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