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
)
195 if (chip
->dev
&& chip
->dev
->of_node
)
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() - register a new PWM chip
227 * @chip: the PWM chip to add
229 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
232 int pwmchip_add(struct pwm_chip
*chip
)
234 struct pwm_device
*pwm
;
238 if (!chip
|| !chip
->dev
|| !chip
->ops
|| !chip
->ops
->config
||
239 !chip
->ops
->enable
|| !chip
->ops
->disable
)
242 mutex_lock(&pwm_lock
);
244 ret
= alloc_pwms(chip
->base
, chip
->npwm
);
248 chip
->pwms
= kzalloc(chip
->npwm
* sizeof(*pwm
), GFP_KERNEL
);
256 for (i
= 0; i
< chip
->npwm
; i
++) {
257 pwm
= &chip
->pwms
[i
];
260 pwm
->pwm
= chip
->base
+ i
;
263 radix_tree_insert(&pwm_tree
, pwm
->pwm
, pwm
);
266 bitmap_set(allocated_pwms
, chip
->base
, chip
->npwm
);
268 INIT_LIST_HEAD(&chip
->list
);
269 list_add(&chip
->list
, &pwm_chips
);
273 if (IS_ENABLED(CONFIG_OF
))
274 of_pwmchip_add(chip
);
276 pwmchip_sysfs_export(chip
);
279 mutex_unlock(&pwm_lock
);
282 EXPORT_SYMBOL_GPL(pwmchip_add
);
285 * pwmchip_remove() - remove a PWM chip
286 * @chip: the PWM chip to remove
288 * Removes a PWM chip. This function may return busy if the PWM chip provides
289 * a PWM device that is still requested.
291 int pwmchip_remove(struct pwm_chip
*chip
)
296 mutex_lock(&pwm_lock
);
298 for (i
= 0; i
< chip
->npwm
; i
++) {
299 struct pwm_device
*pwm
= &chip
->pwms
[i
];
301 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
)) {
307 list_del_init(&chip
->list
);
309 if (IS_ENABLED(CONFIG_OF
))
310 of_pwmchip_remove(chip
);
314 pwmchip_sysfs_unexport(chip
);
317 mutex_unlock(&pwm_lock
);
320 EXPORT_SYMBOL_GPL(pwmchip_remove
);
323 * pwm_request() - request a PWM device
324 * @pwm_id: global PWM device index
325 * @label: PWM device label
327 * This function is deprecated, use pwm_get() instead.
329 struct pwm_device
*pwm_request(int pwm
, const char *label
)
331 struct pwm_device
*dev
;
334 if (pwm
< 0 || pwm
>= MAX_PWMS
)
335 return ERR_PTR(-EINVAL
);
337 mutex_lock(&pwm_lock
);
339 dev
= pwm_to_device(pwm
);
341 dev
= ERR_PTR(-EPROBE_DEFER
);
345 err
= pwm_device_request(dev
, label
);
350 mutex_unlock(&pwm_lock
);
354 EXPORT_SYMBOL_GPL(pwm_request
);
357 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
359 * @index: per-chip index of the PWM to request
360 * @label: a literal description string of this PWM
362 * Returns the PWM at the given index of the given PWM chip. A negative error
363 * code is returned if the index is not valid for the specified PWM chip or
364 * if the PWM device cannot be requested.
366 struct pwm_device
*pwm_request_from_chip(struct pwm_chip
*chip
,
370 struct pwm_device
*pwm
;
373 if (!chip
|| index
>= chip
->npwm
)
374 return ERR_PTR(-EINVAL
);
376 mutex_lock(&pwm_lock
);
377 pwm
= &chip
->pwms
[index
];
379 err
= pwm_device_request(pwm
, label
);
383 mutex_unlock(&pwm_lock
);
386 EXPORT_SYMBOL_GPL(pwm_request_from_chip
);
389 * pwm_free() - free a PWM device
392 * This function is deprecated, use pwm_put() instead.
394 void pwm_free(struct pwm_device
*pwm
)
398 EXPORT_SYMBOL_GPL(pwm_free
);
401 * pwm_config() - change a PWM device configuration
403 * @duty_ns: "on" time (in nanoseconds)
404 * @period_ns: duration (in nanoseconds) of one cycle
406 int pwm_config(struct pwm_device
*pwm
, int duty_ns
, int period_ns
)
410 if (!pwm
|| duty_ns
< 0 || period_ns
<= 0 || duty_ns
> period_ns
)
413 err
= pwm
->chip
->ops
->config(pwm
->chip
, pwm
, duty_ns
, period_ns
);
417 pwm
->duty_cycle
= duty_ns
;
418 pwm
->period
= period_ns
;
422 EXPORT_SYMBOL_GPL(pwm_config
);
425 * pwm_set_polarity() - configure the polarity of a PWM signal
427 * @polarity: new polarity of the PWM signal
429 * Note that the polarity cannot be configured while the PWM device is enabled
431 int pwm_set_polarity(struct pwm_device
*pwm
, enum pwm_polarity polarity
)
435 if (!pwm
|| !pwm
->chip
->ops
)
438 if (!pwm
->chip
->ops
->set_polarity
)
441 if (test_bit(PWMF_ENABLED
, &pwm
->flags
))
444 err
= pwm
->chip
->ops
->set_polarity(pwm
->chip
, pwm
, polarity
);
448 pwm
->polarity
= polarity
;
452 EXPORT_SYMBOL_GPL(pwm_set_polarity
);
455 * pwm_enable() - start a PWM output toggling
458 int pwm_enable(struct pwm_device
*pwm
)
460 if (pwm
&& !test_and_set_bit(PWMF_ENABLED
, &pwm
->flags
))
461 return pwm
->chip
->ops
->enable(pwm
->chip
, pwm
);
463 return pwm
? 0 : -EINVAL
;
465 EXPORT_SYMBOL_GPL(pwm_enable
);
468 * pwm_disable() - stop a PWM output toggling
471 void pwm_disable(struct pwm_device
*pwm
)
473 if (pwm
&& test_and_clear_bit(PWMF_ENABLED
, &pwm
->flags
))
474 pwm
->chip
->ops
->disable(pwm
->chip
, pwm
);
476 EXPORT_SYMBOL_GPL(pwm_disable
);
478 static struct pwm_chip
*of_node_to_pwmchip(struct device_node
*np
)
480 struct pwm_chip
*chip
;
482 mutex_lock(&pwm_lock
);
484 list_for_each_entry(chip
, &pwm_chips
, list
)
485 if (chip
->dev
&& chip
->dev
->of_node
== np
) {
486 mutex_unlock(&pwm_lock
);
490 mutex_unlock(&pwm_lock
);
492 return ERR_PTR(-EPROBE_DEFER
);
496 * of_pwm_get() - request a PWM via the PWM framework
497 * @np: device node to get the PWM from
498 * @con_id: consumer name
500 * Returns the PWM device parsed from the phandle and index specified in the
501 * "pwms" property of a device tree node or a negative error-code on failure.
502 * Values parsed from the device tree are stored in the returned PWM device
505 * If con_id is NULL, the first PWM device listed in the "pwms" property will
506 * be requested. Otherwise the "pwm-names" property is used to do a reverse
507 * lookup of the PWM index. This also means that the "pwm-names" property
508 * becomes mandatory for devices that look up the PWM device via the con_id
511 struct pwm_device
*of_pwm_get(struct device_node
*np
, const char *con_id
)
513 struct pwm_device
*pwm
= NULL
;
514 struct of_phandle_args args
;
520 index
= of_property_match_string(np
, "pwm-names", con_id
);
522 return ERR_PTR(index
);
525 err
= of_parse_phandle_with_args(np
, "pwms", "#pwm-cells", index
,
528 pr_debug("%s(): can't parse \"pwms\" property\n", __func__
);
532 pc
= of_node_to_pwmchip(args
.np
);
534 pr_debug("%s(): PWM chip not found\n", __func__
);
539 if (args
.args_count
!= pc
->of_pwm_n_cells
) {
540 pr_debug("%s: wrong #pwm-cells for %s\n", np
->full_name
,
542 pwm
= ERR_PTR(-EINVAL
);
546 pwm
= pc
->of_xlate(pc
, &args
);
551 * If a consumer name was not given, try to look it up from the
552 * "pwm-names" property if it exists. Otherwise use the name of
553 * the user device node.
556 err
= of_property_read_string_index(np
, "pwm-names", index
,
565 of_node_put(args
.np
);
569 EXPORT_SYMBOL_GPL(of_pwm_get
);
572 * pwm_add_table() - register PWM device consumers
573 * @table: array of consumers to register
574 * @num: number of consumers in table
576 void __init
pwm_add_table(struct pwm_lookup
*table
, size_t num
)
578 mutex_lock(&pwm_lookup_lock
);
581 list_add_tail(&table
->list
, &pwm_lookup_list
);
585 mutex_unlock(&pwm_lookup_lock
);
589 * pwm_get() - look up and request a PWM device
590 * @dev: device for PWM consumer
591 * @con_id: consumer name
593 * Lookup is first attempted using DT. If the device was not instantiated from
594 * a device tree, a PWM chip and a relative index is looked up via a table
595 * supplied by board setup code (see pwm_add_table()).
597 * Once a PWM chip has been found the specified PWM device will be requested
598 * and is ready to be used.
600 struct pwm_device
*pwm_get(struct device
*dev
, const char *con_id
)
602 struct pwm_device
*pwm
= ERR_PTR(-EPROBE_DEFER
);
603 const char *dev_id
= dev
? dev_name(dev
) : NULL
;
604 struct pwm_chip
*chip
= NULL
;
605 unsigned int index
= 0;
606 unsigned int best
= 0;
607 struct pwm_lookup
*p
;
610 /* look up via DT first */
611 if (IS_ENABLED(CONFIG_OF
) && dev
&& dev
->of_node
)
612 return of_pwm_get(dev
->of_node
, con_id
);
615 * We look up the provider in the static table typically provided by
616 * board setup code. We first try to lookup the consumer device by
617 * name. If the consumer device was passed in as NULL or if no match
618 * was found, we try to find the consumer by directly looking it up
621 * If a match is found, the provider PWM chip is looked up by name
622 * and a PWM device is requested using the PWM device per-chip index.
624 * The lookup algorithm was shamelessly taken from the clock
627 * We do slightly fuzzy matching here:
628 * An entry with a NULL ID is assumed to be a wildcard.
629 * If an entry has a device ID, it must match
630 * If an entry has a connection ID, it must match
631 * Then we take the most specific entry - with the following order
632 * of precedence: dev+con > dev only > con only.
634 mutex_lock(&pwm_lookup_lock
);
636 list_for_each_entry(p
, &pwm_lookup_list
, list
) {
640 if (!dev_id
|| strcmp(p
->dev_id
, dev_id
))
647 if (!con_id
|| strcmp(p
->con_id
, con_id
))
654 chip
= pwmchip_find_by_name(p
->provider
);
665 pwm
= pwm_request_from_chip(chip
, index
, con_id
?: dev_id
);
667 mutex_unlock(&pwm_lookup_lock
);
671 EXPORT_SYMBOL_GPL(pwm_get
);
674 * pwm_put() - release a PWM device
677 void pwm_put(struct pwm_device
*pwm
)
682 mutex_lock(&pwm_lock
);
684 if (!test_and_clear_bit(PWMF_REQUESTED
, &pwm
->flags
)) {
685 pr_warn("PWM device already freed\n");
689 if (pwm
->chip
->ops
->free
)
690 pwm
->chip
->ops
->free(pwm
->chip
, pwm
);
694 module_put(pwm
->chip
->ops
->owner
);
696 mutex_unlock(&pwm_lock
);
698 EXPORT_SYMBOL_GPL(pwm_put
);
700 static void devm_pwm_release(struct device
*dev
, void *res
)
702 pwm_put(*(struct pwm_device
**)res
);
706 * devm_pwm_get() - resource managed pwm_get()
707 * @dev: device for PWM consumer
708 * @con_id: consumer name
710 * This function performs like pwm_get() but the acquired PWM device will
711 * automatically be released on driver detach.
713 struct pwm_device
*devm_pwm_get(struct device
*dev
, const char *con_id
)
715 struct pwm_device
**ptr
, *pwm
;
717 ptr
= devres_alloc(devm_pwm_release
, sizeof(*ptr
), GFP_KERNEL
);
719 return ERR_PTR(-ENOMEM
);
721 pwm
= pwm_get(dev
, con_id
);
724 devres_add(dev
, ptr
);
731 EXPORT_SYMBOL_GPL(devm_pwm_get
);
734 * devm_of_pwm_get() - resource managed of_pwm_get()
735 * @dev: device for PWM consumer
736 * @np: device node to get the PWM from
737 * @con_id: consumer name
739 * This function performs like of_pwm_get() but the acquired PWM device will
740 * automatically be released on driver detach.
742 struct pwm_device
*devm_of_pwm_get(struct device
*dev
, struct device_node
*np
,
745 struct pwm_device
**ptr
, *pwm
;
747 ptr
= devres_alloc(devm_pwm_release
, sizeof(*ptr
), GFP_KERNEL
);
749 return ERR_PTR(-ENOMEM
);
751 pwm
= of_pwm_get(np
, con_id
);
754 devres_add(dev
, ptr
);
761 EXPORT_SYMBOL_GPL(devm_of_pwm_get
);
763 static int devm_pwm_match(struct device
*dev
, void *res
, void *data
)
765 struct pwm_device
**p
= res
;
767 if (WARN_ON(!p
|| !*p
))
774 * devm_pwm_put() - resource managed pwm_put()
775 * @dev: device for PWM consumer
778 * Release a PWM previously allocated using devm_pwm_get(). Calling this
779 * function is usually not needed because devm-allocated resources are
780 * automatically released on driver detach.
782 void devm_pwm_put(struct device
*dev
, struct pwm_device
*pwm
)
784 WARN_ON(devres_release(dev
, devm_pwm_release
, devm_pwm_match
, pwm
));
786 EXPORT_SYMBOL_GPL(devm_pwm_put
);
789 * pwm_can_sleep() - report whether PWM access will sleep
792 * It returns true if accessing the PWM can sleep, false otherwise.
794 bool pwm_can_sleep(struct pwm_device
*pwm
)
796 return pwm
->chip
->can_sleep
;
798 EXPORT_SYMBOL_GPL(pwm_can_sleep
);
800 #ifdef CONFIG_DEBUG_FS
801 static void pwm_dbg_show(struct pwm_chip
*chip
, struct seq_file
*s
)
805 for (i
= 0; i
< chip
->npwm
; i
++) {
806 struct pwm_device
*pwm
= &chip
->pwms
[i
];
808 seq_printf(s
, " pwm-%-3d (%-20.20s):", i
, pwm
->label
);
810 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
))
811 seq_puts(s
, " requested");
813 if (test_bit(PWMF_ENABLED
, &pwm
->flags
))
814 seq_puts(s
, " enabled");
820 static void *pwm_seq_start(struct seq_file
*s
, loff_t
*pos
)
822 mutex_lock(&pwm_lock
);
825 return seq_list_start(&pwm_chips
, *pos
);
828 static void *pwm_seq_next(struct seq_file
*s
, void *v
, loff_t
*pos
)
832 return seq_list_next(v
, &pwm_chips
, pos
);
835 static void pwm_seq_stop(struct seq_file
*s
, void *v
)
837 mutex_unlock(&pwm_lock
);
840 static int pwm_seq_show(struct seq_file
*s
, void *v
)
842 struct pwm_chip
*chip
= list_entry(v
, struct pwm_chip
, list
);
844 seq_printf(s
, "%s%s/%s, %d PWM device%s\n", (char *)s
->private,
845 chip
->dev
->bus
? chip
->dev
->bus
->name
: "no-bus",
846 dev_name(chip
->dev
), chip
->npwm
,
847 (chip
->npwm
!= 1) ? "s" : "");
849 if (chip
->ops
->dbg_show
)
850 chip
->ops
->dbg_show(chip
, s
);
852 pwm_dbg_show(chip
, s
);
857 static const struct seq_operations pwm_seq_ops
= {
858 .start
= pwm_seq_start
,
859 .next
= pwm_seq_next
,
860 .stop
= pwm_seq_stop
,
861 .show
= pwm_seq_show
,
864 static int pwm_seq_open(struct inode
*inode
, struct file
*file
)
866 return seq_open(file
, &pwm_seq_ops
);
869 static const struct file_operations pwm_debugfs_ops
= {
870 .owner
= THIS_MODULE
,
871 .open
= pwm_seq_open
,
874 .release
= seq_release
,
877 static int __init
pwm_debugfs_init(void)
879 debugfs_create_file("pwm", S_IFREG
| S_IRUGO
, NULL
, NULL
,
885 subsys_initcall(pwm_debugfs_init
);
886 #endif /* CONFIG_DEBUG_FS */