linux/drivers/input/ff-memless.c
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   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
  36MODULE_LICENSE("GPL");
  37MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
  38MODULE_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
  50struct 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
  59struct 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
  70static 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 */
  87static 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
 122static 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 */
 162static 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(u16, 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(u16, 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 */
 208static 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 */
 226static 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 */
 241static 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 */
 324static 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
 388static 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
 401static 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 */
 417static 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 */
 433static 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
 463static 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
 486static 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 */
 499int 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}
 545EXPORT_SYMBOL_GPL(input_ff_create_memless);
 546
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