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);
231 * pwmchip_add_with_polarity() - register a new PWM chip
232 * @chip: the PWM chip to add
233 * @polarity: initial polarity of PWM channels
235 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
236 * will be used. The initial polarity for all channels is specified by the
237 * @polarity parameter.
239 * Returns: 0 on success or a negative error code on failure.
241 int pwmchip_add_with_polarity(struct pwm_chip *chip,
242 enum pwm_polarity polarity)
244 struct pwm_device *pwm;
248 if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
249 !chip->ops->enable || !chip->ops->disable || !chip->npwm)
252 mutex_lock(&pwm_lock);
254 ret = alloc_pwms(chip->base, chip->npwm);
258 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
266 for (i = 0; i < chip->npwm; i++) {
267 pwm = &chip->pwms[i];
270 pwm->pwm = chip->base + i;
272 pwm->state.polarity = polarity;
274 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
277 bitmap_set(allocated_pwms, chip->base, chip->npwm);
279 INIT_LIST_HEAD(&chip->list);
280 list_add(&chip->list, &pwm_chips);
284 if (IS_ENABLED(CONFIG_OF))
285 of_pwmchip_add(chip);
287 pwmchip_sysfs_export(chip);
290 mutex_unlock(&pwm_lock);
293 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
296 * pwmchip_add() - register a new PWM chip
297 * @chip: the PWM chip to add
299 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
300 * will be used. The initial polarity for all channels is normal.
302 * Returns: 0 on success or a negative error code on failure.
304 int pwmchip_add(struct pwm_chip *chip)
306 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
308 EXPORT_SYMBOL_GPL(pwmchip_add);
311 * pwmchip_remove() - remove a PWM chip
312 * @chip: the PWM chip to remove
314 * Removes a PWM chip. This function may return busy if the PWM chip provides
315 * a PWM device that is still requested.
317 * Returns: 0 on success or a negative error code on failure.
319 int pwmchip_remove(struct pwm_chip *chip)
324 pwmchip_sysfs_unexport_children(chip);
326 mutex_lock(&pwm_lock);
328 for (i = 0; i < chip->npwm; i++) {
329 struct pwm_device *pwm = &chip->pwms[i];
331 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
337 list_del_init(&chip->list);
339 if (IS_ENABLED(CONFIG_OF))
340 of_pwmchip_remove(chip);
344 pwmchip_sysfs_unexport(chip);
347 mutex_unlock(&pwm_lock);
350 EXPORT_SYMBOL_GPL(pwmchip_remove);
353 * pwm_request() - request a PWM device
354 * @pwm: global PWM device index
355 * @label: PWM device label
357 * This function is deprecated, use pwm_get() instead.
359 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
362 struct pwm_device *pwm_request(int pwm, const char *label)
364 struct pwm_device *dev;
367 if (pwm < 0 || pwm >= MAX_PWMS)
368 return ERR_PTR(-EINVAL);
370 mutex_lock(&pwm_lock);
372 dev = pwm_to_device(pwm);
374 dev = ERR_PTR(-EPROBE_DEFER);
378 err = pwm_device_request(dev, label);
383 mutex_unlock(&pwm_lock);
387 EXPORT_SYMBOL_GPL(pwm_request);
390 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
392 * @index: per-chip index of the PWM to request
393 * @label: a literal description string of this PWM
395 * Returns: A pointer to the PWM device at the given index of the given PWM
396 * chip. A negative error code is returned if the index is not valid for the
397 * specified PWM chip or if the PWM device cannot be requested.
399 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
403 struct pwm_device *pwm;
406 if (!chip || index >= chip->npwm)
407 return ERR_PTR(-EINVAL);
409 mutex_lock(&pwm_lock);
410 pwm = &chip->pwms[index];
412 err = pwm_device_request(pwm, label);
416 mutex_unlock(&pwm_lock);
419 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
422 * pwm_free() - free a PWM device
425 * This function is deprecated, use pwm_put() instead.
427 void pwm_free(struct pwm_device *pwm)
431 EXPORT_SYMBOL_GPL(pwm_free);
434 * pwm_config() - change a PWM device configuration
436 * @duty_ns: "on" time (in nanoseconds)
437 * @period_ns: duration (in nanoseconds) of one cycle
439 * Returns: 0 on success or a negative error code on failure.
441 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
445 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
448 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
452 pwm->state.duty_cycle = duty_ns;
453 pwm->state.period = period_ns;
457 EXPORT_SYMBOL_GPL(pwm_config);
460 * pwm_set_polarity() - configure the polarity of a PWM signal
462 * @polarity: new polarity of the PWM signal
464 * Note that the polarity cannot be configured while the PWM device is
467 * Returns: 0 on success or a negative error code on failure.
469 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
473 if (!pwm || !pwm->chip->ops)
476 if (!pwm->chip->ops->set_polarity)
479 if (pwm_is_enabled(pwm))
482 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
486 pwm->state.polarity = polarity;
490 EXPORT_SYMBOL_GPL(pwm_set_polarity);
493 * pwm_enable() - start a PWM output toggling
496 * Returns: 0 on success or a negative error code on failure.
498 int pwm_enable(struct pwm_device *pwm)
505 if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
506 err = pwm->chip->ops->enable(pwm->chip, pwm);
508 clear_bit(PWMF_ENABLED, &pwm->flags);
513 EXPORT_SYMBOL_GPL(pwm_enable);
516 * pwm_disable() - stop a PWM output toggling
519 void pwm_disable(struct pwm_device *pwm)
521 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
522 pwm->chip->ops->disable(pwm->chip, pwm);
524 EXPORT_SYMBOL_GPL(pwm_disable);
526 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
528 struct pwm_chip *chip;
530 mutex_lock(&pwm_lock);
532 list_for_each_entry(chip, &pwm_chips, list)
533 if (chip->dev && chip->dev->of_node == np) {
534 mutex_unlock(&pwm_lock);
538 mutex_unlock(&pwm_lock);
540 return ERR_PTR(-EPROBE_DEFER);
544 * of_pwm_get() - request a PWM via the PWM framework
545 * @np: device node to get the PWM from
546 * @con_id: consumer name
548 * Returns the PWM device parsed from the phandle and index specified in the
549 * "pwms" property of a device tree node or a negative error-code on failure.
550 * Values parsed from the device tree are stored in the returned PWM device
553 * If con_id is NULL, the first PWM device listed in the "pwms" property will
554 * be requested. Otherwise the "pwm-names" property is used to do a reverse
555 * lookup of the PWM index. This also means that the "pwm-names" property
556 * becomes mandatory for devices that look up the PWM device via the con_id
559 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
560 * error code on failure.
562 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
564 struct pwm_device *pwm = NULL;
565 struct of_phandle_args args;
571 index = of_property_match_string(np, "pwm-names", con_id);
573 return ERR_PTR(index);
576 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
579 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
583 pc = of_node_to_pwmchip(args.np);
585 pr_debug("%s(): PWM chip not found\n", __func__);
590 if (args.args_count != pc->of_pwm_n_cells) {
591 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
593 pwm = ERR_PTR(-EINVAL);
597 pwm = pc->of_xlate(pc, &args);
602 * If a consumer name was not given, try to look it up from the
603 * "pwm-names" property if it exists. Otherwise use the name of
604 * the user device node.
607 err = of_property_read_string_index(np, "pwm-names", index,
616 of_node_put(args.np);
620 EXPORT_SYMBOL_GPL(of_pwm_get);
623 * pwm_add_table() - register PWM device consumers
624 * @table: array of consumers to register
625 * @num: number of consumers in table
627 void pwm_add_table(struct pwm_lookup *table, size_t num)
629 mutex_lock(&pwm_lookup_lock);
632 list_add_tail(&table->list, &pwm_lookup_list);
636 mutex_unlock(&pwm_lookup_lock);
640 * pwm_remove_table() - unregister PWM device consumers
641 * @table: array of consumers to unregister
642 * @num: number of consumers in table
644 void pwm_remove_table(struct pwm_lookup *table, size_t num)
646 mutex_lock(&pwm_lookup_lock);
649 list_del(&table->list);
653 mutex_unlock(&pwm_lookup_lock);
657 * pwm_get() - look up and request a PWM device
658 * @dev: device for PWM consumer
659 * @con_id: consumer name
661 * Lookup is first attempted using DT. If the device was not instantiated from
662 * a device tree, a PWM chip and a relative index is looked up via a table
663 * supplied by board setup code (see pwm_add_table()).
665 * Once a PWM chip has been found the specified PWM device will be requested
666 * and is ready to be used.
668 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
669 * error code on failure.
671 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
673 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
674 const char *dev_id = dev ? dev_name(dev) : NULL;
675 struct pwm_chip *chip = NULL;
676 unsigned int best = 0;
677 struct pwm_lookup *p, *chosen = NULL;
680 /* look up via DT first */
681 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
682 return of_pwm_get(dev->of_node, con_id);
685 * We look up the provider in the static table typically provided by
686 * board setup code. We first try to lookup the consumer device by
687 * name. If the consumer device was passed in as NULL or if no match
688 * was found, we try to find the consumer by directly looking it up
691 * If a match is found, the provider PWM chip is looked up by name
692 * and a PWM device is requested using the PWM device per-chip index.
694 * The lookup algorithm was shamelessly taken from the clock
697 * We do slightly fuzzy matching here:
698 * An entry with a NULL ID is assumed to be a wildcard.
699 * If an entry has a device ID, it must match
700 * If an entry has a connection ID, it must match
701 * Then we take the most specific entry - with the following order
702 * of precedence: dev+con > dev only > con only.
704 mutex_lock(&pwm_lookup_lock);
706 list_for_each_entry(p, &pwm_lookup_list, list) {
710 if (!dev_id || strcmp(p->dev_id, dev_id))
717 if (!con_id || strcmp(p->con_id, con_id))
734 pwm = ERR_PTR(-ENODEV);
738 chip = pwmchip_find_by_name(chosen->provider);
742 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
746 pwm->args.period = chosen->period;
747 pwm->args.polarity = chosen->polarity;
750 mutex_unlock(&pwm_lookup_lock);
753 EXPORT_SYMBOL_GPL(pwm_get);
756 * pwm_put() - release a PWM device
759 void pwm_put(struct pwm_device *pwm)
764 mutex_lock(&pwm_lock);
766 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
767 pr_warn("PWM device already freed\n");
771 if (pwm->chip->ops->free)
772 pwm->chip->ops->free(pwm->chip, pwm);
776 module_put(pwm->chip->ops->owner);
778 mutex_unlock(&pwm_lock);
780 EXPORT_SYMBOL_GPL(pwm_put);
782 static void devm_pwm_release(struct device *dev, void *res)
784 pwm_put(*(struct pwm_device **)res);
788 * devm_pwm_get() - resource managed pwm_get()
789 * @dev: device for PWM consumer
790 * @con_id: consumer name
792 * This function performs like pwm_get() but the acquired PWM device will
793 * automatically be released on driver detach.
795 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
796 * error code on failure.
798 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
800 struct pwm_device **ptr, *pwm;
802 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
804 return ERR_PTR(-ENOMEM);
806 pwm = pwm_get(dev, con_id);
809 devres_add(dev, ptr);
816 EXPORT_SYMBOL_GPL(devm_pwm_get);
819 * devm_of_pwm_get() - resource managed of_pwm_get()
820 * @dev: device for PWM consumer
821 * @np: device node to get the PWM from
822 * @con_id: consumer name
824 * This function performs like of_pwm_get() but the acquired PWM device will
825 * automatically be released on driver detach.
827 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
828 * error code on failure.
830 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
833 struct pwm_device **ptr, *pwm;
835 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
837 return ERR_PTR(-ENOMEM);
839 pwm = of_pwm_get(np, con_id);
842 devres_add(dev, ptr);
849 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
851 static int devm_pwm_match(struct device *dev, void *res, void *data)
853 struct pwm_device **p = res;
855 if (WARN_ON(!p || !*p))
862 * devm_pwm_put() - resource managed pwm_put()
863 * @dev: device for PWM consumer
866 * Release a PWM previously allocated using devm_pwm_get(). Calling this
867 * function is usually not needed because devm-allocated resources are
868 * automatically released on driver detach.
870 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
872 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
874 EXPORT_SYMBOL_GPL(devm_pwm_put);
877 * pwm_can_sleep() - report whether PWM access will sleep
880 * Returns: True if accessing the PWM can sleep, false otherwise.
882 bool pwm_can_sleep(struct pwm_device *pwm)
886 EXPORT_SYMBOL_GPL(pwm_can_sleep);
888 #ifdef CONFIG_DEBUG_FS
889 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
893 for (i = 0; i < chip->npwm; i++) {
894 struct pwm_device *pwm = &chip->pwms[i];
896 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
898 if (test_bit(PWMF_REQUESTED, &pwm->flags))
899 seq_puts(s, " requested");
901 if (pwm_is_enabled(pwm))
902 seq_puts(s, " enabled");
908 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
910 mutex_lock(&pwm_lock);
913 return seq_list_start(&pwm_chips, *pos);
916 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
920 return seq_list_next(v, &pwm_chips, pos);
923 static void pwm_seq_stop(struct seq_file *s, void *v)
925 mutex_unlock(&pwm_lock);
928 static int pwm_seq_show(struct seq_file *s, void *v)
930 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
932 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
933 chip->dev->bus ? chip->dev->bus->name : "no-bus",
934 dev_name(chip->dev), chip->npwm,
935 (chip->npwm != 1) ? "s" : "");
937 if (chip->ops->dbg_show)
938 chip->ops->dbg_show(chip, s);
940 pwm_dbg_show(chip, s);
945 static const struct seq_operations pwm_seq_ops = {
946 .start = pwm_seq_start,
947 .next = pwm_seq_next,
948 .stop = pwm_seq_stop,
949 .show = pwm_seq_show,
952 static int pwm_seq_open(struct inode *inode, struct file *file)
954 return seq_open(file, &pwm_seq_ops);
957 static const struct file_operations pwm_debugfs_ops = {
958 .owner = THIS_MODULE,
959 .open = pwm_seq_open,
962 .release = seq_release,
965 static int __init pwm_debugfs_init(void)
967 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
972 subsys_initcall(pwm_debugfs_init);
973 #endif /* CONFIG_DEBUG_FS */