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 /* flags in the third cell of the DT PWM specifier */
36 #define PWM_SPEC_POLARITY (1 << 0)
38 static DEFINE_MUTEX(pwm_lookup_lock
);
39 static LIST_HEAD(pwm_lookup_list
);
40 static DEFINE_MUTEX(pwm_lock
);
41 static LIST_HEAD(pwm_chips
);
42 static DECLARE_BITMAP(allocated_pwms
, MAX_PWMS
);
43 static RADIX_TREE(pwm_tree
, GFP_KERNEL
);
45 static struct pwm_device
*pwm_to_device(unsigned int pwm
)
47 return radix_tree_lookup(&pwm_tree
, pwm
);
50 static int alloc_pwms(int pwm
, unsigned int count
)
52 unsigned int from
= 0;
61 start
= bitmap_find_next_zero_area(allocated_pwms
, MAX_PWMS
, from
,
64 if (pwm
>= 0 && start
!= pwm
)
67 if (start
+ count
> MAX_PWMS
)
73 static void free_pwms(struct pwm_chip
*chip
)
77 for (i
= 0; i
< chip
->npwm
; i
++) {
78 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_set_period(pwm
, args
->args
[1]);
152 if (args
->args
[2] & PWM_SPEC_POLARITY
)
153 pwm_set_polarity(pwm
, PWM_POLARITY_INVERSED
);
155 pwm_set_polarity(pwm
, 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_set_period(pwm
, 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
)
196 if (chip
->dev
&& chip
->dev
->of_node
)
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 int pwm_set_chip_data(struct pwm_device
*pwm
, void *data
)
210 pwm
->chip_data
= data
;
214 EXPORT_SYMBOL_GPL(pwm_set_chip_data
);
217 * pwm_get_chip_data() - get private chip data for a PWM
220 void *pwm_get_chip_data(struct pwm_device
*pwm
)
222 return pwm
? pwm
->chip_data
: NULL
;
224 EXPORT_SYMBOL_GPL(pwm_get_chip_data
);
227 * pwmchip_add() - register a new PWM chip
228 * @chip: the PWM chip to add
230 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
233 int pwmchip_add(struct pwm_chip
*chip
)
235 struct pwm_device
*pwm
;
239 if (!chip
|| !chip
->dev
|| !chip
->ops
|| !chip
->ops
->config
||
240 !chip
->ops
->enable
|| !chip
->ops
->disable
)
243 mutex_lock(&pwm_lock
);
245 ret
= alloc_pwms(chip
->base
, chip
->npwm
);
249 chip
->pwms
= kzalloc(chip
->npwm
* sizeof(*pwm
), GFP_KERNEL
);
257 for (i
= 0; i
< chip
->npwm
; i
++) {
258 pwm
= &chip
->pwms
[i
];
261 pwm
->pwm
= chip
->base
+ i
;
264 radix_tree_insert(&pwm_tree
, pwm
->pwm
, pwm
);
267 bitmap_set(allocated_pwms
, chip
->base
, chip
->npwm
);
269 INIT_LIST_HEAD(&chip
->list
);
270 list_add(&chip
->list
, &pwm_chips
);
274 if (IS_ENABLED(CONFIG_OF
))
275 of_pwmchip_add(chip
);
277 pwmchip_sysfs_export(chip
);
280 mutex_unlock(&pwm_lock
);
283 EXPORT_SYMBOL_GPL(pwmchip_add
);
286 * pwmchip_remove() - remove a PWM chip
287 * @chip: the PWM chip to remove
289 * Removes a PWM chip. This function may return busy if the PWM chip provides
290 * a PWM device that is still requested.
292 int pwmchip_remove(struct pwm_chip
*chip
)
297 mutex_lock(&pwm_lock
);
299 for (i
= 0; i
< chip
->npwm
; i
++) {
300 struct pwm_device
*pwm
= &chip
->pwms
[i
];
302 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
)) {
308 list_del_init(&chip
->list
);
310 if (IS_ENABLED(CONFIG_OF
))
311 of_pwmchip_remove(chip
);
315 pwmchip_sysfs_unexport(chip
);
318 mutex_unlock(&pwm_lock
);
321 EXPORT_SYMBOL_GPL(pwmchip_remove
);
324 * pwm_request() - request a PWM device
325 * @pwm_id: global PWM device index
326 * @label: PWM device label
328 * This function is deprecated, use pwm_get() instead.
330 struct pwm_device
*pwm_request(int pwm
, const char *label
)
332 struct pwm_device
*dev
;
335 if (pwm
< 0 || pwm
>= MAX_PWMS
)
336 return ERR_PTR(-EINVAL
);
338 mutex_lock(&pwm_lock
);
340 dev
= pwm_to_device(pwm
);
342 dev
= ERR_PTR(-EPROBE_DEFER
);
346 err
= pwm_device_request(dev
, label
);
351 mutex_unlock(&pwm_lock
);
355 EXPORT_SYMBOL_GPL(pwm_request
);
358 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
360 * @index: per-chip index of the PWM to request
361 * @label: a literal description string of this PWM
363 * Returns the PWM at the given index of the given PWM chip. A negative error
364 * code is returned if the index is not valid for the specified PWM chip or
365 * if the PWM device cannot be requested.
367 struct pwm_device
*pwm_request_from_chip(struct pwm_chip
*chip
,
371 struct pwm_device
*pwm
;
374 if (!chip
|| index
>= chip
->npwm
)
375 return ERR_PTR(-EINVAL
);
377 mutex_lock(&pwm_lock
);
378 pwm
= &chip
->pwms
[index
];
380 err
= pwm_device_request(pwm
, label
);
384 mutex_unlock(&pwm_lock
);
387 EXPORT_SYMBOL_GPL(pwm_request_from_chip
);
390 * pwm_free() - free a PWM device
393 * This function is deprecated, use pwm_put() instead.
395 void pwm_free(struct pwm_device
*pwm
)
399 EXPORT_SYMBOL_GPL(pwm_free
);
402 * pwm_config() - change a PWM device configuration
404 * @duty_ns: "on" time (in nanoseconds)
405 * @period_ns: duration (in nanoseconds) of one cycle
407 int pwm_config(struct pwm_device
*pwm
, int duty_ns
, int period_ns
)
411 if (!pwm
|| duty_ns
< 0 || period_ns
<= 0 || duty_ns
> period_ns
)
414 err
= pwm
->chip
->ops
->config(pwm
->chip
, pwm
, duty_ns
, period_ns
);
418 pwm
->duty_cycle
= duty_ns
;
419 pwm
->period
= period_ns
;
423 EXPORT_SYMBOL_GPL(pwm_config
);
426 * pwm_set_polarity() - configure the polarity of a PWM signal
428 * @polarity: new polarity of the PWM signal
430 * Note that the polarity cannot be configured while the PWM device is enabled
432 int pwm_set_polarity(struct pwm_device
*pwm
, enum pwm_polarity polarity
)
436 if (!pwm
|| !pwm
->chip
->ops
)
439 if (!pwm
->chip
->ops
->set_polarity
)
442 if (test_bit(PWMF_ENABLED
, &pwm
->flags
))
445 err
= pwm
->chip
->ops
->set_polarity(pwm
->chip
, pwm
, polarity
);
449 pwm
->polarity
= polarity
;
453 EXPORT_SYMBOL_GPL(pwm_set_polarity
);
456 * pwm_enable() - start a PWM output toggling
459 int pwm_enable(struct pwm_device
*pwm
)
461 if (pwm
&& !test_and_set_bit(PWMF_ENABLED
, &pwm
->flags
))
462 return pwm
->chip
->ops
->enable(pwm
->chip
, pwm
);
464 return pwm
? 0 : -EINVAL
;
466 EXPORT_SYMBOL_GPL(pwm_enable
);
469 * pwm_disable() - stop a PWM output toggling
472 void pwm_disable(struct pwm_device
*pwm
)
474 if (pwm
&& test_and_clear_bit(PWMF_ENABLED
, &pwm
->flags
))
475 pwm
->chip
->ops
->disable(pwm
->chip
, pwm
);
477 EXPORT_SYMBOL_GPL(pwm_disable
);
479 static struct pwm_chip
*of_node_to_pwmchip(struct device_node
*np
)
481 struct pwm_chip
*chip
;
483 mutex_lock(&pwm_lock
);
485 list_for_each_entry(chip
, &pwm_chips
, list
)
486 if (chip
->dev
&& chip
->dev
->of_node
== np
) {
487 mutex_unlock(&pwm_lock
);
491 mutex_unlock(&pwm_lock
);
493 return ERR_PTR(-EPROBE_DEFER
);
497 * of_pwm_get() - request a PWM via the PWM framework
498 * @np: device node to get the PWM from
499 * @con_id: consumer name
501 * Returns the PWM device parsed from the phandle and index specified in the
502 * "pwms" property of a device tree node or a negative error-code on failure.
503 * Values parsed from the device tree are stored in the returned PWM device
506 * If con_id is NULL, the first PWM device listed in the "pwms" property will
507 * be requested. Otherwise the "pwm-names" property is used to do a reverse
508 * lookup of the PWM index. This also means that the "pwm-names" property
509 * becomes mandatory for devices that look up the PWM device via the con_id
512 struct pwm_device
*of_pwm_get(struct device_node
*np
, const char *con_id
)
514 struct pwm_device
*pwm
= NULL
;
515 struct of_phandle_args args
;
521 index
= of_property_match_string(np
, "pwm-names", con_id
);
523 return ERR_PTR(index
);
526 err
= of_parse_phandle_with_args(np
, "pwms", "#pwm-cells", index
,
529 pr_debug("%s(): can't parse \"pwms\" property\n", __func__
);
533 pc
= of_node_to_pwmchip(args
.np
);
535 pr_debug("%s(): PWM chip not found\n", __func__
);
540 if (args
.args_count
!= pc
->of_pwm_n_cells
) {
541 pr_debug("%s: wrong #pwm-cells for %s\n", np
->full_name
,
543 pwm
= ERR_PTR(-EINVAL
);
547 pwm
= pc
->of_xlate(pc
, &args
);
552 * If a consumer name was not given, try to look it up from the
553 * "pwm-names" property if it exists. Otherwise use the name of
554 * the user device node.
557 err
= of_property_read_string_index(np
, "pwm-names", index
,
566 of_node_put(args
.np
);
570 EXPORT_SYMBOL_GPL(of_pwm_get
);
573 * pwm_add_table() - register PWM device consumers
574 * @table: array of consumers to register
575 * @num: number of consumers in table
577 void __init
pwm_add_table(struct pwm_lookup
*table
, size_t num
)
579 mutex_lock(&pwm_lookup_lock
);
582 list_add_tail(&table
->list
, &pwm_lookup_list
);
586 mutex_unlock(&pwm_lookup_lock
);
590 * pwm_get() - look up and request a PWM device
591 * @dev: device for PWM consumer
592 * @con_id: consumer name
594 * Lookup is first attempted using DT. If the device was not instantiated from
595 * a device tree, a PWM chip and a relative index is looked up via a table
596 * supplied by board setup code (see pwm_add_table()).
598 * Once a PWM chip has been found the specified PWM device will be requested
599 * and is ready to be used.
601 struct pwm_device
*pwm_get(struct device
*dev
, const char *con_id
)
603 struct pwm_device
*pwm
= ERR_PTR(-EPROBE_DEFER
);
604 const char *dev_id
= dev
? dev_name(dev
) : NULL
;
605 struct pwm_chip
*chip
= NULL
;
606 unsigned int index
= 0;
607 unsigned int best
= 0;
608 struct pwm_lookup
*p
;
611 /* look up via DT first */
612 if (IS_ENABLED(CONFIG_OF
) && dev
&& dev
->of_node
)
613 return of_pwm_get(dev
->of_node
, con_id
);
616 * We look up the provider in the static table typically provided by
617 * board setup code. We first try to lookup the consumer device by
618 * name. If the consumer device was passed in as NULL or if no match
619 * was found, we try to find the consumer by directly looking it up
622 * If a match is found, the provider PWM chip is looked up by name
623 * and a PWM device is requested using the PWM device per-chip index.
625 * The lookup algorithm was shamelessly taken from the clock
628 * We do slightly fuzzy matching here:
629 * An entry with a NULL ID is assumed to be a wildcard.
630 * If an entry has a device ID, it must match
631 * If an entry has a connection ID, it must match
632 * Then we take the most specific entry - with the following order
633 * of precedence: dev+con > dev only > con only.
635 mutex_lock(&pwm_lookup_lock
);
637 list_for_each_entry(p
, &pwm_lookup_list
, list
) {
641 if (!dev_id
|| strcmp(p
->dev_id
, dev_id
))
648 if (!con_id
|| strcmp(p
->con_id
, con_id
))
655 chip
= pwmchip_find_by_name(p
->provider
);
666 pwm
= pwm_request_from_chip(chip
, index
, con_id
?: dev_id
);
668 mutex_unlock(&pwm_lookup_lock
);
672 EXPORT_SYMBOL_GPL(pwm_get
);
675 * pwm_put() - release a PWM device
678 void pwm_put(struct pwm_device
*pwm
)
683 mutex_lock(&pwm_lock
);
685 if (!test_and_clear_bit(PWMF_REQUESTED
, &pwm
->flags
)) {
686 pr_warn("PWM device already freed\n");
690 if (pwm
->chip
->ops
->free
)
691 pwm
->chip
->ops
->free(pwm
->chip
, pwm
);
695 module_put(pwm
->chip
->ops
->owner
);
697 mutex_unlock(&pwm_lock
);
699 EXPORT_SYMBOL_GPL(pwm_put
);
701 static void devm_pwm_release(struct device
*dev
, void *res
)
703 pwm_put(*(struct pwm_device
**)res
);
707 * devm_pwm_get() - resource managed pwm_get()
708 * @dev: device for PWM consumer
709 * @con_id: consumer name
711 * This function performs like pwm_get() but the acquired PWM device will
712 * automatically be released on driver detach.
714 struct pwm_device
*devm_pwm_get(struct device
*dev
, const char *con_id
)
716 struct pwm_device
**ptr
, *pwm
;
718 ptr
= devres_alloc(devm_pwm_release
, sizeof(*ptr
), GFP_KERNEL
);
720 return ERR_PTR(-ENOMEM
);
722 pwm
= pwm_get(dev
, con_id
);
725 devres_add(dev
, ptr
);
732 EXPORT_SYMBOL_GPL(devm_pwm_get
);
735 * devm_of_pwm_get() - resource managed of_pwm_get()
736 * @dev: device for PWM consumer
737 * @np: device node to get the PWM from
738 * @con_id: consumer name
740 * This function performs like of_pwm_get() but the acquired PWM device will
741 * automatically be released on driver detach.
743 struct pwm_device
*devm_of_pwm_get(struct device
*dev
, struct device_node
*np
,
746 struct pwm_device
**ptr
, *pwm
;
748 ptr
= devres_alloc(devm_pwm_release
, sizeof(*ptr
), GFP_KERNEL
);
750 return ERR_PTR(-ENOMEM
);
752 pwm
= of_pwm_get(np
, con_id
);
755 devres_add(dev
, ptr
);
762 EXPORT_SYMBOL_GPL(devm_of_pwm_get
);
764 static int devm_pwm_match(struct device
*dev
, void *res
, void *data
)
766 struct pwm_device
**p
= res
;
768 if (WARN_ON(!p
|| !*p
))
775 * devm_pwm_put() - resource managed pwm_put()
776 * @dev: device for PWM consumer
779 * Release a PWM previously allocated using devm_pwm_get(). Calling this
780 * function is usually not needed because devm-allocated resources are
781 * automatically released on driver detach.
783 void devm_pwm_put(struct device
*dev
, struct pwm_device
*pwm
)
785 WARN_ON(devres_release(dev
, devm_pwm_release
, devm_pwm_match
, pwm
));
787 EXPORT_SYMBOL_GPL(devm_pwm_put
);
790 * pwm_can_sleep() - report whether PWM access will sleep
793 * It returns true if accessing the PWM can sleep, false otherwise.
795 bool pwm_can_sleep(struct pwm_device
*pwm
)
797 return pwm
->chip
->can_sleep
;
799 EXPORT_SYMBOL_GPL(pwm_can_sleep
);
801 #ifdef CONFIG_DEBUG_FS
802 static void pwm_dbg_show(struct pwm_chip
*chip
, struct seq_file
*s
)
806 for (i
= 0; i
< chip
->npwm
; i
++) {
807 struct pwm_device
*pwm
= &chip
->pwms
[i
];
809 seq_printf(s
, " pwm-%-3d (%-20.20s):", i
, pwm
->label
);
811 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
))
812 seq_printf(s
, " requested");
814 if (test_bit(PWMF_ENABLED
, &pwm
->flags
))
815 seq_printf(s
, " enabled");
821 static void *pwm_seq_start(struct seq_file
*s
, loff_t
*pos
)
823 mutex_lock(&pwm_lock
);
826 return seq_list_start(&pwm_chips
, *pos
);
829 static void *pwm_seq_next(struct seq_file
*s
, void *v
, loff_t
*pos
)
833 return seq_list_next(v
, &pwm_chips
, pos
);
836 static void pwm_seq_stop(struct seq_file
*s
, void *v
)
838 mutex_unlock(&pwm_lock
);
841 static int pwm_seq_show(struct seq_file
*s
, void *v
)
843 struct pwm_chip
*chip
= list_entry(v
, struct pwm_chip
, list
);
845 seq_printf(s
, "%s%s/%s, %d PWM device%s\n", (char *)s
->private,
846 chip
->dev
->bus
? chip
->dev
->bus
->name
: "no-bus",
847 dev_name(chip
->dev
), chip
->npwm
,
848 (chip
->npwm
!= 1) ? "s" : "");
850 if (chip
->ops
->dbg_show
)
851 chip
->ops
->dbg_show(chip
, s
);
853 pwm_dbg_show(chip
, s
);
858 static const struct seq_operations pwm_seq_ops
= {
859 .start
= pwm_seq_start
,
860 .next
= pwm_seq_next
,
861 .stop
= pwm_seq_stop
,
862 .show
= pwm_seq_show
,
865 static int pwm_seq_open(struct inode
*inode
, struct file
*file
)
867 return seq_open(file
, &pwm_seq_ops
);
870 static const struct file_operations pwm_debugfs_ops
= {
871 .owner
= THIS_MODULE
,
872 .open
= pwm_seq_open
,
875 .release
= seq_release
,
878 static int __init
pwm_debugfs_init(void)
880 debugfs_create_file("pwm", S_IFREG
| S_IRUGO
, NULL
, NULL
,
886 subsys_initcall(pwm_debugfs_init
);
887 #endif /* CONFIG_DEBUG_FS */