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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
78 case FF_CONSTANT:
79 return &effect->u.constant.envelope;
80
81 default:
82 return &empty_envelope;
83 }
84}
85
86/*
87 * Check for the next time envelope requires an update on memoryless devices
88 */
89static unsigned long calculate_next_time(struct ml_effect_state *state)
90{
91 const struct ff_envelope *envelope = get_envelope(state->effect);
92 unsigned long attack_stop, fade_start, next_fade;
93
94 if (envelope->attack_length) {
95 attack_stop = state->play_at +
96 msecs_to_jiffies(envelope->attack_length);
97 if (time_before(state->adj_at, attack_stop))
98 return state->adj_at +
99 msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
100 }
101
102 if (state->effect->replay.length) {
103 if (envelope->fade_length) {
104 /* check when fading should start */
105 fade_start = state->stop_at -
106 msecs_to_jiffies(envelope->fade_length);
107
108 if (time_before(state->adj_at, fade_start))
109 return fade_start;
110
111 /* already fading, advance to next checkpoint */
112 next_fade = state->adj_at +
113 msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
114 if (time_before(next_fade, state->stop_at))
115 return next_fade;
116 }
117
118 return state->stop_at;
119 }
120
121 return state->play_at;
122}
123
124static void ml_schedule_timer(struct ml_device *ml)
125{
126 struct ml_effect_state *state;
127 unsigned long now = jiffies;
128 unsigned long earliest = 0;
129 unsigned long next_at;
130 int events = 0;
131 int i;
132
133 pr_debug("calculating next timer\n");
134
135 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
136
137 state = &ml->states[i];
138
139 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
140 continue;
141
142 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
143 next_at = calculate_next_time(state);
144 else
145 next_at = state->play_at;
146
147 if (time_before_eq(now, next_at) &&
148 (++events == 1 || time_before(next_at, earliest)))
149 earliest = next_at;
150 }
151
152 if (!events) {
153 pr_debug("no actions\n");
154 del_timer(&ml->timer);
155 } else {
156 pr_debug("timer set\n");
157 mod_timer(&ml->timer, earliest);
158 }
159}
160
161/*
162 * Apply an envelope to a value
163 */
164static int apply_envelope(struct ml_effect_state *state, int value,
165 struct ff_envelope *envelope)
166{
167 struct ff_effect *effect = state->effect;
168 unsigned long now = jiffies;
169 int time_from_level;
170 int time_of_envelope;
171 int envelope_level;
172 int difference;
173
174 if (envelope->attack_length &&
175 time_before(now,
176 state->play_at + msecs_to_jiffies(envelope->attack_length))) {
177 pr_debug("value = 0x%x, attack_level = 0x%x\n",
178 value, envelope->attack_level);
179 time_from_level = jiffies_to_msecs(now - state->play_at);
180 time_of_envelope = envelope->attack_length;
181 envelope_level = min_t(u16, envelope->attack_level, 0x7fff);
182
183 } else if (envelope->fade_length && effect->replay.length &&
184 time_after(now,
185 state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
186 time_before(now, state->stop_at)) {
187 time_from_level = jiffies_to_msecs(state->stop_at - now);
188 time_of_envelope = envelope->fade_length;
189 envelope_level = min_t(u16, envelope->fade_level, 0x7fff);
190 } else
191 return value;
192
193 difference = abs(value) - envelope_level;
194
195 pr_debug("difference = %d\n", difference);
196 pr_debug("time_from_level = 0x%x\n", time_from_level);
197 pr_debug("time_of_envelope = 0x%x\n", time_of_envelope);
198
199 difference = difference * time_from_level / time_of_envelope;
200
201 pr_debug("difference = %d\n", difference);
202
203 return value < 0 ?
204 -(difference + envelope_level) : (difference + envelope_level);
205}
206
207/*
208 * Return the type the effect has to be converted into (memless devices)
209 */
210static int get_compatible_type(struct ff_device *ff, int effect_type)
211{
212
213 if (test_bit(effect_type, ff->ffbit))
214 return effect_type;
215
216 if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
217 return FF_RUMBLE;
218
219 pr_err("invalid type in get_compatible_type()\n");
220
221 return 0;
222}
223
224/*
225 * Only left/right direction should be used (under/over 0x8000) for
226 * forward/reverse motor direction (to keep calculation fast & simple).
227 */
228static u16 ml_calculate_direction(u16 direction, u16 force,
229 u16 new_direction, u16 new_force)
230{
231 if (!force)
232 return new_direction;
233 if (!new_force)
234 return direction;
235 return (((u32)(direction >> 1) * force +
236 (new_direction >> 1) * new_force) /
237 (force + new_force)) << 1;
238}
239
240#define FRAC_N 8
241static inline s16 fixp_new16(s16 a)
242{
243 return ((s32)a) >> (16 - FRAC_N);
244}
245
246static inline s16 fixp_mult(s16 a, s16 b)
247{
248 a = ((s32)a * 0x100) / 0x7fff;
249 return ((s32)(a * b)) >> FRAC_N;
250}
251
252/*
253 * Combine two effects and apply gain.
254 */
255static void ml_combine_effects(struct ff_effect *effect,
256 struct ml_effect_state *state,
257 int gain)
258{
259 struct ff_effect *new = state->effect;
260 unsigned int strong, weak, i;
261 int x, y;
262 s16 level;
263
264 switch (new->type) {
265 case FF_CONSTANT:
266 i = new->direction * 360 / 0xffff;
267 level = fixp_new16(apply_envelope(state,
268 new->u.constant.level,
269 &new->u.constant.envelope));
270 x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff;
271 y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff;
272 /*
273 * here we abuse ff_ramp to hold x and y of constant force
274 * If in future any driver wants something else than x and y
275 * in s8, this should be changed to something more generic
276 */
277 effect->u.ramp.start_level =
278 clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
279 effect->u.ramp.end_level =
280 clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
281 break;
282
283 case FF_RUMBLE:
284 strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
285 weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
286
287 if (effect->u.rumble.strong_magnitude + strong)
288 effect->direction = ml_calculate_direction(
289 effect->direction,
290 effect->u.rumble.strong_magnitude,
291 new->direction, strong);
292 else if (effect->u.rumble.weak_magnitude + weak)
293 effect->direction = ml_calculate_direction(
294 effect->direction,
295 effect->u.rumble.weak_magnitude,
296 new->direction, weak);
297 else
298 effect->direction = 0;
299 effect->u.rumble.strong_magnitude =
300 min(strong + effect->u.rumble.strong_magnitude,
301 0xffffU);
302 effect->u.rumble.weak_magnitude =
303 min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
304 break;
305
306 case FF_PERIODIC:
307 i = apply_envelope(state, abs(new->u.periodic.magnitude),
308 &new->u.periodic.envelope);
309
310 /* here we also scale it 0x7fff => 0xffff */
311 i = i * gain / 0x7fff;
312
313 if (effect->u.rumble.strong_magnitude + i)
314 effect->direction = ml_calculate_direction(
315 effect->direction,
316 effect->u.rumble.strong_magnitude,
317 new->direction, i);
318 else
319 effect->direction = 0;
320 effect->u.rumble.strong_magnitude =
321 min(i + effect->u.rumble.strong_magnitude, 0xffffU);
322 effect->u.rumble.weak_magnitude =
323 min(i + effect->u.rumble.weak_magnitude, 0xffffU);
324 break;
325
326 default:
327 pr_err("invalid type in ml_combine_effects()\n");
328 break;
329 }
330
331}
332
333
334/*
335 * Because memoryless devices have only one effect per effect type active
336 * at one time we have to combine multiple effects into one
337 */
338static int ml_get_combo_effect(struct ml_device *ml,
339 unsigned long *effect_handled,
340 struct ff_effect *combo_effect)
341{
342 struct ff_effect *effect;
343 struct ml_effect_state *state;
344 int effect_type;
345 int i;
346
347 memset(combo_effect, 0, sizeof(struct ff_effect));
348
349 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
350 if (__test_and_set_bit(i, effect_handled))
351 continue;
352
353 state = &ml->states[i];
354 effect = state->effect;
355
356 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
357 continue;
358
359 if (time_before(jiffies, state->play_at))
360 continue;
361
362 /*
363 * here we have started effects that are either
364 * currently playing (and may need be aborted)
365 * or need to start playing.
366 */
367 effect_type = get_compatible_type(ml->dev->ff, effect->type);
368 if (combo_effect->type != effect_type) {
369 if (combo_effect->type != 0) {
370 __clear_bit(i, effect_handled);
371 continue;
372 }
373 combo_effect->type = effect_type;
374 }
375
376 if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
377 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
378 __clear_bit(FF_EFFECT_STARTED, &state->flags);
379 } else if (effect->replay.length &&
380 time_after_eq(jiffies, state->stop_at)) {
381
382 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
383
384 if (--state->count <= 0) {
385 __clear_bit(FF_EFFECT_STARTED, &state->flags);
386 } else {
387 state->play_at = jiffies +
388 msecs_to_jiffies(effect->replay.delay);
389 state->stop_at = state->play_at +
390 msecs_to_jiffies(effect->replay.length);
391 }
392 } else {
393 __set_bit(FF_EFFECT_PLAYING, &state->flags);
394 state->adj_at = jiffies;
395 ml_combine_effects(combo_effect, state, ml->gain);
396 }
397 }
398
399 return combo_effect->type != 0;
400}
401
402static void ml_play_effects(struct ml_device *ml)
403{
404 struct ff_effect effect;
405 DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
406
407 memset(handled_bm, 0, sizeof(handled_bm));
408
409 while (ml_get_combo_effect(ml, handled_bm, &effect))
410 ml->play_effect(ml->dev, ml->private, &effect);
411
412 ml_schedule_timer(ml);
413}
414
415static void ml_effect_timer(unsigned long timer_data)
416{
417 struct input_dev *dev = (struct input_dev *)timer_data;
418 struct ml_device *ml = dev->ff->private;
419 unsigned long flags;
420
421 pr_debug("timer: updating effects\n");
422
423 spin_lock_irqsave(&dev->event_lock, flags);
424 ml_play_effects(ml);
425 spin_unlock_irqrestore(&dev->event_lock, flags);
426}
427
428/*
429 * Sets requested gain for FF effects. Called with dev->event_lock held.
430 */
431static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
432{
433 struct ml_device *ml = dev->ff->private;
434 int i;
435
436 ml->gain = gain;
437
438 for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
439 __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
440
441 ml_play_effects(ml);
442}
443
444/*
445 * Start/stop specified FF effect. Called with dev->event_lock held.
446 */
447static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
448{
449 struct ml_device *ml = dev->ff->private;
450 struct ml_effect_state *state = &ml->states[effect_id];
451
452 if (value > 0) {
453 pr_debug("initiated play\n");
454
455 __set_bit(FF_EFFECT_STARTED, &state->flags);
456 state->count = value;
457 state->play_at = jiffies +
458 msecs_to_jiffies(state->effect->replay.delay);
459 state->stop_at = state->play_at +
460 msecs_to_jiffies(state->effect->replay.length);
461 state->adj_at = state->play_at;
462
463 } else {
464 pr_debug("initiated stop\n");
465
466 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
467 __set_bit(FF_EFFECT_ABORTING, &state->flags);
468 else
469 __clear_bit(FF_EFFECT_STARTED, &state->flags);
470 }
471
472 ml_play_effects(ml);
473
474 return 0;
475}
476
477static int ml_ff_upload(struct input_dev *dev,
478 struct ff_effect *effect, struct ff_effect *old)
479{
480 struct ml_device *ml = dev->ff->private;
481 struct ml_effect_state *state = &ml->states[effect->id];
482
483 spin_lock_irq(&dev->event_lock);
484
485 if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
486 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
487 state->play_at = jiffies +
488 msecs_to_jiffies(state->effect->replay.delay);
489 state->stop_at = state->play_at +
490 msecs_to_jiffies(state->effect->replay.length);
491 state->adj_at = state->play_at;
492 ml_schedule_timer(ml);
493 }
494
495 spin_unlock_irq(&dev->event_lock);
496
497 return 0;
498}
499
500static void ml_ff_destroy(struct ff_device *ff)
501{
502 struct ml_device *ml = ff->private;
503
504 kfree(ml->private);
505}
506
507/**
508 * input_ff_create_memless() - create memoryless force-feedback device
509 * @dev: input device supporting force-feedback
510 * @data: driver-specific data to be passed into @play_effect
511 * @play_effect: driver-specific method for playing FF effect
512 */
513int input_ff_create_memless(struct input_dev *dev, void *data,
514 int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
515{
516 struct ml_device *ml;
517 struct ff_device *ff;
518 int error;
519 int i;
520
521 ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
522 if (!ml)
523 return -ENOMEM;
524
525 ml->dev = dev;
526 ml->private = data;
527 ml->play_effect = play_effect;
528 ml->gain = 0xffff;
529 setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
530
531 set_bit(FF_GAIN, dev->ffbit);
532
533 error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
534 if (error) {
535 kfree(ml);
536 return error;
537 }
538
539 ff = dev->ff;
540 ff->private = ml;
541 ff->upload = ml_ff_upload;
542 ff->playback = ml_ff_playback;
543 ff->set_gain = ml_ff_set_gain;
544 ff->destroy = ml_ff_destroy;
545
546 /* we can emulate periodic effects with RUMBLE */
547 if (test_bit(FF_RUMBLE, ff->ffbit)) {
548 set_bit(FF_PERIODIC, dev->ffbit);
549 set_bit(FF_SINE, dev->ffbit);
550 set_bit(FF_TRIANGLE, dev->ffbit);
551 set_bit(FF_SQUARE, dev->ffbit);
552 }
553
554 for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
555 ml->states[i].effect = &ff->effects[i];
556
557 return 0;
558}
559EXPORT_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/*
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);