Initial import

1 files changed, 2451 insertions, 0 deletions

diff --git a/drivers/input/input.c b/drivers/input/input.c
new file mode 100644
index 000000000..cc357f151
--- /dev/null
+++ b/drivers/input/input.c
@@ -0,0 +1,2451 @@
+/*
+ * 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();
+
+	add_input_randomness(vals->type, vals->code, vals->value);
+
+	/* 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;
+
+	disposition = input_get_disposition(dev, 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)
+{
+	int code;
+
+	if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
+		for (code = 0; code <= KEY_MAX; code++) {
+			if (is_event_supported(code, dev->keybit, KEY_MAX) &&
+			    __test_and_clear_bit(code, dev->key)) {
+				input_pass_event(dev, EV_KEY, code, 0);
+			}
+		}
+		input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
+	}
+}
+
+/*
+ * 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 (INPUT_COMPAT_TEST) {
+		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, true);
+	return min_t(int, len, PAGE_SIZE);
+}
+static DEVICE_ATTR(properties, S_IRUGO, input_dev_show_properties, NULL);
+
+static struct attribute *input_dev_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_phys.attr,
+	&dev_attr_uniq.attr,
+	&dev_attr_modalias.attr,
+	&dev_attr_properties.attr,
+	NULL
+};
+
+static struct attribute_group input_dev_attr_group = {
+	.attrs	= input_dev_attrs,
+};
+
+#define INPUT_DEV_ID_ATTR(name)						\
+static ssize_t input_dev_show_id_##name(struct device *dev,		\
+					struct device_attribute *attr,	\
+					char *buf)			\
+{									\
+	struct input_dev *input_dev = to_input_dev(dev);		\
+	return scnprintf(buf, PAGE_SIZE, "%04x\n", input_dev->id.name);	\
+}									\
+static DEVICE_ATTR(name, S_IRUGO, input_dev_show_id_##name, NULL)
+
+INPUT_DEV_ID_ATTR(bustype);
+INPUT_DEV_ID_ATTR(vendor);
+INPUT_DEV_ID_ATTR(product);
+INPUT_DEV_ID_ATTR(version);
+
+static struct attribute *input_dev_id_attrs[] = {
+	&dev_attr_bustype.attr,
+	&dev_attr_vendor.attr,
+	&dev_attr_product.attr,
+	&dev_attr_version.attr,
+	NULL
+};
+
+static struct attribute_group input_dev_id_attr_group = {
+	.name	= "id",
+	.attrs	= input_dev_id_attrs,
+};
+
+static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
+			      int max, int add_cr)
+{
+	int i;
+	int len = 0;
+	bool skip_empty = true;
+
+	for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
+		len += input_bits_to_string(buf + len, max(buf_size - len, 0),
+					    bitmap[i], skip_empty);
+		if (len) {
+			skip_empty = false;
+			if (i > 0)
+				len += snprintf(buf + len, max(buf_size - len, 0), " ");
+		}
+	}
+
+	/*
+	 * If no output was produced print a single 0.
+	 */
+	if (len == 0)
+		len = snprintf(buf, buf_size, "%d", 0);
+
+	if (add_cr)
+		len += snprintf(buf + len, max(buf_size - len, 0), "\n");
+
+	return len;
+}
+
+#define INPUT_DEV_CAP_ATTR(ev, bm)					\
+static ssize_t input_dev_show_cap_##bm(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->bm##bit, ev##_MAX,	\
+				     true);				\
+	return min_t(int, len, PAGE_SIZE);				\
+}									\
+static DEVICE_ATTR(bm, S_IRUGO, input_dev_show_cap_##bm, NULL)
+
+INPUT_DEV_CAP_ATTR(EV, ev);
+INPUT_DEV_CAP_ATTR(KEY, key);
+INPUT_DEV_CAP_ATTR(REL, rel);
+INPUT_DEV_CAP_ATTR(ABS, abs);
+INPUT_DEV_CAP_ATTR(MSC, msc);
+INPUT_DEV_CAP_ATTR(LED, led);
+INPUT_DEV_CAP_ATTR(SND, snd);
+INPUT_DEV_CAP_ATTR(FF, ff);
+INPUT_DEV_CAP_ATTR(SW, sw);
+
+static struct attribute *input_dev_caps_attrs[] = {
+	&dev_attr_ev.attr,
+	&dev_attr_key.attr,
+	&dev_attr_rel.attr,
+	&dev_attr_abs.attr,
+	&dev_attr_msc.attr,
+	&dev_attr_led.attr,
+	&dev_attr_snd.attr,
+	&dev_attr_ff.attr,
+	&dev_attr_sw.attr,
+	NULL
+};
+
+static struct attribute_group input_dev_caps_attr_group = {
+	.name	= "capabilities",
+	.attrs	= input_dev_caps_attrs,
+};
+
+static const struct attribute_group *input_dev_attr_groups[] = {
+	&input_dev_attr_group,
+	&input_dev_id_attr_group,
+	&input_dev_caps_attr_group,
+	NULL
+};
+
+static void input_dev_release(struct device *device)
+{
+	struct input_dev *dev = to_input_dev(device);
+
+	input_ff_destroy(dev);
+	input_mt_destroy_slots(dev);
+	kfree(dev->absinfo);
+	kfree(dev->vals);
+	kfree(dev);
+
+	module_put(THIS_MODULE);
+}
+
+/*
+ * Input uevent interface - loading event handlers based on
+ * device bitfields.
+ */
+static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
+				   const char *name, unsigned long *bitmap, int max)
+{
+	int len;
+
+	if (add_uevent_var(env, "%s", name))
+		return -ENOMEM;
+
+	len = input_print_bitmap(&env->buf[env->buflen - 1],
+				 sizeof(env->buf) - env->buflen,
+				 bitmap, max, false);
+	if (len >= (sizeof(env->buf) - env->buflen))
+		return -ENOMEM;
+
+	env->buflen += len;
+	return 0;
+}
+
+static int input_add_uevent_modalias_var(struct kobj_uevent_env *env,
+					 struct input_dev *dev)
+{
+	int len;
+
+	if (add_uevent_var(env, "MODALIAS="))
+		return -ENOMEM;
+
+	len = input_print_modalias(&env->buf[env->buflen - 1],
+				   sizeof(env->buf) - env->buflen,
+				   dev, 0);
+	if (len >= (sizeof(env->buf) - env->buflen))
+		return -ENOMEM;
+
+	env->buflen += len;
+	return 0;
+}
+
+#define INPUT_ADD_HOTPLUG_VAR(fmt, val...)				\
+	do {								\
+		int err = add_uevent_var(env, fmt, val);		\
+		if (err)						\
+			return err;					\
+	} while (0)
+
+#define INPUT_ADD_HOTPLUG_BM_VAR(name, bm, max)				\
+	do {								\
+		int err = input_add_uevent_bm_var(env, name, bm, max);	\
+		if (err)						\
+			return err;					\
+	} while (0)
+
+#define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev)				\
+	do {								\
+		int err = input_add_uevent_modalias_var(env, dev);	\
+		if (err)						\
+			return err;					\
+	} while (0)
+
+static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
+{
+	struct input_dev *dev = to_input_dev(device);
+
+	INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
+				dev->id.bustype, dev->id.vendor,
+				dev->id.product, dev->id.version);
+	if (dev->name)
+		INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name);
+	if (dev->phys)
+		INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys);
+	if (dev->uniq)
+		INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq);
+
+	INPUT_ADD_HOTPLUG_BM_VAR("PROP=", dev->propbit, INPUT_PROP_MAX);
+
+	INPUT_ADD_HOTPLUG_BM_VAR("EV=", dev->evbit, EV_MAX);
+	if (test_bit(EV_KEY, dev->evbit))
+		INPUT_ADD_HOTPLUG_BM_VAR("KEY=", dev->keybit, KEY_MAX);
+	if (test_bit(EV_REL, dev->evbit))
+		INPUT_ADD_HOTPLUG_BM_VAR("REL=", dev->relbit, REL_MAX);
+	if (test_bit(EV_ABS, dev->evbit))
+		INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX);
+	if (test_bit(EV_MSC, dev->evbit))
+		INPUT_ADD_HOTPLUG_BM_VAR("MSC=", dev->mscbit, MSC_MAX);
+	if (test_bit(EV_LED, dev->evbit))
+		INPUT_ADD_HOTPLUG_BM_VAR("LED=", dev->ledbit, LED_MAX);
+	if (test_bit(EV_SND, dev->evbit))
+		INPUT_ADD_HOTPLUG_BM_VAR("SND=", dev->sndbit, SND_MAX);
+	if (test_bit(EV_FF, dev->evbit))
+		INPUT_ADD_HOTPLUG_BM_VAR("FF=", dev->ffbit, FF_MAX);
+	if (test_bit(EV_SW, dev->evbit))
+		INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX);
+
+	INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);
+
+	return 0;
+}
+
+#define INPUT_DO_TOGGLE(dev, type, bits, on)				\
+	do {								\
+		int i;							\
+		bool active;						\
+									\
+		if (!test_bit(EV_##type, dev->evbit))			\
+			break;						\
+									\
+		for (i = 0; i < type##_MAX; i++) {			\
+			if (!test_bit(i, dev->bits##bit))		\
+				continue;				\
+									\
+			active = test_bit(i, dev->bits);		\
+			if (!active && !on)				\
+				continue;				\
+									\
+			dev->event(dev, EV_##type, i, on ? active : 0);	\
+		}							\
+	} while (0)
+
+static void input_dev_toggle(struct input_dev *dev, bool activate)
+{
+	if (!dev->event)
+		return;
+
+	INPUT_DO_TOGGLE(dev, LED, led, activate);
+	INPUT_DO_TOGGLE(dev, SND, snd, activate);
+
+	if (activate && test_bit(EV_REP, dev->evbit)) {
+		dev->event(dev, EV_REP, REP_PERIOD, dev->rep[REP_PERIOD]);
+		dev->event(dev, EV_REP, REP_DELAY, dev->rep[REP_DELAY]);
+	}
+}
+
+/**
+ * input_reset_device() - reset/restore the state of input device
+ * @dev: input device whose state needs to be reset
+ *
+ * This function tries to reset the state of an opened input device and
+ * bring internal state and state if the hardware in sync with each other.
+ * We mark all keys as released, restore LED state, repeat rate, etc.
+ */
+void input_reset_device(struct input_dev *dev)
+{
+	unsigned long flags;
+
+	mutex_lock(&dev->mutex);
+	spin_lock_irqsave(&dev->event_lock, flags);
+
+	input_dev_toggle(dev, true);
+	input_dev_release_keys(dev);
+
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+	mutex_unlock(&dev->mutex);
+}
+EXPORT_SYMBOL(input_reset_device);
+
+#ifdef CONFIG_PM_SLEEP
+static int input_dev_suspend(struct device *dev)
+{
+	struct input_dev *input_dev = to_input_dev(dev);
+
+	spin_lock_irq(&input_dev->event_lock);
+
+	/*
+	 * Keys that are pressed now are unlikely to be
+	 * still pressed when we resume.
+	 */
+	input_dev_release_keys(input_dev);
+
+	/* Turn off LEDs and sounds, if any are active. */
+	input_dev_toggle(input_dev, false);
+
+	spin_unlock_irq(&input_dev->event_lock);
+
+	return 0;
+}
+
+static int input_dev_resume(struct device *dev)
+{
+	struct input_dev *input_dev = to_input_dev(dev);
+
+	spin_lock_irq(&input_dev->event_lock);
+
+	/* Restore state of LEDs and sounds, if any were active. */
+	input_dev_toggle(input_dev, true);
+
+	spin_unlock_irq(&input_dev->event_lock);
+
+	return 0;
+}
+
+static int input_dev_freeze(struct device *dev)
+{
+	struct input_dev *input_dev = to_input_dev(dev);
+
+	spin_lock_irq(&input_dev->event_lock);
+
+	/*
+	 * Keys that are pressed now are unlikely to be
+	 * still pressed when we resume.
+	 */
+	input_dev_release_keys(input_dev);
+
+	spin_unlock_irq(&input_dev->event_lock);
+
+	return 0;
+}
+
+static int input_dev_poweroff(struct device *dev)
+{
+	struct input_dev *input_dev = to_input_dev(dev);
+
+	spin_lock_irq(&input_dev->event_lock);
+
+	/* Turn off LEDs and sounds, if any are active. */
+	input_dev_toggle(input_dev, false);
+
+	spin_unlock_irq(&input_dev->event_lock);
+
+	return 0;
+}
+
+static const struct dev_pm_ops input_dev_pm_ops = {
+	.suspend	= input_dev_suspend,
+	.resume		= input_dev_resume,
+	.freeze		= input_dev_freeze,
+	.poweroff	= input_dev_poweroff,
+	.restore	= input_dev_resume,
+};
+#endif /* CONFIG_PM */
+
+static struct device_type input_dev_type = {
+	.groups		= input_dev_attr_groups,
+	.release	= input_dev_release,
+	.uevent		= input_dev_uevent,
+#ifdef CONFIG_PM_SLEEP
+	.pm		= &input_dev_pm_ops,
+#endif
+};
+
+static char *input_devnode(struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "input/%s", dev_name(dev));
+}
+
+struct class input_class = {
+	.name		= "input",
+	.devnode	= input_devnode,
+};
+EXPORT_SYMBOL_GPL(input_class);
+
+/**
+ * input_allocate_device - allocate memory for new input device
+ *
+ * Returns prepared struct input_dev or %NULL.
+ *
+ * NOTE: Use input_free_device() to free devices that have not been
+ * registered; input_unregister_device() should be used for already
+ * registered devices.
+ */
+struct input_dev *input_allocate_device(void)
+{
+	static atomic_t input_no = ATOMIC_INIT(-1);
+	struct input_dev *dev;
+
+	dev = kzalloc(sizeof(struct input_dev), GFP_KERNEL);
+	if (dev) {
+		dev->dev.type = &input_dev_type;
+		dev->dev.class = &input_class;
+		device_initialize(&dev->dev);
+		mutex_init(&dev->mutex);
+		spin_lock_init(&dev->event_lock);
+		init_timer(&dev->timer);
+		INIT_LIST_HEAD(&dev->h_list);
+		INIT_LIST_HEAD(&dev->node);
+
+		dev_set_name(&dev->dev, "input%lu",
+			     (unsigned long)atomic_inc_return(&input_no));
+
+		__module_get(THIS_MODULE);
+	}
+
+	return dev;
+}
+EXPORT_SYMBOL(input_allocate_device);
+
+struct input_devres {
+	struct input_dev *input;
+};
+
+static int devm_input_device_match(struct device *dev, void *res, void *data)
+{
+	struct input_devres *devres = res;
+
+	return devres->input == data;
+}
+
+static void devm_input_device_release(struct device *dev, void *res)
+{
+	struct input_devres *devres = res;
+	struct input_dev *input = devres->input;
+
+	dev_dbg(dev, "%s: dropping reference to %s\n",
+		__func__, dev_name(&input->dev));
+	input_put_device(input);
+}
+
+/**
+ * devm_input_allocate_device - allocate managed input device
+ * @dev: device owning the input device being created
+ *
+ * Returns prepared struct input_dev or %NULL.
+ *
+ * Managed input devices do not need to be explicitly unregistered or
+ * freed as it will be done automatically when owner device unbinds from
+ * its driver (or binding fails). Once managed input device is allocated,
+ * it is ready to be set up and registered in the same fashion as regular
+ * input device. There are no special devm_input_device_[un]register()
+ * variants, regular ones work with both managed and unmanaged devices,
+ * should you need them. In most cases however, managed input device need
+ * not be explicitly unregistered or freed.
+ *
+ * NOTE: the owner device is set up as parent of input device and users
+ * should not override it.
+ */
+struct input_dev *devm_input_allocate_device(struct device *dev)
+{
+	struct input_dev *input;
+	struct input_devres *devres;
+
+	devres = devres_alloc(devm_input_device_release,
+			      sizeof(struct input_devres), GFP_KERNEL);
+	if (!devres)
+		return NULL;
+
+	input = input_allocate_device();
+	if (!input) {
+		devres_free(devres);
+		return NULL;
+	}
+
+	input->dev.parent = dev;
+	input->devres_managed = true;
+
+	devres->input = input;
+	devres_add(dev, devres);
+
+	return input;
+}
+EXPORT_SYMBOL(devm_input_allocate_device);
+
+/**
+ * input_free_device - free memory occupied by input_dev structure
+ * @dev: input device to free
+ *
+ * This function should only be used if input_register_device()
+ * was not called yet or if it failed. Once device was registered
+ * use input_unregister_device() and memory will be freed once last
+ * reference to the device is dropped.
+ *
+ * Device should be allocated by input_allocate_device().
+ *
+ * NOTE: If there are references to the input device then memory
+ * will not be freed until last reference is dropped.
+ */
+void input_free_device(struct input_dev *dev)
+{
+	if (dev) {
+		if (dev->devres_managed)
+			WARN_ON(devres_destroy(dev->dev.parent,
+						devm_input_device_release,
+						devm_input_device_match,
+						dev));
+		input_put_device(dev);
+	}
+}
+EXPORT_SYMBOL(input_free_device);
+
+/**
+ * input_set_capability - mark device as capable of a certain event
+ * @dev: device that is capable of emitting or accepting event
+ * @type: type of the event (EV_KEY, EV_REL, etc...)
+ * @code: event code
+ *
+ * In addition to setting up corresponding bit in appropriate capability
+ * bitmap the function also adjusts dev->evbit.
+ */
+void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code)
+{
+	switch (type) {
+	case EV_KEY:
+		__set_bit(code, dev->keybit);
+		break;
+
+	case EV_REL:
+		__set_bit(code, dev->relbit);
+		break;
+
+	case EV_ABS:
+		input_alloc_absinfo(dev);
+		if (!dev->absinfo)
+			return;
+
+		__set_bit(code, dev->absbit);
+		break;
+
+	case EV_MSC:
+		__set_bit(code, dev->mscbit);
+		break;
+
+	case EV_SW:
+		__set_bit(code, dev->swbit);
+		break;
+
+	case EV_LED:
+		__set_bit(code, dev->ledbit);
+		break;
+
+	case EV_SND:
+		__set_bit(code, dev->sndbit);
+		break;
+
+	case EV_FF:
+		__set_bit(code, dev->ffbit);
+		break;
+
+	case EV_PWR:
+		/* do nothing */
+		break;
+
+	default:
+		pr_err("input_set_capability: unknown type %u (code %u)\n",
+		       type, code);
+		dump_stack();
+		return;
+	}
+
+	__set_bit(type, dev->evbit);
+}
+EXPORT_SYMBOL(input_set_capability);
+
+static unsigned int input_estimate_events_per_packet(struct input_dev *dev)
+{
+	int mt_slots;
+	int i;
+	unsigned int events;
+
+	if (dev->mt) {
+		mt_slots = dev->mt->num_slots;
+	} else if (test_bit(ABS_MT_TRACKING_ID, dev->absbit)) {
+		mt_slots = dev->absinfo[ABS_MT_TRACKING_ID].maximum -
+			   dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1,
+		mt_slots = clamp(mt_slots, 2, 32);
+	} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
+		mt_slots = 2;
+	} else {
+		mt_slots = 0;
+	}
+
+	events = mt_slots + 1; /* count SYN_MT_REPORT and SYN_REPORT */
+
+	if (test_bit(EV_ABS, dev->evbit)) {
+		for (i = 0; i < ABS_CNT; i++) {
+			if (test_bit(i, dev->absbit)) {
+				if (input_is_mt_axis(i))
+					events += mt_slots;
+				else
+					events++;
+			}
+		}
+	}
+
+	if (test_bit(EV_REL, dev->evbit)) {
+		for (i = 0; i < REL_CNT; i++)
+			if (test_bit(i, dev->relbit))
+				events++;
+	}
+
+	/* Make room for KEY and MSC events */
+	events += 7;
+
+	return events;
+}
+
+#define INPUT_CLEANSE_BITMASK(dev, type, bits)				\
+	do {								\
+		if (!test_bit(EV_##type, dev->evbit))			\
+			memset(dev->bits##bit, 0,			\
+				sizeof(dev->bits##bit));		\
+	} while (0)
+
+static void input_cleanse_bitmasks(struct input_dev *dev)
+{
+	INPUT_CLEANSE_BITMASK(dev, KEY, key);
+	INPUT_CLEANSE_BITMASK(dev, REL, rel);
+	INPUT_CLEANSE_BITMASK(dev, ABS, abs);
+	INPUT_CLEANSE_BITMASK(dev, MSC, msc);
+	INPUT_CLEANSE_BITMASK(dev, LED, led);
+	INPUT_CLEANSE_BITMASK(dev, SND, snd);
+	INPUT_CLEANSE_BITMASK(dev, FF, ff);
+	INPUT_CLEANSE_BITMASK(dev, SW, sw);
+}
+
+static void __input_unregister_device(struct input_dev *dev)
+{
+	struct input_handle *handle, *next;
+
+	input_disconnect_device(dev);
+
+	mutex_lock(&input_mutex);
+
+	list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
+		handle->handler->disconnect(handle);
+	WARN_ON(!list_empty(&dev->h_list));
+
+	del_timer_sync(&dev->timer);
+	list_del_init(&dev->node);
+
+	input_wakeup_procfs_readers();
+
+	mutex_unlock(&input_mutex);
+
+	device_del(&dev->dev);
+}
+
+static void devm_input_device_unregister(struct device *dev, void *res)
+{
+	struct input_devres *devres = res;
+	struct input_dev *input = devres->input;
+
+	dev_dbg(dev, "%s: unregistering device %s\n",
+		__func__, dev_name(&input->dev));
+	__input_unregister_device(input);
+}
+
+/**
+ * input_register_device - register device with input core
+ * @dev: device to be registered
+ *
+ * This function registers device with input core. The device must be
+ * allocated with input_allocate_device() and all it's capabilities
+ * set up before registering.
+ * If function fails the device must be freed with input_free_device().
+ * Once device has been successfully registered it can be unregistered
+ * with input_unregister_device(); input_free_device() should not be
+ * called in this case.
+ *
+ * Note that this function is also used to register managed input devices
+ * (ones allocated with devm_input_allocate_device()). Such managed input
+ * devices need not be explicitly unregistered or freed, their tear down
+ * is controlled by the devres infrastructure. It is also worth noting
+ * that tear down of managed input devices is internally a 2-step process:
+ * registered managed input device is first unregistered, but stays in
+ * memory and can still handle input_event() calls (although events will
+ * not be delivered anywhere). The freeing of managed input device will
+ * happen later, when devres stack is unwound to the point where device
+ * allocation was made.
+ */
+int input_register_device(struct input_dev *dev)
+{
+	struct input_devres *devres = NULL;
+	struct input_handler *handler;
+	unsigned int packet_size;
+	const char *path;
+	int error;
+
+	if (dev->devres_managed) {
+		devres = devres_alloc(devm_input_device_unregister,
+				      sizeof(struct input_devres), GFP_KERNEL);
+		if (!devres)
+			return -ENOMEM;
+
+		devres->input = dev;
+	}
+
+	/* Every input device generates EV_SYN/SYN_REPORT events. */
+	__set_bit(EV_SYN, dev->evbit);
+
+	/* KEY_RESERVED is not supposed to be transmitted to userspace. */
+	__clear_bit(KEY_RESERVED, dev->keybit);
+
+	/* Make sure that bitmasks not mentioned in dev->evbit are clean. */
+	input_cleanse_bitmasks(dev);
+
+	packet_size = input_estimate_events_per_packet(dev);
+	if (dev->hint_events_per_packet < packet_size)
+		dev->hint_events_per_packet = packet_size;
+
+	dev->max_vals = dev->hint_events_per_packet + 2;
+	dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
+	if (!dev->vals) {
+		error = -ENOMEM;
+		goto err_devres_free;
+	}
+
+	/*
+	 * If delay and period are pre-set by the driver, then autorepeating
+	 * is handled by the driver itself and we don't do it in input.c.
+	 */
+	if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
+		dev->timer.data = (long) dev;
+		dev->timer.function = input_repeat_key;
+		dev->rep[REP_DELAY] = 250;
+		dev->rep[REP_PERIOD] = 33;
+	}
+
+	if (!dev->getkeycode)
+		dev->getkeycode = input_default_getkeycode;
+
+	if (!dev->setkeycode)
+		dev->setkeycode = input_default_setkeycode;
+
+	error = device_add(&dev->dev);
+	if (error)
+		goto err_free_vals;
+
+	path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
+	pr_info("%s as %s\n",
+		dev->name ? dev->name : "Unspecified device",
+		path ? path : "N/A");
+	kfree(path);
+
+	error = mutex_lock_interruptible(&input_mutex);
+	if (error)
+		goto err_device_del;
+
+	list_add_tail(&dev->node, &input_dev_list);
+
+	list_for_each_entry(handler, &input_handler_list, node)
+		input_attach_handler(dev, handler);
+
+	input_wakeup_procfs_readers();
+
+	mutex_unlock(&input_mutex);
+
+	if (dev->devres_managed) {
+		dev_dbg(dev->dev.parent, "%s: registering %s with devres.\n",
+			__func__, dev_name(&dev->dev));
+		devres_add(dev->dev.parent, devres);
+	}
+	return 0;
+
+err_device_del:
+	device_del(&dev->dev);
+err_free_vals:
+	kfree(dev->vals);
+	dev->vals = NULL;
+err_devres_free:
+	devres_free(devres);
+	return error;
+}
+EXPORT_SYMBOL(input_register_device);
+
+/**
+ * input_unregister_device - unregister previously registered device
+ * @dev: device to be unregistered
+ *
+ * This function unregisters an input device. Once device is unregistered
+ * the caller should not try to access it as it may get freed at any moment.
+ */
+void input_unregister_device(struct input_dev *dev)
+{
+	if (dev->devres_managed) {
+		WARN_ON(devres_destroy(dev->dev.parent,
+					devm_input_device_unregister,
+					devm_input_device_match,
+					dev));
+		__input_unregister_device(dev);
+		/*
+		 * We do not do input_put_device() here because it will be done
+		 * when 2nd devres fires up.
+		 */
+	} else {
+		__input_unregister_device(dev);
+		input_put_device(dev);
+	}
+}
+EXPORT_SYMBOL(input_unregister_device);
+
+/**
+ * input_register_handler - register a new input handler
+ * @handler: handler to be registered
+ *
+ * This function registers a new input handler (interface) for input
+ * devices in the system and attaches it to all input devices that
+ * are compatible with the handler.
+ */
+int input_register_handler(struct input_handler *handler)
+{
+	struct input_dev *dev;
+	int error;
+
+	error = mutex_lock_interruptible(&input_mutex);
+	if (error)
+		return error;
+
+	INIT_LIST_HEAD(&handler->h_list);
+
+	list_add_tail(&handler->node, &input_handler_list);
+
+	list_for_each_entry(dev, &input_dev_list, node)
+		input_attach_handler(dev, handler);
+
+	input_wakeup_procfs_readers();
+
+	mutex_unlock(&input_mutex);
+	return 0;
+}
+EXPORT_SYMBOL(input_register_handler);
+
+/**
+ * input_unregister_handler - unregisters an input handler
+ * @handler: handler to be unregistered
+ *
+ * This function disconnects a handler from its input devices and
+ * removes it from lists of known handlers.
+ */
+void input_unregister_handler(struct input_handler *handler)
+{
+	struct input_handle *handle, *next;
+
+	mutex_lock(&input_mutex);
+
+	list_for_each_entry_safe(handle, next, &handler->h_list, h_node)
+		handler->disconnect(handle);
+	WARN_ON(!list_empty(&handler->h_list));
+
+	list_del_init(&handler->node);
+
+	input_wakeup_procfs_readers();
+
+	mutex_unlock(&input_mutex);
+}
+EXPORT_SYMBOL(input_unregister_handler);
+
+/**
+ * input_handler_for_each_handle - handle iterator
+ * @handler: input handler to iterate
+ * @data: data for the callback
+ * @fn: function to be called for each handle
+ *
+ * Iterate over @bus's list of devices, and call @fn for each, passing
+ * it @data and stop when @fn returns a non-zero value. The function is
+ * using RCU to traverse the list and therefore may be usind in atonic
+ * contexts. The @fn callback is invoked from RCU critical section and
+ * thus must not sleep.
+ */
+int input_handler_for_each_handle(struct input_handler *handler, void *data,
+				  int (*fn)(struct input_handle *, void *))
+{
+	struct input_handle *handle;
+	int retval = 0;
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(handle, &handler->h_list, h_node) {
+		retval = fn(handle, data);
+		if (retval)
+			break;
+	}
+
+	rcu_read_unlock();
+
+	return retval;
+}
+EXPORT_SYMBOL(input_handler_for_each_handle);
+
+/**
+ * input_register_handle - register a new input handle
+ * @handle: handle to register
+ *
+ * This function puts a new input handle onto device's
+ * and handler's lists so that events can flow through
+ * it once it is opened using input_open_device().
+ *
+ * This function is supposed to be called from handler's
+ * connect() method.
+ */
+int input_register_handle(struct input_handle *handle)
+{
+	struct input_handler *handler = handle->handler;
+	struct input_dev *dev = handle->dev;
+	int error;
+
+	/*
+	 * We take dev->mutex here to prevent race with
+	 * input_release_device().
+	 */
+	error = mutex_lock_interruptible(&dev->mutex);
+	if (error)
+		return error;
+
+	/*
+	 * Filters go to the head of the list, normal handlers
+	 * to the tail.
+	 */
+	if (handler->filter)
+		list_add_rcu(&handle->d_node, &dev->h_list);
+	else
+		list_add_tail_rcu(&handle->d_node, &dev->h_list);
+
+	mutex_unlock(&dev->mutex);
+
+	/*
+	 * Since we are supposed to be called from ->connect()
+	 * which is mutually exclusive with ->disconnect()
+	 * we can't be racing with input_unregister_handle()
+	 * and so separate lock is not needed here.
+	 */
+	list_add_tail_rcu(&handle->h_node, &handler->h_list);
+
+	if (handler->start)
+		handler->start(handle);
+
+	return 0;
+}
+EXPORT_SYMBOL(input_register_handle);
+
+/**
+ * input_unregister_handle - unregister an input handle
+ * @handle: handle to unregister
+ *
+ * This function removes input handle from device's
+ * and handler's lists.
+ *
+ * This function is supposed to be called from handler's
+ * disconnect() method.
+ */
+void input_unregister_handle(struct input_handle *handle)
+{
+	struct input_dev *dev = handle->dev;
+
+	list_del_rcu(&handle->h_node);
+
+	/*
+	 * Take dev->mutex to prevent race with input_release_device().
+	 */
+	mutex_lock(&dev->mutex);
+	list_del_rcu(&handle->d_node);
+	mutex_unlock(&dev->mutex);
+
+	synchronize_rcu();
+}
+EXPORT_SYMBOL(input_unregister_handle);
+
+/**
+ * input_get_new_minor - allocates a new input minor number
+ * @legacy_base: beginning or the legacy range to be searched
+ * @legacy_num: size of legacy range
+ * @allow_dynamic: whether we can also take ID from the dynamic range
+ *
+ * This function allocates a new device minor for from input major namespace.
+ * Caller can request legacy minor by specifying @legacy_base and @legacy_num
+ * parameters and whether ID can be allocated from dynamic range if there are
+ * no free IDs in legacy range.
+ */
+int input_get_new_minor(int legacy_base, unsigned int legacy_num,
+			bool allow_dynamic)
+{
+	/*
+	 * This function should be called from input handler's ->connect()
+	 * methods, which are serialized with input_mutex, so no additional
+	 * locking is needed here.
+	 */
+	if (legacy_base >= 0) {
+		int minor = ida_simple_get(&input_ida,
+					   legacy_base,
+					   legacy_base + legacy_num,
+					   GFP_KERNEL);
+		if (minor >= 0 || !allow_dynamic)
+			return minor;
+	}
+
+	return ida_simple_get(&input_ida,
+			      INPUT_FIRST_DYNAMIC_DEV, INPUT_MAX_CHAR_DEVICES,
+			      GFP_KERNEL);
+}
+EXPORT_SYMBOL(input_get_new_minor);
+
+/**
+ * input_free_minor - release previously allocated minor
+ * @minor: minor to be released
+ *
+ * This function releases previously allocated input minor so that it can be
+ * reused later.
+ */
+void input_free_minor(unsigned int minor)
+{
+	ida_simple_remove(&input_ida, minor);
+}
+EXPORT_SYMBOL(input_free_minor);
+
+static int __init input_init(void)
+{
+	int err;
+
+	err = class_register(&input_class);
+	if (err) {
+		pr_err("unable to register input_dev class\n");
+		return err;
+	}
+
+	err = input_proc_init();
+	if (err)
+		goto fail1;
+
+	err = register_chrdev_region(MKDEV(INPUT_MAJOR, 0),
+				     INPUT_MAX_CHAR_DEVICES, "input");
+	if (err) {
+		pr_err("unable to register char major %d", INPUT_MAJOR);
+		goto fail2;
+	}
+
+	return 0;
+
+ fail2:	input_proc_exit();
+ fail1:	class_unregister(&input_class);
+	return err;
+}
+
+static void __exit input_exit(void)
+{
+	input_proc_exit();
+	unregister_chrdev_region(MKDEV(INPUT_MAJOR, 0),
+				 INPUT_MAX_CHAR_DEVICES);
+	class_unregister(&input_class);
+}
+
+subsys_initcall(input_init);
+module_exit(input_exit);