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);
31 /* protects access to pwm_chips, allocated_pwms, and pwm_tree */
32 static DEFINE_MUTEX(pwm_lock);
34 static LIST_HEAD(pwm_chips);
35 static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
36 static RADIX_TREE(pwm_tree, GFP_KERNEL);
38 static struct pwm_device *pwm_to_device(unsigned int pwm)
40 return radix_tree_lookup(&pwm_tree, pwm);
43 /* Called with pwm_lock held */
44 static int alloc_pwms(unsigned int count)
48 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, 0,
51 if (start + count > MAX_PWMS)
54 bitmap_set(allocated_pwms, start, count);
59 /* Called with pwm_lock held */
60 static void free_pwms(struct pwm_chip *chip)
64 for (i = 0; i < chip->npwm; i++) {
65 struct pwm_device *pwm = &chip->pwms[i];
67 radix_tree_delete(&pwm_tree, pwm->pwm);
70 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
76 static struct pwm_chip *pwmchip_find_by_name(const char *name)
78 struct pwm_chip *chip;
83 mutex_lock(&pwm_lock);
85 list_for_each_entry(chip, &pwm_chips, list) {
86 const char *chip_name = dev_name(chip->dev);
88 if (chip_name && strcmp(chip_name, name) == 0) {
89 mutex_unlock(&pwm_lock);
94 mutex_unlock(&pwm_lock);
99 static int pwm_device_request(struct pwm_device *pwm, const char *label)
103 if (test_bit(PWMF_REQUESTED, &pwm->flags))
106 if (!try_module_get(pwm->chip->ops->owner))
109 if (pwm->chip->ops->request) {
110 err = pwm->chip->ops->request(pwm->chip, pwm);
112 module_put(pwm->chip->ops->owner);
117 if (pwm->chip->ops->get_state) {
119 * Zero-initialize state because most drivers are unaware of
120 * .usage_power. The other members of state are supposed to be
121 * set by lowlevel drivers. We still initialize the whole
122 * structure for simplicity even though this might paper over
123 * faulty implementations of .get_state().
125 struct pwm_state state = { 0, };
127 err = pwm->chip->ops->get_state(pwm->chip, pwm, &state);
128 trace_pwm_get(pwm, &state, err);
133 if (IS_ENABLED(CONFIG_PWM_DEBUG))
134 pwm->last = pwm->state;
137 set_bit(PWMF_REQUESTED, &pwm->flags);
144 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
146 struct pwm_device *pwm;
148 if (pc->of_pwm_n_cells < 2)
149 return ERR_PTR(-EINVAL);
151 /* flags in the third cell are optional */
152 if (args->args_count < 2)
153 return ERR_PTR(-EINVAL);
155 if (args->args[0] >= pc->npwm)
156 return ERR_PTR(-EINVAL);
158 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
162 pwm->args.period = args->args[1];
163 pwm->args.polarity = PWM_POLARITY_NORMAL;
165 if (pc->of_pwm_n_cells >= 3) {
166 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
167 pwm->args.polarity = PWM_POLARITY_INVERSED;
172 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
175 of_pwm_single_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
177 struct pwm_device *pwm;
179 if (pc->of_pwm_n_cells < 1)
180 return ERR_PTR(-EINVAL);
182 /* validate that one cell is specified, optionally with flags */
183 if (args->args_count != 1 && args->args_count != 2)
184 return ERR_PTR(-EINVAL);
186 pwm = pwm_request_from_chip(pc, 0, NULL);
190 pwm->args.period = args->args[0];
191 pwm->args.polarity = PWM_POLARITY_NORMAL;
193 if (args->args_count == 2 && args->args[2] & PWM_POLARITY_INVERTED)
194 pwm->args.polarity = PWM_POLARITY_INVERSED;
198 EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
200 static void of_pwmchip_add(struct pwm_chip *chip)
202 if (!chip->dev || !chip->dev->of_node)
205 if (!chip->of_xlate) {
208 if (of_property_read_u32(chip->dev->of_node, "#pwm-cells",
212 chip->of_xlate = of_pwm_xlate_with_flags;
213 chip->of_pwm_n_cells = pwm_cells;
216 of_node_get(chip->dev->of_node);
219 static void of_pwmchip_remove(struct pwm_chip *chip)
222 of_node_put(chip->dev->of_node);
226 * pwm_set_chip_data() - set private chip data for a PWM
228 * @data: pointer to chip-specific data
230 * Returns: 0 on success or a negative error code on failure.
232 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
237 pwm->chip_data = data;
241 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
244 * pwm_get_chip_data() - get private chip data for a PWM
247 * Returns: A pointer to the chip-private data for the PWM device.
249 void *pwm_get_chip_data(struct pwm_device *pwm)
251 return pwm ? pwm->chip_data : NULL;
253 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
255 static bool pwm_ops_check(const struct pwm_chip *chip)
257 const struct pwm_ops *ops = chip->ops;
262 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
264 "Please implement the .get_state() callback\n");
270 * pwmchip_add() - register a new PWM chip
271 * @chip: the PWM chip to add
273 * Register a new PWM chip.
275 * Returns: 0 on success or a negative error code on failure.
277 int pwmchip_add(struct pwm_chip *chip)
279 struct pwm_device *pwm;
283 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
286 if (!pwm_ops_check(chip))
289 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
293 mutex_lock(&pwm_lock);
295 ret = alloc_pwms(chip->npwm);
297 mutex_unlock(&pwm_lock);
304 for (i = 0; i < chip->npwm; i++) {
305 pwm = &chip->pwms[i];
308 pwm->pwm = chip->base + i;
311 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
314 list_add(&chip->list, &pwm_chips);
316 mutex_unlock(&pwm_lock);
318 if (IS_ENABLED(CONFIG_OF))
319 of_pwmchip_add(chip);
321 pwmchip_sysfs_export(chip);
325 EXPORT_SYMBOL_GPL(pwmchip_add);
328 * pwmchip_remove() - remove a PWM chip
329 * @chip: the PWM chip to remove
331 * Removes a PWM chip. This function may return busy if the PWM chip provides
332 * a PWM device that is still requested.
334 * Returns: 0 on success or a negative error code on failure.
336 void pwmchip_remove(struct pwm_chip *chip)
338 pwmchip_sysfs_unexport(chip);
340 mutex_lock(&pwm_lock);
342 list_del_init(&chip->list);
344 if (IS_ENABLED(CONFIG_OF))
345 of_pwmchip_remove(chip);
349 mutex_unlock(&pwm_lock);
351 EXPORT_SYMBOL_GPL(pwmchip_remove);
353 static void devm_pwmchip_remove(void *data)
355 struct pwm_chip *chip = data;
357 pwmchip_remove(chip);
360 int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip)
364 ret = pwmchip_add(chip);
368 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
370 EXPORT_SYMBOL_GPL(devm_pwmchip_add);
373 * pwm_request() - request a PWM device
374 * @pwm: global PWM device index
375 * @label: PWM device label
377 * This function is deprecated, use pwm_get() instead.
379 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
382 struct pwm_device *pwm_request(int pwm, const char *label)
384 struct pwm_device *dev;
387 if (pwm < 0 || pwm >= MAX_PWMS)
388 return ERR_PTR(-EINVAL);
390 mutex_lock(&pwm_lock);
392 dev = pwm_to_device(pwm);
394 dev = ERR_PTR(-EPROBE_DEFER);
398 err = pwm_device_request(dev, label);
403 mutex_unlock(&pwm_lock);
407 EXPORT_SYMBOL_GPL(pwm_request);
410 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
412 * @index: per-chip index of the PWM to request
413 * @label: a literal description string of this PWM
415 * Returns: A pointer to the PWM device at the given index of the given PWM
416 * chip. A negative error code is returned if the index is not valid for the
417 * specified PWM chip or if the PWM device cannot be requested.
419 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
423 struct pwm_device *pwm;
426 if (!chip || index >= chip->npwm)
427 return ERR_PTR(-EINVAL);
429 mutex_lock(&pwm_lock);
430 pwm = &chip->pwms[index];
432 err = pwm_device_request(pwm, label);
436 mutex_unlock(&pwm_lock);
439 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
442 * pwm_free() - free a PWM device
445 * This function is deprecated, use pwm_put() instead.
447 void pwm_free(struct pwm_device *pwm)
451 EXPORT_SYMBOL_GPL(pwm_free);
453 static void pwm_apply_state_debug(struct pwm_device *pwm,
454 const struct pwm_state *state)
456 struct pwm_state *last = &pwm->last;
457 struct pwm_chip *chip = pwm->chip;
458 struct pwm_state s1 = { 0 }, s2 = { 0 };
461 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
464 /* No reasonable diagnosis possible without .get_state() */
465 if (!chip->ops->get_state)
469 * *state was just applied. Read out the hardware state and do some
473 err = chip->ops->get_state(chip, pwm, &s1);
474 trace_pwm_get(pwm, &s1, err);
476 /* If that failed there isn't much to debug */
480 * The lowlevel driver either ignored .polarity (which is a bug) or as
481 * best effort inverted .polarity and fixed .duty_cycle respectively.
482 * Undo this inversion and fixup for further tests.
484 if (s1.enabled && s1.polarity != state->polarity) {
485 s2.polarity = state->polarity;
486 s2.duty_cycle = s1.period - s1.duty_cycle;
487 s2.period = s1.period;
488 s2.enabled = s1.enabled;
493 if (s2.polarity != state->polarity &&
494 state->duty_cycle < state->period)
495 dev_warn(chip->dev, ".apply ignored .polarity\n");
497 if (state->enabled &&
498 last->polarity == state->polarity &&
499 last->period > s2.period &&
500 last->period <= state->period)
502 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
503 state->period, s2.period, last->period);
505 if (state->enabled && state->period < s2.period)
507 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
508 state->period, s2.period);
510 if (state->enabled &&
511 last->polarity == state->polarity &&
512 last->period == s2.period &&
513 last->duty_cycle > s2.duty_cycle &&
514 last->duty_cycle <= state->duty_cycle)
516 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
517 state->duty_cycle, state->period,
518 s2.duty_cycle, s2.period,
519 last->duty_cycle, last->period);
521 if (state->enabled && state->duty_cycle < s2.duty_cycle)
523 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
524 state->duty_cycle, state->period,
525 s2.duty_cycle, s2.period);
527 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
529 "requested disabled, but yielded enabled with duty > 0\n");
531 /* reapply the state that the driver reported being configured. */
532 err = chip->ops->apply(chip, pwm, &s1);
533 trace_pwm_apply(pwm, &s1, err);
536 dev_err(chip->dev, "failed to reapply current setting\n");
540 *last = (struct pwm_state){ 0 };
541 err = chip->ops->get_state(chip, pwm, last);
542 trace_pwm_get(pwm, last, err);
546 /* reapplication of the current state should give an exact match */
547 if (s1.enabled != last->enabled ||
548 s1.polarity != last->polarity ||
549 (s1.enabled && s1.period != last->period) ||
550 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
552 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
553 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
554 last->enabled, last->polarity, last->duty_cycle,
560 * pwm_apply_state() - atomically apply a new state to a PWM device
562 * @state: new state to apply
564 int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
566 struct pwm_chip *chip;
570 * Some lowlevel driver's implementations of .apply() make use of
571 * mutexes, also with some drivers only returning when the new
572 * configuration is active calling pwm_apply_state() from atomic context
573 * is a bad idea. So make it explicit that calling this function might
578 if (!pwm || !state || !state->period ||
579 state->duty_cycle > state->period)
584 if (state->period == pwm->state.period &&
585 state->duty_cycle == pwm->state.duty_cycle &&
586 state->polarity == pwm->state.polarity &&
587 state->enabled == pwm->state.enabled &&
588 state->usage_power == pwm->state.usage_power)
591 err = chip->ops->apply(chip, pwm, state);
592 trace_pwm_apply(pwm, state, err);
599 * only do this after pwm->state was applied as some
600 * implementations of .get_state depend on this
602 pwm_apply_state_debug(pwm, state);
606 EXPORT_SYMBOL_GPL(pwm_apply_state);
609 * pwm_capture() - capture and report a PWM signal
611 * @result: structure to fill with capture result
612 * @timeout: time to wait, in milliseconds, before giving up on capture
614 * Returns: 0 on success or a negative error code on failure.
616 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
617 unsigned long timeout)
621 if (!pwm || !pwm->chip->ops)
624 if (!pwm->chip->ops->capture)
627 mutex_lock(&pwm_lock);
628 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
629 mutex_unlock(&pwm_lock);
633 EXPORT_SYMBOL_GPL(pwm_capture);
636 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
639 * This function will adjust the PWM config to the PWM arguments provided
640 * by the DT or PWM lookup table. This is particularly useful to adapt
641 * the bootloader config to the Linux one.
643 int pwm_adjust_config(struct pwm_device *pwm)
645 struct pwm_state state;
646 struct pwm_args pargs;
648 pwm_get_args(pwm, &pargs);
649 pwm_get_state(pwm, &state);
652 * If the current period is zero it means that either the PWM driver
653 * does not support initial state retrieval or the PWM has not yet
656 * In either case, we setup the new period and polarity, and assign a
660 state.duty_cycle = 0;
661 state.period = pargs.period;
662 state.polarity = pargs.polarity;
664 return pwm_apply_state(pwm, &state);
668 * Adjust the PWM duty cycle/period based on the period value provided
671 if (pargs.period != state.period) {
672 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
674 do_div(dutycycle, state.period);
675 state.duty_cycle = dutycycle;
676 state.period = pargs.period;
680 * If the polarity changed, we should also change the duty cycle.
682 if (pargs.polarity != state.polarity) {
683 state.polarity = pargs.polarity;
684 state.duty_cycle = state.period - state.duty_cycle;
687 return pwm_apply_state(pwm, &state);
689 EXPORT_SYMBOL_GPL(pwm_adjust_config);
691 static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
693 struct pwm_chip *chip;
695 mutex_lock(&pwm_lock);
697 list_for_each_entry(chip, &pwm_chips, list)
698 if (chip->dev && device_match_fwnode(chip->dev, fwnode)) {
699 mutex_unlock(&pwm_lock);
703 mutex_unlock(&pwm_lock);
705 return ERR_PTR(-EPROBE_DEFER);
708 static struct device_link *pwm_device_link_add(struct device *dev,
709 struct pwm_device *pwm)
711 struct device_link *dl;
715 * No device for the PWM consumer has been provided. It may
716 * impact the PM sequence ordering: the PWM supplier may get
717 * suspended before the consumer.
719 dev_warn(pwm->chip->dev,
720 "No consumer device specified to create a link to\n");
724 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
726 dev_err(dev, "failed to create device link to %s\n",
727 dev_name(pwm->chip->dev));
728 return ERR_PTR(-EINVAL);
735 * of_pwm_get() - request a PWM via the PWM framework
736 * @dev: device for PWM consumer
737 * @np: device node to get the PWM from
738 * @con_id: consumer name
740 * Returns the PWM device parsed from the phandle and index specified in the
741 * "pwms" property of a device tree node or a negative error-code on failure.
742 * Values parsed from the device tree are stored in the returned PWM device
745 * If con_id is NULL, the first PWM device listed in the "pwms" property will
746 * be requested. Otherwise the "pwm-names" property is used to do a reverse
747 * lookup of the PWM index. This also means that the "pwm-names" property
748 * becomes mandatory for devices that look up the PWM device via the con_id
751 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
752 * error code on failure.
754 static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
757 struct pwm_device *pwm = NULL;
758 struct of_phandle_args args;
759 struct device_link *dl;
765 index = of_property_match_string(np, "pwm-names", con_id);
767 return ERR_PTR(index);
770 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
773 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
777 pc = fwnode_to_pwmchip(of_fwnode_handle(args.np));
779 if (PTR_ERR(pc) != -EPROBE_DEFER)
780 pr_err("%s(): PWM chip not found\n", __func__);
786 pwm = pc->of_xlate(pc, &args);
790 dl = pwm_device_link_add(dev, pwm);
792 /* of_xlate ended up calling pwm_request_from_chip() */
799 * If a consumer name was not given, try to look it up from the
800 * "pwm-names" property if it exists. Otherwise use the name of
801 * the user device node.
804 err = of_property_read_string_index(np, "pwm-names", index,
813 of_node_put(args.np);
819 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
820 * @fwnode: firmware node to get the "pwms" property from
822 * Returns the PWM device parsed from the fwnode and index specified in the
823 * "pwms" property or a negative error-code on failure.
824 * Values parsed from the device tree are stored in the returned PWM device
827 * This is analogous to of_pwm_get() except con_id is not yet supported.
828 * ACPI entries must look like
829 * Package () {"pwms", Package ()
830 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
832 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
833 * error code on failure.
835 static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
837 struct pwm_device *pwm;
838 struct fwnode_reference_args args;
839 struct pwm_chip *chip;
842 memset(&args, 0, sizeof(args));
844 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
849 return ERR_PTR(-EPROTO);
851 chip = fwnode_to_pwmchip(args.fwnode);
853 return ERR_CAST(chip);
855 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
859 pwm->args.period = args.args[1];
860 pwm->args.polarity = PWM_POLARITY_NORMAL;
862 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
863 pwm->args.polarity = PWM_POLARITY_INVERSED;
869 * pwm_add_table() - register PWM device consumers
870 * @table: array of consumers to register
871 * @num: number of consumers in table
873 void pwm_add_table(struct pwm_lookup *table, size_t num)
875 mutex_lock(&pwm_lookup_lock);
878 list_add_tail(&table->list, &pwm_lookup_list);
882 mutex_unlock(&pwm_lookup_lock);
886 * pwm_remove_table() - unregister PWM device consumers
887 * @table: array of consumers to unregister
888 * @num: number of consumers in table
890 void pwm_remove_table(struct pwm_lookup *table, size_t num)
892 mutex_lock(&pwm_lookup_lock);
895 list_del(&table->list);
899 mutex_unlock(&pwm_lookup_lock);
903 * pwm_get() - look up and request a PWM device
904 * @dev: device for PWM consumer
905 * @con_id: consumer name
907 * Lookup is first attempted using DT. If the device was not instantiated from
908 * a device tree, a PWM chip and a relative index is looked up via a table
909 * supplied by board setup code (see pwm_add_table()).
911 * Once a PWM chip has been found the specified PWM device will be requested
912 * and is ready to be used.
914 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
915 * error code on failure.
917 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
919 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
920 const char *dev_id = dev ? dev_name(dev) : NULL;
921 struct pwm_device *pwm;
922 struct pwm_chip *chip;
923 struct device_link *dl;
924 unsigned int best = 0;
925 struct pwm_lookup *p, *chosen = NULL;
929 /* look up via DT first */
930 if (is_of_node(fwnode))
931 return of_pwm_get(dev, to_of_node(fwnode), con_id);
933 /* then lookup via ACPI */
934 if (is_acpi_node(fwnode)) {
935 pwm = acpi_pwm_get(fwnode);
936 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
941 * We look up the provider in the static table typically provided by
942 * board setup code. We first try to lookup the consumer device by
943 * name. If the consumer device was passed in as NULL or if no match
944 * was found, we try to find the consumer by directly looking it up
947 * If a match is found, the provider PWM chip is looked up by name
948 * and a PWM device is requested using the PWM device per-chip index.
950 * The lookup algorithm was shamelessly taken from the clock
953 * We do slightly fuzzy matching here:
954 * An entry with a NULL ID is assumed to be a wildcard.
955 * If an entry has a device ID, it must match
956 * If an entry has a connection ID, it must match
957 * Then we take the most specific entry - with the following order
958 * of precedence: dev+con > dev only > con only.
960 mutex_lock(&pwm_lookup_lock);
962 list_for_each_entry(p, &pwm_lookup_list, list) {
966 if (!dev_id || strcmp(p->dev_id, dev_id))
973 if (!con_id || strcmp(p->con_id, con_id))
989 mutex_unlock(&pwm_lookup_lock);
992 return ERR_PTR(-ENODEV);
994 chip = pwmchip_find_by_name(chosen->provider);
997 * If the lookup entry specifies a module, load the module and retry
998 * the PWM chip lookup. This can be used to work around driver load
999 * ordering issues if driver's can't be made to properly support the
1000 * deferred probe mechanism.
1002 if (!chip && chosen->module) {
1003 err = request_module(chosen->module);
1005 chip = pwmchip_find_by_name(chosen->provider);
1009 return ERR_PTR(-EPROBE_DEFER);
1011 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1015 dl = pwm_device_link_add(dev, pwm);
1018 return ERR_CAST(dl);
1021 pwm->args.period = chosen->period;
1022 pwm->args.polarity = chosen->polarity;
1026 EXPORT_SYMBOL_GPL(pwm_get);
1029 * pwm_put() - release a PWM device
1032 void pwm_put(struct pwm_device *pwm)
1037 mutex_lock(&pwm_lock);
1039 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1040 pr_warn("PWM device already freed\n");
1044 if (pwm->chip->ops->free)
1045 pwm->chip->ops->free(pwm->chip, pwm);
1047 pwm_set_chip_data(pwm, NULL);
1050 module_put(pwm->chip->ops->owner);
1052 mutex_unlock(&pwm_lock);
1054 EXPORT_SYMBOL_GPL(pwm_put);
1056 static void devm_pwm_release(void *pwm)
1062 * devm_pwm_get() - resource managed pwm_get()
1063 * @dev: device for PWM consumer
1064 * @con_id: consumer name
1066 * This function performs like pwm_get() but the acquired PWM device will
1067 * automatically be released on driver detach.
1069 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1070 * error code on failure.
1072 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1074 struct pwm_device *pwm;
1077 pwm = pwm_get(dev, con_id);
1081 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1083 return ERR_PTR(ret);
1087 EXPORT_SYMBOL_GPL(devm_pwm_get);
1090 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1091 * @dev: device for PWM consumer
1092 * @fwnode: firmware node to get the PWM from
1093 * @con_id: consumer name
1095 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1096 * acpi_pwm_get() for a detailed description.
1098 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1099 * error code on failure.
1101 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1102 struct fwnode_handle *fwnode,
1105 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1108 if (is_of_node(fwnode))
1109 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1110 else if (is_acpi_node(fwnode))
1111 pwm = acpi_pwm_get(fwnode);
1115 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1117 return ERR_PTR(ret);
1121 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1123 #ifdef CONFIG_DEBUG_FS
1124 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1128 for (i = 0; i < chip->npwm; i++) {
1129 struct pwm_device *pwm = &chip->pwms[i];
1130 struct pwm_state state;
1132 pwm_get_state(pwm, &state);
1134 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1136 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1137 seq_puts(s, " requested");
1140 seq_puts(s, " enabled");
1142 seq_printf(s, " period: %llu ns", state.period);
1143 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1144 seq_printf(s, " polarity: %s",
1145 state.polarity ? "inverse" : "normal");
1147 if (state.usage_power)
1148 seq_puts(s, " usage_power");
1154 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1156 mutex_lock(&pwm_lock);
1159 return seq_list_start(&pwm_chips, *pos);
1162 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1166 return seq_list_next(v, &pwm_chips, pos);
1169 static void pwm_seq_stop(struct seq_file *s, void *v)
1171 mutex_unlock(&pwm_lock);
1174 static int pwm_seq_show(struct seq_file *s, void *v)
1176 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1178 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1179 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1180 dev_name(chip->dev), chip->npwm,
1181 (chip->npwm != 1) ? "s" : "");
1183 pwm_dbg_show(chip, s);
1188 static const struct seq_operations pwm_debugfs_sops = {
1189 .start = pwm_seq_start,
1190 .next = pwm_seq_next,
1191 .stop = pwm_seq_stop,
1192 .show = pwm_seq_show,
1195 DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1197 static int __init pwm_debugfs_init(void)
1199 debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1203 subsys_initcall(pwm_debugfs_init);
1204 #endif /* CONFIG_DEBUG_FS */