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 /*
 241  * Combine two effects and apply gain.
 242  */
 243 static 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         fixp_t 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_sin(i), level) * gain / 0xffff;
 259                 y = fixp_mult(-fixp_cos(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  */
 326 static 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
 390 static 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
 403 static void ml_effect_timer(unsigned long timer_data)
 404 {
 405         struct input_dev *dev = (struct input_dev *)timer_data;
 406         struct ml_device *ml = dev->ff->private;
 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  */
 419 static 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  */
 435 static 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
 465 static 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
 488 static void ml_ff_destroy(struct ff_device *ff)
 489 {
 490         struct ml_device *ml = ff->private;
 491
 492         kfree(ml->private);
 493 }
 494
 495 /**
 496  * input_ff_create_memless() - create memoryless force-feedback device
 497  * @dev: input device supporting force-feedback
 498  * @data: driver-specific data to be passed into @play_effect
 499  * @play_effect: driver-specific method for playing FF effect
 500  */
 501 int input_ff_create_memless(struct input_dev *dev, void *data,
 502                 int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
 503 {
 504         struct ml_device *ml;
 505         struct ff_device *ff;
 506         int error;
 507         int i;
 508
 509         ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
 510         if (!ml)
 511                 return -ENOMEM;
 512
 513         ml->dev = dev;
 514         ml->private = data;
 515         ml->play_effect = play_effect;
 516         ml->gain = 0xffff;
 517         setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
 518
 519         set_bit(FF_GAIN, dev->ffbit);
 520
 521         error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
 522         if (error) {
 523                 kfree(ml);
 524                 return error;
 525         }
 526
 527         ff = dev->ff;
 528         ff->private = ml;
 529         ff->upload = ml_ff_upload;
 530         ff->playback = ml_ff_playback;
 531         ff->set_gain = ml_ff_set_gain;
 532         ff->destroy = ml_ff_destroy;
 533
 534         /* we can emulate periodic effects with RUMBLE */
 535         if (test_bit(FF_RUMBLE, ff->ffbit)) {
 536                 set_bit(FF_PERIODIC, dev->ffbit);
 537                 set_bit(FF_SINE, dev->ffbit);
 538                 set_bit(FF_TRIANGLE, dev->ffbit);
 539                 set_bit(FF_SQUARE, dev->ffbit);
 540         }
 541
 542         for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
 543                 ml->states[i].effect = &ff->effects[i];
 544
 545         return 0;
 546 }
 547 EXPORT_SYMBOL_GPL(input_ff_create_memless);