drivers/pwm/core.c

   1 /*
   2  * Generic pwmlib implementation
   3  *
   4  * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
   5  * Copyright (C) 2011-2012 Avionic Design GmbH
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2, or (at your option)
  10  *  any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; see the file COPYING.  If not, write to
  19  *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/pwm.h>
  24 #include <linux/radix-tree.h>
  25 #include <linux/list.h>
  26 #include <linux/mutex.h>
  27 #include <linux/err.h>
  28 #include <linux/slab.h>
  29 #include <linux/device.h>
  30 #include <linux/debugfs.h>
  31 #include <linux/seq_file.h>
  32
  33 #include <dt-bindings/pwm/pwm.h>
  34
  35 #define MAX_PWMS 1024
  36
  37 static DEFINE_MUTEX(pwm_lookup_lock);
  38 static LIST_HEAD(pwm_lookup_list);
  39 static DEFINE_MUTEX(pwm_lock);
  40 static LIST_HEAD(pwm_chips);
  41 static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
  42 static RADIX_TREE(pwm_tree, GFP_KERNEL);
  43
  44 static struct pwm_device *pwm_to_device(unsigned int pwm)
  45 {
  46         return radix_tree_lookup(&pwm_tree, pwm);
  47 }
  48
  49 static int alloc_pwms(int pwm, unsigned int count)
  50 {
  51         unsigned int from = 0;
  52         unsigned int start;
  53
  54         if (pwm >= MAX_PWMS)
  55                 return -EINVAL;
  56
  57         if (pwm >= 0)
  58                 from = pwm;
  59
  60         start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
  61                                            count, 0);
  62
  63         if (pwm >= 0 && start != pwm)
  64                 return -EEXIST;
  65
  66         if (start + count > MAX_PWMS)
  67                 return -ENOSPC;
  68
  69         return start;
  70 }
  71
  72 static void free_pwms(struct pwm_chip *chip)
  73 {
  74         unsigned int i;
  75
  76         for (i = 0; i < chip->npwm; i++) {
  77                 struct pwm_device *pwm = &chip->pwms[i];
  78                 radix_tree_delete(&pwm_tree, pwm->pwm);
  79         }
  80
  81         bitmap_clear(allocated_pwms, chip->base, chip->npwm);
  82
  83         kfree(chip->pwms);
  84         chip->pwms = NULL;
  85 }
  86
  87 static struct pwm_chip *pwmchip_find_by_name(const char *name)
  88 {
  89         struct pwm_chip *chip;
  90
  91         if (!name)
  92                 return NULL;
  93
  94         mutex_lock(&pwm_lock);
  95
  96         list_for_each_entry(chip, &pwm_chips, list) {
  97                 const char *chip_name = dev_name(chip->dev);
  98
  99                 if (chip_name && strcmp(chip_name, name) == 0) {
 100                         mutex_unlock(&pwm_lock);
 101                         return chip;
 102                 }
 103         }
 104
 105         mutex_unlock(&pwm_lock);
 106
 107         return NULL;
 108 }
 109
 110 static int pwm_device_request(struct pwm_device *pwm, const char *label)
 111 {
 112         int err;
 113
 114         if (test_bit(PWMF_REQUESTED, &pwm->flags))
 115                 return -EBUSY;
 116
 117         if (!try_module_get(pwm->chip->ops->owner))
 118                 return -ENODEV;
 119
 120         if (pwm->chip->ops->request) {
 121                 err = pwm->chip->ops->request(pwm->chip, pwm);
 122                 if (err) {
 123                         module_put(pwm->chip->ops->owner);
 124                         return err;
 125                 }
 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         if (pc->of_pwm_n_cells < 3)
 140                 return ERR_PTR(-EINVAL);
 141
 142         if (args->args[0] >= pc->npwm)
 143                 return ERR_PTR(-EINVAL);
 144
 145         pwm = pwm_request_from_chip(pc, args->args[0], NULL);
 146         if (IS_ERR(pwm))
 147                 return pwm;
 148
 149         pwm_set_period(pwm, args->args[1]);
 150
 151         if (args->args[2] & PWM_POLARITY_INVERTED)
 152                 pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
 153         else
 154                 pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
 155
 156         return pwm;
 157 }
 158 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
 159
 160 static struct pwm_device *
 161 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
 162 {
 163         struct pwm_device *pwm;
 164
 165         if (pc->of_pwm_n_cells < 2)
 166                 return ERR_PTR(-EINVAL);
 167
 168         if (args->args[0] >= pc->npwm)
 169                 return ERR_PTR(-EINVAL);
 170
 171         pwm = pwm_request_from_chip(pc, args->args[0], NULL);
 172         if (IS_ERR(pwm))
 173                 return pwm;
 174
 175         pwm_set_period(pwm, args->args[1]);
 176
 177         return pwm;
 178 }
 179
 180 static void of_pwmchip_add(struct pwm_chip *chip)
 181 {
 182         if (!chip->dev || !chip->dev->of_node)
 183                 return;
 184
 185         if (!chip->of_xlate) {
 186                 chip->of_xlate = of_pwm_simple_xlate;
 187                 chip->of_pwm_n_cells = 2;
 188         }
 189
 190         of_node_get(chip->dev->of_node);
 191 }
 192
 193 static void of_pwmchip_remove(struct pwm_chip *chip)
 194 {
 195         if (chip->dev && chip->dev->of_node)
 196                 of_node_put(chip->dev->of_node);
 197 }
 198
 199 /**
 200  * pwm_set_chip_data() - set private chip data for a PWM
 201  * @pwm: PWM device
 202  * @data: pointer to chip-specific data
 203  */
 204 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
 205 {
 206         if (!pwm)
 207                 return -EINVAL;
 208
 209         pwm->chip_data = data;
 210
 211         return 0;
 212 }
 213 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
 214
 215 /**
 216  * pwm_get_chip_data() - get private chip data for a PWM
 217  * @pwm: PWM device
 218  */
 219 void *pwm_get_chip_data(struct pwm_device *pwm)
 220 {
 221         return pwm ? pwm->chip_data : NULL;
 222 }
 223 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
 224
 225 /**
 226  * pwmchip_add() - register a new PWM chip
 227  * @chip: the PWM chip to add
 228  *
 229  * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
 230  * will be used.
 231  */
 232 int pwmchip_add(struct pwm_chip *chip)
 233 {
 234         struct pwm_device *pwm;
 235         unsigned int i;
 236         int ret;
 237
 238         if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
 239             !chip->ops->enable || !chip->ops->disable)
 240                 return -EINVAL;
 241
 242         mutex_lock(&pwm_lock);
 243
 244         ret = alloc_pwms(chip->base, chip->npwm);
 245         if (ret < 0)
 246                 goto out;
 247
 248         chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
 249         if (!chip->pwms) {
 250                 ret = -ENOMEM;
 251                 goto out;
 252         }
 253
 254         chip->base = ret;
 255
 256         for (i = 0; i < chip->npwm; i++) {
 257                 pwm = &chip->pwms[i];
 258
 259                 pwm->chip = chip;
 260                 pwm->pwm = chip->base + i;
 261                 pwm->hwpwm = i;
 262
 263                 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
 264         }
 265
 266         bitmap_set(allocated_pwms, chip->base, chip->npwm);
 267
 268         INIT_LIST_HEAD(&chip->list);
 269         list_add(&chip->list, &pwm_chips);
 270
 271         ret = 0;
 272
 273         if (IS_ENABLED(CONFIG_OF))
 274                 of_pwmchip_add(chip);
 275
 276         pwmchip_sysfs_export(chip);
 277
 278 out:
 279         mutex_unlock(&pwm_lock);
 280         return ret;
 281 }
 282 EXPORT_SYMBOL_GPL(pwmchip_add);
 283
 284 /**
 285  * pwmchip_remove() - remove a PWM chip
 286  * @chip: the PWM chip to remove
 287  *
 288  * Removes a PWM chip. This function may return busy if the PWM chip provides
 289  * a PWM device that is still requested.
 290  */
 291 int pwmchip_remove(struct pwm_chip *chip)
 292 {
 293         unsigned int i;
 294         int ret = 0;
 295
 296         mutex_lock(&pwm_lock);
 297
 298         for (i = 0; i < chip->npwm; i++) {
 299                 struct pwm_device *pwm = &chip->pwms[i];
 300
 301                 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
 302                         ret = -EBUSY;
 303                         goto out;
 304                 }
 305         }
 306
 307         list_del_init(&chip->list);
 308
 309         if (IS_ENABLED(CONFIG_OF))
 310                 of_pwmchip_remove(chip);
 311
 312         free_pwms(chip);
 313
 314         pwmchip_sysfs_unexport(chip);
 315
 316 out:
 317         mutex_unlock(&pwm_lock);
 318         return ret;
 319 }
 320 EXPORT_SYMBOL_GPL(pwmchip_remove);
 321
 322 /**
 323  * pwm_request() - request a PWM device
 324  * @pwm_id: global PWM device index
 325  * @label: PWM device label
 326  *
 327  * This function is deprecated, use pwm_get() instead.
 328  */
 329 struct pwm_device *pwm_request(int pwm, const char *label)
 330 {
 331         struct pwm_device *dev;
 332         int err;
 333
 334         if (pwm < 0 || pwm >= MAX_PWMS)
 335                 return ERR_PTR(-EINVAL);
 336
 337         mutex_lock(&pwm_lock);
 338
 339         dev = pwm_to_device(pwm);
 340         if (!dev) {
 341                 dev = ERR_PTR(-EPROBE_DEFER);
 342                 goto out;
 343         }
 344
 345         err = pwm_device_request(dev, label);
 346         if (err < 0)
 347                 dev = ERR_PTR(err);
 348
 349 out:
 350         mutex_unlock(&pwm_lock);
 351
 352         return dev;
 353 }
 354 EXPORT_SYMBOL_GPL(pwm_request);
 355
 356 /**
 357  * pwm_request_from_chip() - request a PWM device relative to a PWM chip
 358  * @chip: PWM chip
 359  * @index: per-chip index of the PWM to request
 360  * @label: a literal description string of this PWM
 361  *
 362  * Returns the PWM at the given index of the given PWM chip. A negative error
 363  * code is returned if the index is not valid for the specified PWM chip or
 364  * if the PWM device cannot be requested.
 365  */
 366 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 367                                          unsigned int index,
 368                                          const char *label)
 369 {
 370         struct pwm_device *pwm;
 371         int err;
 372
 373         if (!chip || index >= chip->npwm)
 374                 return ERR_PTR(-EINVAL);
 375
 376         mutex_lock(&pwm_lock);
 377         pwm = &chip->pwms[index];
 378
 379         err = pwm_device_request(pwm, label);
 380         if (err < 0)
 381                 pwm = ERR_PTR(err);
 382
 383         mutex_unlock(&pwm_lock);
 384         return pwm;
 385 }
 386 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
 387
 388 /**
 389  * pwm_free() - free a PWM device
 390  * @pwm: PWM device
 391  *
 392  * This function is deprecated, use pwm_put() instead.
 393  */
 394 void pwm_free(struct pwm_device *pwm)
 395 {
 396         pwm_put(pwm);
 397 }
 398 EXPORT_SYMBOL_GPL(pwm_free);
 399
 400 /**
 401  * pwm_config() - change a PWM device configuration
 402  * @pwm: PWM device
 403  * @duty_ns: "on" time (in nanoseconds)
 404  * @period_ns: duration (in nanoseconds) of one cycle
 405  */
 406 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
 407 {
 408         int err;
 409
 410         if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
 411                 return -EINVAL;
 412
 413         err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
 414         if (err)
 415                 return err;
 416
 417         pwm->duty_cycle = duty_ns;
 418         pwm->period = period_ns;
 419
 420         return 0;
 421 }
 422 EXPORT_SYMBOL_GPL(pwm_config);
 423
 424 /**
 425  * pwm_set_polarity() - configure the polarity of a PWM signal
 426  * @pwm: PWM device
 427  * @polarity: new polarity of the PWM signal
 428  *
 429  * Note that the polarity cannot be configured while the PWM device is enabled
 430  */
 431 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
 432 {
 433         int err;
 434
 435         if (!pwm || !pwm->chip->ops)
 436                 return -EINVAL;
 437
 438         if (!pwm->chip->ops->set_polarity)
 439                 return -ENOSYS;
 440
 441         if (test_bit(PWMF_ENABLED, &pwm->flags))
 442                 return -EBUSY;
 443
 444         err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
 445         if (err)
 446                 return err;
 447
 448         pwm->polarity = polarity;
 449
 450         return 0;
 451 }
 452 EXPORT_SYMBOL_GPL(pwm_set_polarity);
 453
 454 /**
 455  * pwm_enable() - start a PWM output toggling
 456  * @pwm: PWM device
 457  */
 458 int pwm_enable(struct pwm_device *pwm)
 459 {
 460         if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
 461                 return pwm->chip->ops->enable(pwm->chip, pwm);
 462
 463         return pwm ? 0 : -EINVAL;
 464 }
 465 EXPORT_SYMBOL_GPL(pwm_enable);
 466
 467 /**
 468  * pwm_disable() - stop a PWM output toggling
 469  * @pwm: PWM device
 470  */
 471 void pwm_disable(struct pwm_device *pwm)
 472 {
 473         if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
 474                 pwm->chip->ops->disable(pwm->chip, pwm);
 475 }
 476 EXPORT_SYMBOL_GPL(pwm_disable);
 477
 478 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
 479 {
 480         struct pwm_chip *chip;
 481
 482         mutex_lock(&pwm_lock);
 483
 484         list_for_each_entry(chip, &pwm_chips, list)
 485                 if (chip->dev && chip->dev->of_node == np) {
 486                         mutex_unlock(&pwm_lock);
 487                         return chip;
 488                 }
 489
 490         mutex_unlock(&pwm_lock);
 491
 492         return ERR_PTR(-EPROBE_DEFER);
 493 }
 494
 495 /**
 496  * of_pwm_get() - request a PWM via the PWM framework
 497  * @np: device node to get the PWM from
 498  * @con_id: consumer name
 499  *
 500  * Returns the PWM device parsed from the phandle and index specified in the
 501  * "pwms" property of a device tree node or a negative error-code on failure.
 502  * Values parsed from the device tree are stored in the returned PWM device
 503  * object.
 504  *
 505  * If con_id is NULL, the first PWM device listed in the "pwms" property will
 506  * be requested. Otherwise the "pwm-names" property is used to do a reverse
 507  * lookup of the PWM index. This also means that the "pwm-names" property
 508  * becomes mandatory for devices that look up the PWM device via the con_id
 509  * parameter.
 510  */
 511 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 512 {
 513         struct pwm_device *pwm = NULL;
 514         struct of_phandle_args args;
 515         struct pwm_chip *pc;
 516         int index = 0;
 517         int err;
 518
 519         if (con_id) {
 520                 index = of_property_match_string(np, "pwm-names", con_id);
 521                 if (index < 0)
 522                         return ERR_PTR(index);
 523         }
 524
 525         err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
 526                                          &args);
 527         if (err) {
 528                 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
 529                 return ERR_PTR(err);
 530         }
 531
 532         pc = of_node_to_pwmchip(args.np);
 533         if (IS_ERR(pc)) {
 534                 pr_debug("%s(): PWM chip not found\n", __func__);
 535                 pwm = ERR_CAST(pc);
 536                 goto put;
 537         }
 538
 539         if (args.args_count != pc->of_pwm_n_cells) {
 540                 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
 541                          args.np->full_name);
 542                 pwm = ERR_PTR(-EINVAL);
 543                 goto put;
 544         }
 545
 546         pwm = pc->of_xlate(pc, &args);
 547         if (IS_ERR(pwm))
 548                 goto put;
 549
 550         /*
 551          * If a consumer name was not given, try to look it up from the
 552          * "pwm-names" property if it exists. Otherwise use the name of
 553          * the user device node.
 554          */
 555         if (!con_id) {
 556                 err = of_property_read_string_index(np, "pwm-names", index,
 557                                                     &con_id);
 558                 if (err < 0)
 559                         con_id = np->name;
 560         }
 561
 562         pwm->label = con_id;
 563
 564 put:
 565         of_node_put(args.np);
 566
 567         return pwm;
 568 }
 569 EXPORT_SYMBOL_GPL(of_pwm_get);
 570
 571 /**
 572  * pwm_add_table() - register PWM device consumers
 573  * @table: array of consumers to register
 574  * @num: number of consumers in table
 575  */
 576 void __init pwm_add_table(struct pwm_lookup *table, size_t num)
 577 {
 578         mutex_lock(&pwm_lookup_lock);
 579
 580         while (num--) {
 581                 list_add_tail(&table->list, &pwm_lookup_list);
 582                 table++;
 583         }
 584
 585         mutex_unlock(&pwm_lookup_lock);
 586 }
 587
 588 /**
 589  * pwm_get() - look up and request a PWM device
 590  * @dev: device for PWM consumer
 591  * @con_id: consumer name
 592  *
 593  * Lookup is first attempted using DT. If the device was not instantiated from
 594  * a device tree, a PWM chip and a relative index is looked up via a table
 595  * supplied by board setup code (see pwm_add_table()).
 596  *
 597  * Once a PWM chip has been found the specified PWM device will be requested
 598  * and is ready to be used.
 599  */
 600 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 601 {
 602         struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
 603         const char *dev_id = dev ? dev_name(dev) : NULL;
 604         struct pwm_chip *chip = NULL;
 605         unsigned int index = 0;
 606         unsigned int best = 0;
 607         struct pwm_lookup *p;
 608         unsigned int match;
 609         unsigned int period;
 610         enum pwm_polarity polarity;
 611
 612         /* look up via DT first */
 613         if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
 614                 return of_pwm_get(dev->of_node, con_id);
 615
 616         /*
 617          * We look up the provider in the static table typically provided by
 618          * board setup code. We first try to lookup the consumer device by
 619          * name. If the consumer device was passed in as NULL or if no match
 620          * was found, we try to find the consumer by directly looking it up
 621          * by name.
 622          *
 623          * If a match is found, the provider PWM chip is looked up by name
 624          * and a PWM device is requested using the PWM device per-chip index.
 625          *
 626          * The lookup algorithm was shamelessly taken from the clock
 627          * framework:
 628          *
 629          * We do slightly fuzzy matching here:
 630          *  An entry with a NULL ID is assumed to be a wildcard.
 631          *  If an entry has a device ID, it must match
 632          *  If an entry has a connection ID, it must match
 633          * Then we take the most specific entry - with the following order
 634          * of precedence: dev+con > dev only > con only.
 635          */
 636         mutex_lock(&pwm_lookup_lock);
 637
 638         list_for_each_entry(p, &pwm_lookup_list, list) {
 639                 match = 0;
 640
 641                 if (p->dev_id) {
 642                         if (!dev_id || strcmp(p->dev_id, dev_id))
 643                                 continue;
 644
 645                         match += 2;
 646                 }
 647
 648                 if (p->con_id) {
 649                         if (!con_id || strcmp(p->con_id, con_id))
 650                                 continue;
 651
 652                         match += 1;
 653                 }
 654
 655                 if (match > best) {
 656                         chip = pwmchip_find_by_name(p->provider);
 657                         index = p->index;
 658                         period = p->period;
 659                         polarity = p->polarity;
 660
 661                         if (match != 3)
 662                                 best = match;
 663                         else
 664                                 break;
 665                 }
 666         }
 667
 668         mutex_unlock(&pwm_lookup_lock);
 669
 670         if (chip)
 671                 pwm = pwm_request_from_chip(chip, index, con_id ?: dev_id);
 672         if (IS_ERR(pwm))
 673                 return pwm;
 674
 675         pwm_set_period(pwm, period);
 676         pwm_set_polarity(pwm, polarity);
 677
 678
 679         return pwm;
 680 }
 681 EXPORT_SYMBOL_GPL(pwm_get);
 682
 683 /**
 684  * pwm_put() - release a PWM device
 685  * @pwm: PWM device
 686  */
 687 void pwm_put(struct pwm_device *pwm)
 688 {
 689         if (!pwm)
 690                 return;
 691
 692         mutex_lock(&pwm_lock);
 693
 694         if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
 695                 pr_warn("PWM device already freed\n");
 696                 goto out;
 697         }
 698
 699         if (pwm->chip->ops->free)
 700                 pwm->chip->ops->free(pwm->chip, pwm);
 701
 702         pwm->label = NULL;
 703
 704         module_put(pwm->chip->ops->owner);
 705 out:
 706         mutex_unlock(&pwm_lock);
 707 }
 708 EXPORT_SYMBOL_GPL(pwm_put);
 709
 710 static void devm_pwm_release(struct device *dev, void *res)
 711 {
 712         pwm_put(*(struct pwm_device **)res);
 713 }
 714
 715 /**
 716  * devm_pwm_get() - resource managed pwm_get()
 717  * @dev: device for PWM consumer
 718  * @con_id: consumer name
 719  *
 720  * This function performs like pwm_get() but the acquired PWM device will
 721  * automatically be released on driver detach.
 722  */
 723 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
 724 {
 725         struct pwm_device **ptr, *pwm;
 726
 727         ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
 728         if (!ptr)
 729                 return ERR_PTR(-ENOMEM);
 730
 731         pwm = pwm_get(dev, con_id);
 732         if (!IS_ERR(pwm)) {
 733                 *ptr = pwm;
 734                 devres_add(dev, ptr);
 735         } else {
 736                 devres_free(ptr);
 737         }
 738
 739         return pwm;
 740 }
 741 EXPORT_SYMBOL_GPL(devm_pwm_get);
 742
 743 /**
 744  * devm_of_pwm_get() - resource managed of_pwm_get()
 745  * @dev: device for PWM consumer
 746  * @np: device node to get the PWM from
 747  * @con_id: consumer name
 748  *
 749  * This function performs like of_pwm_get() but the acquired PWM device will
 750  * automatically be released on driver detach.
 751  */
 752 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
 753                                    const char *con_id)
 754 {
 755         struct pwm_device **ptr, *pwm;
 756
 757         ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
 758         if (!ptr)
 759                 return ERR_PTR(-ENOMEM);
 760
 761         pwm = of_pwm_get(np, con_id);
 762         if (!IS_ERR(pwm)) {
 763                 *ptr = pwm;
 764                 devres_add(dev, ptr);
 765         } else {
 766                 devres_free(ptr);
 767         }
 768
 769         return pwm;
 770 }
 771 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
 772
 773 static int devm_pwm_match(struct device *dev, void *res, void *data)
 774 {
 775         struct pwm_device **p = res;
 776
 777         if (WARN_ON(!p || !*p))
 778                 return 0;
 779
 780         return *p == data;
 781 }
 782
 783 /**
 784  * devm_pwm_put() - resource managed pwm_put()
 785  * @dev: device for PWM consumer
 786  * @pwm: PWM device
 787  *
 788  * Release a PWM previously allocated using devm_pwm_get(). Calling this
 789  * function is usually not needed because devm-allocated resources are
 790  * automatically released on driver detach.
 791  */
 792 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
 793 {
 794         WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
 795 }
 796 EXPORT_SYMBOL_GPL(devm_pwm_put);
 797
 798 /**
 799   * pwm_can_sleep() - report whether PWM access will sleep
 800   * @pwm: PWM device
 801   *
 802   * It returns true if accessing the PWM can sleep, false otherwise.
 803   */
 804 bool pwm_can_sleep(struct pwm_device *pwm)
 805 {
 806         return pwm->chip->can_sleep;
 807 }
 808 EXPORT_SYMBOL_GPL(pwm_can_sleep);
 809
 810 #ifdef CONFIG_DEBUG_FS
 811 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
 812 {
 813         unsigned int i;
 814
 815         for (i = 0; i < chip->npwm; i++) {
 816                 struct pwm_device *pwm = &chip->pwms[i];
 817
 818                 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
 819
 820                 if (test_bit(PWMF_REQUESTED, &pwm->flags))
 821                         seq_puts(s, " requested");
 822
 823                 if (test_bit(PWMF_ENABLED, &pwm->flags))
 824                         seq_puts(s, " enabled");
 825
 826                 seq_puts(s, "\n");
 827         }
 828 }
 829
 830 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
 831 {
 832         mutex_lock(&pwm_lock);
 833         s->private = "";
 834
 835         return seq_list_start(&pwm_chips, *pos);
 836 }
 837
 838 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
 839 {
 840         s->private = "\n";
 841
 842         return seq_list_next(v, &pwm_chips, pos);
 843 }
 844
 845 static void pwm_seq_stop(struct seq_file *s, void *v)
 846 {
 847         mutex_unlock(&pwm_lock);
 848 }
 849
 850 static int pwm_seq_show(struct seq_file *s, void *v)
 851 {
 852         struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
 853
 854         seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
 855                    chip->dev->bus ? chip->dev->bus->name : "no-bus",
 856                    dev_name(chip->dev), chip->npwm,
 857                    (chip->npwm != 1) ? "s" : "");
 858
 859         if (chip->ops->dbg_show)
 860                 chip->ops->dbg_show(chip, s);
 861         else
 862                 pwm_dbg_show(chip, s);
 863
 864         return 0;
 865 }
 866
 867 static const struct seq_operations pwm_seq_ops = {
 868         .start = pwm_seq_start,
 869         .next = pwm_seq_next,
 870         .stop = pwm_seq_stop,
 871         .show = pwm_seq_show,
 872 };
 873
 874 static int pwm_seq_open(struct inode *inode, struct file *file)
 875 {
 876         return seq_open(file, &pwm_seq_ops);
 877 }
 878
 879 static const struct file_operations pwm_debugfs_ops = {
 880         .owner = THIS_MODULE,
 881         .open = pwm_seq_open,
 882         .read = seq_read,
 883         .llseek = seq_lseek,
 884         .release = seq_release,
 885 };
 886
 887 static int __init pwm_debugfs_init(void)
 888 {
 889         debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
 890                             &pwm_debugfs_ops);
 891
 892         return 0;
 893 }
 894
 895 subsys_initcall(pwm_debugfs_init);
 896 #endif /* CONFIG_DEBUG_FS */