drivers/input/ff-memless.c

   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
  36 MODULE_LICENSE("GPL");
  37 MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
  38 MODULE_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
  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 */
  57 };
  58
  59 struct 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
  70 static 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  */
  87 static 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
 122 static 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  */
 162 static 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  */
 208 static 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  */
 226 static 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  */
 241 static 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  */
 324 static 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
 388 static 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
 401 static 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  */
 417 static 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  */
 433 static 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
 463 static 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
 486 static 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  */
 499 int 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 }
 545 EXPORT_SYMBOL_GPL(input_ff_create_memless);