path: root/drivers/hid/i2c-hid/i2c-hid.c

/*
 * 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/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 <linux/acpi.h>
#include <linux/of.h>

#include <linux/i2c/i2c-hid.h>

/* flags */
#define I2C_HID_STARTED		(1 << 0)
#define I2C_HID_RESET_PENDING	(1 << 1)
#define I2C_HID_READ_PENDING	(1 << 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;

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) };
static const struct i2c_hid_cmd hid_no_cmd =		{ .length = 0 };

/*
 * 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) };
 */

static DEFINE_MUTEX(i2c_hid_open_mut);

/* 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 */
	char			*cmdbuf;	/* Command buffer */
	char			*argsbuf;	/* Command arguments buffer */

	unsigned long		flags;		/* device flags */

	wait_queue_head_t	wait;		/* For waiting the interrupt */

	struct i2c_hid_platform_data pdata;
};

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