drivers/pwm/core.c

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

DEFINITIONS
