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 */