2 * Generic pwmlib implementation
4 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
5 * Copyright (C) 2011-2012 Avionic Design GmbH
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2, or (at your option)
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; see the file COPYING. If not, write to
19 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <linux/module.h>
23 #include <linux/pwm.h>
24 #include <linux/radix-tree.h>
25 #include <linux/list.h>
26 #include <linux/mutex.h>
27 #include <linux/err.h>
28 #include <linux/slab.h>
29 #include <linux/device.h>
30 #include <linux/debugfs.h>
31 #include <linux/seq_file.h>
33 #include <dt-bindings/pwm/pwm.h>
37 static DEFINE_MUTEX(pwm_lookup_lock);
38 static LIST_HEAD(pwm_lookup_list);
39 static DEFINE_MUTEX(pwm_lock);
40 static LIST_HEAD(pwm_chips);
41 static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
42 static RADIX_TREE(pwm_tree, GFP_KERNEL);
44 static struct pwm_device *pwm_to_device(unsigned int pwm)
46 return radix_tree_lookup(&pwm_tree, pwm);
49 static int alloc_pwms(int pwm, unsigned int count)
51 unsigned int from = 0;
60 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
63 if (pwm >= 0 && start != pwm)
66 if (start + count > MAX_PWMS)
72 static void free_pwms(struct pwm_chip *chip)
76 for (i = 0; i < chip->npwm; i++) {
77 struct pwm_device *pwm = &chip->pwms[i];
79 radix_tree_delete(&pwm_tree, pwm->pwm);
82 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
88 static struct pwm_chip *pwmchip_find_by_name(const char *name)
90 struct pwm_chip *chip;
95 mutex_lock(&pwm_lock);
97 list_for_each_entry(chip, &pwm_chips, list) {
98 const char *chip_name = dev_name(chip->dev);
100 if (chip_name && strcmp(chip_name, name) == 0) {
101 mutex_unlock(&pwm_lock);
106 mutex_unlock(&pwm_lock);
111 static int pwm_device_request(struct pwm_device *pwm, const char *label)
115 if (test_bit(PWMF_REQUESTED, &pwm->flags))
118 if (!try_module_get(pwm->chip->ops->owner))
121 if (pwm->chip->ops->request) {
122 err = pwm->chip->ops->request(pwm->chip, pwm);
124 module_put(pwm->chip->ops->owner);
129 set_bit(PWMF_REQUESTED, &pwm->flags);
136 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
138 struct pwm_device *pwm;
140 if (pc->of_pwm_n_cells < 3)
141 return ERR_PTR(-EINVAL);
143 if (args->args[0] >= pc->npwm)
144 return ERR_PTR(-EINVAL);
146 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
150 pwm->args.period = args->args[1];
152 if (args->args[2] & PWM_POLARITY_INVERTED)
153 pwm->args.polarity = PWM_POLARITY_INVERSED;
155 pwm->args.polarity = PWM_POLARITY_NORMAL;
159 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
161 static struct pwm_device *
162 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
164 struct pwm_device *pwm;
166 if (pc->of_pwm_n_cells < 2)
167 return ERR_PTR(-EINVAL);
169 if (args->args[0] >= pc->npwm)
170 return ERR_PTR(-EINVAL);
172 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
176 pwm->args.period = args->args[1];
181 static void of_pwmchip_add(struct pwm_chip *chip)
183 if (!chip->dev || !chip->dev->of_node)
186 if (!chip->of_xlate) {
187 chip->of_xlate = of_pwm_simple_xlate;
188 chip->of_pwm_n_cells = 2;
191 of_node_get(chip->dev->of_node);
194 static void of_pwmchip_remove(struct pwm_chip *chip)
197 of_node_put(chip->dev->of_node);
201 * pwm_set_chip_data() - set private chip data for a PWM
203 * @data: pointer to chip-specific data
205 * Returns: 0 on success or a negative error code on failure.
207 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
212 pwm->chip_data = data;
216 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
219 * pwm_get_chip_data() - get private chip data for a PWM
222 * Returns: A pointer to the chip-private data for the PWM device.
224 void *pwm_get_chip_data(struct pwm_device *pwm)
226 return pwm ? pwm->chip_data : NULL;
228 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
230 static bool pwm_ops_check(const struct pwm_ops *ops)
232 /* driver supports legacy, non-atomic operation */
233 if (ops->config && ops->enable && ops->disable)
236 /* driver supports atomic operation */
244 * pwmchip_add_with_polarity() - register a new PWM chip
245 * @chip: the PWM chip to add
246 * @polarity: initial polarity of PWM channels
248 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
249 * will be used. The initial polarity for all channels is specified by the
250 * @polarity parameter.
252 * Returns: 0 on success or a negative error code on failure.
254 int pwmchip_add_with_polarity(struct pwm_chip *chip,
255 enum pwm_polarity polarity)
257 struct pwm_device *pwm;
261 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
264 if (!pwm_ops_check(chip->ops))
267 mutex_lock(&pwm_lock);
269 ret = alloc_pwms(chip->base, chip->npwm);
273 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
281 for (i = 0; i < chip->npwm; i++) {
282 pwm = &chip->pwms[i];
285 pwm->pwm = chip->base + i;
287 pwm->state.polarity = polarity;
289 if (chip->ops->get_state)
290 chip->ops->get_state(chip, pwm, &pwm->state);
292 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
295 bitmap_set(allocated_pwms, chip->base, chip->npwm);
297 INIT_LIST_HEAD(&chip->list);
298 list_add(&chip->list, &pwm_chips);
302 if (IS_ENABLED(CONFIG_OF))
303 of_pwmchip_add(chip);
305 pwmchip_sysfs_export(chip);
308 mutex_unlock(&pwm_lock);
311 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
314 * pwmchip_add() - register a new PWM chip
315 * @chip: the PWM chip to add
317 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
318 * will be used. The initial polarity for all channels is normal.
320 * Returns: 0 on success or a negative error code on failure.
322 int pwmchip_add(struct pwm_chip *chip)
324 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
326 EXPORT_SYMBOL_GPL(pwmchip_add);
329 * pwmchip_remove() - remove a PWM chip
330 * @chip: the PWM chip to remove
332 * Removes a PWM chip. This function may return busy if the PWM chip provides
333 * a PWM device that is still requested.
335 * Returns: 0 on success or a negative error code on failure.
337 int pwmchip_remove(struct pwm_chip *chip)
342 mutex_lock(&pwm_lock);
344 for (i = 0; i < chip->npwm; i++) {
345 struct pwm_device *pwm = &chip->pwms[i];
347 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
353 list_del_init(&chip->list);
355 if (IS_ENABLED(CONFIG_OF))
356 of_pwmchip_remove(chip);
360 pwmchip_sysfs_unexport(chip);
363 mutex_unlock(&pwm_lock);
366 EXPORT_SYMBOL_GPL(pwmchip_remove);
369 * pwm_request() - request a PWM device
370 * @pwm: global PWM device index
371 * @label: PWM device label
373 * This function is deprecated, use pwm_get() instead.
375 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
378 struct pwm_device *pwm_request(int pwm, const char *label)
380 struct pwm_device *dev;
383 if (pwm < 0 || pwm >= MAX_PWMS)
384 return ERR_PTR(-EINVAL);
386 mutex_lock(&pwm_lock);
388 dev = pwm_to_device(pwm);
390 dev = ERR_PTR(-EPROBE_DEFER);
394 err = pwm_device_request(dev, label);
399 mutex_unlock(&pwm_lock);
403 EXPORT_SYMBOL_GPL(pwm_request);
406 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
408 * @index: per-chip index of the PWM to request
409 * @label: a literal description string of this PWM
411 * Returns: A pointer to the PWM device at the given index of the given PWM
412 * chip. A negative error code is returned if the index is not valid for the
413 * specified PWM chip or if the PWM device cannot be requested.
415 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
419 struct pwm_device *pwm;
422 if (!chip || index >= chip->npwm)
423 return ERR_PTR(-EINVAL);
425 mutex_lock(&pwm_lock);
426 pwm = &chip->pwms[index];
428 err = pwm_device_request(pwm, label);
432 mutex_unlock(&pwm_lock);
435 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
438 * pwm_free() - free a PWM device
441 * This function is deprecated, use pwm_put() instead.
443 void pwm_free(struct pwm_device *pwm)
447 EXPORT_SYMBOL_GPL(pwm_free);
450 * pwm_apply_state() - atomically apply a new state to a PWM device
452 * @state: new state to apply. This can be adjusted by the PWM driver
453 * if the requested config is not achievable, for example,
454 * ->duty_cycle and ->period might be approximated.
456 int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
460 if (!pwm || !state || !state->period ||
461 state->duty_cycle > state->period)
464 if (!memcmp(state, &pwm->state, sizeof(*state)))
467 if (pwm->chip->ops->apply) {
468 err = pwm->chip->ops->apply(pwm->chip, pwm, state);
475 * FIXME: restore the initial state in case of error.
477 if (state->polarity != pwm->state.polarity) {
478 if (!pwm->chip->ops->set_polarity)
482 * Changing the polarity of a running PWM is
483 * only allowed when the PWM driver implements
486 if (pwm->state.enabled) {
487 pwm->chip->ops->disable(pwm->chip, pwm);
488 pwm->state.enabled = false;
491 err = pwm->chip->ops->set_polarity(pwm->chip, pwm,
496 pwm->state.polarity = state->polarity;
499 if (state->period != pwm->state.period ||
500 state->duty_cycle != pwm->state.duty_cycle) {
501 err = pwm->chip->ops->config(pwm->chip, pwm,
507 pwm->state.duty_cycle = state->duty_cycle;
508 pwm->state.period = state->period;
511 if (state->enabled != pwm->state.enabled) {
512 if (state->enabled) {
513 err = pwm->chip->ops->enable(pwm->chip, pwm);
517 pwm->chip->ops->disable(pwm->chip, pwm);
520 pwm->state.enabled = state->enabled;
526 EXPORT_SYMBOL_GPL(pwm_apply_state);
529 * pwm_capture() - capture and report a PWM signal
531 * @result: structure to fill with capture result
532 * @timeout: time to wait, in milliseconds, before giving up on capture
534 * Returns: 0 on success or a negative error code on failure.
536 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
537 unsigned long timeout)
541 if (!pwm || !pwm->chip->ops)
544 if (!pwm->chip->ops->capture)
547 mutex_lock(&pwm_lock);
548 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
549 mutex_unlock(&pwm_lock);
553 EXPORT_SYMBOL_GPL(pwm_capture);
556 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
559 * This function will adjust the PWM config to the PWM arguments provided
560 * by the DT or PWM lookup table. This is particularly useful to adapt
561 * the bootloader config to the Linux one.
563 int pwm_adjust_config(struct pwm_device *pwm)
565 struct pwm_state state;
566 struct pwm_args pargs;
568 pwm_get_args(pwm, &pargs);
569 pwm_get_state(pwm, &state);
572 * If the current period is zero it means that either the PWM driver
573 * does not support initial state retrieval or the PWM has not yet
576 * In either case, we setup the new period and polarity, and assign a
580 state.duty_cycle = 0;
581 state.period = pargs.period;
582 state.polarity = pargs.polarity;
584 return pwm_apply_state(pwm, &state);
588 * Adjust the PWM duty cycle/period based on the period value provided
591 if (pargs.period != state.period) {
592 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
594 do_div(dutycycle, state.period);
595 state.duty_cycle = dutycycle;
596 state.period = pargs.period;
600 * If the polarity changed, we should also change the duty cycle.
602 if (pargs.polarity != state.polarity) {
603 state.polarity = pargs.polarity;
604 state.duty_cycle = state.period - state.duty_cycle;
607 return pwm_apply_state(pwm, &state);
609 EXPORT_SYMBOL_GPL(pwm_adjust_config);
611 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
613 struct pwm_chip *chip;
615 mutex_lock(&pwm_lock);
617 list_for_each_entry(chip, &pwm_chips, list)
618 if (chip->dev && chip->dev->of_node == np) {
619 mutex_unlock(&pwm_lock);
623 mutex_unlock(&pwm_lock);
625 return ERR_PTR(-EPROBE_DEFER);
629 * of_pwm_get() - request a PWM via the PWM framework
630 * @np: device node to get the PWM from
631 * @con_id: consumer name
633 * Returns the PWM device parsed from the phandle and index specified in the
634 * "pwms" property of a device tree node or a negative error-code on failure.
635 * Values parsed from the device tree are stored in the returned PWM device
638 * If con_id is NULL, the first PWM device listed in the "pwms" property will
639 * be requested. Otherwise the "pwm-names" property is used to do a reverse
640 * lookup of the PWM index. This also means that the "pwm-names" property
641 * becomes mandatory for devices that look up the PWM device via the con_id
644 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
645 * error code on failure.
647 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
649 struct pwm_device *pwm = NULL;
650 struct of_phandle_args args;
656 index = of_property_match_string(np, "pwm-names", con_id);
658 return ERR_PTR(index);
661 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
664 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
668 pc = of_node_to_pwmchip(args.np);
670 pr_debug("%s(): PWM chip not found\n", __func__);
675 if (args.args_count != pc->of_pwm_n_cells) {
676 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
678 pwm = ERR_PTR(-EINVAL);
682 pwm = pc->of_xlate(pc, &args);
687 * If a consumer name was not given, try to look it up from the
688 * "pwm-names" property if it exists. Otherwise use the name of
689 * the user device node.
692 err = of_property_read_string_index(np, "pwm-names", index,
701 of_node_put(args.np);
705 EXPORT_SYMBOL_GPL(of_pwm_get);
708 * pwm_add_table() - register PWM device consumers
709 * @table: array of consumers to register
710 * @num: number of consumers in table
712 void pwm_add_table(struct pwm_lookup *table, size_t num)
714 mutex_lock(&pwm_lookup_lock);
717 list_add_tail(&table->list, &pwm_lookup_list);
721 mutex_unlock(&pwm_lookup_lock);
725 * pwm_remove_table() - unregister PWM device consumers
726 * @table: array of consumers to unregister
727 * @num: number of consumers in table
729 void pwm_remove_table(struct pwm_lookup *table, size_t num)
731 mutex_lock(&pwm_lookup_lock);
734 list_del(&table->list);
738 mutex_unlock(&pwm_lookup_lock);
742 * pwm_get() - look up and request a PWM device
743 * @dev: device for PWM consumer
744 * @con_id: consumer name
746 * Lookup is first attempted using DT. If the device was not instantiated from
747 * a device tree, a PWM chip and a relative index is looked up via a table
748 * supplied by board setup code (see pwm_add_table()).
750 * Once a PWM chip has been found the specified PWM device will be requested
751 * and is ready to be used.
753 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
754 * error code on failure.
756 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
758 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
759 const char *dev_id = dev ? dev_name(dev) : NULL;
760 struct pwm_chip *chip = NULL;
761 unsigned int best = 0;
762 struct pwm_lookup *p, *chosen = NULL;
765 /* look up via DT first */
766 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
767 return of_pwm_get(dev->of_node, con_id);
770 * We look up the provider in the static table typically provided by
771 * board setup code. We first try to lookup the consumer device by
772 * name. If the consumer device was passed in as NULL or if no match
773 * was found, we try to find the consumer by directly looking it up
776 * If a match is found, the provider PWM chip is looked up by name
777 * and a PWM device is requested using the PWM device per-chip index.
779 * The lookup algorithm was shamelessly taken from the clock
782 * We do slightly fuzzy matching here:
783 * An entry with a NULL ID is assumed to be a wildcard.
784 * If an entry has a device ID, it must match
785 * If an entry has a connection ID, it must match
786 * Then we take the most specific entry - with the following order
787 * of precedence: dev+con > dev only > con only.
789 mutex_lock(&pwm_lookup_lock);
791 list_for_each_entry(p, &pwm_lookup_list, list) {
795 if (!dev_id || strcmp(p->dev_id, dev_id))
802 if (!con_id || strcmp(p->con_id, con_id))
819 pwm = ERR_PTR(-ENODEV);
823 chip = pwmchip_find_by_name(chosen->provider);
827 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
831 pwm->args.period = chosen->period;
832 pwm->args.polarity = chosen->polarity;
835 mutex_unlock(&pwm_lookup_lock);
838 EXPORT_SYMBOL_GPL(pwm_get);
841 * pwm_put() - release a PWM device
844 void pwm_put(struct pwm_device *pwm)
849 mutex_lock(&pwm_lock);
851 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
852 pr_warn("PWM device already freed\n");
856 if (pwm->chip->ops->free)
857 pwm->chip->ops->free(pwm->chip, pwm);
861 module_put(pwm->chip->ops->owner);
863 mutex_unlock(&pwm_lock);
865 EXPORT_SYMBOL_GPL(pwm_put);
867 static void devm_pwm_release(struct device *dev, void *res)
869 pwm_put(*(struct pwm_device **)res);
873 * devm_pwm_get() - resource managed pwm_get()
874 * @dev: device for PWM consumer
875 * @con_id: consumer name
877 * This function performs like pwm_get() but the acquired PWM device will
878 * automatically be released on driver detach.
880 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
881 * error code on failure.
883 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
885 struct pwm_device **ptr, *pwm;
887 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
889 return ERR_PTR(-ENOMEM);
891 pwm = pwm_get(dev, con_id);
894 devres_add(dev, ptr);
901 EXPORT_SYMBOL_GPL(devm_pwm_get);
904 * devm_of_pwm_get() - resource managed of_pwm_get()
905 * @dev: device for PWM consumer
906 * @np: device node to get the PWM from
907 * @con_id: consumer name
909 * This function performs like of_pwm_get() but the acquired PWM device will
910 * automatically be released on driver detach.
912 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
913 * error code on failure.
915 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
918 struct pwm_device **ptr, *pwm;
920 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
922 return ERR_PTR(-ENOMEM);
924 pwm = of_pwm_get(np, con_id);
927 devres_add(dev, ptr);
934 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
936 static int devm_pwm_match(struct device *dev, void *res, void *data)
938 struct pwm_device **p = res;
940 if (WARN_ON(!p || !*p))
947 * devm_pwm_put() - resource managed pwm_put()
948 * @dev: device for PWM consumer
951 * Release a PWM previously allocated using devm_pwm_get(). Calling this
952 * function is usually not needed because devm-allocated resources are
953 * automatically released on driver detach.
955 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
957 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
959 EXPORT_SYMBOL_GPL(devm_pwm_put);
962 * pwm_can_sleep() - report whether PWM access will sleep
965 * Returns: True if accessing the PWM can sleep, false otherwise.
967 bool pwm_can_sleep(struct pwm_device *pwm)
971 EXPORT_SYMBOL_GPL(pwm_can_sleep);
973 #ifdef CONFIG_DEBUG_FS
974 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
978 for (i = 0; i < chip->npwm; i++) {
979 struct pwm_device *pwm = &chip->pwms[i];
980 struct pwm_state state;
982 pwm_get_state(pwm, &state);
984 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
986 if (test_bit(PWMF_REQUESTED, &pwm->flags))
987 seq_puts(s, " requested");
990 seq_puts(s, " enabled");
992 seq_printf(s, " period: %u ns", state.period);
993 seq_printf(s, " duty: %u ns", state.duty_cycle);
994 seq_printf(s, " polarity: %s",
995 state.polarity ? "inverse" : "normal");
1001 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1003 mutex_lock(&pwm_lock);
1006 return seq_list_start(&pwm_chips, *pos);
1009 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1013 return seq_list_next(v, &pwm_chips, pos);
1016 static void pwm_seq_stop(struct seq_file *s, void *v)
1018 mutex_unlock(&pwm_lock);
1021 static int pwm_seq_show(struct seq_file *s, void *v)
1023 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1025 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1026 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1027 dev_name(chip->dev), chip->npwm,
1028 (chip->npwm != 1) ? "s" : "");
1030 if (chip->ops->dbg_show)
1031 chip->ops->dbg_show(chip, s);
1033 pwm_dbg_show(chip, s);
1038 static const struct seq_operations pwm_seq_ops = {
1039 .start = pwm_seq_start,
1040 .next = pwm_seq_next,
1041 .stop = pwm_seq_stop,
1042 .show = pwm_seq_show,
1045 static int pwm_seq_open(struct inode *inode, struct file *file)
1047 return seq_open(file, &pwm_seq_ops);
1050 static const struct file_operations pwm_debugfs_ops = {
1051 .owner = THIS_MODULE,
1052 .open = pwm_seq_open,
1054 .llseek = seq_lseek,
1055 .release = seq_release,
1058 static int __init pwm_debugfs_init(void)
1060 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1065 subsys_initcall(pwm_debugfs_init);
1066 #endif /* CONFIG_DEBUG_FS */