[linux.git] / drivers / input / ff-core.c

/*
 *  Force feedback support for Linux input subsystem
 *
 *  Copyright (c) 2006 Anssi Hannula <[email protected]>
 *  Copyright (c) 2006 Dmitry Torokhov <[email protected]>
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/* #define DEBUG */

#include <linux/input.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/slab.h>

/*
 * Check that the effect_id is a valid effect and whether the user
 * is the owner
 */
static int check_effect_access(struct ff_device *ff, int effect_id,
				struct file *file)
{
	if (effect_id < 0 || effect_id >= ff->max_effects ||
	    !ff->effect_owners[effect_id])
		return -EINVAL;

	if (file && ff->effect_owners[effect_id] != file)
		return -EACCES;

	return 0;
}

/*
 * Checks whether 2 effects can be combined together
 */
static inline int check_effects_compatible(struct ff_effect *e1,
					   struct ff_effect *e2)
{
	return e1->type == e2->type &&
	       (e1->type != FF_PERIODIC ||
		e1->u.periodic.waveform == e2->u.periodic.waveform);
}

/*
 * Convert an effect into compatible one
 */
static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
{
	int magnitude;

	switch (effect->type) {
	case FF_RUMBLE:
		if (!test_bit(FF_PERIODIC, ff->ffbit))
			return -EINVAL;

		/*
		 * calculate magnitude of sine wave as average of rumble's
		 * 2/3 of strong magnitude and 1/3 of weak magnitude
		 */
		magnitude = effect->u.rumble.strong_magnitude / 3 +
			    effect->u.rumble.weak_magnitude / 6;

		effect->type = FF_PERIODIC;
		effect->u.periodic.waveform = FF_SINE;
		effect->u.periodic.period = 50;
		effect->u.periodic.magnitude = max(magnitude, 0x7fff);
		effect->u.periodic.offset = 0;
		effect->u.periodic.phase = 0;
		effect->u.periodic.envelope.attack_length = 0;
		effect->u.periodic.envelope.attack_level = 0;
		effect->u.periodic.envelope.fade_length = 0;
		effect->u.periodic.envelope.fade_level = 0;

		return 0;

	default:
		/* Let driver handle conversion */
		return 0;
	}
}

/**
 * input_ff_upload() - upload effect into force-feedback device
 * @dev: input device
 * @effect: effect to be uploaded
 * @file: owner of the effect
 */
int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
		    struct file *file)
{
	struct ff_device *ff = dev->ff;
	struct ff_effect *old;
	int ret = 0;
	int id;

	if (!test_bit(EV_FF, dev->evbit))
		return -ENOSYS;

	if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
	    !test_bit(effect->type, dev->ffbit)) {
		dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n");
		return -EINVAL;
	}

	if (effect->type == FF_PERIODIC &&
	    (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
	     effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
	     !test_bit(effect->u.periodic.waveform, dev->ffbit))) {
		dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n");
		return -EINVAL;
	}

	if (!test_bit(effect->type, ff->ffbit)) {
		ret = compat_effect(ff, effect);
		if (ret)
			return ret;
	}

	mutex_lock(&ff->mutex);

	if (effect->id == -1) {
		for (id = 0; id < ff->max_effects; id++)
			if (!ff->effect_owners[id])
				break;

		if (id >= ff->max_effects) {
			ret = -ENOSPC;
			goto out;
		}

		effect->id = id;
		old = NULL;

	} else {
		id = effect->id;

		ret = check_effect_access(ff, id, file);
		if (ret)
			goto out;

		old = &ff->effects[id];

		if (!check_effects_compatible(effect, old)) {
			ret = -EINVAL;
			goto out;
		}
	}

	ret = ff->upload(dev, effect, old);
	if (ret)
		goto out;

	spin_lock_irq(&dev->event_lock);
	ff->effects[id] = *effect;
	ff->effect_owners[id] = file;
	spin_unlock_irq(&dev->event_lock);

 out:
	mutex_unlock(&ff->mutex);
	return ret;
}
EXPORT_SYMBOL_GPL(input_ff_upload);

/*
 * Erases the effect if the requester is also the effect owner. The mutex
 * should already be locked before calling this function.
 */
static int erase_effect(struct input_dev *dev, int effect_id,
			struct file *file)
{
	struct ff_device *ff = dev->ff;
	int error;

	error = check_effect_access(ff, effect_id, file);
	if (error)
		return error;

	spin_lock_irq(&dev->event_lock);
	ff->playback(dev, effect_id, 0);
	ff->effect_owners[effect_id] = NULL;
	spin_unlock_irq(&dev->event_lock);

	if (ff->erase) {
		error = ff->erase(dev, effect_id);
		if (error) {
			spin_lock_irq(&dev->event_lock);
			ff->effect_owners[effect_id] = file;
			spin_unlock_irq(&dev->event_lock);

			return error;
		}
	}

	return 0;
}

/**
 * input_ff_erase - erase a force-feedback effect from device
 * @dev: input device to erase effect from
 * @effect_id: id of the effect to be erased
 * @file: purported owner of the request
 *
 * This function erases a force-feedback effect from specified device.
 * The effect will only be erased if it was uploaded through the same
 * file handle that is requesting erase.
 */
int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
{
	struct ff_device *ff = dev->ff;
	int ret;

	if (!test_bit(EV_FF, dev->evbit))
		return -ENOSYS;

	mutex_lock(&ff->mutex);
	ret = erase_effect(dev, effect_id, file);
	mutex_unlock(&ff->mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(input_ff_erase);

/*
 * flush_effects - erase all effects owned by a file handle
 */
static int flush_effects(struct input_dev *dev, struct file *file)
{
	struct ff_device *ff = dev->ff;
	int i;

	dev_dbg(&dev->dev, "flushing now\n");

	mutex_lock(&ff->mutex);

	for (i = 0; i < ff->max_effects; i++)
		erase_effect(dev, i, file);

	mutex_unlock(&ff->mutex);

	return 0;
}

/**
 * input_ff_event() - generic handler for force-feedback events
 * @dev: input device to send the effect to
 * @type: event type (anything but EV_FF is ignored)
 * @code: event code
 * @value: event value
 */
int input_ff_event(struct input_dev *dev, unsigned int type,
		   unsigned int code, int value)
{
	struct ff_device *ff = dev->ff;

	if (type != EV_FF)
		return 0;

	switch (code) {
	case FF_GAIN:
		if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffffU)
			break;

		ff->set_gain(dev, value);
		break;

	case FF_AUTOCENTER:
		if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffffU)
			break;

		ff->set_autocenter(dev, value);
		break;

	default:
		if (check_effect_access(ff, code, NULL) == 0)
			ff->playback(dev, code, value);
		break;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(input_ff_event);

/**
 * input_ff_create() - create force-feedback device
 * @dev: input device supporting force-feedback
 * @max_effects: maximum number of effects supported by the device
 *
 * This function allocates all necessary memory for a force feedback
 * portion of an input device and installs all default handlers.
 * @dev->ffbit should be already set up before calling this function.
 * Once ff device is created you need to setup its upload, erase,
 * playback and other handlers before registering input device
 */
int input_ff_create(struct input_dev *dev, unsigned int max_effects)
{
	struct ff_device *ff;
	size_t ff_dev_size;
	int i;

	if (!max_effects) {
		dev_err(&dev->dev, "cannot allocate device without any effects\n");
		return -EINVAL;
	}

	if (max_effects > FF_MAX_EFFECTS) {
		dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n");
		return -EINVAL;
	}

	ff_dev_size = sizeof(struct ff_device) +
				max_effects * sizeof(struct file *);
	if (ff_dev_size < max_effects) /* overflow */
		return -EINVAL;

	ff = kzalloc(ff_dev_size, GFP_KERNEL);
	if (!ff)
		return -ENOMEM;

	ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
			      GFP_KERNEL);
	if (!ff->effects) {
		kfree(ff);
		return -ENOMEM;
	}

	ff->max_effects = max_effects;
	mutex_init(&ff->mutex);

	dev->ff = ff;
	dev->flush = flush_effects;
	dev->event = input_ff_event;
	__set_bit(EV_FF, dev->evbit);

	/* Copy "true" bits into ff device bitmap */
	for_each_set_bit(i, dev->ffbit, FF_CNT)
		__set_bit(i, ff->ffbit);

	/* we can emulate RUMBLE with periodic effects */
	if (test_bit(FF_PERIODIC, ff->ffbit))
		__set_bit(FF_RUMBLE, dev->ffbit);

	return 0;
}
EXPORT_SYMBOL_GPL(input_ff_create);

/**
 * input_ff_destroy() - frees force feedback portion of input device
 * @dev: input device supporting force feedback
 *
 * This function is only needed in error path as input core will
 * automatically free force feedback structures when device is
 * destroyed.
 */
void input_ff_destroy(struct input_dev *dev)
{
	struct ff_device *ff = dev->ff;

	__clear_bit(EV_FF, dev->evbit);
	if (ff) {
		if (ff->destroy)
			ff->destroy(ff);
		kfree(ff->private);
		kfree(ff->effects);
		kfree(ff);
		dev->ff = NULL;
	}
}
EXPORT_SYMBOL_GPL(input_ff_destroy);
Commit	Line	Data
509ca1a9 AH	1	/*
	2	* Force feedback support for Linux input subsystem
	3	*
	4	* Copyright (c) 2006 Anssi Hannula <[email protected]>
	5	* Copyright (c) 2006 Dmitry Torokhov <[email protected]>
	6	*/
	7
	8	/*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation; either version 2 of the License, or
	12	* (at your option) any later version.
	13	*
	14	* This program is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	* GNU General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License
	20	* along with this program; if not, write to the Free Software
	21	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	22	*/
	23
	24	/* #define DEBUG */
	25
509ca1a9 AH	26	#include <linux/input.h>
	27	#include <linux/module.h>
	28	#include <linux/mutex.h>
83680cdb	29	#include <linux/sched.h>
5a0e3ad6	30	#include <linux/slab.h>
509ca1a9 AH	31
	32	/*
	33	* Check that the effect_id is a valid effect and whether the user
	34	* is the owner
	35	*/
	36	static int check_effect_access(struct ff_device *ff, int effect_id,
	37	struct file *file)
	38	{
	39	if (effect_id < 0 \|\| effect_id >= ff->max_effects \|\|
	40	!ff->effect_owners[effect_id])
	41	return -EINVAL;
	42
	43	if (file && ff->effect_owners[effect_id] != file)
	44	return -EACCES;
	45
	46	return 0;
	47	}
	48
	49	/*
	50	* Checks whether 2 effects can be combined together
	51	*/
	52	static inline int check_effects_compatible(struct ff_effect *e1,
	53	struct ff_effect *e2)
	54	{
	55	return e1->type == e2->type &&
	56	(e1->type != FF_PERIODIC \|\|
	57	e1->u.periodic.waveform == e2->u.periodic.waveform);
	58	}
	59
	60	/*
	61	* Convert an effect into compatible one
	62	*/
	63	static int compat_effect(struct ff_device ff, struct ff_effect effect)
	64	{
	65	int magnitude;
	66
	67	switch (effect->type) {
	68	case FF_RUMBLE:
	69	if (!test_bit(FF_PERIODIC, ff->ffbit))
	70	return -EINVAL;
	71
	72	/*
8a4dda79	73	* calculate magnitude of sine wave as average of rumble's
509ca1a9 AH	74	* 2/3 of strong magnitude and 1/3 of weak magnitude
	75	*/
	76	magnitude = effect->u.rumble.strong_magnitude / 3 +
	77	effect->u.rumble.weak_magnitude / 6;
	78
	79	effect->type = FF_PERIODIC;
	80	effect->u.periodic.waveform = FF_SINE;
	81	effect->u.periodic.period = 50;
	82	effect->u.periodic.magnitude = max(magnitude, 0x7fff);
	83	effect->u.periodic.offset = 0;
	84	effect->u.periodic.phase = 0;
	85	effect->u.periodic.envelope.attack_length = 0;
	86	effect->u.periodic.envelope.attack_level = 0;
	87	effect->u.periodic.envelope.fade_length = 0;
	88	effect->u.periodic.envelope.fade_level = 0;
	89
	90	return 0;
	91
	92	default:
	93	/* Let driver handle conversion */
	94	return 0;
	95	}
	96	}
	97
	98	/**
	99	* input_ff_upload() - upload effect into force-feedback device
	100	* @dev: input device
	101	* @effect: effect to be uploaded
	102	* @file: owner of the effect
	103	*/
	104	int input_ff_upload(struct input_dev dev, struct ff_effect effect,
	105	struct file *file)
	106	{
	107	struct ff_device *ff = dev->ff;
	108	struct ff_effect *old;
	109	int ret = 0;
	110	int id;
	111
	112	if (!test_bit(EV_FF, dev->evbit))
	113	return -ENOSYS;
	114
	115	if (effect->type < FF_EFFECT_MIN \|\| effect->type > FF_EFFECT_MAX \|\|
	116	!test_bit(effect->type, dev->ffbit)) {
2afebafd	117	dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n");
509ca1a9 AH	118	return -EINVAL;
	119	}
	120
	121	if (effect->type == FF_PERIODIC &&
	122	(effect->u.periodic.waveform < FF_WAVEFORM_MIN \|\|
	123	effect->u.periodic.waveform > FF_WAVEFORM_MAX \|\|
	124	!test_bit(effect->u.periodic.waveform, dev->ffbit))) {
2afebafd	125	dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n");
509ca1a9 AH	126	return -EINVAL;
	127	}
	128
	129	if (!test_bit(effect->type, ff->ffbit)) {
	130	ret = compat_effect(ff, effect);
	131	if (ret)
	132	return ret;
	133	}
	134
	135	mutex_lock(&ff->mutex);
	136
	137	if (effect->id == -1) {
	138	for (id = 0; id < ff->max_effects; id++)
41091ad0 BC	139	if (!ff->effect_owners[id])
41091ad0 BC	140	break;
509ca1a9 AH	141
	142	if (id >= ff->max_effects) {
	143	ret = -ENOSPC;
	144	goto out;
	145	}
	146
	147	effect->id = id;
	148	old = NULL;
	149
	150	} else {
	151	id = effect->id;
	152
	153	ret = check_effect_access(ff, id, file);
	154	if (ret)
	155	goto out;
	156
	157	old = &ff->effects[id];
	158
	159	if (!check_effects_compatible(effect, old)) {
	160	ret = -EINVAL;
	161	goto out;
	162	}
	163	}
	164
	165	ret = ff->upload(dev, effect, old);
	166	if (ret)
	167	goto out;
	168
656acd2b	169	spin_lock_irq(&dev->event_lock);
509ca1a9 AH	170	ff->effects[id] = *effect;
509ca1a9 AH	171	ff->effect_owners[id] = file;
656acd2b	172	spin_unlock_irq(&dev->event_lock);
509ca1a9 AH	173
	174	out:
	175	mutex_unlock(&ff->mutex);
	176	return ret;
	177	}
	178	EXPORT_SYMBOL_GPL(input_ff_upload);
	179
	180	/*
	181	* Erases the effect if the requester is also the effect owner. The mutex
	182	* should already be locked before calling this function.
	183	*/
	184	static int erase_effect(struct input_dev *dev, int effect_id,
	185	struct file *file)
	186	{
	187	struct ff_device *ff = dev->ff;
	188	int error;
	189
	190	error = check_effect_access(ff, effect_id, file);
	191	if (error)
	192	return error;
	193
656acd2b	194	spin_lock_irq(&dev->event_lock);
509ca1a9	195	ff->playback(dev, effect_id, 0);
656acd2b DT	196	ff->effect_owners[effect_id] = NULL;
656acd2b DT	197	spin_unlock_irq(&dev->event_lock);
509ca1a9 AH	198
	199	if (ff->erase) {
	200	error = ff->erase(dev, effect_id);
656acd2b DT	201	if (error) {
	202	spin_lock_irq(&dev->event_lock);
	203	ff->effect_owners[effect_id] = file;
	204	spin_unlock_irq(&dev->event_lock);
	205
509ca1a9	206	return error;
656acd2b	207	}
509ca1a9 AH	208	}
509ca1a9 AH	209
509ca1a9 AH	210	return 0;
	211	}
	212
	213	/**
e4477d2d	214	* input_ff_erase - erase a force-feedback effect from device
509ca1a9	215	* @dev: input device to erase effect from
4e3e4629	216	* @effect_id: id of the effect to be erased
509ca1a9 AH	217	* @file: purported owner of the request
	218	*
	219	* This function erases a force-feedback effect from specified device.
	220	* The effect will only be erased if it was uploaded through the same
	221	* file handle that is requesting erase.
	222	*/
	223	int input_ff_erase(struct input_dev dev, int effect_id, struct file file)
	224	{
	225	struct ff_device *ff = dev->ff;
	226	int ret;
	227
	228	if (!test_bit(EV_FF, dev->evbit))
	229	return -ENOSYS;
	230
	231	mutex_lock(&ff->mutex);
	232	ret = erase_effect(dev, effect_id, file);
	233	mutex_unlock(&ff->mutex);
	234
	235	return ret;
	236	}
	237	EXPORT_SYMBOL_GPL(input_ff_erase);
	238
	239	/*
	240	* flush_effects - erase all effects owned by a file handle
	241	*/
	242	static int flush_effects(struct input_dev dev, struct file file)
	243	{
	244	struct ff_device *ff = dev->ff;
	245	int i;
	246
2afebafd	247	dev_dbg(&dev->dev, "flushing now\n");
509ca1a9 AH	248
	249	mutex_lock(&ff->mutex);
	250
	251	for (i = 0; i < ff->max_effects; i++)
	252	erase_effect(dev, i, file);
	253
	254	mutex_unlock(&ff->mutex);
	255
	256	return 0;
	257	}
	258
	259	/**
	260	* input_ff_event() - generic handler for force-feedback events
	261	* @dev: input device to send the effect to
	262	* @type: event type (anything but EV_FF is ignored)
	263	* @code: event code
	264	* @value: event value
	265	*/
	266	int input_ff_event(struct input_dev *dev, unsigned int type,
	267	unsigned int code, int value)
	268	{
	269	struct ff_device *ff = dev->ff;
	270
	271	if (type != EV_FF)
	272	return 0;
	273
509ca1a9 AH	274	switch (code) {
509ca1a9 AH	275	case FF_GAIN:
379d7cfa	276	if (!test_bit(FF_GAIN, dev->ffbit) \|\| value > 0xffffU)
509ca1a9 AH	277	break;
	278
	279	ff->set_gain(dev, value);
	280	break;
	281
	282	case FF_AUTOCENTER:
379d7cfa	283	if (!test_bit(FF_AUTOCENTER, dev->ffbit) \|\| value > 0xffffU)
509ca1a9 AH	284	break;
	285
	286	ff->set_autocenter(dev, value);
	287	break;
	288
	289	default:
dec3eb01 DT	290	if (check_effect_access(ff, code, NULL) == 0)
dec3eb01 DT	291	ff->playback(dev, code, value);
509ca1a9 AH	292	break;
	293	}
	294
509ca1a9 AH	295	return 0;
	296	}
	297	EXPORT_SYMBOL_GPL(input_ff_event);
	298
	299	/**
	300	* input_ff_create() - create force-feedback device
	301	* @dev: input device supporting force-feedback
	302	* @max_effects: maximum number of effects supported by the device
	303	*
	304	* This function allocates all necessary memory for a force feedback
	305	* portion of an input device and installs all default handlers.
	306	* @dev->ffbit should be already set up before calling this function.
	307	* Once ff device is created you need to setup its upload, erase,
	308	* playback and other handlers before registering input device
	309	*/
05be8b81	310	int input_ff_create(struct input_dev *dev, unsigned int max_effects)
509ca1a9 AH	311	{
509ca1a9 AH	312	struct ff_device *ff;
05be8b81	313	size_t ff_dev_size;
509ca1a9 AH	314	int i;
	315
	316	if (!max_effects) {
2afebafd	317	dev_err(&dev->dev, "cannot allocate device without any effects\n");
509ca1a9 AH	318	return -EINVAL;
	319	}
	320
33b96d93 EV	321	if (max_effects > FF_MAX_EFFECTS) {
	322	dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n");
	323	return -EINVAL;
	324	}
	325
05be8b81 DC	326	ff_dev_size = sizeof(struct ff_device) +
	327	max_effects * sizeof(struct file *);
	328	if (ff_dev_size < max_effects) /* overflow */
	329	return -EINVAL;
	330
	331	ff = kzalloc(ff_dev_size, GFP_KERNEL);
509ca1a9 AH	332	if (!ff)
	333	return -ENOMEM;
	334
	335	ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
	336	GFP_KERNEL);
	337	if (!ff->effects) {
	338	kfree(ff);
	339	return -ENOMEM;
	340	}
	341
	342	ff->max_effects = max_effects;
	343	mutex_init(&ff->mutex);
	344
	345	dev->ff = ff;
	346	dev->flush = flush_effects;
	347	dev->event = input_ff_event;
bf3204cb	348	__set_bit(EV_FF, dev->evbit);
509ca1a9 AH	349
509ca1a9 AH	350	/* Copy "true" bits into ff device bitmap */
948cea14 AG	351	for_each_set_bit(i, dev->ffbit, FF_CNT)
948cea14 AG	352	__set_bit(i, ff->ffbit);
509ca1a9 AH	353
	354	/* we can emulate RUMBLE with periodic effects */
	355	if (test_bit(FF_PERIODIC, ff->ffbit))
bf3204cb	356	__set_bit(FF_RUMBLE, dev->ffbit);
509ca1a9 AH	357
	358	return 0;
	359	}
	360	EXPORT_SYMBOL_GPL(input_ff_create);
	361
	362	/**
721a730e	363	* input_ff_destroy() - frees force feedback portion of input device
e4477d2d	364	* @dev: input device supporting force feedback
509ca1a9 AH	365	*
	366	* This function is only needed in error path as input core will
	367	* automatically free force feedback structures when device is
	368	* destroyed.
	369	*/
	370	void input_ff_destroy(struct input_dev *dev)
	371	{
bf3204cb DT	372	struct ff_device *ff = dev->ff;
	373
	374	__clear_bit(EV_FF, dev->evbit);
	375	if (ff) {
	376	if (ff->destroy)
	377	ff->destroy(ff);
	378	kfree(ff->private);
6a47081c	379	kfree(ff->effects);
bf3204cb	380	kfree(ff);
509ca1a9 AH	381	dev->ff = NULL;
	382	}
	383	}
	384	EXPORT_SYMBOL_GPL(input_ff_destroy);