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/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>
21 #include <dt-bindings/pwm/pwm.h>
23 #define CREATE_TRACE_POINTS
24 #include <trace/events/pwm.h>
28 static DEFINE_MUTEX(pwm_lookup_lock);
29 static LIST_HEAD(pwm_lookup_list);
30 static DEFINE_MUTEX(pwm_lock);
31 static LIST_HEAD(pwm_chips);
32 static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
33 static RADIX_TREE(pwm_tree, GFP_KERNEL);
35 static struct pwm_device *pwm_to_device(unsigned int pwm)
37 return radix_tree_lookup(&pwm_tree, pwm);
40 static int alloc_pwms(unsigned int count)
44 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, 0,
47 if (start + count > MAX_PWMS)
53 static void free_pwms(struct pwm_chip *chip)
57 for (i = 0; i < chip->npwm; i++) {
58 struct pwm_device *pwm = &chip->pwms[i];
60 radix_tree_delete(&pwm_tree, pwm->pwm);
63 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
69 static struct pwm_chip *pwmchip_find_by_name(const char *name)
71 struct pwm_chip *chip;
76 mutex_lock(&pwm_lock);
78 list_for_each_entry(chip, &pwm_chips, list) {
79 const char *chip_name = dev_name(chip->dev);
81 if (chip_name && strcmp(chip_name, name) == 0) {
82 mutex_unlock(&pwm_lock);
87 mutex_unlock(&pwm_lock);
92 static int pwm_device_request(struct pwm_device *pwm, const char *label)
96 if (test_bit(PWMF_REQUESTED, &pwm->flags))
99 if (!try_module_get(pwm->chip->ops->owner))
102 if (pwm->chip->ops->request) {
103 err = pwm->chip->ops->request(pwm->chip, pwm);
105 module_put(pwm->chip->ops->owner);
110 if (pwm->chip->ops->get_state) {
111 pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
112 trace_pwm_get(pwm, &pwm->state);
114 if (IS_ENABLED(CONFIG_PWM_DEBUG))
115 pwm->last = pwm->state;
118 set_bit(PWMF_REQUESTED, &pwm->flags);
125 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
127 struct pwm_device *pwm;
129 if (pc->of_pwm_n_cells < 2)
130 return ERR_PTR(-EINVAL);
132 /* flags in the third cell are optional */
133 if (args->args_count < 2)
134 return ERR_PTR(-EINVAL);
136 if (args->args[0] >= pc->npwm)
137 return ERR_PTR(-EINVAL);
139 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
143 pwm->args.period = args->args[1];
144 pwm->args.polarity = PWM_POLARITY_NORMAL;
146 if (pc->of_pwm_n_cells >= 3) {
147 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
148 pwm->args.polarity = PWM_POLARITY_INVERSED;
153 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
155 static void of_pwmchip_add(struct pwm_chip *chip)
157 if (!chip->dev || !chip->dev->of_node)
160 if (!chip->of_xlate) {
161 chip->of_xlate = of_pwm_xlate_with_flags;
162 chip->of_pwm_n_cells = 2;
165 of_node_get(chip->dev->of_node);
168 static void of_pwmchip_remove(struct pwm_chip *chip)
171 of_node_put(chip->dev->of_node);
175 * pwm_set_chip_data() - set private chip data for a PWM
177 * @data: pointer to chip-specific data
179 * Returns: 0 on success or a negative error code on failure.
181 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
186 pwm->chip_data = data;
190 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
193 * pwm_get_chip_data() - get private chip data for a PWM
196 * Returns: A pointer to the chip-private data for the PWM device.
198 void *pwm_get_chip_data(struct pwm_device *pwm)
200 return pwm ? pwm->chip_data : NULL;
202 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
204 static bool pwm_ops_check(const struct pwm_chip *chip)
207 const struct pwm_ops *ops = chip->ops;
209 /* driver supports legacy, non-atomic operation */
210 if (ops->config && ops->enable && ops->disable) {
211 if (IS_ENABLED(CONFIG_PWM_DEBUG))
213 "Driver needs updating to atomic API\n");
221 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
223 "Please implement the .get_state() callback\n");
229 * pwmchip_add() - register a new PWM chip
230 * @chip: the PWM chip to add
232 * Register a new PWM chip.
234 * Returns: 0 on success or a negative error code on failure.
236 int pwmchip_add(struct pwm_chip *chip)
238 struct pwm_device *pwm;
242 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
245 if (!pwm_ops_check(chip))
248 mutex_lock(&pwm_lock);
250 ret = alloc_pwms(chip->npwm);
256 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
262 for (i = 0; i < chip->npwm; i++) {
263 pwm = &chip->pwms[i];
266 pwm->pwm = chip->base + i;
269 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
272 bitmap_set(allocated_pwms, chip->base, chip->npwm);
274 INIT_LIST_HEAD(&chip->list);
275 list_add(&chip->list, &pwm_chips);
279 if (IS_ENABLED(CONFIG_OF))
280 of_pwmchip_add(chip);
283 mutex_unlock(&pwm_lock);
286 pwmchip_sysfs_export(chip);
290 EXPORT_SYMBOL_GPL(pwmchip_add);
293 * pwmchip_remove() - remove a PWM chip
294 * @chip: the PWM chip to remove
296 * Removes a PWM chip. This function may return busy if the PWM chip provides
297 * a PWM device that is still requested.
299 * Returns: 0 on success or a negative error code on failure.
301 int pwmchip_remove(struct pwm_chip *chip)
306 pwmchip_sysfs_unexport(chip);
308 mutex_lock(&pwm_lock);
310 for (i = 0; i < chip->npwm; i++) {
311 struct pwm_device *pwm = &chip->pwms[i];
313 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
319 list_del_init(&chip->list);
321 if (IS_ENABLED(CONFIG_OF))
322 of_pwmchip_remove(chip);
327 mutex_unlock(&pwm_lock);
330 EXPORT_SYMBOL_GPL(pwmchip_remove);
333 * pwm_request() - request a PWM device
334 * @pwm: global PWM device index
335 * @label: PWM device label
337 * This function is deprecated, use pwm_get() instead.
339 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
342 struct pwm_device *pwm_request(int pwm, const char *label)
344 struct pwm_device *dev;
347 if (pwm < 0 || pwm >= MAX_PWMS)
348 return ERR_PTR(-EINVAL);
350 mutex_lock(&pwm_lock);
352 dev = pwm_to_device(pwm);
354 dev = ERR_PTR(-EPROBE_DEFER);
358 err = pwm_device_request(dev, label);
363 mutex_unlock(&pwm_lock);
367 EXPORT_SYMBOL_GPL(pwm_request);
370 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
372 * @index: per-chip index of the PWM to request
373 * @label: a literal description string of this PWM
375 * Returns: A pointer to the PWM device at the given index of the given PWM
376 * chip. A negative error code is returned if the index is not valid for the
377 * specified PWM chip or if the PWM device cannot be requested.
379 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
383 struct pwm_device *pwm;
386 if (!chip || index >= chip->npwm)
387 return ERR_PTR(-EINVAL);
389 mutex_lock(&pwm_lock);
390 pwm = &chip->pwms[index];
392 err = pwm_device_request(pwm, label);
396 mutex_unlock(&pwm_lock);
399 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
402 * pwm_free() - free a PWM device
405 * This function is deprecated, use pwm_put() instead.
407 void pwm_free(struct pwm_device *pwm)
411 EXPORT_SYMBOL_GPL(pwm_free);
413 static void pwm_apply_state_debug(struct pwm_device *pwm,
414 const struct pwm_state *state)
416 struct pwm_state *last = &pwm->last;
417 struct pwm_chip *chip = pwm->chip;
418 struct pwm_state s1, s2;
421 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
424 /* No reasonable diagnosis possible without .get_state() */
425 if (!chip->ops->get_state)
429 * *state was just applied. Read out the hardware state and do some
433 chip->ops->get_state(chip, pwm, &s1);
434 trace_pwm_get(pwm, &s1);
437 * The lowlevel driver either ignored .polarity (which is a bug) or as
438 * best effort inverted .polarity and fixed .duty_cycle respectively.
439 * Undo this inversion and fixup for further tests.
441 if (s1.enabled && s1.polarity != state->polarity) {
442 s2.polarity = state->polarity;
443 s2.duty_cycle = s1.period - s1.duty_cycle;
444 s2.period = s1.period;
445 s2.enabled = s1.enabled;
450 if (s2.polarity != state->polarity &&
451 state->duty_cycle < state->period)
452 dev_warn(chip->dev, ".apply ignored .polarity\n");
454 if (state->enabled &&
455 last->polarity == state->polarity &&
456 last->period > s2.period &&
457 last->period <= state->period)
459 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
460 state->period, s2.period, last->period);
462 if (state->enabled && state->period < s2.period)
464 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
465 state->period, s2.period);
467 if (state->enabled &&
468 last->polarity == state->polarity &&
469 last->period == s2.period &&
470 last->duty_cycle > s2.duty_cycle &&
471 last->duty_cycle <= state->duty_cycle)
473 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
474 state->duty_cycle, state->period,
475 s2.duty_cycle, s2.period,
476 last->duty_cycle, last->period);
478 if (state->enabled && state->duty_cycle < s2.duty_cycle)
480 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
481 state->duty_cycle, state->period,
482 s2.duty_cycle, s2.period);
484 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
486 "requested disabled, but yielded enabled with duty > 0\n");
488 /* reapply the state that the driver reported being configured. */
489 err = chip->ops->apply(chip, pwm, &s1);
492 dev_err(chip->dev, "failed to reapply current setting\n");
496 trace_pwm_apply(pwm, &s1);
498 chip->ops->get_state(chip, pwm, last);
499 trace_pwm_get(pwm, last);
501 /* reapplication of the current state should give an exact match */
502 if (s1.enabled != last->enabled ||
503 s1.polarity != last->polarity ||
504 (s1.enabled && s1.period != last->period) ||
505 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
507 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
508 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
509 last->enabled, last->polarity, last->duty_cycle,
515 * pwm_apply_state() - atomically apply a new state to a PWM device
517 * @state: new state to apply
519 int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
521 struct pwm_chip *chip;
524 if (!pwm || !state || !state->period ||
525 state->duty_cycle > state->period)
530 if (state->period == pwm->state.period &&
531 state->duty_cycle == pwm->state.duty_cycle &&
532 state->polarity == pwm->state.polarity &&
533 state->enabled == pwm->state.enabled)
536 if (chip->ops->apply) {
537 err = chip->ops->apply(chip, pwm, state);
541 trace_pwm_apply(pwm, state);
546 * only do this after pwm->state was applied as some
547 * implementations of .get_state depend on this
549 pwm_apply_state_debug(pwm, state);
552 * FIXME: restore the initial state in case of error.
554 if (state->polarity != pwm->state.polarity) {
555 if (!chip->ops->set_polarity)
559 * Changing the polarity of a running PWM is
560 * only allowed when the PWM driver implements
563 if (pwm->state.enabled) {
564 chip->ops->disable(chip, pwm);
565 pwm->state.enabled = false;
568 err = chip->ops->set_polarity(chip, pwm,
573 pwm->state.polarity = state->polarity;
576 if (state->period != pwm->state.period ||
577 state->duty_cycle != pwm->state.duty_cycle) {
578 err = chip->ops->config(pwm->chip, pwm,
584 pwm->state.duty_cycle = state->duty_cycle;
585 pwm->state.period = state->period;
588 if (state->enabled != pwm->state.enabled) {
589 if (state->enabled) {
590 err = chip->ops->enable(chip, pwm);
594 chip->ops->disable(chip, pwm);
597 pwm->state.enabled = state->enabled;
603 EXPORT_SYMBOL_GPL(pwm_apply_state);
606 * pwm_capture() - capture and report a PWM signal
608 * @result: structure to fill with capture result
609 * @timeout: time to wait, in milliseconds, before giving up on capture
611 * Returns: 0 on success or a negative error code on failure.
613 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
614 unsigned long timeout)
618 if (!pwm || !pwm->chip->ops)
621 if (!pwm->chip->ops->capture)
624 mutex_lock(&pwm_lock);
625 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
626 mutex_unlock(&pwm_lock);
630 EXPORT_SYMBOL_GPL(pwm_capture);
633 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
636 * This function will adjust the PWM config to the PWM arguments provided
637 * by the DT or PWM lookup table. This is particularly useful to adapt
638 * the bootloader config to the Linux one.
640 int pwm_adjust_config(struct pwm_device *pwm)
642 struct pwm_state state;
643 struct pwm_args pargs;
645 pwm_get_args(pwm, &pargs);
646 pwm_get_state(pwm, &state);
649 * If the current period is zero it means that either the PWM driver
650 * does not support initial state retrieval or the PWM has not yet
653 * In either case, we setup the new period and polarity, and assign a
657 state.duty_cycle = 0;
658 state.period = pargs.period;
659 state.polarity = pargs.polarity;
661 return pwm_apply_state(pwm, &state);
665 * Adjust the PWM duty cycle/period based on the period value provided
668 if (pargs.period != state.period) {
669 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
671 do_div(dutycycle, state.period);
672 state.duty_cycle = dutycycle;
673 state.period = pargs.period;
677 * If the polarity changed, we should also change the duty cycle.
679 if (pargs.polarity != state.polarity) {
680 state.polarity = pargs.polarity;
681 state.duty_cycle = state.period - state.duty_cycle;
684 return pwm_apply_state(pwm, &state);
686 EXPORT_SYMBOL_GPL(pwm_adjust_config);
688 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
690 struct pwm_chip *chip;
692 mutex_lock(&pwm_lock);
694 list_for_each_entry(chip, &pwm_chips, list)
695 if (chip->dev && chip->dev->of_node == np) {
696 mutex_unlock(&pwm_lock);
700 mutex_unlock(&pwm_lock);
702 return ERR_PTR(-EPROBE_DEFER);
705 static struct device_link *pwm_device_link_add(struct device *dev,
706 struct pwm_device *pwm)
708 struct device_link *dl;
712 * No device for the PWM consumer has been provided. It may
713 * impact the PM sequence ordering: the PWM supplier may get
714 * suspended before the consumer.
716 dev_warn(pwm->chip->dev,
717 "No consumer device specified to create a link to\n");
721 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
723 dev_err(dev, "failed to create device link to %s\n",
724 dev_name(pwm->chip->dev));
725 return ERR_PTR(-EINVAL);
732 * of_pwm_get() - request a PWM via the PWM framework
733 * @dev: device for PWM consumer
734 * @np: device node to get the PWM from
735 * @con_id: consumer name
737 * Returns the PWM device parsed from the phandle and index specified in the
738 * "pwms" property of a device tree node or a negative error-code on failure.
739 * Values parsed from the device tree are stored in the returned PWM device
742 * If con_id is NULL, the first PWM device listed in the "pwms" property will
743 * be requested. Otherwise the "pwm-names" property is used to do a reverse
744 * lookup of the PWM index. This also means that the "pwm-names" property
745 * becomes mandatory for devices that look up the PWM device via the con_id
748 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
749 * error code on failure.
751 struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
754 struct pwm_device *pwm = NULL;
755 struct of_phandle_args args;
756 struct device_link *dl;
762 index = of_property_match_string(np, "pwm-names", con_id);
764 return ERR_PTR(index);
767 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
770 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
774 pc = of_node_to_pwmchip(args.np);
776 if (PTR_ERR(pc) != -EPROBE_DEFER)
777 pr_err("%s(): PWM chip not found\n", __func__);
783 pwm = pc->of_xlate(pc, &args);
787 dl = pwm_device_link_add(dev, pwm);
789 /* of_xlate ended up calling pwm_request_from_chip() */
796 * If a consumer name was not given, try to look it up from the
797 * "pwm-names" property if it exists. Otherwise use the name of
798 * the user device node.
801 err = of_property_read_string_index(np, "pwm-names", index,
810 of_node_put(args.np);
814 EXPORT_SYMBOL_GPL(of_pwm_get);
816 #if IS_ENABLED(CONFIG_ACPI)
817 static struct pwm_chip *device_to_pwmchip(struct device *dev)
819 struct pwm_chip *chip;
821 mutex_lock(&pwm_lock);
823 list_for_each_entry(chip, &pwm_chips, list) {
824 struct acpi_device *adev = ACPI_COMPANION(chip->dev);
826 if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
827 mutex_unlock(&pwm_lock);
832 mutex_unlock(&pwm_lock);
834 return ERR_PTR(-EPROBE_DEFER);
839 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
840 * @fwnode: firmware node to get the "pwm" property from
842 * Returns the PWM device parsed from the fwnode and index specified in the
843 * "pwms" property or a negative error-code on failure.
844 * Values parsed from the device tree are stored in the returned PWM device
847 * This is analogous to of_pwm_get() except con_id is not yet supported.
848 * ACPI entries must look like
849 * Package () {"pwms", Package ()
850 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
852 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
853 * error code on failure.
855 static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
857 struct pwm_device *pwm = ERR_PTR(-ENODEV);
858 #if IS_ENABLED(CONFIG_ACPI)
859 struct fwnode_reference_args args;
860 struct acpi_device *acpi;
861 struct pwm_chip *chip;
864 memset(&args, 0, sizeof(args));
866 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
870 acpi = to_acpi_device_node(args.fwnode);
872 return ERR_PTR(-EINVAL);
875 return ERR_PTR(-EPROTO);
877 chip = device_to_pwmchip(&acpi->dev);
879 return ERR_CAST(chip);
881 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
885 pwm->args.period = args.args[1];
886 pwm->args.polarity = PWM_POLARITY_NORMAL;
888 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
889 pwm->args.polarity = PWM_POLARITY_INVERSED;
896 * pwm_add_table() - register PWM device consumers
897 * @table: array of consumers to register
898 * @num: number of consumers in table
900 void pwm_add_table(struct pwm_lookup *table, size_t num)
902 mutex_lock(&pwm_lookup_lock);
905 list_add_tail(&table->list, &pwm_lookup_list);
909 mutex_unlock(&pwm_lookup_lock);
913 * pwm_remove_table() - unregister PWM device consumers
914 * @table: array of consumers to unregister
915 * @num: number of consumers in table
917 void pwm_remove_table(struct pwm_lookup *table, size_t num)
919 mutex_lock(&pwm_lookup_lock);
922 list_del(&table->list);
926 mutex_unlock(&pwm_lookup_lock);
930 * pwm_get() - look up and request a PWM device
931 * @dev: device for PWM consumer
932 * @con_id: consumer name
934 * Lookup is first attempted using DT. If the device was not instantiated from
935 * a device tree, a PWM chip and a relative index is looked up via a table
936 * supplied by board setup code (see pwm_add_table()).
938 * Once a PWM chip has been found the specified PWM device will be requested
939 * and is ready to be used.
941 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
942 * error code on failure.
944 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
946 const char *dev_id = dev ? dev_name(dev) : NULL;
947 struct pwm_device *pwm;
948 struct pwm_chip *chip;
949 struct device_link *dl;
950 unsigned int best = 0;
951 struct pwm_lookup *p, *chosen = NULL;
955 /* look up via DT first */
956 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
957 return of_pwm_get(dev, dev->of_node, con_id);
959 /* then lookup via ACPI */
960 if (dev && is_acpi_node(dev->fwnode)) {
961 pwm = acpi_pwm_get(dev->fwnode);
962 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
967 * We look up the provider in the static table typically provided by
968 * board setup code. We first try to lookup the consumer device by
969 * name. If the consumer device was passed in as NULL or if no match
970 * was found, we try to find the consumer by directly looking it up
973 * If a match is found, the provider PWM chip is looked up by name
974 * and a PWM device is requested using the PWM device per-chip index.
976 * The lookup algorithm was shamelessly taken from the clock
979 * We do slightly fuzzy matching here:
980 * An entry with a NULL ID is assumed to be a wildcard.
981 * If an entry has a device ID, it must match
982 * If an entry has a connection ID, it must match
983 * Then we take the most specific entry - with the following order
984 * of precedence: dev+con > dev only > con only.
986 mutex_lock(&pwm_lookup_lock);
988 list_for_each_entry(p, &pwm_lookup_list, list) {
992 if (!dev_id || strcmp(p->dev_id, dev_id))
999 if (!con_id || strcmp(p->con_id, con_id))
1015 mutex_unlock(&pwm_lookup_lock);
1018 return ERR_PTR(-ENODEV);
1020 chip = pwmchip_find_by_name(chosen->provider);
1023 * If the lookup entry specifies a module, load the module and retry
1024 * the PWM chip lookup. This can be used to work around driver load
1025 * ordering issues if driver's can't be made to properly support the
1026 * deferred probe mechanism.
1028 if (!chip && chosen->module) {
1029 err = request_module(chosen->module);
1031 chip = pwmchip_find_by_name(chosen->provider);
1035 return ERR_PTR(-EPROBE_DEFER);
1037 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1041 dl = pwm_device_link_add(dev, pwm);
1044 return ERR_CAST(dl);
1047 pwm->args.period = chosen->period;
1048 pwm->args.polarity = chosen->polarity;
1052 EXPORT_SYMBOL_GPL(pwm_get);
1055 * pwm_put() - release a PWM device
1058 void pwm_put(struct pwm_device *pwm)
1063 mutex_lock(&pwm_lock);
1065 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1066 pr_warn("PWM device already freed\n");
1070 if (pwm->chip->ops->free)
1071 pwm->chip->ops->free(pwm->chip, pwm);
1073 pwm_set_chip_data(pwm, NULL);
1076 module_put(pwm->chip->ops->owner);
1078 mutex_unlock(&pwm_lock);
1080 EXPORT_SYMBOL_GPL(pwm_put);
1082 static void devm_pwm_release(struct device *dev, void *res)
1084 pwm_put(*(struct pwm_device **)res);
1088 * devm_pwm_get() - resource managed pwm_get()
1089 * @dev: device for PWM consumer
1090 * @con_id: consumer name
1092 * This function performs like pwm_get() but the acquired PWM device will
1093 * automatically be released on driver detach.
1095 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1096 * error code on failure.
1098 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1100 struct pwm_device **ptr, *pwm;
1102 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1104 return ERR_PTR(-ENOMEM);
1106 pwm = pwm_get(dev, con_id);
1109 devres_add(dev, ptr);
1116 EXPORT_SYMBOL_GPL(devm_pwm_get);
1119 * devm_of_pwm_get() - resource managed of_pwm_get()
1120 * @dev: device for PWM consumer
1121 * @np: device node to get the PWM from
1122 * @con_id: consumer name
1124 * This function performs like of_pwm_get() but the acquired PWM device will
1125 * automatically be released on driver detach.
1127 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1128 * error code on failure.
1130 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
1133 struct pwm_device **ptr, *pwm;
1135 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1137 return ERR_PTR(-ENOMEM);
1139 pwm = of_pwm_get(dev, np, con_id);
1142 devres_add(dev, ptr);
1149 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
1152 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1153 * @dev: device for PWM consumer
1154 * @fwnode: firmware node to get the PWM from
1155 * @con_id: consumer name
1157 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1158 * acpi_pwm_get() for a detailed description.
1160 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1161 * error code on failure.
1163 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1164 struct fwnode_handle *fwnode,
1167 struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV);
1169 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1171 return ERR_PTR(-ENOMEM);
1173 if (is_of_node(fwnode))
1174 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1175 else if (is_acpi_node(fwnode))
1176 pwm = acpi_pwm_get(fwnode);
1180 devres_add(dev, ptr);
1187 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1189 static int devm_pwm_match(struct device *dev, void *res, void *data)
1191 struct pwm_device **p = res;
1193 if (WARN_ON(!p || !*p))
1200 * devm_pwm_put() - resource managed pwm_put()
1201 * @dev: device for PWM consumer
1204 * Release a PWM previously allocated using devm_pwm_get(). Calling this
1205 * function is usually not needed because devm-allocated resources are
1206 * automatically released on driver detach.
1208 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
1210 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
1212 EXPORT_SYMBOL_GPL(devm_pwm_put);
1214 #ifdef CONFIG_DEBUG_FS
1215 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1219 for (i = 0; i < chip->npwm; i++) {
1220 struct pwm_device *pwm = &chip->pwms[i];
1221 struct pwm_state state;
1223 pwm_get_state(pwm, &state);
1225 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1227 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1228 seq_puts(s, " requested");
1231 seq_puts(s, " enabled");
1233 seq_printf(s, " period: %llu ns", state.period);
1234 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1235 seq_printf(s, " polarity: %s",
1236 state.polarity ? "inverse" : "normal");
1242 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1244 mutex_lock(&pwm_lock);
1247 return seq_list_start(&pwm_chips, *pos);
1250 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1254 return seq_list_next(v, &pwm_chips, pos);
1257 static void pwm_seq_stop(struct seq_file *s, void *v)
1259 mutex_unlock(&pwm_lock);
1262 static int pwm_seq_show(struct seq_file *s, void *v)
1264 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1266 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1267 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1268 dev_name(chip->dev), chip->npwm,
1269 (chip->npwm != 1) ? "s" : "");
1271 pwm_dbg_show(chip, s);
1276 static const struct seq_operations pwm_debugfs_sops = {
1277 .start = pwm_seq_start,
1278 .next = pwm_seq_next,
1279 .stop = pwm_seq_stop,
1280 .show = pwm_seq_show,
1283 DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1285 static int __init pwm_debugfs_init(void)
1287 debugfs_create_file("pwm", S_IFREG | 0444, NULL, NULL,
1292 subsys_initcall(pwm_debugfs_init);
1293 #endif /* CONFIG_DEBUG_FS */