linux/drivers/input/input.c

/*
 * The input core
 *
 * Copyright (c) 1999-2002 Vojtech Pavlik
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_BASENAME ": " fmt

#include <linux/init.h>
#include <linux/types.h>
#include <linux/idr.h>
#include <linux/input/mt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/major.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include "input-compat.h"

MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
MODULE_DESCRIPTION("Input core");
MODULE_LICENSE("GPL");

#define INPUT_MAX_CHAR_DEVICES		1024
#define INPUT_FIRST_DYNAMIC_DEV		256
static DEFINE_IDA(input_ida);

static LIST_HEAD(input_dev_list);
static LIST_HEAD(input_handler_list);

/*
 * input_mutex protects access to both input_dev_list and input_handler_list.
 * This also causes input_[un]register_device and input_[un]register_handler
 * be mutually exclusive which simplifies locking in drivers implementing
 * input handlers.
 */
static DEFINE_MUTEX(input_mutex);

static const struct input_value input_value_sync = { EV_SYN, SYN_REPORT, 1 };

static inline int is_event_supported(unsigned int code,
				     unsigned long *bm, unsigned int max)
{
	return code <= max && test_bit(code, bm);
}

static int input_defuzz_abs_event(int value, int old_val, int fuzz)
{
	if (fuzz) {
		if (value > old_val - fuzz / 2 && value < old_val + fuzz / 2)
			return old_val;

		if (value > old_val - fuzz && value < old_val + fuzz)
			return (old_val * 3 + value) / 4;

		if (value > old_val - fuzz * 2 && value < old_val + fuzz * 2)
			return (old_val + value) / 2;
	}

	return value;
}

static void input_start_autorepeat(struct input_dev *dev, int code)
{
	if (test_bit(EV_REP, dev->evbit) &&
	    dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] &&
	    dev->timer.data) {
		dev->repeat_key = code;
		mod_timer(&dev->timer,
			  jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
	}
}

static void input_stop_autorepeat(struct input_dev *dev)
{
	del_timer(&dev->timer);
}

/*
 * Pass event first through all filters and then, if event has not been
 * filtered out, through all open handles. This function is called with
 * dev->event_lock held and interrupts disabled.
 */
static unsigned int input_to_handler(struct input_handle *handle,
			struct input_value *vals, unsigned int count)
{
	struct input_handler *handler = handle->handler;
	struct input_value *end = vals;
	struct input_value *v;

	if (handler->filter) {
		for (v = vals; v != vals + count; v++) {
			if (handler->filter(handle, v->type, v->code, v->value))
				continue;
			if (end != v)
				*end = *v;
			end++;
		}
		count = end - vals;
	}

	if (!count)
		return 0;

	if (handler->events)
		handler->events(handle, vals, count);
	else if (handler->event)
		for (v = vals; v != vals + count; v++)
			handler->event(handle, v->type, v->code, v->value);

	return count;
}

/*
 * Pass values first through all filters and then, if event has not been
 * filtered out, through all open handles. This function is called with
 * dev->event_lock held and interrupts disabled.
 */
static void input_pass_values(struct input_dev *dev,
			      struct input_value *vals, unsigned int count)
{
	struct input_handle *handle;
	struct input_value *v;

	if (!count)
		return;

	rcu_read_lock();

	handle = rcu_dereference(dev->grab);
	if (handle) {
		count = input_to_handler(handle, vals, count);
	} else {
		list_for_each_entry_rcu(handle, &dev->h_list, d_node)
			if (handle->open) {
				count = input_to_handler(handle, vals, count);
				if (!count)
					break;
			}
	}

	rcu_read_unlock();

	/* trigger auto repeat for key events */
	if (test_bit(EV_REP, dev->evbit) && test_bit(EV_KEY, dev->evbit)) {
		for (v = vals; v != vals + count; v++) {
			if (v->type == EV_KEY && v->value != 2) {
				if (v->value)
					input_start_autorepeat(dev, v->code);
				else
					input_stop_autorepeat(dev);
			}
		}
	}
}

static void input_pass_event(struct input_dev *dev,
			     unsigned int type, unsigned int code, int value)
{
	struct input_value vals[] = { { type, code, value } };

	input_pass_values(dev, vals, ARRAY_SIZE(vals));
}

/*
 * Generate software autorepeat event. Note that we take
 * dev->event_lock here to avoid racing with input_event
 * which may cause keys get "stuck".
 */
static void input_repeat_key(unsigned long data)
{
	struct input_dev *dev = (void *) data;
	unsigned long flags;

	spin_lock_irqsave(&dev->event_lock, flags);

	if (test_bit(dev->repeat_key, dev->key) &&
	    is_event_supported(dev->repeat_key, dev->keybit, KEY_MAX)) {
		struct input_value vals[] =  {
			{ EV_KEY, dev->repeat_key, 2 },
			input_value_sync
		};

		input_pass_values(dev, vals, ARRAY_SIZE(vals));

		if (dev->rep[REP_PERIOD])
			mod_timer(&dev->timer, jiffies +
					msecs_to_jiffies(dev->rep[REP_PERIOD]));
	}

	spin_unlock_irqrestore(&dev->event_lock, flags);
}

#define INPUT_IGNORE_EVENT	0
#define INPUT_PASS_TO_HANDLERS	1
#define INPUT_PASS_TO_DEVICE	2
#define INPUT_SLOT		4
#define INPUT_FLUSH		8
#define INPUT_PASS_TO_ALL	(INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)

static int input_handle_abs_event(struct input_dev *dev,
				  unsigned int code, int *pval)
{
	struct input_mt *mt = dev->mt;
	bool is_mt_event;
	int *pold;

	if (code == ABS_MT_SLOT) {
		/*
		 * "Stage" the event; we'll flush it later, when we
		 * get actual touch data.
		 */
		if (mt && *pval >= 0 && *pval < mt->num_slots)
			mt->slot = *pval;

		return INPUT_IGNORE_EVENT;
	}

	is_mt_event = input_is_mt_value(code);

	if (!is_mt_event) {
		pold = &dev->absinfo[code].value;
	} else if (mt) {
		pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST];
	} else {
		/*
		 * Bypass filtering for multi-touch events when
		 * not employing slots.
		 */
		pold = NULL;
	}

	if (pold) {
		*pval = input_defuzz_abs_event(*pval, *pold,
						dev->absinfo[code].fuzz);
		if (*pold == *pval)
			return INPUT_IGNORE_EVENT;

		*pold = *pval;
	}

	/* Flush pending "slot" event */
	if (is_mt_event && mt && mt->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
		input_abs_set_val(dev, ABS_MT_SLOT, mt->slot);
		return INPUT_PASS_TO_HANDLERS | INPUT_SLOT;
	}

	return INPUT_PASS_TO_HANDLERS;
}

static int input_get_disposition(struct input_dev *dev,
			  unsigned int type, unsigned int code, int *pval)
{
	int disposition = INPUT_IGNORE_EVENT;
	int value = *pval;

	switch (type) {

	case EV_SYN:
		switch (code) {
		case SYN_CONFIG:
			disposition = INPUT_PASS_TO_ALL;
			break;

		case SYN_REPORT:
			disposition = INPUT_PASS_TO_HANDLERS | INPUT_FLUSH;
			break;
		case SYN_MT_REPORT:
			disposition = INPUT_PASS_TO_HANDLERS;
			break;
		}
		break;

	case EV_KEY:
		if (is_event_supported(code, dev->keybit, KEY_MAX)) {

			/* auto-repeat bypasses state updates */
			if (value == 2) {
				disposition = INPUT_PASS_TO_HANDLERS;
				break;
			}

			if (!!test_bit(code, dev->key) != !!value) {

				__change_bit(code, dev->key);
				disposition = INPUT_PASS_TO_HANDLERS;
			}
		}
		break;

	case EV_SW:
		if (is_event_supported(code, dev->swbit, SW_MAX) &&
		    !!test_bit(code, dev->sw) != !!value) {

			__change_bit(code, dev->sw);
			disposition = INPUT_PASS_TO_HANDLERS;
		}
		break;

	case EV_ABS:
		if (is_event_supported(code, dev->absbit, ABS_MAX))
			disposition = input_handle_abs_event(dev, code, &value);

		break;

	case EV_REL:
		if (is_event_supported(code, dev->relbit, REL_MAX) && value)
			disposition = INPUT_PASS_TO_HANDLERS;

		break;

	case EV_MSC:
		if (is_event_supported(code, dev->mscbit, MSC_MAX))
			disposition = INPUT_PASS_TO_ALL;

		break;

	case EV_LED:
		if (is_event_supported(code, dev->ledbit, LED_MAX) &&
		    !!test_bit(code, dev->led) != !!value) {

			__change_bit(code, dev->led);
			disposition = INPUT_PASS_TO_ALL;
		}
		break;

	case EV_SND:
		if (is_event_supported(code, dev->sndbit, SND_MAX)) {

			if (!!test_bit(code, dev->snd) != !!value)
				__change_bit(code, dev->snd);
			disposition = INPUT_PASS_TO_ALL;
		}
		break;

	case EV_REP:
		if (code <= REP_MAX && value >= 0 && dev->rep[code] != value) {
			dev->rep[code] = value;
			disposition = INPUT_PASS_TO_ALL;
		}
		break;

	case EV_FF:
		if (value >= 0)
			disposition = INPUT_PASS_TO_ALL;
		break;

	case EV_PWR:
		disposition = INPUT_PASS_TO_ALL;
		break;
	}

	*pval = value;
	return disposition;
}

static void input_handle_event(struct input_dev *dev,
			       unsigned int type, unsigned int code, int value)
{
	int disposition = input_get_disposition(dev, type, code, &value);

	if (disposition != INPUT_IGNORE_EVENT && type != EV_SYN)
		add_input_randomness(type, code, value);

	if ((disposition & INPUT_PASS_TO_DEVICE) && dev->event)
		dev->event(dev, type, code, value);

	if (!dev->vals)
		return;

	if (disposition & INPUT_PASS_TO_HANDLERS) {
		struct input_value *v;

		if (disposition & INPUT_SLOT) {
			v = &dev->vals[dev->num_vals++];
			v->type = EV_ABS;
			v->code = ABS_MT_SLOT;
			v->value = dev->mt->slot;
		}

		v = &dev->vals[dev->num_vals++];
		v->type = type;
		v->code = code;
		v->value = value;
	}

	if (disposition & INPUT_FLUSH) {
		if (dev->num_vals >= 2)
			input_pass_values(dev, dev->vals, dev->num_vals);
		dev->num_vals = 0;
	} else if (dev->num_vals >= dev->max_vals - 2) {
		dev->vals[dev->num_vals++] = input_value_sync;
		input_pass_values(dev, dev->vals, dev->num_vals);
		dev->num_vals = 0;
	}

}

/**
 * input_event() - report new input event
 * @dev: device that generated the event
 * @type: type of the event
 * @code: event code
 * @value: value of the event
 *
 * This function should be used by drivers implementing various input
 * devices to report input events. See also input_inject_event().
 *
 * NOTE: input_event() may be safely used right after input device was
 * allocated with input_allocate_device(), even before it is registered
 * with input_register_device(), but the event will not reach any of the
 * input handlers. Such early invocation of input_event() may be used
 * to 'seed' initial state of a switch or initial position of absolute
 * axis, etc.
 */
void input_event(struct input_dev *dev,
		 unsigned int type, unsigned int code, int value)
{
	unsigned long flags;

	if (is_event_supported(type, dev->evbit, EV_MAX)) {

		spin_lock_irqsave(&dev->event_lock, flags);
		input_handle_event(dev, type, code, value);
		spin_unlock_irqrestore(&dev->event_lock, flags);
	}
}
EXPORT_SYMBOL(input_event);

/**
 * input_inject_event() - send input event from input handler
 * @handle: input handle to send event through
 * @type: type of the event
 * @code: event code
 * @value: value of the event
 *
 * Similar to input_event() but will ignore event if device is
 * "grabbed" and handle injecting event is not the one that owns
 * the device.
 */
void input_inject_event(struct input_handle *handle,
			unsigned int type, unsigned int code, int value)
{
	struct input_dev *dev = handle->dev;
	struct input_handle *grab;
	unsigned long flags;

	if (is_event_supported(type, dev->evbit, EV_MAX)) {
		spin_lock_irqsave(&dev->event_lock, flags);

		rcu_read_lock();
		grab = rcu_dereference(dev->grab);
		if (!grab || grab == handle)
			input_handle_event(dev, type, code, value);
		rcu_read_unlock();

		spin_unlock_irqrestore(&dev->event_lock, flags);
	}
}
EXPORT_SYMBOL(input_inject_event);

/**
 * input_alloc_absinfo - allocates array of input_absinfo structs
 * @dev: the input device emitting absolute events
 *
 * If the absinfo struct the caller asked for is already allocated, this
 * functions will not do anything.
 */
void input_alloc_absinfo(struct input_dev *dev)
{
	if (!dev->absinfo)
		dev->absinfo = kcalloc(ABS_CNT, sizeof(struct input_absinfo),
					GFP_KERNEL);

	WARN(!dev->absinfo, "%s(): kcalloc() failed?\n", __func__);
}
EXPORT_SYMBOL(input_alloc_absinfo);

void input_set_abs_params(struct input_dev *dev, unsigned int axis,
			  int min, int max, int fuzz, int flat)
{
	struct input_absinfo *absinfo;

	input_alloc_absinfo(dev);
	if (!dev->absinfo)
		return;

	absinfo = &dev->absinfo[axis];
	absinfo->minimum = min;
	absinfo->maximum = max;
	absinfo->fuzz = fuzz;
	absinfo->flat = flat;

	__set_bit(EV_ABS, dev->evbit);
	__set_bit(axis, dev->absbit);
}
EXPORT_SYMBOL(input_set_abs_params);


/**
 * input_grab_device - grabs device for exclusive use
 * @handle: input handle that wants to own the device
 *
 * When a device is grabbed by an input handle all events generated by
 * the device are delivered only to this handle. Also events injected
 * by other input handles are ignored while device is grabbed.
 */
int input_grab_device(struct input_handle *handle)
{
	struct input_dev *dev = handle->dev;
	int retval;

	retval = mutex_lock_interruptible(&dev->mutex);
	if (retval)
		return retval;

	if (dev->grab) {
		retval = -EBUSY;
		goto out;
	}

	rcu_assign_pointer(dev->grab, handle);

 out:
	mutex_unlock(&dev->mutex);
	return retval;
}
EXPORT_SYMBOL(input_grab_device);

static void __input_release_device(struct input_handle *handle)
{
	struct input_dev *dev = handle->dev;
	struct input_handle *grabber;

	grabber = rcu_dereference_protected(dev->grab,
					    lockdep_is_held(&dev->mutex));
	if (grabber == handle) {
		rcu_assign_pointer(dev->grab, NULL);
		/* Make sure input_pass_event() notices that grab is gone */
		synchronize_rcu();

		list_for_each_entry(handle, &dev->h_list, d_node)
			if (handle->open && handle->handler->start)
				handle->handler->start(handle);
	}
}

/**
 * input_release_device - release previously grabbed device
 * @handle: input handle that owns the device
 *
 * Releases previously grabbed device so that other input handles can
 * start receiving input events. Upon release all handlers attached
 * to the device have their start() method called so they have a change
 * to synchronize device state with the rest of the system.
 */
void input_release_device(struct input_handle *handle)
{
	struct input_dev *dev = handle->dev;

	mutex_lock(&dev->mutex);
	__input_release_device(handle);
	mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL(input_release_device);

/**
 * input_open_device - open input device
 * @handle: handle through which device is being accessed
 *
 * This function should be called by input handlers when they
 * want to start receive events from given input device.
 */
int input_open_device(struct input_handle *handle)
{
	struct input_dev *dev = handle->dev;
	int retval;

	retval = mutex_lock_interruptible(&dev->mutex);
	if (retval)
		return retval;

	if (dev->going_away) {
		retval = -ENODEV;
		goto out;
	}

	handle->open++;

	if (!dev->users++ && dev->open)
		retval = dev->open(dev);

	if (retval) {
		dev->users--;
		if (!--handle->open) {
			/*
			 * Make sure we are not delivering any more events
			 * through this handle
			 */
			synchronize_rcu();
		}
	}

 out:
	mutex_unlock(&dev->mutex);
	return retval;
}
EXPORT_SYMBOL(input_open_device);

int input_flush_device(struct input_handle *handle, struct file *file)
{
	struct input_dev *dev = handle->dev;
	int retval;

	retval = mutex_lock_interruptible(&dev->mutex);
	if (retval)
		return retval;

	if (dev->flush)
		retval = dev->flush(dev, file);

	mutex_unlock(&dev->mutex);
	return retval;
}
EXPORT_SYMBOL(input_flush_device);

/**
 * input_close_device - close input device
 * @handle: handle through which device is being accessed
 *
 * This function should be called by input handlers when they
 * want to stop receive events from given input device.
 */
void input_close_device(struct input_handle *handle)
{
	struct input_dev *dev = handle->dev;

	mutex_lock(&dev->mutex);

	__input_release_device(handle);

	if (!--dev->users && dev->close)
		dev->close(dev);

	if (!--handle->open) {
		/*
		 * synchronize_rcu() makes sure that input_pass_event()
		 * completed and that no more input events are delivered
		 * through this handle
		 */
		synchronize_rcu();
	}

	mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL(input_close_device);

/*
 * Simulate keyup events for all keys that are marked as pressed.
 * The function must be called with dev->event_lock held.
 */
static void input_dev_release_keys(struct input_dev *dev)
{
	bool need_sync = false;
	int code;

	if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
		for_each_set_bit(code, dev->key, KEY_CNT) {
			input_pass_event(dev, EV_KEY, code, 0);
			need_sync = true;
		}

		if (need_sync)
			input_pass_event(dev, EV_SYN, SYN_REPORT, 1);

		memset(dev->key, 0, sizeof(dev->key));
	}
}

/*
 * Prepare device for unregistering
 */
static void input_disconnect_device(struct input_dev *dev)
{
	struct input_handle *handle;

	/*
	 * Mark device as going away. Note that we take dev->mutex here
	 * not to protect access to dev->going_away but rather to ensure
	 * that there are no threads in the middle of input_open_device()
	 */
	mutex_lock(&dev->mutex);
	dev->going_away = true;
	mutex_unlock(&dev->mutex);

	spin_lock_irq(&dev->event_lock);

	/*
	 * Simulate keyup events for all pressed keys so that handlers
	 * are not left with "stuck" keys. The driver may continue
	 * generate events even after we done here but they will not
	 * reach any handlers.
	 */
	input_dev_release_keys(dev);

	list_for_each_entry(handle, &dev->h_list, d_node)
		handle->open = 0;

	spin_unlock_irq(&dev->event_lock);
}

/**
 * input_scancode_to_scalar() - converts scancode in &struct input_keymap_entry
 * @ke: keymap entry containing scancode to be converted.
 * @scancode: pointer to the location where converted scancode should
 *	be stored.
 *
 * This function is used to convert scancode stored in &struct keymap_entry
 * into scalar form understood by legacy keymap handling methods. These
 * methods expect scancodes to be represented as 'unsigned int'.
 */
int input_scancode_to_scalar(const struct input_keymap_entry *ke,
			     unsigned int *scancode)
{
	switch (ke->len) {
	case 1:
		*scancode = *((u8 *)ke->scancode);
		break;

	case 2:
		*scancode = *((u16 *)ke->scancode);
		break;

	case 4:
		*scancode = *((u32 *)ke->scancode);
		break;

	default:
		return -EINVAL;
	}

	return 0;
}
EXPORT_SYMBOL(input_scancode_to_scalar);

/*
 * Those routines handle the default case where no [gs]etkeycode() is
 * defined. In this case, an array indexed by the scancode is used.
 */

static unsigned int input_fetch_keycode(struct input_dev *dev,
					unsigned int index)
{
	switch (dev->keycodesize) {
	case 1:
		return ((u8 *)dev->keycode)[index];

	case 2:
		return ((u16 *)dev->keycode)[index];

	default:
		return ((u32 *)dev->keycode)[index];
	}
}

static int input_default_getkeycode(struct input_dev *dev,
				    struct input_keymap_entry *ke)
{
	unsigned int index;
	int error;

	if (!dev->keycodesize)
		return -EINVAL;

	if (ke->flags & INPUT_KEYMAP_BY_INDEX)
		index = ke->index;
	else {
		error = input_scancode_to_scalar(ke, &index);
		if (error)
			return error;
	}

	if (index >= dev->keycodemax)
		return -EINVAL;

	ke->keycode = input_fetch_keycode(dev, index);
	ke->index = index;
	ke->len = sizeof(index);
	memcpy(ke->scancode, &index, sizeof(index));

	return 0;
}

static int input_default_setkeycode(struct input_dev *dev,
				    const struct input_keymap_entry *ke,
				    unsigned int *old_keycode)
{
	unsigned int index;
	int error;
	int i;

	if (!dev->keycodesize)
		return -EINVAL;

	if (ke->flags & INPUT_KEYMAP_BY_INDEX) {
		index = ke->index;
	} else {
		error = input_scancode_to_scalar(ke, &index);
		if (error)
			return error;
	}

	if (index >= dev->keycodemax)
		return -EINVAL;

	if (dev->keycodesize < sizeof(ke->keycode) &&
			(ke->keycode >> (dev->keycodesize * 8)))
		return -EINVAL;

	switch (dev->keycodesize) {
		case 1: {
			u8 *k = (u8 *)dev->keycode;
			*old_keycode = k[index];
			k[index] = ke->keycode;
			break;
		}
		case 2: {
			u16 *k = (u16 *)dev->keycode;
			*old_keycode = k[index];
			k[index] = ke->keycode;
			break;
		}
		default: {
			u32 *k = (u32 *)dev->keycode;
			*old_keycode = k[index];
			k[index] = ke->keycode;
			break;
		}
	}

	__clear_bit(*old_keycode, dev->keybit);
	__set_bit(ke->keycode, dev->keybit);

	for (i = 0; i < dev->keycodemax; i++) {
		if (input_fetch_keycode(dev, i) == *old_keycode) {
			__set_bit(*old_keycode, dev->keybit);
			break; /* Setting the bit twice is useless, so break */
		}
	}

	return 0;
}

/**
 * input_get_keycode - retrieve keycode currently mapped to a given scancode
 * @dev: input device which keymap is being queried
 * @ke: keymap entry
 *
 * This function should be called by anyone interested in retrieving current
 * keymap. Presently evdev handlers use it.
 */
int input_get_keycode(struct input_dev *dev, struct input_keymap_entry *ke)
{
	unsigned long flags;
	int retval;

	spin_lock_irqsave(&dev->event_lock, flags);
	retval = dev->getkeycode(dev, ke);
	spin_unlock_irqrestore(&dev->event_lock, flags);

	return retval;
}
EXPORT_SYMBOL(input_get_keycode);

/**
 * input_set_keycode - attribute a keycode to a given scancode
 * @dev: input device which keymap is being updated
 * @ke: new keymap entry
 *
 * This function should be called by anyone needing to update current
 * keymap. Presently keyboard and evdev handlers use it.
 */
int input_set_keycode(struct input_dev *dev,
		      const struct input_keymap_entry *ke)
{
	unsigned long flags;
	unsigned int old_keycode;
	int retval;

	if (ke->keycode > KEY_MAX)
		return -EINVAL;

	spin_lock_irqsave(&dev->event_lock, flags);

	retval = dev->setkeycode(dev, ke, &old_keycode);
	if (retval)
		goto out;

	/* Make sure KEY_RESERVED did not get enabled. */
	__clear_bit(KEY_RESERVED, dev->keybit);

	/*
	 * Simulate keyup event if keycode is not present
	 * in the keymap anymore
	 */
	if (test_bit(EV_KEY, dev->evbit) &&
	    !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
	    __test_and_clear_bit(old_keycode, dev->key)) {
		struct input_value vals[] =  {
			{ EV_KEY, old_keycode, 0 },
			input_value_sync
		};

		input_pass_values(dev, vals, ARRAY_SIZE(vals));
	}

 out:
	spin_unlock_irqrestore(&dev->event_lock, flags);

	return retval;
}
EXPORT_SYMBOL(input_set_keycode);

static const struct input_device_id *input_match_device(struct input_handler *handler,
							struct input_dev *dev)
{
	const struct input_device_id *id;

	for (id = handler->id_table; id->flags || id->driver_info; id++) {

		if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)
			if (id->bustype != dev->id.bustype)
				continue;

		if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
			if (id->vendor != dev->id.vendor)
				continue;

		if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
			if (id->product != dev->id.product)
				continue;

		if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
			if (id->version != dev->id.version)
				continue;

		if (!bitmap_subset(id->evbit, dev->evbit, EV_MAX))
			continue;

		if (!bitmap_subset(id->keybit, dev->keybit, KEY_MAX))
			continue;

		if (!bitmap_subset(id->relbit, dev->relbit, REL_MAX))
			continue;

		if (!bitmap_subset(id->absbit, dev->absbit, ABS_MAX))
			continue;

		if (!bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX))
			continue;

		if (!bitmap_subset(id->ledbit, dev->ledbit, LED_MAX))
			continue;

		if (!bitmap_subset(id->sndbit, dev->sndbit, SND_MAX))
			continue;

		if (!bitmap_subset(id->ffbit, dev->ffbit, FF_MAX))
			continue;

		if (!bitmap_subset(id->swbit, dev->swbit, SW_MAX))
			continue;

		if (!handler->match || handler->match(handler, dev))
			return id;
	}

	return NULL;
}

static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
{
	const struct input_device_id *id;
	int error;

	id = input_match_device(handler, dev);
	if (!id)
		return -ENODEV;

	error = handler->connect(handler, dev, id);
	if (error && error != -ENODEV)
		pr_err("failed to attach handler %s to device %s, error: %d\n",
		       handler->name, kobject_name(&dev->dev.kobj), error);

	return error;
}

#ifdef CONFIG_COMPAT

static int input_bits_to_string(char *buf, int buf_size,
				unsigned long bits, bool skip_empty)
{
	int len = 0;

	if (in_compat_syscall()) {
		u32 dword = bits >> 32;
		if (dword || !skip_empty)
			len += snprintf(buf, buf_size, "%x ", dword);

		dword = bits & 0xffffffffUL;
		if (dword || !skip_empty || len)
			len += snprintf(buf + len, max(buf_size - len, 0),
					"%x", dword);
	} else {
		if (bits || !skip_empty)
			len += snprintf(buf, buf_size, "%lx", bits);
	}

	return len;
}

#else /* !CONFIG_COMPAT */

static int input_bits_to_string(char *buf, int buf_size,
				unsigned long bits, bool skip_empty)
{
	return bits || !skip_empty ?
		snprintf(buf, buf_size, "%lx", bits) : 0;
}

#endif

#ifdef CONFIG_PROC_FS

static struct proc_dir_entry *proc_bus_input_dir;
static DECLARE_WAIT_QUEUE_HEAD(input_devices_poll_wait);
static int input_devices_state;

static inline void input_wakeup_procfs_readers(void)
{
	input_devices_state++;
	wake_up(&input_devices_poll_wait);
}

static unsigned int input_proc_devices_poll(struct file *file, poll_table *wait)
{
	poll_wait(file, &input_devices_poll_wait, wait);
	if (file->f_version != input_devices_state) {
		file->f_version = input_devices_state;
		return POLLIN | POLLRDNORM;
	}

	return 0;
}

union input_seq_state {
	struct {
		unsigned short pos;
		bool mutex_acquired;
	};
	void *p;
};

static void *input_devices_seq_start(struct seq_file *seq, loff_t *pos)
{
	union input_seq_state *state = (union input_seq_state *)&seq->private;
	int error;

	/* We need to fit into seq->private pointer */
	BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));

	error = mutex_lock_interruptible(&input_mutex);
	if (error) {
		state->mutex_acquired = false;
		return ERR_PTR(error);
	}

	state->mutex_acquired = true;

	return seq_list_start(&input_dev_list, *pos);
}

static void *input_devices_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	return seq_list_next(v, &input_dev_list, pos);
}

static void input_seq_stop(struct seq_file *seq, void *v)
{
	union input_seq_state *state = (union input_seq_state *)&seq->private;

	if (state->mutex_acquired)
		mutex_unlock(&input_mutex);
}

static void input_seq_print_bitmap(struct seq_file *seq, const char *name,
				   unsigned long *bitmap, int max)
{
	int i;
	bool skip_empty = true;
	char buf[18];

	seq_printf(seq, "B: %s=", name);

	for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
		if (input_bits_to_string(buf, sizeof(buf),
					 bitmap[i], skip_empty)) {
			skip_empty = false;
			seq_printf(seq, "%s%s", buf, i > 0 ? " " : "");
		}
	}

	/*
	 * If no output was produced print a single 0.
	 */
	if (skip_empty)
		seq_puts(seq, "0");

	seq_putc(seq, '\n');
}

static int input_devices_seq_show(struct seq_file *seq, void *v)
{
	struct input_dev *dev = container_of(v, struct input_dev, node);
	const char *path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
	struct input_handle *handle;

	seq_printf(seq, "I: Bus=%04x Vendor=%04x Product=%04x Version=%04x\n",
		   dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version);

	seq_printf(seq, "N: Name=\"%s\"\n", dev->name ? dev->name : "");
	seq_printf(seq, "P: Phys=%s\n", dev->phys ? dev->phys : "");
	seq_printf(seq, "S: Sysfs=%s\n", path ? path : "");
	seq_printf(seq, "U: Uniq=%s\n", dev->uniq ? dev->uniq : "");
	seq_printf(seq, "H: Handlers=");

	list_for_each_entry(handle, &dev->h_list, d_node)
		seq_printf(seq, "%s ", handle->name);
	seq_putc(seq, '\n');

	input_seq_print_bitmap(seq, "PROP", dev->propbit, INPUT_PROP_MAX);

	input_seq_print_bitmap(seq, "EV", dev->evbit, EV_MAX);
	if (test_bit(EV_KEY, dev->evbit))
		input_seq_print_bitmap(seq, "KEY", dev->keybit, KEY_MAX);
	if (test_bit(EV_REL, dev->evbit))
		input_seq_print_bitmap(seq, "REL", dev->relbit, REL_MAX);
	if (test_bit(EV_ABS, dev->evbit))
		input_seq_print_bitmap(seq, "ABS", dev->absbit, ABS_MAX);
	if (test_bit(EV_MSC, dev->evbit))
		input_seq_print_bitmap(seq, "MSC", dev->mscbit, MSC_MAX);
	if (test_bit(EV_LED, dev->evbit))
		input_seq_print_bitmap(seq, "LED", dev->ledbit, LED_MAX);
	if (test_bit(EV_SND, dev->evbit))
		input_seq_print_bitmap(seq, "SND", dev->sndbit, SND_MAX);
	if (test_bit(EV_FF, dev->evbit))
		input_seq_print_bitmap(seq, "FF", dev->ffbit, FF_MAX);
	if (test_bit(EV_SW, dev->evbit))
		input_seq_print_bitmap(seq, "SW", dev->swbit, SW_MAX);

	seq_putc(seq, '\n');

	kfree(path);
	return 0;
}

static const struct seq_operations input_devices_seq_ops = {
	.start	= input_devices_seq_start,
	.next	= input_devices_seq_next,
	.stop	= input_seq_stop,
	.show	= input_devices_seq_show,
};

static int input_proc_devices_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &input_devices_seq_ops);
}

static const struct file_operations input_devices_fileops = {
	.owner		= THIS_MODULE,
	.open		= input_proc_devices_open,
	.poll		= input_proc_devices_poll,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static void *input_handlers_seq_start(struct seq_file *seq, loff_t *pos)
{
	union input_seq_state *state = (union input_seq_state *)&seq->private;
	int error;

	/* We need to fit into seq->private pointer */
	BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));

	error = mutex_lock_interruptible(&input_mutex);
	if (error) {
		state->mutex_acquired = false;
		return ERR_PTR(error);
	}

	state->mutex_acquired = true;
	state->pos = *pos;

	return seq_list_start(&input_handler_list, *pos);
}

static void *input_handlers_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	union input_seq_state *state = (union input_seq_state *)&seq->private;

	state->pos = *pos + 1;
	return seq_list_next(v, &input_handler_list, pos);
}

static int input_handlers_seq_show(struct seq_file *seq, void *v)
{
	struct input_handler *handler = container_of(v, struct input_handler, node);
	union input_seq_state *state = (union input_seq_state *)&seq->private;

	seq_printf(seq, "N: Number=%u Name=%s", state->pos, handler->name);
	if (handler->filter)
		seq_puts(seq, " (filter)");
	if (handler->legacy_minors)
		seq_printf(seq, " Minor=%d", handler->minor);
	seq_putc(seq, '\n');

	return 0;
}

static const struct seq_operations input_handlers_seq_ops = {
	.start	= input_handlers_seq_start,
	.next	= input_handlers_seq_next,
	.stop	= input_seq_stop,
	.show	= input_handlers_seq_show,
};

static int input_proc_handlers_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &input_handlers_seq_ops);
}

static const struct file_operations input_handlers_fileops = {
	.owner		= THIS_MODULE,
	.open		= input_proc_handlers_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int __init input_proc_init(void)
{
	struct proc_dir_entry *entry;

	proc_bus_input_dir = proc_mkdir("bus/input", NULL);
	if (!proc_bus_input_dir)
		return -ENOMEM;

	entry = proc_create("devices", 0, proc_bus_input_dir,
			    &input_devices_fileops);
	if (!entry)
		goto fail1;

	entry = proc_create("handlers", 0, proc_bus_input_dir,
			    &input_handlers_fileops);
	if (!entry)
		goto fail2;

	return 0;

 fail2:	remove_proc_entry("devices", proc_bus_input_dir);
 fail1: remove_proc_entry("bus/input", NULL);
	return -ENOMEM;
}

static void input_proc_exit(void)
{
	remove_proc_entry("devices", proc_bus_input_dir);
	remove_proc_entry("handlers", proc_bus_input_dir);
	remove_proc_entry("bus/input", NULL);
}

#else /* !CONFIG_PROC_FS */
static inline void input_wakeup_procfs_readers(void) { }
static inline int input_proc_init(void) { return 0; }
static inline void input_proc_exit(void) { }
#endif

#define INPUT_DEV_STRING_ATTR_SHOW(name)				\
static ssize_t input_dev_show_##name(struct device *dev,		\
				     struct device_attribute *attr,	\
				     char *buf)				\
{									\
	struct input_dev *input_dev = to_input_dev(dev);		\
									\
	return scnprintf(buf, PAGE_SIZE, "%s\n",			\
			 input_dev->name ? input_dev->name : "");	\
}									\
static DEVICE_ATTR(name, S_IRUGO, input_dev_show_##name, NULL)

INPUT_DEV_STRING_ATTR_SHOW(name);
INPUT_DEV_STRING_ATTR_SHOW(phys);
INPUT_DEV_STRING_ATTR_SHOW(uniq);

static int input_print_modalias_bits(char *buf, int size,
				     char name, unsigned long *bm,
				     unsigned int min_bit, unsigned int max_bit)
{
	int len = 0, i;

	len += snprintf(buf, max(size, 0), "%c", name);
	for (i = min_bit; i < max_bit; i++)
		if (bm[BIT_WORD(i)] & BIT_MASK(i))
			len += snprintf(buf + len, max(size - len, 0), "%X,", i);
	return len;
}

static int input_print_modalias(char *buf, int size, struct input_dev *id,
				int add_cr)
{
	int len;

	len = snprintf(buf, max(size, 0),
		       "input:b%04Xv%04Xp%04Xe%04X-",
		       id->id.bustype, id->id.vendor,
		       id->id.product, id->id.version);

	len += input_print_modalias_bits(buf + len, size - len,
				'e', id->evbit, 0, EV_MAX);
	len += input_print_modalias_bits(buf + len, size - len,
				'k', id->keybit, KEY_MIN_INTERESTING, KEY_MAX);
	len += input_print_modalias_bits(buf + len, size - len,
				'r', id->relbit, 0, REL_MAX);
	len += input_print_modalias_bits(buf + len, size - len,
				'a', id->absbit, 0, ABS_MAX);
	len += input_print_modalias_bits(buf + len, size - len,
				'm', id->mscbit, 0, MSC_MAX);
	len += input_print_modalias_bits(buf + len, size - len,
				'l', id->ledbit, 0, LED_MAX);
	len += input_print_modalias_bits(buf + len, size - len,
				's', id->sndbit, 0, SND_MAX);
	len += input_print_modalias_bits(buf + len, size - len,
				'f', id->ffbit, 0, FF_MAX);
	len += input_print_modalias_bits(buf + len, size - len,
				'w', id->swbit, 0, SW_MAX);

	if (add_cr)
		len += snprintf(buf + len, max(size - len, 0), "\n");

	return len;
}

static ssize_t input_dev_show_modalias(struct device *dev,
				       struct device_attribute *attr,
				       char *buf)
{
	struct input_dev *id = to_input_dev(dev);
	ssize_t len;

	len = input_print_modalias(buf, PAGE_SIZE, id, 1);

	return min_t(int, len, PAGE_SIZE);
}
static DEVICE_ATTR(modalias, S_IRUGO, input_dev_show_modalias, NULL);

static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
			      int max, int add_cr);

static ssize_t input_dev_show_properties(struct device *dev,
					 struct device_attribute *attr,
					 char *buf)
{
	struct input_dev *input_dev = to_input_dev(dev);
	int len = input_print_bitmap(buf, PAGE_SIZE, input_dev->propbit,
				     INPUT_PROP_MAX