1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Generic pwmlib implementation
5 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
6 * Copyright (C) 2011-2012 Avionic Design GmbH
9 #include <linux/acpi.h>
10 #include <linux/module.h>
11 #include <linux/idr.h>
13 #include <linux/pwm.h>
14 #include <linux/list.h>
15 #include <linux/mutex.h>
16 #include <linux/err.h>
17 #include <linux/slab.h>
18 #include <linux/device.h>
19 #include <linux/debugfs.h>
20 #include <linux/seq_file.h>
22 #include <dt-bindings/pwm/pwm.h>
24 #define CREATE_TRACE_POINTS
25 #include <trace/events/pwm.h>
27 static DEFINE_MUTEX(pwm_lookup_lock);
28 static LIST_HEAD(pwm_lookup_list);
30 /* protects access to pwm_chips */
31 static DEFINE_MUTEX(pwm_lock);
33 static DEFINE_IDR(pwm_chips);
35 static struct pwm_chip *pwmchip_find_by_name(const char *name)
37 struct pwm_chip *chip;
38 unsigned long id, tmp;
43 mutex_lock(&pwm_lock);
45 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
46 const char *chip_name = dev_name(chip->dev);
48 if (chip_name && strcmp(chip_name, name) == 0) {
49 mutex_unlock(&pwm_lock);
54 mutex_unlock(&pwm_lock);
59 static int pwm_device_request(struct pwm_device *pwm, const char *label)
62 struct pwm_chip *chip = pwm->chip;
63 const struct pwm_ops *ops = chip->ops;
65 if (test_bit(PWMF_REQUESTED, &pwm->flags))
68 if (!try_module_get(chip->owner))
72 err = ops->request(chip, pwm);
74 module_put(chip->owner);
81 * Zero-initialize state because most drivers are unaware of
82 * .usage_power. The other members of state are supposed to be
83 * set by lowlevel drivers. We still initialize the whole
84 * structure for simplicity even though this might paper over
85 * faulty implementations of .get_state().
87 struct pwm_state state = { 0, };
89 err = ops->get_state(chip, pwm, &state);
90 trace_pwm_get(pwm, &state, err);
95 if (IS_ENABLED(CONFIG_PWM_DEBUG))
96 pwm->last = pwm->state;
99 set_bit(PWMF_REQUESTED, &pwm->flags);
106 of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
108 struct pwm_device *pwm;
110 if (chip->of_pwm_n_cells < 2)
111 return ERR_PTR(-EINVAL);
113 /* flags in the third cell are optional */
114 if (args->args_count < 2)
115 return ERR_PTR(-EINVAL);
117 if (args->args[0] >= chip->npwm)
118 return ERR_PTR(-EINVAL);
120 pwm = pwm_request_from_chip(chip, args->args[0], NULL);
124 pwm->args.period = args->args[1];
125 pwm->args.polarity = PWM_POLARITY_NORMAL;
127 if (chip->of_pwm_n_cells >= 3) {
128 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
129 pwm->args.polarity = PWM_POLARITY_INVERSED;
134 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
137 of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
139 struct pwm_device *pwm;
141 if (chip->of_pwm_n_cells < 1)
142 return ERR_PTR(-EINVAL);
144 /* validate that one cell is specified, optionally with flags */
145 if (args->args_count != 1 && args->args_count != 2)
146 return ERR_PTR(-EINVAL);
148 pwm = pwm_request_from_chip(chip, 0, NULL);
152 pwm->args.period = args->args[0];
153 pwm->args.polarity = PWM_POLARITY_NORMAL;
155 if (args->args_count == 2 && args->args[1] & PWM_POLARITY_INVERTED)
156 pwm->args.polarity = PWM_POLARITY_INVERSED;
160 EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
162 static void of_pwmchip_add(struct pwm_chip *chip)
164 if (!chip->dev || !chip->dev->of_node)
167 if (!chip->of_xlate) {
170 if (of_property_read_u32(chip->dev->of_node, "#pwm-cells",
174 chip->of_xlate = of_pwm_xlate_with_flags;
175 chip->of_pwm_n_cells = pwm_cells;
178 of_node_get(chip->dev->of_node);
181 static void of_pwmchip_remove(struct pwm_chip *chip)
184 of_node_put(chip->dev->of_node);
187 static bool pwm_ops_check(const struct pwm_chip *chip)
189 const struct pwm_ops *ops = chip->ops;
194 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
196 "Please implement the .get_state() callback\n");
202 * __pwmchip_add() - register a new PWM chip
203 * @chip: the PWM chip to add
204 * @owner: reference to the module providing the chip.
206 * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
207 * pwmchip_add wrapper to do this right.
209 * Returns: 0 on success or a negative error code on failure.
211 int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
216 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
219 if (!pwm_ops_check(chip))
224 chip->pwms = kcalloc(chip->npwm, sizeof(*chip->pwms), GFP_KERNEL);
228 mutex_lock(&pwm_lock);
230 ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
232 mutex_unlock(&pwm_lock);
239 for (i = 0; i < chip->npwm; i++) {
240 struct pwm_device *pwm = &chip->pwms[i];
246 mutex_unlock(&pwm_lock);
248 if (IS_ENABLED(CONFIG_OF))
249 of_pwmchip_add(chip);
251 pwmchip_sysfs_export(chip);
255 EXPORT_SYMBOL_GPL(__pwmchip_add);
258 * pwmchip_remove() - remove a PWM chip
259 * @chip: the PWM chip to remove
261 * Removes a PWM chip.
263 void pwmchip_remove(struct pwm_chip *chip)
265 pwmchip_sysfs_unexport(chip);
267 if (IS_ENABLED(CONFIG_OF))
268 of_pwmchip_remove(chip);
270 mutex_lock(&pwm_lock);
272 idr_remove(&pwm_chips, chip->id);
274 mutex_unlock(&pwm_lock);
278 EXPORT_SYMBOL_GPL(pwmchip_remove);
280 static void devm_pwmchip_remove(void *data)
282 struct pwm_chip *chip = data;
284 pwmchip_remove(chip);
287 int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
291 ret = __pwmchip_add(chip, owner);
295 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
297 EXPORT_SYMBOL_GPL(__devm_pwmchip_add);
300 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
302 * @index: per-chip index of the PWM to request
303 * @label: a literal description string of this PWM
305 * Returns: A pointer to the PWM device at the given index of the given PWM
306 * chip. A negative error code is returned if the index is not valid for the
307 * specified PWM chip or if the PWM device cannot be requested.
309 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
313 struct pwm_device *pwm;
316 if (!chip || index >= chip->npwm)
317 return ERR_PTR(-EINVAL);
319 mutex_lock(&pwm_lock);
320 pwm = &chip->pwms[index];
322 err = pwm_device_request(pwm, label);
326 mutex_unlock(&pwm_lock);
329 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
331 static void pwm_apply_debug(struct pwm_device *pwm,
332 const struct pwm_state *state)
334 struct pwm_state *last = &pwm->last;
335 struct pwm_chip *chip = pwm->chip;
336 struct pwm_state s1 = { 0 }, s2 = { 0 };
339 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
342 /* No reasonable diagnosis possible without .get_state() */
343 if (!chip->ops->get_state)
347 * *state was just applied. Read out the hardware state and do some
351 err = chip->ops->get_state(chip, pwm, &s1);
352 trace_pwm_get(pwm, &s1, err);
354 /* If that failed there isn't much to debug */
358 * The lowlevel driver either ignored .polarity (which is a bug) or as
359 * best effort inverted .polarity and fixed .duty_cycle respectively.
360 * Undo this inversion and fixup for further tests.
362 if (s1.enabled && s1.polarity != state->polarity) {
363 s2.polarity = state->polarity;
364 s2.duty_cycle = s1.period - s1.duty_cycle;
365 s2.period = s1.period;
366 s2.enabled = s1.enabled;
371 if (s2.polarity != state->polarity &&
372 state->duty_cycle < state->period)
373 dev_warn(chip->dev, ".apply ignored .polarity\n");
375 if (state->enabled &&
376 last->polarity == state->polarity &&
377 last->period > s2.period &&
378 last->period <= state->period)
380 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
381 state->period, s2.period, last->period);
383 if (state->enabled && state->period < s2.period)
385 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
386 state->period, s2.period);
388 if (state->enabled &&
389 last->polarity == state->polarity &&
390 last->period == s2.period &&
391 last->duty_cycle > s2.duty_cycle &&
392 last->duty_cycle <= state->duty_cycle)
394 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
395 state->duty_cycle, state->period,
396 s2.duty_cycle, s2.period,
397 last->duty_cycle, last->period);
399 if (state->enabled && state->duty_cycle < s2.duty_cycle)
401 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
402 state->duty_cycle, state->period,
403 s2.duty_cycle, s2.period);
405 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
407 "requested disabled, but yielded enabled with duty > 0\n");
409 /* reapply the state that the driver reported being configured. */
410 err = chip->ops->apply(chip, pwm, &s1);
411 trace_pwm_apply(pwm, &s1, err);
414 dev_err(chip->dev, "failed to reapply current setting\n");
418 *last = (struct pwm_state){ 0 };
419 err = chip->ops->get_state(chip, pwm, last);
420 trace_pwm_get(pwm, last, err);
424 /* reapplication of the current state should give an exact match */
425 if (s1.enabled != last->enabled ||
426 s1.polarity != last->polarity ||
427 (s1.enabled && s1.period != last->period) ||
428 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
430 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
431 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
432 last->enabled, last->polarity, last->duty_cycle,
438 * __pwm_apply() - atomically apply a new state to a PWM device
440 * @state: new state to apply
442 static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
444 struct pwm_chip *chip;
447 if (!pwm || !state || !state->period ||
448 state->duty_cycle > state->period)
453 if (state->period == pwm->state.period &&
454 state->duty_cycle == pwm->state.duty_cycle &&
455 state->polarity == pwm->state.polarity &&
456 state->enabled == pwm->state.enabled &&
457 state->usage_power == pwm->state.usage_power)
460 err = chip->ops->apply(chip, pwm, state);
461 trace_pwm_apply(pwm, state, err);
468 * only do this after pwm->state was applied as some
469 * implementations of .get_state depend on this
471 pwm_apply_debug(pwm, state);
477 * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
478 * Cannot be used in atomic context.
480 * @state: new state to apply
482 int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
487 * Some lowlevel driver's implementations of .apply() make use of
488 * mutexes, also with some drivers only returning when the new
489 * configuration is active calling pwm_apply_might_sleep() from atomic context
490 * is a bad idea. So make it explicit that calling this function might
495 if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
497 * Catch any drivers that have been marked as atomic but
498 * that will sleep anyway.
501 err = __pwm_apply(pwm, state);
504 err = __pwm_apply(pwm, state);
509 EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);
512 * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
513 * Not all PWM devices support this function, check with pwm_might_sleep().
515 * @state: new state to apply
517 int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
519 WARN_ONCE(!pwm->chip->atomic,
520 "sleeping PWM driver used in atomic context\n");
522 return __pwm_apply(pwm, state);
524 EXPORT_SYMBOL_GPL(pwm_apply_atomic);
527 * pwm_capture() - capture and report a PWM signal
529 * @result: structure to fill with capture result
530 * @timeout: time to wait, in milliseconds, before giving up on capture
532 * Returns: 0 on success or a negative error code on failure.
534 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
535 unsigned long timeout)
539 if (!pwm || !pwm->chip->ops)
542 if (!pwm->chip->ops->capture)
545 mutex_lock(&pwm_lock);
546 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
547 mutex_unlock(&pwm_lock);
551 EXPORT_SYMBOL_GPL(pwm_capture);
554 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
557 * This function will adjust the PWM config to the PWM arguments provided
558 * by the DT or PWM lookup table. This is particularly useful to adapt
559 * the bootloader config to the Linux one.
561 int pwm_adjust_config(struct pwm_device *pwm)
563 struct pwm_state state;
564 struct pwm_args pargs;
566 pwm_get_args(pwm, &pargs);
567 pwm_get_state(pwm, &state);
570 * If the current period is zero it means that either the PWM driver
571 * does not support initial state retrieval or the PWM has not yet
574 * In either case, we setup the new period and polarity, and assign a
578 state.duty_cycle = 0;
579 state.period = pargs.period;
580 state.polarity = pargs.polarity;
582 return pwm_apply_might_sleep(pwm, &state);
586 * Adjust the PWM duty cycle/period based on the period value provided
589 if (pargs.period != state.period) {
590 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
592 do_div(dutycycle, state.period);
593 state.duty_cycle = dutycycle;
594 state.period = pargs.period;
598 * If the polarity changed, we should also change the duty cycle.
600 if (pargs.polarity != state.polarity) {
601 state.polarity = pargs.polarity;
602 state.duty_cycle = state.period - state.duty_cycle;
605 return pwm_apply_might_sleep(pwm, &state);
607 EXPORT_SYMBOL_GPL(pwm_adjust_config);
609 static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
611 struct pwm_chip *chip;
612 unsigned long id, tmp;
614 mutex_lock(&pwm_lock);
616 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
617 if (chip->dev && device_match_fwnode(chip->dev, fwnode)) {
618 mutex_unlock(&pwm_lock);
622 mutex_unlock(&pwm_lock);
624 return ERR_PTR(-EPROBE_DEFER);
627 static struct device_link *pwm_device_link_add(struct device *dev,
628 struct pwm_device *pwm)
630 struct device_link *dl;
634 * No device for the PWM consumer has been provided. It may
635 * impact the PM sequence ordering: the PWM supplier may get
636 * suspended before the consumer.
638 dev_warn(pwm->chip->dev,
639 "No consumer device specified to create a link to\n");
643 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
645 dev_err(dev, "failed to create device link to %s\n",
646 dev_name(pwm->chip->dev));
647 return ERR_PTR(-EINVAL);
654 * of_pwm_get() - request a PWM via the PWM framework
655 * @dev: device for PWM consumer
656 * @np: device node to get the PWM from
657 * @con_id: consumer name
659 * Returns the PWM device parsed from the phandle and index specified in the
660 * "pwms" property of a device tree node or a negative error-code on failure.
661 * Values parsed from the device tree are stored in the returned PWM device
664 * If con_id is NULL, the first PWM device listed in the "pwms" property will
665 * be requested. Otherwise the "pwm-names" property is used to do a reverse
666 * lookup of the PWM index. This also means that the "pwm-names" property
667 * becomes mandatory for devices that look up the PWM device via the con_id
670 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
671 * error code on failure.
673 static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
676 struct pwm_device *pwm = NULL;
677 struct of_phandle_args args;
678 struct device_link *dl;
679 struct pwm_chip *chip;
684 index = of_property_match_string(np, "pwm-names", con_id);
686 return ERR_PTR(index);
689 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
692 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
696 chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
698 if (PTR_ERR(chip) != -EPROBE_DEFER)
699 pr_err("%s(): PWM chip not found\n", __func__);
701 pwm = ERR_CAST(chip);
705 pwm = chip->of_xlate(chip, &args);
709 dl = pwm_device_link_add(dev, pwm);
711 /* of_xlate ended up calling pwm_request_from_chip() */
718 * If a consumer name was not given, try to look it up from the
719 * "pwm-names" property if it exists. Otherwise use the name of
720 * the user device node.
723 err = of_property_read_string_index(np, "pwm-names", index,
732 of_node_put(args.np);
738 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
739 * @fwnode: firmware node to get the "pwms" property from
741 * Returns the PWM device parsed from the fwnode and index specified in the
742 * "pwms" property or a negative error-code on failure.
743 * Values parsed from the device tree are stored in the returned PWM device
746 * This is analogous to of_pwm_get() except con_id is not yet supported.
747 * ACPI entries must look like
748 * Package () {"pwms", Package ()
749 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
751 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
752 * error code on failure.
754 static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
756 struct pwm_device *pwm;
757 struct fwnode_reference_args args;
758 struct pwm_chip *chip;
761 memset(&args, 0, sizeof(args));
763 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
768 return ERR_PTR(-EPROTO);
770 chip = fwnode_to_pwmchip(args.fwnode);
772 return ERR_CAST(chip);
774 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
778 pwm->args.period = args.args[1];
779 pwm->args.polarity = PWM_POLARITY_NORMAL;
781 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
782 pwm->args.polarity = PWM_POLARITY_INVERSED;
788 * pwm_add_table() - register PWM device consumers
789 * @table: array of consumers to register
790 * @num: number of consumers in table
792 void pwm_add_table(struct pwm_lookup *table, size_t num)
794 mutex_lock(&pwm_lookup_lock);
797 list_add_tail(&table->list, &pwm_lookup_list);
801 mutex_unlock(&pwm_lookup_lock);
805 * pwm_remove_table() - unregister PWM device consumers
806 * @table: array of consumers to unregister
807 * @num: number of consumers in table
809 void pwm_remove_table(struct pwm_lookup *table, size_t num)
811 mutex_lock(&pwm_lookup_lock);
814 list_del(&table->list);
818 mutex_unlock(&pwm_lookup_lock);
822 * pwm_get() - look up and request a PWM device
823 * @dev: device for PWM consumer
824 * @con_id: consumer name
826 * Lookup is first attempted using DT. If the device was not instantiated from
827 * a device tree, a PWM chip and a relative index is looked up via a table
828 * supplied by board setup code (see pwm_add_table()).
830 * Once a PWM chip has been found the specified PWM device will be requested
831 * and is ready to be used.
833 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
834 * error code on failure.
836 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
838 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
839 const char *dev_id = dev ? dev_name(dev) : NULL;
840 struct pwm_device *pwm;
841 struct pwm_chip *chip;
842 struct device_link *dl;
843 unsigned int best = 0;
844 struct pwm_lookup *p, *chosen = NULL;
848 /* look up via DT first */
849 if (is_of_node(fwnode))
850 return of_pwm_get(dev, to_of_node(fwnode), con_id);
852 /* then lookup via ACPI */
853 if (is_acpi_node(fwnode)) {
854 pwm = acpi_pwm_get(fwnode);
855 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
860 * We look up the provider in the static table typically provided by
861 * board setup code. We first try to lookup the consumer device by
862 * name. If the consumer device was passed in as NULL or if no match
863 * was found, we try to find the consumer by directly looking it up
866 * If a match is found, the provider PWM chip is looked up by name
867 * and a PWM device is requested using the PWM device per-chip index.
869 * The lookup algorithm was shamelessly taken from the clock
872 * We do slightly fuzzy matching here:
873 * An entry with a NULL ID is assumed to be a wildcard.
874 * If an entry has a device ID, it must match
875 * If an entry has a connection ID, it must match
876 * Then we take the most specific entry - with the following order
877 * of precedence: dev+con > dev only > con only.
879 mutex_lock(&pwm_lookup_lock);
881 list_for_each_entry(p, &pwm_lookup_list, list) {
885 if (!dev_id || strcmp(p->dev_id, dev_id))
892 if (!con_id || strcmp(p->con_id, con_id))
908 mutex_unlock(&pwm_lookup_lock);
911 return ERR_PTR(-ENODEV);
913 chip = pwmchip_find_by_name(chosen->provider);
916 * If the lookup entry specifies a module, load the module and retry
917 * the PWM chip lookup. This can be used to work around driver load
918 * ordering issues if driver's can't be made to properly support the
919 * deferred probe mechanism.
921 if (!chip && chosen->module) {
922 err = request_module(chosen->module);
924 chip = pwmchip_find_by_name(chosen->provider);
928 return ERR_PTR(-EPROBE_DEFER);
930 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
934 dl = pwm_device_link_add(dev, pwm);
940 pwm->args.period = chosen->period;
941 pwm->args.polarity = chosen->polarity;
945 EXPORT_SYMBOL_GPL(pwm_get);
948 * pwm_put() - release a PWM device
951 void pwm_put(struct pwm_device *pwm)
956 mutex_lock(&pwm_lock);
958 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
959 pr_warn("PWM device already freed\n");
963 if (pwm->chip->ops->free)
964 pwm->chip->ops->free(pwm->chip, pwm);
968 module_put(pwm->chip->owner);
970 mutex_unlock(&pwm_lock);
972 EXPORT_SYMBOL_GPL(pwm_put);
974 static void devm_pwm_release(void *pwm)
980 * devm_pwm_get() - resource managed pwm_get()
981 * @dev: device for PWM consumer
982 * @con_id: consumer name
984 * This function performs like pwm_get() but the acquired PWM device will
985 * automatically be released on driver detach.
987 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
988 * error code on failure.
990 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
992 struct pwm_device *pwm;
995 pwm = pwm_get(dev, con_id);
999 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1001 return ERR_PTR(ret);
1005 EXPORT_SYMBOL_GPL(devm_pwm_get);
1008 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1009 * @dev: device for PWM consumer
1010 * @fwnode: firmware node to get the PWM from
1011 * @con_id: consumer name
1013 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1014 * acpi_pwm_get() for a detailed description.
1016 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1017 * error code on failure.
1019 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1020 struct fwnode_handle *fwnode,
1023 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1026 if (is_of_node(fwnode))
1027 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1028 else if (is_acpi_node(fwnode))
1029 pwm = acpi_pwm_get(fwnode);
1033 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1035 return ERR_PTR(ret);
1039 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1041 #ifdef CONFIG_DEBUG_FS
1042 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1046 for (i = 0; i < chip->npwm; i++) {
1047 struct pwm_device *pwm = &chip->pwms[i];
1048 struct pwm_state state;
1050 pwm_get_state(pwm, &state);
1052 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1054 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1055 seq_puts(s, " requested");
1058 seq_puts(s, " enabled");
1060 seq_printf(s, " period: %llu ns", state.period);
1061 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1062 seq_printf(s, " polarity: %s",
1063 state.polarity ? "inverse" : "normal");
1065 if (state.usage_power)
1066 seq_puts(s, " usage_power");
1072 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1074 unsigned long id = *pos;
1077 mutex_lock(&pwm_lock);
1080 ret = idr_get_next_ul(&pwm_chips, &id);
1085 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1087 unsigned long id = *pos + 1;
1092 ret = idr_get_next_ul(&pwm_chips, &id);
1097 static void pwm_seq_stop(struct seq_file *s, void *v)
1099 mutex_unlock(&pwm_lock);
1102 static int pwm_seq_show(struct seq_file *s, void *v)
1104 struct pwm_chip *chip = v;
1106 seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n",
1107 (char *)s->private, chip->id,
1108 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1109 dev_name(chip->dev), chip->npwm,
1110 (chip->npwm != 1) ? "s" : "");
1112 pwm_dbg_show(chip, s);
1117 static const struct seq_operations pwm_debugfs_sops = {
1118 .start = pwm_seq_start,
1119 .next = pwm_seq_next,
1120 .stop = pwm_seq_stop,
1121 .show = pwm_seq_show,
1124 DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1126 static int __init pwm_debugfs_init(void)
1128 debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1132 subsys_initcall(pwm_debugfs_init);
1133 #endif /* CONFIG_DEBUG_FS */