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
  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  */
  89 static 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
 124 static 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  */
 164 static 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  */
 210 static 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  */
 228 static 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
 241 static inline s16 fixp_new16(s16 a)
 242 {
 243         return ((s32)a) >> (16 - FRAC_N);
 244 }
 245
 246 static 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  */
 255 static 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  */
 338 static 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
 402 static 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
 415 static void ml_effect_timer(struct timer_list *t)
 416 {
 417         struct ml_device *ml = from_timer(ml, t, timer);
 418         struct input_dev *dev = ml->dev;
 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  */
 431 static 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  */
 447 static 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
 477 static 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
 500 static 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  */
 513 int 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         timer_setup(&ml->timer, ml_effect_timer, 0);
 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 }
 559 EXPORT_SYMBOL_GPL(input_ff_create_memless);