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 /* protects access to pwm_chips */
28 static DEFINE_MUTEX(pwm_lock);
30 static DEFINE_IDR(pwm_chips);
32 static void pwm_apply_debug(struct pwm_device *pwm,
33 const struct pwm_state *state)
35 struct pwm_state *last = &pwm->last;
36 struct pwm_chip *chip = pwm->chip;
37 struct pwm_state s1 = { 0 }, s2 = { 0 };
40 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
43 /* No reasonable diagnosis possible without .get_state() */
44 if (!chip->ops->get_state)
48 * *state was just applied. Read out the hardware state and do some
52 err = chip->ops->get_state(chip, pwm, &s1);
53 trace_pwm_get(pwm, &s1, err);
55 /* If that failed there isn't much to debug */
59 * The lowlevel driver either ignored .polarity (which is a bug) or as
60 * best effort inverted .polarity and fixed .duty_cycle respectively.
61 * Undo this inversion and fixup for further tests.
63 if (s1.enabled && s1.polarity != state->polarity) {
64 s2.polarity = state->polarity;
65 s2.duty_cycle = s1.period - s1.duty_cycle;
66 s2.period = s1.period;
67 s2.enabled = s1.enabled;
72 if (s2.polarity != state->polarity &&
73 state->duty_cycle < state->period)
74 dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n");
77 last->polarity == state->polarity &&
78 last->period > s2.period &&
79 last->period <= state->period)
80 dev_warn(pwmchip_parent(chip),
81 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
82 state->period, s2.period, last->period);
84 if (state->enabled && state->period < s2.period)
85 dev_warn(pwmchip_parent(chip),
86 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
87 state->period, s2.period);
90 last->polarity == state->polarity &&
91 last->period == s2.period &&
92 last->duty_cycle > s2.duty_cycle &&
93 last->duty_cycle <= state->duty_cycle)
94 dev_warn(pwmchip_parent(chip),
95 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
96 state->duty_cycle, state->period,
97 s2.duty_cycle, s2.period,
98 last->duty_cycle, last->period);
100 if (state->enabled && state->duty_cycle < s2.duty_cycle)
101 dev_warn(pwmchip_parent(chip),
102 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
103 state->duty_cycle, state->period,
104 s2.duty_cycle, s2.period);
106 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
107 dev_warn(pwmchip_parent(chip),
108 "requested disabled, but yielded enabled with duty > 0\n");
110 /* reapply the state that the driver reported being configured. */
111 err = chip->ops->apply(chip, pwm, &s1);
112 trace_pwm_apply(pwm, &s1, err);
115 dev_err(pwmchip_parent(chip), "failed to reapply current setting\n");
119 *last = (struct pwm_state){ 0 };
120 err = chip->ops->get_state(chip, pwm, last);
121 trace_pwm_get(pwm, last, err);
125 /* reapplication of the current state should give an exact match */
126 if (s1.enabled != last->enabled ||
127 s1.polarity != last->polarity ||
128 (s1.enabled && s1.period != last->period) ||
129 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
130 dev_err(pwmchip_parent(chip),
131 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
132 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
133 last->enabled, last->polarity, last->duty_cycle,
139 * __pwm_apply() - atomically apply a new state to a PWM device
141 * @state: new state to apply
143 static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
145 struct pwm_chip *chip;
148 if (!pwm || !state || !state->period ||
149 state->duty_cycle > state->period)
154 if (state->period == pwm->state.period &&
155 state->duty_cycle == pwm->state.duty_cycle &&
156 state->polarity == pwm->state.polarity &&
157 state->enabled == pwm->state.enabled &&
158 state->usage_power == pwm->state.usage_power)
161 err = chip->ops->apply(chip, pwm, state);
162 trace_pwm_apply(pwm, state, err);
169 * only do this after pwm->state was applied as some
170 * implementations of .get_state depend on this
172 pwm_apply_debug(pwm, state);
178 * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
179 * Cannot be used in atomic context.
181 * @state: new state to apply
183 int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
188 * Some lowlevel driver's implementations of .apply() make use of
189 * mutexes, also with some drivers only returning when the new
190 * configuration is active calling pwm_apply_might_sleep() from atomic context
191 * is a bad idea. So make it explicit that calling this function might
196 if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
198 * Catch any drivers that have been marked as atomic but
199 * that will sleep anyway.
202 err = __pwm_apply(pwm, state);
205 err = __pwm_apply(pwm, state);
210 EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);
213 * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
214 * Not all PWM devices support this function, check with pwm_might_sleep().
216 * @state: new state to apply
218 int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
220 WARN_ONCE(!pwm->chip->atomic,
221 "sleeping PWM driver used in atomic context\n");
223 return __pwm_apply(pwm, state);
225 EXPORT_SYMBOL_GPL(pwm_apply_atomic);
228 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
231 * This function will adjust the PWM config to the PWM arguments provided
232 * by the DT or PWM lookup table. This is particularly useful to adapt
233 * the bootloader config to the Linux one.
235 int pwm_adjust_config(struct pwm_device *pwm)
237 struct pwm_state state;
238 struct pwm_args pargs;
240 pwm_get_args(pwm, &pargs);
241 pwm_get_state(pwm, &state);
244 * If the current period is zero it means that either the PWM driver
245 * does not support initial state retrieval or the PWM has not yet
248 * In either case, we setup the new period and polarity, and assign a
252 state.duty_cycle = 0;
253 state.period = pargs.period;
254 state.polarity = pargs.polarity;
256 return pwm_apply_might_sleep(pwm, &state);
260 * Adjust the PWM duty cycle/period based on the period value provided
263 if (pargs.period != state.period) {
264 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
266 do_div(dutycycle, state.period);
267 state.duty_cycle = dutycycle;
268 state.period = pargs.period;
272 * If the polarity changed, we should also change the duty cycle.
274 if (pargs.polarity != state.polarity) {
275 state.polarity = pargs.polarity;
276 state.duty_cycle = state.period - state.duty_cycle;
279 return pwm_apply_might_sleep(pwm, &state);
281 EXPORT_SYMBOL_GPL(pwm_adjust_config);
284 * pwm_capture() - capture and report a PWM signal
286 * @result: structure to fill with capture result
287 * @timeout: time to wait, in milliseconds, before giving up on capture
289 * Returns: 0 on success or a negative error code on failure.
291 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
292 unsigned long timeout)
296 if (!pwm || !pwm->chip->ops)
299 if (!pwm->chip->ops->capture)
302 mutex_lock(&pwm_lock);
303 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
304 mutex_unlock(&pwm_lock);
308 EXPORT_SYMBOL_GPL(pwm_capture);
310 static struct pwm_chip *pwmchip_find_by_name(const char *name)
312 struct pwm_chip *chip;
313 unsigned long id, tmp;
318 mutex_lock(&pwm_lock);
320 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
321 const char *chip_name = dev_name(pwmchip_parent(chip));
323 if (chip_name && strcmp(chip_name, name) == 0) {
324 mutex_unlock(&pwm_lock);
329 mutex_unlock(&pwm_lock);
334 static int pwm_device_request(struct pwm_device *pwm, const char *label)
337 struct pwm_chip *chip = pwm->chip;
338 const struct pwm_ops *ops = chip->ops;
340 if (test_bit(PWMF_REQUESTED, &pwm->flags))
343 if (!try_module_get(chip->owner))
347 err = ops->request(chip, pwm);
349 module_put(chip->owner);
354 if (ops->get_state) {
356 * Zero-initialize state because most drivers are unaware of
357 * .usage_power. The other members of state are supposed to be
358 * set by lowlevel drivers. We still initialize the whole
359 * structure for simplicity even though this might paper over
360 * faulty implementations of .get_state().
362 struct pwm_state state = { 0, };
364 err = ops->get_state(chip, pwm, &state);
365 trace_pwm_get(pwm, &state, err);
370 if (IS_ENABLED(CONFIG_PWM_DEBUG))
371 pwm->last = pwm->state;
374 set_bit(PWMF_REQUESTED, &pwm->flags);
381 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
383 * @index: per-chip index of the PWM to request
384 * @label: a literal description string of this PWM
386 * Returns: A pointer to the PWM device at the given index of the given PWM
387 * chip. A negative error code is returned if the index is not valid for the
388 * specified PWM chip or if the PWM device cannot be requested.
390 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
394 struct pwm_device *pwm;
397 if (!chip || index >= chip->npwm)
398 return ERR_PTR(-EINVAL);
400 mutex_lock(&pwm_lock);
401 pwm = &chip->pwms[index];
403 err = pwm_device_request(pwm, label);
407 mutex_unlock(&pwm_lock);
410 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
414 of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
416 struct pwm_device *pwm;
418 /* period in the second cell and flags in the third cell are optional */
419 if (args->args_count < 1)
420 return ERR_PTR(-EINVAL);
422 pwm = pwm_request_from_chip(chip, args->args[0], NULL);
426 if (args->args_count > 1)
427 pwm->args.period = args->args[1];
429 pwm->args.polarity = PWM_POLARITY_NORMAL;
430 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
431 pwm->args.polarity = PWM_POLARITY_INVERSED;
435 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
438 of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
440 struct pwm_device *pwm;
442 pwm = pwm_request_from_chip(chip, 0, NULL);
446 if (args->args_count > 0)
447 pwm->args.period = args->args[0];
449 pwm->args.polarity = PWM_POLARITY_NORMAL;
450 if (args->args_count > 1 && args->args[1] & PWM_POLARITY_INVERTED)
451 pwm->args.polarity = PWM_POLARITY_INVERSED;
455 EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
457 #define PWMCHIP_ALIGN ARCH_DMA_MINALIGN
459 static void *pwmchip_priv(struct pwm_chip *chip)
461 return (void *)chip + ALIGN(sizeof(*chip), PWMCHIP_ALIGN);
464 /* This is the counterpart to pwmchip_alloc() */
465 void pwmchip_put(struct pwm_chip *chip)
469 EXPORT_SYMBOL_GPL(pwmchip_put);
471 struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
473 struct pwm_chip *chip;
476 alloc_size = size_add(ALIGN(sizeof(*chip), PWMCHIP_ALIGN), sizeof_priv);
478 chip = kzalloc(alloc_size, GFP_KERNEL);
480 return ERR_PTR(-ENOMEM);
485 pwmchip_set_drvdata(chip, pwmchip_priv(chip));
489 EXPORT_SYMBOL_GPL(pwmchip_alloc);
491 static void devm_pwmchip_put(void *data)
493 struct pwm_chip *chip = data;
498 struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
500 struct pwm_chip *chip;
503 chip = pwmchip_alloc(parent, npwm, sizeof_priv);
507 ret = devm_add_action_or_reset(parent, devm_pwmchip_put, chip);
513 EXPORT_SYMBOL_GPL(devm_pwmchip_alloc);
515 static void of_pwmchip_add(struct pwm_chip *chip)
517 if (!pwmchip_parent(chip) || !pwmchip_parent(chip)->of_node)
521 chip->of_xlate = of_pwm_xlate_with_flags;
523 of_node_get(pwmchip_parent(chip)->of_node);
526 static void of_pwmchip_remove(struct pwm_chip *chip)
528 if (pwmchip_parent(chip))
529 of_node_put(pwmchip_parent(chip)->of_node);
532 static bool pwm_ops_check(const struct pwm_chip *chip)
534 const struct pwm_ops *ops = chip->ops;
539 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
540 dev_warn(pwmchip_parent(chip),
541 "Please implement the .get_state() callback\n");
547 * __pwmchip_add() - register a new PWM chip
548 * @chip: the PWM chip to add
549 * @owner: reference to the module providing the chip.
551 * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
552 * pwmchip_add wrapper to do this right.
554 * Returns: 0 on success or a negative error code on failure.
556 int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
561 if (!chip || !pwmchip_parent(chip) || !chip->ops || !chip->npwm)
564 if (!pwm_ops_check(chip))
569 chip->pwms = kcalloc(chip->npwm, sizeof(*chip->pwms), GFP_KERNEL);
573 mutex_lock(&pwm_lock);
575 ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
577 mutex_unlock(&pwm_lock);
584 for (i = 0; i < chip->npwm; i++) {
585 struct pwm_device *pwm = &chip->pwms[i];
591 mutex_unlock(&pwm_lock);
593 if (IS_ENABLED(CONFIG_OF))
594 of_pwmchip_add(chip);
596 pwmchip_sysfs_export(chip);
600 EXPORT_SYMBOL_GPL(__pwmchip_add);
603 * pwmchip_remove() - remove a PWM chip
604 * @chip: the PWM chip to remove
606 * Removes a PWM chip.
608 void pwmchip_remove(struct pwm_chip *chip)
610 pwmchip_sysfs_unexport(chip);
612 if (IS_ENABLED(CONFIG_OF))
613 of_pwmchip_remove(chip);
615 mutex_lock(&pwm_lock);
617 idr_remove(&pwm_chips, chip->id);
619 mutex_unlock(&pwm_lock);
623 EXPORT_SYMBOL_GPL(pwmchip_remove);
625 static void devm_pwmchip_remove(void *data)
627 struct pwm_chip *chip = data;
629 pwmchip_remove(chip);
632 int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
636 ret = __pwmchip_add(chip, owner);
640 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
642 EXPORT_SYMBOL_GPL(__devm_pwmchip_add);
644 static struct device_link *pwm_device_link_add(struct device *dev,
645 struct pwm_device *pwm)
647 struct device_link *dl;
651 * No device for the PWM consumer has been provided. It may
652 * impact the PM sequence ordering: the PWM supplier may get
653 * suspended before the consumer.
655 dev_warn(pwmchip_parent(pwm->chip),
656 "No consumer device specified to create a link to\n");
660 dl = device_link_add(dev, pwmchip_parent(pwm->chip), DL_FLAG_AUTOREMOVE_CONSUMER);
662 dev_err(dev, "failed to create device link to %s\n",
663 dev_name(pwmchip_parent(pwm->chip)));
664 return ERR_PTR(-EINVAL);
670 static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
672 struct pwm_chip *chip;
673 unsigned long id, tmp;
675 mutex_lock(&pwm_lock);
677 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
678 if (pwmchip_parent(chip) && device_match_fwnode(pwmchip_parent(chip), fwnode)) {
679 mutex_unlock(&pwm_lock);
683 mutex_unlock(&pwm_lock);
685 return ERR_PTR(-EPROBE_DEFER);
689 * of_pwm_get() - request a PWM via the PWM framework
690 * @dev: device for PWM consumer
691 * @np: device node to get the PWM from
692 * @con_id: consumer name
694 * Returns the PWM device parsed from the phandle and index specified in the
695 * "pwms" property of a device tree node or a negative error-code on failure.
696 * Values parsed from the device tree are stored in the returned PWM device
699 * If con_id is NULL, the first PWM device listed in the "pwms" property will
700 * be requested. Otherwise the "pwm-names" property is used to do a reverse
701 * lookup of the PWM index. This also means that the "pwm-names" property
702 * becomes mandatory for devices that look up the PWM device via the con_id
705 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
706 * error code on failure.
708 static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
711 struct pwm_device *pwm = NULL;
712 struct of_phandle_args args;
713 struct device_link *dl;
714 struct pwm_chip *chip;
719 index = of_property_match_string(np, "pwm-names", con_id);
721 return ERR_PTR(index);
724 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
727 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
731 chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
733 if (PTR_ERR(chip) != -EPROBE_DEFER)
734 pr_err("%s(): PWM chip not found\n", __func__);
736 pwm = ERR_CAST(chip);
740 pwm = chip->of_xlate(chip, &args);
744 dl = pwm_device_link_add(dev, pwm);
746 /* of_xlate ended up calling pwm_request_from_chip() */
753 * If a consumer name was not given, try to look it up from the
754 * "pwm-names" property if it exists. Otherwise use the name of
755 * the user device node.
758 err = of_property_read_string_index(np, "pwm-names", index,
767 of_node_put(args.np);
773 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
774 * @fwnode: firmware node to get the "pwms" property from
776 * Returns the PWM device parsed from the fwnode and index specified in the
777 * "pwms" property or a negative error-code on failure.
778 * Values parsed from the device tree are stored in the returned PWM device
781 * This is analogous to of_pwm_get() except con_id is not yet supported.
782 * ACPI entries must look like
783 * Package () {"pwms", Package ()
784 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
786 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
787 * error code on failure.
789 static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
791 struct pwm_device *pwm;
792 struct fwnode_reference_args args;
793 struct pwm_chip *chip;
796 memset(&args, 0, sizeof(args));
798 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
803 return ERR_PTR(-EPROTO);
805 chip = fwnode_to_pwmchip(args.fwnode);
807 return ERR_CAST(chip);
809 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
813 pwm->args.period = args.args[1];
814 pwm->args.polarity = PWM_POLARITY_NORMAL;
816 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
817 pwm->args.polarity = PWM_POLARITY_INVERSED;
822 static DEFINE_MUTEX(pwm_lookup_lock);
823 static LIST_HEAD(pwm_lookup_list);
826 * pwm_add_table() - register PWM device consumers
827 * @table: array of consumers to register
828 * @num: number of consumers in table
830 void pwm_add_table(struct pwm_lookup *table, size_t num)
832 mutex_lock(&pwm_lookup_lock);
835 list_add_tail(&table->list, &pwm_lookup_list);
839 mutex_unlock(&pwm_lookup_lock);
843 * pwm_remove_table() - unregister PWM device consumers
844 * @table: array of consumers to unregister
845 * @num: number of consumers in table
847 void pwm_remove_table(struct pwm_lookup *table, size_t num)
849 mutex_lock(&pwm_lookup_lock);
852 list_del(&table->list);
856 mutex_unlock(&pwm_lookup_lock);
860 * pwm_get() - look up and request a PWM device
861 * @dev: device for PWM consumer
862 * @con_id: consumer name
864 * Lookup is first attempted using DT. If the device was not instantiated from
865 * a device tree, a PWM chip and a relative index is looked up via a table
866 * supplied by board setup code (see pwm_add_table()).
868 * Once a PWM chip has been found the specified PWM device will be requested
869 * and is ready to be used.
871 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
872 * error code on failure.
874 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
876 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
877 const char *dev_id = dev ? dev_name(dev) : NULL;
878 struct pwm_device *pwm;
879 struct pwm_chip *chip;
880 struct device_link *dl;
881 unsigned int best = 0;
882 struct pwm_lookup *p, *chosen = NULL;
886 /* look up via DT first */
887 if (is_of_node(fwnode))
888 return of_pwm_get(dev, to_of_node(fwnode), con_id);
890 /* then lookup via ACPI */
891 if (is_acpi_node(fwnode)) {
892 pwm = acpi_pwm_get(fwnode);
893 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
898 * We look up the provider in the static table typically provided by
899 * board setup code. We first try to lookup the consumer device by
900 * name. If the consumer device was passed in as NULL or if no match
901 * was found, we try to find the consumer by directly looking it up
904 * If a match is found, the provider PWM chip is looked up by name
905 * and a PWM device is requested using the PWM device per-chip index.
907 * The lookup algorithm was shamelessly taken from the clock
910 * We do slightly fuzzy matching here:
911 * An entry with a NULL ID is assumed to be a wildcard.
912 * If an entry has a device ID, it must match
913 * If an entry has a connection ID, it must match
914 * Then we take the most specific entry - with the following order
915 * of precedence: dev+con > dev only > con only.
917 mutex_lock(&pwm_lookup_lock);
919 list_for_each_entry(p, &pwm_lookup_list, list) {
923 if (!dev_id || strcmp(p->dev_id, dev_id))
930 if (!con_id || strcmp(p->con_id, con_id))
946 mutex_unlock(&pwm_lookup_lock);
949 return ERR_PTR(-ENODEV);
951 chip = pwmchip_find_by_name(chosen->provider);
954 * If the lookup entry specifies a module, load the module and retry
955 * the PWM chip lookup. This can be used to work around driver load
956 * ordering issues if driver's can't be made to properly support the
957 * deferred probe mechanism.
959 if (!chip && chosen->module) {
960 err = request_module(chosen->module);
962 chip = pwmchip_find_by_name(chosen->provider);
966 return ERR_PTR(-EPROBE_DEFER);
968 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
972 dl = pwm_device_link_add(dev, pwm);
978 pwm->args.period = chosen->period;
979 pwm->args.polarity = chosen->polarity;
983 EXPORT_SYMBOL_GPL(pwm_get);
986 * pwm_put() - release a PWM device
989 void pwm_put(struct pwm_device *pwm)
994 mutex_lock(&pwm_lock);
996 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
997 pr_warn("PWM device already freed\n");
1001 if (pwm->chip->ops->free)
1002 pwm->chip->ops->free(pwm->chip, pwm);
1006 module_put(pwm->chip->owner);
1008 mutex_unlock(&pwm_lock);
1010 EXPORT_SYMBOL_GPL(pwm_put);
1012 static void devm_pwm_release(void *pwm)
1018 * devm_pwm_get() - resource managed pwm_get()
1019 * @dev: device for PWM consumer
1020 * @con_id: consumer name
1022 * This function performs like pwm_get() but the acquired PWM device will
1023 * automatically be released on driver detach.
1025 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1026 * error code on failure.
1028 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1030 struct pwm_device *pwm;
1033 pwm = pwm_get(dev, con_id);
1037 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1039 return ERR_PTR(ret);
1043 EXPORT_SYMBOL_GPL(devm_pwm_get);
1046 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1047 * @dev: device for PWM consumer
1048 * @fwnode: firmware node to get the PWM from
1049 * @con_id: consumer name
1051 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1052 * acpi_pwm_get() for a detailed description.
1054 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1055 * error code on failure.
1057 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1058 struct fwnode_handle *fwnode,
1061 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1064 if (is_of_node(fwnode))
1065 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1066 else if (is_acpi_node(fwnode))
1067 pwm = acpi_pwm_get(fwnode);
1071 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1073 return ERR_PTR(ret);
1077 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1079 #ifdef CONFIG_DEBUG_FS
1080 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1084 for (i = 0; i < chip->npwm; i++) {
1085 struct pwm_device *pwm = &chip->pwms[i];
1086 struct pwm_state state;
1088 pwm_get_state(pwm, &state);
1090 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1092 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1093 seq_puts(s, " requested");
1096 seq_puts(s, " enabled");
1098 seq_printf(s, " period: %llu ns", state.period);
1099 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1100 seq_printf(s, " polarity: %s",
1101 state.polarity ? "inverse" : "normal");
1103 if (state.usage_power)
1104 seq_puts(s, " usage_power");
1110 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1112 unsigned long id = *pos;
1115 mutex_lock(&pwm_lock);
1118 ret = idr_get_next_ul(&pwm_chips, &id);
1123 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1125 unsigned long id = *pos + 1;
1130 ret = idr_get_next_ul(&pwm_chips, &id);
1135 static void pwm_seq_stop(struct seq_file *s, void *v)
1137 mutex_unlock(&pwm_lock);
1140 static int pwm_seq_show(struct seq_file *s, void *v)
1142 struct pwm_chip *chip = v;
1144 seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n",
1145 (char *)s->private, chip->id,
1146 pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus",
1147 dev_name(pwmchip_parent(chip)), chip->npwm,
1148 (chip->npwm != 1) ? "s" : "");
1150 pwm_dbg_show(chip, s);
1155 static const struct seq_operations pwm_debugfs_sops = {
1156 .start = pwm_seq_start,
1157 .next = pwm_seq_next,
1158 .stop = pwm_seq_stop,
1159 .show = pwm_seq_show,
1162 DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1164 static int __init pwm_debugfs_init(void)
1166 debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1170 subsys_initcall(pwm_debugfs_init);
1171 #endif /* CONFIG_DEBUG_FS */