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
  35 #include "fixp-arith.h"
  36
  37 MODULE_LICENSE("GPL");
  38 MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
  39 MODULE_DESCRIPTION("Force feedback support for memoryless devices");
  40
  41 /* Number of effects handled with memoryless devices */
  42 #define FF_MEMLESS_EFFECTS      16
  43
  44 /* Envelope update interval in ms */
  45 #define FF_ENVELOPE_INTERVAL    50
  46
  47 #define FF_EFFECT_STARTED       0
  48 #define FF_EFFECT_PLAYING       1
  49 #define FF_EFFECT_ABORTING      2
  50
  51 struct ml_effect_state {
  52         struct ff_effect *effect;
  53         unsigned long flags;    /* effect state (STARTED, PLAYING, etc) */
  54         int count;              /* loop count of the effect */
  55         unsigned long play_at;  /* start time */
  56         unsigned long stop_at;  /* stop time */
  57         unsigned long adj_at;   /* last time the effect was sent */
  58 };
  59
  60 struct ml_device {
  61         void *private;
  62         struct ml_effect_state states[FF_MEMLESS_EFFECTS];
  63         int gain;
  64         struct timer_list timer;
  65         struct input_dev *dev;
  66
  67         int (*play_effect)(struct input_dev *dev, void *data,
  68                            struct ff_effect *effect);
  69 };
  70
  71 static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
  72 {
  73         static const struct ff_envelope empty_envelope;
  74
  75         switch (effect->type) {
  76                 case FF_PERIODIC:
  77                         return &effect->u.periodic.envelope;
  78                 case FF_CONSTANT:
  79                         return &effect->u.constant.envelope;
  80                 default:
  81                         return &empty_envelope;
  82         }
  83 }
  84
  85 /*
  86  * Check for the next time envelope requires an update on memoryless devices
  87  */
  88 static unsigned long calculate_next_time(struct ml_effect_state *state)
  89 {
  90         const struct ff_envelope *envelope = get_envelope(state->effect);
  91         unsigned long attack_stop, fade_start, next_fade;
  92
  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);
  99         }
 100
 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);
 106
 107                         if (time_before(state->adj_at, fade_start))
 108                                 return fade_start;
 109
 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))
 114                                 return next_fade;
 115                 }
 116
 117                 return state->stop_at;
 118         }
 119
 120         return state->play_at;
 121 }
 122
 123 static void ml_schedule_timer(struct ml_device *ml)
 124 {
 125         struct ml_effect_state *state;
 126         unsigned long now = jiffies;
 127         unsigned long earliest = 0;
 128         unsigned long next_at;
 129         int events = 0;
 130         int i;
 131
 132         pr_debug("calculating next timer\n");
 133
 134         for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
 135
 136                 state = &ml->states[i];
 137
 138                 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
 139                         continue;
 140
 141                 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
 142                         next_at = calculate_next_time(state);
 143                 else
 144                         next_at = state->play_at;
 145
 146                 if (time_before_eq(now, next_at) &&
 147                     (++events == 1 || time_before(next_at, earliest)))
 148                         earliest = next_at;
 149         }
 150
 151         if (!events) {
 152                 pr_debug("no actions\n");
 153                 del_timer(&ml->timer);
 154         } else {
 155                 pr_debug("timer set\n");
 156                 mod_timer(&ml->timer, earliest);
 157         }
 158 }
 159
 160 /*
 161  * Apply an envelope to a value
 162  */
 163 static int apply_envelope(struct ml_effect_state *state, int value,
 164                           struct ff_envelope *envelope)
 165 {
 166         struct ff_effect *effect = state->effect;
 167         unsigned long now = jiffies;
 168         int time_from_level;
 169         int time_of_envelope;
 170         int envelope_level;
 171         int difference;
 172
 173         if (envelope->attack_length &&
 174             time_before(now,
 175                         state->play_at + msecs_to_jiffies(envelope->attack_length))) {
 176                 pr_debug("value = 0x%x, attack_level = 0x%x\n",
 177                          value, 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);
 181
 182         } else if (envelope->fade_length && effect->replay.length &&
 183                    time_after(now,
 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);
 189         } else
 190                 return value;
 191
 192         difference = abs(value) - envelope_level;
 193
 194         pr_debug("difference = %d\n", difference);
 195         pr_debug("time_from_level = 0x%x\n", time_from_level);
 196         pr_debug("time_of_envelope = 0x%x\n", time_of_envelope);
 197
 198         difference = difference * time_from_level / time_of_envelope;
 199
 200         pr_debug("difference = %d\n", difference);
 201
 202         return value < 0 ?
 203                 -(difference + envelope_level) : (difference + envelope_level);
 204 }
 205
 206 /*
 207  * Return the type the effect has to be converted into (memless devices)
 208  */
 209 static int get_compatible_type(struct ff_device *ff, int effect_type)
 210 {
 211
 212         if (test_bit(effect_type, ff->ffbit))
 213                 return effect_type;
 214
 215         if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
 216                 return FF_RUMBLE;
 217
 218         pr_err("invalid type in get_compatible_type()\n");
 219
 220         return 0;
 221 }
 222
 223 /*
 224  * Only left/right direction should be used (under/over 0x8000) for
 225  * forward/reverse motor direction (to keep calculation fast & simple).
 226  */
 227 static u16 ml_calculate_direction(u16 direction, u16 force,
 228                                   u16 new_direction, u16 new_force)
 229 {
 230         if (!force)
 231                 return new_direction;
 232         if (!new_force)
 233                 return direction;
 234         return (((u32)(direction >> 1) * force +
 235                  (new_direction >> 1) * new_force) /
 236                 (force + new_force)) << 1;
 237 }
 238
 239 /*
 240  * Combine two effects and apply gain.
 241  */
 242 static void ml_combine_effects(struct ff_effect *effect,
 243                                struct ml_effect_state *state,
 244                                int gain)
 245 {
 246         struct ff_effect *new = state->effect;
 247         unsigned int strong, weak, i;
 248         int x, y;
 249         fixp_t level;
 250
 251         switch (new->type) {
 252         case FF_CONSTANT:
 253                 i = new->direction * 360 / 0xffff;
 254                 level = fixp_new16(apply_envelope(state,
 255                                         new->u.constant.level,
 256                                         &new->u.constant.envelope));
 257                 x = fixp_mult(fixp_sin(i), level) * gain / 0xffff;
 258                 y = fixp_mult(-fixp_cos(i), level) * gain / 0xffff;
 259                 /*
 260                  * here we abuse ff_ramp to hold x and y of constant force
 261                  * If in future any driver wants something else than x and y
 262                  * in s8, this should be changed to something more generic
 263                  */
 264                 effect->u.ramp.start_level =
 265                         clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
 266                 effect->u.ramp.end_level =
 267                         clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
 268                 break;
 269
 270         case FF_RUMBLE:
 271                 strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
 272                 weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
 273
 274                 if (effect->u.rumble.strong_magnitude + strong)
 275                         effect->direction = ml_calculate_direction(
 276                                 effect->direction,
 277                                 effect->u.rumble.strong_magnitude,
 278                                 new->direction, strong);
 279                 else if (effect->u.rumble.weak_magnitude + weak)
 280                         effect->direction = ml_calculate_direction(
 281                                 effect->direction,
 282                                 effect->u.rumble.weak_magnitude,
 283                                 new->direction, weak);
 284                 else
 285                         effect->direction = 0;
 286                 effect->u.rumble.strong_magnitude =
 287                         min(strong + effect->u.rumble.strong_magnitude,
 288                             0xffffU);
 289                 effect->u.rumble.weak_magnitude =
 290                         min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
 291                 break;
 292
 293         case FF_PERIODIC:
 294                 i = apply_envelope(state, abs(new->u.periodic.magnitude),
 295                                    &new->u.periodic.envelope);
 296
 297                 /* here we also scale it 0x7fff => 0xffff */
 298                 i = i * gain / 0x7fff;
 299
 300                 if (effect->u.rumble.strong_magnitude + i)
 301                         effect->direction = ml_calculate_direction(
 302                                 effect->direction,
 303                                 effect->u.rumble.strong_magnitude,
 304                                 new->direction, i);
 305                 else
 306                         effect->direction = 0;
 307                 effect->u.rumble.strong_magnitude =
 308                         min(i + effect->u.rumble.strong_magnitude, 0xffffU);
 309                 effect->u.rumble.weak_magnitude =
 310                         min(i + effect->u.rumble.weak_magnitude, 0xffffU);
 311                 break;
 312
 313         default:
 314                 pr_err("invalid type in ml_combine_effects()\n");
 315                 break;
 316         }
 317
 318 }
 319
 320
 321 /*
 322  * Because memoryless devices have only one effect per effect type active
 323  * at one time we have to combine multiple effects into one
 324  */
 325 static int ml_get_combo_effect(struct ml_device *ml,
 326                                unsigned long *effect_handled,
 327                                struct ff_effect *combo_effect)
 328 {
 329         struct ff_effect *effect;
 330         struct ml_effect_state *state;
 331         int effect_type;
 332         int i;
 333
 334         memset(combo_effect, 0, sizeof(struct ff_effect));
 335
 336         for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
 337                 if (__test_and_set_bit(i, effect_handled))
 338                         continue;
 339
 340                 state = &ml->states[i];
 341                 effect = state->effect;
 342
 343                 if (!test_bit(FF_EFFECT_STARTED, &state->flags))
 344                         continue;
 345
 346                 if (time_before(jiffies, state->play_at))
 347                         continue;
 348
 349                 /*
 350                  * here we have started effects that are either
 351                  * currently playing (and may need be aborted)
 352                  * or need to start playing.
 353                  */
 354                 effect_type = get_compatible_type(ml->dev->ff, effect->type);
 355                 if (combo_effect->type != effect_type) {
 356                         if (combo_effect->type != 0) {
 357                                 __clear_bit(i, effect_handled);
 358                                 continue;
 359                         }
 360                         combo_effect->type = effect_type;
 361                 }
 362
 363                 if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
 364                         __clear_bit(FF_EFFECT_PLAYING, &state->flags);
 365                         __clear_bit(FF_EFFECT_STARTED, &state->flags);
 366                 } else if (effect->replay.length &&
 367                            time_after_eq(jiffies, state->stop_at)) {
 368
 369                         __clear_bit(FF_EFFECT_PLAYING, &state->flags);
 370
 371                         if (--state->count <= 0) {
 372                                 __clear_bit(FF_EFFECT_STARTED, &state->flags);
 373                         } else {
 374                                 state->play_at = jiffies +
 375                                         msecs_to_jiffies(effect->replay.delay);
 376                                 state->stop_at = state->play_at +
 377                                         msecs_to_jiffies(effect->replay.length);
 378                         }
 379                 } else {
 380                         __set_bit(FF_EFFECT_PLAYING, &state->flags);
 381                         state->adj_at = jiffies;
 382                         ml_combine_effects(combo_effect, state, ml->gain);
 383                 }
 384         }
 385
 386         return combo_effect->type != 0;
 387 }
 388
 389 static void ml_play_effects(struct ml_device *ml)
 390 {
 391         struct ff_effect effect;
 392         DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
 393
 394         memset(handled_bm, 0, sizeof(handled_bm));
 395
 396         while (ml_get_combo_effect(ml, handled_bm, &effect))
 397                 ml->play_effect(ml->dev, ml->private, &effect);
 398
 399         ml_schedule_timer(ml);
 400 }
 401
 402 static void ml_effect_timer(unsigned long timer_data)
 403 {
 404         struct input_dev *dev = (struct input_dev *)timer_data;
 405         struct ml_device *ml = dev->ff->private;
 406         unsigned long flags;
 407
 408         pr_debug("timer: updating effects\n");
 409
 410         spin_lock_irqsave(&dev->event_lock, flags);
 411         ml_play_effects(ml);
 412         spin_unlock_irqrestore(&dev->event_lock, flags);
 413 }
 414
 415 /*
 416  * Sets requested gain for FF effects. Called with dev->event_lock held.
 417  */
 418 static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
 419 {
 420         struct ml_device *ml = dev->ff->private;
 421         int i;
 422
 423         ml->gain = gain;
 424
 425         for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
 426                 __clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
 427
 428         ml_play_effects(ml);
 429 }
 430
 431 /*
 432  * Start/stop specified FF effect. Called with dev->event_lock held.
 433  */
 434 static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
 435 {
 436         struct ml_device *ml = dev->ff->private;
 437         struct ml_effect_state *state = &ml->states[effect_id];
 438
 439         if (value > 0) {
 440                 pr_debug("initiated play\n");
 441
 442                 __set_bit(FF_EFFECT_STARTED, &state->flags);
 443                 state->count = value;
 444                 state->play_at = jiffies +
 445                                  msecs_to_jiffies(state->effect->replay.delay);
 446                 state->stop_at = state->play_at +
 447                                  msecs_to_jiffies(state->effect->replay.length);
 448                 state->adj_at = state->play_at;
 449
 450         } else {
 451                 pr_debug("initiated stop\n");
 452
 453                 if (test_bit(FF_EFFECT_PLAYING, &state->flags))
 454                         __set_bit(FF_EFFECT_ABORTING, &state->flags);
 455                 else
 456                         __clear_bit(FF_EFFECT_STARTED, &state->flags);
 457         }
 458
 459         ml_play_effects(ml);
 460
 461         return 0;
 462 }
 463
 464 static int ml_ff_upload(struct input_dev *dev,
 465                         struct ff_effect *effect, struct ff_effect *old)
 466 {
 467         struct ml_device *ml = dev->ff->private;
 468         struct ml_effect_state *state = &ml->states[effect->id];
 469
 470         spin_lock_irq(&dev->event_lock);
 471
 472         if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
 473                 __clear_bit(FF_EFFECT_PLAYING, &state->flags);
 474                 state->play_at = jiffies +
 475                                  msecs_to_jiffies(state->effect->replay.delay);
 476                 state->stop_at = state->play_at +
 477                                  msecs_to_jiffies(state->effect->replay.length);
 478                 state->adj_at = state->play_at;
 479                 ml_schedule_timer(ml);
 480         }
 481
 482         spin_unlock_irq(&dev->event_lock);
 483
 484         return 0;
 485 }
 486
 487 static void ml_ff_destroy(struct ff_device *ff)
 488 {
 489         struct ml_device *ml = ff->private;
 490
 491         kfree(ml->private);
 492 }
 493
 494 /**
 495  * input_ff_create_memless() - create memoryless force-feedback device
 496  * @dev: input device supporting force-feedback
 497  * @data: driver-specific data to be passed into @play_effect
 498  * @play_effect: driver-specific method for playing FF effect
 499  */
 500 int input_ff_create_memless(struct input_dev *dev, void *data,
 501                 int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
 502 {
 503         struct ml_device *ml;
 504         struct ff_device *ff;
 505         int error;
 506         int i;
 507
 508         ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
 509         if (!ml)
 510                 return -ENOMEM;
 511
 512         ml->dev = dev;
 513         ml->private = data;
 514         ml->play_effect = play_effect;
 515         ml->gain = 0xffff;
 516         setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
 517
 518         set_bit(FF_GAIN, dev->ffbit);
 519
 520         error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
 521         if (error) {
 522                 kfree(ml);
 523                 return error;
 524         }
 525
 526         ff = dev->ff;
 527         ff->private = ml;
 528         ff->upload = ml_ff_upload;
 529         ff->playback = ml_ff_playback;
 530         ff->set_gain = ml_ff_set_gain;
 531         ff->destroy = ml_ff_destroy;
 532
 533         /* we can emulate periodic effects with RUMBLE */
 534         if (test_bit(FF_RUMBLE, ff->ffbit)) {
 535                 set_bit(FF_PERIODIC, dev->ffbit);
 536                 set_bit(FF_SINE, dev->ffbit);
 537                 set_bit(FF_TRIANGLE, dev->ffbit);
 538                 set_bit(FF_SQUARE, dev->ffbit);
 539         }
 540
 541         for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
 542                 ml->states[i].effect = &ff->effects[i];
 543
 544         return 0;
 545 }
 546 EXPORT_SYMBOL_GPL(input_ff_create_memless);