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);
136 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
138 struct pwm_device *pwm;
140 if (pc->of_pwm_n_cells < 3)
141 return ERR_PTR(-EINVAL);
143 if (args->args[0] >= pc->npwm)
144 return ERR_PTR(-EINVAL);
146 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
150 pwm->args.period = args->args[1];
152 if (args->args[2] & PWM_POLARITY_INVERTED)
153 pwm->args.polarity = PWM_POLARITY_INVERSED;
155 pwm->args.polarity = PWM_POLARITY_NORMAL;
159 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
161 static struct pwm_device *
162 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
164 struct pwm_device *pwm;
166 if (pc->of_pwm_n_cells < 2)
167 return ERR_PTR(-EINVAL);
169 if (args->args[0] >= pc->npwm)
170 return ERR_PTR(-EINVAL);
172 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
176 pwm->args.period = args->args[1];
181 static void of_pwmchip_add(struct pwm_chip *chip)
183 if (!chip->dev || !chip->dev->of_node)
186 if (!chip->of_xlate) {
187 chip->of_xlate = of_pwm_simple_xlate;
188 chip->of_pwm_n_cells = 2;
191 of_node_get(chip->dev->of_node);
194 static void of_pwmchip_remove(struct pwm_chip *chip)
197 of_node_put(chip->dev->of_node);
201 * pwm_set_chip_data() - set private chip data for a PWM
203 * @data: pointer to chip-specific data
205 * Returns: 0 on success or a negative error code on failure.
207 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
212 pwm->chip_data = data;
216 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
219 * pwm_get_chip_data() - get private chip data for a PWM
222 * Returns: A pointer to the chip-private data for the PWM device.
224 void *pwm_get_chip_data(struct pwm_device *pwm)
226 return pwm ? pwm->chip_data : NULL;
228 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
230 static bool pwm_ops_check(const struct pwm_ops *ops)
232 /* driver supports legacy, non-atomic operation */
233 if (ops->config && ops->enable && ops->disable)
236 /* driver supports atomic operation */
244 * pwmchip_add_with_polarity() - register a new PWM chip
245 * @chip: the PWM chip to add
246 * @polarity: initial polarity of PWM channels
248 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
249 * will be used. The initial polarity for all channels is specified by the
250 * @polarity parameter.
252 * Returns: 0 on success or a negative error code on failure.
254 int pwmchip_add_with_polarity(struct pwm_chip *chip,
255 enum pwm_polarity polarity)
257 struct pwm_device *pwm;
261 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
264 if (!pwm_ops_check(chip->ops))
267 mutex_lock(&pwm_lock);
269 ret = alloc_pwms(chip->base, chip->npwm);
273 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
281 for (i = 0; i < chip->npwm; i++) {
282 pwm = &chip->pwms[i];
285 pwm->pwm = chip->base + i;
287 pwm->state.polarity = polarity;
289 if (chip->ops->get_state)
290 chip->ops->get_state(chip, pwm, &pwm->state);
292 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
295 bitmap_set(allocated_pwms, chip->base, chip->npwm);
297 INIT_LIST_HEAD(&chip->list);
298 list_add(&chip->list, &pwm_chips);
302 if (IS_ENABLED(CONFIG_OF))
303 of_pwmchip_add(chip);
305 pwmchip_sysfs_export(chip);
308 mutex_unlock(&pwm_lock);
311 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
314 * pwmchip_add() - register a new PWM chip
315 * @chip: the PWM chip to add
317 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
318 * will be used. The initial polarity for all channels is normal.
320 * Returns: 0 on success or a negative error code on failure.
322 int pwmchip_add(struct pwm_chip *chip)
324 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
326 EXPORT_SYMBOL_GPL(pwmchip_add);
329 * pwmchip_remove() - remove a PWM chip
330 * @chip: the PWM chip to remove
332 * Removes a PWM chip. This function may return busy if the PWM chip provides
333 * a PWM device that is still requested.
335 * Returns: 0 on success or a negative error code on failure.
337 int pwmchip_remove(struct pwm_chip *chip)
342 pwmchip_sysfs_unexport_children(chip);
344 mutex_lock(&pwm_lock);
346 for (i = 0; i < chip->npwm; i++) {
347 struct pwm_device *pwm = &chip->pwms[i];
349 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
355 list_del_init(&chip->list);
357 if (IS_ENABLED(CONFIG_OF))
358 of_pwmchip_remove(chip);
362 pwmchip_sysfs_unexport(chip);
365 mutex_unlock(&pwm_lock);
368 EXPORT_SYMBOL_GPL(pwmchip_remove);
371 * pwm_request() - request a PWM device
372 * @pwm: global PWM device index
373 * @label: PWM device label
375 * This function is deprecated, use pwm_get() instead.
377 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
380 struct pwm_device *pwm_request(int pwm, const char *label)
382 struct pwm_device *dev;
385 if (pwm < 0 || pwm >= MAX_PWMS)
386 return ERR_PTR(-EINVAL);
388 mutex_lock(&pwm_lock);
390 dev = pwm_to_device(pwm);
392 dev = ERR_PTR(-EPROBE_DEFER);
396 err = pwm_device_request(dev, label);
401 mutex_unlock(&pwm_lock);
405 EXPORT_SYMBOL_GPL(pwm_request);
408 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
410 * @index: per-chip index of the PWM to request
411 * @label: a literal description string of this PWM
413 * Returns: A pointer to the PWM device at the given index of the given PWM
414 * chip. A negative error code is returned if the index is not valid for the
415 * specified PWM chip or if the PWM device cannot be requested.
417 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
421 struct pwm_device *pwm;
424 if (!chip || index >= chip->npwm)
425 return ERR_PTR(-EINVAL);
427 mutex_lock(&pwm_lock);
428 pwm = &chip->pwms[index];
430 err = pwm_device_request(pwm, label);
434 mutex_unlock(&pwm_lock);
437 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
440 * pwm_free() - free a PWM device
443 * This function is deprecated, use pwm_put() instead.
445 void pwm_free(struct pwm_device *pwm)
449 EXPORT_SYMBOL_GPL(pwm_free);
452 * pwm_apply_state() - atomically apply a new state to a PWM device
454 * @state: new state to apply. This can be adjusted by the PWM driver
455 * if the requested config is not achievable, for example,
456 * ->duty_cycle and ->period might be approximated.
458 int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
465 if (!memcmp(state, &pwm->state, sizeof(*state)))
468 if (pwm->chip->ops->apply) {
469 err = pwm->chip->ops->apply(pwm->chip, pwm, state);
476 * FIXME: restore the initial state in case of error.
478 if (state->polarity != pwm->state.polarity) {
479 if (!pwm->chip->ops->set_polarity)
483 * Changing the polarity of a running PWM is
484 * only allowed when the PWM driver implements
487 if (pwm->state.enabled) {
488 pwm->chip->ops->disable(pwm->chip, pwm);
489 pwm->state.enabled = false;
492 err = pwm->chip->ops->set_polarity(pwm->chip, pwm,
497 pwm->state.polarity = state->polarity;
500 if (state->period != pwm->state.period ||
501 state->duty_cycle != pwm->state.duty_cycle) {
502 err = pwm->chip->ops->config(pwm->chip, pwm,
508 pwm->state.duty_cycle = state->duty_cycle;
509 pwm->state.period = state->period;
512 if (state->enabled != pwm->state.enabled) {
513 if (state->enabled) {
514 err = pwm->chip->ops->enable(pwm->chip, pwm);
518 pwm->chip->ops->disable(pwm->chip, pwm);
521 pwm->state.enabled = state->enabled;
527 EXPORT_SYMBOL_GPL(pwm_apply_state);
530 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
533 * This function will adjust the PWM config to the PWM arguments provided
534 * by the DT or PWM lookup table. This is particularly useful to adapt
535 * the bootloader config to the Linux one.
537 int pwm_adjust_config(struct pwm_device *pwm)
539 struct pwm_state state;
540 struct pwm_args pargs;
542 pwm_get_args(pwm, &pargs);
543 pwm_get_state(pwm, &state);
546 * If the current period is zero it means that either the PWM driver
547 * does not support initial state retrieval or the PWM has not yet
550 * In either case, we setup the new period and polarity, and assign a
554 state.duty_cycle = 0;
555 state.period = pargs.period;
556 state.polarity = pargs.polarity;
558 return pwm_apply_state(pwm, &state);
562 * Adjust the PWM duty cycle/period based on the period value provided
565 if (pargs.period != state.period) {
566 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
568 do_div(dutycycle, state.period);
569 state.duty_cycle = dutycycle;
570 state.period = pargs.period;
574 * If the polarity changed, we should also change the duty cycle.
576 if (pargs.polarity != state.polarity) {
577 state.polarity = pargs.polarity;
578 state.duty_cycle = state.period - state.duty_cycle;
581 return pwm_apply_state(pwm, &state);
583 EXPORT_SYMBOL_GPL(pwm_adjust_config);
585 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
587 struct pwm_chip *chip;
589 mutex_lock(&pwm_lock);
591 list_for_each_entry(chip, &pwm_chips, list)
592 if (chip->dev && chip->dev->of_node == np) {
593 mutex_unlock(&pwm_lock);
597 mutex_unlock(&pwm_lock);
599 return ERR_PTR(-EPROBE_DEFER);
603 * of_pwm_get() - request a PWM via the PWM framework
604 * @np: device node to get the PWM from
605 * @con_id: consumer name
607 * Returns the PWM device parsed from the phandle and index specified in the
608 * "pwms" property of a device tree node or a negative error-code on failure.
609 * Values parsed from the device tree are stored in the returned PWM device
612 * If con_id is NULL, the first PWM device listed in the "pwms" property will
613 * be requested. Otherwise the "pwm-names" property is used to do a reverse
614 * lookup of the PWM index. This also means that the "pwm-names" property
615 * becomes mandatory for devices that look up the PWM device via the con_id
618 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
619 * error code on failure.
621 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
623 struct pwm_device *pwm = NULL;
624 struct of_phandle_args args;
630 index = of_property_match_string(np, "pwm-names", con_id);
632 return ERR_PTR(index);
635 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
638 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
642 pc = of_node_to_pwmchip(args.np);
644 pr_debug("%s(): PWM chip not found\n", __func__);
649 if (args.args_count != pc->of_pwm_n_cells) {
650 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
652 pwm = ERR_PTR(-EINVAL);
656 pwm = pc->of_xlate(pc, &args);
661 * If a consumer name was not given, try to look it up from the
662 * "pwm-names" property if it exists. Otherwise use the name of
663 * the user device node.
666 err = of_property_read_string_index(np, "pwm-names", index,
675 of_node_put(args.np);
679 EXPORT_SYMBOL_GPL(of_pwm_get);
682 * pwm_add_table() - register PWM device consumers
683 * @table: array of consumers to register
684 * @num: number of consumers in table
686 void pwm_add_table(struct pwm_lookup *table, size_t num)
688 mutex_lock(&pwm_lookup_lock);
691 list_add_tail(&table->list, &pwm_lookup_list);
695 mutex_unlock(&pwm_lookup_lock);
699 * pwm_remove_table() - unregister PWM device consumers
700 * @table: array of consumers to unregister
701 * @num: number of consumers in table
703 void pwm_remove_table(struct pwm_lookup *table, size_t num)
705 mutex_lock(&pwm_lookup_lock);
708 list_del(&table->list);
712 mutex_unlock(&pwm_lookup_lock);
716 * pwm_get() - look up and request a PWM device
717 * @dev: device for PWM consumer
718 * @con_id: consumer name
720 * Lookup is first attempted using DT. If the device was not instantiated from
721 * a device tree, a PWM chip and a relative index is looked up via a table
722 * supplied by board setup code (see pwm_add_table()).
724 * Once a PWM chip has been found the specified PWM device will be requested
725 * and is ready to be used.
727 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
728 * error code on failure.
730 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
732 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
733 const char *dev_id = dev ? dev_name(dev) : NULL;
734 struct pwm_chip *chip = NULL;
735 unsigned int best = 0;
736 struct pwm_lookup *p, *chosen = NULL;
739 /* look up via DT first */
740 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
741 return of_pwm_get(dev->of_node, con_id);
744 * We look up the provider in the static table typically provided by
745 * board setup code. We first try to lookup the consumer device by
746 * name. If the consumer device was passed in as NULL or if no match
747 * was found, we try to find the consumer by directly looking it up
750 * If a match is found, the provider PWM chip is looked up by name
751 * and a PWM device is requested using the PWM device per-chip index.
753 * The lookup algorithm was shamelessly taken from the clock
756 * We do slightly fuzzy matching here:
757 * An entry with a NULL ID is assumed to be a wildcard.
758 * If an entry has a device ID, it must match
759 * If an entry has a connection ID, it must match
760 * Then we take the most specific entry - with the following order
761 * of precedence: dev+con > dev only > con only.
763 mutex_lock(&pwm_lookup_lock);
765 list_for_each_entry(p, &pwm_lookup_list, list) {
769 if (!dev_id || strcmp(p->dev_id, dev_id))
776 if (!con_id || strcmp(p->con_id, con_id))
793 pwm = ERR_PTR(-ENODEV);
797 chip = pwmchip_find_by_name(chosen->provider);
801 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
805 pwm->args.period = chosen->period;
806 pwm->args.polarity = chosen->polarity;
809 mutex_unlock(&pwm_lookup_lock);
812 EXPORT_SYMBOL_GPL(pwm_get);
815 * pwm_put() - release a PWM device
818 void pwm_put(struct pwm_device *pwm)
823 mutex_lock(&pwm_lock);
825 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
826 pr_warn("PWM device already freed\n");
830 if (pwm->chip->ops->free)
831 pwm->chip->ops->free(pwm->chip, pwm);
835 module_put(pwm->chip->ops->owner);
837 mutex_unlock(&pwm_lock);
839 EXPORT_SYMBOL_GPL(pwm_put);
841 static void devm_pwm_release(struct device *dev, void *res)
843 pwm_put(*(struct pwm_device **)res);
847 * devm_pwm_get() - resource managed pwm_get()
848 * @dev: device for PWM consumer
849 * @con_id: consumer name
851 * This function performs like pwm_get() but the acquired PWM device will
852 * automatically be released on driver detach.
854 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
855 * error code on failure.
857 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
859 struct pwm_device **ptr, *pwm;
861 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
863 return ERR_PTR(-ENOMEM);
865 pwm = pwm_get(dev, con_id);
868 devres_add(dev, ptr);
875 EXPORT_SYMBOL_GPL(devm_pwm_get);
878 * devm_of_pwm_get() - resource managed of_pwm_get()
879 * @dev: device for PWM consumer
880 * @np: device node to get the PWM from
881 * @con_id: consumer name
883 * This function performs like of_pwm_get() but the acquired PWM device will
884 * automatically be released on driver detach.
886 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
887 * error code on failure.
889 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
892 struct pwm_device **ptr, *pwm;
894 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
896 return ERR_PTR(-ENOMEM);
898 pwm = of_pwm_get(np, con_id);
901 devres_add(dev, ptr);
908 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
910 static int devm_pwm_match(struct device *dev, void *res, void *data)
912 struct pwm_device **p = res;
914 if (WARN_ON(!p || !*p))
921 * devm_pwm_put() - resource managed pwm_put()
922 * @dev: device for PWM consumer
925 * Release a PWM previously allocated using devm_pwm_get(). Calling this
926 * function is usually not needed because devm-allocated resources are
927 * automatically released on driver detach.
929 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
931 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
933 EXPORT_SYMBOL_GPL(devm_pwm_put);
936 * pwm_can_sleep() - report whether PWM access will sleep
939 * Returns: True if accessing the PWM can sleep, false otherwise.
941 bool pwm_can_sleep(struct pwm_device *pwm)
945 EXPORT_SYMBOL_GPL(pwm_can_sleep);
947 #ifdef CONFIG_DEBUG_FS
948 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
952 for (i = 0; i < chip->npwm; i++) {
953 struct pwm_device *pwm = &chip->pwms[i];
954 struct pwm_state state;
956 pwm_get_state(pwm, &state);
958 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
960 if (test_bit(PWMF_REQUESTED, &pwm->flags))
961 seq_puts(s, " requested");
964 seq_puts(s, " enabled");
970 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
972 mutex_lock(&pwm_lock);
975 return seq_list_start(&pwm_chips, *pos);
978 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
982 return seq_list_next(v, &pwm_chips, pos);
985 static void pwm_seq_stop(struct seq_file *s, void *v)
987 mutex_unlock(&pwm_lock);
990 static int pwm_seq_show(struct seq_file *s, void *v)
992 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
994 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
995 chip->dev->bus ? chip->dev->bus->name : "no-bus",
996 dev_name(chip->dev), chip->npwm,
997 (chip->npwm != 1) ? "s" : "");
999 if (chip->ops->dbg_show)
1000 chip->ops->dbg_show(chip, s);
1002 pwm_dbg_show(chip, s);
1007 static const struct seq_operations pwm_seq_ops = {
1008 .start = pwm_seq_start,
1009 .next = pwm_seq_next,
1010 .stop = pwm_seq_stop,
1011 .show = pwm_seq_show,
1014 static int pwm_seq_open(struct inode *inode, struct file *file)
1016 return seq_open(file, &pwm_seq_ops);
1019 static const struct file_operations pwm_debugfs_ops = {
1020 .owner = THIS_MODULE,
1021 .open = pwm_seq_open,
1023 .llseek = seq_lseek,
1024 .release = seq_release,
1027 static int __init pwm_debugfs_init(void)
1029 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1034 subsys_initcall(pwm_debugfs_init);
1035 #endif /* CONFIG_DEBUG_FS */