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 if (chip->ops->get_state)
275 chip->ops->get_state(chip, pwm, &pwm->state);
277 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
280 bitmap_set(allocated_pwms, chip->base, chip->npwm);
282 INIT_LIST_HEAD(&chip->list);
283 list_add(&chip->list, &pwm_chips);
287 if (IS_ENABLED(CONFIG_OF))
288 of_pwmchip_add(chip);
290 pwmchip_sysfs_export(chip);
293 mutex_unlock(&pwm_lock);
296 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
299 * pwmchip_add() - register a new PWM chip
300 * @chip: the PWM chip to add
302 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
303 * will be used. The initial polarity for all channels is normal.
305 * Returns: 0 on success or a negative error code on failure.
307 int pwmchip_add(struct pwm_chip *chip)
309 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
311 EXPORT_SYMBOL_GPL(pwmchip_add);
314 * pwmchip_remove() - remove a PWM chip
315 * @chip: the PWM chip to remove
317 * Removes a PWM chip. This function may return busy if the PWM chip provides
318 * a PWM device that is still requested.
320 * Returns: 0 on success or a negative error code on failure.
322 int pwmchip_remove(struct pwm_chip *chip)
327 pwmchip_sysfs_unexport_children(chip);
329 mutex_lock(&pwm_lock);
331 for (i = 0; i < chip->npwm; i++) {
332 struct pwm_device *pwm = &chip->pwms[i];
334 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
340 list_del_init(&chip->list);
342 if (IS_ENABLED(CONFIG_OF))
343 of_pwmchip_remove(chip);
347 pwmchip_sysfs_unexport(chip);
350 mutex_unlock(&pwm_lock);
353 EXPORT_SYMBOL_GPL(pwmchip_remove);
356 * pwm_request() - request a PWM device
357 * @pwm: global PWM device index
358 * @label: PWM device label
360 * This function is deprecated, use pwm_get() instead.
362 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
365 struct pwm_device *pwm_request(int pwm, const char *label)
367 struct pwm_device *dev;
370 if (pwm < 0 || pwm >= MAX_PWMS)
371 return ERR_PTR(-EINVAL);
373 mutex_lock(&pwm_lock);
375 dev = pwm_to_device(pwm);
377 dev = ERR_PTR(-EPROBE_DEFER);
381 err = pwm_device_request(dev, label);
386 mutex_unlock(&pwm_lock);
390 EXPORT_SYMBOL_GPL(pwm_request);
393 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
395 * @index: per-chip index of the PWM to request
396 * @label: a literal description string of this PWM
398 * Returns: A pointer to the PWM device at the given index of the given PWM
399 * chip. A negative error code is returned if the index is not valid for the
400 * specified PWM chip or if the PWM device cannot be requested.
402 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
406 struct pwm_device *pwm;
409 if (!chip || index >= chip->npwm)
410 return ERR_PTR(-EINVAL);
412 mutex_lock(&pwm_lock);
413 pwm = &chip->pwms[index];
415 err = pwm_device_request(pwm, label);
419 mutex_unlock(&pwm_lock);
422 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
425 * pwm_free() - free a PWM device
428 * This function is deprecated, use pwm_put() instead.
430 void pwm_free(struct pwm_device *pwm)
434 EXPORT_SYMBOL_GPL(pwm_free);
437 * pwm_config() - change a PWM device configuration
439 * @duty_ns: "on" time (in nanoseconds)
440 * @period_ns: duration (in nanoseconds) of one cycle
442 * Returns: 0 on success or a negative error code on failure.
444 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
448 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
451 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
455 pwm->state.duty_cycle = duty_ns;
456 pwm->state.period = period_ns;
460 EXPORT_SYMBOL_GPL(pwm_config);
463 * pwm_set_polarity() - configure the polarity of a PWM signal
465 * @polarity: new polarity of the PWM signal
467 * Note that the polarity cannot be configured while the PWM device is
470 * Returns: 0 on success or a negative error code on failure.
472 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
476 if (!pwm || !pwm->chip->ops)
479 if (!pwm->chip->ops->set_polarity)
482 if (pwm_is_enabled(pwm))
485 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
489 pwm->state.polarity = polarity;
493 EXPORT_SYMBOL_GPL(pwm_set_polarity);
496 * pwm_enable() - start a PWM output toggling
499 * Returns: 0 on success or a negative error code on failure.
501 int pwm_enable(struct pwm_device *pwm)
508 if (!pwm_is_enabled(pwm)) {
509 err = pwm->chip->ops->enable(pwm->chip, pwm);
511 pwm->state.enabled = true;
516 EXPORT_SYMBOL_GPL(pwm_enable);
519 * pwm_disable() - stop a PWM output toggling
522 void pwm_disable(struct pwm_device *pwm)
527 if (pwm_is_enabled(pwm)) {
528 pwm->chip->ops->disable(pwm->chip, pwm);
529 pwm->state.enabled = false;
532 EXPORT_SYMBOL_GPL(pwm_disable);
534 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
536 struct pwm_chip *chip;
538 mutex_lock(&pwm_lock);
540 list_for_each_entry(chip, &pwm_chips, list)
541 if (chip->dev && chip->dev->of_node == np) {
542 mutex_unlock(&pwm_lock);
546 mutex_unlock(&pwm_lock);
548 return ERR_PTR(-EPROBE_DEFER);
552 * of_pwm_get() - request a PWM via the PWM framework
553 * @np: device node to get the PWM from
554 * @con_id: consumer name
556 * Returns the PWM device parsed from the phandle and index specified in the
557 * "pwms" property of a device tree node or a negative error-code on failure.
558 * Values parsed from the device tree are stored in the returned PWM device
561 * If con_id is NULL, the first PWM device listed in the "pwms" property will
562 * be requested. Otherwise the "pwm-names" property is used to do a reverse
563 * lookup of the PWM index. This also means that the "pwm-names" property
564 * becomes mandatory for devices that look up the PWM device via the con_id
567 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
568 * error code on failure.
570 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
572 struct pwm_device *pwm = NULL;
573 struct of_phandle_args args;
579 index = of_property_match_string(np, "pwm-names", con_id);
581 return ERR_PTR(index);
584 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
587 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
591 pc = of_node_to_pwmchip(args.np);
593 pr_debug("%s(): PWM chip not found\n", __func__);
598 if (args.args_count != pc->of_pwm_n_cells) {
599 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
601 pwm = ERR_PTR(-EINVAL);
605 pwm = pc->of_xlate(pc, &args);
610 * If a consumer name was not given, try to look it up from the
611 * "pwm-names" property if it exists. Otherwise use the name of
612 * the user device node.
615 err = of_property_read_string_index(np, "pwm-names", index,
624 of_node_put(args.np);
628 EXPORT_SYMBOL_GPL(of_pwm_get);
631 * pwm_add_table() - register PWM device consumers
632 * @table: array of consumers to register
633 * @num: number of consumers in table
635 void pwm_add_table(struct pwm_lookup *table, size_t num)
637 mutex_lock(&pwm_lookup_lock);
640 list_add_tail(&table->list, &pwm_lookup_list);
644 mutex_unlock(&pwm_lookup_lock);
648 * pwm_remove_table() - unregister PWM device consumers
649 * @table: array of consumers to unregister
650 * @num: number of consumers in table
652 void pwm_remove_table(struct pwm_lookup *table, size_t num)
654 mutex_lock(&pwm_lookup_lock);
657 list_del(&table->list);
661 mutex_unlock(&pwm_lookup_lock);
665 * pwm_get() - look up and request a PWM device
666 * @dev: device for PWM consumer
667 * @con_id: consumer name
669 * Lookup is first attempted using DT. If the device was not instantiated from
670 * a device tree, a PWM chip and a relative index is looked up via a table
671 * supplied by board setup code (see pwm_add_table()).
673 * Once a PWM chip has been found the specified PWM device will be requested
674 * and is ready to be used.
676 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
677 * error code on failure.
679 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
681 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
682 const char *dev_id = dev ? dev_name(dev) : NULL;
683 struct pwm_chip *chip = NULL;
684 unsigned int best = 0;
685 struct pwm_lookup *p, *chosen = NULL;
688 /* look up via DT first */
689 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
690 return of_pwm_get(dev->of_node, con_id);
693 * We look up the provider in the static table typically provided by
694 * board setup code. We first try to lookup the consumer device by
695 * name. If the consumer device was passed in as NULL or if no match
696 * was found, we try to find the consumer by directly looking it up
699 * If a match is found, the provider PWM chip is looked up by name
700 * and a PWM device is requested using the PWM device per-chip index.
702 * The lookup algorithm was shamelessly taken from the clock
705 * We do slightly fuzzy matching here:
706 * An entry with a NULL ID is assumed to be a wildcard.
707 * If an entry has a device ID, it must match
708 * If an entry has a connection ID, it must match
709 * Then we take the most specific entry - with the following order
710 * of precedence: dev+con > dev only > con only.
712 mutex_lock(&pwm_lookup_lock);
714 list_for_each_entry(p, &pwm_lookup_list, list) {
718 if (!dev_id || strcmp(p->dev_id, dev_id))
725 if (!con_id || strcmp(p->con_id, con_id))
742 pwm = ERR_PTR(-ENODEV);
746 chip = pwmchip_find_by_name(chosen->provider);
750 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
754 pwm->args.period = chosen->period;
755 pwm->args.polarity = chosen->polarity;
758 mutex_unlock(&pwm_lookup_lock);
761 EXPORT_SYMBOL_GPL(pwm_get);
764 * pwm_put() - release a PWM device
767 void pwm_put(struct pwm_device *pwm)
772 mutex_lock(&pwm_lock);
774 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
775 pr_warn("PWM device already freed\n");
779 if (pwm->chip->ops->free)
780 pwm->chip->ops->free(pwm->chip, pwm);
784 module_put(pwm->chip->ops->owner);
786 mutex_unlock(&pwm_lock);
788 EXPORT_SYMBOL_GPL(pwm_put);
790 static void devm_pwm_release(struct device *dev, void *res)
792 pwm_put(*(struct pwm_device **)res);
796 * devm_pwm_get() - resource managed pwm_get()
797 * @dev: device for PWM consumer
798 * @con_id: consumer name
800 * This function performs like pwm_get() but the acquired PWM device will
801 * automatically be released on driver detach.
803 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
804 * error code on failure.
806 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
808 struct pwm_device **ptr, *pwm;
810 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
812 return ERR_PTR(-ENOMEM);
814 pwm = pwm_get(dev, con_id);
817 devres_add(dev, ptr);
824 EXPORT_SYMBOL_GPL(devm_pwm_get);
827 * devm_of_pwm_get() - resource managed of_pwm_get()
828 * @dev: device for PWM consumer
829 * @np: device node to get the PWM from
830 * @con_id: consumer name
832 * This function performs like of_pwm_get() but the acquired PWM device will
833 * automatically be released on driver detach.
835 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
836 * error code on failure.
838 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
841 struct pwm_device **ptr, *pwm;
843 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
845 return ERR_PTR(-ENOMEM);
847 pwm = of_pwm_get(np, con_id);
850 devres_add(dev, ptr);
857 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
859 static int devm_pwm_match(struct device *dev, void *res, void *data)
861 struct pwm_device **p = res;
863 if (WARN_ON(!p || !*p))
870 * devm_pwm_put() - resource managed pwm_put()
871 * @dev: device for PWM consumer
874 * Release a PWM previously allocated using devm_pwm_get(). Calling this
875 * function is usually not needed because devm-allocated resources are
876 * automatically released on driver detach.
878 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
880 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
882 EXPORT_SYMBOL_GPL(devm_pwm_put);
885 * pwm_can_sleep() - report whether PWM access will sleep
888 * Returns: True if accessing the PWM can sleep, false otherwise.
890 bool pwm_can_sleep(struct pwm_device *pwm)
894 EXPORT_SYMBOL_GPL(pwm_can_sleep);
896 #ifdef CONFIG_DEBUG_FS
897 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
901 for (i = 0; i < chip->npwm; i++) {
902 struct pwm_device *pwm = &chip->pwms[i];
904 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
906 if (test_bit(PWMF_REQUESTED, &pwm->flags))
907 seq_puts(s, " requested");
909 if (pwm_is_enabled(pwm))
910 seq_puts(s, " enabled");
916 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
918 mutex_lock(&pwm_lock);
921 return seq_list_start(&pwm_chips, *pos);
924 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
928 return seq_list_next(v, &pwm_chips, pos);
931 static void pwm_seq_stop(struct seq_file *s, void *v)
933 mutex_unlock(&pwm_lock);
936 static int pwm_seq_show(struct seq_file *s, void *v)
938 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
940 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
941 chip->dev->bus ? chip->dev->bus->name : "no-bus",
942 dev_name(chip->dev), chip->npwm,
943 (chip->npwm != 1) ? "s" : "");
945 if (chip->ops->dbg_show)
946 chip->ops->dbg_show(chip, s);
948 pwm_dbg_show(chip, s);
953 static const struct seq_operations pwm_seq_ops = {
954 .start = pwm_seq_start,
955 .next = pwm_seq_next,
956 .stop = pwm_seq_stop,
957 .show = pwm_seq_show,
960 static int pwm_seq_open(struct inode *inode, struct file *file)
962 return seq_open(file, &pwm_seq_ops);
965 static const struct file_operations pwm_debugfs_ops = {
966 .owner = THIS_MODULE,
967 .open = pwm_seq_open,
970 .release = seq_release,
973 static int __init pwm_debugfs_init(void)
975 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
980 subsys_initcall(pwm_debugfs_init);
981 #endif /* CONFIG_DEBUG_FS */