Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1178 insertions, 0 deletions

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..969f8eb08
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -0,0 +1,1178 @@
+/*
+ * 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/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 <asm/unaligned.h>
+
+#include "../hid-ids.h"
+#include "i2c-hid.h"
+
+/* quirks to control the device */
+#define I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV	BIT(0)
+#define I2C_HID_QUIRK_NO_IRQ_AFTER_RESET	BIT(1)
+#define I2C_HID_QUIRK_BOGUS_IRQ			BIT(4)
+#define I2C_HID_QUIRK_RESET_ON_RESUME		BIT(5)
+#define I2C_HID_QUIRK_BAD_INPUT_SIZE		BIT(6)
+#define I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET	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_READ_PENDING	2
+
+#define I2C_HID_PWR_ON		0x00
+#define I2C_HID_PWR_SLEEP	0x01
+
+/* debug option */
+static bool debug;
+module_param(debug, bool, 0444);
+MODULE_PARM_DESC(debug, "print a lot of debug information");
+
+#define i2c_hid_dbg(ihid, fmt, arg...)					  \
+do {									  \
+	if (debug)							  \
+		dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
+} while (0)
+
+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 */
+
+	bool			irq_wake_enabled;
+	struct mutex		reset_lock;
+
+	struct i2chid_ops	*ops;
+};
+
+static const struct i2c_hid_quirks {
+	__u16 idVendor;
+	__u16 idProduct;
+	__u32 quirks;
+} i2c_hid_quirks[] = {
+	{ USB_VENDOR_ID_WEIDA, HID_ANY_ID,
+		I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV },
+	{ 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 },
+	/*
+	 * 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 },
+	{ 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_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++;
+
+		set_bit(I2C_HID_READ_PENDING, &ihid->flags);
+	}
+
+	ret = i2c_transfer(client->adapter, msgs, n);
+
+	if (recv_len)
+		clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
+
+	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)
+{
+	*(__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__);
+
+	/* 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 .
+	 */
+	error = i2c_hid_xfer(ihid, ihid->cmdbuf, length,
+			     ihid->rawbuf, recv_len + sizeof(__le16));
+	if (error) {
+		dev_err(&ihid->client->dev,
+			"failed to set a report to 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;
+
+	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;
+
+	/* 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 devices require to send a command to wakeup before power on.
+	 * The call will get a return value (EREMOTEIO) but device will be
+	 * triggered and activated. After that, it goes like a normal device.
+	 */
+	if (power_state == I2C_HID_PWR_ON &&
+	    ihid->quirks & I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV) {
+		ret = i2c_hid_set_power_command(ihid, I2C_HID_PWR_ON);
+
+		/* Device was already activated */
+		if (!ret)
+			goto set_pwr_exit;
+	}
+
+	ret = i2c_hid_set_power_command(ihid, power_state);
+	if (ret)
+		dev_err(&ihid->client->dev,
+			"failed to change power setting.\n");
+
+set_pwr_exit:
+
+	/*
+	 * 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_execute_reset(struct i2c_hid *ihid)
+{
+	size_t length = 0;
+	int ret;
+
+	i2c_hid_dbg(ihid, "resetting...\n");
+
+	/* 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.\n");
+		goto out;
+	}
+
+	if (ihid->quirks & I2C_HID_QUIRK_NO_IRQ_AFTER_RESET) {
+		msleep(100);
+		goto out;
+	}
+
+	i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
+	if (!wait_event_timeout(ihid->wait,
+				!test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
+				msecs_to_jiffies(5000))) {
+		ret = -ENODATA;
+		goto out;
+	}
+	i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
+
+out:
+	clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
+	return ret;
+}
+
+static int i2c_hid_hwreset(struct i2c_hid *ihid)
+{
+	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.
+	 */
+	mutex_lock(&ihid->reset_lock);
+
+	ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
+	if (ret)
+		goto out_unlock;
+
+	ret = i2c_hid_execute_reset(ihid);
+	if (ret) {
+		dev_err(&ihid->client->dev,
+			"failed to reset device: %d\n", ret);
+		i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
+		goto out_unlock;
+	}
+
+	/* 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);
+
+out_unlock:
+	mutex_unlock(&ihid->reset_lock);
+	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_input_report(ihid->hid, HID_INPUT_REPORT,
+				ihid->inbuf + 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;
+
+	if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
+		return IRQ_HANDLED;
+
+	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;
+	unsigned int rsize;
+	char *rdesc;
+	int ret;
+	int tries = 3;
+	char *use_override;
+
+	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;
+	}
+
+	do {
+		ret = i2c_hid_hwreset(ihid);
+		if (ret)
+			msleep(1000);
+	} while (tries-- > 0 && ret);
+
+	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) {
+			dbg_hid("couldn't allocate rdesc memory\n");
+			return -ENOMEM;
+		}
+
+		i2c_hid_dbg(ihid, "asking HID report descriptor\n");
+
+		ret = i2c_hid_read_register(ihid,
+					    ihid->hdesc.wReportDescRegister,
+					    rdesc, rsize);
+		if (ret) {
+			hid_err(hid, "reading report descriptor failed\n");
+			kfree(rdesc);
+			return -EIO;
+		}
+	}
+
+	i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
+
+	ret = hid_parse_report(hid, rdesc, rsize);
+	if (!use_override)
+		kfree(rdesc);
+
+	if (ret) {
+		dbg_hid("parsing report descriptor failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+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);
+}
+
+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,
+};
+EXPORT_SYMBOL_GPL(i2c_hid_ll_driver);
+
+static int i2c_hid_init_irq(struct i2c_client *client)
+{
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	unsigned long irqflags = 0;
+	int ret;
+
+	dev_dbg(&client->dev, "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, 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);
+}
+
+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;
+
+	ihid->ops = ops;
+
+	ret = i2c_hid_core_power_up(ihid);
+	if (ret)
+		return ret;
+
+	i2c_set_clientdata(client, ihid);
+
+	ihid->client = client;
+
+	ihid->wHIDDescRegister = cpu_to_le16(hid_descriptor_address);
+
+	init_waitqueue_head(&ihid->wait);
+	mutex_init(&ihid->reset_lock);
+
+	/* 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)
+		goto err_powered;
+
+	device_enable_async_suspend(&client->dev);
+
+	/* Make sure there is something at this address */
+	ret = i2c_smbus_read_byte(client);
+	if (ret < 0) {
+		dev_dbg(&client->dev, "nothing at this address: %d\n", ret);
+		ret = -ENXIO;
+		goto err_powered;
+	}
+
+	ret = i2c_hid_fetch_hid_descriptor(ihid);
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"Failed to fetch the HID Descriptor\n");
+		goto err_powered;
+	}
+
+	ret = i2c_hid_init_irq(client);
+	if (ret < 0)
+		goto err_powered;
+
+	hid = hid_allocate_device();
+	if (IS_ERR(hid)) {
+		ret = PTR_ERR(hid);
+		goto err_irq;
+	}
+
+	ihid->hid = hid;
+
+	hid->driver_data = client;
+	hid->ll_driver = &i2c_hid_ll_driver;
+	hid->dev.parent = &client->dev;
+	hid->bus = BUS_I2C;
+	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 = quirks;
+	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);
+
+	ret = hid_add_device(hid);
+	if (ret) {
+		if (ret != -ENODEV)
+			hid_err(client, "can't add hid device: %d\n", ret);
+		goto err_mem_free;
+	}
+
+	return 0;
+
+err_mem_free:
+	hid_destroy_device(hid);
+
+err_irq:
+	free_irq(client->irq, ihid);
+
+err_powered:
+	i2c_hid_core_power_down(ihid);
+	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;
+
+	hid = ihid->hid;
+	hid_destroy_device(hid);
+
+	free_irq(client->irq, ihid);
+
+	if (ihid->bufsize)
+		i2c_hid_free_buffers(ihid);
+
+	i2c_hid_core_power_down(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);
+
+#ifdef CONFIG_PM_SLEEP
+static int i2c_hid_core_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	struct hid_device *hid = ihid->hid;
+	int ret;
+	int wake_status;
+
+	ret = hid_driver_suspend(hid, PMSG_SUSPEND);
+	if (ret < 0)
+		return ret;
+
+	/* Save some power */
+	i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
+
+	disable_irq(client->irq);
+
+	if (device_may_wakeup(&client->dev)) {
+		wake_status = enable_irq_wake(client->irq);
+		if (!wake_status)
+			ihid->irq_wake_enabled = true;
+		else
+			hid_warn(hid, "Failed to enable irq wake: %d\n",
+				wake_status);
+	} else {
+		i2c_hid_core_power_down(ihid);
+	}
+
+	return 0;
+}
+
+static int i2c_hid_core_resume(struct device *dev)
+{
+	int ret;
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_hid *ihid = i2c_get_clientdata(client);
+	struct hid_device *hid = ihid->hid;
+	int wake_status;
+
+	if (!device_may_wakeup(&client->dev)) {
+		i2c_hid_core_power_up(ihid);
+	} else if (ihid->irq_wake_enabled) {
+		wake_status = disable_irq_wake(client->irq);
+		if (!wake_status)
+			ihid->irq_wake_enabled = false;
+		else
+			hid_warn(hid, "Failed to disable irq wake: %d\n",
+				wake_status);
+	}
+
+	enable_irq(client->irq);
+
+	/* 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)
+		ret = i2c_hid_hwreset(ihid);
+	else
+		ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
+
+	if (ret)
+		return ret;
+
+	return hid_driver_reset_resume(hid);
+}
+#endif
+
+const struct dev_pm_ops i2c_hid_core_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(i2c_hid_core_suspend, i2c_hid_core_resume)
+};
+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");