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>
35 static DEFINE_MUTEX(pwm_lookup_lock
);
36 static LIST_HEAD(pwm_lookup_list
);
37 static DEFINE_MUTEX(pwm_lock
);
38 static LIST_HEAD(pwm_chips
);
39 static DECLARE_BITMAP(allocated_pwms
, MAX_PWMS
);
40 static RADIX_TREE(pwm_tree
, GFP_KERNEL
);
42 static struct pwm_device
*pwm_to_device(unsigned int pwm
)
44 return radix_tree_lookup(&pwm_tree
, pwm
);
47 static int alloc_pwms(int pwm
, unsigned int count
)
49 unsigned int from
= 0;
58 start
= bitmap_find_next_zero_area(allocated_pwms
, MAX_PWMS
, from
,
61 if (pwm
>= 0 && start
!= pwm
)
64 if (start
+ count
> MAX_PWMS
)
70 static void free_pwms(struct pwm_chip
*chip
)
74 for (i
= 0; i
< chip
->npwm
; i
++) {
75 struct pwm_device
*pwm
= &chip
->pwms
[i
];
76 radix_tree_delete(&pwm_tree
, pwm
->pwm
);
79 bitmap_clear(allocated_pwms
, chip
->base
, chip
->npwm
);
85 static struct pwm_chip
*pwmchip_find_by_name(const char *name
)
87 struct pwm_chip
*chip
;
92 mutex_lock(&pwm_lock
);
94 list_for_each_entry(chip
, &pwm_chips
, list
) {
95 const char *chip_name
= dev_name(chip
->dev
);
97 if (chip_name
&& strcmp(chip_name
, name
) == 0) {
98 mutex_unlock(&pwm_lock
);
103 mutex_unlock(&pwm_lock
);
108 static int pwm_device_request(struct pwm_device
*pwm
, const char *label
)
112 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
))
115 if (!try_module_get(pwm
->chip
->ops
->owner
))
118 if (pwm
->chip
->ops
->request
) {
119 err
= pwm
->chip
->ops
->request(pwm
->chip
, pwm
);
121 module_put(pwm
->chip
->ops
->owner
);
126 set_bit(PWMF_REQUESTED
, &pwm
->flags
);
132 static struct pwm_device
*of_pwm_simple_xlate(struct pwm_chip
*pc
,
133 const struct of_phandle_args
*args
)
135 struct pwm_device
*pwm
;
137 if (pc
->of_pwm_n_cells
< 2)
138 return ERR_PTR(-EINVAL
);
140 if (args
->args
[0] >= pc
->npwm
)
141 return ERR_PTR(-EINVAL
);
143 pwm
= pwm_request_from_chip(pc
, args
->args
[0], NULL
);
147 pwm_set_period(pwm
, args
->args
[1]);
152 void of_pwmchip_add(struct pwm_chip
*chip
)
154 if (!chip
->dev
|| !chip
->dev
->of_node
)
157 if (!chip
->of_xlate
) {
158 chip
->of_xlate
= of_pwm_simple_xlate
;
159 chip
->of_pwm_n_cells
= 2;
162 of_node_get(chip
->dev
->of_node
);
165 void of_pwmchip_remove(struct pwm_chip
*chip
)
167 if (chip
->dev
&& chip
->dev
->of_node
)
168 of_node_put(chip
->dev
->of_node
);
172 * pwm_set_chip_data() - set private chip data for a PWM
174 * @data: pointer to chip-specific data
176 int pwm_set_chip_data(struct pwm_device
*pwm
, void *data
)
181 pwm
->chip_data
= data
;
187 * pwm_get_chip_data() - get private chip data for a PWM
190 void *pwm_get_chip_data(struct pwm_device
*pwm
)
192 return pwm
? pwm
->chip_data
: NULL
;
196 * pwmchip_add() - register a new PWM chip
197 * @chip: the PWM chip to add
199 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
202 int pwmchip_add(struct pwm_chip
*chip
)
204 struct pwm_device
*pwm
;
208 if (!chip
|| !chip
->dev
|| !chip
->ops
|| !chip
->ops
->config
||
209 !chip
->ops
->enable
|| !chip
->ops
->disable
)
212 mutex_lock(&pwm_lock
);
214 ret
= alloc_pwms(chip
->base
, chip
->npwm
);
218 chip
->pwms
= kzalloc(chip
->npwm
* sizeof(*pwm
), GFP_KERNEL
);
226 for (i
= 0; i
< chip
->npwm
; i
++) {
227 pwm
= &chip
->pwms
[i
];
230 pwm
->pwm
= chip
->base
+ i
;
233 radix_tree_insert(&pwm_tree
, pwm
->pwm
, pwm
);
236 bitmap_set(allocated_pwms
, chip
->base
, chip
->npwm
);
238 INIT_LIST_HEAD(&chip
->list
);
239 list_add(&chip
->list
, &pwm_chips
);
243 if (IS_ENABLED(CONFIG_OF
))
244 of_pwmchip_add(chip
);
247 mutex_unlock(&pwm_lock
);
250 EXPORT_SYMBOL_GPL(pwmchip_add
);
253 * pwmchip_remove() - remove a PWM chip
254 * @chip: the PWM chip to remove
256 * Removes a PWM chip. This function may return busy if the PWM chip provides
257 * a PWM device that is still requested.
259 int pwmchip_remove(struct pwm_chip
*chip
)
264 mutex_lock(&pwm_lock
);
266 for (i
= 0; i
< chip
->npwm
; i
++) {
267 struct pwm_device
*pwm
= &chip
->pwms
[i
];
269 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
)) {
275 list_del_init(&chip
->list
);
277 if (IS_ENABLED(CONFIG_OF
))
278 of_pwmchip_remove(chip
);
283 mutex_unlock(&pwm_lock
);
286 EXPORT_SYMBOL_GPL(pwmchip_remove
);
289 * pwm_request() - request a PWM device
290 * @pwm_id: global PWM device index
291 * @label: PWM device label
293 * This function is deprecated, use pwm_get() instead.
295 struct pwm_device
*pwm_request(int pwm
, const char *label
)
297 struct pwm_device
*dev
;
300 if (pwm
< 0 || pwm
>= MAX_PWMS
)
301 return ERR_PTR(-EINVAL
);
303 mutex_lock(&pwm_lock
);
305 dev
= pwm_to_device(pwm
);
307 dev
= ERR_PTR(-EPROBE_DEFER
);
311 err
= pwm_device_request(dev
, label
);
316 mutex_unlock(&pwm_lock
);
320 EXPORT_SYMBOL_GPL(pwm_request
);
323 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
325 * @index: per-chip index of the PWM to request
326 * @label: a literal description string of this PWM
328 * Returns the PWM at the given index of the given PWM chip. A negative error
329 * code is returned if the index is not valid for the specified PWM chip or
330 * if the PWM device cannot be requested.
332 struct pwm_device
*pwm_request_from_chip(struct pwm_chip
*chip
,
336 struct pwm_device
*pwm
;
339 if (!chip
|| index
>= chip
->npwm
)
340 return ERR_PTR(-EINVAL
);
342 mutex_lock(&pwm_lock
);
343 pwm
= &chip
->pwms
[index
];
345 err
= pwm_device_request(pwm
, label
);
349 mutex_unlock(&pwm_lock
);
352 EXPORT_SYMBOL_GPL(pwm_request_from_chip
);
355 * pwm_free() - free a PWM device
358 * This function is deprecated, use pwm_put() instead.
360 void pwm_free(struct pwm_device
*pwm
)
364 EXPORT_SYMBOL_GPL(pwm_free
);
367 * pwm_config() - change a PWM device configuration
369 * @duty_ns: "on" time (in nanoseconds)
370 * @period_ns: duration (in nanoseconds) of one cycle
372 int pwm_config(struct pwm_device
*pwm
, int duty_ns
, int period_ns
)
374 if (!pwm
|| period_ns
== 0 || duty_ns
> period_ns
)
377 return pwm
->chip
->ops
->config(pwm
->chip
, pwm
, duty_ns
, period_ns
);
379 EXPORT_SYMBOL_GPL(pwm_config
);
382 * pwm_enable() - start a PWM output toggling
385 int pwm_enable(struct pwm_device
*pwm
)
387 if (pwm
&& !test_and_set_bit(PWMF_ENABLED
, &pwm
->flags
))
388 return pwm
->chip
->ops
->enable(pwm
->chip
, pwm
);
390 return pwm
? 0 : -EINVAL
;
392 EXPORT_SYMBOL_GPL(pwm_enable
);
395 * pwm_disable() - stop a PWM output toggling
398 void pwm_disable(struct pwm_device
*pwm
)
400 if (pwm
&& test_and_clear_bit(PWMF_ENABLED
, &pwm
->flags
))
401 pwm
->chip
->ops
->disable(pwm
->chip
, pwm
);
403 EXPORT_SYMBOL_GPL(pwm_disable
);
405 static struct pwm_chip
*of_node_to_pwmchip(struct device_node
*np
)
407 struct pwm_chip
*chip
;
409 mutex_lock(&pwm_lock
);
411 list_for_each_entry(chip
, &pwm_chips
, list
)
412 if (chip
->dev
&& chip
->dev
->of_node
== np
) {
413 mutex_unlock(&pwm_lock
);
417 mutex_unlock(&pwm_lock
);
419 return ERR_PTR(-EPROBE_DEFER
);
423 * of_pwm_request() - request a PWM via the PWM framework
424 * @np: device node to get the PWM from
425 * @con_id: consumer name
427 * Returns the PWM device parsed from the phandle and index specified in the
428 * "pwms" property of a device tree node or a negative error-code on failure.
429 * Values parsed from the device tree are stored in the returned PWM device
432 * If con_id is NULL, the first PWM device listed in the "pwms" property will
433 * be requested. Otherwise the "pwm-names" property is used to do a reverse
434 * lookup of the PWM index. This also means that the "pwm-names" property
435 * becomes mandatory for devices that look up the PWM device via the con_id
438 static struct pwm_device
*of_pwm_request(struct device_node
*np
,
441 struct pwm_device
*pwm
= NULL
;
442 struct of_phandle_args args
;
448 index
= of_property_match_string(np
, "pwm-names", con_id
);
450 return ERR_PTR(index
);
453 err
= of_parse_phandle_with_args(np
, "pwms", "#pwm-cells", index
,
456 pr_debug("%s(): can't parse \"pwms\" property\n", __func__
);
460 pc
= of_node_to_pwmchip(args
.np
);
462 pr_debug("%s(): PWM chip not found\n", __func__
);
467 if (args
.args_count
!= pc
->of_pwm_n_cells
) {
468 pr_debug("%s: wrong #pwm-cells for %s\n", np
->full_name
,
470 pwm
= ERR_PTR(-EINVAL
);
474 pwm
= pc
->of_xlate(pc
, &args
);
479 * If a consumer name was not given, try to look it up from the
480 * "pwm-names" property if it exists. Otherwise use the name of
481 * the user device node.
484 err
= of_property_read_string_index(np
, "pwm-names", index
,
493 of_node_put(args
.np
);
499 * pwm_add_table() - register PWM device consumers
500 * @table: array of consumers to register
501 * @num: number of consumers in table
503 void __init
pwm_add_table(struct pwm_lookup
*table
, size_t num
)
505 mutex_lock(&pwm_lookup_lock
);
508 list_add_tail(&table
->list
, &pwm_lookup_list
);
512 mutex_unlock(&pwm_lookup_lock
);
516 * pwm_get() - look up and request a PWM device
517 * @dev: device for PWM consumer
518 * @con_id: consumer name
520 * Lookup is first attempted using DT. If the device was not instantiated from
521 * a device tree, a PWM chip and a relative index is looked up via a table
522 * supplied by board setup code (see pwm_add_table()).
524 * Once a PWM chip has been found the specified PWM device will be requested
525 * and is ready to be used.
527 struct pwm_device
*pwm_get(struct device
*dev
, const char *con_id
)
529 struct pwm_device
*pwm
= ERR_PTR(-EPROBE_DEFER
);
530 const char *dev_id
= dev
? dev_name(dev
): NULL
;
531 struct pwm_chip
*chip
= NULL
;
532 unsigned int index
= 0;
533 unsigned int best
= 0;
534 struct pwm_lookup
*p
;
537 /* look up via DT first */
538 if (IS_ENABLED(CONFIG_OF
) && dev
&& dev
->of_node
)
539 return of_pwm_request(dev
->of_node
, con_id
);
542 * We look up the provider in the static table typically provided by
543 * board setup code. We first try to lookup the consumer device by
544 * name. If the consumer device was passed in as NULL or if no match
545 * was found, we try to find the consumer by directly looking it up
548 * If a match is found, the provider PWM chip is looked up by name
549 * and a PWM device is requested using the PWM device per-chip index.
551 * The lookup algorithm was shamelessly taken from the clock
554 * We do slightly fuzzy matching here:
555 * An entry with a NULL ID is assumed to be a wildcard.
556 * If an entry has a device ID, it must match
557 * If an entry has a connection ID, it must match
558 * Then we take the most specific entry - with the following order
559 * of precedence: dev+con > dev only > con only.
561 mutex_lock(&pwm_lookup_lock
);
563 list_for_each_entry(p
, &pwm_lookup_list
, list
) {
567 if (!dev_id
|| strcmp(p
->dev_id
, dev_id
))
574 if (!con_id
|| strcmp(p
->con_id
, con_id
))
581 chip
= pwmchip_find_by_name(p
->provider
);
592 pwm
= pwm_request_from_chip(chip
, index
, con_id
?: dev_id
);
594 mutex_unlock(&pwm_lookup_lock
);
598 EXPORT_SYMBOL_GPL(pwm_get
);
601 * pwm_put() - release a PWM device
604 void pwm_put(struct pwm_device
*pwm
)
609 mutex_lock(&pwm_lock
);
611 if (!test_and_clear_bit(PWMF_REQUESTED
, &pwm
->flags
)) {
612 pr_warning("PWM device already freed\n");
616 if (pwm
->chip
->ops
->free
)
617 pwm
->chip
->ops
->free(pwm
->chip
, pwm
);
621 module_put(pwm
->chip
->ops
->owner
);
623 mutex_unlock(&pwm_lock
);
625 EXPORT_SYMBOL_GPL(pwm_put
);
627 #ifdef CONFIG_DEBUG_FS
628 static void pwm_dbg_show(struct pwm_chip
*chip
, struct seq_file
*s
)
632 for (i
= 0; i
< chip
->npwm
; i
++) {
633 struct pwm_device
*pwm
= &chip
->pwms
[i
];
635 seq_printf(s
, " pwm-%-3d (%-20.20s):", i
, pwm
->label
);
637 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
))
638 seq_printf(s
, " requested");
640 if (test_bit(PWMF_ENABLED
, &pwm
->flags
))
641 seq_printf(s
, " enabled");
647 static void *pwm_seq_start(struct seq_file
*s
, loff_t
*pos
)
649 mutex_lock(&pwm_lock
);
652 return seq_list_start(&pwm_chips
, *pos
);
655 static void *pwm_seq_next(struct seq_file
*s
, void *v
, loff_t
*pos
)
659 return seq_list_next(v
, &pwm_chips
, pos
);
662 static void pwm_seq_stop(struct seq_file
*s
, void *v
)
664 mutex_unlock(&pwm_lock
);
667 static int pwm_seq_show(struct seq_file
*s
, void *v
)
669 struct pwm_chip
*chip
= list_entry(v
, struct pwm_chip
, list
);
671 seq_printf(s
, "%s%s/%s, %d PWM device%s\n", (char *)s
->private,
672 chip
->dev
->bus
? chip
->dev
->bus
->name
: "no-bus",
673 dev_name(chip
->dev
), chip
->npwm
,
674 (chip
->npwm
!= 1) ? "s" : "");
676 if (chip
->ops
->dbg_show
)
677 chip
->ops
->dbg_show(chip
, s
);
679 pwm_dbg_show(chip
, s
);
684 static const struct seq_operations pwm_seq_ops
= {
685 .start
= pwm_seq_start
,
686 .next
= pwm_seq_next
,
687 .stop
= pwm_seq_stop
,
688 .show
= pwm_seq_show
,
691 static int pwm_seq_open(struct inode
*inode
, struct file
*file
)
693 return seq_open(file
, &pwm_seq_ops
);
696 static const struct file_operations pwm_debugfs_ops
= {
697 .owner
= THIS_MODULE
,
698 .open
= pwm_seq_open
,
701 .release
= seq_release
,
704 static int __init
pwm_debugfs_init(void)
706 debugfs_create_file("pwm", S_IFREG
| S_IRUGO
, NULL
, NULL
,
712 subsys_initcall(pwm_debugfs_init
);
713 #endif /* CONFIG_DEBUG_FS */