Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

128 files changed, 71027 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..d3b7cab85
--- /dev/null
+++ b/sound/usb/6fire/comm.c
@@ -0,0 +1,202 @@
+// 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))
+{
+	usb_init_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;
+}
+
+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) {
+		kfree(rt);
+		return -ENOMEM;
+	}
+
+	urb = &rt->receiver;
+	rt->serial = 1;
+	rt->chip = chip;
+	usb_init_urb(urb);
+	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) {
+		kfree(rt->receiver_buffer);
+		kfree(rt);
+		dev_err(&chip->dev->dev, "cannot create comm data receiver.");
+		return ret;
+	}
+	chip->comm = rt;
+	return 0;
+}
+
+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)
+{
+	struct comm_runtime *rt = chip->comm;
+
+	kfree(rt->receiver_buffer);
+	kfree(rt);
+	chip->comm = NULL;
+}
diff --git a/sound/usb/6fire/comm.h b/sound/usb/6fire/comm.h
new file mode 100644
index 000000000..2447d7ecf
--- /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..6b0bb096f
--- /dev/null
+++ b/sound/usb/6fire/midi.c
@@ -0,0 +1,202 @@
+// 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
+};
+
+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) {
+		kfree(rt);
+		return -ENOMEM;
+	}
+
+	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) {
+		kfree(rt->out_buffer);
+		kfree(rt);
+		dev_err(&chip->dev->dev, "unable to create midi.\n");
+		return ret;
+	}
+	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;
+}
+
+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)
+{
+	struct midi_runtime *rt = chip->midi;
+
+	kfree(rt->out_buffer);
+	kfree(rt);
+	chip->midi = NULL;
+}
diff --git a/sound/usb/6fire/midi.h b/sound/usb/6fire/midi.h
new file mode 100644
index 000000000..47640c845
--- /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..d2e274b73
--- /dev/null
+++ b/sound/usb/6fire/pcm.c
@@ -0,0 +1,670 @@
+// 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].packets[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;
+	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 */
+		if (urb->packets[i].actual_length > 4)
+			frame_count = (urb->packets[i].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 += urb->packets[i].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;
+	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 */
+		if (urb->packets[i].length > 4)
+			frame_count = (urb->packets[i].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;
+	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++)
+		if (in_urb->packets[i].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++) {
+		out_urb->packets[i].offset = total_length;
+		out_urb->packets[i].length = (in_urb->packets[i].actual_length
+				- 4) / (rt->in_n_analog << 2)
+				* (rt->out_n_analog << 2) + 4;
+		out_urb->packets[i].status = 0;
+		total_length += out_urb->packets[i].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++)
+		if (out_urb->packets[i].length >= 4) {
+			frame_count = (out_urb->packets[i].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 void usb6fire_pcm_init_urb(struct pcm_urb *urb,
+				  struct sfire_chip *chip, bool in, int ep,
+				  void (*handler)(struct urb *))
+{
+	urb->chip = chip;
+	usb_init_urb(&urb->instance);
+	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;
+}
+
+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_buffers_destroy(struct pcm_runtime *rt)
+{
+	int i;
+
+	for (i = 0; i < PCM_N_URBS; i++) {
+		kfree(rt->out_urbs[i].buffer);
+		kfree(rt->in_urbs[i].buffer);
+	}
+}
+
+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) {
+		usb6fire_pcm_buffers_destroy(rt);
+		kfree(rt);
+		return ret;
+	}
+
+	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++) {
+		usb6fire_pcm_init_urb(&rt->in_urbs[i], chip, true, IN_EP,
+				usb6fire_pcm_in_urb_handler);
+		usb6fire_pcm_init_urb(&rt->out_urbs[i], chip, false, OUT_EP,
+				usb6fire_pcm_out_urb_handler);
+
+		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) {
+		usb6fire_pcm_buffers_destroy(rt);
+		kfree(rt);
+		dev_err(&chip->dev->dev, "cannot create pcm instance.\n");
+		return ret;
+	}
+
+	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;
+}
+
+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)
+{
+	struct pcm_runtime *rt = chip->pcm;
+
+	usb6fire_pcm_buffers_destroy(rt);
+	kfree(rt);
+	chip->pcm = NULL;
+}
diff --git a/sound/usb/6fire/pcm.h b/sound/usb/6fire/pcm.h
new file mode 100644
index 000000000..5a092dfd6
--- /dev/null
+++ b/sound/usb/6fire/pcm.h
@@ -0,0 +1,71 @@
+/* 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;
+
+	/* BEGIN DO NOT SEPARATE */
+	struct urb instance;
+	struct usb_iso_packet_descriptor packets[PCM_N_PACKETS_PER_URB];
+	/* END DO NOT SEPARATE */
+	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..c5c542d17
--- /dev/null
+++ b/sound/usb/bcd2000/bcd2000.c
@@ -0,0 +1,457 @@
+// 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;
+
+	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;
+	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;
+
+	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 */
+	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;
+
+	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_free_usb_related_resources(struct bcd2000 *bcd2k,
+						struct usb_interface *interface)
+{
+	usb_poison_urb(bcd2k->midi_out_urb);
+	usb_poison_urb(bcd2k->midi_in_urb);
+
+	usb_free_urb(bcd2k->midi_out_urb);
+	usb_free_urb(bcd2k->midi_in_urb);
+	bcd2k->midi_out_urb = NULL;
+	bcd2k->midi_in_urb = NULL;
+
+	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;
+
+	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..ba3f73455
--- /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) {
+		kfree(cdev->data_cb_info);
+		free_urbs(cdev->data_urbs_in);
+		return ret;
+	}
+
+	cdev->data_urbs_out = alloc_urbs(cdev, SNDRV_PCM_STREAM_PLAYBACK, &ret);
+	if (ret < 0) {
+		kfree(cdev->data_cb_info);
+		free_urbs(cdev->data_urbs_in);
+		free_urbs(cdev->data_urbs_out);
+		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);
+	free_urbs(cdev->data_urbs_out);
+	kfree(cdev->data_cb_info);
+}
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..a16e59248
--- /dev/null
+++ b/sound/usb/caiaq/device.c
@@ -0,0 +1,594 @@
+// 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);
+}
+
+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;
+	}
+
+	usb_init_urb(&cdev->ep1_in_urb);
+	usb_init_urb(&cdev->midi_out_urb);
+
+	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);
+		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..743eb0387
--- /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..c656d0162
--- /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..e34d92d57
--- /dev/null
+++ b/sound/usb/card.h
@@ -0,0 +1,227 @@
+/* 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_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..0835943d7
--- /dev/null
+++ b/sound/usb/endpoint.c
@@ -0,0 +1,1919 @@
+// 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);
+	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 = packet->packets;
+			memcpy(ctx->packet_size, packet->packet_size,
+			       packet->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)
+{
+	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) {
+		INIT_LIST_HEAD(&ep->ready_playback_urbs);
+		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);
+	}
+
+	/* 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;
+
+		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
+			u->packets++; /* for transfer delimiter */
+		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..5fc2131b4
--- /dev/null
+++ b/sound/usb/fcp.c
@@ -0,0 +1,1143 @@
+// 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;
+
+	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;
+
+	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..cd1a4c871
--- /dev/null
+++ b/sound/usb/hiface/pcm.c
@@ -0,0 +1,594 @@
+// 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;
+	usb_init_urb(&urb->instance);
+
+	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 hiface_chip *chip)
+{
+	struct pcm_runtime *rt = chip->pcm;
+	int i;
+
+	for (i = 0; i < PCM_N_URBS; i++)
+		kfree(rt->out_urbs[i].buffer);
+
+	kfree(chip->pcm);
+	chip->pcm = NULL;
+}
+
+static void hiface_pcm_free(struct snd_pcm *pcm)
+{
+	struct pcm_runtime *rt = pcm->private_data;
+
+	if (rt)
+		hiface_pcm_destroy(rt->chip);
+}
+
+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:
+	for (i = 0; i < PCM_N_URBS; i++)
+		kfree(rt->out_urbs[i].buffer);
+	kfree(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..77f06da93
--- /dev/null
+++ b/sound/usb/implicit.c
@@ -0,0 +1,494 @@
+// 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[] = {
+	{} /* 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..7ebaf125f
--- /dev/null
+++ b/sound/usb/line6/playback.c
@@ -0,0 +1,438 @@
+// 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;
+
+		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..8a9bc37f0
--- /dev/null
+++ b/sound/usb/midi.c
@@ -0,0 +1,2657 @@
+/*
+ * 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;
+	}
+	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..b9a62e94e
--- /dev/null
+++ b/sound/usb/misc/ua101.c
@@ -0,0 +1,1337 @@
+// 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 usb_iso_packet_descriptor iso_frame_desc[1];
+			struct list_head ready_list;
+		} *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 *usb_urb)
+{
+	struct ua101_urb *urb = (struct ua101_urb *)usb_urb;
+	struct ua101 *ua = urb->urb.context;
+
+	if (unlikely(urb->urb.status == -ENOENT ||	/* unlinked */
+		     urb->urb.status == -ENODEV ||	/* device removed */
+		     urb->urb.status == -ECONNRESET ||	/* unlinked */
+		     urb->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(&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->urb.iso_frame_desc[0].length /
+						ua->playback.frame_bytes;
+	}
+}
+
+static void first_playback_urb_complete(struct urb *urb)
+{
+	struct ua101 *ua = urb->context;
+
+	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 *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 */
+			urb = list_first_entry(&ua->ready_playback_urbs,
+					       struct ua101_urb, ready_list);
+			list_del(&urb->ready_list);
+
+			/* fill packet with data or silence */
+			urb->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->urb,
+									frames);
+			else
+				memset(urb->urb.transfer_buffer, 0,
+				       urb->urb.iso_frame_desc[0].length);
+
+			/* and off you go ... */
+			err = usb_submit_urb(&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 *ua = urb->context;
+	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 *ua = urb->context;
+
+	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])
+			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);
+	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 ua101_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 = kmalloc_obj(*urb);
+			if (!urb)
+				return -ENOMEM;
+			usb_init_urb(&urb->urb);
+			urb->urb.dev = ua->dev;
+			urb->urb.pipe = stream->usb_pipe;
+			urb->urb.transfer_flags = URB_NO_TRANSFER_DMA_MAP;
+			urb->urb.transfer_buffer = addr;
+			urb->urb.transfer_dma = dma;
+			urb->urb.transfer_buffer_length = max_packet_size;
+			urb->urb.number_of_packets = 1;
+			urb->urb.interval = 1;
+			urb->urb.context = ua;
+			urb->urb.complete = urb_complete;
+			urb->urb.iso_frame_desc[0].offset = 0;
+			urb->urb.iso_frame_desc[0].length = max_packet_size;
+			stream->urbs[u++] = urb;
+			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) {
+		kfree(stream->urbs[i]);
+		stream->urbs[i] = 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..ace4ccad8
--- /dev/null
+++ b/sound/usb/mixer_maps.c
@@ -0,0 +1,822 @@
+// 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 */
+	{}
+};
+
+/*
+ * 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(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,
+	},
+	{
+		/* 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 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..a1f5592cc
--- /dev/null
+++ b/sound/usb/mixer_quirks.c
@@ -0,0 +1,4808 @@
+// 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;
+
+	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;
+
+	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..2e5a8d37e
--- /dev/null
+++ b/sound/usb/mixer_s1810c.c
@@ -0,0 +1,699 @@
+// 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;
+
+	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;
+
+	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..673eb8d87
--- /dev/null
+++ b/sound/usb/mixer_scarlett.c
@@ -0,0 +1,1456 @@
+// 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;
+
+	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..502854cc9
--- /dev/null
+++ b/sound/usb/mixer_scarlett2.c
@@ -0,0 +1,9911 @@
+// 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(
+	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;
+}
+
+/* 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)
+{
+	int err;
+
+	err = scarlett2_usb_activate_config(mixer, SCARLETT2_USB_CONFIG_SAVE);
+	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(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..ebff185cb
--- /dev/null
+++ b/sound/usb/mixer_us16x08.c
@@ -0,0 +1,1446 @@
+// 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)
+{
+
+	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)
+{
+	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..919381729
--- /dev/null
+++ b/sound/usb/quirks.c
@@ -0,0 +1,2804 @@
+// 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;
+}
+
+/*
+ * 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);
+	}
+
+	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, 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(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(0x2708, 0x0002, /* Audient iD14 */
+		   QUIRK_FLAG_IGNORE_CTL_ERROR),
+	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(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(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..f00b53346
--- /dev/null
+++ b/sound/usb/usx2y/us122l.c
@@ -0,0 +1,682 @@
+// 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 && area->vm_flags & VM_WRITE)
+		return -EPERM;
+	/* 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..4190227c5
--- /dev/null
+++ b/sound/usb/usx2y/usbusx2y.c
@@ -0,0 +1,483 @@
+// 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 (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 < 21; 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);
+
+	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 = kmalloc(21, 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, 21,
+			 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..6a76d04bf
--- /dev/null
+++ b/sound/usb/usx2y/usbusx2y.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef USBUSX2Y_H
+#define USBUSX2Y_H
+#include "../usbaudio.h"
+#include "../midi.h"
+#include "usbus428ctldefs.h"
+
+#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[24];
+	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;
+}