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 /* check, whether the driver supports a third cell for flags */
140 if (pc->of_pwm_n_cells < 3)
141 return ERR_PTR(-EINVAL);
143 /* flags in the third cell are optional */
144 if (args->args_count < 2)
145 return ERR_PTR(-EINVAL);
147 if (args->args[0] >= pc->npwm)
148 return ERR_PTR(-EINVAL);
150 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
154 pwm_set_period(pwm, args->args[1]);
156 if (args->args_count > 2) {
157 if (args->args[2] & PWM_POLARITY_INVERTED)
158 pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
160 pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
165 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
167 static struct pwm_device *
168 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
170 struct pwm_device *pwm;
172 /* sanity check driver support */
173 if (pc->of_pwm_n_cells < 2)
174 return ERR_PTR(-EINVAL);
176 /* all cells are required */
177 if (args->args_count != pc->of_pwm_n_cells)
178 return ERR_PTR(-EINVAL);
180 if (args->args[0] >= pc->npwm)
181 return ERR_PTR(-EINVAL);
183 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
187 pwm_set_period(pwm, args->args[1]);
192 static void of_pwmchip_add(struct pwm_chip *chip)
194 if (!chip->dev || !chip->dev->of_node)
197 if (!chip->of_xlate) {
198 chip->of_xlate = of_pwm_simple_xlate;
199 chip->of_pwm_n_cells = 2;
202 of_node_get(chip->dev->of_node);
205 static void of_pwmchip_remove(struct pwm_chip *chip)
208 of_node_put(chip->dev->of_node);
212 * pwm_set_chip_data() - set private chip data for a PWM
214 * @data: pointer to chip-specific data
216 * Returns: 0 on success or a negative error code on failure.
218 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
223 pwm->chip_data = data;
227 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
230 * pwm_get_chip_data() - get private chip data for a PWM
233 * Returns: A pointer to the chip-private data for the PWM device.
235 void *pwm_get_chip_data(struct pwm_device *pwm)
237 return pwm ? pwm->chip_data : NULL;
239 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
242 * pwmchip_add_with_polarity() - register a new PWM chip
243 * @chip: the PWM chip to add
244 * @polarity: initial polarity of PWM channels
246 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
247 * will be used. The initial polarity for all channels is specified by the
248 * @polarity parameter.
250 * Returns: 0 on success or a negative error code on failure.
252 int pwmchip_add_with_polarity(struct pwm_chip *chip,
253 enum pwm_polarity polarity)
255 struct pwm_device *pwm;
259 if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
260 !chip->ops->enable || !chip->ops->disable || !chip->npwm)
263 mutex_lock(&pwm_lock);
265 ret = alloc_pwms(chip->base, chip->npwm);
269 chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
277 for (i = 0; i < chip->npwm; i++) {
278 pwm = &chip->pwms[i];
281 pwm->pwm = chip->base + i;
283 pwm->polarity = polarity;
285 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
288 bitmap_set(allocated_pwms, chip->base, chip->npwm);
290 INIT_LIST_HEAD(&chip->list);
291 list_add(&chip->list, &pwm_chips);
295 if (IS_ENABLED(CONFIG_OF))
296 of_pwmchip_add(chip);
298 pwmchip_sysfs_export(chip);
301 mutex_unlock(&pwm_lock);
304 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
307 * pwmchip_add() - register a new PWM chip
308 * @chip: the PWM chip to add
310 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
311 * will be used. The initial polarity for all channels is normal.
313 * Returns: 0 on success or a negative error code on failure.
315 int pwmchip_add(struct pwm_chip *chip)
317 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
319 EXPORT_SYMBOL_GPL(pwmchip_add);
322 * pwmchip_remove() - remove a PWM chip
323 * @chip: the PWM chip to remove
325 * Removes a PWM chip. This function may return busy if the PWM chip provides
326 * a PWM device that is still requested.
328 * Returns: 0 on success or a negative error code on failure.
330 int pwmchip_remove(struct pwm_chip *chip)
335 mutex_lock(&pwm_lock);
337 for (i = 0; i < chip->npwm; i++) {
338 struct pwm_device *pwm = &chip->pwms[i];
340 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
346 list_del_init(&chip->list);
348 if (IS_ENABLED(CONFIG_OF))
349 of_pwmchip_remove(chip);
353 pwmchip_sysfs_unexport(chip);
356 mutex_unlock(&pwm_lock);
359 EXPORT_SYMBOL_GPL(pwmchip_remove);
362 * pwm_request() - request a PWM device
363 * @pwm: global PWM device index
364 * @label: PWM device label
366 * This function is deprecated, use pwm_get() instead.
368 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
371 struct pwm_device *pwm_request(int pwm, const char *label)
373 struct pwm_device *dev;
376 if (pwm < 0 || pwm >= MAX_PWMS)
377 return ERR_PTR(-EINVAL);
379 mutex_lock(&pwm_lock);
381 dev = pwm_to_device(pwm);
383 dev = ERR_PTR(-EPROBE_DEFER);
387 err = pwm_device_request(dev, label);
392 mutex_unlock(&pwm_lock);
396 EXPORT_SYMBOL_GPL(pwm_request);
399 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
401 * @index: per-chip index of the PWM to request
402 * @label: a literal description string of this PWM
404 * Returns: A pointer to the PWM device at the given index of the given PWM
405 * chip. A negative error code is returned if the index is not valid for the
406 * specified PWM chip or if the PWM device cannot be requested.
408 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
412 struct pwm_device *pwm;
415 if (!chip || index >= chip->npwm)
416 return ERR_PTR(-EINVAL);
418 mutex_lock(&pwm_lock);
419 pwm = &chip->pwms[index];
421 err = pwm_device_request(pwm, label);
425 mutex_unlock(&pwm_lock);
428 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
431 * pwm_free() - free a PWM device
434 * This function is deprecated, use pwm_put() instead.
436 void pwm_free(struct pwm_device *pwm)
440 EXPORT_SYMBOL_GPL(pwm_free);
443 * pwm_config() - change a PWM device configuration
445 * @duty_ns: "on" time (in nanoseconds)
446 * @period_ns: duration (in nanoseconds) of one cycle
448 * Returns: 0 on success or a negative error code on failure.
450 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
454 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
457 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
461 pwm->duty_cycle = duty_ns;
462 pwm->period = period_ns;
466 EXPORT_SYMBOL_GPL(pwm_config);
469 * pwm_set_polarity() - configure the polarity of a PWM signal
471 * @polarity: new polarity of the PWM signal
473 * Note that the polarity cannot be configured while the PWM device is
476 * Returns: 0 on success or a negative error code on failure.
478 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
482 if (!pwm || !pwm->chip->ops)
485 if (!pwm->chip->ops->set_polarity)
488 if (pwm_is_enabled(pwm))
491 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
495 pwm->polarity = polarity;
499 EXPORT_SYMBOL_GPL(pwm_set_polarity);
502 * pwm_enable() - start a PWM output toggling
505 * Returns: 0 on success or a negative error code on failure.
507 int pwm_enable(struct pwm_device *pwm)
509 if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
510 return pwm->chip->ops->enable(pwm->chip, pwm);
512 return pwm ? 0 : -EINVAL;
514 EXPORT_SYMBOL_GPL(pwm_enable);
517 * pwm_disable() - stop a PWM output toggling
520 void pwm_disable(struct pwm_device *pwm)
522 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
523 pwm->chip->ops->disable(pwm->chip, pwm);
525 EXPORT_SYMBOL_GPL(pwm_disable);
527 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
529 struct pwm_chip *chip;
531 mutex_lock(&pwm_lock);
533 list_for_each_entry(chip, &pwm_chips, list)
534 if (chip->dev && chip->dev->of_node == np) {
535 mutex_unlock(&pwm_lock);
539 mutex_unlock(&pwm_lock);
541 return ERR_PTR(-EPROBE_DEFER);
545 * of_pwm_get() - request a PWM via the PWM framework
546 * @np: device node to get the PWM from
547 * @con_id: consumer name
549 * Returns the PWM device parsed from the phandle and index specified in the
550 * "pwms" property of a device tree node or a negative error-code on failure.
551 * Values parsed from the device tree are stored in the returned PWM device
554 * If con_id is NULL, the first PWM device listed in the "pwms" property will
555 * be requested. Otherwise the "pwm-names" property is used to do a reverse
556 * lookup of the PWM index. This also means that the "pwm-names" property
557 * becomes mandatory for devices that look up the PWM device via the con_id
560 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
561 * error code on failure.
563 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
565 struct pwm_device *pwm = NULL;
566 struct of_phandle_args args;
572 index = of_property_match_string(np, "pwm-names", con_id);
574 return ERR_PTR(index);
577 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
580 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
584 pc = of_node_to_pwmchip(args.np);
586 pr_debug("%s(): PWM chip not found\n", __func__);
591 pwm = pc->of_xlate(pc, &args);
596 * If a consumer name was not given, try to look it up from the
597 * "pwm-names" property if it exists. Otherwise use the name of
598 * the user device node.
601 err = of_property_read_string_index(np, "pwm-names", index,
610 of_node_put(args.np);
614 EXPORT_SYMBOL_GPL(of_pwm_get);
617 * pwm_add_table() - register PWM device consumers
618 * @table: array of consumers to register
619 * @num: number of consumers in table
621 void pwm_add_table(struct pwm_lookup *table, size_t num)
623 mutex_lock(&pwm_lookup_lock);
626 list_add_tail(&table->list, &pwm_lookup_list);
630 mutex_unlock(&pwm_lookup_lock);
634 * pwm_remove_table() - unregister PWM device consumers
635 * @table: array of consumers to unregister
636 * @num: number of consumers in table
638 void pwm_remove_table(struct pwm_lookup *table, size_t num)
640 mutex_lock(&pwm_lookup_lock);
643 list_del(&table->list);
647 mutex_unlock(&pwm_lookup_lock);
651 * pwm_get() - look up and request a PWM device
652 * @dev: device for PWM consumer
653 * @con_id: consumer name
655 * Lookup is first attempted using DT. If the device was not instantiated from
656 * a device tree, a PWM chip and a relative index is looked up via a table
657 * supplied by board setup code (see pwm_add_table()).
659 * Once a PWM chip has been found the specified PWM device will be requested
660 * and is ready to be used.
662 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
663 * error code on failure.
665 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
667 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
668 const char *dev_id = dev ? dev_name(dev) : NULL;
669 struct pwm_chip *chip = NULL;
670 unsigned int best = 0;
671 struct pwm_lookup *p, *chosen = NULL;
674 /* look up via DT first */
675 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
676 return of_pwm_get(dev->of_node, con_id);
679 * We look up the provider in the static table typically provided by
680 * board setup code. We first try to lookup the consumer device by
681 * name. If the consumer device was passed in as NULL or if no match
682 * was found, we try to find the consumer by directly looking it up
685 * If a match is found, the provider PWM chip is looked up by name
686 * and a PWM device is requested using the PWM device per-chip index.
688 * The lookup algorithm was shamelessly taken from the clock
691 * We do slightly fuzzy matching here:
692 * An entry with a NULL ID is assumed to be a wildcard.
693 * If an entry has a device ID, it must match
694 * If an entry has a connection ID, it must match
695 * Then we take the most specific entry - with the following order
696 * of precedence: dev+con > dev only > con only.
698 mutex_lock(&pwm_lookup_lock);
700 list_for_each_entry(p, &pwm_lookup_list, list) {
704 if (!dev_id || strcmp(p->dev_id, dev_id))
711 if (!con_id || strcmp(p->con_id, con_id))
730 chip = pwmchip_find_by_name(chosen->provider);
734 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
738 pwm_set_period(pwm, chosen->period);
739 pwm_set_polarity(pwm, chosen->polarity);
742 mutex_unlock(&pwm_lookup_lock);
745 EXPORT_SYMBOL_GPL(pwm_get);
748 * pwm_put() - release a PWM device
751 void pwm_put(struct pwm_device *pwm)
756 mutex_lock(&pwm_lock);
758 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
759 pr_warn("PWM device already freed\n");
763 if (pwm->chip->ops->free)
764 pwm->chip->ops->free(pwm->chip, pwm);
768 module_put(pwm->chip->ops->owner);
770 mutex_unlock(&pwm_lock);
772 EXPORT_SYMBOL_GPL(pwm_put);
774 static void devm_pwm_release(struct device *dev, void *res)
776 pwm_put(*(struct pwm_device **)res);
780 * devm_pwm_get() - resource managed pwm_get()
781 * @dev: device for PWM consumer
782 * @con_id: consumer name
784 * This function performs like pwm_get() but the acquired PWM device will
785 * automatically be released on driver detach.
787 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
788 * error code on failure.
790 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
792 struct pwm_device **ptr, *pwm;
794 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
796 return ERR_PTR(-ENOMEM);
798 pwm = pwm_get(dev, con_id);
801 devres_add(dev, ptr);
808 EXPORT_SYMBOL_GPL(devm_pwm_get);
811 * devm_of_pwm_get() - resource managed of_pwm_get()
812 * @dev: device for PWM consumer
813 * @np: device node to get the PWM from
814 * @con_id: consumer name
816 * This function performs like of_pwm_get() but the acquired PWM device will
817 * automatically be released on driver detach.
819 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
820 * error code on failure.
822 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
825 struct pwm_device **ptr, *pwm;
827 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
829 return ERR_PTR(-ENOMEM);
831 pwm = of_pwm_get(np, con_id);
834 devres_add(dev, ptr);
841 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
843 static int devm_pwm_match(struct device *dev, void *res, void *data)
845 struct pwm_device **p = res;
847 if (WARN_ON(!p || !*p))
854 * devm_pwm_put() - resource managed pwm_put()
855 * @dev: device for PWM consumer
858 * Release a PWM previously allocated using devm_pwm_get(). Calling this
859 * function is usually not needed because devm-allocated resources are
860 * automatically released on driver detach.
862 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
864 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
866 EXPORT_SYMBOL_GPL(devm_pwm_put);
869 * pwm_can_sleep() - report whether PWM access will sleep
872 * Returns: True if accessing the PWM can sleep, false otherwise.
874 bool pwm_can_sleep(struct pwm_device *pwm)
876 return pwm->chip->can_sleep;
878 EXPORT_SYMBOL_GPL(pwm_can_sleep);
880 #ifdef CONFIG_DEBUG_FS
881 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
885 for (i = 0; i < chip->npwm; i++) {
886 struct pwm_device *pwm = &chip->pwms[i];
888 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
890 if (test_bit(PWMF_REQUESTED, &pwm->flags))
891 seq_puts(s, " requested");
893 if (pwm_is_enabled(pwm))
894 seq_puts(s, " enabled");
900 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
902 mutex_lock(&pwm_lock);
905 return seq_list_start(&pwm_chips, *pos);
908 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
912 return seq_list_next(v, &pwm_chips, pos);
915 static void pwm_seq_stop(struct seq_file *s, void *v)
917 mutex_unlock(&pwm_lock);
920 static int pwm_seq_show(struct seq_file *s, void *v)
922 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
924 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
925 chip->dev->bus ? chip->dev->bus->name : "no-bus",
926 dev_name(chip->dev), chip->npwm,
927 (chip->npwm != 1) ? "s" : "");
929 if (chip->ops->dbg_show)
930 chip->ops->dbg_show(chip, s);
932 pwm_dbg_show(chip, s);
937 static const struct seq_operations pwm_seq_ops = {
938 .start = pwm_seq_start,
939 .next = pwm_seq_next,
940 .stop = pwm_seq_stop,
941 .show = pwm_seq_show,
944 static int pwm_seq_open(struct inode *inode, struct file *file)
946 return seq_open(file, &pwm_seq_ops);
949 static const struct file_operations pwm_debugfs_ops = {
950 .owner = THIS_MODULE,
951 .open = pwm_seq_open,
954 .release = seq_release,
957 static int __init pwm_debugfs_init(void)
959 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
964 subsys_initcall(pwm_debugfs_init);
965 #endif /* CONFIG_DEBUG_FS */