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);
135 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
137 struct pwm_device *pwm;
139 if (pc->of_pwm_n_cells < 3)
140 return ERR_PTR(-EINVAL);
142 if (args->args[0] >= pc->npwm)
143 return ERR_PTR(-EINVAL);
145 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
149 pwm_set_period(pwm, args->args[1]);
151 if (args->args[2] & PWM_POLARITY_INVERTED)
152 pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
154 pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
158 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
160 static struct pwm_device *
161 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
163 struct pwm_device *pwm;
165 if (pc->of_pwm_n_cells < 2)
166 return ERR_PTR(-EINVAL);
168 if (args->args[0] >= pc->npwm)
169 return ERR_PTR(-EINVAL);
171 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
175 pwm_set_period(pwm, args->args[1]);
180 static void of_pwmchip_add(struct pwm_chip *chip)
182 if (!chip->dev || !chip->dev->of_node)
185 if (!chip->of_xlate) {
186 chip->of_xlate = of_pwm_simple_xlate;
187 chip->of_pwm_n_cells = 2;
190 of_node_get(chip->dev->of_node);
193 static void of_pwmchip_remove(struct pwm_chip *chip)
196 of_node_put(chip->dev->of_node);
200 * pwm_set_chip_data() - set private chip data for a PWM
202 * @data: pointer to chip-specific data
204 * Returns: 0 on success or a negative error code on failure.
206 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
211 pwm->chip_data = data;
215 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
218 * pwm_get_chip_data() - get private chip data for a PWM
221 * Returns: A pointer to the chip-private data for the PWM device.
223 void *pwm_get_chip_data(struct pwm_device *pwm)
225 return pwm ? pwm->chip_data : NULL;
227 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
230 * pwmchip_add_with_polarity() - register a new PWM chip
231 * @chip: the PWM chip to add
232 * @polarity: initial polarity of PWM channels
234 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
235 * will be used. The initial polarity for all channels is specified by the
236 * @polarity parameter.
238 * Returns: 0 on success or a negative error code on failure.
240 int pwmchip_add_with_polarity(struct pwm_chip *chip,
241 enum pwm_polarity polarity)
243 struct pwm_device *pwm;
247 if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
248 !chip->ops->enable || !chip->ops->disable || !chip->npwm)
251 mutex_lock(&pwm_lock);
253 ret = alloc_pwms(chip->base, chip->npwm);
257 chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
265 for (i = 0; i < chip->npwm; i++) {
266 pwm = &chip->pwms[i];
269 pwm->pwm = chip->base + i;
271 pwm->polarity = polarity;
273 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
276 bitmap_set(allocated_pwms, chip->base, chip->npwm);
278 INIT_LIST_HEAD(&chip->list);
279 list_add(&chip->list, &pwm_chips);
283 if (IS_ENABLED(CONFIG_OF))
284 of_pwmchip_add(chip);
286 pwmchip_sysfs_export(chip);
289 mutex_unlock(&pwm_lock);
292 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
295 * pwmchip_add() - register a new PWM chip
296 * @chip: the PWM chip to add
298 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
299 * will be used. The initial polarity for all channels is normal.
301 * Returns: 0 on success or a negative error code on failure.
303 int pwmchip_add(struct pwm_chip *chip)
305 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
307 EXPORT_SYMBOL_GPL(pwmchip_add);
310 * pwmchip_remove() - remove a PWM chip
311 * @chip: the PWM chip to remove
313 * Removes a PWM chip. This function may return busy if the PWM chip provides
314 * a PWM device that is still requested.
316 * Returns: 0 on success or a negative error code on failure.
318 int pwmchip_remove(struct pwm_chip *chip)
323 mutex_lock(&pwm_lock);
325 for (i = 0; i < chip->npwm; i++) {
326 struct pwm_device *pwm = &chip->pwms[i];
328 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
334 list_del_init(&chip->list);
336 if (IS_ENABLED(CONFIG_OF))
337 of_pwmchip_remove(chip);
341 pwmchip_sysfs_unexport(chip);
344 mutex_unlock(&pwm_lock);
347 EXPORT_SYMBOL_GPL(pwmchip_remove);
350 * pwm_request() - request a PWM device
351 * @pwm: global PWM device index
352 * @label: PWM device label
354 * This function is deprecated, use pwm_get() instead.
356 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
359 struct pwm_device *pwm_request(int pwm, const char *label)
361 struct pwm_device *dev;
364 if (pwm < 0 || pwm >= MAX_PWMS)
365 return ERR_PTR(-EINVAL);
367 mutex_lock(&pwm_lock);
369 dev = pwm_to_device(pwm);
371 dev = ERR_PTR(-EPROBE_DEFER);
375 err = pwm_device_request(dev, label);
380 mutex_unlock(&pwm_lock);
384 EXPORT_SYMBOL_GPL(pwm_request);
387 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
389 * @index: per-chip index of the PWM to request
390 * @label: a literal description string of this PWM
392 * Returns: A pointer to the PWM device at the given index of the given PWM
393 * chip. A negative error code is returned if the index is not valid for the
394 * specified PWM chip or if the PWM device cannot be requested.
396 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
400 struct pwm_device *pwm;
403 if (!chip || index >= chip->npwm)
404 return ERR_PTR(-EINVAL);
406 mutex_lock(&pwm_lock);
407 pwm = &chip->pwms[index];
409 err = pwm_device_request(pwm, label);
413 mutex_unlock(&pwm_lock);
416 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
419 * pwm_free() - free a PWM device
422 * This function is deprecated, use pwm_put() instead.
424 void pwm_free(struct pwm_device *pwm)
428 EXPORT_SYMBOL_GPL(pwm_free);
431 * pwm_config() - change a PWM device configuration
433 * @duty_ns: "on" time (in nanoseconds)
434 * @period_ns: duration (in nanoseconds) of one cycle
436 * Returns: 0 on success or a negative error code on failure.
438 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
442 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
445 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
449 pwm->duty_cycle = duty_ns;
450 pwm->period = period_ns;
454 EXPORT_SYMBOL_GPL(pwm_config);
457 * pwm_set_polarity() - configure the polarity of a PWM signal
459 * @polarity: new polarity of the PWM signal
461 * Note that the polarity cannot be configured while the PWM device is
464 * Returns: 0 on success or a negative error code on failure.
466 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
470 if (!pwm || !pwm->chip->ops)
473 if (!pwm->chip->ops->set_polarity)
476 if (pwm_is_enabled(pwm))
479 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
483 pwm->polarity = polarity;
487 EXPORT_SYMBOL_GPL(pwm_set_polarity);
490 * pwm_enable() - start a PWM output toggling
493 * Returns: 0 on success or a negative error code on failure.
495 int pwm_enable(struct pwm_device *pwm)
497 if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
498 return pwm->chip->ops->enable(pwm->chip, pwm);
500 return pwm ? 0 : -EINVAL;
502 EXPORT_SYMBOL_GPL(pwm_enable);
505 * pwm_disable() - stop a PWM output toggling
508 void pwm_disable(struct pwm_device *pwm)
510 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
511 pwm->chip->ops->disable(pwm->chip, pwm);
513 EXPORT_SYMBOL_GPL(pwm_disable);
515 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
517 struct pwm_chip *chip;
519 mutex_lock(&pwm_lock);
521 list_for_each_entry(chip, &pwm_chips, list)
522 if (chip->dev && chip->dev->of_node == np) {
523 mutex_unlock(&pwm_lock);
527 mutex_unlock(&pwm_lock);
529 return ERR_PTR(-EPROBE_DEFER);
533 * of_pwm_get() - request a PWM via the PWM framework
534 * @np: device node to get the PWM from
535 * @con_id: consumer name
537 * Returns the PWM device parsed from the phandle and index specified in the
538 * "pwms" property of a device tree node or a negative error-code on failure.
539 * Values parsed from the device tree are stored in the returned PWM device
542 * If con_id is NULL, the first PWM device listed in the "pwms" property will
543 * be requested. Otherwise the "pwm-names" property is used to do a reverse
544 * lookup of the PWM index. This also means that the "pwm-names" property
545 * becomes mandatory for devices that look up the PWM device via the con_id
548 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
549 * error code on failure.
551 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
553 struct pwm_device *pwm = NULL;
554 struct of_phandle_args args;
560 index = of_property_match_string(np, "pwm-names", con_id);
562 return ERR_PTR(index);
565 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
568 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
572 pc = of_node_to_pwmchip(args.np);
574 pr_debug("%s(): PWM chip not found\n", __func__);
579 if (args.args_count != pc->of_pwm_n_cells) {
580 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
582 pwm = ERR_PTR(-EINVAL);
586 pwm = pc->of_xlate(pc, &args);
591 * If a consumer name was not given, try to look it up from the
592 * "pwm-names" property if it exists. Otherwise use the name of
593 * the user device node.
596 err = of_property_read_string_index(np, "pwm-names", index,
605 of_node_put(args.np);
609 EXPORT_SYMBOL_GPL(of_pwm_get);
612 * pwm_add_table() - register PWM device consumers
613 * @table: array of consumers to register
614 * @num: number of consumers in table
616 void pwm_add_table(struct pwm_lookup *table, size_t num)
618 mutex_lock(&pwm_lookup_lock);
621 list_add_tail(&table->list, &pwm_lookup_list);
625 mutex_unlock(&pwm_lookup_lock);
629 * pwm_remove_table() - unregister PWM device consumers
630 * @table: array of consumers to unregister
631 * @num: number of consumers in table
633 void pwm_remove_table(struct pwm_lookup *table, size_t num)
635 mutex_lock(&pwm_lookup_lock);
638 list_del(&table->list);
642 mutex_unlock(&pwm_lookup_lock);
646 * pwm_get() - look up and request a PWM device
647 * @dev: device for PWM consumer
648 * @con_id: consumer name
650 * Lookup is first attempted using DT. If the device was not instantiated from
651 * a device tree, a PWM chip and a relative index is looked up via a table
652 * supplied by board setup code (see pwm_add_table()).
654 * Once a PWM chip has been found the specified PWM device will be requested
655 * and is ready to be used.
657 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
658 * error code on failure.
660 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
662 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
663 const char *dev_id = dev ? dev_name(dev) : NULL;
664 struct pwm_chip *chip = NULL;
665 unsigned int best = 0;
666 struct pwm_lookup *p, *chosen = NULL;
669 /* look up via DT first */
670 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
671 return of_pwm_get(dev->of_node, con_id);
674 * We look up the provider in the static table typically provided by
675 * board setup code. We first try to lookup the consumer device by
676 * name. If the consumer device was passed in as NULL or if no match
677 * was found, we try to find the consumer by directly looking it up
680 * If a match is found, the provider PWM chip is looked up by name
681 * and a PWM device is requested using the PWM device per-chip index.
683 * The lookup algorithm was shamelessly taken from the clock
686 * We do slightly fuzzy matching here:
687 * An entry with a NULL ID is assumed to be a wildcard.
688 * If an entry has a device ID, it must match
689 * If an entry has a connection ID, it must match
690 * Then we take the most specific entry - with the following order
691 * of precedence: dev+con > dev only > con only.
693 mutex_lock(&pwm_lookup_lock);
695 list_for_each_entry(p, &pwm_lookup_list, list) {
699 if (!dev_id || strcmp(p->dev_id, dev_id))
706 if (!con_id || strcmp(p->con_id, con_id))
725 chip = pwmchip_find_by_name(chosen->provider);
729 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
733 pwm_set_period(pwm, chosen->period);
734 pwm_set_polarity(pwm, chosen->polarity);
737 mutex_unlock(&pwm_lookup_lock);
740 EXPORT_SYMBOL_GPL(pwm_get);
743 * pwm_put() - release a PWM device
746 void pwm_put(struct pwm_device *pwm)
751 mutex_lock(&pwm_lock);
753 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
754 pr_warn("PWM device already freed\n");
758 if (pwm->chip->ops->free)
759 pwm->chip->ops->free(pwm->chip, pwm);
763 module_put(pwm->chip->ops->owner);
765 mutex_unlock(&pwm_lock);
767 EXPORT_SYMBOL_GPL(pwm_put);
769 static void devm_pwm_release(struct device *dev, void *res)
771 pwm_put(*(struct pwm_device **)res);
775 * devm_pwm_get() - resource managed pwm_get()
776 * @dev: device for PWM consumer
777 * @con_id: consumer name
779 * This function performs like pwm_get() but the acquired PWM device will
780 * automatically be released on driver detach.
782 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
783 * error code on failure.
785 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
787 struct pwm_device **ptr, *pwm;
789 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
791 return ERR_PTR(-ENOMEM);
793 pwm = pwm_get(dev, con_id);
796 devres_add(dev, ptr);
803 EXPORT_SYMBOL_GPL(devm_pwm_get);
806 * devm_of_pwm_get() - resource managed of_pwm_get()
807 * @dev: device for PWM consumer
808 * @np: device node to get the PWM from
809 * @con_id: consumer name
811 * This function performs like of_pwm_get() but the acquired PWM device will
812 * automatically be released on driver detach.
814 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
815 * error code on failure.
817 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
820 struct pwm_device **ptr, *pwm;
822 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
824 return ERR_PTR(-ENOMEM);
826 pwm = of_pwm_get(np, con_id);
829 devres_add(dev, ptr);
836 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
838 static int devm_pwm_match(struct device *dev, void *res, void *data)
840 struct pwm_device **p = res;
842 if (WARN_ON(!p || !*p))
849 * devm_pwm_put() - resource managed pwm_put()
850 * @dev: device for PWM consumer
853 * Release a PWM previously allocated using devm_pwm_get(). Calling this
854 * function is usually not needed because devm-allocated resources are
855 * automatically released on driver detach.
857 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
859 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
861 EXPORT_SYMBOL_GPL(devm_pwm_put);
864 * pwm_can_sleep() - report whether PWM access will sleep
867 * Returns: True if accessing the PWM can sleep, false otherwise.
869 bool pwm_can_sleep(struct pwm_device *pwm)
871 return pwm->chip->can_sleep;
873 EXPORT_SYMBOL_GPL(pwm_can_sleep);
875 #ifdef CONFIG_DEBUG_FS
876 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
880 for (i = 0; i < chip->npwm; i++) {
881 struct pwm_device *pwm = &chip->pwms[i];
883 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
885 if (test_bit(PWMF_REQUESTED, &pwm->flags))
886 seq_puts(s, " requested");
888 if (pwm_is_enabled(pwm))
889 seq_puts(s, " enabled");
895 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
897 mutex_lock(&pwm_lock);
900 return seq_list_start(&pwm_chips, *pos);
903 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
907 return seq_list_next(v, &pwm_chips, pos);
910 static void pwm_seq_stop(struct seq_file *s, void *v)
912 mutex_unlock(&pwm_lock);
915 static int pwm_seq_show(struct seq_file *s, void *v)
917 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
919 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
920 chip->dev->bus ? chip->dev->bus->name : "no-bus",
921 dev_name(chip->dev), chip->npwm,
922 (chip->npwm != 1) ? "s" : "");
924 if (chip->ops->dbg_show)
925 chip->ops->dbg_show(chip, s);
927 pwm_dbg_show(chip, s);
932 static const struct seq_operations pwm_seq_ops = {
933 .start = pwm_seq_start,
934 .next = pwm_seq_next,
935 .stop = pwm_seq_stop,
936 .show = pwm_seq_show,
939 static int pwm_seq_open(struct inode *inode, struct file *file)
941 return seq_open(file, &pwm_seq_ops);
944 static const struct file_operations pwm_debugfs_ops = {
945 .owner = THIS_MODULE,
946 .open = pwm_seq_open,
949 .release = seq_release,
952 static int __init pwm_debugfs_init(void)
954 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
959 subsys_initcall(pwm_debugfs_init);
960 #endif /* CONFIG_DEBUG_FS */