ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

11 files changed, 2843 insertions, 0 deletions

diff --git a/drivers/hid/i2c-hid/Kconfig b/drivers/hid/i2c-hid/Kconfig
new file mode 100644
index 000000000..e8d51f410
--- /dev/null
+++ b/drivers/hid/i2c-hid/Kconfig
@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menuconfig I2C_HID
+	tristate "I2C HID support"
+	default y
+	depends on I2C
+
+if I2C_HID
+
+config I2C_HID_ACPI
+	tristate "HID over I2C transport layer ACPI driver"
+	depends on ACPI
+	depends on DRM || !DRM
+	select I2C_HID_CORE
+	help
+	  Say Y here if you use a keyboard, a touchpad, a touchscreen, or any
+	  other HID based devices which is connected to your computer via I2C.
+	  This driver supports ACPI-based systems.
+
+	  If unsure, say N.
+
+	  This support is also available as a module.  If so, the module
+	  will be called i2c-hid-acpi.  It will also build/depend on the
+	  module i2c-hid.
+
+config I2C_HID_OF
+	tristate "HID over I2C transport layer Open Firmware driver"
+	# No "depends on OF" because this can also be used for manually
+	# (board-file) instantiated "hid-over-i2c" type i2c-clients.
+	depends on DRM || !DRM
+	select I2C_HID_CORE
+	help
+	  Say Y here if you use a keyboard, a touchpad, a touchscreen, or any
+	  other HID based devices which is connected to your computer via I2C.
+	  This driver supports Open Firmware (Device Tree)-based systems as
+	  well as binding to manually (board-file) instantiated i2c-hid-clients.
+
+	  If unsure, say N.
+
+	  This support is also available as a module.  If so, the module
+	  will be called i2c-hid-of.  It will also build/depend on the
+	  module i2c-hid.
+
+config I2C_HID_OF_ELAN
+	tristate "Driver for Elan hid-i2c based devices on OF systems"
+	depends on OF
+	depends on DRM || !DRM
+	select I2C_HID_CORE
+	help
+	  Say Y here if you want support for Elan i2c devices that use
+	  the i2c-hid protocol on Open Firmware (Device Tree)-based
+	  systems.
+
+	  If unsure, say N.
+
+	  This support is also available as a module.  If so, the module
+	  will be called i2c-hid-of-elan.  It will also build/depend on
+	  the module i2c-hid.
+
+config I2C_HID_OF_GOODIX
+	tristate "Driver for Goodix hid-i2c based devices on OF systems"
+	depends on OF
+	depends on DRM || !DRM
+	select I2C_HID_CORE
+	help
+	  Say Y here if you want support for Goodix i2c devices that use
+	  the i2c-hid protocol on Open Firmware (Device Tree)-based
+	  systems.
+
+	  If unsure, say N.
+
+	  This support is also available as a module.  If so, the module
+	  will be called i2c-hid-of-goodix.  It will also build/depend on
+	  the module i2c-hid.
+
+config I2C_HID_CORE
+	tristate
+	# We need to call into panel code so if DRM=m, this can't be 'y'
+	depends on DRM || !DRM
+endif
+
diff --git a/drivers/hid/i2c-hid/Makefile b/drivers/hid/i2c-hid/Makefile
new file mode 100644
index 000000000..38d5d827f
--- /dev/null
+++ b/drivers/hid/i2c-hid/Makefile
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the I2C input drivers
+#
+
+obj-$(CONFIG_I2C_HID_CORE)			+= i2c-hid.o
+
+i2c-hid-objs					=  i2c-hid-core.o
+i2c-hid-$(CONFIG_DMI)				+= i2c-hid-dmi-quirks.o
+
+obj-$(CONFIG_I2C_HID_ACPI)			+= i2c-hid-acpi.o i2c-hid-acpi-prp0001.o
+obj-$(CONFIG_I2C_HID_OF)			+= i2c-hid-of.o
+obj-$(CONFIG_I2C_HID_OF_ELAN)			+= i2c-hid-of-elan.o
+obj-$(CONFIG_I2C_HID_OF_GOODIX)			+= i2c-hid-of-goodix.o
diff --git a/drivers/hid/i2c-hid/i2c-hid-acpi-prp0001.c b/drivers/hid/i2c-hid/i2c-hid-acpi-prp0001.c
new file mode 100644
index 000000000..d2cf4714a
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-acpi-prp0001.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HID over I2C driver for PRP0001 devices missing hid-descr-addr
+ *
+ * Some devices, for example the Lenovo KaiTian N60d and Inspur CP300L3, use
+ * _HID "PRP0001" with _DSD compatible "hid-over-i2c" but lack "hid-descr-addr"
+ * from the _DSD. The HID descriptor address is provided only through an ACPI
+ * _DSM. The TPD0 node in the DSDT shows _DSM Function 1 returning 0x20.
+ *
+ * Copyright (C) 2026 谢致邦 (XIE Zhibang) <Yeking@Red54.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include "i2c-hid.h"
+#include "i2c-hid-acpi.h"
+
+static int i2c_hid_acpi_prp0001_power_up(struct i2chid_ops *ops)
+{
+	/* give the device time to power up */
+	msleep(750);
+	return 0;
+}
+
+static struct i2chid_ops i2c_hid_acpi_prp0001_ops = {
+	.power_up = i2c_hid_acpi_prp0001_power_up,
+	/*
+	 * No .restore_sequence needed: the _DSM on these devices returns a
+	 * constant (0x20) with no side effects, unlike some PNP0C50 _DSM
+	 * implementations that switch the hardware between PS/2 and I2C modes.
+	 */
+};
+
+static int i2c_hid_acpi_prp0001_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct acpi_device *adev;
+	u16 hid_descriptor_address;
+	int ret;
+
+	/* If hid-descr-addr is present, let i2c-hid-of handle it */
+	if (device_property_present(dev, "hid-descr-addr"))
+		return -ENODEV;
+
+	adev = ACPI_COMPANION(dev);
+	if (!adev)
+		return -ENODEV;
+
+	ret = i2c_hid_acpi_get_descriptor(adev);
+	if (ret < 0)
+		return ret;
+	dev_warn(dev,
+		 "hid-descr-addr device property NOT found, using ACPI _DSM fallback. Contact vendor for firmware update!\n");
+	hid_descriptor_address = ret;
+
+	/*
+	 * No acpi_device_fix_up_power() needed: TPD0 has no _PS0, _PS3, _PSC
+	 * or _PRx methods and follows I2C bus power.
+	 */
+	return i2c_hid_core_probe(client, &i2c_hid_acpi_prp0001_ops,
+				  hid_descriptor_address, 0);
+}
+
+static const struct of_device_id i2c_hid_acpi_prp0001_of_match[] = {
+	{ .compatible = "hid-over-i2c" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, i2c_hid_acpi_prp0001_of_match);
+
+static const struct i2c_device_id i2c_hid_acpi_prp0001_id[] = {
+	{ .name = "hid-over-i2c" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, i2c_hid_acpi_prp0001_id);
+
+static struct i2c_driver i2c_hid_acpi_prp0001_driver = {
+	.driver = {
+		.name	= "i2c_hid_acpi_prp0001",
+		.pm	= &i2c_hid_core_pm,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		/*
+		 * of_match_ptr() makes this NULL when CONFIG_OF=n, but that's
+		 * fine: the I2C id_table with "hid-over-i2c" handles matching
+		 * via client->name (set by acpi_set_modalias() from the _DSD
+		 * compatible property).
+		 */
+		.of_match_table = of_match_ptr(i2c_hid_acpi_prp0001_of_match),
+	},
+
+	.probe		= i2c_hid_acpi_prp0001_probe,
+	.remove		= i2c_hid_core_remove,
+	.shutdown	= i2c_hid_core_shutdown,
+	.id_table	= i2c_hid_acpi_prp0001_id,
+};
+
+module_i2c_driver(i2c_hid_acpi_prp0001_driver);
+
+MODULE_DESCRIPTION("HID over I2C driver for PRP0001 devices missing hid-descr-addr");
+MODULE_AUTHOR("谢致邦 (XIE Zhibang) <Yeking@Red54.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/i2c-hid/i2c-hid-acpi.c b/drivers/hid/i2c-hid/i2c-hid-acpi.c
new file mode 100644
index 000000000..13f977d6a
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-acpi.c
@@ -0,0 +1,119 @@
+/*
+ * HID over I2C ACPI Subclass
+ *
+ * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
+ * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
+ * Copyright (c) 2012 Red Hat, Inc
+ *
+ * This code was forked out of the core code, which was partly based on
+ * "USB HID support for Linux":
+ *
+ *  Copyright (c) 1999 Andreas Gal
+ *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
+ *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
+ *  Copyright (c) 2007-2008 Oliver Neukum
+ *  Copyright (c) 2006-2010 Jiri Kosina
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive for
+ * more details.
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+
+#include "i2c-hid.h"
+#include "i2c-hid-acpi.h"
+
+struct i2c_hid_acpi {
+	struct i2chid_ops ops;
+	struct acpi_device *adev;
+};
+
+static const struct acpi_device_id i2c_hid_acpi_blacklist[] = {
+	/*
+	 * The CHPN0001 ACPI device, which is used to describe the Chipone
+	 * ICN8505 controller, has a _CID of PNP0C50 but is not HID compatible.
+	 */
+	{ "CHPN0001" },
+	/*
+	 * The IDEA5002 ACPI device causes high interrupt usage and spurious
+	 * wakeups from suspend.
+	 */
+	{ "IDEA5002" },
+	{ }
+};
+
+static void i2c_hid_acpi_restore_sequence(struct i2chid_ops *ops)
+{
+	struct i2c_hid_acpi *ihid_acpi = container_of(ops, struct i2c_hid_acpi, ops);
+
+	i2c_hid_acpi_get_descriptor(ihid_acpi->adev);
+}
+
+static void i2c_hid_acpi_shutdown_tail(struct i2chid_ops *ops)
+{
+	struct i2c_hid_acpi *ihid_acpi = container_of(ops, struct i2c_hid_acpi, ops);
+
+	acpi_device_set_power(ihid_acpi->adev, ACPI_STATE_D3_COLD);
+}
+
+static int i2c_hid_acpi_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+	struct i2c_hid_acpi *ihid_acpi;
+	u16 hid_descriptor_address;
+	int ret;
+
+	if (acpi_match_device_ids(adev, i2c_hid_acpi_blacklist) == 0)
+		return -ENODEV;
+
+	ret = i2c_hid_acpi_get_descriptor(adev);
+	if (ret < 0)
+		return ret;
+	hid_descriptor_address = ret;
+
+	ihid_acpi = devm_kzalloc(dev, sizeof(*ihid_acpi), GFP_KERNEL);
+	if (!ihid_acpi)
+		return -ENOMEM;
+
+	ihid_acpi->adev = adev;
+	ihid_acpi->ops.shutdown_tail = i2c_hid_acpi_shutdown_tail;
+	ihid_acpi->ops.restore_sequence = i2c_hid_acpi_restore_sequence;
+
+	acpi_device_fix_up_power(adev);
+
+	return i2c_hid_core_probe(client, &ihid_acpi->ops,
+				  hid_descriptor_address, 0);
+}
+
+static const struct acpi_device_id i2c_hid_acpi_match[] = {
+	{ "ACPI0C50" },
+	{ "PNP0C50" },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
+
+static struct i2c_driver i2c_hid_acpi_driver = {
+	.driver = {
+		.name	= "i2c_hid_acpi",
+		.pm	= &i2c_hid_core_pm,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.acpi_match_table = i2c_hid_acpi_match,
+	},
+
+	.probe		= i2c_hid_acpi_probe,
+	.remove		= i2c_hid_core_remove,
+	.shutdown	= i2c_hid_core_shutdown,
+};
+
+module_i2c_driver(i2c_hid_acpi_driver);
+
+MODULE_DESCRIPTION("HID over I2C ACPI driver");
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/i2c-hid/i2c-hid-acpi.h b/drivers/hid/i2c-hid/i2c-hid-acpi.h
new file mode 100644
index 000000000..0bbed1853
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-acpi.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _I2C_HID_ACPI_H
+#define _I2C_HID_ACPI_H
+
+#include <linux/acpi.h>
+#include <linux/uuid.h>
+
+static inline int i2c_hid_acpi_get_descriptor(struct acpi_device *adev)
+{
+	/* HID I²C Device: 3cdff6f7-4267-4555-ad05-b30a3d8938de */
+	static const guid_t i2c_hid_guid =
+		GUID_INIT(0x3CDFF6F7, 0x4267, 0x4555,
+			  0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE);
+
+	acpi_handle handle = acpi_device_handle(adev);
+	union acpi_object *obj;
+	u16 addr;
+
+	obj = acpi_evaluate_dsm_typed(handle, &i2c_hid_guid,
+				      1, 1, NULL, ACPI_TYPE_INTEGER);
+	if (!obj) {
+		acpi_handle_err(handle,
+				"Error _DSM call to get HID descriptor address failed\n");
+		return -ENODEV;
+	}
+
+	addr = obj->integer.value;
+	ACPI_FREE(obj);
+	return addr;
+}
+
+#endif
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
new file mode 100644
index 000000000..0e725a0f0
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -0,0 +1,1410 @@
+/*
+ * HID over I2C protocol implementation
+ *
+ * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
+ * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
+ * Copyright (c) 2012 Red Hat, Inc
+ *
+ * This code is partly based on "USB HID support for Linux":
+ *
+ *  Copyright (c) 1999 Andreas Gal
+ *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
+ *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
+ *  Copyright (c) 2007-2008 Oliver Neukum
+ *  Copyright (c) 2006-2010 Jiri Kosina
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/irq.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/pm.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/device.h>
+#include <linux/wait.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/hid.h>
+#include <linux/mutex.h>
+#include <linux/unaligned.h>
+
+#include <drm/drm_panel.h>
+
+#include "../hid-ids.h"
+#include "i2c-hid.h"
+
+/* quirks to control the device */
+#define I2C_HID_QUIRK_NO_IRQ_AFTER_RESET	BIT(0)
+#define I2C_HID_QUIRK_BOGUS_IRQ			BIT(1)
+#define I2C_HID_QUIRK_RESET_ON_RESUME		BIT(2)
+#define I2C_HID_QUIRK_BAD_INPUT_SIZE		BIT(3)
+#define I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET	BIT(4)
+#define I2C_HID_QUIRK_NO_SLEEP_ON_SUSPEND	BIT(5)
+#define I2C_HID_QUIRK_DELAY_WAKEUP_AFTER_RESUME BIT(6)
+#define I2C_HID_QUIRK_RE_POWER_ON		BIT(7)
+
+/* Command opcodes */
+#define I2C_HID_OPCODE_RESET			0x01
+#define I2C_HID_OPCODE_GET_REPORT		0x02
+#define I2C_HID_OPCODE_SET_REPORT		0x03
+#define I2C_HID_OPCODE_GET_IDLE			0x04
+#define I2C_HID_OPCODE_SET_IDLE			0x05
+#define I2C_HID_OPCODE_GET_PROTOCOL		0x06
+#define I2C_HID_OPCODE_SET_PROTOCOL		0x07
+#define I2C_HID_OPCODE_SET_POWER		0x08
+
+/* flags */
+#define I2C_HID_STARTED		0
+#define I2C_HID_RESET_PENDING	1
+
+#define I2C_HID_PWR_ON		0x00
+#define I2C_HID_PWR_SLEEP	0x01
+
+#define i2c_hid_dbg(ihid, ...) dev_dbg(&(ihid)->client->dev, __VA_ARGS__)
+
+struct i2c_hid_desc {
+	__le16 wHIDDescLength;
+	__le16 bcdVersion;
+	__le16 wReportDescLength;
+	__le16 wReportDescRegister;
+	__le16 wInputRegister;
+	__le16 wMaxInputLength;
+	__le16 wOutputRegister;
+	__le16 wMaxOutputLength;
+	__le16 wCommandRegister;
+	__le16 wDataRegister;
+	__le16 wVendorID;
+	__le16 wProductID;
+	__le16 wVersionID;
+	__le32 reserved;
+} __packed;
+
+/* The main device structure */
+struct i2c_hid {
+	struct i2c_client	*client;	/* i2c client */
+	struct hid_device	*hid;	/* pointer to corresponding HID dev */
+	struct i2c_hid_desc hdesc;		/* the HID Descriptor */
+	__le16			wHIDDescRegister; /* location of the i2c
+						   * register of the HID
+						   * descriptor. */
+	unsigned int		bufsize;	/* i2c buffer size */
+	u8			*inbuf;		/* Input buffer */
+	u8			*rawbuf;	/* Raw Input buffer */
+	u8			*cmdbuf;	/* Command buffer */
+
+	unsigned long		flags;		/* device flags */
+	unsigned long		quirks;		/* Various quirks */
+
+	wait_queue_head_t	wait;		/* For waiting the interrupt */
+
+	struct mutex		cmd_lock;	/* protects cmdbuf and rawbuf */
+	struct mutex		reset_lock;
+
+	struct i2chid_ops	*ops;
+	struct drm_panel_follower panel_follower;
+	struct work_struct	panel_follower_work;
+	bool			is_panel_follower;
+	bool			panel_follower_work_finished;
+};
+
+static const struct i2c_hid_quirks {
+	__u16 idVendor;
+	__u16 idProduct;
+	__u32 quirks;
+} i2c_hid_quirks[] = {
+	{ I2C_VENDOR_ID_HANTICK, I2C_PRODUCT_ID_HANTICK_5288,
+		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
+	{ I2C_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_VOYO_WINPAD_A15,
+		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
+	{ I2C_VENDOR_ID_RAYDIUM, I2C_PRODUCT_ID_RAYDIUM_3118,
+		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
+	{ USB_VENDOR_ID_ALPS_JP, HID_ANY_ID,
+		 I2C_HID_QUIRK_RESET_ON_RESUME },
+	{ I2C_VENDOR_ID_SYNAPTICS, I2C_PRODUCT_ID_SYNAPTICS_SYNA2393,
+		 I2C_HID_QUIRK_RESET_ON_RESUME },
+	{ USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720,
+		I2C_HID_QUIRK_BAD_INPUT_SIZE },
+	{ I2C_VENDOR_ID_CIRQUE, I2C_PRODUCT_ID_CIRQUE_1063,
+		I2C_HID_QUIRK_NO_SLEEP_ON_SUSPEND },
+	/*
+	 * Without additional power on command, at least some QTEC devices send garbage
+	 */
+	{ I2C_VENDOR_ID_QTEC, HID_ANY_ID,
+		I2C_HID_QUIRK_RE_POWER_ON },
+	/*
+	 * Sending the wakeup after reset actually break ELAN touchscreen controller
+	 */
+	{ USB_VENDOR_ID_ELAN, HID_ANY_ID,
+		 I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET |
+		 I2C_HID_QUIRK_BOGUS_IRQ },
+	{ I2C_VENDOR_ID_GOODIX, I2C_DEVICE_ID_GOODIX_0D42,
+		 I2C_HID_QUIRK_DELAY_WAKEUP_AFTER_RESUME },
+	{ I2C_VENDOR_ID_BLTP, I2C_PRODUCT_ID_BLTP7853,
+		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
+	{ 0, 0 }
+};
+
+/*
+ * i2c_hid_lookup_quirk: return any quirks associated with a I2C HID device
+ * @idVendor: the 16-bit vendor ID
+ * @idProduct: the 16-bit product ID
+ *
+ * Returns: a u32 quirks value.
+ */
+static u32 i2c_hid_lookup_quirk(const u16 idVendor, const u16 idProduct)
+{
+	u32 quirks = 0;
+	int n;
+
+	for (n = 0; i2c_hid_quirks[n].idVendor; n++)
+		if (i2c_hid_quirks[n].idVendor == idVendor &&
+		    (i2c_hid_quirks[n].idProduct == (__u16)HID_ANY_ID ||
+		     i2c_hid_quirks[n].idProduct == idProduct))
+			quirks = i2c_hid_quirks[n].quirks;
+
+	return quirks;
+}
+
+static int i2c_hid_probe_address(struct i2c_hid *ihid)
+{
+	int ret;
+
+	/*
+	 * Some STM-based devices need 400µs after a rising clock edge to wake
+	 * from deep sleep, in which case the first read will fail. Try after a
+	 * short sleep to see if the device came alive on the bus. Certain
+	 * Weida Tech devices also need this.
+	 */
+	ret = i2c_smbus_read_byte(ihid->client);
+	if (ret < 0) {
+		usleep_range(400, 500);
+		ret = i2c_smbus_read_byte(ihid->client);
+	}
+	return ret < 0 ? ret : 0;
+}
+
+static int i2c_hid_xfer(struct i2c_hid *ihid,
+			u8 *send_buf, int send_len, u8 *recv_buf, int recv_len)
+{
+	struct i2c_client *client = ihid->client;
+	struct i2c_msg msgs[2] = { 0 };
+	int n = 0;
+	int ret;
+
+	if (send_len) {
+		i2c_hid_dbg(ihid, "%s: cmd=%*ph\n",
+			    __func__, send_len, send_buf);
+
+		msgs[n].addr = client->addr;
+		msgs[n].flags = (client->flags & I2C_M_TEN) | I2C_M_DMA_SAFE;
+		msgs[n].len = send_len;
+		msgs[n].buf = send_buf;
+		n++;
+	}
+
+	if (recv_len) {
+		msgs[n].addr = client->addr;
+		msgs[n].flags = (client->flags & I2C_M_TEN) |
+				I2C_M_RD | I2C_M_DMA_SAFE;
+		msgs[n].len = recv_len;
+		msgs[n].buf = recv_buf;
+		n++;
+	}
+
+	ret = i2c_transfer(client->adapter, msgs, n);
+
+	if (ret != n)
+		return ret < 0 ? ret : -EIO;
+
+	return 0;
+}
+
+static int i2c_hid_read_register(struct i2c_hid *ihid, __le16 reg,
+				 void *buf, size_t len)
+{
+	guard(mutex)(&ihid->cmd_lock);
+
+	*(__le16 *)ihid->cmdbuf = reg;
+
+	return i2c_hid_xfer(ihid, ihid->cmdbuf, sizeof(__le16), buf, len);
+}
+
+static size_t i2c_hid_encode_command(u8 *buf, u8 opcode,
+				     int report_type, int report_id)
+{
+	size_t length = 0;
+
+	if (report_id < 0x0F) {
+		buf[length++] = report_type << 4 | report_id;
+		buf[length++] = opcode;
+	} else {
+		buf[length++] = report_type << 4 | 0x0F;
+		buf[length++] = opcode;
+		buf[length++] = report_id;
+	}
+
+	return length;
+}
+
+static int i2c_hid_get_report(struct i2c_hid *ihid,
+			      u8 report_type, u8 report_id,
+			      u8 *recv_buf, size_t recv_len)
+{
+	size_t length = 0;
+	size_t ret_count;
+	int error;
+
+	i2c_hid_dbg(ihid, "%s\n", __func__);
+
+	guard(mutex)(&ihid->cmd_lock);
+
+	/* Command register goes first */
+	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
+	length += sizeof(__le16);
+	/* Next is GET_REPORT command */
+	length += i2c_hid_encode_command(ihid->cmdbuf + length,
+					 I2C_HID_OPCODE_GET_REPORT,
+					 report_type, report_id);
+	/*
+	 * Device will send report data through data register. Because
+	 * command can be either 2 or 3 bytes destination for the data
+	 * register may be not aligned.
+	 */
+	put_unaligned_le16(le16_to_cpu(ihid->hdesc.wDataRegister),
+			   ihid->cmdbuf + length);
+	length += sizeof(__le16);
+
+	/*
+	 * In addition to report data device will supply data length
+	 * in the first 2 bytes of the response, so adjust .
+	 */
+	recv_len = min(recv_len, ihid->bufsize - sizeof(__le16));
+	error = i2c_hid_xfer(ihid, ihid->cmdbuf, length,
+			     ihid->rawbuf, recv_len + sizeof(__le16));
+	if (error) {
+		dev_err(&ihid->client->dev,
+			"failed to get a report from device: %d\n", error);
+		return error;
+	}
+
+	/* The buffer is sufficiently aligned */
+	ret_count = le16_to_cpup((__le16 *)ihid->rawbuf);
+
+	/* Check for empty report response */
+	if (ret_count <= sizeof(__le16))
+		return 0;
+
+	recv_len = min(recv_len, ret_count - sizeof(__le16));
+	memcpy(recv_buf, ihid->rawbuf + sizeof(__le16), recv_len);
+
+	if (report_id && recv_len != 0 && recv_buf[0] != report_id) {
+		dev_err(&ihid->client->dev,
+			"device returned incorrect report (%d vs %d expected)\n",
+			recv_buf[0], report_id);
+		return -EINVAL;
+	}
+
+	return recv_len;
+}
+
+static size_t i2c_hid_format_report(u8 *buf, int report_id,
+				    const u8 *data, size_t size)
+{
+	size_t length = sizeof(__le16); /* reserve space to store size */
+
+	if (report_id)
+		buf[length++] = report_id;
+
+	memcpy(buf + length, data, size);
+	length += size;
+
+	/* Store overall size in the beginning of the buffer */
+	put_unaligned_le16(length, buf);
+
+	return length;
+}
+
+/**
+ * i2c_hid_set_or_send_report: forward an incoming report to the device
+ * @ihid: the i2c hid device
+ * @report_type: 0x03 for HID_FEATURE_REPORT ; 0x02 for HID_OUTPUT_REPORT
+ * @report_id: the report ID
+ * @buf: the actual data to transfer, without the report ID
+ * @data_len: size of buf
+ * @do_set: true: use SET_REPORT HID command, false: send plain OUTPUT report
+ */
+static int i2c_hid_set_or_send_report(struct i2c_hid *ihid,
+				      u8 report_type, u8 report_id,
+				      const u8 *buf, size_t data_len,
+				      bool do_set)
+{
+	size_t length = 0;
+	int error;
+
+	i2c_hid_dbg(ihid, "%s\n", __func__);
+
+	if (data_len > ihid->bufsize)
+		return -EINVAL;
+
+	if (!do_set && le16_to_cpu(ihid->hdesc.wMaxOutputLength) == 0)
+		return -ENOSYS;
+
+	guard(mutex)(&ihid->cmd_lock);
+
+	if (do_set) {
+		/* Command register goes first */
+		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
+		length += sizeof(__le16);
+		/* Next is SET_REPORT command */
+		length += i2c_hid_encode_command(ihid->cmdbuf + length,
+						 I2C_HID_OPCODE_SET_REPORT,
+						 report_type, report_id);
+		/*
+		 * Report data will go into the data register. Because
+		 * command can be either 2 or 3 bytes destination for
+		 * the data register may be not aligned.
+		*/
+		put_unaligned_le16(le16_to_cpu(ihid->hdesc.wDataRegister),
+				   ihid->cmdbuf + length);
+		length += sizeof(__le16);
+	} else {
+		/*
+		 * With simple "send report" all data goes into the output
+		 * register.
+		 */
+		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wOutputRegister;
+		length += sizeof(__le16);
+	}
+
+	length += i2c_hid_format_report(ihid->cmdbuf + length,
+					report_id, buf, data_len);
+
+	error = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
+	if (error) {
+		dev_err(&ihid->client->dev,
+			"failed to set a report to device: %d\n", error);
+		return error;
+	}
+
+	return data_len;
+}
+
+static int i2c_hid_set_power_command(struct i2c_hid *ihid, int power_state)
+{
+	size_t length;
+
+	guard(mutex)(&ihid->cmd_lock);
+
+	/* SET_POWER uses command register */
+	*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
+	length = sizeof(__le16);
+
+	/* Now the command itself */
+	length += i2c_hid_encode_command(ihid->cmdbuf + length,
+					 I2C_HID_OPCODE_SET_POWER,
+					 0, power_state);
+
+	return i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
+}
+
+static int i2c_hid_set_power(struct i2c_hid *ihid, int power_state)
+{
+	int ret;
+
+	i2c_hid_dbg(ihid, "%s\n", __func__);
+
+	/*
+	 * Some STM-based devices need 400µs after a rising clock edge to wake
+	 * from deep sleep, in which case the first request will fail due to
+	 * the address not being acknowledged. Try after a short sleep to see
+	 * if the device came alive on the bus. Certain Weida Tech devices also
+	 * need this.
+	 */
+	ret = i2c_hid_set_power_command(ihid, power_state);
+	if (ret && power_state == I2C_HID_PWR_ON) {
+		usleep_range(400, 500);
+		ret = i2c_hid_set_power_command(ihid, I2C_HID_PWR_ON);
+	}
+
+	if (ret)
+		dev_err(&ihid->client->dev,
+			"failed to change power setting.\n");
+
+	/*
+	 * The HID over I2C specification states that if a DEVICE needs time
+	 * after the PWR_ON request, it should utilise CLOCK stretching.
+	 * However, it has been observered that the Windows driver provides a
+	 * 1ms sleep between the PWR_ON and RESET requests.
+	 * According to Goodix Windows even waits 60 ms after (other?)
+	 * PWR_ON requests. Testing has confirmed that several devices
+	 * will not work properly without a delay after a PWR_ON request.
+	 */
+	if (!ret && power_state == I2C_HID_PWR_ON)
+		msleep(60);
+
+	return ret;
+}
+
+static int i2c_hid_start_hwreset(struct i2c_hid *ihid)
+{
+	size_t length = 0;
+	int ret;
+
+	i2c_hid_dbg(ihid, "%s\n", __func__);
+
+	/*
+	 * This prevents sending feature reports while the device is
+	 * being reset. Otherwise we may lose the reset complete
+	 * interrupt.
+	 */
+	lockdep_assert_held(&ihid->reset_lock);
+
+	ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
+	if (ret)
+		return ret;
+
+	scoped_guard(mutex, &ihid->cmd_lock) {
+		/* Prepare reset command. Command register goes first. */
+		*(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
+		length += sizeof(__le16);
+		/* Next is RESET command itself */
+		length += i2c_hid_encode_command(ihid->cmdbuf + length,
+						 I2C_HID_OPCODE_RESET, 0, 0);
+
+		set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
+
+		ret = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
+		if (ret) {
+			dev_err(&ihid->client->dev,
+				"failed to reset device: %d\n", ret);
+			break;
+		}
+
+		return 0;
+	}
+
+	/* Clean up if sending reset command failed */
+	clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
+	i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
+	return ret;
+}
+
+static int i2c_hid_finish_hwreset(struct i2c_hid *ihid)
+{
+	int ret = 0;
+
+	i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
+
+	if (ihid->quirks & I2C_HID_QUIRK_NO_IRQ_AFTER_RESET) {
+		msleep(100);
+		clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
+	} else if (!wait_event_timeout(ihid->wait,
+				       !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
+				       msecs_to_jiffies(1000))) {
+		dev_warn(&ihid->client->dev, "device did not ack reset within 1000 ms\n");
+		clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
+	}
+	i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
+
+	/* At least some SIS devices need this after reset */
+	if (!(ihid->quirks & I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET))
+		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
+
+	return ret;
+}
+
+static void i2c_hid_get_input(struct i2c_hid *ihid)
+{
+	u16 size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
+	u16 ret_size;
+	int ret;
+
+	if (size > ihid->bufsize)
+		size = ihid->bufsize;
+
+	ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
+	if (ret != size) {
+		if (ret < 0)
+			return;
+
+		dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
+			__func__, ret, size);
+		return;
+	}
+
+	/* Receiving buffer is properly aligned */
+	ret_size = le16_to_cpup((__le16 *)ihid->inbuf);
+	if (!ret_size) {
+		/* host or device initiated RESET completed */
+		if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
+			wake_up(&ihid->wait);
+		return;
+	}
+
+	if ((ihid->quirks & I2C_HID_QUIRK_BOGUS_IRQ) && ret_size == 0xffff) {
+		dev_warn_once(&ihid->client->dev,
+			      "%s: IRQ triggered but there's no data\n",
+			      __func__);
+		return;
+	}
+
+	if (ret_size > size || ret_size < sizeof(__le16)) {
+		if (ihid->quirks & I2C_HID_QUIRK_BAD_INPUT_SIZE) {
+			*(__le16 *)ihid->inbuf = cpu_to_le16(size);
+			ret_size = size;
+		} else {
+			dev_err(&ihid->client->dev,
+				"%s: incomplete report (%d/%d)\n",
+				__func__, size, ret_size);
+			return;
+		}
+	}
+
+	i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
+
+	if (test_bit(I2C_HID_STARTED, &ihid->flags)) {
+		if (ihid->hid->group != HID_GROUP_RMI)
+			pm_wakeup_event(&ihid->client->dev, 0);
+
+		hid_safe_input_report(ihid->hid, HID_INPUT_REPORT,
+				      ihid->inbuf + sizeof(__le16),
+				      ihid->bufsize - sizeof(__le16),
+				      ret_size - sizeof(__le16), 1);
+	}
+
+	return;
+}
+
+static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
+{
+	struct i2c_hid *ihid = dev_id;
+
+	i2c_hid_get_input(ihid);
+
+	return IRQ_HANDLED;
+}
+
+static int i2c_hid_get_report_length(struct hid_report *report)
+{
+	return ((report->size - 1) >> 3) + 1 +
+		report->device->report_enum[report->type].numbered + 2;
+}
+
+/*
+ * Traverse the supplied list of reports and find the longest
+ */
+static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
+		unsigned int *max)
+{
+	struct hid_report *report;
+	unsigned int size;
+
+	/* We should not rely on wMaxInputLength, as some devices may set it to
+	 * a wrong length. */
+	list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
+		size = i2c_hid_get_report_length(report);
+		if (*max < size)
+			*max = size;
+	}
+}
+
+static void i2c_hid_free_buffers(struct i2c_hid *ihid)
+{
+	kfree(ihid->inbuf);
+	kfree(ihid->rawbuf);
+	kfree(ihid->cmdbuf);
+	ihid->inbuf = NULL;
+	ihid->rawbuf = NULL;
+	ihid->cmdbuf = NULL;
+	ihid->bufsize = 0;
+}
+
+static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
+{
+	/*
+	 * The worst case is computed from the set_report command with a
+	 * reportID > 15 and the maximum report length.
+	 */
+	int cmd_len = sizeof(__le16) +	/* command register */
+		      sizeof(u8) +	/* encoded report type/ID */
+		      sizeof(u8) +	/* opcode */
+		      sizeof(u8) +	/* optional 3rd byte report ID */
+		      sizeof(__le16) +	/* data register */
+		      sizeof(__le16) +	/* report data size */
+		      sizeof(u8) +	/* report ID if numbered report */
+		      report_size;
+
+	ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
+	ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
+	ihid->cmdbuf = kzalloc(cmd_len, GFP_KERNEL);
+
+	if (!ihid->inbuf || !ihid->rawbuf || !ihid->cmdbuf) {
+		i2c_hid_free_buffers(ihid);
+		return -ENOMEM;
+	}
+
+	ihid->bufsize = report_size;
+
+	return 0;
+}
+
+static int i2c_hid_get_raw_report(struct hid_device *hid,
+				  u8 report_type, u8 report_id,
+				  u8 *buf, size_t count)
+{
+	struct i2c_client *client = hid->driver_data;
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	int ret_count;
+
+	if (report_type == HID_OUTPUT_REPORT)
+		return -EINVAL;
+
+	/*
+	 * In case of unnumbered reports the response from the device will
+	 * not have the report ID that the upper layers expect, so we need
+	 * to stash it the buffer ourselves and adjust the data size.
+	 */
+	if (!report_id) {
+		buf[0] = 0;
+		buf++;
+		count--;
+	}
+
+	ret_count = i2c_hid_get_report(ihid,
+			report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
+			report_id, buf, count);
+
+	if (ret_count > 0 && !report_id)
+		ret_count++;
+
+	return ret_count;
+}
+
+static int i2c_hid_output_raw_report(struct hid_device *hid, u8 report_type,
+				     const u8 *buf, size_t count, bool do_set)
+{
+	struct i2c_client *client = hid->driver_data;
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	int report_id = buf[0];
+	int ret;
+
+	if (report_type == HID_INPUT_REPORT)
+		return -EINVAL;
+
+	mutex_lock(&ihid->reset_lock);
+
+	/*
+	 * Note that both numbered and unnumbered reports passed here
+	 * are supposed to have report ID stored in the 1st byte of the
+	 * buffer, so we strip it off unconditionally before passing payload
+	 * to i2c_hid_set_or_send_report which takes care of encoding
+	 * everything properly.
+	 */
+	ret = i2c_hid_set_or_send_report(ihid,
+				report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
+				report_id, buf + 1, count - 1, do_set);
+
+	if (ret >= 0)
+		ret++; /* add report_id to the number of transferred bytes */
+
+	mutex_unlock(&ihid->reset_lock);
+
+	return ret;
+}
+
+static int i2c_hid_output_report(struct hid_device *hid, u8 *buf, size_t count)
+{
+	return i2c_hid_output_raw_report(hid, HID_OUTPUT_REPORT, buf, count,
+					 false);
+}
+
+static int i2c_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
+			       __u8 *buf, size_t len, unsigned char rtype,
+			       int reqtype)
+{
+	switch (reqtype) {
+	case HID_REQ_GET_REPORT:
+		return i2c_hid_get_raw_report(hid, rtype, reportnum, buf, len);
+	case HID_REQ_SET_REPORT:
+		if (buf[0] != reportnum)
+			return -EINVAL;
+		return i2c_hid_output_raw_report(hid, rtype, buf, len, true);
+	default:
+		return -EIO;
+	}
+}
+
+static int i2c_hid_parse(struct hid_device *hid)
+{
+	struct i2c_client *client = hid->driver_data;
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	struct i2c_hid_desc *hdesc = &ihid->hdesc;
+	char *rdesc = NULL, *use_override = NULL;
+	unsigned int rsize;
+	int ret;
+	int tries = 3;
+
+	i2c_hid_dbg(ihid, "entering %s\n", __func__);
+
+	rsize = le16_to_cpu(hdesc->wReportDescLength);
+	if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
+		dbg_hid("weird size of report descriptor (%u)\n", rsize);
+		return -EINVAL;
+	}
+
+	mutex_lock(&ihid->reset_lock);
+	do {
+		ret = i2c_hid_start_hwreset(ihid);
+		if (ret == 0)
+			ret = i2c_hid_finish_hwreset(ihid);
+		else
+			msleep(1000);
+	} while (tries-- > 0 && ret);
+	mutex_unlock(&ihid->reset_lock);
+
+	if (ret)
+		return ret;
+
+	use_override = i2c_hid_get_dmi_hid_report_desc_override(client->name,
+								&rsize);
+
+	if (use_override) {
+		rdesc = use_override;
+		i2c_hid_dbg(ihid, "Using a HID report descriptor override\n");
+	} else {
+		rdesc = kzalloc(rsize, GFP_KERNEL);
+		if (!rdesc)
+			return -ENOMEM;
+
+		i2c_hid_dbg(ihid, "asking HID report descriptor\n");
+
+		ret = i2c_hid_read_register(ihid,
+					    ihid->hdesc.wReportDescRegister,
+					    rdesc, rsize);
+		if (ret) {
+			dev_err(&client->dev, "reading report descriptor failed\n");
+			goto out;
+		}
+	}
+
+	i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
+
+	ret = hid_parse_report(hid, rdesc, rsize);
+	if (ret)
+		dbg_hid("parsing report descriptor failed\n");
+
+out:
+	if (!use_override)
+		kfree(rdesc);
+
+	return ret;
+}
+
+static int i2c_hid_start(struct hid_device *hid)
+{
+	struct i2c_client *client = hid->driver_data;
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	int ret;
+	unsigned int bufsize = HID_MIN_BUFFER_SIZE;
+
+	i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
+	i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
+	i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
+
+	if (bufsize > ihid->bufsize) {
+		disable_irq(client->irq);
+		i2c_hid_free_buffers(ihid);
+
+		ret = i2c_hid_alloc_buffers(ihid, bufsize);
+		enable_irq(client->irq);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void i2c_hid_stop(struct hid_device *hid)
+{
+	hid->claimed = 0;
+}
+
+static int i2c_hid_open(struct hid_device *hid)
+{
+	struct i2c_client *client = hid->driver_data;
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+	set_bit(I2C_HID_STARTED, &ihid->flags);
+	return 0;
+}
+
+static void i2c_hid_close(struct hid_device *hid)
+{
+	struct i2c_client *client = hid->driver_data;
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+	clear_bit(I2C_HID_STARTED, &ihid->flags);
+}
+
+static const struct hid_ll_driver i2c_hid_ll_driver = {
+	.parse = i2c_hid_parse,
+	.start = i2c_hid_start,
+	.stop = i2c_hid_stop,
+	.open = i2c_hid_open,
+	.close = i2c_hid_close,
+	.output_report = i2c_hid_output_report,
+	.raw_request = i2c_hid_raw_request,
+};
+
+static int i2c_hid_init_irq(struct i2c_client *client)
+{
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	unsigned long irqflags = 0;
+	int ret;
+
+	i2c_hid_dbg(ihid, "Requesting IRQ: %d\n", client->irq);
+
+	if (!irq_get_trigger_type(client->irq))
+		irqflags = IRQF_TRIGGER_LOW;
+
+	ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
+				   irqflags | IRQF_ONESHOT | IRQF_NO_AUTOEN,
+				   client->name, ihid);
+	if (ret < 0) {
+		dev_warn(&client->dev,
+			"Could not register for %s interrupt, irq = %d,"
+			" ret = %d\n",
+			client->name, client->irq, ret);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
+{
+	struct i2c_client *client = ihid->client;
+	struct i2c_hid_desc *hdesc = &ihid->hdesc;
+	unsigned int dsize;
+	int error;
+
+	/* i2c hid fetch using a fixed descriptor size (30 bytes) */
+	if (i2c_hid_get_dmi_i2c_hid_desc_override(client->name)) {
+		i2c_hid_dbg(ihid, "Using a HID descriptor override\n");
+		ihid->hdesc =
+			*i2c_hid_get_dmi_i2c_hid_desc_override(client->name);
+	} else {
+		i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
+		error = i2c_hid_read_register(ihid,
+					      ihid->wHIDDescRegister,
+					      &ihid->hdesc,
+					      sizeof(ihid->hdesc));
+		if (error) {
+			dev_err(&ihid->client->dev,
+				"failed to fetch HID descriptor: %d\n",
+				error);
+			return -ENODEV;
+		}
+	}
+
+	/* Validate the length of HID descriptor, the 4 first bytes:
+	 * bytes 0-1 -> length
+	 * bytes 2-3 -> bcdVersion (has to be 1.00) */
+	/* check bcdVersion == 1.0 */
+	if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
+		dev_err(&ihid->client->dev,
+			"unexpected HID descriptor bcdVersion (0x%04hx)\n",
+			le16_to_cpu(hdesc->bcdVersion));
+		return -ENODEV;
+	}
+
+	/* Descriptor length should be 30 bytes as per the specification */
+	dsize = le16_to_cpu(hdesc->wHIDDescLength);
+	if (dsize != sizeof(struct i2c_hid_desc)) {
+		dev_err(&ihid->client->dev,
+			"weird size of HID descriptor (%u)\n", dsize);
+		return -ENODEV;
+	}
+	i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, &ihid->hdesc);
+	return 0;
+}
+
+static int i2c_hid_core_power_up(struct i2c_hid *ihid)
+{
+	if (!ihid->ops->power_up)
+		return 0;
+
+	return ihid->ops->power_up(ihid->ops);
+}
+
+static void i2c_hid_core_power_down(struct i2c_hid *ihid)
+{
+	if (!ihid->ops->power_down)
+		return;
+
+	ihid->ops->power_down(ihid->ops);
+}
+
+static void i2c_hid_core_shutdown_tail(struct i2c_hid *ihid)
+{
+	if (!ihid->ops->shutdown_tail)
+		return;
+
+	ihid->ops->shutdown_tail(ihid->ops);
+}
+
+static void i2c_hid_core_restore_sequence(struct i2c_hid *ihid)
+{
+	if (!ihid->ops->restore_sequence)
+		return;
+
+	ihid->ops->restore_sequence(ihid->ops);
+}
+
+static int i2c_hid_core_suspend(struct i2c_hid *ihid, bool force_poweroff)
+{
+	struct i2c_client *client = ihid->client;
+	struct hid_device *hid = ihid->hid;
+	int ret;
+
+	ret = hid_driver_suspend(hid, PMSG_SUSPEND);
+	if (ret < 0)
+		return ret;
+
+	/* Save some power */
+	if (!(ihid->quirks & I2C_HID_QUIRK_NO_SLEEP_ON_SUSPEND))
+		i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
+
+	disable_irq(client->irq);
+
+	if (force_poweroff || !device_may_wakeup(&client->dev))
+		i2c_hid_core_power_down(ihid);
+
+	return 0;
+}
+
+static int i2c_hid_core_resume(struct i2c_hid *ihid)
+{
+	struct i2c_client *client = ihid->client;
+	struct hid_device *hid = ihid->hid;
+	int ret;
+
+	if (!device_may_wakeup(&client->dev))
+		i2c_hid_core_power_up(ihid);
+
+	enable_irq(client->irq);
+
+	/* On Goodix 27c6:0d42 wait extra time before device wakeup.
+	 * It's not clear why but if we send wakeup too early, the device will
+	 * never trigger input interrupts.
+	 */
+	if (ihid->quirks & I2C_HID_QUIRK_DELAY_WAKEUP_AFTER_RESUME)
+		msleep(1500);
+
+	/* Instead of resetting device, simply powers the device on. This
+	 * solves "incomplete reports" on Raydium devices 2386:3118 and
+	 * 2386:4B33 and fixes various SIS touchscreens no longer sending
+	 * data after a suspend/resume.
+	 *
+	 * However some ALPS touchpads generate IRQ storm without reset, so
+	 * let's still reset them here.
+	 */
+	if (ihid->quirks & I2C_HID_QUIRK_RESET_ON_RESUME) {
+		mutex_lock(&ihid->reset_lock);
+		ret = i2c_hid_start_hwreset(ihid);
+		if (ret == 0)
+			ret = i2c_hid_finish_hwreset(ihid);
+		mutex_unlock(&ihid->reset_lock);
+	} else {
+		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
+	}
+
+	if (ret)
+		return ret;
+
+	return hid_driver_reset_resume(hid);
+}
+
+/*
+ * Check that the device exists and parse the HID descriptor.
+ */
+static int __i2c_hid_core_probe(struct i2c_hid *ihid)
+{
+	struct i2c_client *client = ihid->client;
+	struct hid_device *hid = ihid->hid;
+	int ret;
+
+	ret = i2c_hid_probe_address(ihid);
+	if (ret < 0) {
+		i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret);
+		return -ENXIO;
+	}
+
+	ret = i2c_hid_fetch_hid_descriptor(ihid);
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"Failed to fetch the HID Descriptor\n");
+		return ret;
+	}
+
+	hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
+	hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
+	hid->product = le16_to_cpu(ihid->hdesc.wProductID);
+
+	hid->initial_quirks |= i2c_hid_get_dmi_quirks(hid->vendor,
+						      hid->product);
+
+	snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
+		 client->name, (u16)hid->vendor, (u16)hid->product);
+	strscpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
+
+	ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);
+
+	return 0;
+}
+
+static int i2c_hid_core_register_hid(struct i2c_hid *ihid)
+{
+	struct i2c_client *client = ihid->client;
+	struct hid_device *hid = ihid->hid;
+	int ret;
+
+	enable_irq(client->irq);
+
+	ret = hid_add_device(hid);
+	if (ret) {
+		if (ret != -ENODEV)
+			hid_err(client, "can't add hid device: %d\n", ret);
+		disable_irq(client->irq);
+		return ret;
+	}
+
+	/* At least some QTEC devices need this after initialization */
+	if (ihid->quirks & I2C_HID_QUIRK_RE_POWER_ON)
+		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
+
+	return ret;
+}
+
+static int i2c_hid_core_probe_panel_follower(struct i2c_hid *ihid)
+{
+	int ret;
+
+	ret = i2c_hid_core_power_up(ihid);
+	if (ret)
+		return ret;
+
+	ret = __i2c_hid_core_probe(ihid);
+	if (ret)
+		goto err_power_down;
+
+	ret = i2c_hid_core_register_hid(ihid);
+	if (ret)
+		goto err_power_down;
+
+	return 0;
+
+err_power_down:
+	i2c_hid_core_power_down(ihid);
+
+	return ret;
+}
+
+static void ihid_core_panel_follower_work(struct work_struct *work)
+{
+	struct i2c_hid *ihid = container_of(work, struct i2c_hid,
+					    panel_follower_work);
+	struct hid_device *hid = ihid->hid;
+	int ret;
+
+	/*
+	 * hid->version is set on the first power up. If it's still zero then
+	 * this is the first power on so we should perform initial power up
+	 * steps.
+	 */
+	if (!hid->version)
+		ret = i2c_hid_core_probe_panel_follower(ihid);
+	else
+		ret = i2c_hid_core_resume(ihid);
+
+	if (ret)
+		dev_warn(&ihid->client->dev, "Power on failed: %d\n", ret);
+	else
+		WRITE_ONCE(ihid->panel_follower_work_finished, true);
+
+	/*
+	 * The work APIs provide a number of memory ordering guarantees
+	 * including one that says that memory writes before schedule_work()
+	 * are always visible to the work function, but they don't appear to
+	 * guarantee that a write that happened in the work is visible after
+	 * cancel_work_sync(). We'll add a write memory barrier here to match
+	 * with i2c_hid_core_panel_unpreparing() to ensure that our write to
+	 * panel_follower_work_finished is visible there.
+	 */
+	smp_wmb();
+}
+
+static int i2c_hid_core_panel_follower_resume(struct drm_panel_follower *follower)
+{
+	struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
+
+	/*
+	 * Powering on a touchscreen can be a slow process. Queue the work to
+	 * the system workqueue so we don't block the panel's power up.
+	 */
+	WRITE_ONCE(ihid->panel_follower_work_finished, false);
+	schedule_work(&ihid->panel_follower_work);
+
+	return 0;
+}
+
+static int i2c_hid_core_panel_follower_suspend(struct drm_panel_follower *follower)
+{
+	struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
+
+	cancel_work_sync(&ihid->panel_follower_work);
+
+	/* Match with ihid_core_panel_follower_work() */
+	smp_rmb();
+	if (!READ_ONCE(ihid->panel_follower_work_finished))
+		return 0;
+
+	return i2c_hid_core_suspend(ihid, true);
+}
+
+static const struct drm_panel_follower_funcs
+				i2c_hid_core_panel_follower_prepare_funcs = {
+	.panel_prepared = i2c_hid_core_panel_follower_resume,
+	.panel_unpreparing = i2c_hid_core_panel_follower_suspend,
+};
+
+static const struct drm_panel_follower_funcs
+				i2c_hid_core_panel_follower_enable_funcs = {
+	.panel_enabled = i2c_hid_core_panel_follower_resume,
+	.panel_disabling = i2c_hid_core_panel_follower_suspend,
+};
+
+static int i2c_hid_core_register_panel_follower(struct i2c_hid *ihid)
+{
+	struct device *dev = &ihid->client->dev;
+	int ret;
+
+	if (ihid->hid->initial_quirks & HID_QUIRK_POWER_ON_AFTER_BACKLIGHT)
+		ihid->panel_follower.funcs = &i2c_hid_core_panel_follower_enable_funcs;
+	else
+		ihid->panel_follower.funcs = &i2c_hid_core_panel_follower_prepare_funcs;
+
+	/*
+	 * If we're not in control of our own power up/power down then we can't
+	 * do the logic to manage wakeups. Give a warning if a user thought
+	 * that was possible then force the capability off.
+	 */
+	if (device_can_wakeup(dev)) {
+		dev_warn(dev, "Can't wakeup if following panel\n");
+		device_set_wakeup_capable(dev, false);
+	}
+
+	ret = drm_panel_add_follower(dev, &ihid->panel_follower);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
+		       u16 hid_descriptor_address, u32 quirks)
+{
+	int ret;
+	struct i2c_hid *ihid;
+	struct hid_device *hid;
+
+	dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
+
+	if (!client->irq) {
+		dev_err(&client->dev,
+			"HID over i2c has not been provided an Int IRQ\n");
+		return -EINVAL;
+	}
+
+	if (client->irq < 0) {
+		if (client->irq != -EPROBE_DEFER)
+			dev_err(&client->dev,
+				"HID over i2c doesn't have a valid IRQ\n");
+		return client->irq;
+	}
+
+	ihid = devm_kzalloc(&client->dev, sizeof(*ihid), GFP_KERNEL);
+	if (!ihid)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, ihid);
+
+	ihid->ops = ops;
+	ihid->client = client;
+	ihid->wHIDDescRegister = cpu_to_le16(hid_descriptor_address);
+	ihid->is_panel_follower = drm_is_panel_follower(&client->dev);
+
+	init_waitqueue_head(&ihid->wait);
+	mutex_init(&ihid->cmd_lock);
+	mutex_init(&ihid->reset_lock);
+	INIT_WORK(&ihid->panel_follower_work, ihid_core_panel_follower_work);
+
+	/* we need to allocate the command buffer without knowing the maximum
+	 * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
+	 * real computation later. */
+	ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
+	if (ret < 0)
+		return ret;
+	device_enable_async_suspend(&client->dev);
+
+	hid = hid_allocate_device();
+	if (IS_ERR(hid)) {
+		ret = PTR_ERR(hid);
+		goto err_free_buffers;
+	}
+
+	ihid->hid = hid;
+
+	hid->driver_data = client;
+	hid->ll_driver = &i2c_hid_ll_driver;
+	hid->dev.parent = &client->dev;
+	hid->bus = BUS_I2C;
+	hid->initial_quirks = quirks;
+
+	/* Power on and probe unless device is a panel follower. */
+	if (!ihid->is_panel_follower) {
+		ret = i2c_hid_core_power_up(ihid);
+		if (ret < 0)
+			goto err_destroy_device;
+
+		ret = __i2c_hid_core_probe(ihid);
+		if (ret < 0)
+			goto err_power_down;
+	}
+
+	ret = i2c_hid_init_irq(client);
+	if (ret < 0)
+		goto err_power_down;
+
+	/*
+	 * If we're a panel follower, we'll register when the panel turns on;
+	 * otherwise we do it right away.
+	 */
+	if (ihid->is_panel_follower)
+		ret = i2c_hid_core_register_panel_follower(ihid);
+	else
+		ret = i2c_hid_core_register_hid(ihid);
+	if (ret)
+		goto err_free_irq;
+
+	return 0;
+
+err_free_irq:
+	free_irq(client->irq, ihid);
+err_power_down:
+	if (!ihid->is_panel_follower)
+		i2c_hid_core_power_down(ihid);
+err_destroy_device:
+	hid_destroy_device(hid);
+err_free_buffers:
+	i2c_hid_free_buffers(ihid);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(i2c_hid_core_probe);
+
+void i2c_hid_core_remove(struct i2c_client *client)
+{
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	struct hid_device *hid;
+
+	/*
+	 * If we're a follower, the act of unfollowing will cause us to be
+	 * powered down. Otherwise we need to manually do it.
+	 */
+	if (ihid->is_panel_follower)
+		drm_panel_remove_follower(&ihid->panel_follower);
+	else
+		i2c_hid_core_suspend(ihid, true);
+
+	hid = ihid->hid;
+	hid_destroy_device(hid);
+
+	free_irq(client->irq, ihid);
+
+	if (ihid->bufsize)
+		i2c_hid_free_buffers(ihid);
+}
+EXPORT_SYMBOL_GPL(i2c_hid_core_remove);
+
+void i2c_hid_core_shutdown(struct i2c_client *client)
+{
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+	i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
+	free_irq(client->irq, ihid);
+
+	i2c_hid_core_shutdown_tail(ihid);
+}
+EXPORT_SYMBOL_GPL(i2c_hid_core_shutdown);
+
+static int i2c_hid_core_pm_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+	if (ihid->is_panel_follower)
+		return 0;
+
+	return i2c_hid_core_suspend(ihid, false);
+}
+
+static int i2c_hid_core_pm_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+	if (ihid->is_panel_follower)
+		return 0;
+
+	return i2c_hid_core_resume(ihid);
+}
+
+static int i2c_hid_core_pm_restore(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+	if (ihid->is_panel_follower)
+		return 0;
+
+	i2c_hid_core_restore_sequence(ihid);
+
+	return i2c_hid_core_resume(ihid);
+}
+
+const struct dev_pm_ops i2c_hid_core_pm = {
+	.suspend = pm_sleep_ptr(i2c_hid_core_pm_suspend),
+	.resume = pm_sleep_ptr(i2c_hid_core_pm_resume),
+	.freeze = pm_sleep_ptr(i2c_hid_core_pm_suspend),
+	.thaw = pm_sleep_ptr(i2c_hid_core_pm_resume),
+	.poweroff = pm_sleep_ptr(i2c_hid_core_pm_suspend),
+	.restore = pm_sleep_ptr(i2c_hid_core_pm_restore),
+};
+EXPORT_SYMBOL_GPL(i2c_hid_core_pm);
+
+MODULE_DESCRIPTION("HID over I2C core driver");
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/i2c-hid/i2c-hid-dmi-quirks.c b/drivers/hid/i2c-hid/i2c-hid-dmi-quirks.c
new file mode 100644
index 000000000..83b9bc4b0
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-dmi-quirks.c
@@ -0,0 +1,493 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Quirks for I2C-HID devices that do not supply proper descriptors
+ *
+ * Copyright (c) 2018 Julian Sax <jsbc@gmx.de>
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/dmi.h>
+#include <linux/hid.h>
+
+#include "i2c-hid.h"
+#include "../hid-ids.h"
+
+
+struct i2c_hid_desc_override {
+	union {
+		struct i2c_hid_desc *i2c_hid_desc;
+		uint8_t             *i2c_hid_desc_buffer;
+	};
+	uint8_t              *hid_report_desc;
+	unsigned int          hid_report_desc_size;
+	uint8_t              *i2c_name;
+};
+
+
+/*
+ * descriptors for the SIPODEV SP1064 touchpad
+ *
+ * This device does not supply any descriptors and on windows a filter
+ * driver operates between the i2c-hid layer and the device and injects
+ * these descriptors when the device is prompted. The descriptors were
+ * extracted by listening to the i2c-hid traffic that occurs between the
+ * windows filter driver and the windows i2c-hid driver.
+ */
+
+static const struct i2c_hid_desc_override sipodev_desc = {
+	.i2c_hid_desc_buffer = (uint8_t [])
+	{0x1e, 0x00,                  /* Length of descriptor                 */
+	 0x00, 0x01,                  /* Version of descriptor                */
+	 0xdb, 0x01,                  /* Length of report descriptor          */
+	 0x21, 0x00,                  /* Location of report descriptor        */
+	 0x24, 0x00,                  /* Location of input report             */
+	 0x1b, 0x00,                  /* Max input report length              */
+	 0x25, 0x00,                  /* Location of output report            */
+	 0x11, 0x00,                  /* Max output report length             */
+	 0x22, 0x00,                  /* Location of command register         */
+	 0x23, 0x00,                  /* Location of data register            */
+	 0x11, 0x09,                  /* Vendor ID                            */
+	 0x88, 0x52,                  /* Product ID                           */
+	 0x06, 0x00,                  /* Version ID                           */
+	 0x00, 0x00, 0x00, 0x00       /* Reserved                             */
+	},
+
+	.hid_report_desc = (uint8_t [])
+	{0x05, 0x01,                  /* Usage Page (Desktop),                */
+	 0x09, 0x02,                  /* Usage (Mouse),                       */
+	 0xA1, 0x01,                  /* Collection (Application),            */
+	 0x85, 0x01,                  /*     Report ID (1),                   */
+	 0x09, 0x01,                  /*     Usage (Pointer),                 */
+	 0xA1, 0x00,                  /*     Collection (Physical),           */
+	 0x05, 0x09,                  /*         Usage Page (Button),         */
+	 0x19, 0x01,                  /*         Usage Minimum (01h),         */
+	 0x29, 0x02,                  /*         Usage Maximum (02h),         */
+	 0x25, 0x01,                  /*         Logical Maximum (1),         */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x95, 0x02,                  /*         Report Count (2),            */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x95, 0x06,                  /*         Report Count (6),            */
+	 0x81, 0x01,                  /*         Input (Constant),            */
+	 0x05, 0x01,                  /*         Usage Page (Desktop),        */
+	 0x09, 0x30,                  /*         Usage (X),                   */
+	 0x09, 0x31,                  /*         Usage (Y),                   */
+	 0x15, 0x81,                  /*         Logical Minimum (-127),      */
+	 0x25, 0x7F,                  /*         Logical Maximum (127),       */
+	 0x75, 0x08,                  /*         Report Size (8),             */
+	 0x95, 0x02,                  /*         Report Count (2),            */
+	 0x81, 0x06,                  /*         Input (Variable, Relative),  */
+	 0xC0,                        /*     End Collection,                  */
+	 0xC0,                        /* End Collection,                      */
+	 0x05, 0x0D,                  /* Usage Page (Digitizer),              */
+	 0x09, 0x05,                  /* Usage (Touchpad),                    */
+	 0xA1, 0x01,                  /* Collection (Application),            */
+	 0x85, 0x04,                  /*     Report ID (4),                   */
+	 0x05, 0x0D,                  /*     Usage Page (Digitizer),          */
+	 0x09, 0x22,                  /*     Usage (Finger),                  */
+	 0xA1, 0x02,                  /*     Collection (Logical),            */
+	 0x15, 0x00,                  /*         Logical Minimum (0),         */
+	 0x25, 0x01,                  /*         Logical Maximum (1),         */
+	 0x09, 0x47,                  /*         Usage (Touch Valid),         */
+	 0x09, 0x42,                  /*         Usage (Tip Switch),          */
+	 0x95, 0x02,                  /*         Report Count (2),            */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0x75, 0x03,                  /*         Report Size (3),             */
+	 0x25, 0x05,                  /*         Logical Maximum (5),         */
+	 0x09, 0x51,                  /*         Usage (Contact Identifier),  */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x95, 0x03,                  /*         Report Count (3),            */
+	 0x81, 0x03,                  /*         Input (Constant, Variable),  */
+	 0x05, 0x01,                  /*         Usage Page (Desktop),        */
+	 0x26, 0x44, 0x0A,            /*         Logical Maximum (2628),      */
+	 0x75, 0x10,                  /*         Report Size (16),            */
+	 0x55, 0x0E,                  /*         Unit Exponent (14),          */
+	 0x65, 0x11,                  /*         Unit (Centimeter),           */
+	 0x09, 0x30,                  /*         Usage (X),                   */
+	 0x46, 0x1A, 0x04,            /*         Physical Maximum (1050),     */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x46, 0xBC, 0x02,            /*         Physical Maximum (700),      */
+	 0x26, 0x34, 0x05,            /*         Logical Maximum (1332),      */
+	 0x09, 0x31,                  /*         Usage (Y),                   */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0xC0,                        /*     End Collection,                  */
+	 0x05, 0x0D,                  /*     Usage Page (Digitizer),          */
+	 0x09, 0x22,                  /*     Usage (Finger),                  */
+	 0xA1, 0x02,                  /*     Collection (Logical),            */
+	 0x25, 0x01,                  /*         Logical Maximum (1),         */
+	 0x09, 0x47,                  /*         Usage (Touch Valid),         */
+	 0x09, 0x42,                  /*         Usage (Tip Switch),          */
+	 0x95, 0x02,                  /*         Report Count (2),            */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0x75, 0x03,                  /*         Report Size (3),             */
+	 0x25, 0x05,                  /*         Logical Maximum (5),         */
+	 0x09, 0x51,                  /*         Usage (Contact Identifier),  */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x95, 0x03,                  /*         Report Count (3),            */
+	 0x81, 0x03,                  /*         Input (Constant, Variable),  */
+	 0x05, 0x01,                  /*         Usage Page (Desktop),        */
+	 0x26, 0x44, 0x0A,            /*         Logical Maximum (2628),      */
+	 0x75, 0x10,                  /*         Report Size (16),            */
+	 0x09, 0x30,                  /*         Usage (X),                   */
+	 0x46, 0x1A, 0x04,            /*         Physical Maximum (1050),     */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x46, 0xBC, 0x02,            /*         Physical Maximum (700),      */
+	 0x26, 0x34, 0x05,            /*         Logical Maximum (1332),      */
+	 0x09, 0x31,                  /*         Usage (Y),                   */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0xC0,                        /*     End Collection,                  */
+	 0x05, 0x0D,                  /*     Usage Page (Digitizer),          */
+	 0x09, 0x22,                  /*     Usage (Finger),                  */
+	 0xA1, 0x02,                  /*     Collection (Logical),            */
+	 0x25, 0x01,                  /*         Logical Maximum (1),         */
+	 0x09, 0x47,                  /*         Usage (Touch Valid),         */
+	 0x09, 0x42,                  /*         Usage (Tip Switch),          */
+	 0x95, 0x02,                  /*         Report Count (2),            */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0x75, 0x03,                  /*         Report Size (3),             */
+	 0x25, 0x05,                  /*         Logical Maximum (5),         */
+	 0x09, 0x51,                  /*         Usage (Contact Identifier),  */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x95, 0x03,                  /*         Report Count (3),            */
+	 0x81, 0x03,                  /*         Input (Constant, Variable),  */
+	 0x05, 0x01,                  /*         Usage Page (Desktop),        */
+	 0x26, 0x44, 0x0A,            /*         Logical Maximum (2628),      */
+	 0x75, 0x10,                  /*         Report Size (16),            */
+	 0x09, 0x30,                  /*         Usage (X),                   */
+	 0x46, 0x1A, 0x04,            /*         Physical Maximum (1050),     */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x46, 0xBC, 0x02,            /*         Physical Maximum (700),      */
+	 0x26, 0x34, 0x05,            /*         Logical Maximum (1332),      */
+	 0x09, 0x31,                  /*         Usage (Y),                   */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0xC0,                        /*     End Collection,                  */
+	 0x05, 0x0D,                  /*     Usage Page (Digitizer),          */
+	 0x09, 0x22,                  /*     Usage (Finger),                  */
+	 0xA1, 0x02,                  /*     Collection (Logical),            */
+	 0x25, 0x01,                  /*         Logical Maximum (1),         */
+	 0x09, 0x47,                  /*         Usage (Touch Valid),         */
+	 0x09, 0x42,                  /*         Usage (Tip Switch),          */
+	 0x95, 0x02,                  /*         Report Count (2),            */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0x75, 0x03,                  /*         Report Size (3),             */
+	 0x25, 0x05,                  /*         Logical Maximum (5),         */
+	 0x09, 0x51,                  /*         Usage (Contact Identifier),  */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x95, 0x03,                  /*         Report Count (3),            */
+	 0x81, 0x03,                  /*         Input (Constant, Variable),  */
+	 0x05, 0x01,                  /*         Usage Page (Desktop),        */
+	 0x26, 0x44, 0x0A,            /*         Logical Maximum (2628),      */
+	 0x75, 0x10,                  /*         Report Size (16),            */
+	 0x09, 0x30,                  /*         Usage (X),                   */
+	 0x46, 0x1A, 0x04,            /*         Physical Maximum (1050),     */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0x46, 0xBC, 0x02,            /*         Physical Maximum (700),      */
+	 0x26, 0x34, 0x05,            /*         Logical Maximum (1332),      */
+	 0x09, 0x31,                  /*         Usage (Y),                   */
+	 0x81, 0x02,                  /*         Input (Variable),            */
+	 0xC0,                        /*     End Collection,                  */
+	 0x05, 0x0D,                  /*     Usage Page (Digitizer),          */
+	 0x55, 0x0C,                  /*     Unit Exponent (12),              */
+	 0x66, 0x01, 0x10,            /*     Unit (Seconds),                  */
+	 0x47, 0xFF, 0xFF, 0x00, 0x00,/*     Physical Maximum (65535),        */
+	 0x27, 0xFF, 0xFF, 0x00, 0x00,/*     Logical Maximum (65535),         */
+	 0x75, 0x10,                  /*     Report Size (16),                */
+	 0x95, 0x01,                  /*     Report Count (1),                */
+	 0x09, 0x56,                  /*     Usage (Scan Time),               */
+	 0x81, 0x02,                  /*     Input (Variable),                */
+	 0x09, 0x54,                  /*     Usage (Contact Count),           */
+	 0x25, 0x7F,                  /*     Logical Maximum (127),           */
+	 0x75, 0x08,                  /*     Report Size (8),                 */
+	 0x81, 0x02,                  /*     Input (Variable),                */
+	 0x05, 0x09,                  /*     Usage Page (Button),             */
+	 0x09, 0x01,                  /*     Usage (01h),                     */
+	 0x25, 0x01,                  /*     Logical Maximum (1),             */
+	 0x75, 0x01,                  /*     Report Size (1),                 */
+	 0x95, 0x01,                  /*     Report Count (1),                */
+	 0x81, 0x02,                  /*     Input (Variable),                */
+	 0x95, 0x07,                  /*     Report Count (7),                */
+	 0x81, 0x03,                  /*     Input (Constant, Variable),      */
+	 0x05, 0x0D,                  /*     Usage Page (Digitizer),          */
+	 0x85, 0x02,                  /*     Report ID (2),                   */
+	 0x09, 0x55,                  /*     Usage (Contact Count Maximum),   */
+	 0x09, 0x59,                  /*     Usage (59h),                     */
+	 0x75, 0x04,                  /*     Report Size (4),                 */
+	 0x95, 0x02,                  /*     Report Count (2),                */
+	 0x25, 0x0F,                  /*     Logical Maximum (15),            */
+	 0xB1, 0x02,                  /*     Feature (Variable),              */
+	 0x05, 0x0D,                  /*     Usage Page (Digitizer),          */
+	 0x85, 0x07,                  /*     Report ID (7),                   */
+	 0x09, 0x60,                  /*     Usage (60h),                     */
+	 0x75, 0x01,                  /*     Report Size (1),                 */
+	 0x95, 0x01,                  /*     Report Count (1),                */
+	 0x25, 0x01,                  /*     Logical Maximum (1),             */
+	 0xB1, 0x02,                  /*     Feature (Variable),              */
+	 0x95, 0x07,                  /*     Report Count (7),                */
+	 0xB1, 0x03,                  /*     Feature (Constant, Variable),    */
+	 0x85, 0x06,                  /*     Report ID (6),                   */
+	 0x06, 0x00, 0xFF,            /*     Usage Page (FF00h),              */
+	 0x09, 0xC5,                  /*     Usage (C5h),                     */
+	 0x26, 0xFF, 0x00,            /*     Logical Maximum (255),           */
+	 0x75, 0x08,                  /*     Report Size (8),                 */
+	 0x96, 0x00, 0x01,            /*     Report Count (256),              */
+	 0xB1, 0x02,                  /*     Feature (Variable),              */
+	 0xC0,                        /* End Collection,                      */
+	 0x06, 0x00, 0xFF,            /* Usage Page (FF00h),                  */
+	 0x09, 0x01,                  /* Usage (01h),                         */
+	 0xA1, 0x01,                  /* Collection (Application),            */
+	 0x85, 0x0D,                  /*     Report ID (13),                  */
+	 0x26, 0xFF, 0x00,            /*     Logical Maximum (255),           */
+	 0x19, 0x01,                  /*     Usage Minimum (01h),             */
+	 0x29, 0x02,                  /*     Usage Maximum (02h),             */
+	 0x75, 0x08,                  /*     Report Size (8),                 */
+	 0x95, 0x02,                  /*     Report Count (2),                */
+	 0xB1, 0x02,                  /*     Feature (Variable),              */
+	 0xC0,                        /* End Collection,                      */
+	 0x05, 0x0D,                  /* Usage Page (Digitizer),              */
+	 0x09, 0x0E,                  /* Usage (Configuration),               */
+	 0xA1, 0x01,                  /* Collection (Application),            */
+	 0x85, 0x03,                  /*     Report ID (3),                   */
+	 0x09, 0x22,                  /*     Usage (Finger),                  */
+	 0xA1, 0x02,                  /*     Collection (Logical),            */
+	 0x09, 0x52,                  /*         Usage (Device Mode),         */
+	 0x25, 0x0A,                  /*         Logical Maximum (10),        */
+	 0x95, 0x01,                  /*         Report Count (1),            */
+	 0xB1, 0x02,                  /*         Feature (Variable),          */
+	 0xC0,                        /*     End Collection,                  */
+	 0x09, 0x22,                  /*     Usage (Finger),                  */
+	 0xA1, 0x00,                  /*     Collection (Physical),           */
+	 0x85, 0x05,                  /*         Report ID (5),               */
+	 0x09, 0x57,                  /*         Usage (57h),                 */
+	 0x09, 0x58,                  /*         Usage (58h),                 */
+	 0x75, 0x01,                  /*         Report Size (1),             */
+	 0x95, 0x02,                  /*         Report Count (2),            */
+	 0x25, 0x01,                  /*         Logical Maximum (1),         */
+	 0xB1, 0x02,                  /*         Feature (Variable),          */
+	 0x95, 0x06,                  /*         Report Count (6),            */
+	 0xB1, 0x03,                  /*         Feature (Constant, Variable),*/
+	 0xC0,                        /*     End Collection,                  */
+	 0xC0                         /* End Collection                       */
+	},
+	.hid_report_desc_size = 475,
+	.i2c_name = "SYNA3602:00"
+};
+
+
+static const struct dmi_system_id i2c_hid_dmi_desc_override_table[] = {
+	{
+		.ident = "Teclast F6 Pro",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "TECLAST"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "F6 Pro"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Teclast F7",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "TECLAST"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "F7"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Trekstor Primebook C13",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "TREKSTOR"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Primebook C13"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Trekstor Primebook C11",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "TREKSTOR"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Primebook C11"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		/*
+		 * There are at least 2 Primebook C11B versions, the older
+		 * version has a product-name of "Primebook C11B", and a
+		 * bios version / release / firmware revision of:
+		 * V2.1.2 / 05/03/2018 / 18.2
+		 * The new version has "PRIMEBOOK C11B" as product-name and a
+		 * bios version / release / firmware revision of:
+		 * CFALKSW05_BIOS_V1.1.2 / 11/19/2018 / 19.2
+		 * Only the older version needs this quirk, note the newer
+		 * version will not match as it has a different product-name.
+		 */
+		.ident = "Trekstor Primebook C11B",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "TREKSTOR"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Primebook C11B"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Trekstor SURFBOOK E11B",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "TREKSTOR"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "SURFBOOK E11B"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Direkt-Tek DTLAPY116-2",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Direkt-Tek"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "DTLAPY116-2"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Direkt-Tek DTLAPY133-1",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Direkt-Tek"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "DTLAPY133-1"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Mediacom Flexbook Edge 11",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "MEDIACOM"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "FlexBook edge11 - M-FBE11"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Mediacom FlexBook edge 13",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "MEDIACOM"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "FlexBook_edge13-M-FBE13"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Odys Winbook 13",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "AXDIA International GmbH"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "WINBOOK 13"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "iBall Aer3",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "iBall"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Aer3"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Schneider SCL142ALM",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "SCHNEIDER"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "SCL142ALM"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{
+		.ident = "Vero K147",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "VERO"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "K147"),
+		},
+		.driver_data = (void *)&sipodev_desc
+	},
+	{ }	/* Terminate list */
+};
+
+static const struct hid_device_id i2c_hid_elan_flipped_quirks = {
+	HID_DEVICE(BUS_I2C, HID_GROUP_MULTITOUCH_WIN_8, USB_VENDOR_ID_ELAN, 0x2dcd),
+		HID_QUIRK_X_INVERT | HID_QUIRK_Y_INVERT
+};
+
+/*
+ * This list contains devices which have specific issues based on the system
+ * they're on and not just the device itself. The driver_data will have a
+ * specific hid device to match against.
+ */
+static const struct dmi_system_id i2c_hid_dmi_quirk_table[] = {
+	{
+		.ident = "DynaBook K50/FR",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dynabook Inc."),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "dynabook K50/FR"),
+		},
+		.driver_data = (void *)&i2c_hid_elan_flipped_quirks,
+	},
+	{ }	/* Terminate list */
+};
+
+
+struct i2c_hid_desc *i2c_hid_get_dmi_i2c_hid_desc_override(uint8_t *i2c_name)
+{
+	struct i2c_hid_desc_override *override;
+	const struct dmi_system_id *system_id;
+
+	system_id = dmi_first_match(i2c_hid_dmi_desc_override_table);
+	if (!system_id)
+		return NULL;
+
+	override = system_id->driver_data;
+	if (strcmp(override->i2c_name, i2c_name))
+		return NULL;
+
+	return override->i2c_hid_desc;
+}
+
+char *i2c_hid_get_dmi_hid_report_desc_override(uint8_t *i2c_name,
+					       unsigned int *size)
+{
+	struct i2c_hid_desc_override *override;
+	const struct dmi_system_id *system_id;
+
+	system_id = dmi_first_match(i2c_hid_dmi_desc_override_table);
+	if (!system_id)
+		return NULL;
+
+	override = system_id->driver_data;
+	if (strcmp(override->i2c_name, i2c_name))
+		return NULL;
+
+	*size = override->hid_report_desc_size;
+	return override->hid_report_desc;
+}
+
+u32 i2c_hid_get_dmi_quirks(const u16 vendor, const u16 product)
+{
+	u32 quirks = 0;
+	const struct dmi_system_id *system_id =
+			dmi_first_match(i2c_hid_dmi_quirk_table);
+
+	if (system_id) {
+		const struct hid_device_id *device_id =
+				(struct hid_device_id *)(system_id->driver_data);
+
+		if (device_id && device_id->vendor == vendor &&
+		    device_id->product == product)
+			quirks = device_id->driver_data;
+	}
+
+	return quirks;
+}
diff --git a/drivers/hid/i2c-hid/i2c-hid-of-elan.c b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
new file mode 100644
index 000000000..919e32c47
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Elan touchscreens that use the i2c-hid protocol.
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/hid.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+
+#include "i2c-hid.h"
+
+struct elan_i2c_hid_chip_data {
+	unsigned int post_gpio_reset_on_delay_ms;
+	unsigned int post_gpio_reset_off_delay_ms;
+	unsigned int post_power_delay_ms;
+	u16 hid_descriptor_address;
+	const char *main_supply_name;
+	bool power_after_backlight;
+};
+
+struct i2c_hid_of_elan {
+	struct i2chid_ops ops;
+
+	struct regulator *vcc33;
+	struct regulator *vccio;
+	struct gpio_desc *reset_gpio;
+	bool no_reset_on_power_off;
+	const struct elan_i2c_hid_chip_data *chip_data;
+};
+
+static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
+{
+	struct i2c_hid_of_elan *ihid_elan =
+		container_of(ops, struct i2c_hid_of_elan, ops);
+	int ret;
+
+	gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
+
+	if (ihid_elan->vcc33) {
+		ret = regulator_enable(ihid_elan->vcc33);
+		if (ret)
+			goto err_deassert_reset;
+	}
+
+	ret = regulator_enable(ihid_elan->vccio);
+	if (ret)
+		goto err_disable_vcc33;
+
+	if (ihid_elan->chip_data->post_power_delay_ms)
+		msleep(ihid_elan->chip_data->post_power_delay_ms);
+
+	gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
+	if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms)
+		msleep(ihid_elan->chip_data->post_gpio_reset_on_delay_ms);
+
+	return 0;
+
+err_disable_vcc33:
+	if (ihid_elan->vcc33)
+		regulator_disable(ihid_elan->vcc33);
+err_deassert_reset:
+	if (ihid_elan->no_reset_on_power_off)
+		gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
+
+	return ret;
+}
+
+static void elan_i2c_hid_power_down(struct i2chid_ops *ops)
+{
+	struct i2c_hid_of_elan *ihid_elan =
+		container_of(ops, struct i2c_hid_of_elan, ops);
+
+	/*
+	 * Do not assert reset when the hardware allows for it to remain
+	 * deasserted regardless of the state of the (shared) power supply to
+	 * avoid wasting power when the supply is left on.
+	 */
+	if (!ihid_elan->no_reset_on_power_off)
+		gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
+
+	if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms)
+		msleep(ihid_elan->chip_data->post_gpio_reset_off_delay_ms);
+
+	regulator_disable(ihid_elan->vccio);
+	if (ihid_elan->vcc33)
+		regulator_disable(ihid_elan->vcc33);
+}
+
+static int i2c_hid_of_elan_probe(struct i2c_client *client)
+{
+	struct i2c_hid_of_elan *ihid_elan;
+	int ret;
+	u32 quirks = 0;
+
+	ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL);
+	if (!ihid_elan)
+		return -ENOMEM;
+
+	ihid_elan->ops.power_up = elan_i2c_hid_power_up;
+	ihid_elan->ops.power_down = elan_i2c_hid_power_down;
+
+	/* Start out with reset asserted */
+	ihid_elan->reset_gpio =
+		devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ihid_elan->reset_gpio))
+		return PTR_ERR(ihid_elan->reset_gpio);
+
+	ihid_elan->no_reset_on_power_off = of_property_read_bool(client->dev.of_node,
+						"no-reset-on-power-off");
+
+	ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio");
+	if (IS_ERR(ihid_elan->vccio)) {
+		ret = PTR_ERR(ihid_elan->vccio);
+		goto err_deassert_reset;
+	}
+
+	ihid_elan->chip_data = device_get_match_data(&client->dev);
+
+	if (ihid_elan->chip_data->main_supply_name) {
+		ihid_elan->vcc33 = devm_regulator_get(&client->dev,
+						      ihid_elan->chip_data->main_supply_name);
+		if (IS_ERR(ihid_elan->vcc33)) {
+			ret = PTR_ERR(ihid_elan->vcc33);
+			goto err_deassert_reset;
+		}
+	}
+
+	if (ihid_elan->chip_data->power_after_backlight)
+		quirks = HID_QUIRK_POWER_ON_AFTER_BACKLIGHT;
+
+	ret = i2c_hid_core_probe(client, &ihid_elan->ops,
+				 ihid_elan->chip_data->hid_descriptor_address,
+				 quirks);
+	if (ret)
+		goto err_deassert_reset;
+
+	return 0;
+
+err_deassert_reset:
+	if (ihid_elan->no_reset_on_power_off)
+		gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
+
+	return ret;
+}
+
+static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {
+	.post_power_delay_ms = 1,
+	.post_gpio_reset_on_delay_ms = 300,
+	.hid_descriptor_address = 0x0001,
+	.main_supply_name = "vcc33",
+	.power_after_backlight = true,
+};
+
+static const struct elan_i2c_hid_chip_data elan_ekth6a12nay_chip_data = {
+	.post_power_delay_ms = 10,
+	.post_gpio_reset_on_delay_ms = 300,
+	.hid_descriptor_address = 0x0001,
+	.main_supply_name = "vcc33",
+	.power_after_backlight = true,
+};
+
+static const struct elan_i2c_hid_chip_data focaltech_ft8112_chip_data = {
+	.post_power_delay_ms = 10,
+	.post_gpio_reset_on_delay_ms = 150,
+	.hid_descriptor_address = 0x0001,
+	.main_supply_name = "vcc33",
+};
+
+static const struct elan_i2c_hid_chip_data ilitek_ili9882t_chip_data = {
+	.post_power_delay_ms = 1,
+	.post_gpio_reset_on_delay_ms = 200,
+	.post_gpio_reset_off_delay_ms = 65,
+	.hid_descriptor_address = 0x0001,
+	/*
+	 * this touchscreen is tightly integrated with the panel and assumes
+	 * that the relevant power rails (other than the IO rail) have already
+	 * been turned on by the panel driver because we're a panel follower.
+	 */
+	.main_supply_name = NULL,
+};
+
+static const struct elan_i2c_hid_chip_data ilitek_ili2901_chip_data = {
+	.post_power_delay_ms = 10,
+	.post_gpio_reset_on_delay_ms = 100,
+	.hid_descriptor_address = 0x0001,
+	.main_supply_name = "vcc33",
+};
+
+static const struct elan_i2c_hid_chip_data parade_tc3408_chip_data = {
+	.post_power_delay_ms = 10,
+	.post_gpio_reset_on_delay_ms = 300,
+	.hid_descriptor_address = 0x0001,
+	.main_supply_name = "vcc33",
+};
+
+static const struct of_device_id elan_i2c_hid_of_match[] = {
+	{ .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
+	{ .compatible = "elan,ekth6a12nay", .data = &elan_ekth6a12nay_chip_data },
+	{ .compatible = "focaltech,ft8112", .data = &focaltech_ft8112_chip_data },
+	{ .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data },
+	{ .compatible = "ilitek,ili2901", .data = &ilitek_ili2901_chip_data },
+	{ .compatible = "parade,tc3408", .data = &parade_tc3408_chip_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);
+
+static struct i2c_driver elan_i2c_hid_ts_driver = {
+	.driver = {
+		.name	= "i2c_hid_of_elan",
+		.pm	= &i2c_hid_core_pm,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.of_match_table = of_match_ptr(elan_i2c_hid_of_match),
+	},
+	.probe		= i2c_hid_of_elan_probe,
+	.remove		= i2c_hid_core_remove,
+	.shutdown	= i2c_hid_core_shutdown,
+};
+module_i2c_driver(elan_i2c_hid_ts_driver);
+
+MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
+MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
new file mode 100644
index 000000000..f4dbcd1d1
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Goodix touchscreens that use the i2c-hid protocol.
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+
+#include "i2c-hid.h"
+
+struct goodix_i2c_hid_timing_data {
+	unsigned int post_gpio_reset_delay_ms;
+	unsigned int post_power_delay_ms;
+};
+
+struct i2c_hid_of_goodix {
+	struct i2chid_ops ops;
+
+	struct regulator *vdd;
+	struct regulator *vddio;
+	struct gpio_desc *reset_gpio;
+	bool no_reset_during_suspend;
+	const struct goodix_i2c_hid_timing_data *timings;
+};
+
+static int goodix_i2c_hid_power_up(struct i2chid_ops *ops)
+{
+	struct i2c_hid_of_goodix *ihid_goodix =
+		container_of(ops, struct i2c_hid_of_goodix, ops);
+	int ret;
+
+	/*
+	 * We assert reset GPIO here (instead of during power-down) to ensure
+	 * the device will have a clean state after powering up, just like the
+	 * normal scenarios will have.
+	 */
+	if (ihid_goodix->no_reset_during_suspend)
+		gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
+
+	ret = regulator_enable(ihid_goodix->vdd);
+	if (ret)
+		return ret;
+
+	ret = regulator_enable(ihid_goodix->vddio);
+	if (ret) {
+		regulator_disable(ihid_goodix->vdd);
+		return ret;
+	}
+
+	if (ihid_goodix->timings->post_power_delay_ms)
+		msleep(ihid_goodix->timings->post_power_delay_ms);
+
+	gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 0);
+	if (ihid_goodix->timings->post_gpio_reset_delay_ms)
+		msleep(ihid_goodix->timings->post_gpio_reset_delay_ms);
+
+	return 0;
+}
+
+static void goodix_i2c_hid_power_down(struct i2chid_ops *ops)
+{
+	struct i2c_hid_of_goodix *ihid_goodix =
+		container_of(ops, struct i2c_hid_of_goodix, ops);
+
+	if (!ihid_goodix->no_reset_during_suspend)
+		gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
+
+	regulator_disable(ihid_goodix->vddio);
+	regulator_disable(ihid_goodix->vdd);
+}
+
+static int i2c_hid_of_goodix_probe(struct i2c_client *client)
+{
+	struct i2c_hid_of_goodix *ihid_goodix;
+
+	ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix),
+				   GFP_KERNEL);
+	if (!ihid_goodix)
+		return -ENOMEM;
+
+	ihid_goodix->ops.power_up = goodix_i2c_hid_power_up;
+	ihid_goodix->ops.power_down = goodix_i2c_hid_power_down;
+
+	/* Start out with reset asserted */
+	ihid_goodix->reset_gpio =
+		devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ihid_goodix->reset_gpio))
+		return PTR_ERR(ihid_goodix->reset_gpio);
+
+	ihid_goodix->vdd = devm_regulator_get(&client->dev, "vdd");
+	if (IS_ERR(ihid_goodix->vdd))
+		return PTR_ERR(ihid_goodix->vdd);
+
+	ihid_goodix->vddio = devm_regulator_get(&client->dev, "mainboard-vddio");
+	if (IS_ERR(ihid_goodix->vddio))
+		return PTR_ERR(ihid_goodix->vddio);
+
+	ihid_goodix->no_reset_during_suspend =
+		of_property_read_bool(client->dev.of_node, "goodix,no-reset-during-suspend");
+
+	ihid_goodix->timings = device_get_match_data(&client->dev);
+
+	return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001, 0);
+}
+
+static const struct goodix_i2c_hid_timing_data goodix_gt7375p_timing_data = {
+	.post_power_delay_ms = 10,
+	.post_gpio_reset_delay_ms = 180,
+};
+
+static const struct of_device_id goodix_i2c_hid_of_match[] = {
+	{ .compatible = "goodix,gt7375p", .data = &goodix_gt7375p_timing_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, goodix_i2c_hid_of_match);
+
+static struct i2c_driver goodix_i2c_hid_ts_driver = {
+	.driver = {
+		.name	= "i2c_hid_of_goodix",
+		.pm	= &i2c_hid_core_pm,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.of_match_table = of_match_ptr(goodix_i2c_hid_of_match),
+	},
+	.probe		= i2c_hid_of_goodix_probe,
+	.remove		= i2c_hid_core_remove,
+	.shutdown	= i2c_hid_core_shutdown,
+};
+module_i2c_driver(goodix_i2c_hid_ts_driver);
+
+MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
+MODULE_DESCRIPTION("Goodix i2c-hid touchscreen driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/hid/i2c-hid/i2c-hid-of.c b/drivers/hid/i2c-hid/i2c-hid-of.c
new file mode 100644
index 000000000..59393d71d
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-of.c
@@ -0,0 +1,171 @@
+/*
+ * HID over I2C Open Firmware Subclass
+ *
+ * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
+ * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
+ * Copyright (c) 2012 Red Hat, Inc
+ *
+ * This code was forked out of the core code, which was partly based on
+ * "USB HID support for Linux":
+ *
+ *  Copyright (c) 1999 Andreas Gal
+ *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
+ *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
+ *  Copyright (c) 2007-2008 Oliver Neukum
+ *  Copyright (c) 2006-2010 Jiri Kosina
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive for
+ * more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/hid.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+
+#include "i2c-hid.h"
+
+struct i2c_hid_of {
+	struct i2chid_ops ops;
+
+	struct i2c_client *client;
+	struct gpio_desc *reset_gpio;
+	struct regulator_bulk_data supplies[2];
+	int post_power_delay_ms;
+	int post_reset_delay_ms;
+};
+
+static int i2c_hid_of_power_up(struct i2chid_ops *ops)
+{
+	struct i2c_hid_of *ihid_of = container_of(ops, struct i2c_hid_of, ops);
+	struct device *dev = &ihid_of->client->dev;
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ihid_of->supplies),
+				    ihid_of->supplies);
+	if (ret) {
+		dev_warn(dev, "Failed to enable supplies: %d\n", ret);
+		return ret;
+	}
+
+	if (ihid_of->post_power_delay_ms)
+		msleep(ihid_of->post_power_delay_ms);
+
+	gpiod_set_value_cansleep(ihid_of->reset_gpio, 0);
+	if (ihid_of->post_reset_delay_ms)
+		msleep(ihid_of->post_reset_delay_ms);
+
+	return 0;
+}
+
+static void i2c_hid_of_power_down(struct i2chid_ops *ops)
+{
+	struct i2c_hid_of *ihid_of = container_of(ops, struct i2c_hid_of, ops);
+
+	gpiod_set_value_cansleep(ihid_of->reset_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(ihid_of->supplies),
+			       ihid_of->supplies);
+}
+
+static int i2c_hid_of_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct i2c_hid_of *ihid_of;
+	u16 hid_descriptor_address;
+	u32 quirks = 0;
+	int ret;
+	u32 val;
+
+	ihid_of = devm_kzalloc(dev, sizeof(*ihid_of), GFP_KERNEL);
+	if (!ihid_of)
+		return -ENOMEM;
+
+	ihid_of->client = client;
+	ihid_of->ops.power_up = i2c_hid_of_power_up;
+	ihid_of->ops.power_down = i2c_hid_of_power_down;
+
+	ret = device_property_read_u32(dev, "hid-descr-addr", &val);
+	if (ret) {
+		dev_err(dev, "HID register address not provided\n");
+		return -ENODEV;
+	}
+	if (val >> 16) {
+		dev_err(dev, "Bad HID register address: 0x%08x\n", val);
+		return -EINVAL;
+	}
+	hid_descriptor_address = val;
+
+	if (!device_property_read_u32(dev, "post-power-on-delay-ms", &val))
+		ihid_of->post_power_delay_ms = val;
+
+	/*
+	 * Note this is a kernel internal device-property set by x86 platform code,
+	 * this MUST not be used in devicetree files without first adding it to
+	 * the DT bindings.
+	 */
+	if (!device_property_read_u32(dev, "post-reset-deassert-delay-ms", &val))
+		ihid_of->post_reset_delay_ms = val;
+
+	/* Start out with reset asserted */
+	ihid_of->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ihid_of->reset_gpio))
+		return PTR_ERR(ihid_of->reset_gpio);
+
+	ihid_of->supplies[0].supply = "vdd";
+	ihid_of->supplies[1].supply = "vddl";
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ihid_of->supplies),
+				      ihid_of->supplies);
+	if (ret)
+		return ret;
+
+	if (device_property_read_bool(dev, "touchscreen-inverted-x"))
+		quirks |= HID_QUIRK_X_INVERT;
+
+	if (device_property_read_bool(dev, "touchscreen-inverted-y"))
+		quirks |= HID_QUIRK_Y_INVERT;
+
+	return i2c_hid_core_probe(client, &ihid_of->ops,
+				  hid_descriptor_address, quirks);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id i2c_hid_of_match[] = {
+	{ .compatible = "hid-over-i2c" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
+#endif
+
+static const struct i2c_device_id i2c_hid_of_id_table[] = {
+	{ .name = "hid" },
+	{ .name = "hid-over-i2c" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, i2c_hid_of_id_table);
+
+static struct i2c_driver i2c_hid_of_driver = {
+	.driver = {
+		.name	= "i2c_hid_of",
+		.pm	= &i2c_hid_core_pm,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+		.of_match_table = of_match_ptr(i2c_hid_of_match),
+	},
+
+	.probe		= i2c_hid_of_probe,
+	.remove		= i2c_hid_core_remove,
+	.shutdown	= i2c_hid_core_shutdown,
+	.id_table	= i2c_hid_of_id_table,
+};
+
+module_i2c_driver(i2c_hid_of_driver);
+
+MODULE_DESCRIPTION("HID over I2C OF driver");
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/i2c-hid/i2c-hid.h b/drivers/hid/i2c-hid/i2c-hid.h
new file mode 100644
index 000000000..1724a435c
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef I2C_HID_H
+#define I2C_HID_H
+
+#include <linux/i2c.h>
+
+#ifdef CONFIG_DMI
+struct i2c_hid_desc *i2c_hid_get_dmi_i2c_hid_desc_override(uint8_t *i2c_name);
+char *i2c_hid_get_dmi_hid_report_desc_override(uint8_t *i2c_name,
+					       unsigned int *size);
+u32 i2c_hid_get_dmi_quirks(const u16 vendor, const u16 product);
+#else
+static inline struct i2c_hid_desc
+		   *i2c_hid_get_dmi_i2c_hid_desc_override(uint8_t *i2c_name)
+{ return NULL; }
+static inline char *i2c_hid_get_dmi_hid_report_desc_override(uint8_t *i2c_name,
+							     unsigned int *size)
+{ return NULL; }
+static inline u32 i2c_hid_get_dmi_quirks(const u16 vendor, const u16 product)
+{ return 0; }
+#endif
+
+/**
+ * struct i2chid_ops - Ops provided to the core.
+ *
+ * @power_up: do sequencing to power up the device.
+ * @power_down: do sequencing to power down the device.
+ * @shutdown_tail: called at the end of shutdown.
+ * @restore_sequence: hibernation restore sequence.
+ */
+struct i2chid_ops {
+	int (*power_up)(struct i2chid_ops *ops);
+	void (*power_down)(struct i2chid_ops *ops);
+	void (*shutdown_tail)(struct i2chid_ops *ops);
+	void (*restore_sequence)(struct i2chid_ops *ops);
+};
+
+int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
+		       u16 hid_descriptor_address, u32 quirks);
+void i2c_hid_core_remove(struct i2c_client *client);
+
+void i2c_hid_core_shutdown(struct i2c_client *client);
+
+extern const struct dev_pm_ops i2c_hid_core_pm;
+
+#endif