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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/*
2 * Force feedback support for memoryless devices
3 *
4 * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
5 * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
6 */
7
8/*
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 */
23
24/* #define DEBUG */
25
26#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27
28#include <linux/slab.h>
29#include <linux/input.h>
30#include <linux/module.h>
31#include <linux/mutex.h>
32#include <linux/spinlock.h>
33#include <linux/jiffies.h>
34#include <linux/fixp-arith.h>
35
36MODULE_LICENSE("GPL");
37MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
38MODULE_DESCRIPTION("Force feedback support for memoryless devices");
39
40/* Number of effects handled with memoryless devices */
41#define FF_MEMLESS_EFFECTS 16
42
43/* Envelope update interval in ms */
44#define FF_ENVELOPE_INTERVAL 50
45
46#define FF_EFFECT_STARTED 0
47#define FF_EFFECT_PLAYING 1
48#define FF_EFFECT_ABORTING 2
49
50struct ml_effect_state {
51 struct ff_effect *effect;
52 unsigned long flags; /* effect state (STARTED, PLAYING, etc) */
53 int count; /* loop count of the effect */
54 unsigned long play_at; /* start time */
55 unsigned long stop_at; /* stop time */
56 unsigned long adj_at; /* last time the effect was sent */
57};
58
59struct ml_device {
60 void *private;
61 struct ml_effect_state states[FF_MEMLESS_EFFECTS];
62 int gain;
63 struct timer_list timer;
64 struct input_dev *dev;
65
66 int (*play_effect)(struct input_dev *dev, void *data,
67 struct ff_effect *effect);
68};
69
70static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
71{
72 static const struct ff_envelope empty_envelope;
73
74 switch (effect->type) {
75 case FF_PERIODIC:
76 return &effect->u.periodic.envelope;
77 case FF_CONSTANT:
78 return &effect->u.constant.envelope;
79 default:
80 return &empty_envelope;
81 }
82}
83
84/*
85 * Check for the next time envelope requires an update on memoryless devices
86 */
87static unsigned long calculate_next_time(struct ml_effect_state *state)
88{
89 const struct ff_envelope *envelope = get_envelope(state->effect);
90 unsigned long attack_stop, fade_start, next_fade;
91
92 if (envelope->attack_length) {
93 attack_stop = state->play_at +
94 msecs_to_jiffies(envelope->attack_length);
95 if (time_before(state->adj_at, attack_stop))
96 return state->adj_at +
97 msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
98 }
99
100 if (state->effect->replay.length) {
101 if (envelope->fade_length) {
102 /* check when fading should start */
103 fade_start = state->stop_at -
104 msecs_to_jiffies(envelope->fade_length);
105
106 if (time_before(state->adj_at, fade_start))
107 return fade_start;
108
109 /* already fading, advance to next checkpoint */
110 next_fade = state->adj_at +
111 msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
112 if (time_before(next_fade, state->stop_at))
113 return next_fade;
114 }
115
116 return state->stop_at;
117 }
118
119 return state->play_at;
120}
121
122static void ml_schedule_timer(struct ml_device *ml)
123{
124 struct ml_effect_state *state;
125 unsigned long now = jiffies;
126 unsigned long earliest = 0;
127 unsigned long next_at;
128 int events = 0;
129 int i;
130
131 pr_debug("calculating next timer\n");
132
133 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
134
135 state = &ml->states[i];
136
137 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
138 continue;
139
140 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
141 next_at = calculate_next_time(state);
142 else
143 next_at = state->play_at;
144
145 if (time_before_eq(now, next_at) &&
146 (++events == 1 || time_before(next_at, earliest)))
147 earliest = next_at;
148 }
149
150 if (!events) {
151 pr_debug("no actions\n");
152 del_timer(&ml->timer);
153 } else {
154 pr_debug("timer set\n");
155 mod_timer(&ml->timer, earliest);
156 }
157}
158
159/*
160 * Apply an envelope to a value
161 */
162static int apply_envelope(struct ml_effect_state *state, int value,
163 struct ff_envelope *envelope)
164{
165 struct ff_effect *effect = state->effect;
166 unsigned long now = jiffies;
167 int time_from_level;
168 int time_of_envelope;
169 int envelope_level;
170 int difference;
171
172 if (envelope->attack_length &&
173 time_before(now,
174 state->play_at + msecs_to_jiffies(envelope->attack_length))) {
175 pr_debug("value = 0x%x, attack_level = 0x%x\n",
176 value, envelope->attack_level);
177 time_from_level = jiffies_to_msecs(now - state->play_at);
178 time_of_envelope = envelope->attack_length;
179 envelope_level = min_t(__s16, envelope->attack_level, 0x7fff);
180
181 } else if (envelope->fade_length && effect->replay.length &&
182 time_after(now,
183 state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
184 time_before(now, state->stop_at)) {
185 time_from_level = jiffies_to_msecs(state->stop_at - now);
186 time_of_envelope = envelope->fade_length;
187 envelope_level = min_t(__s16, envelope->fade_level, 0x7fff);
188 } else
189 return value;
190
191 difference = abs(value) - envelope_level;
192
193 pr_debug("difference = %d\n", difference);
194 pr_debug("time_from_level = 0x%x\n", time_from_level);
195 pr_debug("time_of_envelope = 0x%x\n", time_of_envelope);
196
197 difference = difference * time_from_level / time_of_envelope;
198
199 pr_debug("difference = %d\n", difference);
200
201 return value < 0 ?
202 -(difference + envelope_level) : (difference + envelope_level);
203}
204
205/*
206 * Return the type the effect has to be converted into (memless devices)
207 */
208static int get_compatible_type(struct ff_device *ff, int effect_type)
209{
210
211 if (test_bit(effect_type, ff->ffbit))
212 return effect_type;
213
214 if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
215 return FF_RUMBLE;
216
217 pr_err("invalid type in get_compatible_type()\n");
218
219 return 0;
220}
221
222/*
223 * Only left/right direction should be used (under/over 0x8000) for
224 * forward/reverse motor direction (to keep calculation fast & simple).
225 */
226static u16 ml_calculate_direction(u16 direction, u16 force,
227 u16 new_direction, u16 new_force)
228{
229 if (!force)
230 return new_direction;
231 if (!new_force)
232 return direction;
233 return (((u32)(direction >> 1) * force +
234 (new_direction >> 1) * new_force) /
235 (force + new_force)) << 1;
236}
237
238/*
239 * Combine two effects and apply gain.
240 */
241static void ml_combine_effects(struct ff_effect *effect,
242 struct ml_effect_state *state,
243 int gain)
244{
245 struct ff_effect *new = state->effect;
246 unsigned int strong, weak, i;
247 int x, y;
248 fixp_t level;
249
250 switch (new->type) {
251 case FF_CONSTANT:
252 i = new->direction * 360 / 0xffff;
253 level = fixp_new16(apply_envelope(state,
254 new->u.constant.level,
255 &new->u.constant.envelope));
256 x = fixp_mult(fixp_sin(i), level) * gain / 0xffff;
257 y = fixp_mult(-fixp_cos(i), level) * gain / 0xffff;
258 /*
259 * here we abuse ff_ramp to hold x and y of constant force
260 * If in future any driver wants something else than x and y
261 * in s8, this should be changed to something more generic
262 */
263 effect->u.ramp.start_level =
264 clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
265 effect->u.ramp.end_level =
266 clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
267 break;
268
269 case FF_RUMBLE:
270 strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
271 weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
272
273 if (effect->u.rumble.strong_magnitude + strong)
274 effect->direction = ml_calculate_direction(
275 effect->direction,
276 effect->u.rumble.strong_magnitude,
277 new->direction, strong);
278 else if (effect->u.rumble.weak_magnitude + weak)
279 effect->direction = ml_calculate_direction(
280 effect->direction,
281 effect->u.rumble.weak_magnitude,
282 new->direction, weak);
283 else
284 effect->direction = 0;
285 effect->u.rumble.strong_magnitude =
286 min(strong + effect->u.rumble.strong_magnitude,
287 0xffffU);
288 effect->u.rumble.weak_magnitude =
289 min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
290 break;
291
292 case FF_PERIODIC:
293 i = apply_envelope(state, abs(new->u.periodic.magnitude),
294 &new->u.periodic.envelope);
295
296 /* here we also scale it 0x7fff => 0xffff */
297 i = i * gain / 0x7fff;
298
299 if (effect->u.rumble.strong_magnitude + i)
300 effect->direction = ml_calculate_direction(
301 effect->direction,
302 effect->u.rumble.strong_magnitude,
303 new->direction, i);
304 else
305 effect->direction = 0;
306 effect->u.rumble.strong_magnitude =
307 min(i + effect->u.rumble.strong_magnitude, 0xffffU);
308 effect->u.rumble.weak_magnitude =
309 min(i + effect->u.rumble.weak_magnitude, 0xffffU);
310 break;
311
312 default:
313 pr_err("invalid type in ml_combine_effects()\n");
314 break;
315 }
316
317}
318
319
320/*
321 * Because memoryless devices have only one effect per effect type active
322 * at one time we have to combine multiple effects into one
323 */
324static int ml_get_combo_effect(struct ml_device *ml,
325 unsigned long *effect_handled,
326 struct ff_effect *combo_effect)
327{
328 struct ff_effect *effect;
329 struct ml_effect_state *state;
330 int effect_type;
331 int i;
332
333 memset(combo_effect, 0, sizeof(struct ff_effect));
334
335 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
336 if (__test_and_set_bit(i, effect_handled))
337 continue;
338
339 state = &ml->states[i];
340 effect = state->effect;
341
342 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
343 continue;
344
345 if (time_before(jiffies, state->play_at))
346 continue;
347
348 /*
349 * here we have started effects that are either
350 * currently playing (and may need be aborted)
351 * or need to start playing.
352 */
353 effect_type = get_compatible_type(ml->dev->ff, effect->type);
354 if (combo_effect->type != effect_type) {
355 if (combo_effect->type != 0) {
356 __clear_bit(i, effect_handled);
357 continue;
358 }
359 combo_effect->type = effect_type;
360 }
361
362 if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
363 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
364 __clear_bit(FF_EFFECT_STARTED, &state->flags);
365 } else if (effect->replay.length &&
366 time_after_eq(jiffies, state->stop_at)) {
367
368 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
369
370 if (--state->count <= 0) {
371 __clear_bit(FF_EFFECT_STARTED, &state->flags);
372 } else {
373 state->play_at = jiffies +
374 msecs_to_jiffies(effect->replay.delay);
375 state->stop_at = state->play_at +
376 msecs_to_jiffies(effect->replay.length);
377 }
378 } else {
379 __set_bit(FF_EFFECT_PLAYING, &state->flags);
380 state->adj_at = jiffies;
381 ml_combine_effects(combo_effect, state, ml->gain);
382 }
383 }
384
385 return combo_effect->type != 0;
386}
387
388static void ml_play_effects(struct ml_device *ml)
389{
390 struct ff_effect effect;
391 DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
392
393 memset(handled_bm, 0, sizeof(handled_bm));
394
395 while (ml_get_combo_effect(ml, handled_bm, &effect))
396 ml->play_effect(ml->dev, ml->private, &effect);
397
398 ml_schedule_timer(ml);
399}
400
401static void ml_effect_timer(unsigned long timer_data)
402{
403 struct input_dev *dev = (struct input_dev *)timer_data;
404 struct ml_device *ml = dev->ff->private;
405 unsigned long flags;
406
407 pr_debug("timer: updating effects\n");
408
409 spin_lock_irqsave(&dev->event_lock, flags);
410 ml_play_effects(ml);
411 spin_unlock_irqrestore(&dev->event_lock, flags);
412}
413
414/*
415 * Sets requested gain for FF effects. Called with dev->event_lock held.
416 */
417static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
418{
419 struct ml_device *ml = dev->ff->private;
420 int i;
421
422 ml->gain = gain;
423
424 for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
425 __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
426
427 ml_play_effects(ml);
428}
429
430/*
431 * Start/stop specified FF effect. Called with dev->event_lock held.
432 */
433static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
434{
435 struct ml_device *ml = dev->ff->private;
436 struct ml_effect_state *state = &ml->states[effect_id];
437
438 if (value > 0) {
439 pr_debug("initiated play\n");
440
441 __set_bit(FF_EFFECT_STARTED, &state->flags);
442 state->count = value;
443 state->play_at = jiffies +
444 msecs_to_jiffies(state->effect->replay.delay);
445 state->stop_at = state->play_at +
446 msecs_to_jiffies(state->effect->replay.length);
447 state->adj_at = state->play_at;
448
449 } else {
450 pr_debug("initiated stop\n");
451
452 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
453 __set_bit(FF_EFFECT_ABORTING, &state->flags);
454 else
455 __clear_bit(FF_EFFECT_STARTED, &state->flags);
456 }
457
458 ml_play_effects(ml);
459
460 return 0;
461}
462
463static int ml_ff_upload(struct input_dev *dev,
464 struct ff_effect *effect, struct ff_effect *old)
465{
466 struct ml_device *ml = dev->ff->private;
467 struct ml_effect_state *state = &ml->states[effect->id];
468
469 spin_lock_irq(&dev->event_lock);
470
471 if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
472 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
473 state->play_at = jiffies +
474 msecs_to_jiffies(state->effect->replay.delay);
475 state->stop_at = state->play_at +
476 msecs_to_jiffies(state->effect->replay.length);
477 state->adj_at = state->play_at;
478 ml_schedule_timer(ml);
479 }
480
481 spin_unlock_irq(&dev->event_lock);
482
483 return 0;
484}
485
486static void ml_ff_destroy(struct ff_device *ff)
487{
488 struct ml_device *ml = ff->private;
489
490 kfree(ml->private);
491}
492
493/**
494 * input_ff_create_memless() - create memoryless force-feedback device
495 * @dev: input device supporting force-feedback
496 * @data: driver-specific data to be passed into @play_effect
497 * @play_effect: driver-specific method for playing FF effect
498 */
499int input_ff_create_memless(struct input_dev *dev, void *data,
500 int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
501{
502 struct ml_device *ml;
503 struct ff_device *ff;
504 int error;
505 int i;
506
507 ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
508 if (!ml)
509 return -ENOMEM;
510
511 ml->dev = dev;
512 ml->private = data;
513 ml->play_effect = play_effect;
514 ml->gain = 0xffff;
515 setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
516
517 set_bit(FF_GAIN, dev->ffbit);
518
519 error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
520 if (error) {
521 kfree(ml);
522 return error;
523 }
524
525 ff = dev->ff;
526 ff->private = ml;
527 ff->upload = ml_ff_upload;
528 ff->playback = ml_ff_playback;
529 ff->set_gain = ml_ff_set_gain;
530 ff->destroy = ml_ff_destroy;
531
532 /* we can emulate periodic effects with RUMBLE */
533 if (test_bit(FF_RUMBLE, ff->ffbit)) {
534 set_bit(FF_PERIODIC, dev->ffbit);
535 set_bit(FF_SINE, dev->ffbit);
536 set_bit(FF_TRIANGLE, dev->ffbit);
537 set_bit(FF_SQUARE, dev->ffbit);
538 }
539
540 for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
541 ml->states[i].effect = &ff->effects[i];
542
543 return 0;
544}
545EXPORT_SYMBOL_GPL(input_ff_create_memless);