_DIGIFACE_CTL_REG1: /* Control register 1, present in halfword 3L */
+		reg = RME_DIGIFACE_STATUS_REG3L;
+		break;
+	case RME_DIGIFACE_CTL_REG2: /* Control register 2, present in halfword 3H */
+		reg = RME_DIGIFACE_STATUS_REG3H;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (reg & 1)
+		val = status[reg >> 1] >> 16;
+	else
+		val = status[reg >> 1] & 0xffff;
+
+	if (invert)
+		val ^= mask;
+
+	return field_get(mask, val);
+}
+
+static int snd_rme_digiface_rate_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	int freq = snd_rme_digiface_get_status_val(kcontrol);
+
+	if (freq < 0)
+		return freq;
+	if (freq >= ARRAY_SIZE(snd_rme_rate_table))
+		return -EIO;
+
+	ucontrol->value.integer.value[0] = snd_rme_rate_table[freq];
+	return 0;
+}
+
+static int snd_rme_digiface_enum_get(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	int val = snd_rme_digiface_get_status_val(kcontrol);
+
+	if (val < 0)
+		return val;
+
+	ucontrol->value.enumerated.item[0] = val;
+	return 0;
+}
+
+static int snd_rme_digiface_enum_put(struct snd_kcontrol *kcontrol,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	bool invert = kcontrol->private_value & RME_DIGIFACE_INVERT;
+	u8 reg = (kcontrol->private_value >> 16) & 0xff;
+	u16 mask = kcontrol->private_value & 0xffff;
+	u16 val = field_prep(mask, ucontrol->value.enumerated.item[0]);
+
+	if (invert)
+		val ^= mask;
+
+	return snd_rme_digiface_write_reg(kcontrol, reg, mask, val);
+}
+
+static int snd_rme_digiface_current_sync_get(struct snd_kcontrol *kcontrol,
+					     struct snd_ctl_elem_value *ucontrol)
+{
+	int ret = snd_rme_digiface_enum_get(kcontrol, ucontrol);
+
+	/* 7 means internal for current sync */
+	if (ucontrol->value.enumerated.item[0] == 7)
+		ucontrol->value.enumerated.item[0] = 0;
+
+	return ret;
+}
+
+static int snd_rme_digiface_sync_state_get(struct snd_kcontrol *kcontrol,
+					   struct snd_ctl_elem_value *ucontrol)
+{
+	u32 status[4];
+	int err;
+	bool valid, sync;
+
+	err = snd_rme_digiface_read_status(kcontrol, status);
+	if (err < 0)
+		return err;
+
+	valid = status[0] & BIT(kcontrol->private_value);
+	sync = status[0] & BIT(5 + kcontrol->private_value);
+
+	if (!valid)
+		ucontrol->value.enumerated.item[0] = SND_RME_CLOCK_NOLOCK;
+	else if (!sync)
+		ucontrol->value.enumerated.item[0] = SND_RME_CLOCK_LOCK;
+	else
+		ucontrol->value.enumerated.item[0] = SND_RME_CLOCK_SYNC;
+	return 0;
+}
+
+static int snd_rme_digiface_format_info(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const format[] = {
+		"ADAT", "S/PDIF"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1,
+				 ARRAY_SIZE(format), format);
+}
+
+static int snd_rme_digiface_sync_source_info(struct snd_kcontrol *kcontrol,
+					     struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const sync_sources[] = {
+		"Internal", "Input 1", "Input 2", "Input 3", "Input 4"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1,
+				 ARRAY_SIZE(sync_sources), sync_sources);
+}
+
+static int snd_rme_digiface_rate_info(struct snd_kcontrol *kcontrol,
+				      struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 200000;
+	uinfo->value.integer.step = 0;
+	return 0;
+}
+
+static const struct snd_kcontrol_new snd_rme_digiface_controls[] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 1 Sync",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_sync_state_info,
+		.get = snd_rme_digiface_sync_state_get,
+		.private_value = 0,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 1 Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_format_info,
+		.get = snd_rme_digiface_enum_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG0H, BIT(0)) |
+			RME_DIGIFACE_INVERT,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 1 Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_rate_info,
+		.get = snd_rme_digiface_rate_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG1L, GENMASK(3, 0)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 2 Sync",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_sync_state_info,
+		.get = snd_rme_digiface_sync_state_get,
+		.private_value = 1,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 2 Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_format_info,
+		.get = snd_rme_digiface_enum_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG0L, BIT(13)) |
+			RME_DIGIFACE_INVERT,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 2 Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_rate_info,
+		.get = snd_rme_digiface_rate_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG1L, GENMASK(7, 4)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 3 Sync",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_sync_state_info,
+		.get = snd_rme_digiface_sync_state_get,
+		.private_value = 2,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 3 Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_format_info,
+		.get = snd_rme_digiface_enum_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG0L, BIT(14)) |
+			RME_DIGIFACE_INVERT,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 3 Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_rate_info,
+		.get = snd_rme_digiface_rate_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG1L, GENMASK(11, 8)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 4 Sync",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_sync_state_info,
+		.get = snd_rme_digiface_sync_state_get,
+		.private_value = 3,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 4 Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_format_info,
+		.get = snd_rme_digiface_enum_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG0L, GENMASK(15, 12)) |
+			RME_DIGIFACE_INVERT,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Input 4 Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_rate_info,
+		.get = snd_rme_digiface_rate_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG1L, GENMASK(3, 0)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Output 1 Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_rme_digiface_format_info,
+		.get = snd_rme_digiface_enum_get,
+		.put = snd_rme_digiface_enum_put,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_CTL_REG2, BIT(0)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Output 2 Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_rme_digiface_format_info,
+		.get = snd_rme_digiface_enum_get,
+		.put = snd_rme_digiface_enum_put,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_CTL_REG2, BIT(1)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Output 3 Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_rme_digiface_format_info,
+		.get = snd_rme_digiface_enum_get,
+		.put = snd_rme_digiface_enum_put,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_CTL_REG2, BIT(3)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Output 4 Format",
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_rme_digiface_format_info,
+		.get = snd_rme_digiface_enum_get,
+		.put = snd_rme_digiface_enum_put,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_CTL_REG2, BIT(4)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Sync Source",
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.info = snd_rme_digiface_sync_source_info,
+		.get = snd_rme_digiface_enum_get,
+		.put = snd_rme_digiface_enum_put,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_CTL_REG1, GENMASK(2, 0)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Current Sync Source",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_digiface_sync_source_info,
+		.get = snd_rme_digiface_current_sync_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG0L, GENMASK(12, 10)),
+	},
+	{
+		/*
+		 * This is writeable, but it is only set by the PCM rate.
+		 * Mixer apps currently need to drive the mixer using raw USB requests,
+		 * so they can also change this that way to configure the rate for
+		 * stand-alone operation when the PCM is closed.
+		 */
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "System Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_rate_info,
+		.get = snd_rme_digiface_rate_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_CTL_REG1, GENMASK(6, 3)),
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "Current Rate",
+		.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.info = snd_rme_rate_info,
+		.get = snd_rme_digiface_rate_get,
+		.private_value = RME_DIGIFACE_REGISTER(RME_DIGIFACE_STATUS_REG1H, GENMASK(7, 4)),
+	}
+};
+
+static int snd_rme_digiface_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err, i;
+
+	for (i = 0; i < ARRAY_SIZE(snd_rme_digiface_controls); ++i) {
+		err = add_single_ctl_with_resume(mixer, 0,
+						 NULL,
+						 &snd_rme_digiface_controls[i],
+						 NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/*
+ * Pioneer DJ / AlphaTheta DJM Mixers
+ *
+ * These devices generally have options for soft-switching the playback and
+ * capture sources in addition to the recording level. Although different
+ * devices have different configurations, there seems to be canonical values
+ * for specific capture/playback types:  See the definitions of these below.
+ *
+ * The wValue is masked with the stereo channel number. e.g. Setting Ch2 to
+ * capture phono would be 0x0203. Capture, playback and capture level have
+ * different wIndexes.
+ */
+
+// Capture types
+#define SND_DJM_CAP_LINE	0x00
+#define SND_DJM_CAP_CDLINE	0x01
+#define SND_DJM_CAP_DIGITAL	0x02
+#define SND_DJM_CAP_PHONO	0x03
+#define SND_DJM_CAP_PREFADER	0x05
+#define SND_DJM_CAP_PFADER	0x06
+#define SND_DJM_CAP_XFADERA	0x07
+#define SND_DJM_CAP_XFADERB	0x08
+#define SND_DJM_CAP_MIC		0x09
+#define SND_DJM_CAP_AUX		0x0d
+#define SND_DJM_CAP_RECOUT	0x0a
+#define SND_DJM_CAP_RECOUT_NOMIC	0x0e
+#define SND_DJM_CAP_NONE	0x0f
+#define SND_DJM_CAP_FXSEND	0x10
+#define SND_DJM_CAP_CH1PFADER	0x11
+#define SND_DJM_CAP_CH2PFADER	0x12
+#define SND_DJM_CAP_CH3PFADER	0x13
+#define SND_DJM_CAP_CH4PFADER	0x14
+#define SND_DJM_CAP_EXT1SEND	0x21
+#define SND_DJM_CAP_EXT2SEND	0x22
+#define SND_DJM_CAP_CH1PREFADER	0x31
+#define SND_DJM_CAP_CH2PREFADER	0x32
+#define SND_DJM_CAP_CH3PREFADER	0x33
+#define SND_DJM_CAP_CH4PREFADER	0x34
+
+// Playback types
+#define SND_DJM_PB_CH1		0x00
+#define SND_DJM_PB_CH2		0x01
+#define SND_DJM_PB_AUX		0x04
+
+#define SND_DJM_WINDEX_CAP	0x8002
+#define SND_DJM_WINDEX_CAPLVL	0x8003
+#define SND_DJM_WINDEX_PB	0x8016
+
+// kcontrol->private_value layout
+#define SND_DJM_VALUE_MASK	0x0000ffff
+#define SND_DJM_GROUP_MASK	0x00ff0000
+#define SND_DJM_DEVICE_MASK	0xff000000
+#define SND_DJM_GROUP_SHIFT	16
+#define SND_DJM_DEVICE_SHIFT	24
+
+// device table index
+// used for the snd_djm_devices table, so please update accordingly
+#define SND_DJM_250MK2_IDX	0x0
+#define SND_DJM_750_IDX		0x1
+#define SND_DJM_850_IDX		0x2
+#define SND_DJM_900NXS2_IDX	0x3
+#define SND_DJM_750MK2_IDX	0x4
+#define SND_DJM_450_IDX		0x5
+#define SND_DJM_A9_IDX		0x6
+#define SND_DJM_V10_IDX	0x7
+#define SND_DJM_S11_IDX	0x8
+
+#define SND_DJM_CTL(_name, suffix, _default_value, _windex) { \
+	.name = _name, \
+	.options = snd_djm_opts_##suffix, \
+	.noptions = ARRAY_SIZE(snd_djm_opts_##suffix), \
+	.default_value = _default_value, \
+	.wIndex = _windex }
+
+#define SND_DJM_DEVICE(suffix) { \
+	.controls = snd_djm_ctls_##suffix, \
+	.ncontrols = ARRAY_SIZE(snd_djm_ctls_##suffix) }
+
+struct snd_djm_device {
+	const char *name;
+	const struct snd_djm_ctl *controls;
+	size_t ncontrols;
+};
+
+struct snd_djm_ctl {
+	const char *name;
+	const u16 *options;
+	size_t noptions;
+	u16 default_value;
+	u16 wIndex;
+};
+
+static const char *snd_djm_get_label_caplevel_common(u16 wvalue)
+{
+	switch (wvalue) {
+	case 0x0000:	return "-19dB";
+	case 0x0100:	return "-15dB";
+	case 0x0200:	return "-10dB";
+	case 0x0300:	return "-5dB";
+	default:	return NULL;
+	}
+};
+
+// Models like DJM-A9 or DJM-V10 have different capture levels than others
+static const char *snd_djm_get_label_caplevel_high(u16 wvalue)
+{
+	switch (wvalue) {
+	case 0x0000:	return "+15dB";
+	case 0x0100:	return "+12dB";
+	case 0x0200:	return "+9dB";
+	case 0x0300:	return "+6dB";
+	case 0x0400:	return "+3dB";
+	case 0x0500:	return "0dB";
+	default:	return NULL;
+	}
+};
+
+static const char *snd_djm_get_label_cap_common(u16 wvalue)
+{
+	switch (wvalue & 0x00ff) {
+	case SND_DJM_CAP_LINE:		return "Control Tone LINE";
+	case SND_DJM_CAP_CDLINE:	return "Control Tone CD/LINE";
+	case SND_DJM_CAP_DIGITAL:	return "Control Tone DIGITAL";
+	case SND_DJM_CAP_PHONO:		return "Control Tone PHONO";
+	case SND_DJM_CAP_PFADER:	return "Post Fader";
+	case SND_DJM_CAP_XFADERA:	return "Cross Fader A";
+	case SND_DJM_CAP_XFADERB:	return "Cross Fader B";
+	case SND_DJM_CAP_MIC:		return "Mic";
+	case SND_DJM_CAP_RECOUT:	return "Rec Out";
+	case SND_DJM_CAP_RECOUT_NOMIC:	return "Rec Out without Mic";
+	case SND_DJM_CAP_AUX:		return "Aux";
+	case SND_DJM_CAP_NONE:		return "None";
+	case SND_DJM_CAP_FXSEND:	return "FX SEND";
+	case SND_DJM_CAP_CH1PREFADER:	return "Pre Fader Ch1";
+	case SND_DJM_CAP_CH2PREFADER:	return "Pre Fader Ch2";
+	case SND_DJM_CAP_CH3PREFADER:	return "Pre Fader Ch3";
+	case SND_DJM_CAP_CH4PREFADER:	return "Pre Fader Ch4";
+	case SND_DJM_CAP_CH1PFADER:	return "Post Fader Ch1";
+	case SND_DJM_CAP_CH2PFADER:	return "Post Fader Ch2";
+	case SND_DJM_CAP_CH3PFADER:	return "Post Fader Ch3";
+	case SND_DJM_CAP_CH4PFADER:	return "Post Fader Ch4";
+	case SND_DJM_CAP_EXT1SEND:	return "EXT1 SEND";
+	case SND_DJM_CAP_EXT2SEND:	return "EXT2 SEND";
+	default:			return NULL;
+	}
+};
+
+// The DJM-850 has different values for CD/LINE and LINE capture
+// control options than the other DJM declared in this file.
+static const char *snd_djm_get_label_cap_850(u16 wvalue)
+{
+	switch (wvalue & 0x00ff) {
+	case 0x00:		return "Control Tone CD/LINE";
+	case 0x01:		return "Control Tone LINE";
+	default:		return snd_djm_get_label_cap_common(wvalue);
+	}
+};
+
+static const char *snd_djm_get_label_caplevel(u8 device_idx, u16 wvalue)
+{
+	switch (device_idx) {
+	case SND_DJM_A9_IDX:		return snd_djm_get_label_caplevel_high(wvalue);
+	case SND_DJM_V10_IDX:		return snd_djm_get_label_caplevel_high(wvalue);
+	default:			return snd_djm_get_label_caplevel_common(wvalue);
+	}
+};
+
+static const char *snd_djm_get_label_cap(u8 device_idx, u16 wvalue)
+{
+	switch (device_idx) {
+	case SND_DJM_850_IDX:		return snd_djm_get_label_cap_850(wvalue);
+	default:			return snd_djm_get_label_cap_common(wvalue);
+	}
+};
+
+static const char *snd_djm_get_label_pb(u16 wvalue)
+{
+	switch (wvalue & 0x00ff) {
+	case SND_DJM_PB_CH1:	return "Ch1";
+	case SND_DJM_PB_CH2:	return "Ch2";
+	case SND_DJM_PB_AUX:	return "Aux";
+	default:		return NULL;
+	}
+};
+
+static const char *snd_djm_get_label(u8 device_idx, u16 wvalue, u16 windex)
+{
+	switch (windex) {
+	case SND_DJM_WINDEX_CAPLVL:	return snd_djm_get_label_caplevel(device_idx, wvalue);
+	case SND_DJM_WINDEX_CAP:	return snd_djm_get_label_cap(device_idx, wvalue);
+	case SND_DJM_WINDEX_PB:		return snd_djm_get_label_pb(wvalue);
+	default:			return NULL;
+	}
+};
+
+// common DJM capture level option values
+static const u16 snd_djm_opts_cap_level[] = {
+	0x0000, 0x0100, 0x0200, 0x0300 };
+
+// DJM-250MK2
+static const u16 snd_djm_opts_250mk2_cap1[] = {
+	0x0103, 0x0100, 0x0106, 0x0107, 0x0108, 0x0109, 0x010d, 0x010a };
+
+static const u16 snd_djm_opts_250mk2_cap2[] = {
+	0x0203, 0x0200, 0x0206, 0x0207, 0x0208, 0x0209, 0x020d, 0x020a };
+
+static const u16 snd_djm_opts_250mk2_cap3[] = {
+	0x030a, 0x0311, 0x0312, 0x0307, 0x0308, 0x0309, 0x030d };
+
+static const u16 snd_djm_opts_250mk2_pb1[] = { 0x0100, 0x0101, 0x0104 };
+static const u16 snd_djm_opts_250mk2_pb2[] = { 0x0200, 0x0201, 0x0204 };
+static const u16 snd_djm_opts_250mk2_pb3[] = { 0x0300, 0x0301, 0x0304 };
+
+static const struct snd_djm_ctl snd_djm_ctls_250mk2[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Input 1 Capture Switch",  250mk2_cap1, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch",  250mk2_cap2, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch",  250mk2_cap3, 0, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Output 1 Playback Switch", 250mk2_pb1, 0, SND_DJM_WINDEX_PB),
+	SND_DJM_CTL("Output 2 Playback Switch", 250mk2_pb2, 1, SND_DJM_WINDEX_PB),
+	SND_DJM_CTL("Output 3 Playback Switch", 250mk2_pb3, 2, SND_DJM_WINDEX_PB)
+};
+
+// DJM-450
+static const u16 snd_djm_opts_450_cap1[] = {
+	0x0103, 0x0100, 0x0106, 0x0107, 0x0108, 0x0109, 0x010d, 0x010a };
+
+static const u16 snd_djm_opts_450_cap2[] = {
+	0x0203, 0x0200, 0x0206, 0x0207, 0x0208, 0x0209, 0x020d, 0x020a };
+
+static const u16 snd_djm_opts_450_cap3[] = {
+	0x030a, 0x0311, 0x0312, 0x0307, 0x0308, 0x0309, 0x030d };
+
+static const u16 snd_djm_opts_450_pb1[] = { 0x0100, 0x0101, 0x0104 };
+static const u16 snd_djm_opts_450_pb2[] = { 0x0200, 0x0201, 0x0204 };
+static const u16 snd_djm_opts_450_pb3[] = { 0x0300, 0x0301, 0x0304 };
+
+static const struct snd_djm_ctl snd_djm_ctls_450[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Input 1 Capture Switch",  450_cap1, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch",  450_cap2, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch",  450_cap3, 0, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Output 1 Playback Switch", 450_pb1, 0, SND_DJM_WINDEX_PB),
+	SND_DJM_CTL("Output 2 Playback Switch", 450_pb2, 1, SND_DJM_WINDEX_PB),
+	SND_DJM_CTL("Output 3 Playback Switch", 450_pb3, 2, SND_DJM_WINDEX_PB)
+};
+
+// DJM-750
+static const u16 snd_djm_opts_750_cap1[] = {
+	0x0101, 0x0103, 0x0106, 0x0107, 0x0108, 0x0109, 0x010a, 0x010f };
+static const u16 snd_djm_opts_750_cap2[] = {
+	0x0200, 0x0201, 0x0206, 0x0207, 0x0208, 0x0209, 0x020a, 0x020f };
+static const u16 snd_djm_opts_750_cap3[] = {
+	0x0300, 0x0301, 0x0306, 0x0307, 0x0308, 0x0309, 0x030a, 0x030f };
+static const u16 snd_djm_opts_750_cap4[] = {
+	0x0401, 0x0403, 0x0406, 0x0407, 0x0408, 0x0409, 0x040a, 0x040f };
+
+static const struct snd_djm_ctl snd_djm_ctls_750[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Input 1 Capture Switch", 750_cap1, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch", 750_cap2, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch", 750_cap3, 0, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 4 Capture Switch", 750_cap4, 0, SND_DJM_WINDEX_CAP)
+};
+
+// DJM-850
+static const u16 snd_djm_opts_850_cap1[] = {
+	0x0100, 0x0103, 0x0106, 0x0107, 0x0108, 0x0109, 0x010a, 0x010f };
+static const u16 snd_djm_opts_850_cap2[] = {
+	0x0200, 0x0201, 0x0206, 0x0207, 0x0208, 0x0209, 0x020a, 0x020f };
+static const u16 snd_djm_opts_850_cap3[] = {
+	0x0300, 0x0301, 0x0306, 0x0307, 0x0308, 0x0309, 0x030a, 0x030f };
+static const u16 snd_djm_opts_850_cap4[] = {
+	0x0400, 0x0403, 0x0406, 0x0407, 0x0408, 0x0409, 0x040a, 0x040f };
+
+static const struct snd_djm_ctl snd_djm_ctls_850[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Input 1 Capture Switch", 850_cap1, 1, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch", 850_cap2, 0, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch", 850_cap3, 0, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 4 Capture Switch", 850_cap4, 1, SND_DJM_WINDEX_CAP)
+};
+
+// DJM-900NXS2
+static const u16 snd_djm_opts_900nxs2_cap1[] = {
+	0x0100, 0x0102, 0x0103, 0x0106, 0x0107, 0x0108, 0x0109, 0x010a };
+static const u16 snd_djm_opts_900nxs2_cap2[] = {
+	0x0200, 0x0202, 0x0203, 0x0206, 0x0207, 0x0208, 0x0209, 0x020a };
+static const u16 snd_djm_opts_900nxs2_cap3[] = {
+	0x0300, 0x0302, 0x0303, 0x0306, 0x0307, 0x0308, 0x0309, 0x030a };
+static const u16 snd_djm_opts_900nxs2_cap4[] = {
+	0x0400, 0x0402, 0x0403, 0x0406, 0x0407, 0x0408, 0x0409, 0x040a };
+static const u16 snd_djm_opts_900nxs2_cap5[] = {
+	0x0507, 0x0508, 0x0509, 0x050a, 0x0511, 0x0512, 0x0513, 0x0514 };
+
+static const struct snd_djm_ctl snd_djm_ctls_900nxs2[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Input 1 Capture Switch", 900nxs2_cap1, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch", 900nxs2_cap2, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch", 900nxs2_cap3, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 4 Capture Switch", 900nxs2_cap4, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 5 Capture Switch", 900nxs2_cap5, 3, SND_DJM_WINDEX_CAP)
+};
+
+// DJM-750MK2
+static const u16 snd_djm_opts_750mk2_cap1[] = {
+	0x0100, 0x0102, 0x0103, 0x0106, 0x0107, 0x0108, 0x0109, 0x010a };
+static const u16 snd_djm_opts_750mk2_cap2[] = {
+	0x0200, 0x0202, 0x0203, 0x0206, 0x0207, 0x0208, 0x0209, 0x020a };
+static const u16 snd_djm_opts_750mk2_cap3[] = {
+	0x0300, 0x0302, 0x0303, 0x0306, 0x0307, 0x0308, 0x0309, 0x030a };
+static const u16 snd_djm_opts_750mk2_cap4[] = {
+	0x0400, 0x0402, 0x0403, 0x0406, 0x0407, 0x0408, 0x0409, 0x040a };
+static const u16 snd_djm_opts_750mk2_cap5[] = {
+	0x0507, 0x0508, 0x0509, 0x050a, 0x0511, 0x0512, 0x0513, 0x0514 };
+
+static const u16 snd_djm_opts_750mk2_pb1[] = { 0x0100, 0x0101, 0x0104 };
+static const u16 snd_djm_opts_750mk2_pb2[] = { 0x0200, 0x0201, 0x0204 };
+static const u16 snd_djm_opts_750mk2_pb3[] = { 0x0300, 0x0301, 0x0304 };
+
+static const struct snd_djm_ctl snd_djm_ctls_750mk2[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Input 1 Capture Switch",   750mk2_cap1, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch",   750mk2_cap2, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch",   750mk2_cap3, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 4 Capture Switch",   750mk2_cap4, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 5 Capture Switch",   750mk2_cap5, 3, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Output 1 Playback Switch", 750mk2_pb1, 0, SND_DJM_WINDEX_PB),
+	SND_DJM_CTL("Output 2 Playback Switch", 750mk2_pb2, 1, SND_DJM_WINDEX_PB),
+	SND_DJM_CTL("Output 3 Playback Switch", 750mk2_pb3, 2, SND_DJM_WINDEX_PB)
+};
+
+// DJM-A9
+static const u16 snd_djm_opts_a9_cap_level[] = {
+	0x0000, 0x0100, 0x0200, 0x0300, 0x0400, 0x0500 };
+static const u16 snd_djm_opts_a9_cap1[] = {
+	0x0107, 0x0108, 0x0109, 0x010a, 0x010e,
+	0x111, 0x112, 0x113, 0x114, 0x0131, 0x132, 0x133, 0x134 };
+static const u16 snd_djm_opts_a9_cap2[] = {
+	0x0201, 0x0202, 0x0203, 0x0205, 0x0206, 0x0207, 0x0208, 0x0209, 0x020a, 0x020e };
+static const u16 snd_djm_opts_a9_cap3[] = {
+	0x0301, 0x0302, 0x0303, 0x0305, 0x0306, 0x0307, 0x0308, 0x0309, 0x030a, 0x030e };
+static const u16 snd_djm_opts_a9_cap4[] = {
+	0x0401, 0x0402, 0x0403, 0x0405, 0x0406, 0x0407, 0x0408, 0x0409, 0x040a, 0x040e };
+static const u16 snd_djm_opts_a9_cap5[] = {
+	0x0501, 0x0502, 0x0503, 0x0505, 0x0506, 0x0507, 0x0508, 0x0509, 0x050a, 0x050e };
+
+static const struct snd_djm_ctl snd_djm_ctls_a9[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", a9_cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Master Input Capture Switch", a9_cap1, 3, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 1 Capture Switch",  a9_cap2, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch",  a9_cap3, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch",  a9_cap4, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 4 Capture Switch",  a9_cap5, 2, SND_DJM_WINDEX_CAP)
+};
+
+// DJM-V10
+static const u16 snd_djm_opts_v10_cap_level[] = {
+	0x0000, 0x0100, 0x0200, 0x0300, 0x0400, 0x0500
+};
+
+static const u16 snd_djm_opts_v10_cap1[] = {
+	0x0103,
+	0x0100, 0x0102, 0x0106, 0x0110, 0x0107,
+	0x0108, 0x0109, 0x010a, 0x0121, 0x0122
+};
+
+static const u16 snd_djm_opts_v10_cap2[] = {
+	0x0200, 0x0202, 0x0206, 0x0210, 0x0207,
+	0x0208, 0x0209, 0x020a, 0x0221, 0x0222
+};
+
+static const u16 snd_djm_opts_v10_cap3[] = {
+	0x0303,
+	0x0300, 0x0302, 0x0306, 0x0310, 0x0307,
+	0x0308, 0x0309, 0x030a, 0x0321, 0x0322
+};
+
+static const u16 snd_djm_opts_v10_cap4[] = {
+	0x0403,
+	0x0400, 0x0402, 0x0406, 0x0410, 0x0407,
+	0x0408, 0x0409, 0x040a, 0x0421, 0x0422
+};
+
+static const u16 snd_djm_opts_v10_cap5[] = {
+	0x0500, 0x0502, 0x0506, 0x0510, 0x0507,
+	0x0508, 0x0509, 0x050a, 0x0521, 0x0522
+};
+
+static const u16 snd_djm_opts_v10_cap6[] = {
+	0x0603,
+	0x0600, 0x0602, 0x0606, 0x0610, 0x0607,
+	0x0608, 0x0609, 0x060a, 0x0621, 0x0622
+};
+
+static const struct snd_djm_ctl snd_djm_ctls_v10[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", v10_cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Input 1 Capture Switch", v10_cap1, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch", v10_cap2, 2, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch", v10_cap3, 0, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 4 Capture Switch", v10_cap4, 0, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 5 Capture Switch", v10_cap5, 0, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 6 Capture Switch", v10_cap6, 0, SND_DJM_WINDEX_CAP)
+	// playback channels are fixed and controlled by hardware knobs on the mixer
+};
+
+// DJM-S11
+static const u16 snd_djm_opts_s11_cap1[] = {
+	0x0100, 0x0103, 0x0106, 0x0107, 0x0108, 0x0109, 0x010d };
+static const u16 snd_djm_opts_s11_cap2[] = {
+	0x0200, 0x0203, 0x0206, 0x0207, 0x0208, 0x0209, 0x020d };
+static const u16 snd_djm_opts_s11_cap3[] = {
+	0x0307, 0x0308, 0x0309, 0x030a, 0x030d, 0x0311, 0x0312 };
+
+static const struct snd_djm_ctl snd_djm_ctls_s11[] = {
+	SND_DJM_CTL("Master Input Level Capture Switch", cap_level, 0, SND_DJM_WINDEX_CAPLVL),
+	SND_DJM_CTL("Input 1 Capture Switch", s11_cap1, 1, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 2 Capture Switch", s11_cap2, 1, SND_DJM_WINDEX_CAP),
+	SND_DJM_CTL("Input 3 Capture Switch", s11_cap3, 3, SND_DJM_WINDEX_CAP)
+};
+
+static const struct snd_djm_device snd_djm_devices[] = {
+	[SND_DJM_250MK2_IDX] = SND_DJM_DEVICE(250mk2),
+	[SND_DJM_750_IDX] = SND_DJM_DEVICE(750),
+	[SND_DJM_850_IDX] = SND_DJM_DEVICE(850),
+	[SND_DJM_900NXS2_IDX] = SND_DJM_DEVICE(900nxs2),
+	[SND_DJM_750MK2_IDX] = SND_DJM_DEVICE(750mk2),
+	[SND_DJM_450_IDX] = SND_DJM_DEVICE(450),
+	[SND_DJM_A9_IDX] = SND_DJM_DEVICE(a9),
+	[SND_DJM_V10_IDX] = SND_DJM_DEVICE(v10),
+	[SND_DJM_S11_IDX] = SND_DJM_DEVICE(s11),
+};
+
+static int snd_djm_controls_info(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_info *info)
+{
+	unsigned long private_value = kctl->private_value;
+	u8 device_idx = (private_value & SND_DJM_DEVICE_MASK) >> SND_DJM_DEVICE_SHIFT;
+	u8 ctl_idx = (private_value & SND_DJM_GROUP_MASK) >> SND_DJM_GROUP_SHIFT;
+	const struct snd_djm_device *device = &snd_djm_devices[device_idx];
+	const char *name;
+	const struct snd_djm_ctl *ctl;
+	size_t noptions;
+
+	if (ctl_idx >= device->ncontrols)
+		return -EINVAL;
+
+	ctl = &device->controls[ctl_idx];
+	noptions = ctl->noptions;
+	if (info->value.enumerated.item >= noptions)
+		info->value.enumerated.item = noptions - 1;
+
+	name = snd_djm_get_label(device_idx,
+				 ctl->options[info->value.enumerated.item],
+				 ctl->wIndex);
+	if (!name)
+		return -EINVAL;
+
+	strscpy(info->value.enumerated.name, name, sizeof(info->value.enumerated.name));
+	info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
+	info->count = 1;
+	info->value.enumerated.items = noptions;
+	return 0;
+}
+
+static int snd_djm_controls_update(struct usb_mixer_interface *mixer,
+				   u8 device_idx, u8 group, u16 value)
+{
+	const struct snd_djm_device *device = &snd_djm_devices[device_idx];
+
+	if (group >= device->ncontrols || value >= device->controls[group].noptions)
+		return -EINVAL;
+
+	CLASS(snd_usb_lock, pm)(mixer->chip);
+	if (pm.err)
+		return pm.err;
+
+	return snd_usb_ctl_msg(mixer->chip->dev,
+			       usb_sndctrlpipe(mixer->chip->dev, 0),
+			       USB_REQ_SET_FEATURE,
+			       USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			       device->controls[group].options[value],
+			       device->controls[group].wIndex,
+			       NULL, 0);
+}
+
+static int snd_djm_controls_get(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *elem)
+{
+	elem->value.enumerated.item[0] = kctl->private_value & SND_DJM_VALUE_MASK;
+	return 0;
+}
+
+static int snd_djm_controls_put(struct snd_kcontrol *kctl, struct snd_ctl_elem_value *elem)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+	unsigned long private_value = kctl->private_value;
+
+	u8 device = (private_value & SND_DJM_DEVICE_MASK) >> SND_DJM_DEVICE_SHIFT;
+	u8 group = (private_value & SND_DJM_GROUP_MASK) >> SND_DJM_GROUP_SHIFT;
+	u16 value = elem->value.enumerated.item[0];
+
+	kctl->private_value = (((unsigned long)device << SND_DJM_DEVICE_SHIFT) |
+			      (group << SND_DJM_GROUP_SHIFT) |
+			      value);
+
+	return snd_djm_controls_update(mixer, device, group, value);
+}
+
+static int snd_djm_controls_resume(struct usb_mixer_elem_list *list)
+{
+	unsigned long private_value = list->kctl->private_value;
+	u8 device = (private_value & SND_DJM_DEVICE_MASK) >> SND_DJM_DEVICE_SHIFT;
+	u8 group = (private_value & SND_DJM_GROUP_MASK) >> SND_DJM_GROUP_SHIFT;
+	u16 value = (private_value & SND_DJM_VALUE_MASK);
+
+	return snd_djm_controls_update(list->mixer, device, group, value);
+}
+
+static int snd_djm_controls_create(struct usb_mixer_interface *mixer,
+				   const u8 device_idx)
+{
+	int err, i;
+	u16 value;
+
+	const struct snd_djm_device *device = &snd_djm_devices[device_idx];
+
+	struct snd_kcontrol_new knew = {
+		.iface  = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+		.index = 0,
+		.info = snd_djm_controls_info,
+		.get  = snd_djm_controls_get,
+		.put  = snd_djm_controls_put
+	};
+
+	for (i = 0; i < device->ncontrols; i++) {
+		value = device->controls[i].default_value;
+		knew.name = device->controls[i].name;
+		knew.private_value =
+			((unsigned long)device_idx << SND_DJM_DEVICE_SHIFT) |
+			(i << SND_DJM_GROUP_SHIFT) |
+			value;
+		err = snd_djm_controls_update(mixer, device_idx, i, value);
+		if (err)
+			return err;
+		err = add_single_ctl_with_resume(mixer, 0, snd_djm_controls_resume,
+						 &knew, NULL);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
+{
+	int err = 0;
+
+	err = snd_usb_soundblaster_remote_init(mixer);
+	if (err < 0)
+		return err;
+
+	switch (mixer->chip->usb_id) {
+	/* Tascam US-16x08 */
+	case USB_ID(0x0644, 0x8047):
+		err = snd_us16x08_controls_create(mixer);
+		break;
+	case USB_ID(0x041e, 0x3020):
+	case USB_ID(0x041e, 0x3040):
+	case USB_ID(0x041e, 0x3042):
+	case USB_ID(0x041e, 0x30df):
+	case USB_ID(0x041e, 0x3048):
+		err = snd_audigy2nx_controls_create(mixer);
+		if (err < 0)
+			break;
+		snd_card_ro_proc_new(mixer->chip->card, "audigy2nx",
+				     mixer, snd_audigy2nx_proc_read);
+		break;
+
+	/* EMU0204 */
+	case USB_ID(0x041e, 0x3f19):
+		err = snd_emu0204_controls_create(mixer);
+		break;
+
+#if IS_REACHABLE(CONFIG_INPUT)
+	case USB_ID(0x054c, 0x0ce6): /* Sony DualSense controller (PS5) */
+	case USB_ID(0x054c, 0x0df2): /* Sony DualSense Edge controller (PS5) */
+		err = snd_dualsense_controls_create(mixer);
+		break;
+#endif /* IS_REACHABLE(CONFIG_INPUT) */
+
+	case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
+	case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C400 */
+		err = snd_c400_create_mixer(mixer);
+		break;
+
+	case USB_ID(0x0763, 0x2080): /* M-Audio Fast Track Ultra */
+	case USB_ID(0x0763, 0x2081): /* M-Audio Fast Track Ultra 8R */
+		err = snd_ftu_create_mixer(mixer);
+		break;
+
+	case USB_ID(0x0b05, 0x1739): /* ASUS Xonar U1 */
+	case USB_ID(0x0b05, 0x1743): /* ASUS Xonar U1 (2) */
+	case USB_ID(0x0b05, 0x17a0): /* ASUS Xonar U3 */
+		err = snd_xonar_u1_controls_create(mixer);
+		break;
+
+	case USB_ID(0x0d8c, 0x0103): /* Audio Advantage Micro II */
+		err = snd_microii_controls_create(mixer);
+		break;
+
+	case USB_ID(0x0dba, 0x1000): /* Digidesign Mbox 1 */
+		err = snd_mbox1_controls_create(mixer);
+		break;
+
+	case USB_ID(0x17cc, 0x1011): /* Traktor Audio 6 */
+		err = snd_nativeinstruments_create_mixer(/* checkpatch hack */
+				mixer,
+				snd_nativeinstruments_ta6_mixers,
+				ARRAY_SIZE(snd_nativeinstruments_ta6_mixers));
+		break;
+
+	case USB_ID(0x17cc, 0x1021): /* Traktor Audio 10 */
+		err = snd_nativeinstruments_create_mixer(/* checkpatch hack */
+				mixer,
+				snd_nativeinstruments_ta10_mixers,
+				ARRAY_SIZE(snd_nativeinstruments_ta10_mixers));
+		break;
+
+	case USB_ID(0x200c, 0x1018): /* Electrix Ebox-44 */
+		/* detection is disabled in mixer_maps.c */
+		err = snd_create_std_mono_table(mixer, ebox44_table);
+		break;
+
+	case USB_ID(0x1235, 0x8010): /* Focusrite Forte */
+		err = snd_forte_controls_create(mixer);
+		break;
+	case USB_ID(0x1235, 0x8012): /* Focusrite Scarlett 6i6 */
+	case USB_ID(0x1235, 0x8002): /* Focusrite Scarlett 8i6 */
+	case USB_ID(0x1235, 0x8004): /* Focusrite Scarlett 18i6 */
+	case USB_ID(0x1235, 0x8014): /* Focusrite Scarlett 18i8 */
+	case USB_ID(0x1235, 0x800c): /* Focusrite Scarlett 18i20 */
+		err = snd_scarlett_controls_create(mixer);
+		break;
+
+	case USB_ID(0x1235, 0x8203): /* Focusrite Scarlett 6i6 2nd Gen */
+	case USB_ID(0x1235, 0x8204): /* Focusrite Scarlett 18i8 2nd Gen */
+	case USB_ID(0x1235, 0x8201): /* Focusrite Scarlett 18i20 2nd Gen */
+	case USB_ID(0x1235, 0x8211): /* Focusrite Scarlett Solo 3rd Gen */
+	case USB_ID(0x1235, 0x8210): /* Focusrite Scarlett 2i2 3rd Gen */
+	case USB_ID(0x1235, 0x8212): /* Focusrite Scarlett 4i4 3rd Gen */
+	case USB_ID(0x1235, 0x8213): /* Focusrite Scarlett 8i6 3rd Gen */
+	case USB_ID(0x1235, 0x8214): /* Focusrite Scarlett 18i8 3rd Gen */
+	case USB_ID(0x1235, 0x8215): /* Focusrite Scarlett 18i20 3rd Gen */
+	case USB_ID(0x1235, 0x8216): /* Focusrite Vocaster One */
+	case USB_ID(0x1235, 0x8217): /* Focusrite Vocaster Two */
+	case USB_ID(0x1235, 0x8218): /* Focusrite Scarlett Solo 4th Gen */
+	case USB_ID(0x1235, 0x8219): /* Focusrite Scarlett 2i2 4th Gen */
+	case USB_ID(0x1235, 0x821a): /* Focusrite Scarlett 4i4 4th Gen */
+	case USB_ID(0x1235, 0x8206): /* Focusrite Clarett 2Pre USB */
+	case USB_ID(0x1235, 0x8207): /* Focusrite Clarett 4Pre USB */
+	case USB_ID(0x1235, 0x8208): /* Focusrite Clarett 8Pre USB */
+	case USB_ID(0x1235, 0x820a): /* Focusrite Clarett+ 2Pre */
+	case USB_ID(0x1235, 0x820b): /* Focusrite Clarett+ 4Pre */
+	case USB_ID(0x1235, 0x820c): /* Focusrite Clarett+ 8Pre */
+		err = snd_scarlett2_init(mixer);
+		break;
+
+	case USB_ID(0x1235, 0x821b): /* Focusrite Scarlett 16i16 4th Gen */
+	case USB_ID(0x1235, 0x821c): /* Focusrite Scarlett 18i16 4th Gen */
+	case USB_ID(0x1235, 0x821d): /* Focusrite Scarlett 18i20 4th Gen */
+	case USB_ID(0x1235, 0x821e): /* Focusrite ISA C8X */
+		err = snd_fcp_init(mixer);
+		break;
+
+	case USB_ID(0x041e, 0x323b): /* Creative Sound Blaster E1 */
+		err = snd_soundblaster_e1_switch_create(mixer);
+		break;
+	case USB_ID(0x0bda, 0x4014): /* Dell WD15 dock */
+		err = dell_dock_mixer_create(mixer);
+		if (err < 0)
+			break;
+		err = dell_dock_mixer_init(mixer);
+		break;
+	case USB_ID(0x0bda, 0x402e): /* Dell WD19 dock */
+		err = dell_dock_mixer_create(mixer);
+		break;
+
+	case USB_ID(0x2a39, 0x3fd2): /* RME ADI-2 Pro */
+	case USB_ID(0x2a39, 0x3fd3): /* RME ADI-2 DAC */
+	case USB_ID(0x2a39, 0x3fd4): /* RME */
+		err = snd_rme_controls_create(mixer);
+		break;
+
+	case USB_ID(0x194f, 0x010c): /* Presonus Studio 1810c */
+		err = snd_sc1810_init_mixer(mixer);
+		break;
+	case USB_ID(0x194f, 0x010d): /* Presonus Studio 1824c */
+		err = snd_sc1810_init_mixer(mixer);
+		break;
+	case USB_ID(0x194f, 0x0107): /* Presonus Studio 1824 */
+		err = snd_sc1810_init_mixer(mixer);
+		break;
+	case USB_ID(0x2a39, 0x3fb0): /* RME Babyface Pro FS */
+		err = snd_bbfpro_controls_create(mixer);
+		break;
+	case USB_ID(0x2a39, 0x3f8c): /* RME Digiface USB */
+	case USB_ID(0x2a39, 0x3fa0): /* RME Digiface USB (alternate) */
+		err = snd_rme_digiface_controls_create(mixer);
+		break;
+	case USB_ID(0x2b73, 0x0017): /* Pioneer DJ DJM-250MK2 */
+		err = snd_djm_controls_create(mixer, SND_DJM_250MK2_IDX);
+		break;
+	case USB_ID(0x2b73, 0x0013): /* Pioneer DJ DJM-450 */
+		err = snd_djm_controls_create(mixer, SND_DJM_450_IDX);
+		break;
+	case USB_ID(0x08e4, 0x017f): /* Pioneer DJ DJM-750 */
+		err = snd_djm_controls_create(mixer, SND_DJM_750_IDX);
+		break;
+	case USB_ID(0x2b73, 0x001b): /* Pioneer DJ DJM-750MK2 */
+		err = snd_djm_controls_create(mixer, SND_DJM_750MK2_IDX);
+		break;
+	case USB_ID(0x08e4, 0x0163): /* Pioneer DJ DJM-850 */
+		err = snd_djm_controls_create(mixer, SND_DJM_850_IDX);
+		break;
+	case USB_ID(0x2b73, 0x000a): /* Pioneer DJ DJM-900NXS2 */
+		err = snd_djm_controls_create(mixer, SND_DJM_900NXS2_IDX);
+		break;
+	case USB_ID(0x2b73, 0x003c): /* Pioneer DJ / AlphaTheta DJM-A9 */
+		err = snd_djm_controls_create(mixer, SND_DJM_A9_IDX);
+		break;
+	case USB_ID(0x2b73, 0x0034): /* Pioneer DJ DJM-V10 */
+		err = snd_djm_controls_create(mixer, SND_DJM_V10_IDX);
+		break;
+	case USB_ID(0x2b73, 0x0037): /* Pioneer DJ DJM-S11 */
+		err = snd_djm_controls_create(mixer, SND_DJM_S11_IDX);
+		break;
+	case USB_ID(0x03f0, 0x0269): /* HP TB Dock G2 */
+		err = hp_dock_mixer_create(mixer);
+		break;
+	}
+
+	return err;
+}
+
+void snd_usb_mixer_resume_quirk(struct usb_mixer_interface *mixer)
+{
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x0bda, 0x4014): /* Dell WD15 dock */
+		dell_dock_mixer_init(mixer);
+		break;
+	}
+}
+
+void snd_usb_mixer_rc_memory_change(struct usb_mixer_interface *mixer,
+				    int unitid)
+{
+	if (!mixer->rc_cfg)
+		return;
+	/* unit ids specific to Extigy/Audigy 2 NX: */
+	switch (unitid) {
+	case 0: /* remote control */
+		mixer->rc_urb->dev = mixer->chip->dev;
+		usb_submit_urb(mixer->rc_urb, GFP_ATOMIC);
+		break;
+	case 4: /* digital in jack */
+	case 7: /* line in jacks */
+	case 19: /* speaker out jacks */
+	case 20: /* headphones out jack */
+		break;
+	/* live24ext: 4 = line-in jack */
+	case 3:	/* hp-out jack (may actuate Mute) */
+		if (mixer->chip->usb_id == USB_ID(0x041e, 0x3040) ||
+		    mixer->chip->usb_id == USB_ID(0x041e, 0x3048))
+			snd_usb_mixer_notify_id(mixer, mixer->rc_cfg->mute_mixer_id);
+		break;
+	default:
+		usb_audio_dbg(mixer->chip, "memory change in unknown unit %d\n", unitid);
+		break;
+	}
+}
+
+static void snd_dragonfly_quirk_db_scale(struct usb_mixer_interface *mixer,
+					 struct usb_mixer_elem_info *cval,
+					 struct snd_kcontrol *kctl)
+{
+	/* Approximation using 10 ranges based on output measurement on hw v1.2.
+	 * This seems close to the cubic mapping e.g. alsamixer uses.
+	 */
+	static const DECLARE_TLV_DB_RANGE(scale,
+		 0,  1, TLV_DB_MINMAX_ITEM(-5300, -4970),
+		 2,  5, TLV_DB_MINMAX_ITEM(-4710, -4160),
+		 6,  7, TLV_DB_MINMAX_ITEM(-3884, -3710),
+		 8, 14, TLV_DB_MINMAX_ITEM(-3443, -2560),
+		15, 16, TLV_DB_MINMAX_ITEM(-2475, -2324),
+		17, 19, TLV_DB_MINMAX_ITEM(-2228, -2031),
+		20, 26, TLV_DB_MINMAX_ITEM(-1910, -1393),
+		27, 31, TLV_DB_MINMAX_ITEM(-1322, -1032),
+		32, 40, TLV_DB_MINMAX_ITEM(-968, -490),
+		41, 50, TLV_DB_MINMAX_ITEM(-441, 0),
+	);
+
+	if (cval->min == 0 && cval->max == 50) {
+		usb_audio_info(mixer->chip, "applying DragonFly dB scale quirk (0-50 variant)\n");
+		kctl->tlv.p = scale;
+		kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
+		kctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+
+	} else if (cval->min == 0 && cval->max <= 1000) {
+		/* Some other clearly broken DragonFly variant.
+		 * At least a 0..53 variant (hw v1.0) exists.
+		 */
+		usb_audio_info(mixer->chip, "ignoring too narrow dB range on a DragonFly device");
+		kctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+	}
+}
+
+static void snd_usb_mv_silicon_quirks(struct usb_mixer_interface *mixer,
+				      struct usb_mixer_elem_info *cval,
+				      struct snd_kcontrol *kctl)
+{
+	if (cval->min == 0 && cval->max == 4096 && cval->res == 1) {
+		/* The final effects will be printed later. */
+		usb_audio_info(mixer->chip, "applying MV-SILICON quirks (0/4096/1 variant)\n");
+
+		/* Respect MIN_MUTE set by module parameters. */
+		if (!(mixer->chip->quirk_flags & QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE))
+			mixer->chip->quirk_flags |= QUIRK_FLAG_MIXER_PLAYBACK_LINEAR_VOL;
+		if (!(mixer->chip->quirk_flags & QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE))
+			mixer->chip->quirk_flags |= QUIRK_FLAG_MIXER_CAPTURE_LINEAR_VOL;
+	} else {
+		usb_audio_dbg(mixer->chip, "not applying MV-SILICON quirks on unknown variant");
+	}
+}
+
+/*
+ * Some Plantronics headsets have control names that don't meet ALSA naming
+ * standards. This function fixes nonstandard source names. By the time
+ * this function is called the control name should look like one of these:
+ * "source names Playback Volume"
+ * "source names Playback Switch"
+ * "source names Capture Volume"
+ * "source names Capture Switch"
+ * If any of the trigger words are found in the name then the name will
+ * be changed to:
+ * "Headset Playback Volume"
+ * "Headset Playback Switch"
+ * "Headset Capture Volume"
+ * "Headset Capture Switch"
+ * depending on the current suffix.
+ */
+static void snd_fix_plt_name(struct snd_usb_audio *chip,
+			     struct snd_ctl_elem_id *id)
+{
+	/* no variant of "Sidetone" should be added to this list */
+	static const char * const trigger[] = {
+		"Earphone", "Microphone", "Receive", "Transmit"
+	};
+	static const char * const suffix[] = {
+		" Playback Volume", " Playback Switch",
+		" Capture Volume", " Capture Switch"
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(trigger); i++)
+		if (strstr(id->name, trigger[i]))
+			goto triggered;
+	usb_audio_dbg(chip, "no change in %s\n", id->name);
+	return;
+
+triggered:
+	for (i = 0; i < ARRAY_SIZE(suffix); i++)
+		if (strstr(id->name, suffix[i])) {
+			usb_audio_dbg(chip, "fixing kctl name %s\n", id->name);
+			snprintf(id->name, sizeof(id->name), "Headset%s",
+				 suffix[i]);
+			return;
+		}
+	usb_audio_dbg(chip, "something wrong in kctl name %s\n", id->name);
+}
+
+static void snd_usb_mixer_fu_quirk_linear_scale(struct usb_mixer_interface *mixer,
+						struct usb_mixer_elem_info *cval,
+						struct snd_kcontrol *kctl)
+{
+	static const DECLARE_TLV_DB_LINEAR(scale, TLV_DB_GAIN_MUTE, 0);
+
+	if (cval->min_mute) {
+		/*
+		 * We are clearing SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK,
+		 * resulting in min_mute being a no-op.
+		 */
+		usb_audio_warn(mixer->chip, "LINEAR_VOL overrides MIN_MUTE\n");
+	}
+
+	kctl->tlv.p = scale;
+	kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
+	kctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+}
+
+void snd_usb_mixer_fu_apply_quirk(struct usb_mixer_interface *mixer,
+				  struct usb_mixer_elem_info *cval, int unitid,
+				  struct snd_kcontrol *kctl)
+{
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x21b4, 0x0081): /* AudioQuest DragonFly */
+		if (unitid == 7 && cval->control == UAC_FU_VOLUME)
+			snd_dragonfly_quirk_db_scale(mixer, cval, kctl);
+		break;
+	}
+
+	if (cval->control == UAC_FU_VOLUME &&
+	    !strncmp(mixer->chip->card->longname, "MV-SILICON", 10))
+		snd_usb_mv_silicon_quirks(mixer, cval, kctl);
+
+	/* lowest playback value is muted on some devices */
+	if (mixer->chip->quirk_flags & QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE)
+		if (strstr(kctl->id.name, "Playback")) {
+			usb_audio_info(mixer->chip,
+				       "applying playback min mute quirk\n");
+			cval->min_mute = 1;
+		}
+
+	/* lowest capture value is muted on some devices */
+	if (mixer->chip->quirk_flags & QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE)
+		if (strstr(kctl->id.name, "Capture")) {
+			usb_audio_info(mixer->chip,
+				       "applying capture min mute quirk\n");
+			cval->min_mute = 1;
+		}
+
+	if (mixer->chip->quirk_flags & QUIRK_FLAG_MIXER_PLAYBACK_LINEAR_VOL)
+		if (cval->control == UAC_FU_VOLUME && strstr(kctl->id.name, "Playback")) {
+			usb_audio_info(mixer->chip,
+				       "applying playback linear volume quirk\n");
+			snd_usb_mixer_fu_quirk_linear_scale(mixer, cval, kctl);
+		}
+
+	if (mixer->chip->quirk_flags & QUIRK_FLAG_MIXER_CAPTURE_LINEAR_VOL)
+		if (cval->control == UAC_FU_VOLUME && strstr(kctl->id.name, "Capture")) {
+			usb_audio_info(mixer->chip,
+				       "applying capture linear volume quirk\n");
+			snd_usb_mixer_fu_quirk_linear_scale(mixer, cval, kctl);
+		}
+
+	/* ALSA-ify some Plantronics headset control names */
+	if (USB_ID_VENDOR(mixer->chip->usb_id) == 0x047f &&
+	    (cval->control == UAC_FU_MUTE || cval->control == UAC_FU_VOLUME))
+		snd_fix_plt_name(mixer->chip, &kctl->id);
+}
diff --git a/sound/usb/mixer_quirks.h b/sound/usb/mixer_quirks.h
new file mode 100644
index 000000000..4ba01ba3f
--- /dev/null
+++ b/sound/usb/mixer_quirks.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef SND_USB_MIXER_QUIRKS_H
+#define SND_USB_MIXER_QUIRKS_H
+
+int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer);
+
+void snd_emuusb_set_samplerate(struct snd_usb_audio *chip,
+			       unsigned char samplerate_id);
+
+void snd_usb_mixer_rc_memory_change(struct usb_mixer_interface *mixer,
+				    int unitid);
+
+void snd_usb_mixer_fu_apply_quirk(struct usb_mixer_interface *mixer,
+				  struct usb_mixer_elem_info *cval, int unitid,
+				  struct snd_kcontrol *kctl);
+
+void snd_usb_mixer_resume_quirk(struct usb_mixer_interface *mixer);
+
+#endif /* SND_USB_MIXER_QUIRKS_H */
+
diff --git a/sound/usb/mixer_s1810c.c b/sound/usb/mixer_s1810c.c
new file mode 100644
index 000000000..bdb5e3aaf
--- /dev/null
+++ b/sound/usb/mixer_s1810c.c
@@ -0,0 +1,707 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Presonus Studio 1810c driver for ALSA
+ * Copyright (C) 2019 Nick Kossifidis <mickflemm@gmail.com>
+ *
+ * Based on reverse engineering of the communication protocol
+ * between the windows driver / Univeral Control (UC) program
+ * and the device, through usbmon.
+ *
+ * For now this bypasses the mixer, with all channels split,
+ * so that the software can mix with greater flexibility.
+ * It also adds controls for the 4 buttons on the front of
+ * the device.
+ */
+
+#include <linux/usb.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <sound/control.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "mixer_quirks.h"
+#include "helper.h"
+#include "mixer_s1810c.h"
+
+/*
+ * DISCLAIMER: These are just guesses based on the
+ * dumps I got.
+ *
+ * It seems like a selects between
+ * device (0), mixer (0x64) and output (0x65)
+ *
+ * For mixer (0x64):
+ *  * b selects an input channel (see below).
+ *  * c selects an output channel pair (see below).
+ *  * d selects left (0) or right (1) of that pair.
+ *  * e level : see MIXER_LEVEL_* defines below.
+ *	Also used for setting volume levels
+ *	in which case b is also set so I guess
+ *	this way it is possible to set the volume
+ *	level from the specified input to the
+ *	specified output.
+ *
+ * IN Channels:
+ * 0  - 7  Mic/Inst/Line (Analog inputs)
+ * 8  - 9  S/PDIF
+ * 10 - 17 ADAT
+ * 18 - 35 DAW (Inputs from the host)
+ *
+ * OUT Channels (pairs):
+ * 0 -> Main out
+ * 1 -> Line1/2
+ * 2 -> Line3/4
+ * 3 -> S/PDIF
+ * 4 -> ADAT?
+ *
+ * For device (0):
+ *  * b and c are not used, at least not on the
+ *    dumps I got.
+ *  * d sets the control id to be modified
+ *    (see below).
+ *  * e sets the setting for that control.
+ *    (so for the switches I was interested
+ *    in it's 0/1)
+ *
+ * For output (0x65):
+ *   * b is the output channel (see above).
+ *   * c is zero.
+ *   * e I guess the same as with mixer
+ *
+ */
+/* struct s1810c_ctl_packet - basic vendor request
+ * @selector: device/mixer/output
+ * @b: request-dependant field b
+ * @tag: fixed value identifying type of request
+ * @len: sizeof this struct - 8 (excludes first 2 fields)
+ *	i.e. for basic struct s1810c_ctl_packet: len is 5*4=0x14
+ * @c: request-dependant field c
+ * @d: request-dependant field d
+ * @e: request-dependant field e
+ *
+ * See longer description above. This could be combined
+ * (as a union?) with the longer struct s1810c_state_packet
+ */
+struct s1810c_ctl_packet {
+	__le32 selector;
+	__le32 b;
+	__le32 tag;
+	__le32 len;
+	__le32 c;
+	__le32 d;
+	__le32 e;
+};
+
+/* selectors for CMD request
+ */
+#define SC1810C_SEL_DEVICE 0
+#define SC1810C_SEL_MIXER 0x64
+#define SC1810C_SEL_OUTPUT 0x65
+
+
+/* control ids */
+#define SC1810C_CTL_LINE_SW	0
+#define SC1810C_CTL_MUTE_SW	1
+#define SC1824C_CTL_MONO_SW	2
+#define SC1810C_CTL_AB_SW	3
+#define SC1810C_CTL_48V_SW	4
+
+/* USB Control (vendor) requests
+ */
+#define SC1810C_CMD_REQ	160
+#define SC1810C_CMD_REQTYPE \
+	(USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT)
+#define SC1810C_CMD_TAG		0x50617269
+#define SC1810C_CMD_LEN		0x14
+
+#define SC1810C_SET_STATE_REQ	161
+#define SC1810C_SET_STATE_REQTYPE SC1810C_CMD_REQTYPE
+#define SC1810C_SET_STATE_TAG	0x64656D73
+#define SC1810C_SET_STATE_LEN	0xF4
+
+#define SC1810C_GET_STATE_REQ	162
+#define SC1810C_GET_STATE_REQTYPE \
+	(USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN)
+#define SC1810C_GET_STATE_TAG	SC1810C_SET_STATE_TAG
+#define SC1810C_GET_STATE_LEN	SC1810C_SET_STATE_LEN
+
+/* Mixer levels normally range from 0 (off) to 0x0100 0000 (0 dB).
+ * raw_level = 2^24 * 10^(db_level / 20), thus
+ * -3dB = 0xb53bf0 (technically, half-power -3.01...dB would be 0xb504f3)
+ * -96dB = 0x109
+ * -99dB = 0xBC
+ * PC software sliders cover -96 to +10dB (0x0329 8b08),
+ * but the value 0 (-inf dB) can be used when e.g. Mixer Bypass is enabled.
+ * Unclear what the hardware's maximum value is.
+ *
+ * Note, when a channel is panned to two channels (stereo),
+ * the mixer level is set to slider value (by default -96dB) minus 3dB,
+ * which explains the -99dB value seen in USB captures.
+ */
+#define MIXER_LEVEL_MUTE 0
+#define MIXER_LEVEL_N99DB 0xbc
+#define MIXER_LEVEL_N3DB 0xb53bf0
+#define MIXER_LEVEL_0DB 0x1000000
+
+/*
+ * This packet includes mixer volumes and
+ * various other fields, it's an extended
+ * version of ctl_packet, with a and b
+ * being zero and different tag/length.
+ */
+struct s1810c_state_packet {
+	__le32 fields[63];
+};
+
+/* indices into s1810c_state_packet.fields[]
+ */
+#define SC1810C_STATE_TAG_IDX	2
+#define SC1810C_STATE_LEN_IDX	3
+
+#define SC1810C_STATE_48V_SW	58
+#define SC1810C_STATE_LINE_SW	59
+#define SC1810C_STATE_MUTE_SW	60
+#define SC1824C_STATE_MONO_SW	61
+#define SC1810C_STATE_AB_SW	62
+
+struct s1810_mixer_state {
+	uint16_t seqnum;
+	struct mutex usb_mutex;
+	struct mutex data_mutex;
+};
+
+static int
+snd_s1810c_send_ctl_packet(struct usb_device *dev, u32 sel,
+			   u32 b, u32 c, u32 d, u32 e)
+{
+	struct s1810c_ctl_packet pkt = { 0 };
+	int ret = 0;
+
+	pkt.tag = __cpu_to_le32(SC1810C_CMD_TAG);
+	pkt.len = __cpu_to_le32(SC1810C_CMD_LEN);
+
+	pkt.selector = __cpu_to_le32(sel);
+	pkt.b = __cpu_to_le32(b);
+	pkt.c = __cpu_to_le32(c);
+	pkt.d = __cpu_to_le32(d);
+	pkt.e = __cpu_to_le32(e);
+
+	ret = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			      SC1810C_CMD_REQ,
+			      SC1810C_CMD_REQTYPE, 0, 0, &pkt, sizeof(pkt));
+	if (ret < 0) {
+		dev_warn(&dev->dev, "could not send ctl packet\n");
+		return ret;
+	}
+	return 0;
+}
+
+/*
+ * When opening Universal Control the program periodically
+ * sends and receives state packets for syncinc state between
+ * the device and the host.
+ *
+ * Note that if we send only the request to get data back we'll
+ * get an error, we need to first send an empty state packet and
+ * then ask to receive a filled. Their seqnumbers must also match.
+ */
+static int
+snd_sc1810c_get_status_field(struct usb_device *dev,
+			     u32 *field, int field_idx, uint16_t *seqnum)
+{
+	struct s1810c_state_packet pkt_out = { { 0 } };
+	struct s1810c_state_packet pkt_in = { { 0 } };
+	int ret = 0;
+
+	pkt_out.fields[SC1810C_STATE_TAG_IDX] = __cpu_to_le32(SC1810C_SET_STATE_TAG);
+	pkt_out.fields[SC1810C_STATE_LEN_IDX] = __cpu_to_le32(SC1810C_SET_STATE_LEN);
+	ret = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			      SC1810C_SET_STATE_REQ,
+			      SC1810C_SET_STATE_REQTYPE,
+			      (*seqnum), 0, &pkt_out, sizeof(pkt_out));
+	if (ret < 0) {
+		dev_warn(&dev->dev, "could not send state packet (%d)\n", ret);
+		return ret;
+	}
+
+	ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      SC1810C_GET_STATE_REQ,
+			      SC1810C_GET_STATE_REQTYPE,
+			      (*seqnum), 0, &pkt_in, sizeof(pkt_in));
+	if (ret < 0) {
+		dev_warn(&dev->dev, "could not get state field %u (%d)\n",
+			 field_idx, ret);
+		return ret;
+	}
+
+	(*field) = __le32_to_cpu(pkt_in.fields[field_idx]);
+	(*seqnum)++;
+	return 0;
+}
+
+/*
+ * This is what I got when bypassing the mixer with
+ * all channels split. I'm not 100% sure of what's going
+ * on, I could probably clean this up based on my observations
+ * but I prefer to keep the same behavior as the windows driver.
+ */
+static int snd_s1810c_init_mixer_maps(struct snd_usb_audio *chip)
+{
+	u32 a, b, c, e, n, off, left, right;
+	struct usb_device *dev = chip->dev;
+
+	switch (chip->usb_id) {
+	case USB_ID(0x194f, 0x010c): /* 1810c */
+		/* Set initial volume levels ? */
+		a = SC1810C_SEL_MIXER;
+		e = MIXER_LEVEL_N99DB;
+		for (n = 0; n < 2; n++) {
+			off = n * 18;
+			for (b = off; b < 18 + off; b++) {
+				/* This channel to all outputs ? */
+				for (c = 0; c <= 8; c++) {
+					snd_s1810c_send_ctl_packet(dev, a, b, c, 0, e);
+					snd_s1810c_send_ctl_packet(dev, a, b, c, 1, e);
+				}
+				/* This channel to main output (again) */
+				snd_s1810c_send_ctl_packet(dev, a, b, 0, 0, e);
+				snd_s1810c_send_ctl_packet(dev, a, b, 0, 1, e);
+			}
+			/*
+			 * I noticed on UC that DAW channels have different
+			 * initial volumes, so this makes sense.
+			 */
+			e = MIXER_LEVEL_N3DB;
+		}
+
+		/* Connect analog outputs ? */
+		a = SC1810C_SEL_OUTPUT;
+		for (b = 1; b < 3; b++) {
+			snd_s1810c_send_ctl_packet(dev, a, b, 0, 0, MIXER_LEVEL_0DB);
+			snd_s1810c_send_ctl_packet(dev, a, b, 0, 1, MIXER_LEVEL_0DB);
+		}
+		snd_s1810c_send_ctl_packet(dev, a, 0, 0, 0, MIXER_LEVEL_0DB);
+		snd_s1810c_send_ctl_packet(dev, a, 0, 0, 1, MIXER_LEVEL_0DB);
+
+		/* Set initial volume levels for S/PDIF mappings ? */
+		a = SC1810C_SEL_MIXER;
+		e = MIXER_LEVEL_N99DB;
+		c = 3;
+		for (n = 0; n < 2; n++) {
+			off = n * 18;
+			for (b = off; b < 18 + off; b++) {
+				snd_s1810c_send_ctl_packet(dev, a, b, c, 0, e);
+				snd_s1810c_send_ctl_packet(dev, a, b, c, 1, e);
+			}
+			e = MIXER_LEVEL_N3DB;
+		}
+
+		/* Connect S/PDIF output ? */
+		a = SC1810C_SEL_OUTPUT;
+		snd_s1810c_send_ctl_packet(dev, a, 3, 0, 0, MIXER_LEVEL_0DB);
+		snd_s1810c_send_ctl_packet(dev, a, 3, 0, 1, MIXER_LEVEL_0DB);
+
+		/* Connect all outputs (again) ? */
+		a = SC1810C_SEL_OUTPUT;
+		for (b = 0; b < 4; b++) {
+			snd_s1810c_send_ctl_packet(dev, a, b, 0, 0, MIXER_LEVEL_0DB);
+			snd_s1810c_send_ctl_packet(dev, a, b, 0, 1, MIXER_LEVEL_0DB);
+		}
+
+		/* Basic routing to get sound out of the device */
+		a = SC1810C_SEL_MIXER;
+		for (c = 0; c < 4; c++) {
+			for (b = 0; b < 36; b++) {
+				if ((c == 0 && b == 18) ||	/* DAW1/2 -> Main */
+					(c == 1 && b == 20) ||	/* DAW3/4 -> Line3/4 */
+					(c == 2 && b == 22) ||	/* DAW4/5 -> Line5/6 */
+					(c == 3 && b == 24)) {	/* DAW5/6 -> S/PDIF */
+					/* Left */
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 0, MIXER_LEVEL_0DB);
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 1, MIXER_LEVEL_MUTE);
+					b++;
+					/* Right */
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 0, MIXER_LEVEL_MUTE);
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 1, MIXER_LEVEL_0DB);
+				} else {
+					/* Leave the rest disconnected */
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 0, MIXER_LEVEL_MUTE);
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 1, MIXER_LEVEL_MUTE);
+				}
+			}
+		}
+
+		/* Set initial volume levels for S/PDIF (again) ? */
+		a = SC1810C_SEL_MIXER;
+		e = MIXER_LEVEL_N99DB;
+		c = 3;
+		for (n = 0; n < 2; n++) {
+			off = n * 18;
+			for (b = off; b < 18 + off; b++) {
+				snd_s1810c_send_ctl_packet(dev, a, b, c, 0, e);
+				snd_s1810c_send_ctl_packet(dev, a, b, c, 1, e);
+			}
+			e = MIXER_LEVEL_N3DB;
+		}
+
+		/* Connect S/PDIF outputs (again) ? */
+		a = SC1810C_SEL_OUTPUT;
+		snd_s1810c_send_ctl_packet(dev, a, 3, 0, 0, MIXER_LEVEL_0DB);
+		snd_s1810c_send_ctl_packet(dev, a, 3, 0, 1, MIXER_LEVEL_0DB);
+
+		/* Again ? */
+		snd_s1810c_send_ctl_packet(dev, a, 3, 0, 0, MIXER_LEVEL_0DB);
+		snd_s1810c_send_ctl_packet(dev, a, 3, 0, 1, MIXER_LEVEL_0DB);
+		break;
+
+	case USB_ID(0x194f, 0x0107): /* 1824 */
+	case USB_ID(0x194f, 0x010d): /* 1824c */
+		/* Set all output faders to unity gain */
+		a = SC1810C_SEL_OUTPUT;
+		c = 0x00;
+		for (b = 0; b < 9; b++) {
+			snd_s1810c_send_ctl_packet(dev, a, b, c, 0, MIXER_LEVEL_0DB);
+			snd_s1810c_send_ctl_packet(dev, a, b, c, 1, MIXER_LEVEL_0DB);
+		}
+
+		/* Set
+		 * Daw 1 -> Line out 1 (left), Daw 2 -> Line out 2 (right)
+		 * Daw 3 -> Line out 3, (left) Daw 4 -> Line out 4 (right)
+		 * Daw 5 -> Line out 5, (left) Daw 6 -> Line out 6 (right)
+		 * Daw 7 -> Line out 7, (left) Daw 8 -> Line out 8 (right)
+		 * Daw 9 -> SPDIF out 1, (left) Daw 10 -> SPDIF out 2 (right)
+		 * Daw 11 -> ADAT out 1, (left) Daw 12 -> ADAT out 2 (right)
+		 * Daw 13 -> ADAT out 3, (left) Daw 14 -> ADAT out 4 (right)
+		 * Daw 15 -> ADAT out 5, (left) Daw 16 -> ADAT out 6 (right)
+		 * Daw 17 -> ADAT out 7, (left) Daw 18 -> ADAT out 8 (right)
+		 * Everything else muted
+		 */
+		a = SC1810C_SEL_MIXER;
+		/* The first Daw channel is channel 18 */
+		left = 18;
+
+		for (c = 0; c < 9; c++) {
+			right = left + 1;
+
+			for (b = 0; b < 36; b++) {
+				if (b == left) {
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 0, MIXER_LEVEL_0DB);
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 1, MIXER_LEVEL_MUTE);
+				} else if (b == right) {
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 0, MIXER_LEVEL_MUTE);
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 1, MIXER_LEVEL_0DB);
+				} else {
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 0, MIXER_LEVEL_MUTE);
+					snd_s1810c_send_ctl_packet(dev,
+							a, b, c, 1, MIXER_LEVEL_MUTE);
+				}
+			}
+			left += 2;
+		}
+		break;
+	}
+	return 0;
+}
+
+/*
+ * Sync state with the device and retrieve the requested field,
+ * whose index is specified in (kctl->private_value & 0xFF),
+ * from the received fields array.
+ */
+static int
+snd_s1810c_get_switch_state(struct usb_mixer_interface *mixer,
+			    struct snd_kcontrol *kctl, u32 *state)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	struct s1810_mixer_state *private = mixer->private_data;
+	u32 field = 0;
+	u32 ctl_idx = (u32) (kctl->private_value & 0xFF);
+	int ret;
+
+	guard(mutex)(&private->usb_mutex);
+	ret = snd_sc1810c_get_status_field(chip->dev, &field,
+					   ctl_idx, &private->seqnum);
+	if (ret < 0)
+		return ret;
+
+	*state = field;
+	return ret;
+}
+
+/*
+ * Send a control packet to the device for the control id
+ * specified in (kctl->private_value >> 8) with value
+ * specified in (kctl->private_value >> 16).
+ */
+static int
+snd_s1810c_set_switch_state(struct usb_mixer_interface *mixer,
+			    struct snd_kcontrol *kctl)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	struct s1810_mixer_state *private = mixer->private_data;
+	u32 pval = (u32) kctl->private_value;
+	u32 ctl_id = (pval >> 8) & 0xFF;
+	u32 ctl_val = (pval >> 16) & 0x1;
+
+	guard(mutex)(&private->usb_mutex);
+	return snd_s1810c_send_ctl_packet(chip->dev, 0, 0, 0, ctl_id, ctl_val);
+}
+
+/* Generic get/set/init functions for switch controls */
+
+static int
+snd_s1810c_switch_get(struct snd_kcontrol *kctl,
+		      struct snd_ctl_elem_value *ctl_elem)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+	struct s1810_mixer_state *private = mixer->private_data;
+	u32 pval = (u32) kctl->private_value;
+	u32 ctl_idx = pval & 0xFF;
+	u32 state = 0;
+	int ret;
+
+	CLASS(snd_usb_lock, pm)(mixer->chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	guard(mutex)(&private->data_mutex);
+	ret = snd_s1810c_get_switch_state(mixer, kctl, &state);
+	if (ret < 0)
+		return ret;
+
+	switch (ctl_idx) {
+	case SC1810C_STATE_LINE_SW:
+	case SC1810C_STATE_AB_SW:
+		ctl_elem->value.enumerated.item[0] = (int)state;
+		break;
+	default:
+		ctl_elem->value.integer.value[0] = (long)state;
+	}
+
+	return 0;
+}
+
+static int
+snd_s1810c_switch_set(struct snd_kcontrol *kctl,
+		      struct snd_ctl_elem_value *ctl_elem)
+{
+	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = list->mixer;
+	struct s1810_mixer_state *private = mixer->private_data;
+	u32 pval = (u32) kctl->private_value;
+	u32 ctl_idx = pval & 0xFF;
+	u32 curval = 0;
+	u32 newval = 0;
+	int ret = 0;
+
+	CLASS(snd_usb_lock, pm)(mixer->chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	guard(mutex)(&private->data_mutex);
+	ret = snd_s1810c_get_switch_state(mixer, kctl, &curval);
+	if (ret < 0)
+		return ret;
+
+	switch (ctl_idx) {
+	case SC1810C_STATE_LINE_SW:
+	case SC1810C_STATE_AB_SW:
+		newval = (u32) ctl_elem->value.enumerated.item[0];
+		break;
+	default:
+		newval = (u32) ctl_elem->value.integer.value[0];
+	}
+
+	if (curval == newval)
+		return 0;
+
+	kctl->private_value &= ~(0x1 << 16);
+	kctl->private_value |= (unsigned int)(newval & 0x1) << 16;
+	ret = snd_s1810c_set_switch_state(mixer, kctl);
+
+	return (ret < 0) ? 0 : 1;
+}
+
+static int
+snd_s1810c_switch_init(struct usb_mixer_interface *mixer,
+		       const struct snd_kcontrol_new *new_kctl)
+{
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *elem;
+
+	elem = kzalloc_obj(struct usb_mixer_elem_info);
+	if (!elem)
+		return -ENOMEM;
+
+	elem->head.mixer = mixer;
+	elem->control = 0;
+	elem->head.id = 0;
+	elem->channels = 1;
+
+	kctl = snd_ctl_new1(new_kctl, elem);
+	if (!kctl) {
+		kfree(elem);
+		return -ENOMEM;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	return snd_usb_mixer_add_control(&elem->head, kctl);
+}
+
+static int
+snd_s1810c_line_sw_info(struct snd_kcontrol *kctl,
+			struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[2] = {
+		"Preamp On (Mic/Inst)",
+		"Preamp Off (Line in)"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static const struct snd_kcontrol_new snd_s1810c_line_sw = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Line 1/2 Source Type",
+	.info = snd_s1810c_line_sw_info,
+	.get = snd_s1810c_switch_get,
+	.put = snd_s1810c_switch_set,
+	.private_value = (SC1810C_STATE_LINE_SW | SC1810C_CTL_LINE_SW << 8)
+};
+
+static const struct snd_kcontrol_new snd_s1810c_mute_sw = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Mute Main Out Switch",
+	.info = snd_ctl_boolean_mono_info,
+	.get = snd_s1810c_switch_get,
+	.put = snd_s1810c_switch_set,
+	.private_value = (SC1810C_STATE_MUTE_SW | SC1810C_CTL_MUTE_SW << 8)
+};
+
+static const struct snd_kcontrol_new snd_s1824c_mono_sw = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Mono Main Out Switch",
+	.info = snd_ctl_boolean_mono_info,
+	.get = snd_s1810c_switch_get,
+	.put = snd_s1810c_switch_set,
+	.private_value = (SC1824C_STATE_MONO_SW | SC1824C_CTL_MONO_SW << 8)
+};
+
+static const struct snd_kcontrol_new snd_s1810c_48v_sw = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "48V Phantom Power On Mic Inputs Switch",
+	.info = snd_ctl_boolean_mono_info,
+	.get = snd_s1810c_switch_get,
+	.put = snd_s1810c_switch_set,
+	.private_value = (SC1810C_STATE_48V_SW | SC1810C_CTL_48V_SW << 8)
+};
+
+static int
+snd_s1810c_ab_sw_info(struct snd_kcontrol *kctl,
+		      struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const texts[2] = {
+		"1/2",
+		"3/4"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts);
+}
+
+static const struct snd_kcontrol_new snd_s1810c_ab_sw = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Headphone 1 Source Route",
+	.info = snd_s1810c_ab_sw_info,
+	.get = snd_s1810c_switch_get,
+	.put = snd_s1810c_switch_set,
+	.private_value = (SC1810C_STATE_AB_SW | SC1810C_CTL_AB_SW << 8)
+};
+
+static void snd_sc1810_mixer_state_free(struct usb_mixer_interface *mixer)
+{
+	struct s1810_mixer_state *private = mixer->private_data;
+	kfree(private);
+	mixer->private_data = NULL;
+}
+
+/* Entry point, called from mixer_quirks.c */
+int snd_sc1810_init_mixer(struct usb_mixer_interface *mixer)
+{
+	struct s1810_mixer_state *private = NULL;
+	struct snd_usb_audio *chip = mixer->chip;
+	struct usb_device *dev = chip->dev;
+	int ret = 0;
+
+	/* Run this only once */
+	if (!list_empty(&chip->mixer_list))
+		return 0;
+
+	ret = snd_s1810c_init_mixer_maps(chip);
+	if (ret < 0)
+		return ret;
+
+	private = kzalloc_obj(struct s1810_mixer_state);
+	if (!private)
+		return -ENOMEM;
+
+	mutex_init(&private->usb_mutex);
+	mutex_init(&private->data_mutex);
+
+	mixer->private_data = private;
+	mixer->private_free = snd_sc1810_mixer_state_free;
+
+	private->seqnum = 1;
+
+	ret = snd_s1810c_switch_init(mixer, &snd_s1810c_line_sw);
+	if (ret < 0)
+		return ret;
+
+	ret = snd_s1810c_switch_init(mixer, &snd_s1810c_mute_sw);
+	if (ret < 0)
+		return ret;
+
+	ret = snd_s1810c_switch_init(mixer, &snd_s1810c_48v_sw);
+	if (ret < 0)
+		return ret;
+
+	switch (chip->usb_id) {
+	case USB_ID(0x194f, 0x010c): /* Presonus Studio 1810c */
+		dev_info(&dev->dev,
+			 "Presonus Studio 1810c, device_setup: %u\n", chip->setup);
+		if (chip->setup == 1)
+			dev_info(&dev->dev, "(8out/18in @ 48kHz)\n");
+		else if (chip->setup == 2)
+			dev_info(&dev->dev, "(6out/8in @ 192kHz)\n");
+		else
+			dev_info(&dev->dev, "(8out/14in @ 96kHz)\n");
+
+		ret = snd_s1810c_switch_init(mixer, &snd_s1810c_ab_sw);
+		if (ret < 0)
+			return ret;
+
+		break;
+	case USB_ID(0x194f, 0x0107): /* Presonus Studio 1824 */
+	case USB_ID(0x194f, 0x010d): /* Presonus Studio 1824c */
+		ret = snd_s1810c_switch_init(mixer, &snd_s1824c_mono_sw);
+		if (ret < 0)
+			return ret;
+
+		break;
+	}
+
+	return ret;
+}
diff --git a/sound/usb/mixer_s1810c.h b/sound/usb/mixer_s1810c.h
new file mode 100644
index 000000000..a79a3743c
--- /dev/null
+++ b/sound/usb/mixer_s1810c.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Presonus Studio 1810c driver for ALSA
+ * Copyright (C) 2019 Nick Kossifidis <mickflemm@gmail.com>
+ */
+
+int snd_sc1810_init_mixer(struct usb_mixer_interface *mixer);
diff --git a/sound/usb/mixer_scarlett.c b/sound/usb/mixer_scarlett.c
new file mode 100644
index 000000000..369968565
--- /dev/null
+++ b/sound/usb/mixer_scarlett.c
@@ -0,0 +1,1460 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Scarlett Driver for ALSA
+ *
+ *   Copyright (c) 2013 by Tobias Hoffmann
+ *   Copyright (c) 2013 by Robin Gareus <robin at gareus.org>
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai at suse.de>
+ *   Copyright (c) 2014 by Chris J Arges <chris.j.arges at canonical.com>
+ *
+ *   Many codes borrowed from audio.c by
+ *	    Alan Cox (alan at lxorguk.ukuu.org.uk)
+ *	    Thomas Sailer (sailer at ife.ee.ethz.ch)
+ *
+ *   Code cleanup:
+ *   David Henningsson <david.henningsson at canonical.com>
+ */
+
+/*
+ * Rewritten and extended to support more models, e.g. Scarlett 18i8.
+ *
+ * Auto-detection via UAC2 is not feasible to properly discover the vast
+ * majority of features. It's related to both Linux/ALSA's UAC2 as well as
+ * Focusrite's implementation of it. Eventually quirks may be sufficient but
+ * right now it's a major headache to work around these things.
+ *
+ * NB. Neither the OSX nor the win driver provided by Focusrite performs
+ * discovery, they seem to operate the same as this driver.
+ */
+
+/* Mixer Interface for the Focusrite Scarlett 18i6 audio interface.
+ *
+ * The protocol was reverse engineered by looking at communication between
+ * Scarlett MixControl (v 1.2.128.0) and the Focusrite(R) Scarlett 18i6
+ * (firmware v305) using wireshark and usbmon in January 2013.
+ * Extended in July 2013.
+ *
+ * this mixer gives complete access to all features of the device:
+ *  - change Impedance of inputs (Line-in, Mic / Instrument, Hi-Z)
+ *  - select clock source
+ *  - dynamic input to mixer-matrix assignment
+ *  - 18 x 6 mixer-matrix gain stages
+ *  - bus routing & volume control
+ *  - automatic re-initialization on connect if device was power-cycled
+ *
+ * USB URB commands overview (bRequest = 0x01 = UAC2_CS_CUR)
+ * wIndex
+ * 0x01 Analog Input line/instrument impedance switch, wValue=0x0901 +
+ *      channel, data=Line/Inst (2bytes)
+ *      pad (-10dB) switch, wValue=0x0b01 + channel, data=Off/On (2bytes)
+ *      ?? wValue=0x0803/04, ?? (2bytes)
+ * 0x0a Master Volume, wValue=0x0200+bus[0:all + only 1..4?] data(2bytes)
+ *      Bus Mute/Unmute wValue=0x0100+bus[0:all + only 1..4?], data(2bytes)
+ * 0x28 Clock source, wValue=0x0100, data={1:int,2:spdif,3:adat} (1byte)
+ * 0x29 Set Sample-rate, wValue=0x0100, data=sample-rate(4bytes)
+ * 0x32 Mixer mux, wValue=0x0600 + mixer-channel, data=input-to-connect(2bytes)
+ * 0x33 Output mux, wValue=bus, data=input-to-connect(2bytes)
+ * 0x34 Capture mux, wValue=0...18, data=input-to-connect(2bytes)
+ * 0x3c Matrix Mixer gains, wValue=mixer-node  data=gain(2bytes)
+ *      ?? [sometimes](4bytes, e.g 0x000003be 0x000003bf ...03ff)
+ *
+ * USB reads: (i.e. actually issued by original software)
+ * 0x01 wValue=0x0901+channel (1byte!!), wValue=0x0b01+channed (1byte!!)
+ * 0x29 wValue=0x0100 sample-rate(4bytes)
+ *      wValue=0x0200 ?? 1byte (only once)
+ * 0x2a wValue=0x0100 ?? 4bytes, sample-rate2 ??
+ *
+ * USB reads with bRequest = 0x03 = UAC2_CS_MEM
+ * 0x3c wValue=0x0002 1byte: sync status (locked=1)
+ *      wValue=0x0000 18*2byte: peak meter (inputs)
+ *      wValue=0x0001 8(?)*2byte: peak meter (mix)
+ *      wValue=0x0003 6*2byte: peak meter (pcm/daw)
+ *
+ * USB write with bRequest = 0x03
+ * 0x3c Save settings to hardware: wValue=0x005a, data=0xa5
+ *
+ *
+ * <ditaa>
+ *  /--------------\    18chn            6chn    /--------------\
+ *  | Hardware  in +--+-------\        /------+--+ ALSA PCM out |
+ *  \--------------/  |       |        |      |  \--------------/
+ *                    |       |        |      |
+ *                    |       v        v      |
+ *                    |   +---------------+   |
+ *                    |    \ Matrix  Mux /    |
+ *                    |     +-----+-----+     |
+ *                    |           |           |
+ *                    |           | 18chn     |
+ *                    |           v           |
+ *                    |     +-----------+     |
+ *                    |     | Mixer     |     |
+ *                    |     |    Matrix |     |
+ *                    |     |           |     |
+ *                    |     | 18x6 Gain |     |
+ *                    |     |   stages  |     |
+ *                    |     +-----+-----+     |
+ *                    |           |           |
+ *                    |           |           |
+ *                    | 18chn     | 6chn      | 6chn
+ *                    v           v           v
+ *                    =========================
+ *             +---------------+     +--—------------+
+ *              \ Output  Mux /       \ Capture Mux /
+ *               +-----+-----+         +-----+-----+
+ *                     |                     |
+ *                     | 6chn                |
+ *                     v                     |
+ *              +-------------+              |
+ *              | Master Gain |              |
+ *              +------+------+              |
+ *                     |                     |
+ *                     | 6chn                | 18chn
+ *                     | (3 stereo pairs)    |
+ *  /--------------\   |                     |   /--------------\
+ *  | Hardware out |<--/                     \-->| ALSA PCM  in |
+ *  \--------------/                             \--------------/
+ * </ditaa>
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio-v2.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/tlv.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "helper.h"
+#include "power.h"
+
+#include "mixer_scarlett.h"
+
+/* some gui mixers can't handle negative ctl values */
+#define SND_SCARLETT_LEVEL_BIAS 128
+#define SND_SCARLETT_MATRIX_IN_MAX 18
+#define SND_SCARLETT_CONTROLS_MAX 14
+#define SND_SCARLETT_OFFSETS_MAX 5
+
+enum {
+	SCARLETT_OUTPUTS,
+	SCARLETT_SWITCH_IMPEDANCE,
+	SCARLETT_SWITCH_PAD,
+	SCARLETT_SWITCH_GAIN,
+	FORTE_INPUT_SOURCE,     /* mic/line/instrument selection */
+	FORTE_INPUT_HPF,        /* high pass filter */
+	FORTE_INPUT_PHANTOM,    /* 48V phantom power */
+	FORTE_INPUT_PHASE,      /* phase invert */
+	FORTE_INPUT_PAD,        /* pad */
+	FORTE_INPUT_GAIN,       /* preamp gain 0-42 (~0-75dB for mic) */
+};
+
+enum {
+	SCARLETT_OFFSET_PCM = 0,
+	SCARLETT_OFFSET_ANALOG = 1,
+	SCARLETT_OFFSET_SPDIF = 2,
+	SCARLETT_OFFSET_ADAT = 3,
+	SCARLETT_OFFSET_MIX = 4,
+};
+
+struct scarlett_mixer_elem_enum_info {
+	int start;
+	int len;
+	int offsets[SND_SCARLETT_OFFSETS_MAX];
+	char const * const *names;
+};
+
+struct scarlett_mixer_control {
+	unsigned char num;
+	unsigned char type;
+	const char *name;
+};
+
+struct scarlett_device_info {
+	int matrix_in;
+	int matrix_out;
+	int input_len;
+	int output_len;
+
+	bool has_output_source_routing;
+
+	struct scarlett_mixer_elem_enum_info opt_master;
+	struct scarlett_mixer_elem_enum_info opt_matrix;
+
+	/* initial values for matrix mux */
+	int matrix_mux_init[SND_SCARLETT_MATRIX_IN_MAX];
+
+	int num_controls;	/* number of items in controls */
+	const struct scarlett_mixer_control controls[SND_SCARLETT_CONTROLS_MAX];
+};
+
+/********************** Enum Strings *************************/
+
+static const struct scarlett_mixer_elem_enum_info opt_pad = {
+	.start = 0,
+	.len = 2,
+	.offsets = {},
+	.names = (char const * const []){
+		"0dB", "-10dB"
+	}
+};
+
+static const struct scarlett_mixer_elem_enum_info opt_gain = {
+	.start = 0,
+	.len = 2,
+	.offsets = {},
+	.names = (char const * const []){
+		"Lo", "Hi"
+	}
+};
+
+static const struct scarlett_mixer_elem_enum_info opt_impedance = {
+	.start = 0,
+	.len = 2,
+	.offsets = {},
+	.names = (char const * const []){
+		"Line", "Hi-Z"
+	}
+};
+
+static const struct scarlett_mixer_elem_enum_info opt_clock = {
+	.start = 1,
+	.len = 3,
+	.offsets = {},
+	.names = (char const * const []){
+		"Internal", "SPDIF", "ADAT"
+	}
+};
+
+static const struct scarlett_mixer_elem_enum_info opt_sync = {
+	.start = 0,
+	.len = 2,
+	.offsets = {},
+	.names = (char const * const []){
+		"No Lock", "Locked"
+	}
+};
+
+/* Forte-specific input control options */
+static const struct scarlett_mixer_elem_enum_info opt_forte_source = {
+	.start = 0,
+	.len = 3,
+	.offsets = {},
+	.names = (char const * const []){
+		"Mic", "Line", "Inst"
+	}
+};
+
+/*
+ * Forte-specific USB control functions
+ * Forte input controls use bRequest=0x03 (UAC2_CS_MEM) instead of 0x01
+ * wValue = (control_code << 8) | channel
+ * wIndex = interface | (0x3c << 8) like Scarlett meter/matrix controls
+ */
+static int forte_set_ctl_value(struct usb_mixer_elem_info *elem, int value)
+{
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	unsigned char buf[2];
+	int wValue = elem->control;  /* Just control code, NO shift, NO channel */
+	int idx = snd_usb_ctrl_intf(elem->head.mixer->hostif) | (elem->head.id << 8);
+	int err;
+
+	/* Wiki format: "2 bytes, chan 0,1 and value"
+	 * Data order: [channel, value] - channel FIRST per wiki
+	 */
+	buf[0] = elem->idx_off;  /* Channel: 0 or 1 */
+	buf[1] = value & 0xff;   /* Value: 0-2 for source, 0-1 for switches */
+
+	err = snd_usb_lock_shutdown(chip);
+	if (err < 0)
+		return -EIO;
+
+	err = snd_usb_ctl_msg(chip->dev,
+			      usb_sndctrlpipe(chip->dev, 0),
+			      UAC2_CS_MEM,  /* bRequest = 0x03 */
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			      wValue, idx, buf, 2);
+
+	snd_usb_unlock_shutdown(chip);
+
+	if (err < 0) {
+		usb_audio_err(chip, "forte_set FAILED: req=0x03 wVal=0x%04x wIdx=0x%04x buf=[%02x,%02x] err=%d\n",
+			      wValue, idx, buf[0], buf[1], err);
+		return err;
+	}
+	return 0;
+}
+
+static int forte_get_ctl_value(struct usb_mixer_elem_info *elem, int *value)
+{
+	/* Device may not support reading input controls.
+	 * Return cached value or default to avoid blocking module load.
+	 */
+	if (elem->cached)
+		*value = elem->cache_val[0];
+	else
+		*value = 0;  /* Default: first option */
+
+	return 0;
+}
+
+/*
+ * Forte Input Gain control functions
+ * Gain range is 0-42 (0x00-0x2a) which maps to approximately:
+ * - Mic: 0 to +75dB (~1.8dB per step)
+ * - Instrument: +14 to +68dB
+ * - Line: -12 to +42dB
+ * We use a TLV scale of 0 to 7500 centidB (0 to 75dB) in ~179 cB steps
+ */
+#define FORTE_INPUT_GAIN_MAX 42
+
+static int forte_input_gain_info(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = FORTE_INPUT_GAIN_MAX;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static int forte_input_gain_get(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int err, val;
+
+	/* Use Forte-specific USB command with UAC2_CS_MEM */
+	err = forte_get_ctl_value(elem, &val);
+	if (err < 0)
+		return err;
+
+	ucontrol->value.integer.value[0] = clamp(val, 0, FORTE_INPUT_GAIN_MAX);
+	return 0;
+}
+
+static int forte_input_gain_put(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int err, oval, val;
+
+	/* Read current value */
+	err = forte_get_ctl_value(elem, &oval);
+	if (err < 0)
+		return err;
+
+	val = clamp((int)ucontrol->value.integer.value[0], 0, FORTE_INPUT_GAIN_MAX);
+	if (oval != val) {
+		/* Use Forte-specific USB command */
+		err = forte_set_ctl_value(elem, val);
+		if (err < 0)
+			return err;
+		elem->cached |= 1;
+		elem->cache_val[0] = val;
+		return 1;
+	}
+	return 0;
+}
+
+static int forte_input_gain_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
+
+	if (elem->cached)
+		forte_set_ctl_value(elem, *elem->cache_val);
+	return 0;
+}
+
+/*
+ * Forte-specific enum control functions (for Source selection)
+ * Uses bRequest=0x03 (UAC2_CS_MEM) instead of standard 0x01
+ */
+static int forte_ctl_enum_get(struct snd_kcontrol *kctl,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+	int err, val;
+
+	err = forte_get_ctl_value(elem, &val);
+	if (err < 0)
+		return err;
+
+	val = clamp(val - opt->start, 0, opt->len - 1);
+	ucontrol->value.enumerated.item[0] = val;
+	return 0;
+}
+
+static int forte_ctl_enum_put(struct snd_kcontrol *kctl,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+	int err, oval, val;
+
+	err = forte_get_ctl_value(elem, &oval);
+	if (err < 0)
+		return err;
+
+	val = ucontrol->value.integer.value[0] + opt->start;
+	if (val != oval) {
+		err = forte_set_ctl_value(elem, val);
+		if (err < 0)
+			return err;
+		elem->cached |= 1;
+		elem->cache_val[0] = val;
+		return 1;
+	}
+	return 0;
+}
+
+static int forte_ctl_enum_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
+
+	if (elem->cached)
+		forte_set_ctl_value(elem, *elem->cache_val);
+	return 0;
+}
+
+/*
+ * Forte-specific switch control functions (for HPF, 48V, Phase, Pad)
+ * Uses bRequest=0x03 (UAC2_CS_MEM) instead of standard 0x01
+ */
+static int forte_ctl_switch_get(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int err, val;
+
+	err = forte_get_ctl_value(elem, &val);
+	if (err < 0)
+		return err;
+
+	ucontrol->value.integer.value[0] = val ? 1 : 0;
+	return 0;
+}
+
+static int forte_ctl_switch_put(struct snd_kcontrol *kctl,
+				struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int err, oval, val;
+
+	err = forte_get_ctl_value(elem, &oval);
+	if (err < 0)
+		return err;
+
+	val = ucontrol->value.integer.value[0] ? 1 : 0;
+	if (val != oval) {
+		err = forte_set_ctl_value(elem, val);
+		if (err < 0)
+			return err;
+		elem->cached |= 1;
+		elem->cache_val[0] = val;
+		return 1;
+	}
+	return 0;
+}
+
+static int forte_ctl_switch_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
+
+	if (elem->cached)
+		forte_set_ctl_value(elem, *elem->cache_val);
+	return 0;
+}
+
+static int scarlett_ctl_switch_info(struct snd_kcontrol *kctl,
+		struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 1;
+	return 0;
+}
+
+static int scarlett_ctl_switch_get(struct snd_kcontrol *kctl,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int i, err, val;
+
+	for (i = 0; i < elem->channels; i++) {
+		err = snd_usb_get_cur_mix_value(elem, i, i, &val);
+		if (err < 0)
+			return err;
+
+		val = !val; /* invert mute logic for mixer */
+		ucontrol->value.integer.value[i] = val;
+	}
+
+	return 0;
+}
+
+static int scarlett_ctl_switch_put(struct snd_kcontrol *kctl,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int i, changed = 0;
+	int err, oval, val;
+
+	for (i = 0; i < elem->channels; i++) {
+		err = snd_usb_get_cur_mix_value(elem, i, i, &oval);
+		if (err < 0)
+			return err;
+
+		val = ucontrol->value.integer.value[i];
+		val = !val;
+		if (oval != val) {
+			err = snd_usb_set_cur_mix_value(elem, i, i, val);
+			if (err < 0)
+				return err;
+
+			changed = 1;
+		}
+	}
+
+	return changed;
+}
+
+static int scarlett_ctl_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
+	int i;
+
+	for (i = 0; i < elem->channels; i++)
+		if (elem->cached & (1 << i))
+			snd_usb_set_cur_mix_value(elem, i, i,
+						  elem->cache_val[i]);
+	return 0;
+}
+
+static int scarlett_ctl_info(struct snd_kcontrol *kctl,
+			     struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = (int)kctl->private_value +
+		SND_SCARLETT_LEVEL_BIAS;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static int scarlett_ctl_get(struct snd_kcontrol *kctl,
+			    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int i, err, val;
+
+	for (i = 0; i < elem->channels; i++) {
+		err = snd_usb_get_cur_mix_value(elem, i, i, &val);
+		if (err < 0)
+			return err;
+
+		val = clamp(val / 256, -128, (int)kctl->private_value) +
+				    SND_SCARLETT_LEVEL_BIAS;
+		ucontrol->value.integer.value[i] = val;
+	}
+
+	return 0;
+}
+
+static int scarlett_ctl_put(struct snd_kcontrol *kctl,
+			    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int i, changed = 0;
+	int err, oval, val;
+
+	for (i = 0; i < elem->channels; i++) {
+		err = snd_usb_get_cur_mix_value(elem, i, i, &oval);
+		if (err < 0)
+			return err;
+
+		val = ucontrol->value.integer.value[i] -
+			SND_SCARLETT_LEVEL_BIAS;
+		val = val * 256;
+		if (oval != val) {
+			err = snd_usb_set_cur_mix_value(elem, i, i, val);
+			if (err < 0)
+				return err;
+
+			changed = 1;
+		}
+	}
+
+	return changed;
+}
+
+static void scarlett_generate_name(int i, char *dst, size_t size, int offsets[])
+{
+	if (i > offsets[SCARLETT_OFFSET_MIX])
+		scnprintf(dst, size, "Mix %c",
+			  'A'+(i - offsets[SCARLETT_OFFSET_MIX] - 1));
+	else if (i > offsets[SCARLETT_OFFSET_ADAT])
+		scnprintf(dst, size, "ADAT %d", i - offsets[SCARLETT_OFFSET_ADAT]);
+	else if (i > offsets[SCARLETT_OFFSET_SPDIF])
+		scnprintf(dst, size, "SPDIF %d", i - offsets[SCARLETT_OFFSET_SPDIF]);
+	else if (i > offsets[SCARLETT_OFFSET_ANALOG])
+		scnprintf(dst, size, "Analog %d", i - offsets[SCARLETT_OFFSET_ANALOG]);
+	else if (i > offsets[SCARLETT_OFFSET_PCM])
+		scnprintf(dst, size, "PCM %d", i - offsets[SCARLETT_OFFSET_PCM]);
+	else
+		scnprintf(dst, size, "Off");
+}
+
+static int scarlett_ctl_enum_dynamic_info(struct snd_kcontrol *kctl,
+					  struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+	unsigned int items = opt->len;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
+	uinfo->count = elem->channels;
+	uinfo->value.enumerated.items = items;
+
+	if (uinfo->value.enumerated.item >= items)
+		uinfo->value.enumerated.item = items - 1;
+
+	/* generate name dynamically based on item number and offset info */
+	scarlett_generate_name(uinfo->value.enumerated.item,
+			       uinfo->value.enumerated.name,
+			       sizeof(uinfo->value.enumerated.name),
+			       opt->offsets);
+
+	return 0;
+}
+
+static int scarlett_ctl_enum_info(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+
+	return snd_ctl_enum_info(uinfo, elem->channels, opt->len,
+				 (const char * const *)opt->names);
+}
+
+static int scarlett_ctl_enum_get(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+	int err, val;
+
+	err = snd_usb_get_cur_mix_value(elem, 0, 0, &val);
+	if (err < 0)
+		return err;
+
+	val = clamp(val - opt->start, 0, opt->len-1);
+
+	ucontrol->value.enumerated.item[0] = val;
+
+	return 0;
+}
+
+static int scarlett_ctl_enum_put(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett_mixer_elem_enum_info *opt = elem->private_data;
+	int err, oval, val;
+
+	err = snd_usb_get_cur_mix_value(elem, 0, 0, &oval);
+	if (err < 0)
+		return err;
+
+	val = ucontrol->value.integer.value[0];
+	val = val + opt->start;
+	if (val != oval) {
+		err = snd_usb_set_cur_mix_value(elem, 0, 0, val);
+		if (err < 0)
+			return err;
+		return 1;
+	}
+	return 0;
+}
+
+static int scarlett_ctl_enum_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *elem = mixer_elem_list_to_info(list);
+
+	if (elem->cached)
+		snd_usb_set_cur_mix_value(elem, 0, 0, *elem->cache_val);
+	return 0;
+}
+
+static int scarlett_ctl_meter_get(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	unsigned char buf[2 * MAX_CHANNELS] = {0, };
+	int wValue = (elem->control << 8) | elem->idx_off;
+	int idx = snd_usb_ctrl_intf(elem->head.mixer->hostif) | (elem->head.id << 8);
+	int err;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	err = snd_usb_ctl_msg(chip->dev,
+				usb_rcvctrlpipe(chip->dev, 0),
+				UAC2_CS_MEM,
+				USB_RECIP_INTERFACE | USB_TYPE_CLASS |
+				USB_DIR_IN, wValue, idx, buf, elem->channels);
+	if (err < 0)
+		return err;
+
+	ucontrol->value.enumerated.item[0] = clamp((int)buf[0], 0, 1);
+	return 0;
+}
+
+static const struct snd_kcontrol_new usb_scarlett_ctl_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett_ctl_switch_info,
+	.get =  scarlett_ctl_switch_get,
+	.put =  scarlett_ctl_switch_put,
+};
+
+static const DECLARE_TLV_DB_SCALE(db_scale_scarlett_gain, -12800, 100, 0);
+
+static const struct snd_kcontrol_new usb_scarlett_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett_ctl_info,
+	.get =  scarlett_ctl_get,
+	.put =  scarlett_ctl_put,
+	.private_value = 6,  /* max value */
+	.tlv = { .p = db_scale_scarlett_gain }
+};
+
+static const struct snd_kcontrol_new usb_scarlett_ctl_master = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett_ctl_info,
+	.get =  scarlett_ctl_get,
+	.put =  scarlett_ctl_put,
+	.private_value = 6,  /* max value */
+	.tlv = { .p = db_scale_scarlett_gain }
+};
+
+static const struct snd_kcontrol_new usb_scarlett_ctl_enum = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett_ctl_enum_info,
+	.get =  scarlett_ctl_enum_get,
+	.put =  scarlett_ctl_enum_put,
+};
+
+static const struct snd_kcontrol_new usb_scarlett_ctl_dynamic_enum = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett_ctl_enum_dynamic_info,
+	.get =  scarlett_ctl_enum_get,
+	.put =  scarlett_ctl_enum_put,
+};
+
+static const struct snd_kcontrol_new usb_scarlett_ctl_sync = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+	.name = "",
+	.info = scarlett_ctl_enum_info,
+	.get =  scarlett_ctl_meter_get,
+};
+
+/* Forte-specific control structures - use bRequest=0x03 instead of 0x01 */
+static const struct snd_kcontrol_new usb_forte_ctl_enum = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett_ctl_enum_info,
+	.get =  forte_ctl_enum_get,
+	.put =  forte_ctl_enum_put,
+};
+
+static const struct snd_kcontrol_new usb_forte_ctl_switch = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get =  forte_ctl_switch_get,
+	.put =  forte_ctl_switch_put,
+};
+
+/* Forte input gain: 0-42 maps to approximately 0-75dB (~179 cB per step) */
+static const DECLARE_TLV_DB_SCALE(db_scale_forte_input_gain, 0, 179, 0);
+
+static const struct snd_kcontrol_new usb_forte_ctl_input_gain = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = forte_input_gain_info,
+	.get =  forte_input_gain_get,
+	.put =  forte_input_gain_put,
+	.tlv = { .p = db_scale_forte_input_gain }
+};
+
+static int add_new_ctl(struct usb_mixer_interface *mixer,
+		       const struct snd_kcontrol_new *ncontrol,
+		       usb_mixer_elem_resume_func_t resume,
+		       int index, int offset, int num,
+		       int val_type, int channels, const char *name,
+		       const struct scarlett_mixer_elem_enum_info *opt,
+		       struct usb_mixer_elem_info **elem_ret
+)
+{
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *elem;
+	int err;
+
+	elem = kzalloc_obj(*elem);
+	if (!elem)
+		return -ENOMEM;
+
+	elem->head.mixer = mixer;
+	elem->head.resume = resume;
+	elem->control = offset;
+	elem->idx_off = num;
+	elem->head.id = index;
+	elem->val_type = val_type;
+
+	elem->channels = channels;
+
+	/* add scarlett_mixer_elem_enum_info struct */
+	elem->private_data = (void *)opt;
+
+	kctl = snd_ctl_new1(ncontrol, elem);
+	if (!kctl) {
+		kfree(elem);
+		return -ENOMEM;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	strscpy(kctl->id.name, name, sizeof(kctl->id.name));
+
+	err = snd_usb_mixer_add_control(&elem->head, kctl);
+	if (err < 0)
+		return err;
+
+	if (elem_ret)
+		*elem_ret = elem;
+
+	return 0;
+}
+
+static int add_output_ctls(struct usb_mixer_interface *mixer,
+			   int index, const char *name,
+			   const struct scarlett_device_info *info)
+{
+	int err;
+	char mx[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	struct usb_mixer_elem_info *elem;
+
+	/* Add mute switch */
+	snprintf(mx, sizeof(mx), "Master %d (%s) Playback Switch",
+		index + 1, name);
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_switch,
+			  scarlett_ctl_resume, 0x0a, 0x01,
+			  2*index+1, USB_MIXER_S16, 2, mx, NULL, &elem);
+	if (err < 0)
+		return err;
+
+	/* Add volume control and initialize to 0 */
+	snprintf(mx, sizeof(mx), "Master %d (%s) Playback Volume",
+		index + 1, name);
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_master,
+			  scarlett_ctl_resume, 0x0a, 0x02,
+			  2*index+1, USB_MIXER_S16, 2, mx, NULL, &elem);
+	if (err < 0)
+		return err;
+
+	/* Add L/R source routing if device supports it */
+	if (info->has_output_source_routing) {
+		/* Add L channel source playback enumeration */
+		snprintf(mx, sizeof(mx), "Master %dL (%s) Source Playback Enum",
+			index + 1, name);
+		err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+				  scarlett_ctl_enum_resume, 0x33, 0x00,
+				  2*index, USB_MIXER_S16, 1, mx, &info->opt_master,
+				  &elem);
+		if (err < 0)
+			return err;
+
+		/* Add R channel source playback enumeration */
+		snprintf(mx, sizeof(mx), "Master %dR (%s) Source Playback Enum",
+			index + 1, name);
+		err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+				  scarlett_ctl_enum_resume, 0x33, 0x00,
+				  2*index+1, USB_MIXER_S16, 1, mx, &info->opt_master,
+				  &elem);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/********************** device-specific config *************************/
+
+static const struct scarlett_device_info forte_info = {
+	.matrix_in = 6,
+	.matrix_out = 4,
+	.input_len = 2,
+	.output_len = 4,
+	.has_output_source_routing = false,
+
+	.opt_master = {
+		.start = -1,
+		.len = 13,
+		.offsets = {0, 4, 6, 6, 6},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 7,
+		.offsets = {0, 4, 6, 6, 6},
+		.names = NULL
+	},
+
+	.num_controls = 14,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Line Out" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone" },
+		/* Input 1 controls */
+		{ .num = 1, .type = FORTE_INPUT_GAIN, .name = NULL},
+		{ .num = 1, .type = FORTE_INPUT_SOURCE, .name = NULL},
+		{ .num = 1, .type = FORTE_INPUT_HPF, .name = NULL},
+		{ .num = 1, .type = FORTE_INPUT_PHANTOM, .name = NULL},
+		{ .num = 1, .type = FORTE_INPUT_PHASE, .name = NULL},
+		{ .num = 1, .type = FORTE_INPUT_PAD, .name = NULL},
+		/* Input 2 controls */
+		{ .num = 2, .type = FORTE_INPUT_GAIN, .name = NULL},
+		{ .num = 2, .type = FORTE_INPUT_SOURCE, .name = NULL},
+		{ .num = 2, .type = FORTE_INPUT_HPF, .name = NULL},
+		{ .num = 2, .type = FORTE_INPUT_PHANTOM, .name = NULL},
+		{ .num = 2, .type = FORTE_INPUT_PHASE, .name = NULL},
+		{ .num = 2, .type = FORTE_INPUT_PAD, .name = NULL},
+	},
+};
+
+/*  untested...  */
+static const struct scarlett_device_info s6i6_info = {
+	.matrix_in = 18,
+	.matrix_out = 8,
+	.input_len = 6,
+	.output_len = 6,
+	.has_output_source_routing = true,
+
+	.opt_master = {
+		.start = -1,
+		.len = 27,
+		.offsets = {0, 12, 16, 18, 18},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 19,
+		.offsets = {0, 12, 16, 18, 18},
+		.names = NULL
+	},
+
+	.num_controls = 9,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 1, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 3, .type = SCARLETT_SWITCH_GAIN, .name = NULL},
+		{ .num = 4, .type = SCARLETT_SWITCH_GAIN, .name = NULL},
+	},
+
+	.matrix_mux_init = {
+		12, 13, 14, 15,                 /* Analog -> 1..4 */
+		16, 17,                          /* SPDIF -> 5,6 */
+		0, 1, 2, 3, 4, 5, 6, 7,     /* PCM[1..12] -> 7..18 */
+		8, 9, 10, 11
+	}
+};
+
+/*  untested...  */
+static const struct scarlett_device_info s8i6_info = {
+	.matrix_in = 18,
+	.matrix_out = 6,
+	.input_len = 8,
+	.output_len = 6,
+	.has_output_source_routing = true,
+
+	.opt_master = {
+		.start = -1,
+		.len = 25,
+		.offsets = {0, 12, 16, 18, 18},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 19,
+		.offsets = {0, 12, 16, 18, 18},
+		.names = NULL
+	},
+
+	.num_controls = 7,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 3, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 4, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+	},
+
+	.matrix_mux_init = {
+		12, 13, 14, 15,                 /* Analog -> 1..4 */
+		16, 17,                          /* SPDIF -> 5,6 */
+		0, 1, 2, 3, 4, 5, 6, 7,     /* PCM[1..12] -> 7..18 */
+		8, 9, 10, 11
+	}
+};
+
+static const struct scarlett_device_info s18i6_info = {
+	.matrix_in = 18,
+	.matrix_out = 6,
+	.input_len = 18,
+	.output_len = 6,
+	.has_output_source_routing = true,
+
+	.opt_master = {
+		.start = -1,
+		.len = 31,
+		.offsets = {0, 6, 14, 16, 24},
+		.names = NULL,
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 25,
+		.offsets = {0, 6, 14, 16, 24},
+		.names = NULL,
+	},
+
+	.num_controls = 5,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+	},
+
+	.matrix_mux_init = {
+		 6,  7,  8,  9, 10, 11, 12, 13, /* Analog -> 1..8 */
+		16, 17, 18, 19, 20, 21,     /* ADAT[1..6] -> 9..14 */
+		14, 15,                          /* SPDIF -> 15,16 */
+		0, 1                          /* PCM[1,2] -> 17,18 */
+	}
+};
+
+static const struct scarlett_device_info s18i8_info = {
+	.matrix_in = 18,
+	.matrix_out = 8,
+	.input_len = 18,
+	.output_len = 8,
+	.has_output_source_routing = true,
+
+	.opt_master = {
+		.start = -1,
+		.len = 35,
+		.offsets = {0, 8, 16, 18, 26},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 27,
+		.offsets = {0, 8, 16, 18, 26},
+		.names = NULL
+	},
+
+	.num_controls = 10,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Headphone 1" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "Headphone 2" },
+		{ .num = 3, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 1, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 3, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 4, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+	},
+
+	.matrix_mux_init = {
+		 8,  9, 10, 11, 12, 13, 14, 15, /* Analog -> 1..8 */
+		18, 19, 20, 21, 22, 23,     /* ADAT[1..6] -> 9..14 */
+		16, 17,                          /* SPDIF -> 15,16 */
+		0, 1                          /* PCM[1,2] -> 17,18 */
+	}
+};
+
+static const struct scarlett_device_info s18i20_info = {
+	.matrix_in = 18,
+	.matrix_out = 8,
+	.input_len = 18,
+	.output_len = 20,
+	.has_output_source_routing = true,
+
+	.opt_master = {
+		.start = -1,
+		.len = 47,
+		.offsets = {0, 20, 28, 30, 38},
+		.names = NULL
+	},
+
+	.opt_matrix = {
+		.start = -1,
+		.len = 39,
+		.offsets = {0, 20, 28, 30, 38},
+		.names = NULL
+	},
+
+	.num_controls = 10,
+	.controls = {
+		{ .num = 0, .type = SCARLETT_OUTPUTS, .name = "Monitor" },
+		{ .num = 1, .type = SCARLETT_OUTPUTS, .name = "Line 3/4" },
+		{ .num = 2, .type = SCARLETT_OUTPUTS, .name = "Line 5/6" },
+		{ .num = 3, .type = SCARLETT_OUTPUTS, .name = "Line 7/8" },
+		{ .num = 4, .type = SCARLETT_OUTPUTS, .name = "Line 9/10" },
+		{ .num = 5, .type = SCARLETT_OUTPUTS, .name = "SPDIF" },
+		{ .num = 6, .type = SCARLETT_OUTPUTS, .name = "ADAT 1/2" },
+		{ .num = 7, .type = SCARLETT_OUTPUTS, .name = "ADAT 3/4" },
+		{ .num = 8, .type = SCARLETT_OUTPUTS, .name = "ADAT 5/6" },
+		{ .num = 9, .type = SCARLETT_OUTPUTS, .name = "ADAT 7/8" },
+		/*{ .num = 1, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 1, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_IMPEDANCE, .name = NULL},
+		{ .num = 2, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 3, .type = SCARLETT_SWITCH_PAD, .name = NULL},
+		{ .num = 4, .type = SCARLETT_SWITCH_PAD, .name = NULL},*/
+	},
+
+	.matrix_mux_init = {
+		20, 21, 22, 23, 24, 25, 26, 27, /* Analog -> 1..8 */
+		30, 31, 32, 33, 34, 35,     /* ADAT[1..6] -> 9..14 */
+		28, 29,                          /* SPDIF -> 15,16 */
+		0, 1                          /* PCM[1,2] -> 17,18 */
+	}
+};
+
+
+static int scarlett_controls_create_generic(struct usb_mixer_interface *mixer,
+	const struct scarlett_device_info *info)
+{
+	int i, err;
+	char mx[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	const struct scarlett_mixer_control *ctl;
+	struct usb_mixer_elem_info *elem;
+
+	/* create master switch and playback volume */
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_switch,
+			  scarlett_ctl_resume, 0x0a, 0x01, 0,
+			  USB_MIXER_S16, 1, "Master Playback Switch", NULL,
+			  &elem);
+	if (err < 0)
+		return err;
+
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_master,
+			  scarlett_ctl_resume, 0x0a, 0x02, 0,
+			  USB_MIXER_S16, 1, "Master Playback Volume", NULL,
+			  &elem);
+	if (err < 0)
+		return err;
+
+	/* iterate through controls in info struct and create each one */
+	for (i = 0; i < info->num_controls; i++) {
+		ctl = &info->controls[i];
+
+		switch (ctl->type) {
+		case SCARLETT_OUTPUTS:
+			err = add_output_ctls(mixer, ctl->num, ctl->name, info);
+			if (err < 0)
+				return err;
+			break;
+		case SCARLETT_SWITCH_IMPEDANCE:
+			scnprintf(mx, sizeof(mx),
+				  "Input %d Impedance Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_scarlett_ctl_enum,
+					  scarlett_ctl_enum_resume, 0x01,
+					  0x09, ctl->num, USB_MIXER_S16, 1, mx,
+					  &opt_impedance, &elem);
+			if (err < 0)
+				return err;
+			break;
+		case SCARLETT_SWITCH_PAD:
+			scnprintf(mx, sizeof(mx),
+				  "Input %d Pad Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_scarlett_ctl_enum,
+					  scarlett_ctl_enum_resume, 0x01,
+					  0x0b, ctl->num, USB_MIXER_S16, 1, mx,
+					  &opt_pad, &elem);
+			if (err < 0)
+				return err;
+			break;
+		case SCARLETT_SWITCH_GAIN:
+			scnprintf(mx, sizeof(mx),
+				  "Input %d Gain Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_scarlett_ctl_enum,
+					  scarlett_ctl_enum_resume, 0x01,
+					  0x08, ctl->num, USB_MIXER_S16, 1, mx,
+					  &opt_gain, &elem);
+			if (err < 0)
+				return err;
+			break;
+		/* Forte input controls - use wIndex 0x3c per wiki docs */
+		case FORTE_INPUT_GAIN:
+			sprintf(mx, "Line In %d Gain Capture Volume", ctl->num);
+			err = add_new_ctl(mixer, &usb_forte_ctl_input_gain,
+					  forte_input_gain_resume, 0x3c,
+					  0x06, ctl->num - 1, USB_MIXER_S16, 1, mx,
+					  NULL, &elem);
+			if (err < 0)
+				return err;
+			break;
+		case FORTE_INPUT_SOURCE:
+			sprintf(mx, "Input %d Source", ctl->num);
+			err = add_new_ctl(mixer, &usb_forte_ctl_enum,
+					  forte_ctl_enum_resume, 0x3c,
+					  0x07, ctl->num - 1, USB_MIXER_S16, 1, mx,
+					  &opt_forte_source, &elem);
+			if (err < 0)
+				return err;
+			break;
+		case FORTE_INPUT_HPF:
+			sprintf(mx, "Input %d High Pass Filter Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_forte_ctl_switch,
+					  forte_ctl_switch_resume, 0x3c,
+					  0x08, ctl->num - 1, USB_MIXER_S16, 1, mx,
+					  NULL, &elem);
+			if (err < 0)
+				return err;
+			break;
+		case FORTE_INPUT_PHANTOM:
+			sprintf(mx, "Input %d 48V Phantom Power Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_forte_ctl_switch,
+					  forte_ctl_switch_resume, 0x3c,
+					  0x09, ctl->num - 1, USB_MIXER_S16, 1, mx,
+					  NULL, &elem);
+			if (err < 0)
+				return err;
+			break;
+		case FORTE_INPUT_PHASE:
+			sprintf(mx, "Input %d Phase Invert Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_forte_ctl_switch,
+					  forte_ctl_switch_resume, 0x3c,
+					  0x0a, ctl->num - 1, USB_MIXER_S16, 1, mx,
+					  NULL, &elem);
+			if (err < 0)
+				return err;
+			break;
+		case FORTE_INPUT_PAD:
+			sprintf(mx, "Input %d Pad Switch", ctl->num);
+			err = add_new_ctl(mixer, &usb_forte_ctl_switch,
+					  forte_ctl_switch_resume, 0x3c,
+					  0x0b, ctl->num - 1, USB_MIXER_S16, 1, mx,
+					  NULL, &elem);
+			if (err < 0)
+				return err;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Create and initialize a mixer for the Focusrite(R) Scarlett
+ */
+int snd_scarlett_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err, i, o;
+	char mx[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	const struct scarlett_device_info *info;
+	struct usb_mixer_elem_info *elem;
+	static char sample_rate_buffer[4] = { '\x80', '\xbb', '\x00', '\x00' };
+
+	/* only use UAC_VERSION_2 */
+	if (!mixer->protocol)
+		return 0;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x1235, 0x8012):
+		info = &s6i6_info;
+		break;
+	case USB_ID(0x1235, 0x8002):
+		info = &s8i6_info;
+		break;
+	case USB_ID(0x1235, 0x8004):
+		info = &s18i6_info;
+		break;
+	case USB_ID(0x1235, 0x8014):
+		info = &s18i8_info;
+		break;
+	case USB_ID(0x1235, 0x800c):
+		info = &s18i20_info;
+		break;
+	default: /* device not (yet) supported */
+		return -EINVAL;
+	}
+
+	/* generic function to create controls */
+	err = scarlett_controls_create_generic(mixer, info);
+	if (err < 0)
+		return err;
+
+	/* setup matrix controls */
+	for (i = 0; i < info->matrix_in; i++) {
+		snprintf(mx, sizeof(mx), "Matrix %02d Input Playback Route",
+			 i+1);
+		err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+				  scarlett_ctl_enum_resume, 0x32,
+				  0x06, i, USB_MIXER_S16, 1, mx,
+				  &info->opt_matrix, &elem);
+		if (err < 0)
+			return err;
+
+		for (o = 0; o < info->matrix_out; o++) {
+			scnprintf(mx, sizeof(mx),
+				  "Matrix %02d Mix %c Playback Volume", i+1,
+				  o+'A');
+			err = add_new_ctl(mixer, &usb_scarlett_ctl,
+					  scarlett_ctl_resume, 0x3c, 0x00,
+					  (i << 3) + (o & 0x07), USB_MIXER_S16,
+					  1, mx, NULL, &elem);
+			if (err < 0)
+				return err;
+
+		}
+	}
+
+	for (i = 0; i < info->input_len; i++) {
+		snprintf(mx, sizeof(mx), "Input Source %02d Capture Route",
+			 i+1);
+		err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+				  scarlett_ctl_enum_resume, 0x34,
+				  0x00, i, USB_MIXER_S16, 1, mx,
+				  &info->opt_master, &elem);
+		if (err < 0)
+			return err;
+	}
+
+	/* val_len == 1 needed here */
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_enum,
+			  scarlett_ctl_enum_resume, 0x28, 0x01, 0,
+			  USB_MIXER_U8, 1, "Sample Clock Source",
+			  &opt_clock, &elem);
+	if (err < 0)
+		return err;
+
+	/* val_len == 1 and UAC2_CS_MEM */
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_sync, NULL, 0x3c, 0x00, 2,
+			  USB_MIXER_U8, 1, "Sample Clock Sync Status",
+			  &opt_sync, &elem);
+	if (err < 0)
+		return err;
+
+	/* initialize sampling rate to 48000 */
+	err = snd_usb_ctl_msg(mixer->chip->dev,
+		usb_sndctrlpipe(mixer->chip->dev, 0), UAC2_CS_CUR,
+		USB_RECIP_INTERFACE | USB_TYPE_CLASS |
+		USB_DIR_OUT, 0x0100, snd_usb_ctrl_intf(mixer->hostif) |
+		(0x29 << 8), sample_rate_buffer, 4);
+	if (err < 0)
+		return err;
+
+	return err;
+}
+
+/*
+ * Create and initialize a mixer for the Focusrite(R) Forte
+ */
+int snd_forte_controls_create(struct usb_mixer_interface *mixer)
+{
+	int err, i, o;
+	char mx[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	const struct scarlett_device_info *info;
+	struct usb_mixer_elem_info *elem;
+
+	/* only use UAC_VERSION_2 */
+	if (!mixer->protocol)
+		return 0;
+
+	switch (mixer->chip->usb_id) {
+	case USB_ID(0x1235, 0x8010):
+		info = &forte_info;
+		break;
+	default: /* device not (yet) supported */
+		return -EINVAL;
+	}
+
+	/* generic function to create controls */
+	err = scarlett_controls_create_generic(mixer, info);
+	if (err < 0)
+		return err;
+
+	/* setup matrix controls */
+	for (i = 0; i < info->matrix_in; i++) {
+		snprintf(mx, sizeof(mx), "Matrix %02d Input Playback Route",
+			 i+1);
+		err = add_new_ctl(mixer, &usb_scarlett_ctl_dynamic_enum,
+				  scarlett_ctl_enum_resume, 0x32,
+				  0x06, i, USB_MIXER_S16, 1, mx,
+				  &info->opt_matrix, &elem);
+		if (err < 0)
+			return err;
+
+		for (o = 0; o < info->matrix_out; o++) {
+			sprintf(mx, "Matrix %02d Mix %c Playback Volume", i+1,
+				o+'A');
+			err = add_new_ctl(mixer, &usb_scarlett_ctl,
+					  scarlett_ctl_resume, 0x3c, 0x01,
+					  (i << 2) + (o & 0x03), USB_MIXER_S16,
+					  1, mx, NULL, &elem);
+			if (err < 0)
+				return err;
+
+		}
+	}
+
+	/* val_len == 1 and UAC2_CS_MEM */
+	err = add_new_ctl(mixer, &usb_scarlett_ctl_sync, NULL, 0x3c, 0x00, 2,
+			  USB_MIXER_U8, 1, "Sample Clock Sync Status",
+			  &opt_sync, &elem);
+	if (err < 0)
+		return err;
+
+	return err;
+}
diff --git a/sound/usb/mixer_scarlett.h b/sound/usb/mixer_scarlett.h
new file mode 100644
index 000000000..c44fe7d72
--- /dev/null
+++ b/sound/usb/mixer_scarlett.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USB_MIXER_SCARLETT_H
+#define __USB_MIXER_SCARLETT_H
+
+int snd_scarlett_controls_create(struct usb_mixer_interface *mixer);
+int snd_forte_controls_create(struct usb_mixer_interface *mixer);
+
+#endif /* __USB_MIXER_SCARLETT_H */
diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c
new file mode 100644
index 000000000..ed5fe746d
--- /dev/null
+++ b/sound/usb/mixer_scarlett2.c
@@ -0,0 +1,9935 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *   Focusrite Scarlett 2 Protocol Driver for ALSA
+ *   (including Scarlett 2nd Gen, 3rd Gen, 4th Gen, Clarett USB, and
+ *   Clarett+ series products)
+ *
+ *   Supported models:
+ *   - 6i6/18i8/18i20 Gen 2
+ *   - Solo/2i2/4i4/8i6/18i8/18i20 Gen 3
+ *   - Solo/2i2/4i4 Gen 4
+ *   - Clarett 2Pre/4Pre/8Pre USB
+ *   - Clarett+ 2Pre/4Pre/8Pre
+ *   - Vocaster One/Two
+ *
+ *   Copyright (c) 2018-2025 by Geoffrey D. Bennett <g at b4.vu>
+ *   Copyright (c) 2020-2021 by Vladimir Sadovnikov <sadko4u@gmail.com>
+ *   Copyright (c) 2022 by Christian Colglazier <christian@cacolglazier.com>
+ *
+ *   Based on the Scarlett (Gen 1) Driver for ALSA:
+ *
+ *   Copyright (c) 2013 by Tobias Hoffmann
+ *   Copyright (c) 2013 by Robin Gareus <robin at gareus.org>
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai at suse.de>
+ *   Copyright (c) 2014 by Chris J Arges <chris.j.arges at canonical.com>
+ *
+ *   Many codes borrowed from audio.c by
+ *     Alan Cox (alan at lxorguk.ukuu.org.uk)
+ *     Thomas Sailer (sailer at ife.ee.ethz.ch)
+ *
+ *   Code cleanup:
+ *   David Henningsson <david.henningsson at canonical.com>
+ */
+
+/* The protocol was reverse engineered by looking at the communication
+ * between Focusrite Control 2.3.4 and the Focusrite(R) Scarlett 18i20
+ * (firmware 1083) using usbmon in July-August 2018.
+ *
+ * Scarlett 18i8 support added in April 2019.
+ *
+ * Scarlett 6i6 support added in June 2019 (thanks to Martin Wittmann
+ * for providing usbmon output and testing).
+ *
+ * Scarlett 4i4/8i6 Gen 3 support added in May 2020 (thanks to Laurent
+ * Debricon for donating a 4i4 and to Fredrik Unger for providing 8i6
+ * usbmon output and testing).
+ *
+ * Scarlett 18i8/18i20 Gen 3 support added in June 2020 (thanks to
+ * Darren Jaeckel, Alex Sedlack, and Clovis Lunel for providing usbmon
+ * output, protocol traces and testing).
+ *
+ * Support for loading mixer volume and mux configuration from the
+ * interface during driver initialisation added in May 2021 (thanks to
+ * Vladimir Sadovnikov for figuring out how).
+ *
+ * Support for Solo/2i2 Gen 3 added in May 2021 (thanks to Alexander
+ * Vorona for 2i2 protocol traces).
+ *
+ * Support for phantom power, direct monitoring, speaker switching,
+ * and talkback added in May-June 2021.
+ *
+ * Support for Clarett+ 8Pre added in Aug 2022 by Christian
+ * Colglazier.
+ *
+ * Support for Clarett 8Pre USB added in Sep 2023 (thanks to Philippe
+ * Perrot for confirmation).
+ *
+ * Support for Clarett+ 4Pre and 2Pre added in Sep 2023 (thanks to
+ * Gregory Rozzo for donating a 4Pre, and David Sherwood and Patrice
+ * Peterson for usbmon output).
+ *
+ * Support for Clarett 2Pre and 4Pre USB added in Oct 2023.
+ *
+ * Support for firmware updates added in Dec 2023.
+ *
+ * Support for Scarlett Solo/2i2/4i4 Gen 4 added in Dec 2023 (thanks
+ * to many LinuxMusicians people and to Focusrite for hardware
+ * donations).
+ *
+ * Support for Vocaster One and Two added in Mar 2024 (thanks to many
+ * LinuxMusicians people and to Focusrite for hardware donations).
+ *
+ * This ALSA mixer gives access to (model-dependent):
+ *  - input, output, mixer-matrix muxes
+ *  - mixer-matrix gain stages
+ *  - gain/volume/mute controls
+ *  - level meters
+ *  - line/inst level, pad, and air controls
+ *  - phantom power, direct monitor, speaker switching, and talkback
+ *    controls
+ *  - disable/enable MSD mode
+ *  - disable/enable standalone mode
+ *  - input mute, gain, autogain, safe mode
+ *  - direct monitor mixes
+ *  - compressor and EQ
+ *  - Bluetooth volume
+ *
+ * <ditaa>
+ *    /--------------\    18chn            20chn     /--------------\
+ *    | Hardware  in +--+------\    /-------------+--+ ALSA PCM out |
+ *    \--------------/  |      |    |             |  \--------------/
+ *                      |      |    |    /-----\  |
+ *                      |      |    |    |     |  |
+ *                      |      v    v    v     |  |
+ *                      |   +---------------+  |  |
+ *                      |    \ Matrix  Mux /   |  |
+ *                      |     +-----+-----+    |  |
+ *                      |           |          |  |
+ *                      |           |18chn     |  |
+ *                      |           |          |  |
+ *                      |           |     10chn|  |
+ *                      |           v          |  |
+ *                      |     +------------+   |  |
+ *                      |     | Mixer      |   |  |
+ *                      |     |     Matrix |   |  |
+ *                      |     |            |   |  |
+ *                      |     | 18x10 Gain |   |  |
+ *                      |     |   stages   |   |  |
+ *                      |     +-----+------+   |  |
+ *                      |           |          |  |
+ *                      |18chn      |10chn     |  |20chn
+ *                      |           |          |  |
+ *                      |           +----------/  |
+ *                      |           |             |
+ *                      v           v             v
+ *                      ===========================
+ *               +---------------+       +--—------------+
+ *                \ Output  Mux /         \ Capture Mux /
+ *                 +---+---+---+           +-----+-----+
+ *                     |   |                     |
+ *                10chn|   |                     |18chn
+ *                     |   |                     |
+ *  /--------------\   |   |                     |   /--------------\
+ *  | S/PDIF, ADAT |<--/   |10chn                \-->| ALSA PCM in  |
+ *  | Hardware out |       |                         \--------------/
+ *  \--------------/       |
+ *                         v
+ *                  +-------------+    Software gain per channel.
+ *                  | Master Gain |<-- 18i20 only: Switch per channel
+ *                  +------+------+    to select HW or SW gain control.
+ *                         |
+ *                         |10chn
+ *  /--------------\       |
+ *  | Analogue     |<------/
+ *  | Hardware out |
+ *  \--------------/
+ * </ditaa>
+ *
+ * Gen 3/4 devices have a Mass Storage Device (MSD) mode where a small
+ * disk with registration and driver download information is presented
+ * to the host. To access the full functionality of the device without
+ * proprietary software, MSD mode can be disabled by:
+ * - holding down the 48V button for five seconds while powering on
+ *   the device, or
+ * - using this driver and alsamixer to change the "MSD Mode" setting
+ *   to Off and power-cycling the device
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/moduleparam.h>
+
+#include <sound/control.h>
+#include <sound/tlv.h>
+#include <sound/hwdep.h>
+
+#include <uapi/sound/scarlett2.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "helper.h"
+
+#include "mixer_scarlett2.h"
+#include "fcp.h"
+
+/* device_setup value to allow turning MSD mode back on */
+#define SCARLETT2_MSD_ENABLE 0x02
+
+/* device_setup value to disable this mixer driver */
+#define SCARLETT2_DISABLE 0x04
+
+/* device_setup value to use the FCP driver instead */
+#define SCARLETT2_USE_FCP_DRIVER 0x08
+
+/* some gui mixers can't handle negative ctl values */
+#define SCARLETT2_VOLUME_BIAS 127
+
+/* maximum preamp input gain value
+ * (the corresponding value in dB is per-device)
+ */
+#define SCARLETT2_MAX_GAIN_VALUE 70
+
+/* maximum Bluetooth volume value */
+#define SCARLETT2_MAX_BLUETOOTH_VOLUME 30
+
+/* maximum front-panel sleep time in seconds (24 hours) */
+#define SCARLETT2_MAX_FP_SLEEP_TIME 86400
+
+/* mixer range from -80dB to +12dB in 0.5dB steps */
+#define SCARLETT2_MIXER_MIN_DB -80
+#define SCARLETT2_MIXER_BIAS (-SCARLETT2_MIXER_MIN_DB * 2)
+#define SCARLETT2_MIXER_MAX_DB 12
+#define SCARLETT2_MIXER_MAX_VALUE \
+	((SCARLETT2_MIXER_MAX_DB - SCARLETT2_MIXER_MIN_DB) * 2)
+#define SCARLETT2_MIXER_VALUE_COUNT (SCARLETT2_MIXER_MAX_VALUE + 1)
+
+/* map from (dB + 80) * 2 to mixer value
+ * for dB in 0 .. 184: int(8192 * pow(10, ((dB - 160) / 2 / 20)))
+ */
+static const u16 scarlett2_mixer_values[SCARLETT2_MIXER_VALUE_COUNT] = {
+	0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2,
+	2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 8, 8,
+	9, 9, 10, 10, 11, 12, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
+	23, 24, 25, 27, 29, 30, 32, 34, 36, 38, 41, 43, 46, 48, 51,
+	54, 57, 61, 65, 68, 73, 77, 81, 86, 91, 97, 103, 109, 115,
+	122, 129, 137, 145, 154, 163, 173, 183, 194, 205, 217, 230,
+	244, 259, 274, 290, 307, 326, 345, 365, 387, 410, 434, 460,
+	487, 516, 547, 579, 614, 650, 689, 730, 773, 819, 867, 919,
+	973, 1031, 1092, 1157, 1225, 1298, 1375, 1456, 1543, 1634,
+	1731, 1833, 1942, 2057, 2179, 2308, 2445, 2590, 2744, 2906,
+	3078, 3261, 3454, 3659, 3876, 4105, 4349, 4606, 4879, 5168,
+	5475, 5799, 6143, 6507, 6892, 7301, 7733, 8192, 8677, 9191,
+	9736, 10313, 10924, 11571, 12257, 12983, 13752, 14567, 15430,
+	16345, 17313, 18339, 19426, 20577, 21796, 23088, 24456, 25905,
+	27440, 29066, 30788, 32612
+};
+
+/* Maximum number of analogue outputs */
+#define SCARLETT2_ANALOGUE_MAX 10
+
+/* Maximum number of various input controls */
+#define SCARLETT2_LEVEL_SWITCH_MAX 2
+#define SCARLETT2_PAD_SWITCH_MAX 8
+#define SCARLETT2_AIR_SWITCH_MAX 8
+#define SCARLETT2_DSP_SWITCH_MAX 2
+#define SCARLETT2_INPUT_MUTE_SWITCH_MAX 2
+#define SCARLETT2_PHANTOM_SWITCH_MAX 2
+#define SCARLETT2_INPUT_GAIN_MAX 2
+
+/* Maximum number of inputs to the mixer */
+#define SCARLETT2_INPUT_MIX_MAX 25
+
+/* Maximum number of outputs from the mixer */
+#define SCARLETT2_OUTPUT_MIX_MAX 12
+
+/* Maximum number of mixer gain controls */
+#define SCARLETT2_MIX_MAX (SCARLETT2_INPUT_MIX_MAX * SCARLETT2_OUTPUT_MIX_MAX)
+
+/* Maximum number of direct monitor mixer gain controls
+ * 1 (Solo) or 2 (2i2) direct monitor selections (Mono & Stereo)
+ * 2 Mix outputs (A/Left & B/Right)
+ * 4 Mix inputs
+ */
+#define SCARLETT2_MONITOR_MIX_MAX (2 * 2 * 4)
+
+/* Maximum size of the data in the USB mux assignment message:
+ * 20 inputs, 20 outputs, 25 matrix inputs, 12 spare
+ */
+#define SCARLETT2_MUX_MAX 77
+
+/* Maximum number of sources (sum of input port counts) */
+#define SCARLETT2_MAX_SRCS 52
+
+/* Maximum number of meters (sum of output port counts) */
+#define SCARLETT2_MAX_METERS 65
+
+/* Compressor parameter data
+ *
+ * The compressor parameters are 32-bit fixed point values with 24
+ * bits of fraction. Integer values are sufficient for the parameters
+ * except for ratio which we can set in 0.5:1 steps.
+ */
+struct compressor_param {
+	const char          *name;
+	snd_ctl_elem_type_t  type;
+	s32                  min;
+	s32                  max;
+	int                  scale_bits;
+};
+
+/* The available compressor parameters on the Vocaster:
+ * - Enable: Off, On
+ * - Threshold: -40dB to 0dB
+ * - Ratio: 1:1 to 50:1 in 0.5:1 steps
+ * - Knee Width: 0dB to 10dB
+ * - Attack: 30ms to 127ms
+ * - Release: 30ms to 127ms
+ * - Makeup Gain: 0dB to 24dB
+ */
+static const struct compressor_param compressor_params[] = {
+	{ "Enable",      SNDRV_CTL_ELEM_TYPE_BOOLEAN,   0,   1,  0 },
+	{ "Threshold",   SNDRV_CTL_ELEM_TYPE_INTEGER, -40,   0, 24 },
+	{ "Ratio",       SNDRV_CTL_ELEM_TYPE_INTEGER,   2, 100, 23 },
+	{ "Knee Width",  SNDRV_CTL_ELEM_TYPE_INTEGER,   0,  10, 24 },
+	{ "Attack",      SNDRV_CTL_ELEM_TYPE_INTEGER,  30, 127, 24 },
+	{ "Release",     SNDRV_CTL_ELEM_TYPE_INTEGER,  30, 127, 24 },
+	{ "Makeup Gain", SNDRV_CTL_ELEM_TYPE_INTEGER,   0,  24, 24 },
+};
+
+#define SCARLETT2_COMPRESSOR_PARAM_COUNT ARRAY_SIZE(compressor_params)
+#define SCARLETT2_COMPRESSOR_CTLS_MAX \
+	(SCARLETT2_COMPRESSOR_PARAM_COUNT * SCARLETT2_DSP_SWITCH_MAX)
+
+/* Maximum number of filter controls */
+#define SCARLETT2_PRECOMP_FLT_CTLS_MAX (2 * SCARLETT2_DSP_SWITCH_MAX)
+#define SCARLETT2_PEQ_FLT_CTLS_MAX (3 * SCARLETT2_DSP_SWITCH_MAX)
+
+/* Number of biquad filter coefficients */
+#define SCARLETT2_BIQUAD_COEFFS 5
+
+/* Maximum number of filter coefficient values */
+#define SCARLETT2_PRECOMP_FLT_VALUES_MAX \
+	(SCARLETT2_PRECOMP_FLT_CTLS_MAX * SCARLETT2_BIQUAD_COEFFS)
+#define SCARLETT2_PEQ_FLT_VALUES_MAX \
+	(SCARLETT2_PEQ_FLT_CTLS_MAX * SCARLETT2_BIQUAD_COEFFS)
+
+/* Maximum number of PEQ filter slots */
+#define SCARLETT2_PEQ_FLT_SLOTS_MAX 4
+
+/* Hardware port types:
+ * - None (no input to mux)
+ * - Analogue I/O
+ * - S/PDIF I/O
+ * - ADAT I/O
+ * - Mixer I/O
+ * - PCM I/O
+ */
+enum {
+	SCARLETT2_PORT_TYPE_NONE,
+	SCARLETT2_PORT_TYPE_ANALOGUE,
+	SCARLETT2_PORT_TYPE_SPDIF,
+	SCARLETT2_PORT_TYPE_ADAT,
+	SCARLETT2_PORT_TYPE_MIX,
+	SCARLETT2_PORT_TYPE_PCM,
+	SCARLETT2_PORT_TYPE_COUNT
+};
+
+/* I/O count of each port type kept in struct scarlett2_ports */
+enum {
+	SCARLETT2_PORT_IN,
+	SCARLETT2_PORT_OUT,
+	SCARLETT2_PORT_DIRNS
+};
+
+/* Dim/Mute buttons on the 18i20 */
+enum {
+	SCARLETT2_BUTTON_MUTE,
+	SCARLETT2_BUTTON_DIM,
+	SCARLETT2_DIM_MUTE_COUNT
+};
+
+/* Autogain target values */
+
+#define SCARLETT2_AG_TARGET_MIN (-30)
+
+enum {
+	SCARLETT2_AG_HOT_TARGET,
+	SCARLETT2_AG_MEAN_TARGET,
+	SCARLETT2_AG_PEAK_TARGET,
+	SCARLETT2_AG_TARGET_COUNT
+};
+
+/* Flash Write State */
+enum {
+	SCARLETT2_FLASH_WRITE_STATE_IDLE,
+	SCARLETT2_FLASH_WRITE_STATE_SELECTED,
+	SCARLETT2_FLASH_WRITE_STATE_ERASING,
+	SCARLETT2_FLASH_WRITE_STATE_WRITE
+};
+
+static const char *const scarlett2_dim_mute_names[SCARLETT2_DIM_MUTE_COUNT] = {
+	"Mute Playback Switch", "Dim Playback Switch"
+};
+
+/* Vocaster One speaker/headphone mute names */
+static const char *const vocaster_one_sp_hp_mute_names[] = {
+	"Speaker Mute Playback Switch",
+	"Headphones Mute Playback Switch",
+	NULL
+};
+
+/* Vocaster Two speaker/headphone mute names */
+static const char *const vocaster_two_sp_hp_mute_names[] = {
+	"Speaker Mute Playback Switch",
+	"Headphones 1 Mute Playback Switch",
+	"Headphones 2 Mute Playback Switch",
+	NULL
+};
+
+/* The autogain_status is set based on the autogain_switch and
+ * raw_autogain_status values.
+ *
+ * If autogain_switch is set, autogain_status is set to 0 (Running).
+ * The other status values are from the raw_autogain_status value + 1.
+ */
+static const char *const scarlett2_autogain_status_gen4[] = {
+	"Running",
+	"Success",
+	"SuccessDRover",
+	"WarnMinGainLimit",
+	"FailDRunder",
+	"FailMaxGainLimit",
+	"FailClipped",
+	"Cancelled",
+	"Root",
+	"Invalid",
+	NULL
+};
+
+static const char *const scarlett2_autogain_status_vocaster[] = {
+	"Running",
+	"Success",
+	"FailPG",
+	"FailRange",
+	"WarnMaxCap",
+	"WarnMinCap",
+	"Cancelled",
+	"Invalid",
+	NULL
+};
+
+/* Power Status Values */
+enum {
+	SCARLETT2_POWER_STATUS_EXT,
+	SCARLETT2_POWER_STATUS_BUS,
+	SCARLETT2_POWER_STATUS_FAIL,
+	SCARLETT2_POWER_STATUS_COUNT
+};
+
+/* Notification callback functions */
+struct scarlett2_notification {
+	u32 mask;
+	void (*func)(struct usb_mixer_interface *mixer);
+};
+
+static void scarlett2_notify_ack(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_sync(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_dim_mute(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_monitor(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_volume(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_level(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_pad(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_air(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_dsp(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_mute(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_phantom(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_other(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_select(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_gain(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_autogain(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_input_safe(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_monitor_other(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_direct_monitor(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_power_status(struct usb_mixer_interface *mixer);
+static void scarlett2_notify_pcm_input_switch(
+					struct usb_mixer_interface *mixer);
+static void scarlett2_notify_bluetooth(struct usb_mixer_interface *mixer);
+
+/* Arrays of notification callback functions */
+
+static const struct scarlett2_notification scarlett2_notifications[] = {
+	{ 0x00000001, scarlett2_notify_ack },
+	{ 0x00000008, scarlett2_notify_sync },
+	{ 0x00200000, scarlett2_notify_dim_mute },
+	{ 0x00400000, scarlett2_notify_monitor },
+	{ 0x00800000, scarlett2_notify_input_other },
+	{ 0x01000000, scarlett2_notify_monitor_other },
+	{ 0, NULL }
+};
+
+static const struct scarlett2_notification scarlett3a_notifications[] = {
+	{ 0x00000001, scarlett2_notify_ack },
+	{ 0x00800000, scarlett2_notify_input_other },
+	{ 0x01000000, scarlett2_notify_direct_monitor },
+	{ 0, NULL }
+};
+
+static const struct scarlett2_notification vocaster_notifications[] = {
+	{ 0x00000001, scarlett2_notify_ack },
+	{ 0x00000008, scarlett2_notify_sync },
+	{ 0x00200000, scarlett2_notify_input_mute },
+	{ 0x00400000, scarlett2_notify_autogain },
+	{ 0x04000000, scarlett2_notify_input_dsp },
+	{ 0x08000000, scarlett2_notify_input_gain },
+	{ 0x10000000, scarlett2_notify_input_phantom },
+	{ 0x20000000, scarlett2_notify_bluetooth },
+	{ 0, NULL }
+};
+
+static const struct scarlett2_notification scarlett4_solo_notifications[] = {
+	{ 0x00000001, scarlett2_notify_ack },
+	{ 0x00000008, scarlett2_notify_sync },
+	{ 0x00400000, scarlett2_notify_input_air },
+	{ 0x00800000, scarlett2_notify_direct_monitor },
+	{ 0x01000000, scarlett2_notify_input_level },
+	{ 0x02000000, scarlett2_notify_input_phantom },
+	{ 0x04000000, scarlett2_notify_pcm_input_switch },
+	{ 0, NULL }
+};
+
+static const struct scarlett2_notification scarlett4_2i2_notifications[] = {
+	{ 0x00000001, scarlett2_notify_ack },
+	{ 0x00000008, scarlett2_notify_sync },
+	{ 0x00200000, scarlett2_notify_input_safe },
+	{ 0x00400000, scarlett2_notify_autogain },
+	{ 0x00800000, scarlett2_notify_input_air },
+	{ 0x01000000, scarlett2_notify_direct_monitor },
+	{ 0x02000000, scarlett2_notify_input_select },
+	{ 0x04000000, scarlett2_notify_input_level },
+	{ 0x08000000, scarlett2_notify_input_phantom },
+	{ 0x10000000, NULL }, /* power status, ignored */
+	{ 0x40000000, scarlett2_notify_input_gain },
+	{ 0x80000000, NULL }, /* power status, ignored */
+	{ 0, NULL }
+};
+
+static const struct scarlett2_notification scarlett4_4i4_notifications[] = {
+	{ 0x00000001, scarlett2_notify_ack },
+	{ 0x00000008, scarlett2_notify_sync },
+	{ 0x00200000, scarlett2_notify_input_safe },
+	{ 0x00400000, scarlett2_notify_autogain },
+	{ 0x00800000, scarlett2_notify_input_air },
+	{ 0x01000000, scarlett2_notify_input_select },
+	{ 0x02000000, scarlett2_notify_input_level },
+	{ 0x04000000, scarlett2_notify_input_phantom },
+	{ 0x08000000, scarlett2_notify_power_status }, /* power external */
+	{ 0x20000000, scarlett2_notify_input_gain },
+	{ 0x40000000, scarlett2_notify_power_status }, /* power status */
+	{ 0x80000000, scarlett2_notify_volume },
+	{ 0, NULL }
+};
+
+/* Configuration parameters that can be read and written */
+enum {
+	SCARLETT2_CONFIG_DIM_MUTE,
+	SCARLETT2_CONFIG_LINE_OUT_VOLUME,
+	SCARLETT2_CONFIG_MUTE_SWITCH,
+	SCARLETT2_CONFIG_SW_HW_SWITCH,
+	SCARLETT2_CONFIG_MASTER_VOLUME,
+	SCARLETT2_CONFIG_HEADPHONE_VOLUME,
+	SCARLETT2_CONFIG_LEVEL_SWITCH,
+	SCARLETT2_CONFIG_PAD_SWITCH,
+	SCARLETT2_CONFIG_MSD_SWITCH,
+	SCARLETT2_CONFIG_AIR_SWITCH,
+	SCARLETT2_CONFIG_DSP_SWITCH,
+	SCARLETT2_CONFIG_COMPRESSOR_PARAMS,
+	SCARLETT2_CONFIG_PRECOMP_FLT_SWITCH,
+	SCARLETT2_CONFIG_PRECOMP_FLT_PARAMS,
+	SCARLETT2_CONFIG_PEQ_FLT_SWITCH,
+	SCARLETT2_CONFIG_PEQ_FLT_PARAMS,
+	SCARLETT2_CONFIG_INPUT_MUTE_SWITCH,
+	SCARLETT2_CONFIG_STANDALONE_SWITCH,
+	SCARLETT2_CONFIG_PHANTOM_SWITCH,
+	SCARLETT2_CONFIG_PHANTOM_PERSISTENCE,
+	SCARLETT2_CONFIG_DIRECT_MONITOR,
+	SCARLETT2_CONFIG_MONITOR_OTHER_SWITCH,
+	SCARLETT2_CONFIG_MONITOR_OTHER_ENABLE,
+	SCARLETT2_CONFIG_TALKBACK_MAP,
+	SCARLETT2_CONFIG_AUTOGAIN_SWITCH,
+	SCARLETT2_CONFIG_AUTOGAIN_STATUS,
+	SCARLETT2_CONFIG_AG_HOT_TARGET,
+	SCARLETT2_CONFIG_AG_MEAN_TARGET,
+	SCARLETT2_CONFIG_AG_PEAK_TARGET,
+	SCARLETT2_CONFIG_INPUT_GAIN,
+	SCARLETT2_CONFIG_SAFE_SWITCH,
+	SCARLETT2_CONFIG_INPUT_SELECT_SWITCH,
+	SCARLETT2_CONFIG_INPUT_LINK_SWITCH,
+	SCARLETT2_CONFIG_POWER_EXT,
+	SCARLETT2_CONFIG_POWER_LOW,
+	SCARLETT2_CONFIG_PCM_INPUT_SWITCH,
+	SCARLETT2_CONFIG_DIRECT_MONITOR_GAIN,
+	SCARLETT2_CONFIG_BLUETOOTH_VOLUME,
+	SCARLETT2_CONFIG_SPDIF_MODE,
+	SCARLETT2_CONFIG_SP_HP_MUTE,
+	SCARLETT2_CONFIG_FP_BRIGHTNESS,
+	SCARLETT2_CONFIG_FP_SLEEP_TIME,
+	SCARLETT2_CONFIG_COUNT
+};
+
+/* Autogain target configuration parameters and names */
+
+static const int scarlett2_ag_target_configs[] = {
+	[SCARLETT2_AG_HOT_TARGET]  = SCARLETT2_CONFIG_AG_HOT_TARGET,
+	[SCARLETT2_AG_MEAN_TARGET] = SCARLETT2_CONFIG_AG_MEAN_TARGET,
+	[SCARLETT2_AG_PEAK_TARGET] = SCARLETT2_CONFIG_AG_PEAK_TARGET
+};
+
+static const char *const scarlett2_ag_target_names[] = {
+	"Hot", "Mean", "Peak"
+};
+
+/* Location, size, and activation command number for the configuration
+ * parameters. Size is in bits and may be 1, 8, 16, or 32.
+ *
+ * Vocaster and 4th Gen devices have a parameter buffer to set certain
+ * configuration parameters. When pbuf is set, rather than writing to
+ * the given offset, the channel and value are written to the
+ * parameter buffer and the activate command is sent to the device.
+ *
+ * Some Gen 4 configuration parameters are written with 0x02 for a
+ * desired value of 0x01, and 0x03 for 0x00. These are indicated with
+ * mute set to 1. 0x02 and 0x03 are temporary values while the device
+ * makes the change and the channel and/or corresponding DSP channel
+ * output is muted.
+ */
+struct scarlett2_config {
+	u16 offset;
+	u8 size;
+	u8 activate;
+	u8 pbuf;
+	u8 mute;
+};
+
+struct scarlett2_config_set {
+	const struct scarlett2_notification *notifications;
+	u16 param_buf_addr;
+	const unsigned int *input_gain_tlv;
+	const char *const *autogain_status_texts;
+	const struct scarlett2_config items[SCARLETT2_CONFIG_COUNT];
+};
+
+/* Map firmware versions to config sets per-device.
+ *
+ * Each device lists one or more entries, sorted in ascending order of
+ * from_firmware_version. At probe time the running firmware version
+ * is looked up against this list and the last entry whose
+ * from_firmware_version is <= the running version is selected.
+ *
+ * The list is terminated by a sentinel entry with config_set == NULL.
+ */
+struct scarlett2_config_set_entry {
+	u16 from_firmware_version;
+	const struct scarlett2_config_set *config_set;
+};
+
+/* Input gain TLV dB ranges */
+
+static const DECLARE_TLV_DB_MINMAX(
+	db_scale_vocaster_gain, 0, 70 * 100
+);
+
+static const DECLARE_TLV_DB_MINMAX(
+	db_scale_gen4_gain, 0, 69 * 100
+);
+
+/* Gen 2 devices without SW/HW volume switch: 6i6, 18i8 */
+
+static const struct scarlett2_config_set scarlett2_config_set_gen2a = {
+	.notifications = scarlett2_notifications,
+	.items = {
+		[SCARLETT2_CONFIG_LINE_OUT_VOLUME] = {
+			.offset = 0x34, .size = 16, .activate = 1 },
+
+		[SCARLETT2_CONFIG_MUTE_SWITCH] = {
+			.offset = 0x5c, .size = 8, .activate = 1 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x7c, .size = 8, .activate = 7 },
+
+		[SCARLETT2_CONFIG_PAD_SWITCH] = {
+			.offset = 0x84, .size = 8, .activate = 8 },
+
+		[SCARLETT2_CONFIG_STANDALONE_SWITCH] = {
+			.offset = 0x8d, .size = 8, .activate = 6 },
+	}
+};
+
+/* Gen 2 devices with SW/HW volume switch: 18i20 */
+
+static const struct scarlett2_config_set scarlett2_config_set_gen2b = {
+	.notifications = scarlett2_notifications,
+	.items = {
+		[SCARLETT2_CONFIG_DIM_MUTE] = {
+			.offset = 0x31, .size = 8, .activate = 2 },
+
+		[SCARLETT2_CONFIG_LINE_OUT_VOLUME] = {
+			.offset = 0x34, .size = 16, .activate = 1 },
+
+		[SCARLETT2_CONFIG_MUTE_SWITCH] = {
+			.offset = 0x5c, .size = 8, .activate = 1 },
+
+		[SCARLETT2_CONFIG_SW_HW_SWITCH] = {
+			.offset = 0x66, .size = 8, .activate = 3 },
+
+		[SCARLETT2_CONFIG_MASTER_VOLUME] = {
+			.offset = 0x76, .size = 16 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x7c, .size = 8, .activate = 7 },
+
+		[SCARLETT2_CONFIG_PAD_SWITCH] = {
+			.offset = 0x84, .size = 8, .activate = 8 },
+
+		[SCARLETT2_CONFIG_STANDALONE_SWITCH] = {
+			.offset = 0x8d, .size = 8, .activate = 6 },
+	}
+};
+
+/* Gen 3 devices without a mixer (Solo and 2i2) */
+static const struct scarlett2_config_set scarlett2_config_set_gen3a = {
+	.notifications = scarlett3a_notifications,
+	.items = {
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x04, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_PHANTOM_PERSISTENCE] = {
+			.offset = 0x05, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x06, .size = 8, .activate = 3 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR] = {
+			.offset = 0x07, .size = 8, .activate = 4 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x08, .size = 1, .activate = 7 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x09, .size = 1, .activate = 8 },
+	}
+};
+
+/* Gen 3 devices without SW/HW volume switch: 4i4, 8i6 */
+static const struct scarlett2_config_set scarlett2_config_set_gen3b = {
+	.notifications = scarlett2_notifications,
+	.items = {
+		[SCARLETT2_CONFIG_LINE_OUT_VOLUME] = {
+			.offset = 0x34, .size = 16, .activate = 1 },
+
+		[SCARLETT2_CONFIG_MUTE_SWITCH] = {
+			.offset = 0x5c, .size = 8, .activate = 1 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x7c, .size = 8, .activate = 7 },
+
+		[SCARLETT2_CONFIG_PAD_SWITCH] = {
+			.offset = 0x84, .size = 8, .activate = 8 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x8c, .size = 8, .activate = 8 },
+
+		[SCARLETT2_CONFIG_STANDALONE_SWITCH] = {
+			.offset = 0x95, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x9c, .size = 1, .activate = 8 },
+
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x9d, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_PHANTOM_PERSISTENCE] = {
+			.offset = 0x9e, .size = 8, .activate = 6 },
+	}
+};
+
+/* Gen 3 devices with SW/HW volume switch: 18i8, 18i20 */
+static const struct scarlett2_config_set scarlett2_config_set_gen3c = {
+	.notifications = scarlett2_notifications,
+	.items = {
+		[SCARLETT2_CONFIG_DIM_MUTE] = {
+			.offset = 0x31, .size = 8, .activate = 2 },
+
+		[SCARLETT2_CONFIG_LINE_OUT_VOLUME] = {
+			.offset = 0x34, .size = 16, .activate = 1 },
+
+		[SCARLETT2_CONFIG_MUTE_SWITCH] = {
+			.offset = 0x5c, .size = 8, .activate = 1 },
+
+		[SCARLETT2_CONFIG_SW_HW_SWITCH] = {
+			.offset = 0x66, .size = 8, .activate = 3 },
+
+		[SCARLETT2_CONFIG_MASTER_VOLUME] = {
+			.offset = 0x76, .size = 16 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x7c, .size = 8, .activate = 7 },
+
+		[SCARLETT2_CONFIG_PAD_SWITCH] = {
+			.offset = 0x84, .size = 8, .activate = 8 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x8c, .size = 8, .activate = 8 },
+
+		[SCARLETT2_CONFIG_STANDALONE_SWITCH] = {
+			.offset = 0x95, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x9c, .size = 1, .activate = 8 },
+
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x9d, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_PHANTOM_PERSISTENCE] = {
+			.offset = 0x9e, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_MONITOR_OTHER_SWITCH] = {
+			.offset = 0x9f, .size = 1, .activate = 10 },
+
+		[SCARLETT2_CONFIG_MONITOR_OTHER_ENABLE] = {
+			.offset = 0xa0, .size = 1, .activate = 10 },
+
+		[SCARLETT2_CONFIG_TALKBACK_MAP] = {
+			.offset = 0xb0, .size = 16, .activate = 10 },
+
+		[SCARLETT2_CONFIG_SPDIF_MODE] = {
+			.offset = 0x94, .size = 8, .activate = 6 },
+	}
+};
+
+/* Vocaster */
+static const struct scarlett2_config_set scarlett2_config_set_vocaster = {
+	.notifications = vocaster_notifications,
+	.param_buf_addr = 0x1bc,
+	.input_gain_tlv = db_scale_vocaster_gain,
+	.autogain_status_texts = scarlett2_autogain_status_vocaster,
+	.items = {
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x9d, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_SWITCH] = {
+			.offset = 0x1c0, .size = 8, .activate = 19, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_STATUS] = {
+			.offset = 0x1c2, .size = 8, },
+
+		[SCARLETT2_CONFIG_AG_HOT_TARGET] = {
+			.offset = 0xc1, .size = 8, .activate = 29, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_GAIN] = {
+			.offset = 0x9f, .size = 8, .activate = 21, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x9c, .size = 1, .activate = 20, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_DSP_SWITCH] = {
+			.offset = 0x1c4, .size = 8, .activate = 22, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_COMPRESSOR_PARAMS] = {
+			.offset = 0x1c8, .size = 32, .activate = 23 },
+
+		[SCARLETT2_CONFIG_PRECOMP_FLT_SWITCH] = {
+			.offset = 0x7c, .size = 32, .activate = 27 },
+
+		[SCARLETT2_CONFIG_PRECOMP_FLT_PARAMS] = {
+			.offset = 0x200, .size = 32, .activate = 27 },
+
+		[SCARLETT2_CONFIG_PEQ_FLT_SWITCH] = {
+			.offset = 0x84, .size = 32, .activate = 27 },
+
+		[SCARLETT2_CONFIG_PEQ_FLT_PARAMS] = {
+			.offset = 0x250, .size = 32, .activate = 27 },
+
+		[SCARLETT2_CONFIG_INPUT_MUTE_SWITCH] = {
+			.offset = 0x1be, .size = 8, .activate = 17, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_BLUETOOTH_VOLUME] = {
+			.offset = 0xbf, .size = 8, .activate = 28 },
+
+		[SCARLETT2_CONFIG_SP_HP_MUTE] = {
+			.offset = 0xab, .size = 8, .activate = 10 },
+	}
+};
+
+/* Solo Gen 4 */
+static const struct scarlett2_config_set scarlett2_config_set_gen4_solo = {
+	.notifications = scarlett4_solo_notifications,
+	.param_buf_addr = 0xd8,
+	.items = {
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x47, .size = 8, .activate = 4 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR] = {
+			.offset = 0x108, .size = 8, .activate = 12, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x46, .size = 8, .activate = 9, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x3d, .size = 8, .activate = 10, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x3e, .size = 8, .activate = 11, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PCM_INPUT_SWITCH] = {
+			.offset = 0x206, .size = 8, .activate = 25, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR_GAIN] = {
+			.offset = 0x232, .size = 16, .activate = 26 }
+	}
+};
+
+/* Solo Gen 4, firmware version 2417 and above */
+static const struct scarlett2_config_set scarlett2_config_set_gen4_solo_2417 = {
+	.notifications = scarlett4_solo_notifications,
+	.param_buf_addr = 0xd8,
+	.items = {
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x47, .size = 8, .activate = 4 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR] = {
+			.offset = 0x108, .size = 8, .activate = 12, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x46, .size = 8, .activate = 9, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x3d, .size = 8, .activate = 10, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x3e, .size = 8, .activate = 11, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PCM_INPUT_SWITCH] = {
+			.offset = 0x206, .size = 8, .activate = 25, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR_GAIN] = {
+			.offset = 0x232, .size = 16, .activate = 26 },
+
+		[SCARLETT2_CONFIG_FP_BRIGHTNESS] = {
+			.offset = 0x243, .size = 8, .activate = 27, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_FP_SLEEP_TIME] = {
+			.offset = 0x248, .size = 32, .activate = 29 }
+	}
+};
+
+/* 2i2 Gen 4 */
+static const struct scarlett2_config_set scarlett2_config_set_gen4_2i2 = {
+	.notifications = scarlett4_2i2_notifications,
+	.param_buf_addr = 0xfc,
+	.input_gain_tlv = db_scale_gen4_gain,
+	.autogain_status_texts = scarlett2_autogain_status_gen4,
+	.items = {
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x49, .size = 8, .activate = 4 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR] = {
+			.offset = 0x14a, .size = 8, .activate = 16, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_SWITCH] = {
+			.offset = 0x135, .size = 8, .activate = 10, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_STATUS] = {
+			.offset = 0x137, .size = 8 },
+
+		[SCARLETT2_CONFIG_AG_MEAN_TARGET] = {
+			.offset = 0x131, .size = 8, .activate = 29, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AG_PEAK_TARGET] = {
+			.offset = 0x132, .size = 8, .activate = 30, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x48, .size = 8, .activate = 11, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_GAIN] = {
+			.offset = 0x4b, .size = 8, .activate = 12, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x3c, .size = 8, .activate = 13, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_SAFE_SWITCH] = {
+			.offset = 0x147, .size = 8, .activate = 14, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x3e, .size = 8, .activate = 15, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_SELECT_SWITCH] = {
+			.offset = 0x14b, .size = 8, .activate = 17, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_LINK_SWITCH] = {
+			.offset = 0x14e, .size = 8, .activate = 18, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR_GAIN] = {
+			.offset = 0x2a0, .size = 16, .activate = 36 }
+	}
+};
+
+/* 2i2 Gen 4, firmware version 2417 and above
+ *
+ * Firmware 2417 shifted DIRECT_MONITOR_GAIN by 4 bytes and added
+ * front-panel brightness and sleep controls; all other offsets are
+ * unchanged from scarlett2_config_set_gen4_2i2.
+ */
+static const struct scarlett2_config_set scarlett2_config_set_gen4_2i2_2417 = {
+	.notifications = scarlett4_2i2_notifications,
+	.param_buf_addr = 0xfc,
+	.input_gain_tlv = db_scale_gen4_gain,
+	.autogain_status_texts = scarlett2_autogain_status_gen4,
+	.items = {
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x49, .size = 8, .activate = 4 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR] = {
+			.offset = 0x14a, .size = 8, .activate = 16, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_SWITCH] = {
+			.offset = 0x135, .size = 8, .activate = 10, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_STATUS] = {
+			.offset = 0x137, .size = 8 },
+
+		[SCARLETT2_CONFIG_AG_MEAN_TARGET] = {
+			.offset = 0x131, .size = 8, .activate = 29, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AG_PEAK_TARGET] = {
+			.offset = 0x132, .size = 8, .activate = 30, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x48, .size = 8, .activate = 11, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_GAIN] = {
+			.offset = 0x4b, .size = 8, .activate = 12, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x3c, .size = 8, .activate = 13, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_SAFE_SWITCH] = {
+			.offset = 0x147, .size = 8, .activate = 14, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x3e, .size = 8, .activate = 15, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_SELECT_SWITCH] = {
+			.offset = 0x14b, .size = 8, .activate = 17, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_LINK_SWITCH] = {
+			.offset = 0x14e, .size = 8, .activate = 18, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_DIRECT_MONITOR_GAIN] = {
+			.offset = 0x2a4, .size = 16, .activate = 36 },
+
+		[SCARLETT2_CONFIG_FP_BRIGHTNESS] = {
+			.offset = 0x2c7, .size = 8, .activate = 37, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_FP_SLEEP_TIME] = {
+			.offset = 0x2cc, .size = 32, .activate = 39 }
+	}
+};
+
+/* 4i4 Gen 4 */
+static const struct scarlett2_config_set scarlett2_config_set_gen4_4i4 = {
+	.notifications = scarlett4_4i4_notifications,
+	.param_buf_addr = 0x130,
+	.input_gain_tlv = db_scale_gen4_gain,
+	.autogain_status_texts = scarlett2_autogain_status_gen4,
+	.items = {
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x5c, .size = 8, .activate = 4 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_SWITCH] = {
+			.offset = 0x13e, .size = 8, .activate = 10, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_STATUS] = {
+			.offset = 0x140, .size = 8 },
+
+		[SCARLETT2_CONFIG_AG_MEAN_TARGET] = {
+			.offset = 0x13a, .size = 8, .activate = 23, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AG_PEAK_TARGET] = {
+			.offset = 0x13b, .size = 8, .activate = 24, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x5a, .size = 8, .activate = 11, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_GAIN] = {
+			.offset = 0x5e, .size = 8, .activate = 12, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x4e, .size = 8, .activate = 13, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_SAFE_SWITCH] = {
+			.offset = 0x150, .size = 8, .activate = 14, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x50, .size = 8, .activate = 15, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_SELECT_SWITCH] = {
+			.offset = 0x153, .size = 8, .activate = 16, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_LINK_SWITCH] = {
+			.offset = 0x156, .size = 8, .activate = 17, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_MASTER_VOLUME] = {
+			.offset = 0x32, .size = 16 },
+
+		[SCARLETT2_CONFIG_HEADPHONE_VOLUME] = {
+			.offset = 0x3a, .size = 16 },
+
+		[SCARLETT2_CONFIG_POWER_EXT] = {
+			.offset = 0x168, .size = 8 },
+
+		[SCARLETT2_CONFIG_POWER_LOW] = {
+			.offset = 0x16d, .size = 8 }
+	}
+};
+
+/* 4i4 Gen 4, firmware version 2417 and above */
+static const struct scarlett2_config_set scarlett2_config_set_gen4_4i4_2417 = {
+	.notifications = scarlett4_4i4_notifications,
+	.param_buf_addr = 0x130,
+	.input_gain_tlv = db_scale_gen4_gain,
+	.autogain_status_texts = scarlett2_autogain_status_gen4,
+	.items = {
+		[SCARLETT2_CONFIG_MSD_SWITCH] = {
+			.offset = 0x5c, .size = 8, .activate = 4 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_SWITCH] = {
+			.offset = 0x13e, .size = 8, .activate = 10, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AUTOGAIN_STATUS] = {
+			.offset = 0x140, .size = 8 },
+
+		[SCARLETT2_CONFIG_AG_MEAN_TARGET] = {
+			.offset = 0x13a, .size = 8, .activate = 23, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AG_PEAK_TARGET] = {
+			.offset = 0x13b, .size = 8, .activate = 24, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_PHANTOM_SWITCH] = {
+			.offset = 0x5a, .size = 8, .activate = 11, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_GAIN] = {
+			.offset = 0x5e, .size = 8, .activate = 12, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x4e, .size = 8, .activate = 13, .pbuf = 1,
+			.mute = 1 },
+
+		[SCARLETT2_CONFIG_SAFE_SWITCH] = {
+			.offset = 0x150, .size = 8, .activate = 14, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x50, .size = 8, .activate = 15, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_SELECT_SWITCH] = {
+			.offset = 0x153, .size = 8, .activate = 16, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_INPUT_LINK_SWITCH] = {
+			.offset = 0x156, .size = 8, .activate = 17, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_MASTER_VOLUME] = {
+			.offset = 0x32, .size = 16 },
+
+		[SCARLETT2_CONFIG_HEADPHONE_VOLUME] = {
+			.offset = 0x3a, .size = 16 },
+
+		[SCARLETT2_CONFIG_POWER_EXT] = {
+			.offset = 0x168, .size = 8 },
+
+		[SCARLETT2_CONFIG_POWER_LOW] = {
+			.offset = 0x16d, .size = 8 },
+
+		[SCARLETT2_CONFIG_FP_BRIGHTNESS] = {
+			.offset = 0x3a9, .size = 8, .activate = 36, .pbuf = 1 },
+
+		[SCARLETT2_CONFIG_FP_SLEEP_TIME] = {
+			.offset = 0x3ac, .size = 32, .activate = 38 }
+	}
+};
+
+/* Clarett USB and Clarett+ devices: 2Pre, 4Pre, 8Pre */
+static const struct scarlett2_config_set scarlett2_config_set_clarett = {
+	.notifications = scarlett2_notifications,
+	.items = {
+		[SCARLETT2_CONFIG_DIM_MUTE] = {
+			.offset = 0x31, .size = 8, .activate = 2 },
+
+		[SCARLETT2_CONFIG_LINE_OUT_VOLUME] = {
+			.offset = 0x34, .size = 16, .activate = 1 },
+
+		[SCARLETT2_CONFIG_MUTE_SWITCH] = {
+			.offset = 0x5c, .size = 8, .activate = 1 },
+
+		[SCARLETT2_CONFIG_SW_HW_SWITCH] = {
+			.offset = 0x66, .size = 8, .activate = 3 },
+
+		[SCARLETT2_CONFIG_MASTER_VOLUME] = {
+			.offset = 0x76, .size = 16 },
+
+		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+			.offset = 0x7c, .size = 8, .activate = 7 },
+
+		[SCARLETT2_CONFIG_AIR_SWITCH] = {
+			.offset = 0x95, .size = 8, .activate = 8 },
+
+		[SCARLETT2_CONFIG_STANDALONE_SWITCH] = {
+			.offset = 0x8d, .size = 8, .activate = 6 },
+
+		[SCARLETT2_CONFIG_SPDIF_MODE] = {
+			.offset = 0x9e, .size = 8, .activate = 4 },
+	}
+};
+
+/* Description of each hardware port type:
+ * - id: hardware ID of this port type
+ * - src_descr: printf format string for mux input selections
+ * - src_num_offset: added to channel number for the fprintf
+ * - dst_descr: printf format string for mixer controls
+ */
+struct scarlett2_port {
+	u16 id;
+	const char * const src_descr;
+	int src_num_offset;
+	const char * const dst_descr;
+	const char * const dsp_src_descr;
+	const char * const dsp_dst_descr;
+};
+
+static const struct scarlett2_port scarlett2_ports[SCARLETT2_PORT_TYPE_COUNT] = {
+	[SCARLETT2_PORT_TYPE_NONE] = {
+		.id = 0x000,
+		.src_descr = "Off"
+	},
+	[SCARLETT2_PORT_TYPE_ANALOGUE] = {
+		.id = 0x080,
+		.src_descr = "Analogue %d",
+		.src_num_offset = 1,
+		.dst_descr = "Analogue Output %02d Playback"
+	},
+	[SCARLETT2_PORT_TYPE_SPDIF] = {
+		.id = 0x180,
+		.src_descr = "S/PDIF %d",
+		.src_num_offset = 1,
+		.dst_descr = "S/PDIF Output %d Playback"
+	},
+	[SCARLETT2_PORT_TYPE_ADAT] = {
+		.id = 0x200,
+		.src_descr = "ADAT %d",
+		.src_num_offset = 1,
+		.dst_descr = "ADAT Output %d Playback"
+	},
+	[SCARLETT2_PORT_TYPE_MIX] = {
+		.id = 0x300,
+		.src_descr = "Mix %c",
+		.src_num_offset = 'A',
+		.dst_descr = "Mixer Input %02d Capture",
+		.dsp_src_descr = "DSP %d",
+		.dsp_dst_descr = "DSP Input %d Capture"
+	},
+	[SCARLETT2_PORT_TYPE_PCM] = {
+		.id = 0x600,
+		.src_descr = "PCM %d",
+		.src_num_offset = 1,
+		.dst_descr = "PCM %02d Capture"
+	},
+};
+
+/* Number of mux tables: one for each band of sample rates
+ * (44.1/48kHz, 88.2/96kHz, and 176.4/176kHz)
+ */
+#define SCARLETT2_MUX_TABLES 3
+
+/* Maximum number of entries in a mux table */
+#define SCARLETT2_MAX_MUX_ENTRIES 10
+
+/* One entry within mux_assignment defines the port type and range of
+ * ports to add to the set_mux message. The end of the list is marked
+ * with count == 0.
+ */
+struct scarlett2_mux_entry {
+	u8 port_type;
+	u8 start;
+	u8 count;
+};
+
+/* Maximum number of entries in a mux table */
+#define SCARLETT2_MAX_METER_ENTRIES 9
+
+/* One entry within meter_assignment defines the range of mux outputs
+ * that consecutive meter entries are mapped to. The end of the list
+ * is marked with count == 0.
+ */
+struct scarlett2_meter_entry {
+	u8 start;
+	u8 count;
+};
+
+struct scarlett2_device_info {
+	/* which sets of configuration parameters the device uses */
+	const struct scarlett2_config_set_entry *config_sets;
+
+	/* has a downloadable device map */
+	u8 has_devmap;
+
+	/* support for main/alt speaker switching */
+	u8 has_speaker_switching;
+
+	/* support for talkback microphone */
+	u8 has_talkback;
+
+	/* the number of analogue inputs with a software switchable
+	 * level control that can be set to line or instrument
+	 */
+	u8 level_input_count;
+
+	/* the first input with a level control (0-based) */
+	u8 level_input_first;
+
+	/* the number of analogue inputs with a software switchable
+	 * 10dB pad control
+	 */
+	u8 pad_input_count;
+
+	/* the number of analogue inputs with a software switchable
+	 * "air" control
+	 */
+	u8 air_input_count;
+
+	/* the first input with an air control (0-based) */
+	u8 air_input_first;
+
+	/* number of additional air options
+	 * 0 for air presence only (Gen 3)
+	 * 1 for air presence+drive (Gen 4)
+	 */
+	u8 air_option;
+
+	/* the number of analogue inputs with DSP control */
+	u8 dsp_input_count;
+
+	/* number of pre-compressor filters */
+	u8 precomp_flt_count;
+
+	/* number of parametric EQ filters */
+	u8 peq_flt_count;
+
+	/* number of PEQ filters plus unused slots */
+	u8 peq_flt_total_count;
+
+	/* the number of analogue inputs with a software switchable
+	 * mute control
+	 */
+	u8 mute_input_count;
+
+	/* the number of phantom (48V) software switchable controls */
+	u8 phantom_count;
+
+	/* the first input with phantom power control (0-based) */
+	u8 phantom_first;
+
+	/* the number of inputs each phantom switch controls */
+	u8 inputs_per_phantom;
+
+	/* the number of inputs with software-controllable gain */
+	u8 gain_input_count;
+
+	/* the number of inputs with safe mode */
+	u8 safe_input_count;
+
+	/* the number of direct monitor options
+	 * (0 = none, 1 = mono only, 2 = mono/stereo)
+	 */
+	u8 direct_monitor;
+
+	/* the number of DSP channels */
+	u8 dsp_count;
+
+	/* has a Bluetooth module with volume control */
+	u8 has_bluetooth;
+
+	/* S/PDIF Source/Digital I/O mode control */
+	const char * const spdif_mode_control_name;
+	const u8 *spdif_mode_values;
+	const char * const *spdif_mode_texts;
+
+	/* remap analogue outputs; 18i8 Gen 3 has "line 3/4" connected
+	 * internally to the analogue 7/8 outputs
+	 */
+	u8 line_out_remap_enable;
+	u8 line_out_remap[SCARLETT2_ANALOGUE_MAX];
+	u8 line_out_unmap[SCARLETT2_ANALOGUE_MAX];
+
+	/* additional description for the line out volume controls */
+	const char * const line_out_descrs[SCARLETT2_ANALOGUE_MAX];
+
+	/* Vocaster speaker/headphone mute control names */
+	const char * const *sp_hp_mute_names;
+
+	/* number of sources/destinations of each port type */
+	const int port_count[SCARLETT2_PORT_TYPE_COUNT][SCARLETT2_PORT_DIRNS];
+
+	/* layout/order of the entries in the set_mux message */
+	struct scarlett2_mux_entry mux_assignment[SCARLETT2_MUX_TABLES]
+						 [SCARLETT2_MAX_MUX_ENTRIES];
+
+	/* map from meter level order returned by
+	 * SCARLETT2_USB_GET_METER to index into mux[] entries (same
+	 * as the order returned by scarlett2_meter_ctl_get())
+	 */
+	struct scarlett2_meter_entry meter_map[SCARLETT2_MAX_METER_ENTRIES];
+};
+
+struct scarlett2_data {
+	struct usb_mixer_interface *mixer;
+	struct mutex usb_mutex; /* prevent sending concurrent USB requests */
+	struct completion cmd_done;
+	struct urb *urb;        /* notification endpoint */
+	struct mutex data_mutex; /* lock access to this data */
+	u8 running;
+	u8 hwdep_in_use;
+	u8 selected_flash_segment_id;
+	u8 flash_write_state;
+	struct delayed_work work;
+	const struct scarlett2_device_info *info;
+	const struct scarlett2_config_set *config_set;
+	const char *series_name;
+	__u8 bInterfaceNumber;
+	__u8 bEndpointAddress;
+	__u16 wMaxPacketSize;
+	__u8 bInterval;
+	u8 num_mux_srcs;
+	u8 num_mux_dsts;
+	u8 num_mix_in;
+	u8 num_mix_out;
+	u8 num_line_out;
+	u8 num_monitor_mix_ctls;
+	u8 num_autogain_status_texts;
+	u32 firmware_version;
+	u8 flash_segment_nums[SCARLETT2_SEGMENT_ID_COUNT];
+	u8 flash_segment_blocks[SCARLETT2_SEGMENT_ID_COUNT];
+	u16 scarlett2_seq;
+	u8 sync_updated;
+	u8 vol_updated;
+	u8 dim_mute_updated;
+	u8 input_level_updated;
+	u8 input_pad_updated;
+	u8 input_air_updated;
+	u8 input_dsp_updated;
+	u8 input_mute_updated;
+	u8 input_phantom_updated;
+	u8 input_select_updated;
+	u8 input_gain_updated;
+	u8 autogain_updated;
+	u8 input_safe_updated;
+	u8 pcm_input_switch_updated;
+	u8 monitor_other_updated;
+	u8 direct_monitor_updated;
+	u8 mux_updated;
+	u8 mix_updated;
+	u8 speaker_switching_switched;
+	u8 power_status_updated;
+	u8 bluetooth_updated;
+	u8 sync;
+	u8 master_vol;
+	u8 headphone_vol;
+	u8 vol[SCARLETT2_ANALOGUE_MAX];
+	u8 vol_sw_hw_switch[SCARLETT2_ANALOGUE_MAX];
+	u8 mute_switch[SCARLETT2_ANALOGUE_MAX];
+	u8 level_switch[SCARLETT2_LEVEL_SWITCH_MAX];
+	u8 pad_switch[SCARLETT2_PAD_SWITCH_MAX];
+	u8 dim_mute[SCARLETT2_DIM_MUTE_COUNT];
+	u8 sp_hp_mute;
+	u8 air_switch[SCARLETT2_AIR_SWITCH_MAX];
+	u8 dsp_switch[SCARLETT2_DSP_SWITCH_MAX];
+	s32 compressor_values[SCARLETT2_COMPRESSOR_CTLS_MAX];
+	s32 precomp_flt_values[SCARLETT2_PRECOMP_FLT_VALUES_MAX];
+	s32 peq_flt_values[SCARLETT2_PEQ_FLT_VALUES_MAX];
+	u8 precomp_flt_switch[SCARLETT2_DSP_SWITCH_MAX];
+	u8 peq_flt_switch[SCARLETT2_DSP_SWITCH_MAX];
+	u8 input_mute_switch[SCARLETT2_INPUT_MUTE_SWITCH_MAX];
+	u8 phantom_switch[SCARLETT2_PHANTOM_SWITCH_MAX];
+	u8 phantom_persistence;
+	u8 input_select_switch;
+	u8 input_link_switch[SCARLETT2_INPUT_GAIN_MAX];
+	u8 gain[SCARLETT2_INPUT_GAIN_MAX];
+	u8 autogain_switch[SCARLETT2_INPUT_GAIN_MAX];
+	u8 autogain_status[SCARLETT2_INPUT_GAIN_MAX];
+	s8 ag_targets[SCARLETT2_AG_TARGET_COUNT];
+	u8 safe_switch[SCARLETT2_INPUT_GAIN_MAX];
+	u8 pcm_input_switch;
+	u8 direct_monitor_switch;
+	u8 speaker_switching_switch;
+	u8 talkback_switch;
+	u8 talkback_map[SCARLETT2_OUTPUT_MIX_MAX];
+	u8 msd_switch;
+	u8 standalone_switch;
+	u8 power_status;
+	u8 bluetooth_volume;
+	u8 spdif_mode;
+	u8 meter_level_map[SCARLETT2_MAX_METERS];
+	struct snd_kcontrol *sync_ctl;
+	struct snd_kcontrol *master_vol_ctl;
+	struct snd_kcontrol *headphone_vol_ctl;
+	struct snd_kcontrol *vol_ctls[SCARLETT2_ANALOGUE_MAX];
+	struct snd_kcontrol *sw_hw_ctls[SCARLETT2_ANALOGUE_MAX];
+	struct snd_kcontrol *mute_ctls[SCARLETT2_ANALOGUE_MAX];
+	struct snd_kcontrol *dim_mute_ctls[SCARLETT2_DIM_MUTE_COUNT];
+	struct snd_kcontrol *level_ctls[SCARLETT2_LEVEL_SWITCH_MAX];
+	struct snd_kcontrol *pad_ctls[SCARLETT2_PAD_SWITCH_MAX];
+	struct snd_kcontrol *air_ctls[SCARLETT2_AIR_SWITCH_MAX];
+	struct snd_kcontrol *dsp_ctls[SCARLETT2_DSP_SWITCH_MAX];
+	struct snd_kcontrol *input_mute_ctls[SCARLETT2_INPUT_MUTE_SWITCH_MAX];
+	struct snd_kcontrol *phantom_ctls[SCARLETT2_PHANTOM_SWITCH_MAX];
+	struct snd_kcontrol *input_select_ctl;
+	struct snd_kcontrol *input_link_ctls[SCARLETT2_INPUT_GAIN_MAX];
+	struct snd_kcontrol *input_gain_ctls[SCARLETT2_INPUT_GAIN_MAX];
+	struct snd_kcontrol *autogain_ctls[SCARLETT2_INPUT_GAIN_MAX];
+	struct snd_kcontrol *autogain_status_ctls[SCARLETT2_INPUT_GAIN_MAX];
+	struct snd_kcontrol *ag_target_ctls[SCARLETT2_AG_TARGET_COUNT];
+	struct snd_kcontrol *safe_ctls[SCARLETT2_INPUT_GAIN_MAX];
+	struct snd_kcontrol *pcm_input_switch_ctl;
+	struct snd_kcontrol *mux_ctls[SCARLETT2_MUX_MAX];
+	struct snd_kcontrol *mix_ctls[SCARLETT2_MIX_MAX];
+	struct snd_kcontrol *compressor_ctls[SCARLETT2_COMPRESSOR_CTLS_MAX];
+	struct snd_kcontrol *precomp_flt_switch_ctls[SCARLETT2_DSP_SWITCH_MAX];
+	struct snd_kcontrol *peq_flt_switch_ctls[SCARLETT2_DSP_SWITCH_MAX];
+	struct snd_kcontrol *direct_monitor_ctl;
+	struct snd_kcontrol *speaker_switching_ctl;
+	struct snd_kcontrol *talkback_ctl;
+	struct snd_kcontrol *power_status_ctl;
+	struct snd_kcontrol *bluetooth_volume_ctl;
+	u8 fp_brightness;
+	u32 fp_sleep_time;
+	u8 mux[SCARLETT2_MUX_MAX];
+	u8 mix[SCARLETT2_MIX_MAX];
+	u8 monitor_mix[SCARLETT2_MONITOR_MIX_MAX];
+};
+
+/*** Model-specific data ***/
+
+static const struct scarlett2_device_info s6i6_gen2_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen2a },
+		{ }
+	},
+	.level_input_count = 2,
+	.pad_input_count = 2,
+
+	.line_out_descrs = {
+		"Headphones 1 L",
+		"Headphones 1 R",
+		"Headphones 2 L",
+		"Headphones 2 R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  4,  4 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+		[SCARLETT2_PORT_TYPE_PCM]      = {  6,  6 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	} },
+
+	.meter_map = {
+		{ 24,  6 },
+		{  0, 24 },
+		{  0,  0 },
+	}
+};
+
+static const struct scarlett2_device_info s18i8_gen2_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen2a },
+		{ }
+	},
+	.level_input_count = 2,
+	.pad_input_count = 4,
+
+	.line_out_descrs = {
+		"Monitor L",
+		"Monitor R",
+		"Headphones 1 L",
+		"Headphones 1 R",
+		"Headphones 2 L",
+		"Headphones 2 R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  8,  6 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+		[SCARLETT2_PORT_TYPE_ADAT]     = {  8,  0 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+		[SCARLETT2_PORT_TYPE_PCM]      = {  8, 18 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 14 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  4 },
+		{ 0,                            0,  0 },
+	} },
+
+	.meter_map = {
+		{ 26, 18 },
+		{  0, 26 },
+		{  0,  0 },
+	}
+};
+
+static const struct scarlett2_device_info s18i20_gen2_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen2b },
+		{ }
+	},
+
+	.line_out_descrs = {
+		"Monitor L",
+		"Monitor R",
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		"Headphones 1 L",
+		"Headphones 1 R",
+		"Headphones 2 L",
+		"Headphones 2 R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  8, 10 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+		[SCARLETT2_PORT_TYPE_ADAT]     = {  8,  8 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 20, 18 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_ADAT,     0,  8 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 14 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_ADAT,     0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  6 },
+		{ 0,                            0,  0 },
+	} },
+
+	.meter_map = {
+		{ 38, 18 },
+		{  0, 38 },
+		{  0,  0 },
+	}
+};
+
+static const struct scarlett2_device_info solo_gen3_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen3a },
+		{ }
+	},
+	.level_input_count = 1,
+	.level_input_first = 1,
+	.air_input_count = 1,
+	.phantom_count = 1,
+	.inputs_per_phantom = 1,
+	.direct_monitor = 1,
+};
+
+static const struct scarlett2_device_info s2i2_gen3_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen3a },
+		{ }
+	},
+	.level_input_count = 2,
+	.air_input_count = 2,
+	.phantom_count = 1,
+	.inputs_per_phantom = 2,
+	.direct_monitor = 2,
+};
+
+static const struct scarlett2_device_info s4i4_gen3_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen3b },
+		{ }
+	},
+	.level_input_count = 2,
+	.pad_input_count = 2,
+	.air_input_count = 2,
+	.phantom_count = 1,
+	.inputs_per_phantom = 2,
+
+	.line_out_descrs = {
+		"Monitor L",
+		"Monitor R",
+		"Headphones L",
+		"Headphones R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = { 1, 0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = { 4, 4 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 6, 8 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 4, 6 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 16 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 16 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 16 },
+		{ 0,                            0,  0 },
+	} },
+
+	.meter_map = {
+		{ 12,  6 },
+		{  0, 12 },
+		{  0,  0 },
+	}
+};
+
+static const struct scarlett2_device_info s8i6_gen3_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen3b },
+		{ }
+	},
+	.level_input_count = 2,
+	.pad_input_count = 2,
+	.air_input_count = 2,
+	.phantom_count = 1,
+	.inputs_per_phantom = 2,
+
+	.line_out_descrs = {
+		"Headphones 1 L",
+		"Headphones 1 R",
+		"Headphones 2 L",
+		"Headphones 2 R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = { 1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = { 6,  4 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = { 2,  2 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 8,  8 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 6, 10 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,      8,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 18 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,      8,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 18 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,      8,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 18 },
+		{ 0,                            0,  0 },
+	} },
+
+	.meter_map = {
+		{ 14, 8 },
+		{  0, 6 },
+		{ 22, 2 },
+		{  6, 8 },
+		{  0, 0 },
+	}
+};
+
+static const u8 scarlett2_spdif_s18i8_gen3_values[] = { 0, 2, 0xff };
+
+static const char * const scarlett2_spdif_s18i8_gen3_texts[] = {
+	"RCA",
+	"Optical",
+	NULL
+};
+
+static const struct scarlett2_device_info s18i8_gen3_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen3c },
+		{ }
+	},
+	.has_speaker_switching = 1,
+	.level_input_count = 2,
+	.pad_input_count = 4,
+	.air_input_count = 4,
+	.phantom_count = 2,
+	.inputs_per_phantom = 2,
+
+	.spdif_mode_control_name = "S/PDIF Mode Capture Enum",
+	.spdif_mode_values = scarlett2_spdif_s18i8_gen3_values,
+	.spdif_mode_texts = scarlett2_spdif_s18i8_gen3_texts,
+
+	.line_out_remap_enable = 1,
+	.line_out_remap = { 0, 1, 6, 7, 2, 3, 4, 5 },
+	.line_out_unmap = { 0, 1, 4, 5, 6, 7, 2, 3 },
+
+	.line_out_descrs = {
+		"Monitor L",
+		"Monitor R",
+		"Alt Monitor L",
+		"Alt Monitor R",
+		"Headphones 1 L",
+		"Headphones 1 R",
+		"Headphones 2 L",
+		"Headphones 2 R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  8,  8 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+		[SCARLETT2_PORT_TYPE_ADAT]     = {  8,  0 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 10, 20 },
+		[SCARLETT2_PORT_TYPE_PCM]      = {  8, 20 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,       0, 10 },
+		{ SCARLETT2_PORT_TYPE_PCM,      12,  8 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  6,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  2,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,      10,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 20 },
+		{ SCARLETT2_PORT_TYPE_NONE,      0, 10 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,       0, 10 },
+		{ SCARLETT2_PORT_TYPE_PCM,      12,  4 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  6,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  2,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,      10,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 20 },
+		{ SCARLETT2_PORT_TYPE_NONE,      0, 10 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,       0, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  6,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  2,  4 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 20 },
+		{ SCARLETT2_PORT_TYPE_NONE,      0, 10 },
+		{ 0,                             0,  0 },
+	} },
+
+	.meter_map = {
+		{ 30, 10 },
+		{ 42,  8 },
+		{  0,  2 },
+		{  6,  2 },
+		{  2,  4 },
+		{  8,  2 },
+		{ 40,  2 },
+		{ 10, 20 },
+		{  0,  0 }
+	}
+};
+
+static const u8 scarlett2_spdif_s18i20_gen3_values[] = { 0, 6, 1, 0xff };
+
+static const char * const scarlett2_spdif_s18i20_gen3_texts[] = {
+	"S/PDIF RCA",
+	"S/PDIF Optical",
+	"Dual ADAT",
+	NULL
+};
+
+static const struct scarlett2_device_info s18i20_gen3_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_gen3c },
+		{ }
+	},
+	.has_speaker_switching = 1,
+	.has_talkback = 1,
+	.level_input_count = 2,
+	.pad_input_count = 8,
+	.air_input_count = 8,
+	.phantom_count = 2,
+	.inputs_per_phantom = 4,
+
+	.spdif_mode_control_name = "Digital I/O Mode Capture Enum",
+	.spdif_mode_values = scarlett2_spdif_s18i20_gen3_values,
+	.spdif_mode_texts = scarlett2_spdif_s18i20_gen3_texts,
+
+	.line_out_descrs = {
+		"Monitor 1 L",
+		"Monitor 1 R",
+		"Monitor 2 L",
+		"Monitor 2 R",
+		NULL,
+		NULL,
+		"Headphones 1 L",
+		"Headphones 1 R",
+		"Headphones 2 L",
+		"Headphones 2 R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  9, 10 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+		[SCARLETT2_PORT_TYPE_ADAT]     = {  8,  8 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 12, 25 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 20, 20 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  8 },
+		{ SCARLETT2_PORT_TYPE_PCM,      10, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+		{ SCARLETT2_PORT_TYPE_ADAT,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_PCM,       8,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 25 },
+		{ SCARLETT2_PORT_TYPE_NONE,      0, 12 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  8 },
+		{ SCARLETT2_PORT_TYPE_PCM,      10,  8 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+		{ SCARLETT2_PORT_TYPE_ADAT,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_PCM,       8,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 25 },
+		{ SCARLETT2_PORT_TYPE_NONE,      0, 10 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,       0, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+		{ SCARLETT2_PORT_TYPE_NONE,      0, 24 },
+		{ 0,                             0,  0 },
+	} },
+
+	.meter_map = {
+		{ 45,  8 },
+		{ 55, 10 },
+		{  0, 20 },
+		{ 53,  2 },
+		{ 20, 25 },
+		{  0,  0 },
+	}
+};
+
+static const struct scarlett2_device_info vocaster_one_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 1769, &scarlett2_config_set_vocaster },
+		{ }
+	},
+	.has_devmap = 1,
+
+	.phantom_count = 1,
+	.inputs_per_phantom = 1,
+	.dsp_count = 1,
+	.dsp_input_count = 1,
+	.precomp_flt_count = 2,
+	.peq_flt_count = 3,
+	.peq_flt_total_count = 4,
+	.mute_input_count = 1,
+	.gain_input_count = 1,
+	.sp_hp_mute_names = vocaster_one_sp_hp_mute_names,
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = { 1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = { 2,  4 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 9,  9 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 4, 10 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_MIX,      8, 1 },
+		{ SCARLETT2_PORT_TYPE_PCM,      5, 5 },
+		{ SCARLETT2_PORT_TYPE_MIX,      6, 2 },
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 5 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 6 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0, 4 },
+		{ 0, 0, 0 },
+	} },
+
+	.meter_map = {
+		{ 12, 1 },
+		{ 18, 5 },
+		{ 10, 2 },
+		{ 13, 5 },
+		{  4, 6 },
+		{  0, 4 },
+		{  0, 0 }
+	}
+};
+
+static const struct scarlett2_device_info vocaster_two_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 1769, &scarlett2_config_set_vocaster },
+		{ }
+	},
+	.has_devmap = 1,
+
+	.phantom_count = 2,
+	.inputs_per_phantom = 1,
+	.dsp_count = 2,
+	.dsp_input_count = 2,
+	.precomp_flt_count = 2,
+	.peq_flt_count = 3,
+	.peq_flt_total_count = 4,
+	.mute_input_count = 2,
+	.gain_input_count = 2,
+	.has_bluetooth = 1,
+	.sp_hp_mute_names = vocaster_two_sp_hp_mute_names,
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  6,  6 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 12, 14 },
+		[SCARLETT2_PORT_TYPE_PCM]      = {  4, 14 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_MIX,      12,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       6,  8 },
+		{ SCARLETT2_PORT_TYPE_MIX,      10,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  6 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  6 },
+		{ 0, 0, 0 },
+	} },
+
+	.meter_map = {
+		{ 18,  2 },
+		{ 26,  8 },
+		{ 16,  2 },
+		{ 20,  6 },
+		{  6, 10 },
+		{  0,  6 },
+		{  0,  0 }
+	}
+};
+
+static const struct scarlett2_device_info solo_gen4_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 2115, &scarlett2_config_set_gen4_solo },
+		{ 2417, &scarlett2_config_set_gen4_solo_2417 },
+		{ }
+	},
+	.has_devmap = 1,
+
+	.level_input_count = 1,
+	.air_input_count = 1,
+	.air_input_first = 1,
+	.air_option = 1,
+	.phantom_count = 1,
+	.phantom_first = 1,
+	.inputs_per_phantom = 1,
+	.direct_monitor = 1,
+	.dsp_count = 2,
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = { 1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = { 2,  2 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 8,  6 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 2,  4 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_MIX,       4,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       2,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_MIX,       4,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       2,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_MIX,       4,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       2,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ 0,                             0,  0 },
+	} },
+
+	.meter_map = {
+		{  6,  2 },
+		{  4,  2 },
+		{  8,  4 },
+		{  2,  2 },
+		{  0,  2 },
+		{  0,  0 }
+	}
+};
+
+static const struct scarlett2_device_info s2i2_gen4_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 2115, &scarlett2_config_set_gen4_2i2 },
+		{ 2417, &scarlett2_config_set_gen4_2i2_2417 },
+		{ }
+	},
+	.has_devmap = 1,
+
+	.level_input_count = 2,
+	.air_input_count = 2,
+	.air_option = 1,
+	.phantom_count = 1,
+	.inputs_per_phantom = 2,
+	.gain_input_count = 2,
+	.safe_input_count = 2,
+	.direct_monitor = 2,
+	.dsp_count = 2,
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = { 1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = { 2,  2 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 6,  6 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 2,  4 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_MIX,       4,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       2,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_MIX,       4,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       2,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_MIX,       4,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,       2,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+		{ 0,                             0,  0 },
+	} },
+
+	.meter_map = {
+		{  6,  2 },
+		{  4,  2 },
+		{  8,  4 },
+		{  2,  2 },
+		{  0,  2 },
+		{  0,  0 }
+	}
+};
+
+static const struct scarlett2_device_info s4i4_gen4_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 2089, &scarlett2_config_set_gen4_4i4 },
+		{ 2417, &scarlett2_config_set_gen4_4i4_2417 },
+		{ }
+	},
+	.has_devmap = 1,
+
+	.level_input_count = 2,
+	.air_input_count = 2,
+	.air_option = 1,
+	.phantom_count = 2,
+	.inputs_per_phantom = 1,
+	.gain_input_count = 2,
+	.safe_input_count = 2,
+	.dsp_count = 2,
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = { 1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = { 4,  6 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 8, 12 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 6,  6 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_MIX,      10,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  6 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  6 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_MIX,      10,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  6 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  6 },
+		{ 0,                             0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_MIX,      10,  2 },
+		{ SCARLETT2_PORT_TYPE_PCM,       0,  6 },
+		{ SCARLETT2_PORT_TYPE_MIX,       0, 10 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE,  0,  6 },
+		{ 0,                             0,  0 },
+	} },
+
+	.meter_map = {
+		{ 16,  8 },
+		{  6, 10 },
+		{  0,  6 },
+		{  0,  0 }
+	}
+};
+
+static const struct scarlett2_device_info clarett_2pre_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_clarett },
+		{ }
+	},
+	.level_input_count = 2,
+	.air_input_count = 2,
+
+	.line_out_descrs = {
+		"Monitor L",
+		"Monitor R",
+		"Headphones L",
+		"Headphones R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  2,  4 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  0 },
+		[SCARLETT2_PORT_TYPE_ADAT]     = {  8,  0 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+		[SCARLETT2_PORT_TYPE_PCM]      = {  4, 12 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 12 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  8 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0,  2 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 26 },
+		{ 0,                            0,  0 },
+	} },
+
+	.meter_map = {
+		{ 22, 12 },
+		{  0, 22 },
+		{  0,  0 }
+	}
+};
+
+static const u8 scarlett2_spdif_clarett_values[] = { 0, 1, 2, 0xff };
+
+static const char * const scarlett2_spdif_clarett_texts[] = {
+	"None",
+	"Optical",
+	"RCA",
+	NULL
+};
+
+static const struct scarlett2_device_info clarett_4pre_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_clarett },
+		{ }
+	},
+	.level_input_count = 2,
+	.air_input_count = 4,
+
+	.spdif_mode_control_name = "S/PDIF Source Capture Enum",
+	.spdif_mode_values = scarlett2_spdif_clarett_values,
+	.spdif_mode_texts = scarlett2_spdif_clarett_texts,
+
+	.line_out_descrs = {
+		"Monitor L",
+		"Monitor R",
+		"Headphones 1 L",
+		"Headphones 1 R",
+		"Headphones 2 L",
+		"Headphones 2 R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  8,  6 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+		[SCARLETT2_PORT_TYPE_ADAT]     = {  8,  0 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+		[SCARLETT2_PORT_TYPE_PCM]      = {  8, 18 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 14 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 12 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 24 },
+		{ 0,                            0,  0 },
+	} },
+
+	.meter_map = {
+		{ 26, 18 },
+		{  0, 26 },
+		{  0,  0 }
+	}
+};
+
+static const struct scarlett2_device_info clarett_8pre_info = {
+	.config_sets = (const struct scarlett2_config_set_entry[]) {
+		{ 0, &scarlett2_config_set_clarett },
+		{ }
+	},
+	.level_input_count = 2,
+	.air_input_count = 8,
+
+	.spdif_mode_control_name = "S/PDIF Source Capture Enum",
+	.spdif_mode_values = scarlett2_spdif_clarett_values,
+	.spdif_mode_texts = scarlett2_spdif_clarett_texts,
+
+	.line_out_descrs = {
+		"Monitor L",
+		"Monitor R",
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		"Headphones 1 L",
+		"Headphones 1 R",
+		"Headphones 2 L",
+		"Headphones 2 R",
+	},
+
+	.port_count = {
+		[SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+		[SCARLETT2_PORT_TYPE_ANALOGUE] = {  8, 10 },
+		[SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+		[SCARLETT2_PORT_TYPE_ADAT]     = {  8,  8 },
+		[SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+		[SCARLETT2_PORT_TYPE_PCM]      = { 20, 18 },
+	},
+
+	.mux_assignment = { {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_ADAT,     0,  8 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 14 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_ADAT,     0,  4 },
+		{ SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+		{ 0,                            0,  0 },
+	}, {
+		{ SCARLETT2_PORT_TYPE_PCM,      0, 12 },
+		{ SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+		{ SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+		{ SCARLETT2_PORT_TYPE_NONE,     0, 22 },
+		{ 0,                            0,  0 },
+	} },
+
+	.meter_map = {
+		{ 38, 18 },
+		{  0, 38 },
+		{  0,  0 }
+	}
+};
+
+struct scarlett2_device_entry {
+	const u32 usb_id; /* USB device identifier */
+	const struct scarlett2_device_info *info;
+	const char *series_name;
+};
+
+static const struct scarlett2_device_entry scarlett2_devices[] = {
+	/* Supported Gen 2 devices */
+	{ USB_ID(0x1235, 0x8203), &s6i6_gen2_info, "Scarlett Gen 2" },
+	{ USB_ID(0x1235, 0x8204), &s18i8_gen2_info, "Scarlett Gen 2" },
+	{ USB_ID(0x1235, 0x8201), &s18i20_gen2_info, "Scarlett Gen 2" },
+
+	/* Supported Gen 3 devices */
+	{ USB_ID(0x1235, 0x8211), &solo_gen3_info, "Scarlett Gen 3" },
+	{ USB_ID(0x1235, 0x8210), &s2i2_gen3_info, "Scarlett Gen 3" },
+	{ USB_ID(0x1235, 0x8212), &s4i4_gen3_info, "Scarlett Gen 3" },
+	{ USB_ID(0x1235, 0x8213), &s8i6_gen3_info, "Scarlett Gen 3" },
+	{ USB_ID(0x1235, 0x8214), &s18i8_gen3_info, "Scarlett Gen 3" },
+	{ USB_ID(0x1235, 0x8215), &s18i20_gen3_info, "Scarlett Gen 3" },
+
+	/* Supported Vocaster devices */
+	{ USB_ID(0x1235, 0x8216), &vocaster_one_info, "Vocaster" },
+	{ USB_ID(0x1235, 0x8217), &vocaster_two_info, "Vocaster" },
+
+	/* Supported Gen 4 devices */
+	{ USB_ID(0x1235, 0x8218), &solo_gen4_info, "Scarlett Gen 4" },
+	{ USB_ID(0x1235, 0x8219), &s2i2_gen4_info, "Scarlett Gen 4" },
+	{ USB_ID(0x1235, 0x821a), &s4i4_gen4_info, "Scarlett Gen 4" },
+
+	/* Supported Clarett USB/Clarett+ devices */
+	{ USB_ID(0x1235, 0x8206), &clarett_2pre_info, "Clarett USB" },
+	{ USB_ID(0x1235, 0x8207), &clarett_4pre_info, "Clarett USB" },
+	{ USB_ID(0x1235, 0x8208), &clarett_8pre_info, "Clarett USB" },
+	{ USB_ID(0x1235, 0x820a), &clarett_2pre_info, "Clarett+" },
+	{ USB_ID(0x1235, 0x820b), &clarett_4pre_info, "Clarett+" },
+	{ USB_ID(0x1235, 0x820c), &clarett_8pre_info, "Clarett+" },
+
+	/* End of list */
+	{ 0, NULL, NULL },
+};
+
+/* get the starting port index number for a given port type/direction */
+static int scarlett2_get_port_start_num(
+	const int port_count[][SCARLETT2_PORT_DIRNS],
+	int direction, int port_type)
+{
+	int i, num = 0;
+
+	for (i = 0; i < port_type; i++)
+		num += port_count[i][direction];
+
+	return num;
+}
+
+/*** USB Interactions ***/
+
+/* Commands for sending/receiving requests/responses */
+#define SCARLETT2_USB_CMD_INIT 0
+#define SCARLETT2_USB_CMD_REQ  2
+#define SCARLETT2_USB_CMD_RESP 3
+
+#define SCARLETT2_USB_INIT_1        0x00000000
+#define SCARLETT2_USB_INIT_2        0x00000002
+#define SCARLETT2_USB_REBOOT        0x00000003
+#define SCARLETT2_USB_GET_METER     0x00001001
+#define SCARLETT2_USB_GET_MIX       0x00002001
+#define SCARLETT2_USB_SET_MIX       0x00002002
+#define SCARLETT2_USB_GET_MUX       0x00003001
+#define SCARLETT2_USB_SET_MUX       0x00003002
+#define SCARLETT2_USB_INFO_FLASH    0x00004000
+#define SCARLETT2_USB_INFO_SEGMENT  0x00004001
+#define SCARLETT2_USB_ERASE_SEGMENT 0x00004002
+#define SCARLETT2_USB_GET_ERASE     0x00004003
+#define SCARLETT2_USB_WRITE_SEGMENT 0x00004004
+#define SCARLETT2_USB_READ_SEGMENT  0x00004005
+#define SCARLETT2_USB_GET_SYNC      0x00006004
+#define SCARLETT2_USB_GET_DATA      0x00800000
+#define SCARLETT2_USB_SET_DATA      0x00800001
+#define SCARLETT2_USB_DATA_CMD      0x00800002
+#define SCARLETT2_USB_INFO_DEVMAP   0x0080000c
+#define SCARLETT2_USB_GET_DEVMAP    0x0080000d
+
+#define SCARLETT2_USB_CONFIG_SAVE 6
+
+#define SCARLETT2_USB_METER_LEVELS_GET_MAGIC 1
+
+#define SCARLETT2_FLASH_BLOCK_SIZE 4096
+#define SCARLETT2_FLASH_RW_MAX 1024
+#define SCARLETT2_SEGMENT_NUM_MIN 1
+#define SCARLETT2_SEGMENT_NUM_MAX 4
+
+#define SCARLETT2_SEGMENT_SETTINGS_NAME "App_Settings"
+#define SCARLETT2_SEGMENT_FIRMWARE_NAME "App_Upgrade"
+
+/* Gen 4 device firmware provides access to a base64-encoded
+ * zlib-compressed JSON description of the device's capabilities and
+ * configuration. This device map is made available in
+ * /proc/asound/cardX/device-map.json.zz.b64
+ */
+#define SCARLETT2_DEVMAP_BLOCK_SIZE 1024
+#define SCARLETT2_DEVMAP_FILENAME "device-map.json.zz.b64"
+
+/* proprietary request/response format */
+struct scarlett2_usb_packet {
+	__le32 cmd;
+	__le16 size;
+	__le16 seq;
+	__le32 error;
+	__le32 pad;
+	u8 data[];
+};
+
+static void scarlett2_fill_request_header(struct scarlett2_data *private,
+					  struct scarlett2_usb_packet *req,
+					  u32 cmd, u16 req_size)
+{
+	/* sequence must go up by 1 for each request */
+	u16 seq = private->scarlett2_seq++;
+
+	req->cmd = cpu_to_le32(cmd);
+	req->size = cpu_to_le16(req_size);
+	req->seq = cpu_to_le16(seq);
+	req->error = 0;
+	req->pad = 0;
+}
+
+static int scarlett2_usb_tx(struct usb_device *dev, int interface,
+			    void *buf, u16 size)
+{
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			SCARLETT2_USB_CMD_REQ,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			0, interface, buf, size);
+}
+
+static int scarlett2_usb_rx(struct usb_device *dev, int interface,
+			    u32 usb_req, void *buf, u16 size)
+{
+	return snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			usb_req,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			0, interface, buf, size);
+}
+
+/* Send a proprietary format request to the Scarlett interface */
+static int scarlett2_usb_nopm(struct usb_mixer_interface *mixer, u32 cmd,
+			      void *req_data, u16 req_size,
+			      void *resp_data, u16 resp_size)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	struct usb_device *dev = mixer->chip->dev;
+	int retries = 0;
+	const int max_retries = 5;
+	int err;
+
+	struct scarlett2_usb_packet *req __free(kfree) = NULL;
+	size_t req_buf_size = struct_size(req, data, req_size);
+	req = kmalloc_flex(*req, data, req_size);
+	if (!req)
+		return -ENOMEM;
+
+	struct scarlett2_usb_packet *resp __free(kfree) = NULL;
+	size_t resp_buf_size = struct_size(resp, data, resp_size);
+	resp = kmalloc_flex(*resp, data, resp_size);
+	if (!resp)
+		return -ENOMEM;
+
+	guard(mutex)(&private->usb_mutex);
+
+	/* build request message and send it */
+
+	scarlett2_fill_request_header(private, req, cmd, req_size);
+
+	if (req_size)
+		memcpy(req->data, req_data, req_size);
+
+retry:
+	err = scarlett2_usb_tx(dev, private->bInterfaceNumber,
+			       req, req_buf_size);
+
+	if (err != req_buf_size) {
+		if (err == -EPROTO && ++retries <= max_retries) {
+			msleep(5 * (1 << (retries - 1)));
+			goto retry;
+		}
+		usb_audio_err(
+			mixer->chip,
+			"%s USB request result cmd %x was %d\n",
+			private->series_name, cmd, err);
+		return -EINVAL;
+	}
+
+	if (!wait_for_completion_timeout(&private->cmd_done,
+					 msecs_to_jiffies(1000))) {
+		usb_audio_err(
+			mixer->chip,
+			"%s USB request timed out, cmd %x\n",
+			private->series_name, cmd);
+
+		return -ETIMEDOUT;
+	}
+
+	/* send a second message to get the response */
+
+	err = scarlett2_usb_rx(dev, private->bInterfaceNumber,
+			       SCARLETT2_USB_CMD_RESP,
+			       resp, resp_buf_size);
+
+	/* validate the response */
+
+	if (err != resp_buf_size) {
+
+		/* ESHUTDOWN and EPROTO are valid responses to a
+		 * reboot request
+		 */
+		if (cmd == SCARLETT2_USB_REBOOT &&
+		    (err == -ESHUTDOWN || err == -EPROTO))
+			return 0;
+
+		usb_audio_err(
+			mixer->chip,
+			"%s USB response result cmd %x was %d expected %zu\n",
+			private->series_name, cmd, err, resp_buf_size);
+		return -EINVAL;
+	}
+
+	/* cmd/seq/size should match except when initialising
+	 * seq sent = 1, response = 0
+	 */
+	if (resp->cmd != req->cmd ||
+	    (resp->seq != req->seq &&
+		(le16_to_cpu(req->seq) != 1 || resp->seq != 0)) ||
+	    resp_size != le16_to_cpu(resp->size) ||
+	    resp->error ||
+	    resp->pad) {
+		usb_audio_err(
+			mixer->chip,
+			"%s USB invalid response; "
+			   "cmd tx/rx %d/%d seq %d/%d size %d/%d "
+			   "error %d pad %d\n",
+			private->series_name,
+			le32_to_cpu(req->cmd), le32_to_cpu(resp->cmd),
+			le16_to_cpu(req->seq), le16_to_cpu(resp->seq),
+			resp_size, le16_to_cpu(resp->size),
+			le32_to_cpu(resp->error),
+			le32_to_cpu(resp->pad));
+		return -EINVAL;
+	}
+
+	if (resp_data && resp_size > 0)
+		memcpy(resp_data, resp->data, resp_size);
+
+	return err;
+}
+
+static int scarlett2_usb(struct usb_mixer_interface *mixer, u32 cmd,
+			 void *req_data, u16 req_size,
+			 void *resp_data, u16 resp_size)
+{
+	CLASS(snd_usb_lock, pm)(mixer->chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	return scarlett2_usb_nopm(mixer, cmd, req_data, req_size,
+				  resp_data, resp_size);
+}
+
+/* Send a USB message to get data; result placed in *buf */
+static int scarlett2_usb_get(
+	struct usb_mixer_interface *mixer,
+	int offset, void *buf, int size)
+{
+	struct {
+		__le32 offset;
+		__le32 size;
+	} __packed req;
+
+	req.offset = cpu_to_le32(offset);
+	req.size = cpu_to_le32(size);
+	return scarlett2_usb(mixer, SCARLETT2_USB_GET_DATA,
+			     &req, sizeof(req), buf, size);
+}
+
+/* Return true if the given configuration item is present in the
+ * configuration set used by this device.
+ */
+static int scarlett2_has_config_item(
+	struct scarlett2_data *private, int config_item_num)
+{
+	return !!private->config_set->items[config_item_num].offset;
+}
+
+/* Send a USB message to get configuration parameters; result placed in *buf */
+static int scarlett2_usb_get_config(
+	struct usb_mixer_interface *mixer,
+	int config_item_num, int count, void *buf)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_config *config_item =
+		&private->config_set->items[config_item_num];
+	int size, err, i;
+	u8 *buf_8;
+	u8 value;
+
+	/* Check that the configuration item is present in the
+	 * configuration set used by this device
+	 */
+	if (!config_item->offset)
+		return -EFAULT;
+
+	/* Writes to the parameter buffer are always 1 byte */
+	size = config_item->size ? config_item->size : 8;
+
+	/* For byte-sized parameters, retrieve directly into buf */
+	if (size >= 8) {
+		size = size / 8 * count;
+		err = scarlett2_usb_get(mixer, config_item->offset, buf, size);
+		if (err < 0)
+			return err;
+		if (config_item->size == 16) {
+			u16 *buf_16 = buf;
+
+			for (i = 0; i < count; i++, buf_16++)
+				*buf_16 = le16_to_cpu(*(__le16 *)buf_16);
+		} else if (config_item->size == 32) {
+			u32 *buf_32 = (u32 *)buf;
+
+			for (i = 0; i < count; i++, buf_32++)
+				*buf_32 = le32_to_cpu(*(__le32 *)buf_32);
+		}
+		return 0;
+	}
+
+	/* For bit-sized parameters, retrieve into value */
+	err = scarlett2_usb_get(mixer, config_item->offset, &value, 1);
+	if (err < 0)
+		return err;
+
+	/* then unpack from value into buf[] */
+	buf_8 = buf;
+	for (i = 0; i < 8 && i < count; i++, value >>= 1)
+		*buf_8++ = value & 1;
+
+	return 0;
+}
+
+/* Send a SCARLETT2_USB_SET_DATA command.
+ * offset: location in the device's data space
+ * size: size in bytes of the value (1, 2, 4)
+ */
+static int scarlett2_usb_set_data(
+	struct usb_mixer_interface *mixer,
+	int offset, int size, int value)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	struct {
+		__le32 offset;
+		__le32 size;
+		__le32 value;
+	} __packed req;
+
+	req.offset = cpu_to_le32(offset);
+	req.size = cpu_to_le32(size);
+	req.value = cpu_to_le32(value);
+	return scarlett2_usb(private->mixer, SCARLETT2_USB_SET_DATA,
+			     &req, sizeof(u32) * 2 + size, NULL, 0);
+}
+
+/* Send a SCARLETT2_USB_SET_DATA command with multiple values.
+ * offset: location in the device's data space
+ * size: size in bytes of each value (1, 2, 4)
+ * count: number of values
+ */
+static int scarlett2_usb_set_data_buf(
+	struct usb_mixer_interface *mixer,
+	int offset, int size, int count, void *buf)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int bytes = size * count;
+	struct {
+		__le32 offset;
+		__le32 size;
+		u8 data[];
+	} __packed *req;
+	int err;
+	size_t buf_size = struct_size(req, data, bytes);
+
+	req = kmalloc_flex(*req, data, bytes);
+	if (!req)
+		return -ENOMEM;
+
+	req->offset = cpu_to_le32(offset);
+	req->size = cpu_to_le32(bytes);
+	if (size == 1) {
+		memcpy(req->data, buf, count);
+	} else if (size == 2) {
+		u16 *buf_16 = buf;
+		int i;
+
+		for (i = 0; i < count; i++)
+			((__le16 *)req->data)[i] = cpu_to_le16(buf_16[i]);
+	} else {
+		u32 *buf_32 = buf;
+		int i;
+
+		for (i = 0; i < count; i++)
+			((__le32 *)req->data)[i] = cpu_to_le32(buf_32[i]);
+	}
+
+	err = scarlett2_usb(private->mixer, SCARLETT2_USB_SET_DATA,
+			    req, buf_size, NULL, 0);
+
+	kfree(req);
+	return err;
+}
+
+/* Send a SCARLETT2_USB_DATA_CMD command.
+ * Configuration changes require activation with this after they have
+ * been uploaded by a previous SCARLETT2_USB_SET_DATA.
+ * The value for activate needed is determined by the configuration
+ * item.
+ */
+static int scarlett2_usb_activate_config(
+	struct usb_mixer_interface *mixer, int activate)
+{
+	__le32 req;
+
+	req = cpu_to_le32(activate);
+	return scarlett2_usb(mixer, SCARLETT2_USB_DATA_CMD,
+			     &req, sizeof(req), NULL, 0);
+}
+
+/* Send USB messages to set a SCARLETT2_CONFIG_* parameter */
+static int scarlett2_usb_set_config(
+	struct usb_mixer_interface *mixer,
+	int config_item_num, int index, int value)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_config_set *config_set = private->config_set;
+	const struct scarlett2_config *config_item =
+		&config_set->items[config_item_num];
+	int offset, size;
+	int err;
+
+	/* Check that the configuration item is present in the
+	 * configuration set used by this device
+	 */
+	if (!config_item->offset)
+		return -EFAULT;
+
+	/* Write via the parameter buffer? */
+	if (config_item->pbuf) {
+		if (!config_set->param_buf_addr)
+			return -EFAULT;
+
+		/* Place index in param_buf_addr + 1 */
+		err = scarlett2_usb_set_data(
+			mixer, config_set->param_buf_addr + 1, 1, index);
+		if (err < 0)
+			return err;
+
+		/* Place value in param_buf_addr */
+		err = scarlett2_usb_set_data(
+			mixer, config_set->param_buf_addr, 1, value);
+		if (err < 0)
+			return err;
+
+		/* Activate the write through the parameter buffer */
+		return scarlett2_usb_activate_config(
+			mixer, config_item->activate);
+	}
+
+	/* Direct writes (not via the parameter buffer) need NVRAM
+	 * save and support bit-modification
+	 */
+
+	/* Cancel any pending NVRAM save */
+	cancel_delayed_work_sync(&private->work);
+
+	/* Convert config_item->size in bits to size in bytes and
+	 * calculate offset
+	 */
+	if (config_item->size >= 8) {
+		size = config_item->size / 8;
+		offset = config_item->offset + index * size;
+
+	/* If updating a bit, retrieve the old value, set/clear the
+	 * bit as needed, and update value
+	 */
+	} else {
+		u8 tmp;
+
+		size = 1;
+		offset = config_item->offset;
+
+		err = scarlett2_usb_get(mixer, offset, &tmp, 1);
+		if (err < 0)
+			return err;
+
+		if (value)
+			tmp |= (1 << index);
+		else
+			tmp &= ~(1 << index);
+
+		value = tmp;
+	}
+
+	/* Write the new value */
+	err = scarlett2_usb_set_data(mixer, offset, size, value);
+	if (err < 0)
+		return err;
+
+	/* Activate the change */
+	err = scarlett2_usb_activate_config(mixer, config_item->activate);
+	if (err < 0)
+		return err;
+
+	/* Interfaces with parameter buffer writes don't need a
+	 * separate save step
+	 */
+	if (config_set->param_buf_addr)
+		return 0;
+
+	/* Schedule the change to be written to NVRAM */
+	if (config_item->activate != SCARLETT2_USB_CONFIG_SAVE)
+		schedule_delayed_work(&private->work, msecs_to_jiffies(2000));
+
+	return 0;
+}
+
+/* Send USB messages to set a SCARLETT2_CONFIG_* parameter with
+ * multiple values
+ */
+static int scarlett2_usb_set_config_buf(
+	struct usb_mixer_interface *mixer,
+	int config_item_num, int index, int count, void *buf)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_config_set *config_set = private->config_set;
+	const struct scarlett2_config *config_item =
+		&config_set->items[config_item_num];
+	int offset, size;
+	int err;
+
+	/* Check that the configuration item is present in the
+	 * configuration set used by this device
+	 */
+	if (!config_item->offset)
+		return -EFAULT;
+
+	/* Convert config_item->size in bits to size in bytes and
+	 * calculate offset
+	 */
+	if (config_item->size >= 8) {
+		size = config_item->size / 8;
+		offset = config_item->offset + index * size;
+
+	/* Bit updates not supported */
+	} else {
+		return -EFAULT;
+	}
+
+	/* Write the new values */
+	err = scarlett2_usb_set_data_buf(mixer, offset, size, count, buf);
+	if (err < 0)
+		return err;
+
+	/* Activate the change */
+	return scarlett2_usb_activate_config(mixer, config_item->activate);
+}
+
+/* Send SCARLETT2_USB_DATA_CMD SCARLETT2_USB_CONFIG_SAVE */
+static void scarlett2_config_save(struct usb_mixer_interface *mixer)
+{
+	__le32 req = cpu_to_le32(SCARLETT2_USB_CONFIG_SAVE);
+	int err = scarlett2_usb(mixer, SCARLETT2_USB_DATA_CMD,
+				&req, sizeof(req), NULL, 0);
+
+	if (err < 0)
+		usb_audio_err(mixer->chip, "config save failed: %d\n", err);
+}
+
+/* The USB suspend callback must not acquire another PM reference. */
+static void scarlett2_config_save_nopm(struct usb_mixer_interface *mixer)
+{
+	__le32 req = cpu_to_le32(SCARLETT2_USB_CONFIG_SAVE);
+	int err = scarlett2_usb_nopm(mixer, SCARLETT2_USB_DATA_CMD,
+				     &req, sizeof(req), NULL, 0);
+
+	if (err < 0)
+		usb_audio_err(mixer->chip, "config save failed: %d\n", err);
+}
+
+/* Delayed work to save config */
+static void scarlett2_config_save_work(struct work_struct *work)
+{
+	struct scarlett2_data *private =
+		container_of(work, struct scarlett2_data, work.work);
+
+	scarlett2_config_save(private->mixer);
+}
+
+/* Send a USB message to get sync status; result placed in *sync */
+static int scarlett2_usb_get_sync_status(
+	struct usb_mixer_interface *mixer,
+	u8 *sync)
+{
+	__le32 data;
+	int err;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_GET_SYNC,
+			    NULL, 0, &data, sizeof(data));
+	if (err < 0)
+		return err;
+
+	*sync = !!data;
+	return 0;
+}
+
+/* Return true if the device has a mixer that we can control */
+static int scarlett2_has_mixer(struct scarlett2_data *private)
+{
+	return !!private->info->mux_assignment[0][0].count;
+}
+
+/* Map from mixer value to (db + 80) * 2
+ * (reverse of scarlett2_mixer_values[])
+ */
+static int scarlett2_mixer_value_to_db(int value)
+{
+	int i;
+
+	for (i = 0; i < SCARLETT2_MIXER_VALUE_COUNT; i++)
+		if (scarlett2_mixer_values[i] >= value)
+			return i;
+	return SCARLETT2_MIXER_MAX_VALUE;
+}
+
+/* Send a USB message to get the volumes for all inputs of one mix
+ * and put the values into private->mix[]
+ */
+static int scarlett2_usb_get_mix(struct usb_mixer_interface *mixer,
+				 int mix_num)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	int num_mixer_in = private->num_mix_in;
+	int err, i, j;
+
+	struct {
+		__le16 mix_num;
+		__le16 count;
+	} __packed req;
+
+	__le16 data[SCARLETT2_INPUT_MIX_MAX];
+
+	req.mix_num = cpu_to_le16(mix_num);
+	req.count = cpu_to_le16(num_mixer_in);
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_GET_MIX,
+			    &req, sizeof(req),
+			    data, num_mixer_in * sizeof(u16));
+	if (err < 0)
+		return err;
+
+	for (i = 0, j = mix_num * num_mixer_in; i < num_mixer_in; i++, j++)
+		private->mix[j] = scarlett2_mixer_value_to_db(
+			le16_to_cpu(data[i]));
+
+	return 0;
+}
+
+/* Send a USB message to set the volumes for all inputs of one mix
+ * (values obtained from private->mix[])
+ */
+static int scarlett2_usb_set_mix(struct usb_mixer_interface *mixer,
+				 int mix_num)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	struct {
+		__le16 mix_num;
+		__le16 data[SCARLETT2_INPUT_MIX_MAX];
+	} __packed req;
+
+	int i, j;
+	int num_mixer_in = private->num_mix_in;
+
+	req.mix_num = cpu_to_le16(mix_num);
+
+	for (i = 0, j = mix_num * num_mixer_in; i < num_mixer_in; i++, j++)
+		req.data[i] = cpu_to_le16(
+			scarlett2_mixer_values[private->mix[j]]
+		);
+
+	return scarlett2_usb(mixer, SCARLETT2_USB_SET_MIX,
+			     &req, (num_mixer_in + 1) * sizeof(u16),
+			     NULL, 0);
+}
+
+/* Convert a port number index (per info->port_count) to a hardware ID */
+static u32 scarlett2_mux_src_num_to_id(
+	const int port_count[][SCARLETT2_PORT_DIRNS], int num)
+{
+	int port_type;
+
+	for (port_type = 0;
+	     port_type < SCARLETT2_PORT_TYPE_COUNT;
+	     port_type++) {
+		if (num < port_count[port_type][SCARLETT2_PORT_IN])
+			return scarlett2_ports[port_type].id | num;
+		num -= port_count[port_type][SCARLETT2_PORT_IN];
+	}
+
+	/* Oops */
+	return 0;
+}
+
+/* Convert a hardware ID to a port number index */
+static u32 scarlett2_mux_id_to_num(
+	const int port_count[][SCARLETT2_PORT_DIRNS], int direction, u32 id)
+{
+	int port_type;
+	int port_num = 0;
+
+	for (port_type = 0;
+	     port_type < SCARLETT2_PORT_TYPE_COUNT;
+	     port_type++) {
+		int base = scarlett2_ports[port_type].id;
+		int count = port_count[port_type][direction];
+
+		if (id >= base && id < base + count)
+			return port_num + id - base;
+		port_num += count;
+	}
+
+	/* Oops */
+	return -1;
+}
+
+/* Convert one mux entry from the interface and load into private->mux[] */
+static void scarlett2_usb_populate_mux(struct scarlett2_data *private,
+				       u32 mux_entry)
+{
+	const struct scarlett2_device_info *info = private->info;
+	const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
+
+	int dst_idx, src_idx;
+
+	dst_idx = scarlett2_mux_id_to_num(port_count, SCARLETT2_PORT_OUT,
+					  mux_entry & 0xFFF);
+	if (dst_idx < 0)
+		return;
+
+	if (dst_idx >= private->num_mux_dsts) {
+		usb_audio_err(private->mixer->chip,
+			"BUG: scarlett2_mux_id_to_num(%06x, OUT): %d >= %d",
+			mux_entry, dst_idx, private->num_mux_dsts);
+		return;
+	}
+
+	src_idx = scarlett2_mux_id_to_num(port_count, SCARLETT2_PORT_IN,
+					  mux_entry >> 12);
+	if (src_idx < 0)
+		return;
+
+	if (src_idx >= private->num_mux_srcs) {
+		usb_audio_err(private->mixer->chip,
+			"BUG: scarlett2_mux_id_to_num(%06x, IN): %d >= %d",
+			mux_entry, src_idx, private->num_mux_srcs);
+		return;
+	}
+
+	private->mux[dst_idx] = src_idx;
+}
+
+/* Update the meter level map
+ *
+ * The meter level data from the interface (SCARLETT2_USB_GET_METER
+ * request) is returned in mux_assignment order, but to avoid exposing
+ * that to userspace, scarlett2_meter_ctl_get() rearranges the data
+ * into scarlett2_ports order using the meter_level_map[] array which
+ * is set up by this function.
+ *
+ * In addition, the meter level data values returned from the
+ * interface are invalid for destinations where:
+ *
+ * - the source is "Off"; therefore we set those values to zero (map
+ *   value of 255)
+ *
+ * - the source is assigned to a previous (with respect to the
+ *   mux_assignment order) destination; therefore we set those values
+ *   to the value previously reported for that source
+ */
+static void scarlett2_update_meter_level_map(struct scarlett2_data *private)
+{
+	const struct scarlett2_device_info *info = private->info;
+	const struct scarlett2_meter_entry *entry;
+
+	/* sources already assigned to a destination
+	 * value is 255 for None, otherwise the value of i
+	 * (index into array returned by
+	 * scarlett2_usb_get_meter_levels())
+	 */
+	u8 seen_src[SCARLETT2_MAX_SRCS] = { 1 };
+	u8 seen_src_value[SCARLETT2_MAX_SRCS] = { 255 };
+
+	/* index in meter_map[] order */
+	int i = 0;
+
+	/* go through the meter_map[] entries */
+	for (entry = info->meter_map;
+	     entry->count;
+	     entry++) {
+
+		/* fill in each meter_level_map[] entry */
+		int j, mux_idx;
+
+		for (j = 0, mux_idx = entry->start;
+		     j < entry->count;
+		     i++, j++, mux_idx++) {
+
+			/* convert mux_idx using line_out_unmap[] */
+			int map_mux_idx = (
+			    info->line_out_remap_enable &&
+			    mux_idx < private->num_line_out
+			) ? info->line_out_unmap[mux_idx]
+			  : mux_idx;
+
+			/* check which source is connected, and if
+			 * that source is already connected elsewhere,
+			 * use that existing connection's destination
+			 * for this meter entry instead
+			 */
+			int mux_src = private->mux[mux_idx];
+
+			if (!seen_src[mux_src]) {
+				seen_src[mux_src] = 1;
+				seen_src_value[mux_src] = i;
+			}
+			private->meter_level_map[map_mux_idx] =
+				seen_src_value[mux_src];
+		}
+	}
+}
+
+/* Send USB message to get mux inputs and then populate private->mux[] */
+static int scarlett2_usb_get_mux(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int count = private->num_mux_dsts;
+	int err, i;
+
+	struct {
+		__le16 num;
+		__le16 count;
+	} __packed req;
+
+	__le32 data[SCARLETT2_MUX_MAX];
+
+	private->mux_updated = 0;
+
+	req.num = 0;
+	req.count = cpu_to_le16(count);
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_GET_MUX,
+			    &req, sizeof(req),
+			    data, count * sizeof(u32));
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < count; i++)
+		scarlett2_usb_populate_mux(private, le32_to_cpu(data[i]));
+
+	scarlett2_update_meter_level_map(private);
+
+	return 0;
+}
+
+/* Send USB messages to set mux inputs */
+static int scarlett2_usb_set_mux(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
+	int table;
+
+	struct {
+		__le16 pad;
+		__le16 num;
+		__le32 data[SCARLETT2_MUX_MAX];
+	} __packed req;
+
+	req.pad = 0;
+
+	/* set mux settings for each rate */
+	for (table = 0; table < SCARLETT2_MUX_TABLES; table++) {
+		const struct scarlett2_mux_entry *entry;
+
+		/* i counts over the output array */
+		int i = 0, err;
+
+		req.num = cpu_to_le16(table);
+
+		/* loop through each entry */
+		for (entry = info->mux_assignment[table];
+		     entry->count;
+		     entry++) {
+			int j;
+			int port_type = entry->port_type;
+			int port_idx = entry->start;
+			int mux_idx = scarlett2_get_port_start_num(port_count,
+				SCARLETT2_PORT_OUT, port_type) + port_idx;
+			int dst_id = scarlett2_ports[port_type].id + port_idx;
+
+			/* Empty slots */
+			if (!dst_id) {
+				for (j = 0; j < entry->count; j++)
+					req.data[i++] = 0;
+				continue;
+			}
+
+			/* Non-empty mux slots use the lower 12 bits
+			 * for the destination and next 12 bits for
+			 * the source
+			 */
+			for (j = 0; j < entry->count; j++) {
+				int src_id = scarlett2_mux_src_num_to_id(
+					port_count, private->mux[mux_idx++]);
+				req.data[i++] = cpu_to_le32(dst_id |
+							    src_id << 12);
+				dst_id++;
+			}
+		}
+
+		err = scarlett2_usb(mixer, SCARLETT2_USB_SET_MUX,
+				    &req, (i + 1) * sizeof(u32),
+				    NULL, 0);
+		if (err < 0)
+			return err;
+	}
+
+	scarlett2_update_meter_level_map(private);
+
+	return 0;
+}
+
+/* Send USB message to get meter levels */
+static int scarlett2_usb_get_meter_levels(struct usb_mixer_interface *mixer,
+					  u16 num_meters, u16 *levels)
+{
+	struct {
+		__le16 pad;
+		__le16 num_meters;
+		__le32 magic;
+	} __packed req;
+	__le32 resp[SCARLETT2_MAX_METERS];
+	int i, err;
+
+	req.pad = 0;
+	req.num_meters = cpu_to_le16(num_meters);
+	req.magic = cpu_to_le32(SCARLETT2_USB_METER_LEVELS_GET_MAGIC);
+	err = scarlett2_usb(mixer, SCARLETT2_USB_GET_METER,
+			    &req, sizeof(req), resp, num_meters * sizeof(u32));
+	if (err < 0)
+		return err;
+
+	/* copy, convert to u16 */
+	for (i = 0; i < num_meters; i++)
+		levels[i] = le32_to_cpu(resp[i]);
+
+	return 0;
+}
+
+/* For config items with mute=1, xor bits 0 & 1 together to get the
+ * current/next state. This won't have any effect on values which are
+ * only ever 0/1.
+ */
+static uint8_t scarlett2_decode_muteable(uint8_t v)
+{
+	return (v ^ (v >> 1)) & 1;
+}
+
+/*** Control Functions ***/
+
+/* helper function to create a new control */
+static int scarlett2_add_new_ctl(struct usb_mixer_interface *mixer,
+				 const struct snd_kcontrol_new *ncontrol,
+				 int index, int channels, const char *name,
+				 struct snd_kcontrol **kctl_return)
+{
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *elem;
+	int err;
+
+	elem = kzalloc_obj(*elem);
+	if (!elem)
+		return -ENOMEM;
+
+	/* We set USB_MIXER_BESPOKEN type, so that the core USB mixer code
+	 * ignores them for resume and other operations.
+	 * Also, the head.id field is set to 0, as we don't use this field.
+	 */
+	elem->head.mixer = mixer;
+	elem->control = index;
+	elem->head.id = 0;
+	elem->channels = channels;
+	elem->val_type = USB_MIXER_BESPOKEN;
+
+	kctl = snd_ctl_new1(ncontrol, elem);
+	if (!kctl) {
+		kfree(elem);
+		return -ENOMEM;
+	}
+	kctl->private_free = snd_usb_mixer_elem_free;
+
+	strscpy(kctl->id.name, name, sizeof(kctl->id.name));
+
+	err = snd_usb_mixer_add_control(&elem->head, kctl);
+	if (err < 0)
+		return err;
+
+	if (kctl_return)
+		*kctl_return = kctl;
+
+	return 0;
+}
+
+/*** Firmware Version Control ***/
+
+static int scarlett2_firmware_version_ctl_get(
+	struct snd_kcontrol *kctl,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] = private->firmware_version;
+
+	return 0;
+}
+
+static int scarlett2_firmware_version_ctl_info(
+	struct snd_kcontrol *kctl,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+
+	return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_firmware_version_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.name = "",
+	.info = scarlett2_firmware_version_ctl_info,
+	.get  = scarlett2_firmware_version_ctl_get
+};
+
+static int scarlett2_add_firmware_version_ctl(
+	struct usb_mixer_interface *mixer)
+{
+	return scarlett2_add_new_ctl(mixer, &scarlett2_firmware_version_ctl,
+				     0, 0, "Firmware Version", NULL);
+}
+
+/*** Minimum Firmware Version Control ***/
+
+static int scarlett2_min_firmware_version_ctl_get(
+	struct snd_kcontrol *kctl,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] =
+		private->info->config_sets[0].from_firmware_version;
+
+	return 0;
+}
+
+static int scarlett2_min_firmware_version_ctl_info(
+	struct snd_kcontrol *kctl,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+
+	return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_min_firmware_version_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.name = "",
+	.info = scarlett2_min_firmware_version_ctl_info,
+	.get  = scarlett2_min_firmware_version_ctl_get
+};
+
+static int scarlett2_add_min_firmware_version_ctl(
+	struct usb_mixer_interface *mixer)
+{
+	return scarlett2_add_new_ctl(mixer, &scarlett2_min_firmware_version_ctl,
+				     0, 0, "Minimum Firmware Version", NULL);
+}
+
+/*** Sync Control ***/
+
+/* Update sync control after receiving notification that the status
+ * has changed
+ */
+static int scarlett2_update_sync(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	private->sync_updated = 0;
+	return scarlett2_usb_get_sync_status(mixer, &private->sync);
+}
+
+static int scarlett2_sync_ctl_info(struct snd_kcontrol *kctl,
+				   struct snd_ctl_elem_info *uinfo)
+{
+	static const char *texts[2] = {
+		"Unlocked", "Locked"
+	};
+	return snd_ctl_enum_info(uinfo, 1, 2, texts);
+}
+
+static int scarlett2_sync_ctl_get(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->sync_updated) {
+		err = scarlett2_update_sync(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] = private->sync;
+	return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_sync_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.name = "",
+	.info = scarlett2_sync_ctl_info,
+	.get  = scarlett2_sync_ctl_get
+};
+
+static int scarlett2_add_sync_ctl(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	/* devices without a mixer also don't support reporting sync status */
+	if (!scarlett2_has_mixer(private))
+		return 0;
+
+	return scarlett2_add_new_ctl(mixer, &scarlett2_sync_ctl,
+				     0, 1, "Sync Status", &private->sync_ctl);
+}
+
+/*** Autogain Switch and Status Controls ***/
+
+/* Forward declarations as phantom power and autogain can disable each other */
+static int scarlett2_check_input_phantom_updated(struct usb_mixer_interface *);
+static int scarlett2_phantom_is_switching(struct scarlett2_data *, int);
+
+/* Set the access mode of a control to read-only (val = 0) or
+ * read-write (val = 1).
+ */
+static void scarlett2_set_ctl_access(struct snd_kcontrol *kctl, int val)
+{
+	if (val)
+		kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_WRITE;
+	else
+		kctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_WRITE;
+}
+
+/* Check if autogain is running on any input */
+static int scarlett2_autogain_is_running(struct scarlett2_data *private)
+{
+	int i;
+
+	/* autogain_status[] is 0 if autogain is running */
+	for (i = 0; i < private->info->gain_input_count; i++)
+		if (!private->autogain_status[i])
+			return 1;
+
+	return 0;
+}
+
+static int scarlett2_update_autogain(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int err, i;
+	u8 raw_autogain_status[SCARLETT2_INPUT_GAIN_MAX];
+	s8 ag_target_values[SCARLETT2_AG_TARGET_COUNT];
+
+	private->autogain_updated = 0;
+
+	if (!info->gain_input_count)
+		return 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_AUTOGAIN_SWITCH,
+		info->gain_input_count, private->autogain_switch);
+	if (err < 0)
+		return err;
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_AUTOGAIN_STATUS,
+		info->gain_input_count, raw_autogain_status);
+	if (err < 0)
+		return err;
+
+	/* Translate autogain_switch and raw_autogain_status into
+	 * autogain_status.
+	 *
+	 * When autogain_switch[] is set, the status is the first
+	 * element in scarlett2_autogain_status_texts[] (Running). The
+	 * subsequent elements correspond to the status value from the
+	 * device (raw_autogain_status[]) + 1. The last element is
+	 * "Invalid", in case the device reports a status outside the
+	 * range of scarlett2_autogain_status_texts[].
+	 */
+	for (i = 0; i < info->gain_input_count; i++)
+		if (private->autogain_switch[i])
+			private->autogain_status[i] = 0;
+		else if (raw_autogain_status[i] <
+				private->num_autogain_status_texts - 1)
+			private->autogain_status[i] =
+				raw_autogain_status[i] + 1;
+		else
+			private->autogain_status[i] =
+				private->num_autogain_status_texts - 1;
+
+	for (i = 0; i < SCARLETT2_AG_TARGET_COUNT; i++)
+		if (scarlett2_has_config_item(private,
+					      scarlett2_ag_target_configs[i])) {
+			err = scarlett2_usb_get_config(
+				mixer, scarlett2_ag_target_configs[i],
+				1, &ag_target_values[i]);
+			if (err < 0)
+				return err;
+		}
+
+	/* convert from negative dBFS as used by the device */
+	for (i = 0; i < SCARLETT2_AG_TARGET_COUNT; i++)
+		private->ag_targets[i] = -ag_target_values[i];
+
+	return 0;
+}
+
+/* Update access mode for controls affected by autogain */
+static void scarlett2_autogain_update_access(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int val = !scarlett2_autogain_is_running(private);
+	int i;
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_INPUT_SELECT_SWITCH))
+		scarlett2_set_ctl_access(private->input_select_ctl, val);
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_INPUT_LINK_SWITCH))
+		for (i = 0; i < info->gain_input_count; i++)
+			scarlett2_set_ctl_access(private->input_link_ctls[i],
+						 val);
+	for (i = 0; i < info->gain_input_count; i++)
+		scarlett2_set_ctl_access(private->input_gain_ctls[i], val);
+	for (i = 0; i < info->safe_input_count; i++)
+		scarlett2_set_ctl_access(private->safe_ctls[i], val);
+	for (i = 0; i < info->level_input_count; i++)
+		scarlett2_set_ctl_access(private->level_ctls[i], val);
+	for (i = 0; i < info->air_input_count; i++)
+		scarlett2_set_ctl_access(private->air_ctls[i], val);
+	for (i = 0; i < info->mute_input_count; i++)
+		scarlett2_set_ctl_access(private->input_mute_ctls[i], val);
+	for (i = 0; i < info->phantom_count; i++)
+		scarlett2_set_ctl_access(private->phantom_ctls[i], val);
+	for (i = 0; i < info->dsp_input_count; i++)
+		scarlett2_set_ctl_access(private->dsp_ctls[i], val);
+
+	for (i = 0; i < SCARLETT2_AG_TARGET_COUNT; i++)
+		if (scarlett2_has_config_item(private,
+					      scarlett2_ag_target_configs[i]))
+			scarlett2_set_ctl_access(
+				private->ag_target_ctls[i], val);
+}
+
+/* Notify of access mode change for all controls read-only while
+ * autogain runs.
+ */
+static void scarlett2_autogain_notify_access(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_INPUT_SELECT_SWITCH))
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->input_select_ctl->id);
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_INPUT_LINK_SWITCH))
+		for (i = 0; i < info->gain_input_count; i++)
+			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+				       &private->input_link_ctls[i]->id);
+	for (i = 0; i < info->gain_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->input_gain_ctls[i]->id);
+	for (i = 0; i < info->safe_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->safe_ctls[i]->id);
+	for (i = 0; i < info->level_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->level_ctls[i]->id);
+	for (i = 0; i < info->air_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->air_ctls[i]->id);
+	for (i = 0; i < info->dsp_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->dsp_ctls[i]->id);
+	for (i = 0; i < info->mute_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->input_mute_ctls[i]->id);
+	for (i = 0; i < info->phantom_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->phantom_ctls[i]->id);
+
+	for (i = 0; i < SCARLETT2_AG_TARGET_COUNT; i++)
+		if (scarlett2_has_config_item(private,
+					      scarlett2_ag_target_configs[i]))
+			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+				       &private->ag_target_ctls[i]->id);
+}
+
+/* Call scarlett2_update_autogain() and
+ * scarlett2_autogain_update_access() if autogain_updated is set.
+ */
+static int scarlett2_check_autogain_updated(
+	struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	if (!private->autogain_updated)
+		return 0;
+
+	err = scarlett2_update_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	scarlett2_autogain_update_access(mixer);
+
+	return 0;
+}
+
+/* If autogain_updated is set when a *_ctl_put() function for a
+ * control that is meant to be read-only while autogain is running,
+ * update the autogain status and access mode of affected controls.
+ * Return -EPERM if autogain is running.
+ */
+static int scarlett2_check_put_during_autogain(
+	struct usb_mixer_interface *mixer)
+{
+	int err = scarlett2_check_autogain_updated(mixer);
+
+	if (err < 0)
+		return err;
+
+	if (scarlett2_autogain_is_running(mixer->private_data))
+		return -EPERM;
+
+	return 0;
+}
+
+static int scarlett2_autogain_switch_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	err = scarlett2_check_input_phantom_updated(mixer);
+	if (err < 0)
+		return err;
+
+	return snd_ctl_boolean_mono_info(kctl, uinfo);
+}
+
+static int scarlett2_autogain_switch_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_autogain_updated(mixer);
+	if (err < 0)
+		return err;
+
+	ucontrol->value.enumerated.item[0] =
+		private->autogain_switch[elem->control];
+	return 0;
+}
+
+static int scarlett2_autogain_status_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_autogain_updated(mixer);
+	if (err < 0)
+		return err;
+
+	ucontrol->value.enumerated.item[0] =
+		private->autogain_status[elem->control];
+	return 0;
+}
+
+static int scarlett2_autogain_switch_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_input_phantom_updated(mixer);
+	if (err < 0)
+		return err;
+
+	if (scarlett2_phantom_is_switching(private, index))
+		return -EPERM;
+
+	oval = private->autogain_switch[index];
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->autogain_switch[index] = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_AUTOGAIN_SWITCH, index, val);
+
+	scarlett2_autogain_update_access(mixer);
+	scarlett2_autogain_notify_access(mixer);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_autogain_status_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	return snd_ctl_enum_info(
+		uinfo, 1,
+		private->num_autogain_status_texts,
+		private->config_set->autogain_status_texts);
+}
+
+static const struct snd_kcontrol_new scarlett2_autogain_switch_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_autogain_switch_ctl_info,
+	.get  = scarlett2_autogain_switch_ctl_get,
+	.put  = scarlett2_autogain_switch_ctl_put
+};
+
+static const struct snd_kcontrol_new scarlett2_autogain_status_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.name = "",
+	.info = scarlett2_autogain_status_ctl_info,
+	.get  = scarlett2_autogain_status_ctl_get,
+};
+
+/*** Autogain Target Controls ***/
+
+static int scarlett2_ag_target_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_autogain_updated(mixer);
+	if (err < 0)
+		return err;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = SCARLETT2_AG_TARGET_MIN;
+	uinfo->value.integer.max = 0;
+	uinfo->value.integer.step = 1;
+
+	return 0;
+}
+
+static int scarlett2_ag_target_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->autogain_updated) {
+		err = scarlett2_update_autogain(mixer);
+		if (err < 0)
+			return err;
+	}
+
+	ucontrol->value.integer.value[0] = private->ag_targets[elem->control];
+	return 0;
+}
+
+static int scarlett2_ag_target_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->ag_targets[index];
+	val = clamp(ucontrol->value.integer.value[0],
+		    (long)SCARLETT2_AG_TARGET_MIN, 0L);
+
+	if (oval == val)
+		return 0;
+
+	private->ag_targets[index] = val;
+
+	/* Send new value to the device */
+	err = scarlett2_usb_set_config(
+		mixer, scarlett2_ag_target_configs[index], 1, -val);
+
+	return err < 0 ? err : 1;
+}
+
+static const DECLARE_TLV_DB_MINMAX(
+	db_scale_ag_target, SCARLETT2_AG_TARGET_MIN * 100, 0
+);
+
+static const struct snd_kcontrol_new scarlett2_ag_target_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett2_ag_target_ctl_info,
+	.get  = scarlett2_ag_target_ctl_get,
+	.put  = scarlett2_ag_target_ctl_put,
+	.tlv = { .p = db_scale_ag_target }
+};
+
+/*** Input Select Control ***/
+
+static int scarlett2_update_input_select(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int link_count = info->gain_input_count;
+	int err;
+
+	private->input_select_updated = 0;
+
+	if (!scarlett2_has_config_item(private,
+				       SCARLETT2_CONFIG_INPUT_SELECT_SWITCH) ||
+	    !link_count)
+		return 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_INPUT_SELECT_SWITCH,
+		1, &private->input_select_switch);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_INPUT_LINK_SWITCH,
+		link_count, private->input_link_switch);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static int scarlett2_input_select_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_select_updated) {
+		err = scarlett2_update_input_select(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] = private->input_select_switch;
+	return 0;
+}
+
+static int scarlett2_input_select_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->input_select_switch;
+	val = ucontrol->value.integer.value[0];
+
+	if (val < 0)
+		val = 0;
+	else if (val >= info->gain_input_count)
+		val = info->gain_input_count - 1;
+
+	if (oval == val)
+		return 0;
+
+	private->input_select_switch = val;
+
+	/* Send new value to the device */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_INPUT_SELECT_SWITCH,
+		0, val);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_input_select_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int inputs = private->info->gain_input_count;
+	int i, err;
+	char **values __free(kfree) =
+		kcalloc(inputs, sizeof(char *), GFP_KERNEL);
+
+	if (!values)
+		return -ENOMEM;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_autogain_updated(mixer);
+	if (err < 0)
+		return err;
+
+	/* Loop through each input */
+	for (i = 0; i < inputs; i++) {
+		values[i] = kasprintf(GFP_KERNEL, "Input %d", i + 1);
+		if (!values[i]) {
+			err = -ENOMEM;
+			goto clear;
+		}
+	}
+
+	err = snd_ctl_enum_info(uinfo, 1, i,
+				(const char * const *)values);
+
+clear:
+	for (i = 0; i < inputs; i++)
+		kfree(values[i]);
+
+	return err;
+}
+
+static const struct snd_kcontrol_new scarlett2_input_select_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_input_select_ctl_info,
+	.get  = scarlett2_input_select_ctl_get,
+	.put  = scarlett2_input_select_ctl_put,
+};
+
+/*** Input Link Switch Controls ***/
+
+/* snd_ctl_boolean_mono_info() with autogain-updated check
+ * (for controls that are read-only while autogain is running)
+ */
+static int scarlett2_autogain_disables_ctl_info(struct snd_kcontrol *kctl,
+						struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_autogain_updated(mixer);
+	if (err < 0)
+		return err;
+
+	return snd_ctl_boolean_mono_info(kctl, uinfo);
+}
+
+static int scarlett2_input_link_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_select_updated) {
+		err = scarlett2_update_input_select(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] =
+		private->input_link_switch[elem->control];
+	return 0;
+}
+
+static int scarlett2_input_link_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->input_link_switch[index];
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->input_link_switch[index] = val;
+
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_INPUT_LINK_SWITCH, index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_input_link_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_autogain_disables_ctl_info,
+	.get  = scarlett2_input_link_ctl_get,
+	.put  = scarlett2_input_link_ctl_put
+};
+
+/*** Input Gain Controls ***/
+
+static int scarlett2_update_input_gain(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	private->input_gain_updated = 0;
+
+	if (!info->gain_input_count)
+		return 0;
+
+	return scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_INPUT_GAIN,
+		info->gain_input_count, private->gain);
+}
+
+static int scarlett2_input_gain_ctl_info(struct snd_kcontrol *kctl,
+					 struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_autogain_updated(mixer);
+	if (err < 0)
+		return err;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = SCARLETT2_MAX_GAIN_VALUE;
+	uinfo->value.integer.step = 1;
+
+	return 0;
+}
+
+static int scarlett2_input_gain_ctl_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_gain_updated) {
+		err = scarlett2_update_input_gain(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] =
+		private->gain[elem->control];
+	return 0;
+}
+
+static int scarlett2_input_gain_ctl_put(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->gain[index];
+	val = ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->gain[index] = val;
+
+	/* Send gain change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_INPUT_GAIN,
+				       index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_input_gain_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett2_input_gain_ctl_info,
+	.get  = scarlett2_input_gain_ctl_get,
+	.put  = scarlett2_input_gain_ctl_put,
+	.private_value = 0, /* max value */
+};
+
+/*** Safe Controls ***/
+
+static int scarlett2_update_input_safe(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	private->input_safe_updated = 0;
+
+	if (!info->safe_input_count)
+		return 0;
+
+	return scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_SAFE_SWITCH,
+		info->safe_input_count, private->safe_switch);
+}
+
+static int scarlett2_safe_ctl_get(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_safe_updated) {
+		err = scarlett2_update_input_safe(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] =
+		private->safe_switch[elem->control];
+	return 0;
+}
+
+static int scarlett2_safe_ctl_put(struct snd_kcontrol *kctl,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->safe_switch[index];
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->safe_switch[index] = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_SAFE_SWITCH,
+				       index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_safe_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_autogain_disables_ctl_info,
+	.get  = scarlett2_safe_ctl_get,
+	.put  = scarlett2_safe_ctl_put,
+};
+
+/*** PCM Input Control ***/
+
+static int scarlett2_update_pcm_input_switch(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	private->pcm_input_switch_updated = 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_PCM_INPUT_SWITCH,
+		1, &private->pcm_input_switch);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static int scarlett2_pcm_input_switch_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->pcm_input_switch_updated) {
+		err = scarlett2_update_pcm_input_switch(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] = private->pcm_input_switch;
+	return 0;
+}
+
+static int scarlett2_pcm_input_switch_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->pcm_input_switch;
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->pcm_input_switch = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_PCM_INPUT_SWITCH,
+		0, val);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_pcm_input_switch_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const values[2] = {
+		"Direct", "Mixer"
+	};
+
+	return snd_ctl_enum_info(
+		uinfo, 1, 2, values);
+}
+
+static const struct snd_kcontrol_new scarlett2_pcm_input_switch_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_pcm_input_switch_ctl_info,
+	.get  = scarlett2_pcm_input_switch_ctl_get,
+	.put  = scarlett2_pcm_input_switch_ctl_put
+};
+
+/*** Analogue Line Out Volume Controls ***/
+
+/* Update hardware volume controls after receiving notification that
+ * they have changed
+ */
+static int scarlett2_update_volumes(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	s16 vol;
+	int err, i;
+
+	private->vol_updated = 0;
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_MASTER_VOLUME)) {
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_MASTER_VOLUME,
+			1, &vol);
+		if (err < 0)
+			return err;
+
+		private->master_vol = clamp(vol + SCARLETT2_VOLUME_BIAS,
+					    0, SCARLETT2_VOLUME_BIAS);
+
+		if (scarlett2_has_config_item(private,
+					      SCARLETT2_CONFIG_SW_HW_SWITCH))
+			for (i = 0; i < private->num_line_out; i++)
+				if (private->vol_sw_hw_switch[i])
+					private->vol[i] = private->master_vol;
+	}
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_HEADPHONE_VOLUME)) {
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_HEADPHONE_VOLUME,
+			1, &vol);
+		if (err < 0)
+			return err;
+
+		private->headphone_vol = clamp(vol + SCARLETT2_VOLUME_BIAS,
+					       0, SCARLETT2_VOLUME_BIAS);
+	}
+
+	return 0;
+}
+
+static int scarlett2_volume_ctl_info(struct snd_kcontrol *kctl,
+				     struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = SCARLETT2_VOLUME_BIAS;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static int scarlett2_master_volume_ctl_get(struct snd_kcontrol *kctl,
+					   struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->vol_updated) {
+		err = scarlett2_update_volumes(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->master_vol;
+	return 0;
+}
+
+static int scarlett2_headphone_volume_ctl_get(
+	struct snd_kcontrol *kctl,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->vol_updated) {
+		err = scarlett2_update_volumes(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->headphone_vol;
+	return 0;
+}
+
+static int line_out_remap(struct scarlett2_data *private, int index)
+{
+	const struct scarlett2_device_info *info = private->info;
+
+	if (!info->line_out_remap_enable)
+		return index;
+
+	if (index >= private->num_line_out)
+		return index;
+
+	return info->line_out_remap[index];
+}
+
+static int scarlett2_volume_ctl_get(struct snd_kcontrol *kctl,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = line_out_remap(private, elem->control);
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->vol_updated) {
+		err = scarlett2_update_volumes(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->vol[index];
+	return 0;
+}
+
+static int scarlett2_volume_ctl_put(struct snd_kcontrol *kctl,
+				    struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = line_out_remap(private, elem->control);
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->vol[index];
+	val = ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->vol[index] = val;
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_LINE_OUT_VOLUME,
+				       index, val - SCARLETT2_VOLUME_BIAS);
+
+	return err < 0 ? err : 1;
+}
+
+static const DECLARE_TLV_DB_MINMAX(
+	db_scale_scarlett2_volume, -SCARLETT2_VOLUME_BIAS * 100, 0
+);
+
+static const struct snd_kcontrol_new scarlett2_master_volume_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett2_volume_ctl_info,
+	.get  = scarlett2_master_volume_ctl_get,
+	.private_value = 0, /* max value */
+	.tlv = { .p = db_scale_scarlett2_volume }
+};
+
+static const struct snd_kcontrol_new scarlett2_headphone_volume_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett2_volume_ctl_info,
+	.get  = scarlett2_headphone_volume_ctl_get,
+	.private_value = 0, /* max value */
+	.tlv = { .p = db_scale_scarlett2_volume }
+};
+
+static const struct snd_kcontrol_new scarlett2_line_out_volume_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett2_volume_ctl_info,
+	.get  = scarlett2_volume_ctl_get,
+	.put  = scarlett2_volume_ctl_put,
+	.private_value = 0, /* max value */
+	.tlv = { .p = db_scale_scarlett2_volume }
+};
+
+/*** Mute Switch Controls ***/
+
+static int scarlett2_update_dim_mute(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err, i;
+	u8 mute;
+
+	private->dim_mute_updated = 0;
+
+	if (!scarlett2_has_config_item(private, SCARLETT2_CONFIG_SW_HW_SWITCH))
+		return 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_DIM_MUTE,
+		SCARLETT2_DIM_MUTE_COUNT, private->dim_mute);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
+		private->dim_mute[i] = !!private->dim_mute[i];
+
+	mute = private->dim_mute[SCARLETT2_BUTTON_MUTE];
+
+	for (i = 0; i < private->num_line_out; i++)
+		if (private->vol_sw_hw_switch[i])
+			private->mute_switch[i] = mute;
+
+	return 0;
+}
+
+static int scarlett2_mute_ctl_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = line_out_remap(private, elem->control);
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->dim_mute_updated) {
+		err = scarlett2_update_dim_mute(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->mute_switch[index];
+	return 0;
+}
+
+static int scarlett2_mute_ctl_put(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = line_out_remap(private, elem->control);
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->mute_switch[index];
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->mute_switch[index] = val;
+
+	/* Send mute change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_MUTE_SWITCH,
+				       index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_mute_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_mute_ctl_get,
+	.put  = scarlett2_mute_ctl_put,
+};
+
+/*** HW/SW Volume Switch Controls ***/
+
+static void scarlett2_sw_hw_ctl_ro(struct scarlett2_data *private, int index)
+{
+	private->sw_hw_ctls[index]->vd[0].access &=
+		~SNDRV_CTL_ELEM_ACCESS_WRITE;
+}
+
+static void scarlett2_sw_hw_ctl_rw(struct scarlett2_data *private, int index)
+{
+	private->sw_hw_ctls[index]->vd[0].access |=
+		SNDRV_CTL_ELEM_ACCESS_WRITE;
+}
+
+static int scarlett2_sw_hw_enum_ctl_info(struct snd_kcontrol *kctl,
+					 struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const values[2] = {
+		"SW", "HW"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, 2, values);
+}
+
+static int scarlett2_sw_hw_enum_ctl_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+	int index = line_out_remap(private, elem->control);
+
+	ucontrol->value.enumerated.item[0] = private->vol_sw_hw_switch[index];
+	return 0;
+}
+
+static void scarlett2_vol_ctl_set_writable(struct usb_mixer_interface *mixer,
+					   int index, int value)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	struct snd_card *card = mixer->chip->card;
+
+	/* Set/Clear write bits */
+	if (value) {
+		private->vol_ctls[index]->vd[0].access |=
+			SNDRV_CTL_ELEM_ACCESS_WRITE;
+		private->mute_ctls[index]->vd[0].access |=
+			SNDRV_CTL_ELEM_ACCESS_WRITE;
+	} else {
+		private->vol_ctls[index]->vd[0].access &=
+			~SNDRV_CTL_ELEM_ACCESS_WRITE;
+		private->mute_ctls[index]->vd[0].access &=
+			~SNDRV_CTL_ELEM_ACCESS_WRITE;
+	}
+
+	/* Notify of write bit and possible value change */
+	snd_ctl_notify(card,
+		       SNDRV_CTL_EVENT_MASK_VALUE | SNDRV_CTL_EVENT_MASK_INFO,
+		       &private->vol_ctls[index]->id);
+	snd_ctl_notify(card,
+		       SNDRV_CTL_EVENT_MASK_VALUE | SNDRV_CTL_EVENT_MASK_INFO,
+		       &private->mute_ctls[index]->id);
+}
+
+static int scarlett2_sw_hw_change(struct usb_mixer_interface *mixer,
+				  int ctl_index, int val)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int index = line_out_remap(private, ctl_index);
+	int err;
+
+	private->vol_sw_hw_switch[index] = val;
+
+	/* Change access mode to RO (hardware controlled volume)
+	 * or RW (software controlled volume)
+	 */
+	scarlett2_vol_ctl_set_writable(mixer, ctl_index, !val);
+
+	/* Reset volume/mute to master volume/mute */
+	private->vol[index] = private->master_vol;
+	private->mute_switch[index] = private->dim_mute[SCARLETT2_BUTTON_MUTE];
+
+	/* Set SW volume to current HW volume */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_LINE_OUT_VOLUME,
+		index, private->master_vol - SCARLETT2_VOLUME_BIAS);
+	if (err < 0)
+		return err;
+
+	/* Set SW mute to current HW mute */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_MUTE_SWITCH,
+		index, private->dim_mute[SCARLETT2_BUTTON_MUTE]);
+	if (err < 0)
+		return err;
+
+	/* Send SW/HW switch change to the device */
+	return scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_SW_HW_SWITCH,
+					index, val);
+}
+
+static int scarlett2_sw_hw_enum_ctl_put(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int ctl_index = elem->control;
+	int index = line_out_remap(private, ctl_index);
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->vol_sw_hw_switch[index];
+	val = !!ucontrol->value.enumerated.item[0];
+
+	if (oval == val)
+		return 0;
+
+	err = scarlett2_sw_hw_change(mixer, ctl_index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_sw_hw_enum_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_sw_hw_enum_ctl_info,
+	.get  = scarlett2_sw_hw_enum_ctl_get,
+	.put  = scarlett2_sw_hw_enum_ctl_put,
+};
+
+/*** Line Level/Instrument Level Switch Controls ***/
+
+static int scarlett2_update_input_level(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	private->input_level_updated = 0;
+
+	if (!info->level_input_count)
+		return 0;
+
+	return scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_LEVEL_SWITCH,
+		info->level_input_count + info->level_input_first,
+		private->level_switch);
+}
+
+static int scarlett2_level_enum_ctl_info(struct snd_kcontrol *kctl,
+					 struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const values[2] = {
+		"Line", "Inst"
+	};
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_autogain_updated(mixer);
+	if (err < 0)
+		return err;
+
+	return snd_ctl_enum_info(uinfo, 1, 2, values);
+}
+
+static int scarlett2_level_enum_ctl_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int index = elem->control + info->level_input_first;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_level_updated) {
+		err = scarlett2_update_input_level(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] = scarlett2_decode_muteable(
+		private->level_switch[index]);
+	return 0;
+}
+
+static int scarlett2_level_enum_ctl_put(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int index = elem->control + info->level_input_first;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->level_switch[index];
+	val = !!ucontrol->value.enumerated.item[0];
+
+	if (oval == val)
+		return 0;
+
+	private->level_switch[index] = val;
+
+	/* To set the Gen 4 muteable controls, bit 1 gets set instead */
+	if (private->config_set->items[SCARLETT2_CONFIG_LEVEL_SWITCH].mute)
+		val = (!val) | 0x02;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_LEVEL_SWITCH,
+				       index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_level_enum_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_level_enum_ctl_info,
+	.get  = scarlett2_level_enum_ctl_get,
+	.put  = scarlett2_level_enum_ctl_put,
+};
+
+/*** Pad Switch Controls ***/
+
+static int scarlett2_update_input_pad(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	private->input_pad_updated = 0;
+
+	if (!info->pad_input_count)
+		return 0;
+
+	return scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_PAD_SWITCH,
+		info->pad_input_count, private->pad_switch);
+}
+
+static int scarlett2_pad_ctl_get(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_pad_updated) {
+		err = scarlett2_update_input_pad(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] =
+		private->pad_switch[elem->control];
+	return 0;
+}
+
+static int scarlett2_pad_ctl_put(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->pad_switch[index];
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->pad_switch[index] = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_PAD_SWITCH,
+				       index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_pad_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_pad_ctl_get,
+	.put  = scarlett2_pad_ctl_put,
+};
+
+/*** Air Switch Controls ***/
+
+static int scarlett2_update_input_air(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	private->input_air_updated = 0;
+
+	if (!info->air_input_count)
+		return 0;
+
+	return scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_AIR_SWITCH,
+		info->air_input_count, private->air_switch);
+}
+
+static int scarlett2_air_ctl_get(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_air_updated) {
+		err = scarlett2_update_input_air(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->air_switch[elem->control];
+	return 0;
+}
+
+static int scarlett2_air_ctl_put(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->air_switch[index];
+	val = ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->air_switch[index] = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_AIR_SWITCH,
+				       index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_air_with_drive_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const values[3] = {
+		"Off", "Presence", "Presence + Drive"
+	};
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_autogain_updated(mixer);
+	if (err < 0)
+		return err;
+
+	return snd_ctl_enum_info(uinfo, 1, 3, values);
+}
+
+static const struct snd_kcontrol_new scarlett2_air_ctl[2] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "",
+		.info = snd_ctl_boolean_mono_info,
+		.get  = scarlett2_air_ctl_get,
+		.put  = scarlett2_air_ctl_put,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "",
+		.info = scarlett2_air_with_drive_ctl_info,
+		.get  = scarlett2_air_ctl_get,
+		.put  = scarlett2_air_ctl_put,
+	}
+};
+
+/*** DSP Switch Control ***/
+
+static int scarlett2_update_input_dsp(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	private->input_dsp_updated = 0;
+
+	if (!info->dsp_input_count)
+		return 0;
+
+	return scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_DSP_SWITCH,
+		info->dsp_input_count, private->dsp_switch);
+}
+
+static int scarlett2_dsp_ctl_get(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_dsp_updated) {
+		err = scarlett2_update_input_dsp(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->dsp_switch[elem->control];
+	return 0;
+}
+
+static int scarlett2_dsp_ctl_put(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->dsp_switch[index];
+	val = ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->dsp_switch[index] = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_DSP_SWITCH,
+				       index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_dsp_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_autogain_disables_ctl_info,
+	.get  = scarlett2_dsp_ctl_get,
+	.put  = scarlett2_dsp_ctl_put,
+};
+
+/*** DSP Compressor Parameter Controls ***/
+
+static int scarlett2_update_compressor_values(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int err, i, j;
+
+	if (!info->dsp_input_count)
+		return 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_COMPRESSOR_PARAMS,
+		SCARLETT2_COMPRESSOR_PARAM_COUNT * info->dsp_input_count,
+		private->compressor_values);
+
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < SCARLETT2_COMPRESSOR_PARAM_COUNT; i++) {
+		const struct compressor_param *param = &compressor_params[i];
+
+		for (j = 0; j < info->dsp_input_count; j++) {
+			int idx = i + j * SCARLETT2_COMPRESSOR_PARAM_COUNT;
+			int val = private->compressor_values[idx];
+
+			val >>= param->scale_bits;
+			val = clamp(val, param->min, param->max);
+			private->compressor_values[idx] = val;
+		}
+	}
+
+	return 0;
+}
+
+static int scarlett2_compressor_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] =
+		private->compressor_values[elem->control];
+	return 0;
+}
+
+static int scarlett2_compressor_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int channel = index / SCARLETT2_COMPRESSOR_PARAM_COUNT;
+	int param_index = index % SCARLETT2_COMPRESSOR_PARAM_COUNT;
+	const struct compressor_param *param = &compressor_params[param_index];
+	int oval, val, err;
+	s32 scaled_val;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->compressor_values[index];
+	val = ucontrol->value.integer.value[0];
+	if (oval == val)
+		return 0;
+
+	private->compressor_values[index] = val;
+
+	scaled_val = val << param->scale_bits;
+
+	/* Send change to the device */
+
+	/* The channel needs to be put in the parameter buffer index
+	 * field (param_buf_addr + 1); the value field isn't used in
+	 * this case.
+	 */
+	err = scarlett2_usb_set_data(
+		mixer, private->config_set->param_buf_addr + 1, 1, channel);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_COMPRESSOR_PARAMS, index, scaled_val);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_compressor_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	int control = elem->control % SCARLETT2_COMPRESSOR_PARAM_COUNT;
+
+	uinfo->type = compressor_params[control].type;
+	uinfo->count = 1;
+	uinfo->value.integer.min = compressor_params[control].min;
+	uinfo->value.integer.max = compressor_params[control].max;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_compressor_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "",
+	.info = scarlett2_compressor_ctl_info,
+	.get  = scarlett2_compressor_ctl_get,
+	.put  = scarlett2_compressor_ctl_put,
+};
+
+/*** DSP Pre-Compressor and PEQ Filter Controls ***/
+
+static int scarlett2_precomp_flt_switch_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] = private->precomp_flt_switch[elem->control];
+
+	return 0;
+}
+
+static int scarlett2_peq_flt_switch_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] =
+		private->peq_flt_switch[elem->control];
+
+	return 0;
+}
+
+static int scarlett2_precomp_flt_switch_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->precomp_flt_switch[elem->control];
+	val = ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->precomp_flt_switch[elem->control] = val;
+
+	/* Send change to the device */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_PRECOMP_FLT_SWITCH,
+		elem->control, val);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_peq_flt_switch_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->peq_flt_switch[elem->control];
+	val = ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->peq_flt_switch[elem->control] = val;
+
+	/* Send change to the device */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_PEQ_FLT_SWITCH,
+		elem->control, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_precomp_flt_switch_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_precomp_flt_switch_ctl_get,
+	.put  = scarlett2_precomp_flt_switch_ctl_put,
+};
+
+static const struct snd_kcontrol_new scarlett2_peq_flt_switch_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_peq_flt_switch_ctl_get,
+	.put  = scarlett2_peq_flt_switch_ctl_put,
+};
+
+static int scarlett2_update_filter_values(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int err, i, j, k, src_idx, dst_idx;
+	s32 peq_flt_values[SCARLETT2_DSP_SWITCH_MAX *
+			   SCARLETT2_PEQ_FLT_SLOTS_MAX *
+			   SCARLETT2_BIQUAD_COEFFS];
+
+	if (!info->dsp_input_count)
+		return 0;
+
+	/* Get filter switch values */
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_PRECOMP_FLT_SWITCH,
+		info->dsp_input_count, private->precomp_flt_switch);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_PEQ_FLT_SWITCH,
+		info->dsp_input_count, private->peq_flt_switch);
+	if (err < 0)
+		return err;
+
+	/* Get pre-compressor filter values directly */
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_PRECOMP_FLT_PARAMS,
+		info->dsp_input_count *
+			info->precomp_flt_count *
+			SCARLETT2_BIQUAD_COEFFS,
+		private->precomp_flt_values);
+
+	if (err < 0)
+		return err;
+
+	/* PEQ filter values need to be copied via buffer because of
+	 * padding after peq_flt_count up to peq_flt_total_count
+	 */
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_PEQ_FLT_PARAMS,
+		info->dsp_input_count *
+			info->peq_flt_total_count *
+			SCARLETT2_BIQUAD_COEFFS,
+		peq_flt_values);
+	if (err < 0)
+		return err;
+
+	for (i = 0, dst_idx = 0; i < info->dsp_input_count; i++) {
+		src_idx = i *
+			  info->peq_flt_total_count *
+			  SCARLETT2_BIQUAD_COEFFS;
+		for (j = 0; j < info->peq_flt_count; j++)
+			for (k = 0;
+			     k < SCARLETT2_BIQUAD_COEFFS;
+			     k++, src_idx++, dst_idx++)
+				private->peq_flt_values[dst_idx] =
+					peq_flt_values[src_idx];
+	}
+
+	return 0;
+}
+
+static int scarlett2_precomp_flt_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+	int i, idx;
+
+	for (i = 0, idx = elem->control * SCARLETT2_BIQUAD_COEFFS;
+	     i < SCARLETT2_BIQUAD_COEFFS;
+	     i++, idx++)
+		ucontrol->value.integer.value[i] =
+			private->precomp_flt_values[idx];
+
+	return 0;
+}
+
+static int scarlett2_peq_flt_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+	int i, idx;
+
+	for (i = 0, idx = elem->control * SCARLETT2_BIQUAD_COEFFS;
+	     i < SCARLETT2_BIQUAD_COEFFS;
+	     i++, idx++)
+		ucontrol->value.integer.value[i] =
+			private->peq_flt_values[idx];
+
+	return 0;
+}
+
+static int scarlett2_precomp_flt_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control * SCARLETT2_BIQUAD_COEFFS;
+	int i, oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	/* Check if any of the values have changed; if not, return */
+	for (i = 0; i < SCARLETT2_BIQUAD_COEFFS; i++) {
+		oval = private->precomp_flt_values[index + i];
+		val = ucontrol->value.integer.value[i];
+		if (oval != val)
+			break;
+	}
+
+	if (i == SCARLETT2_BIQUAD_COEFFS)
+		return 0;
+
+	/* Update the values */
+	for (i = 0; i < SCARLETT2_BIQUAD_COEFFS; i++)
+		private->precomp_flt_values[index + i] =
+			ucontrol->value.integer.value[i];
+
+	/* Send change to the device */
+	err = scarlett2_usb_set_data(
+		mixer, private->config_set->param_buf_addr, 1, index);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_usb_set_config_buf(
+		mixer, SCARLETT2_CONFIG_PRECOMP_FLT_PARAMS,
+		index, SCARLETT2_BIQUAD_COEFFS,
+		&private->precomp_flt_values[index]);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_peq_flt_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int src_index = elem->control * SCARLETT2_BIQUAD_COEFFS;
+	int dst_index = (
+		elem->control /
+		info->peq_flt_count *
+		info->peq_flt_total_count +
+		elem->control % info->peq_flt_count
+	) * SCARLETT2_BIQUAD_COEFFS;
+	int i, oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	/* Check if any of the values have changed; if not, return */
+	for (i = 0; i < SCARLETT2_BIQUAD_COEFFS; i++) {
+		oval = private->peq_flt_values[src_index + i];
+		val = ucontrol->value.integer.value[i];
+		if (oval != val)
+			break;
+	}
+
+	if (i == SCARLETT2_BIQUAD_COEFFS)
+		return 0;
+
+	/* Update the values */
+	for (i = 0; i < SCARLETT2_BIQUAD_COEFFS; i++)
+		private->peq_flt_values[src_index + i] =
+			ucontrol->value.integer.value[i];
+
+	/* Send change to the device */
+	err = scarlett2_usb_set_data(
+		mixer, private->config_set->param_buf_addr, 1, dst_index);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_usb_set_config_buf(
+		mixer, SCARLETT2_CONFIG_PEQ_FLT_PARAMS,
+		dst_index, SCARLETT2_BIQUAD_COEFFS,
+		&private->peq_flt_values[src_index]);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_flt_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = SCARLETT2_BIQUAD_COEFFS;
+	uinfo->value.integer.min = INT_MIN;
+	uinfo->value.integer.max = INT_MAX;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_precomp_flt_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "",
+	.info = scarlett2_flt_ctl_info,
+	.get  = scarlett2_precomp_flt_ctl_get,
+	.put  = scarlett2_precomp_flt_ctl_put,
+};
+
+static const struct snd_kcontrol_new scarlett2_peq_flt_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "",
+	.info = scarlett2_flt_ctl_info,
+	.get  = scarlett2_peq_flt_ctl_get,
+	.put  = scarlett2_peq_flt_ctl_put,
+};
+
+/*** Input Mute Switch Controls ***/
+
+static int scarlett2_update_input_mute(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	private->input_mute_updated = 0;
+
+	if (!info->mute_input_count)
+		return 0;
+
+	return scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_INPUT_MUTE_SWITCH,
+		info->mute_input_count, private->input_mute_switch);
+}
+
+static int scarlett2_input_mute_ctl_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->input_mute_updated) {
+		err = scarlett2_update_input_mute(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] =
+		private->input_mute_switch[elem->control];
+	return 0;
+}
+
+static int scarlett2_input_mute_ctl_put(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->input_mute_switch[index];
+	val = ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->input_mute_switch[index] = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_INPUT_MUTE_SWITCH,
+			index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_input_mute_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_autogain_disables_ctl_info,
+	.get  = scarlett2_input_mute_ctl_get,
+	.put  = scarlett2_input_mute_ctl_put,
+};
+
+/*** Phantom Switch Controls ***/
+
+static int scarlett2_update_input_phantom(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int err;
+
+	private->input_phantom_updated = 0;
+
+	if (!info->phantom_count)
+		return 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_PHANTOM_SWITCH,
+		info->phantom_count, private->phantom_switch);
+	if (err < 0)
+		return err;
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_PHANTOM_PERSISTENCE)) {
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_PHANTOM_PERSISTENCE,
+			1, &private->phantom_persistence);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/* Check if phantom power on the given input is currently changing state */
+static int scarlett2_phantom_is_switching(
+	struct scarlett2_data *private, int line_num)
+{
+	const struct scarlett2_device_info *info = private->info;
+	int index = line_num / info->inputs_per_phantom;
+
+	return !!(private->phantom_switch[index] & 0x02);
+}
+
+/* Update autogain controls' access mode when phantom power changes state */
+static void scarlett2_phantom_update_access(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	/* Disable autogain controls if phantom power is changing state */
+	for (i = 0; i < info->gain_input_count; i++) {
+		int val = !scarlett2_phantom_is_switching(private, i);
+
+		scarlett2_set_ctl_access(private->autogain_ctls[i], val);
+	}
+}
+
+/* Notify of access mode change for autogain which can't be enabled
+ * while phantom power is changing.
+ */
+static void scarlett2_phantom_notify_access(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	for (i = 0; i < info->gain_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->autogain_ctls[i]->id);
+}
+
+/* Call scarlett2_update_input_phantom() and
+ * scarlett2_phantom_update_access() if input_phantom_updated is set.
+ */
+static int scarlett2_check_input_phantom_updated(
+	struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	if (!private->input_phantom_updated)
+		return 0;
+
+	err = scarlett2_update_input_phantom(mixer);
+	if (err < 0)
+		return err;
+
+	scarlett2_phantom_update_access(mixer);
+
+	return 0;
+}
+
+static int scarlett2_phantom_ctl_get(struct snd_kcontrol *kctl,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_input_phantom_updated(mixer);
+	if (err < 0)
+		return err;
+
+	ucontrol->value.integer.value[0] = scarlett2_decode_muteable(
+		private->phantom_switch[elem->control]);
+	return 0;
+}
+
+static int scarlett2_phantom_ctl_put(struct snd_kcontrol *kctl,
+				     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_check_put_during_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	oval = private->phantom_switch[index];
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->phantom_switch[index] = val;
+
+	/* To set the Gen 4 muteable controls, bit 1 gets set */
+	if (private->config_set->items[SCARLETT2_CONFIG_PHANTOM_SWITCH].mute)
+		val = (!val) | 0x02;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_PHANTOM_SWITCH,
+				       index + info->phantom_first, val);
+	scarlett2_phantom_update_access(mixer);
+	scarlett2_phantom_notify_access(mixer);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_phantom_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_autogain_disables_ctl_info,
+	.get  = scarlett2_phantom_ctl_get,
+	.put  = scarlett2_phantom_ctl_put,
+};
+
+/*** Phantom Persistence Control ***/
+
+static int scarlett2_phantom_persistence_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] = private->phantom_persistence;
+	return 0;
+}
+
+static int scarlett2_phantom_persistence_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->phantom_persistence;
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->phantom_persistence = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_PHANTOM_PERSISTENCE, index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_phantom_persistence_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_phantom_persistence_ctl_get,
+	.put  = scarlett2_phantom_persistence_ctl_put,
+};
+
+/*** Speaker Switching Control ***/
+
+static int scarlett2_update_monitor_other(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int err;
+
+	/* monitor_other_enable[0] enables speaker switching
+	 * monitor_other_enable[1] enables talkback
+	 */
+	u8 monitor_other_enable[2];
+
+	/* monitor_other_switch[0] activates the alternate speakers
+	 * monitor_other_switch[1] activates talkback
+	 */
+	u8 monitor_other_switch[2];
+
+	private->monitor_other_updated = 0;
+
+	/* if it doesn't do speaker switching then it also doesn't do
+	 * talkback
+	 */
+	if (!info->has_speaker_switching)
+		return 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_MONITOR_OTHER_ENABLE,
+		2, monitor_other_enable);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_MONITOR_OTHER_SWITCH,
+		2, monitor_other_switch);
+	if (err < 0)
+		return err;
+
+	if (!monitor_other_enable[0])
+		private->speaker_switching_switch = 0;
+	else
+		private->speaker_switching_switch = monitor_other_switch[0] + 1;
+
+	if (info->has_talkback) {
+		u16 bitmap;
+		int i;
+
+		if (!monitor_other_enable[1])
+			private->talkback_switch = 0;
+		else
+			private->talkback_switch = monitor_other_switch[1] + 1;
+
+		err = scarlett2_usb_get_config(mixer,
+					       SCARLETT2_CONFIG_TALKBACK_MAP,
+					       1, &bitmap);
+		if (err < 0)
+			return err;
+		for (i = 0; i < private->num_mix_out; i++, bitmap >>= 1)
+			private->talkback_map[i] = bitmap & 1;
+	}
+
+	return 0;
+}
+
+static int scarlett2_speaker_switch_enum_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const values[3] = {
+		"Off", "Main", "Alt"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, 3, values);
+}
+
+static int scarlett2_speaker_switch_enum_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->monitor_other_updated) {
+		err = scarlett2_update_monitor_other(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] = private->speaker_switching_switch;
+	return 0;
+}
+
+/* when speaker switching gets enabled, switch the main/alt speakers
+ * to HW volume and disable those controls
+ */
+static int scarlett2_speaker_switch_enable(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	int i, err;
+
+	for (i = 0; i < 4; i++) {
+		int index = line_out_remap(private, i);
+
+		/* switch the main/alt speakers to HW volume */
+		if (!private->vol_sw_hw_switch[index]) {
+			err = scarlett2_sw_hw_change(private->mixer, i, 1);
+			if (err < 0)
+				return err;
+		}
+
+		/* disable the line out SW/HW switch */
+		scarlett2_sw_hw_ctl_ro(private, i);
+		snd_ctl_notify(card,
+			       SNDRV_CTL_EVENT_MASK_VALUE |
+				 SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->sw_hw_ctls[i]->id);
+	}
+
+	/* when the next monitor-other notify comes in, update the mux
+	 * configuration
+	 */
+	private->speaker_switching_switched = 1;
+
+	return 0;
+}
+
+/* when speaker switching gets disabled, reenable the hw/sw controls
+ * and invalidate the routing
+ */
+static void scarlett2_speaker_switch_disable(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	int i;
+
+	/* enable the line out SW/HW switch */
+	for (i = 0; i < 4; i++) {
+		scarlett2_sw_hw_ctl_rw(private, i);
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+			       &private->sw_hw_ctls[i]->id);
+	}
+
+	/* when the next monitor-other notify comes in, update the mux
+	 * configuration
+	 */
+	private->speaker_switching_switched = 1;
+}
+
+static int scarlett2_speaker_switch_enum_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->speaker_switching_switch;
+	val = min(ucontrol->value.enumerated.item[0], 2U);
+
+	if (oval == val)
+		return 0;
+
+	private->speaker_switching_switch = val;
+
+	/* enable/disable speaker switching */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_MONITOR_OTHER_ENABLE,
+		0, !!val);
+	if (err < 0)
+		return err;
+
+	/* if speaker switching is enabled, select main or alt */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_MONITOR_OTHER_SWITCH,
+		0, val == 2);
+	if (err < 0)
+		return err;
+
+	/* update controls if speaker switching gets enabled or disabled */
+	if (!oval && val)
+		err = scarlett2_speaker_switch_enable(mixer);
+	else if (oval && !val)
+		scarlett2_speaker_switch_disable(mixer);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_speaker_switch_enum_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_speaker_switch_enum_ctl_info,
+	.get  = scarlett2_speaker_switch_enum_ctl_get,
+	.put  = scarlett2_speaker_switch_enum_ctl_put,
+};
+
+static int scarlett2_add_speaker_switch_ctl(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	if (!info->has_speaker_switching)
+		return 0;
+
+	return scarlett2_add_new_ctl(
+		mixer, &scarlett2_speaker_switch_enum_ctl,
+		0, 1, "Speaker Switching Playback Enum",
+		&private->speaker_switching_ctl);
+}
+
+/*** Talkback and Talkback Map Controls ***/
+
+static int scarlett2_talkback_enum_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const values[3] = {
+		"Disabled", "Off", "On"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, 3, values);
+}
+
+static int scarlett2_talkback_enum_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->monitor_other_updated) {
+		err = scarlett2_update_monitor_other(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] = private->talkback_switch;
+	return 0;
+}
+
+static int scarlett2_talkback_enum_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->talkback_switch;
+	val = min(ucontrol->value.enumerated.item[0], 2U);
+
+	if (oval == val)
+		return 0;
+
+	private->talkback_switch = val;
+
+	/* enable/disable talkback */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_MONITOR_OTHER_ENABLE,
+		1, !!val);
+	if (err < 0)
+		return err;
+
+	/* if talkback is enabled, select main or alt */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_MONITOR_OTHER_SWITCH,
+		1, val == 2);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_talkback_enum_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_talkback_enum_ctl_info,
+	.get  = scarlett2_talkback_enum_ctl_get,
+	.put  = scarlett2_talkback_enum_ctl_put,
+};
+
+static int scarlett2_talkback_map_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+
+	ucontrol->value.integer.value[0] = private->talkback_map[index];
+
+	return 0;
+}
+
+static int scarlett2_talkback_map_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err, i;
+	u16 bitmap = 0;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->talkback_map[index];
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->talkback_map[index] = val;
+
+	for (i = 0; i < private->num_mix_out; i++)
+		bitmap |= private->talkback_map[i] << i;
+
+	/* Send updated bitmap to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_TALKBACK_MAP,
+				       0, bitmap);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_talkback_map_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_talkback_map_ctl_get,
+	.put  = scarlett2_talkback_map_ctl_put,
+};
+
+static int scarlett2_add_talkback_ctls(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int err, i;
+	char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+
+	if (!info->has_talkback)
+		return 0;
+
+	err = scarlett2_add_new_ctl(
+		mixer, &scarlett2_talkback_enum_ctl,
+		0, 1, "Talkback Playback Enum",
+		&private->talkback_ctl);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < private->num_mix_out; i++) {
+		snprintf(s, sizeof(s),
+			 "Talkback Mix %c Playback Switch", i + 'A');
+		err = scarlett2_add_new_ctl(mixer, &scarlett2_talkback_map_ctl,
+					    i, 1, s, NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/*** Dim/Mute Controls ***/
+
+static int scarlett2_dim_mute_ctl_get(struct snd_kcontrol *kctl,
+				      struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->dim_mute_updated) {
+		err = scarlett2_update_dim_mute(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->dim_mute[elem->control];
+	return 0;
+}
+
+static int scarlett2_dim_mute_ctl_put(struct snd_kcontrol *kctl,
+				      struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err, i;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->dim_mute[index];
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->dim_mute[index] = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_DIM_MUTE,
+				       index, val);
+	if (index == SCARLETT2_BUTTON_MUTE)
+		for (i = 0; i < private->num_line_out; i++) {
+			int line_index = line_out_remap(private, i);
+
+			if (private->vol_sw_hw_switch[line_index]) {
+				private->mute_switch[line_index] = val;
+				snd_ctl_notify(mixer->chip->card,
+					       SNDRV_CTL_EVENT_MASK_VALUE,
+					       &private->mute_ctls[i]->id);
+			}
+		}
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_dim_mute_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_dim_mute_ctl_get,
+	.put  = scarlett2_dim_mute_ctl_put
+};
+
+/*** Vocaster Speaker/Headphone Mute Controls ***/
+
+static int scarlett2_sp_hp_mute_ctl_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] =
+		!!(private->sp_hp_mute & (1 << elem->control));
+
+	return 0;
+}
+
+static int scarlett2_sp_hp_mute_ctl_put(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	val = private->sp_hp_mute;
+
+	if (ucontrol->value.integer.value[0])
+		val |= (1 << index);
+	else
+		val &= ~(1 << index);
+
+	if (val == private->sp_hp_mute)
+		return 0;
+
+	private->sp_hp_mute = val;
+
+	/* Send change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_SP_HP_MUTE,
+				       0, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_sp_hp_mute_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_sp_hp_mute_ctl_get,
+	.put  = scarlett2_sp_hp_mute_ctl_put
+};
+
+/*** Create the analogue output controls ***/
+
+static int scarlett2_add_line_out_ctls(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int err, i;
+	char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+
+	/* Add R/O HW volume control */
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_MASTER_VOLUME)) {
+		snprintf(s, sizeof(s), "Master HW Playback Volume");
+		err = scarlett2_add_new_ctl(mixer,
+					    &scarlett2_master_volume_ctl,
+					    0, 1, s, &private->master_vol_ctl);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add R/O headphone volume control */
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_HEADPHONE_VOLUME)) {
+		snprintf(s, sizeof(s), "Headphone Playback Volume");
+		err = scarlett2_add_new_ctl(mixer,
+					    &scarlett2_headphone_volume_ctl,
+					    0, 1, s,
+					    &private->headphone_vol_ctl);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add Vocaster speaker/headphone mute controls */
+	if (private->info->sp_hp_mute_names)
+		for (i = 0; private->info->sp_hp_mute_names[i]; i++) {
+			err = scarlett2_add_new_ctl(
+				mixer, &scarlett2_sp_hp_mute_ctl,
+				i, 1, private->info->sp_hp_mute_names[i],
+				NULL);
+			if (err < 0)
+				return err;
+		}
+
+	/* Remaining controls are only applicable if the device
+	 * has per-channel line-out volume controls.
+	 */
+	if (!scarlett2_has_config_item(private,
+				       SCARLETT2_CONFIG_LINE_OUT_VOLUME))
+		return 0;
+
+	/* Add volume controls */
+	for (i = 0; i < private->num_line_out; i++) {
+		int index = line_out_remap(private, i);
+
+		/* Fader */
+		if (info->line_out_descrs[i])
+			snprintf(s, sizeof(s),
+				 "Line %02d (%s) Playback Volume",
+				 i + 1, info->line_out_descrs[i]);
+		else
+			snprintf(s, sizeof(s),
+				 "Line %02d Playback Volume",
+				 i + 1);
+		err = scarlett2_add_new_ctl(mixer,
+					    &scarlett2_line_out_volume_ctl,
+					    i, 1, s, &private->vol_ctls[i]);
+		if (err < 0)
+			return err;
+
+		/* Mute Switch */
+		snprintf(s, sizeof(s),
+			 "Line %02d Mute Playback Switch",
+			 i + 1);
+		err = scarlett2_add_new_ctl(mixer,
+					    &scarlett2_mute_ctl,
+					    i, 1, s,
+					    &private->mute_ctls[i]);
+		if (err < 0)
+			return err;
+
+		/* SW/HW Switch */
+		if (scarlett2_has_config_item(private,
+					      SCARLETT2_CONFIG_SW_HW_SWITCH)) {
+
+			/* Make the fader and mute controls read-only if the
+			 * SW/HW switch is set to HW
+			 */
+			if (private->vol_sw_hw_switch[index])
+				scarlett2_vol_ctl_set_writable(mixer, i, 0);
+
+			scnprintf(s, sizeof(s),
+				  "Line Out %02d Volume Control Playback Enum",
+				  i + 1);
+			err = scarlett2_add_new_ctl(mixer,
+						    &scarlett2_sw_hw_enum_ctl,
+						    i, 1, s,
+						    &private->sw_hw_ctls[i]);
+			if (err < 0)
+				return err;
+
+			/* Make the switch read-only if the line is
+			 * involved in speaker switching
+			 */
+			if (private->speaker_switching_switch && i < 4)
+				scarlett2_sw_hw_ctl_ro(private, i);
+		}
+	}
+
+	/* Add dim/mute controls */
+	if (scarlett2_has_config_item(private, SCARLETT2_CONFIG_DIM_MUTE))
+		for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++) {
+			err = scarlett2_add_new_ctl(
+				mixer, &scarlett2_dim_mute_ctl,
+				i, 1, scarlett2_dim_mute_names[i],
+				&private->dim_mute_ctls[i]);
+			if (err < 0)
+				return err;
+		}
+
+	return 0;
+}
+
+/*** Create the analogue input controls ***/
+
+static int scarlett2_add_dsp_ctls(struct usb_mixer_interface *mixer, int i)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int j, err;
+	char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	const char *compr_fmt = "Line In %d Compressor %s";
+	const char *flt_switch_fmt = "Line In %d %s Filter Enable";
+	const char *flt_fmt = "Line In %d %s Coefficients %d";
+
+	/* Add compressor controls */
+	for (j = 0; j < SCARLETT2_COMPRESSOR_PARAM_COUNT; j++) {
+		const struct compressor_param *param = &compressor_params[j];
+		int idx = i * SCARLETT2_COMPRESSOR_PARAM_COUNT + j;
+
+		scnprintf(s, sizeof(s), compr_fmt, i + 1, param->name);
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_compressor_ctl,
+			i * SCARLETT2_COMPRESSOR_PARAM_COUNT + j,
+			1, s, &private->compressor_ctls[idx]);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add filter enable controls */
+	scnprintf(s, sizeof(s), flt_switch_fmt, i + 1, "Pre-Comp");
+	err = scarlett2_add_new_ctl(
+		mixer, &scarlett2_precomp_flt_switch_ctl,
+		i, 1, s, &private->precomp_flt_switch_ctls[i]);
+	if (err < 0)
+		return err;
+
+	scnprintf(s, sizeof(s), flt_switch_fmt, i + 1, "PEQ");
+	err = scarlett2_add_new_ctl(
+		mixer, &scarlett2_peq_flt_switch_ctl,
+		i, 1, s, &private->peq_flt_switch_ctls[i]);
+	if (err < 0)
+		return err;
+
+	/* Add filter coefficient controls */
+	for (j = 0; j < info->precomp_flt_count; j++) {
+		scnprintf(s, sizeof(s), flt_fmt, i + 1, "Pre-Comp", j + 1);
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_precomp_flt_ctl,
+			i * info->precomp_flt_count + j,
+			1, s, NULL);
+		if (err < 0)
+			return err;
+	}
+
+	for (j = 0; j < info->peq_flt_count; j++) {
+		scnprintf(s, sizeof(s), flt_fmt, i + 1, "PEQ", j + 1);
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_peq_flt_ctl,
+			i * info->peq_flt_count + j,
+			1, s, NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int err, i;
+	char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+	const char *fmt = "Line In %d %s Capture %s";
+	const char *fmt2 = "Line In %d-%d %s Capture %s";
+
+	/* Add input level (line/inst) controls */
+	for (i = 0; i < info->level_input_count; i++) {
+		scnprintf(s, sizeof(s), fmt, i + 1 + info->level_input_first,
+			  "Level", "Enum");
+		err = scarlett2_add_new_ctl(mixer, &scarlett2_level_enum_ctl,
+					    i, 1, s, &private->level_ctls[i]);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add input pad controls */
+	for (i = 0; i < info->pad_input_count; i++) {
+		scnprintf(s, sizeof(s), fmt, i + 1, "Pad", "Switch");
+		err = scarlett2_add_new_ctl(mixer, &scarlett2_pad_ctl,
+					    i, 1, s, &private->pad_ctls[i]);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add input air controls */
+	for (i = 0; i < info->air_input_count; i++) {
+		scnprintf(s, sizeof(s), fmt, i + 1 + info->air_input_first,
+			  "Air", info->air_option ? "Enum" : "Switch");
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_air_ctl[info->air_option],
+			i, 1, s, &private->air_ctls[i]);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add input DSP controls */
+	for (i = 0; i < info->dsp_input_count; i++) {
+		scnprintf(s, sizeof(s), fmt, i + 1, "DSP", "Switch");
+		err = scarlett2_add_new_ctl(mixer, &scarlett2_dsp_ctl,
+					    i, 1, s, &private->dsp_ctls[i]);
+		if (err < 0)
+			return err;
+
+		err = scarlett2_add_dsp_ctls(mixer, i);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add input mute controls */
+	for (i = 0; i < info->mute_input_count; i++) {
+		scnprintf(s, sizeof(s), fmt, i + 1, "Mute", "Switch");
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_input_mute_ctl,
+			i, 1, s, &private->input_mute_ctls[i]);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add input phantom controls */
+	if (info->inputs_per_phantom == 1) {
+		for (i = 0; i < info->phantom_count; i++) {
+			scnprintf(s, sizeof(s), fmt,
+				  i + 1 + info->phantom_first,
+				  "Phantom Power", "Switch");
+			err = scarlett2_add_new_ctl(
+				mixer, &scarlett2_phantom_ctl,
+				i, 1, s, &private->phantom_ctls[i]);
+			if (err < 0)
+				return err;
+		}
+	} else if (info->inputs_per_phantom > 1) {
+		for (i = 0; i < info->phantom_count; i++) {
+			int from = i * info->inputs_per_phantom + 1;
+			int to = (i + 1) * info->inputs_per_phantom;
+
+			scnprintf(s, sizeof(s), fmt2, from, to,
+				  "Phantom Power", "Switch");
+			err = scarlett2_add_new_ctl(
+				mixer, &scarlett2_phantom_ctl,
+				i, 1, s, &private->phantom_ctls[i]);
+			if (err < 0)
+				return err;
+		}
+	}
+	if (info->phantom_count &&
+	    scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_PHANTOM_PERSISTENCE)) {
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_phantom_persistence_ctl, 0, 1,
+			"Phantom Power Persistence Capture Switch", NULL);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add input select/link controls */
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_INPUT_SELECT_SWITCH)) {
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_input_select_ctl, 0, 1,
+			"Input Select Capture Enum",
+			&private->input_select_ctl);
+		if (err < 0)
+			return err;
+	}
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_INPUT_LINK_SWITCH)) {
+		for (i = 0; i < info->gain_input_count; i++) {
+			scnprintf(s, sizeof(s),
+				  "Line In %d Link Capture Switch", i + 1);
+			err = scarlett2_add_new_ctl(
+				mixer, &scarlett2_input_link_ctl,
+				i, 1, s, &private->input_link_ctls[i]);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	/* Add software-controllable input gain controls */
+	for (i = 0; i < info->gain_input_count; i++) {
+		scnprintf(s, sizeof(s), fmt, i + 1,
+			  "Gain", "Volume");
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_input_gain_ctl,
+			i, 1, s, &private->input_gain_ctls[i]);
+		if (err < 0)
+			return err;
+		private->input_gain_ctls[i]->tlv.p =
+			private->config_set->input_gain_tlv;
+
+		scnprintf(s, sizeof(s), fmt, i + 1,
+			  "Autogain", "Switch");
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_autogain_switch_ctl,
+			i, 1, s, &private->autogain_ctls[i]);
+		if (err < 0)
+			return err;
+
+		scnprintf(s, sizeof(s), fmt, i + 1,
+			  "Autogain Status", "Enum");
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_autogain_status_ctl,
+			i, 1, s, &private->autogain_status_ctls[i]);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add autogain target controls */
+	for (i = 0; i < SCARLETT2_AG_TARGET_COUNT; i++)
+		if (scarlett2_has_config_item(private,
+					      scarlett2_ag_target_configs[i])) {
+
+			scnprintf(s, sizeof(s), "Autogain %s Target",
+				  scarlett2_ag_target_names[i]);
+			err = scarlett2_add_new_ctl(
+				mixer, &scarlett2_ag_target_ctl,
+				i, 1, s, &private->ag_target_ctls[i]);
+			if (err < 0)
+				return err;
+		}
+
+	/* Add safe-mode input switch controls */
+	for (i = 0; i < info->safe_input_count; i++) {
+		scnprintf(s, sizeof(s), fmt, i + 1,
+			  "Safe", "Switch");
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_safe_ctl,
+			i, 1, s, &private->safe_ctls[i]);
+		if (err < 0)
+			return err;
+	}
+
+	/* Add PCM Input Switch control */
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_PCM_INPUT_SWITCH)) {
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_pcm_input_switch_ctl, 0, 1,
+			"PCM Input Capture Switch",
+			&private->pcm_input_switch_ctl);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/*** Mixer Volume Controls ***/
+
+static int scarlett2_update_mix(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int i, err;
+
+	private->mix_updated = 0;
+
+	for (i = 0; i < private->num_mix_out; i++) {
+		err = scarlett2_usb_get_mix(mixer, i);
+		if (err < 0)
+			return err;
+	}
+
+	return 1;
+}
+
+static int scarlett2_mixer_ctl_info(struct snd_kcontrol *kctl,
+				    struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = SCARLETT2_MIXER_MAX_VALUE;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static int scarlett2_mixer_ctl_get(struct snd_kcontrol *kctl,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->mix_updated) {
+		err = scarlett2_update_mix(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->mix[elem->control];
+	return 0;
+}
+
+static int scarlett2_mixer_ctl_put(struct snd_kcontrol *kctl,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, mix_num, err;
+	int index = elem->control;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->mix[index];
+	val = clamp(ucontrol->value.integer.value[0],
+		    0L, (long)SCARLETT2_MIXER_MAX_VALUE);
+	mix_num = index / private->num_mix_in;
+
+	if (oval == val)
+		return 0;
+
+	private->mix[index] = val;
+	err = scarlett2_usb_set_mix(mixer, mix_num);
+
+	return err < 0 ? err : 1;
+}
+
+static const DECLARE_TLV_DB_MINMAX(
+	db_scale_scarlett2_mixer,
+	SCARLETT2_MIXER_MIN_DB * 100,
+	SCARLETT2_MIXER_MAX_DB * 100
+);
+
+static const struct snd_kcontrol_new scarlett2_mixer_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett2_mixer_ctl_info,
+	.get  = scarlett2_mixer_ctl_get,
+	.put  = scarlett2_mixer_ctl_put,
+	.private_value = SCARLETT2_MIXER_MAX_DB, /* max value */
+	.tlv = { .p = db_scale_scarlett2_mixer }
+};
+
+static int scarlett2_add_mixer_ctls(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err, i, j;
+	int index;
+	char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+
+	for (i = 0, index = 0; i < private->num_mix_out; i++)
+		for (j = 0; j < private->num_mix_in; j++, index++) {
+			snprintf(s, sizeof(s),
+				 "Mix %c Input %02d Playback Volume",
+				 'A' + i, j + 1);
+			err = scarlett2_add_new_ctl(mixer, &scarlett2_mixer_ctl,
+						    index, 1, s,
+						    &private->mix_ctls[index]);
+			if (err < 0)
+				return err;
+		}
+
+	return 0;
+}
+
+/*** Direct Monitor Control ***/
+
+static int scarlett2_update_direct_monitor(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	private->direct_monitor_updated = 0;
+
+	if (!private->info->direct_monitor)
+		return 0;
+
+	return scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_DIRECT_MONITOR,
+		1, &private->direct_monitor_switch);
+}
+
+static int scarlett2_update_monitor_mix(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err, i;
+	u16 mix_values[SCARLETT2_MONITOR_MIX_MAX];
+
+	if (!private->num_monitor_mix_ctls)
+		return 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_DIRECT_MONITOR_GAIN,
+		private->num_monitor_mix_ctls, mix_values);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < private->num_monitor_mix_ctls; i++)
+		private->monitor_mix[i] = scarlett2_mixer_value_to_db(
+			mix_values[i]);
+
+	return 0;
+}
+
+static int scarlett2_direct_monitor_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->direct_monitor_updated) {
+		err = scarlett2_update_direct_monitor(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] = private->direct_monitor_switch;
+	return 0;
+}
+
+static int scarlett2_direct_monitor_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = elem->control;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->direct_monitor_switch;
+	val = min(ucontrol->value.enumerated.item[0], 2U);
+
+	if (oval == val)
+		return 0;
+
+	private->direct_monitor_switch = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_DIRECT_MONITOR, index, val);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_direct_monitor_stereo_enum_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const values[3] = {
+		"Off", "Mono", "Stereo"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, 3, values);
+}
+
+/* Direct Monitor for Solo is mono-only and only needs a boolean control
+ * Direct Monitor for 2i2 is selectable between Off/Mono/Stereo
+ */
+static const struct snd_kcontrol_new scarlett2_direct_monitor_ctl[2] = {
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "",
+		.info = snd_ctl_boolean_mono_info,
+		.get  = scarlett2_direct_monitor_ctl_get,
+		.put  = scarlett2_direct_monitor_ctl_put,
+	},
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "",
+		.info = scarlett2_direct_monitor_stereo_enum_ctl_info,
+		.get  = scarlett2_direct_monitor_ctl_get,
+		.put  = scarlett2_direct_monitor_ctl_put,
+	}
+};
+
+static int scarlett2_monitor_mix_ctl_get(struct snd_kcontrol *kctl,
+					 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] = private->monitor_mix[elem->control];
+
+	return 0;
+}
+
+static int scarlett2_monitor_mix_ctl_put(struct snd_kcontrol *kctl,
+					 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+	int index = elem->control;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->monitor_mix[index];
+	val = clamp(ucontrol->value.integer.value[0],
+		    0L, (long)SCARLETT2_MIXER_MAX_VALUE);
+
+	if (oval == val)
+		return 0;
+
+	private->monitor_mix[index] = val;
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_DIRECT_MONITOR_GAIN,
+		index, scarlett2_mixer_values[val]);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_monitor_mix_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+		  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
+	.name = "",
+	.info = scarlett2_mixer_ctl_info,
+	.get  = scarlett2_monitor_mix_ctl_get,
+	.put  = scarlett2_monitor_mix_ctl_put,
+	.private_value = SCARLETT2_MIXER_MAX_DB, /* max value */
+	.tlv = { .p = db_scale_scarlett2_mixer }
+};
+
+static int scarlett2_add_direct_monitor_ctls(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	const char *s;
+	int err, i, j, k, index;
+
+	if (!info->direct_monitor)
+		return 0;
+
+	s = info->direct_monitor == 1
+	      ? "Direct Monitor Playback Switch"
+	      : "Direct Monitor Playback Enum";
+
+	err = scarlett2_add_new_ctl(
+		mixer, &scarlett2_direct_monitor_ctl[info->direct_monitor - 1],
+		0, 1, s, &private->direct_monitor_ctl);
+	if (err < 0)
+		return err;
+
+	if (!private->num_monitor_mix_ctls)
+		return 0;
+
+	/* 1 or 2 direct monitor selections (Mono & Stereo) */
+	for (i = 0, index = 0; i < info->direct_monitor; i++) {
+		const char * const format =
+			"Monitor %sMix %c Input %02d Playback Volume";
+		const char *mix_type;
+
+		if (info->direct_monitor == 1)
+			mix_type = "";
+		else if (i == 0)
+			mix_type = "1 ";
+		else
+			mix_type = "2 ";
+
+		/* 2 Mix outputs, A/Left & B/Right */
+		for (j = 0; j < 2; j++)
+
+			/* Mix inputs */
+			for (k = 0; k < private->num_mix_in; k++, index++) {
+				char name[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+
+				scnprintf(name, sizeof(name), format,
+					  mix_type, 'A' + j, k + 1);
+
+				err = scarlett2_add_new_ctl(
+					mixer, &scarlett2_monitor_mix_ctl,
+					index, 1, name, NULL);
+				if (err < 0)
+					return err;
+			}
+	}
+
+	return 0;
+}
+
+/*** Mux Source Selection Controls ***/
+
+static int scarlett2_mux_src_enum_ctl_info(struct snd_kcontrol *kctl,
+					   struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
+	unsigned int item = uinfo->value.enumerated.item;
+	int items = private->num_mux_srcs;
+	int port_type;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
+	uinfo->count = elem->channels;
+	uinfo->value.enumerated.items = items;
+
+	if (item >= items)
+		item = uinfo->value.enumerated.item = items - 1;
+
+	for (port_type = 0;
+	     port_type < SCARLETT2_PORT_TYPE_COUNT;
+	     port_type++) {
+		if (item < port_count[port_type][SCARLETT2_PORT_IN]) {
+			const struct scarlett2_port *port =
+				&scarlett2_ports[port_type];
+
+			if (port_type == SCARLETT2_PORT_TYPE_MIX &&
+			    item >= private->num_mix_out)
+				scnprintf(uinfo->value.enumerated.name,
+					  sizeof(uinfo->value.enumerated.name),
+					  port->dsp_src_descr,
+					  item - private->num_mix_out + 1);
+			else
+				scnprintf(uinfo->value.enumerated.name,
+					  sizeof(uinfo->value.enumerated.name),
+					  port->src_descr,
+					  item + port->src_num_offset);
+
+			return 0;
+		}
+		item -= port_count[port_type][SCARLETT2_PORT_IN];
+	}
+
+	return -EINVAL;
+}
+
+static int scarlett2_mux_src_enum_ctl_get(struct snd_kcontrol *kctl,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = line_out_remap(private, elem->control);
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->mux_updated) {
+		err = scarlett2_usb_get_mux(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.enumerated.item[0] = private->mux[index];
+	return 0;
+}
+
+static int scarlett2_mux_src_enum_ctl_put(struct snd_kcontrol *kctl,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int index = line_out_remap(private, elem->control);
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->mux[index];
+	val = min(ucontrol->value.enumerated.item[0],
+		  private->num_mux_srcs - 1U);
+
+	if (oval == val)
+		return 0;
+
+	private->mux[index] = val;
+	err = scarlett2_usb_set_mux(mixer);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_mux_src_enum_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_mux_src_enum_ctl_info,
+	.get  = scarlett2_mux_src_enum_ctl_get,
+	.put  = scarlett2_mux_src_enum_ctl_put,
+};
+
+static int scarlett2_add_mux_enums(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
+	int port_type, channel, i;
+
+	for (i = 0, port_type = 0;
+	     port_type < SCARLETT2_PORT_TYPE_COUNT;
+	     port_type++) {
+		for (channel = 0;
+		     channel < port_count[port_type][SCARLETT2_PORT_OUT];
+		     channel++, i++) {
+			int err;
+			char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+			int channel_num = channel + 1;
+			const struct scarlett2_port *port =
+				&scarlett2_ports[port_type];
+			const char *descr = port->dst_descr;
+
+			if (port_type == SCARLETT2_PORT_TYPE_MIX &&
+			    channel >= private->num_mix_in) {
+				channel_num -= private->num_mix_in;
+				descr = port->dsp_dst_descr;
+			}
+
+			snprintf(s, sizeof(s) - 5, descr, channel_num);
+			strcat(s, " Enum");
+
+			err = scarlett2_add_new_ctl(mixer,
+						    &scarlett2_mux_src_enum_ctl,
+						    i, 1, s,
+						    &private->mux_ctls[i]);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+/*** Meter Controls ***/
+
+static int scarlett2_meter_ctl_info(struct snd_kcontrol *kctl,
+				    struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = elem->channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 4095;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static int scarlett2_meter_ctl_get(struct snd_kcontrol *kctl,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	u8 *meter_level_map = private->meter_level_map;
+	u16 meter_levels[SCARLETT2_MAX_METERS];
+	int i, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	err = scarlett2_usb_get_meter_levels(mixer, elem->channels,
+					     meter_levels);
+	if (err < 0)
+		return err;
+
+	/* copy & translate from meter_levels[] using meter_level_map[] */
+	for (i = 0; i < elem->channels; i++) {
+		int idx = meter_level_map[i];
+		int value;
+
+		if (idx == 255)
+			value = 0;
+		else
+			value = meter_levels[idx];
+
+		ucontrol->value.integer.value[i] = value;
+	}
+
+	return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_meter_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_PCM,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+	.name = "",
+	.info = scarlett2_meter_ctl_info,
+	.get  = scarlett2_meter_ctl_get
+};
+
+static int scarlett2_add_meter_ctl(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	/* devices without a mixer also don't support reporting levels */
+	if (!scarlett2_has_mixer(private))
+		return 0;
+
+	return scarlett2_add_new_ctl(mixer, &scarlett2_meter_ctl,
+				     0, private->num_mux_dsts,
+				     "Level Meter", NULL);
+}
+
+/*** MSD Controls ***/
+
+static int scarlett2_msd_ctl_get(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] = private->msd_switch;
+	return 0;
+}
+
+static int scarlett2_msd_ctl_put(struct snd_kcontrol *kctl,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->msd_switch;
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->msd_switch = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_MSD_SWITCH,
+				       0, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_msd_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_msd_ctl_get,
+	.put  = scarlett2_msd_ctl_put,
+};
+
+static int scarlett2_add_msd_ctl(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (!scarlett2_has_config_item(private, SCARLETT2_CONFIG_MSD_SWITCH))
+		return 0;
+
+	/* If MSD mode is off, hide the switch by default */
+	if (!private->msd_switch && !(mixer->chip->setup & SCARLETT2_MSD_ENABLE))
+		return 0;
+
+	/* Add MSD control */
+	return scarlett2_add_new_ctl(mixer, &scarlett2_msd_ctl,
+				     0, 1, "MSD Mode Switch", NULL);
+}
+
+/*** Standalone Control ***/
+
+static int scarlett2_standalone_ctl_get(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] = private->standalone_switch;
+	return 0;
+}
+
+static int scarlett2_standalone_ctl_put(struct snd_kcontrol *kctl,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->standalone_switch;
+	val = !!ucontrol->value.integer.value[0];
+
+	if (oval == val)
+		return 0;
+
+	private->standalone_switch = val;
+
+	/* Send switch change to the device */
+	err = scarlett2_usb_set_config(mixer,
+				       SCARLETT2_CONFIG_STANDALONE_SWITCH,
+				       0, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_standalone_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = snd_ctl_boolean_mono_info,
+	.get  = scarlett2_standalone_ctl_get,
+	.put  = scarlett2_standalone_ctl_put,
+};
+
+static int scarlett2_add_standalone_ctl(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (!scarlett2_has_config_item(private,
+				       SCARLETT2_CONFIG_STANDALONE_SWITCH))
+		return 0;
+
+	/* Add standalone control */
+	return scarlett2_add_new_ctl(mixer, &scarlett2_standalone_ctl,
+				     0, 1, "Standalone Switch", NULL);
+}
+
+/*** Power Status ***/
+
+static int scarlett2_update_power_status(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+	u8 power_ext, power_low;
+
+	private->power_status_updated = 0;
+
+	err = scarlett2_usb_get_config(mixer, SCARLETT2_CONFIG_POWER_EXT,
+				       1, &power_ext);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_usb_get_config(mixer, SCARLETT2_CONFIG_POWER_LOW,
+				       1, &power_low);
+	if (err < 0)
+		return err;
+
+	if (power_low)
+		private->power_status = SCARLETT2_POWER_STATUS_FAIL;
+	else if (power_ext)
+		private->power_status = SCARLETT2_POWER_STATUS_EXT;
+	else
+		private->power_status = SCARLETT2_POWER_STATUS_BUS;
+
+	return 0;
+}
+
+static int scarlett2_power_status_ctl_get(struct snd_kcontrol *kctl,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->power_status_updated) {
+		err = scarlett2_update_power_status(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->power_status;
+	return 0;
+}
+
+static int scarlett2_power_status_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	static const char *const values[3] = {
+		"External", "Bus", "Fail"
+	};
+
+	return snd_ctl_enum_info(uinfo, 1, 3, values);
+}
+
+static const struct snd_kcontrol_new scarlett2_power_status_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.name = "",
+	.info = scarlett2_power_status_ctl_info,
+	.get  = scarlett2_power_status_ctl_get,
+};
+
+static int scarlett2_add_power_status_ctl(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (!scarlett2_has_config_item(private,
+				       SCARLETT2_CONFIG_POWER_EXT))
+		return 0;
+
+	/* Add power status control */
+	return scarlett2_add_new_ctl(mixer, &scarlett2_power_status_ctl,
+				     0, 1, "Power Status Card Enum",
+				     &private->power_status_ctl);
+}
+
+/*** Bluetooth Volume ***/
+
+static int scarlett2_update_bluetooth_volume(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	private->bluetooth_updated = 0;
+
+	if (!private->info->has_bluetooth)
+		return 0;
+
+	err = scarlett2_usb_get_config(mixer,
+				       SCARLETT2_CONFIG_BLUETOOTH_VOLUME,
+				       1, &private->bluetooth_volume);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static int scarlett2_bluetooth_volume_ctl_get(struct snd_kcontrol *kctl,
+					     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	if (private->bluetooth_updated) {
+		err = scarlett2_update_bluetooth_volume(mixer);
+		if (err < 0)
+			return err;
+	}
+	ucontrol->value.integer.value[0] = private->bluetooth_volume;
+	return 0;
+}
+
+static int scarlett2_bluetooth_volume_ctl_put(struct snd_kcontrol *kctl,
+					     struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->bluetooth_volume;
+	val = clamp(ucontrol->value.integer.value[0],
+		    0L, (long)SCARLETT2_MAX_BLUETOOTH_VOLUME);
+
+	if (oval == val)
+		return 0;
+
+	private->bluetooth_volume = val;
+	err = scarlett2_usb_set_config(mixer,
+				       SCARLETT2_CONFIG_BLUETOOTH_VOLUME,
+				       0, val);
+
+	return err < 0 ? err : 1;
+}
+
+static int scarlett2_bluetooth_volume_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = SCARLETT2_MAX_BLUETOOTH_VOLUME;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_bluetooth_volume_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_bluetooth_volume_ctl_info,
+	.get  = scarlett2_bluetooth_volume_ctl_get,
+	.put  = scarlett2_bluetooth_volume_ctl_put,
+};
+
+static int scarlett2_add_bluetooth_volume_ctl(
+	struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (!private->info->has_bluetooth)
+		return 0;
+
+	/* Add Bluetooth volume control */
+	return scarlett2_add_new_ctl(mixer, &scarlett2_bluetooth_volume_ctl,
+				     0, 1, "Bluetooth Capture Volume",
+				     &private->bluetooth_volume_ctl);
+}
+
+/*** Front Panel Brightness/Sleep Controls ***/
+
+static int scarlett2_update_fp(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	if (scarlett2_has_config_item(private, SCARLETT2_CONFIG_FP_BRIGHTNESS)) {
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_FP_BRIGHTNESS,
+			1, &private->fp_brightness);
+		if (err < 0)
+			return err;
+	}
+
+	if (scarlett2_has_config_item(private, SCARLETT2_CONFIG_FP_SLEEP_TIME)) {
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_FP_SLEEP_TIME,
+			1, &private->fp_sleep_time);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static const char * const scarlett2_fp_brightness_texts[] = {
+	"High", "Medium", "Low"
+};
+
+static int scarlett2_fp_brightness_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	return snd_ctl_enum_info(uinfo, 1,
+				 ARRAY_SIZE(scarlett2_fp_brightness_texts),
+				 scarlett2_fp_brightness_texts);
+}
+
+static int scarlett2_fp_brightness_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.enumerated.item[0] = private->fp_brightness;
+	return 0;
+}
+
+static int scarlett2_fp_brightness_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->fp_brightness;
+	val = min(ucontrol->value.enumerated.item[0],
+		  ARRAY_SIZE(scarlett2_fp_brightness_texts) - 1);
+
+	if (oval == val)
+		return 0;
+
+	private->fp_brightness = val;
+
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_FP_BRIGHTNESS, 0, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_fp_brightness_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "",
+	.info = scarlett2_fp_brightness_ctl_info,
+	.get  = scarlett2_fp_brightness_ctl_get,
+	.put  = scarlett2_fp_brightness_ctl_put,
+};
+
+static int scarlett2_fp_sleep_time_ctl_info(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = SCARLETT2_MAX_FP_SLEEP_TIME;
+	uinfo->value.integer.step = 1;
+	return 0;
+}
+
+static int scarlett2_fp_sleep_time_ctl_get(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.integer.value[0] = private->fp_sleep_time;
+	return 0;
+}
+
+static int scarlett2_fp_sleep_time_ctl_put(
+	struct snd_kcontrol *kctl, struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	u32 oval, val;
+	int err;
+
+	guard(mutex)(&private->data_mutex);
+
+	if (private->hwdep_in_use)
+		return -EBUSY;
+
+	oval = private->fp_sleep_time;
+	val = clamp(ucontrol->value.integer.value[0],
+		    0L, (long)SCARLETT2_MAX_FP_SLEEP_TIME);
+
+	if (oval == val)
+		return 0;
+
+	private->fp_sleep_time = val;
+
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_FP_SLEEP_TIME, 0, val);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_fp_sleep_time_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.name = "",
+	.info = scarlett2_fp_sleep_time_ctl_info,
+	.get  = scarlett2_fp_sleep_time_ctl_get,
+	.put  = scarlett2_fp_sleep_time_ctl_put,
+};
+
+static int scarlett2_add_fp_ctls(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err;
+
+	if (scarlett2_has_config_item(private, SCARLETT2_CONFIG_FP_BRIGHTNESS)) {
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_fp_brightness_ctl, 0, 1,
+			"Front Panel Brightness", NULL);
+		if (err < 0)
+			return err;
+	}
+
+	if (scarlett2_has_config_item(private, SCARLETT2_CONFIG_FP_SLEEP_TIME)) {
+		err = scarlett2_add_new_ctl(
+			mixer, &scarlett2_fp_sleep_time_ctl, 0, 1,
+			"Front Panel Sleep Time", NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/*** S/PDIF Mode Controls ***/
+
+static int scarlett2_update_spdif_mode(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err, i;
+	u8 mode;
+	const u8 *mode_values = private->info->spdif_mode_values;
+
+	if (!private->info->spdif_mode_control_name)
+		return 0;
+
+	err = scarlett2_usb_get_config(mixer, SCARLETT2_CONFIG_SPDIF_MODE,
+				       1, &mode);
+	if (err < 0)
+		return err;
+
+	private->spdif_mode = 0;
+
+	for (i = 0; *mode_values != 0xff; i++, mode_values++)
+		if (*mode_values == mode) {
+			private->spdif_mode = i;
+			break;
+		}
+
+	return 0;
+}
+
+static int scarlett2_spdif_mode_ctl_info(struct snd_kcontrol *kctl,
+					   struct snd_ctl_elem_info *uinfo)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+	const char * const *mode_texts = private->info->spdif_mode_texts;
+	int count = 0;
+
+	while (*mode_texts++)
+		count++;
+
+	return snd_ctl_enum_info(uinfo, 1, count,
+				 private->info->spdif_mode_texts);
+}
+
+static int scarlett2_spdif_mode_ctl_get(struct snd_kcontrol *kctl,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct scarlett2_data *private = elem->head.mixer->private_data;
+
+	ucontrol->value.enumerated.item[0] = private->spdif_mode;
+	return 0;
+}
+
+static int scarlett2_spdif_mode_ctl_put(struct snd_kcontrol *kctl,
+					  struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+	struct usb_mixer_interface *mixer = elem->head.mixer;
+	struct scarlett2_data *private = mixer->private_data;
+	int oval, val, err;
+	int i;
+
+	guard(mutex)(&private->data_mutex);
+
+	oval = private->spdif_mode;
+	val = ucontrol->value.enumerated.item[0];
+
+	if (val < 0)
+		return -EINVAL;
+
+	for (i = 0; i <= val; i++)
+		if (private->info->spdif_mode_values[i] == 0xff)
+			return -EINVAL;
+
+	if (oval == val)
+		return 0;
+
+	private->spdif_mode = val;
+
+	err = scarlett2_usb_set_config(
+		mixer, SCARLETT2_CONFIG_SPDIF_MODE, 0,
+		private->info->spdif_mode_values[val]);
+
+	return err < 0 ? err : 1;
+}
+
+static const struct snd_kcontrol_new scarlett2_spdif_mode_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "",
+	.info = scarlett2_spdif_mode_ctl_info,
+	.get  = scarlett2_spdif_mode_ctl_get,
+	.put  = scarlett2_spdif_mode_ctl_put,
+};
+
+static int scarlett2_add_spdif_mode_ctl(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (!private->info->spdif_mode_control_name)
+		return 0;
+
+	return scarlett2_add_new_ctl(mixer, &scarlett2_spdif_mode_ctl,
+				     0, 1,
+				     private->info->spdif_mode_control_name,
+				     NULL);
+}
+
+/*** Notification Handlers ***/
+
+/* Notify on sync change */
+static void scarlett2_notify_sync(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	private->sync_updated = 1;
+
+	snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &private->sync_ctl->id);
+}
+
+/* Notify on monitor change (Gen 2/3) */
+static void scarlett2_notify_monitor(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	int i;
+
+	if (!scarlett2_has_config_item(private, SCARLETT2_CONFIG_SW_HW_SWITCH))
+		return;
+
+	private->vol_updated = 1;
+
+	snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &private->master_vol_ctl->id);
+
+	for (i = 0; i < private->num_line_out; i++)
+		if (private->vol_sw_hw_switch[line_out_remap(private, i)])
+			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+				       &private->vol_ctls[i]->id);
+}
+
+/* Notify on volume change (Gen 4) */
+static void scarlett2_notify_volume(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	private->vol_updated = 1;
+
+	snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &private->master_vol_ctl->id);
+	snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &private->headphone_vol_ctl->id);
+}
+
+/* Notify on dim/mute change */
+static void scarlett2_notify_dim_mute(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	int i;
+
+	if (!scarlett2_has_config_item(private, SCARLETT2_CONFIG_SW_HW_SWITCH))
+		return;
+
+	private->dim_mute_updated = 1;
+
+	for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->dim_mute_ctls[i]->id);
+
+	for (i = 0; i < private->num_line_out; i++)
+		if (private->vol_sw_hw_switch[line_out_remap(private, i)])
+			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+				       &private->mute_ctls[i]->id);
+}
+
+/* Notify on input level switch change */
+static void scarlett2_notify_input_level(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	private->input_level_updated = 1;
+
+	for (i = 0; i < info->level_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->level_ctls[i]->id);
+}
+
+/* Notify on input pad switch change */
+static void scarlett2_notify_input_pad(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	private->input_pad_updated = 1;
+
+	for (i = 0; i < info->pad_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->pad_ctls[i]->id);
+}
+
+/* Notify on input air switch change */
+static void scarlett2_notify_input_air(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	private->input_air_updated = 1;
+
+	for (i = 0; i < info->air_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->air_ctls[i]->id);
+}
+
+/* Notify on input DSP switch change */
+static void scarlett2_notify_input_dsp(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	private->input_dsp_updated = 1;
+
+	for (i = 0; i < info->dsp_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->dsp_ctls[i]->id);
+}
+
+/* Notify on input mute switch change */
+static void scarlett2_notify_input_mute(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	private->input_mute_updated = 1;
+
+	for (i = 0; i < info->mute_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->input_mute_ctls[i]->id);
+}
+
+/* Notify on input phantom switch change */
+static void scarlett2_notify_input_phantom(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	private->input_phantom_updated = 1;
+
+	for (i = 0; i < info->phantom_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->phantom_ctls[i]->id);
+
+	scarlett2_phantom_notify_access(mixer);
+}
+
+/* Notify on "input other" change (level/pad/air/phantom) */
+static void scarlett2_notify_input_other(struct usb_mixer_interface *mixer)
+{
+	scarlett2_notify_input_level(mixer);
+	scarlett2_notify_input_pad(mixer);
+	scarlett2_notify_input_air(mixer);
+	scarlett2_notify_input_phantom(mixer);
+}
+
+/* Notify on input select change */
+static void scarlett2_notify_input_select(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	if (!scarlett2_has_config_item(private,
+				       SCARLETT2_CONFIG_INPUT_SELECT_SWITCH))
+		return;
+
+	private->input_select_updated = 1;
+
+	snd_ctl_notify(card,
+		       SNDRV_CTL_EVENT_MASK_VALUE | SNDRV_CTL_EVENT_MASK_INFO,
+		       &private->input_select_ctl->id);
+
+	for (i = 0; i < info->gain_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->input_link_ctls[i]->id);
+}
+
+/* Notify on input gain change */
+static void scarlett2_notify_input_gain(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	if (!info->gain_input_count)
+		return;
+
+	private->input_gain_updated = 1;
+
+	for (i = 0; i < info->gain_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->input_gain_ctls[i]->id);
+}
+
+/* Notify on autogain change */
+static void scarlett2_notify_autogain(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	if (!info->gain_input_count)
+		return;
+
+	private->autogain_updated = 1;
+
+	for (i = 0; i < info->gain_input_count; i++) {
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->autogain_ctls[i]->id);
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->autogain_status_ctls[i]->id);
+	}
+
+	for (i = 0; i < SCARLETT2_AG_TARGET_COUNT; i++)
+		if (scarlett2_has_config_item(private,
+					      scarlett2_ag_target_configs[i]))
+			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+				       &private->ag_target_ctls[i]->id);
+
+	scarlett2_autogain_notify_access(mixer);
+}
+
+/* Notify on input safe switch change */
+static void scarlett2_notify_input_safe(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	int i;
+
+	if (!info->safe_input_count)
+		return;
+
+	private->input_safe_updated = 1;
+
+	for (i = 0; i < info->safe_input_count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->safe_ctls[i]->id);
+}
+
+/* Notify on "monitor other" change (speaker switching, talkback) */
+static void scarlett2_notify_monitor_other(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+
+	private->monitor_other_updated = 1;
+
+	if (info->has_speaker_switching)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->speaker_switching_ctl->id);
+
+	if (info->has_talkback)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->talkback_ctl->id);
+
+	/* if speaker switching was recently enabled or disabled,
+	 * invalidate the dim/mute and mux enum controls
+	 */
+	if (private->speaker_switching_switched) {
+		int i;
+
+		scarlett2_notify_dim_mute(mixer);
+
+		private->speaker_switching_switched = 0;
+		private->mux_updated = 1;
+
+		for (i = 0; i < private->num_mux_dsts; i++)
+			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+				       &private->mux_ctls[i]->id);
+	}
+}
+
+/* Notify on direct monitor switch change */
+static void scarlett2_notify_direct_monitor(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	int count = private->num_mix_in * private->num_mix_out;
+	int i;
+
+	private->direct_monitor_updated = 1;
+
+	snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &private->direct_monitor_ctl->id);
+
+	if (!scarlett2_has_mixer(private))
+		return;
+
+	private->mix_updated = 1;
+
+	/* Notify of change to the mix controls */
+	for (i = 0; i < count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->mix_ctls[i]->id);
+}
+
+/* Notify on power change */
+static void scarlett2_notify_power_status(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+
+	private->power_status_updated = 1;
+
+	snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &private->power_status_ctl->id);
+}
+
+/* Notify on mux change */
+static void scarlett2_notify_mux(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	int i;
+
+	private->mux_updated = 1;
+
+	for (i = 0; i < private->num_mux_dsts; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->mux_ctls[i]->id);
+}
+
+/* Notify on PCM input switch change */
+static void scarlett2_notify_pcm_input_switch(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+
+	private->pcm_input_switch_updated = 1;
+
+	snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &private->pcm_input_switch_ctl->id);
+
+	scarlett2_notify_mux(mixer);
+}
+
+/* Notify on Bluetooth change */
+static void scarlett2_notify_bluetooth(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (!private->info->has_bluetooth)
+		return;
+
+	private->bluetooth_updated = 1;
+
+	snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+		       &private->bluetooth_volume_ctl->id);
+}
+
+/* Handle acknowledgement that a command was received; let
+ * scarlett2_usb() know that it can proceed
+ */
+static void scarlett2_notify_ack(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	/* if running == 0, ignore ACKs */
+	if (private->running)
+		complete(&private->cmd_done);
+}
+
+/* Interrupt callback */
+static void scarlett2_notify(struct urb *urb)
+{
+	struct usb_mixer_interface *mixer = urb->context;
+	int len = urb->actual_length;
+	int ustatus = urb->status;
+	u32 data;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_notification *notifications =
+		private->config_set->notifications;
+
+	if (ustatus != 0 || len != 8)
+		goto requeue;
+
+	data = le32_to_cpu(*(__le32 *)urb->transfer_buffer);
+
+	/* Ignore notifications except ACK during initialisation.
+	 * ACK is 0x00000001 on every device.
+	 */
+	if (private->running < 2)
+		data &= 1;
+
+	while (data && notifications->mask) {
+		if (data & notifications->mask) {
+			data &= ~notifications->mask;
+			if (notifications->func)
+				notifications->func(mixer);
+		}
+		notifications++;
+	}
+
+	if (data)
+		usb_audio_warn(mixer->chip,
+			       "%s: Unhandled notification: 0x%08x\n",
+			       __func__, data);
+
+requeue:
+	if (ustatus != -ENOENT &&
+	    ustatus != -ECONNRESET &&
+	    ustatus != -ESHUTDOWN) {
+		urb->dev = mixer->chip->dev;
+		usb_submit_urb(urb, GFP_ATOMIC);
+	} else {
+		complete(&private->cmd_done);
+	}
+}
+
+/*** Notification URB and Cleanup/Suspend Callbacks ***/
+
+/* Submit a URB to receive notifications from the device */
+static int scarlett2_init_notify(struct usb_mixer_interface *mixer)
+{
+	struct usb_device *dev = mixer->chip->dev;
+	struct scarlett2_data *private = mixer->private_data;
+	unsigned int pipe = usb_rcvintpipe(dev, private->bEndpointAddress);
+	void *transfer_buffer;
+	int err;
+
+	/* Already set up */
+	if (private->urb)
+		return 0;
+
+	if (usb_pipe_type_check(dev, pipe))
+		return -EINVAL;
+
+	private->urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!private->urb)
+		return -ENOMEM;
+
+	transfer_buffer = kmalloc(private->wMaxPacketSize, GFP_KERNEL);
+	if (!transfer_buffer) {
+		usb_free_urb(private->urb);
+		private->urb = NULL;
+		return -ENOMEM;
+	}
+
+	usb_fill_int_urb(private->urb, dev, pipe,
+			 transfer_buffer, private->wMaxPacketSize,
+			 scarlett2_notify, mixer, private->bInterval);
+
+	reinit_completion(&private->cmd_done);
+
+	err = usb_submit_urb(private->urb, GFP_KERNEL);
+	if (err) {
+		kfree(transfer_buffer);
+		usb_free_urb(private->urb);
+		private->urb = NULL;
+	}
+
+	return err;
+}
+
+static void scarlett2_cleanup_urb(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (!private->urb)
+		return;
+
+	usb_kill_urb(private->urb);
+	kfree(private->urb->transfer_buffer);
+	usb_free_urb(private->urb);
+	private->urb = NULL;
+}
+
+static void scarlett2_private_free(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	cancel_delayed_work_sync(&private->work);
+	scarlett2_cleanup_urb(mixer);
+	kfree(private);
+	mixer->private_data = NULL;
+}
+
+static void scarlett2_private_suspend(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (cancel_delayed_work_sync(&private->work))
+		scarlett2_config_save_nopm(private->mixer);
+
+	scarlett2_cleanup_urb(mixer);
+}
+
+/*** Initialisation ***/
+
+/* Select the config_set matching the running firmware version.
+ *
+ * The device info's config_sets array is ordered by ascending
+ * from_firmware_version; pick the last entry whose version is <= the
+ * running firmware version. If the running firmware is older than the
+ * first entry's from_firmware_version (i.e. older than the driver's
+ * minimum supported version for this device), the first entry's
+ * config_set is selected anyway so firmware updates can still be done
+ * (requires only the ACK handler), but the usual mixer controls
+ * aren't created.
+ */
+static void scarlett2_resolve_config_set(struct scarlett2_data *private)
+{
+	const struct scarlett2_config_set_entry *entry =
+		private->info->config_sets;
+
+	private->config_set = entry->config_set;
+	for (entry++; entry->config_set; entry++)
+		if (entry->from_firmware_version <= private->firmware_version)
+			private->config_set = entry->config_set;
+}
+
+static void scarlett2_count_io(struct scarlett2_data *private)
+{
+	const struct scarlett2_device_info *info = private->info;
+	const struct scarlett2_config_set *config_set = private->config_set;
+	const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
+	int port_type, srcs = 0, dsts = 0, i;
+
+	/* Count the number of mux sources and destinations */
+	for (port_type = 0;
+	     port_type < SCARLETT2_PORT_TYPE_COUNT;
+	     port_type++) {
+		srcs += port_count[port_type][SCARLETT2_PORT_IN];
+		dsts += port_count[port_type][SCARLETT2_PORT_OUT];
+	}
+
+	private->num_mux_srcs = srcs;
+	private->num_mux_dsts = dsts;
+
+	/* Mixer inputs are mux outputs and vice versa.
+	 * Scarlett Gen 4 DSP I/O uses SCARLETT2_PORT_TYPE_MIX but
+	 * doesn't have mixer controls.
+	 */
+	private->num_mix_in =
+		port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_OUT] -
+			info->dsp_count;
+
+	private->num_mix_out =
+		port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_IN] -
+			info->dsp_count;
+
+	/* Number of analogue line outputs */
+	private->num_line_out =
+		port_count[SCARLETT2_PORT_TYPE_ANALOGUE][SCARLETT2_PORT_OUT];
+
+	/* Number of monitor mix controls */
+	private->num_monitor_mix_ctls =
+		info->direct_monitor * 2 * private->num_mix_in;
+
+	/* Number of autogain status texts */
+	if (config_set->autogain_status_texts) {
+		const char * const *texts = config_set->autogain_status_texts;
+
+		for (i = 0; texts[i]; i++)
+			;
+		private->num_autogain_status_texts = i;
+	}
+}
+
+/* Look through the interface descriptors for the Focusrite Control
+ * interface (bInterfaceClass = 255 Vendor Specific Class) and set
+ * bInterfaceNumber, bEndpointAddress, wMaxPacketSize, and bInterval
+ * in private
+ */
+static int scarlett2_find_fc_interface(struct usb_device *dev,
+				       struct scarlett2_data *private)
+{
+	struct usb_host_config *config = dev->actconfig;
+	int i;
+
+	for (i = 0; i < config->desc.bNumInterfaces; i++) {
+		struct usb_interface *intf = config->interface[i];
+		struct usb_interface_descriptor *desc =
+			&intf->altsetting[0].desc;
+		struct usb_endpoint_descriptor *epd;
+
+		if (desc->bInterfaceClass != 255)
+			continue;
+		if (desc->bNumEndpoints < 1)
+			continue;
+
+		epd = get_endpoint(intf->altsetting, 0);
+		private->bInterfaceNumber = desc->bInterfaceNumber;
+		private->bEndpointAddress = usb_endpoint_num(epd);
+		private->wMaxPacketSize = le16_to_cpu(epd->wMaxPacketSize);
+		private->bInterval = epd->bInterval;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+/* Initialise private data */
+static int scarlett2_init_private(struct usb_mixer_interface *mixer,
+				  const struct scarlett2_device_entry *entry)
+{
+	struct scarlett2_data *private =
+		kzalloc_obj(struct scarlett2_data);
+
+	if (!private)
+		return -ENOMEM;
+
+	mutex_init(&private->usb_mutex);
+	mutex_init(&private->data_mutex);
+	init_completion(&private->cmd_done);
+	INIT_DELAYED_WORK(&private->work, scarlett2_config_save_work);
+
+	mixer->private_data = private;
+	mixer->private_free = scarlett2_private_free;
+	mixer->private_suspend = scarlett2_private_suspend;
+	mixer->private_resume = scarlett2_init_notify;
+
+	private->info = entry->info;
+
+	/* Set config_set to the first entry's config_set so the
+	 * notify handler has a valid pointer while USB init runs; it
+	 * is re-resolved once the firmware version has been read.
+	 */
+	private->config_set = entry->info->config_sets[0].config_set;
+
+	private->series_name = entry->series_name;
+	private->scarlett2_seq = 0;
+	private->mixer = mixer;
+
+	return scarlett2_find_fc_interface(mixer->chip->dev, private);
+}
+
+/* Cargo cult proprietary initialisation sequence */
+static int scarlett2_usb_init(struct usb_mixer_interface *mixer)
+{
+	struct usb_device *dev = mixer->chip->dev;
+	struct scarlett2_data *private = mixer->private_data;
+	u8 step0_buf[24];
+	u8 step2_buf[84];
+	int err;
+
+	if (usb_pipe_type_check(dev, usb_sndctrlpipe(dev, 0)))
+		return -EINVAL;
+
+	/* step 0 */
+	err = scarlett2_usb_rx(dev, private->bInterfaceNumber,
+			       SCARLETT2_USB_CMD_INIT,
+			       step0_buf, sizeof(step0_buf));
+	if (err < 0)
+		return err;
+
+	/* Set up the interrupt polling for notifications.
+	 * When running is:
+	 * 0: all notifications are ignored
+	 * 1: only ACKs are handled
+	 * 2: all notifications are handled
+	 */
+	err = scarlett2_init_notify(mixer);
+	if (err < 0)
+		return err;
+
+	/* sleep for a moment in case of an outstanding ACK */
+	msleep(20);
+
+	/* start handling ACKs, but no other notifications until the
+	 * ALSA controls have been created
+	 */
+	private->running = 1;
+
+	/* step 1 */
+	private->scarlett2_seq = 1;
+	err = scarlett2_usb(mixer, SCARLETT2_USB_INIT_1, NULL, 0, NULL, 0);
+	if (err < 0)
+		return err;
+
+	/* step 2 */
+	private->scarlett2_seq = 1;
+	err = scarlett2_usb(mixer, SCARLETT2_USB_INIT_2,
+			    NULL, 0,
+			    step2_buf, sizeof(step2_buf));
+	if (err < 0)
+		return err;
+
+	/* extract 4-byte firmware version from step2_buf[8] */
+	private->firmware_version = le32_to_cpu(*(__le32 *)(step2_buf + 8));
+	usb_audio_info(mixer->chip,
+		       "Firmware version %d\n",
+		       private->firmware_version);
+
+	return 0;
+}
+
+/* Get the flash segment numbers for the App_Settings and App_Upgrade
+ * segments and put them in the private data
+ */
+static int scarlett2_get_flash_segment_nums(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err, count, i;
+
+	struct {
+		__le32 size;
+		__le32 count;
+		u8 unknown[8];
+	} __packed flash_info;
+
+	struct {
+		__le32 size;
+		__le32 flags;
+		char name[16];
+	} __packed segment_info;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_INFO_FLASH,
+			    NULL, 0,
+			    &flash_info, sizeof(flash_info));
+	if (err < 0)
+		return err;
+
+	count = le32_to_cpu(flash_info.count);
+
+	/* sanity check count */
+	if (count < SCARLETT2_SEGMENT_NUM_MIN ||
+	    count > SCARLETT2_SEGMENT_NUM_MAX + 1) {
+		usb_audio_err(mixer->chip,
+			      "invalid flash segment count: %d\n", count);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < count; i++) {
+		__le32 segment_num_req = cpu_to_le32(i);
+		int flash_segment_id;
+
+		err = scarlett2_usb(mixer, SCARLETT2_USB_INFO_SEGMENT,
+				    &segment_num_req, sizeof(segment_num_req),
+				    &segment_info, sizeof(segment_info));
+		if (err < 0) {
+			usb_audio_err(mixer->chip,
+				"failed to get flash segment info %d: %d\n",
+				i, err);
+			return err;
+		}
+
+		if (!strncmp(segment_info.name,
+			     SCARLETT2_SEGMENT_SETTINGS_NAME, 16))
+			flash_segment_id = SCARLETT2_SEGMENT_ID_SETTINGS;
+		else if (!strncmp(segment_info.name,
+				  SCARLETT2_SEGMENT_FIRMWARE_NAME, 16))
+			flash_segment_id = SCARLETT2_SEGMENT_ID_FIRMWARE;
+		else
+			continue;
+
+		private->flash_segment_nums[flash_segment_id] = i;
+		private->flash_segment_blocks[flash_segment_id] =
+			le32_to_cpu(segment_info.size) /
+				SCARLETT2_FLASH_BLOCK_SIZE;
+	}
+
+	/* segment 0 is App_Gold and we never want to touch that, so
+	 * use 0 as the "not-found" value
+	 */
+	if (!private->flash_segment_nums[SCARLETT2_SEGMENT_ID_SETTINGS]) {
+		usb_audio_err(mixer->chip,
+			      "failed to find flash segment %s\n",
+			      SCARLETT2_SEGMENT_SETTINGS_NAME);
+		return -EINVAL;
+	}
+	if (!private->flash_segment_nums[SCARLETT2_SEGMENT_ID_FIRMWARE]) {
+		usb_audio_err(mixer->chip,
+			      "failed to find flash segment %s\n",
+			      SCARLETT2_SEGMENT_FIRMWARE_NAME);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Read configuration from the interface on start */
+static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	u16 min_firmware_version = info->config_sets[0].from_firmware_version;
+	int err, i;
+
+	if (scarlett2_has_config_item(private, SCARLETT2_CONFIG_MSD_SWITCH)) {
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_MSD_SWITCH,
+			1, &private->msd_switch);
+		if (err < 0)
+			return err;
+	}
+
+	if (private->firmware_version < min_firmware_version) {
+		usb_audio_err(mixer->chip,
+			      "Focusrite %s firmware version %d is too old; "
+			      "need %d",
+			      private->series_name,
+			      private->firmware_version,
+			      min_firmware_version);
+		return 0;
+	}
+
+	/* no other controls are created if MSD mode is on */
+	if (private->msd_switch)
+		return 0;
+
+	err = scarlett2_update_input_level(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_input_pad(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_input_air(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_input_dsp(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_compressor_values(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_filter_values(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_input_mute(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_input_phantom(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_direct_monitor(mixer);
+	if (err < 0)
+		return err;
+
+	/* the rest of the configuration is for devices with a mixer */
+	if (!scarlett2_has_mixer(private))
+		return 0;
+
+	err = scarlett2_update_monitor_mix(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_monitor_other(mixer);
+	if (err < 0)
+		return err;
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_STANDALONE_SWITCH)) {
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_STANDALONE_SWITCH,
+			1, &private->standalone_switch);
+		if (err < 0)
+			return err;
+	}
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_POWER_EXT)) {
+		err = scarlett2_update_power_status(mixer);
+		if (err < 0)
+			return err;
+	}
+
+	err = scarlett2_update_sync(mixer);
+	if (err < 0)
+		return err;
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_LINE_OUT_VOLUME)) {
+		s16 sw_vol[SCARLETT2_ANALOGUE_MAX];
+
+		/* read SW line out volume */
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_LINE_OUT_VOLUME,
+			private->num_line_out, &sw_vol);
+		if (err < 0)
+			return err;
+
+		for (i = 0; i < private->num_line_out; i++)
+			private->vol[i] = clamp(
+				sw_vol[i] + SCARLETT2_VOLUME_BIAS,
+				0, SCARLETT2_VOLUME_BIAS);
+
+		/* read SW mute */
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_MUTE_SWITCH,
+			private->num_line_out, &private->mute_switch);
+		if (err < 0)
+			return err;
+
+		for (i = 0; i < private->num_line_out; i++)
+			private->mute_switch[i] =
+				!!private->mute_switch[i];
+
+		/* read SW/HW switches */
+		if (scarlett2_has_config_item(private,
+					      SCARLETT2_CONFIG_SW_HW_SWITCH)) {
+			err = scarlett2_usb_get_config(
+				mixer, SCARLETT2_CONFIG_SW_HW_SWITCH,
+				private->num_line_out,
+				&private->vol_sw_hw_switch);
+			if (err < 0)
+				return err;
+
+			for (i = 0; i < private->num_line_out; i++)
+				private->vol_sw_hw_switch[i] =
+					!!private->vol_sw_hw_switch[i];
+		}
+	}
+
+	err = scarlett2_update_volumes(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_dim_mute(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_input_select(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_input_gain(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_autogain(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_input_safe(mixer);
+	if (err < 0)
+		return err;
+
+	if (scarlett2_has_config_item(private,
+				      SCARLETT2_CONFIG_PCM_INPUT_SWITCH)) {
+		err = scarlett2_update_pcm_input_switch(mixer);
+		if (err < 0)
+			return err;
+	}
+
+	err = scarlett2_update_bluetooth_volume(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_fp(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_spdif_mode(mixer);
+	if (err < 0)
+		return err;
+
+	err = scarlett2_update_mix(mixer);
+	if (err < 0)
+		return err;
+
+	return scarlett2_usb_get_mux(mixer);
+}
+
+static const struct scarlett2_device_entry *get_scarlett2_device_entry(
+	struct usb_mixer_interface *mixer)
+{
+	const struct scarlett2_device_entry *entry = scarlett2_devices;
+
+	/* Find entry in scarlett2_devices */
+	while (entry->usb_id && entry->usb_id != mixer->chip->usb_id)
+		entry++;
+	if (!entry->usb_id)
+		return NULL;
+
+	return entry;
+}
+
+static int snd_scarlett2_controls_create(
+	struct usb_mixer_interface *mixer,
+	const struct scarlett2_device_entry *entry)
+{
+	struct scarlett2_data *private;
+	u16 min_firmware_version;
+	int err;
+
+	/* Initialise private data */
+	err = scarlett2_init_private(mixer, entry);
+	if (err < 0)
+		return err;
+
+	private = mixer->private_data;
+	min_firmware_version =
+		private->info->config_sets[0].from_firmware_version;
+
+	/* Send proprietary USB initialisation sequence */
+	err = scarlett2_usb_init(mixer);
+	if (err < 0)
+		return err;
+
+	/* Now that the firmware version is known, pick the matching
+	 * config_set
+	 */
+	scarlett2_resolve_config_set(private);
+
+	scarlett2_count_io(private);
+
+	/* Get the upgrade & settings flash segment numbers */
+	err = scarlett2_get_flash_segment_nums(mixer);
+	if (err < 0)
+		return err;
+
+	/* Add firmware version control */
+	err = scarlett2_add_firmware_version_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Add minimum firmware version control */
+	err = scarlett2_add_min_firmware_version_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Read volume levels and controls from the interface */
+	err = scarlett2_read_configs(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the MSD control */
+	err = scarlett2_add_msd_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* If MSD mode is enabled, or if the firmware version is too
+	 * old, don't create any other controls
+	 */
+	if (private->msd_switch ||
+	    private->firmware_version < min_firmware_version)
+		return 0;
+
+	/* Create the analogue output controls */
+	err = scarlett2_add_line_out_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the analogue input controls */
+	err = scarlett2_add_line_in_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the input, output, and mixer mux input selections */
+	err = scarlett2_add_mux_enums(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the matrix mixer controls */
+	err = scarlett2_add_mixer_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the level meter controls */
+	err = scarlett2_add_meter_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the sync control */
+	err = scarlett2_add_sync_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the direct monitor control(s) */
+	err = scarlett2_add_direct_monitor_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the speaker switching control */
+	err = scarlett2_add_speaker_switch_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the talkback controls */
+	err = scarlett2_add_talkback_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the standalone control */
+	err = scarlett2_add_standalone_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the power status control */
+	err = scarlett2_add_power_status_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the Bluetooth volume control */
+	err = scarlett2_add_bluetooth_volume_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the front-panel brightness/sleep controls */
+	err = scarlett2_add_fp_ctls(mixer);
+	if (err < 0)
+		return err;
+
+	/* Create the S/PDIF mode control */
+	err = scarlett2_add_spdif_mode_ctl(mixer);
+	if (err < 0)
+		return err;
+
+	/* Set the access mode of controls disabled during
+	 * autogain/phantom power switching.
+	 */
+	if (private->info->gain_input_count) {
+		scarlett2_autogain_update_access(mixer);
+		scarlett2_phantom_update_access(mixer);
+	}
+
+	/* Start handling all notifications */
+	private->running = 2;
+
+	return 0;
+}
+
+/*** hwdep interface ***/
+
+/* Set private->hwdep_in_use; prevents access to the ALSA controls
+ * while doing a config erase/firmware upgrade.
+ */
+static void scarlett2_lock(struct scarlett2_data *private)
+{
+	guard(mutex)(&private->data_mutex);
+	private->hwdep_in_use = 1;
+}
+
+/* Call SCARLETT2_USB_GET_ERASE to get the erase progress */
+static int scarlett2_get_erase_progress(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int segment_id, segment_num, err;
+	u8 erase_resp;
+
+	struct {
+		__le32 segment_num;
+		__le32 pad;
+	} __packed erase_req;
+
+	segment_id = private->selected_flash_segment_id;
+	segment_num = private->flash_segment_nums[segment_id];
+
+	if (segment_num < SCARLETT2_SEGMENT_NUM_MIN ||
+	    segment_num > SCARLETT2_SEGMENT_NUM_MAX)
+		return -EFAULT;
+
+	/* Send the erase progress request */
+	erase_req.segment_num = cpu_to_le32(segment_num);
+	erase_req.pad = 0;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_GET_ERASE,
+			    &erase_req, sizeof(erase_req),
+			    &erase_resp, sizeof(erase_resp));
+	if (err < 0)
+		return err;
+
+	return erase_resp;
+}
+
+/* Repeatedly call scarlett2_get_erase_progress() until it returns
+ * 0xff (erase complete) or we've waited 10 seconds (it usually takes
+ * <3 seconds).
+ */
+static int scarlett2_wait_for_erase(struct usb_mixer_interface *mixer)
+{
+	int i, err;
+
+	for (i = 0; i < 100; i++) {
+		err = scarlett2_get_erase_progress(mixer);
+		if (err < 0)
+			return err;
+
+		if (err == 0xff)
+			return 0;
+
+		msleep(100);
+	}
+
+	return -ETIMEDOUT;
+}
+
+/* Reboot the device; wait for the erase to complete if one is in
+ * progress.
+ */
+static int scarlett2_reboot(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+
+	if (private->flash_write_state ==
+	      SCARLETT2_FLASH_WRITE_STATE_ERASING) {
+		int err = scarlett2_wait_for_erase(mixer);
+
+		if (err < 0)
+			return err;
+	}
+
+	return scarlett2_usb(mixer, SCARLETT2_USB_REBOOT, NULL, 0, NULL, 0);
+}
+
+/* Select a flash segment for reading/erasing/writing */
+static int scarlett2_ioctl_select_flash_segment(
+	struct usb_mixer_interface *mixer,
+	unsigned long arg)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int segment_id, segment_num;
+
+	if (get_user(segment_id, (int __user *)arg))
+		return -EFAULT;
+
+	/* Check the segment ID and segment number */
+	if (segment_id < 0 || segment_id >= SCARLETT2_SEGMENT_ID_COUNT)
+		return -EINVAL;
+
+	segment_num = private->flash_segment_nums[segment_id];
+	if (segment_num < SCARLETT2_SEGMENT_NUM_MIN ||
+	    segment_num > SCARLETT2_SEGMENT_NUM_MAX) {
+		usb_audio_err(mixer->chip,
+			      "%s: invalid segment number %d\n",
+			      __func__, segment_id);
+		return -EFAULT;
+	}
+
+	/* If erasing, wait for it to complete */
+	if (private->flash_write_state == SCARLETT2_FLASH_WRITE_STATE_ERASING) {
+		int err = scarlett2_wait_for_erase(mixer);
+
+		if (err < 0)
+			return err;
+	}
+
+	/* Save the selected segment ID and set the state to SELECTED */
+	private->selected_flash_segment_id = segment_id;
+	private->flash_write_state = SCARLETT2_FLASH_WRITE_STATE_SELECTED;
+
+	return 0;
+}
+
+/* Erase the previously-selected flash segment */
+static int scarlett2_ioctl_erase_flash_segment(
+	struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int segment_id, segment_num, err;
+
+	struct {
+		__le32 segment_num;
+		__le32 pad;
+	} __packed erase_req;
+
+	if (private->flash_write_state != SCARLETT2_FLASH_WRITE_STATE_SELECTED)
+		return -EINVAL;
+
+	segment_id = private->selected_flash_segment_id;
+	segment_num = private->flash_segment_nums[segment_id];
+
+	if (segment_num < SCARLETT2_SEGMENT_NUM_MIN ||
+	    segment_num > SCARLETT2_SEGMENT_NUM_MAX)
+		return -EFAULT;
+
+	/* Prevent access to ALSA controls that access the device from
+	 * here on
+	 */
+	scarlett2_lock(private);
+
+	/* Send the erase request */
+	erase_req.segment_num = cpu_to_le32(segment_num);
+	erase_req.pad = 0;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_ERASE_SEGMENT,
+			    &erase_req, sizeof(erase_req),
+			    NULL, 0);
+	if (err < 0)
+		return err;
+
+	/* On success, change the state from SELECTED to ERASING */
+	private->flash_write_state = SCARLETT2_FLASH_WRITE_STATE_ERASING;
+
+	return 0;
+}
+
+/* Get the erase progress from the device */
+static int scarlett2_ioctl_get_erase_progress(
+	struct usb_mixer_interface *mixer,
+	unsigned long arg)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	struct scarlett2_flash_segment_erase_progress progress;
+	int segment_id, segment_num, err;
+	u8 erase_resp;
+
+	struct {
+		__le32 segment_num;
+		__le32 pad;
+	} __packed erase_req;
+
+	/* Check that we're erasing */
+	if (private->flash_write_state != SCARLETT2_FLASH_WRITE_STATE_ERASING)
+		return -EINVAL;
+
+	segment_id = private->selected_flash_segment_id;
+	segment_num = private->flash_segment_nums[segment_id];
+
+	if (segment_num < SCARLETT2_SEGMENT_NUM_MIN ||
+	    segment_num > SCARLETT2_SEGMENT_NUM_MAX)
+		return -EFAULT;
+
+	/* Send the erase progress request */
+	erase_req.segment_num = cpu_to_le32(segment_num);
+	erase_req.pad = 0;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_GET_ERASE,
+			    &erase_req, sizeof(erase_req),
+			    &erase_resp, sizeof(erase_resp));
+	if (err < 0)
+		return err;
+
+	progress.progress = erase_resp;
+	progress.num_blocks = private->flash_segment_blocks[segment_id];
+
+	if (copy_to_user((void __user *)arg, &progress, sizeof(progress)))
+		return -EFAULT;
+
+	/* If the erase is complete, change the state from ERASING to
+	 * WRITE.
+	 */
+	if (progress.progress == 0xff)
+		private->flash_write_state = SCARLETT2_FLASH_WRITE_STATE_WRITE;
+
+	return 0;
+}
+
+static int scarlett2_hwdep_open(struct snd_hwdep *hw, struct file *file)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct scarlett2_data *private = mixer->private_data;
+
+	/* If erasing, wait for it to complete */
+	if (private->flash_write_state ==
+	      SCARLETT2_FLASH_WRITE_STATE_ERASING) {
+		int err = scarlett2_wait_for_erase(mixer);
+
+		if (err < 0)
+			return err;
+	}
+
+	/* Set the state to IDLE */
+	private->flash_write_state = SCARLETT2_FLASH_WRITE_STATE_IDLE;
+
+	return 0;
+}
+
+static int scarlett2_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
+				 unsigned int cmd, unsigned long arg)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+
+	switch (cmd) {
+
+	case SCARLETT2_IOCTL_PVERSION:
+		return put_user(SCARLETT2_HWDEP_VERSION,
+				(int __user *)arg) ? -EFAULT : 0;
+
+	case SCARLETT2_IOCTL_REBOOT:
+		return scarlett2_reboot(mixer);
+
+	case SCARLETT2_IOCTL_SELECT_FLASH_SEGMENT:
+		return scarlett2_ioctl_select_flash_segment(mixer, arg);
+
+	case SCARLETT2_IOCTL_ERASE_FLASH_SEGMENT:
+		return scarlett2_ioctl_erase_flash_segment(mixer);
+
+	case SCARLETT2_IOCTL_GET_ERASE_PROGRESS:
+		return scarlett2_ioctl_get_erase_progress(mixer, arg);
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+static long scarlett2_hwdep_read(struct snd_hwdep *hw,
+				 char __user *buf,
+				 long count, loff_t *offset)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct scarlett2_data *private = mixer->private_data;
+	int segment_id, segment_num, err;
+	int flash_size;
+
+	/* SCARLETT2_USB_READ_SEGMENT request data */
+	struct {
+		__le32 segment_num;
+		__le32 offset;
+		__le32 len;
+	} __packed req;
+
+	/* Flash segment must first be selected */
+	if (private->flash_write_state != SCARLETT2_FLASH_WRITE_STATE_SELECTED)
+		return -EINVAL;
+
+	/* Get the selected flash segment number */
+	segment_id = private->selected_flash_segment_id;
+	if (segment_id < 0 || segment_id >= SCARLETT2_SEGMENT_ID_COUNT)
+		return -EINVAL;
+
+	segment_num = private->flash_segment_nums[segment_id];
+	if (segment_num < 0 ||
+	    segment_num > SCARLETT2_SEGMENT_NUM_MAX)
+		return -EFAULT;
+
+	/* Validate the offset and count */
+	if (count < 0 || *offset < 0)
+		return -EINVAL;
+
+	/* Reached EOF? */
+	flash_size = private->flash_segment_blocks[segment_id] *
+		     SCARLETT2_FLASH_BLOCK_SIZE;
+	if (!count || *offset >= flash_size)
+		return 0;
+
+	/* Limit the numbers of bytes read to SCARLETT2_FLASH_RW_MAX */
+	if (count > SCARLETT2_FLASH_RW_MAX)
+		count = SCARLETT2_FLASH_RW_MAX;
+
+	/* Limit read to EOF */
+	if (*offset + count >= flash_size)
+		count = flash_size - *offset;
+
+	/* Create and send the request */
+	req.segment_num = cpu_to_le32(segment_num);
+	req.offset = cpu_to_le32(*offset);
+	req.len = cpu_to_le32(count);
+
+	u8 *resp __free(kfree) =
+		kzalloc(count, GFP_KERNEL);
+	if (!resp)
+		return -ENOMEM;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_READ_SEGMENT,
+			    &req, sizeof(req), resp, count);
+	if (err < 0)
+		return err;
+
+	/* Copy the response to userspace */
+	if (copy_to_user(buf, resp, count))
+		return -EFAULT;
+
+	*offset += count;
+	return count;
+}
+
+static long scarlett2_hwdep_write(struct snd_hwdep *hw,
+				  const char __user *buf,
+				  long count, loff_t *offset)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct scarlett2_data *private = mixer->private_data;
+	int segment_id, segment_num, err, len;
+	int flash_size;
+
+	/* SCARLETT2_USB_WRITE_SEGMENT request data */
+	struct {
+		__le32 segment_num;
+		__le32 offset;
+		__le32 pad;
+		u8 data[];
+	} __packed *req __free(kfree) = NULL;
+
+	/* Calculate the maximum permitted in data[] */
+	const size_t max_data_size = SCARLETT2_FLASH_RW_MAX -
+				     offsetof(typeof(*req), data);
+
+	/* If erasing, wait for it to complete */
+	if (private->flash_write_state ==
+	      SCARLETT2_FLASH_WRITE_STATE_ERASING) {
+		err = scarlett2_wait_for_erase(mixer);
+		if (err < 0)
+			return err;
+		private->flash_write_state = SCARLETT2_FLASH_WRITE_STATE_WRITE;
+
+	/* Check that an erase has been done & completed */
+	} else if (private->flash_write_state !=
+		     SCARLETT2_FLASH_WRITE_STATE_WRITE) {
+		return -EINVAL;
+	}
+
+	/* Check that we're writing to the upgrade firmware */
+	segment_id = private->selected_flash_segment_id;
+	if (segment_id != SCARLETT2_SEGMENT_ID_FIRMWARE)
+		return -EINVAL;
+
+	segment_num = private->flash_segment_nums[segment_id];
+	if (segment_num < SCARLETT2_SEGMENT_NUM_MIN ||
+	    segment_num > SCARLETT2_SEGMENT_NUM_MAX)
+		return -EFAULT;
+
+	/* Validate the offset and count */
+	flash_size = private->flash_segment_blocks[segment_id] *
+		     SCARLETT2_FLASH_BLOCK_SIZE;
+
+	if (count < 0 || *offset < 0)
+		return -EINVAL;
+
+	if (!count)
+		return 0;
+
+	if (*offset >= flash_size || count > flash_size - *offset)
+		return -ENOSPC;
+
+	/* Limit the *req size to SCARLETT2_FLASH_RW_MAX */
+	if (count > max_data_size)
+		count = max_data_size;
+
+	/* Create and send the request */
+	len = struct_size(req, data, count);
+	req = kzalloc_flex(*req, data, count);
+	if (!req)
+		return -ENOMEM;
+
+	req->segment_num = cpu_to_le32(segment_num);
+	req->offset = cpu_to_le32(*offset);
+	req->pad = 0;
+
+	if (copy_from_user(req->data, buf, count))
+		return -EFAULT;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_WRITE_SEGMENT,
+			    req, len, NULL, 0);
+	if (err < 0)
+		return err;
+
+	*offset += count;
+	return count;
+}
+
+static int scarlett2_hwdep_release(struct snd_hwdep *hw, struct file *file)
+{
+	struct usb_mixer_interface *mixer = hw->private_data;
+	struct scarlett2_data *private = mixer->private_data;
+
+	/* Return from the SELECTED or WRITE state to IDLE.
+	 * The ERASING state is left as-is, and checked on next open.
+	 */
+	if (private &&
+	    private->hwdep_in_use &&
+	    private->flash_write_state != SCARLETT2_FLASH_WRITE_STATE_ERASING)
+		private->flash_write_state = SCARLETT2_FLASH_WRITE_STATE_IDLE;
+
+	return 0;
+}
+
+static int scarlett2_hwdep_init(struct usb_mixer_interface *mixer)
+{
+	struct snd_hwdep *hw;
+	int err;
+
+	err = snd_hwdep_new(mixer->chip->card, "Focusrite Control", 0, &hw);
+	if (err < 0)
+		return err;
+
+	hw->private_data = mixer;
+	hw->exclusive = 1;
+	hw->ops.open = scarlett2_hwdep_open;
+	hw->ops.ioctl = scarlett2_hwdep_ioctl;
+	hw->ops.read = scarlett2_hwdep_read;
+	hw->ops.write = scarlett2_hwdep_write;
+	hw->ops.release = scarlett2_hwdep_release;
+
+	return 0;
+}
+
+/*** device-map file ***/
+
+static ssize_t scarlett2_devmap_read(
+	struct snd_info_entry *entry,
+	void                  *file_private_data,
+	struct file           *file,
+	char __user           *buf,
+	size_t                 count,
+	loff_t                 pos)
+{
+	struct usb_mixer_interface *mixer = entry->private_data;
+	const size_t  block_size = SCARLETT2_DEVMAP_BLOCK_SIZE;
+	size_t        copied = 0;
+
+	if (pos >= entry->size)
+		return 0;
+
+	if (pos + count > entry->size)
+		count = entry->size - pos;
+
+	u8 *resp_buf __free(kfree) =
+		kmalloc(block_size, GFP_KERNEL);
+	if (!resp_buf)
+		return -ENOMEM;
+
+	while (count > 0) {
+		/* SCARLETT2_USB_GET_DEVMAP reads only on block boundaries,
+		 * so we need to read a whole block and copy the requested
+		 * chunk to userspace.
+		 */
+
+		__le32 req;
+		int    err;
+
+		/* offset within the block that we're reading */
+		size_t offset = pos % block_size;
+
+		/* read_size is block_size except for the last block */
+		size_t block_start = pos - offset;
+		size_t read_size = min_t(size_t,
+					 block_size,
+					 entry->size - block_start);
+
+		/* size of the chunk to copy to userspace */
+		size_t copy_size = min_t(size_t, count, read_size - offset);
+
+		/* request the block */
+		req = cpu_to_le32(pos / block_size);
+		err = scarlett2_usb(mixer, SCARLETT2_USB_GET_DEVMAP,
+				    &req, sizeof(req), resp_buf, read_size);
+		if (err < 0)
+			return copied ? copied : err;
+
+		if (copy_to_user(buf, resp_buf + offset, copy_size))
+			return -EFAULT;
+
+		buf += copy_size;
+		pos += copy_size;
+		copied += copy_size;
+		count -= copy_size;
+	}
+
+	return copied;
+}
+
+static const struct snd_info_entry_ops scarlett2_devmap_ops = {
+	.read = scarlett2_devmap_read,
+};
+
+static int scarlett2_devmap_init(struct usb_mixer_interface *mixer)
+{
+	struct snd_card *card = mixer->chip->card;
+	struct scarlett2_data *private = mixer->private_data;
+	const struct scarlett2_device_info *info = private->info;
+	__le16 config_len_buf[2];
+	int config_len;
+	struct snd_info_entry *entry;
+	int err;
+
+	/* If the device doesn't support the DEVMAP commands, don't
+	 * create the /proc/asound/cardX/scarlett.json.zlib entry
+	 */
+	if (!info->has_devmap)
+		return 0;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_INFO_DEVMAP,
+			    NULL, 0, &config_len_buf, sizeof(config_len_buf));
+	if (err < 0)
+		return err;
+
+	config_len = le16_to_cpu(config_len_buf[1]);
+
+	err = snd_card_proc_new(card, SCARLETT2_DEVMAP_FILENAME, &entry);
+	if (err < 0)
+		return err;
+
+	entry->content = SNDRV_INFO_CONTENT_DATA;
+	entry->private_data = mixer;
+	entry->c.ops = &scarlett2_devmap_ops;
+	entry->size = config_len;
+	entry->mode = S_IFREG | 0444;
+
+	return 0;
+}
+
+int snd_scarlett2_init(struct usb_mixer_interface *mixer)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	const struct scarlett2_device_entry *entry;
+	int err;
+
+	/* only use UAC_VERSION_2 */
+	if (!mixer->protocol)
+		return 0;
+
+	/* check if the user wants to use the FCP driver instead */
+	if (chip->setup & SCARLETT2_USE_FCP_DRIVER)
+		return snd_fcp_init(mixer);
+
+	/* find entry in scarlett2_devices */
+	entry = get_scarlett2_device_entry(mixer);
+	if (!entry) {
+		usb_audio_err(mixer->chip,
+			      "%s: missing device entry for %04x:%04x\n",
+			      __func__,
+			      USB_ID_VENDOR(chip->usb_id),
+			      USB_ID_PRODUCT(chip->usb_id));
+		return 0;
+	}
+
+	if (chip->setup & SCARLETT2_DISABLE) {
+		usb_audio_info(chip,
+			"Focusrite %s Mixer Driver disabled "
+			"by modprobe options (snd_usb_audio "
+			"vid=0x%04x pid=0x%04x device_setup=%d)\n",
+			entry->series_name,
+			USB_ID_VENDOR(chip->usb_id),
+			USB_ID_PRODUCT(chip->usb_id),
+			SCARLETT2_DISABLE);
+		return 0;
+	}
+
+	usb_audio_info(chip,
+		"Focusrite %s Mixer Driver enabled (pid=0x%04x); "
+		"report any issues to "
+		"https://github.com/geoffreybennett/scarlett-gen2/issues",
+		entry->series_name,
+		USB_ID_PRODUCT(chip->usb_id));
+
+	err = snd_scarlett2_controls_create(mixer, entry);
+	if (err < 0) {
+		usb_audio_err(mixer->chip,
+			      "Error initialising %s Mixer Driver: %d",
+			      entry->series_name,
+			      err);
+		return err;
+	}
+
+	err = scarlett2_hwdep_init(mixer);
+	if (err < 0) {
+		usb_audio_err(mixer->chip,
+			      "Error creating %s hwdep device: %d",
+			      entry->series_name,
+			      err);
+		return err;
+	}
+
+	err = scarlett2_devmap_init(mixer);
+	if (err < 0)
+		usb_audio_err(mixer->chip,
+			      "Error creating %s devmap entry: %d",
+			      entry->series_name,
+			      err);
+
+	return err;
+}
diff --git a/sound/usb/mixer_scarlett2.h b/sound/usb/mixer_scarlett2.h
new file mode 100644
index 000000000..d209362cf
--- /dev/null
+++ b/sound/usb/mixer_scarlett2.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USB_MIXER_SCARLETT2_H
+#define __USB_MIXER_SCARLETT2_H
+
+int snd_scarlett2_init(struct usb_mixer_interface *mixer);
+
+#endif /* __USB_MIXER_SCARLETT2_H */
diff --git a/sound/usb/mixer_us16x08.c b/sound/usb/mixer_us16x08.c
new file mode 100644
index 000000000..14fb1ad76
--- /dev/null
+++ b/sound/usb/mixer_us16x08.c
@@ -0,0 +1,1453 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Tascam US-16x08 ALSA driver
+ *
+ *   Copyright (c) 2016 by Detlef Urban (onkel@paraair.de)
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio-v2.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+
+#include "usbaudio.h"
+#include "mixer.h"
+#include "helper.h"
+
+#include "mixer_us16x08.h"
+
+/* USB control message templates */
+static const char route_msg[] = {
+	0x61,
+	0x02,
+	0x03, /* input from master (0x02) or input from computer bus (0x03) */
+	0x62,
+	0x02,
+	0x01, /* input index (0x01/0x02 eq. left/right) or bus (0x01-0x08) */
+	0x41,
+	0x01,
+	0x61,
+	0x02,
+	0x01,
+	0x62,
+	0x02,
+	0x01, /* output index (0x01-0x08) */
+	0x42,
+	0x01,
+	0x43,
+	0x01,
+	0x00,
+	0x00
+};
+
+static const char mix_init_msg1[] = {
+	0x71, 0x01, 0x00, 0x00
+};
+
+static const char mix_init_msg2[] = {
+	0x62, 0x02, 0x00, 0x61, 0x02, 0x04, 0xb1, 0x01, 0x00, 0x00
+};
+
+static const char mix_msg_in[] = {
+	/* default message head, equal to all mixers */
+	0x61, 0x02, 0x04, 0x62, 0x02, 0x01,
+	0x81, /* 0x06: Controller ID */
+	0x02, /* 0x07:  */
+	0x00, /* 0x08: Value of common mixer */
+	0x00,
+	0x00
+};
+
+static const char mix_msg_out[] = {
+	/* default message head, equal to all mixers */
+	0x61, 0x02, 0x02, 0x62, 0x02, 0x01,
+	0x81, /* 0x06: Controller ID */
+	0x02, /*                    0x07:  */
+	0x00, /*                    0x08: Value of common mixer */
+	0x00,
+	0x00
+};
+
+static const char bypass_msg_out[] = {
+	0x45,
+	0x02,
+	0x01, /* on/off flag */
+	0x00,
+	0x00
+};
+
+static const char bus_msg_out[] = {
+	0x44,
+	0x02,
+	0x01, /* on/off flag */
+	0x00,
+	0x00
+};
+
+static const char comp_msg[] = {
+	/* default message head, equal to all mixers */
+	0x61, 0x02, 0x04, 0x62, 0x02, 0x01,
+	0x91,
+	0x02,
+	0xf0, /* 0x08: Threshold db (8) (e0 ... 00) (+-0dB -- -32dB) x-32 */
+	0x92,
+	0x02,
+	0x0a, /* 0x0b: Ratio (0a,0b,0d,0f,11,14,19,1e,23,28,32,3c,50,a0,ff)  */
+	0x93,
+	0x02,
+	0x02, /* 0x0e: Attack (0x02 ... 0xc0) (2ms ... 200ms) */
+	0x94,
+	0x02,
+	0x01, /* 0x11: Release (0x01 ... 0x64) (10ms ... 1000ms) x*10  */
+	0x95,
+	0x02,
+	0x03, /* 0x14: gain (0 ... 20) (0dB .. 20dB) */
+	0x96,
+	0x02,
+	0x01,
+	0x97,
+	0x02,
+	0x01, /* 0x1a: main Comp switch (0 ... 1) (off ... on)) */
+	0x00,
+	0x00
+};
+
+static const char eqs_msq[] = {
+	/* default message head, equal to all mixers */
+	0x61, 0x02, 0x04, 0x62, 0x02, 0x01,
+	0x51, /*                0x06: Controller ID  */
+	0x02,
+	0x04, /* 0x08: EQ set num (0x01..0x04) (LOW, LOWMID, HIGHMID, HIGH)) */
+	0x52,
+	0x02,
+	0x0c, /* 0x0b: value dB (0 ... 12) (-12db .. +12db)  x-6 */
+	0x53,
+	0x02,
+	0x0f, /* 0x0e: value freq (32-47) (1.7kHz..18kHz) */
+	0x54,
+	0x02,
+	0x02, /* 0x11: band width (0-6) (Q16-Q0.25)  2^x/4 (EQ xxMID only) */
+	0x55,
+	0x02,
+	0x01, /* 0x14: main EQ switch (0 ... 1) (off ... on)) */
+	0x00,
+	0x00
+};
+
+/* compressor ratio map */
+static const char ratio_map[] = {
+	0x0a, 0x0b, 0x0d, 0x0f, 0x11, 0x14, 0x19, 0x1e,
+	0x23, 0x28, 0x32, 0x3c, 0x50, 0xa0, 0xff
+};
+
+/* route enumeration names */
+static const char *const route_names[] = {
+	"Master Left", "Master Right", "Output 1", "Output 2", "Output 3",
+	"Output 4", "Output 5", "Output 6", "Output 7", "Output 8",
+};
+
+static int snd_us16x08_recv_urb(struct snd_usb_audio *chip,
+	unsigned char *buf, int size)
+{
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	guard(mutex)(&chip->mutex);
+	snd_usb_ctl_msg(chip->dev,
+		usb_rcvctrlpipe(chip->dev, 0),
+		SND_US16X08_URB_METER_REQUEST,
+		SND_US16X08_URB_METER_REQUESTTYPE, 0, 0, buf, size);
+	return 0;
+}
+
+/* wrapper function to send prepared URB buffer to usb device. Return an error
+ * code if something went wrong
+ */
+static int snd_us16x08_send_urb(struct snd_usb_audio *chip, char *buf, int size)
+{
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return -EIO;
+
+	return snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
+			SND_US16X08_URB_REQUEST, SND_US16X08_URB_REQUESTTYPE,
+			0, 0, buf, size);
+}
+
+static int snd_us16x08_route_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	return snd_ctl_enum_info(uinfo, 1, 10, route_names);
+}
+
+static int snd_us16x08_route_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	int index = ucontrol->id.index;
+
+	/* route has no bias */
+	ucontrol->value.enumerated.item[0] = elem->cache_val[index];
+
+	return 0;
+}
+
+static int snd_us16x08_route_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	int index = ucontrol->id.index;
+	char buf[sizeof(route_msg)];
+	int val, val_org, err;
+
+	/*  get the new value (no bias for routes) */
+	val = ucontrol->value.enumerated.item[0];
+
+	/* sanity check */
+	if (val < 0 || val > 9)
+		return -EINVAL;
+
+	/* prepare the message buffer from template */
+	memcpy(buf, route_msg, sizeof(route_msg));
+
+	if (val < 2) {
+		/* input comes from a master channel */
+		val_org = val;
+		buf[2] = 0x02;
+	} else {
+		/* input comes from a computer channel */
+		buf[2] = 0x03;
+		val_org = val - 2;
+	}
+
+	/* place new route selection in URB message */
+	buf[5] = (unsigned char) (val_org & 0x0f) + 1;
+	/* place route selector in URB message */
+	buf[13] = index + 1;
+
+	err = snd_us16x08_send_urb(chip, buf, sizeof(route_msg));
+
+	if (err < 0) {
+		usb_audio_dbg(chip, "Failed to set routing, err:%d\n", err);
+		return err;
+	}
+
+	elem->cached |= 1 << index;
+	elem->cache_val[index] = val;
+	return 1;
+}
+
+static int snd_us16x08_master_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->count = 1;
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->value.integer.max = SND_US16X08_KCMAX(kcontrol);
+	uinfo->value.integer.min = SND_US16X08_KCMIN(kcontrol);
+	uinfo->value.integer.step = SND_US16X08_KCSTEP(kcontrol);
+	return 0;
+}
+
+static int snd_us16x08_master_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	int index = ucontrol->id.index;
+
+	ucontrol->value.integer.value[0] = elem->cache_val[index];
+
+	return 0;
+}
+
+static int snd_us16x08_master_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	char buf[sizeof(mix_msg_out)];
+	int val, err;
+	int index = ucontrol->id.index;
+
+	/* new control value incl. bias*/
+	val = ucontrol->value.integer.value[0];
+
+	/* sanity check */
+	if (val < SND_US16X08_KCMIN(kcontrol)
+		|| val > SND_US16X08_KCMAX(kcontrol))
+		return -EINVAL;
+
+	/* prepare the message buffer from template */
+	memcpy(buf, mix_msg_out, sizeof(mix_msg_out));
+
+	buf[8] = val - SND_US16X08_KCBIAS(kcontrol);
+	buf[6] = elem->head.id;
+
+	/* place channel selector in URB message */
+	buf[5] = index + 1;
+	err = snd_us16x08_send_urb(chip, buf, sizeof(mix_msg_out));
+
+	if (err < 0) {
+		usb_audio_dbg(chip, "Failed to set master, err:%d\n", err);
+		return err;
+	}
+
+	elem->cached |= 1 << index;
+	elem->cache_val[index] = val;
+	return 1;
+}
+
+static int snd_us16x08_bus_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	char buf[sizeof(mix_msg_out)];
+	int val, err = 0;
+
+	val = ucontrol->value.integer.value[0];
+
+	/* prepare the message buffer from template */
+	switch (elem->head.id) {
+	case SND_US16X08_ID_BYPASS:
+		memcpy(buf, bypass_msg_out, sizeof(bypass_msg_out));
+		buf[2] = val;
+		err = snd_us16x08_send_urb(chip, buf, sizeof(bypass_msg_out));
+		break;
+	case SND_US16X08_ID_BUSS_OUT:
+		memcpy(buf, bus_msg_out, sizeof(bus_msg_out));
+		buf[2] = val;
+		err = snd_us16x08_send_urb(chip, buf, sizeof(bus_msg_out));
+		break;
+	case SND_US16X08_ID_MUTE:
+		memcpy(buf, mix_msg_out, sizeof(mix_msg_out));
+		buf[8] = val;
+		buf[6] = elem->head.id;
+		buf[5] = 1;
+		err = snd_us16x08_send_urb(chip, buf, sizeof(mix_msg_out));
+		break;
+	}
+
+	if (err < 0) {
+		usb_audio_dbg(chip, "Failed to set bus parameter, err:%d\n", err);
+		return err;
+	}
+
+	elem->cached |= 1;
+	elem->cache_val[0] = val;
+	return 1;
+}
+
+static int snd_us16x08_bus_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+
+	switch (elem->head.id) {
+	case SND_US16X08_ID_BUSS_OUT:
+		ucontrol->value.integer.value[0] = elem->cache_val[0];
+		break;
+	case SND_US16X08_ID_BYPASS:
+		ucontrol->value.integer.value[0] = elem->cache_val[0];
+		break;
+	case SND_US16X08_ID_MUTE:
+		ucontrol->value.integer.value[0] = elem->cache_val[0];
+		break;
+	}
+
+	return 0;
+}
+
+/* gets a current mixer value from common store */
+static int snd_us16x08_channel_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	int index = ucontrol->id.index;
+
+	ucontrol->value.integer.value[0] = elem->cache_val[index];
+
+	return 0;
+}
+
+static int snd_us16x08_channel_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	char buf[sizeof(mix_msg_in)];
+	int val, err;
+	int index = ucontrol->id.index;
+
+	val = ucontrol->value.integer.value[0];
+
+	/* sanity check */
+	if (val < SND_US16X08_KCMIN(kcontrol)
+		|| val > SND_US16X08_KCMAX(kcontrol))
+		return -EINVAL;
+
+	/* prepare URB message from template */
+	memcpy(buf, mix_msg_in, sizeof(mix_msg_in));
+
+	/* add the bias to the new value */
+	buf[8] = val - SND_US16X08_KCBIAS(kcontrol);
+	buf[6] = elem->head.id;
+	buf[5] = index + 1;
+
+	err = snd_us16x08_send_urb(chip, buf, sizeof(mix_msg_in));
+
+	if (err < 0) {
+		usb_audio_dbg(chip, "Failed to set channel, err:%d\n", err);
+		return err;
+	}
+
+	elem->cached |= 1 << index;
+	elem->cache_val[index] = val;
+	return 1;
+}
+
+static int snd_us16x08_mix_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->count = 1;
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->value.integer.max = SND_US16X08_KCMAX(kcontrol);
+	uinfo->value.integer.min = SND_US16X08_KCMIN(kcontrol);
+	uinfo->value.integer.step = SND_US16X08_KCSTEP(kcontrol);
+	return 0;
+}
+
+static int snd_us16x08_comp_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_us16x08_comp_store *store = elem->private_data;
+	int index = ucontrol->id.index;
+	int val_idx = COMP_STORE_IDX(elem->head.id);
+
+	ucontrol->value.integer.value[0] = store->val[val_idx][index];
+
+	return 0;
+}
+
+static int snd_us16x08_comp_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	struct snd_us16x08_comp_store *store = elem->private_data;
+	int index = ucontrol->id.index;
+	char buf[sizeof(comp_msg)];
+	int val_idx, val;
+	int threshold, ratio, attack, release, gain, switch_on;
+	int err;
+
+	val = ucontrol->value.integer.value[0];
+
+	/* sanity check */
+	if (val < SND_US16X08_KCMIN(kcontrol)
+		|| val > SND_US16X08_KCMAX(kcontrol))
+		return -EINVAL;
+
+	/* new control value incl. bias*/
+	val_idx = elem->head.id - SND_US16X08_ID_COMP_BASE;
+
+	threshold = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_THRESHOLD)]
+		[index];
+	ratio = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_RATIO)][index];
+	attack = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_ATTACK)][index];
+	release = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_RELEASE)]
+		[index];
+	gain = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_GAIN)][index];
+	switch_on = store->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_SWITCH)]
+		[index];
+
+	switch (val_idx) {
+	case COMP_STORE_IDX(SND_US16X08_ID_COMP_THRESHOLD):
+		threshold = val;
+		break;
+	case COMP_STORE_IDX(SND_US16X08_ID_COMP_RATIO):
+		ratio = val;
+		break;
+	case COMP_STORE_IDX(SND_US16X08_ID_COMP_ATTACK):
+		attack = val;
+		break;
+	case COMP_STORE_IDX(SND_US16X08_ID_COMP_RELEASE):
+		release = val;
+		break;
+	case COMP_STORE_IDX(SND_US16X08_ID_COMP_GAIN):
+		gain = val;
+		break;
+	case COMP_STORE_IDX(SND_US16X08_ID_COMP_SWITCH):
+		switch_on = val;
+		break;
+	}
+
+	/* prepare compressor URB message from template  */
+	memcpy(buf, comp_msg, sizeof(comp_msg));
+
+	/* place comp values in message buffer watch bias! */
+	buf[8] = threshold - SND_US16X08_COMP_THRESHOLD_BIAS;
+	buf[11] = ratio_map[ratio];
+	buf[14] = attack + SND_US16X08_COMP_ATTACK_BIAS;
+	buf[17] = release + SND_US16X08_COMP_RELEASE_BIAS;
+	buf[20] = gain;
+	buf[26] = switch_on;
+
+	/* place channel selector in message buffer */
+	buf[5] = index + 1;
+
+	err = snd_us16x08_send_urb(chip, buf, sizeof(comp_msg));
+
+	if (err < 0) {
+		usb_audio_dbg(chip, "Failed to set compressor, err:%d\n", err);
+		return err;
+	}
+
+	store->val[val_idx][index] = val;
+	elem->cached |= 1 << index;
+	elem->cache_val[index] = val;
+	return 1;
+}
+
+static int snd_us16x08_eqswitch_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	int val;
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_us16x08_eq_store *store = elem->private_data;
+	int index = ucontrol->id.index;
+
+	/* get low switch from cache is enough, cause all bands are together */
+	val = store->val[EQ_STORE_BAND_IDX(elem->head.id)]
+		[EQ_STORE_PARAM_IDX(elem->head.id)][index];
+	ucontrol->value.integer.value[0] = val;
+
+	return 0;
+}
+
+static int snd_us16x08_eqswitch_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	struct snd_us16x08_eq_store *store = elem->private_data;
+	int index = ucontrol->id.index;
+	char buf[sizeof(eqs_msq)];
+	int val, err = 0;
+	int b_idx;
+
+	/* new control value incl. bias*/
+	val = ucontrol->value.integer.value[0] + SND_US16X08_KCBIAS(kcontrol);
+
+	/* prepare URB message from EQ template */
+	memcpy(buf, eqs_msq, sizeof(eqs_msq));
+
+	/* place channel index in URB message */
+	buf[5] = index + 1;
+	for (b_idx = 0; b_idx < SND_US16X08_ID_EQ_BAND_COUNT; b_idx++) {
+		/* all four EQ bands have to be enabled/disabled in once */
+		buf[20] = val;
+		buf[17] = store->val[b_idx][2][index];
+		buf[14] = store->val[b_idx][1][index];
+		buf[11] = store->val[b_idx][0][index];
+		buf[8] = b_idx + 1;
+		err = snd_us16x08_send_urb(chip, buf, sizeof(eqs_msq));
+		if (err < 0)
+			break;
+		store->val[b_idx][3][index] = val;
+		msleep(15);
+	}
+
+	if (err < 0) {
+		usb_audio_dbg(chip, "Failed to set eq switch, err:%d\n", err);
+		return err;
+	}
+
+	elem->cached |= 1 << index;
+	elem->cache_val[index] = val;
+	return 1;
+}
+
+static int snd_us16x08_eq_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	int val;
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_us16x08_eq_store *store = elem->private_data;
+	int index = ucontrol->id.index;
+	int b_idx = EQ_STORE_BAND_IDX(elem->head.id) - 1;
+	int p_idx = EQ_STORE_PARAM_IDX(elem->head.id);
+
+	val = store->val[b_idx][p_idx][index];
+
+	ucontrol->value.integer.value[0] = val;
+
+	return 0;
+}
+
+static int snd_us16x08_eq_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	struct snd_us16x08_eq_store *store = elem->private_data;
+	int index = ucontrol->id.index;
+	char buf[sizeof(eqs_msq)];
+	int val, err;
+	int b_idx = EQ_STORE_BAND_IDX(elem->head.id) - 1;
+	int p_idx = EQ_STORE_PARAM_IDX(elem->head.id);
+
+	val = ucontrol->value.integer.value[0];
+
+	/* sanity check */
+	if (val < SND_US16X08_KCMIN(kcontrol)
+		|| val > SND_US16X08_KCMAX(kcontrol))
+		return -EINVAL;
+
+	/* copy URB buffer from EQ template */
+	memcpy(buf, eqs_msq, sizeof(eqs_msq));
+
+	buf[20] = p_idx == 3 ? val : store->val[b_idx][3][index];
+	buf[17] = p_idx == 2 ? val : store->val[b_idx][2][index];
+	buf[14] = p_idx == 1 ? val : store->val[b_idx][1][index];
+	buf[11] = p_idx == 0 ? val : store->val[b_idx][0][index];
+
+	/* place channel index in URB buffer */
+	buf[5] = index + 1;
+
+	/* place EQ band in URB buffer */
+	buf[8] = b_idx + 1;
+
+	err = snd_us16x08_send_urb(chip, buf, sizeof(eqs_msq));
+
+	if (err < 0) {
+		usb_audio_dbg(chip, "Failed to set eq param, err:%d\n", err);
+		return err;
+	}
+
+	store->val[b_idx][p_idx][index] = val;
+	/* store new value in EQ band cache */
+	elem->cached |= 1 << index;
+	elem->cache_val[index] = val;
+	return 1;
+}
+
+static int snd_us16x08_meter_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->count = 34;
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->value.integer.max = 0x7FFF;
+	uinfo->value.integer.min = 0;
+
+	return 0;
+}
+
+/* calculate compressor index for reduction level request */
+static int snd_get_meter_comp_index(struct snd_us16x08_meter_store *store)
+{
+	int ret;
+
+	/* any channel active */
+	if (store->comp_active_index) {
+		/* check for stereo link */
+		if (store->comp_active_index & 0x20) {
+			/* reset comp_index to left channel*/
+			if (store->comp_index -
+				store->comp_active_index > 1)
+				store->comp_index =
+				store->comp_active_index;
+
+			ret = store->comp_index++ & 0x1F;
+		} else {
+			/* no stereo link */
+			ret = store->comp_active_index;
+		}
+	} else {
+		/* skip channels with no compressor active */
+		while (store->comp_index <= SND_US16X08_MAX_CHANNELS
+			&& !store->comp_store->val[
+			COMP_STORE_IDX(SND_US16X08_ID_COMP_SWITCH)]
+			[store->comp_index - 1]) {
+			store->comp_index++;
+		}
+		ret = store->comp_index++;
+		if (store->comp_index > SND_US16X08_MAX_CHANNELS)
+			store->comp_index = 1;
+	}
+	return ret;
+}
+
+/* retrieve the meter level values from URB message */
+static void get_meter_levels_from_urb(int s,
+	struct snd_us16x08_meter_store *store,
+	u8 *meter_urb)
+{
+	int val = MUC2(meter_urb, s) + (MUC3(meter_urb, s) << 8);
+	int ch = MUB2(meter_urb, s) - 1;
+
+	if (ch < 0)
+		return;
+
+	if (MUA0(meter_urb, s) == 0x61 && MUA1(meter_urb, s) == 0x02 &&
+		MUA2(meter_urb, s) == 0x04 && MUB0(meter_urb, s) == 0x62) {
+		if (ch < SND_US16X08_MAX_CHANNELS) {
+			if (MUC0(meter_urb, s) == 0x72)
+				store->meter_level[ch] = val;
+			if (MUC0(meter_urb, s) == 0xb2)
+				store->comp_level[ch] = val;
+		}
+	}
+	if (MUA0(meter_urb, s) == 0x61 && MUA1(meter_urb, s) == 0x02 &&
+		MUA2(meter_urb, s) == 0x02 && MUB0(meter_urb, s) == 0x62) {
+		if (ch < ARRAY_SIZE(store->master_level))
+			store->master_level[ch] = val;
+	}
+}
+
+/* Function to retrieve current meter values from the device.
+ *
+ * The device needs to be polled for meter values with an initial
+ * requests. It will return with a sequence of different meter value
+ * packages. The first request (case 0:) initiate this meter response sequence.
+ * After the third response, an additional request can be placed,
+ * to retrieve compressor reduction level value for given channel. This round
+ * trip channel selector will skip all inactive compressors.
+ * A mixer can interrupt this round-trip by selecting one ore two (stereo-link)
+ * specific channels.
+ */
+static int snd_us16x08_meter_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	int i, set;
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_audio *chip = elem->head.mixer->chip;
+	struct snd_us16x08_meter_store *store = elem->private_data;
+	u8 meter_urb[64] = {0};
+
+	switch (kcontrol->private_value) {
+	case 0: {
+		char tmp[sizeof(mix_init_msg1)];
+
+		memcpy(tmp, mix_init_msg1, sizeof(mix_init_msg1));
+		snd_us16x08_send_urb(chip, tmp, 4);
+		snd_us16x08_recv_urb(chip, meter_urb,
+			sizeof(meter_urb));
+		kcontrol->private_value++;
+		break;
+	}
+	case 1:
+		snd_us16x08_recv_urb(chip, meter_urb,
+			sizeof(meter_urb));
+		kcontrol->private_value++;
+		break;
+	case 2:
+		snd_us16x08_recv_urb(chip, meter_urb,
+			sizeof(meter_urb));
+		kcontrol->private_value++;
+		break;
+	case 3: {
+		char tmp[sizeof(mix_init_msg2)];
+
+		memcpy(tmp, mix_init_msg2, sizeof(mix_init_msg2));
+		tmp[2] = snd_get_meter_comp_index(store);
+		snd_us16x08_send_urb(chip, tmp, 10);
+		snd_us16x08_recv_urb(chip, meter_urb,
+			sizeof(meter_urb));
+		kcontrol->private_value = 0;
+		break;
+	}
+	}
+
+	for (set = 0; set < 6; set++)
+		get_meter_levels_from_urb(set, store, meter_urb);
+
+	for (i = 0; i < SND_US16X08_MAX_CHANNELS; i++) {
+		ucontrol->value.integer.value[i] =
+			store ? store->meter_level[i] : 0;
+	}
+
+	ucontrol->value.integer.value[i++] = store ? store->master_level[0] : 0;
+	ucontrol->value.integer.value[i++] = store ? store->master_level[1] : 0;
+
+	for (i = 2; i < SND_US16X08_MAX_CHANNELS + 2; i++)
+		ucontrol->value.integer.value[i + SND_US16X08_MAX_CHANNELS] =
+		store ? store->comp_level[i - 2] : 0;
+
+	return 1;
+}
+
+static int snd_us16x08_meter_put(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct usb_mixer_elem_info *elem = snd_kcontrol_chip(kcontrol);
+	struct snd_us16x08_meter_store *store = elem->private_data;
+	int val;
+
+	val = ucontrol->value.integer.value[0];
+
+	/* sanity check */
+	if (val < 0 || val >= SND_US16X08_MAX_CHANNELS)
+		return -EINVAL;
+
+	store->comp_active_index = val;
+	store->comp_index = val;
+
+	return 1;
+}
+
+static const struct snd_kcontrol_new snd_us16x08_ch_boolean_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_switch_info,
+	.get = snd_us16x08_channel_get,
+	.put = snd_us16x08_channel_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 1)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_ch_int_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_channel_get,
+	.put = snd_us16x08_channel_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_FADER_BIAS, 1, 0, 133)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_pan_int_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_channel_get,
+	.put = snd_us16x08_channel_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_FADER_BIAS, 1, 0, 255)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_master_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 1,
+	.info = snd_us16x08_master_info,
+	.get = snd_us16x08_master_get,
+	.put = snd_us16x08_master_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_FADER_BIAS, 1, 0, 133)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_route_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 8,
+	.info = snd_us16x08_route_info,
+	.get = snd_us16x08_route_get,
+	.put = snd_us16x08_route_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 9)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_bus_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 1,
+	.info = snd_us16x08_switch_info,
+	.get = snd_us16x08_bus_get,
+	.put = snd_us16x08_bus_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 1)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_compswitch_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_switch_info,
+	.get = snd_us16x08_comp_get,
+	.put = snd_us16x08_comp_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 1)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_comp_threshold_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_comp_get,
+	.put = snd_us16x08_comp_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_COMP_THRESHOLD_BIAS, 1,
+	0, 0x20)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_comp_ratio_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_comp_get,
+	.put = snd_us16x08_comp_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0,
+	sizeof(ratio_map) - 1), /*max*/
+};
+
+static const struct snd_kcontrol_new snd_us16x08_comp_gain_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_comp_get,
+	.put = snd_us16x08_comp_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 0x14)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_comp_attack_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_comp_get,
+	.put = snd_us16x08_comp_put,
+	.private_value =
+	SND_US16X08_KCSET(SND_US16X08_COMP_ATTACK_BIAS, 1, 0, 0xc6),
+};
+
+static const struct snd_kcontrol_new snd_us16x08_comp_release_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_comp_get,
+	.put = snd_us16x08_comp_put,
+	.private_value =
+	SND_US16X08_KCSET(SND_US16X08_COMP_RELEASE_BIAS, 1, 0, 0x63),
+};
+
+static const struct snd_kcontrol_new snd_us16x08_eq_gain_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_eq_get,
+	.put = snd_us16x08_eq_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 24),
+};
+
+static const struct snd_kcontrol_new snd_us16x08_eq_low_freq_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_eq_get,
+	.put = snd_us16x08_eq_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 0x1F),
+};
+
+static const struct snd_kcontrol_new snd_us16x08_eq_mid_freq_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_eq_get,
+	.put = snd_us16x08_eq_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 0x3F)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_eq_mid_width_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_eq_get,
+	.put = snd_us16x08_eq_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 0x06)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_eq_high_freq_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_mix_info,
+	.get = snd_us16x08_eq_get,
+	.put = snd_us16x08_eq_put,
+	.private_value =
+	SND_US16X08_KCSET(SND_US16X08_EQ_HIGHFREQ_BIAS, 1, 0, 0x1F)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_eq_switch_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 16,
+	.info = snd_us16x08_switch_info,
+	.get = snd_us16x08_eqswitch_get,
+	.put = snd_us16x08_eqswitch_put,
+	.private_value = SND_US16X08_KCSET(SND_US16X08_NO_BIAS, 1, 0, 1)
+};
+
+static const struct snd_kcontrol_new snd_us16x08_meter_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
+	.count = 1,
+	.info = snd_us16x08_meter_info,
+	.get = snd_us16x08_meter_get,
+	.put = snd_us16x08_meter_put
+};
+
+/* control store preparation */
+
+/* setup compressor store and assign default value */
+static struct snd_us16x08_comp_store *snd_us16x08_create_comp_store(void)
+{
+	int i;
+	struct snd_us16x08_comp_store *tmp;
+
+	tmp = kmalloc_obj(*tmp);
+	if (!tmp)
+		return NULL;
+
+	for (i = 0; i < SND_US16X08_MAX_CHANNELS; i++) {
+		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_THRESHOLD)][i]
+			= 0x20;
+		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_RATIO)][i] = 0x00;
+		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_GAIN)][i] = 0x00;
+		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_SWITCH)][i] = 0x00;
+		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_ATTACK)][i] = 0x00;
+		tmp->val[COMP_STORE_IDX(SND_US16X08_ID_COMP_RELEASE)][i] = 0x00;
+	}
+	return tmp;
+}
+
+/* setup EQ store and assign default values */
+static struct snd_us16x08_eq_store *snd_us16x08_create_eq_store(void)
+{
+	int i, b_idx;
+	struct snd_us16x08_eq_store *tmp;
+
+	tmp = kmalloc_obj(*tmp);
+	if (!tmp)
+		return NULL;
+
+	for (i = 0; i < SND_US16X08_MAX_CHANNELS; i++) {
+		for (b_idx = 0; b_idx < SND_US16X08_ID_EQ_BAND_COUNT; b_idx++) {
+			tmp->val[b_idx][0][i] = 0x0c;
+			tmp->val[b_idx][3][i] = 0x00;
+			switch (b_idx) {
+			case 0: /* EQ Low */
+				tmp->val[b_idx][1][i] = 0x05;
+				tmp->val[b_idx][2][i] = 0xff;
+				break;
+			case 1: /* EQ Mid low */
+				tmp->val[b_idx][1][i] = 0x0e;
+				tmp->val[b_idx][2][i] = 0x02;
+				break;
+			case 2: /* EQ Mid High */
+				tmp->val[b_idx][1][i] = 0x1b;
+				tmp->val[b_idx][2][i] = 0x02;
+				break;
+			case 3: /* EQ High */
+				tmp->val[b_idx][1][i] = 0x2f
+					- SND_US16X08_EQ_HIGHFREQ_BIAS;
+				tmp->val[b_idx][2][i] = 0xff;
+				break;
+			}
+		}
+	}
+	return tmp;
+}
+
+static struct snd_us16x08_meter_store *snd_us16x08_create_meter_store(void)
+{
+	struct snd_us16x08_meter_store *tmp;
+
+	tmp = kzalloc_obj(*tmp);
+	if (!tmp)
+		return NULL;
+	tmp->comp_index = 1;
+	tmp->comp_active_index = 0;
+	return tmp;
+}
+
+/* release elem->private_free as well; called only once for each *_store */
+static void elem_private_free(struct snd_kcontrol *kctl)
+{
+	struct usb_mixer_elem_info *elem = kctl->private_data;
+
+	if (elem)
+		kfree(elem->private_data);
+	kfree(elem);
+	kctl->private_data = NULL;
+}
+
+static int add_new_ctl(struct usb_mixer_interface *mixer,
+	const struct snd_kcontrol_new *ncontrol,
+	int index, int val_type, int channels,
+	const char *name, void *opt,
+	bool do_private_free,
+	struct usb_mixer_elem_info **elem_ret)
+{
+	struct snd_kcontrol *kctl;
+	struct usb_mixer_elem_info *elem;
+	int err;
+
+	usb_audio_dbg(mixer->chip, "us16x08 add mixer %s\n", name);
+
+	elem = kzalloc_obj(*elem);
+	if (!elem)
+		return -ENOMEM;
+
+	elem->head.mixer = mixer;
+	elem->head.resume = NULL;
+	elem->control = 0;
+	elem->idx_off = 0;
+	elem->head.id = index;
+	elem->val_type = val_type;
+	elem->channels = channels;
+	elem->private_data = opt;
+
+	kctl = snd_ctl_new1(ncontrol, elem);
+	if (!kctl) {
+		kfree(elem);
+		return -ENOMEM;
+	}
+
+	if (do_private_free)
+		kctl->private_free = elem_private_free;
+	else
+		kctl->private_free = snd_usb_mixer_elem_free;
+
+	strscpy(kctl->id.name, name, sizeof(kctl->id.name));
+
+	err = snd_usb_mixer_add_control(&elem->head, kctl);
+	if (err < 0)
+		return err;
+
+	if (elem_ret)
+		*elem_ret = elem;
+
+	return 0;
+}
+
+/* table of EQ controls */
+static const struct snd_us16x08_control_params eq_controls[] = {
+	{ /* EQ switch */
+		.kcontrol_new = &snd_us16x08_eq_switch_ctl,
+		.control_id = SND_US16X08_ID_EQENABLE,
+		.type = USB_MIXER_BOOLEAN,
+		.num_channels = 16,
+		.name = "EQ Switch",
+	},
+	{ /* EQ low gain */
+		.kcontrol_new = &snd_us16x08_eq_gain_ctl,
+		.control_id = SND_US16X08_ID_EQLOWLEVEL,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ Low Volume",
+	},
+	{ /* EQ low freq */
+		.kcontrol_new = &snd_us16x08_eq_low_freq_ctl,
+		.control_id = SND_US16X08_ID_EQLOWFREQ,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ Low Frequency",
+	},
+	{ /* EQ mid low gain */
+		.kcontrol_new = &snd_us16x08_eq_gain_ctl,
+		.control_id = SND_US16X08_ID_EQLOWMIDLEVEL,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ MidLow Volume",
+	},
+	{ /* EQ mid low freq */
+		.kcontrol_new = &snd_us16x08_eq_mid_freq_ctl,
+		.control_id = SND_US16X08_ID_EQLOWMIDFREQ,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ MidLow Frequency",
+	},
+	{ /* EQ mid low Q */
+		.kcontrol_new = &snd_us16x08_eq_mid_width_ctl,
+		.control_id = SND_US16X08_ID_EQLOWMIDWIDTH,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ MidLow Q",
+	},
+	{ /* EQ mid high gain */
+		.kcontrol_new = &snd_us16x08_eq_gain_ctl,
+		.control_id = SND_US16X08_ID_EQHIGHMIDLEVEL,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ MidHigh Volume",
+	},
+	{ /* EQ mid high freq */
+		.kcontrol_new = &snd_us16x08_eq_mid_freq_ctl,
+		.control_id = SND_US16X08_ID_EQHIGHMIDFREQ,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ MidHigh Frequency",
+	},
+	{ /* EQ mid high Q */
+		.kcontrol_new = &snd_us16x08_eq_mid_width_ctl,
+		.control_id = SND_US16X08_ID_EQHIGHMIDWIDTH,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ MidHigh Q",
+	},
+	{ /* EQ high gain */
+		.kcontrol_new = &snd_us16x08_eq_gain_ctl,
+		.control_id = SND_US16X08_ID_EQHIGHLEVEL,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ High Volume",
+	},
+	{ /* EQ low freq */
+		.kcontrol_new = &snd_us16x08_eq_high_freq_ctl,
+		.control_id = SND_US16X08_ID_EQHIGHFREQ,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "EQ High Frequency",
+	},
+};
+
+/* table of compressor controls */
+static const struct snd_us16x08_control_params comp_controls[] = {
+	{ /* Comp enable */
+		.kcontrol_new = &snd_us16x08_compswitch_ctl,
+		.control_id = SND_US16X08_ID_COMP_SWITCH,
+		.type = USB_MIXER_BOOLEAN,
+		.num_channels = 16,
+		.name = "Compressor Switch",
+	},
+	{ /* Comp threshold */
+		.kcontrol_new = &snd_us16x08_comp_threshold_ctl,
+		.control_id = SND_US16X08_ID_COMP_THRESHOLD,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "Compressor Threshold Volume",
+	},
+	{ /* Comp ratio */
+		.kcontrol_new = &snd_us16x08_comp_ratio_ctl,
+		.control_id = SND_US16X08_ID_COMP_RATIO,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "Compressor Ratio",
+	},
+	{ /* Comp attack */
+		.kcontrol_new = &snd_us16x08_comp_attack_ctl,
+		.control_id = SND_US16X08_ID_COMP_ATTACK,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "Compressor Attack",
+	},
+	{ /* Comp release */
+		.kcontrol_new = &snd_us16x08_comp_release_ctl,
+		.control_id = SND_US16X08_ID_COMP_RELEASE,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "Compressor Release",
+	},
+	{ /* Comp gain */
+		.kcontrol_new = &snd_us16x08_comp_gain_ctl,
+		.control_id = SND_US16X08_ID_COMP_GAIN,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "Compressor Volume",
+	},
+};
+
+/* table of channel controls */
+static const struct snd_us16x08_control_params channel_controls[] = {
+	{ /* Phase */
+		.kcontrol_new = &snd_us16x08_ch_boolean_ctl,
+		.control_id = SND_US16X08_ID_PHASE,
+		.type = USB_MIXER_BOOLEAN,
+		.num_channels = 16,
+		.name = "Phase Switch",
+		.default_val = 0
+	},
+	{ /* Fader */
+		.kcontrol_new = &snd_us16x08_ch_int_ctl,
+		.control_id = SND_US16X08_ID_FADER,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "Line Volume",
+		.default_val = 127
+	},
+	{ /* Mute */
+		.kcontrol_new = &snd_us16x08_ch_boolean_ctl,
+		.control_id = SND_US16X08_ID_MUTE,
+		.type = USB_MIXER_BOOLEAN,
+		.num_channels = 16,
+		.name = "Mute Switch",
+		.default_val = 0
+	},
+	{ /* Pan */
+		.kcontrol_new = &snd_us16x08_pan_int_ctl,
+		.control_id = SND_US16X08_ID_PAN,
+		.type = USB_MIXER_U16,
+		.num_channels = 16,
+		.name = "Pan Left-Right Volume",
+		.default_val = 127
+	},
+};
+
+/* table of master controls */
+static const struct snd_us16x08_control_params master_controls[] = {
+	{ /* Master */
+		.kcontrol_new = &snd_us16x08_master_ctl,
+		.control_id = SND_US16X08_ID_FADER,
+		.type = USB_MIXER_U8,
+		.num_channels = 16,
+		.name = "Master Volume",
+		.default_val = 127
+	},
+	{ /* Bypass */
+		.kcontrol_new = &snd_us16x08_bus_ctl,
+		.control_id = SND_US16X08_ID_BYPASS,
+		.type = USB_MIXER_BOOLEAN,
+		.num_channels = 16,
+		.name = "DSP Bypass Switch",
+		.default_val = 0
+	},
+	{ /* Buss out */
+		.kcontrol_new = &snd_us16x08_bus_ctl,
+		.control_id = SND_US16X08_ID_BUSS_OUT,
+		.type = USB_MIXER_BOOLEAN,
+		.num_channels = 16,
+		.name = "Buss Out Switch",
+		.default_val = 0
+	},
+	{ /* Master mute */
+		.kcontrol_new = &snd_us16x08_bus_ctl,
+		.control_id = SND_US16X08_ID_MUTE,
+		.type = USB_MIXER_BOOLEAN,
+		.num_channels = 16,
+		.name = "Master Mute Switch",
+		.default_val = 0
+	},
+
+};
+
+int snd_us16x08_controls_create(struct usb_mixer_interface *mixer)
+{
+	int i, j;
+	int err;
+	struct usb_mixer_elem_info *elem;
+	struct snd_us16x08_comp_store *comp_store;
+	struct snd_us16x08_meter_store *meter_store;
+	struct snd_us16x08_eq_store *eq_store;
+
+	/* just check for non-MIDI interface */
+	if (mixer->hostif->desc.bInterfaceNumber == 3) {
+
+		/* add routing control */
+		err = add_new_ctl(mixer, &snd_us16x08_route_ctl,
+			SND_US16X08_ID_ROUTE, USB_MIXER_U8, 8, "Line Out Route",
+			NULL, false, &elem);
+		if (err < 0) {
+			usb_audio_dbg(mixer->chip,
+				"Failed to create route control, err:%d\n",
+				err);
+			return err;
+		}
+		for (i = 0; i < 8; i++)
+			elem->cache_val[i] = i < 2 ? i : i + 2;
+		elem->cached = 0xff;
+
+		/* create compressor mixer elements */
+		comp_store = snd_us16x08_create_comp_store();
+		if (!comp_store)
+			return -ENOMEM;
+
+		/* add master controls */
+		for (i = 0; i < ARRAY_SIZE(master_controls); i++) {
+
+			err = add_new_ctl(mixer,
+				master_controls[i].kcontrol_new,
+				master_controls[i].control_id,
+				master_controls[i].type,
+				master_controls[i].num_channels,
+				master_controls[i].name,
+				comp_store,
+				i == 0, /* release comp_store only once */
+				&elem);
+			if (err < 0)
+				return err;
+			elem->cache_val[0] = master_controls[i].default_val;
+			elem->cached = 1;
+		}
+
+		/* add channel controls */
+		for (i = 0; i < ARRAY_SIZE(channel_controls); i++) {
+
+			err = add_new_ctl(mixer,
+				channel_controls[i].kcontrol_new,
+				channel_controls[i].control_id,
+				channel_controls[i].type,
+				channel_controls[i].num_channels,
+				channel_controls[i].name,
+				comp_store,
+				false, &elem);
+			if (err < 0)
+				return err;
+			for (j = 0; j < SND_US16X08_MAX_CHANNELS; j++) {
+				elem->cache_val[j] =
+					channel_controls[i].default_val;
+			}
+			elem->cached = 0xffff;
+		}
+
+		/* create eq store */
+		eq_store = snd_us16x08_create_eq_store();
+		if (!eq_store)
+			return -ENOMEM;
+
+		/* add EQ controls */
+		for (i = 0; i < ARRAY_SIZE(eq_controls); i++) {
+
+			err = add_new_ctl(mixer,
+				eq_controls[i].kcontrol_new,
+				eq_controls[i].control_id,
+				eq_controls[i].type,
+				eq_controls[i].num_channels,
+				eq_controls[i].name,
+				eq_store,
+				i == 0, /* release eq_store only once */
+				NULL);
+			if (err < 0)
+				return err;
+		}
+
+		/* add compressor controls */
+		for (i = 0; i < ARRAY_SIZE(comp_controls); i++) {
+
+			err = add_new_ctl(mixer,
+				comp_controls[i].kcontrol_new,
+				comp_controls[i].control_id,
+				comp_controls[i].type,
+				comp_controls[i].num_channels,
+				comp_controls[i].name,
+				comp_store,
+				false, NULL);
+			if (err < 0)
+				return err;
+		}
+
+		/* create meters store */
+		meter_store = snd_us16x08_create_meter_store();
+		if (!meter_store)
+			return -ENOMEM;
+
+		/* meter function 'get' must access to compressor store
+		 * so place a reference here
+		 */
+		meter_store->comp_store = comp_store;
+		err = add_new_ctl(mixer, &snd_us16x08_meter_ctl,
+			SND_US16X08_ID_METER, USB_MIXER_U16, 0, "Level Meter",
+			meter_store, true, NULL);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
diff --git a/sound/usb/mixer_us16x08.h b/sound/usb/mixer_us16x08.h
new file mode 100644
index 000000000..7b8583dd3
--- /dev/null
+++ b/sound/usb/mixer_us16x08.h
@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USB_MIXER_US16X08_H
+#define __USB_MIXER_US16X08_H
+
+#define SND_US16X08_MAX_CHANNELS 16
+
+/* define some bias, cause some alsa-mixers wont work with
+ * negative ranges or if mixer-min != 0
+ */
+#define SND_US16X08_NO_BIAS 0
+#define SND_US16X08_FADER_BIAS 127
+#define SND_US16X08_EQ_HIGHFREQ_BIAS 0x20
+#define SND_US16X08_COMP_THRESHOLD_BIAS 0x20
+#define SND_US16X08_COMP_ATTACK_BIAS 2
+#define SND_US16X08_COMP_RELEASE_BIAS 1
+
+/* get macro for components of kcontrol private_value */
+#define SND_US16X08_KCBIAS(x) (((x)->private_value >> 24) & 0xff)
+#define SND_US16X08_KCSTEP(x) (((x)->private_value >> 16) & 0xff)
+#define SND_US16X08_KCMIN(x) (((x)->private_value >> 8) & 0xff)
+#define SND_US16X08_KCMAX(x) (((x)->private_value >> 0) & 0xff)
+/* set macro for kcontrol private_value */
+#define SND_US16X08_KCSET(bias, step, min, max)  \
+	(((bias) << 24) | ((step) << 16) | ((min) << 8) | (max))
+
+/* the URB request/type to control Tascam mixers */
+#define SND_US16X08_URB_REQUEST 0x1D
+#define SND_US16X08_URB_REQUESTTYPE 0x40
+
+/* the URB params to retrieve meter ranges */
+#define SND_US16X08_URB_METER_REQUEST       0x1e
+#define SND_US16X08_URB_METER_REQUESTTYPE   0xc0
+
+#define MUA0(x, y) ((x)[(y) * 10 + 4])
+#define MUA1(x, y) ((x)[(y) * 10 + 5])
+#define MUA2(x, y) ((x)[(y) * 10 + 6])
+#define MUB0(x, y) ((x)[(y) * 10 + 7])
+#define MUB1(x, y) ((x)[(y) * 10 + 8])
+#define MUB2(x, y) ((x)[(y) * 10 + 9])
+#define MUC0(x, y) ((x)[(y) * 10 + 10])
+#define MUC1(x, y) ((x)[(y) * 10 + 11])
+#define MUC2(x, y) ((x)[(y) * 10 + 12])
+#define MUC3(x, y) ((x)[(y) * 10 + 13])
+
+/* Common Channel control IDs */
+#define SND_US16X08_ID_BYPASS 0x45
+#define SND_US16X08_ID_BUSS_OUT 0x44
+#define SND_US16X08_ID_PHASE 0x85
+#define SND_US16X08_ID_MUTE 0x83
+#define SND_US16X08_ID_FADER 0x81
+#define SND_US16X08_ID_PAN 0x82
+#define SND_US16X08_ID_METER 0xB1
+
+#define SND_US16X08_ID_EQ_BAND_COUNT 4
+#define SND_US16X08_ID_EQ_PARAM_COUNT 4
+
+/* EQ level IDs */
+#define SND_US16X08_ID_EQLOWLEVEL 0x01
+#define SND_US16X08_ID_EQLOWMIDLEVEL 0x02
+#define SND_US16X08_ID_EQHIGHMIDLEVEL 0x03
+#define SND_US16X08_ID_EQHIGHLEVEL 0x04
+
+/* EQ frequence IDs */
+#define SND_US16X08_ID_EQLOWFREQ 0x11
+#define SND_US16X08_ID_EQLOWMIDFREQ 0x12
+#define SND_US16X08_ID_EQHIGHMIDFREQ 0x13
+#define SND_US16X08_ID_EQHIGHFREQ 0x14
+
+/* EQ width IDs */
+#define SND_US16X08_ID_EQLOWMIDWIDTH 0x22
+#define SND_US16X08_ID_EQHIGHMIDWIDTH 0x23
+
+#define SND_US16X08_ID_EQENABLE 0x30
+
+#define EQ_STORE_BAND_IDX(x) ((x) & 0xf)
+#define EQ_STORE_PARAM_IDX(x) (((x) & 0xf0) >> 4)
+
+#define SND_US16X08_ID_ROUTE 0x00
+
+/* Compressor Ids */
+#define SND_US16X08_ID_COMP_BASE	0x32
+#define SND_US16X08_ID_COMP_THRESHOLD	SND_US16X08_ID_COMP_BASE
+#define SND_US16X08_ID_COMP_RATIO	(SND_US16X08_ID_COMP_BASE + 1)
+#define SND_US16X08_ID_COMP_ATTACK	(SND_US16X08_ID_COMP_BASE + 2)
+#define SND_US16X08_ID_COMP_RELEASE	(SND_US16X08_ID_COMP_BASE + 3)
+#define SND_US16X08_ID_COMP_GAIN	(SND_US16X08_ID_COMP_BASE + 4)
+#define SND_US16X08_ID_COMP_SWITCH	(SND_US16X08_ID_COMP_BASE + 5)
+#define SND_US16X08_ID_COMP_COUNT	6
+
+#define COMP_STORE_IDX(x) ((x) - SND_US16X08_ID_COMP_BASE)
+
+struct snd_us16x08_eq_store {
+	u8 val[SND_US16X08_ID_EQ_BAND_COUNT][SND_US16X08_ID_EQ_PARAM_COUNT]
+		[SND_US16X08_MAX_CHANNELS];
+};
+
+struct snd_us16x08_comp_store {
+	u8 val[SND_US16X08_ID_COMP_COUNT][SND_US16X08_MAX_CHANNELS];
+};
+
+struct snd_us16x08_meter_store {
+	int meter_level[SND_US16X08_MAX_CHANNELS];
+	int master_level[2]; /* level of meter for master output */
+	int comp_index; /* round trip channel selector */
+	int comp_active_index; /* channel select from user space mixer */
+	int comp_level[16]; /* compressor reduction level */
+	struct snd_us16x08_comp_store *comp_store;
+};
+
+struct snd_us16x08_control_params {
+	const struct snd_kcontrol_new *kcontrol_new;
+	int control_id;
+	int type;
+	int num_channels;
+	const char *name;
+	int default_val;
+};
+
+#define snd_us16x08_switch_info snd_ctl_boolean_mono_info
+
+int snd_us16x08_controls_create(struct usb_mixer_interface *mixer);
+#endif /* __USB_MIXER_US16X08_H */
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
new file mode 100644
index 000000000..682b6c1fe
--- /dev/null
+++ b/sound/usb/pcm.c
@@ -0,0 +1,1833 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/bitrev.h>
+#include <linux/ratelimit.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "quirks.h"
+#include "endpoint.h"
+#include "helper.h"
+#include "pcm.h"
+#include "clock.h"
+#include "power.h"
+#include "media.h"
+#include "implicit.h"
+
+#define SUBSTREAM_FLAG_DATA_EP_STARTED	0
+#define SUBSTREAM_FLAG_SYNC_EP_STARTED	1
+
+/* return the estimated delay based on USB frame counters */
+static snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
+					   struct snd_pcm_runtime *runtime)
+{
+	unsigned int current_frame_number;
+	unsigned int frame_diff;
+	int est_delay;
+	int queued;
+
+	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
+		queued = bytes_to_frames(runtime, subs->inflight_bytes);
+		if (!queued)
+			return 0;
+	} else if (!subs->running) {
+		return 0;
+	}
+
+	current_frame_number = usb_get_current_frame_number(subs->dev);
+	/*
+	 * HCD implementations use different widths, use lower 8 bits.
+	 * The delay will be managed up to 256ms, which is more than
+	 * enough
+	 */
+	frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;
+
+	/* Approximation based on number of samples per USB frame (ms),
+	   some truncation for 44.1 but the estimate is good enough */
+	est_delay = frame_diff * runtime->rate / 1000;
+
+	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
+		est_delay = queued - est_delay;
+		if (est_delay < 0)
+			est_delay = 0;
+	}
+
+	return est_delay;
+}
+
+/*
+ * return the current pcm pointer.  just based on the hwptr_done value.
+ */
+static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usb_substream *subs = runtime->private_data;
+	unsigned int hwptr_done;
+
+	if (atomic_read(&subs->stream->chip->shutdown))
+		return SNDRV_PCM_POS_XRUN;
+	scoped_guard(spinlock, &subs->lock) {
+		hwptr_done = subs->hwptr_done;
+		runtime->delay = snd_usb_pcm_delay(subs, runtime);
+	}
+	return bytes_to_frames(runtime, hwptr_done);
+}
+
+/*
+ * find a matching audio format
+ */
+static const struct audioformat *
+find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,
+	    unsigned int rate, unsigned int channels, bool strict_match,
+	    struct snd_usb_substream *subs)
+{
+	const struct audioformat *fp;
+	const struct audioformat *found = NULL;
+	int cur_attr = 0, attr;
+
+	list_for_each_entry(fp, fmt_list_head, list) {
+		if (strict_match) {
+			if (!(fp->formats & pcm_format_to_bits(format)))
+				continue;
+			if (fp->channels != channels)
+				continue;
+		}
+		if (rate < fp->rate_min || rate > fp->rate_max)
+			continue;
+		if (!(fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
+			unsigned int i;
+			for (i = 0; i < fp->nr_rates; i++)
+				if (fp->rate_table[i] == rate)
+					break;
+			if (i >= fp->nr_rates)
+				continue;
+		}
+		attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
+		if (!found) {
+			found = fp;
+			cur_attr = attr;
+			continue;
+		}
+		/* avoid async out and adaptive in if the other method
+		 * supports the same format.
+		 * this is a workaround for the case like
+		 * M-audio audiophile USB.
+		 */
+		if (subs && attr != cur_attr) {
+			if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
+			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
+			    (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
+			     subs->direction == SNDRV_PCM_STREAM_CAPTURE))
+				continue;
+			if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
+			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
+			    (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
+			     subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
+				found = fp;
+				cur_attr = attr;
+				continue;
+			}
+		}
+		/* find the format with the largest max. packet size */
+		if (fp->maxpacksize > found->maxpacksize) {
+			found = fp;
+			cur_attr = attr;
+		}
+	}
+	return found;
+}
+
+const struct audioformat *
+snd_usb_find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,
+		    unsigned int rate, unsigned int channels, bool strict_match,
+		    struct snd_usb_substream *subs)
+{
+	return find_format(fmt_list_head, format, rate, channels, strict_match,
+			subs);
+}
+EXPORT_SYMBOL_GPL(snd_usb_find_format);
+
+static const struct audioformat *
+find_substream_format(struct snd_usb_substream *subs,
+		      const struct snd_pcm_hw_params *params)
+{
+	return find_format(&subs->fmt_list, params_format(params),
+			   params_rate(params), params_channels(params),
+			   true, subs);
+}
+
+const struct audioformat *
+snd_usb_find_substream_format(struct snd_usb_substream *subs,
+			      const struct snd_pcm_hw_params *params)
+{
+	return find_substream_format(subs, params);
+}
+EXPORT_SYMBOL_GPL(snd_usb_find_substream_format);
+
+bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *subs)
+{
+	const struct audioformat *fp;
+	struct snd_usb_audio *chip;
+	int rate = -1;
+
+	if (!subs)
+		return false;
+	chip = subs->stream->chip;
+	if (!(chip->quirk_flags & QUIRK_FLAG_FIXED_RATE))
+		return false;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
+			return false;
+		if (fp->nr_rates < 1)
+			continue;
+		if (fp->nr_rates > 1)
+			return false;
+		if (rate < 0) {
+			rate = fp->rate_table[0];
+			continue;
+		}
+		if (rate != fp->rate_table[0])
+			return false;
+	}
+	return true;
+}
+
+static int init_pitch_v1(struct snd_usb_audio *chip, int ep)
+{
+	struct usb_device *dev = chip->dev;
+	unsigned char data[1];
+	int err;
+
+	data[0] = 1;
+	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
+			      USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
+			      UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
+			      data, sizeof(data));
+	return err;
+}
+
+static int init_pitch_v2(struct snd_usb_audio *chip, int ep)
+{
+	struct usb_device *dev = chip->dev;
+	unsigned char data[1];
+	int err;
+
+	data[0] = 1;
+	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
+			      UAC2_EP_CS_PITCH << 8, 0,
+			      data, sizeof(data));
+	return err;
+}
+
+/*
+ * initialize the pitch control and sample rate
+ */
+int snd_usb_init_pitch(struct snd_usb_audio *chip,
+		       const struct audioformat *fmt)
+{
+	int err;
+
+	/* if endpoint doesn't have pitch control, bail out */
+	if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
+		return 0;
+
+	usb_audio_dbg(chip, "enable PITCH for EP 0x%x\n", fmt->endpoint);
+
+	switch (fmt->protocol) {
+	case UAC_VERSION_1:
+		err = init_pitch_v1(chip, fmt->endpoint);
+		break;
+	case UAC_VERSION_2:
+		err = init_pitch_v2(chip, fmt->endpoint);
+		break;
+	default:
+		return 0;
+	}
+
+	if (err < 0) {
+		usb_audio_err(chip, "failed to enable PITCH for EP 0x%x\n",
+			      fmt->endpoint);
+		return err;
+	}
+
+	return 0;
+}
+
+static bool stop_endpoints(struct snd_usb_substream *subs, bool keep_pending)
+{
+	bool stopped = 0;
+
+	if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
+		snd_usb_endpoint_stop(subs->sync_endpoint, keep_pending);
+		stopped = true;
+	}
+	if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
+		snd_usb_endpoint_stop(subs->data_endpoint, keep_pending);
+		stopped = true;
+	}
+	return stopped;
+}
+
+static int start_endpoints(struct snd_usb_substream *subs)
+{
+	int err;
+
+	if (!subs->data_endpoint)
+		return -EINVAL;
+
+	if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
+		err = snd_usb_endpoint_start(subs->data_endpoint);
+		if (err < 0) {
+			clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
+			goto error;
+		}
+	}
+
+	if (subs->sync_endpoint &&
+	    !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
+		err = snd_usb_endpoint_start(subs->sync_endpoint);
+		if (err < 0) {
+			clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
+			goto error;
+		}
+	}
+
+	return 0;
+
+ error:
+	stop_endpoints(subs, false);
+	return err;
+}
+
+static void sync_pending_stops(struct snd_usb_substream *subs)
+{
+	snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
+	snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);
+}
+
+/* PCM sync_stop callback */
+static int snd_usb_pcm_sync_stop(struct snd_pcm_substream *substream)
+{
+	struct snd_usb_substream *subs = substream->runtime->private_data;
+
+	sync_pending_stops(subs);
+	return 0;
+}
+
+/* Set up sync endpoint */
+int snd_usb_audioformat_set_sync_ep(struct snd_usb_audio *chip,
+				    struct audioformat *fmt)
+{
+	struct usb_device *dev = chip->dev;
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	unsigned int ep, attr, sync_attr;
+	bool is_playback;
+	int err;
+
+	if (fmt->sync_ep)
+		return 0; /* already set up */
+
+	alts = snd_usb_get_host_interface(chip, fmt->iface, fmt->altsetting);
+	if (!alts)
+		return 0;
+	altsd = get_iface_desc(alts);
+
+	err = snd_usb_parse_implicit_fb_quirk(chip, fmt, alts);
+	if (err > 0)
+		return 0; /* matched */
+
+	/*
+	 * Generic sync EP handling
+	 */
+
+	if (fmt->ep_idx > 0 || altsd->bNumEndpoints < 2)
+		return 0;
+
+	is_playback = !(get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN);
+	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
+	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
+			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
+	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
+		return 0;
+
+	sync_attr = get_endpoint(alts, 1)->bmAttributes;
+
+	/*
+	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
+	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
+	 * error fall back to SYNC mode and don't create sync endpoint
+	 */
+
+	/* check sync-pipe endpoint */
+	/* ... and check descriptor size before accessing bSynchAddress
+	   because there is a version of the SB Audigy 2 NX firmware lacking
+	   the audio fields in the endpoint descriptors */
+	if ((sync_attr & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
+	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
+	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
+		dev_err(&dev->dev,
+			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
+			   fmt->iface, fmt->altsetting,
+			   get_endpoint(alts, 1)->bmAttributes,
+			   get_endpoint(alts, 1)->bLength,
+			   get_endpoint(alts, 1)->bSynchAddress);
+		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
+			return 0;
+		return -EINVAL;
+	}
+	ep = get_endpoint(alts, 1)->bEndpointAddress;
+	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
+	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
+	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
+	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
+		dev_err(&dev->dev,
+			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
+			   fmt->iface, fmt->altsetting,
+			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
+		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
+			return 0;
+		return -EINVAL;
+	}
+
+	fmt->sync_ep = ep;
+	fmt->sync_iface = altsd->bInterfaceNumber;
+	fmt->sync_altsetting = altsd->bAlternateSetting;
+	fmt->sync_ep_idx = 1;
+	if ((sync_attr & USB_ENDPOINT_USAGE_MASK) == USB_ENDPOINT_USAGE_IMPLICIT_FB)
+		fmt->implicit_fb = 1;
+
+	dev_dbg(&dev->dev, "%d:%d: found sync_ep=0x%x, iface=%d, alt=%d, implicit_fb=%d\n",
+		fmt->iface, fmt->altsetting, fmt->sync_ep, fmt->sync_iface,
+		fmt->sync_altsetting, fmt->implicit_fb);
+
+	return 0;
+}
+
+static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
+{
+	int ret;
+
+	if (!subs->str_pd)
+		return 0;
+
+	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
+	if (ret < 0) {
+		dev_err(&subs->dev->dev,
+			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
+			subs->str_pd->pd_id, state, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+int snd_usb_pcm_suspend(struct snd_usb_stream *as)
+{
+	int ret;
+
+	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
+	if (ret < 0)
+		return ret;
+
+	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+int snd_usb_pcm_resume(struct snd_usb_stream *as)
+{
+	int ret;
+
+	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
+	if (ret < 0)
+		return ret;
+
+	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static void close_endpoints(struct snd_usb_audio *chip,
+			    struct snd_usb_substream *subs)
+{
+	if (subs->data_endpoint) {
+		snd_usb_endpoint_set_sync(chip, subs->data_endpoint, NULL);
+		snd_usb_endpoint_close(chip, subs->data_endpoint);
+		subs->data_endpoint = NULL;
+	}
+
+	if (subs->sync_endpoint) {
+		snd_usb_endpoint_close(chip, subs->sync_endpoint);
+		subs->sync_endpoint = NULL;
+	}
+}
+
+int snd_usb_hw_params(struct snd_usb_substream *subs,
+		      struct snd_pcm_hw_params *hw_params)
+{
+	struct snd_usb_audio *chip = subs->stream->chip;
+	const struct audioformat *fmt;
+	const struct audioformat *sync_fmt;
+	bool fixed_rate, sync_fixed_rate;
+	int ret;
+
+	ret = snd_media_start_pipeline(subs);
+	if (ret)
+		return ret;
+
+	fixed_rate = snd_usb_pcm_has_fixed_rate(subs);
+	fmt = find_substream_format(subs, hw_params);
+	if (!fmt) {
+		usb_audio_dbg(chip,
+			      "cannot find format: format=%s, rate=%d, channels=%d\n",
+			      snd_pcm_format_name(params_format(hw_params)),
+			      params_rate(hw_params), params_channels(hw_params));
+		ret = -EINVAL;
+		goto stop_pipeline;
+	}
+
+	if (fmt->implicit_fb) {
+		sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt,
+								hw_params,
+								!subs->direction,
+								&sync_fixed_rate);
+		if (!sync_fmt) {
+			usb_audio_dbg(chip,
+				      "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n",
+				      fmt->sync_ep, fmt->sync_iface,
+				      fmt->sync_altsetting,
+				      snd_pcm_format_name(params_format(hw_params)),
+				      params_rate(hw_params), params_channels(hw_params));
+			ret = -EINVAL;
+			goto stop_pipeline;
+		}
+	} else {
+		sync_fmt = fmt;
+		sync_fixed_rate = fixed_rate;
+	}
+
+	ret = snd_usb_lock_shutdown(chip);
+	if (ret < 0)
+		goto stop_pipeline;
+
+	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
+	if (ret < 0)
+		goto unlock;
+
+	if (subs->data_endpoint) {
+		if (snd_usb_endpoint_compatible(chip, subs->data_endpoint,
+						fmt, hw_params))
+			goto unlock;
+		if (stop_endpoints(subs, false))
+			sync_pending_stops(subs);
+		close_endpoints(chip, subs);
+	}
+
+	subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false, fixed_rate);
+	if (!subs->data_endpoint) {
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	if (fmt->sync_ep) {
+		subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt,
+							    hw_params,
+							    fmt == sync_fmt,
+							    sync_fixed_rate);
+		if (!subs->sync_endpoint) {
+			ret = -EINVAL;
+			goto unlock;
+		}
+
+		snd_usb_endpoint_set_sync(chip, subs->data_endpoint,
+					  subs->sync_endpoint);
+	}
+
+	scoped_guard(mutex, &chip->mutex) {
+		subs->cur_audiofmt = fmt;
+	}
+
+	if (!subs->data_endpoint->need_setup)
+		goto unlock;
+
+	if (subs->sync_endpoint) {
+		ret = snd_usb_endpoint_set_params(chip, subs->sync_endpoint);
+		if (ret < 0)
+			goto unlock;
+	}
+
+	ret = snd_usb_endpoint_set_params(chip, subs->data_endpoint);
+
+ unlock:
+	if (ret < 0)
+		close_endpoints(chip, subs);
+
+	snd_usb_unlock_shutdown(chip);
+ stop_pipeline:
+	if (ret < 0)
+		snd_media_stop_pipeline(subs);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_usb_hw_params);
+
+/*
+ * hw_params callback
+ *
+ * allocate a buffer and set the given audio format.
+ *
+ * so far we use a physically linear buffer although packetize transfer
+ * doesn't need a continuous area.
+ * if sg buffer is supported on the later version of alsa, we'll follow
+ * that.
+ */
+static int snd_usb_pcm_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *hw_params)
+{
+	struct snd_usb_substream *subs = substream->runtime->private_data;
+
+	return snd_usb_hw_params(subs, hw_params);
+}
+
+int snd_usb_hw_free(struct snd_usb_substream *subs)
+{
+	struct snd_usb_audio *chip = subs->stream->chip;
+
+	snd_media_stop_pipeline(subs);
+	scoped_guard(mutex, &chip->mutex) {
+		subs->cur_audiofmt = NULL;
+	}
+	CLASS(snd_usb_lock, pm)(chip);
+	if (!pm.err) {
+		if (stop_endpoints(subs, false))
+			sync_pending_stops(subs);
+		close_endpoints(chip, subs);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_usb_hw_free);
+
+/*
+ * hw_free callback
+ *
+ * reset the audio format and release the buffer
+ */
+static int snd_usb_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	struct snd_usb_substream *subs = substream->runtime->private_data;
+
+	return snd_usb_hw_free(subs);
+}
+
+/* free-wheeling mode? (e.g. dmix) */
+static int in_free_wheeling_mode(struct snd_pcm_runtime *runtime)
+{
+	return runtime->stop_threshold > runtime->buffer_size;
+}
+
+/* check whether early start is needed for playback stream */
+static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
+					 struct snd_usb_substream *subs)
+{
+	struct snd_usb_audio *chip = subs->stream->chip;
+
+	if (subs->direction == SNDRV_PCM_STREAM_CAPTURE)
+		return false;
+	/* disabled via module option? */
+	if (!chip->lowlatency)
+		return false;
+	if (in_free_wheeling_mode(runtime))
+		return false;
+	/* implicit feedback mode has own operation mode */
+	if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
+		return false;
+	return true;
+}
+
+/*
+ * prepare callback
+ *
+ * only a few subtle things...
+ */
+static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usb_substream *subs = runtime->private_data;
+	struct snd_usb_audio *chip = subs->stream->chip;
+	int retry = 0;
+	int ret;
+
+	CLASS(snd_usb_lock, pm)(chip);
+	if (pm.err < 0)
+		return pm.err;
+	if (snd_BUG_ON(!subs->data_endpoint))
+		return -EIO;
+
+	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
+	if (ret < 0)
+		return ret;
+
+ again:
+	if (subs->sync_endpoint) {
+		ret = snd_usb_endpoint_prepare(chip, subs->sync_endpoint);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = snd_usb_endpoint_prepare(chip, subs->data_endpoint);
+	if (ret < 0)
+		return ret;
+	else if (ret > 0)
+		snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
+	ret = 0;
+
+	/* reset the pointer */
+	subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
+	subs->inflight_bytes = 0;
+	subs->hwptr_done = 0;
+	subs->transfer_done = 0;
+	subs->last_frame_number = 0;
+	subs->period_elapsed_pending = 0;
+	runtime->delay = 0;
+
+	subs->lowlatency_playback = lowlatency_playback_available(runtime, subs);
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+	    !subs->lowlatency_playback) {
+		ret = start_endpoints(subs);
+		/* if XRUN happens at starting streams (possibly with implicit
+		 * fb case), restart again, but only try once.
+		 */
+		if (ret == -EPIPE && !retry++) {
+			sync_pending_stops(subs);
+			goto again;
+		}
+	}
+
+	return ret;
+}
+
+/*
+ * h/w constraints
+ */
+
+#ifdef HW_CONST_DEBUG
+#define hwc_debug(fmt, args...) pr_debug(fmt, ##args)
+#else
+#define hwc_debug(fmt, args...) do { } while(0)
+#endif
+
+static const struct snd_pcm_hardware snd_usb_hardware =
+{
+	.info =			SNDRV_PCM_INFO_MMAP |
+				SNDRV_PCM_INFO_MMAP_VALID |
+				SNDRV_PCM_INFO_BATCH |
+				SNDRV_PCM_INFO_INTERLEAVED |
+				SNDRV_PCM_INFO_BLOCK_TRANSFER |
+				SNDRV_PCM_INFO_PAUSE,
+	.channels_min =		1,
+	.channels_max =		256,
+	.buffer_bytes_max =	INT_MAX, /* limited by BUFFER_TIME later */
+	.period_bytes_min =	64,
+	.period_bytes_max =	INT_MAX, /* limited by PERIOD_TIME later */
+	.periods_min =		2,
+	.periods_max =		1024,
+};
+
+static int hw_check_valid_format(struct snd_usb_substream *subs,
+				 struct snd_pcm_hw_params *params,
+				 const struct audioformat *fp)
+{
+	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
+	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
+	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
+	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
+	struct snd_mask check_fmts;
+	unsigned int ptime;
+
+	/* check the format */
+	snd_mask_none(&check_fmts);
+	check_fmts.bits[0] = (u32)fp->formats;
+	check_fmts.bits[1] = (u32)(fp->formats >> 32);
+	snd_mask_intersect(&check_fmts, fmts);
+	if (snd_mask_empty(&check_fmts)) {
+		hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
+		return 0;
+	}
+	/* check the channels */
+	if (fp->channels < ct->min || fp->channels > ct->max) {
+		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
+		return 0;
+	}
+	/* check the rate is within the range */
+	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
+		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
+		return 0;
+	}
+	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
+		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
+		return 0;
+	}
+	/* check whether the period time is >= the data packet interval */
+	if (subs->speed != USB_SPEED_FULL) {
+		ptime = 125 * (1 << fp->datainterval);
+		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
+			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
+			return 0;
+		}
+	}
+	return 1;
+}
+
+static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
+				  unsigned int rmax)
+{
+	int changed;
+
+	if (rmin > rmax) {
+		hwc_debug("  --> get empty\n");
+		it->empty = 1;
+		return -EINVAL;
+	}
+
+	changed = 0;
+	if (it->min < rmin) {
+		it->min = rmin;
+		it->openmin = 0;
+		changed = 1;
+	}
+	if (it->max > rmax) {
+		it->max = rmax;
+		it->openmax = 0;
+		changed = 1;
+	}
+	if (snd_interval_checkempty(it)) {
+		it->empty = 1;
+		return -EINVAL;
+	}
+	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
+	return changed;
+}
+
+/* get the specified endpoint object that is being used by other streams
+ * (i.e. the parameter is locked)
+ */
+static const struct snd_usb_endpoint *
+get_endpoint_in_use(struct snd_usb_audio *chip, int endpoint,
+		    const struct snd_usb_endpoint *ref_ep)
+{
+	const struct snd_usb_endpoint *ep;
+
+	ep = snd_usb_get_endpoint(chip, endpoint);
+	if (ep && ep->cur_audiofmt && (ep != ref_ep || ep->opened > 1))
+		return ep;
+	return NULL;
+}
+
+static int hw_rule_rate(struct snd_pcm_hw_params *params,
+			struct snd_pcm_hw_rule *rule)
+{
+	struct snd_usb_substream *subs = rule->private;
+	struct snd_usb_audio *chip = subs->stream->chip;
+	const struct snd_usb_endpoint *ep;
+	const struct audioformat *fp;
+	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
+	unsigned int rmin, rmax, r;
+	int i;
+
+	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
+	rmin = UINT_MAX;
+	rmax = 0;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (!hw_check_valid_format(subs, params, fp))
+			continue;
+
+		ep = get_endpoint_in_use(chip, fp->endpoint,
+					 subs->data_endpoint);
+		if (ep) {
+			hwc_debug("rate limit %d for ep#%x\n",
+				  ep->cur_rate, fp->endpoint);
+			rmin = min(rmin, ep->cur_rate);
+			rmax = max(rmax, ep->cur_rate);
+			continue;
+		}
+
+		if (fp->implicit_fb) {
+			ep = get_endpoint_in_use(chip, fp->sync_ep,
+						 subs->sync_endpoint);
+			if (ep) {
+				hwc_debug("rate limit %d for sync_ep#%x\n",
+					  ep->cur_rate, fp->sync_ep);
+				rmin = min(rmin, ep->cur_rate);
+				rmax = max(rmax, ep->cur_rate);
+				continue;
+			}
+		}
+
+		r = snd_usb_endpoint_get_clock_rate(chip, fp->clock);
+		if (r > 0) {
+			if (!snd_interval_test(it, r))
+				continue;
+			rmin = min(rmin, r);
+			rmax = max(rmax, r);
+			continue;
+		}
+		if (fp->rate_table && fp->nr_rates) {
+			for (i = 0; i < fp->nr_rates; i++) {
+				r = fp->rate_table[i];
+				if (!snd_interval_test(it, r))
+					continue;
+				rmin = min(rmin, r);
+				rmax = max(rmax, r);
+			}
+		} else {
+			rmin = min(rmin, fp->rate_min);
+			rmax = max(rmax, fp->rate_max);
+		}
+	}
+
+	return apply_hw_params_minmax(it, rmin, rmax);
+}
+
+
+static int hw_rule_channels(struct snd_pcm_hw_params *params,
+			    struct snd_pcm_hw_rule *rule)
+{
+	struct snd_usb_substream *subs = rule->private;
+	const struct audioformat *fp;
+	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
+	unsigned int rmin, rmax;
+
+	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
+	rmin = UINT_MAX;
+	rmax = 0;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (!hw_check_valid_format(subs, params, fp))
+			continue;
+		rmin = min(rmin, fp->channels);
+		rmax = max(rmax, fp->channels);
+	}
+
+	return apply_hw_params_minmax(it, rmin, rmax);
+}
+
+static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
+{
+	u32 oldbits[2];
+	int changed;
+
+	oldbits[0] = fmt->bits[0];
+	oldbits[1] = fmt->bits[1];
+	fmt->bits[0] &= (u32)fbits;
+	fmt->bits[1] &= (u32)(fbits >> 32);
+	if (!fmt->bits[0] && !fmt->bits[1]) {
+		hwc_debug("  --> get empty\n");
+		return -EINVAL;
+	}
+	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
+	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
+	return changed;
+}
+
+static int hw_rule_format(struct snd_pcm_hw_params *params,
+			  struct snd_pcm_hw_rule *rule)
+{
+	struct snd_usb_substream *subs = rule->private;
+	struct snd_usb_audio *chip = subs->stream->chip;
+	const struct snd_usb_endpoint *ep;
+	const struct audioformat *fp;
+	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
+	u64 fbits;
+
+	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
+	fbits = 0;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (!hw_check_valid_format(subs, params, fp))
+			continue;
+
+		ep = get_endpoint_in_use(chip, fp->endpoint,
+					 subs->data_endpoint);
+		if (ep) {
+			hwc_debug("format limit %d for ep#%x\n",
+				  ep->cur_format, fp->endpoint);
+			fbits |= pcm_format_to_bits(ep->cur_format);
+			continue;
+		}
+
+		if (fp->implicit_fb) {
+			ep = get_endpoint_in_use(chip, fp->sync_ep,
+						 subs->sync_endpoint);
+			if (ep) {
+				hwc_debug("format limit %d for sync_ep#%x\n",
+					  ep->cur_format, fp->sync_ep);
+				fbits |= pcm_format_to_bits(ep->cur_format);
+				continue;
+			}
+		}
+
+		fbits |= fp->formats;
+	}
+	return apply_hw_params_format_bits(fmt, fbits);
+}
+
+static int hw_rule_period_time(struct snd_pcm_hw_params *params,
+			       struct snd_pcm_hw_rule *rule)
+{
+	struct snd_usb_substream *subs = rule->private;
+	const struct audioformat *fp;
+	struct snd_interval *it;
+	unsigned char min_datainterval;
+	unsigned int pmin;
+
+	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
+	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
+	min_datainterval = 0xff;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (!hw_check_valid_format(subs, params, fp))
+			continue;
+		min_datainterval = min(min_datainterval, fp->datainterval);
+	}
+	if (min_datainterval == 0xff) {
+		hwc_debug("  --> get empty\n");
+		it->empty = 1;
+		return -EINVAL;
+	}
+	pmin = 125 * (1 << min_datainterval);
+
+	return apply_hw_params_minmax(it, pmin, UINT_MAX);
+}
+
+/* additional hw constraints for implicit feedback mode */
+static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
+					   struct snd_pcm_hw_rule *rule)
+{
+	struct snd_usb_substream *subs = rule->private;
+	struct snd_usb_audio *chip = subs->stream->chip;
+	const struct audioformat *fp;
+	const struct snd_usb_endpoint *ep;
+	struct snd_interval *it;
+	unsigned int rmin, rmax;
+
+	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
+	hwc_debug("hw_rule_period_size: (%u,%u)\n", it->min, it->max);
+	rmin = UINT_MAX;
+	rmax = 0;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (!hw_check_valid_format(subs, params, fp))
+			continue;
+		ep = get_endpoint_in_use(chip, fp->endpoint,
+					 subs->data_endpoint);
+		if (ep) {
+			hwc_debug("period size limit %d for ep#%x\n",
+				  ep->cur_period_frames, fp->endpoint);
+			rmin = min(rmin, ep->cur_period_frames);
+			rmax = max(rmax, ep->cur_period_frames);
+			continue;
+		}
+
+		if (fp->implicit_fb) {
+			ep = get_endpoint_in_use(chip, fp->sync_ep,
+						 subs->sync_endpoint);
+			if (ep) {
+				hwc_debug("period size limit %d for sync_ep#%x\n",
+					  ep->cur_period_frames, fp->sync_ep);
+				rmin = min(rmin, ep->cur_period_frames);
+				rmax = max(rmax, ep->cur_period_frames);
+				continue;
+			}
+		}
+	}
+
+	if (!rmax)
+		return 0; /* no limit by implicit fb */
+	return apply_hw_params_minmax(it, rmin, rmax);
+}
+
+static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
+				       struct snd_pcm_hw_rule *rule)
+{
+	struct snd_usb_substream *subs = rule->private;
+	struct snd_usb_audio *chip = subs->stream->chip;
+	const struct audioformat *fp;
+	const struct snd_usb_endpoint *ep;
+	struct snd_interval *it;
+	unsigned int rmin, rmax;
+
+	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
+	hwc_debug("hw_rule_periods: (%u,%u)\n", it->min, it->max);
+	rmin = UINT_MAX;
+	rmax = 0;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (!hw_check_valid_format(subs, params, fp))
+			continue;
+		ep = get_endpoint_in_use(chip, fp->endpoint,
+					 subs->data_endpoint);
+		if (ep) {
+			hwc_debug("periods limit %d for ep#%x\n",
+				  ep->cur_buffer_periods, fp->endpoint);
+			rmin = min(rmin, ep->cur_buffer_periods);
+			rmax = max(rmax, ep->cur_buffer_periods);
+			continue;
+		}
+
+		if (fp->implicit_fb) {
+			ep = get_endpoint_in_use(chip, fp->sync_ep,
+						 subs->sync_endpoint);
+			if (ep) {
+				hwc_debug("periods limit %d for sync_ep#%x\n",
+					  ep->cur_buffer_periods, fp->sync_ep);
+				rmin = min(rmin, ep->cur_buffer_periods);
+				rmax = max(rmax, ep->cur_buffer_periods);
+				continue;
+			}
+		}
+	}
+
+	if (!rmax)
+		return 0; /* no limit by implicit fb */
+	return apply_hw_params_minmax(it, rmin, rmax);
+}
+
+/*
+ * set up the runtime hardware information.
+ */
+
+static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
+{
+	const struct audioformat *fp;
+	unsigned int pt, ptmin;
+	int param_period_time_if_needed = -1;
+	int err;
+
+	runtime->hw.formats = subs->formats;
+
+	runtime->hw.rate_min = 0x7fffffff;
+	runtime->hw.rate_max = 0;
+	runtime->hw.channels_min = 256;
+	runtime->hw.channels_max = 0;
+	runtime->hw.rates = 0;
+	ptmin = UINT_MAX;
+	/* check min/max rates and channels */
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		runtime->hw.rates |= fp->rates;
+		if (runtime->hw.rate_min > fp->rate_min)
+			runtime->hw.rate_min = fp->rate_min;
+		if (runtime->hw.rate_max < fp->rate_max)
+			runtime->hw.rate_max = fp->rate_max;
+		if (runtime->hw.channels_min > fp->channels)
+			runtime->hw.channels_min = fp->channels;
+		if (runtime->hw.channels_max < fp->channels)
+			runtime->hw.channels_max = fp->channels;
+		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
+			/* FIXME: there might be more than one audio formats... */
+			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
+				fp->frame_size;
+		}
+		pt = 125 * (1 << fp->datainterval);
+		ptmin = min(ptmin, pt);
+	}
+
+	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
+	if (subs->speed == USB_SPEED_FULL)
+		/* full speed devices have fixed data packet interval */
+		ptmin = 1000;
+	if (ptmin == 1000)
+		/* if period time doesn't go below 1 ms, no rules needed */
+		param_period_time_if_needed = -1;
+
+	err = snd_pcm_hw_constraint_minmax(runtime,
+					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
+					   ptmin, UINT_MAX);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
+				  hw_rule_rate, subs,
+				  SNDRV_PCM_HW_PARAM_RATE,
+				  SNDRV_PCM_HW_PARAM_FORMAT,
+				  SNDRV_PCM_HW_PARAM_CHANNELS,
+				  param_period_time_if_needed,
+				  -1);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
+				  hw_rule_channels, subs,
+				  SNDRV_PCM_HW_PARAM_CHANNELS,
+				  SNDRV_PCM_HW_PARAM_FORMAT,
+				  SNDRV_PCM_HW_PARAM_RATE,
+				  param_period_time_if_needed,
+				  -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
+				  hw_rule_format, subs,
+				  SNDRV_PCM_HW_PARAM_FORMAT,
+				  SNDRV_PCM_HW_PARAM_RATE,
+				  SNDRV_PCM_HW_PARAM_CHANNELS,
+				  param_period_time_if_needed,
+				  -1);
+	if (err < 0)
+		return err;
+	if (param_period_time_if_needed >= 0) {
+		err = snd_pcm_hw_rule_add(runtime, 0,
+					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
+					  hw_rule_period_time, subs,
+					  SNDRV_PCM_HW_PARAM_FORMAT,
+					  SNDRV_PCM_HW_PARAM_CHANNELS,
+					  SNDRV_PCM_HW_PARAM_RATE,
+					  -1);
+		if (err < 0)
+			return err;
+	}
+
+	/* set max period and buffer sizes for 1 and 2 seconds, respectively */
+	err = snd_pcm_hw_constraint_minmax(runtime,
+					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
+					   0, 1000000);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_constraint_minmax(runtime,
+					   SNDRV_PCM_HW_PARAM_BUFFER_TIME,
+					   0, 2000000);
+	if (err < 0)
+		return err;
+
+	/* additional hw constraints for implicit fb */
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
+				  hw_rule_period_size_implicit_fb, subs,
+				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
+				  hw_rule_periods_implicit_fb, subs,
+				  SNDRV_PCM_HW_PARAM_PERIODS, -1);
+	if (err < 0)
+		return err;
+
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		if (fp->implicit_fb) {
+			runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
+{
+	int direction = substream->stream;
+	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usb_substream *subs = &as->substream[direction];
+	struct snd_usb_audio *chip = subs->stream->chip;
+	int ret;
+
+	scoped_guard(mutex, &chip->mutex) {
+		if (subs->opened)
+			return -EBUSY;
+		subs->opened = 1;
+	}
+
+	runtime->hw = snd_usb_hardware;
+	/* need an explicit sync to catch applptr update in low-latency mode */
+	if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
+	    as->chip->lowlatency)
+		runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR;
+	runtime->private_data = subs;
+	subs->pcm_substream = substream;
+	/* runtime PM is also done there */
+
+	/* initialize DSD/DOP context */
+	subs->dsd_dop.byte_idx = 0;
+	subs->dsd_dop.channel = 0;
+	subs->dsd_dop.marker = 1;
+
+	ret = setup_hw_info(runtime, subs);
+	if (ret < 0)
+		goto err_open;
+	ret = snd_usb_autoresume(subs->stream->chip);
+	if (ret < 0)
+		goto err_open;
+	ret = snd_media_stream_init(subs, as->pcm, direction);
+	if (ret < 0)
+		goto err_resume;
+
+	return 0;
+
+err_resume:
+	snd_usb_autosuspend(subs->stream->chip);
+err_open:
+	scoped_guard(mutex, &chip->mutex) {
+		subs->opened = 0;
+	}
+
+	return ret;
+}
+
+static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
+{
+	int direction = substream->stream;
+	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
+	struct snd_usb_substream *subs = &as->substream[direction];
+	struct snd_usb_audio *chip = subs->stream->chip;
+	int ret;
+
+	snd_media_stop_pipeline(subs);
+
+	{
+		CLASS(snd_usb_lock, pm)(subs->stream->chip);
+		if (pm.err)
+			return pm.err;
+		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
+		if (ret < 0)
+			return ret;
+	}
+
+	subs->pcm_substream = NULL;
+	snd_usb_autosuspend(subs->stream->chip);
+	scoped_guard(mutex, &chip->mutex) {
+		subs->opened = 0;
+	}
+
+	return 0;
+}
+
+/* Since a URB can handle only a single linear buffer, we must use double
+ * buffering when the data to be transferred overflows the buffer boundary.
+ * To avoid inconsistencies when updating hwptr_done, we use double buffering
+ * for all URBs.
+ */
+static void retire_capture_urb(struct snd_usb_substream *subs,
+			       struct urb *urb)
+{
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+	unsigned int stride, frames, bytes, oldptr;
+	int i, period_elapsed = 0;
+	unsigned char *cp;
+	int current_frame_number;
+
+	/* read frame number here, update pointer in critical section */
+	current_frame_number = usb_get_current_frame_number(subs->dev);
+
+	stride = runtime->frame_bits >> 3;
+
+	for (i = 0; i < urb->number_of_packets; i++) {
+		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
+		if (urb->iso_frame_desc[i].status)
+			dev_dbg_ratelimited(&subs->dev->dev,
+					    "frame %d active: %d\n", i,
+					    urb->iso_frame_desc[i].status);
+		bytes = urb->iso_frame_desc[i].actual_length;
+		if (subs->stream_offset_adj > 0) {
+			unsigned int adj = min(subs->stream_offset_adj, bytes);
+			cp += adj;
+			bytes -= adj;
+			subs->stream_offset_adj -= adj;
+		}
+		frames = bytes / stride;
+		if (!subs->txfr_quirk)
+			bytes = frames * stride;
+		if (bytes % (runtime->sample_bits >> 3) != 0) {
+			int oldbytes = bytes;
+			bytes = frames * stride;
+			dev_warn_ratelimited(&subs->dev->dev,
+				 "Corrected urb data len. %d->%d\n",
+							oldbytes, bytes);
+		}
+		/* update the current pointer */
+		scoped_guard(spinlock_irqsave, &subs->lock) {
+			oldptr = subs->hwptr_done;
+			subs->hwptr_done += bytes;
+			if (subs->hwptr_done >= subs->buffer_bytes)
+				subs->hwptr_done -= subs->buffer_bytes;
+			frames = (bytes + (oldptr % stride)) / stride;
+			subs->transfer_done += frames;
+			if (subs->transfer_done >= runtime->period_size) {
+				subs->transfer_done -= runtime->period_size;
+				period_elapsed = 1;
+			}
+
+			/* realign last_frame_number */
+			subs->last_frame_number = current_frame_number;
+		}
+		/* copy a data chunk */
+		if (oldptr + bytes > subs->buffer_bytes) {
+			unsigned int bytes1 = subs->buffer_bytes - oldptr;
+
+			memcpy(runtime->dma_area + oldptr, cp, bytes1);
+			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
+		} else {
+			memcpy(runtime->dma_area + oldptr, cp, bytes);
+		}
+	}
+
+	if (period_elapsed)
+		snd_pcm_period_elapsed(subs->pcm_substream);
+}
+
+static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
+				  struct urb *urb, unsigned int bytes)
+{
+	struct snd_urb_ctx *ctx = urb->context;
+
+	ctx->queued += bytes;
+	subs->inflight_bytes += bytes;
+	subs->hwptr_done += bytes;
+	if (subs->hwptr_done >= subs->buffer_bytes)
+		subs->hwptr_done -= subs->buffer_bytes;
+}
+
+static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
+					     struct urb *urb, unsigned int bytes)
+{
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+	unsigned int dst_idx = 0;
+	unsigned int src_idx = subs->hwptr_done;
+	unsigned int wrap = subs->buffer_bytes;
+	u8 *dst = urb->transfer_buffer;
+	u8 *src = runtime->dma_area;
+	static const u8 marker[] = { 0x05, 0xfa };
+	unsigned int queued = 0;
+
+	/*
+	 * The DSP DOP format defines a way to transport DSD samples over
+	 * normal PCM data endpoints. It requires stuffing of marker bytes
+	 * (0x05 and 0xfa, alternating per sample frame), and then expects
+	 * 2 additional bytes of actual payload. The whole frame is stored
+	 * LSB.
+	 *
+	 * Hence, for a stereo transport, the buffer layout looks like this,
+	 * where L refers to left channel samples and R to right.
+	 *
+	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
+	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
+	 *   .....
+	 *
+	 */
+
+	while (bytes--) {
+		if (++subs->dsd_dop.byte_idx == 3) {
+			/* frame boundary? */
+			dst[dst_idx++] = marker[subs->dsd_dop.marker];
+			src_idx += 2;
+			subs->dsd_dop.byte_idx = 0;
+
+			if (++subs->dsd_dop.channel % runtime->channels == 0) {
+				/* alternate the marker */
+				subs->dsd_dop.marker++;
+				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
+				subs->dsd_dop.channel = 0;
+			}
+		} else {
+			/* stuff the DSD payload */
+			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
+
+			if (subs->cur_audiofmt->dsd_bitrev)
+				dst[dst_idx++] = bitrev8(src[idx]);
+			else
+				dst[dst_idx++] = src[idx];
+			queued++;
+		}
+	}
+
+	urb_ctx_queue_advance(subs, urb, queued);
+}
+
+/* copy bit-reversed bytes onto transfer buffer */
+static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
+					 struct urb *urb, unsigned int bytes)
+{
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+	const u8 *src = runtime->dma_area;
+	u8 *buf = urb->transfer_buffer;
+	int i, ofs = subs->hwptr_done;
+
+	for (i = 0; i < bytes; i++) {
+		*buf++ = bitrev8(src[ofs]);
+		if (++ofs >= subs->buffer_bytes)
+			ofs = 0;
+	}
+
+	urb_ctx_queue_advance(subs, urb, bytes);
+}
+
+static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
+			int offset, int stride, unsigned int bytes)
+{
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+
+	if (subs->hwptr_done + bytes > subs->buffer_bytes) {
+		/* err, the transferred area goes over buffer boundary. */
+		unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
+
+		memcpy(urb->transfer_buffer + offset,
+		       runtime->dma_area + subs->hwptr_done, bytes1);
+		memcpy(urb->transfer_buffer + offset + bytes1,
+		       runtime->dma_area, bytes - bytes1);
+	} else {
+		memcpy(urb->transfer_buffer + offset,
+		       runtime->dma_area + subs->hwptr_done, bytes);
+	}
+
+	urb_ctx_queue_advance(subs, urb, bytes);
+}
+
+static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
+				      struct urb *urb, int stride,
+				      unsigned int bytes)
+{
+	__le32 packet_length;
+	int i;
+
+	/* Put __le32 length descriptor at start of each packet. */
+	for (i = 0; i < urb->number_of_packets; i++) {
+		unsigned int length = urb->iso_frame_desc[i].length;
+		unsigned int offset = urb->iso_frame_desc[i].offset;
+
+		packet_length = cpu_to_le32(length);
+		offset += i * sizeof(packet_length);
+		urb->iso_frame_desc[i].offset = offset;
+		urb->iso_frame_desc[i].length += sizeof(packet_length);
+		memcpy(urb->transfer_buffer + offset,
+		       &packet_length, sizeof(packet_length));
+		copy_to_urb(subs, urb, offset + sizeof(packet_length),
+			    stride, length);
+	}
+	/* Adjust transfer size accordingly. */
+	bytes += urb->number_of_packets * sizeof(packet_length);
+	return bytes;
+}
+
+static int prepare_playback_urb(struct snd_usb_substream *subs,
+				struct urb *urb,
+				bool in_stream_lock)
+{
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+	struct snd_usb_endpoint *ep = subs->data_endpoint;
+	struct snd_urb_ctx *ctx = urb->context;
+	unsigned int frames, bytes;
+	int counts;
+	unsigned int transfer_done, frame_limit, avail = 0;
+	int i, stride, period_elapsed = 0;
+
+	stride = ep->stride;
+
+	frames = 0;
+	ctx->queued = 0;
+	urb->number_of_packets = 0;
+
+	scoped_guard(spinlock_irqsave, &subs->lock) {
+		frame_limit = subs->frame_limit + ep->max_urb_frames;
+		transfer_done = subs->transfer_done;
+
+		if (subs->lowlatency_playback &&
+		    runtime->state != SNDRV_PCM_STATE_DRAINING) {
+			unsigned int hwptr = subs->hwptr_done / stride;
+
+			/* calculate the byte offset-in-buffer of the appl_ptr */
+			avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
+				% runtime->buffer_size;
+			if (avail <= hwptr)
+				avail += runtime->buffer_size;
+			avail -= hwptr;
+		}
+
+		for (i = 0; i < ctx->packets; i++) {
+			counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
+			if (counts < 0 ||
+			    (frames + counts) * stride > ctx->buffer_size)
+				break;
+			/* set up descriptor */
+			urb->iso_frame_desc[i].offset = frames * stride;
+			urb->iso_frame_desc[i].length = counts * stride;
+			frames += counts;
+			avail -= counts;
+			urb->number_of_packets++;
+			transfer_done += counts;
+			if (transfer_done >= runtime->period_size) {
+				transfer_done -= runtime->period_size;
+				frame_limit = 0;
+				period_elapsed = 1;
+				if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
+					if (transfer_done > 0) {
+						/* FIXME: fill-max mode is not
+						 * supported yet */
+						frames -= transfer_done;
+						counts -= transfer_done;
+						urb->iso_frame_desc[i].length =
+							counts * stride;
+						transfer_done = 0;
+					}
+					i++;
+					if (i < ctx->packets) {
+						/* add a transfer delimiter */
+						urb->iso_frame_desc[i].offset =
+							frames * stride;
+						urb->iso_frame_desc[i].length = 0;
+						urb->number_of_packets++;
+					}
+					break;
+				}
+			}
+			/* finish at the period boundary or after enough frames */
+			if ((period_elapsed || transfer_done >= frame_limit) &&
+			    !snd_usb_endpoint_implicit_feedback_sink(ep))
+				break;
+		}
+
+		if (!frames)
+			return -EAGAIN;
+
+		bytes = frames * stride;
+		subs->transfer_done = transfer_done;
+		subs->frame_limit = frame_limit;
+		if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
+			     subs->cur_audiofmt->dsd_dop)) {
+			fill_playback_urb_dsd_dop(subs, urb, bytes);
+		} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
+				    subs->cur_audiofmt->dsd_bitrev)) {
+			fill_playback_urb_dsd_bitrev(subs, urb, bytes);
+		} else {
+			/* usual PCM */
+			if (!subs->tx_length_quirk)
+				copy_to_urb(subs, urb, 0, stride, bytes);
+			else
+				bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
+			/* bytes is now amount of outgoing data */
+		}
+
+		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
+
+		if (subs->trigger_tstamp_pending_update) {
+			/* this is the first actual URB submitted,
+			 * update trigger timestamp to reflect actual start time
+			 */
+			snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
+			subs->trigger_tstamp_pending_update = false;
+		}
+
+		if (period_elapsed && !subs->running && subs->lowlatency_playback) {
+			subs->period_elapsed_pending = 1;
+			period_elapsed = 0;
+		}
+	}
+
+	urb->transfer_buffer_length = bytes;
+	if (period_elapsed) {
+		if (in_stream_lock)
+			snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
+		else
+			snd_pcm_period_elapsed(subs->pcm_substream);
+	}
+	return 0;
+}
+
+/*
+ * process after playback data complete
+ * - decrease the delay count again
+ */
+static void retire_playback_urb(struct snd_usb_substream *subs,
+			       struct urb *urb)
+{
+	struct snd_urb_ctx *ctx = urb->context;
+	bool period_elapsed = false;
+
+	scoped_guard(spinlock_irqsave, &subs->lock) {
+		if (ctx->queued) {
+			if (subs->inflight_bytes >= ctx->queued)
+				subs->inflight_bytes -= ctx->queued;
+			else
+				subs->inflight_bytes = 0;
+		}
+
+		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
+		if (subs->running) {
+			period_elapsed = subs->period_elapsed_pending;
+			subs->period_elapsed_pending = 0;
+		}
+	}
+	if (period_elapsed)
+		snd_pcm_period_elapsed(subs->pcm_substream);
+}
+
+/* PCM ack callback for the playback stream;
+ * this plays a role only when the stream is running in low-latency mode.
+ */
+static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
+{
+	struct snd_usb_substream *subs = substream->runtime->private_data;
+	struct snd_usb_endpoint *ep;
+
+	if (!subs->lowlatency_playback || !subs->running)
+		return 0;
+	ep = subs->data_endpoint;
+	if (!ep)
+		return 0;
+	/* When no more in-flight URBs available, try to process the pending
+	 * outputs here
+	 */
+	if (!ep->active_mask)
+		return snd_usb_queue_pending_output_urbs(ep, true);
+	return 0;
+}
+
+static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
+					      int cmd)
+{
+	struct snd_usb_substream *subs = substream->runtime->private_data;
+	int err;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		subs->trigger_tstamp_pending_update = true;
+		fallthrough;
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		snd_usb_endpoint_set_callback(subs->data_endpoint,
+					      prepare_playback_urb,
+					      retire_playback_urb,
+					      subs);
+		if (subs->lowlatency_playback &&
+		    cmd == SNDRV_PCM_TRIGGER_START) {
+			if (in_free_wheeling_mode(substream->runtime))
+				subs->lowlatency_playback = false;
+			err = start_endpoints(subs);
+			if (err < 0) {
+				snd_usb_endpoint_set_callback(subs->data_endpoint,
+							      NULL, NULL, NULL);
+				return err;
+			}
+		}
+		subs->running = 1;
+		dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
+			subs->cur_audiofmt->iface,
+			subs->cur_audiofmt->altsetting);
+		return 0;
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_STOP:
+		stop_endpoints(subs, substream->runtime->state == SNDRV_PCM_STATE_DRAINING);
+		snd_usb_endpoint_set_callback(subs->data_endpoint,
+					      NULL, NULL, NULL);
+		subs->running = 0;
+		dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
+			subs->cur_audiofmt->iface,
+			subs->cur_audiofmt->altsetting);
+		return 0;
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		/* keep retire_data_urb for delay calculation */
+		snd_usb_endpoint_set_callback(subs->data_endpoint,
+					      NULL,
+					      retire_playback_urb,
+					      subs);
+		subs->running = 0;
+		dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
+			subs->cur_audiofmt->iface,
+			subs->cur_audiofmt->altsetting);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
+					     int cmd)
+{
+	int err;
+	struct snd_usb_substream *subs = substream->runtime->private_data;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		err = start_endpoints(subs);
+		if (err < 0)
+			return err;
+		fallthrough;
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		snd_usb_endpoint_set_callback(subs->data_endpoint,
+					      NULL, retire_capture_urb,
+					      subs);
+		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
+		subs->running = 1;
+		dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
+			subs->cur_audiofmt->iface,
+			subs->cur_audiofmt->altsetting);
+		return 0;
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_STOP:
+		stop_endpoints(subs, false);
+		fallthrough;
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		snd_usb_endpoint_set_callback(subs->data_endpoint,
+					      NULL, NULL, NULL);
+		subs->running = 0;
+		dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
+			subs->cur_audiofmt->iface,
+			subs->cur_audiofmt->altsetting);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static const struct snd_pcm_ops snd_usb_playback_ops = {
+	.open =		snd_usb_pcm_open,
+	.close =	snd_usb_pcm_close,
+	.hw_params =	snd_usb_pcm_hw_params,
+	.hw_free =	snd_usb_pcm_hw_free,
+	.prepare =	snd_usb_pcm_prepare,
+	.trigger =	snd_usb_substream_playback_trigger,
+	.sync_stop =	snd_usb_pcm_sync_stop,
+	.pointer =	snd_usb_pcm_pointer,
+	.ack =		snd_usb_pcm_playback_ack,
+};
+
+static const struct snd_pcm_ops snd_usb_capture_ops = {
+	.open =		snd_usb_pcm_open,
+	.close =	snd_usb_pcm_close,
+	.hw_params =	snd_usb_pcm_hw_params,
+	.hw_free =	snd_usb_pcm_hw_free,
+	.prepare =	snd_usb_pcm_prepare,
+	.trigger =	snd_usb_substream_capture_trigger,
+	.sync_stop =	snd_usb_pcm_sync_stop,
+	.pointer =	snd_usb_pcm_pointer,
+};
+
+void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
+{
+	const struct snd_pcm_ops *ops;
+
+	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
+			&snd_usb_playback_ops : &snd_usb_capture_ops;
+	snd_pcm_set_ops(pcm, stream, ops);
+}
+
+void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
+{
+	struct snd_pcm *pcm = subs->stream->pcm;
+	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
+	struct device *dev = subs->dev->bus->sysdev;
+
+	if (snd_usb_use_vmalloc)
+		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
+					   NULL, 0, 0);
+	else
+		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
+					   dev, 64*1024, 512*1024);
+}
diff --git a/sound/usb/pcm.h b/sound/usb/pcm.h
new file mode 100644
index 000000000..c096021ad
--- /dev/null
+++ b/sound/usb/pcm.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_PCM_H
+#define __USBAUDIO_PCM_H
+
+void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream);
+int snd_usb_pcm_suspend(struct snd_usb_stream *as);
+int snd_usb_pcm_resume(struct snd_usb_stream *as);
+
+bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *as);
+
+int snd_usb_init_pitch(struct snd_usb_audio *chip,
+		       const struct audioformat *fmt);
+void snd_usb_preallocate_buffer(struct snd_usb_substream *subs);
+
+int snd_usb_audioformat_set_sync_ep(struct snd_usb_audio *chip,
+				    struct audioformat *fmt);
+
+const struct audioformat *
+snd_usb_find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,
+		    unsigned int rate, unsigned int channels, bool strict_match,
+		    struct snd_usb_substream *subs);
+const struct audioformat *
+snd_usb_find_substream_format(struct snd_usb_substream *subs,
+			      const struct snd_pcm_hw_params *params);
+
+int snd_usb_hw_params(struct snd_usb_substream *subs,
+		      struct snd_pcm_hw_params *hw_params);
+int snd_usb_hw_free(struct snd_usb_substream *subs);
+#endif /* __USBAUDIO_PCM_H */
diff --git a/sound/usb/power.c b/sound/usb/power.c
new file mode 100644
index 000000000..c2d708c87
--- /dev/null
+++ b/sound/usb/power.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *   UAC3 Power Domain state management functions
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+
+#include "usbaudio.h"
+#include "helper.h"
+#include "power.h"
+
+struct snd_usb_power_domain *
+snd_usb_find_power_domain(struct usb_host_interface *ctrl_iface,
+			  unsigned char id)
+{
+	struct snd_usb_power_domain *pd;
+	void *p;
+
+	pd = kzalloc_obj(*pd);
+	if (!pd)
+		return NULL;
+
+	p = NULL;
+	while ((p = snd_usb_find_csint_desc(ctrl_iface->extra,
+					    ctrl_iface->extralen,
+					    p, UAC3_POWER_DOMAIN)) != NULL) {
+		struct uac3_power_domain_descriptor *pd_desc = p;
+		int i;
+
+		if (!snd_usb_validate_audio_desc(p, UAC_VERSION_3))
+			continue;
+		for (i = 0; i < pd_desc->bNrEntities; i++) {
+			if (pd_desc->baEntityID[i] == id) {
+				pd->pd_id = pd_desc->bPowerDomainID;
+				pd->pd_d1d0_rec =
+					le16_to_cpu(pd_desc->waRecoveryTime1);
+				pd->pd_d2d0_rec =
+					le16_to_cpu(pd_desc->waRecoveryTime2);
+				pd->ctrl_iface = ctrl_iface;
+				return pd;
+			}
+		}
+	}
+
+	kfree(pd);
+	return NULL;
+}
+
+int snd_usb_power_domain_set(struct snd_usb_audio *chip,
+			     struct snd_usb_power_domain *pd,
+			     unsigned char state)
+{
+	struct usb_device *dev = chip->dev;
+	unsigned char current_state;
+	int err, idx;
+
+	idx = snd_usb_ctrl_intf(pd->ctrl_iface) | (pd->pd_id << 8);
+
+	err = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
+			      UAC2_CS_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			      UAC3_AC_POWER_DOMAIN_CONTROL << 8, idx,
+			      &current_state, sizeof(current_state));
+	if (err < 0) {
+		dev_err(&dev->dev, "Can't get UAC3 power state for id %d\n",
+			pd->pd_id);
+		return err;
+	}
+
+	if (current_state == state) {
+		dev_dbg(&dev->dev, "UAC3 power domain id %d already in state %d\n",
+			pd->pd_id, state);
+		return 0;
+	}
+
+	err = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC2_CS_CUR,
+			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			      UAC3_AC_POWER_DOMAIN_CONTROL << 8, idx,
+			      &state, sizeof(state));
+	if (err < 0) {
+		dev_err(&dev->dev, "Can't set UAC3 power state to %d for id %d\n",
+			state, pd->pd_id);
+		return err;
+	}
+
+	if (state == UAC3_PD_STATE_D0) {
+		switch (current_state) {
+		case UAC3_PD_STATE_D2:
+			udelay(pd->pd_d2d0_rec * 50);
+			break;
+		case UAC3_PD_STATE_D1:
+			udelay(pd->pd_d1d0_rec * 50);
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	dev_dbg(&dev->dev, "UAC3 power domain id %d change to state %d\n",
+		pd->pd_id, state);
+
+	return 0;
+}
diff --git a/sound/usb/power.h b/sound/usb/power.h
new file mode 100644
index 000000000..1fa92ad0c
--- /dev/null
+++ b/sound/usb/power.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_POWER_H
+#define __USBAUDIO_POWER_H
+
+struct snd_usb_power_domain {
+	int pd_id;              /* UAC3 Power Domain ID */
+	int pd_d1d0_rec;        /* D1 to D0 recovery time */
+	int pd_d2d0_rec;        /* D2 to D0 recovery time */
+	struct usb_host_interface *ctrl_iface; /* Control interface */
+};
+
+enum {
+	UAC3_PD_STATE_D0,
+	UAC3_PD_STATE_D1,
+	UAC3_PD_STATE_D2,
+};
+
+int snd_usb_power_domain_set(struct snd_usb_audio *chip,
+			     struct snd_usb_power_domain *pd,
+			     unsigned char state);
+struct snd_usb_power_domain *
+snd_usb_find_power_domain(struct usb_host_interface *ctrl_iface,
+			  unsigned char id);
+
+int snd_usb_autoresume(struct snd_usb_audio *chip);
+void snd_usb_autosuspend(struct snd_usb_audio *chip);
+
+#endif /* __USBAUDIO_POWER_H */
diff --git a/sound/usb/proc.c b/sound/usb/proc.c
new file mode 100644
index 000000000..f4b7a7ff3
--- /dev/null
+++ b/sound/usb/proc.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+#include <linux/init.h>
+#include <linux/usb.h>
+
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+
+#include "usbaudio.h"
+#include "helper.h"
+#include "card.h"
+#include "endpoint.h"
+#include "proc.h"
+
+/* convert our full speed USB rate into sampling rate in Hz */
+static inline unsigned get_full_speed_hz(unsigned int usb_rate)
+{
+	return (usb_rate * 125 + (1 << 12)) >> 13;
+}
+
+/* convert our high speed USB rate into sampling rate in Hz */
+static inline unsigned get_high_speed_hz(unsigned int usb_rate)
+{
+	return (usb_rate * 125 + (1 << 9)) >> 10;
+}
+
+/*
+ * common proc files to show the usb device info
+ */
+static void proc_audio_usbbus_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
+{
+	struct snd_usb_audio *chip = entry->private_data;
+	if (!atomic_read(&chip->shutdown))
+		snd_iprintf(buffer, "%03d/%03d\n", chip->dev->bus->busnum, chip->dev->devnum);
+}
+
+static void proc_audio_usbid_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
+{
+	struct snd_usb_audio *chip = entry->private_data;
+	if (!atomic_read(&chip->shutdown))
+		snd_iprintf(buffer, "%04x:%04x\n", 
+			    USB_ID_VENDOR(chip->usb_id),
+			    USB_ID_PRODUCT(chip->usb_id));
+}
+
+void snd_usb_audio_create_proc(struct snd_usb_audio *chip)
+{
+	snd_card_ro_proc_new(chip->card, "usbbus", chip,
+			     proc_audio_usbbus_read);
+	snd_card_ro_proc_new(chip->card, "usbid", chip,
+			     proc_audio_usbid_read);
+}
+
+static const char * const channel_labels[] = {
+	[SNDRV_CHMAP_NA]	= "N/A",
+	[SNDRV_CHMAP_MONO]	= "MONO",
+	[SNDRV_CHMAP_FL]	= "FL",
+	[SNDRV_CHMAP_FR]	= "FR",
+	[SNDRV_CHMAP_FC]	= "FC",
+	[SNDRV_CHMAP_LFE]	= "LFE",
+	[SNDRV_CHMAP_RL]	= "RL",
+	[SNDRV_CHMAP_RR]	= "RR",
+	[SNDRV_CHMAP_FLC]	= "FLC",
+	[SNDRV_CHMAP_FRC]	= "FRC",
+	[SNDRV_CHMAP_RC]	= "RC",
+	[SNDRV_CHMAP_SL]	= "SL",
+	[SNDRV_CHMAP_SR]	= "SR",
+	[SNDRV_CHMAP_TC]	= "TC",
+	[SNDRV_CHMAP_TFL]	= "TFL",
+	[SNDRV_CHMAP_TFC]	= "TFC",
+	[SNDRV_CHMAP_TFR]	= "TFR",
+	[SNDRV_CHMAP_TRL]	= "TRL",
+	[SNDRV_CHMAP_TRC]	= "TRC",
+	[SNDRV_CHMAP_TRR]	= "TRR",
+	[SNDRV_CHMAP_TFLC]	= "TFLC",
+	[SNDRV_CHMAP_TFRC]	= "TFRC",
+	[SNDRV_CHMAP_LLFE]	= "LLFE",
+	[SNDRV_CHMAP_RLFE]	= "RLFE",
+	[SNDRV_CHMAP_TSL]	= "TSL",
+	[SNDRV_CHMAP_TSR]	= "TSR",
+	[SNDRV_CHMAP_BC]	= "BC",
+	[SNDRV_CHMAP_RLC]	= "RLC",
+	[SNDRV_CHMAP_RRC]	= "RRC",
+};
+
+/*
+ * proc interface for list the supported pcm formats
+ */
+static void proc_dump_substream_formats(struct snd_usb_substream *subs, struct snd_info_buffer *buffer)
+{
+	struct audioformat *fp;
+	static const char * const sync_types[4] = {
+		"NONE", "ASYNC", "ADAPTIVE", "SYNC"
+	};
+
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		snd_pcm_format_t fmt;
+
+		snd_iprintf(buffer, "  Interface %d\n", fp->iface);
+		snd_iprintf(buffer, "    Altset %d\n", fp->altsetting);
+		snd_iprintf(buffer, "    Format:");
+		pcm_for_each_format(fmt)
+			if (fp->formats & pcm_format_to_bits(fmt))
+				snd_iprintf(buffer, " %s",
+					    snd_pcm_format_name(fmt));
+		snd_iprintf(buffer, "\n");
+		snd_iprintf(buffer, "    Channels: %d\n", fp->channels);
+		snd_iprintf(buffer, "    Endpoint: 0x%02x (%d %s) (%s)\n",
+			    fp->endpoint,
+			    fp->endpoint & USB_ENDPOINT_NUMBER_MASK,
+			    fp->endpoint & USB_DIR_IN ? "IN" : "OUT",
+			    sync_types[(fp->ep_attr & USB_ENDPOINT_SYNCTYPE) >> 2]);
+		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS) {
+			snd_iprintf(buffer, "    Rates: %d - %d (continuous)\n",
+				    fp->rate_min, fp->rate_max);
+		} else {
+			unsigned int i;
+			snd_iprintf(buffer, "    Rates: ");
+			for (i = 0; i < fp->nr_rates; i++) {
+				if (i > 0)
+					snd_iprintf(buffer, ", ");
+				snd_iprintf(buffer, "%d", fp->rate_table[i]);
+			}
+			snd_iprintf(buffer, "\n");
+		}
+		if (subs->speed != USB_SPEED_FULL)
+			snd_iprintf(buffer, "    Data packet interval: %d us\n",
+				    125 * (1 << fp->datainterval));
+		snd_iprintf(buffer, "    Bits: %d\n", fp->fmt_bits);
+
+		if (fp->dsd_raw)
+			snd_iprintf(buffer, "    DSD raw: DOP=%d, bitrev=%d\n",
+				    fp->dsd_dop, fp->dsd_bitrev);
+
+		if (fp->chmap) {
+			const struct snd_pcm_chmap_elem *map = fp->chmap;
+			int c;
+
+			snd_iprintf(buffer, "    Channel map:");
+			for (c = 0; c < map->channels; c++) {
+				if (map->map[c] >= ARRAY_SIZE(channel_labels) ||
+				    !channel_labels[map->map[c]])
+					snd_iprintf(buffer, " --");
+				else
+					snd_iprintf(buffer, " %s",
+						    channel_labels[map->map[c]]);
+			}
+			snd_iprintf(buffer, "\n");
+		}
+
+		if (fp->sync_ep) {
+			snd_iprintf(buffer, "    Sync Endpoint: 0x%02x (%d %s)\n",
+				    fp->sync_ep,
+				    fp->sync_ep & USB_ENDPOINT_NUMBER_MASK,
+				    fp->sync_ep & USB_DIR_IN ? "IN" : "OUT");
+			snd_iprintf(buffer, "    Sync EP Interface: %d\n",
+				    fp->sync_iface);
+			snd_iprintf(buffer, "    Sync EP Altset: %d\n",
+				    fp->sync_altsetting);
+			snd_iprintf(buffer, "    Implicit Feedback Mode: %s\n",
+				    fp->implicit_fb ? "Yes" : "No");
+		}
+
+		// snd_iprintf(buffer, "    Max Packet Size = %d\n", fp->maxpacksize);
+		// snd_iprintf(buffer, "    EP Attribute = %#x\n", fp->attributes);
+	}
+}
+
+static void proc_dump_ep_status(struct snd_usb_substream *subs,
+				struct snd_usb_endpoint *data_ep,
+				struct snd_usb_endpoint *sync_ep,
+				struct snd_info_buffer *buffer)
+{
+	if (!data_ep)
+		return;
+	snd_iprintf(buffer, "    Packet Size = %d\n", data_ep->curpacksize);
+	snd_iprintf(buffer, "    Momentary freq = %u Hz (%#x.%04x)\n",
+		    subs->speed == USB_SPEED_FULL
+		    ? get_full_speed_hz(data_ep->freqm)
+		    : get_high_speed_hz(data_ep->freqm),
+		    data_ep->freqm >> 16, data_ep->freqm & 0xffff);
+	if (sync_ep && data_ep->freqshift != INT_MIN) {
+		int res = 16 - data_ep->freqshift;
+		snd_iprintf(buffer, "    Feedback Format = %d.%d\n",
+			    (sync_ep->syncmaxsize > 3 ? 32 : 24) - res, res);
+	}
+}
+
+static void proc_dump_substream_status(struct snd_usb_audio *chip,
+				       struct snd_usb_substream *subs,
+				       struct snd_info_buffer *buffer)
+{
+	guard(mutex)(&chip->mutex);
+	if (subs->running) {
+		snd_iprintf(buffer, "  Status: Running\n");
+		if (subs->cur_audiofmt) {
+			snd_iprintf(buffer, "    Interface = %d\n", subs->cur_audiofmt->iface);
+			snd_iprintf(buffer, "    Altset = %d\n", subs->cur_audiofmt->altsetting);
+		}
+		proc_dump_ep_status(subs, subs->data_endpoint, subs->sync_endpoint, buffer);
+	} else {
+		snd_iprintf(buffer, "  Status: Stop\n");
+	}
+}
+
+static void proc_pcm_format_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
+{
+	struct snd_usb_stream *stream = entry->private_data;
+	struct snd_usb_audio *chip = stream->chip;
+
+	snd_iprintf(buffer, "%s : %s\n", chip->card->longname, stream->pcm->name);
+
+	if (stream->substream[SNDRV_PCM_STREAM_PLAYBACK].num_formats) {
+		snd_iprintf(buffer, "\nPlayback:\n");
+		proc_dump_substream_status(chip, &stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
+		proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
+	}
+	if (stream->substream[SNDRV_PCM_STREAM_CAPTURE].num_formats) {
+		snd_iprintf(buffer, "\nCapture:\n");
+		proc_dump_substream_status(chip, &stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
+		proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
+	}
+}
+
+void snd_usb_proc_pcm_format_add(struct snd_usb_stream *stream)
+{
+	char name[32];
+	struct snd_card *card = stream->chip->card;
+
+	scnprintf(name, sizeof(name), "stream%d", stream->pcm_index);
+	snd_card_ro_proc_new(card, name, stream, proc_pcm_format_read);
+}
+
diff --git a/sound/usb/proc.h b/sound/usb/proc.h
new file mode 100644
index 000000000..72b1b2d28
--- /dev/null
+++ b/sound/usb/proc.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_PROC_H
+#define __USBAUDIO_PROC_H
+
+void snd_usb_audio_create_proc(struct snd_usb_audio *chip);
+void snd_usb_proc_pcm_format_add(struct snd_usb_stream *stream);
+
+#endif /* __USBAUDIO_PROC_H */
+
diff --git a/sound/usb/qcom/Makefile b/sound/usb/qcom/Makefile
new file mode 100644
index 000000000..aa8fcf8d2
--- /dev/null
+++ b/sound/usb/qcom/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+snd-usb-audio-qmi-y := usb_audio_qmi_v01.o qc_audio_offload.o
+snd-usb-audio-qmi-y += mixer_usb_offload.o
+obj-$(CONFIG_SND_USB_AUDIO_QMI) += snd-usb-audio-qmi.o
+
diff --git a/sound/usb/qcom/mixer_usb_offload.c b/sound/usb/qcom/mixer_usb_offload.c
new file mode 100644
index 000000000..b1591361e
--- /dev/null
+++ b/sound/usb/qcom/mixer_usb_offload.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022-2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/usb.h>
+
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/soc-usb.h>
+
+#include "../usbaudio.h"
+#include "../card.h"
+#include "../helper.h"
+#include "../mixer.h"
+
+#include "mixer_usb_offload.h"
+
+#define PCM_IDX(n)  ((n) & 0xffff)
+#define CARD_IDX(n) ((n) >> 16)
+
+static int
+snd_usb_offload_card_route_get(struct snd_kcontrol *kcontrol,
+			       struct snd_ctl_elem_value *ucontrol)
+{
+	struct device *sysdev = snd_kcontrol_chip(kcontrol);
+	int ret;
+
+	ret = snd_soc_usb_update_offload_route(sysdev,
+					       CARD_IDX(kcontrol->private_value),
+					       PCM_IDX(kcontrol->private_value),
+					       SNDRV_PCM_STREAM_PLAYBACK,
+					       SND_SOC_USB_KCTL_CARD_ROUTE,
+					       ucontrol->value.integer.value);
+	if (ret < 0) {
+		ucontrol->value.integer.value[0] = -1;
+		ucontrol->value.integer.value[1] = -1;
+	}
+
+	return 0;
+}
+
+static int snd_usb_offload_card_route_info(struct snd_kcontrol *kcontrol,
+					   struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = -1;
+	uinfo->value.integer.max = SNDRV_CARDS;
+
+	return 0;
+}
+
+static struct snd_kcontrol_new snd_usb_offload_mapped_card_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.info = snd_usb_offload_card_route_info,
+	.get = snd_usb_offload_card_route_get,
+};
+
+static int
+snd_usb_offload_pcm_route_get(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	struct device *sysdev = snd_kcontrol_chip(kcontrol);
+	int ret;
+
+	ret = snd_soc_usb_update_offload_route(sysdev,
+					       CARD_IDX(kcontrol->private_value),
+					       PCM_IDX(kcontrol->private_value),
+					       SNDRV_PCM_STREAM_PLAYBACK,
+					       SND_SOC_USB_KCTL_PCM_ROUTE,
+					       ucontrol->value.integer.value);
+	if (ret < 0) {
+		ucontrol->value.integer.value[0] = -1;
+		ucontrol->value.integer.value[1] = -1;
+	}
+
+	return 0;
+}
+
+static int snd_usb_offload_pcm_route_info(struct snd_kcontrol *kcontrol,
+					  struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = -1;
+	/* Arbitrary max value, as there is no 'limit' on number of PCM devices */
+	uinfo->value.integer.max = 0xff;
+
+	return 0;
+}
+
+static struct snd_kcontrol_new snd_usb_offload_mapped_pcm_ctl = {
+	.iface = SNDRV_CTL_ELEM_IFACE_CARD,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+	.info = snd_usb_offload_pcm_route_info,
+	.get = snd_usb_offload_pcm_route_get,
+};
+
+/**
+ * snd_usb_offload_create_ctl() - Add USB offload bounded mixer
+ * @chip: USB SND chip device
+ * @bedev: Reference to USB backend DAI device
+ *
+ * Creates a sound control for a USB audio device, so that applications can
+ * query for if there is an available USB audio offload path, and which
+ * card is managing it.
+ */
+int snd_usb_offload_create_ctl(struct snd_usb_audio *chip, struct device *bedev)
+{
+	struct snd_kcontrol_new *chip_kctl;
+	struct snd_usb_substream *subs;
+	struct snd_usb_stream *as;
+	char ctl_name[48];
+	int ret = 0;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		subs = &as->substream[SNDRV_PCM_STREAM_PLAYBACK];
+		if (!subs->ep_num || as->pcm_index > 0xff)
+			continue;
+
+		chip_kctl = &snd_usb_offload_mapped_card_ctl;
+		chip_kctl->count = 1;
+		/*
+		 * Store the associated USB SND card number and PCM index for
+		 * the kctl.
+		 */
+		chip_kctl->private_value = as->pcm_index |
+					  chip->card->number << 16;
+		snprintf(ctl_name, sizeof(ctl_name), "USB Offload Playback Card Route PCM#%d",
+			as->pcm_index);
+		chip_kctl->name = ctl_name;
+		ret = snd_ctl_add(chip->card, snd_ctl_new1(chip_kctl, bedev));
+		if (ret < 0)
+			break;
+
+		chip_kctl = &snd_usb_offload_mapped_pcm_ctl;
+		chip_kctl->count = 1;
+		/*
+		 * Store the associated USB SND card number and PCM index for
+		 * the kctl.
+		 */
+		chip_kctl->private_value = as->pcm_index |
+					  chip->card->number << 16;
+		snprintf(ctl_name, sizeof(ctl_name), "USB Offload Playback PCM Route PCM#%d",
+			as->pcm_index);
+		chip_kctl->name = ctl_name;
+		ret = snd_ctl_add(chip->card, snd_ctl_new1(chip_kctl, bedev));
+		if (ret < 0)
+			break;
+	}
+
+	return ret;
+}
diff --git a/sound/usb/qcom/mixer_usb_offload.h b/sound/usb/qcom/mixer_usb_offload.h
new file mode 100644
index 000000000..cf20673f4
--- /dev/null
+++ b/sound/usb/qcom/mixer_usb_offload.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (c) 2022-2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef __USB_OFFLOAD_MIXER_H
+#define __USB_OFFLOAD_MIXER_H
+
+int snd_usb_offload_create_ctl(struct snd_usb_audio *chip, struct device *bedev);
+
+#endif /* __USB_OFFLOAD_MIXER_H */
diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
new file mode 100644
index 000000000..e4bfd43a2
--- /dev/null
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -0,0 +1,2036 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/ctype.h>
+#include <linux/dma-mapping.h>
+#include <linux/dma-map-ops.h>
+#include <linux/init.h>
+#include <linux/iommu.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/soc/qcom/qmi.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/quirks.h>
+#include <linux/usb/xhci-sideband.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/q6usboffload.h>
+#include <sound/soc.h>
+#include <sound/soc-usb.h>
+
+#include "../usbaudio.h"
+#include "../card.h"
+#include "../endpoint.h"
+#include "../format.h"
+#include "../helper.h"
+#include "../pcm.h"
+#include "../power.h"
+
+#include "mixer_usb_offload.h"
+#include "usb_audio_qmi_v01.h"
+
+/* Stream disable request timeout during USB device disconnect */
+#define DEV_RELEASE_WAIT_TIMEOUT 10000 /* in ms */
+
+/* Data interval calculation parameters */
+#define BUS_INTERVAL_FULL_SPEED 1000 /* in us */
+#define BUS_INTERVAL_HIGHSPEED_AND_ABOVE 125 /* in us */
+#define MAX_BINTERVAL_ISOC_EP 16
+
+#define QMI_STREAM_REQ_CARD_NUM_MASK 0xffff0000
+#define QMI_STREAM_REQ_DEV_NUM_MASK 0xff00
+#define QMI_STREAM_REQ_DIRECTION 0xff
+
+/* iommu resource parameters and management */
+#define PREPEND_SID_TO_IOVA(iova, sid) ((u64)(((u64)(iova)) | \
+					(((u64)sid) << 32)))
+#define IOVA_MASK(iova) (((u64)(iova)) & 0xFFFFFFFF)
+#define IOVA_BASE 0x1000
+#define IOVA_XFER_RING_BASE (IOVA_BASE + PAGE_SIZE * (SNDRV_CARDS + 1))
+#define IOVA_XFER_BUF_BASE (IOVA_XFER_RING_BASE + PAGE_SIZE * SNDRV_CARDS * 32)
+#define IOVA_XFER_RING_MAX (IOVA_XFER_BUF_BASE - PAGE_SIZE)
+#define IOVA_XFER_BUF_MAX (0xfffff000 - PAGE_SIZE)
+
+#define MAX_XFER_BUFF_LEN (24 * PAGE_SIZE)
+
+struct iova_info {
+	struct list_head list;
+	unsigned long start_iova;
+	size_t size;
+	bool in_use;
+};
+
+struct intf_info {
+	/* IOMMU ring/buffer mapping information */
+	unsigned long data_xfer_ring_va;
+	size_t data_xfer_ring_size;
+	unsigned long sync_xfer_ring_va;
+	size_t sync_xfer_ring_size;
+	dma_addr_t xfer_buf_iova;
+	size_t xfer_buf_size;
+	dma_addr_t xfer_buf_dma;
+	u8 *xfer_buf_cpu;
+
+	/* USB endpoint information */
+	unsigned int data_ep_pipe;
+	unsigned int sync_ep_pipe;
+	unsigned int data_ep_idx;
+	unsigned int sync_ep_idx;
+
+	u8 intf_num;
+	u8 pcm_card_num;
+	u8 pcm_dev_num;
+	u8 direction;
+	bool in_use;
+};
+
+struct uaudio_qmi_dev {
+	struct device *dev;
+	struct q6usb_offload *data;
+	struct auxiliary_device *auxdev;
+
+	/* list to keep track of available iova */
+	struct list_head xfer_ring_list;
+	size_t xfer_ring_iova_size;
+	unsigned long curr_xfer_ring_iova;
+	struct list_head xfer_buf_list;
+	size_t xfer_buf_iova_size;
+	unsigned long curr_xfer_buf_iova;
+
+	/* bit fields representing pcm card enabled */
+	unsigned long card_slot;
+	/* indicate event ring mapped or not */
+	bool er_mapped;
+};
+
+struct uaudio_dev {
+	struct usb_device *udev;
+	/* audio control interface */
+	struct usb_host_interface *ctrl_intf;
+	unsigned int usb_core_id;
+	atomic_t in_use;
+	struct kref kref;
+	wait_queue_head_t disconnect_wq;
+
+	/* interface specific */
+	int num_intf;
+	struct intf_info *info;
+	struct snd_usb_audio *chip;
+
+	/* xhci sideband */
+	struct xhci_sideband *sb;
+
+	/* SoC USB device */
+	struct snd_soc_usb_device *sdev;
+};
+
+static struct uaudio_dev uadev[SNDRV_CARDS];
+static struct uaudio_qmi_dev *uaudio_qdev;
+static struct uaudio_qmi_svc *uaudio_svc;
+static DEFINE_MUTEX(qdev_mutex);
+
+struct uaudio_qmi_svc {
+	struct qmi_handle *uaudio_svc_hdl;
+	struct sockaddr_qrtr client_sq;
+	bool client_connected;
+};
+
+enum mem_type {
+	MEM_EVENT_RING,
+	MEM_XFER_RING,
+	MEM_XFER_BUF,
+};
+
+/* Supported audio formats */
+enum usb_qmi_audio_format {
+	USB_QMI_PCM_FORMAT_S8 = 0,
+	USB_QMI_PCM_FORMAT_U8,
+	USB_QMI_PCM_FORMAT_S16_LE,
+	USB_QMI_PCM_FORMAT_S16_BE,
+	USB_QMI_PCM_FORMAT_U16_LE,
+	USB_QMI_PCM_FORMAT_U16_BE,
+	USB_QMI_PCM_FORMAT_S24_LE,
+	USB_QMI_PCM_FORMAT_S24_BE,
+	USB_QMI_PCM_FORMAT_U24_LE,
+	USB_QMI_PCM_FORMAT_U24_BE,
+	USB_QMI_PCM_FORMAT_S24_3LE,
+	USB_QMI_PCM_FORMAT_S24_3BE,
+	USB_QMI_PCM_FORMAT_U24_3LE,
+	USB_QMI_PCM_FORMAT_U24_3BE,
+	USB_QMI_PCM_FORMAT_S32_LE,
+	USB_QMI_PCM_FORMAT_S32_BE,
+	USB_QMI_PCM_FORMAT_U32_LE,
+	USB_QMI_PCM_FORMAT_U32_BE,
+};
+
+static int usb_qmi_get_pcm_num(struct snd_usb_audio *chip, int direction)
+{
+	struct snd_usb_substream *subs = NULL;
+	struct snd_usb_stream *as;
+	int count = 0;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		subs = &as->substream[direction];
+		if (subs->ep_num)
+			count++;
+	}
+
+	return count;
+}
+
+static enum usb_qmi_audio_device_speed_enum_v01
+get_speed_info(enum usb_device_speed udev_speed)
+{
+	switch (udev_speed) {
+	case USB_SPEED_LOW:
+		return USB_QMI_DEVICE_SPEED_LOW_V01;
+	case USB_SPEED_FULL:
+		return USB_QMI_DEVICE_SPEED_FULL_V01;
+	case USB_SPEED_HIGH:
+		return USB_QMI_DEVICE_SPEED_HIGH_V01;
+	case USB_SPEED_SUPER:
+		return USB_QMI_DEVICE_SPEED_SUPER_V01;
+	case USB_SPEED_SUPER_PLUS:
+		return USB_QMI_DEVICE_SPEED_SUPER_PLUS_V01;
+	default:
+		return USB_QMI_DEVICE_SPEED_INVALID_V01;
+	}
+}
+
+static struct snd_usb_substream *find_substream(unsigned int card_num,
+						unsigned int pcm_idx,
+						unsigned int direction)
+{
+	struct snd_usb_substream *subs = NULL;
+	struct snd_usb_audio *chip;
+	struct snd_usb_stream *as;
+
+	chip = uadev[card_num].chip;
+	if (!chip || atomic_read(&chip->shutdown))
+		goto done;
+
+	if (pcm_idx >= chip->pcm_devs)
+		goto done;
+
+	if (direction > SNDRV_PCM_STREAM_CAPTURE)
+		goto done;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		if (as->pcm_index == pcm_idx) {
+			subs = &as->substream[direction];
+			goto done;
+		}
+	}
+
+done:
+	return subs;
+}
+
+static int info_idx_from_ifnum(int card_num, int intf_num, bool enable)
+{
+	int i;
+
+	/*
+	 * default index 0 is used when info is allocated upon
+	 * first enable audio stream req for a pcm device
+	 */
+	if (enable && !uadev[card_num].info)
+		return 0;
+
+	for (i = 0; i < uadev[card_num].num_intf; i++) {
+		if (enable && !uadev[card_num].info[i].in_use)
+			return i;
+		else if (!enable &&
+			 uadev[card_num].info[i].intf_num == intf_num)
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int get_data_interval_from_si(struct snd_usb_substream *subs,
+				     u32 service_interval)
+{
+	unsigned int bus_intval_mult;
+	unsigned int bus_intval;
+	unsigned int binterval;
+
+	if (subs->dev->speed >= USB_SPEED_HIGH)
+		bus_intval = BUS_INTERVAL_HIGHSPEED_AND_ABOVE;
+	else
+		bus_intval = BUS_INTERVAL_FULL_SPEED;
+
+	if (service_interval % bus_intval)
+		return -EINVAL;
+
+	bus_intval_mult = service_interval / bus_intval;
+	binterval = ffs(bus_intval_mult);
+	if (!binterval || binterval > MAX_BINTERVAL_ISOC_EP)
+		return -EINVAL;
+
+	/* check if another bit is set then bail out */
+	bus_intval_mult = bus_intval_mult >> binterval;
+	if (bus_intval_mult)
+		return -EINVAL;
+
+	return (binterval - 1);
+}
+
+/* maps audio format received over QMI to asound.h based pcm format */
+static snd_pcm_format_t map_pcm_format(enum usb_qmi_audio_format fmt_received)
+{
+	switch (fmt_received) {
+	case USB_QMI_PCM_FORMAT_S8:
+		return SNDRV_PCM_FORMAT_S8;
+	case USB_QMI_PCM_FORMAT_U8:
+		return SNDRV_PCM_FORMAT_U8;
+	case USB_QMI_PCM_FORMAT_S16_LE:
+		return SNDRV_PCM_FORMAT_S16_LE;
+	case USB_QMI_PCM_FORMAT_S16_BE:
+		return SNDRV_PCM_FORMAT_S16_BE;
+	case USB_QMI_PCM_FORMAT_U16_LE:
+		return SNDRV_PCM_FORMAT_U16_LE;
+	case USB_QMI_PCM_FORMAT_U16_BE:
+		return SNDRV_PCM_FORMAT_U16_BE;
+	case USB_QMI_PCM_FORMAT_S24_LE:
+		return SNDRV_PCM_FORMAT_S24_LE;
+	case USB_QMI_PCM_FORMAT_S24_BE:
+		return SNDRV_PCM_FORMAT_S24_BE;
+	case USB_QMI_PCM_FORMAT_U24_LE:
+		return SNDRV_PCM_FORMAT_U24_LE;
+	case USB_QMI_PCM_FORMAT_U24_BE:
+		return SNDRV_PCM_FORMAT_U24_BE;
+	case USB_QMI_PCM_FORMAT_S24_3LE:
+		return SNDRV_PCM_FORMAT_S24_3LE;
+	case USB_QMI_PCM_FORMAT_S24_3BE:
+		return SNDRV_PCM_FORMAT_S24_3BE;
+	case USB_QMI_PCM_FORMAT_U24_3LE:
+		return SNDRV_PCM_FORMAT_U24_3LE;
+	case USB_QMI_PCM_FORMAT_U24_3BE:
+		return SNDRV_PCM_FORMAT_U24_3BE;
+	case USB_QMI_PCM_FORMAT_S32_LE:
+		return SNDRV_PCM_FORMAT_S32_LE;
+	case USB_QMI_PCM_FORMAT_S32_BE:
+		return SNDRV_PCM_FORMAT_S32_BE;
+	case USB_QMI_PCM_FORMAT_U32_LE:
+		return SNDRV_PCM_FORMAT_U32_LE;
+	case USB_QMI_PCM_FORMAT_U32_BE:
+		return SNDRV_PCM_FORMAT_U32_BE;
+	default:
+		/*
+		 * We expect the caller to do input validation so we should
+		 * never hit this. But we do have to return a proper
+		 * snd_pcm_format_t value due to the __bitwise attribute; so
+		 * just return the equivalent of 0 in case of bad input.
+		 */
+		return SNDRV_PCM_FORMAT_S8;
+	}
+}
+
+/*
+ * Sends QMI disconnect indication message, assumes chip->mutex and qdev_mutex
+ * lock held by caller.
+ */
+static int uaudio_send_disconnect_ind(struct snd_usb_audio *chip)
+{
+	struct qmi_uaudio_stream_ind_msg_v01 disconnect_ind = {0};
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+	struct uaudio_dev *dev;
+	int ret = 0;
+
+	dev = &uadev[chip->card->number];
+
+	if (atomic_read(&dev->in_use)) {
+		mutex_unlock(&chip->mutex);
+		mutex_unlock(&qdev_mutex);
+		dev_dbg(uaudio_qdev->data->dev, "sending qmi indication suspend\n");
+		disconnect_ind.dev_event = USB_QMI_DEV_DISCONNECT_V01;
+		disconnect_ind.slot_id = dev->udev->slot_id;
+		disconnect_ind.controller_num = dev->usb_core_id;
+		disconnect_ind.controller_num_valid = 1;
+		ret = qmi_send_indication(svc->uaudio_svc_hdl, &svc->client_sq,
+					  QMI_UAUDIO_STREAM_IND_V01,
+					  QMI_UAUDIO_STREAM_IND_MSG_V01_MAX_MSG_LEN,
+					  qmi_uaudio_stream_ind_msg_v01_ei,
+					  &disconnect_ind);
+		if (ret < 0)
+			dev_err(uaudio_qdev->data->dev,
+				"qmi send failed with err: %d\n", ret);
+
+		ret = wait_event_interruptible_timeout(dev->disconnect_wq,
+				!atomic_read(&dev->in_use),
+				msecs_to_jiffies(DEV_RELEASE_WAIT_TIMEOUT));
+		if (!ret) {
+			dev_err(uaudio_qdev->data->dev,
+				"timeout while waiting for dev_release\n");
+			atomic_set(&dev->in_use, 0);
+		} else if (ret < 0) {
+			dev_err(uaudio_qdev->data->dev,
+				"failed with ret %d\n", ret);
+			atomic_set(&dev->in_use, 0);
+		}
+		mutex_lock(&qdev_mutex);
+		mutex_lock(&chip->mutex);
+	}
+
+	return ret;
+}
+
+/* Offloading IOMMU management */
+static unsigned long uaudio_get_iova(unsigned long *curr_iova,
+				     size_t *curr_iova_size,
+				     struct list_head *head, size_t size)
+{
+	struct iova_info *info, *new_info = NULL;
+	struct list_head *curr_head;
+	size_t tmp_size = size;
+	unsigned long iova = 0;
+
+	if (size % PAGE_SIZE)
+		goto done;
+
+	if (size > *curr_iova_size)
+		goto done;
+
+	if (*curr_iova_size == 0)
+		goto done;
+
+	list_for_each_entry(info, head, list) {
+		/* exact size iova_info */
+		if (!info->in_use && info->size == size) {
+			info->in_use = true;
+			iova = info->start_iova;
+			*curr_iova_size -= size;
+			goto done;
+		} else if (!info->in_use && tmp_size >= info->size) {
+			if (!new_info)
+				new_info = info;
+			tmp_size -= info->size;
+			if (tmp_size)
+				continue;
+
+			iova = new_info->start_iova;
+			for (curr_head = &new_info->list; curr_head !=
+			&info->list; curr_head = curr_head->next) {
+				new_info = list_entry(curr_head, struct
+						iova_info, list);
+				new_info->in_use = true;
+			}
+			info->in_use = true;
+			*curr_iova_size -= size;
+			goto done;
+		} else {
+			/* iova region in use */
+			new_info = NULL;
+			tmp_size = size;
+		}
+	}
+
+	info = kzalloc_obj(*info);
+	if (!info) {
+		iova = 0;
+		goto done;
+	}
+
+	iova = *curr_iova;
+	info->start_iova = *curr_iova;
+	info->size = size;
+	info->in_use = true;
+	*curr_iova += size;
+	*curr_iova_size -= size;
+	list_add_tail(&info->list, head);
+
+done:
+	return iova;
+}
+
+static void uaudio_put_iova(unsigned long iova, size_t size, struct list_head
+	*head, size_t *curr_iova_size)
+{
+	struct iova_info *info;
+	size_t tmp_size = size;
+	bool found = false;
+
+	list_for_each_entry(info, head, list) {
+		if (info->start_iova == iova) {
+			if (!info->in_use)
+				return;
+
+			found = true;
+			info->in_use = false;
+			if (info->size == size)
+				goto done;
+		}
+
+		if (found && tmp_size >= info->size) {
+			info->in_use = false;
+			tmp_size -= info->size;
+			if (!tmp_size)
+				goto done;
+		}
+	}
+
+	if (!found)
+		return;
+
+done:
+	*curr_iova_size += size;
+}
+
+/**
+ * uaudio_iommu_unmap() - unmaps iommu memory for adsp
+ * @mtype: ring type
+ * @iova: virtual address to unmap
+ * @iova_size: region size
+ * @mapped_iova_size: mapped region size
+ *
+ * Unmaps the memory region that was previously assigned to the adsp.
+ *
+ */
+static void uaudio_iommu_unmap(enum mem_type mtype, unsigned long iova,
+			       size_t iova_size, size_t mapped_iova_size)
+{
+	size_t umap_size;
+	bool unmap = true;
+
+	if (!iova || !iova_size)
+		return;
+
+	switch (mtype) {
+	case MEM_EVENT_RING:
+		if (uaudio_qdev->er_mapped)
+			uaudio_qdev->er_mapped = false;
+		else
+			unmap = false;
+		break;
+
+	case MEM_XFER_RING:
+		uaudio_put_iova(iova, iova_size, &uaudio_qdev->xfer_ring_list,
+				&uaudio_qdev->xfer_ring_iova_size);
+		break;
+	case MEM_XFER_BUF:
+		uaudio_put_iova(iova, iova_size, &uaudio_qdev->xfer_buf_list,
+				&uaudio_qdev->xfer_buf_iova_size);
+		break;
+	default:
+		unmap = false;
+	}
+
+	if (!unmap || !mapped_iova_size)
+		return;
+
+	umap_size = iommu_unmap(uaudio_qdev->data->domain, iova, mapped_iova_size);
+	if (umap_size != mapped_iova_size)
+		dev_err(uaudio_qdev->data->dev,
+			"unmapped size %zu for iova 0x%08lx of mapped size %zu\n",
+			umap_size, iova, mapped_iova_size);
+}
+
+static int uaudio_iommu_map_prot(bool dma_coherent)
+{
+	int prot = IOMMU_READ | IOMMU_WRITE;
+
+	if (dma_coherent)
+		prot |= IOMMU_CACHE;
+	return prot;
+}
+
+/**
+ * uaudio_iommu_map_pa() - maps iommu memory for adsp
+ * @mtype: ring type
+ * @dma_coherent: dma coherent
+ * @pa: physical address for ring/buffer
+ * @size: size of memory region
+ *
+ * Maps the XHCI related resources to a memory region that is assigned to be
+ * used by the adsp.  This will be mapped to the domain, which is created by
+ * the ASoC USB backend driver.
+ *
+ */
+static unsigned long uaudio_iommu_map_pa(enum mem_type mtype, bool dma_coherent,
+					 phys_addr_t pa, size_t size)
+{
+	unsigned long iova = 0;
+	bool map = true;
+	int prot = uaudio_iommu_map_prot(dma_coherent);
+	int ret;
+
+	switch (mtype) {
+	case MEM_EVENT_RING:
+		iova = IOVA_BASE;
+		/* er already mapped */
+		if (uaudio_qdev->er_mapped)
+			map = false;
+		break;
+	case MEM_XFER_RING:
+		iova = uaudio_get_iova(&uaudio_qdev->curr_xfer_ring_iova,
+				     &uaudio_qdev->xfer_ring_iova_size,
+				     &uaudio_qdev->xfer_ring_list, size);
+		break;
+	default:
+		dev_err(uaudio_qdev->data->dev, "unknown mem type %d\n", mtype);
+	}
+
+	if (!iova)
+		return 0;
+
+	if (!map)
+		return iova;
+
+	ret = iommu_map(uaudio_qdev->data->domain, iova, pa, size, prot,
+			GFP_KERNEL);
+	if (ret) {
+		dev_err(uaudio_qdev->data->dev,
+			"failed to map %zu bytes at iova 0x%08lx: %d\n",
+			size, iova, ret);
+		if (mtype == MEM_XFER_RING)
+			uaudio_put_iova(iova, size,
+					&uaudio_qdev->xfer_ring_list,
+					&uaudio_qdev->xfer_ring_iova_size);
+		return 0;
+	}
+
+	return iova;
+}
+
+static unsigned long uaudio_iommu_map_xfer_buf(bool dma_coherent, size_t size,
+					       struct sg_table *sgt)
+{
+	struct scatterlist *sg;
+	unsigned long iova = 0;
+	size_t total_len = 0;
+	unsigned long iova_sg;
+	phys_addr_t pa_sg;
+	size_t sg_len;
+	int prot = uaudio_iommu_map_prot(dma_coherent);
+	int ret;
+	int i;
+
+	prot = IOMMU_READ | IOMMU_WRITE;
+
+	if (dma_coherent)
+		prot |= IOMMU_CACHE;
+
+	iova = uaudio_get_iova(&uaudio_qdev->curr_xfer_buf_iova,
+			       &uaudio_qdev->xfer_buf_iova_size,
+			       &uaudio_qdev->xfer_buf_list, size);
+	if (!iova)
+		goto done;
+
+	iova_sg = iova;
+	for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+		sg_len = PAGE_ALIGN(sg->offset + sg->length);
+		pa_sg = page_to_phys(sg_page(sg));
+		ret = iommu_map(uaudio_qdev->data->domain, iova_sg, pa_sg, sg_len,
+				prot, GFP_KERNEL);
+		if (ret) {
+			uaudio_iommu_unmap(MEM_XFER_BUF, iova, size, total_len);
+			iova = 0;
+			goto done;
+		}
+
+		iova_sg += sg_len;
+		total_len += sg_len;
+	}
+
+	if (size != total_len) {
+		uaudio_iommu_unmap(MEM_XFER_BUF, iova, size, total_len);
+		iova = 0;
+	}
+done:
+	return iova;
+}
+
+/* looks up alias, if any, for controller DT node and returns the index */
+static int usb_get_controller_id(struct usb_device *udev)
+{
+	if (udev->bus->sysdev && udev->bus->sysdev->of_node)
+		return of_alias_get_id(udev->bus->sysdev->of_node, "usb");
+
+	return -ENODEV;
+}
+
+/**
+ * uaudio_dev_intf_cleanup() - cleanup transfer resources
+ * @udev: usb device
+ * @info: usb offloading interface
+ *
+ * Cleans up the transfer ring related resources which are assigned per
+ * endpoint from XHCI.  This is invoked when the USB endpoints are no
+ * longer in use by the adsp.
+ *
+ */
+static void uaudio_dev_intf_cleanup(struct usb_device *udev, struct intf_info *info)
+{
+	uaudio_iommu_unmap(MEM_XFER_RING, info->data_xfer_ring_va,
+			   info->data_xfer_ring_size, info->data_xfer_ring_size);
+	info->data_xfer_ring_va = 0;
+	info->data_xfer_ring_size = 0;
+
+	uaudio_iommu_unmap(MEM_XFER_RING, info->sync_xfer_ring_va,
+			   info->sync_xfer_ring_size, info->sync_xfer_ring_size);
+	info->sync_xfer_ring_va = 0;
+	info->sync_xfer_ring_size = 0;
+
+	uaudio_iommu_unmap(MEM_XFER_BUF, info->xfer_buf_iova, info->xfer_buf_size,
+			   info->xfer_buf_size);
+	info->xfer_buf_iova = 0;
+
+	usb_free_coherent(udev, info->xfer_buf_size, info->xfer_buf_cpu,
+			  info->xfer_buf_dma);
+	info->xfer_buf_size = 0;
+	info->xfer_buf_cpu = NULL;
+	info->xfer_buf_dma = 0;
+
+	info->in_use = false;
+}
+
+/**
+ * uaudio_event_ring_cleanup_free() - cleanup secondary event ring
+ * @dev: usb offload device
+ *
+ * Cleans up the secondary event ring that was requested.  This will
+ * occur when the adsp is no longer transferring data on the USB bus
+ * across all endpoints.
+ *
+ */
+static void uaudio_event_ring_cleanup_free(struct uaudio_dev *dev)
+{
+	clear_bit(dev->chip->card->number, &uaudio_qdev->card_slot);
+	/* all audio devices are disconnected */
+	if (!uaudio_qdev->card_slot) {
+		uaudio_iommu_unmap(MEM_EVENT_RING, IOVA_BASE, PAGE_SIZE,
+				   PAGE_SIZE);
+		xhci_sideband_remove_interrupter(uadev[dev->chip->card->number].sb);
+		usb_offload_put(dev->udev);
+	}
+}
+
+static void uaudio_dev_cleanup(struct uaudio_dev *dev)
+{
+	int if_idx;
+
+	if (!dev->udev)
+		return;
+
+	/* free xfer buffer and unmap xfer ring and buf per interface */
+	for (if_idx = 0; if_idx < dev->num_intf; if_idx++) {
+		if (!dev->info[if_idx].in_use)
+			continue;
+		uaudio_dev_intf_cleanup(dev->udev, &dev->info[if_idx]);
+		dev_dbg(uaudio_qdev->data->dev,
+			"release resources: intf# %d card# %d\n",
+			dev->info[if_idx].intf_num, dev->chip->card->number);
+	}
+
+	dev->num_intf = 0;
+
+	/* free interface info */
+	kfree(dev->info);
+	dev->info = NULL;
+	uaudio_event_ring_cleanup_free(dev);
+	dev->udev = NULL;
+}
+
+/**
+ * disable_audio_stream() - disable usb snd endpoints
+ * @subs: usb substream
+ *
+ * Closes the USB SND endpoints associated with the current audio stream
+ * used.  This will decrement the USB SND endpoint opened reference count.
+ *
+ */
+static void disable_audio_stream(struct snd_usb_substream *subs)
+{
+	struct snd_usb_audio *chip = subs->stream->chip;
+
+	snd_usb_hw_free(subs);
+	snd_usb_autosuspend(chip);
+}
+
+/* QMI service disconnect handlers */
+static void qmi_stop_session(void)
+{
+	struct snd_usb_substream *subs;
+	struct usb_host_endpoint *ep;
+	struct snd_usb_audio *chip;
+	struct intf_info *info;
+	int pcm_card_num;
+	int if_idx;
+	int idx;
+
+	guard(mutex)(&qdev_mutex);
+	/* find all active intf for set alt 0 and cleanup usb audio dev */
+	for (idx = 0; idx < SNDRV_CARDS; idx++) {
+		if (!atomic_read(&uadev[idx].in_use))
+			continue;
+
+		chip = uadev[idx].chip;
+		for (if_idx = 0; if_idx < uadev[idx].num_intf; if_idx++) {
+			if (!uadev[idx].info || !uadev[idx].info[if_idx].in_use)
+				continue;
+			info = &uadev[idx].info[if_idx];
+			pcm_card_num = info->pcm_card_num;
+			subs = find_substream(pcm_card_num, info->pcm_dev_num,
+					      info->direction);
+			if (!subs || !chip || atomic_read(&chip->shutdown)) {
+				dev_err(&uadev[idx].udev->dev,
+					"no sub for c#%u dev#%u dir%u\n",
+					info->pcm_card_num,
+					info->pcm_dev_num,
+					info->direction);
+				continue;
+			}
+			/* Release XHCI endpoints */
+			if (info->data_ep_pipe) {
+				ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
+						       info->data_ep_pipe);
+				if (ep)
+					xhci_sideband_remove_endpoint(uadev[pcm_card_num].sb,
+								      ep);
+				info->data_ep_pipe = 0;
+			}
+
+			if (info->sync_ep_pipe) {
+				ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
+						       info->sync_ep_pipe);
+				if (ep)
+					xhci_sideband_remove_endpoint(uadev[pcm_card_num].sb,
+								      ep);
+				info->sync_ep_pipe = 0;
+			}
+
+			disable_audio_stream(subs);
+		}
+		atomic_set(&uadev[idx].in_use, 0);
+		guard(mutex)(&chip->mutex);
+		uaudio_dev_cleanup(&uadev[idx]);
+	}
+}
+
+/**
+ * uaudio_sideband_notifier() - xHCI sideband event handler
+ * @intf: USB interface handle
+ * @evt: xHCI sideband event type
+ *
+ * This callback is executed when the xHCI sideband encounters a sequence
+ * that requires the sideband clients to take action.  An example, is when
+ * xHCI frees the transfer ring, so the client has to ensure that the
+ * offload path is halted.
+ *
+ */
+static int uaudio_sideband_notifier(struct usb_interface *intf,
+				    struct xhci_sideband_event *evt)
+{
+	struct snd_usb_audio *chip;
+	struct uaudio_dev *dev;
+	int if_idx;
+
+	if (!intf || !evt)
+		return 0;
+
+	chip = usb_get_intfdata(intf);
+
+	guard(mutex)(&qdev_mutex);
+	guard(mutex)(&chip->mutex);
+
+	dev = &uadev[chip->card->number];
+
+	if (evt->type == XHCI_SIDEBAND_XFER_RING_FREE) {
+		unsigned int *ep = (unsigned int *) evt->evt_data;
+
+		for (if_idx = 0; if_idx < dev->num_intf; if_idx++) {
+			if (dev->info[if_idx].data_ep_idx == *ep ||
+			    dev->info[if_idx].sync_ep_idx == *ep)
+				uaudio_send_disconnect_ind(chip);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * qmi_bye_cb() - qmi bye message callback
+ * @handle: QMI handle
+ * @node: id of the dying node
+ *
+ * This callback is invoked when the QMI bye control message is received
+ * from the QMI client.  Handle the message accordingly by ensuring that
+ * the USB offload path is disabled and cleaned up.  At this point, ADSP
+ * is not utilizing the USB bus.
+ *
+ */
+static void qmi_bye_cb(struct qmi_handle *handle, unsigned int node)
+{
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+
+	if (svc->uaudio_svc_hdl != handle)
+		return;
+
+	if (svc->client_connected && svc->client_sq.sq_node == node) {
+		qmi_stop_session();
+
+		/* clear QMI client parameters to block further QMI messages */
+		svc->client_sq.sq_node = 0;
+		svc->client_sq.sq_port = 0;
+		svc->client_sq.sq_family = 0;
+		svc->client_connected = false;
+	}
+}
+
+/**
+ * qmi_svc_disconnect_cb() - qmi client disconnected
+ * @handle: QMI handle
+ * @node: id of the dying node
+ * @port: port of the dying client
+ *
+ * Invoked when the remote QMI client is disconnected.  Handle this event
+ * the same way as when the QMI bye message is received.  This will ensure
+ * the USB offloading path is disabled and cleaned up.
+ *
+ */
+static void qmi_svc_disconnect_cb(struct qmi_handle *handle,
+				  unsigned int node, unsigned int port)
+{
+	struct uaudio_qmi_svc *svc;
+
+	if (!uaudio_svc)
+		return;
+
+	svc = uaudio_svc;
+	if (svc->uaudio_svc_hdl != handle)
+		return;
+
+	if (svc->client_connected && svc->client_sq.sq_node == node &&
+	    svc->client_sq.sq_port == port) {
+		qmi_stop_session();
+
+		/* clear QMI client parameters to block further QMI messages */
+		svc->client_sq.sq_node = 0;
+		svc->client_sq.sq_port = 0;
+		svc->client_sq.sq_family = 0;
+		svc->client_connected = false;
+	}
+}
+
+/* QMI client callback handlers from QMI interface */
+static struct qmi_ops uaudio_svc_ops_options = {
+	.bye = qmi_bye_cb,
+	.del_client = qmi_svc_disconnect_cb,
+};
+
+/* kref release callback when all streams are disabled */
+static void uaudio_dev_release(struct kref *kref)
+{
+	struct uaudio_dev *dev = container_of(kref, struct uaudio_dev, kref);
+
+	uaudio_event_ring_cleanup_free(dev);
+	atomic_set(&dev->in_use, 0);
+	wake_up(&dev->disconnect_wq);
+}
+
+/**
+ * enable_audio_stream() - enable usb snd endpoints
+ * @subs: usb substream
+ * @pcm_format: pcm format requested
+ * @channels: number of channels
+ * @cur_rate: sample rate
+ * @datainterval: interval
+ *
+ * Opens all USB SND endpoints used for the data interface.  This will increment
+ * the USB SND endpoint's opened count.  Requests to keep the interface resumed
+ * until the audio stream is stopped.  Will issue the USB set interface control
+ * message to enable the data interface.
+ *
+ */
+static int enable_audio_stream(struct snd_usb_substream *subs,
+			       snd_pcm_format_t pcm_format,
+			       unsigned int channels, unsigned int cur_rate,
+			       int datainterval)
+{
+	struct snd_pcm_hw_params params;
+	struct snd_usb_audio *chip;
+	struct snd_interval *i;
+	struct snd_mask *m;
+	int ret;
+
+	chip = subs->stream->chip;
+
+	_snd_pcm_hw_params_any(&params);
+
+	m = hw_param_mask(&params, SNDRV_PCM_HW_PARAM_FORMAT);
+	snd_mask_leave(m, (__force unsigned int)pcm_format);
+
+	i = hw_param_interval(&params, SNDRV_PCM_HW_PARAM_CHANNELS);
+	snd_interval_setinteger(i);
+	i->min = channels;
+	i->max = channels;
+
+	i = hw_param_interval(&params, SNDRV_PCM_HW_PARAM_RATE);
+	snd_interval_setinteger(i);
+	i->min = cur_rate;
+	i->max = cur_rate;
+
+	pm_runtime_barrier(&chip->intf[0]->dev);
+	snd_usb_autoresume(chip);
+
+	ret = snd_usb_hw_params(subs, &params);
+	if (ret < 0)
+		goto put_suspend;
+
+	if (!atomic_read(&chip->shutdown)) {
+		CLASS(snd_usb_lock, pm)(chip);
+		if (pm.err < 0) {
+			ret = pm.err;
+			goto detach_ep;
+		}
+
+		if (subs->sync_endpoint) {
+			ret = snd_usb_endpoint_prepare(chip, subs->sync_endpoint);
+			if (ret < 0)
+				goto detach_ep;
+		}
+
+		ret = snd_usb_endpoint_prepare(chip, subs->data_endpoint);
+		if (ret < 0)
+			goto detach_ep;
+
+		dev_dbg(uaudio_qdev->data->dev,
+			"selected %s iface:%d altsetting:%d datainterval:%dus\n",
+			subs->direction ? "capture" : "playback",
+			subs->cur_audiofmt->iface, subs->cur_audiofmt->altsetting,
+			(1 << subs->cur_audiofmt->datainterval) *
+			(subs->dev->speed >= USB_SPEED_HIGH ?
+			BUS_INTERVAL_HIGHSPEED_AND_ABOVE :
+			BUS_INTERVAL_FULL_SPEED));
+	}
+
+	return 0;
+
+detach_ep:
+	snd_usb_hw_free(subs);
+
+put_suspend:
+	snd_usb_autosuspend(chip);
+
+	return ret;
+}
+
+/**
+ * uaudio_transfer_buffer_setup() - fetch and populate xfer buffer params
+ * @subs: usb substream
+ * @xfer_buf_cpu: xfer buf to be allocated
+ * @xfer_buf_len: size of allocation
+ * @mem_info: QMI response info
+ *
+ * Allocates and maps the transfer buffers that will be utilized by the
+ * audio DSP.  Will populate the information in the QMI response that is
+ * sent back to the stream enable request.
+ *
+ */
+static int uaudio_transfer_buffer_setup(struct snd_usb_substream *subs,
+					void **xfer_buf_cpu, u32 xfer_buf_len,
+					struct mem_info_v01 *mem_info)
+{
+	struct sg_table xfer_buf_sgt;
+	dma_addr_t xfer_buf_dma;
+	void *xfer_buf;
+	u32 len = xfer_buf_len;
+	bool dma_coherent;
+	dma_addr_t xfer_buf_dma_sysdev;
+	int ret;
+
+	dma_coherent = dev_is_dma_coherent(subs->dev->bus->sysdev);
+
+	/* xfer buffer, multiple of 4K only */
+	if (!len)
+		len = PAGE_SIZE;
+
+	len = PAGE_ALIGN(len);
+
+	if (len > MAX_XFER_BUFF_LEN) {
+		dev_err(uaudio_qdev->data->dev,
+			"req buf len %d > max buf len %lu, setting %lu\n",
+			len, MAX_XFER_BUFF_LEN, MAX_XFER_BUFF_LEN);
+		len = MAX_XFER_BUFF_LEN;
+	}
+
+	/* get buffer mapped into subs->dev */
+	xfer_buf = usb_alloc_coherent(subs->dev, len, GFP_KERNEL, &xfer_buf_dma);
+	if (!xfer_buf)
+		return -ENOMEM;
+
+	ret = dma_get_sgtable(subs->dev->bus->sysdev, &xfer_buf_sgt, xfer_buf,
+			      xfer_buf_dma, len);
+	if (ret)
+		goto free_xfer_buf;
+
+	/* map the physical buffer into sysdev as well */
+	xfer_buf_dma_sysdev = uaudio_iommu_map_xfer_buf(dma_coherent,
+							len, &xfer_buf_sgt);
+	if (!xfer_buf_dma_sysdev) {
+		ret = -ENOMEM;
+		goto free_sgt;
+	}
+
+	mem_info->dma = xfer_buf_dma;
+	mem_info->size = len;
+	mem_info->iova = PREPEND_SID_TO_IOVA(xfer_buf_dma_sysdev, uaudio_qdev->data->sid);
+	*xfer_buf_cpu = xfer_buf;
+	sg_free_table(&xfer_buf_sgt);
+
+	return 0;
+
+free_sgt:
+	sg_free_table(&xfer_buf_sgt);
+free_xfer_buf:
+	usb_free_coherent(subs->dev, len, xfer_buf, xfer_buf_dma);
+
+	return ret;
+}
+
+/**
+ * uaudio_endpoint_setup() - fetch and populate endpoint params
+ * @subs: usb substream
+ * @endpoint: usb endpoint to add
+ * @card_num: uadev index
+ * @mem_info: QMI response info
+ * @ep_desc: QMI ep desc response field
+ *
+ * Initialize the USB endpoint being used for a particular USB
+ * stream.  Will request XHCI sec intr to reserve the EP for
+ * offloading as well as populating the QMI response with the
+ * transfer ring parameters.
+ *
+ */
+static phys_addr_t
+uaudio_endpoint_setup(struct snd_usb_substream *subs,
+		      struct snd_usb_endpoint *endpoint, int card_num,
+		      struct mem_info_v01 *mem_info,
+		      struct usb_endpoint_descriptor_v01 *ep_desc)
+{
+	struct usb_host_endpoint *ep;
+	phys_addr_t tr_pa = 0;
+	struct sg_table *sgt;
+	bool dma_coherent;
+	unsigned long iova;
+	struct page *pg;
+	int ret = -ENODEV;
+
+	dma_coherent = dev_is_dma_coherent(subs->dev->bus->sysdev);
+
+	ep = usb_pipe_endpoint(subs->dev, endpoint->pipe);
+	if (!ep) {
+		dev_err(uaudio_qdev->data->dev, "data ep # %d context is null\n",
+			subs->data_endpoint->ep_num);
+		goto exit;
+	}
+
+	memcpy(ep_desc, &ep->desc, sizeof(ep->desc));
+
+	ret = xhci_sideband_add_endpoint(uadev[card_num].sb, ep);
+	if (ret < 0) {
+		dev_err(&subs->dev->dev,
+			"failed to add data ep to sec intr: %d\n", ret);
+		ret = -ENODEV;
+		goto exit;
+	}
+
+	sgt = xhci_sideband_get_endpoint_buffer(uadev[card_num].sb, ep);
+	if (!sgt) {
+		dev_err(&subs->dev->dev,
+			"failed to get data ep ring address: %d\n", ret);
+		ret = -ENODEV;
+		goto remove_ep;
+	}
+
+	pg = sg_page(sgt->sgl);
+	tr_pa = page_to_phys(pg);
+	mem_info->dma = sg_dma_address(sgt->sgl);
+	sg_free_table(sgt);
+	kfree(sgt);
+
+	/* data transfer ring */
+	iova = uaudio_iommu_map_pa(MEM_XFER_RING, dma_coherent, tr_pa,
+				   PAGE_SIZE);
+	if (!iova) {
+		ret = -ENOMEM;
+		goto clear_pa;
+	}
+
+	mem_info->iova = PREPEND_SID_TO_IOVA(iova, uaudio_qdev->data->sid);
+	mem_info->size = PAGE_SIZE;
+
+	return 0;
+
+clear_pa:
+	mem_info->dma = 0;
+remove_ep:
+	xhci_sideband_remove_endpoint(uadev[card_num].sb, ep);
+exit:
+	return ret;
+}
+
+/**
+ * uaudio_event_ring_setup() - fetch and populate event ring params
+ * @subs: usb substream
+ * @card_num: uadev index
+ * @mem_info: QMI response info
+ *
+ * Register secondary interrupter to XHCI and fetch the event buffer info
+ * and populate the information into the QMI response.
+ *
+ */
+static int uaudio_event_ring_setup(struct snd_usb_substream *subs,
+				   int card_num, struct mem_info_v01 *mem_info)
+{
+	struct sg_table *sgt;
+	phys_addr_t er_pa;
+	bool dma_coherent;
+	unsigned long iova;
+	struct page *pg;
+	int ret;
+
+	dma_coherent = dev_is_dma_coherent(subs->dev->bus->sysdev);
+	er_pa = 0;
+
+	ret = usb_offload_get(subs->dev);
+	if (ret < 0)
+		goto exit;
+
+	/* event ring */
+	ret = xhci_sideband_create_interrupter(uadev[card_num].sb, 1, false,
+					       0, uaudio_qdev->data->intr_num);
+	if (ret < 0) {
+		dev_err(&subs->dev->dev, "failed to fetch interrupter\n");
+		goto put_offload;
+	}
+
+	sgt = xhci_sideband_get_event_buffer(uadev[card_num].sb);
+	if (!sgt) {
+		dev_err(&subs->dev->dev,
+			"failed to get event ring address\n");
+		ret = -ENODEV;
+		goto remove_interrupter;
+	}
+
+	pg = sg_page(sgt->sgl);
+	er_pa = page_to_phys(pg);
+	mem_info->dma = sg_dma_address(sgt->sgl);
+	sg_free_table(sgt);
+	kfree(sgt);
+
+	iova = uaudio_iommu_map_pa(MEM_EVENT_RING, dma_coherent, er_pa,
+				   PAGE_SIZE);
+	if (!iova) {
+		ret = -ENOMEM;
+		goto clear_pa;
+	}
+
+	mem_info->iova = PREPEND_SID_TO_IOVA(iova, uaudio_qdev->data->sid);
+	mem_info->size = PAGE_SIZE;
+
+	return 0;
+
+clear_pa:
+	mem_info->dma = 0;
+remove_interrupter:
+	xhci_sideband_remove_interrupter(uadev[card_num].sb);
+put_offload:
+	usb_offload_put(subs->dev);
+exit:
+	return ret;
+}
+
+/**
+ * uaudio_populate_uac_desc() - parse UAC parameters and populate QMI resp
+ * @subs: usb substream
+ * @resp: QMI response buffer
+ *
+ * Parses information specified within UAC descriptors which explain the
+ * sample parameters that the device expects.  This information is populated
+ * to the QMI response sent back to the audio DSP.
+ *
+ */
+static int uaudio_populate_uac_desc(struct snd_usb_substream *subs,
+				    struct qmi_uaudio_stream_resp_msg_v01 *resp)
+{
+	struct usb_interface_descriptor *altsd;
+	struct usb_host_interface *alts;
+	struct usb_interface *iface;
+	int protocol;
+
+	iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
+	if (!iface) {
+		dev_err(&subs->dev->dev, "interface # %d does not exist\n",
+			subs->cur_audiofmt->iface);
+		return -ENODEV;
+	}
+
+	alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
+	altsd = get_iface_desc(alts);
+	protocol = altsd->bInterfaceProtocol;
+
+	if (protocol == UAC_VERSION_1) {
+		struct uac1_as_header_descriptor *as;
+
+		as = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
+					     UAC_AS_GENERAL);
+		if (!as) {
+			dev_err(&subs->dev->dev,
+				"%u:%d : no UAC_AS_GENERAL desc\n",
+				subs->cur_audiofmt->iface,
+				subs->cur_audiofmt->altset_idx);
+			return -ENODEV;
+		}
+
+		resp->data_path_delay = as->bDelay;
+		resp->data_path_delay_valid = 1;
+
+		resp->usb_audio_subslot_size = subs->cur_audiofmt->fmt_sz;
+		resp->usb_audio_subslot_size_valid = 1;
+
+		resp->usb_audio_spec_revision = le16_to_cpu((__force __le16)0x0100);
+		resp->usb_audio_spec_revision_valid = 1;
+	} else if (protocol == UAC_VERSION_2) {
+		resp->usb_audio_subslot_size = subs->cur_audiofmt->fmt_sz;
+		resp->usb_audio_subslot_size_valid = 1;
+
+		resp->usb_audio_spec_revision = le16_to_cpu((__force __le16)0x0200);
+		resp->usb_audio_spec_revision_valid = 1;
+	} else if (protocol == UAC_VERSION_3) {
+		if (iface->intf_assoc->bFunctionSubClass ==
+					UAC3_FUNCTION_SUBCLASS_FULL_ADC_3_0) {
+			dev_err(&subs->dev->dev,
+				"full adc is not supported\n");
+			return -EINVAL;
+		}
+
+		switch (le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize)) {
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_MONO_16:
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_STEREO_16:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_MONO_16:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_STEREO_16: {
+			resp->usb_audio_subslot_size = 0x2;
+			break;
+		}
+
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_MONO_24:
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_STEREO_24:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_MONO_24:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_STEREO_24: {
+			resp->usb_audio_subslot_size = 0x3;
+			break;
+		}
+
+		default:
+			dev_err(&subs->dev->dev,
+				"%d: %u: Invalid wMaxPacketSize\n",
+				subs->cur_audiofmt->iface,
+				subs->cur_audiofmt->altset_idx);
+			return -EINVAL;
+		}
+		resp->usb_audio_subslot_size_valid = 1;
+	} else {
+		dev_err(&subs->dev->dev, "unknown protocol version %x\n",
+			protocol);
+		return -ENODEV;
+	}
+
+	memcpy(&resp->std_as_opr_intf_desc, &alts->desc, sizeof(alts->desc));
+
+	return 0;
+}
+
+/**
+ * prepare_qmi_response() - prepare stream enable response
+ * @subs: usb substream
+ * @req_msg: QMI request message
+ * @resp: QMI response buffer
+ * @info_idx: usb interface array index
+ *
+ * Prepares the QMI response for a USB QMI stream enable request.  Will parse
+ * out the parameters within the stream enable request, in order to match
+ * requested audio profile to the ones exposed by the USB device connected.
+ *
+ * In addition, will fetch the XHCI transfer resources needed for the handoff to
+ * happen.  This includes, transfer ring and buffer addresses and secondary event
+ * ring address.  These parameters will be communicated as part of the USB QMI
+ * stream enable response.
+ *
+ */
+static int prepare_qmi_response(struct snd_usb_substream *subs,
+				struct qmi_uaudio_stream_req_msg_v01 *req_msg,
+				struct qmi_uaudio_stream_resp_msg_v01 *resp,
+				int info_idx)
+{
+	struct q6usb_offload *data;
+	int pcm_dev_num;
+	int card_num;
+	void *xfer_buf_cpu;
+	int ret;
+
+	pcm_dev_num = (req_msg->usb_token & QMI_STREAM_REQ_DEV_NUM_MASK) >> 8;
+	card_num = (req_msg->usb_token & QMI_STREAM_REQ_CARD_NUM_MASK) >> 16;
+
+	if (!uadev[card_num].ctrl_intf) {
+		dev_err(&subs->dev->dev, "audio ctrl intf info not cached\n");
+		return -ENODEV;
+	}
+
+	ret = uaudio_populate_uac_desc(subs, resp);
+	if (ret < 0)
+		return ret;
+
+	resp->slot_id = subs->dev->slot_id;
+	resp->slot_id_valid = 1;
+
+	data = snd_soc_usb_find_priv_data(uaudio_qdev->auxdev->dev.parent);
+	if (!data) {
+		dev_err(&subs->dev->dev, "No private data found\n");
+		return -ENODEV;
+	}
+
+	uaudio_qdev->data = data;
+
+	resp->std_as_opr_intf_desc_valid = 1;
+	ret = uaudio_endpoint_setup(subs, subs->data_endpoint, card_num,
+				    &resp->xhci_mem_info.tr_data,
+				    &resp->std_as_data_ep_desc);
+	if (ret < 0)
+		return ret;
+
+	resp->std_as_data_ep_desc_valid = 1;
+
+	if (subs->sync_endpoint) {
+		ret = uaudio_endpoint_setup(subs, subs->sync_endpoint, card_num,
+					    &resp->xhci_mem_info.tr_sync,
+					    &resp->std_as_sync_ep_desc);
+		if (ret < 0)
+			goto drop_data_ep;
+
+		resp->std_as_sync_ep_desc_valid = 1;
+	}
+
+	resp->interrupter_num_valid = 1;
+	resp->controller_num_valid = 0;
+	ret = usb_get_controller_id(subs->dev);
+	if (ret >= 0) {
+		resp->controller_num = ret;
+		resp->controller_num_valid = 1;
+	}
+
+	/* event ring */
+	ret = uaudio_event_ring_setup(subs, card_num,
+				      &resp->xhci_mem_info.evt_ring);
+	if (ret < 0)
+		goto drop_sync_ep;
+
+	uaudio_qdev->er_mapped = true;
+	resp->interrupter_num = xhci_sideband_interrupter_id(uadev[card_num].sb);
+
+	resp->speed_info = get_speed_info(subs->dev->speed);
+	if (resp->speed_info == USB_QMI_DEVICE_SPEED_INVALID_V01) {
+		ret = -ENODEV;
+		goto free_sec_ring;
+	}
+
+	resp->speed_info_valid = 1;
+
+	ret = uaudio_transfer_buffer_setup(subs, &xfer_buf_cpu, req_msg->xfer_buff_size,
+					   &resp->xhci_mem_info.xfer_buff);
+	if (ret < 0) {
+		ret = -ENOMEM;
+		goto free_sec_ring;
+	}
+
+	resp->xhci_mem_info_valid = 1;
+
+	if (!atomic_read(&uadev[card_num].in_use)) {
+		kref_init(&uadev[card_num].kref);
+		init_waitqueue_head(&uadev[card_num].disconnect_wq);
+		uadev[card_num].num_intf =
+			subs->dev->config->desc.bNumInterfaces;
+		uadev[card_num].info = kzalloc_objs(struct intf_info,
+						    uadev[card_num].num_intf);
+		if (!uadev[card_num].info) {
+			ret = -ENOMEM;
+			goto unmap_er;
+		}
+		uadev[card_num].udev = subs->dev;
+		atomic_set(&uadev[card_num].in_use, 1);
+	} else {
+		kref_get(&uadev[card_num].kref);
+	}
+
+	uadev[card_num].usb_core_id = resp->controller_num;
+
+	/* cache intf specific info to use it for unmap and free xfer buf */
+	uadev[card_num].info[info_idx].data_xfer_ring_va =
+					IOVA_MASK(resp->xhci_mem_info.tr_data.iova);
+	uadev[card_num].info[info_idx].data_xfer_ring_size = PAGE_SIZE;
+	uadev[card_num].info[info_idx].sync_xfer_ring_va =
+					IOVA_MASK(resp->xhci_mem_info.tr_sync.iova);
+	uadev[card_num].info[info_idx].sync_xfer_ring_size = PAGE_SIZE;
+	uadev[card_num].info[info_idx].xfer_buf_iova =
+					IOVA_MASK(resp->xhci_mem_info.xfer_buff.iova);
+	uadev[card_num].info[info_idx].xfer_buf_dma =
+					resp->xhci_mem_info.xfer_buff.dma;
+	uadev[card_num].info[info_idx].xfer_buf_size =
+					resp->xhci_mem_info.xfer_buff.size;
+	uadev[card_num].info[info_idx].data_ep_pipe = subs->data_endpoint ?
+						subs->data_endpoint->pipe : 0;
+	uadev[card_num].info[info_idx].sync_ep_pipe = subs->sync_endpoint ?
+						subs->sync_endpoint->pipe : 0;
+	uadev[card_num].info[info_idx].data_ep_idx = subs->data_endpoint ?
+						subs->data_endpoint->ep_num : 0;
+	uadev[card_num].info[info_idx].sync_ep_idx = subs->sync_endpoint ?
+						subs->sync_endpoint->ep_num : 0;
+	uadev[card_num].info[info_idx].xfer_buf_cpu = xfer_buf_cpu;
+	uadev[card_num].info[info_idx].pcm_card_num = card_num;
+	uadev[card_num].info[info_idx].pcm_dev_num = pcm_dev_num;
+	uadev[card_num].info[info_idx].direction = subs->direction;
+	uadev[card_num].info[info_idx].intf_num = subs->cur_audiofmt->iface;
+	uadev[card_num].info[info_idx].in_use = true;
+
+	set_bit(card_num, &uaudio_qdev->card_slot);
+
+	return 0;
+
+unmap_er:
+	uaudio_iommu_unmap(MEM_EVENT_RING, IOVA_BASE, PAGE_SIZE, PAGE_SIZE);
+free_sec_ring:
+	xhci_sideband_remove_interrupter(uadev[card_num].sb);
+	usb_offload_put(subs->dev);
+drop_sync_ep:
+	if (subs->sync_endpoint) {
+		uaudio_iommu_unmap(MEM_XFER_RING,
+				   IOVA_MASK(resp->xhci_mem_info.tr_sync.iova),
+				   PAGE_SIZE, PAGE_SIZE);
+		xhci_sideband_remove_endpoint(uadev[card_num].sb,
+			usb_pipe_endpoint(subs->dev, subs->sync_endpoint->pipe));
+	}
+drop_data_ep:
+	uaudio_iommu_unmap(MEM_XFER_RING, IOVA_MASK(resp->xhci_mem_info.tr_data.iova),
+			   PAGE_SIZE, PAGE_SIZE);
+	xhci_sideband_remove_endpoint(uadev[card_num].sb,
+			usb_pipe_endpoint(subs->dev, subs->data_endpoint->pipe));
+
+	return ret;
+}
+
+/**
+ * handle_uaudio_stream_req() - handle stream enable/disable request
+ * @handle: QMI client handle
+ * @sq: qrtr socket
+ * @txn: QMI transaction context
+ * @decoded_msg: decoded QMI message
+ *
+ * Main handler for the QMI stream enable/disable requests.  This executes the
+ * corresponding enable/disable stream apis, respectively.
+ *
+ */
+static void handle_uaudio_stream_req(struct qmi_handle *handle,
+				     struct sockaddr_qrtr *sq,
+				     struct qmi_txn *txn,
+				     const void *decoded_msg)
+{
+	struct qmi_uaudio_stream_req_msg_v01 *req_msg;
+	struct qmi_uaudio_stream_resp_msg_v01 resp = {{0}, 0};
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+	struct snd_usb_audio *chip = NULL;
+	struct snd_usb_substream *subs;
+	struct usb_host_endpoint *ep;
+	int datainterval = -EINVAL;
+	int info_idx = -EINVAL;
+	struct intf_info *info;
+	u8 pcm_card_num;
+	u8 pcm_dev_num;
+	u8 direction;
+	int ret = 0;
+
+	if (!svc->client_connected) {
+		svc->client_sq = *sq;
+		svc->client_connected = true;
+	}
+
+	mutex_lock(&qdev_mutex);
+	req_msg = (struct qmi_uaudio_stream_req_msg_v01 *)decoded_msg;
+	if (!req_msg->audio_format_valid || !req_msg->bit_rate_valid ||
+	    !req_msg->number_of_ch_valid || !req_msg->xfer_buff_size_valid) {
+		ret = -EINVAL;
+		goto response;
+	}
+
+	if (!uaudio_qdev) {
+		ret = -EINVAL;
+		goto response;
+	}
+
+	direction = (req_msg->usb_token & QMI_STREAM_REQ_DIRECTION);
+	pcm_dev_num = (req_msg->usb_token & QMI_STREAM_REQ_DEV_NUM_MASK) >> 8;
+	pcm_card_num = (req_msg->usb_token & QMI_STREAM_REQ_CARD_NUM_MASK) >> 16;
+	if (pcm_card_num >= SNDRV_CARDS) {
+		ret = -EINVAL;
+		goto response;
+	}
+
+	if (req_msg->audio_format > USB_QMI_PCM_FORMAT_U32_BE) {
+		ret = -EINVAL;
+		goto response;
+	}
+
+	subs = find_substream(pcm_card_num, pcm_dev_num, direction);
+	chip = uadev[pcm_card_num].chip;
+	if (!subs || !chip || atomic_read(&chip->shutdown)) {
+		ret = -ENODEV;
+		goto response;
+	}
+
+	info_idx = info_idx_from_ifnum(pcm_card_num, subs->cur_audiofmt ?
+			subs->cur_audiofmt->iface : -1, req_msg->enable);
+	if (atomic_read(&chip->shutdown) || !subs->stream || !subs->stream->pcm ||
+	    !subs->stream->chip) {
+		ret = -ENODEV;
+		goto response;
+	}
+
+	scoped_guard(mutex, &chip->mutex) {
+		if (req_msg->enable) {
+			if (info_idx < 0 || chip->system_suspend || subs->opened) {
+				ret = -EBUSY;
+				goto response;
+			}
+			subs->opened = 1;
+		}
+	}
+
+	if (req_msg->service_interval_valid) {
+		ret = get_data_interval_from_si(subs,
+						req_msg->service_interval);
+		if (ret == -EINVAL) {
+			if (req_msg->enable) {
+				guard(mutex)(&chip->mutex);
+				subs->opened = 0;
+			}
+			goto response;
+		}
+
+		datainterval = ret;
+	}
+
+	uadev[pcm_card_num].ctrl_intf = chip->ctrl_intf;
+
+	if (req_msg->enable) {
+		ret = enable_audio_stream(subs,
+					  map_pcm_format(req_msg->audio_format),
+					  req_msg->number_of_ch, req_msg->bit_rate,
+					  datainterval);
+
+		if (!ret)
+			ret = prepare_qmi_response(subs, req_msg, &resp,
+						   info_idx);
+		if (ret < 0) {
+			guard(mutex)(&chip->mutex);
+			subs->opened = 0;
+		}
+	} else {
+		if (info_idx < 0) {
+			ret = -EINVAL;
+			goto response;
+		}
+
+		info = &uadev[pcm_card_num].info[info_idx];
+		if (info->data_ep_pipe) {
+			ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
+					       info->data_ep_pipe);
+			if (ep) {
+				xhci_sideband_stop_endpoint(uadev[pcm_card_num].sb,
+							    ep);
+				xhci_sideband_remove_endpoint(uadev[pcm_card_num].sb,
+							      ep);
+			}
+
+			info->data_ep_pipe = 0;
+		}
+
+		if (info->sync_ep_pipe) {
+			ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
+					       info->sync_ep_pipe);
+			if (ep) {
+				xhci_sideband_stop_endpoint(uadev[pcm_card_num].sb,
+							    ep);
+				xhci_sideband_remove_endpoint(uadev[pcm_card_num].sb,
+							      ep);
+			}
+
+			info->sync_ep_pipe = 0;
+		}
+
+		disable_audio_stream(subs);
+		guard(mutex)(&chip->mutex);
+		subs->opened = 0;
+	}
+
+response:
+	if (!req_msg->enable && ret != -EINVAL && ret != -ENODEV) {
+		guard(mutex)(&chip->mutex);
+		if (info_idx >= 0) {
+			info = &uadev[pcm_card_num].info[info_idx];
+			uaudio_dev_intf_cleanup(uadev[pcm_card_num].udev,
+						info);
+		}
+		if (atomic_read(&uadev[pcm_card_num].in_use))
+			kref_put(&uadev[pcm_card_num].kref,
+				 uaudio_dev_release);
+	}
+	mutex_unlock(&qdev_mutex);
+
+	resp.usb_token = req_msg->usb_token;
+	resp.usb_token_valid = 1;
+	resp.internal_status = ret;
+	resp.internal_status_valid = 1;
+	resp.status = ret ? USB_QMI_STREAM_REQ_FAILURE_V01 : ret;
+	resp.status_valid = 1;
+	ret = qmi_send_response(svc->uaudio_svc_hdl, sq, txn,
+				QMI_UAUDIO_STREAM_RESP_V01,
+				QMI_UAUDIO_STREAM_RESP_MSG_V01_MAX_MSG_LEN,
+				qmi_uaudio_stream_resp_msg_v01_ei, &resp);
+}
+
+static struct qmi_msg_handler uaudio_stream_req_handlers = {
+	.type = QMI_REQUEST,
+	.msg_id = QMI_UAUDIO_STREAM_REQ_V01,
+	.ei = qmi_uaudio_stream_req_msg_v01_ei,
+	.decoded_size = QMI_UAUDIO_STREAM_REQ_MSG_V01_MAX_MSG_LEN,
+	.fn = handle_uaudio_stream_req,
+};
+
+/**
+ * qc_usb_audio_offload_init_qmi_dev() - initializes qmi dev
+ *
+ * Initializes the USB qdev, which is used to carry information pertaining to
+ * the offloading resources.  This device is freed only when there are no longer
+ * any offloading candidates. (i.e, when all audio devices are disconnected)
+ *
+ */
+static int qc_usb_audio_offload_init_qmi_dev(void)
+{
+	uaudio_qdev = kzalloc_obj(*uaudio_qdev);
+	if (!uaudio_qdev)
+		return -ENOMEM;
+
+	/* initialize xfer ring and xfer buf iova list */
+	INIT_LIST_HEAD(&uaudio_qdev->xfer_ring_list);
+	uaudio_qdev->curr_xfer_ring_iova = IOVA_XFER_RING_BASE;
+	uaudio_qdev->xfer_ring_iova_size =
+			IOVA_XFER_RING_MAX - IOVA_XFER_RING_BASE;
+
+	INIT_LIST_HEAD(&uaudio_qdev->xfer_buf_list);
+	uaudio_qdev->curr_xfer_buf_iova = IOVA_XFER_BUF_BASE;
+	uaudio_qdev->xfer_buf_iova_size =
+		IOVA_XFER_BUF_MAX - IOVA_XFER_BUF_BASE;
+
+	return 0;
+}
+
+/* Populates ppcm_idx array with supported PCM indexes */
+static int qc_usb_audio_offload_fill_avail_pcms(struct snd_usb_audio *chip,
+						struct snd_soc_usb_device *sdev)
+{
+	struct snd_usb_stream *as;
+	struct snd_usb_substream *subs;
+	int idx = 0;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		subs = &as->substream[SNDRV_PCM_STREAM_PLAYBACK];
+		if (subs->ep_num) {
+			sdev->ppcm_idx[idx] = as->pcm->device;
+			idx++;
+		}
+		/*
+		 * Break if the current index exceeds the number of possible
+		 * playback streams counted from the UAC descriptors.
+		 */
+		if (idx >= sdev->num_playback)
+			break;
+	}
+
+	return idx;
+}
+
+/**
+ * qc_usb_audio_offload_probe() - platform op connect handler
+ * @chip: USB SND device
+ *
+ * Platform connect handler when a USB SND device is detected. Will
+ * notify SOC USB about the connection to enable the USB ASoC backend
+ * and populate internal USB chip array.
+ *
+ */
+static void qc_usb_audio_offload_probe(struct snd_usb_audio *chip)
+{
+	struct usb_interface *intf = chip->intf[chip->num_interfaces - 1];
+	struct usb_interface_descriptor *altsd;
+	struct usb_host_interface *alts;
+	struct snd_soc_usb_device *sdev;
+	struct xhci_sideband *sb;
+
+	/*
+	 * If there is no priv_data, or no playback paths, the connected
+	 * device doesn't support offloading.  Avoid populating entries for
+	 * this device.
+	 */
+	if (!snd_soc_usb_find_priv_data(uaudio_qdev->auxdev->dev.parent) ||
+	    !usb_qmi_get_pcm_num(chip, 0))
+		return;
+
+	guard(mutex)(&qdev_mutex);
+	guard(mutex)(&chip->mutex);
+	if (!uadev[chip->card->number].chip) {
+		sdev = kzalloc_obj(*sdev);
+		if (!sdev)
+			return;
+
+		sb = xhci_sideband_register(intf, XHCI_SIDEBAND_VENDOR,
+					    uaudio_sideband_notifier);
+		if (!sb)
+			goto free_sdev;
+	} else {
+		sb = uadev[chip->card->number].sb;
+		sdev = uadev[chip->card->number].sdev;
+	}
+
+	uadev[chip->card->number].sb = sb;
+	uadev[chip->card->number].chip = chip;
+	uadev[chip->card->number].sdev = sdev;
+
+	alts = &intf->altsetting[0];
+	altsd = get_iface_desc(alts);
+
+	/* Wait until all PCM devices are populated before notifying soc-usb */
+	if (altsd->bInterfaceNumber == chip->last_iface) {
+		sdev->num_playback = usb_qmi_get_pcm_num(chip, 0);
+
+		/*
+		 * Allocate playback pcm index array based on number of possible
+		 * playback paths within the UAC descriptors.
+		 */
+		sdev->ppcm_idx = kcalloc(sdev->num_playback, sizeof(unsigned int),
+					 GFP_KERNEL);
+		if (!sdev->ppcm_idx)
+			goto unreg_xhci;
+
+		qc_usb_audio_offload_fill_avail_pcms(chip, sdev);
+		sdev->card_idx = chip->card->number;
+		sdev->chip_idx = chip->index;
+
+		snd_usb_offload_create_ctl(chip, uaudio_qdev->auxdev->dev.parent);
+		snd_soc_usb_connect(uaudio_qdev->auxdev->dev.parent, sdev);
+	}
+
+	return;
+
+unreg_xhci:
+	xhci_sideband_unregister(sb);
+	uadev[chip->card->number].sb = NULL;
+free_sdev:
+	kfree(sdev);
+	uadev[chip->card->number].sdev = NULL;
+	uadev[chip->card->number].chip = NULL;
+}
+
+/**
+ * qc_usb_audio_cleanup_qmi_dev() - release qmi device
+ *
+ * Frees the USB qdev.  Only occurs when there are no longer any potential
+ * devices that can utilize USB audio offloading.
+ *
+ */
+static void qc_usb_audio_cleanup_qmi_dev(void)
+{
+	kfree(uaudio_qdev);
+	uaudio_qdev = NULL;
+}
+
+/**
+ * qc_usb_audio_offload_disconnect() - platform op disconnect handler
+ * @chip: USB SND device
+ *
+ * Platform disconnect handler.  Will ensure that any pending stream is
+ * halted by issuing a QMI disconnect indication packet to the adsp.
+ *
+ */
+static void qc_usb_audio_offload_disconnect(struct snd_usb_audio *chip)
+{
+	struct uaudio_dev *dev;
+	int card_num;
+
+	if (!chip)
+		return;
+
+	card_num = chip->card->number;
+	if (card_num >= SNDRV_CARDS)
+		return;
+
+	guard(mutex)(&qdev_mutex);
+	guard(mutex)(&chip->mutex);
+	dev = &uadev[card_num];
+
+	/* Device has already been cleaned up, or never populated */
+	if (!dev->chip)
+		return;
+
+	/* cleaned up already */
+	if (!dev->udev)
+		goto done;
+
+	uaudio_send_disconnect_ind(chip);
+	uaudio_dev_cleanup(dev);
+done:
+	/*
+	 * If num_interfaces == 1, the last USB SND interface is being removed.
+	 * This is to accommodate for devices w/ multiple UAC functions.
+	 */
+	if (chip->num_interfaces == 1) {
+		snd_soc_usb_disconnect(uaudio_qdev->auxdev->dev.parent, dev->sdev);
+		xhci_sideband_unregister(dev->sb);
+		dev->chip = NULL;
+		kfree(dev->sdev->ppcm_idx);
+		kfree(dev->sdev);
+		dev->sdev = NULL;
+	}
+}
+
+/**
+ * qc_usb_audio_offload_suspend() - USB offload PM suspend handler
+ * @intf: USB interface
+ * @message: suspend type
+ *
+ * PM suspend handler to ensure that the USB offloading driver is able to stop
+ * any pending traffic, so that the bus can be suspended.
+ *
+ */
+static void qc_usb_audio_offload_suspend(struct usb_interface *intf,
+					 pm_message_t message)
+{
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
+	int card_num;
+
+	if (!chip)
+		return;
+
+	card_num = chip->card->number;
+	if (card_num >= SNDRV_CARDS)
+		return;
+
+	guard(mutex)(&qdev_mutex);
+	guard(mutex)(&chip->mutex);
+
+	uaudio_send_disconnect_ind(chip);
+}
+
+static struct snd_usb_platform_ops offload_ops = {
+	.connect_cb = qc_usb_audio_offload_probe,
+	.disconnect_cb = qc_usb_audio_offload_disconnect,
+	.suspend_cb = qc_usb_audio_offload_suspend,
+};
+
+static int qc_usb_audio_probe(struct auxiliary_device *auxdev,
+			  const struct auxiliary_device_id *id)
+
+{
+	struct uaudio_qmi_svc *svc;
+	int ret;
+
+	svc = kzalloc_obj(*svc);
+	if (!svc)
+		return -ENOMEM;
+
+	svc->uaudio_svc_hdl = kzalloc_obj(*svc->uaudio_svc_hdl);
+	if (!svc->uaudio_svc_hdl) {
+		ret = -ENOMEM;
+		goto free_svc;
+	}
+
+	ret = qmi_handle_init(svc->uaudio_svc_hdl,
+			      QMI_UAUDIO_STREAM_REQ_MSG_V01_MAX_MSG_LEN,
+			      &uaudio_svc_ops_options,
+			      &uaudio_stream_req_handlers);
+	ret = qmi_add_server(svc->uaudio_svc_hdl, UAUDIO_STREAM_SERVICE_ID_V01,
+			     UAUDIO_STREAM_SERVICE_VERS_V01, 0);
+
+	uaudio_svc = svc;
+
+	qc_usb_audio_offload_init_qmi_dev();
+	uaudio_qdev->auxdev = auxdev;
+
+	ret = snd_usb_register_platform_ops(&offload_ops);
+	if (ret < 0)
+		goto release_qmi;
+
+	snd_usb_rediscover_devices();
+
+	return 0;
+
+release_qmi:
+	qc_usb_audio_cleanup_qmi_dev();
+	qmi_handle_release(svc->uaudio_svc_hdl);
+	kfree(svc->uaudio_svc_hdl);
+free_svc:
+	kfree(svc);
+
+	return ret;
+}
+
+static void qc_usb_audio_remove(struct auxiliary_device *auxdev)
+{
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+	int idx;
+
+	/*
+	 * Remove all connected devices after unregistering ops, to ensure
+	 * that no further connect events will occur.  The disconnect routine
+	 * will issue the QMI disconnect indication, which results in the
+	 * external DSP to stop issuing transfers.
+	 */
+	snd_usb_unregister_platform_ops();
+	for (idx = 0; idx < SNDRV_CARDS; idx++)
+		qc_usb_audio_offload_disconnect(uadev[idx].chip);
+
+	qc_usb_audio_cleanup_qmi_dev();
+
+	qmi_handle_release(svc->uaudio_svc_hdl);
+	kfree(svc->uaudio_svc_hdl);
+	kfree(svc);
+	uaudio_svc = NULL;
+}
+
+static const struct auxiliary_device_id qc_usb_audio_table[] = {
+	{ .name = "q6usb.qc-usb-audio-offload" },
+	{},
+};
+MODULE_DEVICE_TABLE(auxiliary, qc_usb_audio_table);
+
+static struct auxiliary_driver qc_usb_audio_offload_drv = {
+	.name = "qc-usb-audio-offload",
+	.id_table = qc_usb_audio_table,
+	.probe = qc_usb_audio_probe,
+	.remove = qc_usb_audio_remove,
+};
+module_auxiliary_driver(qc_usb_audio_offload_drv);
+
+MODULE_DESCRIPTION("QC USB Audio Offloading");
+MODULE_LICENSE("GPL");
diff --git a/sound/usb/qcom/usb_audio_qmi_v01.c b/sound/usb/qcom/usb_audio_qmi_v01.c
new file mode 100644
index 000000000..502857612
--- /dev/null
+++ b/sound/usb/qcom/usb_audio_qmi_v01.c
@@ -0,0 +1,863 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022-2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/soc/qcom/qmi.h>
+
+#include "usb_audio_qmi_v01.h"
+
+static const struct qmi_elem_info mem_info_v01_ei[] = {
+	{
+		.data_type	= QMI_UNSIGNED_8_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u64),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct mem_info_v01, iova),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_8_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u64),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct mem_info_v01, dma),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct mem_info_v01, size),
+	},
+	{
+		.data_type	= QMI_EOTI,
+		.array_type	= NO_ARRAY,
+		.tlv_type	= QMI_COMMON_TLV_TYPE,
+	},
+};
+
+static const struct qmi_elem_info apps_mem_info_v01_ei[] = {
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct mem_info_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct apps_mem_info_v01, evt_ring),
+		.ei_array	= mem_info_v01_ei,
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct mem_info_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct apps_mem_info_v01, tr_data),
+		.ei_array	= mem_info_v01_ei,
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct mem_info_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct apps_mem_info_v01, tr_sync),
+		.ei_array	= mem_info_v01_ei,
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct mem_info_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct apps_mem_info_v01, xfer_buff),
+		.ei_array	= mem_info_v01_ei,
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct mem_info_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct apps_mem_info_v01, dcba),
+		.ei_array	= mem_info_v01_ei,
+	},
+	{
+		.data_type	= QMI_EOTI,
+		.array_type	= NO_ARRAY,
+		.tlv_type	= QMI_COMMON_TLV_TYPE,
+	},
+};
+
+static const struct qmi_elem_info usb_endpoint_descriptor_v01_ei[] = {
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_endpoint_descriptor_v01,
+						bLength),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_endpoint_descriptor_v01,
+						bDescriptorType),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_endpoint_descriptor_v01,
+						bEndpointAddress),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_endpoint_descriptor_v01,
+						bmAttributes),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_2_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u16),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_endpoint_descriptor_v01,
+						wMaxPacketSize),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_endpoint_descriptor_v01,
+						bInterval),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_endpoint_descriptor_v01,
+						bRefresh),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_endpoint_descriptor_v01,
+						bSynchAddress),
+	},
+	{
+		.data_type	= QMI_EOTI,
+		.array_type	= NO_ARRAY,
+		.tlv_type	= QMI_COMMON_TLV_TYPE,
+	},
+};
+
+static const struct qmi_elem_info usb_interface_descriptor_v01_ei[] = {
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						bLength),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						bDescriptorType),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						bInterfaceNumber),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						bAlternateSetting),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						bNumEndpoints),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						bInterfaceClass),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						bInterfaceSubClass),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						bInterfaceProtocol),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0,
+		.offset		= offsetof(struct usb_interface_descriptor_v01,
+						iInterface),
+	},
+	{
+		.data_type	= QMI_EOTI,
+		.array_type	= NO_ARRAY,
+		.tlv_type	= QMI_COMMON_TLV_TYPE,
+	},
+};
+
+const struct qmi_elem_info qmi_uaudio_stream_req_msg_v01_ei[] = {
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x01,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						enable),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x02,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						usb_token),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x10,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						audio_format_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x10,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						audio_format),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x11,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						number_of_ch_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x11,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						number_of_ch),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x12,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						bit_rate_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x12,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						bit_rate),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x13,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						xfer_buff_size_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x13,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						xfer_buff_size),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x14,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						service_interval_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x14,
+		.offset		= offsetof(struct qmi_uaudio_stream_req_msg_v01,
+						service_interval),
+	},
+	{
+		.data_type	= QMI_EOTI,
+		.array_type	= NO_ARRAY,
+		.tlv_type	= QMI_COMMON_TLV_TYPE,
+	},
+};
+
+const struct qmi_elem_info qmi_uaudio_stream_resp_msg_v01_ei[] = {
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct qmi_response_type_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x02,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					resp),
+		.ei_array	= qmi_response_type_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x10,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					status_valid),
+	},
+	{
+		.data_type	= QMI_SIGNED_4_BYTE_ENUM,
+		.elem_len	= 1,
+		.elem_size	= sizeof(enum usb_qmi_audio_stream_status_enum_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x10,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					status),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x11,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					internal_status_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x11,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					internal_status),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x12,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					slot_id_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x12,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					slot_id),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x13,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					usb_token_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x13,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					usb_token),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x14,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					std_as_opr_intf_desc_valid),
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct usb_interface_descriptor_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x14,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					std_as_opr_intf_desc),
+		.ei_array	= usb_interface_descriptor_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x15,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					std_as_data_ep_desc_valid),
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct usb_endpoint_descriptor_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x15,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					std_as_data_ep_desc),
+		.ei_array	= usb_endpoint_descriptor_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x16,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					std_as_sync_ep_desc_valid),
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct usb_endpoint_descriptor_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x16,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					std_as_sync_ep_desc),
+		.ei_array	= usb_endpoint_descriptor_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x17,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					usb_audio_spec_revision_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_2_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u16),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x17,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					usb_audio_spec_revision),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x18,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					data_path_delay_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x18,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					data_path_delay),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x19,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					usb_audio_subslot_size_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x19,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					usb_audio_subslot_size),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x1A,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					xhci_mem_info_valid),
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct apps_mem_info_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x1A,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					xhci_mem_info),
+		.ei_array	= apps_mem_info_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x1B,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					interrupter_num_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x1B,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					interrupter_num),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x1C,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					speed_info_valid),
+	},
+	{
+		.data_type	= QMI_SIGNED_4_BYTE_ENUM,
+		.elem_len	= 1,
+		.elem_size	= sizeof(enum usb_qmi_audio_device_speed_enum_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x1C,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					speed_info),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x1D,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					controller_num_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x1D,
+		.offset		= offsetof(struct qmi_uaudio_stream_resp_msg_v01,
+					controller_num),
+	},
+	{
+		.data_type	= QMI_EOTI,
+		.array_type	= NO_ARRAY,
+		.tlv_type	= QMI_COMMON_TLV_TYPE,
+	},
+};
+
+const struct qmi_elem_info qmi_uaudio_stream_ind_msg_v01_ei[] = {
+	{
+		.data_type	= QMI_SIGNED_4_BYTE_ENUM,
+		.elem_len	= 1,
+		.elem_size	= sizeof(
+				enum usb_qmi_audio_device_indication_enum_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x01,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						dev_event),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x02,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						slot_id),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x10,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						usb_token_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_4_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u32),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x10,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						usb_token),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x11,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						std_as_opr_intf_desc_valid),
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct usb_interface_descriptor_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x11,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						std_as_opr_intf_desc),
+		.ei_array	= usb_interface_descriptor_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x12,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						std_as_data_ep_desc_valid),
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct usb_endpoint_descriptor_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x12,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						std_as_data_ep_desc),
+		.ei_array	= usb_endpoint_descriptor_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x13,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						std_as_sync_ep_desc_valid),
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct usb_endpoint_descriptor_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x13,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						std_as_sync_ep_desc),
+		.ei_array	= usb_endpoint_descriptor_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x14,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						usb_audio_spec_revision_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_2_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u16),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x14,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						usb_audio_spec_revision),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x15,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						data_path_delay_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x15,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						data_path_delay),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x16,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						usb_audio_subslot_size_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x16,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						usb_audio_subslot_size),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x17,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						xhci_mem_info_valid),
+	},
+	{
+		.data_type	= QMI_STRUCT,
+		.elem_len	= 1,
+		.elem_size	= sizeof(struct apps_mem_info_v01),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x17,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						xhci_mem_info),
+		.ei_array	= apps_mem_info_v01_ei,
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x18,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						interrupter_num_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x18,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						interrupter_num),
+	},
+	{
+		.data_type	= QMI_OPT_FLAG,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x19,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						controller_num_valid),
+	},
+	{
+		.data_type	= QMI_UNSIGNED_1_BYTE,
+		.elem_len	= 1,
+		.elem_size	= sizeof(u8),
+		.array_type	= NO_ARRAY,
+		.tlv_type	= 0x19,
+		.offset		= offsetof(struct qmi_uaudio_stream_ind_msg_v01,
+						controller_num),
+	},
+	{
+		.data_type	= QMI_EOTI,
+		.array_type	= NO_ARRAY,
+		.tlv_type	= QMI_COMMON_TLV_TYPE,
+	},
+};
diff --git a/sound/usb/qcom/usb_audio_qmi_v01.h b/sound/usb/qcom/usb_audio_qmi_v01.h
new file mode 100644
index 000000000..a1298d75d
--- /dev/null
+++ b/sound/usb/qcom/usb_audio_qmi_v01.h
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (c) 2022-2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef USB_QMI_V01_H
+#define USB_QMI_V01_H
+
+#define UAUDIO_STREAM_SERVICE_ID_V01 0x41D
+#define UAUDIO_STREAM_SERVICE_VERS_V01 0x01
+
+#define QMI_UAUDIO_STREAM_RESP_V01 0x0001
+#define QMI_UAUDIO_STREAM_REQ_V01 0x0001
+#define QMI_UAUDIO_STREAM_IND_V01 0x0001
+
+struct mem_info_v01 {
+	u64 iova;	/* mapped into sysdev */
+	u64 dma;	/* mapped into usb host */
+	u32 size;
+};
+
+struct apps_mem_info_v01 {
+	struct mem_info_v01 evt_ring;
+	struct mem_info_v01 tr_data;
+	struct mem_info_v01 tr_sync;
+	struct mem_info_v01 xfer_buff;
+	struct mem_info_v01 dcba;
+};
+
+struct usb_endpoint_descriptor_v01 {
+	u8 bLength;
+	u8 bDescriptorType;
+	u8 bEndpointAddress;
+	u8 bmAttributes;
+	u16 wMaxPacketSize;
+	u8 bInterval;
+	u8 bRefresh;
+	u8 bSynchAddress;
+};
+
+struct usb_interface_descriptor_v01 {
+	u8 bLength;
+	u8 bDescriptorType;
+	u8 bInterfaceNumber;
+	u8 bAlternateSetting;
+	u8 bNumEndpoints;
+	u8 bInterfaceClass;
+	u8 bInterfaceSubClass;
+	u8 bInterfaceProtocol;
+	u8 iInterface;
+};
+
+enum usb_qmi_audio_stream_status_enum_v01 {
+	USB_QMI_STREAM_STATUS_ENUM_MIN_VAL_V01 = INT_MIN,
+	USB_QMI_STREAM_REQ_SUCCESS_V01 = 0,
+	USB_QMI_STREAM_REQ_FAILURE_V01 = 1,
+	USB_QMI_STREAM_REQ_FAILURE_NOT_FOUND_V01 = 2,
+	USB_QMI_STREAM_REQ_FAILURE_INVALID_PARAM_V01 = 3,
+	USB_QMI_STREAM_REQ_FAILURE_MEMALLOC_V01 = 4,
+	USB_QMI_STREAM_STATUS_ENUM_MAX_VAL_V01 = INT_MAX,
+};
+
+enum usb_qmi_audio_device_indication_enum_v01 {
+	USB_QMI_DEVICE_INDICATION_ENUM_MIN_VAL_V01 = INT_MIN,
+	USB_QMI_DEV_CONNECT_V01 = 0,
+	USB_QMI_DEV_DISCONNECT_V01 = 1,
+	USB_QMI_DEV_SUSPEND_V01 = 2,
+	USB_QMI_DEV_RESUME_V01 = 3,
+	USB_QMI_DEVICE_INDICATION_ENUM_MAX_VAL_V01 = INT_MAX,
+};
+
+enum usb_qmi_audio_device_speed_enum_v01 {
+	USB_QMI_DEVICE_SPEED_ENUM_MIN_VAL_V01 = INT_MIN,
+	USB_QMI_DEVICE_SPEED_INVALID_V01 = 0,
+	USB_QMI_DEVICE_SPEED_LOW_V01 = 1,
+	USB_QMI_DEVICE_SPEED_FULL_V01 = 2,
+	USB_QMI_DEVICE_SPEED_HIGH_V01 = 3,
+	USB_QMI_DEVICE_SPEED_SUPER_V01 = 4,
+	USB_QMI_DEVICE_SPEED_SUPER_PLUS_V01 = 5,
+	USB_QMI_DEVICE_SPEED_ENUM_MAX_VAL_V01 = INT_MAX,
+};
+
+struct qmi_uaudio_stream_req_msg_v01 {
+	u8 enable;
+	u32 usb_token;
+	u8 audio_format_valid;
+	u32 audio_format;
+	u8 number_of_ch_valid;
+	u32 number_of_ch;
+	u8 bit_rate_valid;
+	u32 bit_rate;
+	u8 xfer_buff_size_valid;
+	u32 xfer_buff_size;
+	u8 service_interval_valid;
+	u32 service_interval;
+};
+
+#define QMI_UAUDIO_STREAM_REQ_MSG_V01_MAX_MSG_LEN 46
+extern const struct qmi_elem_info qmi_uaudio_stream_req_msg_v01_ei[];
+
+struct qmi_uaudio_stream_resp_msg_v01 {
+	struct qmi_response_type_v01 resp;
+	u8 status_valid;
+	enum usb_qmi_audio_stream_status_enum_v01 status;
+	u8 internal_status_valid;
+	u32 internal_status;
+	u8 slot_id_valid;
+	u32 slot_id;
+	u8 usb_token_valid;
+	u32 usb_token;
+	u8 std_as_opr_intf_desc_valid;
+	struct usb_interface_descriptor_v01 std_as_opr_intf_desc;
+	u8 std_as_data_ep_desc_valid;
+	struct usb_endpoint_descriptor_v01 std_as_data_ep_desc;
+	u8 std_as_sync_ep_desc_valid;
+	struct usb_endpoint_descriptor_v01 std_as_sync_ep_desc;
+	u8 usb_audio_spec_revision_valid;
+	u16 usb_audio_spec_revision;
+	u8 data_path_delay_valid;
+	u8 data_path_delay;
+	u8 usb_audio_subslot_size_valid;
+	u8 usb_audio_subslot_size;
+	u8 xhci_mem_info_valid;
+	struct apps_mem_info_v01 xhci_mem_info;
+	u8 interrupter_num_valid;
+	u8 interrupter_num;
+	u8 speed_info_valid;
+	enum usb_qmi_audio_device_speed_enum_v01 speed_info;
+	u8 controller_num_valid;
+	u8 controller_num;
+};
+
+#define QMI_UAUDIO_STREAM_RESP_MSG_V01_MAX_MSG_LEN 202
+extern const struct qmi_elem_info qmi_uaudio_stream_resp_msg_v01_ei[];
+
+struct qmi_uaudio_stream_ind_msg_v01 {
+	enum usb_qmi_audio_device_indication_enum_v01 dev_event;
+	u32 slot_id;
+	u8 usb_token_valid;
+	u32 usb_token;
+	u8 std_as_opr_intf_desc_valid;
+	struct usb_interface_descriptor_v01 std_as_opr_intf_desc;
+	u8 std_as_data_ep_desc_valid;
+	struct usb_endpoint_descriptor_v01 std_as_data_ep_desc;
+	u8 std_as_sync_ep_desc_valid;
+	struct usb_endpoint_descriptor_v01 std_as_sync_ep_desc;
+	u8 usb_audio_spec_revision_valid;
+	u16 usb_audio_spec_revision;
+	u8 data_path_delay_valid;
+	u8 data_path_delay;
+	u8 usb_audio_subslot_size_valid;
+	u8 usb_audio_subslot_size;
+	u8 xhci_mem_info_valid;
+	struct apps_mem_info_v01 xhci_mem_info;
+	u8 interrupter_num_valid;
+	u8 interrupter_num;
+	u8 controller_num_valid;
+	u8 controller_num;
+};
+
+#define QMI_UAUDIO_STREAM_IND_MSG_V01_MAX_MSG_LEN 181
+extern const struct qmi_elem_info qmi_uaudio_stream_ind_msg_v01_ei[];
+
+#endif
diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
new file mode 100644
index 000000000..dd02c6294
--- /dev/null
+++ b/sound/usb/quirks-table.h
@@ -0,0 +1,4140 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * ALSA USB Audio Driver
+ *
+ * Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>,
+ *                       Clemens Ladisch <clemens@ladisch.de>
+ */
+
+/*
+ * The contents of this file are part of the driver's id_table.
+ *
+ * In a perfect world, this file would be empty.
+ */
+
+/*
+ * Use this for devices where other interfaces are standard compliant,
+ * to prevent the quirk being applied to those interfaces. (To work with
+ * hotplugging, bDeviceClass must be set to USB_CLASS_PER_INTERFACE.)
+ */
+#define USB_DEVICE_VENDOR_SPEC(vend, prod) \
+	.match_flags = USB_DEVICE_ID_MATCH_VENDOR | \
+		       USB_DEVICE_ID_MATCH_PRODUCT | \
+		       USB_DEVICE_ID_MATCH_INT_CLASS, \
+	.idVendor = vend, \
+	.idProduct = prod, \
+	.bInterfaceClass = USB_CLASS_VENDOR_SPEC
+
+/* A standard entry matching with vid/pid and the audio class/subclass */
+#define USB_AUDIO_DEVICE(vend, prod) \
+	.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
+		       USB_DEVICE_ID_MATCH_INT_CLASS | \
+		       USB_DEVICE_ID_MATCH_INT_SUBCLASS, \
+	.idVendor = vend, \
+	.idProduct = prod, \
+	.bInterfaceClass = USB_CLASS_AUDIO, \
+	.bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL
+
+/* Quirk .driver_info, followed by the definition of the quirk entry;
+ * put like QUIRK_DRIVER_INFO { ... } in each entry of the quirk table
+ */
+#define QUIRK_DRIVER_INFO \
+	.driver_info = (unsigned long)&(const struct snd_usb_audio_quirk)
+
+/*
+ * Macros for quirk data entries
+ */
+
+/* Quirk data entry for ignoring the interface */
+#define QUIRK_DATA_IGNORE(_ifno) \
+	.ifnum = (_ifno), .type = QUIRK_IGNORE_INTERFACE
+/* Quirk data entry for a standard audio interface */
+#define QUIRK_DATA_STANDARD_AUDIO(_ifno) \
+	.ifnum = (_ifno), .type = QUIRK_AUDIO_STANDARD_INTERFACE
+/* Quirk data entry for a standard MIDI interface */
+#define QUIRK_DATA_STANDARD_MIDI(_ifno) \
+	.ifnum = (_ifno), .type = QUIRK_MIDI_STANDARD_INTERFACE
+/* Quirk data entry for a standard mixer interface */
+#define QUIRK_DATA_STANDARD_MIXER(_ifno) \
+	.ifnum = (_ifno), .type = QUIRK_AUDIO_STANDARD_MIXER
+
+/* Quirk data entry for Yamaha MIDI */
+#define QUIRK_DATA_MIDI_YAMAHA(_ifno) \
+	.ifnum = (_ifno), .type = QUIRK_MIDI_YAMAHA
+/* Quirk data entry for Edirol UAxx */
+#define QUIRK_DATA_EDIROL_UAXX(_ifno) \
+	.ifnum = (_ifno), .type = QUIRK_AUDIO_EDIROL_UAXX
+/* Quirk data entry for raw bytes interface */
+#define QUIRK_DATA_RAW_BYTES(_ifno) \
+	.ifnum = (_ifno), .type = QUIRK_MIDI_RAW_BYTES
+
+/* Quirk composite array terminator */
+#define QUIRK_COMPOSITE_END	{ .ifnum = -1 }
+
+/* Quirk data entry for composite quirks;
+ * followed by the quirk array that is terminated with QUIRK_COMPOSITE_END
+ * e.g. QUIRK_DATA_COMPOSITE { { quirk1 }, { quirk2 },..., QUIRK_COMPOSITE_END }
+ */
+#define QUIRK_DATA_COMPOSITE \
+	.ifnum = QUIRK_ANY_INTERFACE, \
+	.type = QUIRK_COMPOSITE, \
+	.data = &(const struct snd_usb_audio_quirk[])
+
+/* Quirk data entry for a fixed audio endpoint;
+ * followed by audioformat definition
+ * e.g. QUIRK_DATA_AUDIOFORMAT(n) { .formats = xxx, ... }
+ */
+#define QUIRK_DATA_AUDIOFORMAT(_ifno)	    \
+	.ifnum = (_ifno),		    \
+	.type = QUIRK_AUDIO_FIXED_ENDPOINT, \
+	.data = &(const struct audioformat)
+
+/* Quirk data entry for a fixed MIDI endpoint;
+ * followed by snd_usb_midi_endpoint_info definition
+ * e.g. QUIRK_DATA_MIDI_FIXED_ENDPOINT(n) { .out_cables = x, .in_cables = y }
+ */
+#define QUIRK_DATA_MIDI_FIXED_ENDPOINT(_ifno) \
+	.ifnum = (_ifno),		      \
+	.type = QUIRK_MIDI_FIXED_ENDPOINT,    \
+	.data = &(const struct snd_usb_midi_endpoint_info)
+/* Quirk data entry for a MIDIMAN MIDI endpoint */
+#define QUIRK_DATA_MIDI_MIDIMAN(_ifno) \
+	.ifnum = (_ifno),	       \
+	.type = QUIRK_MIDI_MIDIMAN,    \
+	.data = &(const struct snd_usb_midi_endpoint_info)
+/* Quirk data entry for a EMAGIC MIDI endpoint */
+#define QUIRK_DATA_MIDI_EMAGIC(_ifno) \
+	.ifnum = (_ifno),	      \
+	.type = QUIRK_MIDI_EMAGIC,    \
+	.data = &(const struct snd_usb_midi_endpoint_info)
+
+/*
+ * Here we go... the quirk table definition begins:
+ */
+
+/* FTDI devices */
+{
+	USB_DEVICE(0x0403, 0xb8d8),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "STARR LABS", */
+		/* .product_name = "Starr Labs MIDI USB device", */
+		.ifnum = 0,
+		.type = QUIRK_MIDI_FTDI
+	}
+},
+
+{
+	/* Creative BT-D1 */
+	USB_DEVICE(0x041e, 0x0005),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_AUDIOFORMAT(1) {
+			.formats = SNDRV_PCM_FMTBIT_S16_LE,
+			.channels = 2,
+			.iface = 1,
+			.altsetting = 1,
+			.altset_idx = 1,
+			.endpoint = 0x03,
+			.ep_attr = USB_ENDPOINT_XFER_ISOC,
+			.attributes = 0,
+			.rates = SNDRV_PCM_RATE_CONTINUOUS,
+			.rate_min = 48000,
+			.rate_max = 48000,
+		}
+	}
+},
+
+/* E-Mu 0202 USB */
+{ USB_DEVICE_VENDOR_SPEC(0x041e, 0x3f02) },
+/* E-Mu 0404 USB */
+{ USB_DEVICE_VENDOR_SPEC(0x041e, 0x3f04) },
+/* E-Mu Tracker Pre */
+{ USB_DEVICE_VENDOR_SPEC(0x041e, 0x3f0a) },
+/* E-Mu 0204 USB */
+{ USB_DEVICE_VENDOR_SPEC(0x041e, 0x3f19) },
+/* Ktmicro Usb_audio device */
+{ USB_DEVICE_VENDOR_SPEC(0x31b2, 0x0011) },
+
+/*
+ * Creative Technology, Ltd Live! Cam Sync HD [VF0770]
+ * The device advertises 8 formats, but only a rate of 48kHz is honored by the
+ * hardware and 24 bits give chopped audio, so only report the one working
+ * combination.
+ */
+{
+	USB_AUDIO_DEVICE(0x041e, 0x4095),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(2) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(3) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 2,
+					.fmt_bits = 16,
+					.iface = 3,
+					.altsetting = 4,
+					.altset_idx = 4,
+					.endpoint = 0x82,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 },
+				},
+			},
+			QUIRK_COMPOSITE_END
+		},
+	},
+},
+
+/*
+ * HP Wireless Audio
+ * When not ignored, causes instability issues for some users, forcing them to
+ * skip the entire module.
+ */
+{
+	USB_DEVICE(0x0424, 0xb832),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Standard Microsystems Corp.",
+		.product_name = "HP Wireless Audio",
+		QUIRK_DATA_COMPOSITE {
+			/* Mixer */
+			{ QUIRK_DATA_IGNORE(0) },
+			/* Playback */
+			{ QUIRK_DATA_IGNORE(1) },
+			/* Capture */
+			{ QUIRK_DATA_IGNORE(2) },
+			/* HID Device, .ifnum = 3 */
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/*
+ * Logitech QuickCam: bDeviceClass is vendor-specific, so generic interface
+ * class matches do not take effect without an explicit ID match.
+ */
+{ USB_AUDIO_DEVICE(0x046d, 0x0850) },
+{ USB_AUDIO_DEVICE(0x046d, 0x08ae) },
+{ USB_AUDIO_DEVICE(0x046d, 0x08c6) },
+{ USB_AUDIO_DEVICE(0x046d, 0x08f0) },
+{ USB_AUDIO_DEVICE(0x046d, 0x08f5) },
+{ USB_AUDIO_DEVICE(0x046d, 0x08f6) },
+{ USB_AUDIO_DEVICE(0x046d, 0x0990) },
+
+/*
+ * Yamaha devices
+ */
+
+#define YAMAHA_DEVICE(id, name) { \
+	USB_DEVICE(0x0499, id), \
+	QUIRK_DRIVER_INFO { \
+		.vendor_name = "Yamaha", \
+		.product_name = name, \
+		QUIRK_DATA_MIDI_YAMAHA(QUIRK_ANY_INTERFACE) \
+	} \
+}
+#define YAMAHA_INTERFACE(id, intf, name) { \
+	USB_DEVICE_VENDOR_SPEC(0x0499, id), \
+	QUIRK_DRIVER_INFO { \
+		.vendor_name = "Yamaha", \
+		.product_name = name, \
+		QUIRK_DATA_MIDI_YAMAHA(intf) \
+	} \
+}
+YAMAHA_DEVICE(0x1000, "UX256"),
+YAMAHA_DEVICE(0x1001, "MU1000"),
+YAMAHA_DEVICE(0x1002, "MU2000"),
+YAMAHA_DEVICE(0x1003, "MU500"),
+YAMAHA_INTERFACE(0x1004, 3, "UW500"),
+YAMAHA_DEVICE(0x1005, "MOTIF6"),
+YAMAHA_DEVICE(0x1006, "MOTIF7"),
+YAMAHA_DEVICE(0x1007, "MOTIF8"),
+YAMAHA_DEVICE(0x1008, "UX96"),
+YAMAHA_DEVICE(0x1009, "UX16"),
+YAMAHA_INTERFACE(0x100a, 3, "EOS BX"),
+YAMAHA_DEVICE(0x100c, "UC-MX"),
+YAMAHA_DEVICE(0x100d, "UC-KX"),
+YAMAHA_DEVICE(0x100e, "S08"),
+YAMAHA_DEVICE(0x100f, "CLP-150"),
+YAMAHA_DEVICE(0x1010, "CLP-170"),
+YAMAHA_DEVICE(0x1011, "P-250"),
+YAMAHA_DEVICE(0x1012, "TYROS"),
+YAMAHA_DEVICE(0x1013, "PF-500"),
+YAMAHA_DEVICE(0x1014, "S90"),
+YAMAHA_DEVICE(0x1015, "MOTIF-R"),
+YAMAHA_DEVICE(0x1016, "MDP-5"),
+YAMAHA_DEVICE(0x1017, "CVP-204"),
+YAMAHA_DEVICE(0x1018, "CVP-206"),
+YAMAHA_DEVICE(0x1019, "CVP-208"),
+YAMAHA_DEVICE(0x101a, "CVP-210"),
+YAMAHA_DEVICE(0x101b, "PSR-1100"),
+YAMAHA_DEVICE(0x101c, "PSR-2100"),
+YAMAHA_DEVICE(0x101d, "CLP-175"),
+YAMAHA_DEVICE(0x101e, "PSR-K1"),
+YAMAHA_DEVICE(0x101f, "EZ-J24"),
+YAMAHA_DEVICE(0x1020, "EZ-250i"),
+YAMAHA_DEVICE(0x1021, "MOTIF ES 6"),
+YAMAHA_DEVICE(0x1022, "MOTIF ES 7"),
+YAMAHA_DEVICE(0x1023, "MOTIF ES 8"),
+YAMAHA_DEVICE(0x1024, "CVP-301"),
+YAMAHA_DEVICE(0x1025, "CVP-303"),
+YAMAHA_DEVICE(0x1026, "CVP-305"),
+YAMAHA_DEVICE(0x1027, "CVP-307"),
+YAMAHA_DEVICE(0x1028, "CVP-309"),
+YAMAHA_DEVICE(0x1029, "CVP-309GP"),
+YAMAHA_DEVICE(0x102a, "PSR-1500"),
+YAMAHA_DEVICE(0x102b, "PSR-3000"),
+YAMAHA_DEVICE(0x102e, "ELS-01/01C"),
+YAMAHA_DEVICE(0x1030, "PSR-295/293"),
+YAMAHA_DEVICE(0x1031, "DGX-205/203"),
+YAMAHA_DEVICE(0x1032, "DGX-305"),
+YAMAHA_DEVICE(0x1033, "DGX-505"),
+YAMAHA_DEVICE(0x1034, NULL),
+YAMAHA_DEVICE(0x1035, NULL),
+YAMAHA_DEVICE(0x1036, NULL),
+YAMAHA_DEVICE(0x1037, NULL),
+YAMAHA_DEVICE(0x1038, NULL),
+YAMAHA_DEVICE(0x1039, NULL),
+YAMAHA_DEVICE(0x103a, NULL),
+YAMAHA_DEVICE(0x103b, NULL),
+YAMAHA_DEVICE(0x103c, NULL),
+YAMAHA_DEVICE(0x103d, NULL),
+YAMAHA_DEVICE(0x103e, NULL),
+YAMAHA_DEVICE(0x103f, NULL),
+YAMAHA_DEVICE(0x1040, NULL),
+YAMAHA_DEVICE(0x1041, NULL),
+YAMAHA_DEVICE(0x1042, NULL),
+YAMAHA_DEVICE(0x1043, NULL),
+YAMAHA_DEVICE(0x1044, NULL),
+YAMAHA_DEVICE(0x1045, NULL),
+YAMAHA_INTERFACE(0x104e, 0, NULL),
+YAMAHA_DEVICE(0x104f, NULL),
+YAMAHA_DEVICE(0x1050, NULL),
+YAMAHA_DEVICE(0x1051, NULL),
+YAMAHA_DEVICE(0x1052, NULL),
+YAMAHA_INTERFACE(0x1053, 0, NULL),
+YAMAHA_INTERFACE(0x1054, 0, NULL),
+YAMAHA_DEVICE(0x1055, NULL),
+YAMAHA_DEVICE(0x1056, NULL),
+YAMAHA_DEVICE(0x1057, NULL),
+YAMAHA_DEVICE(0x1058, NULL),
+YAMAHA_DEVICE(0x1059, NULL),
+YAMAHA_DEVICE(0x105a, NULL),
+YAMAHA_DEVICE(0x105b, NULL),
+YAMAHA_DEVICE(0x105c, NULL),
+YAMAHA_DEVICE(0x105d, NULL),
+{
+	USB_DEVICE(0x0499, 0x1503),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Yamaha", */
+		/* .product_name = "MOX6/MOX8", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_MIDI_YAMAHA(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0499, 0x1507),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Yamaha", */
+		/* .product_name = "THR10", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_MIDI_YAMAHA(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0499, 0x1509),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Yamaha", */
+		/* .product_name = "Steinberg UR22", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_MIDI_YAMAHA(3) },
+			{ QUIRK_DATA_IGNORE(4) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0499, 0x150a),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Yamaha", */
+		/* .product_name = "THR5A", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_MIDI_YAMAHA(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0499, 0x150c),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Yamaha", */
+		/* .product_name = "THR10C", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_MIDI_YAMAHA(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0499, 0x150d),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Yamaha", */
+		/* .product_name = "CDS3000", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_MIDI_YAMAHA(3) },
+			{ QUIRK_DATA_IGNORE(4) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0499, 0x1718),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Yamaha", */
+		/* .product_name = "P-125", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_MIDI_YAMAHA(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+YAMAHA_DEVICE(0x2000, "DGP-7"),
+YAMAHA_DEVICE(0x2001, "DGP-5"),
+YAMAHA_DEVICE(0x2002, NULL),
+YAMAHA_DEVICE(0x2003, NULL),
+YAMAHA_DEVICE(0x5000, "CS1D"),
+YAMAHA_DEVICE(0x5001, "DSP1D"),
+YAMAHA_DEVICE(0x5002, "DME32"),
+YAMAHA_DEVICE(0x5003, "DM2000"),
+YAMAHA_DEVICE(0x5004, "02R96"),
+YAMAHA_DEVICE(0x5005, "ACU16-C"),
+YAMAHA_DEVICE(0x5006, "NHB32-C"),
+YAMAHA_DEVICE(0x5007, "DM1000"),
+YAMAHA_DEVICE(0x5008, "01V96"),
+YAMAHA_DEVICE(0x5009, "SPX2000"),
+YAMAHA_DEVICE(0x500a, "PM5D"),
+YAMAHA_DEVICE(0x500b, "DME64N"),
+YAMAHA_DEVICE(0x500c, "DME24N"),
+YAMAHA_DEVICE(0x500d, NULL),
+YAMAHA_DEVICE(0x500e, NULL),
+YAMAHA_DEVICE(0x500f, NULL),
+YAMAHA_DEVICE(0x7000, "DTX"),
+YAMAHA_DEVICE(0x7010, "UB99"),
+#undef YAMAHA_DEVICE
+#undef YAMAHA_INTERFACE
+/* this catches most recent vendor-specific Yamaha devices */
+{
+	.match_flags = USB_DEVICE_ID_MATCH_VENDOR |
+	               USB_DEVICE_ID_MATCH_INT_CLASS,
+	.idVendor = 0x0499,
+	.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
+	QUIRK_DRIVER_INFO {
+		.ifnum = QUIRK_ANY_INTERFACE,
+		.type = QUIRK_AUTODETECT
+	}
+},
+
+/*
+ * Roland/RolandED/Edirol/BOSS devices
+ */
+{
+	USB_DEVICE(0x0582, 0x0000),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "UA-100",
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 4,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x01,
+					.ep_attr = 0x09,
+					.rates = SNDRV_PCM_RATE_CONTINUOUS,
+					.rate_min = 44100,
+					.rate_max = 44100,
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 2,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_FILL_MAX,
+					.endpoint = 0x81,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_CONTINUOUS,
+					.rate_min = 44100,
+					.rate_max = 44100,
+				}
+			},
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0007,
+					.in_cables  = 0x0007
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x0002),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UM-4",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x000f,
+					.in_cables  = 0x000f
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x0003),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "SC-8850",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x003f,
+					.in_cables  = 0x003f
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x0004),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "U-8",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0005,
+					.in_cables  = 0x0005
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* Has ID 0x0099 when not in "Advanced Driver" mode.
+	 * The UM-2EX has only one input, but we cannot detect this. */
+	USB_DEVICE(0x0582, 0x0005),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UM-2",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0003,
+					.in_cables  = 0x0003
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x0007),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "SC-8820",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0013,
+					.in_cables  = 0x0013
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x0008),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "PC-300",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x009d when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0009),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UM-1",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x000b),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "SK-500",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0013,
+					.in_cables  = 0x0013
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* thanks to Emiliano Grilli <emillo@libero.it>
+	 * for helping researching this data */
+	USB_DEVICE(0x0582, 0x000c),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "SC-D70",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0007,
+					.in_cables  = 0x0007
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{	/*
+	 * This quirk is for the "Advanced Driver" mode of the Edirol UA-5.
+	 * If the advanced mode switch at the back of the unit is off, the
+	 * UA-5 has ID 0x0582/0x0011 and is standard compliant (no quirks),
+	 * but offers only 16-bit PCM.
+	 * In advanced mode, the UA-5 will output S24_3LE samples (two
+	 * channels) at the rate indicated on the front switch, including
+	 * the 96kHz sample rate.
+	 */
+	USB_DEVICE(0x0582, 0x0010),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UA-5",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x0013 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0012),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "XV-5050",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/* has ID 0x0015 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0014),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UM-880",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x01ff,
+			.in_cables  = 0x01ff
+		}
+	}
+},
+{
+	/* has ID 0x0017 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0016),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "SD-90",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x000f,
+					.in_cables  = 0x000f
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x001c when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x001b),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "MMP-2",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x001e when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x001d),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "V-SYNTH",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/* has ID 0x0024 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0023),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UM-550",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x003f,
+			.in_cables  = 0x003f
+		}
+	}
+},
+{
+	/*
+	 * This quirk is for the "Advanced Driver" mode. If off, the UA-20
+	 * has ID 0x0026 and is standard compliant, but has only 16-bit PCM
+	 * and no MIDI.
+	 */
+	USB_DEVICE(0x0582, 0x0025),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UA-20",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 2,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x01,
+					.ep_attr = 0x01,
+					.rates = SNDRV_PCM_RATE_CONTINUOUS,
+					.rate_min = 44100,
+					.rate_max = 44100,
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 2,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x82,
+					.ep_attr = 0x01,
+					.rates = SNDRV_PCM_RATE_CONTINUOUS,
+					.rate_min = 44100,
+					.rate_max = 44100,
+				}
+			},
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(3) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x0028 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0027),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "SD-20",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0003,
+			.in_cables  = 0x0007
+		}
+	}
+},
+{
+	/* has ID 0x002a when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0029),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "SD-80",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x000f,
+			.in_cables  = 0x000f
+		}
+	}
+},
+{	/*
+	 * This quirk is for the "Advanced" modes of the Edirol UA-700.
+	 * If the sample format switch is not in an advanced setting, the
+	 * UA-700 has ID 0x0582/0x002c and is standard compliant (no quirks),
+	 * but offers only 16-bit PCM and no MIDI.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x0582, 0x002b),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UA-700",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_EDIROL_UAXX(1) },
+			{ QUIRK_DATA_EDIROL_UAXX(2) },
+			{ QUIRK_DATA_EDIROL_UAXX(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x002e when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x002d),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "XV-2020",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/* has ID 0x0030 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x002f),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "VariOS",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0007,
+			.in_cables  = 0x0007
+		}
+	}
+},
+{
+	/* has ID 0x0034 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0033),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "PCR",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0003,
+			.in_cables  = 0x0007
+		}
+	}
+},
+{
+	/*
+	 * Has ID 0x0038 when not in "Advanced Driver" mode;
+	 * later revisions use IDs 0x0054 and 0x00a2.
+	 */
+	USB_DEVICE(0x0582, 0x0037),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "Digital Piano",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/*
+	 * This quirk is for the "Advanced Driver" mode.  If off, the GS-10
+	 * has ID 0x003c and is standard compliant, but has only 16-bit PCM
+	 * and no MIDI.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x0582, 0x003b),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "BOSS",
+		.product_name = "GS-10",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_STANDARD_MIDI(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x0041 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0040),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "GI-20",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/* has ID 0x0043 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0042),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "RS-70",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/* has ID 0x0049 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0047),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "EDIROL", */
+		/* .product_name = "UR-80", */
+		QUIRK_DATA_COMPOSITE {
+			/* in the 96 kHz modes, only interface 1 is there */
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x004a when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0048),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "EDIROL", */
+		/* .product_name = "UR-80", */
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0003,
+			.in_cables  = 0x0007
+		}
+	}
+},
+{
+	/* has ID 0x004e when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x004c),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "PCR-A",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x004f when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x004d),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "PCR-A",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0003,
+			.in_cables  = 0x0007
+		}
+	}
+},
+{
+	/*
+	 * This quirk is for the "Advanced Driver" mode. If off, the UA-3FX
+	 * is standard compliant, but has only 16-bit PCM.
+	 */
+	USB_DEVICE(0x0582, 0x0050),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UA-3FX",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x0052),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UM-1SX",
+		QUIRK_DATA_STANDARD_MIDI(0)
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x0060),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "EXR Series",
+		QUIRK_DATA_STANDARD_MIDI(0)
+	}
+},
+{
+	/* has ID 0x0066 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0064),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "EDIROL", */
+		/* .product_name = "PCR-1", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x0067 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0065),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "EDIROL", */
+		/* .product_name = "PCR-1", */
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0003
+		}
+	}
+},
+{
+	/* has ID 0x006e when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x006d),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "FANTOM-X",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{	/*
+	 * This quirk is for the "Advanced" modes of the Edirol UA-25.
+	 * If the switch is not in an advanced setting, the UA-25 has
+	 * ID 0x0582/0x0073 and is standard compliant (no quirks), but
+	 * offers only 16-bit PCM at 44.1 kHz and no MIDI.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x0582, 0x0074),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UA-25",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_EDIROL_UAXX(0) },
+			{ QUIRK_DATA_EDIROL_UAXX(1) },
+			{ QUIRK_DATA_EDIROL_UAXX(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* has ID 0x0076 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0075),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "BOSS",
+		.product_name = "DR-880",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/* has ID 0x007b when not in "Advanced Driver" mode */
+	USB_DEVICE_VENDOR_SPEC(0x0582, 0x007a),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		/* "RD" or "RD-700SX"? */
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0003,
+			.in_cables  = 0x0003
+		}
+	}
+},
+{
+	/* has ID 0x0081 when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x0080),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Roland",
+		.product_name = "G-70",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/* has ID 0x008c when not in "Advanced Driver" mode */
+	USB_DEVICE(0x0582, 0x008b),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "PC-50",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	/*
+	 * This quirk is for the "Advanced Driver" mode. If off, the UA-4FX
+	 * is standard compliant, but has only 16-bit PCM and no MIDI.
+	 */
+	USB_DEVICE(0x0582, 0x00a3),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UA-4FX",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_EDIROL_UAXX(0) },
+			{ QUIRK_DATA_EDIROL_UAXX(1) },
+			{ QUIRK_DATA_EDIROL_UAXX(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* Edirol M-16DX */
+	USB_DEVICE(0x0582, 0x00c4),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* Advanced modes of the Edirol UA-25EX.
+	 * For the standard mode, UA-25EX has ID 0582:00e7, which
+	 * offers only 16-bit PCM at 44.1 kHz and no MIDI.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x0582, 0x00e6),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "EDIROL",
+		.product_name = "UA-25EX",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_EDIROL_UAXX(0) },
+			{ QUIRK_DATA_EDIROL_UAXX(1) },
+			{ QUIRK_DATA_EDIROL_UAXX(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* Edirol UM-3G */
+	USB_DEVICE_VENDOR_SPEC(0x0582, 0x0108),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(0) {
+			.out_cables = 0x0007,
+			.in_cables  = 0x0007
+		}
+	}
+},
+{
+	/* BOSS ME-25 */
+	USB_DEVICE(0x0582, 0x0113),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* only 44.1 kHz works at the moment */
+	USB_DEVICE(0x0582, 0x0120),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Roland", */
+		/* .product_name = "OCTO-CAPTURE", */
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 10,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x05,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 12,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x85,
+					.ep_attr = 0x25,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			{ QUIRK_DATA_IGNORE(3) },
+			{ QUIRK_DATA_IGNORE(4) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* only 44.1 kHz works at the moment */
+	USB_DEVICE(0x0582, 0x012f),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Roland", */
+		/* .product_name = "QUAD-CAPTURE", */
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 4,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x05,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 6,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x85,
+					.ep_attr = 0x25,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			{ QUIRK_DATA_IGNORE(3) },
+			{ QUIRK_DATA_IGNORE(4) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0582, 0x0159),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Roland", */
+		/* .product_name = "UA-22", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(2) {
+					.out_cables = 0x0001,
+					.in_cables = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* UA101 and co are supported by another driver */
+{
+	USB_DEVICE(0x0582, 0x0044), /* UA-1000 high speed */
+	QUIRK_DRIVER_INFO {
+		.ifnum = QUIRK_NODEV_INTERFACE
+	},
+},
+{
+	USB_DEVICE(0x0582, 0x007d), /* UA-101 high speed */
+	QUIRK_DRIVER_INFO {
+		.ifnum = QUIRK_NODEV_INTERFACE
+	},
+},
+{
+	USB_DEVICE(0x0582, 0x008d), /* UA-101 full speed */
+	QUIRK_DRIVER_INFO {
+		.ifnum = QUIRK_NODEV_INTERFACE
+	},
+},
+
+/* this catches most recent vendor-specific Roland devices */
+{
+	.match_flags = USB_DEVICE_ID_MATCH_VENDOR |
+	               USB_DEVICE_ID_MATCH_INT_CLASS,
+	.idVendor = 0x0582,
+	.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
+	QUIRK_DRIVER_INFO {
+		.ifnum = QUIRK_ANY_INTERFACE,
+		.type = QUIRK_AUTODETECT
+	}
+},
+
+/* Guillemot devices */
+{
+	/*
+	 * This is for the "Windows Edition" where the external MIDI ports are
+	 * the only MIDI ports; the control data is reported through HID
+	 * interfaces.  The "Macintosh Edition" has ID 0xd002 and uses standard
+	 * compliant USB MIDI ports for external MIDI and controls.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x06f8, 0xb000),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Hercules",
+		.product_name = "DJ Console (WE)",
+		QUIRK_DATA_MIDI_FIXED_ENDPOINT(4) {
+			.out_cables = 0x0001,
+			.in_cables = 0x0001
+		}
+	}
+},
+
+/* Midiman/M-Audio devices */
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x1002),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "MidiSport 2x2",
+		QUIRK_DATA_MIDI_MIDIMAN(QUIRK_ANY_INTERFACE) {
+			.out_cables = 0x0003,
+			.in_cables  = 0x0003
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x1011),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "MidiSport 1x1",
+		QUIRK_DATA_MIDI_MIDIMAN(QUIRK_ANY_INTERFACE) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x1015),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "Keystation",
+		QUIRK_DATA_MIDI_MIDIMAN(QUIRK_ANY_INTERFACE) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x1021),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "MidiSport 4x4",
+		QUIRK_DATA_MIDI_MIDIMAN(QUIRK_ANY_INTERFACE) {
+			.out_cables = 0x000f,
+			.in_cables  = 0x000f
+		}
+	}
+},
+{
+	/*
+	 * For hardware revision 1.05; in the later revisions (1.10 and
+	 * 1.21), 0x1031 is the ID for the device without firmware.
+	 * Thanks to Olaf Giesbrecht <Olaf_Giesbrecht@yahoo.de>
+	 */
+	USB_DEVICE_VER(0x0763, 0x1031, 0x0100, 0x0109),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "MidiSport 8x8",
+		QUIRK_DATA_MIDI_MIDIMAN(QUIRK_ANY_INTERFACE) {
+			.out_cables = 0x01ff,
+			.in_cables  = 0x01ff
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x1033),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "MidiSport 8x8",
+		QUIRK_DATA_MIDI_MIDIMAN(QUIRK_ANY_INTERFACE) {
+			.out_cables = 0x01ff,
+			.in_cables  = 0x01ff
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x1041),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "MidiSport 2x4",
+		QUIRK_DATA_MIDI_MIDIMAN(QUIRK_ANY_INTERFACE) {
+			.out_cables = 0x000f,
+			.in_cables  = 0x0003
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2001),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "Quattro",
+		QUIRK_DATA_COMPOSITE {
+			/*
+			 * Interfaces 0-2 are "Windows-compatible", 16-bit only,
+			 * and share endpoints with the other interfaces.
+			 * Ignore them.  The other interfaces can do 24 bits,
+			 * but captured samples are big-endian (see usbaudio.c).
+			 */
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{ QUIRK_DATA_IGNORE(2) },
+			{ QUIRK_DATA_IGNORE(3) },
+			{ QUIRK_DATA_STANDARD_AUDIO(4) },
+			{ QUIRK_DATA_STANDARD_AUDIO(5) },
+			{ QUIRK_DATA_IGNORE(6) },
+			{ QUIRK_DATA_STANDARD_AUDIO(7) },
+			{ QUIRK_DATA_STANDARD_AUDIO(8) },
+			{
+				QUIRK_DATA_MIDI_MIDIMAN(9) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2003),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "AudioPhile",
+		QUIRK_DATA_MIDI_MIDIMAN(6) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2008),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "Ozone",
+		QUIRK_DATA_MIDI_MIDIMAN(3) {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x200d),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "OmniStudio",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{ QUIRK_DATA_IGNORE(2) },
+			{ QUIRK_DATA_IGNORE(3) },
+			{ QUIRK_DATA_STANDARD_AUDIO(4) },
+			{ QUIRK_DATA_STANDARD_AUDIO(5) },
+			{ QUIRK_DATA_IGNORE(6) },
+			{ QUIRK_DATA_STANDARD_AUDIO(7) },
+			{ QUIRK_DATA_STANDARD_AUDIO(8) },
+			{
+				QUIRK_DATA_MIDI_MIDIMAN(9) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x0763, 0x2019),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "M-Audio", */
+		/* .product_name = "Ozone Academic", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{
+				QUIRK_DATA_MIDI_MIDIMAN(3) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* M-Audio Micro */
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x201a),
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2030),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "M-Audio", */
+		/* .product_name = "Fast Track C400", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(1) },
+			/* Playback */
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 6,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x01,
+					.ep_attr = 0x09,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+							44100, 48000, 88200, 96000
+					},
+					.clock = 0x80,
+				}
+			},
+			/* Capture */
+			{
+				QUIRK_DATA_AUDIOFORMAT(3) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 4,
+					.iface = 3,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x81,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 88200, 96000
+					},
+					.clock = 0x80,
+				}
+			},
+			/* MIDI: Interface = 4*/
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2031),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "M-Audio", */
+		/* .product_name = "Fast Track C600", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(1) },
+			/* Playback */
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x01,
+					.ep_attr = 0x09,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+							44100, 48000, 88200, 96000
+					},
+					.clock = 0x80,
+				}
+			},
+			/* Capture */
+			{
+				QUIRK_DATA_AUDIOFORMAT(3) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 6,
+					.iface = 3,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x81,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 88200, 96000
+					},
+					.clock = 0x80,
+				}
+			},
+			/* MIDI: Interface = 4 */
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2080),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "M-Audio", */
+		/* .product_name = "Fast Track Ultra", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x01,
+					.ep_attr = 0x09,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 88200, 96000
+					}
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x81,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 88200, 96000
+					}
+				}
+			},
+			/* interface 3 (MIDI) is standard compliant */
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2081),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "M-Audio", */
+		/* .product_name = "Fast Track Ultra 8R", */
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x01,
+					.ep_attr = 0x09,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+							44100, 48000, 88200, 96000
+					}
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x81,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 88200, 96000
+					}
+				}
+			},
+			/* interface 3 (MIDI) is standard compliant */
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * M-Audio Venom
+	 *
+	 * The AudioControl interface times out on every GET_CUR request,
+	 * which adds around 47 seconds to the card registration and
+	 * freezes the device, blocking streaming.
+	 * Using an explicit composite quirk to skip the mixer entirely.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2084),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "Venom",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_STANDARD_MIDI(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* Casio devices */
+{
+	USB_DEVICE(0x07cf, 0x6801),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Casio",
+		.product_name = "PL-40R",
+		QUIRK_DATA_MIDI_YAMAHA(0)
+	}
+},
+{
+	/* this ID is used by several devices without a product ID */
+	USB_DEVICE(0x07cf, 0x6802),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Casio",
+		.product_name = "Keyboard",
+		QUIRK_DATA_MIDI_YAMAHA(0)
+	}
+},
+
+/* Mark of the Unicorn devices */
+{
+	/* thanks to Robert A. Lerche <ral 'at' msbit.com> */
+	.match_flags = USB_DEVICE_ID_MATCH_VENDOR |
+		       USB_DEVICE_ID_MATCH_PRODUCT |
+		       USB_DEVICE_ID_MATCH_DEV_SUBCLASS,
+	.idVendor = 0x07fd,
+	.idProduct = 0x0001,
+	.bDeviceSubClass = 2,
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "MOTU",
+		.product_name = "Fastlane",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_RAW_BYTES(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* Emagic devices */
+{
+	USB_DEVICE(0x086a, 0x0001),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Emagic",
+		.product_name = "Unitor8",
+		QUIRK_DATA_MIDI_EMAGIC(2) {
+			.out_cables = 0x80ff,
+			.in_cables  = 0x80ff
+		}
+	}
+},
+{
+	USB_DEVICE(0x086a, 0x0002),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Emagic",
+		/* .product_name = "AMT8", */
+		QUIRK_DATA_MIDI_EMAGIC(2) {
+			.out_cables = 0x80ff,
+			.in_cables  = 0x80ff
+		}
+	}
+},
+{
+	USB_DEVICE(0x086a, 0x0003),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Emagic",
+		/* .product_name = "MT4", */
+		QUIRK_DATA_MIDI_EMAGIC(2) {
+			.out_cables = 0x800f,
+			.in_cables  = 0x8003
+		}
+	}
+},
+
+/* KORG devices */
+{
+	USB_DEVICE_VENDOR_SPEC(0x0944, 0x0200),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "KORG, Inc.",
+		/* .product_name = "PANDORA PX5D", */
+		QUIRK_DATA_STANDARD_MIDI(3)
+	}
+},
+
+{
+	USB_DEVICE_VENDOR_SPEC(0x0944, 0x0201),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "KORG, Inc.",
+		/* .product_name = "ToneLab ST", */
+		QUIRK_DATA_STANDARD_MIDI(3)
+	}
+},
+
+{
+	USB_DEVICE_VENDOR_SPEC(0x0944, 0x0204),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "KORG, Inc.",
+		/* .product_name = "ToneLab EX", */
+		QUIRK_DATA_STANDARD_MIDI(3)
+	}
+},
+
+/* AKAI devices */
+{
+	USB_DEVICE(0x09e8, 0x0062),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "AKAI",
+		.product_name = "MPD16",
+		.ifnum = 0,
+		.type = QUIRK_MIDI_AKAI,
+	}
+},
+
+{
+	/* Akai MPC Element */
+	USB_DEVICE(0x09e8, 0x0021),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_STANDARD_MIDI(1) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* Steinberg devices */
+{
+	/* Steinberg MI2 */
+	USB_DEVICE_VENDOR_SPEC(0x0a4e, 0x2040),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(3) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* Steinberg MI4 */
+	USB_DEVICE_VENDOR_SPEC(0x0a4e, 0x4040),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(3) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* TerraTec devices */
+{
+	USB_DEVICE_VENDOR_SPEC(0x0ccd, 0x0012),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "TerraTec",
+		.product_name = "PHASE 26",
+		QUIRK_DATA_STANDARD_MIDI(3)
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0ccd, 0x0013),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "TerraTec",
+		.product_name = "PHASE 26",
+		QUIRK_DATA_STANDARD_MIDI(3)
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x0ccd, 0x0014),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "TerraTec",
+		.product_name = "PHASE 26",
+		QUIRK_DATA_STANDARD_MIDI(3)
+	}
+},
+{
+	USB_DEVICE(0x0ccd, 0x0035),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Miditech",
+		.product_name = "Play'n Roll",
+		.ifnum = 0,
+		.type = QUIRK_MIDI_CME
+	}
+},
+
+/* Stanton ScratchAmp */
+{ USB_DEVICE(0x103d, 0x0100) },
+{ USB_DEVICE(0x103d, 0x0101) },
+
+/* Novation EMS devices */
+{
+	USB_DEVICE_VENDOR_SPEC(0x1235, 0x0001),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Novation",
+		.product_name = "ReMOTE Audio/XStation",
+		.ifnum = 4,
+		.type = QUIRK_MIDI_NOVATION
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x1235, 0x0002),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Novation",
+		.product_name = "Speedio",
+		.ifnum = 3,
+		.type = QUIRK_MIDI_NOVATION
+	}
+},
+{
+	USB_DEVICE(0x1235, 0x000a),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Novation", */
+		/* .product_name = "Nocturn", */
+		QUIRK_DATA_RAW_BYTES(0)
+	}
+},
+{
+	USB_DEVICE(0x1235, 0x000e),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Novation", */
+		/* .product_name = "Launchpad", */
+		QUIRK_DATA_RAW_BYTES(0)
+	}
+},
+{
+	USB_DEVICE(0x1235, 0x0010),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Focusrite",
+		.product_name = "Saffire 6 USB",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 4,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC,
+					.datainterval = 1,
+					.maxpacksize = 0x024c,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000,
+					.rate_min = 44100,
+					.rate_max = 48000,
+					.nr_rates = 2,
+					.rate_table = (unsigned int[]) {
+						44100, 48000
+					},
+					.sync_ep = 0x82,
+					.sync_iface = 0,
+					.sync_altsetting = 1,
+					.sync_ep_idx = 1,
+					.implicit_fb = 1,
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 2,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC,
+					.datainterval = 1,
+					.maxpacksize = 0x0126,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000,
+					.rate_min = 44100,
+					.rate_max = 48000,
+					.nr_rates = 2,
+					.rate_table = (unsigned int[]) {
+						44100, 48000
+					}
+				}
+			},
+			{ QUIRK_DATA_RAW_BYTES(1) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x1235, 0x0018),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Novation",
+		.product_name = "Twitch",
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 4,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000,
+					.rate_min = 44100,
+					.rate_max = 48000,
+					.nr_rates = 2,
+					.rate_table = (unsigned int[]) {
+						44100, 48000
+					}
+				}
+			},
+			{ QUIRK_DATA_RAW_BYTES(1) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	USB_DEVICE(0x1235, 0x001e),
+	QUIRK_DRIVER_INFO {
+		/* .vendor_name = "Novation", */
+		/* .product_name = "Mininova", */
+		QUIRK_DATA_RAW_BYTES(0)
+	}
+},
+{
+	USB_DEVICE_VENDOR_SPEC(0x1235, 0x4661),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Novation",
+		.product_name = "ReMOTE25",
+		.ifnum = 0,
+		.type = QUIRK_MIDI_NOVATION
+	}
+},
+
+/* Access Music devices */
+{
+	/* VirusTI Desktop */
+	USB_DEVICE_VENDOR_SPEC(0x133e, 0x0815),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(3) {
+					.out_cables = 0x0003,
+					.in_cables  = 0x0003
+				}
+			},
+			{ QUIRK_DATA_IGNORE(4) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* Native Instruments MK2 series */
+{
+	/* Komplete Audio 6 */
+	.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
+	.idVendor = 0x17cc,
+	.idProduct = 0x1000,
+},
+{
+	/* Traktor Audio 6 */
+	.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
+	.idVendor = 0x17cc,
+	.idProduct = 0x1010,
+},
+{
+	/* Traktor Audio 10 */
+	.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
+	.idVendor = 0x17cc,
+	.idProduct = 0x1020,
+},
+
+/* QinHeng devices */
+{
+	USB_DEVICE(0x1a86, 0x752d),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "QinHeng",
+		.product_name = "CH345",
+		.ifnum = 1,
+		.type = QUIRK_MIDI_CH345
+	}
+},
+
+/* KeithMcMillen Stringport */
+{ USB_DEVICE(0x1f38, 0x0001) }, /* FIXME: should be more restrictive matching */
+
+/* Miditech devices */
+{
+	USB_DEVICE(0x4752, 0x0011),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Miditech",
+		.product_name = "Midistart-2",
+		.ifnum = 0,
+		.type = QUIRK_MIDI_CME
+	}
+},
+
+/* Central Music devices */
+{
+	/* this ID used by both Miditech MidiStudio-2 and CME UF-x */
+	USB_DEVICE(0x7104, 0x2202),
+	QUIRK_DRIVER_INFO {
+		.ifnum = 0,
+		.type = QUIRK_MIDI_CME
+	}
+},
+
+/* Digidesign Mbox */
+{
+	/* Thanks to Clemens Ladisch <clemens@ladisch.de> */
+	USB_DEVICE(0x0dba, 0x1000),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Digidesign",
+		.product_name = "MBox",
+		QUIRK_DATA_COMPOSITE{
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3BE,
+					.channels = 2,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0x4,
+					.endpoint = 0x02,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_SYNC,
+					.maxpacksize = 0x130,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3BE,
+					.channels = 2,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0x4,
+					.endpoint = 0x81,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_ASYNC,
+					.maxpacksize = 0x130,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* DIGIDESIGN MBOX 2 */
+{
+	USB_DEVICE(0x0dba, 0x3000),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Digidesign",
+		.product_name = "Mbox 2",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3BE,
+					.channels = 2,
+					.iface = 2,
+					.altsetting = 2,
+					.altset_idx = 1,
+					.attributes = 0x00,
+					.endpoint = 0x03,
+					.ep_attr = USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			{ QUIRK_DATA_IGNORE(3) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(4) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3BE,
+					.channels = 2,
+					.iface = 4,
+					.altsetting = 2,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x85,
+					.ep_attr = USB_ENDPOINT_SYNC_SYNC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			{ QUIRK_DATA_IGNORE(5) },
+			{
+				QUIRK_DATA_MIDI_MIDIMAN(6) {
+					.out_ep =  0x02,
+					.out_cables = 0x0001,
+					.in_ep = 0x81,
+					.in_interval = 0x01,
+					.in_cables = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+/* DIGIDESIGN MBOX 3 */
+{
+	USB_DEVICE(0x0dba, 0x5000),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Digidesign",
+		.product_name = "Mbox 3",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_IGNORE(1) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.fmt_bits = 24,
+					.channels = 4,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0x00,
+					.endpoint = USB_RECIP_INTERFACE | USB_DIR_OUT,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |
+							SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 88200, 96000
+					},
+					.sync_ep = USB_RECIP_INTERFACE | USB_DIR_IN,
+					.sync_iface = 3,
+					.sync_altsetting = 1,
+					.sync_ep_idx = 1,
+					.implicit_fb = 1,
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(3) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.fmt_bits = 24,
+					.channels = 4,
+					.iface = 3,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0x00,
+					.endpoint = USB_RECIP_INTERFACE | USB_DIR_IN,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_ASYNC,
+					.maxpacksize = 0x009c,
+					.rates = SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |
+							SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 88200, 96000
+					},
+					.implicit_fb = 0,
+				}
+			},
+			{
+				QUIRK_DATA_MIDI_FIXED_ENDPOINT(4) {
+					.out_cables = 0x0001,
+					.in_cables  = 0x0001
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* Tascam US122 MKII - playback-only support */
+	USB_DEVICE_VENDOR_SPEC(0x0644, 0x8021),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "TASCAM",
+		.product_name = "US122 MKII",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 2,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x02,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_88200 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 4,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 88200, 96000
+					}
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* Denon DN-X1600 */
+{
+	USB_AUDIO_DEVICE(0x154e, 0x500e),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Denon",
+		.product_name = "DN-X1600",
+		QUIRK_DATA_COMPOSITE{
+			{ QUIRK_DATA_IGNORE(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0x0,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_ADAPTIVE,
+					.maxpacksize = 0x138,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0x0,
+					.endpoint = 0x85,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_ADAPTIVE,
+					.maxpacksize = 0x138,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			{ QUIRK_DATA_STANDARD_MIDI(4) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* Microsoft XboxLive Headset/Xbox Communicator */
+{
+	USB_DEVICE(0x045e, 0x0283),
+	.bInterfaceClass = USB_CLASS_PER_INTERFACE,
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Microsoft",
+		.product_name = "XboxLive Headset/Xbox Communicator",
+		QUIRK_DATA_COMPOSITE {
+			{
+				/* playback */
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 1,
+					.iface = 0,
+					.altsetting = 0,
+					.altset_idx = 0,
+					.attributes = 0,
+					.endpoint = 0x04,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_CONTINUOUS,
+					.rate_min = 22050,
+					.rate_max = 22050
+				}
+			},
+			{
+				/* capture */
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 1,
+					.iface = 1,
+					.altsetting = 0,
+					.altset_idx = 0,
+					.attributes = 0,
+					.endpoint = 0x85,
+					.ep_attr = 0x05,
+					.rates = SNDRV_PCM_RATE_CONTINUOUS,
+					.rate_min = 16000,
+					.rate_max = 16000
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/* Reloop Play */
+{
+	USB_DEVICE(0x200c, 0x100b),
+	.bInterfaceClass = USB_CLASS_PER_INTERFACE,
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 4,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_SYNC_ADAPTIVE,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000,
+					.rate_min = 44100,
+					.rate_max = 48000,
+					.nr_rates = 2,
+					.rate_table = (unsigned int[]) {
+						44100, 48000
+					}
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+{
+	/*
+	 * ZOOM R16/24 in audio interface mode.
+	 * Playback requires an extra four byte LE length indicator
+	 * at the start of each isochronous packet. This quirk is
+	 * enabled in create_standard_audio_quirk().
+	 */
+	USB_DEVICE(0x1686, 0x00dd),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(1) }, /* Playback  */
+			{ QUIRK_DATA_STANDARD_AUDIO(2) }, /* Capture */
+			{ QUIRK_DATA_STANDARD_MIDI(3) }, /* Midi */
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+{
+	/*
+	 * Some USB MIDI devices don't have an audio control interface,
+	 * so we have to grab MIDI streaming interfaces here.
+	 */
+	.match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
+		       USB_DEVICE_ID_MATCH_INT_SUBCLASS,
+	.bInterfaceClass = USB_CLASS_AUDIO,
+	.bInterfaceSubClass = USB_SUBCLASS_MIDISTREAMING,
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_STANDARD_MIDI(QUIRK_ANY_INTERFACE)
+	}
+},
+
+/* Rane SL-1 */
+{
+	USB_DEVICE(0x13e5, 0x0001),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_STANDARD_AUDIO(QUIRK_ANY_INTERFACE)
+        }
+},
+
+/* disabled due to regression for other devices;
+ * see https://bugzilla.kernel.org/show_bug.cgi?id=199905
+ */
+#if 0
+{
+	/*
+	 * Nura's first gen headphones use Cambridge Silicon Radio's vendor
+	 * ID, but it looks like the product ID actually is only for Nura.
+	 * The capture interface does not work at all (even on Windows),
+	 * and only the 48 kHz sample rate works for the playback interface.
+	 */
+	USB_DEVICE(0x0a12, 0x1243),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			{ QUIRK_DATA_IGNORE(1) }, /* Capture */
+			/* Playback */
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 2,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_FILL_MAX |
+						UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x03,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+#endif /* disabled */
+
+{
+	/*
+	 * The AudioBox USB advertises S24_3LE as the only supported format
+	 * for both playback and capture. It does not support S16_LE despite
+	 * being a USB full-speed device.
+	 */
+	USB_DEVICE(0x194f, 0x0301),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "PreSonus",
+		.product_name = "AudioBox USB",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.fmt_bits = 24,
+					.channels = 2,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000,
+					.rate_min = 44100,
+					.rate_max = 48000,
+					.nr_rates = 2,
+					.rate_table = (unsigned int[]) {
+						44100, 48000
+					},
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(3) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.fmt_bits = 24,
+					.channels = 2,
+					.iface = 3,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x82,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC,
+					.rates = SNDRV_PCM_RATE_44100 |
+						 SNDRV_PCM_RATE_48000,
+					.rate_min = 44100,
+					.rate_max = 48000,
+					.nr_rates = 2,
+					.rate_table = (unsigned int[]) {
+						44100, 48000
+					},
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+{
+	/*
+	 * Bower's & Wilkins PX headphones only support the 48 kHz sample rate
+	 * even though it advertises more. The capture interface doesn't work
+	 * even on windows.
+	 */
+	USB_DEVICE(0x19b5, 0x0021),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			/* Playback */
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 2,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = UAC_EP_CS_ATTR_FILL_MAX |
+						UAC_EP_CS_ATTR_SAMPLE_RATE,
+					.endpoint = 0x03,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+/* MOTU Microbook II */
+{
+	USB_DEVICE_VENDOR_SPEC(0x07fd, 0x0004),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "MOTU",
+		.product_name = "MicroBookII",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3BE,
+					.channels = 6,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x84,
+					.rates = SNDRV_PCM_RATE_96000,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rate_min = 96000,
+					.rate_max = 96000,
+					.nr_rates = 1,
+					.maxpacksize = 0x00d8,
+					.rate_table = (unsigned int[]) {
+						96000
+					}
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3BE,
+					.channels = 8,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x03,
+					.ep_idx = 1,
+					.rates = SNDRV_PCM_RATE_96000,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rate_min = 96000,
+					.rate_max = 96000,
+					.nr_rates = 1,
+					.maxpacksize = 0x0120,
+					.rate_table = (unsigned int[]) {
+						96000
+					}
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * PIONEER DJ DDJ-SX3
+	 * PCM is 12 channels out, 10 channels in @ 44.1 fixed
+	 * interface 0, vendor class alt setting 1 for endpoints 5 and 0x86
+	 * The feedback for the output is the input.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x0023),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 12,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x05,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 10,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x86,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						 USB_ENDPOINT_SYNC_ASYNC|
+						 USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Pioneer DJ DJM-250MK2
+	 * PCM is 8 channels out @ 48 fixed (endpoint 0x01)
+	 * and 8 channels in @ 48 fixed (endpoint 0x82).
+	 *
+	 * Both playback and recording is working, even simultaneously.
+	 *
+	 * Playback channels could be mapped to:
+	 *  - CH1
+	 *  - CH2
+	 *  - AUX
+	 *
+	 * Recording channels could be mapped to:
+	 *  - Post CH1 Fader
+	 *  - Post CH2 Fader
+	 *  - Cross Fader A
+	 *  - Cross Fader B
+	 *  - MIC
+	 *  - AUX
+	 *  - REC OUT
+	 *
+	 * There is remaining problem with recording directly from PHONO/LINE.
+	 * If we map a channel to:
+	 *  - CH1 Control Tone PHONO
+	 *  - CH1 Control Tone LINE
+	 *  - CH2 Control Tone PHONO
+	 *  - CH2 Control Tone LINE
+	 * it is silent.
+	 * There is no signal even on other operating systems with official drivers.
+	 * The signal appears only when a supported application is started.
+	 * This needs to be investigated yet...
+	 * (there is quite a lot communication on the USB in both directions)
+	 *
+	 * In current version this mixer could be used for playback
+	 * and for recording from vinyls (through Post CH* Fader)
+	 * but not for DVS (Digital Vinyl Systems) like in Mixxx.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x0017),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8, // outputs
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 }
+					}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8, // inputs
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC|
+						USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * PIONEER DJ DDJ-RB
+	 * PCM is 4 channels out, 2 dummy channels in @ 44.1 fixed
+	 * The feedback for the output is the dummy input.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x000e),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 4,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 2,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						 USB_ENDPOINT_SYNC_ASYNC|
+						 USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+{
+	/*
+	 * PIONEER DJ DDJ-RR
+	 * PCM is 6 channels out & 4 channels in @ 44.1 fixed
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x000d),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 6, //Master, Headphones & Booth
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 4, //2x RCA inputs (CH1 & CH2)
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						 USB_ENDPOINT_SYNC_ASYNC|
+						 USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+{
+	/*
+	 * PIONEER DJ DDJ-SR2
+	 * PCM is 4 channels out, 6 channels in @ 44.1 fixed
+	 * The Feedback for the output is the input
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x001e),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 4,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 6,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC|
+					USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+{
+	/*
+	 * Pioneer DJ DJM-900NXS2
+	 * 10 channels playback & 12 channels capture @ 44.1/48/96kHz S24LE
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x000a),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 10,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+					    USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100|
+					    SNDRV_PCM_RATE_48000|
+					    SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 96000
+					}
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 12,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+					    USB_ENDPOINT_SYNC_ASYNC|
+					    USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100|
+					    SNDRV_PCM_RATE_48000|
+					    SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 96000
+					}
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+{
+	/*
+	 * PIONEER DJ DDJ-800
+	 * PCM is 6 channels out, 6 channels in @ 44.1 fixed
+	 * The Feedback for the output is the input
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x0029),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 6,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 6,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC|
+					USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100,
+					.rate_min = 44100,
+					.rate_max = 44100,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 44100 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+{
+	/*
+	 * Pioneer DJ / AlphaTheta DJM-A9
+	 * 10 channels playback & 12 channels capture @ 44.1/48/96kHz S24LE
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x003c),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 10,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+					    USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100|
+					    SNDRV_PCM_RATE_48000|
+					    SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 96000
+					}
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 12,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+					    USB_ENDPOINT_SYNC_ASYNC|
+					    USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100|
+					    SNDRV_PCM_RATE_48000|
+					    SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) {
+						44100, 48000, 96000
+					}
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Pioneer DJ DJM-V10
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x0034),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 12, // outputs
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100|
+					    SNDRV_PCM_RATE_48000|
+					    SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) { 44100, 48000, 96000 }
+					}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 12,  // inputs
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC|
+						USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100|
+					    SNDRV_PCM_RATE_48000|
+					    SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) { 44100, 48000, 96000 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Pioneer DJ / AlphaTheta DJM-S11
+	 */
+	USB_DEVICE(0x2b73, 0x0037),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_STANDARD_MIXER(0)
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 14,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 },
+					.clock = 1,
+					.fmt_type = UAC_FORMAT_TYPE_I
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 10,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC |
+						   USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 },
+					.clock = 1,
+					.fmt_type = UAC_FORMAT_TYPE_I
+				}
+			},
+			{
+				/* Audio Control (unknown purpose) */
+				.ifnum = 3,
+				.type = QUIRK_IGNORE_INTERFACE
+			},
+			{
+				.ifnum = 4,
+				.type = QUIRK_MIDI_STANDARD_INTERFACE
+			},
+			{
+				/* HID */
+				.ifnum = 5,
+				.type = QUIRK_IGNORE_INTERFACE
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/*
+ * MacroSilicon MS2100/MS2106 based AV capture cards
+ *
+ * These claim 96kHz 1ch in the descriptors, but are actually 48kHz 2ch.
+ * They also need QUIRK_FLAG_ALIGN_TRANSFER, which makes one wonder if
+ * they pretend to be 96kHz mono as a workaround for stereo being broken
+ * by that...
+ *
+ * They also have an issue with initial stream alignment that causes the
+ * channels to be swapped and out of phase, which is dealt with in quirks.c.
+ */
+{
+	USB_AUDIO_DEVICE(0x534d, 0x0021),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "MacroSilicon",
+		.product_name = "MS210x",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(2) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(3) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 2,
+					.iface = 3,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x82,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_CONTINUOUS,
+					.rate_min = 48000,
+					.rate_max = 48000,
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+/*
+ * MacroSilicon MS2109 based HDMI capture cards
+ *
+ * These claim 96kHz 1ch in the descriptors, but are actually 48kHz 2ch.
+ * They also need QUIRK_FLAG_ALIGN_TRANSFER, which makes one wonder if
+ * they pretend to be 96kHz mono as a workaround for stereo being broken
+ * by that...
+ *
+ * They also have an issue with initial stream alignment that causes the
+ * channels to be swapped and out of phase, which is dealt with in quirks.c.
+ */
+{
+	USB_AUDIO_DEVICE(0x534d, 0x2109),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "MacroSilicon",
+		.product_name = "MS2109",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(2) },
+			{
+				QUIRK_DATA_AUDIOFORMAT(3) {
+					.formats = SNDRV_PCM_FMTBIT_S16_LE,
+					.channels = 2,
+					.iface = 3,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.attributes = 0,
+					.endpoint = 0x82,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_CONTINUOUS,
+					.rate_min = 48000,
+					.rate_max = 48000,
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Pioneer DJ DJM-750
+	 * 8 channels playback & 8 channels capture @ 44.1/48/96kHz S24LE
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x08e4, 0x017f),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x05,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+					    USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_44100|
+						SNDRV_PCM_RATE_48000|
+						SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) { 44100, 48000, 96000 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x86,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC|
+						USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_44100|
+						SNDRV_PCM_RATE_48000|
+						SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) { 44100, 48000, 96000 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Pioneer DJ DJM-750MK2
+	 * 10 channels playback & 12 channels capture @ 48kHz S24LE
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x001b),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 10,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+					    USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) {
+						48000
+					}
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 12,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC|
+						USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Pioneer DJ DJM-850
+	 * 8 channels playback and 8 channels capture @ 44.1/48/96kHz S24LE
+	 * Playback on EP 0x05
+	 * Capture on EP 0x86
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x08e4, 0x0163),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x05,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+					    USB_ENDPOINT_SYNC_ASYNC|
+						USB_ENDPOINT_USAGE_DATA,
+					.rates = SNDRV_PCM_RATE_44100|
+						SNDRV_PCM_RATE_48000|
+						SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) { 44100, 48000, 96000 }
+				}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8,
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x86,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC|
+						USB_ENDPOINT_USAGE_DATA,
+					.rates = SNDRV_PCM_RATE_44100|
+						SNDRV_PCM_RATE_48000|
+						SNDRV_PCM_RATE_96000,
+					.rate_min = 44100,
+					.rate_max = 96000,
+					.nr_rates = 3,
+					.rate_table = (unsigned int[]) { 44100, 48000, 96000 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Pioneer DJ DJM-450
+	 * PCM is 8 channels out @ 48 fixed (endpoint 0x01)
+	 * and 8 channels in @ 48 fixed (endpoint 0x82).
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x2b73, 0x0013),
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8, // outputs
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 }
+					}
+			},
+			{
+				QUIRK_DATA_AUDIOFORMAT(0) {
+					.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+					.channels = 8, // inputs
+					.iface = 0,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_idx = 1,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC|
+						USB_ENDPOINT_SYNC_ASYNC|
+						USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 }
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Sennheiser GSP670
+	 * Change order of interfaces loaded
+	 */
+	USB_DEVICE(0x1395, 0x0300),
+	.bInterfaceClass = USB_CLASS_PER_INTERFACE,
+	QUIRK_DRIVER_INFO {
+		QUIRK_DATA_COMPOSITE {
+			// Communication
+			{ QUIRK_DATA_STANDARD_AUDIO(3) },
+			// Recording
+			{ QUIRK_DATA_STANDARD_AUDIO(4) },
+			// Main
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Fiero SC-01 (firmware v1.0.0 @ 48 kHz)
+	 */
+	USB_DEVICE(0x2b53, 0x0023),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Fiero",
+		.product_name = "SC-01",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			/* Playback */
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 2,
+					.fmt_bits = 24,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 },
+					.clock = 0x29
+				}
+			},
+			/* Capture */
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 2,
+					.fmt_bits = 24,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC |
+						   USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_48000,
+					.rate_min = 48000,
+					.rate_max = 48000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 48000 },
+					.clock = 0x29
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Fiero SC-01 (firmware v1.0.0 @ 96 kHz)
+	 */
+	USB_DEVICE(0x2b53, 0x0024),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Fiero",
+		.product_name = "SC-01",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			/* Playback */
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 2,
+					.fmt_bits = 24,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_96000,
+					.rate_min = 96000,
+					.rate_max = 96000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 96000 },
+					.clock = 0x29
+				}
+			},
+			/* Capture */
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 2,
+					.fmt_bits = 24,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC |
+						   USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_96000,
+					.rate_min = 96000,
+					.rate_max = 96000,
+					.nr_rates = 1,
+					.rate_table = (unsigned int[]) { 96000 },
+					.clock = 0x29
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/*
+	 * Fiero SC-01 (firmware v1.1.0)
+	 */
+	USB_DEVICE(0x2b53, 0x0031),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Fiero",
+		.product_name = "SC-01",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_AUDIO(0) },
+			/* Playback */
+			{
+				QUIRK_DATA_AUDIOFORMAT(1) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 2,
+					.fmt_bits = 24,
+					.iface = 1,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x01,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC,
+					.rates = SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 48000,
+					.rate_max = 96000,
+					.nr_rates = 2,
+					.rate_table = (unsigned int[]) { 48000, 96000 },
+					.clock = 0x29
+				}
+			},
+			/* Capture */
+			{
+				QUIRK_DATA_AUDIOFORMAT(2) {
+					.formats = SNDRV_PCM_FMTBIT_S32_LE,
+					.channels = 2,
+					.fmt_bits = 24,
+					.iface = 2,
+					.altsetting = 1,
+					.altset_idx = 1,
+					.endpoint = 0x82,
+					.ep_attr = USB_ENDPOINT_XFER_ISOC |
+						   USB_ENDPOINT_SYNC_ASYNC |
+						   USB_ENDPOINT_USAGE_IMPLICIT_FB,
+					.rates = SNDRV_PCM_RATE_48000 |
+						 SNDRV_PCM_RATE_96000,
+					.rate_min = 48000,
+					.rate_max = 96000,
+					.nr_rates = 2,
+					.rate_table = (unsigned int[]) { 48000, 96000 },
+					.clock = 0x29
+				}
+			},
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+{
+	/* Advanced modes of the Mythware XA001AU.
+	 * For the standard mode, Mythware XA001AU has ID ffad:a001
+	 */
+	USB_DEVICE_VENDOR_SPEC(0xffad, 0xa001),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Mythware",
+		.product_name = "XA001AU",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+#define QUIRK_RME_DIGIFACE(pid) \
+{ \
+	/* Only claim interface 0 */ \
+	.match_flags = USB_DEVICE_ID_MATCH_VENDOR | \
+		       USB_DEVICE_ID_MATCH_PRODUCT | \
+		       USB_DEVICE_ID_MATCH_INT_CLASS | \
+		       USB_DEVICE_ID_MATCH_INT_NUMBER, \
+	.idVendor = 0x2a39, \
+	.idProduct = pid, \
+	.bInterfaceClass = USB_CLASS_VENDOR_SPEC, \
+	.bInterfaceNumber = 0, \
+	QUIRK_DRIVER_INFO { \
+		QUIRK_DATA_COMPOSITE { \
+			/*
+			 * Three modes depending on sample rate band,
+			 * with different channel counts for in/out
+			 */ \
+			{ QUIRK_DATA_STANDARD_MIXER(0) }, \
+			{ \
+				QUIRK_DATA_AUDIOFORMAT(0) { \
+					.formats = SNDRV_PCM_FMTBIT_S32_LE, \
+					.channels = 34, /* outputs */ \
+					.fmt_bits = 24, \
+					.iface = 0, \
+					.altsetting = 1, \
+					.altset_idx = 1, \
+					.endpoint = 0x02, \
+					.ep_idx = 1, \
+					.ep_attr = USB_ENDPOINT_XFER_ISOC | \
+						USB_ENDPOINT_SYNC_ASYNC, \
+					.rates = SNDRV_PCM_RATE_32000 | \
+						SNDRV_PCM_RATE_44100 | \
+						SNDRV_PCM_RATE_48000, \
+					.rate_min = 32000, \
+					.rate_max = 48000, \
+					.nr_rates = 3, \
+					.rate_table = (unsigned int[]) { \
+						32000, 44100, 48000, \
+					}, \
+					.sync_ep = 0x81, \
+					.sync_iface = 0, \
+					.sync_altsetting = 1, \
+					.sync_ep_idx = 0, \
+					.implicit_fb = 1, \
+				}, \
+			}, \
+			{ \
+				QUIRK_DATA_AUDIOFORMAT(0) { \
+					.formats = SNDRV_PCM_FMTBIT_S32_LE, \
+					.channels = 18, /* outputs */ \
+					.fmt_bits = 24, \
+					.iface = 0, \
+					.altsetting = 1, \
+					.altset_idx = 1, \
+					.endpoint = 0x02, \
+					.ep_idx = 1, \
+					.ep_attr = USB_ENDPOINT_XFER_ISOC | \
+						USB_ENDPOINT_SYNC_ASYNC, \
+					.rates = SNDRV_PCM_RATE_64000 | \
+						SNDRV_PCM_RATE_88200 | \
+						SNDRV_PCM_RATE_96000, \
+					.rate_min = 64000, \
+					.rate_max = 96000, \
+					.nr_rates = 3, \
+					.rate_table = (unsigned int[]) { \
+						64000, 88200, 96000, \
+					}, \
+					.sync_ep = 0x81, \
+					.sync_iface = 0, \
+					.sync_altsetting = 1, \
+					.sync_ep_idx = 0, \
+					.implicit_fb = 1, \
+				}, \
+			}, \
+			{ \
+				QUIRK_DATA_AUDIOFORMAT(0) { \
+					.formats = SNDRV_PCM_FMTBIT_S32_LE, \
+					.channels = 10, /* outputs */ \
+					.fmt_bits = 24, \
+					.iface = 0, \
+					.altsetting = 1, \
+					.altset_idx = 1, \
+					.endpoint = 0x02, \
+					.ep_idx = 1, \
+					.ep_attr = USB_ENDPOINT_XFER_ISOC | \
+						USB_ENDPOINT_SYNC_ASYNC, \
+					.rates = SNDRV_PCM_RATE_KNOT | \
+						SNDRV_PCM_RATE_176400 | \
+						SNDRV_PCM_RATE_192000, \
+					.rate_min = 128000, \
+					.rate_max = 192000, \
+					.nr_rates = 3, \
+					.rate_table = (unsigned int[]) { \
+						128000, 176400, 192000, \
+					}, \
+					.sync_ep = 0x81, \
+					.sync_iface = 0, \
+					.sync_altsetting = 1, \
+					.sync_ep_idx = 0, \
+					.implicit_fb = 1, \
+				}, \
+			}, \
+			{ \
+				QUIRK_DATA_AUDIOFORMAT(0) { \
+					.formats = SNDRV_PCM_FMTBIT_S32_LE, \
+					.channels = 32, /* inputs */ \
+					.fmt_bits = 24, \
+					.iface = 0, \
+					.altsetting = 1, \
+					.altset_idx = 1, \
+					.endpoint = 0x81, \
+					.ep_attr = USB_ENDPOINT_XFER_ISOC | \
+						USB_ENDPOINT_SYNC_ASYNC, \
+					.rates = SNDRV_PCM_RATE_32000 | \
+						SNDRV_PCM_RATE_44100 | \
+						SNDRV_PCM_RATE_48000, \
+					.rate_min = 32000, \
+					.rate_max = 48000, \
+					.nr_rates = 3, \
+					.rate_table = (unsigned int[]) { \
+						32000, 44100, 48000, \
+					} \
+				} \
+			}, \
+			{ \
+				QUIRK_DATA_AUDIOFORMAT(0) { \
+					.formats = SNDRV_PCM_FMTBIT_S32_LE, \
+					.channels = 16, /* inputs */ \
+					.fmt_bits = 24, \
+					.iface = 0, \
+					.altsetting = 1, \
+					.altset_idx = 1, \
+					.endpoint = 0x81, \
+					.ep_attr = USB_ENDPOINT_XFER_ISOC | \
+						USB_ENDPOINT_SYNC_ASYNC, \
+					.rates = SNDRV_PCM_RATE_64000 | \
+						SNDRV_PCM_RATE_88200 | \
+						SNDRV_PCM_RATE_96000, \
+					.rate_min = 64000, \
+					.rate_max = 96000, \
+					.nr_rates = 3, \
+					.rate_table = (unsigned int[]) { \
+						64000, 88200, 96000, \
+					} \
+				} \
+			}, \
+			{ \
+				QUIRK_DATA_AUDIOFORMAT(0) { \
+					.formats = SNDRV_PCM_FMTBIT_S32_LE, \
+					.channels = 8, /* inputs */ \
+					.fmt_bits = 24, \
+					.iface = 0, \
+					.altsetting = 1, \
+					.altset_idx = 1, \
+					.endpoint = 0x81, \
+					.ep_attr = USB_ENDPOINT_XFER_ISOC | \
+						USB_ENDPOINT_SYNC_ASYNC, \
+					.rates = SNDRV_PCM_RATE_KNOT | \
+						SNDRV_PCM_RATE_176400 | \
+						SNDRV_PCM_RATE_192000, \
+					.rate_min = 128000, \
+					.rate_max = 192000, \
+					.nr_rates = 3, \
+					.rate_table = (unsigned int[]) { \
+						128000, 176400, 192000, \
+					} \
+				} \
+			}, \
+			QUIRK_COMPOSITE_END \
+		} \
+	} \
+}
+
+QUIRK_RME_DIGIFACE(0x3f8c),
+QUIRK_RME_DIGIFACE(0x3fa0),
+
+#define QUIRK_AF16RIG(channel_count_, alt_setting_,			\
+	              low_rate_, high_rate_, pack_size_,		\
+		      clock_, interface_, endpoint_)			\
+	{ 								\
+		QUIRK_DATA_AUDIOFORMAT(interface_) {			\
+			.formats = SNDRV_PCM_FMTBIT_S32_LE,   		\
+			.channels = channel_count_,			\
+			.fmt_type = UAC_FORMAT_TYPE_I_PCM,		\
+			.fmt_bits = 24,					\
+			.fmt_sz = 4,					\
+			.iface = interface_,				\
+			.altsetting = alt_setting_,			\
+			.altset_idx = alt_setting_,			\
+			.endpoint = endpoint_,				\
+			.ep_attr = USB_ENDPOINT_XFER_ISOC |		\
+					USB_ENDPOINT_SYNC_ASYNC,	\
+			.datainterval = 1,				\
+			.protocol = UAC_VERSION_2,			\
+			.maxpacksize = pack_size_,			\
+			.rates = SNDRV_PCM_RATE_##low_rate_ |		\
+					SNDRV_PCM_RATE_##high_rate_,	\
+			.rate_min = low_rate_,				\
+			.rate_max = high_rate_,				\
+			.nr_rates = 2,					\
+			.rate_table = (unsigned int[]) {		\
+					low_rate_, high_rate_ },	\
+			.clock = clock_,				\
+		}							\
+	}
+
+#define QUIRK_AF16RIG_CLOCK(clock)					\
+	QUIRK_AF16RIG(34, 1,  44100,  48000, 0x3b8, clock, 1, 0x01),	\
+	QUIRK_AF16RIG(34, 1,  44100,  48000, 0x3b8, clock, 2, 0x81),	\
+	QUIRK_AF16RIG(18, 2,  88200,  96000, 0x3a8, clock, 1, 0x01),	\
+	QUIRK_AF16RIG(18, 2,  88200,  96000, 0x3a8, clock, 2, 0x81),	\
+	QUIRK_AF16RIG(10, 3, 176400, 192000, 0x3e8, clock, 1, 0x01),	\
+	QUIRK_AF16RIG(10, 3, 176400, 192000, 0x3e8, clock, 2, 0x81)
+
+/* Arturia AudioFuse 16Rig Audio */
+/* AF16Rig MIDI has USB PID 0xaf21 and appears to work OK without quirks */
+{
+	USB_DEVICE(0x1c75, 0xaf20),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "Arturia",
+		.product_name = "AF16Rig",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_STANDARD_MIXER(0) },
+			QUIRK_AF16RIG_CLOCK(41), /* Internal clock */
+#if 0
+/* These are disabled because I don't have the required hardware to test
+ * them. I suspect that the ADAT clock might not follow 176400 or 192000
+ * because the AF16Rig won't accept ADAT audio data at those rates.
+ */
+			QUIRK_AF16RIG_CLOCK(43), /* ADAT clock */
+			QUIRK_AF16RIG_CLOCK(44), /* BNC word clock */
+#endif
+			{ QUIRK_DATA_IGNORE(3) }, /* Firmware update */
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
+
+#undef QUIRK_AF16RIG_CLOCK
+#undef QUIRK_AF16RIG
+
+#undef USB_DEVICE_VENDOR_SPEC
+#undef USB_AUDIO_DEVICE
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
new file mode 100644
index 000000000..3afc49565
--- /dev/null
+++ b/sound/usb/quirks.c
@@ -0,0 +1,2837 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+#include <linux/cleanup.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/midi.h>
+#include <linux/bits.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "mixer.h"
+#include "mixer_quirks.h"
+#include "midi.h"
+#include "midi2.h"
+#include "quirks.h"
+#include "helper.h"
+#include "endpoint.h"
+#include "pcm.h"
+#include "clock.h"
+#include "stream.h"
+
+/*
+ * handle the quirks for the contained interfaces
+ */
+static int create_composite_quirk(struct snd_usb_audio *chip,
+				  struct usb_interface *iface,
+				  struct usb_driver *driver,
+				  const struct snd_usb_audio_quirk *quirk_comp)
+{
+	int probed_ifnum = get_iface_desc(iface->altsetting)->bInterfaceNumber;
+	const struct snd_usb_audio_quirk *quirk;
+	int err;
+
+	for (quirk = quirk_comp->data; quirk->ifnum >= 0; ++quirk) {
+		iface = usb_ifnum_to_if(chip->dev, quirk->ifnum);
+		if (!iface)
+			continue;
+		if (quirk->ifnum != probed_ifnum &&
+		    usb_interface_claimed(iface))
+			continue;
+		err = snd_usb_create_quirk(chip, iface, driver, quirk);
+		if (err < 0)
+			return err;
+	}
+
+	for (quirk = quirk_comp->data; quirk->ifnum >= 0; ++quirk) {
+		iface = usb_ifnum_to_if(chip->dev, quirk->ifnum);
+		if (!iface)
+			continue;
+		if (quirk->ifnum != probed_ifnum &&
+		    !usb_interface_claimed(iface)) {
+			err = usb_driver_claim_interface(driver, iface,
+							 USB_AUDIO_IFACE_UNUSED);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+static int ignore_interface_quirk(struct snd_usb_audio *chip,
+				  struct usb_interface *iface,
+				  struct usb_driver *driver,
+				  const struct snd_usb_audio_quirk *quirk)
+{
+	return 0;
+}
+
+
+static int create_any_midi_quirk(struct snd_usb_audio *chip,
+				 struct usb_interface *intf,
+				 struct usb_driver *driver,
+				 const struct snd_usb_audio_quirk *quirk)
+{
+	return snd_usb_midi_v2_create(chip, intf, quirk, 0);
+}
+
+/*
+ * create a stream for an interface with proper descriptors
+ */
+static int create_standard_audio_quirk(struct snd_usb_audio *chip,
+				       struct usb_interface *iface,
+				       struct usb_driver *driver,
+				       const struct snd_usb_audio_quirk *quirk)
+{
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	int err;
+
+	alts = &iface->altsetting[0];
+	altsd = get_iface_desc(alts);
+	err = snd_usb_parse_audio_interface(chip, altsd->bInterfaceNumber);
+	if (err < 0) {
+		usb_audio_err(chip, "cannot setup if %d: error %d\n",
+			   altsd->bInterfaceNumber, err);
+		return err;
+	}
+	/* reset the current interface */
+	usb_set_interface(chip->dev, altsd->bInterfaceNumber, 0);
+	return 0;
+}
+
+/* create the audio stream and the corresponding endpoints from the fixed
+ * audioformat object; this is used for quirks with the fixed EPs
+ */
+static int add_audio_stream_from_fixed_fmt(struct snd_usb_audio *chip,
+					   struct audioformat *fp)
+{
+	int stream, err;
+
+	stream = (fp->endpoint & USB_DIR_IN) ?
+		SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
+
+	snd_usb_audioformat_set_sync_ep(chip, fp);
+
+	err = snd_usb_add_audio_stream(chip, stream, fp, NULL);
+	if (err < 0)
+		return err;
+
+	err = snd_usb_add_endpoint(chip, fp->endpoint,
+				   SND_USB_ENDPOINT_TYPE_DATA);
+	if (err < 0)
+		return err;
+
+	if (fp->sync_ep) {
+		err = snd_usb_add_endpoint(chip, fp->sync_ep,
+					   fp->implicit_fb ?
+					   SND_USB_ENDPOINT_TYPE_DATA :
+					   SND_USB_ENDPOINT_TYPE_SYNC);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+/*
+ * create a stream for an endpoint/altsetting without proper descriptors
+ */
+static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
+				     struct usb_interface *iface,
+				     struct usb_driver *driver,
+				     const struct snd_usb_audio_quirk *quirk)
+{
+	struct audioformat *fp;
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	unsigned *rate_table = NULL;
+	int err;
+
+	fp = kmemdup(quirk->data, sizeof(*fp), GFP_KERNEL);
+	if (!fp)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&fp->list);
+	if (fp->nr_rates > MAX_NR_RATES) {
+		kfree(fp);
+		return -EINVAL;
+	}
+	if (fp->nr_rates > 0) {
+		rate_table = kmemdup_array(fp->rate_table, fp->nr_rates, sizeof(int),
+					   GFP_KERNEL);
+		if (!rate_table) {
+			kfree(fp);
+			return -ENOMEM;
+		}
+		fp->rate_table = rate_table;
+	}
+
+	if (fp->iface != get_iface_desc(&iface->altsetting[0])->bInterfaceNumber ||
+	    fp->altset_idx >= iface->num_altsetting) {
+		err = -EINVAL;
+		goto error;
+	}
+	alts = &iface->altsetting[fp->altset_idx];
+	altsd = get_iface_desc(alts);
+	if (altsd->bNumEndpoints <= fp->ep_idx) {
+		err = -EINVAL;
+		goto error;
+	}
+
+	fp->protocol = altsd->bInterfaceProtocol;
+
+	if (fp->datainterval == 0)
+		fp->datainterval = snd_usb_parse_datainterval(chip, alts);
+	if (fp->maxpacksize == 0)
+		fp->maxpacksize = le16_to_cpu(get_endpoint(alts, fp->ep_idx)->wMaxPacketSize);
+	if (!fp->fmt_type)
+		fp->fmt_type = UAC_FORMAT_TYPE_I;
+
+	err = add_audio_stream_from_fixed_fmt(chip, fp);
+	if (err < 0)
+		goto error;
+
+	usb_set_interface(chip->dev, fp->iface, 0);
+	snd_usb_init_pitch(chip, fp);
+	snd_usb_init_sample_rate(chip, fp, fp->rate_max);
+	return 0;
+
+ error:
+	list_del(&fp->list); /* unlink for avoiding double-free */
+	kfree(fp);
+	kfree(rate_table);
+	return err;
+}
+
+static int create_auto_pcm_quirk(struct snd_usb_audio *chip,
+				 struct usb_interface *iface,
+				 struct usb_driver *driver)
+{
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct usb_endpoint_descriptor *epd;
+	struct uac1_as_header_descriptor *ashd;
+	struct uac_format_type_i_discrete_descriptor *fmtd;
+
+	/*
+	 * Most Roland/Yamaha audio streaming interfaces have more or less
+	 * standard descriptors, but older devices might lack descriptors, and
+	 * future ones might change, so ensure that we fail silently if the
+	 * interface doesn't look exactly right.
+	 */
+
+	/* must have a non-zero altsetting for streaming */
+	if (iface->num_altsetting < 2)
+		return -ENODEV;
+	alts = &iface->altsetting[1];
+	altsd = get_iface_desc(alts);
+
+	/* must have an isochronous endpoint for streaming */
+	if (altsd->bNumEndpoints < 1)
+		return -ENODEV;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_xfer_isoc(epd))
+		return -ENODEV;
+
+	/* must have format descriptors */
+	ashd = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
+				       UAC_AS_GENERAL);
+	fmtd = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
+				       UAC_FORMAT_TYPE);
+	if (!ashd || ashd->bLength < 7 ||
+	    !fmtd || fmtd->bLength < 8)
+		return -ENODEV;
+
+	return create_standard_audio_quirk(chip, iface, driver, NULL);
+}
+
+static int create_yamaha_midi_quirk(struct snd_usb_audio *chip,
+				    struct usb_interface *iface,
+				    struct usb_driver *driver,
+				    struct usb_host_interface *alts)
+{
+	static const struct snd_usb_audio_quirk yamaha_midi_quirk = {
+		.type = QUIRK_MIDI_YAMAHA
+	};
+	struct usb_midi_in_jack_descriptor *injd;
+	struct usb_midi_out_jack_descriptor *outjd;
+
+	/* must have some valid jack descriptors */
+	injd = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+				       NULL, USB_MS_MIDI_IN_JACK);
+	outjd = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+					NULL, USB_MS_MIDI_OUT_JACK);
+	if (!injd && !outjd)
+		return -ENODEV;
+	if ((injd && !snd_usb_validate_midi_desc(injd)) ||
+	    (outjd && !snd_usb_validate_midi_desc(outjd)))
+		return -ENODEV;
+	if (injd && (injd->bLength < 5 ||
+		     (injd->bJackType != USB_MS_EMBEDDED &&
+		      injd->bJackType != USB_MS_EXTERNAL)))
+		return -ENODEV;
+	if (outjd && (outjd->bLength < 6 ||
+		      (outjd->bJackType != USB_MS_EMBEDDED &&
+		       outjd->bJackType != USB_MS_EXTERNAL)))
+		return -ENODEV;
+	return create_any_midi_quirk(chip, iface, driver, &yamaha_midi_quirk);
+}
+
+static int create_roland_midi_quirk(struct snd_usb_audio *chip,
+				    struct usb_interface *iface,
+				    struct usb_driver *driver,
+				    struct usb_host_interface *alts)
+{
+	static const struct snd_usb_audio_quirk roland_midi_quirk = {
+		.type = QUIRK_MIDI_ROLAND
+	};
+	u8 *roland_desc = NULL;
+
+	/* might have a vendor-specific descriptor <06 24 F1 02 ...> */
+	for (;;) {
+		roland_desc = snd_usb_find_csint_desc(alts->extra,
+						      alts->extralen,
+						      roland_desc, 0xf1);
+		if (!roland_desc)
+			return -ENODEV;
+		if (roland_desc[0] < 6 || roland_desc[3] != 2)
+			continue;
+		return create_any_midi_quirk(chip, iface, driver,
+					     &roland_midi_quirk);
+	}
+}
+
+static int create_std_midi_quirk(struct snd_usb_audio *chip,
+				 struct usb_interface *iface,
+				 struct usb_driver *driver,
+				 struct usb_host_interface *alts)
+{
+	struct usb_ms_header_descriptor *mshd;
+	struct usb_ms_endpoint_descriptor *msepd;
+
+	/* must have the MIDIStreaming interface header descriptor*/
+	mshd = (struct usb_ms_header_descriptor *)alts->extra;
+	if (alts->extralen < 7 ||
+	    mshd->bLength < 7 ||
+	    mshd->bDescriptorType != USB_DT_CS_INTERFACE ||
+	    mshd->bDescriptorSubtype != USB_MS_HEADER)
+		return -ENODEV;
+	/* must have the MIDIStreaming endpoint descriptor*/
+	msepd = (struct usb_ms_endpoint_descriptor *)alts->endpoint[0].extra;
+	if (alts->endpoint[0].extralen < 4 ||
+	    msepd->bLength < 4 ||
+	    msepd->bDescriptorType != USB_DT_CS_ENDPOINT ||
+	    msepd->bDescriptorSubtype != UAC_MS_GENERAL ||
+	    msepd->bNumEmbMIDIJack < 1 ||
+	    msepd->bNumEmbMIDIJack > 16)
+		return -ENODEV;
+
+	return create_any_midi_quirk(chip, iface, driver, NULL);
+}
+
+static int create_auto_midi_quirk(struct snd_usb_audio *chip,
+				  struct usb_interface *iface,
+				  struct usb_driver *driver)
+{
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct usb_endpoint_descriptor *epd;
+	int err;
+
+	alts = &iface->altsetting[0];
+	altsd = get_iface_desc(alts);
+
+	/* must have at least one bulk/interrupt endpoint for streaming */
+	if (altsd->bNumEndpoints < 1)
+		return -ENODEV;
+	epd = get_endpoint(alts, 0);
+	if (!usb_endpoint_xfer_bulk(epd) &&
+	    !usb_endpoint_xfer_int(epd))
+		return -ENODEV;
+
+	switch (USB_ID_VENDOR(chip->usb_id)) {
+	case 0x0499: /* Yamaha */
+		err = create_yamaha_midi_quirk(chip, iface, driver, alts);
+		if (err != -ENODEV)
+			return err;
+		break;
+	case 0x0582: /* Roland */
+		err = create_roland_midi_quirk(chip, iface, driver, alts);
+		if (err != -ENODEV)
+			return err;
+		break;
+	}
+
+	return create_std_midi_quirk(chip, iface, driver, alts);
+}
+
+static int create_autodetect_quirk(struct snd_usb_audio *chip,
+				   struct usb_interface *iface,
+				   struct usb_driver *driver,
+				   const struct snd_usb_audio_quirk *quirk)
+{
+	int err;
+
+	err = create_auto_pcm_quirk(chip, iface, driver);
+	if (err == -ENODEV)
+		err = create_auto_midi_quirk(chip, iface, driver);
+	return err;
+}
+
+/*
+ * Create a stream for an Edirol UA-700/UA-25/UA-4FX interface.  
+ * The only way to detect the sample rate is by looking at wMaxPacketSize.
+ */
+static int create_uaxx_quirk(struct snd_usb_audio *chip,
+			     struct usb_interface *iface,
+			     struct usb_driver *driver,
+			     const struct snd_usb_audio_quirk *quirk)
+{
+	static const struct audioformat ua_format = {
+		.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+		.channels = 2,
+		.fmt_type = UAC_FORMAT_TYPE_I,
+		.altsetting = 1,
+		.altset_idx = 1,
+		.rates = SNDRV_PCM_RATE_CONTINUOUS,
+	};
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct audioformat *fp;
+	int err;
+
+	/* both PCM and MIDI interfaces have 2 or more altsettings */
+	if (iface->num_altsetting < 2)
+		return -ENXIO;
+	alts = &iface->altsetting[1];
+	altsd = get_iface_desc(alts);
+
+	if (altsd->bNumEndpoints == 2) {
+		static const struct snd_usb_midi_endpoint_info ua700_ep = {
+			.out_cables = 0x0003,
+			.in_cables  = 0x0003
+		};
+		static const struct snd_usb_audio_quirk ua700_quirk = {
+			.type = QUIRK_MIDI_FIXED_ENDPOINT,
+			.data = &ua700_ep
+		};
+		static const struct snd_usb_midi_endpoint_info uaxx_ep = {
+			.out_cables = 0x0001,
+			.in_cables  = 0x0001
+		};
+		static const struct snd_usb_audio_quirk uaxx_quirk = {
+			.type = QUIRK_MIDI_FIXED_ENDPOINT,
+			.data = &uaxx_ep
+		};
+		const struct snd_usb_audio_quirk *quirk =
+			chip->usb_id == USB_ID(0x0582, 0x002b)
+			? &ua700_quirk : &uaxx_quirk;
+		return __snd_usbmidi_create(chip->card, iface,
+					    &chip->midi_list, quirk,
+					    chip->usb_id,
+					    &chip->num_rawmidis);
+	}
+
+	if (altsd->bNumEndpoints != 1)
+		return -ENXIO;
+
+	fp = kmemdup(&ua_format, sizeof(*fp), GFP_KERNEL);
+	if (!fp)
+		return -ENOMEM;
+
+	fp->iface = altsd->bInterfaceNumber;
+	fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
+	fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
+	fp->datainterval = 0;
+	fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+	INIT_LIST_HEAD(&fp->list);
+
+	switch (fp->maxpacksize) {
+	case 0x120:
+		fp->rate_max = fp->rate_min = 44100;
+		break;
+	case 0x138:
+	case 0x140:
+		fp->rate_max = fp->rate_min = 48000;
+		break;
+	case 0x258:
+	case 0x260:
+		fp->rate_max = fp->rate_min = 96000;
+		break;
+	default:
+		usb_audio_err(chip, "unknown sample rate\n");
+		kfree(fp);
+		return -ENXIO;
+	}
+
+	err = add_audio_stream_from_fixed_fmt(chip, fp);
+	if (err < 0) {
+		list_del(&fp->list); /* unlink for avoiding double-free */
+		kfree(fp);
+		return err;
+	}
+	usb_set_interface(chip->dev, fp->iface, 0);
+	return 0;
+}
+
+/*
+ * Create a standard mixer for the specified interface.
+ */
+static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
+				       struct usb_interface *iface,
+				       struct usb_driver *driver,
+				       const struct snd_usb_audio_quirk *quirk)
+{
+	if (quirk->ifnum < 0)
+		return 0;
+
+	return snd_usb_create_mixer(chip, quirk->ifnum);
+}
+
+/*
+ * audio-interface quirks
+ *
+ * returns zero if no standard audio/MIDI parsing is needed.
+ * returns a positive value if standard audio/midi interfaces are parsed
+ * after this.
+ * returns a negative value at error.
+ */
+int snd_usb_create_quirk(struct snd_usb_audio *chip,
+			 struct usb_interface *iface,
+			 struct usb_driver *driver,
+			 const struct snd_usb_audio_quirk *quirk)
+{
+	typedef int (*quirk_func_t)(struct snd_usb_audio *,
+				    struct usb_interface *,
+				    struct usb_driver *,
+				    const struct snd_usb_audio_quirk *);
+	static const quirk_func_t quirk_funcs[] = {
+		[QUIRK_IGNORE_INTERFACE] = ignore_interface_quirk,
+		[QUIRK_COMPOSITE] = create_composite_quirk,
+		[QUIRK_AUTODETECT] = create_autodetect_quirk,
+		[QUIRK_MIDI_STANDARD_INTERFACE] = create_any_midi_quirk,
+		[QUIRK_MIDI_FIXED_ENDPOINT] = create_any_midi_quirk,
+		[QUIRK_MIDI_YAMAHA] = create_any_midi_quirk,
+		[QUIRK_MIDI_ROLAND] = create_any_midi_quirk,
+		[QUIRK_MIDI_MIDIMAN] = create_any_midi_quirk,
+		[QUIRK_MIDI_NOVATION] = create_any_midi_quirk,
+		[QUIRK_MIDI_RAW_BYTES] = create_any_midi_quirk,
+		[QUIRK_MIDI_EMAGIC] = create_any_midi_quirk,
+		[QUIRK_MIDI_CME] = create_any_midi_quirk,
+		[QUIRK_MIDI_AKAI] = create_any_midi_quirk,
+		[QUIRK_MIDI_FTDI] = create_any_midi_quirk,
+		[QUIRK_MIDI_CH345] = create_any_midi_quirk,
+		[QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_audio_quirk,
+		[QUIRK_AUDIO_FIXED_ENDPOINT] = create_fixed_stream_quirk,
+		[QUIRK_AUDIO_EDIROL_UAXX] = create_uaxx_quirk,
+		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
+	};
+
+	if (quirk->type < QUIRK_TYPE_COUNT) {
+		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
+	} else {
+		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
+		return -ENXIO;
+	}
+}
+
+/*
+ * boot quirks
+ */
+
+#define EXTIGY_FIRMWARE_SIZE_OLD 794
+#define EXTIGY_FIRMWARE_SIZE_NEW 483
+
+static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interface *intf)
+{
+	struct usb_host_config *config = dev->actconfig;
+	int err;
+
+	if (le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_OLD ||
+	    le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_NEW) {
+		dev_dbg(&dev->dev, "sending Extigy boot sequence...\n");
+		/* Send message to force it to reconnect with full interface. */
+		err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev,0),
+				      0x10, 0x43, 0x0001, 0x000a, NULL, 0);
+		if (err < 0)
+			dev_dbg(&dev->dev, "error sending boot message: %d\n", err);
+		struct usb_device_descriptor *new_device_descriptor __free(kfree) =
+			kmalloc_obj(*new_device_descriptor);
+		if (!new_device_descriptor)
+			return -ENOMEM;
+		err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
+				new_device_descriptor, sizeof(*new_device_descriptor));
+		if (err < 0)
+			dev_dbg(&dev->dev, "error usb_get_descriptor: %d\n", err);
+		if (new_device_descriptor->bNumConfigurations > dev->descriptor.bNumConfigurations)
+			dev_dbg(&dev->dev, "error too large bNumConfigurations: %d\n",
+				new_device_descriptor->bNumConfigurations);
+		else
+			memcpy(&dev->descriptor, new_device_descriptor, sizeof(dev->descriptor));
+		err = usb_reset_configuration(dev);
+		if (err < 0)
+			dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);
+		dev_dbg(&dev->dev, "extigy_boot: new boot length = %d\n",
+			    le16_to_cpu(get_cfg_desc(config)->wTotalLength));
+		return -ENODEV; /* quit this anyway */
+	}
+	return 0;
+}
+
+static int snd_usb_audigy2nx_boot_quirk(struct usb_device *dev)
+{
+	u8 buf = 1;
+
+	snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), 0x2a,
+			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+			0, 0, &buf, 1);
+	if (buf == 0) {
+		snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0x29,
+				USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
+				1, 2000, NULL, 0);
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static int snd_usb_fasttrackpro_boot_quirk(struct usb_device *dev)
+{
+	int err;
+
+	if (dev->actconfig->desc.bConfigurationValue == 1) {
+		dev_info(&dev->dev,
+			   "Fast Track Pro switching to config #2\n");
+		/* This function has to be available by the usb core module.
+		 * if it is not avialable the boot quirk has to be left out
+		 * and the configuration has to be set by udev or hotplug
+		 * rules
+		 */
+		err = usb_driver_set_configuration(dev, 2);
+		if (err < 0)
+			dev_dbg(&dev->dev,
+				"error usb_driver_set_configuration: %d\n",
+				err);
+		/* Always return an error, so that we stop creating a device
+		   that will just be destroyed and recreated with a new
+		   configuration */
+		return -ENODEV;
+	} else
+		dev_info(&dev->dev, "Fast Track Pro config OK\n");
+
+	return 0;
+}
+
+/*
+ * C-Media CM106/CM106+ have four 16-bit internal registers that are nicely
+ * documented in the device's data sheet.
+ */
+static int snd_usb_cm106_write_int_reg(struct usb_device *dev, int reg, u16 value)
+{
+	u8 buf[4];
+	buf[0] = 0x20;
+	buf[1] = value & 0xff;
+	buf[2] = (value >> 8) & 0xff;
+	buf[3] = reg;
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), USB_REQ_SET_CONFIGURATION,
+			       USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
+			       0, 0, &buf, 4);
+}
+
+static int snd_usb_cm106_boot_quirk(struct usb_device *dev)
+{
+	/*
+	 * Enable line-out driver mode, set headphone source to front
+	 * channels, enable stereo mic.
+	 */
+	return snd_usb_cm106_write_int_reg(dev, 2, 0x8004);
+}
+
+/*
+ * CM6206 registers from the CM6206 datasheet rev 2.1
+ */
+#define CM6206_REG0_DMA_MASTER BIT(15)
+#define CM6206_REG0_SPDIFO_RATE_48K (2 << 12)
+#define CM6206_REG0_SPDIFO_RATE_96K (7 << 12)
+/* Bit 4 thru 11 is the S/PDIF category code */
+#define CM6206_REG0_SPDIFO_CAT_CODE_GENERAL (0 << 4)
+#define CM6206_REG0_SPDIFO_EMPHASIS_CD BIT(3)
+#define CM6206_REG0_SPDIFO_COPYRIGHT_NA BIT(2)
+#define CM6206_REG0_SPDIFO_NON_AUDIO BIT(1)
+#define CM6206_REG0_SPDIFO_PRO_FORMAT BIT(0)
+
+#define CM6206_REG1_TEST_SEL_CLK BIT(14)
+#define CM6206_REG1_PLLBIN_EN BIT(13)
+#define CM6206_REG1_SOFT_MUTE_EN BIT(12)
+#define CM6206_REG1_GPIO4_OUT BIT(11)
+#define CM6206_REG1_GPIO4_OE BIT(10)
+#define CM6206_REG1_GPIO3_OUT BIT(9)
+#define CM6206_REG1_GPIO3_OE BIT(8)
+#define CM6206_REG1_GPIO2_OUT BIT(7)
+#define CM6206_REG1_GPIO2_OE BIT(6)
+#define CM6206_REG1_GPIO1_OUT BIT(5)
+#define CM6206_REG1_GPIO1_OE BIT(4)
+#define CM6206_REG1_SPDIFO_INVALID BIT(3)
+#define CM6206_REG1_SPDIF_LOOP_EN BIT(2)
+#define CM6206_REG1_SPDIFO_DIS BIT(1)
+#define CM6206_REG1_SPDIFI_MIX BIT(0)
+
+#define CM6206_REG2_DRIVER_ON BIT(15)
+#define CM6206_REG2_HEADP_SEL_SIDE_CHANNELS (0 << 13)
+#define CM6206_REG2_HEADP_SEL_SURROUND_CHANNELS (1 << 13)
+#define CM6206_REG2_HEADP_SEL_CENTER_SUBW (2 << 13)
+#define CM6206_REG2_HEADP_SEL_FRONT_CHANNELS (3 << 13)
+#define CM6206_REG2_MUTE_HEADPHONE_RIGHT BIT(12)
+#define CM6206_REG2_MUTE_HEADPHONE_LEFT BIT(11)
+#define CM6206_REG2_MUTE_REAR_SURROUND_RIGHT BIT(10)
+#define CM6206_REG2_MUTE_REAR_SURROUND_LEFT BIT(9)
+#define CM6206_REG2_MUTE_SIDE_SURROUND_RIGHT BIT(8)
+#define CM6206_REG2_MUTE_SIDE_SURROUND_LEFT BIT(7)
+#define CM6206_REG2_MUTE_SUBWOOFER BIT(6)
+#define CM6206_REG2_MUTE_CENTER BIT(5)
+#define CM6206_REG2_MUTE_RIGHT_FRONT BIT(3)
+#define CM6206_REG2_MUTE_LEFT_FRONT BIT(3)
+#define CM6206_REG2_EN_BTL BIT(2)
+#define CM6206_REG2_MCUCLKSEL_1_5_MHZ (0)
+#define CM6206_REG2_MCUCLKSEL_3_MHZ (1)
+#define CM6206_REG2_MCUCLKSEL_6_MHZ (2)
+#define CM6206_REG2_MCUCLKSEL_12_MHZ (3)
+
+/* Bit 11..13 sets the sensitivity to FLY tuner volume control VP/VD signal */
+#define CM6206_REG3_FLYSPEED_DEFAULT (2 << 11)
+#define CM6206_REG3_VRAP25EN BIT(10)
+#define CM6206_REG3_MSEL1 BIT(9)
+#define CM6206_REG3_SPDIFI_RATE_44_1K BIT(0 << 7)
+#define CM6206_REG3_SPDIFI_RATE_48K BIT(2 << 7)
+#define CM6206_REG3_SPDIFI_RATE_32K BIT(3 << 7)
+#define CM6206_REG3_PINSEL BIT(6)
+#define CM6206_REG3_FOE BIT(5)
+#define CM6206_REG3_ROE BIT(4)
+#define CM6206_REG3_CBOE BIT(3)
+#define CM6206_REG3_LOSE BIT(2)
+#define CM6206_REG3_HPOE BIT(1)
+#define CM6206_REG3_SPDIFI_CANREC BIT(0)
+
+#define CM6206_REG5_DA_RSTN BIT(13)
+#define CM6206_REG5_AD_RSTN BIT(12)
+#define CM6206_REG5_SPDIFO_AD2SPDO BIT(12)
+#define CM6206_REG5_SPDIFO_SEL_FRONT (0 << 9)
+#define CM6206_REG5_SPDIFO_SEL_SIDE_SUR (1 << 9)
+#define CM6206_REG5_SPDIFO_SEL_CEN_LFE (2 << 9)
+#define CM6206_REG5_SPDIFO_SEL_REAR_SUR (3 << 9)
+#define CM6206_REG5_CODECM BIT(8)
+#define CM6206_REG5_EN_HPF BIT(7)
+#define CM6206_REG5_T_SEL_DSDA4 BIT(6)
+#define CM6206_REG5_T_SEL_DSDA3 BIT(5)
+#define CM6206_REG5_T_SEL_DSDA2 BIT(4)
+#define CM6206_REG5_T_SEL_DSDA1 BIT(3)
+#define CM6206_REG5_T_SEL_DSDAD_NORMAL 0
+#define CM6206_REG5_T_SEL_DSDAD_FRONT 4
+#define CM6206_REG5_T_SEL_DSDAD_S_SURROUND 5
+#define CM6206_REG5_T_SEL_DSDAD_CEN_LFE 6
+#define CM6206_REG5_T_SEL_DSDAD_R_SURROUND 7
+
+static int snd_usb_cm6206_boot_quirk(struct usb_device *dev)
+{
+	int err  = 0, reg;
+	int val[] = {
+		/*
+		 * Values here are chosen based on sniffing USB traffic
+		 * under Windows.
+		 *
+		 * REG0: DAC is master, sample rate 48kHz, no copyright
+		 */
+		CM6206_REG0_SPDIFO_RATE_48K |
+		CM6206_REG0_SPDIFO_COPYRIGHT_NA,
+		/*
+		 * REG1: PLL binary search enable, soft mute enable.
+		 */
+		CM6206_REG1_PLLBIN_EN |
+		CM6206_REG1_SOFT_MUTE_EN,
+		/*
+		 * REG2: enable output drivers,
+		 * select front channels to the headphone output,
+		 * then mute the headphone channels, run the MCU
+		 * at 1.5 MHz.
+		 */
+		CM6206_REG2_DRIVER_ON |
+		CM6206_REG2_HEADP_SEL_FRONT_CHANNELS |
+		CM6206_REG2_MUTE_HEADPHONE_RIGHT |
+		CM6206_REG2_MUTE_HEADPHONE_LEFT,
+		/*
+		 * REG3: default flyspeed, set 2.5V mic bias
+		 * enable all line out ports and enable SPDIF
+		 */
+		CM6206_REG3_FLYSPEED_DEFAULT |
+		CM6206_REG3_VRAP25EN |
+		CM6206_REG3_FOE |
+		CM6206_REG3_ROE |
+		CM6206_REG3_CBOE |
+		CM6206_REG3_LOSE |
+		CM6206_REG3_HPOE |
+		CM6206_REG3_SPDIFI_CANREC,
+		/* REG4 is just a bunch of GPIO lines */
+		0x0000,
+		/* REG5: de-assert AD/DA reset signals */
+		CM6206_REG5_DA_RSTN |
+		CM6206_REG5_AD_RSTN };
+
+	for (reg = 0; reg < ARRAY_SIZE(val); reg++) {
+		err = snd_usb_cm106_write_int_reg(dev, reg, val[reg]);
+		if (err < 0)
+			return err;
+	}
+
+	return err;
+}
+
+/* quirk for Plantronics GameCom 780 with CM6302 chip */
+static int snd_usb_gamecon780_boot_quirk(struct usb_device *dev)
+{
+	/* set the initial volume and don't change; other values are either
+	 * too loud or silent due to firmware bug (bko#65251)
+	 */
+	u8 buf[2] = { 0x74, 0xe3 };
+	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+			UAC_FU_VOLUME << 8, 9 << 8, buf, 2);
+}
+
+/*
+ * Novation Twitch DJ controller
+ * Focusrite Novation Saffire 6 USB audio card
+ */
+static int snd_usb_novation_boot_quirk(struct usb_device *dev)
+{
+	/* preemptively set up the device because otherwise the
+	 * raw MIDI endpoints are not active */
+	usb_set_interface(dev, 0, 1);
+	return 0;
+}
+
+/*
+ * This call will put the synth in "USB send" mode, i.e it will send MIDI
+ * messages through USB (this is disabled at startup). The synth will
+ * acknowledge by sending a sysex on endpoint 0x85 and by displaying a USB
+ * sign on its LCD. Values here are chosen based on sniffing USB traffic
+ * under Windows.
+ */
+static int snd_usb_accessmusic_boot_quirk(struct usb_device *dev)
+{
+	int err, actual_length;
+	/* "midi send" enable */
+	static const u8 seq[] = { 0x4e, 0x73, 0x52, 0x01 };
+	void *buf;
+
+	if (usb_pipe_type_check(dev, usb_sndintpipe(dev, 0x05)))
+		return -EINVAL;
+	buf = kmemdup(seq, ARRAY_SIZE(seq), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	err = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x05), buf,
+			ARRAY_SIZE(seq), &actual_length, 1000);
+	kfree(buf);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/*
+ * A post configuration device descriptor read is needed to make the CM1A
+ * operational after reenumeration.
+ */
+static int snd_usb_cm1a_boot_quirk(struct usb_device *dev)
+{
+	struct usb_device_descriptor *desc __free(kfree) = kmalloc_obj(*desc);
+	int err;
+
+	if (!desc)
+		return -ENOMEM;
+
+	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, sizeof(*desc));
+	if (err < 0) {
+		dev_err(&dev->dev, "failed to read device descriptor: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+/*
+ * Some sound cards from Native Instruments are in fact compliant to the USB
+ * audio standard of version 2 and other approved USB standards, even though
+ * they come up as vendor-specific device when first connected.
+ *
+ * However, they can be told to come up with a new set of descriptors
+ * upon their next enumeration, and the interfaces announced by the new
+ * descriptors will then be handled by the kernel's class drivers. As the
+ * product ID will also change, no further checks are required.
+ */
+
+static int snd_usb_nativeinstruments_boot_quirk(struct usb_device *dev)
+{
+	int ret;
+
+	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+				  0xaf, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+				  1, 0, NULL, 0, 1000);
+
+	if (ret < 0)
+		return ret;
+
+	usb_reset_device(dev);
+
+	/* return -EAGAIN, so the creation of an audio interface for this
+	 * temporary device is aborted. The device will reconnect with a
+	 * new product ID */
+	return -EAGAIN;
+}
+
+static void mbox2_setup_48_24_magic(struct usb_device *dev)
+{
+	u8 srate[3];
+	u8 temp[12];
+
+	/* Choose 48000Hz permanently */
+	srate[0] = 0x80;
+	srate[1] = 0xbb;
+	srate[2] = 0x00;
+
+	/* Send the magic! */
+	snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+		0x01, 0x22, 0x0100, 0x0085, &temp, 0x0003);
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+		0x81, 0xa2, 0x0100, 0x0085, &srate, 0x0003);
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+		0x81, 0xa2, 0x0100, 0x0086, &srate, 0x0003);
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+		0x81, 0xa2, 0x0100, 0x0003, &srate, 0x0003);
+	return;
+}
+
+/* Digidesign Mbox 2 needs to load firmware onboard
+ * and driver must wait a few seconds for initialisation.
+ */
+
+#define MBOX2_FIRMWARE_SIZE    646
+#define MBOX2_BOOT_LOADING     0x01 /* Hard coded into the device */
+#define MBOX2_BOOT_READY       0x02 /* Hard coded into the device */
+
+static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
+{
+	struct usb_host_config *config = dev->actconfig;
+	int err;
+	u8 bootresponse[0x12];
+	int fwsize;
+	int count;
+
+	fwsize = le16_to_cpu(get_cfg_desc(config)->wTotalLength);
+
+	if (fwsize != MBOX2_FIRMWARE_SIZE) {
+		dev_err(&dev->dev, "Invalid firmware size=%d.\n", fwsize);
+		return -ENODEV;
+	}
+
+	dev_dbg(&dev->dev, "Sending Digidesign Mbox 2 boot sequence...\n");
+
+	count = 0;
+	bootresponse[0] = MBOX2_BOOT_LOADING;
+	while ((bootresponse[0] == MBOX2_BOOT_LOADING) && (count < 10)) {
+		msleep(500); /* 0.5 second delay */
+		snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+			/* Control magic - load onboard firmware */
+			0x85, 0xc0, 0x0001, 0x0000, &bootresponse, 0x0012);
+		if (bootresponse[0] == MBOX2_BOOT_READY)
+			break;
+		dev_dbg(&dev->dev, "device not ready, resending boot sequence...\n");
+		count++;
+	}
+
+	if (bootresponse[0] != MBOX2_BOOT_READY) {
+		dev_err(&dev->dev, "Unknown bootresponse=%d, or timed out, ignoring device.\n", bootresponse[0]);
+		return -ENODEV;
+	}
+
+	dev_dbg(&dev->dev, "device initialised!\n");
+
+	struct usb_device_descriptor *new_device_descriptor __free(kfree) =
+		kmalloc_obj(*new_device_descriptor);
+	if (!new_device_descriptor)
+		return -ENOMEM;
+
+	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
+		new_device_descriptor, sizeof(*new_device_descriptor));
+	if (err < 0)
+		dev_dbg(&dev->dev, "error usb_get_descriptor: %d\n", err);
+	if (new_device_descriptor->bNumConfigurations > dev->descriptor.bNumConfigurations)
+		dev_dbg(&dev->dev, "error too large bNumConfigurations: %d\n",
+			new_device_descriptor->bNumConfigurations);
+	else
+		memcpy(&dev->descriptor, new_device_descriptor, sizeof(dev->descriptor));
+
+	err = usb_reset_configuration(dev);
+	if (err < 0)
+		dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);
+	dev_dbg(&dev->dev, "mbox2_boot: new boot length = %d\n",
+		le16_to_cpu(get_cfg_desc(config)->wTotalLength));
+
+	mbox2_setup_48_24_magic(dev);
+
+	dev_info(&dev->dev, "Digidesign Mbox 2: 24bit 48kHz");
+
+	return 0; /* Successful boot */
+}
+
+static int snd_usb_axefx3_boot_quirk(struct usb_device *dev)
+{
+	int err;
+
+	dev_dbg(&dev->dev, "Waiting for Axe-Fx III to boot up...\n");
+
+	/* If the Axe-Fx III has not fully booted, it will timeout when trying
+	 * to enable the audio streaming interface. A more generous timeout is
+	 * used here to detect when the Axe-Fx III has finished booting as the
+	 * set interface message will be acked once it has
+	 */
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+				USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
+				1, 1, NULL, 0, 120000);
+	if (err < 0) {
+		dev_err(&dev->dev,
+			"failed waiting for Axe-Fx III to boot: %d\n", err);
+		return err;
+	}
+
+	dev_dbg(&dev->dev, "Axe-Fx III is now ready\n");
+
+	err = usb_set_interface(dev, 1, 0);
+	if (err < 0)
+		dev_dbg(&dev->dev,
+			"error stopping Axe-Fx III interface: %d\n", err);
+
+	return 0;
+}
+
+static void mbox3_setup_defaults(struct usb_device *dev)
+{
+	/* The Mbox 3 is "little endian" */
+	/* max volume is: 0x0000. */
+	/* min volume is: 0x0080 (shown in little endian form) */
+
+	u8 com_buff[2];
+
+	/* Deactivate Tuner */
+	/* on  = 0x01*/
+	/* off = 0x00*/
+	com_buff[0] = 0x00;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+		0x01, 0x21, 0x0003, 0x2001, &com_buff, 1);
+
+	/* Set clock source to Internal (as opposed to S/PDIF) */
+	/* Internal  = 0x01*/
+	/* S/PDIF    = 0x02*/
+	com_buff[0] = 0x01;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0100, 0x8001, &com_buff, 1);
+
+	/* Mute the hardware loopbacks to start the device in a known state. */
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x80;
+	/* Analogue input 1 left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0110, 0x4001, &com_buff, 2);
+	/* Analogue input 1 right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0111, 0x4001, &com_buff, 2);
+	/* Analogue input 2 left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0114, 0x4001, &com_buff, 2);
+	/* Analogue input 2 right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0115, 0x4001, &com_buff, 2);
+	/* Analogue input 3 left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0118, 0x4001, &com_buff, 2);
+	/* Analogue input 3 right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0119, 0x4001, &com_buff, 2);
+	/* Analogue input 4 left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x011c, 0x4001, &com_buff, 2);
+	/* Analogue input 4 right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x011d, 0x4001, &com_buff, 2);
+
+	/* Set software sends to output */
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x00;
+	/* Analogue software return 1 left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0100, 0x4001, &com_buff, 2);
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x80;
+	/* Analogue software return 1 right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0101, 0x4001, &com_buff, 2);
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x80;
+	/* Analogue software return 2 left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0104, 0x4001, &com_buff, 2);
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x00;
+	/* Analogue software return 2 right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0105, 0x4001, &com_buff, 2);
+
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x80;
+	/* Analogue software return 3 left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0108, 0x4001, &com_buff, 2);
+	/* Analogue software return 3 right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0109, 0x4001, &com_buff, 2);
+	/* Analogue software return 4 left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x010c, 0x4001, &com_buff, 2);
+	/* Analogue software return 4 right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x010d, 0x4001, &com_buff, 2);
+
+	/* Return to muting sends */
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x80;
+	/* Analogue fx return left channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0120, 0x4001, &com_buff, 2);
+	/* Analogue fx return right channel: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0121, 0x4001, &com_buff, 2);
+
+	/* Analogue software input 1 fx send: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0100, 0x4201, &com_buff, 2);
+	/* Analogue software input 2 fx send: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0101, 0x4201, &com_buff, 2);
+	/* Analogue software input 3 fx send: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0102, 0x4201, &com_buff, 2);
+	/* Analogue software input 4 fx send: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0103, 0x4201, &com_buff, 2);
+	/* Analogue input 1 fx send: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0104, 0x4201, &com_buff, 2);
+	/* Analogue input 2 fx send: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0105, 0x4201, &com_buff, 2);
+	/* Analogue input 3 fx send: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0106, 0x4201, &com_buff, 2);
+	/* Analogue input 4 fx send: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0107, 0x4201, &com_buff, 2);
+
+	/* Toggle allowing host control */
+	/* Not needed
+	com_buff[0] = 0x02;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			3, 0x21, 0x0000, 0x2001, &com_buff, 1);
+	 */
+
+	/* Do not dim fx returns */
+	com_buff[0] = 0x00;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			3, 0x21, 0x0002, 0x2001, &com_buff, 1);
+
+	/* Do not set fx returns to mono */
+	com_buff[0] = 0x00;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			3, 0x21, 0x0001, 0x2001, &com_buff, 1);
+
+	/* Mute the S/PDIF hardware loopback
+	 * same odd volume logic here as above
+	 */
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x80;
+	/* S/PDIF hardware input 1 left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0112, 0x4001, &com_buff, 2);
+	/* S/PDIF hardware input 1 right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0113, 0x4001, &com_buff, 2);
+	/* S/PDIF hardware input 2 left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0116, 0x4001, &com_buff, 2);
+	/* S/PDIF hardware input 2 right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0117, 0x4001, &com_buff, 2);
+	/* S/PDIF hardware input 3 left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x011a, 0x4001, &com_buff, 2);
+	/* S/PDIF hardware input 3 right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x011b, 0x4001, &com_buff, 2);
+	/* S/PDIF hardware input 4 left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x011e, 0x4001, &com_buff, 2);
+	/* S/PDIF hardware input 4 right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x011f, 0x4001, &com_buff, 2);
+	/* S/PDIF software return 1 left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0102, 0x4001, &com_buff, 2);
+	/* S/PDIF software return 1 right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0103, 0x4001, &com_buff, 2);
+	/* S/PDIF software return 2 left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0106, 0x4001, &com_buff, 2);
+	/* S/PDIF software return 2 right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0107, 0x4001, &com_buff, 2);
+
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x00;
+	/* S/PDIF software return 3 left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x010a, 0x4001, &com_buff, 2);
+
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x80;
+	/* S/PDIF software return 3 right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x010b, 0x4001, &com_buff, 2);
+	/* S/PDIF software return 4 left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x010e, 0x4001, &com_buff, 2);
+
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x00;
+	/* S/PDIF software return 4 right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x010f, 0x4001, &com_buff, 2);
+
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x80;
+	/* S/PDIF fx returns left channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0122, 0x4001, &com_buff, 2);
+	/* S/PDIF fx returns right channel */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0123, 0x4001, &com_buff, 2);
+
+	/* Set the dropdown "Effect" to the first option */
+	/* Room1  = 0x00 */
+	/* Room2  = 0x01 */
+	/* Room3  = 0x02 */
+	/* Hall 1 = 0x03 */
+	/* Hall 2 = 0x04 */
+	/* Plate  = 0x05 */
+	/* Delay  = 0x06 */
+	/* Echo   = 0x07 */
+	com_buff[0] = 0x00;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0200, 0x4301, &com_buff, 1);	/* max is 0xff */
+	/* min is 0x00 */
+
+
+	/* Set the effect duration to 0 */
+	/* max is 0xffff */
+	/* min is 0x0000 */
+	com_buff[0] = 0x00;
+	com_buff[1] = 0x00;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0400, 0x4301, &com_buff, 2);
+
+	/* Set the effect volume and feedback to 0 */
+	/* max is 0xff */
+	/* min is 0x00 */
+	com_buff[0] = 0x00;
+	/* feedback: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0500, 0x4301, &com_buff, 1);
+	/* volume: */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			1, 0x21, 0x0300, 0x4301, &com_buff, 1);
+
+	/* Set soft button hold duration */
+	/* 0x03 = 250ms */
+	/* 0x05 = 500ms DEFAULT */
+	/* 0x08 = 750ms */
+	/* 0x0a = 1sec */
+	com_buff[0] = 0x05;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			3, 0x21, 0x0005, 0x2001, &com_buff, 1);
+
+	/* Use dim LEDs for button of state */
+	com_buff[0] = 0x00;
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			3, 0x21, 0x0004, 0x2001, &com_buff, 1);
+}
+
+#define MBOX3_DESCRIPTOR_SIZE	464
+
+static int snd_usb_mbox3_boot_quirk(struct usb_device *dev)
+{
+	struct usb_host_config *config = dev->actconfig;
+	int err;
+	int descriptor_size;
+
+	descriptor_size = le16_to_cpu(get_cfg_desc(config)->wTotalLength);
+
+	if (descriptor_size != MBOX3_DESCRIPTOR_SIZE) {
+		dev_err(&dev->dev, "MBOX3: Invalid descriptor size=%d.\n", descriptor_size);
+		return -ENODEV;
+	}
+
+	dev_dbg(&dev->dev, "MBOX3: device initialised!\n");
+
+	struct usb_device_descriptor *new_device_descriptor __free(kfree) =
+		kmalloc_obj(*new_device_descriptor);
+	if (!new_device_descriptor)
+		return -ENOMEM;
+
+	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
+		new_device_descriptor, sizeof(*new_device_descriptor));
+	if (err < 0)
+		dev_dbg(&dev->dev, "MBOX3: error usb_get_descriptor: %d\n", err);
+	if (new_device_descriptor->bNumConfigurations > dev->descriptor.bNumConfigurations)
+		dev_dbg(&dev->dev, "MBOX3: error too large bNumConfigurations: %d\n",
+			new_device_descriptor->bNumConfigurations);
+	else
+		memcpy(&dev->descriptor, new_device_descriptor, sizeof(dev->descriptor));
+
+	err = usb_reset_configuration(dev);
+	if (err < 0)
+		dev_dbg(&dev->dev, "MBOX3: error usb_reset_configuration: %d\n", err);
+
+	dev_dbg(&dev->dev, "MBOX3: new boot length = %d\n",
+		le16_to_cpu(get_cfg_desc(config)->wTotalLength));
+
+	mbox3_setup_defaults(dev);
+	dev_info(&dev->dev, "MBOX3: Initialized.");
+
+	return 0; /* Successful boot */
+}
+
+#define MICROBOOK_BUF_SIZE 128
+
+static int snd_usb_motu_microbookii_communicate(struct usb_device *dev, u8 *buf,
+						int buf_size, int *length)
+{
+	int err, actual_length;
+
+	if (usb_pipe_type_check(dev, usb_sndintpipe(dev, 0x01)))
+		return -EINVAL;
+	err = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x01), buf, *length,
+				&actual_length, 1000);
+	if (err < 0)
+		return err;
+
+	print_hex_dump(KERN_DEBUG, "MicroBookII snd: ", DUMP_PREFIX_NONE, 16, 1,
+		       buf, actual_length, false);
+
+	memset(buf, 0, buf_size);
+
+	if (usb_pipe_type_check(dev, usb_rcvintpipe(dev, 0x82)))
+		return -EINVAL;
+	err = usb_interrupt_msg(dev, usb_rcvintpipe(dev, 0x82), buf, buf_size,
+				&actual_length, 1000);
+	if (err < 0)
+		return err;
+
+	print_hex_dump(KERN_DEBUG, "MicroBookII rcv: ", DUMP_PREFIX_NONE, 16, 1,
+		       buf, actual_length, false);
+
+	*length = actual_length;
+	return 0;
+}
+
+static int snd_usb_motu_microbookii_boot_quirk(struct usb_device *dev)
+{
+	int err, actual_length, poll_attempts = 0;
+	static const u8 set_samplerate_seq[] = { 0x00, 0x00, 0x00, 0x00,
+						 0x00, 0x00, 0x0b, 0x14,
+						 0x00, 0x00, 0x00, 0x01 };
+	static const u8 poll_ready_seq[] = { 0x00, 0x04, 0x00, 0x00,
+					     0x00, 0x00, 0x0b, 0x18 };
+	u8 *buf = kzalloc(MICROBOOK_BUF_SIZE, GFP_KERNEL);
+
+	if (!buf)
+		return -ENOMEM;
+
+	dev_info(&dev->dev, "Waiting for MOTU Microbook II to boot up...\n");
+
+	/* First we tell the device which sample rate to use. */
+	memcpy(buf, set_samplerate_seq, sizeof(set_samplerate_seq));
+	actual_length = sizeof(set_samplerate_seq);
+	err = snd_usb_motu_microbookii_communicate(dev, buf, MICROBOOK_BUF_SIZE,
+						   &actual_length);
+
+	if (err < 0) {
+		dev_err(&dev->dev,
+			"failed setting the sample rate for Motu MicroBook II: %d\n",
+			err);
+		goto free_buf;
+	}
+
+	/* Then we poll every 100 ms until the device informs of its readiness. */
+	while (true) {
+		if (++poll_attempts > 100) {
+			dev_err(&dev->dev,
+				"failed booting Motu MicroBook II: timeout\n");
+			err = -ENODEV;
+			goto free_buf;
+		}
+
+		memset(buf, 0, MICROBOOK_BUF_SIZE);
+		memcpy(buf, poll_ready_seq, sizeof(poll_ready_seq));
+
+		actual_length = sizeof(poll_ready_seq);
+		err = snd_usb_motu_microbookii_communicate(
+			dev, buf, MICROBOOK_BUF_SIZE, &actual_length);
+		if (err < 0) {
+			dev_err(&dev->dev,
+				"failed booting Motu MicroBook II: communication error %d\n",
+				err);
+			goto free_buf;
+		}
+
+		/* the device signals its readiness through a message of the
+		 * form
+		 *           XX 06 00 00 00 00 0b 18  00 00 00 01
+		 * If the device is not yet ready to accept audio data, the
+		 * last byte of that sequence is 00.
+		 */
+		if (actual_length == 12 && buf[actual_length - 1] == 1)
+			break;
+
+		msleep(100);
+	}
+
+	dev_info(&dev->dev, "MOTU MicroBook II ready\n");
+
+free_buf:
+	kfree(buf);
+	return err;
+}
+
+static int snd_usb_motu_m_series_boot_quirk(struct usb_device *dev)
+{
+	msleep(4000);
+
+	return 0;
+}
+
+static int snd_usb_rme_digiface_boot_quirk(struct usb_device *dev)
+{
+	/* Disable mixer, internal clock, all outputs ADAT, 48kHz, TMS off */
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			16, 0x40, 0x2410, 0x7fff, NULL, 0);
+	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+			18, 0x40, 0x0104, 0xffff, NULL, 0);
+
+	/* Disable loopback for all inputs */
+	for (int ch = 0; ch < 32; ch++)
+		snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+				22, 0x40, 0x400, ch, NULL, 0);
+
+	/* Unity gain for all outputs */
+	for (int ch = 0; ch < 34; ch++)
+		snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+				21, 0x40, 0x9000, 0x100 + ch, NULL, 0);
+
+	return 0;
+}
+
+/*
+ * Setup quirks
+ */
+#define MAUDIO_SET		0x01 /* parse device_setup */
+#define MAUDIO_SET_COMPATIBLE	0x80 /* use only "win-compatible" interfaces */
+#define MAUDIO_SET_DTS		0x02 /* enable DTS Digital Output */
+#define MAUDIO_SET_96K		0x04 /* 48-96kHz rate if set, 8-48kHz otherwise */
+#define MAUDIO_SET_24B		0x08 /* 24bits sample if set, 16bits otherwise */
+#define MAUDIO_SET_DI		0x10 /* enable Digital Input */
+#define MAUDIO_SET_MASK		0x1f /* bit mask for setup value */
+#define MAUDIO_SET_24B_48K_DI	 0x19 /* 24bits+48kHz+Digital Input */
+#define MAUDIO_SET_24B_48K_NOTDI 0x09 /* 24bits+48kHz+No Digital Input */
+#define MAUDIO_SET_16B_48K_DI	 0x11 /* 16bits+48kHz+Digital Input */
+#define MAUDIO_SET_16B_48K_NOTDI 0x01 /* 16bits+48kHz+No Digital Input */
+
+static int quattro_skip_setting_quirk(struct snd_usb_audio *chip,
+				      int iface, int altno)
+{
+	/* Reset ALL ifaces to 0 altsetting.
+	 * Call it for every possible altsetting of every interface.
+	 */
+	usb_set_interface(chip->dev, iface, 0);
+	if (chip->setup & MAUDIO_SET) {
+		if (chip->setup & MAUDIO_SET_COMPATIBLE) {
+			if (iface != 1 && iface != 2)
+				return 1; /* skip all interfaces but 1 and 2 */
+		} else {
+			unsigned int mask;
+			if (iface == 1 || iface == 2)
+				return 1; /* skip interfaces 1 and 2 */
+			if ((chip->setup & MAUDIO_SET_96K) && altno != 1)
+				return 1; /* skip this altsetting */
+			mask = chip->setup & MAUDIO_SET_MASK;
+			if (mask == MAUDIO_SET_24B_48K_DI && altno != 2)
+				return 1; /* skip this altsetting */
+			if (mask == MAUDIO_SET_24B_48K_NOTDI && altno != 3)
+				return 1; /* skip this altsetting */
+			if (mask == MAUDIO_SET_16B_48K_NOTDI && altno != 4)
+				return 1; /* skip this altsetting */
+		}
+	}
+	usb_audio_dbg(chip,
+		    "using altsetting %d for interface %d config %d\n",
+		    altno, iface, chip->setup);
+	return 0; /* keep this altsetting */
+}
+
+static int audiophile_skip_setting_quirk(struct snd_usb_audio *chip,
+					 int iface,
+					 int altno)
+{
+	/* Reset ALL ifaces to 0 altsetting.
+	 * Call it for every possible altsetting of every interface.
+	 */
+	usb_set_interface(chip->dev, iface, 0);
+
+	if (chip->setup & MAUDIO_SET) {
+		unsigned int mask;
+		if ((chip->setup & MAUDIO_SET_DTS) && altno != 6)
+			return 1; /* skip this altsetting */
+		if ((chip->setup & MAUDIO_SET_96K) && altno != 1)
+			return 1; /* skip this altsetting */
+		mask = chip->setup & MAUDIO_SET_MASK;
+		if (mask == MAUDIO_SET_24B_48K_DI && altno != 2)
+			return 1; /* skip this altsetting */
+		if (mask == MAUDIO_SET_24B_48K_NOTDI && altno != 3)
+			return 1; /* skip this altsetting */
+		if (mask == MAUDIO_SET_16B_48K_DI && altno != 4)
+			return 1; /* skip this altsetting */
+		if (mask == MAUDIO_SET_16B_48K_NOTDI && altno != 5)
+			return 1; /* skip this altsetting */
+	}
+
+	return 0; /* keep this altsetting */
+}
+
+static int fasttrackpro_skip_setting_quirk(struct snd_usb_audio *chip,
+					   int iface, int altno)
+{
+	/* Reset ALL ifaces to 0 altsetting.
+	 * Call it for every possible altsetting of every interface.
+	 */
+	usb_set_interface(chip->dev, iface, 0);
+
+	/* possible configuration where both inputs and only one output is
+	 *used is not supported by the current setup
+	 */
+	if (chip->setup & (MAUDIO_SET | MAUDIO_SET_24B)) {
+		if (chip->setup & MAUDIO_SET_96K) {
+			if (altno != 3 && altno != 6)
+				return 1;
+		} else if (chip->setup & MAUDIO_SET_DI) {
+			if (iface == 4)
+				return 1; /* no analog input */
+			if (altno != 2 && altno != 5)
+				return 1; /* enable only altsets 2 and 5 */
+		} else {
+			if (iface == 5)
+				return 1; /* disable digialt input */
+			if (altno != 2 && altno != 5)
+				return 1; /* enalbe only altsets 2 and 5 */
+		}
+	} else {
+		/* keep only 16-Bit mode */
+		if (altno != 1)
+			return 1;
+	}
+
+	usb_audio_dbg(chip,
+		    "using altsetting %d for interface %d config %d\n",
+		    altno, iface, chip->setup);
+	return 0; /* keep this altsetting */
+}
+
+static int s1810c_skip_setting_quirk(struct snd_usb_audio *chip,
+					   int iface, int altno)
+{
+	/*
+	 * Altno settings:
+	 *
+	 * Playback (Interface 1):
+	 * 1: 6 Analog + 2 S/PDIF
+	 * 2: 6 Analog + 2 S/PDIF
+	 * 3: 6 Analog
+	 *
+	 * Capture (Interface 2):
+	 * 1: 8 Analog + 2 S/PDIF + 8 ADAT
+	 * 2: 8 Analog + 2 S/PDIF + 4 ADAT
+	 * 3: 8 Analog
+	 */
+
+	/*
+	 * I'll leave 2 as the default one and
+	 * use device_setup to switch to the
+	 * other two.
+	 */
+	if ((chip->setup == 0 || chip->setup > 2) && altno != 2)
+		return 1;
+	else if (chip->setup == 1 && altno != 1)
+		return 1;
+	else if (chip->setup == 2 && altno != 3)
+		return 1;
+
+	return 0;
+}
+
+int snd_usb_apply_interface_quirk(struct snd_usb_audio *chip,
+				  int iface,
+				  int altno)
+{
+	/* audiophile usb: skip altsets incompatible with device_setup */
+	if (chip->usb_id == USB_ID(0x0763, 0x2003))
+		return audiophile_skip_setting_quirk(chip, iface, altno);
+	/* quattro usb: skip altsets incompatible with device_setup */
+	if (chip->usb_id == USB_ID(0x0763, 0x2001))
+		return quattro_skip_setting_quirk(chip, iface, altno);
+	/* fasttrackpro usb: skip altsets incompatible with device_setup */
+	if (chip->usb_id == USB_ID(0x0763, 0x2012))
+		return fasttrackpro_skip_setting_quirk(chip, iface, altno);
+	/* presonus studio 1810c: skip altsets incompatible with device_setup */
+	if (chip->usb_id == USB_ID(0x194f, 0x010c))
+		return s1810c_skip_setting_quirk(chip, iface, altno);
+
+	return 0;
+}
+
+int snd_usb_apply_boot_quirk(struct usb_device *dev,
+			     struct usb_interface *intf,
+			     const struct snd_usb_audio_quirk *quirk,
+			     unsigned int id)
+{
+	switch (id) {
+	case USB_ID(0x041e, 0x3000):
+		/* SB Extigy needs special boot-up sequence */
+		/* if more models come, this will go to the quirk list. */
+		return snd_usb_extigy_boot_quirk(dev, intf);
+
+	case USB_ID(0x041e, 0x3020):
+		/* SB Audigy 2 NX needs its own boot-up magic, too */
+		return snd_usb_audigy2nx_boot_quirk(dev);
+
+	case USB_ID(0x10f5, 0x0200):
+		/* C-Media CM106 / Turtle Beach Audio Advantage Roadie */
+		return snd_usb_cm106_boot_quirk(dev);
+
+	case USB_ID(0x0d8c, 0x0102):
+		/* C-Media CM6206 / CM106-Like Sound Device */
+	case USB_ID(0x0ccd, 0x00b1): /* Terratec Aureon 7.1 USB */
+		return snd_usb_cm6206_boot_quirk(dev);
+
+	case USB_ID(0x0dba, 0x3000):
+		/* Digidesign Mbox 2 */
+		return snd_usb_mbox2_boot_quirk(dev);
+	case USB_ID(0x0dba, 0x5000):
+		/* Digidesign Mbox 3 */
+		return snd_usb_mbox3_boot_quirk(dev);
+
+
+	case USB_ID(0x1235, 0x0010): /* Focusrite Novation Saffire 6 USB */
+	case USB_ID(0x1235, 0x0018): /* Focusrite Novation Twitch */
+		return snd_usb_novation_boot_quirk(dev);
+
+	case USB_ID(0x133e, 0x0815):
+		/* Access Music VirusTI Desktop */
+		return snd_usb_accessmusic_boot_quirk(dev);
+
+	case USB_ID(0x17cc, 0x1000): /* Komplete Audio 6 */
+	case USB_ID(0x17cc, 0x1010): /* Traktor Audio 6 */
+	case USB_ID(0x17cc, 0x1020): /* Traktor Audio 10 */
+		return snd_usb_nativeinstruments_boot_quirk(dev);
+	case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
+		return snd_usb_fasttrackpro_boot_quirk(dev);
+	case USB_ID(0x047f, 0xc010): /* Plantronics Gamecom 780 */
+		return snd_usb_gamecon780_boot_quirk(dev);
+	case USB_ID(0x2466, 0x8010): /* Fractal Audio Axe-Fx 3 */
+		return snd_usb_axefx3_boot_quirk(dev);
+	case USB_ID(0x07fd, 0x0004): /* MOTU MicroBook II */
+		/*
+		 * For some reason interface 3 with vendor-spec class is
+		 * detected on MicroBook IIc.
+		 */
+		if (get_iface_desc(intf->altsetting)->bInterfaceClass ==
+		    USB_CLASS_VENDOR_SPEC &&
+		    get_iface_desc(intf->altsetting)->bInterfaceNumber < 3)
+			return snd_usb_motu_microbookii_boot_quirk(dev);
+		break;
+	case USB_ID(0x2a39, 0x3f8c): /* RME Digiface USB */
+	case USB_ID(0x2a39, 0x3fa0): /* RME Digiface USB (alternate) */
+		return snd_usb_rme_digiface_boot_quirk(dev);
+	}
+
+	return 0;
+}
+
+int snd_usb_apply_boot_quirk_once(struct usb_device *dev,
+				  struct usb_interface *intf,
+				  const struct snd_usb_audio_quirk *quirk,
+				  unsigned int id)
+{
+	switch (id) {
+	case USB_ID(0x07fd, 0x0008): /* MOTU M Series, 1st hardware version */
+		return snd_usb_motu_m_series_boot_quirk(dev);
+	}
+
+	/* Behringer devices may need explicit device descriptor read at boot */
+	if (USB_ID_VENDOR(id) == 0x1397)
+		return snd_usb_cm1a_boot_quirk(dev);
+
+	return 0;
+}
+
+/*
+ * check if the device uses big-endian samples
+ */
+int snd_usb_is_big_endian_format(struct snd_usb_audio *chip,
+				 const struct audioformat *fp)
+{
+	/* it depends on altsetting whether the device is big-endian or not */
+	switch (chip->usb_id) {
+	case USB_ID(0x0763, 0x2001): /* M-Audio Quattro: captured data only */
+		if (fp->altsetting == 2 || fp->altsetting == 3 ||
+			fp->altsetting == 5 || fp->altsetting == 6)
+			return 1;
+		break;
+	case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
+		if (chip->setup == 0x00 ||
+			fp->altsetting == 1 || fp->altsetting == 2 ||
+			fp->altsetting == 3)
+			return 1;
+		break;
+	case USB_ID(0x0763, 0x2012): /* M-Audio Fast Track Pro */
+		if (fp->altsetting == 2 || fp->altsetting == 3 ||
+			fp->altsetting == 5 || fp->altsetting == 6)
+			return 1;
+		break;
+	}
+	return 0;
+}
+
+/*
+ * For E-Mu 0404USB/0202USB/TrackerPre/0204 sample rate should be set for device,
+ * not for interface.
+ */
+
+enum {
+	EMU_QUIRK_SR_44100HZ = 0,
+	EMU_QUIRK_SR_48000HZ,
+	EMU_QUIRK_SR_88200HZ,
+	EMU_QUIRK_SR_96000HZ,
+	EMU_QUIRK_SR_176400HZ,
+	EMU_QUIRK_SR_192000HZ
+};
+
+static void set_format_emu_quirk(struct snd_usb_substream *subs,
+				 const struct audioformat *fmt)
+{
+	unsigned char emu_samplerate_id = 0;
+
+	/* When capture is active
+	 * sample rate shouldn't be changed
+	 * by playback substream
+	 */
+	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
+		if (subs->stream->substream[SNDRV_PCM_STREAM_CAPTURE].cur_audiofmt)
+			return;
+	}
+
+	switch (fmt->rate_min) {
+	case 48000:
+		emu_samplerate_id = EMU_QUIRK_SR_48000HZ;
+		break;
+	case 88200:
+		emu_samplerate_id = EMU_QUIRK_SR_88200HZ;
+		break;
+	case 96000:
+		emu_samplerate_id = EMU_QUIRK_SR_96000HZ;
+		break;
+	case 176400:
+		emu_samplerate_id = EMU_QUIRK_SR_176400HZ;
+		break;
+	case 192000:
+		emu_samplerate_id = EMU_QUIRK_SR_192000HZ;
+		break;
+	default:
+		emu_samplerate_id = EMU_QUIRK_SR_44100HZ;
+		break;
+	}
+	snd_emuusb_set_samplerate(subs->stream->chip, emu_samplerate_id);
+	subs->pkt_offset_adj = (emu_samplerate_id >= EMU_QUIRK_SR_176400HZ) ? 4 : 0;
+}
+
+static int pioneer_djm_set_format_quirk(struct snd_usb_substream *subs,
+					u16 windex)
+{
+	unsigned int cur_rate = subs->data_endpoint->cur_rate;
+	u8 sr[3];
+	// Convert to little endian
+	sr[0] = cur_rate & 0xff;
+	sr[1] = (cur_rate >> 8) & 0xff;
+	sr[2] = (cur_rate >> 16) & 0xff;
+	usb_set_interface(subs->dev, 0, 1);
+	// we should derive windex from fmt-sync_ep but it's not set
+	snd_usb_ctl_msg(subs->stream->chip->dev,
+		usb_sndctrlpipe(subs->stream->chip->dev, 0),
+		0x01, 0x22, 0x0100, windex, &sr, 0x0003);
+	return 0;
+}
+
+static void mbox3_set_format_quirk(struct snd_usb_substream *subs,
+				const struct audioformat *fmt)
+{
+	__le32 buff4 = 0;
+	u8 buff1 = 0x01;
+	u32 new_rate = subs->data_endpoint->cur_rate;
+	u32 current_rate;
+
+	// Get current rate from card and check if changing it is needed
+	snd_usb_ctl_msg(subs->dev, usb_rcvctrlpipe(subs->dev, 0),
+					0x01, 0x21 | USB_DIR_IN, 0x0100, 0x8101, &buff4, 4);
+	current_rate = le32_to_cpu(buff4);
+	dev_dbg(&subs->dev->dev,
+			 "MBOX3: Current configured sample rate: %d", current_rate);
+	if (current_rate == new_rate) {
+		dev_dbg(&subs->dev->dev,
+			"MBOX3: No change needed (current rate:%d == new rate:%d)",
+			current_rate, new_rate);
+		return;
+	}
+
+	// Set new rate
+	dev_info(&subs->dev->dev,
+			 "MBOX3: Changing sample rate to: %d", new_rate);
+	buff4 = cpu_to_le32(new_rate);
+	snd_usb_ctl_msg(subs->dev, usb_sndctrlpipe(subs->dev, 0),
+					0x01, 0x21, 0x0100, 0x8101, &buff4, 4);
+
+	// Set clock source to Internal
+	snd_usb_ctl_msg(subs->dev, usb_sndctrlpipe(subs->dev, 0),
+					0x01, 0x21, 0x0100, 0x8001, &buff1, 1);
+
+	// Check whether the change was successful
+	buff4 = 0;
+	snd_usb_ctl_msg(subs->dev, usb_rcvctrlpipe(subs->dev, 0),
+					0x01, 0x21 | USB_DIR_IN, 0x0100, 0x8101, &buff4, 4);
+	if (new_rate != le32_to_cpu(buff4))
+		dev_warn(&subs->dev->dev, "MBOX3: Couldn't set the sample rate");
+}
+
+static const int rme_digiface_rate_table[] = {
+	32000, 44100, 48000, 0,
+	64000, 88200, 96000, 0,
+	128000, 176400, 192000, 0,
+};
+
+static int rme_digiface_set_format_quirk(struct snd_usb_substream *subs)
+{
+	unsigned int cur_rate = subs->data_endpoint->cur_rate;
+	u16 val;
+	int speed_mode;
+	int id;
+
+	for (id = 0; id < ARRAY_SIZE(rme_digiface_rate_table); id++) {
+		if (rme_digiface_rate_table[id] == cur_rate)
+			break;
+	}
+
+	if (id >= ARRAY_SIZE(rme_digiface_rate_table))
+		return -EINVAL;
+
+	/* 2, 3, 4 for 1x, 2x, 4x */
+	speed_mode = (id >> 2) + 2;
+	val = (id << 3) | (speed_mode << 12);
+
+	/* Set the sample rate */
+	snd_usb_ctl_msg(subs->stream->chip->dev,
+		usb_sndctrlpipe(subs->stream->chip->dev, 0),
+		16, 0x40, val, 0x7078, NULL, 0);
+	return 0;
+}
+
+void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
+			      const struct audioformat *fmt)
+{
+	switch (subs->stream->chip->usb_id) {
+	case USB_ID(0x041e, 0x3f02): /* E-Mu 0202 USB */
+	case USB_ID(0x041e, 0x3f04): /* E-Mu 0404 USB */
+	case USB_ID(0x041e, 0x3f0a): /* E-Mu Tracker Pre */
+	case USB_ID(0x041e, 0x3f19): /* E-Mu 0204 USB */
+		set_format_emu_quirk(subs, fmt);
+		break;
+	case USB_ID(0x534d, 0x0021): /* MacroSilicon MS2100/MS2106 */
+	case USB_ID(0x534d, 0x2109): /* MacroSilicon MS2109 */
+		subs->stream_offset_adj = 2;
+		break;
+	case USB_ID(0x2b73, 0x000a): /* Pioneer DJM-900NXS2 */
+	case USB_ID(0x2b73, 0x0013): /* Pioneer DJM-450 */
+	case USB_ID(0x2b73, 0x0034): /* Pioneer DJM-V10 */
+		pioneer_djm_set_format_quirk(subs, 0x0082);
+		break;
+	case USB_ID(0x08e4, 0x017f): /* Pioneer DJM-750 */
+	case USB_ID(0x08e4, 0x0163): /* Pioneer DJM-850 */
+		pioneer_djm_set_format_quirk(subs, 0x0086);
+		break;
+	case USB_ID(0x0dba, 0x5000):
+		mbox3_set_format_quirk(subs, fmt); /* Digidesign Mbox 3 */
+		break;
+	case USB_ID(0x2a39, 0x3f8c): /* RME Digiface USB */
+	case USB_ID(0x2a39, 0x3fa0): /* RME Digiface USB (alternate) */
+		rme_digiface_set_format_quirk(subs);
+		break;
+	}
+}
+
+int snd_usb_select_mode_quirk(struct snd_usb_audio *chip,
+			      const struct audioformat *fmt)
+{
+	struct usb_device *dev = chip->dev;
+	int err;
+
+	if (chip->quirk_flags & QUIRK_FLAG_ITF_USB_DSD_DAC) {
+		/* First switch to alt set 0, otherwise the mode switch cmd
+		 * will not be accepted by the DAC
+		 */
+		err = usb_set_interface(dev, fmt->iface, 0);
+		if (err < 0)
+			return err;
+
+		msleep(20); /* Delay needed after setting the interface */
+
+		/* Vendor mode switch cmd is required. */
+		if (fmt->formats & SNDRV_PCM_FMTBIT_DSD_U32_BE) {
+			/* DSD mode (DSD_U32) requested */
+			err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
+					      USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+					      1, 1, NULL, 0);
+			if (err < 0)
+				return err;
+
+		} else {
+			/* PCM or DOP mode (S32) requested */
+			/* PCM mode (S16) requested */
+			err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
+					      USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+					      0, 1, NULL, 0);
+			if (err < 0)
+				return err;
+
+		}
+		msleep(20);
+	}
+	return 0;
+}
+
+void snd_usb_endpoint_start_quirk(struct snd_usb_endpoint *ep)
+{
+	/*
+	 * "Playback Design" products send bogus feedback data at the start
+	 * of the stream. Ignore them.
+	 */
+	if (USB_ID_VENDOR(ep->chip->usb_id) == 0x23ba &&
+	    ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
+		ep->skip_packets = 4;
+
+	/*
+	 * M-Audio Fast Track C400/C600 - when packets are not skipped, real
+	 * world latency varies by approx. +/- 50 frames (at 96kHz) each time
+	 * the stream is (re)started. When skipping packets 16 at endpoint
+	 * start up, the real world latency is stable within +/- 1 frame (also
+	 * across power cycles).
+	 */
+	if ((ep->chip->usb_id == USB_ID(0x0763, 0x2030) ||
+	     ep->chip->usb_id == USB_ID(0x0763, 0x2031)) &&
+	    ep->type == SND_USB_ENDPOINT_TYPE_DATA)
+		ep->skip_packets = 16;
+
+	/* Work around devices that report unreasonable feedback data */
+	if ((ep->chip->usb_id == USB_ID(0x0644, 0x8038) ||  /* TEAC UD-H01 */
+	     ep->chip->usb_id == USB_ID(0x1852, 0x5034)) && /* T+A Dac8 */
+	    ep->syncmaxsize == 4)
+		ep->tenor_fb_quirk = 1;
+}
+
+/* quirk applied after snd_usb_ctl_msg(); not applied during boot quirks */
+void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
+			   __u8 request, __u8 requesttype, __u16 value,
+			   __u16 index, void *data, __u16 size)
+{
+	struct snd_usb_audio *chip = dev_get_drvdata(&dev->dev);
+
+	if (!chip || (requesttype & USB_TYPE_MASK) != USB_TYPE_CLASS)
+		return;
+
+	if (chip->quirk_flags & QUIRK_FLAG_CTL_MSG_DELAY)
+		msleep(20);
+	else if (chip->quirk_flags & QUIRK_FLAG_CTL_MSG_DELAY_1M)
+		usleep_range(1000, 2000);
+	else if (chip->quirk_flags & QUIRK_FLAG_CTL_MSG_DELAY_5M)
+		usleep_range(5000, 6000);
+}
+
+/*
+ * snd_usb_interface_dsd_format_quirks() is called from format.c to
+ * augment the PCM format bit-field for DSD types. The UAC standards
+ * don't have a designated bit field to denote DSD-capable interfaces,
+ * hence all hardware that is known to support this format has to be
+ * listed here.
+ */
+u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
+					struct audioformat *fp,
+					unsigned int sample_bytes)
+{
+	struct usb_interface *iface;
+
+	/* Playback Designs */
+	if (USB_ID_VENDOR(chip->usb_id) == 0x23ba &&
+	    USB_ID_PRODUCT(chip->usb_id) < 0x0110) {
+		switch (fp->altsetting) {
+		case 1:
+			fp->dsd_dop = true;
+			return SNDRV_PCM_FMTBIT_DSD_U16_LE;
+		case 2:
+			fp->dsd_bitrev = true;
+			return SNDRV_PCM_FMTBIT_DSD_U8;
+		case 3:
+			fp->dsd_bitrev = true;
+			return SNDRV_PCM_FMTBIT_DSD_U16_LE;
+		}
+	}
+
+	/* XMOS based USB DACs */
+	switch (chip->usb_id) {
+	case USB_ID(0x139f, 0x5504): /* Nagra DAC */
+	case USB_ID(0x20b1, 0x3089): /* Mola-Mola DAC */
+	case USB_ID(0x2522, 0x0007): /* LH Labs Geek Out 1V5 */
+	case USB_ID(0x2522, 0x0009): /* LH Labs Geek Pulse X Inifinity 2V0 */
+	case USB_ID(0x2522, 0x0012): /* LH Labs VI DAC Infinity */
+	case USB_ID(0x2772, 0x0230): /* Pro-Ject Pre Box S2 Digital */
+		if (fp->altsetting == 2)
+			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+		break;
+
+	case USB_ID(0x0d8c, 0x0316): /* Hegel HD12 DSD */
+	case USB_ID(0x10cb, 0x0103): /* The Bit Opus #3; with fp->dsd_raw */
+	case USB_ID(0x16d0, 0x06b2): /* NuPrime DAC-10 */
+	case USB_ID(0x16d0, 0x06b4): /* NuPrime Audio HD-AVP/AVA */
+	case USB_ID(0x16d0, 0x0733): /* Furutech ADL Stratos */
+	case USB_ID(0x16d0, 0x09d8): /* NuPrime IDA-8 */
+	case USB_ID(0x16d0, 0x09db): /* NuPrime Audio DAC-9 */
+	case USB_ID(0x16d0, 0x09dd): /* Encore mDSD */
+	case USB_ID(0x16d0, 0x0ab1): /* PureAudio APA DAC */
+	case USB_ID(0x16d0, 0xeca1): /* PureAudio Lotus DAC5, DAC5 SE, DAC5 Pro */
+	case USB_ID(0x1db5, 0x0003): /* Bryston BDA3 */
+	case USB_ID(0x20a0, 0x4143): /* WaveIO USB Audio 2.0 */
+	case USB_ID(0x22e1, 0xca01): /* HDTA Serenade DSD */
+	case USB_ID(0x249c, 0x9326): /* M2Tech Young MkIII */
+	case USB_ID(0x2616, 0x0106): /* PS Audio NuWave DAC */
+	case USB_ID(0x2622, 0x0041): /* Audiolab M-DAC+ */
+	case USB_ID(0x2622, 0x0061): /* LEAK Stereo 230 */
+	case USB_ID(0x278b, 0x5100): /* Rotel RC-1590 */
+	case USB_ID(0x27f7, 0x3002): /* W4S DAC-2v2SE */
+	case USB_ID(0x29a2, 0x0086): /* Mutec MC3+ USB */
+	case USB_ID(0x6b42, 0x0042): /* MSB Technology */
+		if (fp->altsetting == 3)
+			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+		break;
+
+	/* Amanero Combo384 USB based DACs with native DSD support */
+	case USB_ID(0x16d0, 0x071a):  /* Amanero - Combo384 */
+		if (fp->altsetting == 2) {
+			switch (le16_to_cpu(chip->dev->descriptor.bcdDevice)) {
+			case 0x199:
+				return SNDRV_PCM_FMTBIT_DSD_U32_LE;
+			case 0x19b:
+			case 0x203:
+				return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+			default:
+				break;
+			}
+		}
+		break;
+	case USB_ID(0x16d0, 0x0a23):
+		if (fp->altsetting == 2)
+			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+		break;
+
+	default:
+		break;
+	}
+
+	/* ITF-USB DSD based DACs */
+	if (chip->quirk_flags & QUIRK_FLAG_ITF_USB_DSD_DAC) {
+		iface = usb_ifnum_to_if(chip->dev, fp->iface);
+
+		/* Altsetting 2 support native DSD if the num of altsets is
+		 * three (0-2),
+		 * Altsetting 3 support native DSD if the num of altsets is
+		 * four (0-3).
+		 */
+		if (fp->altsetting == iface->num_altsetting - 1)
+			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+	}
+
+	/* Mostly generic method to detect many DSD-capable implementations */
+	if ((chip->quirk_flags & QUIRK_FLAG_DSD_RAW) && fp->dsd_raw)
+		return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+
+	return 0;
+}
+
+void snd_usb_audioformat_attributes_quirk(struct snd_usb_audio *chip,
+					  struct audioformat *fp,
+					  int stream)
+{
+	switch (chip->usb_id) {
+	case USB_ID(0x0a92, 0x0053): /* AudioTrak Optoplay */
+		/* Optoplay sets the sample rate attribute although
+		 * it seems not supporting it in fact.
+		 */
+		fp->attributes &= ~UAC_EP_CS_ATTR_SAMPLE_RATE;
+		break;
+	case USB_ID(0x041e, 0x3020): /* Creative SB Audigy 2 NX */
+	case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
+		/* doesn't set the sample rate attribute, but supports it */
+		fp->attributes |= UAC_EP_CS_ATTR_SAMPLE_RATE;
+		break;
+	case USB_ID(0x0763, 0x2001):  /* M-Audio Quattro USB */
+	case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
+	case USB_ID(0x047f, 0x0ca1): /* plantronics headset */
+	case USB_ID(0x077d, 0x07af): /* Griffin iMic (note that there is
+					an older model 77d:223) */
+	/*
+	 * plantronics headset and Griffin iMic have set adaptive-in
+	 * although it's really not...
+	 */
+		fp->ep_attr &= ~USB_ENDPOINT_SYNCTYPE;
+		if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+			fp->ep_attr |= USB_ENDPOINT_SYNC_ADAPTIVE;
+		else
+			fp->ep_attr |= USB_ENDPOINT_SYNC_SYNC;
+		break;
+	case USB_ID(0x07fd, 0x0004):  /* MOTU MicroBook IIc */
+		/*
+		 * MaxPacketsOnly attribute is erroneously set in endpoint
+		 * descriptors. As a result this card produces noise with
+		 * all sample rates other than 96 kHz.
+		 */
+		fp->attributes &= ~UAC_EP_CS_ATTR_FILL_MAX;
+		break;
+	case USB_ID(0x1224, 0x2a25):  /* Jieli Technology USB PHY 2.0 */
+		/* mic works only when ep packet size is set to wMaxPacketSize */
+		fp->attributes |= UAC_EP_CS_ATTR_FILL_MAX;
+		break;
+	case USB_ID(0x3511, 0x2b1e): /* Opencomm2 UC USB Bluetooth dongle */
+		/* mic works only when ep pitch control is not set */
+		if (stream == SNDRV_PCM_STREAM_CAPTURE)
+			fp->attributes &= ~UAC_EP_CS_ATTR_PITCH_CONTROL;
+		break;
+	}
+}
+
+/*
+ * driver behavior quirk flags
+ */
+struct usb_string_match {
+	const char *manufacturer;
+	const char *product;
+};
+
+struct usb_audio_quirk_flags_table {
+	u32 id;
+	u64 flags;
+	const struct usb_string_match *usb_string_match;
+};
+
+#define DEVICE_FLG(vid, pid, _flags) \
+	{ .id = USB_ID(vid, pid), .flags = (_flags) }
+#define VENDOR_FLG(vid, _flags) DEVICE_FLG(vid, 0, _flags)
+
+/*
+ * Use as a last resort if using DEVICE_FLG() is prone to VID/PID conflicts.
+ *
+ * Usage:
+ *   // match vid, pid, "manufacturer", and "product"
+ *   DEVICE_STRING_FLG(vid, pid, "manufacturer", "product", flags)
+ *
+ *   // match vid, pid, "manufacturer", and any product string
+ *   DEVICE_STRING_FLG(vid, pid, "manufacturer", NULL,      flags)
+ *
+ *   // match vid, pid, "manufacturer", and device must have no product string
+ *   DEVICE_STRING_FLG(vid, pid, "manufacturer", "",        flags)
+ *
+ *   // match vid, pid, any manufacturer string, and "product"
+ *   DEVICE_STRING_FLG(vid, pid, NULL,           "product", flags)
+ *
+ *   // match vid, pid, no manufacturer string, and "product"
+ *   DEVICE_STRING_FLG(vid, pid, "",             "product", flags)
+ *
+ *   // match vid, pid, no manufacturer string, and no product string
+ *   DEVICE_STRING_FLG(vid, pid, "",             "",        flags)
+ */
+#define DEVICE_STRING_FLG(vid, pid, _manufacturer, _product, _flags)	\
+{									\
+	.id = USB_ID(vid, pid),						\
+	.usb_string_match = &(const struct usb_string_match) {		\
+		.manufacturer = _manufacturer,				\
+		.product = _product,					\
+	},								\
+	.flags = (_flags),						\
+}
+
+/*
+ * Use as a last resort if using VENDOR_FLG() is prone to VID conflicts.
+ *
+ * Usage:
+ *   // match vid, and "manufacturer"
+ *   VENDOR_STRING_FLG(vid, "manufacturer", flags)
+ *
+ *   // match vid, and device must have no manufacturer string
+ *   VENDOR_STRING_FLG(vid, "",             flags)
+ */
+#define VENDOR_STRING_FLG(vid, _manufacturer, _flags)			\
+	DEVICE_STRING_FLG(vid, 0, _manufacturer, NULL, _flags)
+
+static const struct usb_audio_quirk_flags_table quirk_flags_table[] = {
+	/* Device and string descriptor matches */
+	DEVICE_STRING_FLG(0x05ac, 0x110b, /* VID conflicts with Apple */
+			  "JKY Technology", NULL, /* Q2A */
+			  QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+
+	/* Device matches */
+	DEVICE_FLG(0x001f, 0x0b21, /* AB13X USB Audio */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x001f, 0x0b23, /* AB17X USB Audio */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x0020, 0x0b21, /* GHW-123P */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x0124, 0x0c21, /* Generic USB Headphone */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x03f0, 0x654a, /* HP 320 FHD Webcam */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_MIC_RES_16),
+	DEVICE_FLG(0x041e, 0x3000, /* Creative SB Extigy */
+		   QUIRK_FLAG_IGNORE_CTL_ERROR),
+	DEVICE_FLG(0x041e, 0x324d, /* Creative Sound Blaster Play! 3 */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x041e, 0x4080, /* Creative Live Cam VF0610 */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x045e, 0x083c, /* MS USB Link headset */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_CTL_MSG_DELAY |
+		   QUIRK_FLAG_DISABLE_AUTOSUSPEND),
+	DEVICE_FLG(0x045e, 0x070f, /* MS LifeChat LX-3000 Headset */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x046d, 0x0807, /* Logitech Webcam C500 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x0808, /* Logitech Webcam C600 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x0809,
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x0819, /* Logitech Webcam C210 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x081b, /* HD Webcam c310 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x081d, /* HD Webcam c510 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x0825, /* HD Webcam c270 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x0826, /* HD Webcam c525 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x084c, /* Logitech ConferenceCam Connect */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x046d, 0x08ca, /* Logitech Quickcam Fusion */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x0991, /* Logitech QuickCam Pro */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_IGNORE_CTL_ERROR |
+		   QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x09a2, /* QuickCam Communicate Deluxe/S7500 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIC_RES_384),
+	DEVICE_FLG(0x046d, 0x09a4, /* Logitech QuickCam E 3500 */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_IGNORE_CTL_ERROR),
+	DEVICE_FLG(0x046d, 0x0a8f, /* Logitech H390 headset */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M |
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x046d, 0x0aba, /* Logitech PRO X Wireless */
+		   QUIRK_FLAG_MIXER_GET_CUR_OK |
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x0499, 0x1506, /* Yamaha THR5 */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x0499, 0x1509, /* Steinberg UR22 */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x0499, 0x3108, /* Yamaha YIT-W12TX */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x04d8, 0xfeea, /* Benchmark DAC1 Pre */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x04e8, 0xa051, /* Samsung USBC Headset (AKG) */
+		   QUIRK_FLAG_SKIP_CLOCK_SELECTOR | QUIRK_FLAG_CTL_MSG_DELAY_5M),
+	DEVICE_FLG(0x0525, 0xa4ad, /* Hamedal C20 usb camero */
+		   QUIRK_FLAG_IFACE_SKIP_CLOSE),
+	DEVICE_FLG(0x054c, 0x0b8c, /* Sony WALKMAN NW-A45 DAC */
+		   QUIRK_FLAG_SET_IFACE_FIRST),
+	DEVICE_FLG(0x0556, 0x0014, /* Phoenix Audio TMX320VC */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x0572, 0x1b08, /* Conexant Systems (Rockwell), Inc. */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x0572, 0x1b09, /* Conexant Systems (Rockwell), Inc. */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x05a3, 0x9420, /* ELP HD USB Camera */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x05a7, 0x1020, /* Bose Companion 5 */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x05e1, 0x0408, /* Syntek STK1160 */
+		   QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x05e1, 0x0480, /* Hauppauge Woodbury */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x05fc, 0x0231, /* JBL Pebbles */
+		   QUIRK_FLAG_MIXER_PLAYBACK_LINEAR_VOL | QUIRK_FLAG_MIXER_CAPTURE_LINEAR_VOL |
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x0624, 0x3d3f, /* AB13X USB Audio */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x0644, 0x8043, /* TEAC UD-501/UD-501V2/UD-503/NT-503 */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY |
+		   QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x0644, 0x8044, /* Esoteric D-05X */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY |
+		   QUIRK_FLAG_IFACE_DELAY | QUIRK_FLAG_FORCE_IFACE_RESET),
+	DEVICE_FLG(0x0644, 0x804a, /* TEAC UD-301 */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY |
+		   QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x0644, 0x805f, /* TEAC Model 12 */
+		   QUIRK_FLAG_FORCE_IFACE_RESET),
+	DEVICE_FLG(0x0644, 0x806b, /* TEAC UD-701 */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY |
+		   QUIRK_FLAG_IFACE_DELAY | QUIRK_FLAG_FORCE_IFACE_RESET),
+	DEVICE_FLG(0x0644, 0x807d, /* TEAC UD-507 */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY |
+		   QUIRK_FLAG_IFACE_DELAY | QUIRK_FLAG_FORCE_IFACE_RESET),
+	DEVICE_FLG(0x0644, 0x806c, /* Esoteric XD */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY |
+		   QUIRK_FLAG_IFACE_DELAY | QUIRK_FLAG_FORCE_IFACE_RESET),
+	DEVICE_FLG(0x0661, 0x0883, /* iBasso DC04 Ultra */
+		   QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x0666, 0x0880, /* SPACETOUCH USB Audio */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY |
+		   QUIRK_FLAG_CTL_MSG_DELAY_5M),
+	DEVICE_FLG(0x06f8, 0xb000, /* Hercules DJ Console (Windows Edition) */
+		   QUIRK_FLAG_IGNORE_CTL_ERROR),
+	DEVICE_FLG(0x06f8, 0xd002, /* Hercules DJ Console (Macintosh Edition) */
+		   QUIRK_FLAG_IGNORE_CTL_ERROR),
+	DEVICE_FLG(0x0711, 0x5800, /* MCT Trigger 5 USB-to-HDMI */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x074d, 0x3553, /* Outlaw RR2150 (Micronas UAC3553B) */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x0763, 0x2030, /* M-Audio Fast Track C400 */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x0763, 0x2031, /* M-Audio Fast Track C600 */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x0763, 0x2080, /* M-Audio Fast Track Ultra */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x0763, 0x2081, /* M-Audio Fast Track Ultra */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x0763, 0x2084, /* M-Audio Venom */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_DISABLE_AUTOSUSPEND),
+	DEVICE_FLG(0x07fd, 0x000b, /* MOTU M Series 2nd hardware revision */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x08bb, 0x2702, /* LineX FM Transmitter */
+		   QUIRK_FLAG_IGNORE_CTL_ERROR),
+	DEVICE_FLG(0x0951, 0x16ad, /* Kingston HyperX */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x0a73, 0x003a, /* Mackie DLZ Creator XS */
+		   QUIRK_FLAG_ALWAYS_SET_RATE),
+	DEVICE_FLG(0x0b05, 0x1826, /* ASUS SupremeFX Hi-Fi */
+		   QUIRK_FLAG_DISABLE_AUTOSUSPEND),
+	DEVICE_FLG(0x0b05, 0x1827, /* ASUS SupremeFX Hi-Fi */
+		   QUIRK_FLAG_DISABLE_AUTOSUSPEND),
+	DEVICE_FLG(0x0b05, 0x18a6, /* ASUSTek Computer, Inc. */
+		   QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE),
+	DEVICE_FLG(0x0b0e, 0x0349, /* Jabra 550a */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x0bda, 0x498a, /* Realtek Semiconductor Corp. */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE | QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE),
+	DEVICE_FLG(0x0c45, 0x6340, /* Sonix HD USB Camera */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x0c45, 0x636b, /* Microdia JP001 USB Camera */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x0d8c, 0x000c, /* C-Media */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x0d8c, 0x0012, /* C-Media */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x0d8c, 0x0014, /* C-Media */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M | QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x0d8c, 0x0102, /* C-Media CM6206 */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x0e0b, 0xfa01, /* Feaulle Rainbow */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x0ecb, 0x205c, /* JBL Quantum610 Wireless */
+		   QUIRK_FLAG_FIXED_RATE),
+	DEVICE_FLG(0x0ecb, 0x2125, /* JBL Quantum650 Wireless */
+		   QUIRK_FLAG_FIXED_RATE),
+	DEVICE_FLG(0x0ecb, 0x2069, /* JBL Quantum810 Wireless */
+		   QUIRK_FLAG_FIXED_RATE),
+	DEVICE_FLG(0x0fd9, 0x0008, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x1038, 0x1294, /* SteelSeries Arctis Pro Wireless */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x1101, 0x0003, /* Audioengine D1 */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x12d1, 0x3a07, /* HUAWEI USB-C HEADSET */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE | QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE |
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x1224, 0x2a25, /* Jieli Technology USB PHY 2.0 */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_MIC_RES_16),
+	DEVICE_FLG(0x1395, 0x740a, /* Sennheiser DECT */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x1397, 0x0507, /* Behringer UMC202HD */
+		   QUIRK_FLAG_PLAYBACK_FIRST | QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x1397, 0x0508, /* Behringer UMC204HD */
+		   QUIRK_FLAG_PLAYBACK_FIRST | QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x1397, 0x0509, /* Behringer UMC404HD */
+		   QUIRK_FLAG_PLAYBACK_FIRST | QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x1397, 0x050c, /* Behringer Flow 8 */
+		   QUIRK_FLAG_IFB_SILENCE_ON_EMPTY),
+	DEVICE_FLG(0x1397, 0x0510, /* Behringer UV1 */
+		   QUIRK_FLAG_PLAYBACK_FIRST | QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x13e5, 0x0001, /* Serato Phono */
+		   QUIRK_FLAG_IGNORE_CTL_ERROR),
+	DEVICE_FLG(0x152a, 0x85dd, /* SMSL USB DAC */
+		   QUIRK_FLAG_DSD_RAW | QUIRK_FLAG_DISABLE_AUTOSUSPEND |
+		   QUIRK_FLAG_SKIP_IFACE_SETUP),
+	DEVICE_FLG(0x152a, 0x880a, /* NeuralDSP Quad Cortex */
+		   0), /* Doesn't have the vendor quirk which would otherwise apply */
+	DEVICE_FLG(0x1532, 0x055e, /* Razer Nommo V2 X */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x154e, 0x1002, /* Denon DCD-1500RE */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY),
+	DEVICE_FLG(0x154e, 0x1003, /* Denon DA-300USB */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY),
+	DEVICE_FLG(0x154e, 0x3005, /* Marantz HD-DAC1 */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY),
+	DEVICE_FLG(0x154e, 0x3006, /* Marantz SA-14S1 */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY),
+	DEVICE_FLG(0x154e, 0x300b, /* Marantz SA-KI RUBY / SA-12 */
+		   QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x154e, 0x500e, /* Denon DN-X1600 */
+		   QUIRK_FLAG_IGNORE_CLOCK_SOURCE),
+	DEVICE_FLG(0x1686, 0x00dd, /* Zoom R16/24 */
+		   QUIRK_FLAG_TX_LENGTH | QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x16d0, 0x0ab1, /* PureAudio APA DAC */
+		   QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x16d0, 0xeca1, /* PureAudio Lotus DAC5, DAC5 SE and DAC5 Pro */
+		   QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x17aa, 0x1046, /* Lenovo ThinkStation P620 Rear Line-in, Line-out and Microphone */
+		   QUIRK_FLAG_DISABLE_AUTOSUSPEND),
+	DEVICE_FLG(0x17aa, 0x104d, /* Lenovo ThinkStation P620 Internal Speaker + Front Headset */
+		   QUIRK_FLAG_DISABLE_AUTOSUSPEND),
+	DEVICE_FLG(0x17ef, 0x3083, /* Lenovo TBT3 dock */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x1852, 0x5062, /* Luxman D-08u */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY),
+	DEVICE_FLG(0x1852, 0x5065, /* Luxman DA-06 */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY),
+	DEVICE_FLG(0x1901, 0x0191, /* GE B850V3 CP2114 audio interface */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x19f7, 0x0003, /* RODE NT-USB */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x19f7, 0x0035, /* RODE NT-USB+ */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x1bcf, 0x2281, /* HD Webcam */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_MIC_RES_16),
+	DEVICE_FLG(0x1bcf, 0x2283, /* NexiGo N930AF FHD Webcam */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_MIC_RES_16),
+	DEVICE_FLG(0x1e0b, 0xd01e, /* Generic USB Audio Device */
+		   QUIRK_FLAG_PLAYBACK_URB_FIXUP),
+	DEVICE_FLG(0x1ff7, 0x0f81, /* SC13A Webcam */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x2040, 0x7200, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7201, /* Hauppauge HVR-950Q-MXL */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7210, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7211, /* Hauppauge HVR-950Q-MXL */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7213, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7217, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x721b, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x721e, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x721f, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7240, /* Hauppauge HVR-850 */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7260, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7270, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7280, /* Hauppauge HVR-950Q */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x2040, 0x7281, /* Hauppauge HVR-950Q-MXL */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x20b1, 0x2009, /* XMOS Ltd DIYINHK USB Audio 2.0 */
+		   QUIRK_FLAG_SKIP_IMPLICIT_FB | QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x2040, 0x8200, /* Hauppauge Woodbury */
+		   QUIRK_FLAG_SHARE_MEDIA_DEVICE | QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x21b4, 0x0081, /* AudioQuest DragonFly */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x21b4, 0x0230, /* Ayre QB-9 Twenty */
+		   QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x21b4, 0x0232, /* Ayre QX-5 Twenty */
+		   QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x2522, 0x0007, /* LH Labs Geek Out HD Audio 1V5 */
+		   QUIRK_FLAG_SET_IFACE_FIRST),
+	DEVICE_FLG(0x25aa, 0x600b, /* TAE1159 */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x262a, 0x9302, /* ddHiFi TC44C */
+		   QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x2772, 0x0502, /* Musical Fidelity M6s DAC */
+		   0), /* for avoiding QUIRK_FLAG_DSD_RAW with vendor match */
+	DEVICE_FLG(0x2912, 0x30c8, /* Audioengine D1 */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x2a70, 0x1881, /* OnePlus Technology (Shenzhen) Co., Ltd. BE02T */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE | QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE),
+	DEVICE_FLG(0x2b53, 0x0023, /* Fiero SC-01 (firmware v1.0.0 @ 48 kHz) */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x2b53, 0x0024, /* Fiero SC-01 (firmware v1.0.0 @ 96 kHz) */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x2b53, 0x0031, /* Fiero SC-01 (firmware v1.1.0) */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x2b73, 0x0047, /* AlphaTheta EUPHONIA */
+		   QUIRK_FLAG_PLAYBACK_FIRST | QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x2d95, 0x8011, /* VIVO USB-C HEADSET */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x2d95, 0x8021, /* VIVO USB-C-XE710 HEADSET */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x2d99, 0x0026, /* HECATE G2 GAMING HEADSET */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x2fc6, 0xf06b, /* MOONDROP Moonriver2 Ti */
+		   QUIRK_FLAG_CTL_MSG_DELAY),
+	DEVICE_FLG(0x2fc6, 0xf0b5, /* iBasso DC-Elite */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x2fc6, 0xf0b7, /* iBasso DC07 Pro */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	DEVICE_FLG(0x30be, 0x0101, /* Schiit Hel */
+		   QUIRK_FLAG_IGNORE_CTL_ERROR),
+	DEVICE_FLG(0x3255, 0x0000, /* Luxman D-10X */
+		   QUIRK_FLAG_ITF_USB_DSD_DAC | QUIRK_FLAG_CTL_MSG_DELAY),
+	DEVICE_FLG(0x32bb, 0x0004, /* HiBy FC4 */
+		   QUIRK_FLAG_DSD_RAW),
+	DEVICE_FLG(0x3302, 0x17c2, /* TTGK Technology USB-C Audio */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x339b, 0x3a07, /* Synaptics HONOR USB-C HEADSET */
+		   QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE),
+	DEVICE_FLG(0x3443, 0x930d, /* NexiGo N930W 60fps Webcam */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_MIC_RES_16),
+	DEVICE_FLG(0x36f9, 0xc009, /* XIBERIA K03S */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x3c20, 0x3d21, /* AB13X USB Audio */
+		   QUIRK_FLAG_FORCE_IFACE_RESET | QUIRK_FLAG_IFACE_DELAY),
+	DEVICE_FLG(0x413c, 0xa506, /* Dell AE515 sound bar */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	DEVICE_FLG(0x534d, 0x0021, /* MacroSilicon MS2100/MS2106 */
+		   QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x534d, 0x2109, /* MacroSilicon MS2109 */
+		   QUIRK_FLAG_ALIGN_TRANSFER),
+	DEVICE_FLG(0x84ef, 0x002a, /* Valeton GP-200 */
+		   QUIRK_FLAG_GENERIC_IMPLICIT_FB),
+	DEVICE_FLG(0x84ef, 0x0082, /* Hotone Audio Pulze Mini */
+		   QUIRK_FLAG_MIXER_PLAYBACK_LINEAR_VOL | QUIRK_FLAG_MIXER_CAPTURE_LINEAR_VOL),
+
+	/* Vendor and string descriptor matches */
+	VENDOR_STRING_FLG(0x1235, /* Conflict with Focusrite Novation */
+			  "MV-SILICON",
+			  0), /* Stop matching */
+
+	/* Vendor matches */
+	VENDOR_FLG(0x045e, /* MS Lifecam */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	VENDOR_FLG(0x046d, /* Logitech */
+		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
+	VENDOR_FLG(0x047f, /* Plantronics */
+		   QUIRK_FLAG_GET_SAMPLE_RATE | QUIRK_FLAG_CTL_MSG_DELAY),
+	VENDOR_FLG(0x0644, /* TEAC Corp. */
+		   QUIRK_FLAG_CTL_MSG_DELAY | QUIRK_FLAG_IFACE_DELAY),
+	VENDOR_FLG(0x07fd, /* MOTU */
+		   QUIRK_FLAG_VALIDATE_RATES),
+	DEVICE_FLG(0x1235, 0x8006, 0), /* Focusrite Scarlett 2i2 1st Gen */
+	DEVICE_FLG(0x1235, 0x800a, 0), /* Focusrite Scarlett 2i4 1st Gen */
+	DEVICE_FLG(0x1235, 0x800c, 0), /* Focusrite Scarlett 18i20 1st Gen */
+	DEVICE_FLG(0x1235, 0x8016, 0), /* Focusrite Scarlett 2i2 1st Gen */
+	DEVICE_FLG(0x1235, 0x801c, 0), /* Focusrite Scarlett Solo 1st Gen */
+	VENDOR_FLG(0x1235, /* Focusrite Novation */
+		   QUIRK_FLAG_SKIP_CLOCK_SELECTOR |
+		   QUIRK_FLAG_SKIP_IFACE_SETUP),
+	VENDOR_FLG(0x1511, /* AURALiC */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x152a, /* Thesycon devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x18d1, /* iBasso devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x1de7, /* Phoenix Audio */
+		   QUIRK_FLAG_GET_SAMPLE_RATE),
+	VENDOR_FLG(0x20b1, /* XMOS based devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x21ed, /* Accuphase Laboratory */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x22d9, /* Oppo */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x23ba, /* Playback Design */
+		   QUIRK_FLAG_CTL_MSG_DELAY | QUIRK_FLAG_IFACE_DELAY |
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x25ce, /* Mytek devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x2622, /* IAG Limited devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x2708, /* Audient devices */
+		   QUIRK_FLAG_IGNORE_CTL_ERROR),
+	VENDOR_FLG(0x2772, /* Musical Fidelity devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x278b, /* Rotel? */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x292b, /* Gustard/Ess based devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x2972, /* FiiO devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x2ab6, /* T+A devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x2afd, /* McIntosh Laboratory, Inc. */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x2d87, /* Cayin device */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x2fc6, /* Comture-inc devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x3336, /* HEM devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x3353, /* Khadas devices */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x35f4, /* MSB Technology */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0x3842, /* EVGA */
+		   QUIRK_FLAG_DSD_RAW),
+	VENDOR_FLG(0xc502, /* HiBy devices */
+		   QUIRK_FLAG_DSD_RAW),
+
+	{} /* terminator */
+};
+
+#define QUIRK_STRING_ENTRY(x) \
+	[QUIRK_TYPE_ ## x] = __stringify(x)
+
+static const char *const snd_usb_audio_quirk_flag_names[] = {
+	QUIRK_STRING_ENTRY(GET_SAMPLE_RATE),
+	QUIRK_STRING_ENTRY(SHARE_MEDIA_DEVICE),
+	QUIRK_STRING_ENTRY(ALIGN_TRANSFER),
+	QUIRK_STRING_ENTRY(TX_LENGTH),
+	QUIRK_STRING_ENTRY(PLAYBACK_FIRST),
+	QUIRK_STRING_ENTRY(SKIP_CLOCK_SELECTOR),
+	QUIRK_STRING_ENTRY(IGNORE_CLOCK_SOURCE),
+	QUIRK_STRING_ENTRY(ITF_USB_DSD_DAC),
+	QUIRK_STRING_ENTRY(CTL_MSG_DELAY),
+	QUIRK_STRING_ENTRY(CTL_MSG_DELAY_1M),
+	QUIRK_STRING_ENTRY(CTL_MSG_DELAY_5M),
+	QUIRK_STRING_ENTRY(IFACE_DELAY),
+	QUIRK_STRING_ENTRY(VALIDATE_RATES),
+	QUIRK_STRING_ENTRY(DISABLE_AUTOSUSPEND),
+	QUIRK_STRING_ENTRY(IGNORE_CTL_ERROR),
+	QUIRK_STRING_ENTRY(DSD_RAW),
+	QUIRK_STRING_ENTRY(SET_IFACE_FIRST),
+	QUIRK_STRING_ENTRY(GENERIC_IMPLICIT_FB),
+	QUIRK_STRING_ENTRY(SKIP_IMPLICIT_FB),
+	QUIRK_STRING_ENTRY(IFACE_SKIP_CLOSE),
+	QUIRK_STRING_ENTRY(FORCE_IFACE_RESET),
+	QUIRK_STRING_ENTRY(FIXED_RATE),
+	QUIRK_STRING_ENTRY(MIC_RES_16),
+	QUIRK_STRING_ENTRY(MIC_RES_384),
+	QUIRK_STRING_ENTRY(MIXER_PLAYBACK_MIN_MUTE),
+	QUIRK_STRING_ENTRY(MIXER_CAPTURE_MIN_MUTE),
+	QUIRK_STRING_ENTRY(SKIP_IFACE_SETUP),
+	QUIRK_STRING_ENTRY(MIXER_PLAYBACK_LINEAR_VOL),
+	QUIRK_STRING_ENTRY(MIXER_CAPTURE_LINEAR_VOL),
+	QUIRK_STRING_ENTRY(IFB_SILENCE_ON_EMPTY),
+	QUIRK_STRING_ENTRY(MIXER_GET_CUR_OK),
+	QUIRK_STRING_ENTRY(PLAYBACK_URB_FIXUP),
+	QUIRK_STRING_ENTRY(ALWAYS_SET_RATE),
+	NULL
+};
+
+static u64 snd_usb_quirk_flags_from_name(const char *name)
+{
+	int i;
+
+	if (!name || !*name)
+		return 0;
+
+	for (i = 0; snd_usb_audio_quirk_flag_names[i]; i++) {
+		if (strcasecmp(name, snd_usb_audio_quirk_flag_names[i]) == 0)
+			return BIT_U64(i);
+	}
+
+	return 0;
+}
+
+void snd_usb_apply_flag_dbg(const char *reason,
+			    struct snd_usb_audio *chip,
+			    unsigned long flag)
+{
+	unsigned long bit;
+
+	for_each_set_bit(bit, &flag, BYTES_TO_BITS(sizeof(flag))) {
+		const char *name = snd_usb_audio_quirk_flag_names[bit];
+
+		if (name)
+			usb_audio_dbg(chip,
+				      "From %s apply quirk flag %s for device %04x:%04x\n",
+				      reason, name, USB_ID_VENDOR(chip->usb_id),
+				      USB_ID_PRODUCT(chip->usb_id));
+		else
+			usb_audio_warn(chip,
+				       "From %s apply unknown quirk flag 0x%lx for device %04x:%04x\n",
+				       reason, bit, USB_ID_VENDOR(chip->usb_id),
+				       USB_ID_PRODUCT(chip->usb_id));
+	}
+}
+
+void snd_usb_init_quirk_flags_table(struct snd_usb_audio *chip)
+{
+	const struct usb_audio_quirk_flags_table *p;
+
+	for (p = quirk_flags_table; p->id; p++) {
+		if (chip->usb_id == p->id ||
+		    (!USB_ID_PRODUCT(p->id) &&
+		     USB_ID_VENDOR(chip->usb_id) == USB_ID_VENDOR(p->id))) {
+			/* Handle DEVICE_STRING_FLG/VENDOR_STRING_FLG. */
+			if (p->usb_string_match && p->usb_string_match->manufacturer &&
+			    strcmp(p->usb_string_match->manufacturer,
+				   chip->dev->manufacturer ? chip->dev->manufacturer : ""))
+				continue;
+			if (p->usb_string_match && p->usb_string_match->product &&
+			    strcmp(p->usb_string_match->product,
+				   chip->dev->product ? chip->dev->product : ""))
+				continue;
+
+			snd_usb_apply_flag_dbg("builtin table", chip, p->flags);
+			chip->quirk_flags |= p->flags;
+			return;
+		}
+	}
+}
+
+void snd_usb_init_quirk_flags_parse_string(struct snd_usb_audio *chip,
+					   const char *str)
+{
+	u16 chip_vid = USB_ID_VENDOR(chip->usb_id);
+	u16 chip_pid = USB_ID_PRODUCT(chip->usb_id);
+	u64 mask_flags, unmask_flags, bit;
+	char *p, *field, *flag;
+	bool is_unmask;
+	u16 vid, pid;
+
+	char *val __free(kfree) = kstrdup(str, GFP_KERNEL);
+
+	if (!val)
+		return;
+
+	for (p = val; p && *p;) {
+		/* Each entry consists of VID:PID:flags */
+		field = strsep(&p, ":");
+		if (!field)
+			break;
+
+		if (strcmp(field, "*") == 0)
+			vid = 0;
+		else if (kstrtou16(field, 16, &vid))
+			break;
+
+		field = strsep(&p, ":");
+		if (!field)
+			break;
+
+		if (strcmp(field, "*") == 0)
+			pid = 0;
+		else if (kstrtou16(field, 16, &pid))
+			break;
+
+		field = strsep(&p, ";");
+		if (!field || !*field)
+			break;
+
+		if ((vid != 0 && vid != chip_vid) ||
+		    (pid != 0 && pid != chip_pid))
+			continue;
+
+		/* Collect the flags */
+		mask_flags = 0;
+		unmask_flags = 0;
+		while (field && *field) {
+			flag = strsep(&field, "|");
+
+			if (!flag)
+				break;
+
+			if (*flag == '!') {
+				is_unmask = true;
+				flag++;
+			} else {
+				is_unmask = false;
+			}
+
+			if (!kstrtou64(flag, 16, &bit)) {
+				if (is_unmask)
+					unmask_flags |= bit;
+				else
+					mask_flags |= bit;
+
+				break;
+			}
+
+			bit = snd_usb_quirk_flags_from_name(flag);
+
+			if (bit) {
+				if (is_unmask)
+					unmask_flags |= bit;
+				else
+					mask_flags |= bit;
+			} else {
+				pr_warn("snd_usb_audio: unknown flag %s while parsing param quirk_flags\n",
+					flag);
+			}
+		}
+
+		chip->quirk_flags &= ~unmask_flags;
+		chip->quirk_flags |= mask_flags;
+		snd_usb_apply_flag_dbg("module param", chip,
+				       chip->quirk_flags);
+	}
+}
diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
new file mode 100644
index 000000000..0a723c266
--- /dev/null
+++ b/sound/usb/quirks.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_QUIRKS_H
+#define __USBAUDIO_QUIRKS_H
+
+struct audioformat;
+struct snd_usb_endpoint;
+struct snd_usb_substream;
+
+int snd_usb_create_quirk(struct snd_usb_audio *chip,
+			 struct usb_interface *iface,
+			 struct usb_driver *driver,
+			 const struct snd_usb_audio_quirk *quirk);
+
+int snd_usb_apply_interface_quirk(struct snd_usb_audio *chip,
+				  int iface,
+				  int altno);
+
+int snd_usb_apply_boot_quirk(struct usb_device *dev,
+			     struct usb_interface *intf,
+			     const struct snd_usb_audio_quirk *quirk,
+			     unsigned int usb_id);
+
+int snd_usb_apply_boot_quirk_once(struct usb_device *dev,
+				  struct usb_interface *intf,
+				  const struct snd_usb_audio_quirk *quirk,
+				  unsigned int usb_id);
+
+void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
+			      const struct audioformat *fmt);
+
+int snd_usb_is_big_endian_format(struct snd_usb_audio *chip,
+				 const struct audioformat *fp);
+
+void snd_usb_endpoint_start_quirk(struct snd_usb_endpoint *ep);
+
+void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
+			   __u8 request, __u8 requesttype, __u16 value,
+			   __u16 index, void *data, __u16 size);
+
+int snd_usb_select_mode_quirk(struct snd_usb_audio *chip,
+			      const struct audioformat *fmt);
+
+u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
+					struct audioformat *fp,
+					unsigned int sample_bytes);
+
+void snd_usb_audioformat_attributes_quirk(struct snd_usb_audio *chip,
+					  struct audioformat *fp,
+					  int stream);
+
+void snd_usb_apply_flag_dbg(const char *reason,
+			    struct snd_usb_audio *chip,
+			    unsigned long flag);
+
+void snd_usb_init_quirk_flags_table(struct snd_usb_audio *chip);
+void snd_usb_init_quirk_flags_parse_string(struct snd_usb_audio *chip,
+					   const char *str);
+
+#endif /* __USBAUDIO_QUIRKS_H */
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
new file mode 100644
index 000000000..b2c5c8198
--- /dev/null
+++ b/sound/usb/stream.c
@@ -0,0 +1,1291 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/control.h>
+#include <sound/tlv.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "proc.h"
+#include "quirks.h"
+#include "endpoint.h"
+#include "pcm.h"
+#include "helper.h"
+#include "format.h"
+#include "clock.h"
+#include "stream.h"
+#include "power.h"
+#include "media.h"
+
+static void audioformat_free(struct audioformat *fp)
+{
+	list_del(&fp->list); /* unlink for avoiding double-free */
+	kfree(fp->rate_table);
+	kfree(fp->chmap);
+	kfree(fp);
+}
+
+/*
+ * free a substream
+ */
+static void free_substream(struct snd_usb_substream *subs)
+{
+	struct audioformat *fp, *n;
+
+	if (!subs->num_formats)
+		return; /* not initialized */
+	list_for_each_entry_safe(fp, n, &subs->fmt_list, list)
+		audioformat_free(fp);
+	kfree(subs->str_pd);
+	snd_media_stream_delete(subs);
+}
+
+
+/*
+ * free a usb stream instance
+ */
+static void snd_usb_audio_stream_free(struct snd_usb_stream *stream)
+{
+	free_substream(&stream->substream[0]);
+	free_substream(&stream->substream[1]);
+	list_del(&stream->list);
+	kfree(stream);
+}
+
+static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
+{
+	struct snd_usb_stream *stream = pcm->private_data;
+	if (stream) {
+		stream->pcm = NULL;
+		snd_usb_audio_stream_free(stream);
+	}
+}
+
+/*
+ * initialize the substream instance.
+ */
+
+static void snd_usb_init_substream(struct snd_usb_stream *as,
+				   int stream,
+				   struct audioformat *fp,
+				   struct snd_usb_power_domain **pdptr)
+{
+	struct snd_usb_substream *subs = &as->substream[stream];
+
+	INIT_LIST_HEAD(&subs->fmt_list);
+	spin_lock_init(&subs->lock);
+
+	subs->stream = as;
+	subs->direction = stream;
+	subs->dev = as->chip->dev;
+	subs->txfr_quirk = !!(as->chip->quirk_flags & QUIRK_FLAG_ALIGN_TRANSFER);
+	subs->tx_length_quirk = !!(as->chip->quirk_flags & QUIRK_FLAG_TX_LENGTH);
+	subs->speed = snd_usb_get_speed(subs->dev);
+	subs->pkt_offset_adj = 0;
+	subs->stream_offset_adj = 0;
+
+	snd_usb_set_pcm_ops(as->pcm, stream);
+
+	list_add_tail(&fp->list, &subs->fmt_list);
+	subs->formats |= fp->formats;
+	subs->num_formats++;
+	subs->fmt_type = fp->fmt_type;
+	subs->ep_num = fp->endpoint;
+	if (fp->channels > subs->channels_max)
+		subs->channels_max = fp->channels;
+
+	if (pdptr && *pdptr) {
+		subs->str_pd = *pdptr;
+		*pdptr = NULL; /* assigned */
+		/* Initialize Power Domain to idle status D1 */
+		snd_usb_power_domain_set(subs->stream->chip, subs->str_pd,
+					 UAC3_PD_STATE_D1);
+	}
+
+	snd_usb_preallocate_buffer(subs);
+}
+
+/* kctl callbacks for usb-audio channel maps */
+static int usb_chmap_ctl_info(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_info *uinfo)
+{
+	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_substream *subs = info->private_data;
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = subs->channels_max;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = SNDRV_CHMAP_LAST;
+	return 0;
+}
+
+/* check whether a duplicated entry exists in the audiofmt list */
+static bool have_dup_chmap(struct snd_usb_substream *subs,
+			   struct audioformat *fp)
+{
+	struct audioformat *prev = fp;
+
+	list_for_each_entry_continue_reverse(prev, &subs->fmt_list, list) {
+		if (prev->chmap &&
+		    !memcmp(prev->chmap, fp->chmap, sizeof(*fp->chmap)))
+			return true;
+	}
+	return false;
+}
+
+static int usb_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
+			     unsigned int size, unsigned int __user *tlv)
+{
+	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_substream *subs = info->private_data;
+	struct audioformat *fp;
+	unsigned int __user *dst;
+	int count = 0;
+
+	if (size < 8)
+		return -ENOMEM;
+	if (put_user(SNDRV_CTL_TLVT_CONTAINER, tlv))
+		return -EFAULT;
+	size -= 8;
+	dst = tlv + 2;
+	list_for_each_entry(fp, &subs->fmt_list, list) {
+		int i, ch_bytes;
+
+		if (!fp->chmap)
+			continue;
+		if (have_dup_chmap(subs, fp))
+			continue;
+		/* copy the entry */
+		ch_bytes = fp->chmap->channels * 4;
+		if (size < 8 + ch_bytes)
+			return -ENOMEM;
+		if (put_user(SNDRV_CTL_TLVT_CHMAP_FIXED, dst) ||
+		    put_user(ch_bytes, dst + 1))
+			return -EFAULT;
+		dst += 2;
+		for (i = 0; i < fp->chmap->channels; i++, dst++) {
+			if (put_user(fp->chmap->map[i], dst))
+				return -EFAULT;
+		}
+
+		count += 8 + ch_bytes;
+		size -= 8 + ch_bytes;
+	}
+	if (put_user(count, tlv + 1))
+		return -EFAULT;
+	return 0;
+}
+
+static int usb_chmap_ctl_get(struct snd_kcontrol *kcontrol,
+			     struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
+	struct snd_usb_substream *subs = info->private_data;
+	struct snd_pcm_chmap_elem *chmap = NULL;
+	int i = 0;
+
+	if (subs->cur_audiofmt)
+		chmap = subs->cur_audiofmt->chmap;
+	if (chmap) {
+		for (i = 0; i < chmap->channels; i++)
+			ucontrol->value.integer.value[i] = chmap->map[i];
+	}
+	for (; i < subs->channels_max; i++)
+		ucontrol->value.integer.value[i] = 0;
+	return 0;
+}
+
+/* create a chmap kctl assigned to the given USB substream */
+static int add_chmap(struct snd_pcm *pcm, int stream,
+		     struct snd_usb_substream *subs)
+{
+	struct audioformat *fp;
+	struct snd_pcm_chmap *chmap;
+	struct snd_kcontrol *kctl;
+	int err;
+
+	list_for_each_entry(fp, &subs->fmt_list, list)
+		if (fp->chmap)
+			goto ok;
+	/* no chmap is found */
+	return 0;
+
+ ok:
+	err = snd_pcm_add_chmap_ctls(pcm, stream, NULL, 0, 0, &chmap);
+	if (err < 0)
+		return err;
+
+	/* override handlers */
+	chmap->private_data = subs;
+	kctl = chmap->kctl;
+	kctl->info = usb_chmap_ctl_info;
+	kctl->get = usb_chmap_ctl_get;
+	kctl->tlv.c = usb_chmap_ctl_tlv;
+
+	return 0;
+}
+
+/* convert from USB ChannelConfig bits to ALSA chmap element */
+static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
+						int protocol)
+{
+	static const unsigned int uac1_maps[] = {
+		SNDRV_CHMAP_FL,		/* left front */
+		SNDRV_CHMAP_FR,		/* right front */
+		SNDRV_CHMAP_FC,		/* center front */
+		SNDRV_CHMAP_LFE,	/* LFE */
+		SNDRV_CHMAP_RL,		/* left surround */
+		SNDRV_CHMAP_RR,		/* right surround */
+		SNDRV_CHMAP_FLC,	/* left of center */
+		SNDRV_CHMAP_FRC,	/* right of center */
+		SNDRV_CHMAP_RC,		/* surround */
+		SNDRV_CHMAP_SL,		/* side left */
+		SNDRV_CHMAP_SR,		/* side right */
+		SNDRV_CHMAP_TC,		/* top */
+		0 /* terminator */
+	};
+	static const unsigned int uac2_maps[] = {
+		SNDRV_CHMAP_FL,		/* front left */
+		SNDRV_CHMAP_FR,		/* front right */
+		SNDRV_CHMAP_FC,		/* front center */
+		SNDRV_CHMAP_LFE,	/* LFE */
+		SNDRV_CHMAP_RL,		/* back left */
+		SNDRV_CHMAP_RR,		/* back right */
+		SNDRV_CHMAP_FLC,	/* front left of center */
+		SNDRV_CHMAP_FRC,	/* front right of center */
+		SNDRV_CHMAP_RC,		/* back center */
+		SNDRV_CHMAP_SL,		/* side left */
+		SNDRV_CHMAP_SR,		/* side right */
+		SNDRV_CHMAP_TC,		/* top center */
+		SNDRV_CHMAP_TFL,	/* top front left */
+		SNDRV_CHMAP_TFC,	/* top front center */
+		SNDRV_CHMAP_TFR,	/* top front right */
+		SNDRV_CHMAP_TRL,	/* top back left */
+		SNDRV_CHMAP_TRC,	/* top back center */
+		SNDRV_CHMAP_TRR,	/* top back right */
+		SNDRV_CHMAP_TFLC,	/* top front left of center */
+		SNDRV_CHMAP_TFRC,	/* top front right of center */
+		SNDRV_CHMAP_LLFE,	/* left LFE */
+		SNDRV_CHMAP_RLFE,	/* right LFE */
+		SNDRV_CHMAP_TSL,	/* top side left */
+		SNDRV_CHMAP_TSR,	/* top side right */
+		SNDRV_CHMAP_BC,		/* bottom center */
+		SNDRV_CHMAP_RLC,	/* back left of center */
+		SNDRV_CHMAP_RRC,	/* back right of center */
+		0 /* terminator */
+	};
+	struct snd_pcm_chmap_elem *chmap;
+	const unsigned int *maps;
+	int c;
+
+	if (channels > ARRAY_SIZE(chmap->map))
+		return NULL;
+
+	chmap = kzalloc_obj(*chmap);
+	if (!chmap)
+		return NULL;
+
+	maps = protocol == UAC_VERSION_2 ? uac2_maps : uac1_maps;
+	chmap->channels = channels;
+	c = 0;
+
+	if (bits) {
+		for (; bits && *maps; maps++, bits >>= 1) {
+			if (bits & 1)
+				chmap->map[c++] = *maps;
+			if (c == chmap->channels)
+				break;
+		}
+	} else {
+		/* If we're missing wChannelConfig, then guess something
+		    to make sure the channel map is not skipped entirely */
+		if (channels == 1)
+			chmap->map[c++] = SNDRV_CHMAP_MONO;
+		else
+			for (; c < channels && *maps; maps++)
+				chmap->map[c++] = *maps;
+	}
+
+	for (; c < channels; c++)
+		chmap->map[c] = SNDRV_CHMAP_UNKNOWN;
+
+	return chmap;
+}
+
+/* UAC3 device stores channels information in Cluster Descriptors */
+static struct
+snd_pcm_chmap_elem *convert_chmap_v3(struct uac3_cluster_header_descriptor
+								*cluster)
+{
+	unsigned int channels = cluster->bNrChannels;
+	struct snd_pcm_chmap_elem *chmap;
+	void *p = cluster;
+	int len, c;
+
+	if (channels > ARRAY_SIZE(chmap->map))
+		return NULL;
+
+	chmap = kzalloc_obj(*chmap);
+	if (!chmap)
+		return NULL;
+
+	len = le16_to_cpu(cluster->wLength);
+	c = 0;
+	p += sizeof(*cluster);
+	len -= sizeof(*cluster);
+
+	while (len > 0 && (c < channels)) {
+		struct uac3_cluster_segment_descriptor *cs_desc = p;
+		u16 cs_len;
+		u8 cs_type;
+
+		if (len < sizeof(*cs_desc))
+			break;
+		cs_len = le16_to_cpu(cs_desc->wLength);
+		if (cs_len < sizeof(*cs_desc))
+			break;
+		if (len < cs_len)
+			break;
+		cs_type = cs_desc->bSegmentType;
+
+		if (cs_type == UAC3_CHANNEL_INFORMATION) {
+			struct uac3_cluster_information_segment_descriptor *is = p;
+			unsigned char map;
+
+			if (cs_len < sizeof(*is))
+				break;
+
+			/*
+			 * TODO: this conversion is not complete, update it
+			 * after adding UAC3 values to asound.h
+			 * NOTE: not all UAC3 channel relationship have a
+			 * direct ALSA chmap equivalent.
+			 */
+			switch (is->bChRelationship) {
+			case UAC3_CH_MONO:
+				map = SNDRV_CHMAP_MONO;
+				break;
+			case UAC3_CH_LEFT:
+			case UAC3_CH_FRONT_LEFT:
+			case UAC3_CH_HEADPHONE_LEFT:
+				map = SNDRV_CHMAP_FL;
+				break;
+			case UAC3_CH_RIGHT:
+			case UAC3_CH_FRONT_RIGHT:
+			case UAC3_CH_HEADPHONE_RIGHT:
+				map = SNDRV_CHMAP_FR;
+				break;
+			case UAC3_CH_FRONT_CENTER:
+				map = SNDRV_CHMAP_FC;
+				break;
+			case UAC3_CH_FRONT_LEFT_OF_CENTER:
+				map = SNDRV_CHMAP_FLC;
+				break;
+			case UAC3_CH_FRONT_RIGHT_OF_CENTER:
+				map = SNDRV_CHMAP_FRC;
+				break;
+			case UAC3_CH_FRONT_WIDE_LEFT:
+				map = SNDRV_CHMAP_FLW;
+				break;
+			case UAC3_CH_FRONT_WIDE_RIGHT:
+				map = SNDRV_CHMAP_FRW;
+				break;
+			case UAC3_CH_SIDE_LEFT:
+				map = SNDRV_CHMAP_SL;
+				break;
+			case UAC3_CH_SIDE_RIGHT:
+				map = SNDRV_CHMAP_SR;
+				break;
+			case UAC3_CH_BACK_LEFT:
+				map = SNDRV_CHMAP_RL;
+				break;
+			case UAC3_CH_BACK_RIGHT:
+				map = SNDRV_CHMAP_RR;
+				break;
+			case UAC3_CH_BACK_CENTER:
+				map = SNDRV_CHMAP_RC;
+				break;
+			case UAC3_CH_BACK_LEFT_OF_CENTER:
+				map = SNDRV_CHMAP_RLC;
+				break;
+			case UAC3_CH_BACK_RIGHT_OF_CENTER:
+				map = SNDRV_CHMAP_RRC;
+				break;
+			case UAC3_CH_TOP_CENTER:
+				map = SNDRV_CHMAP_TC;
+				break;
+			case UAC3_CH_TOP_FRONT_LEFT:
+				map = SNDRV_CHMAP_TFL;
+				break;
+			case UAC3_CH_TOP_FRONT_RIGHT:
+				map = SNDRV_CHMAP_TFR;
+				break;
+			case UAC3_CH_TOP_FRONT_CENTER:
+				map = SNDRV_CHMAP_TFC;
+				break;
+			case UAC3_CH_TOP_FRONT_LOC:
+				map = SNDRV_CHMAP_TFLC;
+				break;
+			case UAC3_CH_TOP_FRONT_ROC:
+				map = SNDRV_CHMAP_TFRC;
+				break;
+			case UAC3_CH_TOP_SIDE_LEFT:
+				map = SNDRV_CHMAP_TSL;
+				break;
+			case UAC3_CH_TOP_SIDE_RIGHT:
+				map = SNDRV_CHMAP_TSR;
+				break;
+			case UAC3_CH_TOP_BACK_LEFT:
+				map = SNDRV_CHMAP_TRL;
+				break;
+			case UAC3_CH_TOP_BACK_RIGHT:
+				map = SNDRV_CHMAP_TRR;
+				break;
+			case UAC3_CH_TOP_BACK_CENTER:
+				map = SNDRV_CHMAP_TRC;
+				break;
+			case UAC3_CH_BOTTOM_CENTER:
+				map = SNDRV_CHMAP_BC;
+				break;
+			case UAC3_CH_LOW_FREQUENCY_EFFECTS:
+				map = SNDRV_CHMAP_LFE;
+				break;
+			case UAC3_CH_LFE_LEFT:
+				map = SNDRV_CHMAP_LLFE;
+				break;
+			case UAC3_CH_LFE_RIGHT:
+				map = SNDRV_CHMAP_RLFE;
+				break;
+			case UAC3_CH_RELATIONSHIP_UNDEFINED:
+			default:
+				map = SNDRV_CHMAP_UNKNOWN;
+				break;
+			}
+			chmap->map[c++] = map;
+		}
+		p += cs_len;
+		len -= cs_len;
+	}
+
+	if (channels < c)
+		pr_err("%s: channel number mismatch\n", __func__);
+
+	chmap->channels = channels;
+
+	for (; c < channels; c++)
+		chmap->map[c] = SNDRV_CHMAP_UNKNOWN;
+
+	return chmap;
+}
+
+/*
+ * add this endpoint to the chip instance.
+ * if a stream with the same endpoint already exists, append to it.
+ * if not, create a new pcm stream. note, fp is added to the substream
+ * fmt_list and will be freed on the chip instance release. do not free
+ * fp or do remove it from the substream fmt_list to avoid double-free.
+ *
+ * pdptr is optional and can be NULL.  When it's non-NULL and the PD gets
+ * assigned to the stream, *pdptr is cleared to NULL upon return.
+ */
+int snd_usb_add_audio_stream(struct snd_usb_audio *chip,
+			     int stream,
+			     struct audioformat *fp,
+			     struct snd_usb_power_domain **pdptr)
+
+{
+	struct snd_usb_stream *as;
+	struct snd_usb_substream *subs;
+	struct snd_pcm *pcm;
+	int err;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		if (as->fmt_type != fp->fmt_type)
+			continue;
+		subs = &as->substream[stream];
+		if (subs->ep_num == fp->endpoint) {
+			list_add_tail(&fp->list, &subs->fmt_list);
+			subs->num_formats++;
+			subs->formats |= fp->formats;
+			return 0;
+		}
+	}
+
+	if (chip->card->registered)
+		chip->need_delayed_register = true;
+
+	/* look for an empty stream */
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		if (as->fmt_type != fp->fmt_type)
+			continue;
+		subs = &as->substream[stream];
+		if (subs->ep_num)
+			continue;
+		err = snd_pcm_new_stream(as->pcm, stream, 1);
+		if (err < 0)
+			return err;
+		snd_usb_init_substream(as, stream, fp, pdptr);
+		return add_chmap(as->pcm, stream, subs);
+	}
+
+	/* create a new pcm */
+	as = kzalloc_obj(*as);
+	if (!as)
+		return -ENOMEM;
+	as->pcm_index = chip->pcm_devs;
+	as->chip = chip;
+	as->fmt_type = fp->fmt_type;
+	err = snd_pcm_new(chip->card, "USB Audio", chip->pcm_devs,
+			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 1 : 0,
+			  stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1,
+			  &pcm);
+	if (err < 0) {
+		kfree(as);
+		return err;
+	}
+	as->pcm = pcm;
+	pcm->private_data = as;
+	pcm->private_free = snd_usb_audio_pcm_free;
+	pcm->info_flags = 0;
+	if (chip->pcm_devs > 0)
+		scnprintf(pcm->name, sizeof(pcm->name), "USB Audio #%d",
+			  chip->pcm_devs);
+	else
+		strscpy(pcm->name, "USB Audio");
+
+	snd_usb_init_substream(as, stream, fp, pdptr);
+
+	/*
+	 * Keep using head insertion for M-Audio Audiophile USB (tm) which has a
+	 * fix to swap capture stream order in conf/cards/USB-audio.conf
+	 */
+	if (chip->usb_id == USB_ID(0x0763, 0x2003))
+		list_add(&as->list, &chip->pcm_list);
+	else
+		list_add_tail(&as->list, &chip->pcm_list);
+
+	chip->pcm_devs++;
+
+	snd_usb_proc_pcm_format_add(as);
+
+	return add_chmap(pcm, stream, &as->substream[stream]);
+}
+
+static int parse_uac_endpoint_attributes(struct snd_usb_audio *chip,
+					 struct usb_host_interface *alts,
+					 int protocol, int iface_no)
+{
+	/* parsed with a v1 header here. that's ok as we only look at the
+	 * header first which is the same for both versions */
+	struct uac_iso_endpoint_descriptor *csep;
+	struct usb_interface_descriptor *altsd = get_iface_desc(alts);
+	int attributes = 0;
+
+	csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);
+
+	/* Creamware Noah has this descriptor after the 2nd endpoint */
+	if (!csep && altsd->bNumEndpoints >= 2)
+		csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
+
+	/*
+	 * If we can't locate the USB_DT_CS_ENDPOINT descriptor in the extra
+	 * bytes after the first endpoint, go search the entire interface.
+	 * Some devices have it directly *before* the standard endpoint.
+	 */
+	if (!csep)
+		csep = snd_usb_find_desc(alts->extra, alts->extralen, NULL, USB_DT_CS_ENDPOINT);
+
+	if (!csep || csep->bLength < 7 ||
+	    csep->bDescriptorSubtype != UAC_EP_GENERAL)
+		goto error;
+
+	if (protocol == UAC_VERSION_1) {
+		attributes = csep->bmAttributes;
+	} else if (protocol == UAC_VERSION_2) {
+		struct uac2_iso_endpoint_descriptor *csep2 =
+			(struct uac2_iso_endpoint_descriptor *) csep;
+
+		if (csep2->bLength < sizeof(*csep2))
+			goto error;
+		attributes = csep->bmAttributes & UAC_EP_CS_ATTR_FILL_MAX;
+
+		/* emulate the endpoint attributes of a v1 device */
+		if (csep2->bmControls & UAC2_CONTROL_PITCH)
+			attributes |= UAC_EP_CS_ATTR_PITCH_CONTROL;
+	} else { /* UAC_VERSION_3 */
+		struct uac3_iso_endpoint_descriptor *csep3 =
+			(struct uac3_iso_endpoint_descriptor *) csep;
+
+		if (csep3->bLength < sizeof(*csep3))
+			goto error;
+		/* emulate the endpoint attributes of a v1 device */
+		if (le32_to_cpu(csep3->bmControls) & UAC2_CONTROL_PITCH)
+			attributes |= UAC_EP_CS_ATTR_PITCH_CONTROL;
+	}
+
+	return attributes;
+
+ error:
+	usb_audio_warn(chip,
+		       "%u:%d : no or invalid class specific endpoint descriptor\n",
+		       iface_no, altsd->bAlternateSetting);
+	return 0;
+}
+
+/* find an input terminal descriptor (either UAC1 or UAC2) with the given
+ * terminal id
+ */
+static void *
+snd_usb_find_input_terminal_descriptor(struct usb_host_interface *ctrl_iface,
+				       int terminal_id, int protocol)
+{
+	struct uac2_input_terminal_descriptor *term = NULL;
+
+	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
+					       ctrl_iface->extralen,
+					       term, UAC_INPUT_TERMINAL))) {
+		if (!snd_usb_validate_audio_desc(term, protocol))
+			continue;
+		if (term->bTerminalID == terminal_id)
+			return term;
+	}
+
+	return NULL;
+}
+
+static void *
+snd_usb_find_output_terminal_descriptor(struct usb_host_interface *ctrl_iface,
+					int terminal_id, int protocol)
+{
+	/* OK to use with both UAC2 and UAC3 */
+	struct uac2_output_terminal_descriptor *term = NULL;
+
+	while ((term = snd_usb_find_csint_desc(ctrl_iface->extra,
+					       ctrl_iface->extralen,
+					       term, UAC_OUTPUT_TERMINAL))) {
+		if (!snd_usb_validate_audio_desc(term, protocol))
+			continue;
+		if (term->bTerminalID == terminal_id)
+			return term;
+	}
+
+	return NULL;
+}
+
+static struct audioformat *
+audio_format_alloc_init(struct snd_usb_audio *chip,
+		       struct usb_host_interface *alts,
+		       int protocol, int iface_no, int altset_idx,
+		       int altno, int num_channels, int clock)
+{
+	struct usb_host_endpoint *ep = &alts->endpoint[0];
+	struct audioformat *fp;
+
+	fp = kzalloc_obj(*fp);
+	if (!fp)
+		return NULL;
+
+	fp->iface = iface_no;
+	fp->altsetting = altno;
+	fp->altset_idx = altset_idx;
+	fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
+	fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
+	fp->datainterval = snd_usb_parse_datainterval(chip, alts);
+	fp->protocol = protocol;
+	fp->maxpacksize = usb_endpoint_max_periodic_payload(chip->dev, ep);
+	fp->channels = num_channels;
+	fp->clock = clock;
+	INIT_LIST_HEAD(&fp->list);
+
+	return fp;
+}
+
+static struct audioformat *
+snd_usb_get_audioformat_uac12(struct snd_usb_audio *chip,
+			      struct usb_host_interface *alts,
+			      int protocol, int iface_no, int altset_idx,
+			      int altno, int stream, int bm_quirk)
+{
+	struct usb_device *dev = chip->dev;
+	struct uac_format_type_i_continuous_descriptor *fmt;
+	unsigned int num_channels = 0, chconfig = 0;
+	struct usb_host_interface *ctrl_intf;
+	struct audioformat *fp;
+	int clock = 0;
+	u64 format;
+
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, iface_no);
+
+	/* get audio formats */
+	if (protocol == UAC_VERSION_1) {
+		struct uac1_as_header_descriptor *as =
+			snd_usb_find_csint_desc(alts->extra, alts->extralen,
+						NULL, UAC_AS_GENERAL);
+		struct uac_input_terminal_descriptor *iterm;
+
+		if (!as) {
+			dev_err(&dev->dev,
+				"%u:%d : UAC_AS_GENERAL descriptor not found\n",
+				iface_no, altno);
+			return NULL;
+		}
+
+		if (as->bLength < sizeof(*as)) {
+			dev_err(&dev->dev,
+				"%u:%d : invalid UAC_AS_GENERAL desc\n",
+				iface_no, altno);
+			return NULL;
+		}
+
+		format = le16_to_cpu(as->wFormatTag); /* remember the format value */
+
+		iterm = snd_usb_find_input_terminal_descriptor(ctrl_intf,
+							       as->bTerminalLink,
+							       protocol);
+		if (iterm) {
+			num_channels = iterm->bNrChannels;
+			chconfig = le16_to_cpu(iterm->wChannelConfig);
+		}
+	} else { /* UAC_VERSION_2 */
+		struct uac2_input_terminal_descriptor *input_term;
+		struct uac2_output_terminal_descriptor *output_term;
+		struct uac2_as_header_descriptor *as =
+			snd_usb_find_csint_desc(alts->extra, alts->extralen,
+						NULL, UAC_AS_GENERAL);
+
+		if (!as) {
+			dev_err(&dev->dev,
+				"%u:%d : UAC_AS_GENERAL descriptor not found\n",
+				iface_no, altno);
+			return NULL;
+		}
+
+		if (as->bLength < sizeof(*as)) {
+			dev_err(&dev->dev,
+				"%u:%d : invalid UAC_AS_GENERAL desc\n",
+				iface_no, altno);
+			return NULL;
+		}
+
+		num_channels = as->bNrChannels;
+		format = le32_to_cpu(as->bmFormats);
+		chconfig = le32_to_cpu(as->bmChannelConfig);
+
+		/*
+		 * lookup the terminal associated to this interface
+		 * to extract the clock
+		 */
+		input_term = snd_usb_find_input_terminal_descriptor(ctrl_intf,
+								    as->bTerminalLink,
+								    protocol);
+		if (input_term) {
+			clock = input_term->bCSourceID;
+			if (!chconfig && (num_channels == input_term->bNrChannels))
+				chconfig = le32_to_cpu(input_term->bmChannelConfig);
+			goto found_clock;
+		}
+
+		output_term = snd_usb_find_output_terminal_descriptor(ctrl_intf,
+								      as->bTerminalLink,
+								      protocol);
+		if (output_term) {
+			clock = output_term->bCSourceID;
+			goto found_clock;
+		}
+
+		dev_err(&dev->dev,
+			"%u:%d : bogus bTerminalLink %d\n",
+			iface_no, altno, as->bTerminalLink);
+		return NULL;
+	}
+
+found_clock:
+	/* get format type */
+	fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+				      NULL, UAC_FORMAT_TYPE);
+	if (!fmt) {
+		dev_err(&dev->dev,
+			"%u:%d : no UAC_FORMAT_TYPE desc\n",
+			iface_no, altno);
+		return NULL;
+	}
+	if (((protocol == UAC_VERSION_1) && (fmt->bLength < 8))
+			|| ((protocol == UAC_VERSION_2) &&
+					(fmt->bLength < 6))) {
+		dev_err(&dev->dev,
+			"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
+			iface_no, altno);
+		return NULL;
+	}
+
+	/*
+	 * Blue Microphones workaround: The last altsetting is
+	 * identical with the previous one, except for a larger
+	 * packet size, but is actually a mislabeled two-channel
+	 * setting; ignore it.
+	 *
+	 * Part 2: analyze quirk flag and format
+	 */
+	if (bm_quirk && fmt->bNrChannels == 1 && fmt->bSubframeSize == 2)
+		return NULL;
+
+	fp = audio_format_alloc_init(chip, alts, protocol, iface_no,
+				     altset_idx, altno, num_channels, clock);
+	if (!fp)
+		return ERR_PTR(-ENOMEM);
+
+	fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol,
+						       iface_no);
+
+	/* some quirks for attributes here */
+	snd_usb_audioformat_attributes_quirk(chip, fp, stream);
+
+	/* ok, let's parse further... */
+	if (snd_usb_parse_audio_format(chip, fp, format,
+					fmt, stream) < 0) {
+		audioformat_free(fp);
+		return NULL;
+	}
+
+	/* Create chmap */
+	if (fp->channels != num_channels)
+		chconfig = 0;
+
+	fp->chmap = convert_chmap(fp->channels, chconfig, protocol);
+
+	return fp;
+}
+
+static struct audioformat *
+snd_usb_get_audioformat_uac3(struct snd_usb_audio *chip,
+			     struct usb_host_interface *alts,
+			     struct snd_usb_power_domain **pd_out,
+			     int iface_no, int altset_idx,
+			     int altno, int stream)
+{
+	struct usb_device *dev = chip->dev;
+	struct uac3_input_terminal_descriptor *input_term;
+	struct uac3_output_terminal_descriptor *output_term;
+	struct uac3_cluster_header_descriptor *cluster;
+	struct uac3_as_header_descriptor *as = NULL;
+	struct uac3_hc_descriptor_header hc_header;
+	struct usb_host_interface *ctrl_intf;
+	struct snd_pcm_chmap_elem *chmap;
+	struct snd_usb_power_domain *pd;
+	unsigned char badd_profile;
+	u64 badd_formats = 0;
+	unsigned int num_channels;
+	struct audioformat *fp;
+	u16 cluster_id, wLength, cluster_wLength;
+	int clock = 0;
+	int err;
+
+	badd_profile = chip->badd_profile;
+	ctrl_intf = snd_usb_find_ctrl_interface(chip, iface_no);
+
+	if (badd_profile >= UAC3_FUNCTION_SUBCLASS_GENERIC_IO) {
+		unsigned int maxpacksize =
+			le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+
+		switch (maxpacksize) {
+		default:
+			dev_err(&dev->dev,
+				"%u:%d : incorrect wMaxPacketSize for BADD profile\n",
+				iface_no, altno);
+			return NULL;
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_MONO_16:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_MONO_16:
+			badd_formats = SNDRV_PCM_FMTBIT_S16_LE;
+			num_channels = 1;
+			break;
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_MONO_24:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_MONO_24:
+			badd_formats = SNDRV_PCM_FMTBIT_S24_3LE;
+			num_channels = 1;
+			break;
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_STEREO_16:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_STEREO_16:
+			badd_formats = SNDRV_PCM_FMTBIT_S16_LE;
+			num_channels = 2;
+			break;
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_STEREO_24:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_STEREO_24:
+			badd_formats = SNDRV_PCM_FMTBIT_S24_3LE;
+			num_channels = 2;
+			break;
+		}
+
+		chmap = kzalloc_obj(*chmap);
+		if (!chmap)
+			return ERR_PTR(-ENOMEM);
+
+		if (num_channels == 1) {
+			chmap->map[0] = SNDRV_CHMAP_MONO;
+		} else {
+			chmap->map[0] = SNDRV_CHMAP_FL;
+			chmap->map[1] = SNDRV_CHMAP_FR;
+		}
+
+		chmap->channels = num_channels;
+		clock = UAC3_BADD_CS_ID9;
+		goto found_clock;
+	}
+
+	as = snd_usb_find_csint_desc(alts->extra, alts->extralen,
+				     NULL, UAC_AS_GENERAL);
+	if (!as) {
+		dev_err(&dev->dev,
+			"%u:%d : UAC_AS_GENERAL descriptor not found\n",
+			iface_no, altno);
+		return NULL;
+	}
+
+	if (as->bLength < sizeof(*as)) {
+		dev_err(&dev->dev,
+			"%u:%d : invalid UAC_AS_GENERAL desc\n",
+			iface_no, altno);
+		return NULL;
+	}
+
+	cluster_id = le16_to_cpu(as->wClusterDescrID);
+	if (!cluster_id) {
+		dev_err(&dev->dev,
+			"%u:%d : no cluster descriptor\n",
+			iface_no, altno);
+		return NULL;
+	}
+
+	/*
+	 * Get number of channels and channel map through
+	 * High Capability Cluster Descriptor
+	 *
+	 * First step: get High Capability header and
+	 * read size of Cluster Descriptor
+	 */
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_rcvctrlpipe(chip->dev, 0),
+			UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			cluster_id,
+			snd_usb_ctrl_intf(ctrl_intf),
+			&hc_header, sizeof(hc_header));
+	if (err < 0)
+		return ERR_PTR(err);
+	else if (err != sizeof(hc_header)) {
+		dev_err(&dev->dev,
+			"%u:%d : can't get High Capability descriptor\n",
+			iface_no, altno);
+		return ERR_PTR(-EIO);
+	}
+
+	/*
+	 * Second step: allocate needed amount of memory
+	 * and request Cluster Descriptor
+	 */
+	wLength = le16_to_cpu(hc_header.wLength);
+	if (wLength < sizeof(*cluster))
+		return NULL;
+	cluster = kzalloc(wLength, GFP_KERNEL);
+	if (!cluster)
+		return ERR_PTR(-ENOMEM);
+	err = snd_usb_ctl_msg(chip->dev,
+			usb_rcvctrlpipe(chip->dev, 0),
+			UAC3_CS_REQ_HIGH_CAPABILITY_DESCRIPTOR,
+			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+			cluster_id,
+			snd_usb_ctrl_intf(ctrl_intf),
+			cluster, wLength);
+	if (err < 0) {
+		kfree(cluster);
+		return ERR_PTR(err);
+	} else if (err != wLength) {
+		dev_err(&dev->dev,
+			"%u:%d : can't get Cluster Descriptor\n",
+			iface_no, altno);
+		kfree(cluster);
+		return ERR_PTR(-EIO);
+	}
+
+	cluster_wLength = le16_to_cpu(cluster->wLength);
+	if (cluster_wLength < sizeof(*cluster) ||
+	    cluster_wLength > wLength) {
+		dev_err(&dev->dev,
+			"%u:%d : invalid Cluster Descriptor size\n",
+			iface_no, altno);
+		kfree(cluster);
+		return ERR_PTR(-EIO);
+	}
+
+	num_channels = cluster->bNrChannels;
+	chmap = convert_chmap_v3(cluster);
+	kfree(cluster);
+
+	/*
+	 * lookup the terminal associated to this interface
+	 * to extract the clock
+	 */
+	input_term = snd_usb_find_input_terminal_descriptor(ctrl_intf,
+							    as->bTerminalLink,
+							    UAC_VERSION_3);
+	if (input_term) {
+		clock = input_term->bCSourceID;
+		goto found_clock;
+	}
+
+	output_term = snd_usb_find_output_terminal_descriptor(ctrl_intf,
+							      as->bTerminalLink,
+							      UAC_VERSION_3);
+	if (output_term) {
+		clock = output_term->bCSourceID;
+		goto found_clock;
+	}
+
+	dev_err(&dev->dev, "%u:%d : bogus bTerminalLink %d\n",
+			iface_no, altno, as->bTerminalLink);
+	kfree(chmap);
+	return NULL;
+
+found_clock:
+	fp = audio_format_alloc_init(chip, alts, UAC_VERSION_3, iface_no,
+				     altset_idx, altno, num_channels, clock);
+	if (!fp) {
+		kfree(chmap);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	fp->chmap = chmap;
+
+	if (badd_profile >= UAC3_FUNCTION_SUBCLASS_GENERIC_IO) {
+		fp->attributes = 0; /* No attributes */
+
+		fp->fmt_type = UAC_FORMAT_TYPE_I;
+		fp->formats = badd_formats;
+
+		fp->nr_rates = 0;	/* SNDRV_PCM_RATE_CONTINUOUS */
+		fp->rate_min = UAC3_BADD_SAMPLING_RATE;
+		fp->rate_max = UAC3_BADD_SAMPLING_RATE;
+		fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
+
+		pd = kzalloc_obj(*pd);
+		if (!pd) {
+			audioformat_free(fp);
+			return NULL;
+		}
+		pd->pd_id = (stream == SNDRV_PCM_STREAM_PLAYBACK) ?
+					UAC3_BADD_PD_ID10 : UAC3_BADD_PD_ID11;
+		pd->pd_d1d0_rec = UAC3_BADD_PD_RECOVER_D1D0;
+		pd->pd_d2d0_rec = UAC3_BADD_PD_RECOVER_D2D0;
+		pd->ctrl_iface = ctrl_intf;
+
+	} else {
+		fp->attributes = parse_uac_endpoint_attributes(chip, alts,
+							       UAC_VERSION_3,
+							       iface_no);
+
+		pd = snd_usb_find_power_domain(ctrl_intf,
+					       as->bTerminalLink);
+
+		/* ok, let's parse further... */
+		if (snd_usb_parse_audio_format_v3(chip, fp, as, stream) < 0) {
+			kfree(pd);
+			audioformat_free(fp);
+			return NULL;
+		}
+	}
+
+	*pd_out = pd;
+
+	return fp;
+}
+
+static int __snd_usb_parse_audio_interface(struct snd_usb_audio *chip,
+					   int iface_no,
+					   bool *has_non_pcm, bool non_pcm)
+{
+	struct usb_device *dev;
+	struct usb_interface *iface;
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	int i, altno, err, stream;
+	struct audioformat *fp = NULL;
+	bool set_iface_first;
+	int num, protocol;
+
+	dev = chip->dev;
+
+	/* parse the interface's altsettings */
+	iface = usb_ifnum_to_if(dev, iface_no);
+
+	num = iface->num_altsetting;
+
+	/*
+	 * Dallas DS4201 workaround: It presents 5 altsettings, but the last
+	 * one misses syncpipe, and does not produce any sound.
+	 */
+	if (chip->usb_id == USB_ID(0x04fa, 0x4201) && num >= 4)
+		num = 4;
+
+	for (i = 0; i < num; i++) {
+		alts = &iface->altsetting[i];
+		altsd = get_iface_desc(alts);
+		protocol = altsd->bInterfaceProtocol;
+		/* skip invalid one */
+		if (((altsd->bInterfaceClass != USB_CLASS_AUDIO ||
+		      (altsd->bInterfaceSubClass != USB_SUBCLASS_AUDIOSTREAMING &&
+		       altsd->bInterfaceSubClass != USB_SUBCLASS_VENDOR_SPEC)) &&
+		     altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC) ||
+		    altsd->bNumEndpoints < 1 ||
+		    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) == 0)
+			continue;
+		/* must be isochronous */
+		if ((get_endpoint(alts, 0)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) !=
+		    USB_ENDPOINT_XFER_ISOC)
+			continue;
+		/* check direction */
+		stream = (get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN) ?
+			SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
+		altno = altsd->bAlternateSetting;
+
+		if (snd_usb_apply_interface_quirk(chip, iface_no, altno))
+			continue;
+
+		/* pd may be allocated at snd_usb_get_audioformat_uac3() and
+		 * assigned at snd_usb_add_audio_stream(); otherwise it'll be
+		 * freed automatically by cleanup at each loop.
+		 */
+		struct snd_usb_power_domain *pd __free(kfree) = NULL;
+
+		/*
+		 * Roland audio streaming interfaces are marked with protocols
+		 * 0/1/2, but are UAC 1 compatible.
+		 */
+		if (USB_ID_VENDOR(chip->usb_id) == 0x0582 &&
+		    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
+		    protocol <= 2)
+			protocol = UAC_VERSION_1;
+
+		switch (protocol) {
+		default:
+			dev_dbg(&dev->dev, "%u:%d: unknown interface protocol %#02x, assuming v1\n",
+				iface_no, altno, protocol);
+			protocol = UAC_VERSION_1;
+			fallthrough;
+		case UAC_VERSION_1:
+		case UAC_VERSION_2: {
+			int bm_quirk = 0;
+
+			/*
+			 * Blue Microphones workaround: The last altsetting is
+			 * identical with the previous one, except for a larger
+			 * packet size, but is actually a mislabeled two-channel
+			 * setting; ignore it.
+			 *
+			 * Part 1: prepare quirk flag
+			 */
+			if (altno == 2 && num == 3 &&
+			    fp && fp->altsetting == 1 && fp->channels == 1 &&
+			    fp->formats == SNDRV_PCM_FMTBIT_S16_LE &&
+			    protocol == UAC_VERSION_1 &&
+			    le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) ==
+							fp->maxpacksize * 2)
+				bm_quirk = 1;
+
+			fp = snd_usb_get_audioformat_uac12(chip, alts, protocol,
+							   iface_no, i, altno,
+							   stream, bm_quirk);
+			break;
+		}
+		case UAC_VERSION_3:
+			fp = snd_usb_get_audioformat_uac3(chip, alts, &pd,
+						iface_no, i, altno, stream);
+			break;
+		}
+
+		if (!fp)
+			continue;
+		else if (IS_ERR(fp))
+			return PTR_ERR(fp);
+
+		if (fp->fmt_type != UAC_FORMAT_TYPE_I)
+			*has_non_pcm = true;
+		if ((fp->fmt_type == UAC_FORMAT_TYPE_I) == non_pcm) {
+			audioformat_free(fp);
+			fp = NULL;
+			continue;
+		}
+
+		snd_usb_audioformat_set_sync_ep(chip, fp);
+
+		dev_dbg(&dev->dev, "%u:%d: add audio endpoint %#x\n", iface_no, altno, fp->endpoint);
+		err = snd_usb_add_audio_stream(chip, stream, fp, &pd);
+		if (err < 0) {
+			audioformat_free(fp);
+			return err;
+		}
+
+		/* add endpoints */
+		err = snd_usb_add_endpoint(chip, fp->endpoint,
+					   SND_USB_ENDPOINT_TYPE_DATA);
+		if (err < 0)
+			return err;
+
+		if (fp->sync_ep) {
+			err = snd_usb_add_endpoint(chip, fp->sync_ep,
+						   fp->implicit_fb ?
+						   SND_USB_ENDPOINT_TYPE_DATA :
+						   SND_USB_ENDPOINT_TYPE_SYNC);
+			if (err < 0)
+				return err;
+		}
+
+		set_iface_first = false;
+		if (protocol == UAC_VERSION_1 ||
+		    (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST))
+			set_iface_first = true;
+
+		/* try to set the interface... */
+		if (chip->quirk_flags & QUIRK_FLAG_SKIP_IFACE_SETUP)
+			continue;
+
+		usb_set_interface(chip->dev, iface_no, 0);
+		if (set_iface_first)
+			usb_set_interface(chip->dev, iface_no, altno);
+		snd_usb_init_pitch(chip, fp);
+		snd_usb_init_sample_rate(chip, fp, fp->rate_max);
+		if (!set_iface_first)
+			usb_set_interface(chip->dev, iface_no, altno);
+	}
+	return 0;
+}
+
+int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
+{
+	int err;
+	bool has_non_pcm = false;
+
+	/* parse PCM formats */
+	err = __snd_usb_parse_audio_interface(chip, iface_no, &has_non_pcm, false);
+	if (err < 0)
+		return err;
+
+	if (has_non_pcm) {
+		/* parse non-PCM formats */
+		err = __snd_usb_parse_audio_interface(chip, iface_no, &has_non_pcm, true);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
diff --git a/sound/usb/stream.h b/sound/usb/stream.h
new file mode 100644
index 000000000..61b9a133d
--- /dev/null
+++ b/sound/usb/stream.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_STREAM_H
+#define __USBAUDIO_STREAM_H
+
+int snd_usb_parse_audio_interface(struct snd_usb_audio *chip,
+				  int iface_no);
+
+int snd_usb_add_audio_stream(struct snd_usb_audio *chip,
+			     int stream,
+			     struct audioformat *fp,
+			     struct snd_usb_power_domain **pdptr);
+
+#endif /* __USBAUDIO_STREAM_H */
+
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
new file mode 100644
index 000000000..244364739
--- /dev/null
+++ b/sound/usb/usbaudio.h
@@ -0,0 +1,336 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __USBAUDIO_H
+#define __USBAUDIO_H
+/*
+ *   (Tentative) USB Audio Driver for ALSA
+ *
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
+ */
+
+#include <sound/core.h>
+
+/* handling of USB vendor/product ID pairs as 32-bit numbers */
+#define USB_ID(vendor, product) (((unsigned int)(vendor) << 16) | (product))
+#define USB_ID_VENDOR(id) ((id) >> 16)
+#define USB_ID_PRODUCT(id) ((u16)(id))
+
+/*
+ *
+ */
+
+struct media_device;
+struct media_intf_devnode;
+
+#define MAX_CARD_INTERFACES	16
+
+/*
+ * Structure holding assosiation between Audio Control Interface
+ * and given Streaming or Midi Interface.
+ */
+struct snd_intf_to_ctrl {
+	u8 interface;
+	struct usb_host_interface *ctrl_intf;
+};
+
+struct snd_usb_audio {
+	int index;
+	struct usb_device *dev;
+	struct snd_card *card;
+	struct usb_interface *intf[MAX_CARD_INTERFACES];
+	u32 usb_id;
+	uint16_t quirk_type;
+	struct mutex mutex;
+	unsigned int system_suspend;
+	atomic_t active;
+	atomic_t shutdown;
+	struct snd_refcount usage_count;
+	u64 quirk_flags;
+	unsigned int need_delayed_register:1; /* warn for delayed registration */
+	int num_interfaces;
+	int last_iface;
+	int num_suspended_intf;
+	int sample_rate_read_error;
+
+	int badd_profile;		/* UAC3 BADD profile */
+
+	struct list_head pcm_list;	/* list of pcm streams */
+	struct list_head ep_list;	/* list of audio-related endpoints */
+	struct list_head iface_ref_list; /* list of interface refcounts */
+	struct list_head clock_ref_list; /* list of clock refcounts */
+	int pcm_devs;
+
+	unsigned int num_rawmidis;	/* number of created rawmidi devices */
+	struct list_head midi_list;	/* list of midi interfaces */
+	struct list_head midi_v2_list;	/* list of MIDI 2 interfaces */
+
+	struct list_head mixer_list;	/* list of mixer interfaces */
+
+	int setup;			/* from the 'device_setup' module param */
+	bool generic_implicit_fb;	/* from the 'implicit_fb' module param */
+	bool autoclock;			/* from the 'autoclock' module param */
+
+	bool lowlatency;		/* from the 'lowlatency' module param */
+	struct usb_host_interface *ctrl_intf;	/* the audio control interface */
+	struct media_device *media_dev;
+	struct media_intf_devnode *ctl_intf_media_devnode;
+
+	unsigned int num_intf_to_ctrl;
+	struct snd_intf_to_ctrl intf_to_ctrl[MAX_CARD_INTERFACES];
+};
+
+#define USB_AUDIO_IFACE_UNUSED	((void *)-1L)
+
+#define usb_audio_err(chip, fmt, args...) \
+	dev_err(&(chip)->dev->dev, fmt, ##args)
+#define usb_audio_err_ratelimited(chip, fmt, args...) \
+	dev_err_ratelimited(&(chip)->dev->dev, fmt, ##args)
+#define usb_audio_warn(chip, fmt, args...) \
+	dev_warn(&(chip)->dev->dev, fmt, ##args)
+#define usb_audio_info(chip, fmt, args...) \
+	dev_info(&(chip)->dev->dev, fmt, ##args)
+#define usb_audio_dbg(chip, fmt, args...) \
+	dev_dbg(&(chip)->dev->dev, fmt, ##args)
+
+/*
+ * Information about devices with broken descriptors
+ */
+
+/* special values for .ifnum */
+#define QUIRK_NODEV_INTERFACE		-3	/* return -ENODEV */
+#define QUIRK_NO_INTERFACE		-2
+#define QUIRK_ANY_INTERFACE		-1
+
+enum quirk_type {
+	QUIRK_IGNORE_INTERFACE,
+	QUIRK_COMPOSITE,
+	QUIRK_AUTODETECT,
+	QUIRK_MIDI_STANDARD_INTERFACE,
+	QUIRK_MIDI_FIXED_ENDPOINT,
+	QUIRK_MIDI_YAMAHA,
+	QUIRK_MIDI_ROLAND,
+	QUIRK_MIDI_MIDIMAN,
+	QUIRK_MIDI_NOVATION,
+	QUIRK_MIDI_RAW_BYTES,
+	QUIRK_MIDI_EMAGIC,
+	QUIRK_MIDI_CME,
+	QUIRK_MIDI_AKAI,
+	QUIRK_MIDI_US122L,
+	QUIRK_MIDI_FTDI,
+	QUIRK_MIDI_CH345,
+	QUIRK_AUDIO_STANDARD_INTERFACE,
+	QUIRK_AUDIO_FIXED_ENDPOINT,
+	QUIRK_AUDIO_EDIROL_UAXX,
+	QUIRK_AUDIO_STANDARD_MIXER,
+
+	QUIRK_TYPE_COUNT
+};
+
+struct snd_usb_audio_quirk {
+	const char *vendor_name;
+	const char *product_name;
+	int16_t ifnum;
+	uint16_t type;
+	const void *data;
+};
+
+#define combine_word(s)    ((*(s)) | ((unsigned int)(s)[1] << 8))
+#define combine_triple(s)  (combine_word(s) | ((unsigned int)(s)[2] << 16))
+#define combine_quad(s)    (combine_triple(s) | ((unsigned int)(s)[3] << 24))
+
+int snd_usb_lock_shutdown(struct snd_usb_audio *chip);
+void snd_usb_unlock_shutdown(struct snd_usb_audio *chip);
+
+/* auto-cleanup */
+struct __snd_usb_lock {
+	struct snd_usb_audio *chip;
+	int err;
+};
+
+static inline struct __snd_usb_lock __snd_usb_lock_shutdown(struct snd_usb_audio *chip)
+{
+	struct __snd_usb_lock T = { .chip = chip };
+	T.err = snd_usb_lock_shutdown(chip);
+	return T;
+}
+
+static inline void __snd_usb_unlock_shutdown(struct __snd_usb_lock *lock)
+{
+	if (!lock->err)
+		snd_usb_unlock_shutdown(lock->chip);
+}
+
+DEFINE_CLASS(snd_usb_lock, struct __snd_usb_lock,
+	     __snd_usb_unlock_shutdown(&(_T)), __snd_usb_lock_shutdown(chip),
+	     struct snd_usb_audio *chip)
+
+extern bool snd_usb_use_vmalloc;
+extern bool snd_usb_skip_validation;
+
+/*
+ * Driver behavior quirk flags, stored in chip->quirk_flags
+ *
+ * QUIRK_FLAG_GET_SAMPLE_RATE:
+ *  Skip reading sample rate for devices, as some devices behave inconsistently
+ *  or return error
+ * QUIRK_FLAG_SHARE_MEDIA_DEVICE:
+ *  Create Media Controller API entries
+ * QUIRK_FLAG_ALIGN_TRANSFER:
+ *  Allow alignment on audio sub-slot (channel samples) rather than on audio
+ *  slots (audio frames)
+ * QUIRK_TX_LENGTH:
+ *  Add length specifier to transfers
+ * QUIRK_FLAG_PLAYBACK_FIRST:
+ *  Start playback stream at first even in implement feedback mode
+ * QUIRK_FLAG_SKIP_CLOCK_SELECTOR:
+ *  Skip clock selector setup; the device may reset to invalid state
+ * QUIRK_FLAG_IGNORE_CLOCK_SOURCE:
+ *  Ignore errors from clock source search; i.e. hardcoded clock
+ * QUIRK_FLAG_ITF_USB_DSD_DAC:
+ *  Indicates the device is for ITF-USB DSD based DACs that need a vendor cmd
+ *  to switch between PCM and native DSD mode
+ * QUIRK_FLAG_CTL_MSG_DELAY:
+ *  Add a delay of 20ms at each control message handling
+ * QUIRK_FLAG_CTL_MSG_DELAY_1M:
+ *  Add a delay of 1-2ms at each control message handling
+ * QUIRK_FLAG_CTL_MSG_DELAY_5M:
+ *  Add a delay of 5-6ms at each control message handling
+ * QUIRK_FLAG_IFACE_DELAY:
+ *  Add a delay of 50ms at each interface setup
+ * QUIRK_FLAG_VALIDATE_RATES:
+ *  Perform sample rate validations at probe
+ * QUIRK_FLAG_DISABLE_AUTOSUSPEND:
+ *  Disable runtime PM autosuspend
+ * QUIRK_FLAG_IGNORE_CTL_ERROR:
+ *  Ignore errors for mixer access
+ * QUIRK_FLAG_DSD_RAW:
+ *  Support generic DSD raw U32_BE format
+ * QUIRK_FLAG_SET_IFACE_FIRST:
+ *  Set up the interface at first like UAC1
+ * QUIRK_FLAG_GENERIC_IMPLICIT_FB
+ *  Apply the generic implicit feedback sync mode (same as implicit_fb=1 option)
+ * QUIRK_FLAG_SKIP_IMPLICIT_FB
+ *  Don't apply implicit feedback sync mode
+ * QUIRK_FLAG_IFACE_SKIP_CLOSE
+ *  Don't closed interface during setting sample rate
+ * QUIRK_FLAG_FORCE_IFACE_RESET
+ *  Force an interface reset whenever stopping & restarting a stream
+ *  (e.g. after xrun)
+ * QUIRK_FLAG_FIXED_RATE
+ *  Do not set PCM rate (frequency) when only one rate is available
+ *  for the given endpoint.
+ * QUIRK_FLAG_MIC_RES_16 and QUIRK_FLAG_MIC_RES_384
+ *  Set the fixed resolution for Mic Capture Volume (mostly for webcams)
+ * QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE
+ *  Set minimum volume control value as mute for devices where the lowest
+ *  playback value represents muted state instead of minimum audible volume
+ * QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE
+ *  Similar to QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE, but for capture streams
+ * QUIRK_FLAG_SKIP_IFACE_SETUP
+ *  Skip the probe-time interface setup (usb_set_interface,
+ *  init_pitch, init_sample_rate); redundant with
+ *  snd_usb_endpoint_prepare() at stream-open time
+ * QUIRK_FLAG_MIXER_PLAYBACK_LINEAR_VOL
+ *  Set linear volume mapping for devices where the playback volume control
+ *  value is mapped to voltage (instead of dB) level linearly. In short:
+ *  x(raw) = (raw - raw_min) / (raw_max - raw_min); V(x) = k * x;
+ *  dB(x) = 20 * log10(x). Overrides QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE
+ * QUIRK_FLAG_MIXER_CAPTURE_LINEAR_VOL
+ *  Similar to QUIRK_FLAG_MIXER_PLAYBACK_LINEAR_VOL, but for capture streams.
+ *  Overrides QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE
+ * QUIRK_FLAG_IFB_SILENCE_ON_EMPTY
+ *  In implicit feedback mode, when an entire capture URB returns with
+ *  all iso_frame_desc[i].status != 0 (bytes==0), do not silently return
+ *  from snd_usb_handle_sync_urb. Instead fall through and enqueue a
+ *  packet_info containing only size-0 packets, so the OUT ring keeps
+ *  moving (emits silence). Needed by Behringer Flow 8 (1397:050c).
+ * QUIRK_FLAG_MIXER_GET_CUR_OK
+ *  On some devices, whether their GET_CUR being sticky depends on whether
+ *  hotpluggable components are present. When the hotpluggable components are
+ *  missing on probe, their GET_CUR behavior is classified as broken. Set the
+ *  flag to prevent the heuristics from gating GET_CUR.
+ * QUIRK_FLAG_PLAYBACK_URB_FIXUP
+ *  Set URB_ISO_ASAP flag for isochronous URBs and force nurbs to MAX_URBS.
+ *  This is needed for devices that exhibit boot-time audio stuttering due
+ *  to insufficient buffer depth combined with xHCI scheduling variability.
+ *  The larger buffer (MAX_URBS = 12, ~64ms) absorbs system scheduling
+ *  jitter during boot, while URB_ISO_ASAP ensures consistent xHCI scheduling.
+ * QUIRK_FLAG_ALWAYS_SET_RATE
+ *  Issue SET_CUR for the sample rate even when the clock already reports the
+ *  requested rate.  A device advertising a single rate is otherwise never sent
+ *  the request at all, and some require it before streaming will start.
+ */
+
+enum {
+	QUIRK_TYPE_GET_SAMPLE_RATE		= 0,
+	QUIRK_TYPE_SHARE_MEDIA_DEVICE		= 1,
+	QUIRK_TYPE_ALIGN_TRANSFER		= 2,
+	QUIRK_TYPE_TX_LENGTH			= 3,
+	QUIRK_TYPE_PLAYBACK_FIRST		= 4,
+	QUIRK_TYPE_SKIP_CLOCK_SELECTOR		= 5,
+	QUIRK_TYPE_IGNORE_CLOCK_SOURCE		= 6,
+	QUIRK_TYPE_ITF_USB_DSD_DAC		= 7,
+	QUIRK_TYPE_CTL_MSG_DELAY		= 8,
+	QUIRK_TYPE_CTL_MSG_DELAY_1M		= 9,
+	QUIRK_TYPE_CTL_MSG_DELAY_5M		= 10,
+	QUIRK_TYPE_IFACE_DELAY			= 11,
+	QUIRK_TYPE_VALIDATE_RATES		= 12,
+	QUIRK_TYPE_DISABLE_AUTOSUSPEND		= 13,
+	QUIRK_TYPE_IGNORE_CTL_ERROR		= 14,
+	QUIRK_TYPE_DSD_RAW			= 15,
+	QUIRK_TYPE_SET_IFACE_FIRST		= 16,
+	QUIRK_TYPE_GENERIC_IMPLICIT_FB		= 17,
+	QUIRK_TYPE_SKIP_IMPLICIT_FB		= 18,
+	QUIRK_TYPE_IFACE_SKIP_CLOSE		= 19,
+	QUIRK_TYPE_FORCE_IFACE_RESET		= 20,
+	QUIRK_TYPE_FIXED_RATE			= 21,
+	QUIRK_TYPE_MIC_RES_16			= 22,
+	QUIRK_TYPE_MIC_RES_384			= 23,
+	QUIRK_TYPE_MIXER_PLAYBACK_MIN_MUTE	= 24,
+	QUIRK_TYPE_MIXER_CAPTURE_MIN_MUTE	= 25,
+	QUIRK_TYPE_SKIP_IFACE_SETUP		= 26,
+	QUIRK_TYPE_MIXER_PLAYBACK_LINEAR_VOL	= 27,
+	QUIRK_TYPE_MIXER_CAPTURE_LINEAR_VOL	= 28,
+	QUIRK_TYPE_IFB_SILENCE_ON_EMPTY		= 29,
+	QUIRK_TYPE_MIXER_GET_CUR_OK		= 30,
+	QUIRK_TYPE_PLAYBACK_URB_FIXUP		= 31,
+	QUIRK_TYPE_ALWAYS_SET_RATE		= 32,
+/* Please also edit snd_usb_audio_quirk_flag_names and alsa-configuration.rst */
+};
+
+#define QUIRK_FLAG(x)	BIT_U64(QUIRK_TYPE_ ## x)
+
+#define QUIRK_FLAG_GET_SAMPLE_RATE		QUIRK_FLAG(GET_SAMPLE_RATE)
+#define QUIRK_FLAG_SHARE_MEDIA_DEVICE		QUIRK_FLAG(SHARE_MEDIA_DEVICE)
+#define QUIRK_FLAG_ALIGN_TRANSFER		QUIRK_FLAG(ALIGN_TRANSFER)
+#define QUIRK_FLAG_TX_LENGTH			QUIRK_FLAG(TX_LENGTH)
+#define QUIRK_FLAG_PLAYBACK_FIRST		QUIRK_FLAG(PLAYBACK_FIRST)
+#define QUIRK_FLAG_SKIP_CLOCK_SELECTOR		QUIRK_FLAG(SKIP_CLOCK_SELECTOR)
+#define QUIRK_FLAG_IGNORE_CLOCK_SOURCE		QUIRK_FLAG(IGNORE_CLOCK_SOURCE)
+#define QUIRK_FLAG_ITF_USB_DSD_DAC		QUIRK_FLAG(ITF_USB_DSD_DAC)
+#define QUIRK_FLAG_CTL_MSG_DELAY		QUIRK_FLAG(CTL_MSG_DELAY)
+#define QUIRK_FLAG_CTL_MSG_DELAY_1M		QUIRK_FLAG(CTL_MSG_DELAY_1M)
+#define QUIRK_FLAG_CTL_MSG_DELAY_5M		QUIRK_FLAG(CTL_MSG_DELAY_5M)
+#define QUIRK_FLAG_IFACE_DELAY			QUIRK_FLAG(IFACE_DELAY)
+#define QUIRK_FLAG_VALIDATE_RATES		QUIRK_FLAG(VALIDATE_RATES)
+#define QUIRK_FLAG_DISABLE_AUTOSUSPEND		QUIRK_FLAG(DISABLE_AUTOSUSPEND)
+#define QUIRK_FLAG_IGNORE_CTL_ERROR		QUIRK_FLAG(IGNORE_CTL_ERROR)
+#define QUIRK_FLAG_DSD_RAW			QUIRK_FLAG(DSD_RAW)
+#define QUIRK_FLAG_SET_IFACE_FIRST		QUIRK_FLAG(SET_IFACE_FIRST)
+#define QUIRK_FLAG_GENERIC_IMPLICIT_FB		QUIRK_FLAG(GENERIC_IMPLICIT_FB)
+#define QUIRK_FLAG_SKIP_IMPLICIT_FB		QUIRK_FLAG(SKIP_IMPLICIT_FB)
+#define QUIRK_FLAG_IFACE_SKIP_CLOSE		QUIRK_FLAG(IFACE_SKIP_CLOSE)
+#define QUIRK_FLAG_FORCE_IFACE_RESET		QUIRK_FLAG(FORCE_IFACE_RESET)
+#define QUIRK_FLAG_FIXED_RATE			QUIRK_FLAG(FIXED_RATE)
+#define QUIRK_FLAG_MIC_RES_16			QUIRK_FLAG(MIC_RES_16)
+#define QUIRK_FLAG_MIC_RES_384			QUIRK_FLAG(MIC_RES_384)
+#define QUIRK_FLAG_MIXER_PLAYBACK_MIN_MUTE	QUIRK_FLAG(MIXER_PLAYBACK_MIN_MUTE)
+#define QUIRK_FLAG_MIXER_CAPTURE_MIN_MUTE	QUIRK_FLAG(MIXER_CAPTURE_MIN_MUTE)
+#define QUIRK_FLAG_SKIP_IFACE_SETUP		QUIRK_FLAG(SKIP_IFACE_SETUP)
+#define QUIRK_FLAG_MIXER_PLAYBACK_LINEAR_VOL	QUIRK_FLAG(MIXER_PLAYBACK_LINEAR_VOL)
+#define QUIRK_FLAG_MIXER_CAPTURE_LINEAR_VOL	QUIRK_FLAG(MIXER_CAPTURE_LINEAR_VOL)
+#define QUIRK_FLAG_IFB_SILENCE_ON_EMPTY		QUIRK_FLAG(IFB_SILENCE_ON_EMPTY)
+#define QUIRK_FLAG_MIXER_GET_CUR_OK		QUIRK_FLAG(MIXER_GET_CUR_OK)
+#define QUIRK_FLAG_PLAYBACK_URB_FIXUP		QUIRK_FLAG(PLAYBACK_URB_FIXUP)
+#define QUIRK_FLAG_ALWAYS_SET_RATE		QUIRK_FLAG(ALWAYS_SET_RATE)
+
+#endif /* __USBAUDIO_H */
diff --git a/sound/usb/usx2y/Makefile b/sound/usb/usx2y/Makefile
new file mode 100644
index 000000000..9db87ae39
--- /dev/null
+++ b/sound/usb/usx2y/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+snd-usb-usx2y-y := usbusx2y.o usX2Yhwdep.o usx2yhwdeppcm.o
+snd-usb-us122l-y := us122l.o
+snd-usb-us144mkii-y := us144mkii.o us144mkii_pcm.o us144mkii_playback.o us144mkii_capture.o us144mkii_midi.o us144mkii_controls.o
+
+obj-$(CONFIG_SND_USB_USX2Y) += snd-usb-usx2y.o
+obj-$(CONFIG_SND_USB_US122L) += snd-usb-us122l.o
+obj-$(CONFIG_SND_USB_US144MKII) += snd-usb-us144mkii.o
\ No newline at end of file
diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c
new file mode 100644
index 000000000..a5db0d044
--- /dev/null
+++ b/sound/usb/usx2y/us122l.c
@@ -0,0 +1,685 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2007, 2008 Karsten Wiese <fzu@wemgehoertderstaat.de>
+ */
+
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/module.h>
+#include <sound/core.h>
+#include <sound/hwdep.h>
+#include <sound/pcm.h>
+#include <sound/initval.h>
+#define MODNAME "US122L"
+#include "usb_stream.c"
+#include "../usbaudio.h"
+#include "../midi.h"
+#include "us122l.h"
+
+MODULE_AUTHOR("Karsten Wiese <fzu@wemgehoertderstaat.de>");
+MODULE_DESCRIPTION("TASCAM "NAME_ALLCAPS" Version 0.5");
+MODULE_LICENSE("GPL");
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-max */
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* Id for this card */
+							/* Enable this card */
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "Index value for "NAME_ALLCAPS".");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string for "NAME_ALLCAPS".");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "Enable "NAME_ALLCAPS".");
+
+/* driver_info flags */
+#define US122L_FLAG_US144	BIT(0)
+
+static int snd_us122l_card_used[SNDRV_CARDS];
+
+static int us122l_create_usbmidi(struct snd_card *card)
+{
+	static const struct snd_usb_midi_endpoint_info quirk_data = {
+		.out_ep = 4,
+		.in_ep = 3,
+		.out_cables =	0x001,
+		.in_cables =	0x001
+	};
+	static const struct snd_usb_audio_quirk quirk = {
+		.vendor_name =	"US122L",
+		.product_name =	NAME_ALLCAPS,
+		.ifnum =	1,
+		.type = QUIRK_MIDI_US122L,
+		.data = &quirk_data
+	};
+	struct usb_device *dev = US122L(card)->dev;
+	struct usb_interface *iface = usb_ifnum_to_if(dev, 1);
+
+	return snd_usbmidi_create(card, iface,
+				  &US122L(card)->midi_list, &quirk);
+}
+
+static int us144_create_usbmidi(struct snd_card *card)
+{
+	static const struct snd_usb_midi_endpoint_info quirk_data = {
+		.out_ep = 4,
+		.in_ep = 3,
+		.out_cables =	0x001,
+		.in_cables =	0x001
+	};
+	static const struct snd_usb_audio_quirk quirk = {
+		.vendor_name =	"US144",
+		.product_name =	NAME_ALLCAPS,
+		.ifnum =	0,
+		.type = QUIRK_MIDI_US122L,
+		.data = &quirk_data
+	};
+	struct usb_device *dev = US122L(card)->dev;
+	struct usb_interface *iface = usb_ifnum_to_if(dev, 0);
+
+	return snd_usbmidi_create(card, iface,
+				  &US122L(card)->midi_list, &quirk);
+}
+
+static void pt_info_set(struct usb_device *dev, u8 v)
+{
+	usb_control_msg_send(dev, 0, 'I',
+			     USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			     v, 0, NULL, 0, 1000, GFP_NOIO);
+}
+
+static vm_fault_t usb_stream_hwdep_vm_fault(struct vm_fault *vmf)
+{
+	unsigned long offset;
+	struct page *page;
+	void *vaddr;
+	struct us122l *us122l = vmf->vma->vm_private_data;
+	struct usb_stream *s;
+
+	guard(mutex)(&us122l->mutex);
+	s = us122l->sk.s;
+	if (!s)
+		return VM_FAULT_SIGBUS;
+
+	offset = vmf->pgoff << PAGE_SHIFT;
+	if (offset < PAGE_ALIGN(s->read_size)) {
+		vaddr = (char *)s + offset;
+	} else {
+		offset -= PAGE_ALIGN(s->read_size);
+		if (offset >= PAGE_ALIGN(s->write_size))
+			return VM_FAULT_SIGBUS;
+
+		vaddr = us122l->sk.write_page + offset;
+	}
+	page = virt_to_page(vaddr);
+
+	get_page(page);
+
+	vmf->page = page;
+
+	return 0;
+}
+
+
+static const struct vm_operations_struct usb_stream_hwdep_vm_ops = {
+	.fault = usb_stream_hwdep_vm_fault,
+};
+
+static int usb_stream_hwdep_open(struct snd_hwdep *hw, struct file *file)
+{
+	struct us122l	*us122l = hw->private_data;
+	struct usb_interface *iface;
+
+	if (hw->used >= 2)
+		return -EBUSY;
+
+	if (!us122l->first)
+		us122l->first = file;
+
+	if (us122l->is_us144) {
+		iface = usb_ifnum_to_if(us122l->dev, 0);
+		usb_autopm_get_interface(iface);
+	}
+	iface = usb_ifnum_to_if(us122l->dev, 1);
+	usb_autopm_get_interface(iface);
+	return 0;
+}
+
+static int usb_stream_hwdep_release(struct snd_hwdep *hw, struct file *file)
+{
+	struct us122l	*us122l = hw->private_data;
+	struct usb_interface *iface;
+
+	if (us122l->is_us144) {
+		iface = usb_ifnum_to_if(us122l->dev, 0);
+		usb_autopm_put_interface(iface);
+	}
+	iface = usb_ifnum_to_if(us122l->dev, 1);
+	usb_autopm_put_interface(iface);
+	if (us122l->first == file)
+		us122l->first = NULL;
+	guard(mutex)(&us122l->mutex);
+	if (us122l->master == file)
+		us122l->master = us122l->slave;
+
+	us122l->slave = NULL;
+	return 0;
+}
+
+static int usb_stream_hwdep_mmap(struct snd_hwdep *hw,
+				 struct file *filp, struct vm_area_struct *area)
+{
+	unsigned long	size = area->vm_end - area->vm_start;
+	struct us122l	*us122l = hw->private_data;
+	unsigned long offset;
+	struct usb_stream *s;
+	bool read;
+
+	offset = area->vm_pgoff << PAGE_SHIFT;
+	guard(mutex)(&us122l->mutex);
+	s = us122l->sk.s;
+	read = offset < s->read_size;
+	if (read) {
+		if (area->vm_flags & VM_WRITE)
+			return -EPERM;
+		vm_flags_clear(area, VM_MAYWRITE);
+	}
+	/* if userspace tries to mmap beyond end of our buffer, fail */
+	if (size > PAGE_ALIGN(read ? s->read_size : s->write_size)) {
+		dev_warn(hw->card->dev, "%s: size %lu > %u\n", __func__,
+			 size, read ? s->read_size : s->write_size);
+		return -EINVAL;
+	}
+
+	area->vm_ops = &usb_stream_hwdep_vm_ops;
+	vm_flags_set(area, VM_DONTDUMP);
+	if (!read)
+		vm_flags_set(area, VM_DONTEXPAND);
+	area->vm_private_data = us122l;
+	return 0;
+}
+
+static __poll_t usb_stream_hwdep_poll(struct snd_hwdep *hw,
+					  struct file *file, poll_table *wait)
+{
+	struct us122l	*us122l = hw->private_data;
+	unsigned int	*polled;
+	__poll_t	mask;
+
+	poll_wait(file, &us122l->sk.sleep, wait);
+
+	mask = EPOLLIN | EPOLLOUT | EPOLLWRNORM | EPOLLERR;
+	if (mutex_trylock(&us122l->mutex)) {
+		struct usb_stream *s = us122l->sk.s;
+
+		if (s && s->state == usb_stream_ready) {
+			if (us122l->first == file)
+				polled = &s->periods_polled;
+			else
+				polled = &us122l->second_periods_polled;
+			if (*polled != s->periods_done) {
+				*polled = s->periods_done;
+				mask = EPOLLIN | EPOLLOUT | EPOLLWRNORM;
+			} else {
+				mask = 0;
+			}
+		}
+		mutex_unlock(&us122l->mutex);
+	}
+	return mask;
+}
+
+static void us122l_stop(struct us122l *us122l)
+{
+	struct list_head *p;
+
+	list_for_each(p, &us122l->midi_list)
+		snd_usbmidi_input_stop(p);
+
+	usb_stream_stop(&us122l->sk);
+	usb_stream_free(&us122l->sk);
+}
+
+static int us122l_set_sample_rate(struct usb_device *dev, int rate)
+{
+	unsigned int ep = 0x81;
+	unsigned char data[3];
+	int err;
+
+	data[0] = rate;
+	data[1] = rate >> 8;
+	data[2] = rate >> 16;
+	err = usb_control_msg_send(dev, 0, UAC_SET_CUR,
+				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
+				   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep, data, 3,
+				   1000, GFP_NOIO);
+	if (err)
+		dev_err(&dev->dev, "%d: cannot set freq %d to ep 0x%x\n",
+			dev->devnum, rate, ep);
+	return err;
+}
+
+static bool us122l_start(struct us122l *us122l,
+			 unsigned int rate, unsigned int period_frames)
+{
+	struct list_head *p;
+	int err;
+	unsigned int use_packsize = 0;
+	bool success = false;
+
+	if (us122l->dev->speed == USB_SPEED_HIGH) {
+		/* The us-122l's descriptor defaults to iso max_packsize 78,
+		   which isn't needed for samplerates <= 48000.
+		   Lets save some memory:
+		*/
+		switch (rate) {
+		case 44100:
+			use_packsize = 36;
+			break;
+		case 48000:
+			use_packsize = 42;
+			break;
+		case 88200:
+			use_packsize = 72;
+			break;
+		}
+	}
+	if (!usb_stream_new(&us122l->sk, us122l->dev, 1, 2,
+			    rate, use_packsize, period_frames, 6))
+		goto out;
+
+	err = us122l_set_sample_rate(us122l->dev, rate);
+	if (err < 0) {
+		us122l_stop(us122l);
+		dev_err(&us122l->dev->dev, "us122l_set_sample_rate error\n");
+		goto out;
+	}
+	err = usb_stream_start(&us122l->sk);
+	if (err < 0) {
+		us122l_stop(us122l);
+		dev_err(&us122l->dev->dev, "%s error %i\n", __func__, err);
+		goto out;
+	}
+	list_for_each(p, &us122l->midi_list)
+		snd_usbmidi_input_start(p);
+	success = true;
+out:
+	return success;
+}
+
+static int usb_stream_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
+				  unsigned int cmd, unsigned long arg)
+{
+	struct usb_stream_config cfg;
+	struct us122l *us122l = hw->private_data;
+	struct usb_stream *s;
+	unsigned int min_period_frames;
+	int err = 0;
+	bool high_speed;
+
+	if (cmd != SNDRV_USB_STREAM_IOCTL_SET_PARAMS)
+		return -ENOTTY;
+
+	if (copy_from_user(&cfg, (void __user *)arg, sizeof(cfg)))
+		return -EFAULT;
+
+	if (cfg.version != USB_STREAM_INTERFACE_VERSION)
+		return -ENXIO;
+
+	high_speed = us122l->dev->speed == USB_SPEED_HIGH;
+	if ((cfg.sample_rate != 44100 && cfg.sample_rate != 48000  &&
+	     (!high_speed ||
+	      (cfg.sample_rate != 88200 && cfg.sample_rate != 96000))) ||
+	    cfg.frame_size != 6 ||
+	    cfg.period_frames > 0x3000)
+		return -EINVAL;
+
+	switch (cfg.sample_rate) {
+	case 44100:
+		min_period_frames = 48;
+		break;
+	case 48000:
+		min_period_frames = 52;
+		break;
+	default:
+		min_period_frames = 104;
+		break;
+	}
+	if (!high_speed)
+		min_period_frames <<= 1;
+	if (cfg.period_frames < min_period_frames)
+		return -EINVAL;
+
+	snd_power_wait(hw->card);
+
+	guard(mutex)(&us122l->mutex);
+	s = us122l->sk.s;
+	if (!us122l->master) {
+		us122l->master = file;
+	} else if (us122l->master != file) {
+		if (!s || memcmp(&cfg, &s->cfg, sizeof(cfg))) {
+			err = -EIO;
+			goto unlock;
+		}
+		us122l->slave = file;
+	}
+	if (!s || memcmp(&cfg, &s->cfg, sizeof(cfg)) ||
+	    s->state == usb_stream_xrun) {
+		us122l_stop(us122l);
+		if (!us122l_start(us122l, cfg.sample_rate, cfg.period_frames))
+			err = -EIO;
+		else
+			err = 1;
+	}
+unlock:
+	wake_up_all(&us122l->sk.sleep);
+	return err;
+}
+
+#define SND_USB_STREAM_ID "USB STREAM"
+static int usb_stream_hwdep_new(struct snd_card *card)
+{
+	int err;
+	struct snd_hwdep *hw;
+	struct usb_device *dev = US122L(card)->dev;
+
+	err = snd_hwdep_new(card, SND_USB_STREAM_ID, 0, &hw);
+	if (err < 0)
+		return err;
+
+	hw->iface = SNDRV_HWDEP_IFACE_USB_STREAM;
+	hw->private_data = US122L(card);
+	hw->ops.open = usb_stream_hwdep_open;
+	hw->ops.release = usb_stream_hwdep_release;
+	hw->ops.ioctl = usb_stream_hwdep_ioctl;
+	hw->ops.ioctl_compat = usb_stream_hwdep_ioctl;
+	hw->ops.mmap = usb_stream_hwdep_mmap;
+	hw->ops.poll = usb_stream_hwdep_poll;
+
+	sprintf(hw->name, "/dev/bus/usb/%03d/%03d/hwdeppcm",
+		dev->bus->busnum, dev->devnum);
+	return 0;
+}
+
+static bool us122l_create_card(struct snd_card *card)
+{
+	int err;
+	struct us122l *us122l = US122L(card);
+
+	if (us122l->is_us144) {
+		err = usb_set_interface(us122l->dev, 0, 1);
+		if (err) {
+			dev_err(card->dev, "usb_set_interface error\n");
+			return false;
+		}
+	}
+	err = usb_set_interface(us122l->dev, 1, 1);
+	if (err) {
+		dev_err(card->dev, "usb_set_interface error\n");
+		return false;
+	}
+
+	pt_info_set(us122l->dev, 0x11);
+	pt_info_set(us122l->dev, 0x10);
+
+	if (!us122l_start(us122l, 44100, 256))
+		return false;
+
+	if (us122l->is_us144)
+		err = us144_create_usbmidi(card);
+	else
+		err = us122l_create_usbmidi(card);
+	if (err < 0) {
+		dev_err(card->dev, "us122l_create_usbmidi error %i\n", err);
+		goto stop;
+	}
+	err = usb_stream_hwdep_new(card);
+	if (err < 0) {
+		/* release the midi resources */
+		struct list_head *p;
+
+		list_for_each(p, &us122l->midi_list)
+			snd_usbmidi_disconnect(p);
+
+		goto stop;
+	}
+	return true;
+
+stop:
+	us122l_stop(us122l);
+	return false;
+}
+
+static void snd_us122l_free(struct snd_card *card)
+{
+	struct us122l	*us122l = US122L(card);
+	int		index = us122l->card_index;
+
+	if (index >= 0 && index < SNDRV_CARDS)
+		snd_us122l_card_used[index] = 0;
+}
+
+static int usx2y_create_card(struct usb_device *device,
+			     struct usb_interface *intf,
+			     struct snd_card **cardp,
+			     unsigned long flags)
+{
+	int		dev;
+	struct snd_card *card;
+	int err;
+
+	for (dev = 0; dev < SNDRV_CARDS; ++dev)
+		if (enable[dev] && !snd_us122l_card_used[dev])
+			break;
+	if (dev >= SNDRV_CARDS)
+		return -ENODEV;
+	err = snd_card_new(&intf->dev, index[dev], id[dev], THIS_MODULE,
+			   sizeof(struct us122l), &card);
+	if (err < 0)
+		return err;
+	snd_us122l_card_used[US122L(card)->card_index = dev] = 1;
+	card->private_free = snd_us122l_free;
+	US122L(card)->dev = device;
+	mutex_init(&US122L(card)->mutex);
+	US122L(card)->sk.dev = device;
+	init_waitqueue_head(&US122L(card)->sk.sleep);
+	US122L(card)->is_us144 = flags & US122L_FLAG_US144;
+	INIT_LIST_HEAD(&US122L(card)->midi_list);
+	strscpy(card->driver, "USB "NAME_ALLCAPS"");
+	sprintf(card->shortname, "TASCAM "NAME_ALLCAPS"");
+	sprintf(card->longname, "%s (%x:%x if %d at %03d/%03d)",
+		card->shortname,
+		le16_to_cpu(device->descriptor.idVendor),
+		le16_to_cpu(device->descriptor.idProduct),
+		0,
+		US122L(card)->dev->bus->busnum,
+		US122L(card)->dev->devnum
+		);
+	*cardp = card;
+	return 0;
+}
+
+static int us122l_usb_probe(struct usb_interface *intf,
+			    const struct usb_device_id *device_id,
+			    struct snd_card **cardp)
+{
+	struct usb_device *device = interface_to_usbdev(intf);
+	struct snd_card *card;
+	int err;
+
+	err = usx2y_create_card(device, intf, &card, device_id->driver_info);
+	if (err < 0)
+		return err;
+
+	if (!us122l_create_card(card)) {
+		snd_card_free(card);
+		return -EINVAL;
+	}
+
+	err = snd_card_register(card);
+	if (err < 0) {
+		snd_card_free(card);
+		return err;
+	}
+
+	*cardp = card;
+	return 0;
+}
+
+static int snd_us122l_probe(struct usb_interface *intf,
+			    const struct usb_device_id *id)
+{
+	struct usb_device *device = interface_to_usbdev(intf);
+	struct snd_card *card;
+	int err;
+
+	if (id->driver_info & US122L_FLAG_US144 &&
+			device->speed == USB_SPEED_HIGH) {
+		dev_err(&device->dev, "disable ehci-hcd to run US-144\n");
+		return -ENODEV;
+	}
+
+	if (intf->cur_altsetting->desc.bInterfaceNumber != 1)
+		return 0;
+
+	err = us122l_usb_probe(intf, id, &card);
+	if (err < 0)
+		return err;
+
+	usb_set_intfdata(intf, card);
+	return 0;
+}
+
+static void snd_us122l_disconnect(struct usb_interface *intf)
+{
+	struct snd_card *card;
+	struct us122l *us122l;
+	struct list_head *p;
+
+	card = usb_get_intfdata(intf);
+	if (!card)
+		return;
+
+	snd_card_disconnect(card);
+
+	us122l = US122L(card);
+	scoped_guard(mutex, &us122l->mutex) {
+		us122l_stop(us122l);
+	}
+
+	/* release the midi resources */
+	list_for_each(p, &us122l->midi_list) {
+		snd_usbmidi_disconnect(p);
+	}
+
+	snd_card_free_when_closed(card);
+}
+
+static int snd_us122l_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct snd_card *card;
+	struct us122l *us122l;
+	struct list_head *p;
+
+	card = usb_get_intfdata(intf);
+	if (!card)
+		return 0;
+	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
+
+	us122l = US122L(card);
+	if (!us122l)
+		return 0;
+
+	list_for_each(p, &us122l->midi_list)
+		snd_usbmidi_input_stop(p);
+
+	guard(mutex)(&us122l->mutex);
+	usb_stream_stop(&us122l->sk);
+
+	return 0;
+}
+
+static int snd_us122l_resume(struct usb_interface *intf)
+{
+	struct snd_card *card;
+	struct us122l *us122l;
+	struct list_head *p;
+	int err;
+
+	card = usb_get_intfdata(intf);
+	if (!card)
+		return 0;
+
+	us122l = US122L(card);
+	if (!us122l)
+		return 0;
+
+	guard(mutex)(&us122l->mutex);
+	/* needed, doesn't restart without: */
+	if (us122l->is_us144) {
+		err = usb_set_interface(us122l->dev, 0, 1);
+		if (err) {
+			dev_err(&us122l->dev->dev, "usb_set_interface error\n");
+			goto unlock;
+		}
+	}
+	err = usb_set_interface(us122l->dev, 1, 1);
+	if (err) {
+		dev_err(&us122l->dev->dev, "usb_set_interface error\n");
+		goto unlock;
+	}
+
+	pt_info_set(us122l->dev, 0x11);
+	pt_info_set(us122l->dev, 0x10);
+
+	err = us122l_set_sample_rate(us122l->dev,
+				     us122l->sk.s->cfg.sample_rate);
+	if (err < 0) {
+		dev_err(&us122l->dev->dev, "us122l_set_sample_rate error\n");
+		goto unlock;
+	}
+	err = usb_stream_start(&us122l->sk);
+	if (err)
+		goto unlock;
+
+	list_for_each(p, &us122l->midi_list)
+		snd_usbmidi_input_start(p);
+unlock:
+	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
+	return err;
+}
+
+static const struct usb_device_id snd_us122l_usb_id_table[] = {
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	0x0644,
+		.idProduct =	USB_ID_US122L
+	},
+	{	/* US-144 only works at USB1.1! Disable module ehci-hcd. */
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	0x0644,
+		.idProduct =	USB_ID_US144,
+		.driver_info =	US122L_FLAG_US144
+	},
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	0x0644,
+		.idProduct =	USB_ID_US122MKII
+	},
+	{ /* terminator */ }
+};
+MODULE_DEVICE_TABLE(usb, snd_us122l_usb_id_table);
+
+static struct usb_driver snd_us122l_usb_driver = {
+	.name =		"snd-usb-us122l",
+	.probe =	snd_us122l_probe,
+	.disconnect =	snd_us122l_disconnect,
+	.suspend =	snd_us122l_suspend,
+	.resume =	snd_us122l_resume,
+	.reset_resume =	snd_us122l_resume,
+	.id_table =	snd_us122l_usb_id_table,
+	.supports_autosuspend = 1
+};
+
+module_usb_driver(snd_us122l_usb_driver);
diff --git a/sound/usb/usx2y/us122l.h b/sound/usb/usx2y/us122l.h
new file mode 100644
index 000000000..8e59b78d3
--- /dev/null
+++ b/sound/usb/usx2y/us122l.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef US122L_H
+#define US122L_H
+
+
+struct us122l {
+	struct usb_device	*dev;
+	int			card_index;
+	int			stride;
+	struct usb_stream_kernel sk;
+
+	struct mutex		mutex;
+	struct file		*first;
+	unsigned int		second_periods_polled;
+	struct file		*master;
+	struct file		*slave;
+	struct list_head	midi_list;
+
+	bool			is_us144;
+};
+
+
+#define US122L(c) ((struct us122l *)(c)->private_data)
+
+#define NAME_ALLCAPS "US-122L"
+
+#define USB_ID_US122L 0x800E
+#define USB_ID_US144 0x800F
+#define USB_ID_US122MKII 0x8021
+#define USB_ID_US144MKII 0x8020
+
+#endif
diff --git a/sound/usb/usx2y/us144mkii.c b/sound/usb/usx2y/us144mkii.c
new file mode 100644
index 000000000..58ef23146
--- /dev/null
+++ b/sound/usb/usx2y/us144mkii.c
@@ -0,0 +1,629 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
+/*
+ * ALSA Driver for TASCAM US-144MKII Audio Interface
+ */
+
+#include "us144mkii.h"
+
+MODULE_AUTHOR("Šerif Rami <ramiserifpersia@gmail.com>");
+MODULE_DESCRIPTION("ALSA Driver for TASCAM US-144MKII");
+MODULE_LICENSE("GPL");
+
+/*
+ * Module parameters for ALSA card instantiation.
+ *
+ * These parameters allow users to configure how the ALSA sound card
+ * for the TASCAM US-144MKII is instantiated.
+ *
+ * @param index: Array of integers specifying the ALSA card index for each
+ * device. Defaults to -1 (automatic).
+ * @param id: Array of strings specifying the ALSA card ID for each device.
+ *            Defaults to "US144MKII".
+ * @param enable: Array of booleans to enable or disable each device.
+ *                Defaults to {1, 0, ..., 0} (first device enabled).
+ * @param dev_idx: Internal counter for the number of TASCAM devices probed.
+ */
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
+static bool enable[SNDRV_CARDS] = { 1, [1 ...(SNDRV_CARDS - 1)] = 0 };
+static int dev_idx;
+
+static int tascam_probe(struct usb_interface *intf,
+			const struct usb_device_id *usb_id);
+static void tascam_disconnect(struct usb_interface *intf);
+static int tascam_suspend(struct usb_interface *intf, pm_message_t message);
+static int tascam_resume(struct usb_interface *intf);
+
+void tascam_free_urbs(struct tascam_card *tascam)
+{
+	int i;
+
+	usb_kill_anchored_urbs(&tascam->playback_anchor);
+	for (i = 0; i < NUM_PLAYBACK_URBS; i++) {
+		if (tascam->playback_urbs[i]) {
+			usb_free_coherent(
+				tascam->dev, tascam->playback_urb_alloc_size,
+				tascam->playback_urbs[i]->transfer_buffer,
+				tascam->playback_urbs[i]->transfer_dma);
+			usb_free_urb(tascam->playback_urbs[i]);
+			tascam->playback_urbs[i] = NULL;
+		}
+	}
+
+	usb_kill_anchored_urbs(&tascam->feedback_anchor);
+	for (i = 0; i < NUM_FEEDBACK_URBS; i++) {
+		if (tascam->feedback_urbs[i]) {
+			usb_free_coherent(
+				tascam->dev, tascam->feedback_urb_alloc_size,
+				tascam->feedback_urbs[i]->transfer_buffer,
+				tascam->feedback_urbs[i]->transfer_dma);
+			usb_free_urb(tascam->feedback_urbs[i]);
+			tascam->feedback_urbs[i] = NULL;
+		}
+	}
+
+	usb_kill_anchored_urbs(&tascam->capture_anchor);
+	for (i = 0; i < NUM_CAPTURE_URBS; i++) {
+		if (tascam->capture_urbs[i]) {
+			usb_free_coherent(
+				tascam->dev, tascam->capture_urb_alloc_size,
+				tascam->capture_urbs[i]->transfer_buffer,
+				tascam->capture_urbs[i]->transfer_dma);
+			usb_free_urb(tascam->capture_urbs[i]);
+			tascam->capture_urbs[i] = NULL;
+		}
+	}
+
+	usb_kill_anchored_urbs(&tascam->midi_in_anchor);
+	for (i = 0; i < NUM_MIDI_IN_URBS; i++) {
+		if (tascam->midi_in_urbs[i]) {
+			usb_free_coherent(
+				tascam->dev, MIDI_IN_BUF_SIZE,
+				tascam->midi_in_urbs[i]->transfer_buffer,
+				tascam->midi_in_urbs[i]->transfer_dma);
+			usb_free_urb(tascam->midi_in_urbs[i]);
+			tascam->midi_in_urbs[i] = NULL;
+		}
+	}
+
+	usb_kill_anchored_urbs(&tascam->midi_out_anchor);
+	for (i = 0; i < NUM_MIDI_OUT_URBS; i++) {
+		if (tascam->midi_out_urbs[i]) {
+			usb_free_coherent(
+				tascam->dev, MIDI_OUT_BUF_SIZE,
+				tascam->midi_out_urbs[i]->transfer_buffer,
+				tascam->midi_out_urbs[i]->transfer_dma);
+			usb_free_urb(tascam->midi_out_urbs[i]);
+			tascam->midi_out_urbs[i] = NULL;
+		}
+	}
+
+	kfree(tascam->capture_routing_buffer);
+	tascam->capture_routing_buffer = NULL;
+	kfree(tascam->capture_decode_dst_block);
+	tascam->capture_decode_dst_block = NULL;
+	kfree(tascam->capture_decode_raw_block);
+	tascam->capture_decode_raw_block = NULL;
+	kfree(tascam->capture_ring_buffer);
+	tascam->capture_ring_buffer = NULL;
+}
+
+int tascam_alloc_urbs(struct tascam_card *tascam)
+{
+	int i;
+	size_t max_packet_size;
+
+	max_packet_size = ((96000 / 8000) + 2) * BYTES_PER_FRAME;
+	tascam->playback_urb_alloc_size =
+		max_packet_size * PLAYBACK_URB_PACKETS;
+
+	for (i = 0; i < NUM_PLAYBACK_URBS; i++) {
+		struct urb *urb =
+			usb_alloc_urb(PLAYBACK_URB_PACKETS, GFP_KERNEL);
+
+		if (!urb)
+			goto error;
+		tascam->playback_urbs[i] = urb;
+
+		urb->transfer_buffer = usb_alloc_coherent(
+			tascam->dev, tascam->playback_urb_alloc_size,
+			GFP_KERNEL, &urb->transfer_dma);
+		if (!urb->transfer_buffer)
+			goto error;
+
+		urb->dev = tascam->dev;
+		urb->pipe = usb_sndisocpipe(tascam->dev, EP_AUDIO_OUT);
+		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
+		urb->interval = 1;
+		urb->context = tascam;
+		urb->complete = playback_urb_complete;
+	}
+
+	tascam->feedback_urb_alloc_size =
+		FEEDBACK_PACKET_SIZE * FEEDBACK_URB_PACKETS;
+
+	for (i = 0; i < NUM_FEEDBACK_URBS; i++) {
+		struct urb *f_urb =
+			usb_alloc_urb(FEEDBACK_URB_PACKETS, GFP_KERNEL);
+
+		if (!f_urb)
+			goto error;
+		tascam->feedback_urbs[i] = f_urb;
+
+		f_urb->transfer_buffer = usb_alloc_coherent(
+			tascam->dev, tascam->feedback_urb_alloc_size,
+			GFP_KERNEL, &f_urb->transfer_dma);
+		if (!f_urb->transfer_buffer)
+			goto error;
+
+		f_urb->dev = tascam->dev;
+		f_urb->pipe =
+			usb_rcvisocpipe(tascam->dev, EP_PLAYBACK_FEEDBACK);
+		f_urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
+		f_urb->interval = 4;
+		f_urb->context = tascam;
+		f_urb->complete = feedback_urb_complete;
+	}
+
+	tascam->capture_urb_alloc_size = CAPTURE_URB_SIZE;
+	for (i = 0; i < NUM_CAPTURE_URBS; i++) {
+		struct urb *c_urb = usb_alloc_urb(0, GFP_KERNEL);
+
+		if (!c_urb)
+			goto error;
+		tascam->capture_urbs[i] = c_urb;
+
+		c_urb->transfer_buffer = usb_alloc_coherent(
+			tascam->dev, tascam->capture_urb_alloc_size, GFP_KERNEL,
+			&c_urb->transfer_dma);
+		if (!c_urb->transfer_buffer)
+			goto error;
+
+		usb_fill_bulk_urb(c_urb, tascam->dev,
+				  usb_rcvbulkpipe(tascam->dev, EP_AUDIO_IN),
+				  c_urb->transfer_buffer,
+				  tascam->capture_urb_alloc_size,
+				  capture_urb_complete, tascam);
+		c_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	}
+
+	/* MIDI URB and buffer allocation */
+	for (i = 0; i < NUM_MIDI_IN_URBS; i++) {
+		struct urb *m_urb = usb_alloc_urb(0, GFP_KERNEL);
+
+		if (!m_urb)
+			goto error;
+		tascam->midi_in_urbs[i] = m_urb;
+		m_urb->transfer_buffer =
+			usb_alloc_coherent(tascam->dev, MIDI_IN_BUF_SIZE,
+					   GFP_KERNEL, &m_urb->transfer_dma);
+		if (!m_urb->transfer_buffer)
+			goto error;
+		usb_fill_bulk_urb(m_urb, tascam->dev,
+				  usb_rcvbulkpipe(tascam->dev, EP_MIDI_IN),
+				  m_urb->transfer_buffer, MIDI_IN_BUF_SIZE,
+				  tascam_midi_in_urb_complete, tascam);
+		m_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	}
+
+	for (i = 0; i < NUM_MIDI_OUT_URBS; i++) {
+		struct urb *m_urb = usb_alloc_urb(0, GFP_KERNEL);
+
+		if (!m_urb)
+			goto error;
+		tascam->midi_out_urbs[i] = m_urb;
+		m_urb->transfer_buffer =
+			usb_alloc_coherent(tascam->dev, MIDI_OUT_BUF_SIZE,
+					   GFP_KERNEL, &m_urb->transfer_dma);
+		if (!m_urb->transfer_buffer)
+			goto error;
+		usb_fill_bulk_urb(m_urb, tascam->dev,
+				  usb_sndbulkpipe(tascam->dev, EP_MIDI_OUT),
+				  m_urb->transfer_buffer,
+				  0, /* length set later */
+				  tascam_midi_out_urb_complete, tascam);
+		m_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	}
+
+	tascam->capture_ring_buffer =
+		kmalloc(CAPTURE_RING_BUFFER_SIZE, GFP_KERNEL);
+	if (!tascam->capture_ring_buffer)
+		goto error;
+
+	tascam->capture_decode_raw_block =
+		kmalloc(RAW_BYTES_PER_DECODE_BLOCK, GFP_KERNEL);
+	if (!tascam->capture_decode_raw_block)
+		goto error;
+
+	tascam->capture_decode_dst_block =
+		kmalloc(FRAMES_PER_DECODE_BLOCK * DECODED_CHANNELS_PER_FRAME *
+				DECODED_SAMPLE_SIZE,
+			GFP_KERNEL);
+	if (!tascam->capture_decode_dst_block)
+		goto error;
+
+	tascam->capture_routing_buffer =
+		kmalloc(FRAMES_PER_DECODE_BLOCK * DECODED_CHANNELS_PER_FRAME *
+				DECODED_SAMPLE_SIZE,
+			GFP_KERNEL);
+	if (!tascam->capture_routing_buffer)
+		goto error;
+
+	return 0;
+
+error:
+	dev_err(tascam->card->dev, "Failed to allocate URBs\n");
+	tascam_free_urbs(tascam);
+	return -ENOMEM;
+}
+
+void tascam_stop_work_handler(struct work_struct *work)
+{
+	struct tascam_card *tascam =
+		container_of(work, struct tascam_card, stop_work);
+
+	usb_kill_anchored_urbs(&tascam->playback_anchor);
+	usb_kill_anchored_urbs(&tascam->feedback_anchor);
+	usb_kill_anchored_urbs(&tascam->capture_anchor);
+	atomic_set(&tascam->active_urbs, 0);
+}
+
+/*
+ * tascam_card_private_free() - Frees private data associated with the sound
+ * card.
+ * @card: Pointer to the ALSA sound card instance.
+ *
+ * This function is called when the sound card is being freed. It releases
+ * resources allocated for the tascam_card structure, including the MIDI
+ * input FIFO and decrements the USB device reference count.
+ */
+static void tascam_card_private_free(struct snd_card *card)
+{
+	struct tascam_card *tascam = card->private_data;
+
+	if (tascam) {
+		kfifo_free(&tascam->midi_in_fifo);
+		if (tascam->dev) {
+			usb_put_dev(tascam->dev);
+			tascam->dev = NULL;
+		}
+	}
+}
+
+/*
+ * tascam_suspend() - Handles device suspension.
+ * @intf: The USB interface being suspended.
+ * @message: Power management message.
+ *
+ * This function is called when the device is suspended. It stops all active
+ * streams, kills all URBs, and sends a vendor-specific deep sleep command
+ * to the device to ensure a stable low-power state.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct tascam_card *tascam = usb_get_intfdata(intf);
+
+	if (!tascam)
+		return 0;
+
+	snd_pcm_suspend_all(tascam->pcm);
+
+	cancel_work_sync(&tascam->stop_work);
+	cancel_work_sync(&tascam->capture_work);
+	cancel_work_sync(&tascam->midi_in_work);
+	cancel_work_sync(&tascam->midi_out_work);
+	cancel_work_sync(&tascam->stop_pcm_work);
+	usb_kill_anchored_urbs(&tascam->playback_anchor);
+	usb_kill_anchored_urbs(&tascam->capture_anchor);
+	usb_kill_anchored_urbs(&tascam->feedback_anchor);
+	usb_kill_anchored_urbs(&tascam->midi_in_anchor);
+	usb_kill_anchored_urbs(&tascam->midi_out_anchor);
+
+	dev_info(&intf->dev, "sending deep sleep command\n");
+	int err = usb_control_msg(tascam->dev, usb_sndctrlpipe(tascam->dev, 0),
+				  VENDOR_REQ_DEEP_SLEEP, RT_H2D_VENDOR_DEV,
+				  0x0000, 0x0000, NULL, 0, USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		dev_err(&intf->dev, "deep sleep command failed: %d\n", err);
+
+	return 0;
+}
+
+/*
+ * tascam_resume() - Handles device resumption from suspend.
+ * @intf: The USB interface being resumed.
+ *
+ * This function is called when the device resumes from suspend. It
+ * re-establishes the active USB interface settings and re-configures the sample
+ * rate if it was previously active.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+static int tascam_resume(struct usb_interface *intf)
+{
+	struct tascam_card *tascam = usb_get_intfdata(intf);
+	int err;
+
+	if (!tascam)
+		return 0;
+
+	dev_info(&intf->dev, "resuming TASCAM US-144MKII\n");
+
+	/*
+	 * The device requires a full re-initialization sequence upon resume.
+	 * First, re-establish the active USB interface settings.
+	 */
+	err = usb_set_interface(tascam->dev, 0, 1);
+	if (err < 0) {
+		dev_err(&intf->dev,
+			"resume: failed to set alt setting on intf 0: %d\n",
+			err);
+		return err;
+	}
+	err = usb_set_interface(tascam->dev, 1, 1);
+	if (err < 0) {
+		dev_err(&intf->dev,
+			"resume: failed to set alt setting on intf 1: %d\n",
+			err);
+		return err;
+	}
+
+	/* Re-configure the sample rate if one was previously active */
+	if (tascam->current_rate > 0)
+		us144mkii_configure_device_for_rate(tascam,
+						    tascam->current_rate);
+
+	return 0;
+}
+
+static void tascam_error_timer(struct timer_list *t)
+{
+	struct tascam_card *tascam =
+		container_of(t, struct tascam_card, error_timer);
+
+	if (atomic_read(&tascam->midi_in_active))
+		schedule_work(&tascam->midi_in_work);
+	if (atomic_read(&tascam->midi_out_active))
+		schedule_work(&tascam->midi_out_work);
+}
+
+/*
+ * tascam_probe() - Probes for the TASCAM US-144MKII device.
+ * @intf: The USB interface being probed.
+ * @usb_id: The USB device ID.
+ *
+ * This function is the entry point for the USB driver when a matching device
+ * is found. It performs initial device setup, including:
+ * - Checking for the second interface (MIDI) and associating it.
+ * - Performing a vendor-specific handshake with the device.
+ * - Setting alternate settings for USB interfaces.
+ * - Creating and registering the ALSA sound card, PCM device, and MIDI device.
+ * - Allocating and initializing URBs for audio and MIDI transfers.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+static int tascam_probe(struct usb_interface *intf,
+			const struct usb_device_id *usb_id)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	struct snd_card *card;
+	struct tascam_card *tascam;
+	int err;
+
+	if (dev->speed != USB_SPEED_HIGH)
+		dev_info(
+			&dev->dev,
+			"Device is connected to a USB 1.1 port, this is not supported.\n");
+
+	/* The device has two interfaces; we drive both from this driver. */
+	if (intf->cur_altsetting->desc.bInterfaceNumber == 1) {
+		struct usb_interface *intf_zero = usb_ifnum_to_if(dev, 0);
+
+		if (!intf_zero)
+			return -ENODEV;
+		tascam = usb_get_intfdata(intf_zero);
+		if (tascam) {
+			usb_set_intfdata(intf, tascam);
+			tascam->iface1 = intf;
+		}
+		return 0; /* Let the core handle this interface */
+	}
+
+	if (dev_idx >= SNDRV_CARDS) {
+		dev_err(&dev->dev, "Too many TASCAM devices present");
+		return -ENODEV;
+	}
+
+	if (!enable[dev_idx]) {
+		dev_info(&dev->dev, "TASCAM US-144MKII device disabled");
+		return -ENOENT;
+	}
+
+	char *handshake_buf __free(kfree) =
+		kmalloc(1, GFP_KERNEL);
+	if (!handshake_buf)
+		return -ENOMEM;
+
+	/* Perform vendor-specific handshake */
+	err = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+			      VENDOR_REQ_MODE_CONTROL, RT_D2H_VENDOR_DEV,
+			      MODE_VAL_HANDSHAKE_READ, 0x0000, handshake_buf, 1,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0) {
+		dev_err(&dev->dev, "Handshake read failed with %d\n", err);
+		return err;
+	}
+
+	if (handshake_buf[0] != 0x12 && handshake_buf[0] != 0x16 &&
+	    handshake_buf[0] != 0x30 && handshake_buf[0] != 0x32) {
+		dev_err(&dev->dev, "Unexpected handshake value: 0x%x\n",
+			handshake_buf[0]);
+		return -ENODEV;
+	}
+
+	/* Set alternate settings to enable audio/MIDI endpoints */
+	err = usb_set_interface(dev, 0, 1);
+	if (err < 0) {
+		dev_err(&dev->dev,
+			"Failed to set alt setting 1 on interface 0: %d\n",
+			err);
+		return err;
+	}
+
+	err = usb_set_interface(dev, 1, 1);
+	if (err < 0) {
+		dev_err(&dev->dev,
+			"Failed to set alt setting 1 on interface 1: %d\n",
+			err);
+		return err;
+	}
+
+	err = snd_card_new(&dev->dev, index[dev_idx], id[dev_idx], THIS_MODULE,
+			   sizeof(struct tascam_card), &card);
+	if (err < 0) {
+		dev_err(&dev->dev, "Failed to create sound card instance\n");
+		return err;
+	}
+
+	tascam = card->private_data;
+	card->private_free = tascam_card_private_free;
+	tascam->dev = usb_get_dev(dev);
+	tascam->card = card;
+	tascam->iface0 = intf;
+	tascam->digital_out_source = 1;
+	tascam->capture_34_source = 1;
+
+	spin_lock_init(&tascam->lock);
+	spin_lock_init(&tascam->midi_in_lock);
+	spin_lock_init(&tascam->midi_out_lock);
+	init_usb_anchor(&tascam->playback_anchor);
+	init_usb_anchor(&tascam->capture_anchor);
+	init_usb_anchor(&tascam->feedback_anchor);
+	init_usb_anchor(&tascam->midi_in_anchor);
+	init_usb_anchor(&tascam->midi_out_anchor);
+
+	timer_setup(&tascam->error_timer, tascam_error_timer, 0);
+
+	INIT_WORK(&tascam->stop_work, tascam_stop_work_handler);
+	INIT_WORK(&tascam->stop_pcm_work, tascam_stop_pcm_work_handler);
+	INIT_WORK(&tascam->capture_work, tascam_capture_work_handler);
+	init_completion(&tascam->midi_out_drain_completion);
+
+	if (kfifo_alloc(&tascam->midi_in_fifo, MIDI_IN_FIFO_SIZE, GFP_KERNEL)) {
+		snd_card_free(card);
+		return -ENOMEM;
+	}
+
+	strscpy(card->driver, DRIVER_NAME, sizeof(card->driver));
+	if (le16_to_cpu(dev->descriptor.idProduct) == USB_PID_TASCAM_US144) {
+		strscpy(card->shortname, "TASCAM US-144",
+			sizeof(card->shortname));
+	} else if (le16_to_cpu(dev->descriptor.idProduct) == USB_PID_TASCAM_US144MKII) {
+		strscpy(card->shortname, "TASCAM US-144MKII",
+			sizeof(card->shortname));
+	} else {
+		strscpy(card->shortname, "TASCAM Unknown",
+			sizeof(card->shortname));
+	}
+	snprintf(card->longname, sizeof(card->longname), "%s (%04x:%04x) at %s",
+		 card->shortname, USB_VID_TASCAM, dev->descriptor.idProduct,
+		 dev_name(&dev->dev));
+
+	err = snd_pcm_new(card, "US144MKII PCM", 0, 1, 1, &tascam->pcm);
+	if (err < 0)
+		goto free_card;
+	tascam->pcm->private_data = tascam;
+	strscpy(tascam->pcm->name, "US144MKII PCM", sizeof(tascam->pcm->name));
+
+	err = tascam_init_pcm(tascam->pcm);
+	if (err < 0)
+		goto free_card;
+
+	err = tascam_create_midi(tascam);
+	if (err < 0)
+		goto free_card;
+
+	err = tascam_create_controls(tascam);
+	if (err < 0)
+		goto free_card;
+
+	err = tascam_alloc_urbs(tascam);
+	if (err < 0)
+		goto free_card;
+
+	err = snd_card_register(card);
+	if (err < 0)
+		goto free_card;
+
+	usb_set_intfdata(intf, tascam);
+
+	dev_idx++;
+	return 0;
+
+free_card:
+	tascam_free_urbs(tascam);
+	snd_card_free(card);
+	return err;
+}
+
+/*
+ * tascam_disconnect() - Disconnects the TASCAM US-144MKII device.
+ * @intf: The USB interface being disconnected.
+ *
+ * This function is called when the device is disconnected from the system.
+ * It cleans up all allocated resources, including killing URBs, freeing
+ * the sound card, and releasing memory.
+ */
+static void tascam_disconnect(struct usb_interface *intf)
+{
+	struct tascam_card *tascam = usb_get_intfdata(intf);
+
+	if (!tascam)
+		return;
+
+	if (intf->cur_altsetting->desc.bInterfaceNumber == 0) {
+		snd_card_disconnect(tascam->card);
+
+		/*
+		 * Kill the URBs before cancelling the work, so a late URB
+		 * completion cannot re-arm a work that then runs after
+		 * snd_card_free().
+		 */
+		usb_kill_anchored_urbs(&tascam->playback_anchor);
+		usb_kill_anchored_urbs(&tascam->capture_anchor);
+		usb_kill_anchored_urbs(&tascam->feedback_anchor);
+		usb_kill_anchored_urbs(&tascam->midi_in_anchor);
+		usb_kill_anchored_urbs(&tascam->midi_out_anchor);
+
+		cancel_work_sync(&tascam->stop_work);
+		cancel_work_sync(&tascam->capture_work);
+		cancel_work_sync(&tascam->midi_in_work);
+		cancel_work_sync(&tascam->midi_out_work);
+		cancel_work_sync(&tascam->stop_pcm_work);
+		timer_delete_sync(&tascam->error_timer);
+		tascam_free_urbs(tascam);
+		snd_card_free(tascam->card);
+		dev_idx--;
+	}
+}
+
+static const struct usb_device_id tascam_usb_ids[] = {
+	{ USB_DEVICE(USB_VID_TASCAM, USB_PID_TASCAM_US144) },
+	{ USB_DEVICE(USB_VID_TASCAM, USB_PID_TASCAM_US144MKII) },
+	{ /* Terminating entry */ }
+};
+MODULE_DEVICE_TABLE(usb, tascam_usb_ids);
+
+static struct usb_driver tascam_alsa_driver = {
+	.name = DRIVER_NAME,
+	.probe = tascam_probe,
+	.disconnect = tascam_disconnect,
+	.suspend = tascam_suspend,
+	.resume = tascam_resume,
+	.id_table = tascam_usb_ids,
+};
+
+module_usb_driver(tascam_alsa_driver);
diff --git a/sound/usb/usx2y/us144mkii.h b/sound/usb/usx2y/us144mkii.h
new file mode 100644
index 000000000..95c4341f0
--- /dev/null
+++ b/sound/usb/usx2y/us144mkii.h
@@ -0,0 +1,367 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
+
+#ifndef __US144MKII_H
+#define __US144MKII_H
+
+#include <linux/kfifo.h>
+#include <linux/timer.h>
+#include <linux/usb.h>
+#include <linux/workqueue.h>
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/rawmidi.h>
+
+#define DRIVER_NAME "us144mkii"
+
+/* --- USB Device Identification --- */
+#define USB_VID_TASCAM 0x0644
+#define USB_PID_TASCAM_US144 0x800f
+#define USB_PID_TASCAM_US144MKII 0x8020
+
+/* --- USB Endpoints (Alternate Setting 1) --- */
+#define EP_PLAYBACK_FEEDBACK 0x81
+#define EP_AUDIO_OUT 0x02
+#define EP_MIDI_IN 0x83
+#define EP_MIDI_OUT 0x04
+#define EP_AUDIO_IN 0x86
+
+/* --- USB Control Message Protocol --- */
+#define RT_H2D_CLASS_EP (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT)
+#define RT_D2H_CLASS_EP (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT)
+#define RT_H2D_VENDOR_DEV (USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE)
+#define RT_D2H_VENDOR_DEV (USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE)
+
+enum uac_request {
+	UAC_SET_CUR = 0x01,
+	UAC_GET_CUR = 0x81,
+};
+
+enum uac_control_selector {
+	UAC_SAMPLING_FREQ_CONTROL = 0x0100,
+};
+
+enum tascam_vendor_request {
+	VENDOR_REQ_REGISTER_WRITE = 0x41,
+	VENDOR_REQ_DEEP_SLEEP = 0x44,
+	VENDOR_REQ_MODE_CONTROL = 0x49,
+};
+
+enum tascam_mode_value {
+	MODE_VAL_HANDSHAKE_READ = 0x0000,
+	MODE_VAL_CONFIG = 0x0010,
+	MODE_VAL_STREAM_START = 0x0030,
+};
+
+#define HANDSHAKE_SUCCESS_VAL 0x12
+
+enum tascam_register {
+	REG_ADDR_UNKNOWN_0D = 0x0d04,
+	REG_ADDR_UNKNOWN_0E = 0x0e00,
+	REG_ADDR_UNKNOWN_0F = 0x0f00,
+	REG_ADDR_RATE_44100 = 0x1000,
+	REG_ADDR_RATE_48000 = 0x1002,
+	REG_ADDR_RATE_88200 = 0x1008,
+	REG_ADDR_RATE_96000 = 0x100a,
+	REG_ADDR_UNKNOWN_11 = 0x110b,
+};
+
+#define REG_VAL_ENABLE 0x0101
+
+/* --- URB Configuration --- */
+#define NUM_PLAYBACK_URBS 4
+#define PLAYBACK_URB_PACKETS 8
+#define NUM_FEEDBACK_URBS 4
+#define FEEDBACK_URB_PACKETS 1
+#define FEEDBACK_PACKET_SIZE 3
+#define NUM_CAPTURE_URBS 8
+#define CAPTURE_URB_SIZE 512
+#define CAPTURE_RING_BUFFER_SIZE (CAPTURE_URB_SIZE * NUM_CAPTURE_URBS * 4)
+#define NUM_MIDI_IN_URBS 4
+#define MIDI_IN_BUF_SIZE 64
+#define MIDI_IN_FIFO_SIZE (MIDI_IN_BUF_SIZE * NUM_MIDI_IN_URBS)
+#define MIDI_OUT_BUF_SIZE 64
+#define NUM_MIDI_OUT_URBS 4
+#define USB_CTRL_TIMEOUT_MS 1000
+#define FEEDBACK_SYNC_LOSS_THRESHOLD 41
+
+/* --- Audio Format Configuration --- */
+#define BYTES_PER_SAMPLE 3
+#define NUM_CHANNELS 4
+#define BYTES_PER_FRAME (NUM_CHANNELS * BYTES_PER_SAMPLE)
+#define FEEDBACK_ACCUMULATOR_SIZE 128
+
+/* --- Capture Decoding Defines --- */
+#define DECODED_CHANNELS_PER_FRAME 4
+#define DECODED_SAMPLE_SIZE 4
+#define FRAMES_PER_DECODE_BLOCK 8
+#define RAW_BYTES_PER_DECODE_BLOCK 512
+
+/**
+ * struct us144mkii_frame_pattern_observer - State for dynamic feedback
+ * patterns.
+ * @sample_rate_khz: The current sample rate in kHz.
+ * @base_feedback_value: The nominal feedback value for the current rate.
+ * @feedback_offset: An offset to align the feedback value range.
+ * @full_frame_patterns: A 2D array of pre-calculated packet size patterns.
+ * @current_index: The current index into the pattern array.
+ * @previous_index: The previous index, used for state tracking.
+ * @sync_locked: A flag indicating if the pattern has locked to the stream.
+ */
+struct us144mkii_frame_pattern_observer {
+	unsigned int sample_rate_khz;
+	unsigned int base_feedback_value;
+	int feedback_offset;
+	unsigned int full_frame_patterns[5][8];
+	unsigned int current_index;
+	unsigned int previous_index;
+	bool sync_locked;
+};
+
+/**
+ * struct tascam_card - Main driver data structure for the TASCAM US-144MKII.
+ * @dev: Pointer to the USB device.
+ * @iface0: Pointer to USB interface 0 (audio).
+ * @iface1: Pointer to USB interface 1 (MIDI).
+ * @card: Pointer to the ALSA sound card instance.
+ * @pcm: Pointer to the ALSA PCM device.
+ * @rmidi: Pointer to the ALSA rawmidi device.
+ *
+ * @playback_substream: Pointer to the active playback PCM substream.
+ * @playback_urbs: Array of URBs for playback.
+ * @playback_urb_alloc_size: Size of allocated buffer for each playback URB.
+ * @feedback_urbs: Array of URBs for feedback.
+ * @feedback_urb_alloc_size: Size of allocated buffer for each feedback URB.
+ * @playback_active: Atomic flag indicating if playback is active.
+ * @playback_frames_consumed: Total frames consumed by playback.
+ * @driver_playback_pos: Current position in the ALSA playback buffer (frames).
+ * @last_period_pos: Last reported period position for playback.
+ *
+ * @capture_substream: Pointer to the active capture PCM substream.
+ * @capture_urbs: Array of URBs for capture.
+ * @capture_urb_alloc_size: Size of allocated buffer for each capture URB.
+ * @capture_active: Atomic flag indicating if capture is active.
+ * @driver_capture_pos: Current position in the ALSA capture buffer (frames).
+ * @capture_frames_processed: Total frames processed for capture.
+ * @last_capture_period_pos: Last reported period position for capture.
+ * @capture_ring_buffer: Ring buffer for raw capture data from USB.
+ * @capture_ring_buffer_read_ptr: Read pointer for the capture ring buffer.
+ * @capture_ring_buffer_write_ptr: Write pointer for the capture ring buffer.
+ * @capture_decode_raw_block: Buffer for a raw 512-byte capture block.
+ * @capture_decode_dst_block: Buffer for decoded 32-bit capture samples.
+ * @capture_routing_buffer: Intermediate buffer for capture routing.
+ * @capture_work: Work struct for deferred capture processing.
+ * @stop_work: Work struct for deferred stream stopping.
+ * @stop_pcm_work: Work struct for stopping PCM due to a fatal error (e.g.
+ * xrun).
+ *
+ * @midi_in_substream: Pointer to the active MIDI input substream.
+ * @midi_out_substream: Pointer to the active MIDI output substream.
+ * @midi_in_urbs: Array of URBs for MIDI input.
+ * @midi_out_urbs: Array of URBs for MIDI output.
+ * @midi_in_active: Atomic flag indicating if MIDI input is active.
+ * @midi_out_active: Atomic flag indicating if MIDI output is active.
+ * @midi_in_fifo: FIFO for raw MIDI input data.
+ * @midi_in_work: Work struct for deferred MIDI input processing.
+ * @midi_out_work: Work struct for deferred MIDI output processing.
+ * @midi_in_lock: Spinlock for MIDI input FIFO.
+ * @midi_out_lock: Spinlock for MIDI output.
+ * @midi_out_urbs_in_flight: Bitmap of MIDI output URBs currently in flight.
+ * @midi_running_status: Stores the last MIDI status byte for running status.
+ * @error_timer: Timer for MIDI error retry logic.
+ *
+ * @lock: Main spinlock for protecting shared driver state.
+ * @active_urbs: Atomic counter for active URBs.
+ * @current_rate: Currently configured sample rate of the device.
+ * @line_out_source: Source for Line Outputs (0: Playback 1-2, 1: Playback 3-4).
+ * @digital_out_source: Source for Digital Outputs (0: Playback 1-2, 1: Playback
+ * 3-4).
+ * @capture_12_source: Source for Capture channels 1-2 (0: Analog In, 1: Digital
+ * In).
+ * @capture_34_source: Source for Capture channels 3-4 (0: Analog In, 1: Digital
+ * In).
+ *
+ * @feedback_accumulator_pattern: Stores the calculated frames per packet for
+ * feedback.
+ * @feedback_pattern_out_idx: Read index for feedback_accumulator_pattern.
+ * @feedback_pattern_in_idx: Write index for feedback_accumulator_pattern.
+ * @feedback_synced: Flag indicating if feedback is synced.
+ * @feedback_consecutive_errors: Counter for consecutive feedback errors.
+ * @feedback_urb_skip_count: Number of feedback URBs to skip initially for
+ * stabilization.
+ * @fpo: Holds the state for the dynamic feedback pattern generation.
+ *
+ * @playback_anchor: USB anchor for playback URBs.
+ * @capture_anchor: USB anchor for capture URBs.
+ * @feedback_anchor: USB anchor for feedback URBs.
+ * @midi_in_anchor: USB anchor for MIDI input URBs.
+ * @midi_out_anchor: USB anchor for MIDI output URBs.
+ */
+struct tascam_card {
+	/* --- Core device pointers --- */
+	struct usb_device *dev;
+	struct usb_interface *iface0;
+	struct usb_interface *iface1;
+	struct snd_card *card;
+	struct snd_pcm *pcm;
+	struct snd_rawmidi *rmidi;
+
+	/* --- PCM Substreams --- */
+	struct snd_pcm_substream *playback_substream;
+	struct snd_pcm_substream *capture_substream;
+
+	/* --- URBs and Anchors --- */
+	struct urb *playback_urbs[NUM_PLAYBACK_URBS];
+	size_t playback_urb_alloc_size;
+	struct urb *feedback_urbs[NUM_FEEDBACK_URBS];
+	size_t feedback_urb_alloc_size;
+	struct urb *capture_urbs[NUM_CAPTURE_URBS];
+	size_t capture_urb_alloc_size;
+	struct urb *midi_in_urbs[NUM_MIDI_IN_URBS];
+	struct urb *midi_out_urbs[NUM_MIDI_OUT_URBS];
+	struct usb_anchor playback_anchor;
+	struct usb_anchor capture_anchor;
+	struct usb_anchor feedback_anchor;
+	struct usb_anchor midi_in_anchor;
+	struct usb_anchor midi_out_anchor;
+
+	/* --- Stream State --- */
+	spinlock_t lock;
+	atomic_t playback_active;
+	atomic_t capture_active;
+	atomic_t active_urbs;
+	int current_rate;
+
+	/* --- Playback State --- */
+	u64 playback_frames_consumed;
+	snd_pcm_uframes_t driver_playback_pos;
+	u64 last_period_pos;
+
+	/* --- Capture State --- */
+	u64 capture_frames_processed;
+	snd_pcm_uframes_t driver_capture_pos;
+	u64 last_capture_period_pos;
+	u8 *capture_ring_buffer;
+	size_t capture_ring_buffer_read_ptr;
+	size_t capture_ring_buffer_write_ptr;
+	u8 *capture_decode_raw_block;
+	s32 *capture_decode_dst_block;
+	s32 *capture_routing_buffer;
+
+	/* --- MIDI State --- */
+	struct snd_rawmidi_substream *midi_in_substream;
+	struct snd_rawmidi_substream *midi_out_substream;
+	atomic_t midi_in_active;
+	atomic_t midi_out_active;
+	struct kfifo midi_in_fifo;
+	spinlock_t midi_in_lock;
+	spinlock_t midi_out_lock;
+	unsigned long midi_out_urbs_in_flight;
+	u8 midi_running_status;
+	struct timer_list error_timer;
+	struct completion midi_out_drain_completion;
+
+	/* --- Feedback Sync State --- */
+	unsigned int feedback_accumulator_pattern[FEEDBACK_ACCUMULATOR_SIZE];
+	unsigned int feedback_pattern_out_idx;
+	unsigned int feedback_pattern_in_idx;
+	bool feedback_synced;
+	unsigned int feedback_consecutive_errors;
+	unsigned int feedback_urb_skip_count;
+	struct us144mkii_frame_pattern_observer fpo;
+
+	/* --- Workqueues --- */
+	struct work_struct stop_work;
+	struct work_struct stop_pcm_work;
+	struct work_struct capture_work;
+	struct work_struct midi_in_work;
+	struct work_struct midi_out_work;
+
+	/* --- Mixer/Routing State --- */
+	unsigned int line_out_source;
+	unsigned int digital_out_source;
+	unsigned int capture_12_source;
+	unsigned int capture_34_source;
+};
+
+/* main.c */
+/**
+ * tascam_free_urbs() - Free all allocated URBs and associated buffers.
+ * @tascam: the tascam_card instance
+ *
+ * This function kills, unlinks, and frees all playback, feedback, capture,
+ * and MIDI URBs, along with their transfer buffers and the capture
+ * ring/decode buffers.
+ */
+void tascam_free_urbs(struct tascam_card *tascam);
+
+/**
+ * tascam_alloc_urbs() - Allocate all URBs and associated buffers.
+ * @tascam: the tascam_card instance
+ *
+ * This function allocates and initializes all URBs for playback, feedback,
+ * capture, and MIDI, as well as the necessary buffers for data processing.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int tascam_alloc_urbs(struct tascam_card *tascam);
+
+/**
+ * tascam_stop_work_handler() - Work handler to stop all active streams.
+ * @work: Pointer to the work_struct.
+ *
+ * This function is scheduled to stop all active URBs (playback, feedback,
+ * capture) and reset the active_urbs counter.
+ */
+void tascam_stop_work_handler(struct work_struct *work);
+
+/* us144mkii_pcm.h */
+#include "us144mkii_pcm.h"
+
+/* us144mkii_midi.c */
+/**
+ * tascam_midi_in_urb_complete() - Completion handler for MIDI IN URBs
+ * @urb: The completed URB.
+ *
+ * This function runs in interrupt context. It places the raw data from the
+ * USB endpoint into a kfifo and schedules a work item to process it later,
+ * ensuring the interrupt handler remains fast.
+ */
+void tascam_midi_in_urb_complete(struct urb *urb);
+
+/**
+ * tascam_midi_out_urb_complete() - Completion handler for MIDI OUT bulk URB.
+ * @urb: The completed URB.
+ *
+ * This function runs in interrupt context. It marks the output URB as no
+ * longer in-flight. It then re-schedules the work handler to check for and
+ * send any more data waiting in the ALSA buffer. This is a safe, non-blocking
+ * way to continue the data transmission chain.
+ */
+void tascam_midi_out_urb_complete(struct urb *urb);
+
+/**
+ * tascam_create_midi() - Create and initialize the ALSA rawmidi device.
+ * @tascam: The driver instance.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int tascam_create_midi(struct tascam_card *tascam);
+
+/* us144mkii_controls.c */
+/**
+ * tascam_create_controls() - Creates and adds ALSA mixer controls for the
+ * device.
+ * @tascam: The driver instance.
+ *
+ * This function registers custom ALSA controls for managing audio routing
+ * (line out source, digital out source, capture 1-2 source, capture 3-4 source)
+ * and displaying the current sample rate.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int tascam_create_controls(struct tascam_card *tascam);
+
+#endif /* __US144MKII_H */
diff --git a/sound/usb/usx2y/us144mkii_capture.c b/sound/usb/usx2y/us144mkii_capture.c
new file mode 100644
index 000000000..d7cdf9e0f
--- /dev/null
+++ b/sound/usb/usx2y/us144mkii_capture.c
@@ -0,0 +1,320 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
+
+#include "us144mkii.h"
+
+/*
+ * tascam_capture_open() - Opens the PCM capture substream.
+ * @substream: The ALSA PCM substream to open.
+ *
+ * This function sets the hardware parameters for the capture substream
+ * and stores a reference to the substream in the driver's private data.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_capture_open(struct snd_pcm_substream *substream)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+
+	substream->runtime->hw = tascam_pcm_hw;
+	tascam->capture_substream = substream;
+	atomic_set(&tascam->capture_active, 0);
+
+	return 0;
+}
+
+/*
+ * tascam_capture_close() - Closes the PCM capture substream.
+ * @substream: The ALSA PCM substream to close.
+ *
+ * This function clears the reference to the capture substream in the
+ * driver's private data.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_capture_close(struct snd_pcm_substream *substream)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+
+	tascam->capture_substream = NULL;
+
+	return 0;
+}
+
+/*
+ * tascam_capture_prepare() - Prepares the PCM capture substream for use.
+ * @substream: The ALSA PCM substream to prepare.
+ *
+ * This function initializes capture-related counters and ring buffer pointers.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_capture_prepare(struct snd_pcm_substream *substream)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+
+	tascam->driver_capture_pos = 0;
+	tascam->capture_frames_processed = 0;
+	tascam->last_capture_period_pos = 0;
+	tascam->capture_ring_buffer_read_ptr = 0;
+	tascam->capture_ring_buffer_write_ptr = 0;
+
+	return 0;
+}
+
+/*
+ * tascam_capture_pointer() - Returns the current capture pointer position.
+ * @substream: The ALSA PCM substream.
+ *
+ * This function returns the current position of the capture pointer within
+ * the ALSA ring buffer, in frames.
+ *
+ * Return: The current capture pointer position in frames.
+ */
+static snd_pcm_uframes_t
+tascam_capture_pointer(struct snd_pcm_substream *substream)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	u64 pos;
+
+	if (!atomic_read(&tascam->capture_active))
+		return 0;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		pos = tascam->capture_frames_processed;
+	}
+
+	if (runtime->buffer_size == 0)
+		return 0;
+
+	return do_div(pos, runtime->buffer_size);
+}
+
+/*
+ * tascam_capture_ops - ALSA PCM operations for capture.
+ *
+ * This structure defines the callback functions for capture stream operations,
+ * including open, close, ioctl, hardware parameters, hardware free, prepare,
+ * trigger, and pointer.
+ */
+const struct snd_pcm_ops tascam_capture_ops = {
+	.open = tascam_capture_open,
+	.close = tascam_capture_close,
+	.ioctl = snd_pcm_lib_ioctl,
+	.hw_params = tascam_pcm_hw_params,
+	.hw_free = tascam_pcm_hw_free,
+	.prepare = tascam_capture_prepare,
+	.trigger = tascam_pcm_trigger,
+	.pointer = tascam_capture_pointer,
+};
+
+/*
+ * decode_tascam_capture_block() - Decodes a raw 512-byte block from the device.
+ * @src_block: Pointer to the 512-byte raw source block.
+ * @dst_block: Pointer to the destination buffer for decoded audio frames.
+ *
+ * The device sends audio data in a complex, multiplexed format. This function
+ * demultiplexes the bits from the raw block into 8 frames of 4-channel,
+ * 24-bit audio (stored in 32-bit containers).
+ */
+static void decode_tascam_capture_block(const u8 *src_block, s32 *dst_block)
+{
+	int frame, bit;
+
+	memset(dst_block, 0,
+	       FRAMES_PER_DECODE_BLOCK * DECODED_CHANNELS_PER_FRAME *
+		       DECODED_SAMPLE_SIZE);
+
+	for (frame = 0; frame < FRAMES_PER_DECODE_BLOCK; ++frame) {
+		const u8 *p_src_frame_base = src_block + frame * 64;
+		s32 *p_dst_frame = dst_block + frame * 4;
+
+		s32 ch[4] = { 0 };
+
+		for (bit = 0; bit < 24; ++bit) {
+			u8 byte1 = p_src_frame_base[bit];
+			u8 byte2 = p_src_frame_base[bit + 32];
+
+			ch[0] = (ch[0] << 1) | (byte1 & 1);
+			ch[2] = (ch[2] << 1) | ((byte1 >> 1) & 1);
+
+			ch[1] = (ch[1] << 1) | (byte2 & 1);
+			ch[3] = (ch[3] << 1) | ((byte2 >> 1) & 1);
+		}
+
+		/*
+		 * The result is a 24-bit sample. Shift left by 8 to align it to
+		 * the most significant bits of a 32-bit integer (S32_LE format).
+		 */
+		p_dst_frame[0] = ch[0] << 8;
+		p_dst_frame[1] = ch[1] << 8;
+		p_dst_frame[2] = ch[2] << 8;
+		p_dst_frame[3] = ch[3] << 8;
+	}
+}
+
+void tascam_capture_work_handler(struct work_struct *work)
+{
+	struct tascam_card *tascam =
+		container_of(work, struct tascam_card, capture_work);
+	struct snd_pcm_substream *substream = tascam->capture_substream;
+	struct snd_pcm_runtime *runtime;
+	u8 *raw_block = tascam->capture_decode_raw_block;
+	s32 *decoded_block = tascam->capture_decode_dst_block;
+	s32 *routed_block = tascam->capture_routing_buffer;
+
+	if (!substream || !substream->runtime)
+		return;
+	runtime = substream->runtime;
+
+	if (!raw_block || !decoded_block || !routed_block) {
+		dev_err(tascam->card->dev,
+			"Capture decode/routing buffers not allocated!\n");
+		return;
+	}
+
+	while (atomic_read(&tascam->capture_active)) {
+		size_t write_ptr, read_ptr, available_data;
+		bool can_process;
+
+		scoped_guard(spinlock_irqsave, &tascam->lock) {
+			write_ptr = tascam->capture_ring_buffer_write_ptr;
+			read_ptr = tascam->capture_ring_buffer_read_ptr;
+			available_data = (write_ptr >= read_ptr) ?
+						 (write_ptr - read_ptr) :
+						 (CAPTURE_RING_BUFFER_SIZE -
+						  read_ptr + write_ptr);
+			can_process =
+				(available_data >= RAW_BYTES_PER_DECODE_BLOCK);
+
+			if (can_process) {
+				size_t bytes_to_end =
+					CAPTURE_RING_BUFFER_SIZE - read_ptr;
+				if (bytes_to_end >=
+				    RAW_BYTES_PER_DECODE_BLOCK) {
+					memcpy(raw_block,
+					       tascam->capture_ring_buffer +
+						       read_ptr,
+					       RAW_BYTES_PER_DECODE_BLOCK);
+				} else {
+					memcpy(raw_block,
+					       tascam->capture_ring_buffer +
+						       read_ptr,
+					       bytes_to_end);
+					memcpy(raw_block + bytes_to_end,
+					       tascam->capture_ring_buffer,
+					       RAW_BYTES_PER_DECODE_BLOCK -
+						       bytes_to_end);
+				}
+				tascam->capture_ring_buffer_read_ptr =
+					(read_ptr +
+					 RAW_BYTES_PER_DECODE_BLOCK) %
+					CAPTURE_RING_BUFFER_SIZE;
+			}
+		}
+
+		if (!can_process)
+			break;
+
+		decode_tascam_capture_block(raw_block, decoded_block);
+		process_capture_routing_us144mkii(tascam, decoded_block,
+						  routed_block);
+
+		scoped_guard(spinlock_irqsave, &tascam->lock) {
+			if (atomic_read(&tascam->capture_active)) {
+				int f;
+
+				for (f = 0; f < FRAMES_PER_DECODE_BLOCK; ++f) {
+					u8 *dst_frame_start =
+						runtime->dma_area +
+						frames_to_bytes(
+							runtime,
+							tascam->driver_capture_pos);
+					s32 *routed_frame_start =
+						routed_block +
+						(f * NUM_CHANNELS);
+					int c;
+
+					for (c = 0; c < NUM_CHANNELS; c++) {
+						u8 *dst_channel =
+							dst_frame_start +
+							(c * BYTES_PER_SAMPLE);
+						s32 *src_channel_s32 =
+							routed_frame_start + c;
+
+						memcpy(dst_channel,
+						       ((char *)src_channel_s32) +
+							       1,
+						       3);
+					}
+
+					tascam->driver_capture_pos =
+						(tascam->driver_capture_pos +
+						 1) %
+						runtime->buffer_size;
+				}
+			}
+		}
+	}
+}
+
+void capture_urb_complete(struct urb *urb)
+{
+	struct tascam_card *tascam = urb->context;
+	int ret;
+
+	if (urb->status) {
+		if (urb->status != -ENOENT && urb->status != -ECONNRESET &&
+		    urb->status != -ESHUTDOWN && urb->status != -ENODEV &&
+		    urb->status != -EPROTO)
+			dev_err_ratelimited(tascam->card->dev,
+					    "Capture URB failed: %d\n",
+					    urb->status);
+		goto out;
+	}
+	if (!tascam || !atomic_read(&tascam->capture_active))
+		goto out;
+
+	if (urb->actual_length > 0) {
+		scoped_guard(spinlock_irqsave, &tascam->lock) {
+			size_t write_ptr = tascam->capture_ring_buffer_write_ptr;
+			size_t bytes_to_end = CAPTURE_RING_BUFFER_SIZE - write_ptr;
+
+			if (urb->actual_length > bytes_to_end) {
+				memcpy(tascam->capture_ring_buffer + write_ptr,
+				       urb->transfer_buffer, bytes_to_end);
+				memcpy(tascam->capture_ring_buffer,
+				       urb->transfer_buffer + bytes_to_end,
+				       urb->actual_length - bytes_to_end);
+			} else {
+				memcpy(tascam->capture_ring_buffer + write_ptr,
+				       urb->transfer_buffer,
+				       urb->actual_length);
+			}
+
+			tascam->capture_ring_buffer_write_ptr =
+				(write_ptr + urb->actual_length) %
+				CAPTURE_RING_BUFFER_SIZE;
+		}
+
+		schedule_work(&tascam->capture_work);
+	}
+
+	usb_get_urb(urb);
+	usb_anchor_urb(urb, &tascam->capture_anchor);
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret < 0) {
+		dev_err_ratelimited(tascam->card->dev,
+				    "Failed to resubmit capture URB: %d\n",
+				    ret);
+		usb_unanchor_urb(urb);
+		usb_put_urb(urb);
+		atomic_dec(
+			&tascam->active_urbs); /* Decrement on failed resubmission */
+		return;
+	}
+out:
+	usb_put_urb(urb);
+}
+
diff --git a/sound/usb/usx2y/us144mkii_controls.c b/sound/usb/usx2y/us144mkii_controls.c
new file mode 100644
index 000000000..81ded11e3
--- /dev/null
+++ b/sound/usb/usx2y/us144mkii_controls.c
@@ -0,0 +1,444 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
+
+#include "us144mkii.h"
+
+/*
+ * Text descriptions for playback output source options.
+ *
+ * Used by ALSA kcontrol elements to provide user-friendly names for
+ * the playback routing options (e.g., "Playback 1-2", "Playback 3-4").
+ */
+static const char *const playback_source_texts[] = { "Playback 1-2",
+						     "Playback 3-4" };
+
+/*
+ * Text descriptions for capture input source options.
+ *
+ * Used by ALSA kcontrol elements to provide user-friendly names for
+ * the capture routing options (e.g., "Analog In", "Digital In").
+ */
+static const char *const capture_source_texts[] = { "Analog In", "Digital In" };
+
+/*
+ * tascam_playback_source_info() - ALSA control info callback for playback
+ * source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @uinfo: The ALSA control element info structure to fill.
+ *
+ * This function provides information about the enumerated playback source
+ * control, including its type, count, and available items (Playback 1-2,
+ * Playback 3-4).
+ *
+ * Return: 0 on success.
+ */
+static int tascam_playback_source_info(struct snd_kcontrol *kcontrol,
+				       struct snd_ctl_elem_info *uinfo)
+{
+	return snd_ctl_enum_info(uinfo, 1, 2, playback_source_texts);
+}
+
+/*
+ * tascam_line_out_get() - ALSA control get callback for Line Outputs Source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure to fill.
+ *
+ * This function retrieves the current selection for the Line Outputs source
+ * (Playback 1-2 or Playback 3-4) from the driver's private data and populates
+ * the ALSA control element value.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_line_out_get(struct snd_kcontrol *kcontrol,
+			       struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam = snd_kcontrol_chip(kcontrol);
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		ucontrol->value.enumerated.item[0] = tascam->line_out_source;
+	}
+	return 0;
+}
+
+/*
+ * tascam_line_out_put() - ALSA control put callback for Line Outputs Source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure containing the new value.
+ *
+ * This function sets the Line Outputs source (Playback 1-2 or Playback 3-4)
+ * based on the user's selection from the ALSA control element. It validates
+ * the input and updates the driver's private data.
+ *
+ * Return: 1 if the value was changed, 0 if unchanged, or a negative error code.
+ */
+static int tascam_line_out_put(struct snd_kcontrol *kcontrol,
+			       struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam = snd_kcontrol_chip(kcontrol);
+	int changed = 0;
+
+	if (ucontrol->value.enumerated.item[0] > 1)
+		return -EINVAL;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		if (tascam->line_out_source != ucontrol->value.enumerated.item[0]) {
+			tascam->line_out_source = ucontrol->value.enumerated.item[0];
+			changed = 1;
+		}
+	}
+	return changed;
+}
+
+/*
+ * tascam_line_out_control - ALSA kcontrol definition for Line Outputs Source.
+ *
+ * This defines a new ALSA mixer control named "Line OUTPUTS Source" that allows
+ * the user to select between "Playback 1-2" and "Playback 3-4" for the analog
+ * line outputs of the device. It uses the `tascam_playback_source_info` for
+ * information and `tascam_line_out_get`/`tascam_line_out_put` for value
+ * handling.
+ */
+static const struct snd_kcontrol_new tascam_line_out_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Line Playback Source",
+	.info = tascam_playback_source_info,
+	.get = tascam_line_out_get,
+	.put = tascam_line_out_put,
+};
+
+/*
+ * tascam_digital_out_get() - ALSA control get callback for Digital Outputs
+ * Source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure to fill.
+ *
+ * This function retrieves the current selection for the Digital Outputs source
+ * (Playback 1-2 or Playback 3-4) from the driver's private data and populates
+ * the ALSA control element value.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_digital_out_get(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam = snd_kcontrol_chip(kcontrol);
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		ucontrol->value.enumerated.item[0] = tascam->digital_out_source;
+	}
+	return 0;
+}
+
+/*
+ * tascam_digital_out_put() - ALSA control put callback for Digital Outputs
+ * Source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure containing the new value.
+ *
+ * This function sets the Digital Outputs source (Playback 1-2 or Playback 3-4)
+ * based on the user's selection from the ALSA control element. It validates
+ * the input and updates the driver's private data.
+ *
+ * Return: 1 if the value was changed, 0 if unchanged, or a negative error code.
+ */
+static int tascam_digital_out_put(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam = snd_kcontrol_chip(kcontrol);
+	int changed = 0;
+
+	if (ucontrol->value.enumerated.item[0] > 1)
+		return -EINVAL;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		if (tascam->digital_out_source != ucontrol->value.enumerated.item[0]) {
+			tascam->digital_out_source = ucontrol->value.enumerated.item[0];
+			changed = 1;
+		}
+	}
+	return changed;
+}
+
+/*
+ * tascam_digital_out_control - ALSA kcontrol definition for Digital Outputs
+ * Source.
+ *
+ * This defines a new ALSA mixer control named "Digital OUTPUTS Source" that
+ * allows the user to select between "Playback 1-2" and "Playback 3-4" for the
+ * digital outputs of the device. It uses the `tascam_playback_source_info` for
+ * information and `tascam_digital_out_get`/`tascam_digital_out_put` for value
+ * handling.
+ */
+static const struct snd_kcontrol_new tascam_digital_out_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Digital Playback Source",
+	.info = tascam_playback_source_info,
+	.get = tascam_digital_out_get,
+	.put = tascam_digital_out_put,
+};
+
+/*
+ * tascam_capture_source_info() - ALSA control info callback for capture source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @uinfo: The ALSA control element info structure to fill.
+ *
+ * This function provides information about the enumerated capture source
+ * control, including its type, count, and available items (Analog In, Digital
+ * In).
+ *
+ * Return: 0 on success.
+ */
+static int tascam_capture_source_info(struct snd_kcontrol *kcontrol,
+				      struct snd_ctl_elem_info *uinfo)
+{
+	return snd_ctl_enum_info(uinfo, 1, 2, capture_source_texts);
+}
+
+/*
+ * tascam_capture_12_get() - ALSA control get callback for Capture channels 1
+ * and 2 Source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure to fill.
+ *
+ * This function retrieves the current selection for the Capture channels 1 and
+ * 2 source (Analog In or Digital In) from the driver's private data and
+ * populates the ALSA control element value.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_capture_12_get(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam = snd_kcontrol_chip(kcontrol);
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		ucontrol->value.enumerated.item[0] = tascam->capture_12_source;
+	}
+	return 0;
+}
+
+/*
+ * tascam_capture_12_put() - ALSA control put callback for Capture channels 1
+ * and 2 Source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure containing the new value.
+ *
+ * This function sets the Capture channels 1 and 2 source (Analog In or Digital
+ * In) based on the user's selection from the ALSA control element. It validates
+ * the input and updates the driver's private data.
+ *
+ * Return: 1 if the value was changed, 0 if unchanged, or a negative error code.
+ */
+static int tascam_capture_12_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam = snd_kcontrol_chip(kcontrol);
+	int changed = 0;
+
+	if (ucontrol->value.enumerated.item[0] > 1)
+		return -EINVAL;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		if (tascam->capture_12_source != ucontrol->value.enumerated.item[0]) {
+			tascam->capture_12_source = ucontrol->value.enumerated.item[0];
+			changed = 1;
+		}
+	}
+	return changed;
+}
+
+/*
+ * tascam_capture_12_control - ALSA kcontrol definition for Capture channels 1
+ * and 2 Source.
+ *
+ * This defines a new ALSA mixer control named "ch1 and ch2 Source" that allows
+ * the user to select between "Analog In" and "Digital In" for the first two
+ * capture channels of the device. It uses the `tascam_capture_source_info` for
+ * information and `tascam_capture_12_get`/`tascam_capture_12_put` for value
+ * handling.
+ */
+static const struct snd_kcontrol_new tascam_capture_12_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Ch1/2 Capture Source",
+	.info = tascam_capture_source_info,
+	.get = tascam_capture_12_get,
+	.put = tascam_capture_12_put,
+};
+
+/*
+ * tascam_capture_34_get() - ALSA control get callback for Capture channels 3
+ * and 4 Source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure to fill.
+ *
+ * This function retrieves the current selection for the Capture channels 3 and
+ * 4 source (Analog In or Digital In) from the driver's private data and
+ * populates the ALSA control element value.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_capture_34_get(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam = snd_kcontrol_chip(kcontrol);
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		ucontrol->value.enumerated.item[0] = tascam->capture_34_source;
+	}
+	return 0;
+}
+
+/*
+ * tascam_capture_34_put() - ALSA control put callback for Capture channels 3
+ * and 4 Source.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure containing the new value.
+ *
+ * This function sets the Capture channels 3 and 4 source (Analog In or Digital
+ * In) based on the user's selection from the ALSA control element. It validates
+ * the input and updates the driver's private data.
+ *
+ * Return: 1 if the value was changed, 0 if unchanged, or a negative error code.
+ */
+static int tascam_capture_34_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam = snd_kcontrol_chip(kcontrol);
+	int changed = 0;
+
+	if (ucontrol->value.enumerated.item[0] > 1)
+		return -EINVAL;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		if (tascam->capture_34_source != ucontrol->value.enumerated.item[0]) {
+			tascam->capture_34_source = ucontrol->value.enumerated.item[0];
+			changed = 1;
+		}
+	}
+	return changed;
+}
+
+/*
+ * tascam_capture_34_control - ALSA kcontrol definition for Capture channels 3
+ * and 4 Source.
+ *
+ * This defines a new ALSA mixer control named "ch3 and ch4 Source" that allows
+ * the user to select between "Analog In" and "Digital In" for the third and
+ * fourth capture channels of the device. It uses the
+ * `tascam_capture_source_info` for information and
+ * `tascam_capture_34_get`/`tascam_capture_34_put` for value handling.
+ */
+static const struct snd_kcontrol_new tascam_capture_34_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Ch3/4 Capture Source",
+	.info = tascam_capture_source_info,
+	.get = tascam_capture_34_get,
+	.put = tascam_capture_34_put,
+};
+
+/*
+ * tascam_samplerate_info() - ALSA control info callback for Sample Rate.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @uinfo: The ALSA control element info structure to fill.
+ *
+ * This function provides information about the Sample Rate control, defining
+ * it as an integer type with a minimum value of 0 and a maximum of 96000.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_samplerate_info(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 96000;
+	return 0;
+}
+
+/*
+ * tascam_samplerate_get() - ALSA control get callback for Sample Rate.
+ * @kcontrol: The ALSA kcontrol instance.
+ * @ucontrol: The ALSA control element value structure to fill.
+ *
+ * This function retrieves the current sample rate from the device via a USB
+ * control message and populates the ALSA control element value. If the rate
+ * is already known (i.e., `current_rate` is set), it returns that value
+ * directly.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+static int tascam_samplerate_get(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct tascam_card *tascam =
+		(struct tascam_card *)snd_kcontrol_chip(kcontrol);
+	int err;
+	u32 rate = 0;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		if (tascam->current_rate > 0) {
+			ucontrol->value.integer.value[0] = tascam->current_rate;
+			return 0;
+		}
+	}
+
+	u8 *buf __free(kfree) =
+		kmalloc(3, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	err = usb_control_msg(tascam->dev, usb_rcvctrlpipe(tascam->dev, 0),
+			      UAC_GET_CUR, RT_D2H_CLASS_EP,
+			      UAC_SAMPLING_FREQ_CONTROL, EP_AUDIO_IN, buf, 3,
+			      USB_CTRL_TIMEOUT_MS);
+
+	if (err >= 3)
+		rate = buf[0] | (buf[1] << 8) | (buf[2] << 16);
+
+	ucontrol->value.integer.value[0] = rate;
+	return 0;
+}
+
+/*
+ * tascam_samplerate_control - ALSA kcontrol definition for Sample Rate.
+ *
+ * This defines a new ALSA mixer control named "Sample Rate" that displays
+ * the current sample rate of the device. It is a read-only control.
+ */
+static const struct snd_kcontrol_new tascam_samplerate_control = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = "Sample Rate",
+	.info = tascam_samplerate_info,
+	.get = tascam_samplerate_get,
+	.access = SNDRV_CTL_ELEM_ACCESS_READ,
+};
+
+int tascam_create_controls(struct tascam_card *tascam)
+{
+	int err;
+
+	err = snd_ctl_add(tascam->card,
+			  snd_ctl_new1(&tascam_line_out_control, tascam));
+	if (err < 0)
+		return err;
+	err = snd_ctl_add(tascam->card,
+			  snd_ctl_new1(&tascam_digital_out_control, tascam));
+	if (err < 0)
+		return err;
+	err = snd_ctl_add(tascam->card,
+			  snd_ctl_new1(&tascam_capture_12_control, tascam));
+	if (err < 0)
+		return err;
+	err = snd_ctl_add(tascam->card,
+			  snd_ctl_new1(&tascam_capture_34_control, tascam));
+	if (err < 0)
+		return err;
+
+	err = snd_ctl_add(tascam->card,
+			  snd_ctl_new1(&tascam_samplerate_control, tascam));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
diff --git a/sound/usb/usx2y/us144mkii_midi.c b/sound/usb/usx2y/us144mkii_midi.c
new file mode 100644
index 000000000..4871797b1
--- /dev/null
+++ b/sound/usb/usx2y/us144mkii_midi.c
@@ -0,0 +1,403 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
+
+#include "us144mkii.h"
+
+/*
+ * tascam_midi_in_work_handler() - Deferred work for processing MIDI input.
+ * @work: The work_struct instance.
+ *
+ * This function runs in a thread context. It safely reads raw USB data from
+ * the kfifo, processes it by stripping protocol-specific padding bytes, and
+ * passes the clean MIDI data to the ALSA rawmidi subsystem.
+ */
+static void tascam_midi_in_work_handler(struct work_struct *work)
+{
+	struct tascam_card *tascam =
+		container_of(work, struct tascam_card, midi_in_work);
+	u8 buf[9];
+	u8 clean_buf[8];
+	unsigned int count, clean_count;
+
+	if (!tascam->midi_in_substream)
+		return;
+
+	while (kfifo_out_spinlocked(&tascam->midi_in_fifo, buf, sizeof(buf),
+				    &tascam->midi_in_lock) == sizeof(buf)) {
+		clean_count = 0;
+		for (count = 0; count < 8; ++count) {
+			if (buf[count] != 0xfd)
+				clean_buf[clean_count++] = buf[count];
+		}
+
+		if (clean_count > 0)
+			snd_rawmidi_receive(tascam->midi_in_substream,
+					    clean_buf, clean_count);
+	}
+}
+
+void tascam_midi_in_urb_complete(struct urb *urb)
+{
+	struct tascam_card *tascam = urb->context;
+	int ret;
+
+	if (!tascam)
+		goto out;
+
+	if (urb->status) {
+		if (urb->status != -ENOENT && urb->status != -ECONNRESET &&
+		    urb->status != -ESHUTDOWN && urb->status != -EPROTO) {
+			dev_err_ratelimited(tascam->card->dev,
+					    "MIDI IN URB failed: status %d\n",
+					    urb->status);
+		}
+		goto out;
+	}
+
+	if (atomic_read(&tascam->midi_in_active) &&
+	    urb->actual_length > 0) {
+		kfifo_in_spinlocked(&tascam->midi_in_fifo, urb->transfer_buffer,
+				    urb->actual_length, &tascam->midi_in_lock);
+		schedule_work(&tascam->midi_in_work);
+	}
+
+	usb_get_urb(urb);
+	usb_anchor_urb(urb, &tascam->midi_in_anchor);
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret < 0) {
+		dev_err(tascam->card->dev,
+			"Failed to resubmit MIDI IN URB: error %d\n", ret);
+		usb_unanchor_urb(urb);
+		goto out;
+	}
+
+out:
+	usb_put_urb(urb);
+}
+
+/*
+ * tascam_midi_in_open() - Opens the MIDI input substream.
+ * @substream: The ALSA rawmidi substream to open.
+ *
+ * This function stores a reference to the MIDI input substream in the
+ * driver's private data.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_midi_in_open(struct snd_rawmidi_substream *substream)
+{
+	struct tascam_card *tascam = substream->rmidi->private_data;
+
+	tascam->midi_in_substream = substream;
+	return 0;
+}
+
+/*
+ * tascam_midi_in_close() - Closes the MIDI input substream.
+ * @substream: The ALSA rawmidi substream to close.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_midi_in_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+/*
+ * tascam_midi_in_trigger() - Triggers MIDI input stream activity.
+ * @substream: The ALSA rawmidi substream.
+ * @up: Boolean indicating whether to start (1) or stop (0) the stream.
+ *
+ * This function starts or stops the MIDI input URBs based on the 'up'
+ * parameter. When starting, it resets the kfifo and submits all MIDI input
+ * URBs. When stopping, it kills all anchored MIDI input URBs and cancels the
+ * associated workqueue.
+ */
+static void tascam_midi_in_trigger(struct snd_rawmidi_substream *substream,
+				   int up)
+{
+	struct tascam_card *tascam = substream->rmidi->private_data;
+	int i, err;
+
+	if (up) {
+		if (atomic_xchg(&tascam->midi_in_active, 1) == 0) {
+			scoped_guard(spinlock_irqsave, &tascam->midi_in_lock)
+			{
+				kfifo_reset(&tascam->midi_in_fifo);
+			}
+
+			for (i = 0; i < NUM_MIDI_IN_URBS; i++) {
+				usb_get_urb(tascam->midi_in_urbs[i]);
+				usb_anchor_urb(tascam->midi_in_urbs[i],
+						       &tascam->midi_in_anchor);
+				err = usb_submit_urb(tascam->midi_in_urbs[i],
+							     GFP_KERNEL);
+				if (err < 0) {
+					dev_err(tascam->card->dev,
+						"Failed to submit MIDI IN URB %d: %d\n",
+						i, err);
+					usb_unanchor_urb(
+							tascam->midi_in_urbs[i]);
+					usb_put_urb(tascam->midi_in_urbs[i]);
+				}
+			}
+		}
+	} else {
+		if (atomic_xchg(&tascam->midi_in_active, 0) == 1) {
+			usb_kill_anchored_urbs(&tascam->midi_in_anchor);
+			cancel_work_sync(&tascam->midi_in_work);
+		}
+	}
+}
+
+/*
+ * tascam_midi_in_ops - ALSA rawmidi operations for MIDI input.
+ *
+ * This structure defines the callback functions for MIDI input stream
+ * operations, including open, close, and trigger.
+ */
+static const struct snd_rawmidi_ops tascam_midi_in_ops = {
+	.open = tascam_midi_in_open,
+	.close = tascam_midi_in_close,
+	.trigger = tascam_midi_in_trigger,
+};
+
+void tascam_midi_out_urb_complete(struct urb *urb)
+{
+	struct tascam_card *tascam = urb->context;
+	int i, urb_index = -1;
+
+	if (urb->status) {
+		if (urb->status != -ENOENT && urb->status != -ECONNRESET &&
+		    urb->status != -ESHUTDOWN) {
+			dev_err_ratelimited(tascam->card->dev,
+					    "MIDI OUT URB failed: %d\n",
+					    urb->status);
+		}
+		goto out;
+	}
+
+	if (!tascam)
+		goto out;
+
+	for (i = 0; i < NUM_MIDI_OUT_URBS; i++) {
+		if (tascam->midi_out_urbs[i] == urb) {
+			urb_index = i;
+			break;
+		}
+	}
+
+	if (urb_index < 0) {
+		dev_err_ratelimited(tascam->card->dev,
+				    "Unknown MIDI OUT URB completed!\n");
+		goto out;
+	}
+
+	scoped_guard(spinlock_irqsave, &tascam->midi_out_lock)
+	{
+		clear_bit(urb_index, &tascam->midi_out_urbs_in_flight);
+	}
+
+	if (atomic_read(&tascam->midi_out_active))
+		schedule_work(&tascam->midi_out_work);
+
+out:
+	usb_put_urb(urb);
+}
+
+/*
+ * tascam_midi_out_work_handler() - Deferred work for sending MIDI data
+ * @work: The work_struct instance.
+ *
+ * This function handles the proprietary output protocol: take the raw MIDI
+ * message bytes from the application, place them at the start of a 9-byte
+ * buffer, pad the rest with 0xFD, and add a terminator byte (0x00).
+ * This function pulls as many bytes as will fit into one packet from the
+ * ALSA buffer and sends them.
+ */
+static void tascam_midi_out_work_handler(struct work_struct *work)
+{
+	struct tascam_card *tascam =
+		container_of(work, struct tascam_card, midi_out_work);
+	struct snd_rawmidi_substream *substream = tascam->midi_out_substream;
+	int i;
+
+	if (!substream || !atomic_read(&tascam->midi_out_active))
+		return;
+
+	while (snd_rawmidi_transmit_peek(substream, (u8[]){ 0 }, 1) == 1) {
+		int urb_index;
+		struct urb *urb;
+		u8 *buf;
+		int bytes_to_send;
+
+		scoped_guard(spinlock_irqsave, &tascam->midi_out_lock) {
+			urb_index = -1;
+			for (i = 0; i < NUM_MIDI_OUT_URBS; i++) {
+				if (!test_bit(
+					    i,
+					    &tascam->midi_out_urbs_in_flight)) {
+					urb_index = i;
+					break;
+				}
+			}
+
+			if (urb_index < 0)
+				return; /* No free URBs, will be rescheduled by
+					 * completion handler
+					 */
+
+			urb = tascam->midi_out_urbs[urb_index];
+			buf = urb->transfer_buffer;
+			bytes_to_send = snd_rawmidi_transmit(substream, buf, 8);
+
+			if (bytes_to_send <= 0)
+				break; /* No more data */
+
+			if (bytes_to_send < 9)
+				memset(buf + bytes_to_send, 0xfd,
+				       9 - bytes_to_send);
+			buf[8] = 0xe0;
+
+			set_bit(urb_index, &tascam->midi_out_urbs_in_flight);
+			urb->transfer_buffer_length = 9;
+		}
+
+		usb_get_urb(urb);
+		usb_anchor_urb(urb, &tascam->midi_out_anchor);
+		if (usb_submit_urb(urb, GFP_KERNEL) < 0) {
+			dev_err_ratelimited(
+					tascam->card->dev,
+					"Failed to submit MIDI OUT URB %d\n",
+										urb_index);
+			scoped_guard(spinlock_irqsave, &tascam->midi_out_lock)
+			{
+				clear_bit(urb_index,
+					  &tascam->midi_out_urbs_in_flight);
+			}
+			usb_unanchor_urb(urb);
+			usb_put_urb(urb);
+			break; /* Stop on error */
+		}
+	}
+}
+
+/*
+ * tascam_midi_out_open() - Opens the MIDI output substream.
+ * @substream: The ALSA rawmidi substream to open.
+ *
+ * This function stores a reference to the MIDI output substream in the
+ * driver's private data and initializes the MIDI running status.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_midi_out_open(struct snd_rawmidi_substream *substream)
+{
+	struct tascam_card *tascam = substream->rmidi->private_data;
+
+	tascam->midi_out_substream = substream;
+	/* Initialize the running status state for the packet packer. */
+	tascam->midi_running_status = 0;
+	return 0;
+}
+
+/*
+ * tascam_midi_out_close() - Closes the MIDI output substream.
+ * @substream: The ALSA rawmidi substream to close.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_midi_out_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+/*
+ * tascam_midi_out_drain() - Drains the MIDI output stream.
+ * @substream: The ALSA rawmidi substream.
+ *
+ * This function cancels any pending MIDI output work and kills all
+ * anchored MIDI output URBs, ensuring all data is sent or discarded.
+ */
+static void tascam_midi_out_drain(struct snd_rawmidi_substream *substream)
+{
+	struct tascam_card *tascam = substream->rmidi->private_data;
+	bool in_flight = true;
+
+	while (in_flight) {
+		in_flight = false;
+		for (int i = 0; i < NUM_MIDI_OUT_URBS; i++) {
+			if (test_bit(i, &tascam->midi_out_urbs_in_flight)) {
+				in_flight = true;
+				break;
+			}
+		}
+		if (in_flight)
+			schedule_timeout_uninterruptible(1);
+	}
+
+	cancel_work_sync(&tascam->midi_out_work);
+	usb_kill_anchored_urbs(&tascam->midi_out_anchor);
+}
+
+/*
+ * tascam_midi_out_trigger() - Triggers MIDI output stream activity.
+ * @substream: The ALSA rawmidi substream.
+ * @up: Boolean indicating whether to start (1) or stop (0) the stream.
+ *
+ * This function starts or stops the MIDI output workqueue based on the
+ * 'up' parameter.
+ */
+static void tascam_midi_out_trigger(struct snd_rawmidi_substream *substream,
+				    int up)
+{
+	struct tascam_card *tascam = substream->rmidi->private_data;
+
+	if (up) {
+		atomic_set(&tascam->midi_out_active, 1);
+		schedule_work(&tascam->midi_out_work);
+	} else {
+		atomic_set(&tascam->midi_out_active, 0);
+	}
+}
+
+/*
+ * tascam_midi_out_ops - ALSA rawmidi operations for MIDI output.
+ *
+ * This structure defines the callback functions for MIDI output stream
+ * operations, including open, close, trigger, and drain.
+ */
+static const struct snd_rawmidi_ops tascam_midi_out_ops = {
+	.open = tascam_midi_out_open,
+	.close = tascam_midi_out_close,
+	.trigger = tascam_midi_out_trigger,
+	.drain = tascam_midi_out_drain,
+};
+
+int tascam_create_midi(struct tascam_card *tascam)
+{
+	int err;
+
+	err = snd_rawmidi_new(tascam->card, "US144MKII MIDI", 0, 1, 1,
+			      &tascam->rmidi);
+	if (err < 0)
+		return err;
+
+	strscpy(tascam->rmidi->name, "US144MKII MIDI",
+		sizeof(tascam->rmidi->name));
+	tascam->rmidi->private_data = tascam;
+
+	snd_rawmidi_set_ops(tascam->rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+			    &tascam_midi_in_ops);
+	snd_rawmidi_set_ops(tascam->rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+			    &tascam_midi_out_ops);
+
+	tascam->rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT |
+				     SNDRV_RAWMIDI_INFO_OUTPUT |
+				     SNDRV_RAWMIDI_INFO_DUPLEX;
+
+	INIT_WORK(&tascam->midi_in_work, tascam_midi_in_work_handler);
+	INIT_WORK(&tascam->midi_out_work, tascam_midi_out_work_handler);
+
+	return 0;
+}
diff --git a/sound/usb/usx2y/us144mkii_pcm.c b/sound/usb/usx2y/us144mkii_pcm.c
new file mode 100644
index 000000000..03dfb1f38
--- /dev/null
+++ b/sound/usb/usx2y/us144mkii_pcm.c
@@ -0,0 +1,370 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
+
+#include "us144mkii.h"
+
+/**
+ * fpo_init_pattern() - Generates a packet distribution pattern.
+ * @size: The number of elements in the pattern array (e.g., 8).
+ * @pattern_array: Pointer to the array to be populated.
+ * @initial_value: The base value to initialize each element with.
+ * @target_sum: The desired sum of all elements in the final array.
+ *
+ * This function initializes an array with a base value and then iteratively
+ * adjusts the elements to match a target sum, distributing the difference
+ * as evenly as possible.
+ */
+static void fpo_init_pattern(unsigned int size, unsigned int *pattern_array,
+	unsigned int initial_value, int target_sum)
+{
+	int diff, i;
+
+	if (!size)
+		return;
+
+	for (i = 0; i < size; ++i)
+		pattern_array[i] = initial_value;
+
+	diff = target_sum - (size * initial_value);
+	for (i = 0; i < abs(diff); ++i) {
+		if (diff > 0)
+			pattern_array[i]++;
+		else
+			pattern_array[i]--;
+	}
+}
+
+const struct snd_pcm_hardware tascam_pcm_hw = {
+	.info = (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
+		 SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP_VALID |
+		 SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME),
+	.formats = SNDRV_PCM_FMTBIT_S24_3LE,
+	.rates = (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |
+		  SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000),
+	.rate_min = 44100,
+	.rate_max = 96000,
+	.channels_min = NUM_CHANNELS,
+	.channels_max = NUM_CHANNELS,
+	.buffer_bytes_max = 1024 * 1024,
+	.period_bytes_min = 48 * BYTES_PER_FRAME,
+	.period_bytes_max = 1024 * BYTES_PER_FRAME,
+	.periods_min = 2,
+	.periods_max = 1024,
+};
+
+void process_playback_routing_us144mkii(struct tascam_card *tascam,
+					const u8 *src_buffer, u8 *dst_buffer,
+					size_t frames)
+{
+	size_t f;
+	const u8 *src_12, *src_34;
+	u8 *dst_line, *dst_digital;
+
+	for (f = 0; f < frames; ++f) {
+		src_12 = src_buffer + f * BYTES_PER_FRAME;
+		src_34 = src_12 + (2 * BYTES_PER_SAMPLE);
+		dst_line = dst_buffer + f * BYTES_PER_FRAME;
+		dst_digital = dst_line + (2 * BYTES_PER_SAMPLE);
+
+		/* LINE OUTPUTS (ch1/2 on device) */
+		if (tascam->line_out_source == 0) /* "ch1 and ch2" */
+			memcpy(dst_line, src_12, 2 * BYTES_PER_SAMPLE);
+		else /* "ch3 and ch4" */
+			memcpy(dst_line, src_34, 2 * BYTES_PER_SAMPLE);
+
+		/* DIGITAL OUTPUTS (ch3/4 on device) */
+		if (tascam->digital_out_source == 0) /* "ch1 and ch2" */
+			memcpy(dst_digital, src_12, 2 * BYTES_PER_SAMPLE);
+		else /* "ch3 and ch4" */
+			memcpy(dst_digital, src_34, 2 * BYTES_PER_SAMPLE);
+	}
+}
+
+void process_capture_routing_us144mkii(struct tascam_card *tascam,
+				       const s32 *decoded_block,
+				       s32 *routed_block)
+{
+	int f;
+	const s32 *src_frame;
+	s32 *dst_frame;
+
+	for (f = 0; f < FRAMES_PER_DECODE_BLOCK; f++) {
+		src_frame = decoded_block + (f * DECODED_CHANNELS_PER_FRAME);
+		dst_frame = routed_block + (f * DECODED_CHANNELS_PER_FRAME);
+
+		/* ch1 and ch2 Source */
+		if (tascam->capture_12_source == 0) { /* analog inputs */
+			dst_frame[0] = src_frame[0]; /* Analog L */
+			dst_frame[1] = src_frame[1]; /* Analog R */
+		} else { /* digital inputs */
+			dst_frame[0] = src_frame[2]; /* Digital L */
+			dst_frame[1] = src_frame[3]; /* Digital R */
+		}
+
+		/* ch3 and ch4 Source */
+		if (tascam->capture_34_source == 0) { /* analog inputs */
+			dst_frame[2] = src_frame[0]; /* Analog L (Duplicate) */
+			dst_frame[3] = src_frame[1]; /* Analog R (Duplicate) */
+		} else { /* digital inputs */
+			dst_frame[2] = src_frame[2]; /* Digital L */
+			dst_frame[3] = src_frame[3]; /* Digital R */
+		}
+	}
+}
+
+int us144mkii_configure_device_for_rate(struct tascam_card *tascam, int rate)
+{
+	struct usb_device *dev = tascam->dev;
+	u16 rate_vendor_wValue;
+	int err = 0;
+	const u8 *current_payload_src;
+
+	static const u8 payload_44100[] = { 0x44, 0xac, 0x00 };
+	static const u8 payload_48000[] = { 0x80, 0xbb, 0x00 };
+	static const u8 payload_88200[] = { 0x88, 0x58, 0x01 };
+	static const u8 payload_96000[] = { 0x00, 0x77, 0x01 };
+
+	switch (rate) {
+	case 44100:
+		current_payload_src = payload_44100;
+		rate_vendor_wValue = REG_ADDR_RATE_44100;
+		break;
+	case 48000:
+		current_payload_src = payload_48000;
+		rate_vendor_wValue = REG_ADDR_RATE_48000;
+		break;
+	case 88200:
+		current_payload_src = payload_88200;
+		rate_vendor_wValue = REG_ADDR_RATE_88200;
+		break;
+	case 96000:
+		current_payload_src = payload_96000;
+		rate_vendor_wValue = REG_ADDR_RATE_96000;
+		break;
+	default:
+		dev_err(&dev->dev,
+			"Unsupported sample rate %d for configuration\n", rate);
+		return -EINVAL;
+	}
+
+	u8 *rate_payload_buf __free(kfree) =
+		kmemdup(current_payload_src, 3, GFP_KERNEL);
+	if (!rate_payload_buf)
+		return -ENOMEM;
+
+	dev_info(&dev->dev, "Configuring device for %d Hz\n", rate);
+
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      VENDOR_REQ_MODE_CONTROL, RT_H2D_VENDOR_DEV,
+			      MODE_VAL_CONFIG, 0x0000, NULL, 0,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
+			      RT_H2D_CLASS_EP, UAC_SAMPLING_FREQ_CONTROL,
+			      EP_AUDIO_IN, rate_payload_buf, 3,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
+			      RT_H2D_CLASS_EP, UAC_SAMPLING_FREQ_CONTROL,
+			      EP_AUDIO_OUT, rate_payload_buf, 3,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      VENDOR_REQ_REGISTER_WRITE, RT_H2D_VENDOR_DEV,
+			      REG_ADDR_UNKNOWN_0D, REG_VAL_ENABLE, NULL, 0,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      VENDOR_REQ_REGISTER_WRITE, RT_H2D_VENDOR_DEV,
+			      REG_ADDR_UNKNOWN_0E, REG_VAL_ENABLE, NULL, 0,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      VENDOR_REQ_REGISTER_WRITE, RT_H2D_VENDOR_DEV,
+			      REG_ADDR_UNKNOWN_0F, REG_VAL_ENABLE, NULL, 0,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      VENDOR_REQ_REGISTER_WRITE, RT_H2D_VENDOR_DEV,
+			      rate_vendor_wValue, REG_VAL_ENABLE, NULL, 0,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      VENDOR_REQ_REGISTER_WRITE, RT_H2D_VENDOR_DEV,
+			      REG_ADDR_UNKNOWN_11, REG_VAL_ENABLE, NULL, 0,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			      VENDOR_REQ_MODE_CONTROL, RT_H2D_VENDOR_DEV,
+			      MODE_VAL_STREAM_START, 0x0000, NULL, 0,
+			      USB_CTRL_TIMEOUT_MS);
+	if (err < 0)
+		goto fail;
+	return 0;
+
+fail:
+	dev_err(&dev->dev,
+		"Device configuration failed at rate %d with error %d\n", rate,
+		err);
+	return err;
+}
+
+int tascam_pcm_hw_params(struct snd_pcm_substream *substream,
+					 struct snd_pcm_hw_params *params)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+	int err;
+	unsigned int rate = params_rate(params);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		tascam->fpo.sample_rate_khz = rate / 1000;
+		tascam->fpo.base_feedback_value = tascam->fpo.sample_rate_khz;
+		tascam->fpo.feedback_offset = 2;
+		tascam->fpo.current_index = 0;
+		tascam->fpo.previous_index = 0;
+		tascam->fpo.sync_locked = false;
+
+		unsigned int initial_value = tascam->fpo.sample_rate_khz / 8;
+
+		for (int i = 0; i < 5; i++) {
+			int target_sum = tascam->fpo.sample_rate_khz -
+					 tascam->fpo.feedback_offset + i;
+			fpo_init_pattern(8, tascam->fpo.full_frame_patterns[i],
+					       initial_value, target_sum);
+		}
+	}
+
+	if (tascam->current_rate != rate) {
+		err = us144mkii_configure_device_for_rate(tascam, rate);
+		if (err < 0) {
+			tascam->current_rate = 0;
+			return err;
+		}
+		tascam->current_rate = rate;
+	}
+
+	return 0;
+}
+
+int tascam_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	return 0;
+}
+
+int tascam_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+	int err = 0;
+	int i;
+	bool do_start = false;
+	bool do_stop = false;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		switch (cmd) {
+		case SNDRV_PCM_TRIGGER_START:
+		case SNDRV_PCM_TRIGGER_RESUME:
+			if (!atomic_read(&tascam->playback_active)) {
+				atomic_set(&tascam->playback_active, 1);
+				atomic_set(&tascam->capture_active, 1);
+				do_start = true;
+			}
+			break;
+		case SNDRV_PCM_TRIGGER_STOP:
+		case SNDRV_PCM_TRIGGER_SUSPEND:
+		case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+			if (atomic_read(&tascam->playback_active)) {
+				atomic_set(&tascam->playback_active, 0);
+				atomic_set(&tascam->capture_active, 0);
+				do_stop = true;
+			}
+			break;
+		default:
+			err = -EINVAL;
+			break;
+		}
+	}
+
+	if (do_start) {
+		if (atomic_read(&tascam->active_urbs) > 0) {
+			dev_warn(tascam->card->dev,
+				 "Cannot start, URBs still active.\n");
+			return -EAGAIN;
+		}
+
+		for (i = 0; i < NUM_FEEDBACK_URBS; i++) {
+			usb_get_urb(tascam->feedback_urbs[i]);
+			usb_anchor_urb(tascam->feedback_urbs[i],
+					       &tascam->feedback_anchor);
+			err = usb_submit_urb(tascam->feedback_urbs[i],
+						     GFP_ATOMIC);
+			if (err < 0) {
+				usb_unanchor_urb(tascam->feedback_urbs[i]);
+				usb_put_urb(tascam->feedback_urbs[i]);
+				atomic_dec(&tascam->active_urbs);
+				goto start_rollback;
+			}
+			atomic_inc(&tascam->active_urbs);
+		}
+		for (i = 0; i < NUM_PLAYBACK_URBS; i++) {
+			usb_get_urb(tascam->playback_urbs[i]);
+			usb_anchor_urb(tascam->playback_urbs[i],
+					       &tascam->playback_anchor);
+			err = usb_submit_urb(tascam->playback_urbs[i],
+						     GFP_ATOMIC);
+			if (err < 0) {
+				usb_unanchor_urb(tascam->playback_urbs[i]);
+				usb_put_urb(tascam->playback_urbs[i]);
+				atomic_dec(&tascam->active_urbs);
+				goto start_rollback;
+			}
+			atomic_inc(&tascam->active_urbs);
+		}
+		for (i = 0; i < NUM_CAPTURE_URBS; i++) {
+			usb_get_urb(tascam->capture_urbs[i]);
+			usb_anchor_urb(tascam->capture_urbs[i],
+				       &tascam->capture_anchor);
+			err = usb_submit_urb(tascam->capture_urbs[i],
+					     GFP_ATOMIC);
+			if (err < 0) {
+				usb_unanchor_urb(tascam->capture_urbs[i]);
+				usb_put_urb(tascam->capture_urbs[i]);
+				atomic_dec(&tascam->active_urbs);
+				goto start_rollback;
+			}
+			atomic_inc(&tascam->active_urbs);
+		}
+
+		return 0;
+start_rollback:
+		dev_err(tascam->card->dev,
+			"Failed to submit URBs to start stream: %d\n", err);
+		do_stop = true;
+	}
+
+	if (do_stop)
+		schedule_work(&tascam->stop_work);
+
+	return err;
+}
+
+int tascam_init_pcm(struct snd_pcm *pcm)
+{
+	struct tascam_card *tascam = pcm->private_data;
+
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &tascam_playback_ops);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &tascam_capture_ops);
+
+	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
+				       tascam->dev->dev.parent, 64 * 1024,
+				       tascam_pcm_hw.buffer_bytes_max);
+
+	return 0;
+}
diff --git a/sound/usb/usx2y/us144mkii_pcm.h b/sound/usb/usx2y/us144mkii_pcm.h
new file mode 100644
index 000000000..a13067840
--- /dev/null
+++ b/sound/usb/usx2y/us144mkii_pcm.h
@@ -0,0 +1,165 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
+
+#ifndef __US144MKII_PCM_H
+#define __US144MKII_PCM_H
+
+#include "us144mkii.h"
+
+/**
+ * var tascam_pcm_hw - Hardware capabilities for TASCAM US-144MKII PCM.
+ *
+ * Defines the supported PCM formats, rates, channels, and buffer/period sizes
+ * for the TASCAM US-144MKII audio interface.
+ */
+extern const struct snd_pcm_hardware tascam_pcm_hw;
+
+/**
+ * var tascam_playback_ops - ALSA PCM operations for playback.
+ *
+ * This structure defines the callback functions for playback stream operations.
+ */
+extern const struct snd_pcm_ops tascam_playback_ops;
+
+/**
+ * var tascam_capture_ops - ALSA PCM operations for capture.
+ *
+ * This structure defines the callback functions for capture stream operations.
+ */
+extern const struct snd_pcm_ops tascam_capture_ops;
+
+/**
+ * playback_urb_complete() - Completion handler for playback isochronous URBs.
+ * @urb: the completed URB
+ *
+ * This function runs in interrupt context. It calculates the number of bytes
+ * to send in the next set of packets based on the feedback-driven clock,
+ * copies the audio data from the ALSA ring buffer, and resubmits the URB.
+ */
+void playback_urb_complete(struct urb *urb);
+
+/**
+ * feedback_urb_complete() - Completion handler for feedback isochronous URBs.
+ * @urb: the completed URB
+ *
+ * This is the master clock for the driver. It runs in interrupt context.
+ * It reads the feedback value from the device, which indicates how many
+ * samples the device has consumed. This information is used to adjust the
+ * playback rate and to advance the capture stream pointer, keeping both
+ * streams in sync. It then calls snd_pcm_period_elapsed if necessary and
+ * resubmits itself.
+ */
+void feedback_urb_complete(struct urb *urb);
+
+/**
+ * capture_urb_complete() - Completion handler for capture bulk URBs.
+ * @urb: the completed URB
+ *
+ * This function runs in interrupt context. It copies the received raw data
+ * into an intermediate ring buffer and then schedules the workqueue to process
+ * it. It then resubmits the URB to receive more data.
+ */
+void capture_urb_complete(struct urb *urb);
+
+/**
+ * tascam_stop_pcm_work_handler() - Work handler to stop PCM streams.
+ * @work: Pointer to the work_struct.
+ *
+ * This function is scheduled to stop PCM streams (playback and capture)
+ * from a workqueue context, avoiding blocking operations in interrupt context.
+ */
+void tascam_stop_pcm_work_handler(struct work_struct *work);
+
+/**
+ * tascam_init_pcm() - Initializes the ALSA PCM device.
+ * @pcm: Pointer to the ALSA PCM device to initialize.
+ *
+ * This function sets up the PCM operations, adds ALSA controls for routing
+ * and sample rate, and preallocates pages for the PCM buffer.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int tascam_init_pcm(struct snd_pcm *pcm);
+
+/**
+ * us144mkii_configure_device_for_rate() - Set sample rate via USB control msgs
+ * @tascam: the tascam_card instance
+ * @rate: the target sample rate (e.g., 44100, 96000)
+ *
+ * This function sends a sequence of vendor-specific and UAC control messages
+ * to configure the device hardware for the specified sample rate.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int us144mkii_configure_device_for_rate(struct tascam_card *tascam, int rate);
+
+/**
+ * process_playback_routing_us144mkii() - Apply playback routing matrix
+ * @tascam: The driver instance.
+ * @src_buffer: Buffer containing 4 channels of S24_3LE audio from ALSA.
+ * @dst_buffer: Buffer to be filled for the USB device.
+ * @frames: Number of frames to process.
+ */
+void process_playback_routing_us144mkii(struct tascam_card *tascam,
+					const u8 *src_buffer, u8 *dst_buffer,
+					size_t frames);
+
+/**
+ * process_capture_routing_us144mkii() - Apply capture routing matrix
+ * @tascam: The driver instance.
+ * @decoded_block: Buffer containing 4 channels of S32LE decoded audio.
+ * @routed_block: Buffer to be filled for ALSA.
+ */
+void process_capture_routing_us144mkii(struct tascam_card *tascam,
+				       const s32 *decoded_block,
+				       s32 *routed_block);
+
+/**
+ * tascam_pcm_hw_params() - Configures hardware parameters for PCM streams.
+ * @substream: The ALSA PCM substream.
+ * @params: The hardware parameters to apply.
+ *
+ * This function allocates pages for the PCM buffer and, for playback streams,
+ * selects the appropriate feedback patterns based on the requested sample rate.
+ * It also configures the device hardware for the selected sample rate if it
+ * has changed.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int tascam_pcm_hw_params(struct snd_pcm_substream *substream,
+			 struct snd_pcm_hw_params *params);
+
+/**
+ * tascam_pcm_hw_free() - Frees hardware parameters for PCM streams.
+ * @substream: The ALSA PCM substream.
+ *
+ * This function is a stub for freeing hardware-related resources.
+ *
+ * Return: 0 on success.
+ */
+int tascam_pcm_hw_free(struct snd_pcm_substream *substream);
+
+/**
+ * tascam_pcm_trigger() - Triggers the start or stop of PCM streams.
+ * @substream: The ALSA PCM substream.
+ * @cmd: The trigger command (e.g., SNDRV_PCM_TRIGGER_START).
+ *
+ * This function handles starting and stopping of playback and capture streams
+ * by submitting or killing the associated URBs.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+int tascam_pcm_trigger(struct snd_pcm_substream *substream, int cmd);
+
+/**
+ * tascam_capture_work_handler() - Deferred work for processing capture data.
+ * @work: the work_struct instance
+ *
+ * This function runs in a kernel thread context, not an IRQ context. It reads
+ * raw data from the capture ring buffer, decodes it, applies routing, and
+ * copies the final audio data into the ALSA capture ring buffer. This offloads
+ * the CPU-intensive decoding from the time-sensitive URB completion handlers.
+ */
+void tascam_capture_work_handler(struct work_struct *work);
+
+#endif /* __US144MKII_PCM_H */
diff --git a/sound/usb/usx2y/us144mkii_playback.c b/sound/usb/usx2y/us144mkii_playback.c
new file mode 100644
index 000000000..7efaca0a6
--- /dev/null
+++ b/sound/usb/usx2y/us144mkii_playback.c
@@ -0,0 +1,456 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
+
+#include "us144mkii.h"
+
+/*
+ * tascam_playback_open() - Opens the PCM playback substream.
+ * @substream: The ALSA PCM substream to open.
+ *
+ * This function sets the hardware parameters for the playback substream
+ * and stores a reference to the substream in the driver's private data.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_playback_open(struct snd_pcm_substream *substream)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+
+	substream->runtime->hw = tascam_pcm_hw;
+	tascam->playback_substream = substream;
+	atomic_set(&tascam->playback_active, 0);
+
+	return 0;
+}
+
+/*
+ * tascam_playback_close() - Closes the PCM playback substream.
+ * @substream: The ALSA PCM substream to close.
+ *
+ * This function clears the reference to the playback substream in the
+ * driver's private data.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_playback_close(struct snd_pcm_substream *substream)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+
+	tascam->playback_substream = NULL;
+
+	return 0;
+}
+
+/*
+ * tascam_playback_prepare() - Prepares the PCM playback substream for use.
+ * @substream: The ALSA PCM substream to prepare.
+ *
+ * This function initializes playback-related counters and flags, and configures
+ * the playback URBs with appropriate packet sizes based on the nominal frame
+ * rate.
+ *
+ * Return: 0 on success.
+ */
+static int tascam_playback_prepare(struct snd_pcm_substream *substream)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	int i, u;
+	size_t nominal_frames_per_packet, nominal_bytes_per_packet;
+	size_t total_bytes_in_urb;
+
+	tascam->driver_playback_pos = 0;
+	tascam->playback_frames_consumed = 0;
+	tascam->last_period_pos = 0;
+	tascam->feedback_pattern_in_idx = 0;
+	tascam->feedback_pattern_out_idx = 0;
+	tascam->feedback_synced = false;
+	tascam->feedback_consecutive_errors = 0;
+	tascam->feedback_urb_skip_count = NUM_FEEDBACK_URBS;
+
+	nominal_frames_per_packet = runtime->rate / 8000;
+	for (i = 0; i < FEEDBACK_ACCUMULATOR_SIZE; i++)
+		tascam->feedback_accumulator_pattern[i] =
+			nominal_frames_per_packet;
+
+	for (i = 0; i < NUM_FEEDBACK_URBS; i++) {
+		struct urb *f_urb = tascam->feedback_urbs[i];
+		int j;
+
+		f_urb->number_of_packets = FEEDBACK_URB_PACKETS;
+		f_urb->transfer_buffer_length =
+			FEEDBACK_URB_PACKETS * FEEDBACK_PACKET_SIZE;
+		for (j = 0; j < FEEDBACK_URB_PACKETS; j++) {
+			f_urb->iso_frame_desc[j].offset =
+				j * FEEDBACK_PACKET_SIZE;
+			f_urb->iso_frame_desc[j].length = FEEDBACK_PACKET_SIZE;
+		}
+	}
+
+	nominal_bytes_per_packet = nominal_frames_per_packet * BYTES_PER_FRAME;
+	total_bytes_in_urb = nominal_bytes_per_packet * PLAYBACK_URB_PACKETS;
+
+	for (u = 0; u < NUM_PLAYBACK_URBS; u++) {
+		struct urb *urb = tascam->playback_urbs[u];
+
+		memset(urb->transfer_buffer, 0,
+		       tascam->playback_urb_alloc_size);
+		urb->transfer_buffer_length = total_bytes_in_urb;
+		urb->number_of_packets = PLAYBACK_URB_PACKETS;
+		for (i = 0; i < PLAYBACK_URB_PACKETS; i++) {
+			urb->iso_frame_desc[i].offset =
+				i * nominal_bytes_per_packet;
+			urb->iso_frame_desc[i].length =
+				nominal_bytes_per_packet;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * tascam_playback_pointer() - Returns the current playback pointer position.
+ * @substream: The ALSA PCM substream.
+ *
+ * This function returns the current position of the playback pointer within
+ * the ALSA ring buffer, in frames.
+ *
+ * Return: The current playback pointer position in frames.
+ */
+static snd_pcm_uframes_t
+tascam_playback_pointer(struct snd_pcm_substream *substream)
+{
+	struct tascam_card *tascam = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	u64 pos;
+
+	if (!atomic_read(&tascam->playback_active))
+		return 0;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		pos = tascam->playback_frames_consumed;
+	}
+
+	if (runtime->buffer_size == 0)
+		return 0;
+
+	return do_div(pos, runtime->buffer_size);
+}
+
+/*
+ * tascam_playback_ops - ALSA PCM operations for playback.
+ *
+ * This structure defines the callback functions for playback stream operations,
+ * including open, close, ioctl, hardware parameters, hardware free, prepare,
+ * trigger, and pointer.
+ */
+const struct snd_pcm_ops tascam_playback_ops = {
+	.open = tascam_playback_open,
+	.close = tascam_playback_close,
+	.ioctl = snd_pcm_lib_ioctl,
+	.hw_params = tascam_pcm_hw_params,
+	.hw_free = tascam_pcm_hw_free,
+	.prepare = tascam_playback_prepare,
+	.trigger = tascam_pcm_trigger,
+	.pointer = tascam_playback_pointer,
+};
+
+void playback_urb_complete(struct urb *urb)
+{
+	struct tascam_card *tascam = urb->context;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	size_t total_bytes_for_urb = 0;
+	snd_pcm_uframes_t offset_frames;
+	snd_pcm_uframes_t frames_to_copy;
+	int ret, i;
+
+	if (urb->status) {
+		if (urb->status != -ENOENT && urb->status != -ECONNRESET &&
+		    urb->status != -ESHUTDOWN && urb->status != -ENODEV)
+			dev_err_ratelimited(tascam->card->dev,
+					    "Playback URB failed: %d\n",
+					    urb->status);
+		goto out;
+	}
+	if (!tascam || !atomic_read(&tascam->playback_active))
+		goto out;
+
+	substream = tascam->playback_substream;
+	if (!substream || !substream->runtime)
+		goto out;
+	runtime = substream->runtime;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		for (i = 0; i < urb->number_of_packets; i++) {
+			unsigned int frames_for_packet;
+			size_t bytes_for_packet;
+
+			if (tascam->feedback_synced) {
+				frames_for_packet =
+					tascam->feedback_accumulator_pattern
+						[tascam->feedback_pattern_out_idx];
+				tascam->feedback_pattern_out_idx =
+					(tascam->feedback_pattern_out_idx + 1) %
+					FEEDBACK_ACCUMULATOR_SIZE;
+			} else {
+				frames_for_packet = runtime->rate / 8000;
+			}
+			bytes_for_packet = frames_for_packet * BYTES_PER_FRAME;
+
+			urb->iso_frame_desc[i].offset = total_bytes_for_urb;
+			urb->iso_frame_desc[i].length = bytes_for_packet;
+			total_bytes_for_urb += bytes_for_packet;
+		}
+		urb->transfer_buffer_length = total_bytes_for_urb;
+
+		offset_frames = tascam->driver_playback_pos;
+		frames_to_copy = bytes_to_frames(runtime, total_bytes_for_urb);
+		tascam->driver_playback_pos =
+			(offset_frames + frames_to_copy) % runtime->buffer_size;
+	}
+
+	if (total_bytes_for_urb > 0) {
+		u8 *dst_buf = urb->transfer_buffer;
+
+		/* Handle ring buffer wrap-around */
+		if (offset_frames + frames_to_copy > runtime->buffer_size) {
+			size_t first_chunk_bytes = frames_to_bytes(
+				runtime, runtime->buffer_size - offset_frames);
+			size_t second_chunk_bytes =
+				total_bytes_for_urb - first_chunk_bytes;
+
+			memcpy(dst_buf,
+			       runtime->dma_area +
+				       frames_to_bytes(runtime, offset_frames),
+			       first_chunk_bytes);
+			memcpy(dst_buf + first_chunk_bytes, runtime->dma_area,
+			       second_chunk_bytes);
+		} else {
+			memcpy(dst_buf,
+			       runtime->dma_area +
+				       frames_to_bytes(runtime, offset_frames),
+			       total_bytes_for_urb);
+		}
+
+		process_playback_routing_us144mkii(tascam, dst_buf, dst_buf,
+						   frames_to_copy);
+	}
+
+	urb->dev = tascam->dev;
+	usb_get_urb(urb);
+	usb_anchor_urb(urb, &tascam->playback_anchor);
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret < 0) {
+		dev_err_ratelimited(tascam->card->dev,
+				    "Failed to resubmit playback URB: %d\n",
+				    ret);
+		usb_unanchor_urb(urb);
+		usb_put_urb(urb);
+		atomic_dec(
+			&tascam->active_urbs); /* Decrement on failed resubmission */
+	}
+out:
+	usb_put_urb(urb);
+}
+
+void feedback_urb_complete(struct urb *urb)
+{
+	struct tascam_card *tascam = urb->context;
+	struct snd_pcm_substream *playback_ss, *capture_ss;
+	struct snd_pcm_runtime *playback_rt, *capture_rt;
+	u64 total_frames_in_urb = 0;
+	int ret, p;
+	unsigned int old_in_idx, new_in_idx;
+	bool playback_period_elapsed = false;
+	bool capture_period_elapsed = false;
+
+	if (urb->status) {
+		if (urb->status != -ENOENT && urb->status != -ECONNRESET &&
+		    urb->status != -ESHUTDOWN && urb->status != -ENODEV) {
+			dev_err_ratelimited(tascam->card->dev,
+					    "Feedback URB failed: %d\n",
+					    urb->status);
+			atomic_dec(
+				&tascam->active_urbs); /* Decrement on failed resubmission */
+		}
+		goto out;
+	}
+	if (!tascam || !atomic_read(&tascam->playback_active))
+		goto out;
+
+	playback_ss = tascam->playback_substream;
+	if (!playback_ss || !playback_ss->runtime)
+		goto out;
+	playback_rt = playback_ss->runtime;
+
+	capture_ss = tascam->capture_substream;
+	capture_rt = capture_ss ? capture_ss->runtime : NULL;
+
+	scoped_guard(spinlock_irqsave, &tascam->lock) {
+		if (tascam->feedback_urb_skip_count > 0) {
+			tascam->feedback_urb_skip_count--;
+			break;
+		}
+
+		old_in_idx = tascam->feedback_pattern_in_idx;
+
+		for (p = 0; p < urb->number_of_packets; p++) {
+			u8 feedback_value = 0;
+			const unsigned int *pattern;
+			bool packet_ok =
+				(urb->iso_frame_desc[p].status == 0 &&
+				 urb->iso_frame_desc[p].actual_length >= 1);
+
+			if (packet_ok)
+				feedback_value =
+					*((u8 *)urb->transfer_buffer +
+					  urb->iso_frame_desc[p].offset);
+
+			if (packet_ok) {
+				int delta = feedback_value -
+						    tascam->fpo.base_feedback_value +
+						    tascam->fpo.feedback_offset;
+				int pattern_idx;
+
+				if (delta < 0) {
+					pattern_idx =
+						0; // Clamp to the lowest pattern
+				} else if (delta >= 5) {
+					pattern_idx =
+						4; // Clamp to the highest pattern
+				} else {
+					pattern_idx = delta;
+				}
+
+				pattern =
+					tascam->fpo
+						.full_frame_patterns[pattern_idx];
+				tascam->feedback_consecutive_errors = 0;
+				int i;
+
+				for (i = 0; i < 8; i++) {
+					unsigned int in_idx =
+						(tascam->feedback_pattern_in_idx +
+						 i) %
+						FEEDBACK_ACCUMULATOR_SIZE;
+
+					tascam->feedback_accumulator_pattern
+						[in_idx] = pattern[i];
+					total_frames_in_urb += pattern[i];
+				}
+			} else {
+				unsigned int nominal_frames =
+					playback_rt->rate / 8000;
+				int i;
+
+				if (tascam->feedback_synced) {
+					tascam->feedback_consecutive_errors++;
+					if (tascam->feedback_consecutive_errors >
+					    FEEDBACK_SYNC_LOSS_THRESHOLD) {
+						dev_err(tascam->card->dev,
+							"Fatal: Feedback sync lost. Stopping stream.\n");
+						schedule_work(
+								&tascam->stop_pcm_work);
+						tascam->feedback_synced = false;
+						break;
+					}
+				}
+				for (i = 0; i < 8; i++) {
+					unsigned int in_idx =
+						(tascam->feedback_pattern_in_idx +
+						 i) %
+						FEEDBACK_ACCUMULATOR_SIZE;
+
+					tascam->feedback_accumulator_pattern
+						[in_idx] = nominal_frames;
+					total_frames_in_urb += nominal_frames;
+				}
+			}
+			tascam->feedback_pattern_in_idx =
+				(tascam->feedback_pattern_in_idx + 8) %
+				FEEDBACK_ACCUMULATOR_SIZE;
+		}
+
+		new_in_idx = tascam->feedback_pattern_in_idx;
+
+		if (!tascam->feedback_synced) {
+			unsigned int out_idx = tascam->feedback_pattern_out_idx;
+			bool is_ahead = (new_in_idx - out_idx) %
+						FEEDBACK_ACCUMULATOR_SIZE <
+					(FEEDBACK_ACCUMULATOR_SIZE / 2);
+			bool was_behind = (old_in_idx - out_idx) %
+						FEEDBACK_ACCUMULATOR_SIZE >=
+					(FEEDBACK_ACCUMULATOR_SIZE / 2);
+
+			if (is_ahead && was_behind) {
+				dev_dbg(tascam->card->dev,
+					"Sync Acquired! (in: %u, out: %u)\n",
+					new_in_idx, out_idx);
+				tascam->feedback_synced = true;
+				tascam->feedback_consecutive_errors = 0;
+			}
+		}
+
+		if (total_frames_in_urb > 0) {
+			tascam->playback_frames_consumed += total_frames_in_urb;
+			if (atomic_read(&tascam->capture_active))
+				tascam->capture_frames_processed +=
+					total_frames_in_urb;
+		}
+
+		if (playback_rt->period_size > 0) {
+			u64 current_period =
+				div_u64(tascam->playback_frames_consumed,
+						playback_rt->period_size);
+
+			if (current_period > tascam->last_period_pos) {
+				tascam->last_period_pos = current_period;
+				playback_period_elapsed = true;
+			}
+		}
+
+		if (atomic_read(&tascam->capture_active) && capture_rt &&
+		    capture_rt->period_size > 0) {
+			u64 current_capture_period =
+				div_u64(tascam->capture_frames_processed,
+						capture_rt->period_size);
+
+			if (current_capture_period >
+			    tascam->last_capture_period_pos) {
+				tascam->last_capture_period_pos =
+					current_capture_period;
+				capture_period_elapsed = true;
+			}
+		}
+	}
+	if (playback_period_elapsed)
+		snd_pcm_period_elapsed(playback_ss);
+	if (capture_period_elapsed)
+		snd_pcm_period_elapsed(capture_ss);
+
+	urb->dev = tascam->dev;
+	usb_get_urb(urb);
+	usb_anchor_urb(urb, &tascam->feedback_anchor);
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret < 0) {
+		dev_err_ratelimited(tascam->card->dev,
+				    "Failed to resubmit feedback URB: %d\n",
+				    ret);
+		usb_unanchor_urb(urb);
+		usb_put_urb(urb);
+	}
+out:
+	usb_put_urb(urb);
+}
+
+void tascam_stop_pcm_work_handler(struct work_struct *work)
+{
+	struct tascam_card *tascam =
+		container_of(work, struct tascam_card, stop_pcm_work);
+
+	if (tascam->playback_substream)
+		snd_pcm_stop(tascam->playback_substream, SNDRV_PCM_STATE_XRUN);
+	if (tascam->capture_substream)
+		snd_pcm_stop(tascam->capture_substream, SNDRV_PCM_STATE_XRUN);
+}
diff --git a/sound/usb/usx2y/usX2Yhwdep.c b/sound/usb/usx2y/usX2Yhwdep.c
new file mode 100644
index 000000000..7f153a2fc
--- /dev/null
+++ b/sound/usb/usx2y/usX2Yhwdep.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Tascam US-X2Y USB soundcards
+ *
+ * FPGA Loader + ALSA Startup
+ *
+ * Copyright (c) 2003 by Karsten Wiese <annabellesgarden@yahoo.de>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <sound/core.h>
+#include <sound/memalloc.h>
+#include <sound/pcm.h>
+#include <sound/hwdep.h>
+#include "usx2y.h"
+#include "usbusx2y.h"
+#include "usX2Yhwdep.h"
+
+static vm_fault_t snd_us428ctls_vm_fault(struct vm_fault *vmf)
+{
+	unsigned long offset;
+	struct page *page;
+	void *vaddr;
+
+	offset = vmf->pgoff << PAGE_SHIFT;
+	if (offset >= US428_SHAREDMEM_PAGES)
+		return VM_FAULT_SIGBUS;
+	vaddr = (char *)((struct usx2ydev *)vmf->vma->vm_private_data)->us428ctls_sharedmem + offset;
+	page = virt_to_page(vaddr);
+	get_page(page);
+	vmf->page = page;
+
+	return 0;
+}
+
+static const struct vm_operations_struct us428ctls_vm_ops = {
+	.fault = snd_us428ctls_vm_fault,
+};
+
+static int snd_us428ctls_mmap(struct snd_hwdep *hw, struct file *filp, struct vm_area_struct *area)
+{
+	unsigned long	size = (unsigned long)(area->vm_end - area->vm_start);
+	struct usx2ydev	*us428 = hw->private_data;
+
+	// FIXME this hwdep interface is used twice: fpga download and mmap for controlling Lights etc. Maybe better using 2 hwdep devs?
+	// so as long as the device isn't fully initialised yet we return -EBUSY here.
+	if (!(us428->chip_status & USX2Y_STAT_CHIP_INIT))
+		return -EBUSY;
+
+	/* if userspace tries to mmap beyond end of our buffer, fail */
+	if (size > US428_SHAREDMEM_PAGES) {
+		dev_dbg(hw->card->dev, "%s: mmap size %lu > %lu\n", __func__,
+			size, (unsigned long)US428_SHAREDMEM_PAGES);
+		return -EINVAL;
+	}
+
+	area->vm_ops = &us428ctls_vm_ops;
+	vm_flags_set(area, VM_DONTEXPAND | VM_DONTDUMP);
+	area->vm_private_data = hw->private_data;
+	return 0;
+}
+
+static __poll_t snd_us428ctls_poll(struct snd_hwdep *hw, struct file *file, poll_table *wait)
+{
+	__poll_t	mask = 0;
+	struct usx2ydev	*us428 = hw->private_data;
+	struct us428ctls_sharedmem *shm = us428->us428ctls_sharedmem;
+
+	if (us428->chip_status & USX2Y_STAT_CHIP_HUP)
+		return EPOLLHUP;
+
+	poll_wait(file, &us428->us428ctls_wait_queue_head, wait);
+
+	if (shm && shm->ctl_snapshot_last != shm->ctl_snapshot_red)
+		mask |= EPOLLIN;
+
+	return mask;
+}
+
+
+static int snd_usx2y_hwdep_dsp_status(struct snd_hwdep *hw,
+				      struct snd_hwdep_dsp_status *info)
+{
+	static const char * const type_ids[USX2Y_TYPE_NUMS] = {
+		[USX2Y_TYPE_122] = "us122",
+		[USX2Y_TYPE_224] = "us224",
+		[USX2Y_TYPE_428] = "us428",
+	};
+	struct usx2ydev	*us428 = hw->private_data;
+	int id = -1;
+
+	switch (le16_to_cpu(us428->dev->descriptor.idProduct)) {
+	case USB_ID_US122:
+		id = USX2Y_TYPE_122;
+		break;
+	case USB_ID_US224:
+		id = USX2Y_TYPE_224;
+		break;
+	case USB_ID_US428:
+		id = USX2Y_TYPE_428;
+		break;
+	}
+	if (id < 0)
+		return -ENODEV;
+	strscpy(info->id, type_ids[id]);
+	info->num_dsps = 2;		// 0: Prepad Data, 1: FPGA Code
+	if (us428->chip_status & USX2Y_STAT_CHIP_INIT)
+		info->chip_ready = 1;
+	info->version = USX2Y_DRIVER_VERSION;
+	return 0;
+}
+
+static int usx2y_create_usbmidi(struct snd_card *card)
+{
+	static const struct snd_usb_midi_endpoint_info quirk_data_1 = {
+		.out_ep = 0x06,
+		.in_ep = 0x06,
+		.out_cables =	0x001,
+		.in_cables =	0x001
+	};
+	static const struct snd_usb_audio_quirk quirk_1 = {
+		.vendor_name =	"TASCAM",
+		.product_name =	NAME_ALLCAPS,
+		.ifnum =	0,
+		.type = QUIRK_MIDI_FIXED_ENDPOINT,
+		.data = &quirk_data_1
+	};
+	static const struct snd_usb_midi_endpoint_info quirk_data_2 = {
+		.out_ep = 0x06,
+		.in_ep = 0x06,
+		.out_cables =	0x003,
+		.in_cables =	0x003
+	};
+	static const struct snd_usb_audio_quirk quirk_2 = {
+		.vendor_name =	"TASCAM",
+		.product_name =	"US428",
+		.ifnum =	0,
+		.type = QUIRK_MIDI_FIXED_ENDPOINT,
+		.data = &quirk_data_2
+	};
+	struct usb_device *dev = usx2y(card)->dev;
+	struct usb_interface *iface = usb_ifnum_to_if(dev, 0);
+	const struct snd_usb_audio_quirk *quirk =
+		le16_to_cpu(dev->descriptor.idProduct) == USB_ID_US428 ?
+		&quirk_2 : &quirk_1;
+
+	return snd_usbmidi_create(card, iface, &usx2y(card)->midi_list, quirk);
+}
+
+static int usx2y_create_alsa_devices(struct snd_card *card)
+{
+	int err;
+
+	err = usx2y_create_usbmidi(card);
+	if (err < 0) {
+		dev_err(card->dev, "%s: usx2y_create_usbmidi error %i\n",
+			__func__, err);
+		return err;
+	}
+	err = usx2y_audio_create(card);
+	if (err < 0)
+		return err;
+	err = usx2y_hwdep_pcm_new(card);
+	if (err < 0)
+		return err;
+	err = snd_card_register(card);
+	if (err < 0)
+		return err;
+	return 0;
+}
+
+static int snd_usx2y_hwdep_dsp_load(struct snd_hwdep *hw,
+				    struct snd_hwdep_dsp_image *dsp)
+{
+	struct usx2ydev *priv = hw->private_data;
+	struct usb_device *dev = priv->dev;
+	int lret, err;
+	char *buf;
+
+	buf = memdup_user(dsp->image, dsp->length);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	err = usb_set_interface(dev, 0, 1);
+	if (err)
+		dev_err(&dev->dev, "usb_set_interface error\n");
+	else
+		err = usb_bulk_msg(dev, usb_sndbulkpipe(dev, 2), buf, dsp->length, &lret, 6000);
+	kfree(buf);
+	if (err)
+		return err;
+	if (dsp->index == 1) {
+		msleep(250);				// give the device some time
+		err = usx2y_async_seq04_init(priv);
+		if (err) {
+			dev_err(&dev->dev, "usx2y_async_seq04_init error\n");
+			return err;
+		}
+		err = usx2y_in04_init(priv);
+		if (err) {
+			dev_err(&dev->dev, "usx2y_in04_init error\n");
+			return err;
+		}
+		err = usx2y_create_alsa_devices(hw->card);
+		if (err) {
+			dev_err(&dev->dev, "usx2y_create_alsa_devices error %i\n", err);
+			return err;
+		}
+		priv->chip_status |= USX2Y_STAT_CHIP_INIT;
+	}
+	return err;
+}
+
+int usx2y_hwdep_new(struct snd_card *card, struct usb_device *device)
+{
+	int err;
+	struct snd_hwdep *hw;
+	struct usx2ydev	*us428 = usx2y(card);
+
+	err = snd_hwdep_new(card, SND_USX2Y_LOADER_ID, 0, &hw);
+	if (err < 0)
+		return err;
+
+	hw->iface = SNDRV_HWDEP_IFACE_USX2Y;
+	hw->private_data = us428;
+	hw->ops.dsp_status = snd_usx2y_hwdep_dsp_status;
+	hw->ops.dsp_load = snd_usx2y_hwdep_dsp_load;
+	hw->ops.mmap = snd_us428ctls_mmap;
+	hw->ops.poll = snd_us428ctls_poll;
+	hw->exclusive = 1;
+	sprintf(hw->name, "/dev/bus/usb/%03d/%03d", device->bus->busnum, device->devnum);
+
+	us428->us428ctls_sharedmem = alloc_pages_exact(US428_SHAREDMEM_PAGES, GFP_KERNEL);
+	if (!us428->us428ctls_sharedmem)
+		return -ENOMEM;
+	memset(us428->us428ctls_sharedmem, -1, US428_SHAREDMEM_PAGES);
+	us428->us428ctls_sharedmem->ctl_snapshot_last = -2;
+
+	return 0;
+}
diff --git a/sound/usb/usx2y/usX2Yhwdep.h b/sound/usb/usx2y/usX2Yhwdep.h
new file mode 100644
index 000000000..0c9946d9c
--- /dev/null
+++ b/sound/usb/usx2y/usX2Yhwdep.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef USX2YHWDEP_H
+#define USX2YHWDEP_H
+
+int usx2y_hwdep_new(struct snd_card *card, struct usb_device *device);
+
+#endif
diff --git a/sound/usb/usx2y/usb_stream.c b/sound/usb/usx2y/usb_stream.c
new file mode 100644
index 000000000..3122cf653
--- /dev/null
+++ b/sound/usb/usx2y/usb_stream.c
@@ -0,0 +1,775 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2007, 2008 Karsten Wiese <fzu@wemgehoertderstaat.de>
+ */
+
+#include <linux/usb.h>
+#include <linux/gfp.h>
+
+#include "usb_stream.h"
+
+/*                             setup                                  */
+
+static unsigned int usb_stream_next_packet_size(struct usb_stream_kernel *sk)
+{
+	struct usb_stream *s = sk->s;
+
+	sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
+	return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
+}
+
+static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
+{
+	struct usb_stream *s = sk->s;
+	int pack, lb = 0;
+
+	for (pack = 0; pack < sk->n_o_ps; pack++) {
+		int l = usb_stream_next_packet_size(sk);
+
+		if (s->idle_outsize + lb + l > s->period_size)
+			goto check;
+
+		sk->out_phase = sk->out_phase_peeked;
+		urb->iso_frame_desc[pack].offset = lb;
+		urb->iso_frame_desc[pack].length = l;
+		lb += l;
+	}
+
+check:
+	urb->number_of_packets = pack;
+	urb->transfer_buffer_length = lb;
+	s->idle_outsize += lb - s->period_size;
+}
+
+static int init_pipe_urbs(struct usb_stream_kernel *sk,
+			  unsigned int use_packsize,
+			  struct urb **urbs, char *transfer,
+			  struct usb_device *dev, int pipe)
+{
+	int u, p;
+	int maxpacket = use_packsize ?
+		use_packsize : usb_maxpacket(dev, pipe);
+	int transfer_length = maxpacket * sk->n_o_ps;
+
+	for (u = 0; u < USB_STREAM_NURBS;
+	     ++u, transfer += transfer_length) {
+		struct urb *urb = urbs[u];
+		struct usb_iso_packet_descriptor *desc;
+
+		urb->transfer_buffer = transfer;
+		urb->dev = dev;
+		urb->pipe = pipe;
+		urb->number_of_packets = sk->n_o_ps;
+		urb->context = sk;
+		urb->interval = 1;
+		if (usb_pipeout(pipe))
+			continue;
+		if (usb_urb_ep_type_check(urb))
+			return -EINVAL;
+
+		urb->transfer_buffer_length = transfer_length;
+		desc = urb->iso_frame_desc;
+		desc->offset = 0;
+		desc->length = maxpacket;
+		for (p = 1; p < sk->n_o_ps; ++p) {
+			desc[p].offset = desc[p - 1].offset + maxpacket;
+			desc[p].length = maxpacket;
+		}
+	}
+
+	return 0;
+}
+
+static int init_urbs(struct usb_stream_kernel *sk, unsigned int use_packsize,
+		     struct usb_device *dev, int in_pipe, int out_pipe)
+{
+	struct usb_stream	*s = sk->s;
+	char			*indata =
+		(char *)s + sizeof(*s) + sizeof(struct usb_stream_packet) * s->inpackets;
+	int			u;
+
+	for (u = 0; u < USB_STREAM_NURBS; ++u) {
+		sk->inurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
+		if (!sk->inurb[u])
+			return -ENOMEM;
+
+		sk->outurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
+		if (!sk->outurb[u])
+			return -ENOMEM;
+	}
+
+	if (init_pipe_urbs(sk, use_packsize, sk->inurb, indata, dev, in_pipe) ||
+	    init_pipe_urbs(sk, use_packsize, sk->outurb, sk->write_page, dev,
+			   out_pipe))
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
+ * this will overflow at approx 524 kHz
+ */
+static inline unsigned int get_usb_full_speed_rate(unsigned int rate)
+{
+	return ((rate << 13) + 62) / 125;
+}
+
+/*
+ * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
+ * this will overflow at approx 4 MHz
+ */
+static inline unsigned int get_usb_high_speed_rate(unsigned int rate)
+{
+	return ((rate << 10) + 62) / 125;
+}
+
+void usb_stream_free(struct usb_stream_kernel *sk)
+{
+	struct usb_stream *s;
+	unsigned int u;
+
+	for (u = 0; u < USB_STREAM_NURBS; ++u) {
+		usb_free_urb(sk->inurb[u]);
+		sk->inurb[u] = NULL;
+		usb_free_urb(sk->outurb[u]);
+		sk->outurb[u] = NULL;
+	}
+
+	s = sk->s;
+	if (!s)
+		return;
+
+	if (sk->write_page) {
+		free_pages_exact(sk->write_page, s->write_size);
+		sk->write_page = NULL;
+	}
+
+	free_pages_exact(s, s->read_size);
+	sk->s = NULL;
+}
+
+struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
+				  struct usb_device *dev,
+				  unsigned int in_endpoint,
+				  unsigned int out_endpoint,
+				  unsigned int sample_rate,
+				  unsigned int use_packsize,
+				  unsigned int period_frames,
+				  unsigned int frame_size)
+{
+	int packets, max_packsize;
+	int in_pipe, out_pipe;
+	int read_size = sizeof(struct usb_stream);
+	int write_size;
+	int usb_frames = dev->speed == USB_SPEED_HIGH ? 8000 : 1000;
+
+	in_pipe = usb_rcvisocpipe(dev, in_endpoint);
+	out_pipe = usb_sndisocpipe(dev, out_endpoint);
+
+	max_packsize = use_packsize ?
+		use_packsize : usb_maxpacket(dev, in_pipe);
+
+	/*
+		t_period = period_frames / sample_rate
+		iso_packs = t_period / t_iso_frame
+			= (period_frames / sample_rate) * (1 / t_iso_frame)
+	*/
+
+	packets = period_frames * usb_frames / sample_rate + 1;
+
+	if (dev->speed == USB_SPEED_HIGH)
+		packets = (packets + 7) & ~7;
+
+	read_size += packets * USB_STREAM_URBDEPTH *
+		(max_packsize + sizeof(struct usb_stream_packet));
+
+	max_packsize = usb_maxpacket(dev, out_pipe);
+	write_size = max_packsize * packets * USB_STREAM_URBDEPTH;
+
+	if (read_size >= 256*PAGE_SIZE || write_size >= 256*PAGE_SIZE) {
+		dev_warn(&dev->dev, "%s: a size exceeds 128*PAGE_SIZE\n", __func__);
+		goto out;
+	}
+
+	sk->s = alloc_pages_exact(read_size,
+				  GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
+	if (!sk->s) {
+		dev_warn(&dev->dev, "us122l: couldn't allocate read buffer\n");
+		goto out;
+	}
+	sk->s->cfg.version = USB_STREAM_INTERFACE_VERSION;
+
+	sk->s->read_size = read_size;
+
+	sk->s->cfg.sample_rate = sample_rate;
+	sk->s->cfg.frame_size = frame_size;
+	sk->n_o_ps = packets;
+	sk->s->inpackets = packets * USB_STREAM_URBDEPTH;
+	sk->s->cfg.period_frames = period_frames;
+	sk->s->period_size = frame_size * period_frames;
+
+	sk->s->write_size = write_size;
+
+	sk->write_page = alloc_pages_exact(write_size,
+					   GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
+	if (!sk->write_page) {
+		dev_warn(&dev->dev, "us122l: couldn't allocate write buffer\n");
+		usb_stream_free(sk);
+		return NULL;
+	}
+
+	/* calculate the frequency in 16.16 format */
+	if (dev->speed == USB_SPEED_FULL)
+		sk->freqn = get_usb_full_speed_rate(sample_rate);
+	else
+		sk->freqn = get_usb_high_speed_rate(sample_rate);
+
+	if (init_urbs(sk, use_packsize, dev, in_pipe, out_pipe) < 0) {
+		usb_stream_free(sk);
+		return NULL;
+	}
+
+	sk->s->state = usb_stream_stopped;
+out:
+	return sk->s;
+}
+
+/*                             start                                  */
+
+static bool balance_check(struct usb_stream_kernel *sk, struct urb *urb)
+{
+	bool r;
+
+	if (unlikely(urb->status)) {
+		if (urb->status != -ESHUTDOWN && urb->status != -ENOENT)
+			dev_warn(&sk->dev->dev, "%s: status=%i\n", __func__,
+				 urb->status);
+		sk->iso_frame_balance = 0x7FFFFFFF;
+		return false;
+	}
+	r = sk->iso_frame_balance == 0;
+	if (!r)
+		sk->i_urb = urb;
+	return r;
+}
+
+static bool balance_playback(struct usb_stream_kernel *sk, struct urb *urb)
+{
+	sk->iso_frame_balance += urb->number_of_packets;
+	return balance_check(sk, urb);
+}
+
+static bool balance_capture(struct usb_stream_kernel *sk, struct urb *urb)
+{
+	sk->iso_frame_balance -= urb->number_of_packets;
+	return balance_check(sk, urb);
+}
+
+static void subs_set_complete(struct urb **urbs, void (*complete)(struct urb *))
+{
+	int u;
+
+	for (u = 0; u < USB_STREAM_NURBS; u++) {
+		struct urb *urb = urbs[u];
+
+		urb->complete = complete;
+	}
+}
+
+static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
+		struct urb *inurb)
+{
+	struct usb_stream *s = sk->s;
+	struct urb *io;
+	struct usb_iso_packet_descriptor *id, *od;
+	int p = 0, lb = 0, l = 0;
+
+	io = sk->idle_outurb;
+	od = io->iso_frame_desc;
+
+	for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
+		struct urb *ii = sk->completed_inurb;
+
+		id = ii->iso_frame_desc +
+			ii->number_of_packets + s->sync_packet;
+		l = id->actual_length;
+
+		od[p].length = l;
+		od[p].offset = lb;
+		lb += l;
+	}
+
+	for (;
+	     s->sync_packet < inurb->number_of_packets && p < sk->n_o_ps;
+	     ++p, ++s->sync_packet) {
+		l = inurb->iso_frame_desc[s->sync_packet].actual_length;
+
+		if (s->idle_outsize + lb + l > s->period_size)
+			goto check_ok;
+
+		od[p].length = l;
+		od[p].offset = lb;
+		lb += l;
+	}
+
+check_ok:
+	s->sync_packet -= inurb->number_of_packets;
+	if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
+		dev_warn(&sk->dev->dev,
+			 "%s: invalid sync_packet = %i; p=%i nop=%i %i %x %x %x > %x\n",
+			 __func__,
+			 s->sync_packet, p, inurb->number_of_packets,
+			 s->idle_outsize + lb + l,
+			 s->idle_outsize, lb,  l,
+			 s->period_size);
+		return -1;
+	}
+	if (unlikely(lb % s->cfg.frame_size)) {
+		dev_warn(&sk->dev->dev, "%s: invalid outsize = %i\n",
+			 __func__, lb);
+		return -1;
+	}
+	s->idle_outsize += lb - s->period_size;
+	io->number_of_packets = p;
+	io->transfer_buffer_length = lb;
+	if (s->idle_outsize <= 0)
+		return 0;
+
+	dev_warn(&sk->dev->dev, "%s: idle=%i\n", __func__, s->idle_outsize);
+	return -1;
+}
+
+static void prepare_inurb(int number_of_packets, struct urb *iu)
+{
+	struct usb_iso_packet_descriptor *id;
+	int p;
+
+	iu->number_of_packets = number_of_packets;
+	id = iu->iso_frame_desc;
+	id->offset = 0;
+	for (p = 0; p < iu->number_of_packets - 1; ++p)
+		id[p + 1].offset = id[p].offset + id[p].length;
+
+	iu->transfer_buffer_length =
+		id[0].length * iu->number_of_packets;
+}
+
+static int submit_urbs(struct usb_stream_kernel *sk,
+		       struct urb *inurb, struct urb *outurb)
+{
+	int err;
+
+	prepare_inurb(sk->idle_outurb->number_of_packets, sk->idle_inurb);
+	err = usb_submit_urb(sk->idle_inurb, GFP_ATOMIC);
+	if (err < 0)
+		goto report_failure;
+
+	sk->idle_inurb = sk->completed_inurb;
+	sk->completed_inurb = inurb;
+	err = usb_submit_urb(sk->idle_outurb, GFP_ATOMIC);
+	if (err < 0)
+		goto report_failure;
+
+	sk->idle_outurb = sk->completed_outurb;
+	sk->completed_outurb = outurb;
+	return 0;
+
+report_failure:
+	dev_err(&sk->dev->dev, "%s error: %i\n", __func__, err);
+	return err;
+}
+
+#ifdef DEBUG_LOOP_BACK
+/*
+  This loop_back() shows how to read/write the period data.
+ */
+static void loop_back(struct usb_stream *s)
+{
+	char *i, *o;
+	int il, ol, l, p;
+	struct urb *iu;
+	struct usb_iso_packet_descriptor *id;
+
+	o = s->playback1st_to;
+	ol = s->playback1st_size;
+	l = 0;
+
+	if (s->insplit_pack >= 0) {
+		iu = sk->idle_inurb;
+		id = iu->iso_frame_desc;
+		p = s->insplit_pack;
+	} else
+		goto second;
+loop:
+	for (; p < iu->number_of_packets && l < s->period_size; ++p) {
+		i = iu->transfer_buffer + id[p].offset;
+		il = id[p].actual_length;
+		if (l + il > s->period_size)
+			il = s->period_size - l;
+		if (il <= ol) {
+			memcpy(o, i, il);
+			o += il;
+			ol -= il;
+		} else {
+			memcpy(o, i, ol);
+			singen_6pack(o, ol);
+			o = s->playback_to;
+			memcpy(o, i + ol, il - ol);
+			o += il - ol;
+			ol = s->period_size - s->playback1st_size;
+		}
+		l += il;
+	}
+	if (iu == sk->completed_inurb) {
+		if (l != s->period_size)
+			dev_dbg(&sk->dev->dev, "%s:%i %i\n", __func__, __LINE__,
+				l/(int)s->cfg.frame_size);
+
+		return;
+	}
+second:
+	iu = sk->completed_inurb;
+	id = iu->iso_frame_desc;
+	p = 0;
+	goto loop;
+
+}
+#else
+static void loop_back(struct usb_stream *s)
+{
+}
+#endif
+
+static void stream_idle(struct usb_stream_kernel *sk,
+			struct urb *inurb, struct urb *outurb)
+{
+	struct usb_stream *s = sk->s;
+	int l, p;
+	int insize = s->idle_insize;
+	int urb_size = 0;
+
+	s->inpacket_split = s->next_inpacket_split;
+	s->inpacket_split_at = s->next_inpacket_split_at;
+	s->next_inpacket_split = -1;
+	s->next_inpacket_split_at = 0;
+
+	for (p = 0; p < inurb->number_of_packets; ++p) {
+		struct usb_iso_packet_descriptor *id = inurb->iso_frame_desc;
+
+		l = id[p].actual_length;
+		if (unlikely(l == 0 || id[p].status)) {
+			dev_warn(&sk->dev->dev, "%s: underrun, status=%u\n",
+				 __func__, id[p].status);
+			goto err_out;
+		}
+		s->inpacket_head++;
+		s->inpacket_head %= s->inpackets;
+		if (s->inpacket_split == -1)
+			s->inpacket_split = s->inpacket_head;
+
+		s->inpacket[s->inpacket_head].offset =
+			id[p].offset + (inurb->transfer_buffer - (void *)s);
+		s->inpacket[s->inpacket_head].length = l;
+		if (insize + l > s->period_size &&
+		    s->next_inpacket_split == -1) {
+			s->next_inpacket_split = s->inpacket_head;
+			s->next_inpacket_split_at = s->period_size - insize;
+		}
+		insize += l;
+		urb_size += l;
+	}
+	s->idle_insize += urb_size - s->period_size;
+	if (s->idle_insize < 0) {
+		dev_warn(&sk->dev->dev, "%s error: %i\n", __func__,
+			 (s->idle_insize)/(int)s->cfg.frame_size);
+		goto err_out;
+	}
+	s->insize_done += urb_size;
+
+	l = s->idle_outsize;
+	s->outpacket[0].offset = (sk->idle_outurb->transfer_buffer -
+				  sk->write_page) - l;
+
+	if (usb_stream_prepare_playback(sk, inurb) < 0)
+		goto err_out;
+
+	s->outpacket[0].length = sk->idle_outurb->transfer_buffer_length + l;
+	s->outpacket[1].offset = sk->completed_outurb->transfer_buffer -
+		sk->write_page;
+
+	if (submit_urbs(sk, inurb, outurb) < 0)
+		goto err_out;
+
+	loop_back(s);
+	s->periods_done++;
+	wake_up_all(&sk->sleep);
+	return;
+err_out:
+	s->state = usb_stream_xrun;
+	wake_up_all(&sk->sleep);
+}
+
+static void i_capture_idle(struct urb *urb)
+{
+	struct usb_stream_kernel *sk = urb->context;
+
+	if (balance_capture(sk, urb))
+		stream_idle(sk, urb, sk->i_urb);
+}
+
+static void i_playback_idle(struct urb *urb)
+{
+	struct usb_stream_kernel *sk = urb->context;
+
+	if (balance_playback(sk, urb))
+		stream_idle(sk, sk->i_urb, urb);
+}
+
+static void stream_start(struct usb_stream_kernel *sk,
+			 struct urb *inurb, struct urb *outurb)
+{
+	struct usb_stream *s = sk->s;
+
+	if (s->state >= usb_stream_sync1) {
+		int l, p, max_diff, max_diff_0;
+		int urb_size = 0;
+		unsigned int frames_per_packet, min_frames = 0;
+
+		frames_per_packet = (s->period_size - s->idle_insize);
+		frames_per_packet <<= 8;
+		frames_per_packet /=
+			s->cfg.frame_size * inurb->number_of_packets;
+		frames_per_packet++;
+
+		max_diff_0 = s->cfg.frame_size;
+		if (s->cfg.period_frames >= 256)
+			max_diff_0 <<= 1;
+		if (s->cfg.period_frames >= 1024)
+			max_diff_0 <<= 1;
+		max_diff = max_diff_0;
+		for (p = 0; p < inurb->number_of_packets; ++p) {
+			int diff;
+
+			l = inurb->iso_frame_desc[p].actual_length;
+			urb_size += l;
+
+			min_frames += frames_per_packet;
+			diff = urb_size -
+				(min_frames >> 8) * s->cfg.frame_size;
+			if (diff < max_diff)
+				max_diff = diff;
+		}
+		s->idle_insize -= max_diff - max_diff_0;
+		s->idle_insize += urb_size - s->period_size;
+		if (s->idle_insize < 0) {
+			dev_warn(&sk->dev->dev, "%s idle_insize: %i %i %i\n",
+				 __func__,
+				 s->idle_insize, urb_size, s->period_size);
+			return;
+		} else if (s->idle_insize == 0) {
+			s->next_inpacket_split =
+				(s->inpacket_head + 1) % s->inpackets;
+			s->next_inpacket_split_at = 0;
+		} else {
+			unsigned int split = s->inpacket_head;
+
+			l = s->idle_insize;
+			while (l > s->inpacket[split].length) {
+				l -= s->inpacket[split].length;
+				if (split == 0)
+					split = s->inpackets - 1;
+				else
+					split--;
+			}
+			s->next_inpacket_split = split;
+			s->next_inpacket_split_at =
+				s->inpacket[split].length - l;
+		}
+
+		s->insize_done += urb_size;
+
+		if (usb_stream_prepare_playback(sk, inurb) < 0)
+			return;
+
+	} else
+		playback_prep_freqn(sk, sk->idle_outurb);
+
+	if (submit_urbs(sk, inurb, outurb) < 0)
+		return;
+
+	if (s->state == usb_stream_sync1 && s->insize_done > 360000) {
+		/* just guesswork                            ^^^^^^ */
+		s->state = usb_stream_ready;
+		subs_set_complete(sk->inurb, i_capture_idle);
+		subs_set_complete(sk->outurb, i_playback_idle);
+	}
+}
+
+static void i_capture_start(struct urb *urb)
+{
+	struct usb_iso_packet_descriptor *id = urb->iso_frame_desc;
+	struct usb_stream_kernel *sk = urb->context;
+	struct usb_stream *s = sk->s;
+	int p;
+	int empty = 0;
+
+	if (urb->status) {
+		dev_warn(&sk->dev->dev, "%s: status=%i\n", __func__, urb->status);
+		return;
+	}
+
+	for (p = 0; p < urb->number_of_packets; ++p) {
+		int l = id[p].actual_length;
+
+		if (l < s->cfg.frame_size) {
+			++empty;
+			if (s->state >= usb_stream_sync0) {
+				dev_warn(&sk->dev->dev, "%s: length %i\n", __func__, l);
+				return;
+			}
+		}
+		s->inpacket_head++;
+		s->inpacket_head %= s->inpackets;
+		s->inpacket[s->inpacket_head].offset =
+			id[p].offset + (urb->transfer_buffer - (void *)s);
+		s->inpacket[s->inpacket_head].length = l;
+	}
+#ifdef SHOW_EMPTY
+	if (empty) {
+		dev_dbg(&sk->dev->dev, "%s:%i: %i", __func__, __LINE__,
+			urb->iso_frame_desc[0].actual_length);
+		for (pack = 1; pack < urb->number_of_packets; ++pack) {
+			int l = urb->iso_frame_desc[pack].actual_length;
+
+			printk(KERN_CONT " %i", l);
+		}
+		printk(KERN_CONT "\n");
+	}
+#endif
+	if (!empty && s->state < usb_stream_sync1)
+		++s->state;
+
+	if (balance_capture(sk, urb))
+		stream_start(sk, urb, sk->i_urb);
+}
+
+static void i_playback_start(struct urb *urb)
+{
+	struct usb_stream_kernel *sk = urb->context;
+
+	if (balance_playback(sk, urb))
+		stream_start(sk, sk->i_urb, urb);
+}
+
+int usb_stream_start(struct usb_stream_kernel *sk)
+{
+	struct usb_stream *s = sk->s;
+	int frame = 0;
+	int u, err;
+	int try = 0;
+
+	if (s->state != usb_stream_stopped)
+		return -EAGAIN;
+
+	subs_set_complete(sk->inurb, i_capture_start);
+	subs_set_complete(sk->outurb, i_playback_start);
+	memset(sk->write_page, 0, s->write_size);
+dotry:
+	s->insize_done = 0;
+	s->idle_insize = 0;
+	s->idle_outsize = 0;
+	s->sync_packet = -1;
+	s->inpacket_head = -1;
+	sk->iso_frame_balance = 0;
+	++try;
+	for (u = 0; u < 2; u++) {
+		struct urb *inurb = sk->inurb[u];
+		struct urb *outurb = sk->outurb[u];
+
+		playback_prep_freqn(sk, outurb);
+		inurb->number_of_packets = outurb->number_of_packets;
+		inurb->transfer_buffer_length =
+			inurb->number_of_packets *
+			inurb->iso_frame_desc[0].length;
+
+		if (u == 0) {
+			int now;
+			struct usb_device *dev = inurb->dev;
+
+			frame = usb_get_current_frame_number(dev);
+			do {
+				now = usb_get_current_frame_number(dev);
+			} while (now > -1 && now == frame);
+		}
+		err = usb_submit_urb(inurb, GFP_ATOMIC);
+		if (err < 0) {
+			dev_err(&sk->dev->dev,
+				"%s: usb_submit_urb(sk->inurb[%i]) returned %i\n",
+				__func__, u, err);
+			return err;
+		}
+		err = usb_submit_urb(outurb, GFP_ATOMIC);
+		if (err < 0) {
+			dev_err(&sk->dev->dev,
+				"%s: usb_submit_urb(sk->outurb[%i]) returned %i\n",
+				__func__, u, err);
+			return err;
+		}
+
+		if (inurb->start_frame != outurb->start_frame) {
+			dev_dbg(&sk->dev->dev,
+				"%s: u[%i] start_frames differ in:%u out:%u\n",
+				__func__, u, inurb->start_frame, outurb->start_frame);
+			goto check_retry;
+		}
+	}
+	try = 0;
+check_retry:
+	if (try) {
+		usb_stream_stop(sk);
+		if (try < 5) {
+			msleep(1500);
+			dev_dbg(&sk->dev->dev, "goto dotry;\n");
+			goto dotry;
+		}
+		dev_warn(&sk->dev->dev,
+			 "%s: couldn't start all urbs on the same start_frame.\n",
+			 __func__);
+		return -EFAULT;
+	}
+
+	sk->idle_inurb = sk->inurb[USB_STREAM_NURBS - 2];
+	sk->idle_outurb = sk->outurb[USB_STREAM_NURBS - 2];
+	sk->completed_inurb = sk->inurb[USB_STREAM_NURBS - 1];
+	sk->completed_outurb = sk->outurb[USB_STREAM_NURBS - 1];
+
+/* wait, check */
+	{
+		int wait_ms = 3000;
+
+		while (s->state != usb_stream_ready && wait_ms > 0) {
+			msleep(200);
+			wait_ms -= 200;
+		}
+	}
+
+	return s->state == usb_stream_ready ? 0 : -EFAULT;
+}
+
+
+/*                             stop                                   */
+
+void usb_stream_stop(struct usb_stream_kernel *sk)
+{
+	int u;
+
+	if (!sk->s)
+		return;
+	for (u = 0; u < USB_STREAM_NURBS; ++u) {
+		usb_kill_urb(sk->inurb[u]);
+		usb_kill_urb(sk->outurb[u]);
+	}
+	sk->s->state = usb_stream_stopped;
+	msleep(400);
+}
diff --git a/sound/usb/usx2y/usb_stream.h b/sound/usb/usx2y/usb_stream.h
new file mode 100644
index 000000000..2ed10add4
--- /dev/null
+++ b/sound/usb/usx2y/usb_stream.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USB_STREAM_H
+#define __USB_STREAM_H
+
+#include <uapi/sound/usb_stream.h>
+
+#define USB_STREAM_NURBS 4
+#define USB_STREAM_URBDEPTH 4
+
+struct usb_stream_kernel {
+	struct usb_stream *s;
+	struct usb_device *dev;
+
+	void *write_page;
+
+	unsigned int n_o_ps;
+
+	struct urb *inurb[USB_STREAM_NURBS];
+	struct urb *idle_inurb;
+	struct urb *completed_inurb;
+	struct urb *outurb[USB_STREAM_NURBS];
+	struct urb *idle_outurb;
+	struct urb *completed_outurb;
+	struct urb *i_urb;
+
+	int iso_frame_balance;
+
+	wait_queue_head_t sleep;
+
+	unsigned int out_phase;
+	unsigned int out_phase_peeked;
+	unsigned int freqn;
+};
+
+struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
+				  struct usb_device *dev,
+				  unsigned int in_endpoint,
+				  unsigned int out_endpoint,
+				  unsigned int sample_rate,
+				  unsigned int use_packsize,
+				  unsigned int period_frames,
+				  unsigned int frame_size);
+void usb_stream_free(struct usb_stream_kernel *sk);
+int usb_stream_start(struct usb_stream_kernel *sk);
+void usb_stream_stop(struct usb_stream_kernel *sk);
+
+#endif /* __USB_STREAM_H */
diff --git a/sound/usb/usx2y/usbus428ctldefs.h b/sound/usb/usx2y/usbus428ctldefs.h
new file mode 100644
index 000000000..9ba15d974
--- /dev/null
+++ b/sound/usb/usx2y/usbus428ctldefs.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *
+ * Copyright (c) 2003 by Karsten Wiese <annabellesgarden@yahoo.de>
+ */
+
+enum E_IN84 {
+	E_FADER_0 = 0,
+	E_FADER_1,
+	E_FADER_2,
+	E_FADER_3,
+	E_FADER_4,
+	E_FADER_5,
+	E_FADER_6,
+	E_FADER_7,
+	E_FADER_M,
+	E_TRANSPORT,
+	E_MODIFIER = 10,
+	E_FILTER_SELECT,
+	E_SELECT,
+	E_MUTE,
+
+	E_SWITCH   = 15,
+	E_WHEEL_GAIN,
+	E_WHEEL_FREQ,
+	E_WHEEL_Q,
+	E_WHEEL_PAN,
+	E_WHEEL    = 20
+};
+
+#define T_RECORD   1
+#define T_PLAY     2
+#define T_STOP     4
+#define T_F_FWD    8
+#define T_REW   0x10
+#define T_SOLO  0x20
+#define T_REC   0x40
+#define T_NULL  0x80
+
+
+struct us428_ctls {
+	unsigned char	fader[9];
+	unsigned char	transport;
+	unsigned char	modifier;
+	unsigned char	filters_elect;
+	unsigned char	select;
+	unsigned char	mute;
+	unsigned char	unknown;
+	unsigned char	wswitch;
+	unsigned char	wheel[5];
+};
+
+struct us428_set_byte {
+	unsigned char offset,
+		value;
+};
+
+enum {
+	ELT_VOLUME = 0,
+	ELT_LIGHT
+};
+
+struct usx2y_volume {
+	unsigned char channel,
+		lh,
+		ll,
+		rh,
+		rl;
+};
+
+struct us428_lights {
+	struct us428_set_byte light[7];
+};
+
+struct us428_p4out {
+	char type;
+	union {
+		struct usx2y_volume vol;
+		struct us428_lights lights;
+	} val;
+};
+
+#define N_US428_CTL_BUFS 16
+#define N_US428_P4OUT_BUFS 16
+struct us428ctls_sharedmem {
+	struct us428_ctls	ctl_snapshot[N_US428_CTL_BUFS];
+	int			ctl_snapshot_differs_at[N_US428_CTL_BUFS];
+	int			ctl_snapshot_last, ctl_snapshot_red;
+	struct us428_p4out	p4out[N_US428_P4OUT_BUFS];
+	int			p4out_last, p4out_sent;
+};
+
+#define US428_SHAREDMEM_PAGES	PAGE_ALIGN(sizeof(struct us428ctls_sharedmem))
diff --git a/sound/usb/usx2y/usbusx2y.c b/sound/usb/usx2y/usbusx2y.c
new file mode 100644
index 000000000..108f9bddf
--- /dev/null
+++ b/sound/usb/usx2y/usbusx2y.c
@@ -0,0 +1,487 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * usbusx2y.c - ALSA USB US-428 Driver
+ *
+2005-04-14 Karsten Wiese
+	Version 0.8.7.2:
+	Call snd_card_free() instead of snd_card_free_in_thread() to prevent oops with dead keyboard symptom.
+	Tested ok with kernel 2.6.12-rc2.
+
+2004-12-14 Karsten Wiese
+	Version 0.8.7.1:
+	snd_pcm_open for rawusb pcm-devices now returns -EBUSY if called without rawusb's hwdep device being open.
+
+2004-12-02 Karsten Wiese
+	Version 0.8.7:
+	Use macro usb_maxpacket() for portability.
+
+2004-10-26 Karsten Wiese
+	Version 0.8.6:
+	wake_up() process waiting in usx2y_urbs_start() on error.
+
+2004-10-21 Karsten Wiese
+	Version 0.8.5:
+	nrpacks is runtime or compiletime configurable now with tested values from 1 to 4.
+
+2004-10-03 Karsten Wiese
+	Version 0.8.2:
+	Avoid any possible racing while in prepare callback.
+
+2004-09-30 Karsten Wiese
+	Version 0.8.0:
+	Simplified things and made ohci work again.
+
+2004-09-20 Karsten Wiese
+	Version 0.7.3:
+	Use usb_kill_urb() instead of deprecated (kernel 2.6.9) usb_unlink_urb().
+
+2004-07-13 Karsten Wiese
+	Version 0.7.1:
+	Don't sleep in START/STOP callbacks anymore.
+	us428 channels C/D not handled just for this version, sorry.
+
+2004-06-21 Karsten Wiese
+	Version 0.6.4:
+	Temporarely suspend midi input
+	to sanely call usb_set_interface() when setting format.
+
+2004-06-12 Karsten Wiese
+	Version 0.6.3:
+	Made it thus the following rule is enforced:
+	"All pcm substreams of one usx2y have to operate at the same rate & format."
+
+2004-04-06 Karsten Wiese
+	Version 0.6.0:
+	Runs on 2.6.5 kernel without any "--with-debug=" things.
+	us224 reported running.
+
+2004-01-14 Karsten Wiese
+	Version 0.5.1:
+	Runs with 2.6.1 kernel.
+
+2003-12-30 Karsten Wiese
+	Version 0.4.1:
+	Fix 24Bit 4Channel capturing for the us428.
+
+2003-11-27 Karsten Wiese, Martin Langer
+	Version 0.4:
+	us122 support.
+	us224 could be tested by uncommenting the sections containing USB_ID_US224
+
+2003-11-03 Karsten Wiese
+	Version 0.3:
+	24Bit support.
+	"arecord -D hw:1 -c 2 -r 48000 -M -f S24_3LE|aplay -D hw:1 -c 2 -r 48000 -M -f S24_3LE" works.
+
+2003-08-22 Karsten Wiese
+	Version 0.0.8:
+	Removed EZUSB Firmware. First Stage Firmwaredownload is now done by tascam-firmware downloader.
+	See:
+	http://usb-midi-fw.sourceforge.net/tascam-firmware.tar.gz
+
+2003-06-18 Karsten Wiese
+	Version 0.0.5:
+	changed to compile with kernel 2.4.21 and alsa 0.9.4
+
+2002-10-16 Karsten Wiese
+	Version 0.0.4:
+	compiles again with alsa-current.
+	USB_ISO_ASAP not used anymore (most of the time), instead
+	urb->start_frame is calculated here now, some calls inside usb-driver don't need to happen anymore.
+
+	To get the best out of this:
+	Disable APM-support in the kernel as APM-BIOS calls (once each second) hard disable interrupt for many precious milliseconds.
+	This helped me much on my slowish PII 400 & PIII 500.
+	ACPI yet untested but might cause the same bad behaviour.
+	Use a kernel with lowlatency and preemptiv patches applied.
+	To autoload snd-usb-midi append a line
+		post-install snd-usb-us428 modprobe snd-usb-midi
+	to /etc/modules.conf.
+
+	known problems:
+	sliders, knobs, lights not yet handled except MASTER Volume slider.
+	"pcm -c 2" doesn't work. "pcm -c 2 -m direct_interleaved" does.
+	KDE3: "Enable full duplex operation" deadlocks.
+
+2002-08-31 Karsten Wiese
+	Version 0.0.3: audio also simplex;
+	simplifying: iso urbs only 1 packet, melted structs.
+	ASYNC_UNLINK not used anymore: no more crashes so far.....
+	for alsa 0.9 rc3.
+
+2002-08-09 Karsten Wiese
+	Version 0.0.2: midi works with snd-usb-midi, audio (only fullduplex now) with i.e. bristol.
+	The firmware has been sniffed from win2k us-428 driver 3.09.
+
+ *   Copyright (c) 2002 - 2004 Karsten Wiese
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/usb.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+
+#include <sound/rawmidi.h>
+#include "usx2y.h"
+#include "usbusx2y.h"
+#include "usX2Yhwdep.h"
+
+MODULE_AUTHOR("Karsten Wiese <annabellesgarden@yahoo.de>");
+MODULE_DESCRIPTION("TASCAM "NAME_ALLCAPS" Version 0.8.7.2");
+MODULE_LICENSE("GPL");
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-max */
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* Id for this card */
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP; /* Enable this card */
+
+module_param_array(index, int, NULL, 0444);
+MODULE_PARM_DESC(index, "Index value for "NAME_ALLCAPS".");
+module_param_array(id, charp, NULL, 0444);
+MODULE_PARM_DESC(id, "ID string for "NAME_ALLCAPS".");
+module_param_array(enable, bool, NULL, 0444);
+MODULE_PARM_DESC(enable, "Enable "NAME_ALLCAPS".");
+
+static int snd_usx2y_card_used[SNDRV_CARDS];
+
+static void snd_usx2y_card_private_free(struct snd_card *card);
+static void usx2y_unlinkseq(struct snd_usx2y_async_seq *s);
+
+#ifdef USX2Y_NRPACKS_VARIABLE
+int nrpacks = USX2Y_NRPACKS; /* number of packets per urb */
+module_param(nrpacks, int, 0444);
+MODULE_PARM_DESC(nrpacks, "Number of packets per URB.");
+#endif
+
+/*
+ * pipe 4 is used for switching the lamps, setting samplerate, volumes ....
+ */
+static void i_usx2y_out04_int(struct urb *urb)
+{
+#ifdef CONFIG_SND_DEBUG
+	if (urb->status) {
+		int i;
+		struct usx2ydev *usx2y = urb->context;
+
+		for (i = 0; i < 10 && usx2y->as04.urb[i] != urb; i++)
+			;
+		dev_dbg(&urb->dev->dev, "%s urb %i status=%i\n", __func__, i, urb->status);
+	}
+#endif
+}
+
+static void i_usx2y_in04_int(struct urb *urb)
+{
+	int			err = 0;
+	struct usx2ydev		*usx2y = urb->context;
+	struct us428ctls_sharedmem	*us428ctls = usx2y->us428ctls_sharedmem;
+	struct us428_p4out *p4out;
+	int i, j, n, diff, send, len;
+
+	usx2y->in04_int_calls++;
+
+	if (urb->status) {
+		dev_dbg(&urb->dev->dev, "Interrupt Pipe 4 came back with status=%i\n", urb->status);
+		return;
+	}
+
+	if (urb->actual_length < USX2Y_IN04_SIZE)
+		goto resubmit;
+
+	if (us428ctls) {
+		diff = -1;
+		if (us428ctls->ctl_snapshot_last == -2) {
+			diff = 0;
+			memcpy(usx2y->in04_last, usx2y->in04_buf, sizeof(usx2y->in04_last));
+			us428ctls->ctl_snapshot_last = -1;
+		} else {
+			for (i = 0; i < USX2Y_IN04_SIZE; i++) {
+				if (usx2y->in04_last[i] != ((char *)usx2y->in04_buf)[i]) {
+					if (diff < 0)
+						diff = i;
+					usx2y->in04_last[i] = ((char *)usx2y->in04_buf)[i];
+				}
+			}
+		}
+		if (diff >= 0) {
+			n = us428ctls->ctl_snapshot_last + 1;
+			if (n >= N_US428_CTL_BUFS || n < 0)
+				n = 0;
+			memcpy(us428ctls->ctl_snapshot + n, usx2y->in04_buf, sizeof(us428ctls->ctl_snapshot[0]));
+			us428ctls->ctl_snapshot_differs_at[n] = diff;
+			us428ctls->ctl_snapshot_last = n;
+			wake_up(&usx2y->us428ctls_wait_queue_head);
+		}
+	}
+
+	if (usx2y->us04) {
+		if (!usx2y->us04->submitted) {
+			do {
+				err = usb_submit_urb(usx2y->us04->urb[usx2y->us04->submitted++], GFP_ATOMIC);
+			} while (!err && usx2y->us04->submitted < usx2y->us04->len);
+		}
+	} else {
+		while (us428ctls &&
+		       us428ctls->p4out_last >= 0 &&
+		       us428ctls->p4out_last < N_US428_P4OUT_BUFS &&
+		       us428ctls->p4out_last != us428ctls->p4out_sent) {
+			for (j = 0; j < URBS_ASYNC_SEQ && !err; ++j) {
+				if (!usx2y->as04.urb[j]->status) {
+					send = us428ctls->p4out_sent + 1;
+					if (send >= N_US428_P4OUT_BUFS)
+						send = 0;
+
+					p4out = us428ctls->p4out + send;
+					len = p4out->type == ELT_LIGHT ?
+						sizeof(struct us428_lights) : 5;
+					memcpy(usx2y->as04.urb[j]->transfer_buffer,
+					       &p4out->val.vol, len);
+					usx2y->as04.urb[j]->transfer_buffer_length = len;
+					err = usb_submit_urb(usx2y->as04.urb[j], GFP_ATOMIC);
+					if (!err)
+						us428ctls->p4out_sent = send;
+
+					break;
+				}
+			}
+			if (j >= URBS_ASYNC_SEQ || err)
+				break;
+		}
+	}
+
+	if (err)
+		dev_err(&urb->dev->dev, "in04_int() usb_submit_urb err=%i\n", err);
+
+resubmit:
+	urb->dev = usx2y->dev;
+	usb_submit_urb(urb, GFP_ATOMIC);
+}
+
+/*
+ * Prepare some urbs
+ */
+int usx2y_async_seq04_init(struct usx2ydev *usx2y)
+{
+	int	err = 0, i;
+
+	if (WARN_ON(usx2y->as04.buffer))
+		return -EBUSY;
+
+	usx2y->as04.buffer = kmalloc_array(URBS_ASYNC_SEQ,
+					   URB_DATA_LEN_ASYNC_SEQ, GFP_KERNEL);
+	if (!usx2y->as04.buffer) {
+		err = -ENOMEM;
+	} else {
+		for (i = 0; i < URBS_ASYNC_SEQ; ++i) {
+			usx2y->as04.urb[i] = usb_alloc_urb(0, GFP_KERNEL);
+			if (!usx2y->as04.urb[i]) {
+				err = -ENOMEM;
+				break;
+			}
+			usb_fill_bulk_urb(usx2y->as04.urb[i], usx2y->dev,
+					  usb_sndbulkpipe(usx2y->dev, 0x04),
+					  usx2y->as04.buffer + URB_DATA_LEN_ASYNC_SEQ * i, 0,
+					  i_usx2y_out04_int, usx2y);
+			err = usb_urb_ep_type_check(usx2y->as04.urb[i]);
+			if (err < 0)
+				break;
+		}
+	}
+	if (err)
+		usx2y_unlinkseq(&usx2y->as04);
+	return err;
+}
+
+int usx2y_in04_init(struct usx2ydev *usx2y)
+{
+	int err;
+
+	if (WARN_ON(usx2y->in04_urb))
+		return -EBUSY;
+
+	usx2y->in04_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!usx2y->in04_urb) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	usx2y->in04_buf = kzalloc(USX2Y_IN04_SIZE, GFP_KERNEL);
+	if (!usx2y->in04_buf) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	init_waitqueue_head(&usx2y->in04_wait_queue);
+	usb_fill_int_urb(usx2y->in04_urb, usx2y->dev, usb_rcvintpipe(usx2y->dev, 0x4),
+			 usx2y->in04_buf, USX2Y_IN04_SIZE,
+			 i_usx2y_in04_int, usx2y,
+			 10);
+	if (usb_urb_ep_type_check(usx2y->in04_urb)) {
+		err = -EINVAL;
+		goto error;
+	}
+	return usb_submit_urb(usx2y->in04_urb, GFP_KERNEL);
+
+ error:
+	kfree(usx2y->in04_buf);
+	usb_free_urb(usx2y->in04_urb);
+	usx2y->in04_buf = NULL;
+	usx2y->in04_urb = NULL;
+	return err;
+}
+
+static void usx2y_unlinkseq(struct snd_usx2y_async_seq *s)
+{
+	int	i;
+
+	for (i = 0; i < URBS_ASYNC_SEQ; ++i) {
+		if (!s->urb[i])
+			continue;
+		usb_kill_urb(s->urb[i]);
+		usb_free_urb(s->urb[i]);
+		s->urb[i] = NULL;
+	}
+	kfree(s->buffer);
+	s->buffer = NULL;
+}
+
+static const struct usb_device_id snd_usx2y_usb_id_table[] = {
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	0x1604,
+		.idProduct =	USB_ID_US428
+	},
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	0x1604,
+		.idProduct =	USB_ID_US122
+	},
+	{
+		.match_flags =	USB_DEVICE_ID_MATCH_DEVICE,
+		.idVendor =	0x1604,
+		.idProduct =	USB_ID_US224
+	},
+	{ /* terminator */ }
+};
+MODULE_DEVICE_TABLE(usb, snd_usx2y_usb_id_table);
+
+static int usx2y_create_card(struct usb_device *device,
+			     struct usb_interface *intf,
+			     struct snd_card **cardp)
+{
+	int		dev;
+	struct snd_card *card;
+	int err;
+
+	for (dev = 0; dev < SNDRV_CARDS; ++dev)
+		if (enable[dev] && !snd_usx2y_card_used[dev])
+			break;
+	if (dev >= SNDRV_CARDS)
+		return -ENODEV;
+	err = snd_card_new(&intf->dev, index[dev], id[dev], THIS_MODULE,
+			   sizeof(struct usx2ydev), &card);
+	if (err < 0)
+		return err;
+	snd_usx2y_card_used[usx2y(card)->card_index = dev] = 1;
+	card->private_free = snd_usx2y_card_private_free;
+	usx2y(card)->dev = device;
+	init_waitqueue_head(&usx2y(card)->prepare_wait_queue);
+	init_waitqueue_head(&usx2y(card)->us428ctls_wait_queue_head);
+	mutex_init(&usx2y(card)->pcm_mutex);
+	INIT_LIST_HEAD(&usx2y(card)->midi_list);
+	strscpy(card->driver, "USB "NAME_ALLCAPS"");
+	sprintf(card->shortname, "TASCAM "NAME_ALLCAPS"");
+	sprintf(card->longname, "%s (%x:%x if %d at %03d/%03d)",
+		card->shortname,
+		le16_to_cpu(device->descriptor.idVendor),
+		le16_to_cpu(device->descriptor.idProduct),
+		0,//us428(card)->usbmidi.ifnum,
+		usx2y(card)->dev->bus->busnum, usx2y(card)->dev->devnum);
+	*cardp = card;
+	return 0;
+}
+
+static void snd_usx2y_card_private_free(struct snd_card *card)
+{
+	struct usx2ydev *usx2y = usx2y(card);
+
+	kfree(usx2y->in04_buf);
+	usb_free_urb(usx2y->in04_urb);
+	if (usx2y->us428ctls_sharedmem)
+		free_pages_exact(usx2y->us428ctls_sharedmem,
+				 US428_SHAREDMEM_PAGES);
+	if (usx2y->card_index >= 0 && usx2y->card_index < SNDRV_CARDS)
+		snd_usx2y_card_used[usx2y->card_index] = 0;
+}
+
+static void snd_usx2y_disconnect(struct usb_interface *intf)
+{
+	struct snd_card *card;
+	struct usx2ydev *usx2y;
+	struct list_head *p;
+
+	card = usb_get_intfdata(intf);
+	if (!card)
+		return;
+	usx2y = usx2y(card);
+	usx2y->chip_status = USX2Y_STAT_CHIP_HUP;
+	usx2y_unlinkseq(&usx2y->as04);
+	usb_kill_urb(usx2y->in04_urb);
+	snd_card_disconnect(card);
+
+	/* release the midi resources */
+	list_for_each(p, &usx2y->midi_list) {
+		snd_usbmidi_disconnect(p);
+	}
+	if (usx2y->us428ctls_sharedmem)
+		wake_up(&usx2y->us428ctls_wait_queue_head);
+	snd_card_free_when_closed(card);
+}
+
+static int snd_usx2y_probe(struct usb_interface *intf,
+			   const struct usb_device_id *id)
+{
+	struct usb_device *device = interface_to_usbdev(intf);
+	struct snd_card *card;
+	int err;
+
+#ifdef USX2Y_NRPACKS_VARIABLE
+	if (nrpacks < 0 || nrpacks > USX2Y_NRPACKS_MAX)
+		return -EINVAL;
+#endif
+
+	if (le16_to_cpu(device->descriptor.idVendor) != 0x1604 ||
+	    (le16_to_cpu(device->descriptor.idProduct) != USB_ID_US122 &&
+	     le16_to_cpu(device->descriptor.idProduct) != USB_ID_US224 &&
+	     le16_to_cpu(device->descriptor.idProduct) != USB_ID_US428))
+		return -EINVAL;
+
+	err = usx2y_create_card(device, intf, &card);
+	if (err < 0)
+		return err;
+	err = usx2y_hwdep_new(card, device);
+	if (err < 0)
+		goto error;
+	err = snd_card_register(card);
+	if (err < 0)
+		goto error;
+
+	dev_set_drvdata(&intf->dev, card);
+	return 0;
+
+ error:
+	snd_card_free(card);
+	return err;
+}
+
+static struct usb_driver snd_usx2y_usb_driver = {
+	.name =		"snd-usb-usx2y",
+	.probe =	snd_usx2y_probe,
+	.disconnect =	snd_usx2y_disconnect,
+	.id_table =	snd_usx2y_usb_id_table,
+};
+module_usb_driver(snd_usx2y_usb_driver);
diff --git a/sound/usb/usx2y/usbusx2y.h b/sound/usb/usx2y/usbusx2y.h
new file mode 100644
index 000000000..7b6deed17
--- /dev/null
+++ b/sound/usb/usx2y/usbusx2y.h
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef USBUSX2Y_H
+#define USBUSX2Y_H
+#include "../usbaudio.h"
+#include "../midi.h"
+#include "usbus428ctldefs.h"
+
+#define USX2Y_IN04_SIZE	sizeof(struct us428_ctls)
+
+#define NRURBS	        2
+
+/* Default value used for nr of packs per urb.
+ * 1 to 4 have been tested ok on uhci.
+ * To use 3 on ohci, you'd need a patch:
+ * look for "0000425-linux-2.6.9-rc4-mm1_ohci-hcd.patch.gz" on
+ * "https://bugtrack.alsa-project.org/alsa-bug/bug_view_page.php?bug_id=0000425"
+ *
+ * 1, 2 and 4 work out of the box on ohci, if I recall correctly.
+ * Bigger is safer operation, smaller gives lower latencies.
+ */
+#define USX2Y_NRPACKS 4
+
+#define USX2Y_NRPACKS_MAX 1024
+
+/* If your system works ok with this module's parameter
+ * nrpacks set to 1, you might as well comment
+ * this define out, and thereby produce smaller, faster code.
+ * You'd also set USX2Y_NRPACKS to 1 then.
+ */
+#define USX2Y_NRPACKS_VARIABLE 1
+
+#ifdef USX2Y_NRPACKS_VARIABLE
+extern int nrpacks;
+#define nr_of_packs() nrpacks
+#else
+#define nr_of_packs() USX2Y_NRPACKS
+#endif
+
+#define URBS_ASYNC_SEQ 10
+#define URB_DATA_LEN_ASYNC_SEQ 32
+struct snd_usx2y_async_seq {
+	struct urb	*urb[URBS_ASYNC_SEQ];
+	char		*buffer;
+};
+
+struct snd_usx2y_urb_seq {
+	int	submitted;
+	int	len;
+	struct urb	*urb[] __counted_by(len);
+};
+
+#include "usx2yhwdeppcm.h"
+
+struct usx2ydev {
+	struct usb_device	*dev;
+	int			card_index;
+	int			stride;
+	struct urb		*in04_urb;
+	void			*in04_buf;
+	char			in04_last[USX2Y_IN04_SIZE];
+	unsigned int		in04_int_calls;
+	struct snd_usx2y_urb_seq	*us04;
+	wait_queue_head_t	in04_wait_queue;
+	struct snd_usx2y_async_seq	as04;
+	unsigned int		rate,
+				format;
+	int			chip_status;
+	struct mutex		pcm_mutex;
+	struct us428ctls_sharedmem	*us428ctls_sharedmem;
+	int			wait_iso_frame;
+	wait_queue_head_t	us428ctls_wait_queue_head;
+	struct snd_usx2y_hwdep_pcm_shm	*hwdep_pcm_shm;
+	struct snd_usx2y_substream	*subs[4];
+	struct snd_usx2y_substream	* volatile  prepare_subs;
+	wait_queue_head_t	prepare_wait_queue;
+	struct list_head	midi_list;
+	int			pcm_devs;
+};
+
+
+struct snd_usx2y_substream {
+	struct usx2ydev	*usx2y;
+	struct snd_pcm_substream *pcm_substream;
+
+	int			endpoint;
+	unsigned int		maxpacksize;		/* max packet size in bytes */
+
+	atomic_t		state;
+#define STATE_STOPPED	0
+#define STATE_STARTING1 1
+#define STATE_STARTING2 2
+#define STATE_STARTING3 3
+#define STATE_PREPARED	4
+#define STATE_PRERUNNING  6
+#define STATE_RUNNING	8
+
+	int			hwptr;			/* free frame position in the buffer (only for playback) */
+	int			hwptr_done;		/* processed frame position in the buffer */
+	int			transfer_done;		/* processed frames since last period update */
+
+	struct urb		*urb[NRURBS];	/* data urb table */
+	struct urb		*completed_urb;
+	char			*tmpbuf;			/* temporary buffer for playback */
+};
+
+
+#define usx2y(c) ((struct usx2ydev *)(c)->private_data)
+
+int usx2y_audio_create(struct snd_card *card);
+
+int usx2y_async_seq04_init(struct usx2ydev *usx2y);
+int usx2y_in04_init(struct usx2ydev *usx2y);
+
+#define NAME_ALLCAPS "US-X2Y"
+
+#endif
diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c
new file mode 100644
index 000000000..a3a0bc136
--- /dev/null
+++ b/sound/usb/usx2y/usbusx2yaudio.c
@@ -0,0 +1,1007 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   US-X2Y AUDIO
+ *   Copyright (c) 2002-2004 by Karsten Wiese
+ *
+ *   based on
+ *
+ *   (Tentative) USB Audio Driver for ALSA
+ *
+ *   Main and PCM part
+ *
+ *   Copyright (c) 2002 by Takashi Iwai <tiwai@suse.de>
+ *
+ *   Many codes borrowed from audio.c by
+ *	    Alan Cox (alan@lxorguk.ukuu.org.uk)
+ *	    Thomas Sailer (sailer@ife.ee.ethz.ch)
+ */
+
+
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/moduleparam.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include "usx2y.h"
+#include "usbusx2y.h"
+
+static int usx2y_urb_capt_retire(struct snd_usx2y_substream *subs)
+{
+	struct urb	*urb = subs->completed_urb;
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+	unsigned char	*cp;
+	int		i, len, lens = 0, hwptr_done = subs->hwptr_done;
+	int		cnt, blen;
+	struct usx2ydev	*usx2y = subs->usx2y;
+
+	for (i = 0; i < nr_of_packs(); i++) {
+		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
+		if (urb->iso_frame_desc[i].status) { /* active? hmm, skip this */
+			dev_err(&usx2y->dev->dev,
+				"%s: active frame status %i. Most probably some hardware problem.\n",
+				__func__,
+				urb->iso_frame_desc[i].status);
+			return urb->iso_frame_desc[i].status;
+		}
+		len = urb->iso_frame_desc[i].actual_length / usx2y->stride;
+		if (!len) {
+			dev_dbg(&usx2y->dev->dev, "%s: 0 == len ERROR!\n", __func__);
+			continue;
+		}
+
+		/* copy a data chunk */
+		if ((hwptr_done + len) > runtime->buffer_size) {
+			cnt = runtime->buffer_size - hwptr_done;
+			blen = cnt * usx2y->stride;
+			memcpy(runtime->dma_area + hwptr_done * usx2y->stride, cp, blen);
+			memcpy(runtime->dma_area, cp + blen, len * usx2y->stride - blen);
+		} else {
+			memcpy(runtime->dma_area + hwptr_done * usx2y->stride, cp,
+			       len * usx2y->stride);
+		}
+		lens += len;
+		hwptr_done += len;
+		if (hwptr_done >= runtime->buffer_size)
+			hwptr_done -= runtime->buffer_size;
+	}
+
+	subs->hwptr_done = hwptr_done;
+	subs->transfer_done += lens;
+	/* update the pointer, call callback if necessary */
+	if (subs->transfer_done >= runtime->period_size) {
+		subs->transfer_done -= runtime->period_size;
+		snd_pcm_period_elapsed(subs->pcm_substream);
+	}
+	return 0;
+}
+
+/*
+ * prepare urb for playback data pipe
+ *
+ * we copy the data directly from the pcm buffer.
+ * the current position to be copied is held in hwptr field.
+ * since a urb can handle only a single linear buffer, if the total
+ * transferred area overflows the buffer boundary, we cannot send
+ * it directly from the buffer.  thus the data is once copied to
+ * a temporary buffer and urb points to that.
+ */
+static int usx2y_urb_play_prepare(struct snd_usx2y_substream *subs,
+				  struct urb *cap_urb,
+				  struct urb *urb)
+{
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+	int count, counts, pack, len;
+
+	count = 0;
+	for (pack = 0; pack <  nr_of_packs(); pack++) {
+		/* calculate the size of a packet */
+		counts = cap_urb->iso_frame_desc[pack].actual_length / usx2y->stride;
+		count += counts;
+		if (counts < 43 || counts > 50) {
+			dev_err(&usx2y->dev->dev, "%s: should not be here with counts=%i\n",
+				__func__, counts);
+			return -EPIPE;
+		}
+		/* set up descriptor */
+		urb->iso_frame_desc[pack].offset = pack ?
+			urb->iso_frame_desc[pack - 1].offset +
+			urb->iso_frame_desc[pack - 1].length :
+			0;
+		urb->iso_frame_desc[pack].length = cap_urb->iso_frame_desc[pack].actual_length;
+	}
+	if (atomic_read(&subs->state) >= STATE_PRERUNNING) {
+		if (subs->hwptr + count > runtime->buffer_size) {
+			/* err, the transferred area goes over buffer boundary.
+			 * copy the data to the temp buffer.
+			 */
+			len = runtime->buffer_size - subs->hwptr;
+			urb->transfer_buffer = subs->tmpbuf;
+			memcpy(subs->tmpbuf, runtime->dma_area +
+			       subs->hwptr * usx2y->stride, len * usx2y->stride);
+			memcpy(subs->tmpbuf + len * usx2y->stride,
+			       runtime->dma_area, (count - len) * usx2y->stride);
+			subs->hwptr += count;
+			subs->hwptr -= runtime->buffer_size;
+		} else {
+			/* set the buffer pointer */
+			urb->transfer_buffer = runtime->dma_area + subs->hwptr * usx2y->stride;
+			subs->hwptr += count;
+			if (subs->hwptr >= runtime->buffer_size)
+				subs->hwptr -= runtime->buffer_size;
+		}
+	} else {
+		urb->transfer_buffer = subs->tmpbuf;
+	}
+	urb->transfer_buffer_length = count * usx2y->stride;
+	return 0;
+}
+
+/*
+ * process after playback data complete
+ *
+ * update the current position and call callback if a period is processed.
+ */
+static void usx2y_urb_play_retire(struct snd_usx2y_substream *subs, struct urb *urb)
+{
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+	int		len = urb->actual_length / subs->usx2y->stride;
+
+	subs->transfer_done += len;
+	subs->hwptr_done +=  len;
+	if (subs->hwptr_done >= runtime->buffer_size)
+		subs->hwptr_done -= runtime->buffer_size;
+	if (subs->transfer_done >= runtime->period_size) {
+		subs->transfer_done -= runtime->period_size;
+		snd_pcm_period_elapsed(subs->pcm_substream);
+	}
+}
+
+static int usx2y_urb_submit(struct snd_usx2y_substream *subs, struct urb *urb, int frame)
+{
+	int err;
+
+	if (!urb)
+		return -ENODEV;
+	urb->start_frame = frame + NRURBS * nr_of_packs();  // let hcd do rollover sanity checks
+	urb->dev = subs->usx2y->dev; /* we need to set this at each time */
+	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (err < 0) {
+		dev_err(&urb->dev->dev, "%s: usb_submit_urb() returned %i\n",
+			__func__, err);
+		return err;
+	}
+	return 0;
+}
+
+static int usx2y_usbframe_complete(struct snd_usx2y_substream *capsubs,
+				   struct snd_usx2y_substream *playbacksubs,
+				   int frame)
+{
+	int err, state;
+	struct urb *urb = playbacksubs->completed_urb;
+
+	state = atomic_read(&playbacksubs->state);
+	if (urb) {
+		if (state == STATE_RUNNING)
+			usx2y_urb_play_retire(playbacksubs, urb);
+		else if (state >= STATE_PRERUNNING)
+			atomic_inc(&playbacksubs->state);
+	} else {
+		switch (state) {
+		case STATE_STARTING1:
+			urb = playbacksubs->urb[0];
+			atomic_inc(&playbacksubs->state);
+			break;
+		case STATE_STARTING2:
+			urb = playbacksubs->urb[1];
+			atomic_inc(&playbacksubs->state);
+			break;
+		}
+	}
+	if (urb) {
+		err = usx2y_urb_play_prepare(playbacksubs, capsubs->completed_urb, urb);
+		if (err)
+			return err;
+		err = usx2y_urb_submit(playbacksubs, urb, frame);
+		if (err)
+			return err;
+	}
+
+	playbacksubs->completed_urb = NULL;
+
+	state = atomic_read(&capsubs->state);
+	if (state >= STATE_PREPARED) {
+		if (state == STATE_RUNNING) {
+			err = usx2y_urb_capt_retire(capsubs);
+			if (err)
+				return err;
+		} else if (state >= STATE_PRERUNNING) {
+			atomic_inc(&capsubs->state);
+		}
+		err = usx2y_urb_submit(capsubs, capsubs->completed_urb, frame);
+		if (err)
+			return err;
+	}
+	capsubs->completed_urb = NULL;
+	return 0;
+}
+
+static void usx2y_clients_stop(struct usx2ydev *usx2y)
+{
+	struct snd_usx2y_substream *subs;
+	struct urb *urb;
+	int s, u;
+
+	for (s = 0; s < 4; s++) {
+		subs = usx2y->subs[s];
+		if (subs) {
+			dev_dbg(&usx2y->dev->dev, "%s: %i %p state=%i\n",
+				__func__, s, subs, atomic_read(&subs->state));
+			atomic_set(&subs->state, STATE_STOPPED);
+		}
+	}
+	for (s = 0; s < 4; s++) {
+		subs = usx2y->subs[s];
+		if (subs) {
+			if (atomic_read(&subs->state) >= STATE_PRERUNNING)
+				snd_pcm_stop_xrun(subs->pcm_substream);
+			for (u = 0; u < NRURBS; u++) {
+				urb = subs->urb[u];
+				if (urb)
+					dev_dbg(&usx2y->dev->dev,
+						"%s: %i status=%i start_frame=%i\n",
+						__func__, u, urb->status, urb->start_frame);
+			}
+		}
+	}
+	usx2y->prepare_subs = NULL;
+	wake_up(&usx2y->prepare_wait_queue);
+}
+
+static void usx2y_error_urb_status(struct usx2ydev *usx2y,
+				   struct snd_usx2y_substream *subs, struct urb *urb)
+{
+	dev_err(&usx2y->dev->dev, "%s: ep=%i stalled with status=%i\n",
+		__func__, subs->endpoint, urb->status);
+	urb->status = 0;
+	usx2y_clients_stop(usx2y);
+}
+
+static void i_usx2y_urb_complete(struct urb *urb)
+{
+	struct snd_usx2y_substream *subs = urb->context;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct snd_usx2y_substream *capsubs, *playbacksubs;
+
+	if (unlikely(atomic_read(&subs->state) < STATE_PREPARED)) {
+		dev_dbg(&usx2y->dev->dev,
+			"%s: hcd_frame=%i ep=%i%s status=%i start_frame=%i\n",
+			__func__,
+			usb_get_current_frame_number(usx2y->dev),
+			subs->endpoint, usb_pipein(urb->pipe) ? "in" : "out",
+			urb->status, urb->start_frame);
+		return;
+	}
+	if (unlikely(urb->status)) {
+		usx2y_error_urb_status(usx2y, subs, urb);
+		return;
+	}
+
+	subs->completed_urb = urb;
+
+	capsubs = usx2y->subs[SNDRV_PCM_STREAM_CAPTURE];
+	playbacksubs = usx2y->subs[SNDRV_PCM_STREAM_PLAYBACK];
+
+	if (capsubs->completed_urb &&
+	    atomic_read(&capsubs->state) >= STATE_PREPARED &&
+	    (playbacksubs->completed_urb ||
+	     atomic_read(&playbacksubs->state) < STATE_PREPARED)) {
+		if (!usx2y_usbframe_complete(capsubs, playbacksubs, urb->start_frame)) {
+			usx2y->wait_iso_frame += nr_of_packs();
+		} else {
+			usx2y_clients_stop(usx2y);
+		}
+	}
+}
+
+static void usx2y_urbs_set_complete(struct usx2ydev *usx2y,
+				    void (*complete)(struct urb *))
+{
+	struct snd_usx2y_substream *subs;
+	struct urb *urb;
+	int s, u;
+
+	for (s = 0; s < 4; s++) {
+		subs = usx2y->subs[s];
+		if (subs) {
+			for (u = 0; u < NRURBS; u++) {
+				urb = subs->urb[u];
+				if (urb)
+					urb->complete = complete;
+			}
+		}
+	}
+}
+
+static void usx2y_subs_startup_finish(struct usx2ydev *usx2y)
+{
+	usx2y_urbs_set_complete(usx2y, i_usx2y_urb_complete);
+	usx2y->prepare_subs = NULL;
+}
+
+static void i_usx2y_subs_startup(struct urb *urb)
+{
+	struct snd_usx2y_substream *subs = urb->context;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct snd_usx2y_substream *prepare_subs = usx2y->prepare_subs;
+
+	if (prepare_subs) {
+		if (urb->start_frame == prepare_subs->urb[0]->start_frame) {
+			usx2y_subs_startup_finish(usx2y);
+			atomic_inc(&prepare_subs->state);
+			wake_up(&usx2y->prepare_wait_queue);
+		}
+	}
+
+	i_usx2y_urb_complete(urb);
+}
+
+static void usx2y_subs_prepare(struct snd_usx2y_substream *subs)
+{
+	dev_dbg(&subs->usx2y->dev->dev,
+		"%s(%p) ep=%i urb0=%p urb1=%p\n",
+		__func__, subs, subs->endpoint, subs->urb[0], subs->urb[1]);
+	/* reset the pointer */
+	subs->hwptr = 0;
+	subs->hwptr_done = 0;
+	subs->transfer_done = 0;
+}
+
+static void usx2y_urb_release(struct urb **urb, int free_tb)
+{
+	if (*urb) {
+		usb_kill_urb(*urb);
+		if (free_tb)
+			kfree((*urb)->transfer_buffer);
+		usb_free_urb(*urb);
+		*urb = NULL;
+	}
+}
+
+/*
+ * release a substreams urbs
+ */
+static void usx2y_urbs_release(struct snd_usx2y_substream *subs)
+{
+	int i;
+
+	dev_dbg(&subs->usx2y->dev->dev, "%s %i\n", __func__, subs->endpoint);
+	for (i = 0; i < NRURBS; i++)
+		usx2y_urb_release(subs->urb + i,
+				  subs != subs->usx2y->subs[SNDRV_PCM_STREAM_PLAYBACK]);
+
+	kfree(subs->tmpbuf);
+	subs->tmpbuf = NULL;
+}
+
+/*
+ * initialize a substream's urbs
+ */
+static int usx2y_urbs_allocate(struct snd_usx2y_substream *subs)
+{
+	int i;
+	unsigned int pipe;
+	int is_playback = subs == subs->usx2y->subs[SNDRV_PCM_STREAM_PLAYBACK];
+	struct usb_device *dev = subs->usx2y->dev;
+	struct urb **purb;
+
+	pipe = is_playback ? usb_sndisocpipe(dev, subs->endpoint) :
+			usb_rcvisocpipe(dev, subs->endpoint);
+	subs->maxpacksize = usb_maxpacket(dev, pipe);
+	if (!subs->maxpacksize)
+		return -EINVAL;
+
+	if (is_playback && !subs->tmpbuf) {	/* allocate a temporary buffer for playback */
+		subs->tmpbuf = kcalloc(nr_of_packs(), subs->maxpacksize, GFP_KERNEL);
+		if (!subs->tmpbuf)
+			return -ENOMEM;
+	}
+	/* allocate and initialize data urbs */
+	for (i = 0; i < NRURBS; i++) {
+		purb = subs->urb + i;
+		if (*purb) {
+			usb_kill_urb(*purb);
+			continue;
+		}
+		*purb = usb_alloc_urb(nr_of_packs(), GFP_KERNEL);
+		if (!*purb) {
+			usx2y_urbs_release(subs);
+			return -ENOMEM;
+		}
+		if (!is_playback && !(*purb)->transfer_buffer) {
+			/* allocate a capture buffer per urb */
+			(*purb)->transfer_buffer =
+				kmalloc_array(subs->maxpacksize,
+					      nr_of_packs(), GFP_KERNEL);
+			if (!(*purb)->transfer_buffer) {
+				usx2y_urbs_release(subs);
+				return -ENOMEM;
+			}
+		}
+		(*purb)->dev = dev;
+		(*purb)->pipe = pipe;
+		(*purb)->number_of_packets = nr_of_packs();
+		(*purb)->context = subs;
+		(*purb)->interval = 1;
+		(*purb)->complete = i_usx2y_subs_startup;
+	}
+	return 0;
+}
+
+static void usx2y_subs_startup(struct snd_usx2y_substream *subs)
+{
+	struct usx2ydev *usx2y = subs->usx2y;
+
+	usx2y->prepare_subs = subs;
+	subs->urb[0]->start_frame = -1;
+	wmb();
+	usx2y_urbs_set_complete(usx2y, i_usx2y_subs_startup);
+}
+
+static int usx2y_urbs_start(struct snd_usx2y_substream *subs)
+{
+	int i, err;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct urb *urb;
+	unsigned long pack;
+
+	err = usx2y_urbs_allocate(subs);
+	if (err < 0)
+		return err;
+	subs->completed_urb = NULL;
+	for (i = 0; i < 4; i++) {
+		struct snd_usx2y_substream *subs = usx2y->subs[i];
+
+		if (subs && atomic_read(&subs->state) >= STATE_PREPARED)
+			goto start;
+	}
+
+ start:
+	usx2y_subs_startup(subs);
+	for (i = 0; i < NRURBS; i++) {
+		urb = subs->urb[i];
+		if (usb_pipein(urb->pipe)) {
+			if (!i)
+				atomic_set(&subs->state, STATE_STARTING3);
+			urb->dev = usx2y->dev;
+			for (pack = 0; pack < nr_of_packs(); pack++) {
+				urb->iso_frame_desc[pack].offset = subs->maxpacksize * pack;
+				urb->iso_frame_desc[pack].length = subs->maxpacksize;
+			}
+			urb->transfer_buffer_length = subs->maxpacksize * nr_of_packs();
+			err = usb_submit_urb(urb, GFP_ATOMIC);
+			if (err < 0) {
+				dev_err(&urb->dev->dev, "%s: cannot submit datapipe for urb %d, err = %d\n",
+					__func__, i, err);
+				err = -EPIPE;
+				goto cleanup;
+			} else {
+				if (!i)
+					usx2y->wait_iso_frame = urb->start_frame;
+			}
+			urb->transfer_flags = 0;
+		} else {
+			atomic_set(&subs->state, STATE_STARTING1);
+			break;
+		}
+	}
+	err = 0;
+	wait_event(usx2y->prepare_wait_queue, !usx2y->prepare_subs);
+	if (atomic_read(&subs->state) != STATE_PREPARED)
+		err = -EPIPE;
+
+ cleanup:
+	if (err) {
+		usx2y_subs_startup_finish(usx2y);
+		usx2y_clients_stop(usx2y);	// something is completely wrong > stop everything
+	}
+	return err;
+}
+
+/*
+ * return the current pcm pointer.  just return the hwptr_done value.
+ */
+static snd_pcm_uframes_t snd_usx2y_pcm_pointer(struct snd_pcm_substream *substream)
+{
+	struct snd_usx2y_substream *subs = substream->runtime->private_data;
+
+	return subs->hwptr_done;
+}
+
+/*
+ * start/stop substream
+ */
+static int snd_usx2y_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_usx2y_substream *subs = substream->runtime->private_data;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		dev_dbg(&subs->usx2y->dev->dev, "%s(START)\n", __func__);
+		if (atomic_read(&subs->state) == STATE_PREPARED &&
+		    atomic_read(&subs->usx2y->subs[SNDRV_PCM_STREAM_CAPTURE]->state) >= STATE_PREPARED) {
+			atomic_set(&subs->state, STATE_PRERUNNING);
+		} else {
+			return -EPIPE;
+		}
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+		dev_dbg(&subs->usx2y->dev->dev, "%s(STOP)\n", __func__);
+		if (atomic_read(&subs->state) >= STATE_PRERUNNING)
+			atomic_set(&subs->state, STATE_PREPARED);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/*
+ * allocate a buffer, setup samplerate
+ *
+ * so far we use a physically linear buffer although packetize transfer
+ * doesn't need a continuous area.
+ * if sg buffer is supported on the later version of alsa, we'll follow
+ * that.
+ */
+struct s_c2 {
+	char c1, c2;
+};
+
+static const struct s_c2 setrate_44100[] = {
+	{ 0x14, 0x08},	// this line sets 44100, well actually a little less
+	{ 0x18, 0x40},	// only tascam / frontier design knows the further lines .......
+	{ 0x18, 0x42},
+	{ 0x18, 0x45},
+	{ 0x18, 0x46},
+	{ 0x18, 0x48},
+	{ 0x18, 0x4A},
+	{ 0x18, 0x4C},
+	{ 0x18, 0x4E},
+	{ 0x18, 0x50},
+	{ 0x18, 0x52},
+	{ 0x18, 0x54},
+	{ 0x18, 0x56},
+	{ 0x18, 0x58},
+	{ 0x18, 0x5A},
+	{ 0x18, 0x5C},
+	{ 0x18, 0x5E},
+	{ 0x18, 0x60},
+	{ 0x18, 0x62},
+	{ 0x18, 0x64},
+	{ 0x18, 0x66},
+	{ 0x18, 0x68},
+	{ 0x18, 0x6A},
+	{ 0x18, 0x6C},
+	{ 0x18, 0x6E},
+	{ 0x18, 0x70},
+	{ 0x18, 0x72},
+	{ 0x18, 0x74},
+	{ 0x18, 0x76},
+	{ 0x18, 0x78},
+	{ 0x18, 0x7A},
+	{ 0x18, 0x7C},
+	{ 0x18, 0x7E}
+};
+
+static const struct s_c2 setrate_48000[] = {
+	{ 0x14, 0x09},	// this line sets 48000, well actually a little less
+	{ 0x18, 0x40},	// only tascam / frontier design knows the further lines .......
+	{ 0x18, 0x42},
+	{ 0x18, 0x45},
+	{ 0x18, 0x46},
+	{ 0x18, 0x48},
+	{ 0x18, 0x4A},
+	{ 0x18, 0x4C},
+	{ 0x18, 0x4E},
+	{ 0x18, 0x50},
+	{ 0x18, 0x52},
+	{ 0x18, 0x54},
+	{ 0x18, 0x56},
+	{ 0x18, 0x58},
+	{ 0x18, 0x5A},
+	{ 0x18, 0x5C},
+	{ 0x18, 0x5E},
+	{ 0x18, 0x60},
+	{ 0x18, 0x62},
+	{ 0x18, 0x64},
+	{ 0x18, 0x66},
+	{ 0x18, 0x68},
+	{ 0x18, 0x6A},
+	{ 0x18, 0x6C},
+	{ 0x18, 0x6E},
+	{ 0x18, 0x70},
+	{ 0x18, 0x73},
+	{ 0x18, 0x74},
+	{ 0x18, 0x76},
+	{ 0x18, 0x78},
+	{ 0x18, 0x7A},
+	{ 0x18, 0x7C},
+	{ 0x18, 0x7E}
+};
+
+#define NOOF_SETRATE_URBS ARRAY_SIZE(setrate_48000)
+
+static void i_usx2y_04int(struct urb *urb)
+{
+	struct usx2ydev *usx2y = urb->context;
+
+	if (urb->status)
+		dev_err(&urb->dev->dev, "%s() urb->status=%i\n",
+			__func__, urb->status);
+	if (!--usx2y->us04->len)
+		wake_up(&usx2y->in04_wait_queue);
+}
+
+static int usx2y_rate_set(struct usx2ydev *usx2y, int rate)
+{
+	int err = 0, i;
+	struct snd_usx2y_urb_seq *us = NULL;
+	int *usbdata = NULL;
+	const struct s_c2 *ra = rate == 48000 ? setrate_48000 : setrate_44100;
+	struct urb *urb;
+
+	if (usx2y->rate != rate) {
+		us = kzalloc_flex(*us, urb, NOOF_SETRATE_URBS);
+		if (!us) {
+			err = -ENOMEM;
+			goto cleanup;
+		}
+		us->len = NOOF_SETRATE_URBS;
+		usbdata = kmalloc_objs(int, NOOF_SETRATE_URBS);
+		if (!usbdata) {
+			err = -ENOMEM;
+			goto cleanup;
+		}
+		for (i = 0; i < NOOF_SETRATE_URBS; ++i) {
+			us->urb[i] = usb_alloc_urb(0, GFP_KERNEL);
+			if (!us->urb[i]) {
+				err = -ENOMEM;
+				goto cleanup;
+			}
+			((char *)(usbdata + i))[0] = ra[i].c1;
+			((char *)(usbdata + i))[1] = ra[i].c2;
+			usb_fill_bulk_urb(us->urb[i], usx2y->dev, usb_sndbulkpipe(usx2y->dev, 4),
+					  usbdata + i, 2, i_usx2y_04int, usx2y);
+		}
+		err = usb_urb_ep_type_check(us->urb[0]);
+		if (err < 0)
+			goto cleanup;
+		us->submitted =	0;
+		usx2y->us04 =	us;
+		wait_event_timeout(usx2y->in04_wait_queue, !us->len, HZ);
+		usx2y->us04 =	NULL;
+		if (us->len)
+			err = -ENODEV;
+	cleanup:
+		if (us) {
+			us->submitted =	2*NOOF_SETRATE_URBS;
+			for (i = 0; i < NOOF_SETRATE_URBS; ++i) {
+				urb = us->urb[i];
+				if (!urb)
+					continue;
+				if (urb->status) {
+					if (!err)
+						err = -ENODEV;
+					usb_kill_urb(urb);
+				}
+				usb_free_urb(urb);
+			}
+			usx2y->us04 = NULL;
+			kfree(usbdata);
+			kfree(us);
+			if (!err)
+				usx2y->rate = rate;
+		}
+	}
+
+	return err;
+}
+
+static int usx2y_format_set(struct usx2ydev *usx2y, snd_pcm_format_t format)
+{
+	int alternate, err;
+	struct list_head *p;
+
+	if (format == SNDRV_PCM_FORMAT_S24_3LE) {
+		alternate = 2;
+		usx2y->stride = 6;
+	} else {
+		alternate = 1;
+		usx2y->stride = 4;
+	}
+	list_for_each(p, &usx2y->midi_list) {
+		snd_usbmidi_input_stop(p);
+	}
+	usb_kill_urb(usx2y->in04_urb);
+	err = usb_set_interface(usx2y->dev, 0, alternate);
+	if (err) {
+		dev_err(&usx2y->dev->dev, "%s: usb_set_interface error\n",
+			__func__);
+		return err;
+	}
+	usx2y->in04_urb->dev = usx2y->dev;
+	err = usb_submit_urb(usx2y->in04_urb, GFP_KERNEL);
+	list_for_each(p, &usx2y->midi_list) {
+		snd_usbmidi_input_start(p);
+	}
+	usx2y->format = format;
+	usx2y->rate = 0;
+	return err;
+}
+
+
+static int snd_usx2y_pcm_hw_params(struct snd_pcm_substream *substream,
+				   struct snd_pcm_hw_params *hw_params)
+{
+	unsigned int		rate = params_rate(hw_params);
+	snd_pcm_format_t	format = params_format(hw_params);
+	struct snd_card *card = substream->pstr->pcm->card;
+	struct usx2ydev	*dev = usx2y(card);
+	struct snd_usx2y_substream *subs;
+	struct snd_pcm_substream *test_substream;
+	int i;
+
+	guard(mutex)(&usx2y(card)->pcm_mutex);
+	dev_dbg(&dev->dev->dev, "%s(%p, %p)\n", __func__, substream, hw_params);
+	/* all pcm substreams off one usx2y have to operate at the same
+	 * rate & format
+	 */
+	for (i = 0; i < dev->pcm_devs * 2; i++) {
+		subs = dev->subs[i];
+		if (!subs)
+			continue;
+		test_substream = subs->pcm_substream;
+		if (!test_substream || test_substream == substream ||
+		    !test_substream->runtime)
+			continue;
+		if ((test_substream->runtime->format &&
+		     test_substream->runtime->format != format) ||
+		    (test_substream->runtime->rate &&
+		     test_substream->runtime->rate != rate)) {
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * free the buffer
+ */
+static int snd_usx2y_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usx2y_substream *subs = runtime->private_data;
+	struct snd_usx2y_substream *cap_subs, *playback_subs;
+
+	guard(mutex)(&subs->usx2y->pcm_mutex);
+	dev_dbg(&subs->usx2y->dev->dev, "%s(%p)\n", __func__, substream);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		cap_subs = subs->usx2y->subs[SNDRV_PCM_STREAM_CAPTURE];
+		atomic_set(&subs->state, STATE_STOPPED);
+		usx2y_urbs_release(subs);
+		if (!cap_subs->pcm_substream ||
+		    !cap_subs->pcm_substream->runtime ||
+		    cap_subs->pcm_substream->runtime->state < SNDRV_PCM_STATE_PREPARED) {
+			atomic_set(&cap_subs->state, STATE_STOPPED);
+			usx2y_urbs_release(cap_subs);
+		}
+	} else {
+		playback_subs = subs->usx2y->subs[SNDRV_PCM_STREAM_PLAYBACK];
+		if (atomic_read(&playback_subs->state) < STATE_PREPARED) {
+			atomic_set(&subs->state, STATE_STOPPED);
+			usx2y_urbs_release(subs);
+		}
+	}
+	return 0;
+}
+
+/*
+ * prepare callback
+ *
+ * set format and initialize urbs
+ */
+static int snd_usx2y_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usx2y_substream *subs = runtime->private_data;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct snd_usx2y_substream *capsubs = subs->usx2y->subs[SNDRV_PCM_STREAM_CAPTURE];
+	int err = 0;
+
+	dev_dbg(&usx2y->dev->dev, "%s(%p)\n", __func__, substream);
+
+	guard(mutex)(&usx2y->pcm_mutex);
+	usx2y_subs_prepare(subs);
+	// Start hardware streams
+	// SyncStream first....
+	if (atomic_read(&capsubs->state) < STATE_PREPARED) {
+		if (usx2y->format != runtime->format) {
+			err = usx2y_format_set(usx2y, runtime->format);
+			if (err < 0)
+				return err;
+		}
+		if (usx2y->rate != runtime->rate) {
+			err = usx2y_rate_set(usx2y, runtime->rate);
+			if (err < 0)
+				return err;
+		}
+		dev_dbg(&usx2y->dev->dev, "%s: starting capture pipe for %s\n",
+			__func__, subs == capsubs ? "self" : "playpipe");
+		err = usx2y_urbs_start(capsubs);
+		if (err < 0)
+			return err;
+	}
+
+	if (subs != capsubs && atomic_read(&subs->state) < STATE_PREPARED)
+		err = usx2y_urbs_start(subs);
+
+	return err;
+}
+
+static const struct snd_pcm_hardware snd_usx2y_2c = {
+	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
+				 SNDRV_PCM_INFO_BLOCK_TRANSFER |
+				 SNDRV_PCM_INFO_MMAP_VALID |
+				 SNDRV_PCM_INFO_BATCH),
+	.formats =                 SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_3LE,
+	.rates =                   SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
+	.rate_min =                44100,
+	.rate_max =                48000,
+	.channels_min =            2,
+	.channels_max =            2,
+	.buffer_bytes_max =	(2*128*1024),
+	.period_bytes_min =	64,
+	.period_bytes_max =	(128*1024),
+	.periods_min =		2,
+	.periods_max =		1024,
+	.fifo_size =              0
+};
+
+static int snd_usx2y_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_usx2y_substream	*subs =
+		((struct snd_usx2y_substream **)
+		 snd_pcm_substream_chip(substream))[substream->stream];
+	struct snd_pcm_runtime	*runtime = substream->runtime;
+
+	if (subs->usx2y->chip_status & USX2Y_STAT_CHIP_MMAP_PCM_URBS)
+		return -EBUSY;
+
+	runtime->hw = snd_usx2y_2c;
+	runtime->private_data = subs;
+	subs->pcm_substream = substream;
+	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME, 1000, 200000);
+	return 0;
+}
+
+static int snd_usx2y_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usx2y_substream *subs = runtime->private_data;
+
+	subs->pcm_substream = NULL;
+
+	return 0;
+}
+
+static const struct snd_pcm_ops snd_usx2y_pcm_ops = {
+	.open =		snd_usx2y_pcm_open,
+	.close =	snd_usx2y_pcm_close,
+	.hw_params =	snd_usx2y_pcm_hw_params,
+	.hw_free =	snd_usx2y_pcm_hw_free,
+	.prepare =	snd_usx2y_pcm_prepare,
+	.trigger =	snd_usx2y_pcm_trigger,
+	.pointer =	snd_usx2y_pcm_pointer,
+};
+
+/*
+ * free a usb stream instance
+ */
+static void usx2y_audio_stream_free(struct snd_usx2y_substream **usx2y_substream)
+{
+	int stream;
+
+	for_each_pcm_streams(stream) {
+		kfree(usx2y_substream[stream]);
+		usx2y_substream[stream] = NULL;
+	}
+}
+
+static void snd_usx2y_pcm_private_free(struct snd_pcm *pcm)
+{
+	struct snd_usx2y_substream **usx2y_stream = pcm->private_data;
+
+	if (usx2y_stream)
+		usx2y_audio_stream_free(usx2y_stream);
+}
+
+static int usx2y_audio_stream_new(struct snd_card *card, int playback_endpoint, int capture_endpoint)
+{
+	struct snd_pcm *pcm;
+	int err, i;
+	struct snd_usx2y_substream **usx2y_substream =
+		usx2y(card)->subs + 2 * usx2y(card)->pcm_devs;
+
+	for (i = playback_endpoint ? SNDRV_PCM_STREAM_PLAYBACK : SNDRV_PCM_STREAM_CAPTURE;
+	     i <= SNDRV_PCM_STREAM_CAPTURE; ++i) {
+		usx2y_substream[i] = kzalloc_obj(struct snd_usx2y_substream);
+		if (!usx2y_substream[i])
+			return -ENOMEM;
+
+		usx2y_substream[i]->usx2y = usx2y(card);
+	}
+
+	if (playback_endpoint)
+		usx2y_substream[SNDRV_PCM_STREAM_PLAYBACK]->endpoint = playback_endpoint;
+	usx2y_substream[SNDRV_PCM_STREAM_CAPTURE]->endpoint = capture_endpoint;
+
+	err = snd_pcm_new(card, NAME_ALLCAPS" Audio", usx2y(card)->pcm_devs,
+			  playback_endpoint ? 1 : 0, 1,
+			  &pcm);
+	if (err < 0) {
+		usx2y_audio_stream_free(usx2y_substream);
+		return err;
+	}
+
+	if (playback_endpoint)
+		snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_usx2y_pcm_ops);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_usx2y_pcm_ops);
+
+	pcm->private_data = usx2y_substream;
+	pcm->private_free = snd_usx2y_pcm_private_free;
+	pcm->info_flags = 0;
+
+	sprintf(pcm->name, NAME_ALLCAPS" Audio #%d", usx2y(card)->pcm_devs);
+
+	if (playback_endpoint) {
+		snd_pcm_set_managed_buffer(pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream,
+					   SNDRV_DMA_TYPE_CONTINUOUS,
+					   NULL,
+					   64*1024, 128*1024);
+	}
+
+	snd_pcm_set_managed_buffer(pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream,
+				   SNDRV_DMA_TYPE_CONTINUOUS,
+				   NULL,
+				   64*1024, 128*1024);
+	usx2y(card)->pcm_devs++;
+
+	return 0;
+}
+
+/*
+ * create a chip instance and set its names.
+ */
+int usx2y_audio_create(struct snd_card *card)
+{
+	int err;
+
+	err = usx2y_audio_stream_new(card, 0xA, 0x8);
+	if (err < 0)
+		return err;
+	if (le16_to_cpu(usx2y(card)->dev->descriptor.idProduct) == USB_ID_US428) {
+		err = usx2y_audio_stream_new(card, 0, 0xA);
+		if (err < 0)
+			return err;
+	}
+	if (le16_to_cpu(usx2y(card)->dev->descriptor.idProduct) != USB_ID_US122)
+		err = usx2y_rate_set(usx2y(card), 44100);	// Lets us428 recognize output-volume settings, disturbs us122.
+	return err;
+}
diff --git a/sound/usb/usx2y/usx2y.h b/sound/usb/usx2y/usx2y.h
new file mode 100644
index 000000000..780071ddd
--- /dev/null
+++ b/sound/usb/usx2y/usx2y.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Driver for Tascam US-X2Y USB soundcards
+ *
+ * Copyright (c) 2003 by Karsten Wiese <annabellesgarden@yahoo.de>
+ */
+
+#ifndef __SOUND_USX2Y_COMMON_H
+#define __SOUND_USX2Y_COMMON_H
+
+
+#define USX2Y_DRIVER_VERSION	0x0100	/* 0.1.0 */
+
+
+/* hwdep id string */
+#define SND_USX2Y_LOADER_ID		"USX2Y Loader"
+#define SND_USX2Y_USBPCM_ID		"USX2Y USBPCM"
+
+/* hardware type */
+enum {
+	USX2Y_TYPE_122,
+	USX2Y_TYPE_224,
+	USX2Y_TYPE_428,
+	USX2Y_TYPE_NUMS
+};
+
+#define USB_ID_US122 0x8007
+#define USB_ID_US224 0x8005
+#define USB_ID_US428 0x8001
+
+/* chip status */
+enum {
+	USX2Y_STAT_CHIP_INIT	=	(1 << 0),	/* all operational */
+	USX2Y_STAT_CHIP_MMAP_PCM_URBS = (1 << 1),	/* pcm transport over mmaped urbs */
+	USX2Y_STAT_CHIP_HUP	=	(1 << 31),	/* all operational */
+};
+
+#endif /* __SOUND_USX2Y_COMMON_H */
diff --git a/sound/usb/usx2y/usx2yhwdeppcm.c b/sound/usb/usx2y/usx2yhwdeppcm.c
new file mode 100644
index 000000000..f1d5b4b79
--- /dev/null
+++ b/sound/usb/usx2y/usx2yhwdeppcm.c
@@ -0,0 +1,774 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+/* USX2Y "rawusb" aka hwdep_pcm implementation
+
+ Its usb's unableness to atomically handle power of 2 period sized data chuncs
+ at standard samplerates,
+ what led to this part of the usx2y module:
+ It provides the alsa kernel half of the usx2y-alsa-jack driver pair.
+ The pair uses a hardware dependent alsa-device for mmaped pcm transport.
+ Advantage achieved:
+         The usb_hc moves pcm data from/into memory via DMA.
+         That memory is mmaped by jack's usx2y driver.
+         Jack's usx2y driver is the first/last to read/write pcm data.
+         Read/write is a combination of power of 2 period shaping and
+         float/int conversation.
+         Compared to mainline alsa/jack we leave out power of 2 period shaping inside
+         snd-usb-usx2y which needs memcpy() and additional buffers.
+         As a side effect possible unwanted pcm-data coruption resulting of
+         standard alsa's snd-usb-usx2y period shaping scheme falls away.
+         Result is sane jack operation at buffering schemes down to 128frames,
+         2 periods.
+         plain usx2y alsa mode is able to achieve 64frames, 4periods, but only at the
+         cost of easier triggered i.e. aeolus xruns (128 or 256frames,
+         2periods works but is useless cause of crackling).
+
+ This is a first "proof of concept" implementation.
+ Later, functionalities should migrate to more appropriate places:
+ Userland:
+ - The jackd could mmap its float-pcm buffers directly from alsa-lib.
+ - alsa-lib could provide power of 2 period sized shaping combined with int/float
+   conversation.
+   Currently the usx2y jack driver provides above 2 services.
+ Kernel:
+ - rawusb dma pcm buffer transport should go to snd-usb-lib, so also snd-usb-audio
+   devices can use it.
+   Currently rawusb dma pcm buffer transport (this file) is only available to snd-usb-usx2y.
+*/
+
+#include <linux/delay.h>
+#include <linux/gfp.h>
+#include "usbusx2yaudio.c"
+
+#if defined(USX2Y_NRPACKS_VARIABLE) || USX2Y_NRPACKS == 1
+
+#include <sound/hwdep.h>
+
+static int usx2y_usbpcm_urb_capt_retire(struct snd_usx2y_substream *subs)
+{
+	struct urb	*urb = subs->completed_urb;
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+	int		i, lens = 0, hwptr_done = subs->hwptr_done;
+	struct usx2ydev	*usx2y = subs->usx2y;
+	int head;
+
+	if (usx2y->hwdep_pcm_shm->capture_iso_start < 0) { //FIXME
+		head = usx2y->hwdep_pcm_shm->captured_iso_head + 1;
+		if (head >= ARRAY_SIZE(usx2y->hwdep_pcm_shm->captured_iso))
+			head = 0;
+		usx2y->hwdep_pcm_shm->capture_iso_start = head;
+		dev_dbg(&usx2y->dev->dev, "cap start %i\n", head);
+	}
+	for (i = 0; i < nr_of_packs(); i++) {
+		if (urb->iso_frame_desc[i].status) { /* active? hmm, skip this */
+			dev_err(&usx2y->dev->dev,
+				"active frame status %i. Most probably some hardware problem.\n",
+				urb->iso_frame_desc[i].status);
+			return urb->iso_frame_desc[i].status;
+		}
+		lens += urb->iso_frame_desc[i].actual_length / usx2y->stride;
+	}
+	hwptr_done += lens;
+	if (hwptr_done >= runtime->buffer_size)
+		hwptr_done -= runtime->buffer_size;
+	subs->hwptr_done = hwptr_done;
+	subs->transfer_done += lens;
+	/* update the pointer, call callback if necessary */
+	if (subs->transfer_done >= runtime->period_size) {
+		subs->transfer_done -= runtime->period_size;
+		snd_pcm_period_elapsed(subs->pcm_substream);
+	}
+	return 0;
+}
+
+static int usx2y_iso_frames_per_buffer(struct snd_pcm_runtime *runtime,
+					      struct usx2ydev *usx2y)
+{
+	return (runtime->buffer_size * 1000) / usx2y->rate + 1;	//FIXME: so far only correct period_size == 2^x ?
+}
+
+/*
+ * prepare urb for playback data pipe
+ *
+ * we copy the data directly from the pcm buffer.
+ * the current position to be copied is held in hwptr field.
+ * since a urb can handle only a single linear buffer, if the total
+ * transferred area overflows the buffer boundary, we cannot send
+ * it directly from the buffer.  thus the data is once copied to
+ * a temporary buffer and urb points to that.
+ */
+static int usx2y_hwdep_urb_play_prepare(struct snd_usx2y_substream *subs,
+					struct urb *urb)
+{
+	int count, counts, pack;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct snd_usx2y_hwdep_pcm_shm *shm = usx2y->hwdep_pcm_shm;
+	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+
+	if (shm->playback_iso_start < 0) {
+		shm->playback_iso_start = shm->captured_iso_head -
+			usx2y_iso_frames_per_buffer(runtime, usx2y);
+		if (shm->playback_iso_start < 0)
+			shm->playback_iso_start += ARRAY_SIZE(shm->captured_iso);
+		shm->playback_iso_head = shm->playback_iso_start;
+	}
+
+	count = 0;
+	for (pack = 0; pack < nr_of_packs(); pack++) {
+		/* calculate the size of a packet */
+		counts = shm->captured_iso[shm->playback_iso_head].length / usx2y->stride;
+		if (counts < 43 || counts > 50) {
+			dev_err(&usx2y->dev->dev, "should not be here with counts=%i\n", counts);
+			return -EPIPE;
+		}
+		/* set up descriptor */
+		urb->iso_frame_desc[pack].offset = shm->captured_iso[shm->playback_iso_head].offset;
+		urb->iso_frame_desc[pack].length = shm->captured_iso[shm->playback_iso_head].length;
+		if (atomic_read(&subs->state) != STATE_RUNNING)
+			memset((char *)urb->transfer_buffer + urb->iso_frame_desc[pack].offset, 0,
+			       urb->iso_frame_desc[pack].length);
+		if (++shm->playback_iso_head >= ARRAY_SIZE(shm->captured_iso))
+			shm->playback_iso_head = 0;
+		count += counts;
+	}
+	urb->transfer_buffer_length = count * usx2y->stride;
+	return 0;
+}
+
+static void usx2y_usbpcm_urb_capt_iso_advance(struct snd_usx2y_substream *subs,
+					      struct urb *urb)
+{
+	struct usb_iso_packet_descriptor *desc;
+	struct snd_usx2y_hwdep_pcm_shm *shm;
+	int pack, head;
+
+	for (pack = 0; pack < nr_of_packs(); ++pack) {
+		desc = urb->iso_frame_desc + pack;
+		if (subs) {
+			shm = subs->usx2y->hwdep_pcm_shm;
+			head = shm->captured_iso_head + 1;
+			if (head >= ARRAY_SIZE(shm->captured_iso))
+				head = 0;
+			shm->captured_iso[head].frame = urb->start_frame + pack;
+			shm->captured_iso[head].offset = desc->offset;
+			shm->captured_iso[head].length = desc->actual_length;
+			shm->captured_iso_head = head;
+			shm->captured_iso_frames++;
+		}
+		desc->offset += desc->length * NRURBS * nr_of_packs();
+		if (desc->offset + desc->length >= SSS)
+			desc->offset -= (SSS - desc->length);
+	}
+}
+
+static int usx2y_usbpcm_usbframe_complete(struct snd_usx2y_substream *capsubs,
+					  struct snd_usx2y_substream *capsubs2,
+					  struct snd_usx2y_substream *playbacksubs,
+					  int frame)
+{
+	int err, state;
+	struct urb *urb = playbacksubs->completed_urb;
+
+	state = atomic_read(&playbacksubs->state);
+	if (urb) {
+		if (state == STATE_RUNNING)
+			usx2y_urb_play_retire(playbacksubs, urb);
+		else if (state >= STATE_PRERUNNING)
+			atomic_inc(&playbacksubs->state);
+	} else {
+		switch (state) {
+		case STATE_STARTING1:
+			urb = playbacksubs->urb[0];
+			atomic_inc(&playbacksubs->state);
+			break;
+		case STATE_STARTING2:
+			urb = playbacksubs->urb[1];
+			atomic_inc(&playbacksubs->state);
+			break;
+		}
+	}
+	if (urb) {
+		err = usx2y_hwdep_urb_play_prepare(playbacksubs, urb);
+		if (err)
+			return err;
+		err = usx2y_hwdep_urb_play_prepare(playbacksubs, urb);
+		if (err)
+			return err;
+	}
+
+	playbacksubs->completed_urb = NULL;
+
+	state = atomic_read(&capsubs->state);
+	if (state >= STATE_PREPARED) {
+		if (state == STATE_RUNNING) {
+			err = usx2y_usbpcm_urb_capt_retire(capsubs);
+			if (err)
+				return err;
+		} else if (state >= STATE_PRERUNNING) {
+			atomic_inc(&capsubs->state);
+		}
+		usx2y_usbpcm_urb_capt_iso_advance(capsubs, capsubs->completed_urb);
+		if (capsubs2)
+			usx2y_usbpcm_urb_capt_iso_advance(NULL, capsubs2->completed_urb);
+		err = usx2y_urb_submit(capsubs, capsubs->completed_urb, frame);
+		if (err)
+			return err;
+		if (capsubs2) {
+			err = usx2y_urb_submit(capsubs2, capsubs2->completed_urb, frame);
+			if (err)
+				return err;
+		}
+	}
+	capsubs->completed_urb = NULL;
+	if (capsubs2)
+		capsubs2->completed_urb = NULL;
+	return 0;
+}
+
+static void i_usx2y_usbpcm_urb_complete(struct urb *urb)
+{
+	struct snd_usx2y_substream *subs = urb->context;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct snd_usx2y_substream *capsubs, *capsubs2, *playbacksubs;
+
+	if (unlikely(atomic_read(&subs->state) < STATE_PREPARED)) {
+		dev_dbg(&usx2y->dev->dev,
+			"hcd_frame=%i ep=%i%s status=%i start_frame=%i\n",
+			usb_get_current_frame_number(usx2y->dev),
+			subs->endpoint, usb_pipein(urb->pipe) ? "in" : "out",
+			urb->status, urb->start_frame);
+		return;
+	}
+	if (unlikely(urb->status)) {
+		usx2y_error_urb_status(usx2y, subs, urb);
+		return;
+	}
+
+	subs->completed_urb = urb;
+	capsubs = usx2y->subs[SNDRV_PCM_STREAM_CAPTURE];
+	capsubs2 = usx2y->subs[SNDRV_PCM_STREAM_CAPTURE + 2];
+	playbacksubs = usx2y->subs[SNDRV_PCM_STREAM_PLAYBACK];
+	if (capsubs->completed_urb && atomic_read(&capsubs->state) >= STATE_PREPARED &&
+	    (!capsubs2 || capsubs2->completed_urb) &&
+	    (playbacksubs->completed_urb || atomic_read(&playbacksubs->state) < STATE_PREPARED)) {
+		if (!usx2y_usbpcm_usbframe_complete(capsubs, capsubs2, playbacksubs, urb->start_frame)) {
+			usx2y->wait_iso_frame += nr_of_packs();
+		} else {
+			usx2y_clients_stop(usx2y);
+		}
+	}
+}
+
+static void usx2y_hwdep_urb_release(struct urb **urb)
+{
+	usb_kill_urb(*urb);
+	usb_free_urb(*urb);
+	*urb = NULL;
+}
+
+/*
+ * release a substream
+ */
+static void usx2y_usbpcm_urbs_release(struct snd_usx2y_substream *subs)
+{
+	int i;
+
+	dev_dbg(&subs->usx2y->dev->dev,
+		"snd_usx2y_urbs_release() %i\n", subs->endpoint);
+	for (i = 0; i < NRURBS; i++)
+		usx2y_hwdep_urb_release(subs->urb + i);
+}
+
+static void usx2y_usbpcm_subs_startup_finish(struct usx2ydev *usx2y)
+{
+	usx2y_urbs_set_complete(usx2y, i_usx2y_usbpcm_urb_complete);
+	usx2y->prepare_subs = NULL;
+}
+
+static void i_usx2y_usbpcm_subs_startup(struct urb *urb)
+{
+	struct snd_usx2y_substream *subs = urb->context;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct snd_usx2y_substream *prepare_subs = usx2y->prepare_subs;
+	struct snd_usx2y_substream *cap_subs2;
+
+	if (prepare_subs &&
+	    urb->start_frame == prepare_subs->urb[0]->start_frame) {
+		atomic_inc(&prepare_subs->state);
+		if (prepare_subs == usx2y->subs[SNDRV_PCM_STREAM_CAPTURE]) {
+			cap_subs2 = usx2y->subs[SNDRV_PCM_STREAM_CAPTURE + 2];
+			if (cap_subs2)
+				atomic_inc(&cap_subs2->state);
+		}
+		usx2y_usbpcm_subs_startup_finish(usx2y);
+		wake_up(&usx2y->prepare_wait_queue);
+	}
+
+	i_usx2y_usbpcm_urb_complete(urb);
+}
+
+/*
+ * initialize a substream's urbs
+ */
+static int usx2y_usbpcm_urbs_allocate(struct snd_usx2y_substream *subs)
+{
+	int i;
+	unsigned int pipe;
+	int is_playback = subs == subs->usx2y->subs[SNDRV_PCM_STREAM_PLAYBACK];
+	struct usb_device *dev = subs->usx2y->dev;
+	struct urb **purb;
+
+	pipe = is_playback ? usb_sndisocpipe(dev, subs->endpoint) :
+			usb_rcvisocpipe(dev, subs->endpoint);
+	subs->maxpacksize = usb_maxpacket(dev, pipe);
+	if (!subs->maxpacksize)
+		return -EINVAL;
+
+	/* allocate and initialize data urbs */
+	for (i = 0; i < NRURBS; i++) {
+		purb = subs->urb + i;
+		if (*purb) {
+			usb_kill_urb(*purb);
+			continue;
+		}
+		*purb = usb_alloc_urb(nr_of_packs(), GFP_KERNEL);
+		if (!*purb) {
+			usx2y_usbpcm_urbs_release(subs);
+			return -ENOMEM;
+		}
+		(*purb)->transfer_buffer = is_playback ?
+			subs->usx2y->hwdep_pcm_shm->playback : (
+				subs->endpoint == 0x8 ?
+				subs->usx2y->hwdep_pcm_shm->capture0x8 :
+				subs->usx2y->hwdep_pcm_shm->capture0xA);
+
+		(*purb)->dev = dev;
+		(*purb)->pipe = pipe;
+		(*purb)->number_of_packets = nr_of_packs();
+		(*purb)->context = subs;
+		(*purb)->interval = 1;
+		(*purb)->complete = i_usx2y_usbpcm_subs_startup;
+	}
+	return 0;
+}
+
+/*
+ * free the buffer
+ */
+static int snd_usx2y_usbpcm_hw_free(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usx2y_substream *subs = runtime->private_data;
+	struct snd_usx2y_substream *cap_subs;
+	struct snd_usx2y_substream *playback_subs;
+	struct snd_usx2y_substream *cap_subs2;
+
+	guard(mutex)(&subs->usx2y->pcm_mutex);
+	dev_dbg(&subs->usx2y->dev->dev, "%s(%p)\n", __func__, substream);
+
+	cap_subs2 = subs->usx2y->subs[SNDRV_PCM_STREAM_CAPTURE + 2];
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		cap_subs = subs->usx2y->subs[SNDRV_PCM_STREAM_CAPTURE];
+		atomic_set(&subs->state, STATE_STOPPED);
+		usx2y_usbpcm_urbs_release(subs);
+		if (!cap_subs->pcm_substream ||
+		    !cap_subs->pcm_substream->runtime ||
+		    cap_subs->pcm_substream->runtime->state < SNDRV_PCM_STATE_PREPARED) {
+			atomic_set(&cap_subs->state, STATE_STOPPED);
+			if (cap_subs2)
+				atomic_set(&cap_subs2->state, STATE_STOPPED);
+			usx2y_usbpcm_urbs_release(cap_subs);
+			if (cap_subs2)
+				usx2y_usbpcm_urbs_release(cap_subs2);
+		}
+	} else {
+		playback_subs = subs->usx2y->subs[SNDRV_PCM_STREAM_PLAYBACK];
+		if (atomic_read(&playback_subs->state) < STATE_PREPARED) {
+			atomic_set(&subs->state, STATE_STOPPED);
+			if (cap_subs2)
+				atomic_set(&cap_subs2->state, STATE_STOPPED);
+			usx2y_usbpcm_urbs_release(subs);
+			if (cap_subs2)
+				usx2y_usbpcm_urbs_release(cap_subs2);
+		}
+	}
+	return 0;
+}
+
+static void usx2y_usbpcm_subs_startup(struct snd_usx2y_substream *subs)
+{
+	struct usx2ydev *usx2y = subs->usx2y;
+
+	usx2y->prepare_subs = subs;
+	subs->urb[0]->start_frame = -1;
+	smp_wmb();	// Make sure above modifications are seen by i_usx2y_subs_startup()
+	usx2y_urbs_set_complete(usx2y, i_usx2y_usbpcm_subs_startup);
+}
+
+static int usx2y_usbpcm_urbs_start(struct snd_usx2y_substream *subs)
+{
+	int	p, u, err, stream = subs->pcm_substream->stream;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct urb *urb;
+	unsigned long pack;
+
+	if (stream == SNDRV_PCM_STREAM_CAPTURE) {
+		usx2y->hwdep_pcm_shm->captured_iso_head = -1;
+		usx2y->hwdep_pcm_shm->captured_iso_frames = 0;
+	}
+
+	for (p = 0; 3 >= (stream + p); p += 2) {
+		struct snd_usx2y_substream *subs = usx2y->subs[stream + p];
+		if (subs) {
+			err = usx2y_usbpcm_urbs_allocate(subs);
+			if (err < 0)
+				return err;
+			subs->completed_urb = NULL;
+		}
+	}
+
+	for (p = 0; p < 4; p++) {
+		struct snd_usx2y_substream *subs = usx2y->subs[p];
+
+		if (subs && atomic_read(&subs->state) >= STATE_PREPARED)
+			goto start;
+	}
+
+ start:
+	usx2y_usbpcm_subs_startup(subs);
+	for (u = 0; u < NRURBS; u++) {
+		for (p = 0; 3 >= (stream + p); p += 2) {
+			struct snd_usx2y_substream *subs = usx2y->subs[stream + p];
+
+			if (!subs)
+				continue;
+			urb = subs->urb[u];
+			if (usb_pipein(urb->pipe)) {
+				if (!u)
+					atomic_set(&subs->state, STATE_STARTING3);
+				urb->dev = usx2y->dev;
+				for (pack = 0; pack < nr_of_packs(); pack++) {
+					urb->iso_frame_desc[pack].offset = subs->maxpacksize * (pack + u * nr_of_packs());
+					urb->iso_frame_desc[pack].length = subs->maxpacksize;
+				}
+				urb->transfer_buffer_length = subs->maxpacksize * nr_of_packs();
+				err = usb_submit_urb(urb, GFP_KERNEL);
+				if (err < 0) {
+					dev_err(&urb->dev->dev,
+						"cannot usb_submit_urb() for urb %d, err = %d\n",
+						u, err);
+					err = -EPIPE;
+					goto cleanup;
+				}  else {
+					if (!u)
+						usx2y->wait_iso_frame = urb->start_frame;
+				}
+				urb->transfer_flags = 0;
+			} else {
+				atomic_set(&subs->state, STATE_STARTING1);
+				break;
+			}
+		}
+	}
+	err = 0;
+	wait_event(usx2y->prepare_wait_queue, !usx2y->prepare_subs);
+	if (atomic_read(&subs->state) != STATE_PREPARED)
+		err = -EPIPE;
+
+ cleanup:
+	if (err) {
+		usx2y_subs_startup_finish(usx2y);	// Call it now
+		usx2y_clients_stop(usx2y);	// something is completely wrong > stop everything
+	}
+	return err;
+}
+
+#define USX2Y_HWDEP_PCM_PAGES	\
+	PAGE_ALIGN(sizeof(struct snd_usx2y_hwdep_pcm_shm))
+
+/*
+ * prepare callback
+ *
+ * set format and initialize urbs
+ */
+static int snd_usx2y_usbpcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usx2y_substream *subs = runtime->private_data;
+	struct usx2ydev *usx2y = subs->usx2y;
+	struct snd_usx2y_substream *capsubs = subs->usx2y->subs[SNDRV_PCM_STREAM_CAPTURE];
+	int err = 0;
+
+	dev_dbg(&usx2y->dev->dev, "snd_usx2y_pcm_prepare(%p)\n", substream);
+
+	guard(mutex)(&usx2y->pcm_mutex);
+
+	if (!usx2y->hwdep_pcm_shm) {
+		usx2y->hwdep_pcm_shm = alloc_pages_exact(USX2Y_HWDEP_PCM_PAGES,
+							 GFP_KERNEL);
+		if (!usx2y->hwdep_pcm_shm)
+			return -ENOMEM;
+		memset(usx2y->hwdep_pcm_shm, 0, USX2Y_HWDEP_PCM_PAGES);
+	}
+
+	usx2y_subs_prepare(subs);
+	// Start hardware streams
+	// SyncStream first....
+	if (atomic_read(&capsubs->state) < STATE_PREPARED) {
+		if (usx2y->format != runtime->format) {
+			err = usx2y_format_set(usx2y, runtime->format);
+			if (err < 0)
+				return err;
+		}
+		if (usx2y->rate != runtime->rate) {
+			err = usx2y_rate_set(usx2y, runtime->rate);
+			if (err < 0)
+				return err;
+		}
+		dev_dbg(&usx2y->dev->dev,
+			"starting capture pipe for %s\n", subs == capsubs ?
+			"self" : "playpipe");
+		err = usx2y_usbpcm_urbs_start(capsubs);
+		if (err < 0)
+			return err;
+	}
+
+	if (subs != capsubs) {
+		usx2y->hwdep_pcm_shm->playback_iso_start = -1;
+		if (atomic_read(&subs->state) < STATE_PREPARED) {
+			while (usx2y_iso_frames_per_buffer(runtime, usx2y) >
+			       usx2y->hwdep_pcm_shm->captured_iso_frames) {
+				dev_dbg(&usx2y->dev->dev,
+					"Wait: iso_frames_per_buffer=%i,captured_iso_frames=%i\n",
+					usx2y_iso_frames_per_buffer(runtime, usx2y),
+					usx2y->hwdep_pcm_shm->captured_iso_frames);
+				if (msleep_interruptible(10))
+					return -ERESTARTSYS;
+			}
+			err = usx2y_usbpcm_urbs_start(subs);
+			if (err < 0)
+				return err;
+		}
+		dev_dbg(&usx2y->dev->dev,
+			"Ready: iso_frames_per_buffer=%i,captured_iso_frames=%i\n",
+			usx2y_iso_frames_per_buffer(runtime, usx2y),
+			usx2y->hwdep_pcm_shm->captured_iso_frames);
+	} else {
+		usx2y->hwdep_pcm_shm->capture_iso_start = -1;
+	}
+
+	return err;
+}
+
+static const struct snd_pcm_hardware snd_usx2y_4c = {
+	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
+				 SNDRV_PCM_INFO_BLOCK_TRANSFER |
+				 SNDRV_PCM_INFO_MMAP_VALID),
+	.formats =                 SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_3LE,
+	.rates =                   SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
+	.rate_min =                44100,
+	.rate_max =                48000,
+	.channels_min =            2,
+	.channels_max =            4,
+	.buffer_bytes_max =	(2*128*1024),
+	.period_bytes_min =	64,
+	.period_bytes_max =	(128*1024),
+	.periods_min =		2,
+	.periods_max =		1024,
+	.fifo_size =              0
+};
+
+static int snd_usx2y_usbpcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_usx2y_substream	*subs =
+		((struct snd_usx2y_substream **)
+		 snd_pcm_substream_chip(substream))[substream->stream];
+	struct snd_pcm_runtime	*runtime = substream->runtime;
+
+	if (!(subs->usx2y->chip_status & USX2Y_STAT_CHIP_MMAP_PCM_URBS))
+		return -EBUSY;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		runtime->hw = snd_usx2y_2c;
+	else
+		runtime->hw = (subs->usx2y->subs[3] ? snd_usx2y_4c : snd_usx2y_2c);
+	runtime->private_data = subs;
+	subs->pcm_substream = substream;
+	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME, 1000, 200000);
+	return 0;
+}
+
+static int snd_usx2y_usbpcm_close(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_usx2y_substream *subs = runtime->private_data;
+
+	subs->pcm_substream = NULL;
+	return 0;
+}
+
+static const struct snd_pcm_ops snd_usx2y_usbpcm_ops = {
+	.open =		snd_usx2y_usbpcm_open,
+	.close =	snd_usx2y_usbpcm_close,
+	.hw_params =	snd_usx2y_pcm_hw_params,
+	.hw_free =	snd_usx2y_usbpcm_hw_free,
+	.prepare =	snd_usx2y_usbpcm_prepare,
+	.trigger =	snd_usx2y_pcm_trigger,
+	.pointer =	snd_usx2y_pcm_pointer,
+};
+
+static int usx2y_pcms_busy_check(struct snd_card *card)
+{
+	struct usx2ydev	*dev = usx2y(card);
+	struct snd_usx2y_substream *subs;
+	int i;
+
+	for (i = 0; i < dev->pcm_devs * 2; i++) {
+		subs = dev->subs[i];
+		if (subs && subs->pcm_substream &&
+		    SUBSTREAM_BUSY(subs->pcm_substream))
+			return -EBUSY;
+	}
+	return 0;
+}
+
+static int snd_usx2y_hwdep_pcm_open(struct snd_hwdep *hw, struct file *file)
+{
+	struct snd_card *card = hw->card;
+	int err;
+
+	guard(mutex)(&usx2y(card)->pcm_mutex);
+	err = usx2y_pcms_busy_check(card);
+	if (!err)
+		usx2y(card)->chip_status |= USX2Y_STAT_CHIP_MMAP_PCM_URBS;
+	return err;
+}
+
+static int snd_usx2y_hwdep_pcm_release(struct snd_hwdep *hw, struct file *file)
+{
+	struct snd_card *card = hw->card;
+	int err;
+
+	guard(mutex)(&usx2y(card)->pcm_mutex);
+	err = usx2y_pcms_busy_check(card);
+	if (!err)
+		usx2y(hw->card)->chip_status &= ~USX2Y_STAT_CHIP_MMAP_PCM_URBS;
+	return err;
+}
+
+static void snd_usx2y_hwdep_pcm_vm_open(struct vm_area_struct *area)
+{
+}
+
+static void snd_usx2y_hwdep_pcm_vm_close(struct vm_area_struct *area)
+{
+}
+
+static vm_fault_t snd_usx2y_hwdep_pcm_vm_fault(struct vm_fault *vmf)
+{
+	unsigned long offset;
+	void *vaddr;
+
+	offset = vmf->pgoff << PAGE_SHIFT;
+	if (offset >= USX2Y_HWDEP_PCM_PAGES)
+		return VM_FAULT_SIGBUS;
+	vaddr = (char *)((struct usx2ydev *)vmf->vma->vm_private_data)->hwdep_pcm_shm + offset;
+	vmf->page = virt_to_page(vaddr);
+	get_page(vmf->page);
+	return 0;
+}
+
+static const struct vm_operations_struct snd_usx2y_hwdep_pcm_vm_ops = {
+	.open = snd_usx2y_hwdep_pcm_vm_open,
+	.close = snd_usx2y_hwdep_pcm_vm_close,
+	.fault = snd_usx2y_hwdep_pcm_vm_fault,
+};
+
+static int snd_usx2y_hwdep_pcm_mmap(struct snd_hwdep *hw, struct file *filp, struct vm_area_struct *area)
+{
+	unsigned long	size = (unsigned long)(area->vm_end - area->vm_start);
+	struct usx2ydev	*usx2y = hw->private_data;
+
+	if (!(usx2y->chip_status & USX2Y_STAT_CHIP_INIT))
+		return -EBUSY;
+
+	/* if userspace tries to mmap beyond end of our buffer, fail */
+	if (size > USX2Y_HWDEP_PCM_PAGES) {
+		dev_dbg(hw->card->dev, "%s: %lu > %lu\n", __func__,
+			size, (unsigned long)USX2Y_HWDEP_PCM_PAGES);
+		return -EINVAL;
+	}
+
+	if (!usx2y->hwdep_pcm_shm)
+		return -ENODEV;
+
+	area->vm_ops = &snd_usx2y_hwdep_pcm_vm_ops;
+	vm_flags_set(area, VM_DONTEXPAND | VM_DONTDUMP);
+	area->vm_private_data = hw->private_data;
+	return 0;
+}
+
+static void snd_usx2y_hwdep_pcm_private_free(struct snd_hwdep *hwdep)
+{
+	struct usx2ydev *usx2y = hwdep->private_data;
+
+	if (usx2y->hwdep_pcm_shm)
+		free_pages_exact(usx2y->hwdep_pcm_shm, USX2Y_HWDEP_PCM_PAGES);
+}
+
+int usx2y_hwdep_pcm_new(struct snd_card *card)
+{
+	int err;
+	struct snd_hwdep *hw;
+	struct snd_pcm *pcm;
+	struct usb_device *dev = usx2y(card)->dev;
+
+	if (nr_of_packs() != 1)
+		return 0;
+
+	err = snd_hwdep_new(card, SND_USX2Y_USBPCM_ID, 1, &hw);
+	if (err < 0)
+		return err;
+
+	hw->iface = SNDRV_HWDEP_IFACE_USX2Y_PCM;
+	hw->private_data = usx2y(card);
+	hw->private_free = snd_usx2y_hwdep_pcm_private_free;
+	hw->ops.open = snd_usx2y_hwdep_pcm_open;
+	hw->ops.release = snd_usx2y_hwdep_pcm_release;
+	hw->ops.mmap = snd_usx2y_hwdep_pcm_mmap;
+	hw->exclusive = 1;
+	sprintf(hw->name, "/dev/bus/usb/%03d/%03d/hwdeppcm", dev->bus->busnum, dev->devnum);
+
+	err = snd_pcm_new(card, NAME_ALLCAPS" hwdep Audio", 2, 1, 1, &pcm);
+	if (err < 0)
+		return err;
+
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_usx2y_usbpcm_ops);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_usx2y_usbpcm_ops);
+
+	pcm->private_data = usx2y(card)->subs;
+	pcm->info_flags = 0;
+
+	sprintf(pcm->name, NAME_ALLCAPS" hwdep Audio");
+	snd_pcm_set_managed_buffer(pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream,
+				   SNDRV_DMA_TYPE_CONTINUOUS,
+				   NULL,
+				   64*1024, 128*1024);
+	snd_pcm_set_managed_buffer(pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream,
+				   SNDRV_DMA_TYPE_CONTINUOUS,
+				   NULL,
+				   64*1024, 128*1024);
+
+	return 0;
+}
+
+#else
+
+int usx2y_hwdep_pcm_new(struct snd_card *card)
+{
+	return 0;
+}
+
+#endif
diff --git a/sound/usb/usx2y/usx2yhwdeppcm.h b/sound/usb/usx2y/usx2yhwdeppcm.h
new file mode 100644
index 000000000..731b1c5a3
--- /dev/null
+++ b/sound/usb/usx2y/usx2yhwdeppcm.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#define MAXPACK 50
+#define MAXBUFFERMS 100
+#define MAXSTRIDE 3
+
+#define SSS (((MAXPACK*MAXBUFFERMS*MAXSTRIDE + 4096) / 4096) * 4096)
+struct snd_usx2y_hwdep_pcm_shm {
+	char playback[SSS];
+	char capture0x8[SSS];
+	char capture0xA[SSS];
+	volatile int playback_iso_head;
+	int playback_iso_start;
+	struct {
+		int	frame,
+			offset,
+			length;
+	} captured_iso[128];
+	volatile int captured_iso_head;
+	volatile unsigned captured_iso_frames;
+	int capture_iso_start;
+};
+
+int usx2y_hwdep_pcm_new(struct snd_card *card);
diff --git a/sound/usb/validate.c b/sound/usb/validate.c
new file mode 100644
index 000000000..f62b7cc04
--- /dev/null
+++ b/sound/usb/validate.c
@@ -0,0 +1,366 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// Validation of USB-audio class descriptors
+//
+
+#include <linux/init.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+#include <linux/usb/midi.h>
+#include "usbaudio.h"
+#include "helper.h"
+
+struct usb_desc_validator {
+	unsigned char protocol;
+	unsigned char type;
+	bool (*func)(const void *p, const struct usb_desc_validator *v);
+	size_t size;
+};
+
+#define UAC_VERSION_ALL		(unsigned char)(-1)
+
+/* UAC1 only */
+static bool validate_uac1_header(const void *p,
+				 const struct usb_desc_validator *v)
+{
+	const struct uac1_ac_header_descriptor *d = p;
+
+	return d->bLength >= sizeof(*d) &&
+		d->bLength >= sizeof(*d) + d->bInCollection;
+}
+
+/* for mixer unit; covering all UACs */
+static bool validate_mixer_unit(const void *p,
+				const struct usb_desc_validator *v)
+{
+	const struct uac_mixer_unit_descriptor *d = p;
+	size_t len;
+
+	if (d->bLength < sizeof(*d) || !d->bNrInPins)
+		return false;
+	len = sizeof(*d) + d->bNrInPins;
+	/* We can't determine the bitmap size only from this unit descriptor,
+	 * so just check with the remaining length.
+	 * The actual bitmap is checked at mixer unit parser.
+	 */
+	switch (v->protocol) {
+	case UAC_VERSION_1:
+	default:
+		len += 2 + 1; /* wChannelConfig, iChannelNames */
+		/* bmControls[n*m] */
+		len += 1; /* iMixer */
+		break;
+	case UAC_VERSION_2:
+		len += 4 + 1; /* bmChannelConfig, iChannelNames */
+		/* bmMixerControls[n*m] */
+		len += 1 + 1; /* bmControls, iMixer */
+		break;
+	case UAC_VERSION_3:
+		len += 2; /* wClusterDescrID */
+		/* bmMixerControls[n*m] */
+		break;
+	}
+	return d->bLength >= len;
+}
+
+/* both for processing and extension units; covering all UACs */
+static bool validate_processing_unit(const void *p,
+				     const struct usb_desc_validator *v)
+{
+	const struct uac_processing_unit_descriptor *d = p;
+	const unsigned char *hdr = p;
+	size_t len, m;
+
+	if (d->bLength < sizeof(*d))
+		return false;
+	len = sizeof(*d) + d->bNrInPins;
+	if (d->bLength < len)
+		return false;
+	switch (v->protocol) {
+	case UAC_VERSION_1:
+	default:
+		/* bNrChannels, wChannelConfig, iChannelNames */
+		len += 1 + 2 + 1;
+		if (d->bLength < len + 1) /* bControlSize */
+			return false;
+		m = hdr[len];
+		len += 1 + m + 1; /* bControlSize, bmControls, iProcessing */
+		break;
+	case UAC_VERSION_2:
+		/* bNrChannels, bmChannelConfig, iChannelNames */
+		len += 1 + 4 + 1;
+		if (v->type == UAC2_PROCESSING_UNIT_V2)
+			len += 2; /* bmControls -- 2 bytes for PU */
+		else
+			len += 1; /* bmControls -- 1 byte for EU */
+		len += 1; /* iProcessing */
+		break;
+	case UAC_VERSION_3:
+		/* wProcessingDescrStr, bmControls */
+		len += 2 + 4;
+		break;
+	}
+	if (d->bLength < len)
+		return false;
+
+	switch (v->protocol) {
+	case UAC_VERSION_1:
+	default:
+		if (v->type == UAC1_EXTENSION_UNIT)
+			return true; /* OK */
+		switch (le16_to_cpu(d->wProcessType)) {
+		case UAC_PROCESS_UP_DOWNMIX:
+		case UAC_PROCESS_DOLBY_PROLOGIC:
+			if (d->bLength < len + 1) /* bNrModes */
+				return false;
+			m = hdr[len];
+			len += 1 + m * 2; /* bNrModes, waModes(n) */
+			break;
+		default:
+			break;
+		}
+		break;
+	case UAC_VERSION_2:
+		if (v->type == UAC2_EXTENSION_UNIT_V2)
+			return true; /* OK */
+		switch (le16_to_cpu(d->wProcessType)) {
+		case UAC2_PROCESS_UP_DOWNMIX:
+		case UAC2_PROCESS_DOLBY_PROLOCIC: /* SiC! */
+			if (d->bLength < len + 1) /* bNrModes */
+				return false;
+			m = hdr[len];
+			len += 1 + m * 4; /* bNrModes, daModes(n) */
+			break;
+		default:
+			break;
+		}
+		break;
+	case UAC_VERSION_3:
+		if (v->type == UAC3_EXTENSION_UNIT) {
+			len += 2; /* wClusterDescrID */
+			break;
+		}
+		switch (le16_to_cpu(d->wProcessType)) {
+		case UAC3_PROCESS_UP_DOWNMIX:
+			if (d->bLength < len + 1) /* bNrModes */
+				return false;
+			m = hdr[len];
+			len += 1 + m * 2; /* bNrModes, waClusterDescrID(n) */
+			break;
+		case UAC3_PROCESS_MULTI_FUNCTION:
+			len += 2 + 4; /* wClusterDescrID, bmAlgorighms */
+			break;
+		default:
+			break;
+		}
+		break;
+	}
+	if (d->bLength < len)
+		return false;
+
+	return true;
+}
+
+/* both for selector and clock selector units; covering all UACs */
+static bool validate_selector_unit(const void *p,
+				   const struct usb_desc_validator *v)
+{
+	const struct uac_selector_unit_descriptor *d = p;
+	size_t len;
+
+	if (d->bLength < sizeof(*d))
+		return false;
+	len = sizeof(*d) + d->bNrInPins;
+	switch (v->protocol) {
+	case UAC_VERSION_1:
+	default:
+		len += 1; /* iSelector */
+		break;
+	case UAC_VERSION_2:
+		len += 1 + 1; /* bmControls, iSelector */
+		break;
+	case UAC_VERSION_3:
+		len += 4 + 2; /* bmControls, wSelectorDescrStr */
+		break;
+	}
+	return d->bLength >= len;
+}
+
+static bool validate_uac1_feature_unit(const void *p,
+				       const struct usb_desc_validator *v)
+{
+	const struct uac_feature_unit_descriptor *d = p;
+
+	if (d->bLength < sizeof(*d) || !d->bControlSize)
+		return false;
+	/* at least bmaControls(0) for master channel + iFeature */
+	return d->bLength >= sizeof(*d) + d->bControlSize + 1;
+}
+
+static bool validate_uac2_feature_unit(const void *p,
+				       const struct usb_desc_validator *v)
+{
+	const struct uac2_feature_unit_descriptor *d = p;
+
+	if (d->bLength < sizeof(*d))
+		return false;
+	/* at least bmaControls(0) for master channel + iFeature */
+	return d->bLength >= sizeof(*d) + 4 + 1;
+}
+
+static bool validate_uac3_feature_unit(const void *p,
+				       const struct usb_desc_validator *v)
+{
+	const struct uac3_feature_unit_descriptor *d = p;
+
+	if (d->bLength < sizeof(*d))
+		return false;
+	/* at least bmaControls(0) for master channel + wFeatureDescrStr */
+	return d->bLength >= sizeof(*d) + 4 + 2;
+}
+
+static bool validate_uac3_power_domain_unit(const void *p,
+					    const struct usb_desc_validator *v)
+{
+	const struct uac3_power_domain_descriptor *d = p;
+
+	if (d->bLength < sizeof(*d))
+		return false;
+	/* baEntities[] + wPDomainDescrStr */
+	return d->bLength >= sizeof(*d) + d->bNrEntities + 2;
+}
+
+static bool validate_midi_out_jack(const void *p,
+				   const struct usb_desc_validator *v)
+{
+	const struct usb_midi_out_jack_descriptor *d = p;
+
+	return d->bLength >= sizeof(*d) &&
+		d->bLength >= sizeof(*d) + d->bNrInputPins * 2;
+}
+
+#define FIXED(p, t, s) { .protocol = (p), .type = (t), .size = sizeof(s) }
+#define FUNC(p, t, f) { .protocol = (p), .type = (t), .func = (f) }
+
+static const struct usb_desc_validator audio_validators[] = {
+	/* UAC1 */
+	FUNC(UAC_VERSION_1, UAC_HEADER, validate_uac1_header),
+	FIXED(UAC_VERSION_1, UAC_INPUT_TERMINAL,
+	      struct uac_input_terminal_descriptor),
+	FIXED(UAC_VERSION_1, UAC_OUTPUT_TERMINAL,
+	      struct uac1_output_terminal_descriptor),
+	FUNC(UAC_VERSION_1, UAC_MIXER_UNIT, validate_mixer_unit),
+	FUNC(UAC_VERSION_1, UAC_SELECTOR_UNIT, validate_selector_unit),
+	FUNC(UAC_VERSION_1, UAC_FEATURE_UNIT, validate_uac1_feature_unit),
+	FUNC(UAC_VERSION_1, UAC1_PROCESSING_UNIT, validate_processing_unit),
+	FUNC(UAC_VERSION_1, UAC1_EXTENSION_UNIT, validate_processing_unit),
+
+	/* UAC2 */
+	FIXED(UAC_VERSION_2, UAC_HEADER, struct uac2_ac_header_descriptor),
+	FIXED(UAC_VERSION_2, UAC_INPUT_TERMINAL,
+	      struct uac2_input_terminal_descriptor),
+	FIXED(UAC_VERSION_2, UAC_OUTPUT_TERMINAL,
+	      struct uac2_output_terminal_descriptor),
+	FUNC(UAC_VERSION_2, UAC_MIXER_UNIT, validate_mixer_unit),
+	FUNC(UAC_VERSION_2, UAC_SELECTOR_UNIT, validate_selector_unit),
+	FUNC(UAC_VERSION_2, UAC_FEATURE_UNIT, validate_uac2_feature_unit),
+	/* just a stop-gap, it should be a proper function for the array
+	 * once if the unit is really parsed/used
+	 */
+	FIXED(UAC_VERSION_2, UAC2_EFFECT_UNIT,
+	      struct uac2_effect_unit_descriptor),
+	FUNC(UAC_VERSION_2, UAC2_PROCESSING_UNIT_V2, validate_processing_unit),
+	FUNC(UAC_VERSION_2, UAC2_EXTENSION_UNIT_V2, validate_processing_unit),
+	FIXED(UAC_VERSION_2, UAC2_CLOCK_SOURCE,
+	      struct uac_clock_source_descriptor),
+	FUNC(UAC_VERSION_2, UAC2_CLOCK_SELECTOR, validate_selector_unit),
+	FIXED(UAC_VERSION_2, UAC2_CLOCK_MULTIPLIER,
+	      struct uac_clock_multiplier_descriptor),
+	/* UAC_VERSION_2, UAC2_SAMPLE_RATE_CONVERTER: not implemented yet */
+
+	/* UAC3 */
+	FIXED(UAC_VERSION_3, UAC_HEADER, struct uac3_ac_header_descriptor),
+	FIXED(UAC_VERSION_3, UAC_INPUT_TERMINAL,
+	      struct uac3_input_terminal_descriptor),
+	FIXED(UAC_VERSION_3, UAC_OUTPUT_TERMINAL,
+	      struct uac3_output_terminal_descriptor),
+	/* UAC_VERSION_3, UAC3_EXTENDED_TERMINAL: not implemented yet */
+	FUNC(UAC_VERSION_3, UAC3_MIXER_UNIT, validate_mixer_unit),
+	FUNC(UAC_VERSION_3, UAC3_SELECTOR_UNIT, validate_selector_unit),
+	FUNC(UAC_VERSION_3, UAC3_FEATURE_UNIT, validate_uac3_feature_unit),
+	FIXED(UAC_VERSION_3, UAC3_EFFECT_UNIT,
+	      struct uac2_effect_unit_descriptor), /* sharing the same struct */
+	FUNC(UAC_VERSION_3, UAC3_PROCESSING_UNIT, validate_processing_unit),
+	FUNC(UAC_VERSION_3, UAC3_EXTENSION_UNIT, validate_processing_unit),
+	FIXED(UAC_VERSION_3, UAC3_CLOCK_SOURCE,
+	      struct uac3_clock_source_descriptor),
+	FUNC(UAC_VERSION_3, UAC3_CLOCK_SELECTOR, validate_selector_unit),
+	FIXED(UAC_VERSION_3, UAC3_CLOCK_MULTIPLIER,
+	      struct uac3_clock_multiplier_descriptor),
+	/* UAC_VERSION_3, UAC3_SAMPLE_RATE_CONVERTER: not implemented yet */
+	/* UAC_VERSION_3, UAC3_CONNECTORS: not implemented yet */
+	FUNC(UAC_VERSION_3, UAC3_POWER_DOMAIN, validate_uac3_power_domain_unit),
+	{ } /* terminator */
+};
+
+static const struct usb_desc_validator midi_validators[] = {
+	FIXED(UAC_VERSION_ALL, USB_MS_HEADER,
+	      struct usb_ms_header_descriptor),
+	FIXED(UAC_VERSION_ALL, USB_MS_MIDI_IN_JACK,
+	      struct usb_midi_in_jack_descriptor),
+	FUNC(UAC_VERSION_ALL, USB_MS_MIDI_OUT_JACK,
+	     validate_midi_out_jack),
+	{ } /* terminator */
+};
+
+
+/* Validate the given unit descriptor, return true if it's OK */
+static bool validate_desc(unsigned char *hdr, int protocol,
+			  const struct usb_desc_validator *v)
+{
+	if (hdr[1] != USB_DT_CS_INTERFACE)
+		return true; /* don't care */
+
+	for (; v->type; v++) {
+		if (v->type == hdr[2] &&
+		    (v->protocol == UAC_VERSION_ALL ||
+		     v->protocol == protocol)) {
+			if (v->func)
+				return v->func(hdr, v);
+			/* check for the fixed size */
+			return hdr[0] >= v->size;
+		}
+	}
+
+	return true; /* not matching, skip validation */
+}
+
+bool snd_usb_validate_audio_desc(void *p, int protocol)
+{
+	unsigned char *c = p;
+	bool valid;
+
+	valid = validate_desc(p, protocol, audio_validators);
+	if (!valid && snd_usb_skip_validation) {
+		print_hex_dump(KERN_ERR, "USB-audio: buggy audio desc: ",
+			       DUMP_PREFIX_NONE, 16, 1, c, c[0], true);
+		valid = true;
+	}
+	return valid;
+}
+
+bool snd_usb_validate_midi_desc(void *p)
+{
+	unsigned char *c = p;
+	bool valid;
+
+	valid = validate_desc(p, UAC_VERSION_1, midi_validators);
+	if (!valid && snd_usb_skip_validation) {
+		print_hex_dump(KERN_ERR, "USB-audio: buggy midi desc: ",
+			       DUMP_PREFIX_NONE, 16, 1, c, c[0], true);
+		valid = true;
+	}
+	return valid;
+}