i2c-hid.c 31.3 KB
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/*
 * 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>
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#include <linux/irq.h>
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#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pm.h>
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#include <linux/pm_runtime.h>
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#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>
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#include <linux/mutex.h>
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#include <linux/acpi.h>
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#include <linux/of.h>
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#include <linux/regulator/consumer.h>
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#include <linux/i2c/i2c-hid.h>

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#include "../hid-ids.h"

/* quirks to control the device */
#define I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV	BIT(0)

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/* flags */
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#define I2C_HID_STARTED		0
#define I2C_HID_RESET_PENDING	1
#define I2C_HID_READ_PENDING	2
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#define I2C_HID_PWR_ON		0x00
#define I2C_HID_PWR_SLEEP	0x01

/* debug option */
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static bool debug;
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module_param(debug, bool, 0444);
MODULE_PARM_DESC(debug, "print a lot of debug information");

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#define i2c_hid_dbg(ihid, fmt, arg...)					  \
do {									  \
	if (debug)							  \
		dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
} while (0)
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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;
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	__le32 reserved;
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} __packed;

struct i2c_hid_cmd {
	unsigned int registerIndex;
	__u8 opcode;
	unsigned int length;
	bool wait;
};

union command {
	u8 data[0];
	struct cmd {
		__le16 reg;
		__u8 reportTypeID;
		__u8 opcode;
	} __packed c;
};

#define I2C_HID_CMD(opcode_) \
	.opcode = opcode_, .length = 4, \
	.registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)

/* fetch HID descriptor */
static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
/* fetch report descriptors */
static const struct i2c_hid_cmd hid_report_descr_cmd = {
		.registerIndex = offsetof(struct i2c_hid_desc,
			wReportDescRegister),
		.opcode = 0x00,
		.length = 2 };
/* commands */
static const struct i2c_hid_cmd hid_reset_cmd =		{ I2C_HID_CMD(0x01),
							  .wait = true };
static const struct i2c_hid_cmd hid_get_report_cmd =	{ I2C_HID_CMD(0x02) };
static const struct i2c_hid_cmd hid_set_report_cmd =	{ I2C_HID_CMD(0x03) };
static const struct i2c_hid_cmd hid_set_power_cmd =	{ I2C_HID_CMD(0x08) };
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static const struct i2c_hid_cmd hid_no_cmd =		{ .length = 0 };
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/*
 * These definitions are not used here, but are defined by the spec.
 * Keeping them here for documentation purposes.
 *
 * static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
 * static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
 * static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
 * static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
 */
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static DEFINE_MUTEX(i2c_hid_open_mut);

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/* The main device structure */
struct i2c_hid {
	struct i2c_client	*client;	/* i2c client */
	struct hid_device	*hid;	/* pointer to corresponding HID dev */
	union {
		__u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
		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 */
	char			*inbuf;		/* Input buffer */
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	char			*rawbuf;	/* Raw Input buffer */
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	char			*cmdbuf;	/* Command buffer */
	char			*argsbuf;	/* Command arguments buffer */

	unsigned long		flags;		/* device flags */
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	unsigned long		quirks;		/* Various quirks */
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	wait_queue_head_t	wait;		/* For waiting the interrupt */
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	struct i2c_hid_platform_data pdata;
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	bool			irq_wake_enabled;
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	struct mutex		reset_lock;
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};

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static const struct i2c_hid_quirks {
	__u16 idVendor;
	__u16 idProduct;
	__u32 quirks;
} i2c_hid_quirks[] = {
	{ USB_VENDOR_ID_WEIDA, USB_DEVICE_ID_WEIDA_8752,
		I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV },
	{ USB_VENDOR_ID_WEIDA, USB_DEVICE_ID_WEIDA_8755,
		I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV },
	{ 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;
}

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static int __i2c_hid_command(struct i2c_client *client,
		const struct i2c_hid_cmd *command, u8 reportID,
		u8 reportType, u8 *args, int args_len,
		unsigned char *buf_recv, int data_len)
{
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	union command *cmd = (union command *)ihid->cmdbuf;
	int ret;
	struct i2c_msg msg[2];
	int msg_num = 1;

	int length = command->length;
	bool wait = command->wait;
	unsigned int registerIndex = command->registerIndex;

	/* special case for hid_descr_cmd */
	if (command == &hid_descr_cmd) {
		cmd->c.reg = ihid->wHIDDescRegister;
	} else {
		cmd->data[0] = ihid->hdesc_buffer[registerIndex];
		cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
	}

	if (length > 2) {
		cmd->c.opcode = command->opcode;
		cmd->c.reportTypeID = reportID | reportType << 4;
	}

	memcpy(cmd->data + length, args, args_len);
	length += args_len;

	i2c_hid_dbg(ihid, "%s: cmd=%*ph\n", __func__, length, cmd->data);

	msg[0].addr = client->addr;
	msg[0].flags = client->flags & I2C_M_TEN;
	msg[0].len = length;
	msg[0].buf = cmd->data;
	if (data_len > 0) {
		msg[1].addr = client->addr;
		msg[1].flags = client->flags & I2C_M_TEN;
		msg[1].flags |= I2C_M_RD;
		msg[1].len = data_len;
		msg[1].buf = buf_recv;
		msg_num = 2;
		set_bit(I2C_HID_READ_PENDING, &ihid->flags);
	}

	if (wait)
		set_bit(I2C_HID_RESET_PENDING, &ihid->flags);

	ret = i2c_transfer(client->adapter, msg, msg_num);

	if (data_len > 0)
		clear_bit(I2C_HID_READ_PENDING, &ihid->flags);

	if (ret != msg_num)
		return ret < 0 ? ret : -EIO;

	ret = 0;

	if (wait) {
		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;
		i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
	}

	return ret;
}

static int i2c_hid_command(struct i2c_client *client,
		const struct i2c_hid_cmd *command,
		unsigned char *buf_recv, int data_len)
{
	return __i2c_hid_command(client, command, 0, 0, NULL, 0,
				buf_recv, data_len);
}

static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
		u8 reportID, unsigned char *buf_recv, int data_len)
{
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	u8 args[3];
	int ret;
	int args_len = 0;
	u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);

	i2c_hid_dbg(ihid, "%s\n", __func__);

	if (reportID >= 0x0F) {
		args[args_len++] = reportID;
		reportID = 0x0F;
	}

	args[args_len++] = readRegister & 0xFF;
	args[args_len++] = readRegister >> 8;

	ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
		reportType, args, args_len, buf_recv, data_len);
	if (ret) {
		dev_err(&client->dev,
			"failed to retrieve report from device.\n");
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		return ret;
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	}

	return 0;
}

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/**
 * i2c_hid_set_or_send_report: forward an incoming report to the device
 * @client: the i2c_client of the device
 * @reportType: 0x03 for HID_FEATURE_REPORT ; 0x02 for HID_OUTPUT_REPORT
 * @reportID: the report ID
 * @buf: the actual data to transfer, without the report ID
 * @len: size of buf
 * @use_data: true: use SET_REPORT HID command, false: send plain OUTPUT report
 */
static int i2c_hid_set_or_send_report(struct i2c_client *client, u8 reportType,
		u8 reportID, unsigned char *buf, size_t data_len, bool use_data)
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{
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	u8 *args = ihid->argsbuf;
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	const struct i2c_hid_cmd *hidcmd;
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	int ret;
	u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
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	u16 outputRegister = le16_to_cpu(ihid->hdesc.wOutputRegister);
	u16 maxOutputLength = le16_to_cpu(ihid->hdesc.wMaxOutputLength);
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	u16 size;
	int args_len;
	int index = 0;

	i2c_hid_dbg(ihid, "%s\n", __func__);

	if (data_len > ihid->bufsize)
		return -EINVAL;
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	size =		2			/* size */ +
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			(reportID ? 1 : 0)	/* reportID */ +
			data_len		/* buf */;
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	args_len =	(reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
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			2			/* dataRegister */ +
			size			/* args */;

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	if (!use_data && maxOutputLength == 0)
		return -ENOSYS;

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	if (reportID >= 0x0F) {
		args[index++] = reportID;
		reportID = 0x0F;
	}

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	/*
	 * use the data register for feature reports or if the device does not
	 * support the output register
	 */
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	if (use_data) {
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		args[index++] = dataRegister & 0xFF;
		args[index++] = dataRegister >> 8;
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		hidcmd = &hid_set_report_cmd;
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	} else {
		args[index++] = outputRegister & 0xFF;
		args[index++] = outputRegister >> 8;
		hidcmd = &hid_no_cmd;
	}
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	args[index++] = size & 0xFF;
	args[index++] = size >> 8;

	if (reportID)
		args[index++] = reportID;

	memcpy(&args[index], buf, data_len);

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	ret = __i2c_hid_command(client, hidcmd, reportID,
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		reportType, args, args_len, NULL, 0);
	if (ret) {
		dev_err(&client->dev, "failed to set a report to device.\n");
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		return ret;
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	}

	return data_len;
}

static int i2c_hid_set_power(struct i2c_client *client, int power_state)
{
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	int ret;

	i2c_hid_dbg(ihid, "%s\n", __func__);

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	/*
	 * 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_command(client, &hid_set_power_cmd, NULL, 0);

		/* Device was already activated */
		if (!ret)
			goto set_pwr_exit;
	}

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	ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
		0, NULL, 0, NULL, 0);
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	if (ret)
		dev_err(&client->dev, "failed to change power setting.\n");

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set_pwr_exit:
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	return ret;
}

static int i2c_hid_hwreset(struct i2c_client *client)
{
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	int ret;

	i2c_hid_dbg(ihid, "%s\n", __func__);

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	/*
	 * This prevents sending feature reports while the device is
	 * being reset. Otherwise we may lose the reset complete
	 * interrupt.
	 */
	mutex_lock(&ihid->reset_lock);

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	ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
	if (ret)
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		goto out_unlock;
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	/*
	 * 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 and that some devices
	 * rely on this.
	 */
	usleep_range(1000, 5000);

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	i2c_hid_dbg(ihid, "resetting...\n");

	ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0);
	if (ret) {
		dev_err(&client->dev, "failed to reset device.\n");
		i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
	}

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out_unlock:
	mutex_unlock(&ihid->reset_lock);
	return ret;
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}

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static void i2c_hid_get_input(struct i2c_hid *ihid)
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{
	int ret, ret_size;
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	int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);

	if (size > ihid->bufsize)
		size = ihid->bufsize;
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	ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
	if (ret != size) {
		if (ret < 0)
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			return;
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		dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
			__func__, ret, size);
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		return;
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	}

	ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;

	if (!ret_size) {
		/* host or device initiated RESET completed */
		if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
			wake_up(&ihid->wait);
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		return;
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	}

	if (ret_size > size) {
		dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
			__func__, size, ret_size);
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		return;
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	}

	i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);

	if (test_bit(I2C_HID_STARTED, &ihid->flags))
		hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
				ret_size - 2, 1);

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	return;
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}

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;
}

static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
	size_t bufsize)
{
	struct hid_device *hid = report->device;
	struct i2c_client *client = hid->driver_data;
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	unsigned int size, ret_size;

	size = i2c_hid_get_report_length(report);
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	if (i2c_hid_get_report(client,
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			report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
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			report->id, buffer, size))
		return;
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	i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, buffer);
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	ret_size = buffer[0] | (buffer[1] << 8);

	if (ret_size != size) {
		dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
			__func__, size, ret_size);
		return;
	}

	/* hid->driver_lock is held as we are in probe function,
	 * we just need to setup the input fields, so using
	 * hid_report_raw_event is safe. */
	hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
}

/*
 * Initialize all reports
 */
static void i2c_hid_init_reports(struct hid_device *hid)
{
	struct hid_report *report;
	struct i2c_client *client = hid->driver_data;
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);

551
552
	if (!inbuf) {
		dev_err(&client->dev, "can not retrieve initial reports\n");
553
		return;
554
	}
555

556
557
558
559
560
561
	/*
	 * The device must be powered on while we fetch initial reports
	 * from it.
	 */
	pm_runtime_get_sync(&client->dev);

562
563
564
565
	list_for_each_entry(report,
		&hid->report_enum[HID_FEATURE_REPORT].report_list, list)
		i2c_hid_init_report(report, inbuf, ihid->bufsize);

566
567
	pm_runtime_put(&client->dev);

568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
	kfree(inbuf);
}

/*
 * 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;
	}
}

589
590
591
static void i2c_hid_free_buffers(struct i2c_hid *ihid)
{
	kfree(ihid->inbuf);
592
	kfree(ihid->rawbuf);
593
594
595
	kfree(ihid->argsbuf);
	kfree(ihid->cmdbuf);
	ihid->inbuf = NULL;
596
	ihid->rawbuf = NULL;
597
598
599
600
601
602
	ihid->cmdbuf = NULL;
	ihid->argsbuf = NULL;
	ihid->bufsize = 0;
}

static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
603
604
605
606
607
608
{
	/* the worst case is computed from the set_report command with a
	 * reportID > 15 and the maximum report length */
	int args_len = sizeof(__u8) + /* optional ReportID byte */
		       sizeof(__u16) + /* data register */
		       sizeof(__u16) + /* size of the report */
609
		       report_size; /* report */
610

611
	ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
612
	ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
613
614
615
	ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
	ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);

616
	if (!ihid->inbuf || !ihid->rawbuf || !ihid->argsbuf || !ihid->cmdbuf) {
617
		i2c_hid_free_buffers(ihid);
618
619
620
		return -ENOMEM;
	}

621
	ihid->bufsize = report_size;
622

623
	return 0;
624
625
626
627
628
629
630
631
}

static int i2c_hid_get_raw_report(struct hid_device *hid,
		unsigned char report_number, __u8 *buf, size_t count,
		unsigned char report_type)
{
	struct i2c_client *client = hid->driver_data;
	struct i2c_hid *ihid = i2c_get_clientdata(client);
632
	size_t ret_count, ask_count;
633
634
635
636
637
	int ret;

	if (report_type == HID_OUTPUT_REPORT)
		return -EINVAL;

638
639
	/* +2 bytes to include the size of the reply in the query buffer */
	ask_count = min(count + 2, (size_t)ihid->bufsize);
640
641
642

	ret = i2c_hid_get_report(client,
			report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
643
			report_number, ihid->rawbuf, ask_count);
644
645
646
647

	if (ret < 0)
		return ret;

648
	ret_count = ihid->rawbuf[0] | (ihid->rawbuf[1] << 8);
649

650
	if (ret_count <= 2)
651
652
653
654
655
656
		return 0;

	ret_count = min(ret_count, ask_count);

	/* The query buffer contains the size, dropping it in the reply */
	count = min(count, ret_count - 2);
657
	memcpy(buf, ihid->rawbuf + 2, count);
658
659
660
661
662

	return count;
}

static int i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
663
		size_t count, unsigned char report_type, bool use_data)
664
665
{
	struct i2c_client *client = hid->driver_data;
666
	struct i2c_hid *ihid = i2c_get_clientdata(client);
667
	int report_id = buf[0];
668
	int ret;
669
670
671
672

	if (report_type == HID_INPUT_REPORT)
		return -EINVAL;

673
674
	mutex_lock(&ihid->reset_lock);

675
676
677
678
679
	if (report_id) {
		buf++;
		count--;
	}

680
	ret = i2c_hid_set_or_send_report(client,
681
				report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
682
				report_id, buf, count, use_data);
683
684
685
686

	if (report_id && ret >= 0)
		ret++; /* add report_id to the number of transfered bytes */

687
688
	mutex_unlock(&ihid->reset_lock);

689
	return ret;
690
691
}

692
693
static int i2c_hid_output_report(struct hid_device *hid, __u8 *buf,
		size_t count)
694
{
695
696
697
	return i2c_hid_output_raw_report(hid, buf, count, HID_OUTPUT_REPORT,
			false);
}
698

699
700
701
702
static int i2c_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
			       __u8 *buf, size_t len, unsigned char rtype,
			       int reqtype)
{
703
704
	switch (reqtype) {
	case HID_REQ_GET_REPORT:
705
		return i2c_hid_get_raw_report(hid, reportnum, buf, len, rtype);
706
	case HID_REQ_SET_REPORT:
707
708
709
710
711
		if (buf[0] != reportnum)
			return -EINVAL;
		return i2c_hid_output_raw_report(hid, buf, len, rtype, true);
	default:
		return -EIO;
712
713
714
	}
}

715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
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;

	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(client);
		if (ret)
			msleep(1000);
	} while (tries-- > 0 && ret);

	if (ret)
		return ret;

	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_command(client, &hid_report_descr_cmd, 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);
	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;
775
	unsigned int bufsize = HID_MIN_BUFFER_SIZE;
776

777
778
779
	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);
780

781
	if (bufsize > ihid->bufsize) {
782
		disable_irq(client->irq);
783
784
		i2c_hid_free_buffers(ihid);

785
		ret = i2c_hid_alloc_buffers(ihid, bufsize);
786
		enable_irq(client->irq);
787

788
		if (ret)
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
			return ret;
	}

	if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
		i2c_hid_init_reports(hid);

	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);
807
	int ret = 0;
808

809
	mutex_lock(&i2c_hid_open_mut);
810
	if (!hid->open++) {
811
812
		ret = pm_runtime_get_sync(&client->dev);
		if (ret < 0) {
813
			hid->open--;
814
			goto done;
815
816
817
		}
		set_bit(I2C_HID_STARTED, &ihid->flags);
	}
818
819
done:
	mutex_unlock(&i2c_hid_open_mut);
820
	return ret < 0 ? ret : 0;
821
822
823
824
825
826
827
828
829
830
831
}

static void i2c_hid_close(struct hid_device *hid)
{
	struct i2c_client *client = hid->driver_data;
	struct i2c_hid *ihid = i2c_get_clientdata(client);

	/* protecting hid->open to make sure we don't restart
	 * data acquistion due to a resumption we no longer
	 * care about
	 */
832
	mutex_lock(&i2c_hid_open_mut);
833
834
835
836
	if (!--hid->open) {
		clear_bit(I2C_HID_STARTED, &ihid->flags);

		/* Save some power */
837
		pm_runtime_put(&client->dev);
838
	}
839
	mutex_unlock(&i2c_hid_open_mut);
840
841
842
843
844
845
846
847
848
849
850
}

static int i2c_hid_power(struct hid_device *hid, int lvl)
{
	struct i2c_client *client = hid->driver_data;
	struct i2c_hid *ihid = i2c_get_clientdata(client);

	i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);

	switch (lvl) {
	case PM_HINT_FULLON:
851
		pm_runtime_get_sync(&client->dev);
852
853
		break;
	case PM_HINT_NORMAL:
854
		pm_runtime_put(&client->dev);
855
856
		break;
	}
857
	return 0;
858
859
860
861
862
863
864
865
866
}

static 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,
	.power = i2c_hid_power,
867
868
	.output_report = i2c_hid_output_report,
	.raw_request = i2c_hid_raw_request,
869
870
};

871
static int i2c_hid_init_irq(struct i2c_client *client)
872
873
{
	struct i2c_hid *ihid = i2c_get_clientdata(client);
874
	unsigned long irqflags = 0;
875
876
	int ret;

877
	dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
878

879
880
881
	if (!irq_get_trigger_type(client->irq))
		irqflags = IRQF_TRIGGER_LOW;

882
	ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
883
				   irqflags | IRQF_ONESHOT, client->name, ihid);
884
	if (ret < 0) {
885
		dev_warn(&client->dev,
886
887
			"Could not register for %s interrupt, irq = %d,"
			" ret = %d\n",
888
			client->name, client->irq, ret);
889
890
891
892
893
894
895

		return ret;
	}

	return 0;
}

896
static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
897
898
899
900
901
902
{
	struct i2c_client *client = ihid->client;
	struct i2c_hid_desc *hdesc = &ihid->hdesc;
	unsigned int dsize;
	int ret;

903
904
905
906
	/* i2c hid fetch using a fixed descriptor size (30 bytes) */
	i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
	ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
				sizeof(struct i2c_hid_desc));
907
	if (ret) {
908
		dev_err(&client->dev, "hid_descr_cmd failed\n");
909
910
911
		return -ENODEV;
	}

912
913
914
	/* Validate the length of HID descriptor, the 4 first bytes:
	 * bytes 0-1 -> length
	 * bytes 2-3 -> bcdVersion (has to be 1.00) */
915
916
917
	/* check bcdVersion == 1.0 */
	if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
		dev_err(&client->dev,
918
			"unexpected HID descriptor bcdVersion (0x%04hx)\n",
919
920
921
922
			le16_to_cpu(hdesc->bcdVersion));
		return -ENODEV;
	}

923
924
925
926
927
	/* 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(&client->dev, "weird size of HID descriptor (%u)\n",
			dsize);
928
929
930
931
932
933
		return -ENODEV;
	}
	i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
	return 0;
}

934
935
936
937
938
939
940
941
#ifdef CONFIG_ACPI
static int i2c_hid_acpi_pdata(struct i2c_client *client,
		struct i2c_hid_platform_data *pdata)
{
	static u8 i2c_hid_guid[] = {
		0xF7, 0xF6, 0xDF, 0x3C, 0x67, 0x42, 0x55, 0x45,
		0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE,
	};
942
	union acpi_object *obj;
943
944
945
946
947
948
949
	struct acpi_device *adev;
	acpi_handle handle;

	handle = ACPI_HANDLE(&client->dev);
	if (!handle || acpi_bus_get_device(handle, &adev))
		return -ENODEV;

950
951
952
	obj = acpi_evaluate_dsm_typed(handle, i2c_hid_guid, 1, 1, NULL,
				      ACPI_TYPE_INTEGER);
	if (!obj) {
953
954
955
956
		dev_err(&client->dev, "device _DSM execution failed\n");
		return -ENODEV;
	}

957
958
	pdata->hid_descriptor_address = obj->integer.value;
	ACPI_FREE(obj);
959

960
	return 0;
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
}

static const struct acpi_device_id i2c_hid_acpi_match[] = {
	{"ACPI0C50", 0 },
	{"PNP0C50", 0 },
	{ },
};
MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
#else
static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
		struct i2c_hid_platform_data *pdata)
{
	return -ENODEV;
}
#endif

977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
#ifdef CONFIG_OF
static int i2c_hid_of_probe(struct i2c_client *client,
		struct i2c_hid_platform_data *pdata)
{
	struct device *dev = &client->dev;
	u32 val;
	int ret;

	ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
	if (ret) {
		dev_err(&client->dev, "HID register address not provided\n");
		return -ENODEV;
	}
	if (val >> 16) {
		dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
			val);
		return -EINVAL;
	}
	pdata->hid_descriptor_address = val;

	return 0;
}

static const struct of_device_id i2c_hid_of_match[] = {
	{ .compatible = "hid-over-i2c" },
	{},
};
MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
#else
static inline int i2c_hid_of_probe(struct i2c_client *client,
		struct i2c_hid_platform_data *pdata)
{
	return -ENODEV;
}
#endif

1013
1014
static int i2c_hid_probe(struct i2c_client *client,
			 const struct i2c_device_id *dev_id)
1015
1016
1017
1018
1019
1020
1021
1022
1023
{
	int ret;
	struct i2c_hid *ihid;
	struct hid_device *hid;
	__u16 hidRegister;
	struct i2c_hid_platform_data *platform_data = client->dev.platform_data;

	dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);

1024
1025
1026
1027
1028
1029
	if (!client->irq) {
		dev_err(&client->dev,
			"HID over i2c has not been provided an Int IRQ\n");
		return -EINVAL;
	}

1030
1031
1032
1033
1034
1035
1036
	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;
	}

1037
1038
1039
1040
	ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
	if (!ihid)
		return -ENOMEM;

1041
1042
1043
1044
1045
	if (client->dev.of_node) {
		ret = i2c_hid_of_probe(client, &ihid->pdata);
		if (ret)
			goto err;
	} else if (!platform_data) {
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
		ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
		if (ret) {
			dev_err(&client->dev,
				"HID register address not provided\n");
			goto err;
		}
	} else {
		ihid->pdata = *platform_data;
	}

1056
1057
1058
1059
	i2c_set_clientdata(client, ihid);

	ihid->client = client;

1060
	hidRegister = ihid->pdata.hid_descriptor_address;
1061
1062
1063
	ihid->wHIDDescRegister = cpu_to_le16(hidRegister);

	init_waitqueue_head(&ihid->wait);
1064
	mutex_init(&ihid->reset_lock);
1065
1066
1067
1068

	/* 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. */
1069
1070
1071
	ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
	if (ret < 0)
		goto err;
1072

1073
1074
1075
	pm_runtime_get_noresume(&client->dev);
	pm_runtime_set_active(&client->dev);
	pm_runtime_enable(&client->dev);
1076
	device_enable_async_suspend(&client->dev);
1077

1078
1079
	ret = i2c_hid_fetch_hid_descriptor(ihid);
	if (ret < 0)
1080
		goto err_pm;
1081
1082
1083

	ret = i2c_hid_init_irq(client);
	if (ret < 0)
1084
		goto err_pm;
1085
1086
1087
1088

	hid = hid_allocate_device();
	if (IS_ERR(hid)) {
		ret = PTR_ERR(hid);
1089
		goto err_irq;
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
	}

	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);

1102
	snprintf(hid->name, sizeof(hid->name), "%s %04hX:%04hX",
1103
		 client->name, hid->vendor, hid->product);
1104
	strlcpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
1105

1106
1107
	ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);

1108
1109
1110
1111
1112
1113
1114
	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;
	}

1115
	pm_runtime_put(&client->dev);
1116
1117
1118
1119
1120
	return 0;

err_mem_free:
	hid_destroy_device(hid);

1121
err_irq:
1122
	free_irq(client->irq, ihid);
1123

1124
1125
1126
1127
err_pm:
	pm_runtime_put_noidle(&client->dev);
	pm_runtime_disable(&client->dev);

1128
err:
1129
	i2c_hid_free_buffers(ihid);
1130
1131
1132
1133
	kfree(ihid);
	return ret;
}

1134
static int i2c_hid_remove(struct i2c_client *client)
1135
1136
1137
1138
{
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	struct hid_device *hid;

1139
1140
1141
1142
1143
	pm_runtime_get_sync(&client->dev);
	pm_runtime_disable(&client->dev);
	pm_runtime_set_suspended(&client->dev);
	pm_runtime_put_noidle(&client->dev);

1144
1145
1146
	hid = ihid->hid;
	hid_destroy_device(hid);

1147
	free_irq(client->irq, ihid);
1148

1149
1150
1151
	if (ihid->bufsize)
		i2c_hid_free_buffers(ihid);

1152
1153
1154
1155
1156
	kfree(ihid);

	return 0;
}

1157
1158
1159
1160
1161
1162
1163
1164
static void i2c_hid_shutdown(struct i2c_client *client)
{
	struct i2c_hid *ihid = i2c_get_clientdata(client);

	i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
	free_irq(client->irq, ihid);
}

1165
1166
1167
1168
#ifdef CONFIG_PM_SLEEP
static int i2c_hid_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
1169
1170
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	struct hid_device *hid = ihid->hid;
1171
	int ret;
1172
	int wake_status;
1173

1174
1175
1176
1177
1178
1179
1180
1181
1182
	if (hid->driver && hid->driver->suspend) {
		/*
		 * Wake up the device so that IO issues in
		 * HID driver's suspend code can succeed.
		 */
		ret = pm_runtime_resume(dev);
		if (ret < 0)
			return ret;

1183
		ret = hid->driver->suspend(hid, PMSG_SUSPEND);
1184
1185
1186
1187
1188
1189
1190
1191
		if (ret < 0)
			return ret;
	}

	if (!pm_runtime_suspended(dev)) {
		/* Save some power */
		i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);

1192
		disable_irq(client->irq);
1193
	}
1194

1195
	if (device_may_wakeup(&client->dev)) {
1196
		wake_status = enable_irq_wake(client->irq);
1197
1198
1199
1200
1201
1202
		if (!wake_status)
			ihid->irq_wake_enabled = true;
		else
			hid_warn(hid, "Failed to enable irq wake: %d\n",
				wake_status);
	}
1203

1204
	return 0;
1205
1206
1207
1208
1209
1210
}

static int i2c_hid_resume(struct device *dev)
{
	int ret;
	struct i2c_client *client = to_i2c_client(dev);
1211
1212
	struct i2c_hid *ihid = i2c_get_clientdata(client);
	struct hid_device *hid = ihid->hid;
1213
	int wake_status;
1214

1215
	if (device_may_wakeup(&client->dev) && ihid->irq_wake_enabled) {
1216
		wake_status = disable_irq_wake(client->irq);
1217
1218
1219
1220
1221
1222
		if (!wake_status)
			ihid->irq_wake_enabled = false;
		else
			hid_warn(hid, "Failed to disable irq wake: %d\n",
				wake_status);
	}
1223

1224
1225
1226
1227
1228
	/* We'll resume to full power */
	pm_runtime_disable(dev);
	pm_runtime_set_active(dev);
	pm_runtime_enable(dev);

1229
	enable_irq(client->irq);
1230
1231
1232
1233
	ret = i2c_hid_hwreset(client);
	if (ret)
		return ret;

1234
1235
1236
1237
1238
	if (hid->driver && hid->driver->reset_resume) {
		ret = hid->driver->reset_resume(hid);
		return ret;
	}

1239
1240
1241
1242
	return 0;
}
#endif

1243
#ifdef CONFIG_PM
1244
1245
1246
1247
1248
static int i2c_hid_runtime_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);

	i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1249
	disable_irq(client->irq);
1250
1251
1252
1253
1254
1255
1256
	return 0;
}

static int i2c_hid_runtime_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);

1257
	enable_irq(client->irq);
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
	i2c_hid_set_power(client, I2C_HID_PWR_ON);
	return 0;
}
#endif

static const struct dev_pm_ops i2c_hid_pm = {
	SET_SYSTEM_SLEEP_PM_OPS(i2c_hid_suspend, i2c_hid_resume)
	SET_RUNTIME_PM_OPS(i2c_hid_runtime_suspend, i2c_hid_runtime_resume,
			   NULL)
};
1268
1269

static const struct i2c_device_id i2c_hid_id_table[] = {
1270
	{ "hid", 0 },
1271
	{ "hid-over-i2c", 0 },
1272
1273
1274
1275
1276
1277
1278
1279
1280
	{ },
};
MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);


static struct i2c_driver i2c_hid_driver = {
	.driver = {
		.name	= "i2c_hid",
		.pm	= &i2c_hid_pm,
1281
		.acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
1282
		.of_match_table = of_match_ptr(i2c_hid_of_match),
1283
1284
1285
	},

	.probe		= i2c_hid_probe,
1286
	.remove		= i2c_hid_remove,
1287
	.shutdown	= i2c_hid_shutdown,
1288
1289
1290
1291
1292
1293
1294
1295
	.id_table	= i2c_hid_id_table,
};

module_i2c_driver(i2c_hid_driver);

MODULE_DESCRIPTION("HID over I2C core driver");
MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
MODULE_LICENSE("GPL");