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;
272 mutex_init(&pwm->lock);
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->duty_cycle = duty_ns;
453 pwm->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 mutex_lock(&pwm->lock);
481 if (pwm_is_enabled(pwm)) {
486 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
490 pwm->polarity = polarity;
493 mutex_unlock(&pwm->lock);
496 EXPORT_SYMBOL_GPL(pwm_set_polarity);
499 * pwm_enable() - start a PWM output toggling
502 * Returns: 0 on success or a negative error code on failure.
504 int pwm_enable(struct pwm_device *pwm)
511 mutex_lock(&pwm->lock);
513 if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
514 err = pwm->chip->ops->enable(pwm->chip, pwm);
516 clear_bit(PWMF_ENABLED, &pwm->flags);
519 mutex_unlock(&pwm->lock);
523 EXPORT_SYMBOL_GPL(pwm_enable);
526 * pwm_disable() - stop a PWM output toggling
529 void pwm_disable(struct pwm_device *pwm)
531 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
532 pwm->chip->ops->disable(pwm->chip, pwm);
534 EXPORT_SYMBOL_GPL(pwm_disable);
536 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
538 struct pwm_chip *chip;
540 mutex_lock(&pwm_lock);
542 list_for_each_entry(chip, &pwm_chips, list)
543 if (chip->dev && chip->dev->of_node == np) {
544 mutex_unlock(&pwm_lock);
548 mutex_unlock(&pwm_lock);
550 return ERR_PTR(-EPROBE_DEFER);
554 * of_pwm_get() - request a PWM via the PWM framework
555 * @np: device node to get the PWM from
556 * @con_id: consumer name
558 * Returns the PWM device parsed from the phandle and index specified in the
559 * "pwms" property of a device tree node or a negative error-code on failure.
560 * Values parsed from the device tree are stored in the returned PWM device
563 * If con_id is NULL, the first PWM device listed in the "pwms" property will
564 * be requested. Otherwise the "pwm-names" property is used to do a reverse
565 * lookup of the PWM index. This also means that the "pwm-names" property
566 * becomes mandatory for devices that look up the PWM device via the con_id
569 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
570 * error code on failure.
572 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
574 struct pwm_device *pwm = NULL;
575 struct of_phandle_args args;
581 index = of_property_match_string(np, "pwm-names", con_id);
583 return ERR_PTR(index);
586 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
589 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
593 pc = of_node_to_pwmchip(args.np);
595 pr_debug("%s(): PWM chip not found\n", __func__);
600 if (args.args_count != pc->of_pwm_n_cells) {
601 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
603 pwm = ERR_PTR(-EINVAL);
607 pwm = pc->of_xlate(pc, &args);
612 * If a consumer name was not given, try to look it up from the
613 * "pwm-names" property if it exists. Otherwise use the name of
614 * the user device node.
617 err = of_property_read_string_index(np, "pwm-names", index,
626 of_node_put(args.np);
630 EXPORT_SYMBOL_GPL(of_pwm_get);
633 * pwm_add_table() - register PWM device consumers
634 * @table: array of consumers to register
635 * @num: number of consumers in table
637 void pwm_add_table(struct pwm_lookup *table, size_t num)
639 mutex_lock(&pwm_lookup_lock);
642 list_add_tail(&table->list, &pwm_lookup_list);
646 mutex_unlock(&pwm_lookup_lock);
650 * pwm_remove_table() - unregister PWM device consumers
651 * @table: array of consumers to unregister
652 * @num: number of consumers in table
654 void pwm_remove_table(struct pwm_lookup *table, size_t num)
656 mutex_lock(&pwm_lookup_lock);
659 list_del(&table->list);
663 mutex_unlock(&pwm_lookup_lock);
667 * pwm_get() - look up and request a PWM device
668 * @dev: device for PWM consumer
669 * @con_id: consumer name
671 * Lookup is first attempted using DT. If the device was not instantiated from
672 * a device tree, a PWM chip and a relative index is looked up via a table
673 * supplied by board setup code (see pwm_add_table()).
675 * Once a PWM chip has been found the specified PWM device will be requested
676 * and is ready to be used.
678 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
679 * error code on failure.
681 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
683 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
684 const char *dev_id = dev ? dev_name(dev) : NULL;
685 struct pwm_chip *chip = NULL;
686 unsigned int best = 0;
687 struct pwm_lookup *p, *chosen = NULL;
690 /* look up via DT first */
691 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
692 return of_pwm_get(dev->of_node, con_id);
695 * We look up the provider in the static table typically provided by
696 * board setup code. We first try to lookup the consumer device by
697 * name. If the consumer device was passed in as NULL or if no match
698 * was found, we try to find the consumer by directly looking it up
701 * If a match is found, the provider PWM chip is looked up by name
702 * and a PWM device is requested using the PWM device per-chip index.
704 * The lookup algorithm was shamelessly taken from the clock
707 * We do slightly fuzzy matching here:
708 * An entry with a NULL ID is assumed to be a wildcard.
709 * If an entry has a device ID, it must match
710 * If an entry has a connection ID, it must match
711 * Then we take the most specific entry - with the following order
712 * of precedence: dev+con > dev only > con only.
714 mutex_lock(&pwm_lookup_lock);
716 list_for_each_entry(p, &pwm_lookup_list, list) {
720 if (!dev_id || strcmp(p->dev_id, dev_id))
727 if (!con_id || strcmp(p->con_id, con_id))
744 pwm = ERR_PTR(-ENODEV);
748 chip = pwmchip_find_by_name(chosen->provider);
752 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
756 pwm_set_period(pwm, chosen->period);
757 pwm_set_polarity(pwm, chosen->polarity);
760 mutex_unlock(&pwm_lookup_lock);
763 EXPORT_SYMBOL_GPL(pwm_get);
766 * pwm_put() - release a PWM device
769 void pwm_put(struct pwm_device *pwm)
774 mutex_lock(&pwm_lock);
776 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
777 pr_warn("PWM device already freed\n");
781 if (pwm->chip->ops->free)
782 pwm->chip->ops->free(pwm->chip, pwm);
786 module_put(pwm->chip->ops->owner);
788 mutex_unlock(&pwm_lock);
790 EXPORT_SYMBOL_GPL(pwm_put);
792 static void devm_pwm_release(struct device *dev, void *res)
794 pwm_put(*(struct pwm_device **)res);
798 * devm_pwm_get() - resource managed pwm_get()
799 * @dev: device for PWM consumer
800 * @con_id: consumer name
802 * This function performs like pwm_get() but the acquired PWM device will
803 * automatically be released on driver detach.
805 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
806 * error code on failure.
808 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
810 struct pwm_device **ptr, *pwm;
812 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
814 return ERR_PTR(-ENOMEM);
816 pwm = pwm_get(dev, con_id);
819 devres_add(dev, ptr);
826 EXPORT_SYMBOL_GPL(devm_pwm_get);
829 * devm_of_pwm_get() - resource managed of_pwm_get()
830 * @dev: device for PWM consumer
831 * @np: device node to get the PWM from
832 * @con_id: consumer name
834 * This function performs like of_pwm_get() but the acquired PWM device will
835 * automatically be released on driver detach.
837 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
838 * error code on failure.
840 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
843 struct pwm_device **ptr, *pwm;
845 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
847 return ERR_PTR(-ENOMEM);
849 pwm = of_pwm_get(np, con_id);
852 devres_add(dev, ptr);
859 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
861 static int devm_pwm_match(struct device *dev, void *res, void *data)
863 struct pwm_device **p = res;
865 if (WARN_ON(!p || !*p))
872 * devm_pwm_put() - resource managed pwm_put()
873 * @dev: device for PWM consumer
876 * Release a PWM previously allocated using devm_pwm_get(). Calling this
877 * function is usually not needed because devm-allocated resources are
878 * automatically released on driver detach.
880 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
882 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
884 EXPORT_SYMBOL_GPL(devm_pwm_put);
887 * pwm_can_sleep() - report whether PWM access will sleep
890 * Returns: True if accessing the PWM can sleep, false otherwise.
892 bool pwm_can_sleep(struct pwm_device *pwm)
896 EXPORT_SYMBOL_GPL(pwm_can_sleep);
898 #ifdef CONFIG_DEBUG_FS
899 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
903 for (i = 0; i < chip->npwm; i++) {
904 struct pwm_device *pwm = &chip->pwms[i];
906 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
908 if (test_bit(PWMF_REQUESTED, &pwm->flags))
909 seq_puts(s, " requested");
911 if (pwm_is_enabled(pwm))
912 seq_puts(s, " enabled");
918 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
920 mutex_lock(&pwm_lock);
923 return seq_list_start(&pwm_chips, *pos);
926 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
930 return seq_list_next(v, &pwm_chips, pos);
933 static void pwm_seq_stop(struct seq_file *s, void *v)
935 mutex_unlock(&pwm_lock);
938 static int pwm_seq_show(struct seq_file *s, void *v)
940 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
942 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
943 chip->dev->bus ? chip->dev->bus->name : "no-bus",
944 dev_name(chip->dev), chip->npwm,
945 (chip->npwm != 1) ? "s" : "");
947 if (chip->ops->dbg_show)
948 chip->ops->dbg_show(chip, s);
950 pwm_dbg_show(chip, s);
955 static const struct seq_operations pwm_seq_ops = {
956 .start = pwm_seq_start,
957 .next = pwm_seq_next,
958 .stop = pwm_seq_stop,
959 .show = pwm_seq_show,
962 static int pwm_seq_open(struct inode *inode, struct file *file)
964 return seq_open(file, &pwm_seq_ops);
967 static const struct file_operations pwm_debugfs_ops = {
968 .owner = THIS_MODULE,
969 .open = pwm_seq_open,
972 .release = seq_release,
975 static int __init pwm_debugfs_init(void)
977 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
982 subsys_initcall(pwm_debugfs_init);
983 #endif /* CONFIG_DEBUG_FS */