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);
133 * FIXME: This should be removed once all PWM users properly make use
134 * of struct pwm_args to initialize the PWM device. As long as this is
135 * here, the PWM state and hardware state can get out of sync.
143 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
145 struct pwm_device *pwm;
147 if (pc->of_pwm_n_cells < 3)
148 return ERR_PTR(-EINVAL);
150 if (args->args[0] >= pc->npwm)
151 return ERR_PTR(-EINVAL);
153 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
157 pwm->args.period = args->args[1];
159 if (args->args[2] & PWM_POLARITY_INVERTED)
160 pwm->args.polarity = PWM_POLARITY_INVERSED;
162 pwm->args.polarity = PWM_POLARITY_NORMAL;
166 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
168 static struct pwm_device *
169 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
171 struct pwm_device *pwm;
173 if (pc->of_pwm_n_cells < 2)
174 return ERR_PTR(-EINVAL);
176 if (args->args[0] >= pc->npwm)
177 return ERR_PTR(-EINVAL);
179 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
183 pwm->args.period = args->args[1];
188 static void of_pwmchip_add(struct pwm_chip *chip)
190 if (!chip->dev || !chip->dev->of_node)
193 if (!chip->of_xlate) {
194 chip->of_xlate = of_pwm_simple_xlate;
195 chip->of_pwm_n_cells = 2;
198 of_node_get(chip->dev->of_node);
201 static void of_pwmchip_remove(struct pwm_chip *chip)
204 of_node_put(chip->dev->of_node);
208 * pwm_set_chip_data() - set private chip data for a PWM
210 * @data: pointer to chip-specific data
212 * Returns: 0 on success or a negative error code on failure.
214 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
219 pwm->chip_data = data;
223 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
226 * pwm_get_chip_data() - get private chip data for a PWM
229 * Returns: A pointer to the chip-private data for the PWM device.
231 void *pwm_get_chip_data(struct pwm_device *pwm)
233 return pwm ? pwm->chip_data : NULL;
235 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
238 * pwmchip_add_with_polarity() - register a new PWM chip
239 * @chip: the PWM chip to add
240 * @polarity: initial polarity of PWM channels
242 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
243 * will be used. The initial polarity for all channels is specified by the
244 * @polarity parameter.
246 * Returns: 0 on success or a negative error code on failure.
248 int pwmchip_add_with_polarity(struct pwm_chip *chip,
249 enum pwm_polarity polarity)
251 struct pwm_device *pwm;
255 if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
256 !chip->ops->enable || !chip->ops->disable || !chip->npwm)
259 mutex_lock(&pwm_lock);
261 ret = alloc_pwms(chip->base, chip->npwm);
265 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
273 for (i = 0; i < chip->npwm; i++) {
274 pwm = &chip->pwms[i];
277 pwm->pwm = chip->base + i;
279 pwm->polarity = polarity;
280 mutex_init(&pwm->lock);
282 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
285 bitmap_set(allocated_pwms, chip->base, chip->npwm);
287 INIT_LIST_HEAD(&chip->list);
288 list_add(&chip->list, &pwm_chips);
292 if (IS_ENABLED(CONFIG_OF))
293 of_pwmchip_add(chip);
295 pwmchip_sysfs_export(chip);
298 mutex_unlock(&pwm_lock);
301 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
304 * pwmchip_add() - register a new PWM chip
305 * @chip: the PWM chip to add
307 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
308 * will be used. The initial polarity for all channels is normal.
310 * Returns: 0 on success or a negative error code on failure.
312 int pwmchip_add(struct pwm_chip *chip)
314 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
316 EXPORT_SYMBOL_GPL(pwmchip_add);
319 * pwmchip_remove() - remove a PWM chip
320 * @chip: the PWM chip to remove
322 * Removes a PWM chip. This function may return busy if the PWM chip provides
323 * a PWM device that is still requested.
325 * Returns: 0 on success or a negative error code on failure.
327 int pwmchip_remove(struct pwm_chip *chip)
332 pwmchip_sysfs_unexport_children(chip);
334 mutex_lock(&pwm_lock);
336 for (i = 0; i < chip->npwm; i++) {
337 struct pwm_device *pwm = &chip->pwms[i];
339 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
345 list_del_init(&chip->list);
347 if (IS_ENABLED(CONFIG_OF))
348 of_pwmchip_remove(chip);
352 pwmchip_sysfs_unexport(chip);
355 mutex_unlock(&pwm_lock);
358 EXPORT_SYMBOL_GPL(pwmchip_remove);
361 * pwm_request() - request a PWM device
362 * @pwm: global PWM device index
363 * @label: PWM device label
365 * This function is deprecated, use pwm_get() instead.
367 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
370 struct pwm_device *pwm_request(int pwm, const char *label)
372 struct pwm_device *dev;
375 if (pwm < 0 || pwm >= MAX_PWMS)
376 return ERR_PTR(-EINVAL);
378 mutex_lock(&pwm_lock);
380 dev = pwm_to_device(pwm);
382 dev = ERR_PTR(-EPROBE_DEFER);
386 err = pwm_device_request(dev, label);
391 mutex_unlock(&pwm_lock);
395 EXPORT_SYMBOL_GPL(pwm_request);
398 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
400 * @index: per-chip index of the PWM to request
401 * @label: a literal description string of this PWM
403 * Returns: A pointer to the PWM device at the given index of the given PWM
404 * chip. A negative error code is returned if the index is not valid for the
405 * specified PWM chip or if the PWM device cannot be requested.
407 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
411 struct pwm_device *pwm;
414 if (!chip || index >= chip->npwm)
415 return ERR_PTR(-EINVAL);
417 mutex_lock(&pwm_lock);
418 pwm = &chip->pwms[index];
420 err = pwm_device_request(pwm, label);
424 mutex_unlock(&pwm_lock);
427 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
430 * pwm_free() - free a PWM device
433 * This function is deprecated, use pwm_put() instead.
435 void pwm_free(struct pwm_device *pwm)
439 EXPORT_SYMBOL_GPL(pwm_free);
442 * pwm_config() - change a PWM device configuration
444 * @duty_ns: "on" time (in nanoseconds)
445 * @period_ns: duration (in nanoseconds) of one cycle
447 * Returns: 0 on success or a negative error code on failure.
449 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
453 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
456 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
460 pwm->duty_cycle = duty_ns;
461 pwm->period = period_ns;
465 EXPORT_SYMBOL_GPL(pwm_config);
468 * pwm_set_polarity() - configure the polarity of a PWM signal
470 * @polarity: new polarity of the PWM signal
472 * Note that the polarity cannot be configured while the PWM device is
475 * Returns: 0 on success or a negative error code on failure.
477 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
481 if (!pwm || !pwm->chip->ops)
484 if (!pwm->chip->ops->set_polarity)
487 mutex_lock(&pwm->lock);
489 if (pwm_is_enabled(pwm)) {
494 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
498 pwm->polarity = polarity;
501 mutex_unlock(&pwm->lock);
504 EXPORT_SYMBOL_GPL(pwm_set_polarity);
507 * pwm_enable() - start a PWM output toggling
510 * Returns: 0 on success or a negative error code on failure.
512 int pwm_enable(struct pwm_device *pwm)
519 mutex_lock(&pwm->lock);
521 if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
522 err = pwm->chip->ops->enable(pwm->chip, pwm);
524 clear_bit(PWMF_ENABLED, &pwm->flags);
527 mutex_unlock(&pwm->lock);
531 EXPORT_SYMBOL_GPL(pwm_enable);
534 * pwm_disable() - stop a PWM output toggling
537 void pwm_disable(struct pwm_device *pwm)
539 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
540 pwm->chip->ops->disable(pwm->chip, pwm);
542 EXPORT_SYMBOL_GPL(pwm_disable);
544 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
546 struct pwm_chip *chip;
548 mutex_lock(&pwm_lock);
550 list_for_each_entry(chip, &pwm_chips, list)
551 if (chip->dev && chip->dev->of_node == np) {
552 mutex_unlock(&pwm_lock);
556 mutex_unlock(&pwm_lock);
558 return ERR_PTR(-EPROBE_DEFER);
562 * of_pwm_get() - request a PWM via the PWM framework
563 * @np: device node to get the PWM from
564 * @con_id: consumer name
566 * Returns the PWM device parsed from the phandle and index specified in the
567 * "pwms" property of a device tree node or a negative error-code on failure.
568 * Values parsed from the device tree are stored in the returned PWM device
571 * If con_id is NULL, the first PWM device listed in the "pwms" property will
572 * be requested. Otherwise the "pwm-names" property is used to do a reverse
573 * lookup of the PWM index. This also means that the "pwm-names" property
574 * becomes mandatory for devices that look up the PWM device via the con_id
577 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
578 * error code on failure.
580 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
582 struct pwm_device *pwm = NULL;
583 struct of_phandle_args args;
589 index = of_property_match_string(np, "pwm-names", con_id);
591 return ERR_PTR(index);
594 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
597 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
601 pc = of_node_to_pwmchip(args.np);
603 pr_debug("%s(): PWM chip not found\n", __func__);
608 if (args.args_count != pc->of_pwm_n_cells) {
609 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
611 pwm = ERR_PTR(-EINVAL);
615 pwm = pc->of_xlate(pc, &args);
620 * If a consumer name was not given, try to look it up from the
621 * "pwm-names" property if it exists. Otherwise use the name of
622 * the user device node.
625 err = of_property_read_string_index(np, "pwm-names", index,
634 of_node_put(args.np);
638 EXPORT_SYMBOL_GPL(of_pwm_get);
641 * pwm_add_table() - register PWM device consumers
642 * @table: array of consumers to register
643 * @num: number of consumers in table
645 void pwm_add_table(struct pwm_lookup *table, size_t num)
647 mutex_lock(&pwm_lookup_lock);
650 list_add_tail(&table->list, &pwm_lookup_list);
654 mutex_unlock(&pwm_lookup_lock);
658 * pwm_remove_table() - unregister PWM device consumers
659 * @table: array of consumers to unregister
660 * @num: number of consumers in table
662 void pwm_remove_table(struct pwm_lookup *table, size_t num)
664 mutex_lock(&pwm_lookup_lock);
667 list_del(&table->list);
671 mutex_unlock(&pwm_lookup_lock);
675 * pwm_get() - look up and request a PWM device
676 * @dev: device for PWM consumer
677 * @con_id: consumer name
679 * Lookup is first attempted using DT. If the device was not instantiated from
680 * a device tree, a PWM chip and a relative index is looked up via a table
681 * supplied by board setup code (see pwm_add_table()).
683 * Once a PWM chip has been found the specified PWM device will be requested
684 * and is ready to be used.
686 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
687 * error code on failure.
689 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
691 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
692 const char *dev_id = dev ? dev_name(dev) : NULL;
693 struct pwm_chip *chip = NULL;
694 unsigned int best = 0;
695 struct pwm_lookup *p, *chosen = NULL;
698 /* look up via DT first */
699 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
700 return of_pwm_get(dev->of_node, con_id);
703 * We look up the provider in the static table typically provided by
704 * board setup code. We first try to lookup the consumer device by
705 * name. If the consumer device was passed in as NULL or if no match
706 * was found, we try to find the consumer by directly looking it up
709 * If a match is found, the provider PWM chip is looked up by name
710 * and a PWM device is requested using the PWM device per-chip index.
712 * The lookup algorithm was shamelessly taken from the clock
715 * We do slightly fuzzy matching here:
716 * An entry with a NULL ID is assumed to be a wildcard.
717 * If an entry has a device ID, it must match
718 * If an entry has a connection ID, it must match
719 * Then we take the most specific entry - with the following order
720 * of precedence: dev+con > dev only > con only.
722 mutex_lock(&pwm_lookup_lock);
724 list_for_each_entry(p, &pwm_lookup_list, list) {
728 if (!dev_id || strcmp(p->dev_id, dev_id))
735 if (!con_id || strcmp(p->con_id, con_id))
752 pwm = ERR_PTR(-ENODEV);
756 chip = pwmchip_find_by_name(chosen->provider);
760 pwm->args.period = chosen->period;
761 pwm->args.polarity = chosen->polarity;
763 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
768 mutex_unlock(&pwm_lookup_lock);
771 EXPORT_SYMBOL_GPL(pwm_get);
774 * pwm_put() - release a PWM device
777 void pwm_put(struct pwm_device *pwm)
782 mutex_lock(&pwm_lock);
784 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
785 pr_warn("PWM device already freed\n");
789 if (pwm->chip->ops->free)
790 pwm->chip->ops->free(pwm->chip, pwm);
794 module_put(pwm->chip->ops->owner);
796 mutex_unlock(&pwm_lock);
798 EXPORT_SYMBOL_GPL(pwm_put);
800 static void devm_pwm_release(struct device *dev, void *res)
802 pwm_put(*(struct pwm_device **)res);
806 * devm_pwm_get() - resource managed pwm_get()
807 * @dev: device for PWM consumer
808 * @con_id: consumer name
810 * This function performs like pwm_get() but the acquired PWM device will
811 * automatically be released on driver detach.
813 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
814 * error code on failure.
816 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
818 struct pwm_device **ptr, *pwm;
820 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
822 return ERR_PTR(-ENOMEM);
824 pwm = pwm_get(dev, con_id);
827 devres_add(dev, ptr);
834 EXPORT_SYMBOL_GPL(devm_pwm_get);
837 * devm_of_pwm_get() - resource managed of_pwm_get()
838 * @dev: device for PWM consumer
839 * @np: device node to get the PWM from
840 * @con_id: consumer name
842 * This function performs like of_pwm_get() but the acquired PWM device will
843 * automatically be released on driver detach.
845 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
846 * error code on failure.
848 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
851 struct pwm_device **ptr, *pwm;
853 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
855 return ERR_PTR(-ENOMEM);
857 pwm = of_pwm_get(np, con_id);
860 devres_add(dev, ptr);
867 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
869 static int devm_pwm_match(struct device *dev, void *res, void *data)
871 struct pwm_device **p = res;
873 if (WARN_ON(!p || !*p))
880 * devm_pwm_put() - resource managed pwm_put()
881 * @dev: device for PWM consumer
884 * Release a PWM previously allocated using devm_pwm_get(). Calling this
885 * function is usually not needed because devm-allocated resources are
886 * automatically released on driver detach.
888 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
890 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
892 EXPORT_SYMBOL_GPL(devm_pwm_put);
895 * pwm_can_sleep() - report whether PWM access will sleep
898 * Returns: True if accessing the PWM can sleep, false otherwise.
900 bool pwm_can_sleep(struct pwm_device *pwm)
904 EXPORT_SYMBOL_GPL(pwm_can_sleep);
906 #ifdef CONFIG_DEBUG_FS
907 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
911 for (i = 0; i < chip->npwm; i++) {
912 struct pwm_device *pwm = &chip->pwms[i];
914 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
916 if (test_bit(PWMF_REQUESTED, &pwm->flags))
917 seq_puts(s, " requested");
919 if (pwm_is_enabled(pwm))
920 seq_puts(s, " enabled");
926 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
928 mutex_lock(&pwm_lock);
931 return seq_list_start(&pwm_chips, *pos);
934 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
938 return seq_list_next(v, &pwm_chips, pos);
941 static void pwm_seq_stop(struct seq_file *s, void *v)
943 mutex_unlock(&pwm_lock);
946 static int pwm_seq_show(struct seq_file *s, void *v)
948 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
950 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
951 chip->dev->bus ? chip->dev->bus->name : "no-bus",
952 dev_name(chip->dev), chip->npwm,
953 (chip->npwm != 1) ? "s" : "");
955 if (chip->ops->dbg_show)
956 chip->ops->dbg_show(chip, s);
958 pwm_dbg_show(chip, s);
963 static const struct seq_operations pwm_seq_ops = {
964 .start = pwm_seq_start,
965 .next = pwm_seq_next,
966 .stop = pwm_seq_stop,
967 .show = pwm_seq_show,
970 static int pwm_seq_open(struct inode *inode, struct file *file)
972 return seq_open(file, &pwm_seq_ops);
975 static const struct file_operations pwm_debugfs_ops = {
976 .owner = THIS_MODULE,
977 .open = pwm_seq_open,
980 .release = seq_release,
983 static int __init pwm_debugfs_init(void)
985 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
990 subsys_initcall(pwm_debugfs_init);
991 #endif /* CONFIG_DEBUG_FS */