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 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
209 pwm->chip_data = data;
213 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
216 * pwm_get_chip_data() - get private chip data for a PWM
219 void *pwm_get_chip_data(struct pwm_device *pwm)
221 return pwm ? pwm->chip_data : NULL;
223 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
226 * pwmchip_add_with_polarity() - register a new PWM chip
227 * @chip: the PWM chip to add
228 * @polarity: initial polarity of PWM channels
230 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
231 * will be used. The initial polarity for all channels is specified by the
232 * @polarity parameter.
234 int pwmchip_add_with_polarity(struct pwm_chip *chip,
235 enum pwm_polarity polarity)
237 struct pwm_device *pwm;
241 if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
242 !chip->ops->enable || !chip->ops->disable || !chip->npwm)
245 mutex_lock(&pwm_lock);
247 ret = alloc_pwms(chip->base, chip->npwm);
251 chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
259 for (i = 0; i < chip->npwm; i++) {
260 pwm = &chip->pwms[i];
263 pwm->pwm = chip->base + i;
265 pwm->polarity = polarity;
267 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
270 bitmap_set(allocated_pwms, chip->base, chip->npwm);
272 INIT_LIST_HEAD(&chip->list);
273 list_add(&chip->list, &pwm_chips);
277 if (IS_ENABLED(CONFIG_OF))
278 of_pwmchip_add(chip);
280 pwmchip_sysfs_export(chip);
283 mutex_unlock(&pwm_lock);
286 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
289 * pwmchip_add() - register a new PWM chip
290 * @chip: the PWM chip to add
292 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
293 * will be used. The initial polarity for all channels is normal.
295 int pwmchip_add(struct pwm_chip *chip)
297 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
299 EXPORT_SYMBOL_GPL(pwmchip_add);
302 * pwmchip_remove() - remove a PWM chip
303 * @chip: the PWM chip to remove
305 * Removes a PWM chip. This function may return busy if the PWM chip provides
306 * a PWM device that is still requested.
308 int pwmchip_remove(struct pwm_chip *chip)
313 mutex_lock(&pwm_lock);
315 for (i = 0; i < chip->npwm; i++) {
316 struct pwm_device *pwm = &chip->pwms[i];
318 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
324 list_del_init(&chip->list);
326 if (IS_ENABLED(CONFIG_OF))
327 of_pwmchip_remove(chip);
331 pwmchip_sysfs_unexport(chip);
334 mutex_unlock(&pwm_lock);
337 EXPORT_SYMBOL_GPL(pwmchip_remove);
340 * pwm_request() - request a PWM device
341 * @pwm_id: global PWM device index
342 * @label: PWM device label
344 * This function is deprecated, use pwm_get() instead.
346 struct pwm_device *pwm_request(int pwm, const char *label)
348 struct pwm_device *dev;
351 if (pwm < 0 || pwm >= MAX_PWMS)
352 return ERR_PTR(-EINVAL);
354 mutex_lock(&pwm_lock);
356 dev = pwm_to_device(pwm);
358 dev = ERR_PTR(-EPROBE_DEFER);
362 err = pwm_device_request(dev, label);
367 mutex_unlock(&pwm_lock);
371 EXPORT_SYMBOL_GPL(pwm_request);
374 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
376 * @index: per-chip index of the PWM to request
377 * @label: a literal description string of this PWM
379 * Returns the PWM at the given index of the given PWM chip. A negative error
380 * code is returned if the index is not valid for the specified PWM chip or
381 * if the PWM device cannot be requested.
383 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
387 struct pwm_device *pwm;
390 if (!chip || index >= chip->npwm)
391 return ERR_PTR(-EINVAL);
393 mutex_lock(&pwm_lock);
394 pwm = &chip->pwms[index];
396 err = pwm_device_request(pwm, label);
400 mutex_unlock(&pwm_lock);
403 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
406 * pwm_free() - free a PWM device
409 * This function is deprecated, use pwm_put() instead.
411 void pwm_free(struct pwm_device *pwm)
415 EXPORT_SYMBOL_GPL(pwm_free);
418 * pwm_config() - change a PWM device configuration
420 * @duty_ns: "on" time (in nanoseconds)
421 * @period_ns: duration (in nanoseconds) of one cycle
423 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
427 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
430 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
434 pwm->duty_cycle = duty_ns;
435 pwm->period = period_ns;
439 EXPORT_SYMBOL_GPL(pwm_config);
442 * pwm_set_polarity() - configure the polarity of a PWM signal
444 * @polarity: new polarity of the PWM signal
446 * Note that the polarity cannot be configured while the PWM device is enabled
448 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
452 if (!pwm || !pwm->chip->ops)
455 if (!pwm->chip->ops->set_polarity)
458 if (test_bit(PWMF_ENABLED, &pwm->flags))
461 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
465 pwm->polarity = polarity;
469 EXPORT_SYMBOL_GPL(pwm_set_polarity);
472 * pwm_enable() - start a PWM output toggling
475 int pwm_enable(struct pwm_device *pwm)
477 if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
478 return pwm->chip->ops->enable(pwm->chip, pwm);
480 return pwm ? 0 : -EINVAL;
482 EXPORT_SYMBOL_GPL(pwm_enable);
485 * pwm_disable() - stop a PWM output toggling
488 void pwm_disable(struct pwm_device *pwm)
490 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
491 pwm->chip->ops->disable(pwm->chip, pwm);
493 EXPORT_SYMBOL_GPL(pwm_disable);
495 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
497 struct pwm_chip *chip;
499 mutex_lock(&pwm_lock);
501 list_for_each_entry(chip, &pwm_chips, list)
502 if (chip->dev && chip->dev->of_node == np) {
503 mutex_unlock(&pwm_lock);
507 mutex_unlock(&pwm_lock);
509 return ERR_PTR(-EPROBE_DEFER);
513 * of_pwm_get() - request a PWM via the PWM framework
514 * @np: device node to get the PWM from
515 * @con_id: consumer name
517 * Returns the PWM device parsed from the phandle and index specified in the
518 * "pwms" property of a device tree node or a negative error-code on failure.
519 * Values parsed from the device tree are stored in the returned PWM device
522 * If con_id is NULL, the first PWM device listed in the "pwms" property will
523 * be requested. Otherwise the "pwm-names" property is used to do a reverse
524 * lookup of the PWM index. This also means that the "pwm-names" property
525 * becomes mandatory for devices that look up the PWM device via the con_id
528 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
530 struct pwm_device *pwm = NULL;
531 struct of_phandle_args args;
537 index = of_property_match_string(np, "pwm-names", con_id);
539 return ERR_PTR(index);
542 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
545 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
549 pc = of_node_to_pwmchip(args.np);
551 pr_debug("%s(): PWM chip not found\n", __func__);
556 if (args.args_count != pc->of_pwm_n_cells) {
557 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
559 pwm = ERR_PTR(-EINVAL);
563 pwm = pc->of_xlate(pc, &args);
568 * If a consumer name was not given, try to look it up from the
569 * "pwm-names" property if it exists. Otherwise use the name of
570 * the user device node.
573 err = of_property_read_string_index(np, "pwm-names", index,
582 of_node_put(args.np);
586 EXPORT_SYMBOL_GPL(of_pwm_get);
589 * pwm_add_table() - register PWM device consumers
590 * @table: array of consumers to register
591 * @num: number of consumers in table
593 void pwm_add_table(struct pwm_lookup *table, size_t num)
595 mutex_lock(&pwm_lookup_lock);
598 list_add_tail(&table->list, &pwm_lookup_list);
602 mutex_unlock(&pwm_lookup_lock);
606 * pwm_remove_table() - unregister PWM device consumers
607 * @table: array of consumers to unregister
608 * @num: number of consumers in table
610 void pwm_remove_table(struct pwm_lookup *table, size_t num)
612 mutex_lock(&pwm_lookup_lock);
615 list_del(&table->list);
619 mutex_unlock(&pwm_lookup_lock);
623 * pwm_get() - look up and request a PWM device
624 * @dev: device for PWM consumer
625 * @con_id: consumer name
627 * Lookup is first attempted using DT. If the device was not instantiated from
628 * a device tree, a PWM chip and a relative index is looked up via a table
629 * supplied by board setup code (see pwm_add_table()).
631 * Once a PWM chip has been found the specified PWM device will be requested
632 * and is ready to be used.
634 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
636 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
637 const char *dev_id = dev ? dev_name(dev) : NULL;
638 struct pwm_chip *chip = NULL;
639 unsigned int best = 0;
640 struct pwm_lookup *p, *chosen = NULL;
643 /* look up via DT first */
644 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
645 return of_pwm_get(dev->of_node, con_id);
648 * We look up the provider in the static table typically provided by
649 * board setup code. We first try to lookup the consumer device by
650 * name. If the consumer device was passed in as NULL or if no match
651 * was found, we try to find the consumer by directly looking it up
654 * If a match is found, the provider PWM chip is looked up by name
655 * and a PWM device is requested using the PWM device per-chip index.
657 * The lookup algorithm was shamelessly taken from the clock
660 * We do slightly fuzzy matching here:
661 * An entry with a NULL ID is assumed to be a wildcard.
662 * If an entry has a device ID, it must match
663 * If an entry has a connection ID, it must match
664 * Then we take the most specific entry - with the following order
665 * of precedence: dev+con > dev only > con only.
667 mutex_lock(&pwm_lookup_lock);
669 list_for_each_entry(p, &pwm_lookup_list, list) {
673 if (!dev_id || strcmp(p->dev_id, dev_id))
680 if (!con_id || strcmp(p->con_id, con_id))
699 chip = pwmchip_find_by_name(chosen->provider);
703 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
707 pwm_set_period(pwm, chosen->period);
708 pwm_set_polarity(pwm, chosen->polarity);
711 mutex_unlock(&pwm_lookup_lock);
714 EXPORT_SYMBOL_GPL(pwm_get);
717 * pwm_put() - release a PWM device
720 void pwm_put(struct pwm_device *pwm)
725 mutex_lock(&pwm_lock);
727 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
728 pr_warn("PWM device already freed\n");
732 if (pwm->chip->ops->free)
733 pwm->chip->ops->free(pwm->chip, pwm);
737 module_put(pwm->chip->ops->owner);
739 mutex_unlock(&pwm_lock);
741 EXPORT_SYMBOL_GPL(pwm_put);
743 static void devm_pwm_release(struct device *dev, void *res)
745 pwm_put(*(struct pwm_device **)res);
749 * devm_pwm_get() - resource managed pwm_get()
750 * @dev: device for PWM consumer
751 * @con_id: consumer name
753 * This function performs like pwm_get() but the acquired PWM device will
754 * automatically be released on driver detach.
756 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
758 struct pwm_device **ptr, *pwm;
760 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
762 return ERR_PTR(-ENOMEM);
764 pwm = pwm_get(dev, con_id);
767 devres_add(dev, ptr);
774 EXPORT_SYMBOL_GPL(devm_pwm_get);
777 * devm_of_pwm_get() - resource managed of_pwm_get()
778 * @dev: device for PWM consumer
779 * @np: device node to get the PWM from
780 * @con_id: consumer name
782 * This function performs like of_pwm_get() but the acquired PWM device will
783 * automatically be released on driver detach.
785 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
788 struct pwm_device **ptr, *pwm;
790 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
792 return ERR_PTR(-ENOMEM);
794 pwm = of_pwm_get(np, con_id);
797 devres_add(dev, ptr);
804 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
806 static int devm_pwm_match(struct device *dev, void *res, void *data)
808 struct pwm_device **p = res;
810 if (WARN_ON(!p || !*p))
817 * devm_pwm_put() - resource managed pwm_put()
818 * @dev: device for PWM consumer
821 * Release a PWM previously allocated using devm_pwm_get(). Calling this
822 * function is usually not needed because devm-allocated resources are
823 * automatically released on driver detach.
825 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
827 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
829 EXPORT_SYMBOL_GPL(devm_pwm_put);
832 * pwm_can_sleep() - report whether PWM access will sleep
835 * It returns true if accessing the PWM can sleep, false otherwise.
837 bool pwm_can_sleep(struct pwm_device *pwm)
839 return pwm->chip->can_sleep;
841 EXPORT_SYMBOL_GPL(pwm_can_sleep);
843 #ifdef CONFIG_DEBUG_FS
844 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
848 for (i = 0; i < chip->npwm; i++) {
849 struct pwm_device *pwm = &chip->pwms[i];
851 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
853 if (test_bit(PWMF_REQUESTED, &pwm->flags))
854 seq_puts(s, " requested");
856 if (test_bit(PWMF_ENABLED, &pwm->flags))
857 seq_puts(s, " enabled");
863 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
865 mutex_lock(&pwm_lock);
868 return seq_list_start(&pwm_chips, *pos);
871 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
875 return seq_list_next(v, &pwm_chips, pos);
878 static void pwm_seq_stop(struct seq_file *s, void *v)
880 mutex_unlock(&pwm_lock);
883 static int pwm_seq_show(struct seq_file *s, void *v)
885 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
887 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
888 chip->dev->bus ? chip->dev->bus->name : "no-bus",
889 dev_name(chip->dev), chip->npwm,
890 (chip->npwm != 1) ? "s" : "");
892 if (chip->ops->dbg_show)
893 chip->ops->dbg_show(chip, s);
895 pwm_dbg_show(chip, s);
900 static const struct seq_operations pwm_seq_ops = {
901 .start = pwm_seq_start,
902 .next = pwm_seq_next,
903 .stop = pwm_seq_stop,
904 .show = pwm_seq_show,
907 static int pwm_seq_open(struct inode *inode, struct file *file)
909 return seq_open(file, &pwm_seq_ops);
912 static const struct file_operations pwm_debugfs_ops = {
913 .owner = THIS_MODULE,
914 .open = pwm_seq_open,
917 .release = seq_release,
920 static int __init pwm_debugfs_init(void)
922 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
928 subsys_initcall(pwm_debugfs_init);
929 #endif /* CONFIG_DEBUG_FS */