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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Force feedback support for memoryless devices
4 *
5 * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
6 * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
7 */
8
9/*
10 */
11
12/* #define DEBUG */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/slab.h>
17#include <linux/input.h>
18#include <linux/module.h>
19#include <linux/mutex.h>
20#include <linux/spinlock.h>
21#include <linux/jiffies.h>
22#include <linux/fixp-arith.h>
23
24MODULE_LICENSE("GPL");
25MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
26MODULE_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
38struct 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
47struct ml_device {
48 void *private;
49 struct ml_effect_state states[FF_MEMLESS_EFFECTS];
50 int gain;
51 struct timer_list timer;
52 struct input_dev *dev;
53
54 int (*play_effect)(struct input_dev *dev, void *data,
55 struct ff_effect *effect);
56};
57
58static 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) {
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;
71 }
72}
73
74/*
75 * Check for the next time envelope requires an update on memoryless devices
76 */
77static 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
112static 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
121 pr_debug("calculating next timer\n");
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) {
141 pr_debug("no actions\n");
142 del_timer(&ml->timer);
143 } else {
144 pr_debug("timer set\n");
145 mod_timer(&ml->timer, earliest);
146 }
147}
148
149/*
150 * Apply an envelope to a value
151 */
152static 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))) {
165 pr_debug("value = 0x%x, attack_level = 0x%x\n",
166 value, envelope->attack_level);
167 time_from_level = jiffies_to_msecs(now - state->play_at);
168 time_of_envelope = envelope->attack_length;
169 envelope_level = min_t(u16, envelope->attack_level, 0x7fff);
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;
177 envelope_level = min_t(u16, envelope->fade_level, 0x7fff);
178 } else
179 return value;
180
181 difference = abs(value) - envelope_level;
182
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);
186
187 difference = difference * time_from_level / time_of_envelope;
188
189 pr_debug("difference = %d\n", difference);
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 */
198static 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
207 pr_err("invalid type in get_compatible_type()\n");
208
209 return 0;
210}
211
212/*
213 * Only left/right direction should be used (under/over 0x8000) for
214 * forward/reverse motor direction (to keep calculation fast & simple).
215 */
216static 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
228#define FRAC_N 8
229static inline s16 fixp_new16(s16 a)
230{
231 return ((s32)a) >> (16 - FRAC_N);
232}
233
234static inline s16 fixp_mult(s16 a, s16 b)
235{
236 a = ((s32)a * 0x100) / 0x7fff;
237 return ((s32)(a * b)) >> FRAC_N;
238}
239
240/*
241 * Combine two effects and apply gain.
242 */
243static void ml_combine_effects(struct ff_effect *effect,
244 struct ml_effect_state *state,
245 int gain)
246{
247 struct ff_effect *new = state->effect;
248 unsigned int strong, weak, i;
249 int x, y;
250 s16 level;
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));
258 x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff;
259 y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff;
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 =
266 clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
267 effect->u.ramp.end_level =
268 clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
269 break;
270
271 case FF_RUMBLE:
272 strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
273 weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
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;
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
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;
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:
315 pr_err("invalid type in ml_combine_effects()\n");
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 */
326static 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
390static 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
403static void ml_effect_timer(struct timer_list *t)
404{
405 struct ml_device *ml = from_timer(ml, t, timer);
406 struct input_dev *dev = ml->dev;
407 unsigned long flags;
408
409 pr_debug("timer: updating effects\n");
410
411 spin_lock_irqsave(&dev->event_lock, flags);
412 ml_play_effects(ml);
413 spin_unlock_irqrestore(&dev->event_lock, flags);
414}
415
416/*
417 * Sets requested gain for FF effects. Called with dev->event_lock held.
418 */
419static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
420{
421 struct ml_device *ml = dev->ff->private;
422 int i;
423
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);
430}
431
432/*
433 * Start/stop specified FF effect. Called with dev->event_lock held.
434 */
435static 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];
439
440 if (value > 0) {
441 pr_debug("initiated play\n");
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
451 } else {
452 pr_debug("initiated stop\n");
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);
458 }
459
460 ml_play_effects(ml);
461
462 return 0;
463}
464
465static 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
471 spin_lock_irq(&dev->event_lock);
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
483 spin_unlock_irq(&dev->event_lock);
484
485 return 0;
486}
487
488static void ml_ff_destroy(struct ff_device *ff)
489{
490 struct ml_device *ml = ff->private;
491
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
501 kfree(ml->private);
502}
503
504/**
505 * input_ff_create_memless() - create memoryless force-feedback device
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 */
510int 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;
526 timer_setup(&ml->timer, ml_effect_timer, 0);
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}
556EXPORT_SYMBOL_GPL(input_ff_create_memless);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Force feedback support for memoryless devices
4 *
5 * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
6 * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
7 */
8
9/* #define DEBUG */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/slab.h>
14#include <linux/input.h>
15#include <linux/module.h>
16#include <linux/mutex.h>
17#include <linux/spinlock.h>
18#include <linux/jiffies.h>
19#include <linux/fixp-arith.h>
20
21MODULE_LICENSE("GPL");
22MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
23MODULE_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
35struct 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
44struct ml_device {
45 void *private;
46 struct ml_effect_state states[FF_MEMLESS_EFFECTS];
47 int gain;
48 struct timer_list timer;
49 struct input_dev *dev;
50
51 int (*play_effect)(struct input_dev *dev, void *data,
52 struct ff_effect *effect);
53};
54
55static 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) {
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;
68 }
69}
70
71/*
72 * Check for the next time envelope requires an update on memoryless devices
73 */
74static 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
109static 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
118 pr_debug("calculating next timer\n");
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) {
138 pr_debug("no actions\n");
139 del_timer(&ml->timer);
140 } else {
141 pr_debug("timer set\n");
142 mod_timer(&ml->timer, earliest);
143 }
144}
145
146/*
147 * Apply an envelope to a value
148 */
149static 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))) {
162 pr_debug("value = 0x%x, attack_level = 0x%x\n",
163 value, envelope->attack_level);
164 time_from_level = jiffies_to_msecs(now - state->play_at);
165 time_of_envelope = envelope->attack_length;
166 envelope_level = min_t(u16, envelope->attack_level, 0x7fff);
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;
174 envelope_level = min_t(u16, envelope->fade_level, 0x7fff);
175 } else
176 return value;
177
178 difference = abs(value) - envelope_level;
179
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);
183
184 difference = difference * time_from_level / time_of_envelope;
185
186 pr_debug("difference = %d\n", difference);
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 */
195static 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
204 pr_err("invalid type in get_compatible_type()\n");
205
206 return 0;
207}
208
209/*
210 * Only left/right direction should be used (under/over 0x8000) for
211 * forward/reverse motor direction (to keep calculation fast & simple).
212 */
213static 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
225#define FRAC_N 8
226static inline s16 fixp_new16(s16 a)
227{
228 return ((s32)a) >> (16 - FRAC_N);
229}
230
231static inline s16 fixp_mult(s16 a, s16 b)
232{
233 a = ((s32)a * 0x100) / 0x7fff;
234 return ((s32)(a * b)) >> FRAC_N;
235}
236
237/*
238 * Combine two effects and apply gain.
239 */
240static void ml_combine_effects(struct ff_effect *effect,
241 struct ml_effect_state *state,
242 int gain)
243{
244 struct ff_effect *new = state->effect;
245 unsigned int strong, weak, i;
246 int x, y;
247 s16 level;
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));
255 x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff;
256 y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff;
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 =
263 clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
264 effect->u.ramp.end_level =
265 clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
266 break;
267
268 case FF_RUMBLE:
269 strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
270 weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
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;
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
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;
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:
312 pr_err("invalid type in ml_combine_effects()\n");
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 */
323static 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
387static 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
400static void ml_effect_timer(struct timer_list *t)
401{
402 struct ml_device *ml = from_timer(ml, t, timer);
403 struct input_dev *dev = ml->dev;
404 unsigned long flags;
405
406 pr_debug("timer: updating effects\n");
407
408 spin_lock_irqsave(&dev->event_lock, flags);
409 ml_play_effects(ml);
410 spin_unlock_irqrestore(&dev->event_lock, flags);
411}
412
413/*
414 * Sets requested gain for FF effects. Called with dev->event_lock held.
415 */
416static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
417{
418 struct ml_device *ml = dev->ff->private;
419 int i;
420
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);
427}
428
429/*
430 * Start/stop specified FF effect. Called with dev->event_lock held.
431 */
432static 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];
436
437 if (value > 0) {
438 pr_debug("initiated play\n");
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
448 } else {
449 pr_debug("initiated stop\n");
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);
455 }
456
457 ml_play_effects(ml);
458
459 return 0;
460}
461
462static 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
468 spin_lock_irq(&dev->event_lock);
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
480 spin_unlock_irq(&dev->event_lock);
481
482 return 0;
483}
484
485static void ml_ff_destroy(struct ff_device *ff)
486{
487 struct ml_device *ml = ff->private;
488
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
498 kfree(ml->private);
499}
500
501/**
502 * input_ff_create_memless() - create memoryless force-feedback device
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 */
507int 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;
523 timer_setup(&ml->timer, ml_effect_timer, 0);
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}
553EXPORT_SYMBOL_GPL(input_ff_create_memless);