summaryrefslogtreecommitdiffstats
path: root/drivers/input/ff-memless.c
blob: 1cd23bf3236c2e577317b68c69cc86b2ab832cc2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
/*
 *  Force feedback support for memoryless devices
 *
 *  Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
 *  Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
 */

/*
 * 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 */

#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 <anssi.hannula@gmail.com>");
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);