drivers/pwm/core.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Generic pwmlib implementation
   4  *
   5  * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
   6  * Copyright (C) 2011-2012 Avionic Design GmbH
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/module.h>
  11 #include <linux/pwm.h>
  12 #include <linux/radix-tree.h>
  13 #include <linux/list.h>
  14 #include <linux/mutex.h>
  15 #include <linux/err.h>
  16 #include <linux/slab.h>
  17 #include <linux/device.h>
  18 #include <linux/debugfs.h>
  19 #include <linux/seq_file.h>
  20
  21 #include <dt-bindings/pwm/pwm.h>
  22
  23 #define CREATE_TRACE_POINTS
  24 #include <trace/events/pwm.h>
  25
  26 #define MAX_PWMS 1024
  27
  28 static DEFINE_MUTEX(pwm_lookup_lock);
  29 static LIST_HEAD(pwm_lookup_list);
  30 static DEFINE_MUTEX(pwm_lock);
  31 static LIST_HEAD(pwm_chips);
  32 static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
  33 static RADIX_TREE(pwm_tree, GFP_KERNEL);
  34
  35 static struct pwm_device *pwm_to_device(unsigned int pwm)
  36 {
  37         return radix_tree_lookup(&pwm_tree, pwm);
  38 }
  39
  40 static int alloc_pwms(int pwm, unsigned int count)
  41 {
  42         unsigned int from = 0;
  43         unsigned int start;
  44
  45         if (pwm >= MAX_PWMS)
  46                 return -EINVAL;
  47
  48         if (pwm >= 0)
  49                 from = pwm;
  50
  51         start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
  52                                            count, 0);
  53
  54         if (pwm >= 0 && start != pwm)
  55                 return -EEXIST;
  56
  57         if (start + count > MAX_PWMS)
  58                 return -ENOSPC;
  59
  60         return start;
  61 }
  62
  63 static void free_pwms(struct pwm_chip *chip)
  64 {
  65         unsigned int i;
  66
  67         for (i = 0; i < chip->npwm; i++) {
  68                 struct pwm_device *pwm = &chip->pwms[i];
  69
  70                 radix_tree_delete(&pwm_tree, pwm->pwm);
  71         }
  72
  73         bitmap_clear(allocated_pwms, chip->base, chip->npwm);
  74
  75         kfree(chip->pwms);
  76         chip->pwms = NULL;
  77 }
  78
  79 static struct pwm_chip *pwmchip_find_by_name(const char *name)
  80 {
  81         struct pwm_chip *chip;
  82
  83         if (!name)
  84                 return NULL;
  85
  86         mutex_lock(&pwm_lock);
  87
  88         list_for_each_entry(chip, &pwm_chips, list) {
  89                 const char *chip_name = dev_name(chip->dev);
  90
  91                 if (chip_name && strcmp(chip_name, name) == 0) {
  92                         mutex_unlock(&pwm_lock);
  93                         return chip;
  94                 }
  95         }
  96
  97         mutex_unlock(&pwm_lock);
  98
  99         return NULL;
 100 }
 101
 102 static int pwm_device_request(struct pwm_device *pwm, const char *label)
 103 {
 104         int err;
 105
 106         if (test_bit(PWMF_REQUESTED, &pwm->flags))
 107                 return -EBUSY;
 108
 109         if (!try_module_get(pwm->chip->ops->owner))
 110                 return -ENODEV;
 111
 112         if (pwm->chip->ops->request) {
 113                 err = pwm->chip->ops->request(pwm->chip, pwm);
 114                 if (err) {
 115                         module_put(pwm->chip->ops->owner);
 116                         return err;
 117                 }
 118         }
 119
 120         if (pwm->chip->ops->get_state) {
 121                 pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
 122                 trace_pwm_get(pwm, &pwm->state);
 123
 124                 if (IS_ENABLED(CONFIG_PWM_DEBUG))
 125                         pwm->last = pwm->state;
 126         }
 127
 128         set_bit(PWMF_REQUESTED, &pwm->flags);
 129         pwm->label = label;
 130
 131         return 0;
 132 }
 133
 134 struct pwm_device *
 135 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 136 {
 137         struct pwm_device *pwm;
 138
 139         /* check, whether the driver supports a third cell for flags */
 140         if (pc->of_pwm_n_cells < 3)
 141                 return ERR_PTR(-EINVAL);
 142
 143         /* flags in the third cell are optional */
 144         if (args->args_count < 2)
 145                 return ERR_PTR(-EINVAL);
 146
 147         if (args->args[0] >= pc->npwm)
 148                 return ERR_PTR(-EINVAL);
 149
 150         pwm = pwm_request_from_chip(pc, args->args[0], NULL);
 151         if (IS_ERR(pwm))
 152                 return pwm;
 153
 154         pwm->args.period = args->args[1];
 155         pwm->args.polarity = PWM_POLARITY_NORMAL;
 156
 157         if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
 158                 pwm->args.polarity = PWM_POLARITY_INVERSED;
 159
 160         return pwm;
 161 }
 162 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
 163
 164 static struct pwm_device *
 165 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
 166 {
 167         struct pwm_device *pwm;
 168
 169         /* sanity check driver support */
 170         if (pc->of_pwm_n_cells < 2)
 171                 return ERR_PTR(-EINVAL);
 172
 173         /* all cells are required */
 174         if (args->args_count != pc->of_pwm_n_cells)
 175                 return ERR_PTR(-EINVAL);
 176
 177         if (args->args[0] >= pc->npwm)
 178                 return ERR_PTR(-EINVAL);
 179
 180         pwm = pwm_request_from_chip(pc, args->args[0], NULL);
 181         if (IS_ERR(pwm))
 182                 return pwm;
 183
 184         pwm->args.period = args->args[1];
 185
 186         return pwm;
 187 }
 188
 189 static void of_pwmchip_add(struct pwm_chip *chip)
 190 {
 191         if (!chip->dev || !chip->dev->of_node)
 192                 return;
 193
 194         if (!chip->of_xlate) {
 195                 chip->of_xlate = of_pwm_simple_xlate;
 196                 chip->of_pwm_n_cells = 2;
 197         }
 198
 199         of_node_get(chip->dev->of_node);
 200 }
 201
 202 static void of_pwmchip_remove(struct pwm_chip *chip)
 203 {
 204         if (chip->dev)
 205                 of_node_put(chip->dev->of_node);
 206 }
 207
 208 /**
 209  * pwm_set_chip_data() - set private chip data for a PWM
 210  * @pwm: PWM device
 211  * @data: pointer to chip-specific data
 212  *
 213  * Returns: 0 on success or a negative error code on failure.
 214  */
 215 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
 216 {
 217         if (!pwm)
 218                 return -EINVAL;
 219
 220         pwm->chip_data = data;
 221
 222         return 0;
 223 }
 224 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
 225
 226 /**
 227  * pwm_get_chip_data() - get private chip data for a PWM
 228  * @pwm: PWM device
 229  *
 230  * Returns: A pointer to the chip-private data for the PWM device.
 231  */
 232 void *pwm_get_chip_data(struct pwm_device *pwm)
 233 {
 234         return pwm ? pwm->chip_data : NULL;
 235 }
 236 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
 237
 238 static bool pwm_ops_check(const struct pwm_chip *chip)
 239 {
 240
 241         const struct pwm_ops *ops = chip->ops;
 242
 243         /* driver supports legacy, non-atomic operation */
 244         if (ops->config && ops->enable && ops->disable) {
 245                 if (IS_ENABLED(CONFIG_PWM_DEBUG))
 246                         dev_warn(chip->dev,
 247                                  "Driver needs updating to atomic API\n");
 248
 249                 return true;
 250         }
 251
 252         if (!ops->apply)
 253                 return false;
 254
 255         if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
 256                 dev_warn(chip->dev,
 257                          "Please implement the .get_state() callback\n");
 258
 259         return true;
 260 }
 261
 262 /**
 263  * pwmchip_add_with_polarity() - register a new PWM chip
 264  * @chip: the PWM chip to add
 265  * @polarity: initial polarity of PWM channels
 266  *
 267  * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
 268  * will be used. The initial polarity for all channels is specified by the
 269  * @polarity parameter.
 270  *
 271  * Returns: 0 on success or a negative error code on failure.
 272  */
 273 int pwmchip_add_with_polarity(struct pwm_chip *chip,
 274                               enum pwm_polarity polarity)
 275 {
 276         struct pwm_device *pwm;
 277         unsigned int i;
 278         int ret;
 279
 280         if (!chip || !chip->dev || !chip->ops || !chip->npwm)
 281                 return -EINVAL;
 282
 283         if (!pwm_ops_check(chip))
 284                 return -EINVAL;
 285
 286         mutex_lock(&pwm_lock);
 287
 288         ret = alloc_pwms(chip->base, chip->npwm);
 289         if (ret < 0)
 290                 goto out;
 291
 292         chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
 293         if (!chip->pwms) {
 294                 ret = -ENOMEM;
 295                 goto out;
 296         }
 297
 298         chip->base = ret;
 299
 300         for (i = 0; i < chip->npwm; i++) {
 301                 pwm = &chip->pwms[i];
 302
 303                 pwm->chip = chip;
 304                 pwm->pwm = chip->base + i;
 305                 pwm->hwpwm = i;
 306                 pwm->state.polarity = polarity;
 307
 308                 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
 309         }
 310
 311         bitmap_set(allocated_pwms, chip->base, chip->npwm);
 312
 313         INIT_LIST_HEAD(&chip->list);
 314         list_add(&chip->list, &pwm_chips);
 315
 316         ret = 0;
 317
 318         if (IS_ENABLED(CONFIG_OF))
 319                 of_pwmchip_add(chip);
 320
 321 out:
 322         mutex_unlock(&pwm_lock);
 323
 324         if (!ret)
 325                 pwmchip_sysfs_export(chip);
 326
 327         return ret;
 328 }
 329 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
 330
 331 /**
 332  * pwmchip_add() - register a new PWM chip
 333  * @chip: the PWM chip to add
 334  *
 335  * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
 336  * will be used. The initial polarity for all channels is normal.
 337  *
 338  * Returns: 0 on success or a negative error code on failure.
 339  */
 340 int pwmchip_add(struct pwm_chip *chip)
 341 {
 342         return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
 343 }
 344 EXPORT_SYMBOL_GPL(pwmchip_add);
 345
 346 /**
 347  * pwmchip_remove() - remove a PWM chip
 348  * @chip: the PWM chip to remove
 349  *
 350  * Removes a PWM chip. This function may return busy if the PWM chip provides
 351  * a PWM device that is still requested.
 352  *
 353  * Returns: 0 on success or a negative error code on failure.
 354  */
 355 int pwmchip_remove(struct pwm_chip *chip)
 356 {
 357         unsigned int i;
 358         int ret = 0;
 359
 360         pwmchip_sysfs_unexport(chip);
 361
 362         mutex_lock(&pwm_lock);
 363
 364         for (i = 0; i < chip->npwm; i++) {
 365                 struct pwm_device *pwm = &chip->pwms[i];
 366
 367                 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
 368                         ret = -EBUSY;
 369                         goto out;
 370                 }
 371         }
 372
 373         list_del_init(&chip->list);
 374
 375         if (IS_ENABLED(CONFIG_OF))
 376                 of_pwmchip_remove(chip);
 377
 378         free_pwms(chip);
 379
 380 out:
 381         mutex_unlock(&pwm_lock);
 382         return ret;
 383 }
 384 EXPORT_SYMBOL_GPL(pwmchip_remove);
 385
 386 /**
 387  * pwm_request() - request a PWM device
 388  * @pwm: global PWM device index
 389  * @label: PWM device label
 390  *
 391  * This function is deprecated, use pwm_get() instead.
 392  *
 393  * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
 394  * failure.
 395  */
 396 struct pwm_device *pwm_request(int pwm, const char *label)
 397 {
 398         struct pwm_device *dev;
 399         int err;
 400
 401         if (pwm < 0 || pwm >= MAX_PWMS)
 402                 return ERR_PTR(-EINVAL);
 403
 404         mutex_lock(&pwm_lock);
 405
 406         dev = pwm_to_device(pwm);
 407         if (!dev) {
 408                 dev = ERR_PTR(-EPROBE_DEFER);
 409                 goto out;
 410         }
 411
 412         err = pwm_device_request(dev, label);
 413         if (err < 0)
 414                 dev = ERR_PTR(err);
 415
 416 out:
 417         mutex_unlock(&pwm_lock);
 418
 419         return dev;
 420 }
 421 EXPORT_SYMBOL_GPL(pwm_request);
 422
 423 /**
 424  * pwm_request_from_chip() - request a PWM device relative to a PWM chip
 425  * @chip: PWM chip
 426  * @index: per-chip index of the PWM to request
 427  * @label: a literal description string of this PWM
 428  *
 429  * Returns: A pointer to the PWM device at the given index of the given PWM
 430  * chip. A negative error code is returned if the index is not valid for the
 431  * specified PWM chip or if the PWM device cannot be requested.
 432  */
 433 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 434                                          unsigned int index,
 435                                          const char *label)
 436 {
 437         struct pwm_device *pwm;
 438         int err;
 439
 440         if (!chip || index >= chip->npwm)
 441                 return ERR_PTR(-EINVAL);
 442
 443         mutex_lock(&pwm_lock);
 444         pwm = &chip->pwms[index];
 445
 446         err = pwm_device_request(pwm, label);
 447         if (err < 0)
 448                 pwm = ERR_PTR(err);
 449
 450         mutex_unlock(&pwm_lock);
 451         return pwm;
 452 }
 453 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
 454
 455 /**
 456  * pwm_free() - free a PWM device
 457  * @pwm: PWM device
 458  *
 459  * This function is deprecated, use pwm_put() instead.
 460  */
 461 void pwm_free(struct pwm_device *pwm)
 462 {
 463         pwm_put(pwm);
 464 }
 465 EXPORT_SYMBOL_GPL(pwm_free);
 466
 467 static void pwm_apply_state_debug(struct pwm_device *pwm,
 468                                   const struct pwm_state *state)
 469 {
 470         struct pwm_state *last = &pwm->last;
 471         struct pwm_chip *chip = pwm->chip;
 472         struct pwm_state s1, s2;
 473         int err;
 474
 475         if (!IS_ENABLED(CONFIG_PWM_DEBUG))
 476                 return;
 477
 478         /* No reasonable diagnosis possible without .get_state() */
 479         if (!chip->ops->get_state)
 480                 return;
 481
 482         /*
 483          * *state was just applied. Read out the hardware state and do some
 484          * checks.
 485          */
 486
 487         chip->ops->get_state(chip, pwm, &s1);
 488         trace_pwm_get(pwm, &s1);
 489
 490         /*
 491          * The lowlevel driver either ignored .polarity (which is a bug) or as
 492          * best effort inverted .polarity and fixed .duty_cycle respectively.
 493          * Undo this inversion and fixup for further tests.
 494          */
 495         if (s1.enabled && s1.polarity != state->polarity) {
 496                 s2.polarity = state->polarity;
 497                 s2.duty_cycle = s1.period - s1.duty_cycle;
 498                 s2.period = s1.period;
 499                 s2.enabled = s1.enabled;
 500         } else {
 501                 s2 = s1;
 502         }
 503
 504         if (s2.polarity != state->polarity &&
 505             state->duty_cycle < state->period)
 506                 dev_warn(chip->dev, ".apply ignored .polarity\n");
 507
 508         if (state->enabled &&
 509             last->polarity == state->polarity &&
 510             last->period > s2.period &&
 511             last->period <= state->period)
 512                 dev_warn(chip->dev,
 513                          ".apply didn't pick the best available period (requested: %u, applied: %u, possible: %u)\n",
 514                          state->period, s2.period, last->period);
 515
 516         if (state->enabled && state->period < s2.period)
 517                 dev_warn(chip->dev,
 518                          ".apply is supposed to round down period (requested: %u, applied: %u)\n",
 519                          state->period, s2.period);
 520
 521         if (state->enabled &&
 522             last->polarity == state->polarity &&
 523             last->period == s2.period &&
 524             last->duty_cycle > s2.duty_cycle &&
 525             last->duty_cycle <= state->duty_cycle)
 526                 dev_warn(chip->dev,
 527                          ".apply didn't pick the best available duty cycle (requested: %u/%u, applied: %u/%u, possible: %u/%u)\n",
 528                          state->duty_cycle, state->period,
 529                          s2.duty_cycle, s2.period,
 530                          last->duty_cycle, last->period);
 531
 532         if (state->enabled && state->duty_cycle < s2.duty_cycle)
 533                 dev_warn(chip->dev,
 534                          ".apply is supposed to round down duty_cycle (requested: %u/%u, applied: %u/%u)\n",
 535                          state->duty_cycle, state->period,
 536                          s2.duty_cycle, s2.period);
 537
 538         if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
 539                 dev_warn(chip->dev,
 540                          "requested disabled, but yielded enabled with duty > 0");
 541
 542         /* reapply the state that the driver reported being configured. */
 543         err = chip->ops->apply(chip, pwm, &s1);
 544         if (err) {
 545                 *last = s1;
 546                 dev_err(chip->dev, "failed to reapply current setting\n");
 547                 return;
 548         }
 549
 550         trace_pwm_apply(pwm, &s1);
 551
 552         chip->ops->get_state(chip, pwm, last);
 553         trace_pwm_get(pwm, last);
 554
 555         /* reapplication of the current state should give an exact match */
 556         if (s1.enabled != last->enabled ||
 557             s1.polarity != last->polarity ||
 558             (s1.enabled && s1.period != last->period) ||
 559             (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
 560                 dev_err(chip->dev,
 561                         ".apply is not idempotent (ena=%d pol=%d %u/%u) -> (ena=%d pol=%d %u/%u)\n",
 562                         s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
 563                         last->enabled, last->polarity, last->duty_cycle,
 564                         last->period);
 565         }
 566 }
 567
 568 /**
 569  * pwm_apply_state() - atomically apply a new state to a PWM device
 570  * @pwm: PWM device
 571  * @state: new state to apply
 572  */
 573 int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
 574 {
 575         struct pwm_chip *chip;
 576         int err;
 577
 578         if (!pwm || !state || !state->period ||
 579             state->duty_cycle > state->period)
 580                 return -EINVAL;
 581
 582         chip = pwm->chip;
 583
 584         if (state->period == pwm->state.period &&
 585             state->duty_cycle == pwm->state.duty_cycle &&
 586             state->polarity == pwm->state.polarity &&
 587             state->enabled == pwm->state.enabled)
 588                 return 0;
 589
 590         if (chip->ops->apply) {
 591                 err = chip->ops->apply(chip, pwm, state);
 592                 if (err)
 593                         return err;
 594
 595                 trace_pwm_apply(pwm, state);
 596
 597                 pwm->state = *state;
 598
 599                 /*
 600                  * only do this after pwm->state was applied as some
 601                  * implementations of .get_state depend on this
 602                  */
 603                 pwm_apply_state_debug(pwm, state);
 604         } else {
 605                 /*
 606                  * FIXME: restore the initial state in case of error.
 607                  */
 608                 if (state->polarity != pwm->state.polarity) {
 609                         if (!chip->ops->set_polarity)
 610                                 return -ENOTSUPP;
 611
 612                         /*
 613                          * Changing the polarity of a running PWM is
 614                          * only allowed when the PWM driver implements
 615                          * ->apply().
 616                          */
 617                         if (pwm->state.enabled) {
 618                                 chip->ops->disable(chip, pwm);
 619                                 pwm->state.enabled = false;
 620                         }
 621
 622                         err = chip->ops->set_polarity(chip, pwm,
 623                                                       state->polarity);
 624                         if (err)
 625                                 return err;
 626
 627                         pwm->state.polarity = state->polarity;
 628                 }
 629
 630                 if (state->period != pwm->state.period ||
 631                     state->duty_cycle != pwm->state.duty_cycle) {
 632                         err = chip->ops->config(pwm->chip, pwm,
 633                                                 state->duty_cycle,
 634                                                 state->period);
 635                         if (err)
 636                                 return err;
 637
 638                         pwm->state.duty_cycle = state->duty_cycle;
 639                         pwm->state.period = state->period;
 640                 }
 641
 642                 if (state->enabled != pwm->state.enabled) {
 643                         if (state->enabled) {
 644                                 err = chip->ops->enable(chip, pwm);
 645                                 if (err)
 646                                         return err;
 647                         } else {
 648                                 chip->ops->disable(chip, pwm);
 649                         }
 650
 651                         pwm->state.enabled = state->enabled;
 652                 }
 653         }
 654
 655         return 0;
 656 }
 657 EXPORT_SYMBOL_GPL(pwm_apply_state);
 658
 659 /**
 660  * pwm_capture() - capture and report a PWM signal
 661  * @pwm: PWM device
 662  * @result: structure to fill with capture result
 663  * @timeout: time to wait, in milliseconds, before giving up on capture
 664  *
 665  * Returns: 0 on success or a negative error code on failure.
 666  */
 667 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
 668                 unsigned long timeout)
 669 {
 670         int err;
 671
 672         if (!pwm || !pwm->chip->ops)
 673                 return -EINVAL;
 674
 675         if (!pwm->chip->ops->capture)
 676                 return -ENOSYS;
 677
 678         mutex_lock(&pwm_lock);
 679         err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
 680         mutex_unlock(&pwm_lock);
 681
 682         return err;
 683 }
 684 EXPORT_SYMBOL_GPL(pwm_capture);
 685
 686 /**
 687  * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
 688  * @pwm: PWM device
 689  *
 690  * This function will adjust the PWM config to the PWM arguments provided
 691  * by the DT or PWM lookup table. This is particularly useful to adapt
 692  * the bootloader config to the Linux one.
 693  */
 694 int pwm_adjust_config(struct pwm_device *pwm)
 695 {
 696         struct pwm_state state;
 697         struct pwm_args pargs;
 698
 699         pwm_get_args(pwm, &pargs);
 700         pwm_get_state(pwm, &state);
 701
 702         /*
 703          * If the current period is zero it means that either the PWM driver
 704          * does not support initial state retrieval or the PWM has not yet
 705          * been configured.
 706          *
 707          * In either case, we setup the new period and polarity, and assign a
 708          * duty cycle of 0.
 709          */
 710         if (!state.period) {
 711                 state.duty_cycle = 0;
 712                 state.period = pargs.period;
 713                 state.polarity = pargs.polarity;
 714
 715                 return pwm_apply_state(pwm, &state);
 716         }
 717
 718         /*
 719          * Adjust the PWM duty cycle/period based on the period value provided
 720          * in PWM args.
 721          */
 722         if (pargs.period != state.period) {
 723                 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
 724
 725                 do_div(dutycycle, state.period);
 726                 state.duty_cycle = dutycycle;
 727                 state.period = pargs.period;
 728         }
 729
 730         /*
 731          * If the polarity changed, we should also change the duty cycle.
 732          */
 733         if (pargs.polarity != state.polarity) {
 734                 state.polarity = pargs.polarity;
 735                 state.duty_cycle = state.period - state.duty_cycle;
 736         }
 737
 738         return pwm_apply_state(pwm, &state);
 739 }
 740 EXPORT_SYMBOL_GPL(pwm_adjust_config);
 741
 742 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
 743 {
 744         struct pwm_chip *chip;
 745
 746         mutex_lock(&pwm_lock);
 747
 748         list_for_each_entry(chip, &pwm_chips, list)
 749                 if (chip->dev && chip->dev->of_node == np) {
 750                         mutex_unlock(&pwm_lock);
 751                         return chip;
 752                 }
 753
 754         mutex_unlock(&pwm_lock);
 755
 756         return ERR_PTR(-EPROBE_DEFER);
 757 }
 758
 759 static struct device_link *pwm_device_link_add(struct device *dev,
 760                                                struct pwm_device *pwm)
 761 {
 762         struct device_link *dl;
 763
 764         if (!dev) {
 765                 /*
 766                  * No device for the PWM consumer has been provided. It may
 767                  * impact the PM sequence ordering: the PWM supplier may get
 768                  * suspended before the consumer.
 769                  */
 770                 dev_warn(pwm->chip->dev,
 771                          "No consumer device specified to create a link to\n");
 772                 return NULL;
 773         }
 774
 775         dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
 776         if (!dl) {
 777                 dev_err(dev, "failed to create device link to %s\n",
 778                         dev_name(pwm->chip->dev));
 779                 return ERR_PTR(-EINVAL);
 780         }
 781
 782         return dl;
 783 }
 784
 785 /**
 786  * of_pwm_get() - request a PWM via the PWM framework
 787  * @dev: device for PWM consumer
 788  * @np: device node to get the PWM from
 789  * @con_id: consumer name
 790  *
 791  * Returns the PWM device parsed from the phandle and index specified in the
 792  * "pwms" property of a device tree node or a negative error-code on failure.
 793  * Values parsed from the device tree are stored in the returned PWM device
 794  * object.
 795  *
 796  * If con_id is NULL, the first PWM device listed in the "pwms" property will
 797  * be requested. Otherwise the "pwm-names" property is used to do a reverse
 798  * lookup of the PWM index. This also means that the "pwm-names" property
 799  * becomes mandatory for devices that look up the PWM device via the con_id
 800  * parameter.
 801  *
 802  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 803  * error code on failure.
 804  */
 805 struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
 806                               const char *con_id)
 807 {
 808         struct pwm_device *pwm = NULL;
 809         struct of_phandle_args args;
 810         struct device_link *dl;
 811         struct pwm_chip *pc;
 812         int index = 0;
 813         int err;
 814
 815         if (con_id) {
 816                 index = of_property_match_string(np, "pwm-names", con_id);
 817                 if (index < 0)
 818                         return ERR_PTR(index);
 819         }
 820
 821         err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
 822                                          &args);
 823         if (err) {
 824                 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
 825                 return ERR_PTR(err);
 826         }
 827
 828         pc = of_node_to_pwmchip(args.np);
 829         if (IS_ERR(pc)) {
 830                 if (PTR_ERR(pc) != -EPROBE_DEFER)
 831                         pr_err("%s(): PWM chip not found\n", __func__);
 832
 833                 pwm = ERR_CAST(pc);
 834                 goto put;
 835         }
 836
 837         pwm = pc->of_xlate(pc, &args);
 838         if (IS_ERR(pwm))
 839                 goto put;
 840
 841         dl = pwm_device_link_add(dev, pwm);
 842         if (IS_ERR(dl)) {
 843                 /* of_xlate ended up calling pwm_request_from_chip() */
 844                 pwm_free(pwm);
 845                 pwm = ERR_CAST(dl);
 846                 goto put;
 847         }
 848
 849         /*
 850          * If a consumer name was not given, try to look it up from the
 851          * "pwm-names" property if it exists. Otherwise use the name of
 852          * the user device node.
 853          */
 854         if (!con_id) {
 855                 err = of_property_read_string_index(np, "pwm-names", index,
 856                                                     &con_id);
 857                 if (err < 0)
 858                         con_id = np->name;
 859         }
 860
 861         pwm->label = con_id;
 862
 863 put:
 864         of_node_put(args.np);
 865
 866         return pwm;
 867 }
 868 EXPORT_SYMBOL_GPL(of_pwm_get);
 869
 870 #if IS_ENABLED(CONFIG_ACPI)
 871 static struct pwm_chip *device_to_pwmchip(struct device *dev)
 872 {
 873         struct pwm_chip *chip;
 874
 875         mutex_lock(&pwm_lock);
 876
 877         list_for_each_entry(chip, &pwm_chips, list) {
 878                 struct acpi_device *adev = ACPI_COMPANION(chip->dev);
 879
 880                 if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
 881                         mutex_unlock(&pwm_lock);
 882                         return chip;
 883                 }
 884         }
 885
 886         mutex_unlock(&pwm_lock);
 887
 888         return ERR_PTR(-EPROBE_DEFER);
 889 }
 890 #endif
 891
 892 /**
 893  * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
 894  * @fwnode: firmware node to get the "pwm" property from
 895  *
 896  * Returns the PWM device parsed from the fwnode and index specified in the
 897  * "pwms" property or a negative error-code on failure.
 898  * Values parsed from the device tree are stored in the returned PWM device
 899  * object.
 900  *
 901  * This is analogous to of_pwm_get() except con_id is not yet supported.
 902  * ACPI entries must look like
 903  * Package () {"pwms", Package ()
 904  *     { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
 905  *
 906  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 907  * error code on failure.
 908  */
 909 static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
 910 {
 911         struct pwm_device *pwm = ERR_PTR(-ENODEV);
 912 #if IS_ENABLED(CONFIG_ACPI)
 913         struct fwnode_reference_args args;
 914         struct acpi_device *acpi;
 915         struct pwm_chip *chip;
 916         int ret;
 917
 918         memset(&args, 0, sizeof(args));
 919
 920         ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
 921         if (ret < 0)
 922                 return ERR_PTR(ret);
 923
 924         acpi = to_acpi_device_node(args.fwnode);
 925         if (!acpi)
 926                 return ERR_PTR(-EINVAL);
 927
 928         if (args.nargs < 2)
 929                 return ERR_PTR(-EPROTO);
 930
 931         chip = device_to_pwmchip(&acpi->dev);
 932         if (IS_ERR(chip))
 933                 return ERR_CAST(chip);
 934
 935         pwm = pwm_request_from_chip(chip, args.args[0], NULL);
 936         if (IS_ERR(pwm))
 937                 return pwm;
 938
 939         pwm->args.period = args.args[1];
 940         pwm->args.polarity = PWM_POLARITY_NORMAL;
 941
 942         if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
 943                 pwm->args.polarity = PWM_POLARITY_INVERSED;
 944 #endif
 945
 946         return pwm;
 947 }
 948
 949 /**
 950  * pwm_add_table() - register PWM device consumers
 951  * @table: array of consumers to register
 952  * @num: number of consumers in table
 953  */
 954 void pwm_add_table(struct pwm_lookup *table, size_t num)
 955 {
 956         mutex_lock(&pwm_lookup_lock);
 957
 958         while (num--) {
 959                 list_add_tail(&table->list, &pwm_lookup_list);
 960                 table++;
 961         }
 962
 963         mutex_unlock(&pwm_lookup_lock);
 964 }
 965
 966 /**
 967  * pwm_remove_table() - unregister PWM device consumers
 968  * @table: array of consumers to unregister
 969  * @num: number of consumers in table
 970  */
 971 void pwm_remove_table(struct pwm_lookup *table, size_t num)
 972 {
 973         mutex_lock(&pwm_lookup_lock);
 974
 975         while (num--) {
 976                 list_del(&table->list);
 977                 table++;
 978         }
 979
 980         mutex_unlock(&pwm_lookup_lock);
 981 }
 982
 983 /**
 984  * pwm_get() - look up and request a PWM device
 985  * @dev: device for PWM consumer
 986  * @con_id: consumer name
 987  *
 988  * Lookup is first attempted using DT. If the device was not instantiated from
 989  * a device tree, a PWM chip and a relative index is looked up via a table
 990  * supplied by board setup code (see pwm_add_table()).
 991  *
 992  * Once a PWM chip has been found the specified PWM device will be requested
 993  * and is ready to be used.
 994  *
 995  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 996  * error code on failure.
 997  */
 998 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 999 {
1000         const char *dev_id = dev ? dev_name(dev) : NULL;
1001         struct pwm_device *pwm;
1002         struct pwm_chip *chip;
1003         struct device_link *dl;
1004         unsigned int best = 0;
1005         struct pwm_lookup *p, *chosen = NULL;
1006         unsigned int match;
1007         int err;
1008
1009         /* look up via DT first */
1010         if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
1011                 return of_pwm_get(dev, dev->of_node, con_id);
1012
1013         /* then lookup via ACPI */
1014         if (dev && is_acpi_node(dev->fwnode)) {
1015                 pwm = acpi_pwm_get(dev->fwnode);
1016                 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
1017                         return pwm;
1018         }
1019
1020         /*
1021          * We look up the provider in the static table typically provided by
1022          * board setup code. We first try to lookup the consumer device by
1023          * name. If the consumer device was passed in as NULL or if no match
1024          * was found, we try to find the consumer by directly looking it up
1025          * by name.
1026          *
1027          * If a match is found, the provider PWM chip is looked up by name
1028          * and a PWM device is requested using the PWM device per-chip index.
1029          *
1030          * The lookup algorithm was shamelessly taken from the clock
1031          * framework:
1032          *
1033          * We do slightly fuzzy matching here:
1034          *  An entry with a NULL ID is assumed to be a wildcard.
1035          *  If an entry has a device ID, it must match
1036          *  If an entry has a connection ID, it must match
1037          * Then we take the most specific entry - with the following order
1038          * of precedence: dev+con > dev only > con only.
1039          */
1040         mutex_lock(&pwm_lookup_lock);
1041
1042         list_for_each_entry(p, &pwm_lookup_list, list) {
1043                 match = 0;
1044
1045                 if (p->dev_id) {
1046                         if (!dev_id || strcmp(p->dev_id, dev_id))
1047                                 continue;
1048
1049                         match += 2;
1050                 }
1051
1052                 if (p->con_id) {
1053                         if (!con_id || strcmp(p->con_id, con_id))
1054                                 continue;
1055
1056                         match += 1;
1057                 }
1058
1059                 if (match > best) {
1060                         chosen = p;
1061
1062                         if (match != 3)
1063                                 best = match;
1064                         else
1065                                 break;
1066                 }
1067         }
1068
1069         mutex_unlock(&pwm_lookup_lock);
1070
1071         if (!chosen)
1072                 return ERR_PTR(-ENODEV);
1073
1074         chip = pwmchip_find_by_name(chosen->provider);
1075
1076         /*
1077          * If the lookup entry specifies a module, load the module and retry
1078          * the PWM chip lookup. This can be used to work around driver load
1079          * ordering issues if driver's can't be made to properly support the
1080          * deferred probe mechanism.
1081          */
1082         if (!chip && chosen->module) {
1083                 err = request_module(chosen->module);
1084                 if (err == 0)
1085                         chip = pwmchip_find_by_name(chosen->provider);
1086         }
1087
1088         if (!chip)
1089                 return ERR_PTR(-EPROBE_DEFER);
1090
1091         pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1092         if (IS_ERR(pwm))
1093                 return pwm;
1094
1095         dl = pwm_device_link_add(dev, pwm);
1096         if (IS_ERR(dl)) {
1097                 pwm_free(pwm);
1098                 return ERR_CAST(dl);
1099         }
1100
1101         pwm->args.period = chosen->period;
1102         pwm->args.polarity = chosen->polarity;
1103
1104         return pwm;
1105 }
1106 EXPORT_SYMBOL_GPL(pwm_get);
1107
1108 /**
1109  * pwm_put() - release a PWM device
1110  * @pwm: PWM device
1111  */
1112 void pwm_put(struct pwm_device *pwm)
1113 {
1114         if (!pwm)
1115                 return;
1116
1117         mutex_lock(&pwm_lock);
1118
1119         if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1120                 pr_warn("PWM device already freed\n");
1121                 goto out;
1122         }
1123
1124         if (pwm->chip->ops->free)
1125                 pwm->chip->ops->free(pwm->chip, pwm);
1126
1127         pwm_set_chip_data(pwm, NULL);
1128         pwm->label = NULL;
1129
1130         module_put(pwm->chip->ops->owner);
1131 out:
1132         mutex_unlock(&pwm_lock);
1133 }
1134 EXPORT_SYMBOL_GPL(pwm_put);
1135
1136 static void devm_pwm_release(struct device *dev, void *res)
1137 {
1138         pwm_put(*(struct pwm_device **)res);
1139 }
1140
1141 /**
1142  * devm_pwm_get() - resource managed pwm_get()
1143  * @dev: device for PWM consumer
1144  * @con_id: consumer name
1145  *
1146  * This function performs like pwm_get() but the acquired PWM device will
1147  * automatically be released on driver detach.
1148  *
1149  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1150  * error code on failure.
1151  */
1152 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1153 {
1154         struct pwm_device **ptr, *pwm;
1155
1156         ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1157         if (!ptr)
1158                 return ERR_PTR(-ENOMEM);
1159
1160         pwm = pwm_get(dev, con_id);
1161         if (!IS_ERR(pwm)) {
1162                 *ptr = pwm;
1163                 devres_add(dev, ptr);
1164         } else {
1165                 devres_free(ptr);
1166         }
1167
1168         return pwm;
1169 }
1170 EXPORT_SYMBOL_GPL(devm_pwm_get);
1171
1172 /**
1173  * devm_of_pwm_get() - resource managed of_pwm_get()
1174  * @dev: device for PWM consumer
1175  * @np: device node to get the PWM from
1176  * @con_id: consumer name
1177  *
1178  * This function performs like of_pwm_get() but the acquired PWM device will
1179  * automatically be released on driver detach.
1180  *
1181  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1182  * error code on failure.
1183  */
1184 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
1185                                    const char *con_id)
1186 {
1187         struct pwm_device **ptr, *pwm;
1188
1189         ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1190         if (!ptr)
1191                 return ERR_PTR(-ENOMEM);
1192
1193         pwm = of_pwm_get(dev, np, con_id);
1194         if (!IS_ERR(pwm)) {
1195                 *ptr = pwm;
1196                 devres_add(dev, ptr);
1197         } else {
1198                 devres_free(ptr);
1199         }
1200
1201         return pwm;
1202 }
1203 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
1204
1205 /**
1206  * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1207  * @dev: device for PWM consumer
1208  * @fwnode: firmware node to get the PWM from
1209  * @con_id: consumer name
1210  *
1211  * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1212  * acpi_pwm_get() for a detailed description.
1213  *
1214  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1215  * error code on failure.
1216  */
1217 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1218                                        struct fwnode_handle *fwnode,
1219                                        const char *con_id)
1220 {
1221         struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV);
1222
1223         ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1224         if (!ptr)
1225                 return ERR_PTR(-ENOMEM);
1226
1227         if (is_of_node(fwnode))
1228                 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1229         else if (is_acpi_node(fwnode))
1230                 pwm = acpi_pwm_get(fwnode);
1231
1232         if (!IS_ERR(pwm)) {
1233                 *ptr = pwm;
1234                 devres_add(dev, ptr);
1235         } else {
1236                 devres_free(ptr);
1237         }
1238
1239         return pwm;
1240 }
1241 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1242
1243 static int devm_pwm_match(struct device *dev, void *res, void *data)
1244 {
1245         struct pwm_device **p = res;
1246
1247         if (WARN_ON(!p || !*p))
1248                 return 0;
1249
1250         return *p == data;
1251 }
1252
1253 /**
1254  * devm_pwm_put() - resource managed pwm_put()
1255  * @dev: device for PWM consumer
1256  * @pwm: PWM device
1257  *
1258  * Release a PWM previously allocated using devm_pwm_get(). Calling this
1259  * function is usually not needed because devm-allocated resources are
1260  * automatically released on driver detach.
1261  */
1262 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
1263 {
1264         WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
1265 }
1266 EXPORT_SYMBOL_GPL(devm_pwm_put);
1267
1268 #ifdef CONFIG_DEBUG_FS
1269 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1270 {
1271         unsigned int i;
1272
1273         for (i = 0; i < chip->npwm; i++) {
1274                 struct pwm_device *pwm = &chip->pwms[i];
1275                 struct pwm_state state;
1276
1277                 pwm_get_state(pwm, &state);
1278
1279                 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1280
1281                 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1282                         seq_puts(s, " requested");
1283
1284                 if (state.enabled)
1285                         seq_puts(s, " enabled");
1286
1287                 seq_printf(s, " period: %u ns", state.period);
1288                 seq_printf(s, " duty: %u ns", state.duty_cycle);
1289                 seq_printf(s, " polarity: %s",
1290                            state.polarity ? "inverse" : "normal");
1291
1292                 seq_puts(s, "\n");
1293         }
1294 }
1295
1296 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1297 {
1298         mutex_lock(&pwm_lock);
1299         s->private = "";
1300
1301         return seq_list_start(&pwm_chips, *pos);
1302 }
1303
1304 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1305 {
1306         s->private = "\n";
1307
1308         return seq_list_next(v, &pwm_chips, pos);
1309 }
1310
1311 static void pwm_seq_stop(struct seq_file *s, void *v)
1312 {
1313         mutex_unlock(&pwm_lock);
1314 }
1315
1316 static int pwm_seq_show(struct seq_file *s, void *v)
1317 {
1318         struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1319
1320         seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1321                    chip->dev->bus ? chip->dev->bus->name : "no-bus",
1322                    dev_name(chip->dev), chip->npwm,
1323                    (chip->npwm != 1) ? "s" : "");
1324
1325         pwm_dbg_show(chip, s);
1326
1327         return 0;
1328 }
1329
1330 static const struct seq_operations pwm_seq_ops = {
1331         .start = pwm_seq_start,
1332         .next = pwm_seq_next,
1333         .stop = pwm_seq_stop,
1334         .show = pwm_seq_show,
1335 };
1336
1337 static int pwm_seq_open(struct inode *inode, struct file *file)
1338 {
1339         return seq_open(file, &pwm_seq_ops);
1340 }
1341
1342 static const struct file_operations pwm_debugfs_ops = {
1343         .owner = THIS_MODULE,
1344         .open = pwm_seq_open,
1345         .read = seq_read,
1346         .llseek = seq_lseek,
1347         .release = seq_release,
1348 };
1349
1350 static int __init pwm_debugfs_init(void)
1351 {
1352         debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1353                             &pwm_debugfs_ops);
1354
1355         return 0;
1356 }
1357 subsys_initcall(pwm_debugfs_init);
1358 #endif /* CONFIG_DEBUG_FS */