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

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Force feedback support for memoryless devices
 *
 *  Copyright (c) 2006 Anssi Hannula <[email protected]>
 *  Copyright (c) 2006 Dmitry Torokhov <[email protected]>
 */

/*
 */

/* #define DEBUG */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/slab.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/jiffies.h>
#include <linux/fixp-arith.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Anssi Hannula <[email protected]>");
MODULE_DESCRIPTION("Force feedback support for memoryless devices");

/* Number of effects handled with memoryless devices */
#define FF_MEMLESS_EFFECTS	16

/* Envelope update interval in ms */
#define FF_ENVELOPE_INTERVAL	50

#define FF_EFFECT_STARTED	0
#define FF_EFFECT_PLAYING	1
#define FF_EFFECT_ABORTING	2

struct ml_effect_state {
	struct ff_effect *effect;
	unsigned long flags;	/* effect state (STARTED, PLAYING, etc) */
	int count;		/* loop count of the effect */
	unsigned long play_at;	/* start time */
	unsigned long stop_at;	/* stop time */
	unsigned long adj_at;	/* last time the effect was sent */
};

struct ml_device {
	void *private;
	struct ml_effect_state states[FF_MEMLESS_EFFECTS];
	int gain;
	struct timer_list timer;
	struct input_dev *dev;

	int (*play_effect)(struct input_dev *dev, void *data,
			   struct ff_effect *effect);
};

static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
{
	static const struct ff_envelope empty_envelope;

	switch (effect->type) {
	case FF_PERIODIC:
		return &effect->u.periodic.envelope;

	case FF_CONSTANT:
		return &effect->u.constant.envelope;

	default:
		return &empty_envelope;
	}
}

/*
 * Check for the next time envelope requires an update on memoryless devices
 */
static unsigned long calculate_next_time(struct ml_effect_state *state)
{
	const struct ff_envelope *envelope = get_envelope(state->effect);
	unsigned long attack_stop, fade_start, next_fade;

	if (envelope->attack_length) {
		attack_stop = state->play_at +
			msecs_to_jiffies(envelope->attack_length);
		if (time_before(state->adj_at, attack_stop))
			return state->adj_at +
					msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
	}

	if (state->effect->replay.length) {
		if (envelope->fade_length) {
			/* check when fading should start */
			fade_start = state->stop_at -
					msecs_to_jiffies(envelope->fade_length);

			if (time_before(state->adj_at, fade_start))
				return fade_start;

			/* already fading, advance to next checkpoint */
			next_fade = state->adj_at +
					msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
			if (time_before(next_fade, state->stop_at))
				return next_fade;
		}

		return state->stop_at;
	}

	return state->play_at;
}

static void ml_schedule_timer(struct ml_device *ml)
{
	struct ml_effect_state *state;
	unsigned long now = jiffies;
	unsigned long earliest = 0;
	unsigned long next_at;
	int events = 0;
	int i;

	pr_debug("calculating next timer\n");

	for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {

		state = &ml->states[i];

		if (!test_bit(FF_EFFECT_STARTED, &state->flags))
			continue;

		if (test_bit(FF_EFFECT_PLAYING, &state->flags))
			next_at = calculate_next_time(state);
		else
			next_at = state->play_at;

		if (time_before_eq(now, next_at) &&
		    (++events == 1 || time_before(next_at, earliest)))
			earliest = next_at;
	}

	if (!events) {
		pr_debug("no actions\n");
		del_timer(&ml->timer);
	} else {
		pr_debug("timer set\n");
		mod_timer(&ml->timer, earliest);
	}
}

/*
 * Apply an envelope to a value
 */
static int apply_envelope(struct ml_effect_state *state, int value,
			  struct ff_envelope *envelope)
{
	struct ff_effect *effect = state->effect;
	unsigned long now = jiffies;
	int time_from_level;
	int time_of_envelope;
	int envelope_level;
	int difference;

	if (envelope->attack_length &&
	    time_before(now,
			state->play_at + msecs_to_jiffies(envelope->attack_length))) {
		pr_debug("value = 0x%x, attack_level = 0x%x\n",
			 value, envelope->attack_level);
		time_from_level = jiffies_to_msecs(now - state->play_at);
		time_of_envelope = envelope->attack_length;
		envelope_level = min_t(u16, envelope->attack_level, 0x7fff);

	} else if (envelope->fade_length && effect->replay.length &&
		   time_after(now,
			      state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
		   time_before(now, state->stop_at)) {
		time_from_level = jiffies_to_msecs(state->stop_at - now);
		time_of_envelope = envelope->fade_length;
		envelope_level = min_t(u16, envelope->fade_level, 0x7fff);
	} else
		return value;

	difference = abs(value) - envelope_level;

	pr_debug("difference = %d\n", difference);
	pr_debug("time_from_level = 0x%x\n", time_from_level);
	pr_debug("time_of_envelope = 0x%x\n", time_of_envelope);

	difference = difference * time_from_level / time_of_envelope;

	pr_debug("difference = %d\n", difference);

	return value < 0 ?
		-(difference + envelope_level) : (difference + envelope_level);
}

/*
 * Return the type the effect has to be converted into (memless devices)
 */
static int get_compatible_type(struct ff_device *ff, int effect_type)
{

	if (test_bit(effect_type, ff->ffbit))
		return effect_type;

	if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
		return FF_RUMBLE;

	pr_err("invalid type in get_compatible_type()\n");

	return 0;
}

/*
 * Only left/right direction should be used (under/over 0x8000) for
 * forward/reverse motor direction (to keep calculation fast & simple).
 */
static u16 ml_calculate_direction(u16 direction, u16 force,
				  u16 new_direction, u16 new_force)
{
	if (!force)
		return new_direction;
	if (!new_force)
		return direction;
	return (((u32)(direction >> 1) * force +
		 (new_direction >> 1) * new_force) /
		(force + new_force)) << 1;
}

#define FRAC_N 8
static inline s16 fixp_new16(s16 a)
{
	return ((s32)a) >> (16 - FRAC_N);
}

static inline s16 fixp_mult(s16 a, s16 b)
{
	a = ((s32)a * 0x100) / 0x7fff;
	return ((s32)(a * b)) >> FRAC_N;
}

/*
 * Combine two effects and apply gain.
 */
static void ml_combine_effects(struct ff_effect *effect,
			       struct ml_effect_state *state,
			       int gain)
{
	struct ff_effect *new = state->effect;
	unsigned int strong, weak, i;
	int x, y;
	s16 level;

	switch (new->type) {
	case FF_CONSTANT:
		i = new->direction * 360 / 0xffff;
		level = fixp_new16(apply_envelope(state,
					new->u.constant.level,
					&new->u.constant.envelope));
		x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff;
		y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff;
		/*
		 * here we abuse ff_ramp to hold x and y of constant force
		 * If in future any driver wants something else than x and y
		 * in s8, this should be changed to something more generic
		 */
		effect->u.ramp.start_level =
			clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
		effect->u.ramp.end_level =
			clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
		break;

	case FF_RUMBLE:
		strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
		weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;

		if (effect->u.rumble.strong_magnitude + strong)
			effect->direction = ml_calculate_direction(
				effect->direction,
				effect->u.rumble.strong_magnitude,
				new->direction, strong);
		else if (effect->u.rumble.weak_magnitude + weak)
			effect->direction = ml_calculate_direction(
				effect->direction,
				effect->u.rumble.weak_magnitude,
				new->direction, weak);
		else
			effect->direction = 0;
		effect->u.rumble.strong_magnitude =
			min(strong + effect->u.rumble.strong_magnitude,
			    0xffffU);
		effect->u.rumble.weak_magnitude =
			min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
		break;

	case FF_PERIODIC:
		i = apply_envelope(state, abs(new->u.periodic.magnitude),
				   &new->u.periodic.envelope);

		/* here we also scale it 0x7fff => 0xffff */
		i = i * gain / 0x7fff;

		if (effect->u.rumble.strong_magnitude + i)
			effect->direction = ml_calculate_direction(
				effect->direction,
				effect->u.rumble.strong_magnitude,
				new->direction, i);
		else
			effect->direction = 0;
		effect->u.rumble.strong_magnitude =
			min(i + effect->u.rumble.strong_magnitude, 0xffffU);
		effect->u.rumble.weak_magnitude =
			min(i + effect->u.rumble.weak_magnitude, 0xffffU);
		break;

	default:
		pr_err("invalid type in ml_combine_effects()\n");
		break;
	}

}


/*
 * Because memoryless devices have only one effect per effect type active
 * at one time we have to combine multiple effects into one
 */
static int ml_get_combo_effect(struct ml_device *ml,
			       unsigned long *effect_handled,
			       struct ff_effect *combo_effect)
{
	struct ff_effect *effect;
	struct ml_effect_state *state;
	int effect_type;
	int i;

	memset(combo_effect, 0, sizeof(struct ff_effect));

	for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
		if (__test_and_set_bit(i, effect_handled))
			continue;

		state = &ml->states[i];
		effect = state->effect;

		if (!test_bit(FF_EFFECT_STARTED, &state->flags))
			continue;

		if (time_before(jiffies, state->play_at))
			continue;

		/*
		 * here we have started effects that are either
		 * currently playing (and may need be aborted)
		 * or need to start playing.
		 */
		effect_type = get_compatible_type(ml->dev->ff, effect->type);
		if (combo_effect->type != effect_type) {
			if (combo_effect->type != 0) {
				__clear_bit(i, effect_handled);
				continue;
			}
			combo_effect->type = effect_type;
		}

		if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
			__clear_bit(FF_EFFECT_PLAYING, &state->flags);
			__clear_bit(FF_EFFECT_STARTED, &state->flags);
		} else if (effect->replay.length &&
			   time_after_eq(jiffies, state->stop_at)) {

			__clear_bit(FF_EFFECT_PLAYING, &state->flags);

			if (--state->count <= 0) {
				__clear_bit(FF_EFFECT_STARTED, &state->flags);
			} else {
				state->play_at = jiffies +
					msecs_to_jiffies(effect->replay.delay);
				state->stop_at = state->play_at +
					msecs_to_jiffies(effect->replay.length);
			}
		} else {
			__set_bit(FF_EFFECT_PLAYING, &state->flags);
			state->adj_at = jiffies;
			ml_combine_effects(combo_effect, state, ml->gain);
		}
	}

	return combo_effect->type != 0;
}

static void ml_play_effects(struct ml_device *ml)
{
	struct ff_effect effect;
	DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);

	memset(handled_bm, 0, sizeof(handled_bm));

	while (ml_get_combo_effect(ml, handled_bm, &effect))
		ml->play_effect(ml->dev, ml->private, &effect);

	ml_schedule_timer(ml);
}

static void ml_effect_timer(struct timer_list *t)
{
	struct ml_device *ml = from_timer(ml, t, timer);
	struct input_dev *dev = ml->dev;
	unsigned long flags;

	pr_debug("timer: updating effects\n");

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

/*
 * Sets requested gain for FF effects. Called with dev->event_lock held.
 */
static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
{
	struct ml_device *ml = dev->ff->private;
	int i;

	ml->gain = gain;

	for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
		__clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);

	ml_play_effects(ml);
}

/*
 * Start/stop specified FF effect. Called with dev->event_lock held.
 */
static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
{
	struct ml_device *ml = dev->ff->private;
	struct ml_effect_state *state = &ml->states[effect_id];

	if (value > 0) {
		pr_debug("initiated play\n");

		__set_bit(FF_EFFECT_STARTED, &state->flags);
		state->count = value;
		state->play_at = jiffies +
				 msecs_to_jiffies(state->effect->replay.delay);
		state->stop_at = state->play_at +
				 msecs_to_jiffies(state->effect->replay.length);
		state->adj_at = state->play_at;

	} else {
		pr_debug("initiated stop\n");

		if (test_bit(FF_EFFECT_PLAYING, &state->flags))
			__set_bit(FF_EFFECT_ABORTING, &state->flags);
		else
			__clear_bit(FF_EFFECT_STARTED, &state->flags);
	}

	ml_play_effects(ml);

	return 0;
}

static int ml_ff_upload(struct input_dev *dev,
			struct ff_effect *effect, struct ff_effect *old)
{
	struct ml_device *ml = dev->ff->private;
	struct ml_effect_state *state = &ml->states[effect->id];

	spin_lock_irq(&dev->event_lock);

	if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
		__clear_bit(FF_EFFECT_PLAYING, &state->flags);
		state->play_at = jiffies +
				 msecs_to_jiffies(state->effect->replay.delay);
		state->stop_at = state->play_at +
				 msecs_to_jiffies(state->effect->replay.length);
		state->adj_at = state->play_at;
		ml_schedule_timer(ml);
	}

	spin_unlock_irq(&dev->event_lock);

	return 0;
}

static void ml_ff_destroy(struct ff_device *ff)
{
	struct ml_device *ml = ff->private;

	/*
	 * Even though we stop all playing effects when tearing down
	 * an input device (via input_device_flush() that calls into
	 * input_ff_flush() that stops and erases all effects), we
	 * do not actually stop the timer, and therefore we should
	 * do it here.
	 */
	del_timer_sync(&ml->timer);

	kfree(ml->private);
}

/**
 * input_ff_create_memless() - create memoryless force-feedback device
 * @dev: input device supporting force-feedback
 * @data: driver-specific data to be passed into @play_effect
 * @play_effect: driver-specific method for playing FF effect
 */
int input_ff_create_memless(struct input_dev *dev, void *data,
		int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
{
	struct ml_device *ml;
	struct ff_device *ff;
	int error;
	int i;

	ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
	if (!ml)
		return -ENOMEM;

	ml->dev = dev;
	ml->private = data;
	ml->play_effect = play_effect;
	ml->gain = 0xffff;
	timer_setup(&ml->timer, ml_effect_timer, 0);

	set_bit(FF_GAIN, dev->ffbit);

	error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
	if (error) {
		kfree(ml);
		return error;
	}

	ff = dev->ff;
	ff->private = ml;
	ff->upload = ml_ff_upload;
	ff->playback = ml_ff_playback;
	ff->set_gain = ml_ff_set_gain;
	ff->destroy = ml_ff_destroy;

	/* we can emulate periodic effects with RUMBLE */
	if (test_bit(FF_RUMBLE, ff->ffbit)) {
		set_bit(FF_PERIODIC, dev->ffbit);
		set_bit(FF_SINE, dev->ffbit);
		set_bit(FF_TRIANGLE, dev->ffbit);
		set_bit(FF_SQUARE, dev->ffbit);
	}

	for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
		ml->states[i].effect = &ff->effects[i];

	return 0;
}
EXPORT_SYMBOL_GPL(input_ff_create_memless);
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
7d928a2b AH	2	/*
	3	* Force feedback support for memoryless devices
	4	*
	5	* Copyright (c) 2006 Anssi Hannula <[email protected]>
	6	* Copyright (c) 2006 Dmitry Torokhov <[email protected]>
	7	*/
	8
	9	/*
7d928a2b AH	10	*/
	11
	12	/* #define DEBUG */
	13
da0c4901	14	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7d928a2b	15
5a0e3ad6	16	#include <linux/slab.h>
7d928a2b AH	17	#include <linux/input.h>
	18	#include <linux/module.h>
	19	#include <linux/mutex.h>
	20	#include <linux/spinlock.h>
cd354f1a	21	#include <linux/jiffies.h>
c8e1fb4a	22	#include <linux/fixp-arith.h>
7d928a2b AH	23
	24	MODULE_LICENSE("GPL");
	25	MODULE_AUTHOR("Anssi Hannula <[email protected]>");
	26	MODULE_DESCRIPTION("Force feedback support for memoryless devices");
	27
	28	/* Number of effects handled with memoryless devices */
	29	#define FF_MEMLESS_EFFECTS 16
	30
	31	/* Envelope update interval in ms */
	32	#define FF_ENVELOPE_INTERVAL 50
	33
	34	#define FF_EFFECT_STARTED 0
	35	#define FF_EFFECT_PLAYING 1
	36	#define FF_EFFECT_ABORTING 2
	37
	38	struct ml_effect_state {
	39	struct ff_effect *effect;
	40	unsigned long flags; /* effect state (STARTED, PLAYING, etc) */
	41	int count; /* loop count of the effect */
	42	unsigned long play_at; /* start time */
	43	unsigned long stop_at; /* stop time */
	44	unsigned long adj_at; /* last time the effect was sent */
	45	};
	46
	47	struct ml_device {
	48	void *private;
	49	struct ml_effect_state states[FF_MEMLESS_EFFECTS];
	50	int gain;
	51	struct timer_list timer;
7d928a2b AH	52	struct input_dev *dev;
	53
	54	int (play_effect)(struct input_dev dev, void *data,
	55	struct ff_effect *effect);
	56	};
	57
	58	static const struct ff_envelope get_envelope(const struct ff_effect effect)
	59	{
	60	static const struct ff_envelope empty_envelope;
	61
	62	switch (effect->type) {
41091ad0 BC	63	case FF_PERIODIC:
	64	return &effect->u.periodic.envelope;
	65
	66	case FF_CONSTANT:
	67	return &effect->u.constant.envelope;
	68
	69	default:
	70	return &empty_envelope;
7d928a2b AH	71	}
	72	}
	73
	74	/*
	75	* Check for the next time envelope requires an update on memoryless devices
	76	*/
	77	static unsigned long calculate_next_time(struct ml_effect_state *state)
	78	{
	79	const struct ff_envelope *envelope = get_envelope(state->effect);
	80	unsigned long attack_stop, fade_start, next_fade;
	81
	82	if (envelope->attack_length) {
	83	attack_stop = state->play_at +
	84	msecs_to_jiffies(envelope->attack_length);
	85	if (time_before(state->adj_at, attack_stop))
	86	return state->adj_at +
	87	msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
	88	}
	89
	90	if (state->effect->replay.length) {
	91	if (envelope->fade_length) {
	92	/* check when fading should start */
	93	fade_start = state->stop_at -
	94	msecs_to_jiffies(envelope->fade_length);
	95
	96	if (time_before(state->adj_at, fade_start))
	97	return fade_start;
	98
	99	/* already fading, advance to next checkpoint */
	100	next_fade = state->adj_at +
	101	msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
	102	if (time_before(next_fade, state->stop_at))
	103	return next_fade;
	104	}
	105
	106	return state->stop_at;
	107	}
	108
	109	return state->play_at;
	110	}
	111
	112	static void ml_schedule_timer(struct ml_device *ml)
	113	{
	114	struct ml_effect_state *state;
	115	unsigned long now = jiffies;
	116	unsigned long earliest = 0;
	117	unsigned long next_at;
	118	int events = 0;
	119	int i;
	120
da0c4901	121	pr_debug("calculating next timer\n");
7d928a2b AH	122
	123	for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
	124
	125	state = &ml->states[i];
	126
	127	if (!test_bit(FF_EFFECT_STARTED, &state->flags))
	128	continue;
	129
	130	if (test_bit(FF_EFFECT_PLAYING, &state->flags))
	131	next_at = calculate_next_time(state);
	132	else
	133	next_at = state->play_at;
	134
	135	if (time_before_eq(now, next_at) &&
	136	(++events == 1 \|\| time_before(next_at, earliest)))
	137	earliest = next_at;
	138	}
	139
	140	if (!events) {
da0c4901	141	pr_debug("no actions\n");
7d928a2b AH	142	del_timer(&ml->timer);
7d928a2b AH	143	} else {
da0c4901	144	pr_debug("timer set\n");
7d928a2b AH	145	mod_timer(&ml->timer, earliest);
	146	}
	147	}
	148
	149	/*
	150	* Apply an envelope to a value
	151	*/
	152	static int apply_envelope(struct ml_effect_state *state, int value,
	153	struct ff_envelope *envelope)
	154	{
	155	struct ff_effect *effect = state->effect;
	156	unsigned long now = jiffies;
	157	int time_from_level;
	158	int time_of_envelope;
	159	int envelope_level;
	160	int difference;
	161
	162	if (envelope->attack_length &&
	163	time_before(now,
	164	state->play_at + msecs_to_jiffies(envelope->attack_length))) {
da0c4901 JP	165	pr_debug("value = 0x%x, attack_level = 0x%x\n",
da0c4901 JP	166	value, envelope->attack_level);
7d928a2b AH	167	time_from_level = jiffies_to_msecs(now - state->play_at);
7d928a2b AH	168	time_of_envelope = envelope->attack_length;
9a932145	169	envelope_level = min_t(u16, envelope->attack_level, 0x7fff);
7d928a2b AH	170
	171	} else if (envelope->fade_length && effect->replay.length &&
	172	time_after(now,
	173	state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
	174	time_before(now, state->stop_at)) {
	175	time_from_level = jiffies_to_msecs(state->stop_at - now);
	176	time_of_envelope = envelope->fade_length;
9a932145	177	envelope_level = min_t(u16, envelope->fade_level, 0x7fff);
7d928a2b AH	178	} else
	179	return value;
	180
	181	difference = abs(value) - envelope_level;
	182
da0c4901 JP	183	pr_debug("difference = %d\n", difference);
	184	pr_debug("time_from_level = 0x%x\n", time_from_level);
	185	pr_debug("time_of_envelope = 0x%x\n", time_of_envelope);
7d928a2b AH	186
	187	difference = difference * time_from_level / time_of_envelope;
	188
da0c4901	189	pr_debug("difference = %d\n", difference);
7d928a2b AH	190
	191	return value < 0 ?
	192	-(difference + envelope_level) : (difference + envelope_level);
	193	}
	194
	195	/*
	196	* Return the type the effect has to be converted into (memless devices)
	197	*/
	198	static int get_compatible_type(struct ff_device *ff, int effect_type)
	199	{
	200
	201	if (test_bit(effect_type, ff->ffbit))
	202	return effect_type;
	203
	204	if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
	205	return FF_RUMBLE;
	206
da0c4901	207	pr_err("invalid type in get_compatible_type()\n");
7d928a2b AH	208
	209	return 0;
	210	}
	211
94ec26c8 JV	212	/*
	213	* Only left/right direction should be used (under/over 0x8000) for
	214	* forward/reverse motor direction (to keep calculation fast & simple).
	215	*/
	216	static u16 ml_calculate_direction(u16 direction, u16 force,
	217	u16 new_direction, u16 new_force)
	218	{
	219	if (!force)
	220	return new_direction;
	221	if (!new_force)
	222	return direction;
	223	return (((u32)(direction >> 1) * force +
	224	(new_direction >> 1) * new_force) /
	225	(force + new_force)) << 1;
	226	}
	227
559addc2 MCC	228	#define FRAC_N 8
	229	static inline s16 fixp_new16(s16 a)
	230	{
	231	return ((s32)a) >> (16 - FRAC_N);
	232	}
	233
	234	static inline s16 fixp_mult(s16 a, s16 b)
	235	{
	236	a = ((s32)a * 0x100) / 0x7fff;
	237	return ((s32)(a * b)) >> FRAC_N;
	238	}
	239
7d928a2b AH	240	/*
	241	* Combine two effects and apply gain.
	242	*/
	243	static void ml_combine_effects(struct ff_effect *effect,
	244	struct ml_effect_state *state,
1b11c88d	245	int gain)
7d928a2b AH	246	{
	247	struct ff_effect *new = state->effect;
	248	unsigned int strong, weak, i;
	249	int x, y;
559addc2	250	s16 level;
7d928a2b AH	251
	252	switch (new->type) {
	253	case FF_CONSTANT:
	254	i = new->direction * 360 / 0xffff;
	255	level = fixp_new16(apply_envelope(state,
	256	new->u.constant.level,
	257	&new->u.constant.envelope));
559addc2 MCC	258	x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff;
559addc2 MCC	259	y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff;
7d928a2b AH	260	/*
	261	* here we abuse ff_ramp to hold x and y of constant force
	262	* If in future any driver wants something else than x and y
	263	* in s8, this should be changed to something more generic
	264	*/
	265	effect->u.ramp.start_level =
92310474	266	clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
7d928a2b	267	effect->u.ramp.end_level =
92310474	268	clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
7d928a2b AH	269	break;
	270
	271	case FF_RUMBLE:
1b11c88d DT	272	strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
1b11c88d DT	273	weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
94ec26c8 JV	274
	275	if (effect->u.rumble.strong_magnitude + strong)
	276	effect->direction = ml_calculate_direction(
	277	effect->direction,
	278	effect->u.rumble.strong_magnitude,
	279	new->direction, strong);
	280	else if (effect->u.rumble.weak_magnitude + weak)
	281	effect->direction = ml_calculate_direction(
	282	effect->direction,
	283	effect->u.rumble.weak_magnitude,
	284	new->direction, weak);
	285	else
	286	effect->direction = 0;
7d928a2b AH	287	effect->u.rumble.strong_magnitude =
	288	min(strong + effect->u.rumble.strong_magnitude,
	289	0xffffU);
	290	effect->u.rumble.weak_magnitude =
	291	min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
	292	break;
	293
	294	case FF_PERIODIC:
	295	i = apply_envelope(state, abs(new->u.periodic.magnitude),
	296	&new->u.periodic.envelope);
	297
	298	/* here we also scale it 0x7fff => 0xffff */
	299	i = i * gain / 0x7fff;
	300
94ec26c8 JV	301	if (effect->u.rumble.strong_magnitude + i)
	302	effect->direction = ml_calculate_direction(
	303	effect->direction,
	304	effect->u.rumble.strong_magnitude,
	305	new->direction, i);
	306	else
	307	effect->direction = 0;
7d928a2b AH	308	effect->u.rumble.strong_magnitude =
	309	min(i + effect->u.rumble.strong_magnitude, 0xffffU);
	310	effect->u.rumble.weak_magnitude =
	311	min(i + effect->u.rumble.weak_magnitude, 0xffffU);
	312	break;
	313
	314	default:
da0c4901	315	pr_err("invalid type in ml_combine_effects()\n");
7d928a2b AH	316	break;
	317	}
	318
	319	}
	320
	321
	322	/*
	323	* Because memoryless devices have only one effect per effect type active
	324	* at one time we have to combine multiple effects into one
	325	*/
	326	static int ml_get_combo_effect(struct ml_device *ml,
	327	unsigned long *effect_handled,
	328	struct ff_effect *combo_effect)
	329	{
	330	struct ff_effect *effect;
	331	struct ml_effect_state *state;
	332	int effect_type;
	333	int i;
	334
	335	memset(combo_effect, 0, sizeof(struct ff_effect));
	336
	337	for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
	338	if (__test_and_set_bit(i, effect_handled))
	339	continue;
	340
	341	state = &ml->states[i];
	342	effect = state->effect;
	343
	344	if (!test_bit(FF_EFFECT_STARTED, &state->flags))
	345	continue;
	346
	347	if (time_before(jiffies, state->play_at))
	348	continue;
	349
	350	/*
	351	* here we have started effects that are either
	352	* currently playing (and may need be aborted)
	353	* or need to start playing.
	354	*/
	355	effect_type = get_compatible_type(ml->dev->ff, effect->type);
	356	if (combo_effect->type != effect_type) {
	357	if (combo_effect->type != 0) {
	358	__clear_bit(i, effect_handled);
	359	continue;
	360	}
	361	combo_effect->type = effect_type;
	362	}
	363
	364	if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
	365	__clear_bit(FF_EFFECT_PLAYING, &state->flags);
	366	__clear_bit(FF_EFFECT_STARTED, &state->flags);
	367	} else if (effect->replay.length &&
	368	time_after_eq(jiffies, state->stop_at)) {
	369
	370	__clear_bit(FF_EFFECT_PLAYING, &state->flags);
	371
	372	if (--state->count <= 0) {
	373	__clear_bit(FF_EFFECT_STARTED, &state->flags);
	374	} else {
	375	state->play_at = jiffies +
	376	msecs_to_jiffies(effect->replay.delay);
	377	state->stop_at = state->play_at +
	378	msecs_to_jiffies(effect->replay.length);
	379	}
380	} else {
381	__set_bit(FF_EFFECT_PLAYING, &state->flags);
382	state->adj_at = jiffies;
383	ml_combine_effects(combo_effect, state, ml->gain);
384	}
385	}
386
387	return combo_effect->type != 0;
388	}
389
390	static void ml_play_effects(struct ml_device *ml)
391	{
392	struct ff_effect effect;
393	DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
394
395	memset(handled_bm, 0, sizeof(handled_bm));
396
397	while (ml_get_combo_effect(ml, handled_bm, &effect))
398	ml->play_effect(ml->dev, ml->private, &effect);
399
400	ml_schedule_timer(ml);
401	}
402
34445d4b	403	static void ml_effect_timer(struct timer_list *t)
7d928a2b	404	{
34445d4b KC	405	struct ml_device *ml = from_timer(ml, t, timer);
34445d4b KC	406	struct input_dev *dev = ml->dev;
bf3204cb	407	unsigned long flags;
7d928a2b	408
da0c4901	409	pr_debug("timer: updating effects\n");
7d928a2b	410
bf3204cb	411	spin_lock_irqsave(&dev->event_lock, flags);
7d928a2b	412	ml_play_effects(ml);
bf3204cb	413	spin_unlock_irqrestore(&dev->event_lock, flags);
7d928a2b AH	414	}
7d928a2b AH	415
bf3204cb DT	416	/*
	417	* Sets requested gain for FF effects. Called with dev->event_lock held.
	418	*/
7d928a2b AH	419	static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
	420	{
	421	struct ml_device *ml = dev->ff->private;
	422	int i;
	423
7d928a2b AH	424	ml->gain = gain;
	425
	426	for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
	427	__clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
	428
	429	ml_play_effects(ml);
7d928a2b AH	430	}
7d928a2b AH	431
bf3204cb DT	432	/*
	433	* Start/stop specified FF effect. Called with dev->event_lock held.
	434	*/
7d928a2b AH	435	static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
	436	{
	437	struct ml_device *ml = dev->ff->private;
	438	struct ml_effect_state *state = &ml->states[effect_id];
7d928a2b AH	439
7d928a2b AH	440	if (value > 0) {
da0c4901	441	pr_debug("initiated play\n");
7d928a2b AH	442
	443	__set_bit(FF_EFFECT_STARTED, &state->flags);
	444	state->count = value;
	445	state->play_at = jiffies +
	446	msecs_to_jiffies(state->effect->replay.delay);
	447	state->stop_at = state->play_at +
	448	msecs_to_jiffies(state->effect->replay.length);
	449	state->adj_at = state->play_at;
	450
7d928a2b	451	} else {
da0c4901	452	pr_debug("initiated stop\n");
7d928a2b AH	453
	454	if (test_bit(FF_EFFECT_PLAYING, &state->flags))
	455	__set_bit(FF_EFFECT_ABORTING, &state->flags);
	456	else
	457	__clear_bit(FF_EFFECT_STARTED, &state->flags);
7d928a2b AH	458	}
7d928a2b AH	459
25ae0831 JV	460	ml_play_effects(ml);
25ae0831 JV	461
7d928a2b AH	462	return 0;
	463	}
	464
	465	static int ml_ff_upload(struct input_dev *dev,
	466	struct ff_effect effect, struct ff_effect old)
	467	{
	468	struct ml_device *ml = dev->ff->private;
	469	struct ml_effect_state *state = &ml->states[effect->id];
	470
bf3204cb	471	spin_lock_irq(&dev->event_lock);
7d928a2b AH	472
	473	if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
	474	__clear_bit(FF_EFFECT_PLAYING, &state->flags);
	475	state->play_at = jiffies +
	476	msecs_to_jiffies(state->effect->replay.delay);
	477	state->stop_at = state->play_at +
	478	msecs_to_jiffies(state->effect->replay.length);
	479	state->adj_at = state->play_at;
	480	ml_schedule_timer(ml);
	481	}
	482
bf3204cb	483	spin_unlock_irq(&dev->event_lock);
7d928a2b AH	484
	485	return 0;
	486	}
	487
	488	static void ml_ff_destroy(struct ff_device *ff)
	489	{
	490	struct ml_device *ml = ff->private;
	491
fa3a5a18 ON	492	/*
	493	* Even though we stop all playing effects when tearing down
	494	* an input device (via input_device_flush() that calls into
	495	* input_ff_flush() that stops and erases all effects), we
	496	* do not actually stop the timer, and therefore we should
	497	* do it here.
	498	*/
	499	del_timer_sync(&ml->timer);
	500
7d928a2b AH	501	kfree(ml->private);
	502	}
	503
	504	/**
e4477d2d	505	* input_ff_create_memless() - create memoryless force-feedback device
7d928a2b AH	506	* @dev: input device supporting force-feedback
	507	* @data: driver-specific data to be passed into @play_effect
	508	* @play_effect: driver-specific method for playing FF effect
	509	*/
	510	int input_ff_create_memless(struct input_dev dev, void data,
	511	int (play_effect)(struct input_dev , void , struct ff_effect ))
	512	{
	513	struct ml_device *ml;
	514	struct ff_device *ff;
	515	int error;
	516	int i;
	517
	518	ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
	519	if (!ml)
	520	return -ENOMEM;
	521
	522	ml->dev = dev;
	523	ml->private = data;
	524	ml->play_effect = play_effect;
	525	ml->gain = 0xffff;
34445d4b	526	timer_setup(&ml->timer, ml_effect_timer, 0);
7d928a2b AH	527
	528	set_bit(FF_GAIN, dev->ffbit);
	529
	530	error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
	531	if (error) {
	532	kfree(ml);
	533	return error;
	534	}
	535
	536	ff = dev->ff;
	537	ff->private = ml;
	538	ff->upload = ml_ff_upload;
	539	ff->playback = ml_ff_playback;
	540	ff->set_gain = ml_ff_set_gain;
	541	ff->destroy = ml_ff_destroy;
	542
	543	/* we can emulate periodic effects with RUMBLE */
	544	if (test_bit(FF_RUMBLE, ff->ffbit)) {
	545	set_bit(FF_PERIODIC, dev->ffbit);
	546	set_bit(FF_SINE, dev->ffbit);
	547	set_bit(FF_TRIANGLE, dev->ffbit);
	548	set_bit(FF_SQUARE, dev->ffbit);
	549	}
	550
	551	for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
	552	ml->states[i].effect = &ff->effects[i];
	553
	554	return 0;
	555	}
	556	EXPORT_SYMBOL_GPL(input_ff_create_memless);