2 * Force feedback support for memoryless devices
4 * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
5 * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
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.
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.
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
26 #define debug(format, arg...) pr_debug("ff-memless: " format "\n", ## arg)
28 #include <linux/input.h>
29 #include <linux/module.h>
30 #include <linux/mutex.h>
31 #include <linux/spinlock.h>
32 #include <linux/sched.h>
34 #include "fixp-arith.h"
36 MODULE_LICENSE("GPL");
37 MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
38 MODULE_DESCRIPTION("Force feedback support for memoryless devices");
40 /* Number of effects handled with memoryless devices */
41 #define FF_MEMLESS_EFFECTS 16
43 /* Envelope update interval in ms */
44 #define FF_ENVELOPE_INTERVAL 50
46 #define FF_EFFECT_STARTED 0
47 #define FF_EFFECT_PLAYING 1
48 #define FF_EFFECT_ABORTING 2
50 struct 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 */
61 struct ml_effect_state states[FF_MEMLESS_EFFECTS];
63 struct timer_list timer;
64 spinlock_t timer_lock;
65 struct input_dev *dev;
67 int (*play_effect)(struct input_dev *dev, void *data,
68 struct ff_effect *effect);
71 static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
73 static const struct ff_envelope empty_envelope;
75 switch (effect->type) {
77 return &effect->u.periodic.envelope;
79 return &effect->u.constant.envelope;
81 return &empty_envelope;
86 * Check for the next time envelope requires an update on memoryless devices
88 static unsigned long calculate_next_time(struct ml_effect_state *state)
90 const struct ff_envelope *envelope = get_envelope(state->effect);
91 unsigned long attack_stop, fade_start, next_fade;
93 if (envelope->attack_length) {
94 attack_stop = state->play_at +
95 msecs_to_jiffies(envelope->attack_length);
96 if (time_before(state->adj_at, attack_stop))
97 return state->adj_at +
98 msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
101 if (state->effect->replay.length) {
102 if (envelope->fade_length) {
103 /* check when fading should start */
104 fade_start = state->stop_at -
105 msecs_to_jiffies(envelope->fade_length);
107 if (time_before(state->adj_at, fade_start))
110 /* already fading, advance to next checkpoint */
111 next_fade = state->adj_at +
112 msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
113 if (time_before(next_fade, state->stop_at))
117 return state->stop_at;
120 return state->play_at;
123 static void ml_schedule_timer(struct ml_device *ml)
125 struct ml_effect_state *state;
126 unsigned long now = jiffies;
127 unsigned long earliest = 0;
128 unsigned long next_at;
132 debug("calculating next timer");
134 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
136 state = &ml->states[i];
138 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
141 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
142 next_at = calculate_next_time(state);
144 next_at = state->play_at;
146 if (time_before_eq(now, next_at) &&
147 (++events == 1 || time_before(next_at, earliest)))
153 del_timer(&ml->timer);
156 mod_timer(&ml->timer, earliest);
161 * Apply an envelope to a value
163 static int apply_envelope(struct ml_effect_state *state, int value,
164 struct ff_envelope *envelope)
166 struct ff_effect *effect = state->effect;
167 unsigned long now = jiffies;
169 int time_of_envelope;
173 if (envelope->attack_length &&
175 state->play_at + msecs_to_jiffies(envelope->attack_length))) {
176 debug("value = 0x%x, attack_level = 0x%x", value,
177 envelope->attack_level);
178 time_from_level = jiffies_to_msecs(now - state->play_at);
179 time_of_envelope = envelope->attack_length;
180 envelope_level = min_t(__s16, envelope->attack_level, 0x7fff);
182 } else if (envelope->fade_length && effect->replay.length &&
184 state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
185 time_before(now, state->stop_at)) {
186 time_from_level = jiffies_to_msecs(state->stop_at - now);
187 time_of_envelope = envelope->fade_length;
188 envelope_level = min_t(__s16, envelope->fade_level, 0x7fff);
192 difference = abs(value) - envelope_level;
194 debug("difference = %d", difference);
195 debug("time_from_level = 0x%x", time_from_level);
196 debug("time_of_envelope = 0x%x", time_of_envelope);
198 difference = difference * time_from_level / time_of_envelope;
200 debug("difference = %d", difference);
203 -(difference + envelope_level) : (difference + envelope_level);
207 * Return the type the effect has to be converted into (memless devices)
209 static int get_compatible_type(struct ff_device *ff, int effect_type)
212 if (test_bit(effect_type, ff->ffbit))
215 if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
219 "ff-memless: invalid type in get_compatible_type()\n");
225 * Combine two effects and apply gain.
227 static void ml_combine_effects(struct ff_effect *effect,
228 struct ml_effect_state *state,
231 struct ff_effect *new = state->effect;
232 unsigned int strong, weak, i;
238 i = new->direction * 360 / 0xffff;
239 level = fixp_new16(apply_envelope(state,
240 new->u.constant.level,
241 &new->u.constant.envelope));
242 x = fixp_mult(fixp_sin(i), level) * gain / 0xffff;
243 y = fixp_mult(-fixp_cos(i), level) * gain / 0xffff;
245 * here we abuse ff_ramp to hold x and y of constant force
246 * If in future any driver wants something else than x and y
247 * in s8, this should be changed to something more generic
249 effect->u.ramp.start_level =
250 max(min(effect->u.ramp.start_level + x, 0x7f), -0x80);
251 effect->u.ramp.end_level =
252 max(min(effect->u.ramp.end_level + y, 0x7f), -0x80);
256 strong = new->u.rumble.strong_magnitude * gain / 0xffff;
257 weak = new->u.rumble.weak_magnitude * gain / 0xffff;
258 effect->u.rumble.strong_magnitude =
259 min(strong + effect->u.rumble.strong_magnitude,
261 effect->u.rumble.weak_magnitude =
262 min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
266 i = apply_envelope(state, abs(new->u.periodic.magnitude),
267 &new->u.periodic.envelope);
269 /* here we also scale it 0x7fff => 0xffff */
270 i = i * gain / 0x7fff;
272 effect->u.rumble.strong_magnitude =
273 min(i + effect->u.rumble.strong_magnitude, 0xffffU);
274 effect->u.rumble.weak_magnitude =
275 min(i + effect->u.rumble.weak_magnitude, 0xffffU);
279 printk(KERN_ERR "ff-memless: invalid type in ml_combine_effects()\n");
287 * Because memoryless devices have only one effect per effect type active
288 * at one time we have to combine multiple effects into one
290 static int ml_get_combo_effect(struct ml_device *ml,
291 unsigned long *effect_handled,
292 struct ff_effect *combo_effect)
294 struct ff_effect *effect;
295 struct ml_effect_state *state;
299 memset(combo_effect, 0, sizeof(struct ff_effect));
301 for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
302 if (__test_and_set_bit(i, effect_handled))
305 state = &ml->states[i];
306 effect = state->effect;
308 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
311 if (time_before(jiffies, state->play_at))
315 * here we have started effects that are either
316 * currently playing (and may need be aborted)
317 * or need to start playing.
319 effect_type = get_compatible_type(ml->dev->ff, effect->type);
320 if (combo_effect->type != effect_type) {
321 if (combo_effect->type != 0) {
322 __clear_bit(i, effect_handled);
325 combo_effect->type = effect_type;
328 if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
329 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
330 __clear_bit(FF_EFFECT_STARTED, &state->flags);
331 } else if (effect->replay.length &&
332 time_after_eq(jiffies, state->stop_at)) {
334 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
336 if (--state->count <= 0) {
337 __clear_bit(FF_EFFECT_STARTED, &state->flags);
339 state->play_at = jiffies +
340 msecs_to_jiffies(effect->replay.delay);
341 state->stop_at = state->play_at +
342 msecs_to_jiffies(effect->replay.length);
345 __set_bit(FF_EFFECT_PLAYING, &state->flags);
346 state->adj_at = jiffies;
347 ml_combine_effects(combo_effect, state, ml->gain);
351 return combo_effect->type != 0;
354 static void ml_play_effects(struct ml_device *ml)
356 struct ff_effect effect;
357 DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
359 memset(handled_bm, 0, sizeof(handled_bm));
361 while (ml_get_combo_effect(ml, handled_bm, &effect))
362 ml->play_effect(ml->dev, ml->private, &effect);
364 ml_schedule_timer(ml);
367 static void ml_effect_timer(unsigned long timer_data)
369 struct input_dev *dev = (struct input_dev *)timer_data;
370 struct ml_device *ml = dev->ff->private;
372 debug("timer: updating effects");
374 spin_lock(&ml->timer_lock);
376 spin_unlock(&ml->timer_lock);
379 static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
381 struct ml_device *ml = dev->ff->private;
384 spin_lock_bh(&ml->timer_lock);
388 for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
389 __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
393 spin_unlock_bh(&ml->timer_lock);
396 static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
398 struct ml_device *ml = dev->ff->private;
399 struct ml_effect_state *state = &ml->states[effect_id];
401 spin_lock_bh(&ml->timer_lock);
404 debug("initiated play");
406 __set_bit(FF_EFFECT_STARTED, &state->flags);
407 state->count = value;
408 state->play_at = jiffies +
409 msecs_to_jiffies(state->effect->replay.delay);
410 state->stop_at = state->play_at +
411 msecs_to_jiffies(state->effect->replay.length);
412 state->adj_at = state->play_at;
414 ml_schedule_timer(ml);
417 debug("initiated stop");
419 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
420 __set_bit(FF_EFFECT_ABORTING, &state->flags);
422 __clear_bit(FF_EFFECT_STARTED, &state->flags);
427 spin_unlock_bh(&ml->timer_lock);
432 static int ml_ff_upload(struct input_dev *dev,
433 struct ff_effect *effect, struct ff_effect *old)
435 struct ml_device *ml = dev->ff->private;
436 struct ml_effect_state *state = &ml->states[effect->id];
438 spin_lock_bh(&ml->timer_lock);
440 if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
441 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
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 ml_schedule_timer(ml);
450 spin_unlock_bh(&ml->timer_lock);
455 static void ml_ff_destroy(struct ff_device *ff)
457 struct ml_device *ml = ff->private;
463 * input_ff_create_memless() - create memoryless force-feedback device
464 * @dev: input device supporting force-feedback
465 * @data: driver-specific data to be passed into @play_effect
466 * @play_effect: driver-specific method for playing FF effect
468 int input_ff_create_memless(struct input_dev *dev, void *data,
469 int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
471 struct ml_device *ml;
472 struct ff_device *ff;
476 ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
482 ml->play_effect = play_effect;
484 spin_lock_init(&ml->timer_lock);
485 setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
487 set_bit(FF_GAIN, dev->ffbit);
489 error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
497 ff->upload = ml_ff_upload;
498 ff->playback = ml_ff_playback;
499 ff->set_gain = ml_ff_set_gain;
500 ff->destroy = ml_ff_destroy;
502 /* we can emulate periodic effects with RUMBLE */
503 if (test_bit(FF_RUMBLE, ff->ffbit)) {
504 set_bit(FF_PERIODIC, dev->ffbit);
505 set_bit(FF_SINE, dev->ffbit);
506 set_bit(FF_TRIANGLE, dev->ffbit);
507 set_bit(FF_SQUARE, dev->ffbit);
510 for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
511 ml->states[i].effect = &ff->effects[i];
515 EXPORT_SYMBOL_GPL(input_ff_create_memless);