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];
78 radix_tree_delete(&pwm_tree, pwm->pwm);
81 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
87 static struct pwm_chip *pwmchip_find_by_name(const char *name)
89 struct pwm_chip *chip;
94 mutex_lock(&pwm_lock);
96 list_for_each_entry(chip, &pwm_chips, list) {
97 const char *chip_name = dev_name(chip->dev);
99 if (chip_name && strcmp(chip_name, name) == 0) {
100 mutex_unlock(&pwm_lock);
105 mutex_unlock(&pwm_lock);
110 static int pwm_device_request(struct pwm_device *pwm, const char *label)
114 if (test_bit(PWMF_REQUESTED, &pwm->flags))
117 if (!try_module_get(pwm->chip->ops->owner))
120 if (pwm->chip->ops->request) {
121 err = pwm->chip->ops->request(pwm->chip, pwm);
123 module_put(pwm->chip->ops->owner);
128 set_bit(PWMF_REQUESTED, &pwm->flags);
132 * FIXME: This should be removed once all PWM users properly make use
133 * of struct pwm_args to initialize the PWM device. As long as this is
134 * here, the PWM state and hardware state can get out of sync.
142 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
144 struct pwm_device *pwm;
146 if (pc->of_pwm_n_cells < 3)
147 return ERR_PTR(-EINVAL);
149 if (args->args[0] >= pc->npwm)
150 return ERR_PTR(-EINVAL);
152 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
156 pwm->args.period = args->args[1];
158 if (args->args[2] & PWM_POLARITY_INVERTED)
159 pwm->args.polarity = PWM_POLARITY_INVERSED;
161 pwm->args.polarity = PWM_POLARITY_NORMAL;
165 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
167 static struct pwm_device *
168 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
170 struct pwm_device *pwm;
172 if (pc->of_pwm_n_cells < 2)
173 return ERR_PTR(-EINVAL);
175 if (args->args[0] >= pc->npwm)
176 return ERR_PTR(-EINVAL);
178 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
182 pwm->args.period = args->args[1];
187 static void of_pwmchip_add(struct pwm_chip *chip)
189 if (!chip->dev || !chip->dev->of_node)
192 if (!chip->of_xlate) {
193 chip->of_xlate = of_pwm_simple_xlate;
194 chip->of_pwm_n_cells = 2;
197 of_node_get(chip->dev->of_node);
200 static void of_pwmchip_remove(struct pwm_chip *chip)
203 of_node_put(chip->dev->of_node);
207 * pwm_set_chip_data() - set private chip data for a PWM
209 * @data: pointer to chip-specific data
211 * Returns: 0 on success or a negative error code on failure.
213 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
218 pwm->chip_data = data;
222 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
225 * pwm_get_chip_data() - get private chip data for a PWM
228 * Returns: A pointer to the chip-private data for the PWM device.
230 void *pwm_get_chip_data(struct pwm_device *pwm)
232 return pwm ? pwm->chip_data : NULL;
234 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
237 * pwmchip_add_with_polarity() - register a new PWM chip
238 * @chip: the PWM chip to add
239 * @polarity: initial polarity of PWM channels
241 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
242 * will be used. The initial polarity for all channels is specified by the
243 * @polarity parameter.
245 * Returns: 0 on success or a negative error code on failure.
247 int pwmchip_add_with_polarity(struct pwm_chip *chip,
248 enum pwm_polarity polarity)
250 struct pwm_device *pwm;
254 if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
255 !chip->ops->enable || !chip->ops->disable || !chip->npwm)
258 mutex_lock(&pwm_lock);
260 ret = alloc_pwms(chip->base, chip->npwm);
264 chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
272 for (i = 0; i < chip->npwm; i++) {
273 pwm = &chip->pwms[i];
276 pwm->pwm = chip->base + i;
278 pwm->polarity = polarity;
279 mutex_init(&pwm->lock);
281 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
284 bitmap_set(allocated_pwms, chip->base, chip->npwm);
286 INIT_LIST_HEAD(&chip->list);
287 list_add(&chip->list, &pwm_chips);
291 if (IS_ENABLED(CONFIG_OF))
292 of_pwmchip_add(chip);
294 pwmchip_sysfs_export(chip);
297 mutex_unlock(&pwm_lock);
300 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
303 * pwmchip_add() - register a new PWM chip
304 * @chip: the PWM chip to add
306 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
307 * will be used. The initial polarity for all channels is normal.
309 * Returns: 0 on success or a negative error code on failure.
311 int pwmchip_add(struct pwm_chip *chip)
313 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
315 EXPORT_SYMBOL_GPL(pwmchip_add);
318 * pwmchip_remove() - remove a PWM chip
319 * @chip: the PWM chip to remove
321 * Removes a PWM chip. This function may return busy if the PWM chip provides
322 * a PWM device that is still requested.
324 * Returns: 0 on success or a negative error code on failure.
326 int pwmchip_remove(struct pwm_chip *chip)
331 mutex_lock(&pwm_lock);
333 for (i = 0; i < chip->npwm; i++) {
334 struct pwm_device *pwm = &chip->pwms[i];
336 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
342 list_del_init(&chip->list);
344 if (IS_ENABLED(CONFIG_OF))
345 of_pwmchip_remove(chip);
349 pwmchip_sysfs_unexport(chip);
352 mutex_unlock(&pwm_lock);
355 EXPORT_SYMBOL_GPL(pwmchip_remove);
358 * pwm_request() - request a PWM device
359 * @pwm: global PWM device index
360 * @label: PWM device label
362 * This function is deprecated, use pwm_get() instead.
364 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
367 struct pwm_device *pwm_request(int pwm, const char *label)
369 struct pwm_device *dev;
372 if (pwm < 0 || pwm >= MAX_PWMS)
373 return ERR_PTR(-EINVAL);
375 mutex_lock(&pwm_lock);
377 dev = pwm_to_device(pwm);
379 dev = ERR_PTR(-EPROBE_DEFER);
383 err = pwm_device_request(dev, label);
388 mutex_unlock(&pwm_lock);
392 EXPORT_SYMBOL_GPL(pwm_request);
395 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
397 * @index: per-chip index of the PWM to request
398 * @label: a literal description string of this PWM
400 * Returns: A pointer to the PWM device at the given index of the given PWM
401 * chip. A negative error code is returned if the index is not valid for the
402 * specified PWM chip or if the PWM device cannot be requested.
404 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
408 struct pwm_device *pwm;
411 if (!chip || index >= chip->npwm)
412 return ERR_PTR(-EINVAL);
414 mutex_lock(&pwm_lock);
415 pwm = &chip->pwms[index];
417 err = pwm_device_request(pwm, label);
421 mutex_unlock(&pwm_lock);
424 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
427 * pwm_free() - free a PWM device
430 * This function is deprecated, use pwm_put() instead.
432 void pwm_free(struct pwm_device *pwm)
436 EXPORT_SYMBOL_GPL(pwm_free);
439 * pwm_config() - change a PWM device configuration
441 * @duty_ns: "on" time (in nanoseconds)
442 * @period_ns: duration (in nanoseconds) of one cycle
444 * Returns: 0 on success or a negative error code on failure.
446 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
450 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
453 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
457 pwm->duty_cycle = duty_ns;
458 pwm->period = period_ns;
462 EXPORT_SYMBOL_GPL(pwm_config);
465 * pwm_set_polarity() - configure the polarity of a PWM signal
467 * @polarity: new polarity of the PWM signal
469 * Note that the polarity cannot be configured while the PWM device is
472 * Returns: 0 on success or a negative error code on failure.
474 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
478 if (!pwm || !pwm->chip->ops)
481 if (!pwm->chip->ops->set_polarity)
484 mutex_lock(&pwm->lock);
486 if (pwm_is_enabled(pwm)) {
491 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
495 pwm->polarity = polarity;
498 mutex_unlock(&pwm->lock);
501 EXPORT_SYMBOL_GPL(pwm_set_polarity);
504 * pwm_enable() - start a PWM output toggling
507 * Returns: 0 on success or a negative error code on failure.
509 int pwm_enable(struct pwm_device *pwm)
516 mutex_lock(&pwm->lock);
518 if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
519 err = pwm->chip->ops->enable(pwm->chip, pwm);
521 clear_bit(PWMF_ENABLED, &pwm->flags);
524 mutex_unlock(&pwm->lock);
528 EXPORT_SYMBOL_GPL(pwm_enable);
531 * pwm_disable() - stop a PWM output toggling
534 void pwm_disable(struct pwm_device *pwm)
536 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
537 pwm->chip->ops->disable(pwm->chip, pwm);
539 EXPORT_SYMBOL_GPL(pwm_disable);
541 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
543 struct pwm_chip *chip;
545 mutex_lock(&pwm_lock);
547 list_for_each_entry(chip, &pwm_chips, list)
548 if (chip->dev && chip->dev->of_node == np) {
549 mutex_unlock(&pwm_lock);
553 mutex_unlock(&pwm_lock);
555 return ERR_PTR(-EPROBE_DEFER);
559 * of_pwm_get() - request a PWM via the PWM framework
560 * @np: device node to get the PWM from
561 * @con_id: consumer name
563 * Returns the PWM device parsed from the phandle and index specified in the
564 * "pwms" property of a device tree node or a negative error-code on failure.
565 * Values parsed from the device tree are stored in the returned PWM device
568 * If con_id is NULL, the first PWM device listed in the "pwms" property will
569 * be requested. Otherwise the "pwm-names" property is used to do a reverse
570 * lookup of the PWM index. This also means that the "pwm-names" property
571 * becomes mandatory for devices that look up the PWM device via the con_id
574 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
575 * error code on failure.
577 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
579 struct pwm_device *pwm = NULL;
580 struct of_phandle_args args;
586 index = of_property_match_string(np, "pwm-names", con_id);
588 return ERR_PTR(index);
591 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
594 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
598 pc = of_node_to_pwmchip(args.np);
600 pr_debug("%s(): PWM chip not found\n", __func__);
605 if (args.args_count != pc->of_pwm_n_cells) {
606 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
608 pwm = ERR_PTR(-EINVAL);
612 pwm = pc->of_xlate(pc, &args);
617 * If a consumer name was not given, try to look it up from the
618 * "pwm-names" property if it exists. Otherwise use the name of
619 * the user device node.
622 err = of_property_read_string_index(np, "pwm-names", index,
631 of_node_put(args.np);
635 EXPORT_SYMBOL_GPL(of_pwm_get);
638 * pwm_add_table() - register PWM device consumers
639 * @table: array of consumers to register
640 * @num: number of consumers in table
642 void pwm_add_table(struct pwm_lookup *table, size_t num)
644 mutex_lock(&pwm_lookup_lock);
647 list_add_tail(&table->list, &pwm_lookup_list);
651 mutex_unlock(&pwm_lookup_lock);
655 * pwm_remove_table() - unregister PWM device consumers
656 * @table: array of consumers to unregister
657 * @num: number of consumers in table
659 void pwm_remove_table(struct pwm_lookup *table, size_t num)
661 mutex_lock(&pwm_lookup_lock);
664 list_del(&table->list);
668 mutex_unlock(&pwm_lookup_lock);
672 * pwm_get() - look up and request a PWM device
673 * @dev: device for PWM consumer
674 * @con_id: consumer name
676 * Lookup is first attempted using DT. If the device was not instantiated from
677 * a device tree, a PWM chip and a relative index is looked up via a table
678 * supplied by board setup code (see pwm_add_table()).
680 * Once a PWM chip has been found the specified PWM device will be requested
681 * and is ready to be used.
683 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
684 * error code on failure.
686 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
688 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
689 const char *dev_id = dev ? dev_name(dev) : NULL;
690 struct pwm_chip *chip = NULL;
691 unsigned int best = 0;
692 struct pwm_lookup *p, *chosen = NULL;
695 /* look up via DT first */
696 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
697 return of_pwm_get(dev->of_node, con_id);
700 * We look up the provider in the static table typically provided by
701 * board setup code. We first try to lookup the consumer device by
702 * name. If the consumer device was passed in as NULL or if no match
703 * was found, we try to find the consumer by directly looking it up
706 * If a match is found, the provider PWM chip is looked up by name
707 * and a PWM device is requested using the PWM device per-chip index.
709 * The lookup algorithm was shamelessly taken from the clock
712 * We do slightly fuzzy matching here:
713 * An entry with a NULL ID is assumed to be a wildcard.
714 * If an entry has a device ID, it must match
715 * If an entry has a connection ID, it must match
716 * Then we take the most specific entry - with the following order
717 * of precedence: dev+con > dev only > con only.
719 mutex_lock(&pwm_lookup_lock);
721 list_for_each_entry(p, &pwm_lookup_list, list) {
725 if (!dev_id || strcmp(p->dev_id, dev_id))
732 if (!con_id || strcmp(p->con_id, con_id))
749 pwm = ERR_PTR(-ENODEV);
753 chip = pwmchip_find_by_name(chosen->provider);
757 pwm->args.period = chosen->period;
758 pwm->args.polarity = chosen->polarity;
760 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
765 mutex_unlock(&pwm_lookup_lock);
768 EXPORT_SYMBOL_GPL(pwm_get);
771 * pwm_put() - release a PWM device
774 void pwm_put(struct pwm_device *pwm)
779 mutex_lock(&pwm_lock);
781 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
782 pr_warn("PWM device already freed\n");
786 if (pwm->chip->ops->free)
787 pwm->chip->ops->free(pwm->chip, pwm);
791 module_put(pwm->chip->ops->owner);
793 mutex_unlock(&pwm_lock);
795 EXPORT_SYMBOL_GPL(pwm_put);
797 static void devm_pwm_release(struct device *dev, void *res)
799 pwm_put(*(struct pwm_device **)res);
803 * devm_pwm_get() - resource managed pwm_get()
804 * @dev: device for PWM consumer
805 * @con_id: consumer name
807 * This function performs like pwm_get() but the acquired PWM device will
808 * automatically be released on driver detach.
810 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
811 * error code on failure.
813 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
815 struct pwm_device **ptr, *pwm;
817 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
819 return ERR_PTR(-ENOMEM);
821 pwm = pwm_get(dev, con_id);
824 devres_add(dev, ptr);
831 EXPORT_SYMBOL_GPL(devm_pwm_get);
834 * devm_of_pwm_get() - resource managed of_pwm_get()
835 * @dev: device for PWM consumer
836 * @np: device node to get the PWM from
837 * @con_id: consumer name
839 * This function performs like of_pwm_get() but the acquired PWM device will
840 * automatically be released on driver detach.
842 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
843 * error code on failure.
845 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
848 struct pwm_device **ptr, *pwm;
850 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
852 return ERR_PTR(-ENOMEM);
854 pwm = of_pwm_get(np, con_id);
857 devres_add(dev, ptr);
864 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
866 static int devm_pwm_match(struct device *dev, void *res, void *data)
868 struct pwm_device **p = res;
870 if (WARN_ON(!p || !*p))
877 * devm_pwm_put() - resource managed pwm_put()
878 * @dev: device for PWM consumer
881 * Release a PWM previously allocated using devm_pwm_get(). Calling this
882 * function is usually not needed because devm-allocated resources are
883 * automatically released on driver detach.
885 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
887 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
889 EXPORT_SYMBOL_GPL(devm_pwm_put);
892 * pwm_can_sleep() - report whether PWM access will sleep
895 * Returns: True if accessing the PWM can sleep, false otherwise.
897 bool pwm_can_sleep(struct pwm_device *pwm)
901 EXPORT_SYMBOL_GPL(pwm_can_sleep);
903 #ifdef CONFIG_DEBUG_FS
904 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
908 for (i = 0; i < chip->npwm; i++) {
909 struct pwm_device *pwm = &chip->pwms[i];
911 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
913 if (test_bit(PWMF_REQUESTED, &pwm->flags))
914 seq_puts(s, " requested");
916 if (pwm_is_enabled(pwm))
917 seq_puts(s, " enabled");
923 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
925 mutex_lock(&pwm_lock);
928 return seq_list_start(&pwm_chips, *pos);
931 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
935 return seq_list_next(v, &pwm_chips, pos);
938 static void pwm_seq_stop(struct seq_file *s, void *v)
940 mutex_unlock(&pwm_lock);
943 static int pwm_seq_show(struct seq_file *s, void *v)
945 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
947 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
948 chip->dev->bus ? chip->dev->bus->name : "no-bus",
949 dev_name(chip->dev), chip->npwm,
950 (chip->npwm != 1) ? "s" : "");
952 if (chip->ops->dbg_show)
953 chip->ops->dbg_show(chip, s);
955 pwm_dbg_show(chip, s);
960 static const struct seq_operations pwm_seq_ops = {
961 .start = pwm_seq_start,
962 .next = pwm_seq_next,
963 .stop = pwm_seq_stop,
964 .show = pwm_seq_show,
967 static int pwm_seq_open(struct inode *inode, struct file *file)
969 return seq_open(file, &pwm_seq_ops);
972 static const struct file_operations pwm_debugfs_ops = {
973 .owner = THIS_MODULE,
974 .open = pwm_seq_open,
977 .release = seq_release,
980 static int __init pwm_debugfs_init(void)
982 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
987 subsys_initcall(pwm_debugfs_init);
988 #endif /* CONFIG_DEBUG_FS */