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 pwmchip_sysfs_unexport_children(chip);
333 mutex_lock(&pwm_lock);
335 for (i = 0; i < chip->npwm; i++) {
336 struct pwm_device *pwm = &chip->pwms[i];
338 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
344 list_del_init(&chip->list);
346 if (IS_ENABLED(CONFIG_OF))
347 of_pwmchip_remove(chip);
351 pwmchip_sysfs_unexport(chip);
354 mutex_unlock(&pwm_lock);
357 EXPORT_SYMBOL_GPL(pwmchip_remove);
360 * pwm_request() - request a PWM device
361 * @pwm: global PWM device index
362 * @label: PWM device label
364 * This function is deprecated, use pwm_get() instead.
366 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
369 struct pwm_device *pwm_request(int pwm, const char *label)
371 struct pwm_device *dev;
374 if (pwm < 0 || pwm >= MAX_PWMS)
375 return ERR_PTR(-EINVAL);
377 mutex_lock(&pwm_lock);
379 dev = pwm_to_device(pwm);
381 dev = ERR_PTR(-EPROBE_DEFER);
385 err = pwm_device_request(dev, label);
390 mutex_unlock(&pwm_lock);
394 EXPORT_SYMBOL_GPL(pwm_request);
397 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
399 * @index: per-chip index of the PWM to request
400 * @label: a literal description string of this PWM
402 * Returns: A pointer to the PWM device at the given index of the given PWM
403 * chip. A negative error code is returned if the index is not valid for the
404 * specified PWM chip or if the PWM device cannot be requested.
406 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
410 struct pwm_device *pwm;
413 if (!chip || index >= chip->npwm)
414 return ERR_PTR(-EINVAL);
416 mutex_lock(&pwm_lock);
417 pwm = &chip->pwms[index];
419 err = pwm_device_request(pwm, label);
423 mutex_unlock(&pwm_lock);
426 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
429 * pwm_free() - free a PWM device
432 * This function is deprecated, use pwm_put() instead.
434 void pwm_free(struct pwm_device *pwm)
438 EXPORT_SYMBOL_GPL(pwm_free);
441 * pwm_config() - change a PWM device configuration
443 * @duty_ns: "on" time (in nanoseconds)
444 * @period_ns: duration (in nanoseconds) of one cycle
446 * Returns: 0 on success or a negative error code on failure.
448 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
452 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
455 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
459 pwm->duty_cycle = duty_ns;
460 pwm->period = period_ns;
464 EXPORT_SYMBOL_GPL(pwm_config);
467 * pwm_set_polarity() - configure the polarity of a PWM signal
469 * @polarity: new polarity of the PWM signal
471 * Note that the polarity cannot be configured while the PWM device is
474 * Returns: 0 on success or a negative error code on failure.
476 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
480 if (!pwm || !pwm->chip->ops)
483 if (!pwm->chip->ops->set_polarity)
486 mutex_lock(&pwm->lock);
488 if (pwm_is_enabled(pwm)) {
493 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
497 pwm->polarity = polarity;
500 mutex_unlock(&pwm->lock);
503 EXPORT_SYMBOL_GPL(pwm_set_polarity);
506 * pwm_enable() - start a PWM output toggling
509 * Returns: 0 on success or a negative error code on failure.
511 int pwm_enable(struct pwm_device *pwm)
518 mutex_lock(&pwm->lock);
520 if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
521 err = pwm->chip->ops->enable(pwm->chip, pwm);
523 clear_bit(PWMF_ENABLED, &pwm->flags);
526 mutex_unlock(&pwm->lock);
530 EXPORT_SYMBOL_GPL(pwm_enable);
533 * pwm_disable() - stop a PWM output toggling
536 void pwm_disable(struct pwm_device *pwm)
538 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
539 pwm->chip->ops->disable(pwm->chip, pwm);
541 EXPORT_SYMBOL_GPL(pwm_disable);
543 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
545 struct pwm_chip *chip;
547 mutex_lock(&pwm_lock);
549 list_for_each_entry(chip, &pwm_chips, list)
550 if (chip->dev && chip->dev->of_node == np) {
551 mutex_unlock(&pwm_lock);
555 mutex_unlock(&pwm_lock);
557 return ERR_PTR(-EPROBE_DEFER);
561 * of_pwm_get() - request a PWM via the PWM framework
562 * @np: device node to get the PWM from
563 * @con_id: consumer name
565 * Returns the PWM device parsed from the phandle and index specified in the
566 * "pwms" property of a device tree node or a negative error-code on failure.
567 * Values parsed from the device tree are stored in the returned PWM device
570 * If con_id is NULL, the first PWM device listed in the "pwms" property will
571 * be requested. Otherwise the "pwm-names" property is used to do a reverse
572 * lookup of the PWM index. This also means that the "pwm-names" property
573 * becomes mandatory for devices that look up the PWM device via the con_id
576 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
577 * error code on failure.
579 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
581 struct pwm_device *pwm = NULL;
582 struct of_phandle_args args;
588 index = of_property_match_string(np, "pwm-names", con_id);
590 return ERR_PTR(index);
593 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
596 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
600 pc = of_node_to_pwmchip(args.np);
602 pr_debug("%s(): PWM chip not found\n", __func__);
607 if (args.args_count != pc->of_pwm_n_cells) {
608 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
610 pwm = ERR_PTR(-EINVAL);
614 pwm = pc->of_xlate(pc, &args);
619 * If a consumer name was not given, try to look it up from the
620 * "pwm-names" property if it exists. Otherwise use the name of
621 * the user device node.
624 err = of_property_read_string_index(np, "pwm-names", index,
633 of_node_put(args.np);
637 EXPORT_SYMBOL_GPL(of_pwm_get);
640 * pwm_add_table() - register PWM device consumers
641 * @table: array of consumers to register
642 * @num: number of consumers in table
644 void pwm_add_table(struct pwm_lookup *table, size_t num)
646 mutex_lock(&pwm_lookup_lock);
649 list_add_tail(&table->list, &pwm_lookup_list);
653 mutex_unlock(&pwm_lookup_lock);
657 * pwm_remove_table() - unregister PWM device consumers
658 * @table: array of consumers to unregister
659 * @num: number of consumers in table
661 void pwm_remove_table(struct pwm_lookup *table, size_t num)
663 mutex_lock(&pwm_lookup_lock);
666 list_del(&table->list);
670 mutex_unlock(&pwm_lookup_lock);
674 * pwm_get() - look up and request a PWM device
675 * @dev: device for PWM consumer
676 * @con_id: consumer name
678 * Lookup is first attempted using DT. If the device was not instantiated from
679 * a device tree, a PWM chip and a relative index is looked up via a table
680 * supplied by board setup code (see pwm_add_table()).
682 * Once a PWM chip has been found the specified PWM device will be requested
683 * and is ready to be used.
685 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
686 * error code on failure.
688 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
690 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
691 const char *dev_id = dev ? dev_name(dev) : NULL;
692 struct pwm_chip *chip = NULL;
693 unsigned int best = 0;
694 struct pwm_lookup *p, *chosen = NULL;
697 /* look up via DT first */
698 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
699 return of_pwm_get(dev->of_node, con_id);
702 * We look up the provider in the static table typically provided by
703 * board setup code. We first try to lookup the consumer device by
704 * name. If the consumer device was passed in as NULL or if no match
705 * was found, we try to find the consumer by directly looking it up
708 * If a match is found, the provider PWM chip is looked up by name
709 * and a PWM device is requested using the PWM device per-chip index.
711 * The lookup algorithm was shamelessly taken from the clock
714 * We do slightly fuzzy matching here:
715 * An entry with a NULL ID is assumed to be a wildcard.
716 * If an entry has a device ID, it must match
717 * If an entry has a connection ID, it must match
718 * Then we take the most specific entry - with the following order
719 * of precedence: dev+con > dev only > con only.
721 mutex_lock(&pwm_lookup_lock);
723 list_for_each_entry(p, &pwm_lookup_list, list) {
727 if (!dev_id || strcmp(p->dev_id, dev_id))
734 if (!con_id || strcmp(p->con_id, con_id))
751 pwm = ERR_PTR(-ENODEV);
755 chip = pwmchip_find_by_name(chosen->provider);
759 pwm->args.period = chosen->period;
760 pwm->args.polarity = chosen->polarity;
762 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
767 mutex_unlock(&pwm_lookup_lock);
770 EXPORT_SYMBOL_GPL(pwm_get);
773 * pwm_put() - release a PWM device
776 void pwm_put(struct pwm_device *pwm)
781 mutex_lock(&pwm_lock);
783 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
784 pr_warn("PWM device already freed\n");
788 if (pwm->chip->ops->free)
789 pwm->chip->ops->free(pwm->chip, pwm);
793 module_put(pwm->chip->ops->owner);
795 mutex_unlock(&pwm_lock);
797 EXPORT_SYMBOL_GPL(pwm_put);
799 static void devm_pwm_release(struct device *dev, void *res)
801 pwm_put(*(struct pwm_device **)res);
805 * devm_pwm_get() - resource managed pwm_get()
806 * @dev: device for PWM consumer
807 * @con_id: consumer name
809 * This function performs like pwm_get() but the acquired PWM device will
810 * automatically be released on driver detach.
812 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
813 * error code on failure.
815 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
817 struct pwm_device **ptr, *pwm;
819 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
821 return ERR_PTR(-ENOMEM);
823 pwm = pwm_get(dev, con_id);
826 devres_add(dev, ptr);
833 EXPORT_SYMBOL_GPL(devm_pwm_get);
836 * devm_of_pwm_get() - resource managed of_pwm_get()
837 * @dev: device for PWM consumer
838 * @np: device node to get the PWM from
839 * @con_id: consumer name
841 * This function performs like of_pwm_get() but the acquired PWM device will
842 * automatically be released on driver detach.
844 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
845 * error code on failure.
847 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
850 struct pwm_device **ptr, *pwm;
852 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
854 return ERR_PTR(-ENOMEM);
856 pwm = of_pwm_get(np, con_id);
859 devres_add(dev, ptr);
866 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
868 static int devm_pwm_match(struct device *dev, void *res, void *data)
870 struct pwm_device **p = res;
872 if (WARN_ON(!p || !*p))
879 * devm_pwm_put() - resource managed pwm_put()
880 * @dev: device for PWM consumer
883 * Release a PWM previously allocated using devm_pwm_get(). Calling this
884 * function is usually not needed because devm-allocated resources are
885 * automatically released on driver detach.
887 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
889 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
891 EXPORT_SYMBOL_GPL(devm_pwm_put);
894 * pwm_can_sleep() - report whether PWM access will sleep
897 * Returns: True if accessing the PWM can sleep, false otherwise.
899 bool pwm_can_sleep(struct pwm_device *pwm)
903 EXPORT_SYMBOL_GPL(pwm_can_sleep);
905 #ifdef CONFIG_DEBUG_FS
906 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
910 for (i = 0; i < chip->npwm; i++) {
911 struct pwm_device *pwm = &chip->pwms[i];
913 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
915 if (test_bit(PWMF_REQUESTED, &pwm->flags))
916 seq_puts(s, " requested");
918 if (pwm_is_enabled(pwm))
919 seq_puts(s, " enabled");
925 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
927 mutex_lock(&pwm_lock);
930 return seq_list_start(&pwm_chips, *pos);
933 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
937 return seq_list_next(v, &pwm_chips, pos);
940 static void pwm_seq_stop(struct seq_file *s, void *v)
942 mutex_unlock(&pwm_lock);
945 static int pwm_seq_show(struct seq_file *s, void *v)
947 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
949 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
950 chip->dev->bus ? chip->dev->bus->name : "no-bus",
951 dev_name(chip->dev), chip->npwm,
952 (chip->npwm != 1) ? "s" : "");
954 if (chip->ops->dbg_show)
955 chip->ops->dbg_show(chip, s);
957 pwm_dbg_show(chip, s);
962 static const struct seq_operations pwm_seq_ops = {
963 .start = pwm_seq_start,
964 .next = pwm_seq_next,
965 .stop = pwm_seq_stop,
966 .show = pwm_seq_show,
969 static int pwm_seq_open(struct inode *inode, struct file *file)
971 return seq_open(file, &pwm_seq_ops);
974 static const struct file_operations pwm_debugfs_ops = {
975 .owner = THIS_MODULE,
976 .open = pwm_seq_open,
979 .release = seq_release,
982 static int __init pwm_debugfs_init(void)
984 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
989 subsys_initcall(pwm_debugfs_init);
990 #endif /* CONFIG_DEBUG_FS */