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 mutex_lock(&pwm_lock
);
344 for (i
= 0; i
< chip
->npwm
; i
++) {
345 struct pwm_device
*pwm
= &chip
->pwms
[i
];
347 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
)) {
353 list_del_init(&chip
->list
);
355 if (IS_ENABLED(CONFIG_OF
))
356 of_pwmchip_remove(chip
);
360 pwmchip_sysfs_unexport(chip
);
363 mutex_unlock(&pwm_lock
);
366 EXPORT_SYMBOL_GPL(pwmchip_remove
);
369 * pwm_request() - request a PWM device
370 * @pwm: global PWM device index
371 * @label: PWM device label
373 * This function is deprecated, use pwm_get() instead.
375 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
378 struct pwm_device
*pwm_request(int pwm
, const char *label
)
380 struct pwm_device
*dev
;
383 if (pwm
< 0 || pwm
>= MAX_PWMS
)
384 return ERR_PTR(-EINVAL
);
386 mutex_lock(&pwm_lock
);
388 dev
= pwm_to_device(pwm
);
390 dev
= ERR_PTR(-EPROBE_DEFER
);
394 err
= pwm_device_request(dev
, label
);
399 mutex_unlock(&pwm_lock
);
403 EXPORT_SYMBOL_GPL(pwm_request
);
406 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
408 * @index: per-chip index of the PWM to request
409 * @label: a literal description string of this PWM
411 * Returns: A pointer to the PWM device at the given index of the given PWM
412 * chip. A negative error code is returned if the index is not valid for the
413 * specified PWM chip or if the PWM device cannot be requested.
415 struct pwm_device
*pwm_request_from_chip(struct pwm_chip
*chip
,
419 struct pwm_device
*pwm
;
422 if (!chip
|| index
>= chip
->npwm
)
423 return ERR_PTR(-EINVAL
);
425 mutex_lock(&pwm_lock
);
426 pwm
= &chip
->pwms
[index
];
428 err
= pwm_device_request(pwm
, label
);
432 mutex_unlock(&pwm_lock
);
435 EXPORT_SYMBOL_GPL(pwm_request_from_chip
);
438 * pwm_free() - free a PWM device
441 * This function is deprecated, use pwm_put() instead.
443 void pwm_free(struct pwm_device
*pwm
)
447 EXPORT_SYMBOL_GPL(pwm_free
);
450 * pwm_apply_state() - atomically apply a new state to a PWM device
452 * @state: new state to apply. This can be adjusted by the PWM driver
453 * if the requested config is not achievable, for example,
454 * ->duty_cycle and ->period might be approximated.
456 int pwm_apply_state(struct pwm_device
*pwm
, struct pwm_state
*state
)
460 if (!pwm
|| !state
|| !state
->period
||
461 state
->duty_cycle
> state
->period
)
464 if (!memcmp(state
, &pwm
->state
, sizeof(*state
)))
467 if (pwm
->chip
->ops
->apply
) {
468 err
= pwm
->chip
->ops
->apply(pwm
->chip
, pwm
, state
);
475 * FIXME: restore the initial state in case of error.
477 if (state
->polarity
!= pwm
->state
.polarity
) {
478 if (!pwm
->chip
->ops
->set_polarity
)
482 * Changing the polarity of a running PWM is
483 * only allowed when the PWM driver implements
486 if (pwm
->state
.enabled
) {
487 pwm
->chip
->ops
->disable(pwm
->chip
, pwm
);
488 pwm
->state
.enabled
= false;
491 err
= pwm
->chip
->ops
->set_polarity(pwm
->chip
, pwm
,
496 pwm
->state
.polarity
= state
->polarity
;
499 if (state
->period
!= pwm
->state
.period
||
500 state
->duty_cycle
!= pwm
->state
.duty_cycle
) {
501 err
= pwm
->chip
->ops
->config(pwm
->chip
, pwm
,
507 pwm
->state
.duty_cycle
= state
->duty_cycle
;
508 pwm
->state
.period
= state
->period
;
511 if (state
->enabled
!= pwm
->state
.enabled
) {
512 if (state
->enabled
) {
513 err
= pwm
->chip
->ops
->enable(pwm
->chip
, pwm
);
517 pwm
->chip
->ops
->disable(pwm
->chip
, pwm
);
520 pwm
->state
.enabled
= state
->enabled
;
526 EXPORT_SYMBOL_GPL(pwm_apply_state
);
529 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
532 * This function will adjust the PWM config to the PWM arguments provided
533 * by the DT or PWM lookup table. This is particularly useful to adapt
534 * the bootloader config to the Linux one.
536 int pwm_adjust_config(struct pwm_device
*pwm
)
538 struct pwm_state state
;
539 struct pwm_args pargs
;
541 pwm_get_args(pwm
, &pargs
);
542 pwm_get_state(pwm
, &state
);
545 * If the current period is zero it means that either the PWM driver
546 * does not support initial state retrieval or the PWM has not yet
549 * In either case, we setup the new period and polarity, and assign a
553 state
.duty_cycle
= 0;
554 state
.period
= pargs
.period
;
555 state
.polarity
= pargs
.polarity
;
557 return pwm_apply_state(pwm
, &state
);
561 * Adjust the PWM duty cycle/period based on the period value provided
564 if (pargs
.period
!= state
.period
) {
565 u64 dutycycle
= (u64
)state
.duty_cycle
* pargs
.period
;
567 do_div(dutycycle
, state
.period
);
568 state
.duty_cycle
= dutycycle
;
569 state
.period
= pargs
.period
;
573 * If the polarity changed, we should also change the duty cycle.
575 if (pargs
.polarity
!= state
.polarity
) {
576 state
.polarity
= pargs
.polarity
;
577 state
.duty_cycle
= state
.period
- state
.duty_cycle
;
580 return pwm_apply_state(pwm
, &state
);
582 EXPORT_SYMBOL_GPL(pwm_adjust_config
);
584 static struct pwm_chip
*of_node_to_pwmchip(struct device_node
*np
)
586 struct pwm_chip
*chip
;
588 mutex_lock(&pwm_lock
);
590 list_for_each_entry(chip
, &pwm_chips
, list
)
591 if (chip
->dev
&& chip
->dev
->of_node
== np
) {
592 mutex_unlock(&pwm_lock
);
596 mutex_unlock(&pwm_lock
);
598 return ERR_PTR(-EPROBE_DEFER
);
602 * of_pwm_get() - request a PWM via the PWM framework
603 * @np: device node to get the PWM from
604 * @con_id: consumer name
606 * Returns the PWM device parsed from the phandle and index specified in the
607 * "pwms" property of a device tree node or a negative error-code on failure.
608 * Values parsed from the device tree are stored in the returned PWM device
611 * If con_id is NULL, the first PWM device listed in the "pwms" property will
612 * be requested. Otherwise the "pwm-names" property is used to do a reverse
613 * lookup of the PWM index. This also means that the "pwm-names" property
614 * becomes mandatory for devices that look up the PWM device via the con_id
617 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
618 * error code on failure.
620 struct pwm_device
*of_pwm_get(struct device_node
*np
, const char *con_id
)
622 struct pwm_device
*pwm
= NULL
;
623 struct of_phandle_args args
;
629 index
= of_property_match_string(np
, "pwm-names", con_id
);
631 return ERR_PTR(index
);
634 err
= of_parse_phandle_with_args(np
, "pwms", "#pwm-cells", index
,
637 pr_debug("%s(): can't parse \"pwms\" property\n", __func__
);
641 pc
= of_node_to_pwmchip(args
.np
);
643 pr_debug("%s(): PWM chip not found\n", __func__
);
648 if (args
.args_count
!= pc
->of_pwm_n_cells
) {
649 pr_debug("%s: wrong #pwm-cells for %s\n", np
->full_name
,
651 pwm
= ERR_PTR(-EINVAL
);
655 pwm
= pc
->of_xlate(pc
, &args
);
660 * If a consumer name was not given, try to look it up from the
661 * "pwm-names" property if it exists. Otherwise use the name of
662 * the user device node.
665 err
= of_property_read_string_index(np
, "pwm-names", index
,
674 of_node_put(args
.np
);
678 EXPORT_SYMBOL_GPL(of_pwm_get
);
681 * pwm_add_table() - register PWM device consumers
682 * @table: array of consumers to register
683 * @num: number of consumers in table
685 void pwm_add_table(struct pwm_lookup
*table
, size_t num
)
687 mutex_lock(&pwm_lookup_lock
);
690 list_add_tail(&table
->list
, &pwm_lookup_list
);
694 mutex_unlock(&pwm_lookup_lock
);
698 * pwm_remove_table() - unregister PWM device consumers
699 * @table: array of consumers to unregister
700 * @num: number of consumers in table
702 void pwm_remove_table(struct pwm_lookup
*table
, size_t num
)
704 mutex_lock(&pwm_lookup_lock
);
707 list_del(&table
->list
);
711 mutex_unlock(&pwm_lookup_lock
);
715 * pwm_get() - look up and request a PWM device
716 * @dev: device for PWM consumer
717 * @con_id: consumer name
719 * Lookup is first attempted using DT. If the device was not instantiated from
720 * a device tree, a PWM chip and a relative index is looked up via a table
721 * supplied by board setup code (see pwm_add_table()).
723 * Once a PWM chip has been found the specified PWM device will be requested
724 * and is ready to be used.
726 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
727 * error code on failure.
729 struct pwm_device
*pwm_get(struct device
*dev
, const char *con_id
)
731 struct pwm_device
*pwm
= ERR_PTR(-EPROBE_DEFER
);
732 const char *dev_id
= dev
? dev_name(dev
) : NULL
;
733 struct pwm_chip
*chip
= NULL
;
734 unsigned int best
= 0;
735 struct pwm_lookup
*p
, *chosen
= NULL
;
738 /* look up via DT first */
739 if (IS_ENABLED(CONFIG_OF
) && dev
&& dev
->of_node
)
740 return of_pwm_get(dev
->of_node
, con_id
);
743 * We look up the provider in the static table typically provided by
744 * board setup code. We first try to lookup the consumer device by
745 * name. If the consumer device was passed in as NULL or if no match
746 * was found, we try to find the consumer by directly looking it up
749 * If a match is found, the provider PWM chip is looked up by name
750 * and a PWM device is requested using the PWM device per-chip index.
752 * The lookup algorithm was shamelessly taken from the clock
755 * We do slightly fuzzy matching here:
756 * An entry with a NULL ID is assumed to be a wildcard.
757 * If an entry has a device ID, it must match
758 * If an entry has a connection ID, it must match
759 * Then we take the most specific entry - with the following order
760 * of precedence: dev+con > dev only > con only.
762 mutex_lock(&pwm_lookup_lock
);
764 list_for_each_entry(p
, &pwm_lookup_list
, list
) {
768 if (!dev_id
|| strcmp(p
->dev_id
, dev_id
))
775 if (!con_id
|| strcmp(p
->con_id
, con_id
))
792 pwm
= ERR_PTR(-ENODEV
);
796 chip
= pwmchip_find_by_name(chosen
->provider
);
800 pwm
= pwm_request_from_chip(chip
, chosen
->index
, con_id
?: dev_id
);
804 pwm
->args
.period
= chosen
->period
;
805 pwm
->args
.polarity
= chosen
->polarity
;
808 mutex_unlock(&pwm_lookup_lock
);
811 EXPORT_SYMBOL_GPL(pwm_get
);
814 * pwm_put() - release a PWM device
817 void pwm_put(struct pwm_device
*pwm
)
822 mutex_lock(&pwm_lock
);
824 if (!test_and_clear_bit(PWMF_REQUESTED
, &pwm
->flags
)) {
825 pr_warn("PWM device already freed\n");
829 if (pwm
->chip
->ops
->free
)
830 pwm
->chip
->ops
->free(pwm
->chip
, pwm
);
834 module_put(pwm
->chip
->ops
->owner
);
836 mutex_unlock(&pwm_lock
);
838 EXPORT_SYMBOL_GPL(pwm_put
);
840 static void devm_pwm_release(struct device
*dev
, void *res
)
842 pwm_put(*(struct pwm_device
**)res
);
846 * devm_pwm_get() - resource managed pwm_get()
847 * @dev: device for PWM consumer
848 * @con_id: consumer name
850 * This function performs like pwm_get() but the acquired PWM device will
851 * automatically be released on driver detach.
853 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
854 * error code on failure.
856 struct pwm_device
*devm_pwm_get(struct device
*dev
, const char *con_id
)
858 struct pwm_device
**ptr
, *pwm
;
860 ptr
= devres_alloc(devm_pwm_release
, sizeof(*ptr
), GFP_KERNEL
);
862 return ERR_PTR(-ENOMEM
);
864 pwm
= pwm_get(dev
, con_id
);
867 devres_add(dev
, ptr
);
874 EXPORT_SYMBOL_GPL(devm_pwm_get
);
877 * devm_of_pwm_get() - resource managed of_pwm_get()
878 * @dev: device for PWM consumer
879 * @np: device node to get the PWM from
880 * @con_id: consumer name
882 * This function performs like of_pwm_get() but the acquired PWM device will
883 * automatically be released on driver detach.
885 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
886 * error code on failure.
888 struct pwm_device
*devm_of_pwm_get(struct device
*dev
, struct device_node
*np
,
891 struct pwm_device
**ptr
, *pwm
;
893 ptr
= devres_alloc(devm_pwm_release
, sizeof(*ptr
), GFP_KERNEL
);
895 return ERR_PTR(-ENOMEM
);
897 pwm
= of_pwm_get(np
, con_id
);
900 devres_add(dev
, ptr
);
907 EXPORT_SYMBOL_GPL(devm_of_pwm_get
);
909 static int devm_pwm_match(struct device
*dev
, void *res
, void *data
)
911 struct pwm_device
**p
= res
;
913 if (WARN_ON(!p
|| !*p
))
920 * devm_pwm_put() - resource managed pwm_put()
921 * @dev: device for PWM consumer
924 * Release a PWM previously allocated using devm_pwm_get(). Calling this
925 * function is usually not needed because devm-allocated resources are
926 * automatically released on driver detach.
928 void devm_pwm_put(struct device
*dev
, struct pwm_device
*pwm
)
930 WARN_ON(devres_release(dev
, devm_pwm_release
, devm_pwm_match
, pwm
));
932 EXPORT_SYMBOL_GPL(devm_pwm_put
);
935 * pwm_can_sleep() - report whether PWM access will sleep
938 * Returns: True if accessing the PWM can sleep, false otherwise.
940 bool pwm_can_sleep(struct pwm_device
*pwm
)
944 EXPORT_SYMBOL_GPL(pwm_can_sleep
);
946 #ifdef CONFIG_DEBUG_FS
947 static void pwm_dbg_show(struct pwm_chip
*chip
, struct seq_file
*s
)
951 for (i
= 0; i
< chip
->npwm
; i
++) {
952 struct pwm_device
*pwm
= &chip
->pwms
[i
];
953 struct pwm_state state
;
955 pwm_get_state(pwm
, &state
);
957 seq_printf(s
, " pwm-%-3d (%-20.20s):", i
, pwm
->label
);
959 if (test_bit(PWMF_REQUESTED
, &pwm
->flags
))
960 seq_puts(s
, " requested");
963 seq_puts(s
, " enabled");
965 seq_printf(s
, " period: %u ns", state
.period
);
966 seq_printf(s
, " duty: %u ns", state
.duty_cycle
);
967 seq_printf(s
, " polarity: %s",
968 state
.polarity
? "inverse" : "normal");
974 static void *pwm_seq_start(struct seq_file
*s
, loff_t
*pos
)
976 mutex_lock(&pwm_lock
);
979 return seq_list_start(&pwm_chips
, *pos
);
982 static void *pwm_seq_next(struct seq_file
*s
, void *v
, loff_t
*pos
)
986 return seq_list_next(v
, &pwm_chips
, pos
);
989 static void pwm_seq_stop(struct seq_file
*s
, void *v
)
991 mutex_unlock(&pwm_lock
);
994 static int pwm_seq_show(struct seq_file
*s
, void *v
)
996 struct pwm_chip
*chip
= list_entry(v
, struct pwm_chip
, list
);
998 seq_printf(s
, "%s%s/%s, %d PWM device%s\n", (char *)s
->private,
999 chip
->dev
->bus
? chip
->dev
->bus
->name
: "no-bus",
1000 dev_name(chip
->dev
), chip
->npwm
,
1001 (chip
->npwm
!= 1) ? "s" : "");
1003 if (chip
->ops
->dbg_show
)
1004 chip
->ops
->dbg_show(chip
, s
);
1006 pwm_dbg_show(chip
, s
);
1011 static const struct seq_operations pwm_seq_ops
= {
1012 .start
= pwm_seq_start
,
1013 .next
= pwm_seq_next
,
1014 .stop
= pwm_seq_stop
,
1015 .show
= pwm_seq_show
,
1018 static int pwm_seq_open(struct inode
*inode
, struct file
*file
)
1020 return seq_open(file
, &pwm_seq_ops
);
1023 static const struct file_operations pwm_debugfs_ops
= {
1024 .owner
= THIS_MODULE
,
1025 .open
= pwm_seq_open
,
1027 .llseek
= seq_lseek
,
1028 .release
= seq_release
,
1031 static int __init
pwm_debugfs_init(void)
1033 debugfs_create_file("pwm", S_IFREG
| S_IRUGO
, NULL
, NULL
,
1038 subsys_initcall(pwm_debugfs_init
);
1039 #endif /* CONFIG_DEBUG_FS */