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);
134 static struct pwm_device *of_pwm_xlate(struct pwm_chip *pc,
135 const struct of_phandle_args *args)
137 struct pwm_device *pwm;
139 if (pc->of_pwm_n_cells < 2)
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 (pc->of_pwm_n_cells < 3)
154 if (args->args[2] & PWM_POLARITY_INVERTED)
155 pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
157 pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
163 __deprecated of_pwm_xlate_with_flags(struct pwm_chip *pc,
164 const struct of_phandle_args *args)
166 return of_pwm_xlate(pc, args);
168 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
170 static void of_pwmchip_add(struct pwm_chip *chip)
172 if (!chip->dev || !chip->dev->of_node)
175 if (!chip->of_xlate) {
176 chip->of_xlate = of_pwm_xlate;
177 chip->of_pwm_n_cells = 2;
180 of_node_get(chip->dev->of_node);
183 static void of_pwmchip_remove(struct pwm_chip *chip)
185 if (chip->dev && chip->dev->of_node)
186 of_node_put(chip->dev->of_node);
190 * pwm_set_chip_data() - set private chip data for a PWM
192 * @data: pointer to chip-specific data
194 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
199 pwm->chip_data = data;
203 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
206 * pwm_get_chip_data() - get private chip data for a PWM
209 void *pwm_get_chip_data(struct pwm_device *pwm)
211 return pwm ? pwm->chip_data : NULL;
213 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
216 * pwmchip_add() - register a new PWM chip
217 * @chip: the PWM chip to add
219 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
222 int pwmchip_add(struct pwm_chip *chip)
224 struct pwm_device *pwm;
228 if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
229 !chip->ops->enable || !chip->ops->disable)
232 mutex_lock(&pwm_lock);
234 ret = alloc_pwms(chip->base, chip->npwm);
238 chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
246 for (i = 0; i < chip->npwm; i++) {
247 pwm = &chip->pwms[i];
250 pwm->pwm = chip->base + i;
253 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
256 bitmap_set(allocated_pwms, chip->base, chip->npwm);
258 INIT_LIST_HEAD(&chip->list);
259 list_add(&chip->list, &pwm_chips);
263 if (IS_ENABLED(CONFIG_OF))
264 of_pwmchip_add(chip);
266 pwmchip_sysfs_export(chip);
269 mutex_unlock(&pwm_lock);
272 EXPORT_SYMBOL_GPL(pwmchip_add);
275 * pwmchip_remove() - remove a PWM chip
276 * @chip: the PWM chip to remove
278 * Removes a PWM chip. This function may return busy if the PWM chip provides
279 * a PWM device that is still requested.
281 int pwmchip_remove(struct pwm_chip *chip)
286 mutex_lock(&pwm_lock);
288 for (i = 0; i < chip->npwm; i++) {
289 struct pwm_device *pwm = &chip->pwms[i];
291 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
297 list_del_init(&chip->list);
299 if (IS_ENABLED(CONFIG_OF))
300 of_pwmchip_remove(chip);
304 pwmchip_sysfs_unexport(chip);
307 mutex_unlock(&pwm_lock);
310 EXPORT_SYMBOL_GPL(pwmchip_remove);
313 * pwm_request() - request a PWM device
314 * @pwm_id: global PWM device index
315 * @label: PWM device label
317 * This function is deprecated, use pwm_get() instead.
319 struct pwm_device *pwm_request(int pwm, const char *label)
321 struct pwm_device *dev;
324 if (pwm < 0 || pwm >= MAX_PWMS)
325 return ERR_PTR(-EINVAL);
327 mutex_lock(&pwm_lock);
329 dev = pwm_to_device(pwm);
331 dev = ERR_PTR(-EPROBE_DEFER);
335 err = pwm_device_request(dev, label);
340 mutex_unlock(&pwm_lock);
344 EXPORT_SYMBOL_GPL(pwm_request);
347 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
349 * @index: per-chip index of the PWM to request
350 * @label: a literal description string of this PWM
352 * Returns the PWM at the given index of the given PWM chip. A negative error
353 * code is returned if the index is not valid for the specified PWM chip or
354 * if the PWM device cannot be requested.
356 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
360 struct pwm_device *pwm;
363 if (!chip || index >= chip->npwm)
364 return ERR_PTR(-EINVAL);
366 mutex_lock(&pwm_lock);
367 pwm = &chip->pwms[index];
369 err = pwm_device_request(pwm, label);
373 mutex_unlock(&pwm_lock);
376 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
379 * pwm_free() - free a PWM device
382 * This function is deprecated, use pwm_put() instead.
384 void pwm_free(struct pwm_device *pwm)
388 EXPORT_SYMBOL_GPL(pwm_free);
391 * pwm_config() - change a PWM device configuration
393 * @duty_ns: "on" time (in nanoseconds)
394 * @period_ns: duration (in nanoseconds) of one cycle
396 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
400 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
403 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
407 pwm->duty_cycle = duty_ns;
408 pwm->period = period_ns;
412 EXPORT_SYMBOL_GPL(pwm_config);
415 * pwm_set_polarity() - configure the polarity of a PWM signal
417 * @polarity: new polarity of the PWM signal
419 * Note that the polarity cannot be configured while the PWM device is enabled
421 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
425 if (!pwm || !pwm->chip->ops)
428 if (!pwm->chip->ops->set_polarity)
431 if (test_bit(PWMF_ENABLED, &pwm->flags))
434 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
438 pwm->polarity = polarity;
442 EXPORT_SYMBOL_GPL(pwm_set_polarity);
445 * pwm_enable() - start a PWM output toggling
448 int pwm_enable(struct pwm_device *pwm)
450 if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
451 return pwm->chip->ops->enable(pwm->chip, pwm);
453 return pwm ? 0 : -EINVAL;
455 EXPORT_SYMBOL_GPL(pwm_enable);
458 * pwm_disable() - stop a PWM output toggling
461 void pwm_disable(struct pwm_device *pwm)
463 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
464 pwm->chip->ops->disable(pwm->chip, pwm);
466 EXPORT_SYMBOL_GPL(pwm_disable);
468 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
470 struct pwm_chip *chip;
472 mutex_lock(&pwm_lock);
474 list_for_each_entry(chip, &pwm_chips, list)
475 if (chip->dev && chip->dev->of_node == np) {
476 mutex_unlock(&pwm_lock);
480 mutex_unlock(&pwm_lock);
482 return ERR_PTR(-EPROBE_DEFER);
486 * of_pwm_get() - request a PWM via the PWM framework
487 * @np: device node to get the PWM from
488 * @con_id: consumer name
490 * Returns the PWM device parsed from the phandle and index specified in the
491 * "pwms" property of a device tree node or a negative error-code on failure.
492 * Values parsed from the device tree are stored in the returned PWM device
495 * If con_id is NULL, the first PWM device listed in the "pwms" property will
496 * be requested. Otherwise the "pwm-names" property is used to do a reverse
497 * lookup of the PWM index. This also means that the "pwm-names" property
498 * becomes mandatory for devices that look up the PWM device via the con_id
501 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
503 struct pwm_device *pwm = NULL;
504 struct of_phandle_args args;
510 index = of_property_match_string(np, "pwm-names", con_id);
512 return ERR_PTR(index);
515 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
518 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
522 pc = of_node_to_pwmchip(args.np);
524 pr_err("%s(): PWM chip not found\n", __func__);
529 pwm = pc->of_xlate(pc, &args);
534 * If a consumer name was not given, try to look it up from the
535 * "pwm-names" property if it exists. Otherwise use the name of
536 * the user device node.
539 err = of_property_read_string_index(np, "pwm-names", index,
548 of_node_put(args.np);
552 EXPORT_SYMBOL_GPL(of_pwm_get);
555 * pwm_add_table() - register PWM device consumers
556 * @table: array of consumers to register
557 * @num: number of consumers in table
559 void __init pwm_add_table(struct pwm_lookup *table, size_t num)
561 mutex_lock(&pwm_lookup_lock);
564 list_add_tail(&table->list, &pwm_lookup_list);
568 mutex_unlock(&pwm_lookup_lock);
572 * pwm_get() - look up and request a PWM device
573 * @dev: device for PWM consumer
574 * @con_id: consumer name
576 * Lookup is first attempted using DT. If the device was not instantiated from
577 * a device tree, a PWM chip and a relative index is looked up via a table
578 * supplied by board setup code (see pwm_add_table()).
580 * Once a PWM chip has been found the specified PWM device will be requested
581 * and is ready to be used.
583 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
585 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
586 const char *dev_id = dev ? dev_name(dev) : NULL;
587 struct pwm_chip *chip = NULL;
588 unsigned int index = 0;
589 unsigned int best = 0;
590 struct pwm_lookup *p;
593 /* look up via DT first */
594 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
595 return of_pwm_get(dev->of_node, con_id);
598 * We look up the provider in the static table typically provided by
599 * board setup code. We first try to lookup the consumer device by
600 * name. If the consumer device was passed in as NULL or if no match
601 * was found, we try to find the consumer by directly looking it up
604 * If a match is found, the provider PWM chip is looked up by name
605 * and a PWM device is requested using the PWM device per-chip index.
607 * The lookup algorithm was shamelessly taken from the clock
610 * We do slightly fuzzy matching here:
611 * An entry with a NULL ID is assumed to be a wildcard.
612 * If an entry has a device ID, it must match
613 * If an entry has a connection ID, it must match
614 * Then we take the most specific entry - with the following order
615 * of precedence: dev+con > dev only > con only.
617 mutex_lock(&pwm_lookup_lock);
619 list_for_each_entry(p, &pwm_lookup_list, list) {
623 if (!dev_id || strcmp(p->dev_id, dev_id))
630 if (!con_id || strcmp(p->con_id, con_id))
637 chip = pwmchip_find_by_name(p->provider);
648 pwm = pwm_request_from_chip(chip, index, con_id ?: dev_id);
650 mutex_unlock(&pwm_lookup_lock);
654 EXPORT_SYMBOL_GPL(pwm_get);
657 * pwm_put() - release a PWM device
660 void pwm_put(struct pwm_device *pwm)
665 mutex_lock(&pwm_lock);
667 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
668 pr_warn("PWM device already freed\n");
672 if (pwm->chip->ops->free)
673 pwm->chip->ops->free(pwm->chip, pwm);
677 module_put(pwm->chip->ops->owner);
679 mutex_unlock(&pwm_lock);
681 EXPORT_SYMBOL_GPL(pwm_put);
683 static void devm_pwm_release(struct device *dev, void *res)
685 pwm_put(*(struct pwm_device **)res);
689 * devm_pwm_get() - resource managed pwm_get()
690 * @dev: device for PWM consumer
691 * @con_id: consumer name
693 * This function performs like pwm_get() but the acquired PWM device will
694 * automatically be released on driver detach.
696 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
698 struct pwm_device **ptr, *pwm;
700 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
702 return ERR_PTR(-ENOMEM);
704 pwm = pwm_get(dev, con_id);
707 devres_add(dev, ptr);
714 EXPORT_SYMBOL_GPL(devm_pwm_get);
717 * devm_of_pwm_get() - resource managed of_pwm_get()
718 * @dev: device for PWM consumer
719 * @np: device node to get the PWM from
720 * @con_id: consumer name
722 * This function performs like of_pwm_get() but the acquired PWM device will
723 * automatically be released on driver detach.
725 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
728 struct pwm_device **ptr, *pwm;
730 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
732 return ERR_PTR(-ENOMEM);
734 pwm = of_pwm_get(np, con_id);
737 devres_add(dev, ptr);
744 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
746 static int devm_pwm_match(struct device *dev, void *res, void *data)
748 struct pwm_device **p = res;
750 if (WARN_ON(!p || !*p))
757 * devm_pwm_put() - resource managed pwm_put()
758 * @dev: device for PWM consumer
761 * Release a PWM previously allocated using devm_pwm_get(). Calling this
762 * function is usually not needed because devm-allocated resources are
763 * automatically released on driver detach.
765 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
767 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
769 EXPORT_SYMBOL_GPL(devm_pwm_put);
772 * pwm_can_sleep() - report whether PWM access will sleep
775 * It returns true if accessing the PWM can sleep, false otherwise.
777 bool pwm_can_sleep(struct pwm_device *pwm)
779 return pwm->chip->can_sleep;
781 EXPORT_SYMBOL_GPL(pwm_can_sleep);
783 #ifdef CONFIG_DEBUG_FS
784 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
788 for (i = 0; i < chip->npwm; i++) {
789 struct pwm_device *pwm = &chip->pwms[i];
791 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
793 if (test_bit(PWMF_REQUESTED, &pwm->flags))
794 seq_printf(s, " requested");
796 if (test_bit(PWMF_ENABLED, &pwm->flags))
797 seq_printf(s, " enabled");
803 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
805 mutex_lock(&pwm_lock);
808 return seq_list_start(&pwm_chips, *pos);
811 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
815 return seq_list_next(v, &pwm_chips, pos);
818 static void pwm_seq_stop(struct seq_file *s, void *v)
820 mutex_unlock(&pwm_lock);
823 static int pwm_seq_show(struct seq_file *s, void *v)
825 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
827 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
828 chip->dev->bus ? chip->dev->bus->name : "no-bus",
829 dev_name(chip->dev), chip->npwm,
830 (chip->npwm != 1) ? "s" : "");
832 if (chip->ops->dbg_show)
833 chip->ops->dbg_show(chip, s);
835 pwm_dbg_show(chip, s);
840 static const struct seq_operations pwm_seq_ops = {
841 .start = pwm_seq_start,
842 .next = pwm_seq_next,
843 .stop = pwm_seq_stop,
844 .show = pwm_seq_show,
847 static int pwm_seq_open(struct inode *inode, struct file *file)
849 return seq_open(file, &pwm_seq_ops);
852 static const struct file_operations pwm_debugfs_ops = {
853 .owner = THIS_MODULE,
854 .open = pwm_seq_open,
857 .release = seq_release,
860 static int __init pwm_debugfs_init(void)
862 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
868 subsys_initcall(pwm_debugfs_init);
869 #endif /* CONFIG_DEBUG_FS */