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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic pwmlib implementation
4 *
5 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
6 * Copyright (C) 2011-2012 Avionic Design GmbH
7 */
8
9#include <linux/acpi.h>
10#include <linux/module.h>
11#include <linux/pwm.h>
12#include <linux/radix-tree.h>
13#include <linux/list.h>
14#include <linux/mutex.h>
15#include <linux/err.h>
16#include <linux/slab.h>
17#include <linux/device.h>
18#include <linux/debugfs.h>
19#include <linux/seq_file.h>
20
21#include <dt-bindings/pwm/pwm.h>
22
23#define CREATE_TRACE_POINTS
24#include <trace/events/pwm.h>
25
26#define MAX_PWMS 1024
27
28static DEFINE_MUTEX(pwm_lookup_lock);
29static LIST_HEAD(pwm_lookup_list);
30static DEFINE_MUTEX(pwm_lock);
31static LIST_HEAD(pwm_chips);
32static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
33static RADIX_TREE(pwm_tree, GFP_KERNEL);
34
35static struct pwm_device *pwm_to_device(unsigned int pwm)
36{
37 return radix_tree_lookup(&pwm_tree, pwm);
38}
39
40static int alloc_pwms(int pwm, unsigned int count)
41{
42 unsigned int from = 0;
43 unsigned int start;
44
45 if (pwm >= MAX_PWMS)
46 return -EINVAL;
47
48 if (pwm >= 0)
49 from = pwm;
50
51 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
52 count, 0);
53
54 if (pwm >= 0 && start != pwm)
55 return -EEXIST;
56
57 if (start + count > MAX_PWMS)
58 return -ENOSPC;
59
60 return start;
61}
62
63static void free_pwms(struct pwm_chip *chip)
64{
65 unsigned int i;
66
67 for (i = 0; i < chip->npwm; i++) {
68 struct pwm_device *pwm = &chip->pwms[i];
69
70 radix_tree_delete(&pwm_tree, pwm->pwm);
71 }
72
73 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
74
75 kfree(chip->pwms);
76 chip->pwms = NULL;
77}
78
79static struct pwm_chip *pwmchip_find_by_name(const char *name)
80{
81 struct pwm_chip *chip;
82
83 if (!name)
84 return NULL;
85
86 mutex_lock(&pwm_lock);
87
88 list_for_each_entry(chip, &pwm_chips, list) {
89 const char *chip_name = dev_name(chip->dev);
90
91 if (chip_name && strcmp(chip_name, name) == 0) {
92 mutex_unlock(&pwm_lock);
93 return chip;
94 }
95 }
96
97 mutex_unlock(&pwm_lock);
98
99 return NULL;
100}
101
102static int pwm_device_request(struct pwm_device *pwm, const char *label)
103{
104 int err;
105
106 if (test_bit(PWMF_REQUESTED, &pwm->flags))
107 return -EBUSY;
108
109 if (!try_module_get(pwm->chip->ops->owner))
110 return -ENODEV;
111
112 if (pwm->chip->ops->request) {
113 err = pwm->chip->ops->request(pwm->chip, pwm);
114 if (err) {
115 module_put(pwm->chip->ops->owner);
116 return err;
117 }
118 }
119
120 if (pwm->chip->ops->get_state) {
121 pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
122 trace_pwm_get(pwm, &pwm->state);
123
124 if (IS_ENABLED(CONFIG_PWM_DEBUG))
125 pwm->last = pwm->state;
126 }
127
128 set_bit(PWMF_REQUESTED, &pwm->flags);
129 pwm->label = label;
130
131 return 0;
132}
133
134struct pwm_device *
135of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
136{
137 struct pwm_device *pwm;
138
139 /* check, whether the driver supports a third cell for flags */
140 if (pc->of_pwm_n_cells < 3)
141 return ERR_PTR(-EINVAL);
142
143 /* flags in the third cell are optional */
144 if (args->args_count < 2)
145 return ERR_PTR(-EINVAL);
146
147 if (args->args[0] >= pc->npwm)
148 return ERR_PTR(-EINVAL);
149
150 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
151 if (IS_ERR(pwm))
152 return pwm;
153
154 pwm->args.period = args->args[1];
155 pwm->args.polarity = PWM_POLARITY_NORMAL;
156
157 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
158 pwm->args.polarity = PWM_POLARITY_INVERSED;
159
160 return pwm;
161}
162EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
163
164static struct pwm_device *
165of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
166{
167 struct pwm_device *pwm;
168
169 /* sanity check driver support */
170 if (pc->of_pwm_n_cells < 2)
171 return ERR_PTR(-EINVAL);
172
173 /* all cells are required */
174 if (args->args_count != pc->of_pwm_n_cells)
175 return ERR_PTR(-EINVAL);
176
177 if (args->args[0] >= pc->npwm)
178 return ERR_PTR(-EINVAL);
179
180 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
181 if (IS_ERR(pwm))
182 return pwm;
183
184 pwm->args.period = args->args[1];
185
186 return pwm;
187}
188
189static void of_pwmchip_add(struct pwm_chip *chip)
190{
191 if (!chip->dev || !chip->dev->of_node)
192 return;
193
194 if (!chip->of_xlate) {
195 chip->of_xlate = of_pwm_simple_xlate;
196 chip->of_pwm_n_cells = 2;
197 }
198
199 of_node_get(chip->dev->of_node);
200}
201
202static void of_pwmchip_remove(struct pwm_chip *chip)
203{
204 if (chip->dev)
205 of_node_put(chip->dev->of_node);
206}
207
208/**
209 * pwm_set_chip_data() - set private chip data for a PWM
210 * @pwm: PWM device
211 * @data: pointer to chip-specific data
212 *
213 * Returns: 0 on success or a negative error code on failure.
214 */
215int pwm_set_chip_data(struct pwm_device *pwm, void *data)
216{
217 if (!pwm)
218 return -EINVAL;
219
220 pwm->chip_data = data;
221
222 return 0;
223}
224EXPORT_SYMBOL_GPL(pwm_set_chip_data);
225
226/**
227 * pwm_get_chip_data() - get private chip data for a PWM
228 * @pwm: PWM device
229 *
230 * Returns: A pointer to the chip-private data for the PWM device.
231 */
232void *pwm_get_chip_data(struct pwm_device *pwm)
233{
234 return pwm ? pwm->chip_data : NULL;
235}
236EXPORT_SYMBOL_GPL(pwm_get_chip_data);
237
238static bool pwm_ops_check(const struct pwm_chip *chip)
239{
240
241 const struct pwm_ops *ops = chip->ops;
242
243 /* driver supports legacy, non-atomic operation */
244 if (ops->config && ops->enable && ops->disable) {
245 if (IS_ENABLED(CONFIG_PWM_DEBUG))
246 dev_warn(chip->dev,
247 "Driver needs updating to atomic API\n");
248
249 return true;
250 }
251
252 if (!ops->apply)
253 return false;
254
255 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
256 dev_warn(chip->dev,
257 "Please implement the .get_state() callback\n");
258
259 return true;
260}
261
262/**
263 * pwmchip_add_with_polarity() - register a new PWM chip
264 * @chip: the PWM chip to add
265 * @polarity: initial polarity of PWM channels
266 *
267 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
268 * will be used. The initial polarity for all channels is specified by the
269 * @polarity parameter.
270 *
271 * Returns: 0 on success or a negative error code on failure.
272 */
273int pwmchip_add_with_polarity(struct pwm_chip *chip,
274 enum pwm_polarity polarity)
275{
276 struct pwm_device *pwm;
277 unsigned int i;
278 int ret;
279
280 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
281 return -EINVAL;
282
283 if (!pwm_ops_check(chip))
284 return -EINVAL;
285
286 mutex_lock(&pwm_lock);
287
288 ret = alloc_pwms(chip->base, chip->npwm);
289 if (ret < 0)
290 goto out;
291
292 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
293 if (!chip->pwms) {
294 ret = -ENOMEM;
295 goto out;
296 }
297
298 chip->base = ret;
299
300 for (i = 0; i < chip->npwm; i++) {
301 pwm = &chip->pwms[i];
302
303 pwm->chip = chip;
304 pwm->pwm = chip->base + i;
305 pwm->hwpwm = i;
306 pwm->state.polarity = polarity;
307
308 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
309 }
310
311 bitmap_set(allocated_pwms, chip->base, chip->npwm);
312
313 INIT_LIST_HEAD(&chip->list);
314 list_add(&chip->list, &pwm_chips);
315
316 ret = 0;
317
318 if (IS_ENABLED(CONFIG_OF))
319 of_pwmchip_add(chip);
320
321out:
322 mutex_unlock(&pwm_lock);
323
324 if (!ret)
325 pwmchip_sysfs_export(chip);
326
327 return ret;
328}
329EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
330
331/**
332 * pwmchip_add() - register a new PWM chip
333 * @chip: the PWM chip to add
334 *
335 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
336 * will be used. The initial polarity for all channels is normal.
337 *
338 * Returns: 0 on success or a negative error code on failure.
339 */
340int pwmchip_add(struct pwm_chip *chip)
341{
342 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
343}
344EXPORT_SYMBOL_GPL(pwmchip_add);
345
346/**
347 * pwmchip_remove() - remove a PWM chip
348 * @chip: the PWM chip to remove
349 *
350 * Removes a PWM chip. This function may return busy if the PWM chip provides
351 * a PWM device that is still requested.
352 *
353 * Returns: 0 on success or a negative error code on failure.
354 */
355int pwmchip_remove(struct pwm_chip *chip)
356{
357 unsigned int i;
358 int ret = 0;
359
360 pwmchip_sysfs_unexport(chip);
361
362 mutex_lock(&pwm_lock);
363
364 for (i = 0; i < chip->npwm; i++) {
365 struct pwm_device *pwm = &chip->pwms[i];
366
367 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
368 ret = -EBUSY;
369 goto out;
370 }
371 }
372
373 list_del_init(&chip->list);
374
375 if (IS_ENABLED(CONFIG_OF))
376 of_pwmchip_remove(chip);
377
378 free_pwms(chip);
379
380out:
381 mutex_unlock(&pwm_lock);
382 return ret;
383}
384EXPORT_SYMBOL_GPL(pwmchip_remove);
385
386/**
387 * pwm_request() - request a PWM device
388 * @pwm: global PWM device index
389 * @label: PWM device label
390 *
391 * This function is deprecated, use pwm_get() instead.
392 *
393 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
394 * failure.
395 */
396struct pwm_device *pwm_request(int pwm, const char *label)
397{
398 struct pwm_device *dev;
399 int err;
400
401 if (pwm < 0 || pwm >= MAX_PWMS)
402 return ERR_PTR(-EINVAL);
403
404 mutex_lock(&pwm_lock);
405
406 dev = pwm_to_device(pwm);
407 if (!dev) {
408 dev = ERR_PTR(-EPROBE_DEFER);
409 goto out;
410 }
411
412 err = pwm_device_request(dev, label);
413 if (err < 0)
414 dev = ERR_PTR(err);
415
416out:
417 mutex_unlock(&pwm_lock);
418
419 return dev;
420}
421EXPORT_SYMBOL_GPL(pwm_request);
422
423/**
424 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
425 * @chip: PWM chip
426 * @index: per-chip index of the PWM to request
427 * @label: a literal description string of this PWM
428 *
429 * Returns: A pointer to the PWM device at the given index of the given PWM
430 * chip. A negative error code is returned if the index is not valid for the
431 * specified PWM chip or if the PWM device cannot be requested.
432 */
433struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
434 unsigned int index,
435 const char *label)
436{
437 struct pwm_device *pwm;
438 int err;
439
440 if (!chip || index >= chip->npwm)
441 return ERR_PTR(-EINVAL);
442
443 mutex_lock(&pwm_lock);
444 pwm = &chip->pwms[index];
445
446 err = pwm_device_request(pwm, label);
447 if (err < 0)
448 pwm = ERR_PTR(err);
449
450 mutex_unlock(&pwm_lock);
451 return pwm;
452}
453EXPORT_SYMBOL_GPL(pwm_request_from_chip);
454
455/**
456 * pwm_free() - free a PWM device
457 * @pwm: PWM device
458 *
459 * This function is deprecated, use pwm_put() instead.
460 */
461void pwm_free(struct pwm_device *pwm)
462{
463 pwm_put(pwm);
464}
465EXPORT_SYMBOL_GPL(pwm_free);
466
467static void pwm_apply_state_debug(struct pwm_device *pwm,
468 const struct pwm_state *state)
469{
470 struct pwm_state *last = &pwm->last;
471 struct pwm_chip *chip = pwm->chip;
472 struct pwm_state s1, s2;
473 int err;
474
475 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
476 return;
477
478 /* No reasonable diagnosis possible without .get_state() */
479 if (!chip->ops->get_state)
480 return;
481
482 /*
483 * *state was just applied. Read out the hardware state and do some
484 * checks.
485 */
486
487 chip->ops->get_state(chip, pwm, &s1);
488 trace_pwm_get(pwm, &s1);
489
490 /*
491 * The lowlevel driver either ignored .polarity (which is a bug) or as
492 * best effort inverted .polarity and fixed .duty_cycle respectively.
493 * Undo this inversion and fixup for further tests.
494 */
495 if (s1.enabled && s1.polarity != state->polarity) {
496 s2.polarity = state->polarity;
497 s2.duty_cycle = s1.period - s1.duty_cycle;
498 s2.period = s1.period;
499 s2.enabled = s1.enabled;
500 } else {
501 s2 = s1;
502 }
503
504 if (s2.polarity != state->polarity &&
505 state->duty_cycle < state->period)
506 dev_warn(chip->dev, ".apply ignored .polarity\n");
507
508 if (state->enabled &&
509 last->polarity == state->polarity &&
510 last->period > s2.period &&
511 last->period <= state->period)
512 dev_warn(chip->dev,
513 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
514 state->period, s2.period, last->period);
515
516 if (state->enabled && state->period < s2.period)
517 dev_warn(chip->dev,
518 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
519 state->period, s2.period);
520
521 if (state->enabled &&
522 last->polarity == state->polarity &&
523 last->period == s2.period &&
524 last->duty_cycle > s2.duty_cycle &&
525 last->duty_cycle <= state->duty_cycle)
526 dev_warn(chip->dev,
527 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
528 state->duty_cycle, state->period,
529 s2.duty_cycle, s2.period,
530 last->duty_cycle, last->period);
531
532 if (state->enabled && state->duty_cycle < s2.duty_cycle)
533 dev_warn(chip->dev,
534 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
535 state->duty_cycle, state->period,
536 s2.duty_cycle, s2.period);
537
538 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
539 dev_warn(chip->dev,
540 "requested disabled, but yielded enabled with duty > 0\n");
541
542 /* reapply the state that the driver reported being configured. */
543 err = chip->ops->apply(chip, pwm, &s1);
544 if (err) {
545 *last = s1;
546 dev_err(chip->dev, "failed to reapply current setting\n");
547 return;
548 }
549
550 trace_pwm_apply(pwm, &s1);
551
552 chip->ops->get_state(chip, pwm, last);
553 trace_pwm_get(pwm, last);
554
555 /* reapplication of the current state should give an exact match */
556 if (s1.enabled != last->enabled ||
557 s1.polarity != last->polarity ||
558 (s1.enabled && s1.period != last->period) ||
559 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
560 dev_err(chip->dev,
561 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
562 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
563 last->enabled, last->polarity, last->duty_cycle,
564 last->period);
565 }
566}
567
568/**
569 * pwm_apply_state() - atomically apply a new state to a PWM device
570 * @pwm: PWM device
571 * @state: new state to apply
572 */
573int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
574{
575 struct pwm_chip *chip;
576 int err;
577
578 if (!pwm || !state || !state->period ||
579 state->duty_cycle > state->period)
580 return -EINVAL;
581
582 chip = pwm->chip;
583
584 if (state->period == pwm->state.period &&
585 state->duty_cycle == pwm->state.duty_cycle &&
586 state->polarity == pwm->state.polarity &&
587 state->enabled == pwm->state.enabled)
588 return 0;
589
590 if (chip->ops->apply) {
591 err = chip->ops->apply(chip, pwm, state);
592 if (err)
593 return err;
594
595 trace_pwm_apply(pwm, state);
596
597 pwm->state = *state;
598
599 /*
600 * only do this after pwm->state was applied as some
601 * implementations of .get_state depend on this
602 */
603 pwm_apply_state_debug(pwm, state);
604 } else {
605 /*
606 * FIXME: restore the initial state in case of error.
607 */
608 if (state->polarity != pwm->state.polarity) {
609 if (!chip->ops->set_polarity)
610 return -ENOTSUPP;
611
612 /*
613 * Changing the polarity of a running PWM is
614 * only allowed when the PWM driver implements
615 * ->apply().
616 */
617 if (pwm->state.enabled) {
618 chip->ops->disable(chip, pwm);
619 pwm->state.enabled = false;
620 }
621
622 err = chip->ops->set_polarity(chip, pwm,
623 state->polarity);
624 if (err)
625 return err;
626
627 pwm->state.polarity = state->polarity;
628 }
629
630 if (state->period != pwm->state.period ||
631 state->duty_cycle != pwm->state.duty_cycle) {
632 err = chip->ops->config(pwm->chip, pwm,
633 state->duty_cycle,
634 state->period);
635 if (err)
636 return err;
637
638 pwm->state.duty_cycle = state->duty_cycle;
639 pwm->state.period = state->period;
640 }
641
642 if (state->enabled != pwm->state.enabled) {
643 if (state->enabled) {
644 err = chip->ops->enable(chip, pwm);
645 if (err)
646 return err;
647 } else {
648 chip->ops->disable(chip, pwm);
649 }
650
651 pwm->state.enabled = state->enabled;
652 }
653 }
654
655 return 0;
656}
657EXPORT_SYMBOL_GPL(pwm_apply_state);
658
659/**
660 * pwm_capture() - capture and report a PWM signal
661 * @pwm: PWM device
662 * @result: structure to fill with capture result
663 * @timeout: time to wait, in milliseconds, before giving up on capture
664 *
665 * Returns: 0 on success or a negative error code on failure.
666 */
667int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
668 unsigned long timeout)
669{
670 int err;
671
672 if (!pwm || !pwm->chip->ops)
673 return -EINVAL;
674
675 if (!pwm->chip->ops->capture)
676 return -ENOSYS;
677
678 mutex_lock(&pwm_lock);
679 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
680 mutex_unlock(&pwm_lock);
681
682 return err;
683}
684EXPORT_SYMBOL_GPL(pwm_capture);
685
686/**
687 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
688 * @pwm: PWM device
689 *
690 * This function will adjust the PWM config to the PWM arguments provided
691 * by the DT or PWM lookup table. This is particularly useful to adapt
692 * the bootloader config to the Linux one.
693 */
694int pwm_adjust_config(struct pwm_device *pwm)
695{
696 struct pwm_state state;
697 struct pwm_args pargs;
698
699 pwm_get_args(pwm, &pargs);
700 pwm_get_state(pwm, &state);
701
702 /*
703 * If the current period is zero it means that either the PWM driver
704 * does not support initial state retrieval or the PWM has not yet
705 * been configured.
706 *
707 * In either case, we setup the new period and polarity, and assign a
708 * duty cycle of 0.
709 */
710 if (!state.period) {
711 state.duty_cycle = 0;
712 state.period = pargs.period;
713 state.polarity = pargs.polarity;
714
715 return pwm_apply_state(pwm, &state);
716 }
717
718 /*
719 * Adjust the PWM duty cycle/period based on the period value provided
720 * in PWM args.
721 */
722 if (pargs.period != state.period) {
723 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
724
725 do_div(dutycycle, state.period);
726 state.duty_cycle = dutycycle;
727 state.period = pargs.period;
728 }
729
730 /*
731 * If the polarity changed, we should also change the duty cycle.
732 */
733 if (pargs.polarity != state.polarity) {
734 state.polarity = pargs.polarity;
735 state.duty_cycle = state.period - state.duty_cycle;
736 }
737
738 return pwm_apply_state(pwm, &state);
739}
740EXPORT_SYMBOL_GPL(pwm_adjust_config);
741
742static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
743{
744 struct pwm_chip *chip;
745
746 mutex_lock(&pwm_lock);
747
748 list_for_each_entry(chip, &pwm_chips, list)
749 if (chip->dev && chip->dev->of_node == np) {
750 mutex_unlock(&pwm_lock);
751 return chip;
752 }
753
754 mutex_unlock(&pwm_lock);
755
756 return ERR_PTR(-EPROBE_DEFER);
757}
758
759static struct device_link *pwm_device_link_add(struct device *dev,
760 struct pwm_device *pwm)
761{
762 struct device_link *dl;
763
764 if (!dev) {
765 /*
766 * No device for the PWM consumer has been provided. It may
767 * impact the PM sequence ordering: the PWM supplier may get
768 * suspended before the consumer.
769 */
770 dev_warn(pwm->chip->dev,
771 "No consumer device specified to create a link to\n");
772 return NULL;
773 }
774
775 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
776 if (!dl) {
777 dev_err(dev, "failed to create device link to %s\n",
778 dev_name(pwm->chip->dev));
779 return ERR_PTR(-EINVAL);
780 }
781
782 return dl;
783}
784
785/**
786 * of_pwm_get() - request a PWM via the PWM framework
787 * @dev: device for PWM consumer
788 * @np: device node to get the PWM from
789 * @con_id: consumer name
790 *
791 * Returns the PWM device parsed from the phandle and index specified in the
792 * "pwms" property of a device tree node or a negative error-code on failure.
793 * Values parsed from the device tree are stored in the returned PWM device
794 * object.
795 *
796 * If con_id is NULL, the first PWM device listed in the "pwms" property will
797 * be requested. Otherwise the "pwm-names" property is used to do a reverse
798 * lookup of the PWM index. This also means that the "pwm-names" property
799 * becomes mandatory for devices that look up the PWM device via the con_id
800 * parameter.
801 *
802 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
803 * error code on failure.
804 */
805struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
806 const char *con_id)
807{
808 struct pwm_device *pwm = NULL;
809 struct of_phandle_args args;
810 struct device_link *dl;
811 struct pwm_chip *pc;
812 int index = 0;
813 int err;
814
815 if (con_id) {
816 index = of_property_match_string(np, "pwm-names", con_id);
817 if (index < 0)
818 return ERR_PTR(index);
819 }
820
821 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
822 &args);
823 if (err) {
824 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
825 return ERR_PTR(err);
826 }
827
828 pc = of_node_to_pwmchip(args.np);
829 if (IS_ERR(pc)) {
830 if (PTR_ERR(pc) != -EPROBE_DEFER)
831 pr_err("%s(): PWM chip not found\n", __func__);
832
833 pwm = ERR_CAST(pc);
834 goto put;
835 }
836
837 pwm = pc->of_xlate(pc, &args);
838 if (IS_ERR(pwm))
839 goto put;
840
841 dl = pwm_device_link_add(dev, pwm);
842 if (IS_ERR(dl)) {
843 /* of_xlate ended up calling pwm_request_from_chip() */
844 pwm_free(pwm);
845 pwm = ERR_CAST(dl);
846 goto put;
847 }
848
849 /*
850 * If a consumer name was not given, try to look it up from the
851 * "pwm-names" property if it exists. Otherwise use the name of
852 * the user device node.
853 */
854 if (!con_id) {
855 err = of_property_read_string_index(np, "pwm-names", index,
856 &con_id);
857 if (err < 0)
858 con_id = np->name;
859 }
860
861 pwm->label = con_id;
862
863put:
864 of_node_put(args.np);
865
866 return pwm;
867}
868EXPORT_SYMBOL_GPL(of_pwm_get);
869
870#if IS_ENABLED(CONFIG_ACPI)
871static struct pwm_chip *device_to_pwmchip(struct device *dev)
872{
873 struct pwm_chip *chip;
874
875 mutex_lock(&pwm_lock);
876
877 list_for_each_entry(chip, &pwm_chips, list) {
878 struct acpi_device *adev = ACPI_COMPANION(chip->dev);
879
880 if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
881 mutex_unlock(&pwm_lock);
882 return chip;
883 }
884 }
885
886 mutex_unlock(&pwm_lock);
887
888 return ERR_PTR(-EPROBE_DEFER);
889}
890#endif
891
892/**
893 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
894 * @fwnode: firmware node to get the "pwm" property from
895 *
896 * Returns the PWM device parsed from the fwnode and index specified in the
897 * "pwms" property or a negative error-code on failure.
898 * Values parsed from the device tree are stored in the returned PWM device
899 * object.
900 *
901 * This is analogous to of_pwm_get() except con_id is not yet supported.
902 * ACPI entries must look like
903 * Package () {"pwms", Package ()
904 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
905 *
906 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
907 * error code on failure.
908 */
909static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
910{
911 struct pwm_device *pwm = ERR_PTR(-ENODEV);
912#if IS_ENABLED(CONFIG_ACPI)
913 struct fwnode_reference_args args;
914 struct acpi_device *acpi;
915 struct pwm_chip *chip;
916 int ret;
917
918 memset(&args, 0, sizeof(args));
919
920 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
921 if (ret < 0)
922 return ERR_PTR(ret);
923
924 acpi = to_acpi_device_node(args.fwnode);
925 if (!acpi)
926 return ERR_PTR(-EINVAL);
927
928 if (args.nargs < 2)
929 return ERR_PTR(-EPROTO);
930
931 chip = device_to_pwmchip(&acpi->dev);
932 if (IS_ERR(chip))
933 return ERR_CAST(chip);
934
935 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
936 if (IS_ERR(pwm))
937 return pwm;
938
939 pwm->args.period = args.args[1];
940 pwm->args.polarity = PWM_POLARITY_NORMAL;
941
942 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
943 pwm->args.polarity = PWM_POLARITY_INVERSED;
944#endif
945
946 return pwm;
947}
948
949/**
950 * pwm_add_table() - register PWM device consumers
951 * @table: array of consumers to register
952 * @num: number of consumers in table
953 */
954void pwm_add_table(struct pwm_lookup *table, size_t num)
955{
956 mutex_lock(&pwm_lookup_lock);
957
958 while (num--) {
959 list_add_tail(&table->list, &pwm_lookup_list);
960 table++;
961 }
962
963 mutex_unlock(&pwm_lookup_lock);
964}
965
966/**
967 * pwm_remove_table() - unregister PWM device consumers
968 * @table: array of consumers to unregister
969 * @num: number of consumers in table
970 */
971void pwm_remove_table(struct pwm_lookup *table, size_t num)
972{
973 mutex_lock(&pwm_lookup_lock);
974
975 while (num--) {
976 list_del(&table->list);
977 table++;
978 }
979
980 mutex_unlock(&pwm_lookup_lock);
981}
982
983/**
984 * pwm_get() - look up and request a PWM device
985 * @dev: device for PWM consumer
986 * @con_id: consumer name
987 *
988 * Lookup is first attempted using DT. If the device was not instantiated from
989 * a device tree, a PWM chip and a relative index is looked up via a table
990 * supplied by board setup code (see pwm_add_table()).
991 *
992 * Once a PWM chip has been found the specified PWM device will be requested
993 * and is ready to be used.
994 *
995 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
996 * error code on failure.
997 */
998struct pwm_device *pwm_get(struct device *dev, const char *con_id)
999{
1000 const char *dev_id = dev ? dev_name(dev) : NULL;
1001 struct pwm_device *pwm;
1002 struct pwm_chip *chip;
1003 struct device_link *dl;
1004 unsigned int best = 0;
1005 struct pwm_lookup *p, *chosen = NULL;
1006 unsigned int match;
1007 int err;
1008
1009 /* look up via DT first */
1010 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
1011 return of_pwm_get(dev, dev->of_node, con_id);
1012
1013 /* then lookup via ACPI */
1014 if (dev && is_acpi_node(dev->fwnode)) {
1015 pwm = acpi_pwm_get(dev->fwnode);
1016 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
1017 return pwm;
1018 }
1019
1020 /*
1021 * We look up the provider in the static table typically provided by
1022 * board setup code. We first try to lookup the consumer device by
1023 * name. If the consumer device was passed in as NULL or if no match
1024 * was found, we try to find the consumer by directly looking it up
1025 * by name.
1026 *
1027 * If a match is found, the provider PWM chip is looked up by name
1028 * and a PWM device is requested using the PWM device per-chip index.
1029 *
1030 * The lookup algorithm was shamelessly taken from the clock
1031 * framework:
1032 *
1033 * We do slightly fuzzy matching here:
1034 * An entry with a NULL ID is assumed to be a wildcard.
1035 * If an entry has a device ID, it must match
1036 * If an entry has a connection ID, it must match
1037 * Then we take the most specific entry - with the following order
1038 * of precedence: dev+con > dev only > con only.
1039 */
1040 mutex_lock(&pwm_lookup_lock);
1041
1042 list_for_each_entry(p, &pwm_lookup_list, list) {
1043 match = 0;
1044
1045 if (p->dev_id) {
1046 if (!dev_id || strcmp(p->dev_id, dev_id))
1047 continue;
1048
1049 match += 2;
1050 }
1051
1052 if (p->con_id) {
1053 if (!con_id || strcmp(p->con_id, con_id))
1054 continue;
1055
1056 match += 1;
1057 }
1058
1059 if (match > best) {
1060 chosen = p;
1061
1062 if (match != 3)
1063 best = match;
1064 else
1065 break;
1066 }
1067 }
1068
1069 mutex_unlock(&pwm_lookup_lock);
1070
1071 if (!chosen)
1072 return ERR_PTR(-ENODEV);
1073
1074 chip = pwmchip_find_by_name(chosen->provider);
1075
1076 /*
1077 * If the lookup entry specifies a module, load the module and retry
1078 * the PWM chip lookup. This can be used to work around driver load
1079 * ordering issues if driver's can't be made to properly support the
1080 * deferred probe mechanism.
1081 */
1082 if (!chip && chosen->module) {
1083 err = request_module(chosen->module);
1084 if (err == 0)
1085 chip = pwmchip_find_by_name(chosen->provider);
1086 }
1087
1088 if (!chip)
1089 return ERR_PTR(-EPROBE_DEFER);
1090
1091 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1092 if (IS_ERR(pwm))
1093 return pwm;
1094
1095 dl = pwm_device_link_add(dev, pwm);
1096 if (IS_ERR(dl)) {
1097 pwm_free(pwm);
1098 return ERR_CAST(dl);
1099 }
1100
1101 pwm->args.period = chosen->period;
1102 pwm->args.polarity = chosen->polarity;
1103
1104 return pwm;
1105}
1106EXPORT_SYMBOL_GPL(pwm_get);
1107
1108/**
1109 * pwm_put() - release a PWM device
1110 * @pwm: PWM device
1111 */
1112void pwm_put(struct pwm_device *pwm)
1113{
1114 if (!pwm)
1115 return;
1116
1117 mutex_lock(&pwm_lock);
1118
1119 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1120 pr_warn("PWM device already freed\n");
1121 goto out;
1122 }
1123
1124 if (pwm->chip->ops->free)
1125 pwm->chip->ops->free(pwm->chip, pwm);
1126
1127 pwm_set_chip_data(pwm, NULL);
1128 pwm->label = NULL;
1129
1130 module_put(pwm->chip->ops->owner);
1131out:
1132 mutex_unlock(&pwm_lock);
1133}
1134EXPORT_SYMBOL_GPL(pwm_put);
1135
1136static void devm_pwm_release(struct device *dev, void *res)
1137{
1138 pwm_put(*(struct pwm_device **)res);
1139}
1140
1141/**
1142 * devm_pwm_get() - resource managed pwm_get()
1143 * @dev: device for PWM consumer
1144 * @con_id: consumer name
1145 *
1146 * This function performs like pwm_get() but the acquired PWM device will
1147 * automatically be released on driver detach.
1148 *
1149 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1150 * error code on failure.
1151 */
1152struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1153{
1154 struct pwm_device **ptr, *pwm;
1155
1156 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1157 if (!ptr)
1158 return ERR_PTR(-ENOMEM);
1159
1160 pwm = pwm_get(dev, con_id);
1161 if (!IS_ERR(pwm)) {
1162 *ptr = pwm;
1163 devres_add(dev, ptr);
1164 } else {
1165 devres_free(ptr);
1166 }
1167
1168 return pwm;
1169}
1170EXPORT_SYMBOL_GPL(devm_pwm_get);
1171
1172/**
1173 * devm_of_pwm_get() - resource managed of_pwm_get()
1174 * @dev: device for PWM consumer
1175 * @np: device node to get the PWM from
1176 * @con_id: consumer name
1177 *
1178 * This function performs like of_pwm_get() but the acquired PWM device will
1179 * automatically be released on driver detach.
1180 *
1181 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1182 * error code on failure.
1183 */
1184struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
1185 const char *con_id)
1186{
1187 struct pwm_device **ptr, *pwm;
1188
1189 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1190 if (!ptr)
1191 return ERR_PTR(-ENOMEM);
1192
1193 pwm = of_pwm_get(dev, np, con_id);
1194 if (!IS_ERR(pwm)) {
1195 *ptr = pwm;
1196 devres_add(dev, ptr);
1197 } else {
1198 devres_free(ptr);
1199 }
1200
1201 return pwm;
1202}
1203EXPORT_SYMBOL_GPL(devm_of_pwm_get);
1204
1205/**
1206 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1207 * @dev: device for PWM consumer
1208 * @fwnode: firmware node to get the PWM from
1209 * @con_id: consumer name
1210 *
1211 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1212 * acpi_pwm_get() for a detailed description.
1213 *
1214 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1215 * error code on failure.
1216 */
1217struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1218 struct fwnode_handle *fwnode,
1219 const char *con_id)
1220{
1221 struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV);
1222
1223 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1224 if (!ptr)
1225 return ERR_PTR(-ENOMEM);
1226
1227 if (is_of_node(fwnode))
1228 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1229 else if (is_acpi_node(fwnode))
1230 pwm = acpi_pwm_get(fwnode);
1231
1232 if (!IS_ERR(pwm)) {
1233 *ptr = pwm;
1234 devres_add(dev, ptr);
1235 } else {
1236 devres_free(ptr);
1237 }
1238
1239 return pwm;
1240}
1241EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1242
1243static int devm_pwm_match(struct device *dev, void *res, void *data)
1244{
1245 struct pwm_device **p = res;
1246
1247 if (WARN_ON(!p || !*p))
1248 return 0;
1249
1250 return *p == data;
1251}
1252
1253/**
1254 * devm_pwm_put() - resource managed pwm_put()
1255 * @dev: device for PWM consumer
1256 * @pwm: PWM device
1257 *
1258 * Release a PWM previously allocated using devm_pwm_get(). Calling this
1259 * function is usually not needed because devm-allocated resources are
1260 * automatically released on driver detach.
1261 */
1262void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
1263{
1264 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
1265}
1266EXPORT_SYMBOL_GPL(devm_pwm_put);
1267
1268#ifdef CONFIG_DEBUG_FS
1269static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1270{
1271 unsigned int i;
1272
1273 for (i = 0; i < chip->npwm; i++) {
1274 struct pwm_device *pwm = &chip->pwms[i];
1275 struct pwm_state state;
1276
1277 pwm_get_state(pwm, &state);
1278
1279 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1280
1281 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1282 seq_puts(s, " requested");
1283
1284 if (state.enabled)
1285 seq_puts(s, " enabled");
1286
1287 seq_printf(s, " period: %llu ns", state.period);
1288 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1289 seq_printf(s, " polarity: %s",
1290 state.polarity ? "inverse" : "normal");
1291
1292 seq_puts(s, "\n");
1293 }
1294}
1295
1296static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1297{
1298 mutex_lock(&pwm_lock);
1299 s->private = "";
1300
1301 return seq_list_start(&pwm_chips, *pos);
1302}
1303
1304static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1305{
1306 s->private = "\n";
1307
1308 return seq_list_next(v, &pwm_chips, pos);
1309}
1310
1311static void pwm_seq_stop(struct seq_file *s, void *v)
1312{
1313 mutex_unlock(&pwm_lock);
1314}
1315
1316static int pwm_seq_show(struct seq_file *s, void *v)
1317{
1318 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1319
1320 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1321 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1322 dev_name(chip->dev), chip->npwm,
1323 (chip->npwm != 1) ? "s" : "");
1324
1325 pwm_dbg_show(chip, s);
1326
1327 return 0;
1328}
1329
1330static const struct seq_operations pwm_seq_ops = {
1331 .start = pwm_seq_start,
1332 .next = pwm_seq_next,
1333 .stop = pwm_seq_stop,
1334 .show = pwm_seq_show,
1335};
1336
1337static int pwm_seq_open(struct inode *inode, struct file *file)
1338{
1339 return seq_open(file, &pwm_seq_ops);
1340}
1341
1342static const struct file_operations pwm_debugfs_ops = {
1343 .owner = THIS_MODULE,
1344 .open = pwm_seq_open,
1345 .read = seq_read,
1346 .llseek = seq_lseek,
1347 .release = seq_release,
1348};
1349
1350static int __init pwm_debugfs_init(void)
1351{
1352 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1353 &pwm_debugfs_ops);
1354
1355 return 0;
1356}
1357subsys_initcall(pwm_debugfs_init);
1358#endif /* CONFIG_DEBUG_FS */
1/*
2 * Generic pwmlib implementation
3 *
4 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
5 * Copyright (C) 2011-2012 Avionic Design GmbH
6 *
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)
10 * any later version.
11 *
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.
16 *
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.
20 */
21
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>
32
33#include <dt-bindings/pwm/pwm.h>
34
35#define MAX_PWMS 1024
36
37static DEFINE_MUTEX(pwm_lookup_lock);
38static LIST_HEAD(pwm_lookup_list);
39static DEFINE_MUTEX(pwm_lock);
40static LIST_HEAD(pwm_chips);
41static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
42static RADIX_TREE(pwm_tree, GFP_KERNEL);
43
44static struct pwm_device *pwm_to_device(unsigned int pwm)
45{
46 return radix_tree_lookup(&pwm_tree, pwm);
47}
48
49static int alloc_pwms(int pwm, unsigned int count)
50{
51 unsigned int from = 0;
52 unsigned int start;
53
54 if (pwm >= MAX_PWMS)
55 return -EINVAL;
56
57 if (pwm >= 0)
58 from = pwm;
59
60 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
61 count, 0);
62
63 if (pwm >= 0 && start != pwm)
64 return -EEXIST;
65
66 if (start + count > MAX_PWMS)
67 return -ENOSPC;
68
69 return start;
70}
71
72static void free_pwms(struct pwm_chip *chip)
73{
74 unsigned int i;
75
76 for (i = 0; i < chip->npwm; i++) {
77 struct pwm_device *pwm = &chip->pwms[i];
78
79 radix_tree_delete(&pwm_tree, pwm->pwm);
80 }
81
82 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
83
84 kfree(chip->pwms);
85 chip->pwms = NULL;
86}
87
88static struct pwm_chip *pwmchip_find_by_name(const char *name)
89{
90 struct pwm_chip *chip;
91
92 if (!name)
93 return NULL;
94
95 mutex_lock(&pwm_lock);
96
97 list_for_each_entry(chip, &pwm_chips, list) {
98 const char *chip_name = dev_name(chip->dev);
99
100 if (chip_name && strcmp(chip_name, name) == 0) {
101 mutex_unlock(&pwm_lock);
102 return chip;
103 }
104 }
105
106 mutex_unlock(&pwm_lock);
107
108 return NULL;
109}
110
111static int pwm_device_request(struct pwm_device *pwm, const char *label)
112{
113 int err;
114
115 if (test_bit(PWMF_REQUESTED, &pwm->flags))
116 return -EBUSY;
117
118 if (!try_module_get(pwm->chip->ops->owner))
119 return -ENODEV;
120
121 if (pwm->chip->ops->request) {
122 err = pwm->chip->ops->request(pwm->chip, pwm);
123 if (err) {
124 module_put(pwm->chip->ops->owner);
125 return err;
126 }
127 }
128
129 set_bit(PWMF_REQUESTED, &pwm->flags);
130 pwm->label = label;
131
132 return 0;
133}
134
135struct pwm_device *
136of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
137{
138 struct pwm_device *pwm;
139
140 if (pc->of_pwm_n_cells < 3)
141 return ERR_PTR(-EINVAL);
142
143 if (args->args[0] >= pc->npwm)
144 return ERR_PTR(-EINVAL);
145
146 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
147 if (IS_ERR(pwm))
148 return pwm;
149
150 pwm->args.period = args->args[1];
151
152 if (args->args[2] & PWM_POLARITY_INVERTED)
153 pwm->args.polarity = PWM_POLARITY_INVERSED;
154 else
155 pwm->args.polarity = PWM_POLARITY_NORMAL;
156
157 return pwm;
158}
159EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
160
161static struct pwm_device *
162of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
163{
164 struct pwm_device *pwm;
165
166 if (pc->of_pwm_n_cells < 2)
167 return ERR_PTR(-EINVAL);
168
169 if (args->args[0] >= pc->npwm)
170 return ERR_PTR(-EINVAL);
171
172 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
173 if (IS_ERR(pwm))
174 return pwm;
175
176 pwm->args.period = args->args[1];
177
178 return pwm;
179}
180
181static void of_pwmchip_add(struct pwm_chip *chip)
182{
183 if (!chip->dev || !chip->dev->of_node)
184 return;
185
186 if (!chip->of_xlate) {
187 chip->of_xlate = of_pwm_simple_xlate;
188 chip->of_pwm_n_cells = 2;
189 }
190
191 of_node_get(chip->dev->of_node);
192}
193
194static void of_pwmchip_remove(struct pwm_chip *chip)
195{
196 if (chip->dev)
197 of_node_put(chip->dev->of_node);
198}
199
200/**
201 * pwm_set_chip_data() - set private chip data for a PWM
202 * @pwm: PWM device
203 * @data: pointer to chip-specific data
204 *
205 * Returns: 0 on success or a negative error code on failure.
206 */
207int pwm_set_chip_data(struct pwm_device *pwm, void *data)
208{
209 if (!pwm)
210 return -EINVAL;
211
212 pwm->chip_data = data;
213
214 return 0;
215}
216EXPORT_SYMBOL_GPL(pwm_set_chip_data);
217
218/**
219 * pwm_get_chip_data() - get private chip data for a PWM
220 * @pwm: PWM device
221 *
222 * Returns: A pointer to the chip-private data for the PWM device.
223 */
224void *pwm_get_chip_data(struct pwm_device *pwm)
225{
226 return pwm ? pwm->chip_data : NULL;
227}
228EXPORT_SYMBOL_GPL(pwm_get_chip_data);
229
230static bool pwm_ops_check(const struct pwm_ops *ops)
231{
232 /* driver supports legacy, non-atomic operation */
233 if (ops->config && ops->enable && ops->disable)
234 return true;
235
236 /* driver supports atomic operation */
237 if (ops->apply)
238 return true;
239
240 return false;
241}
242
243/**
244 * pwmchip_add_with_polarity() - register a new PWM chip
245 * @chip: the PWM chip to add
246 * @polarity: initial polarity of PWM channels
247 *
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.
251 *
252 * Returns: 0 on success or a negative error code on failure.
253 */
254int pwmchip_add_with_polarity(struct pwm_chip *chip,
255 enum pwm_polarity polarity)
256{
257 struct pwm_device *pwm;
258 unsigned int i;
259 int ret;
260
261 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
262 return -EINVAL;
263
264 if (!pwm_ops_check(chip->ops))
265 return -EINVAL;
266
267 mutex_lock(&pwm_lock);
268
269 ret = alloc_pwms(chip->base, chip->npwm);
270 if (ret < 0)
271 goto out;
272
273 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
274 if (!chip->pwms) {
275 ret = -ENOMEM;
276 goto out;
277 }
278
279 chip->base = ret;
280
281 for (i = 0; i < chip->npwm; i++) {
282 pwm = &chip->pwms[i];
283
284 pwm->chip = chip;
285 pwm->pwm = chip->base + i;
286 pwm->hwpwm = i;
287 pwm->state.polarity = polarity;
288
289 if (chip->ops->get_state)
290 chip->ops->get_state(chip, pwm, &pwm->state);
291
292 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
293 }
294
295 bitmap_set(allocated_pwms, chip->base, chip->npwm);
296
297 INIT_LIST_HEAD(&chip->list);
298 list_add(&chip->list, &pwm_chips);
299
300 ret = 0;
301
302 if (IS_ENABLED(CONFIG_OF))
303 of_pwmchip_add(chip);
304
305 pwmchip_sysfs_export(chip);
306
307out:
308 mutex_unlock(&pwm_lock);
309 return ret;
310}
311EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
312
313/**
314 * pwmchip_add() - register a new PWM chip
315 * @chip: the PWM chip to add
316 *
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.
319 *
320 * Returns: 0 on success or a negative error code on failure.
321 */
322int pwmchip_add(struct pwm_chip *chip)
323{
324 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
325}
326EXPORT_SYMBOL_GPL(pwmchip_add);
327
328/**
329 * pwmchip_remove() - remove a PWM chip
330 * @chip: the PWM chip to remove
331 *
332 * Removes a PWM chip. This function may return busy if the PWM chip provides
333 * a PWM device that is still requested.
334 *
335 * Returns: 0 on success or a negative error code on failure.
336 */
337int pwmchip_remove(struct pwm_chip *chip)
338{
339 unsigned int i;
340 int ret = 0;
341
342 pwmchip_sysfs_unexport_children(chip);
343
344 mutex_lock(&pwm_lock);
345
346 for (i = 0; i < chip->npwm; i++) {
347 struct pwm_device *pwm = &chip->pwms[i];
348
349 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
350 ret = -EBUSY;
351 goto out;
352 }
353 }
354
355 list_del_init(&chip->list);
356
357 if (IS_ENABLED(CONFIG_OF))
358 of_pwmchip_remove(chip);
359
360 free_pwms(chip);
361
362 pwmchip_sysfs_unexport(chip);
363
364out:
365 mutex_unlock(&pwm_lock);
366 return ret;
367}
368EXPORT_SYMBOL_GPL(pwmchip_remove);
369
370/**
371 * pwm_request() - request a PWM device
372 * @pwm: global PWM device index
373 * @label: PWM device label
374 *
375 * This function is deprecated, use pwm_get() instead.
376 *
377 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
378 * failure.
379 */
380struct pwm_device *pwm_request(int pwm, const char *label)
381{
382 struct pwm_device *dev;
383 int err;
384
385 if (pwm < 0 || pwm >= MAX_PWMS)
386 return ERR_PTR(-EINVAL);
387
388 mutex_lock(&pwm_lock);
389
390 dev = pwm_to_device(pwm);
391 if (!dev) {
392 dev = ERR_PTR(-EPROBE_DEFER);
393 goto out;
394 }
395
396 err = pwm_device_request(dev, label);
397 if (err < 0)
398 dev = ERR_PTR(err);
399
400out:
401 mutex_unlock(&pwm_lock);
402
403 return dev;
404}
405EXPORT_SYMBOL_GPL(pwm_request);
406
407/**
408 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
409 * @chip: PWM chip
410 * @index: per-chip index of the PWM to request
411 * @label: a literal description string of this PWM
412 *
413 * Returns: A pointer to the PWM device at the given index of the given PWM
414 * chip. A negative error code is returned if the index is not valid for the
415 * specified PWM chip or if the PWM device cannot be requested.
416 */
417struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
418 unsigned int index,
419 const char *label)
420{
421 struct pwm_device *pwm;
422 int err;
423
424 if (!chip || index >= chip->npwm)
425 return ERR_PTR(-EINVAL);
426
427 mutex_lock(&pwm_lock);
428 pwm = &chip->pwms[index];
429
430 err = pwm_device_request(pwm, label);
431 if (err < 0)
432 pwm = ERR_PTR(err);
433
434 mutex_unlock(&pwm_lock);
435 return pwm;
436}
437EXPORT_SYMBOL_GPL(pwm_request_from_chip);
438
439/**
440 * pwm_free() - free a PWM device
441 * @pwm: PWM device
442 *
443 * This function is deprecated, use pwm_put() instead.
444 */
445void pwm_free(struct pwm_device *pwm)
446{
447 pwm_put(pwm);
448}
449EXPORT_SYMBOL_GPL(pwm_free);
450
451/**
452 * pwm_apply_state() - atomically apply a new state to a PWM device
453 * @pwm: PWM device
454 * @state: new state to apply. This can be adjusted by the PWM driver
455 * if the requested config is not achievable, for example,
456 * ->duty_cycle and ->period might be approximated.
457 */
458int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
459{
460 int err;
461
462 if (!pwm || !state || !state->period ||
463 state->duty_cycle > state->period)
464 return -EINVAL;
465
466 if (!memcmp(state, &pwm->state, sizeof(*state)))
467 return 0;
468
469 if (pwm->chip->ops->apply) {
470 err = pwm->chip->ops->apply(pwm->chip, pwm, state);
471 if (err)
472 return err;
473
474 pwm->state = *state;
475 } else {
476 /*
477 * FIXME: restore the initial state in case of error.
478 */
479 if (state->polarity != pwm->state.polarity) {
480 if (!pwm->chip->ops->set_polarity)
481 return -ENOTSUPP;
482
483 /*
484 * Changing the polarity of a running PWM is
485 * only allowed when the PWM driver implements
486 * ->apply().
487 */
488 if (pwm->state.enabled) {
489 pwm->chip->ops->disable(pwm->chip, pwm);
490 pwm->state.enabled = false;
491 }
492
493 err = pwm->chip->ops->set_polarity(pwm->chip, pwm,
494 state->polarity);
495 if (err)
496 return err;
497
498 pwm->state.polarity = state->polarity;
499 }
500
501 if (state->period != pwm->state.period ||
502 state->duty_cycle != pwm->state.duty_cycle) {
503 err = pwm->chip->ops->config(pwm->chip, pwm,
504 state->duty_cycle,
505 state->period);
506 if (err)
507 return err;
508
509 pwm->state.duty_cycle = state->duty_cycle;
510 pwm->state.period = state->period;
511 }
512
513 if (state->enabled != pwm->state.enabled) {
514 if (state->enabled) {
515 err = pwm->chip->ops->enable(pwm->chip, pwm);
516 if (err)
517 return err;
518 } else {
519 pwm->chip->ops->disable(pwm->chip, pwm);
520 }
521
522 pwm->state.enabled = state->enabled;
523 }
524 }
525
526 return 0;
527}
528EXPORT_SYMBOL_GPL(pwm_apply_state);
529
530/**
531 * pwm_capture() - capture and report a PWM signal
532 * @pwm: PWM device
533 * @result: structure to fill with capture result
534 * @timeout: time to wait, in milliseconds, before giving up on capture
535 *
536 * Returns: 0 on success or a negative error code on failure.
537 */
538int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
539 unsigned long timeout)
540{
541 int err;
542
543 if (!pwm || !pwm->chip->ops)
544 return -EINVAL;
545
546 if (!pwm->chip->ops->capture)
547 return -ENOSYS;
548
549 mutex_lock(&pwm_lock);
550 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
551 mutex_unlock(&pwm_lock);
552
553 return err;
554}
555EXPORT_SYMBOL_GPL(pwm_capture);
556
557/**
558 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
559 * @pwm: PWM device
560 *
561 * This function will adjust the PWM config to the PWM arguments provided
562 * by the DT or PWM lookup table. This is particularly useful to adapt
563 * the bootloader config to the Linux one.
564 */
565int pwm_adjust_config(struct pwm_device *pwm)
566{
567 struct pwm_state state;
568 struct pwm_args pargs;
569
570 pwm_get_args(pwm, &pargs);
571 pwm_get_state(pwm, &state);
572
573 /*
574 * If the current period is zero it means that either the PWM driver
575 * does not support initial state retrieval or the PWM has not yet
576 * been configured.
577 *
578 * In either case, we setup the new period and polarity, and assign a
579 * duty cycle of 0.
580 */
581 if (!state.period) {
582 state.duty_cycle = 0;
583 state.period = pargs.period;
584 state.polarity = pargs.polarity;
585
586 return pwm_apply_state(pwm, &state);
587 }
588
589 /*
590 * Adjust the PWM duty cycle/period based on the period value provided
591 * in PWM args.
592 */
593 if (pargs.period != state.period) {
594 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
595
596 do_div(dutycycle, state.period);
597 state.duty_cycle = dutycycle;
598 state.period = pargs.period;
599 }
600
601 /*
602 * If the polarity changed, we should also change the duty cycle.
603 */
604 if (pargs.polarity != state.polarity) {
605 state.polarity = pargs.polarity;
606 state.duty_cycle = state.period - state.duty_cycle;
607 }
608
609 return pwm_apply_state(pwm, &state);
610}
611EXPORT_SYMBOL_GPL(pwm_adjust_config);
612
613static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
614{
615 struct pwm_chip *chip;
616
617 mutex_lock(&pwm_lock);
618
619 list_for_each_entry(chip, &pwm_chips, list)
620 if (chip->dev && chip->dev->of_node == np) {
621 mutex_unlock(&pwm_lock);
622 return chip;
623 }
624
625 mutex_unlock(&pwm_lock);
626
627 return ERR_PTR(-EPROBE_DEFER);
628}
629
630/**
631 * of_pwm_get() - request a PWM via the PWM framework
632 * @np: device node to get the PWM from
633 * @con_id: consumer name
634 *
635 * Returns the PWM device parsed from the phandle and index specified in the
636 * "pwms" property of a device tree node or a negative error-code on failure.
637 * Values parsed from the device tree are stored in the returned PWM device
638 * object.
639 *
640 * If con_id is NULL, the first PWM device listed in the "pwms" property will
641 * be requested. Otherwise the "pwm-names" property is used to do a reverse
642 * lookup of the PWM index. This also means that the "pwm-names" property
643 * becomes mandatory for devices that look up the PWM device via the con_id
644 * parameter.
645 *
646 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
647 * error code on failure.
648 */
649struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
650{
651 struct pwm_device *pwm = NULL;
652 struct of_phandle_args args;
653 struct pwm_chip *pc;
654 int index = 0;
655 int err;
656
657 if (con_id) {
658 index = of_property_match_string(np, "pwm-names", con_id);
659 if (index < 0)
660 return ERR_PTR(index);
661 }
662
663 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
664 &args);
665 if (err) {
666 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
667 return ERR_PTR(err);
668 }
669
670 pc = of_node_to_pwmchip(args.np);
671 if (IS_ERR(pc)) {
672 pr_debug("%s(): PWM chip not found\n", __func__);
673 pwm = ERR_CAST(pc);
674 goto put;
675 }
676
677 if (args.args_count != pc->of_pwm_n_cells) {
678 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
679 args.np->full_name);
680 pwm = ERR_PTR(-EINVAL);
681 goto put;
682 }
683
684 pwm = pc->of_xlate(pc, &args);
685 if (IS_ERR(pwm))
686 goto put;
687
688 /*
689 * If a consumer name was not given, try to look it up from the
690 * "pwm-names" property if it exists. Otherwise use the name of
691 * the user device node.
692 */
693 if (!con_id) {
694 err = of_property_read_string_index(np, "pwm-names", index,
695 &con_id);
696 if (err < 0)
697 con_id = np->name;
698 }
699
700 pwm->label = con_id;
701
702put:
703 of_node_put(args.np);
704
705 return pwm;
706}
707EXPORT_SYMBOL_GPL(of_pwm_get);
708
709/**
710 * pwm_add_table() - register PWM device consumers
711 * @table: array of consumers to register
712 * @num: number of consumers in table
713 */
714void pwm_add_table(struct pwm_lookup *table, size_t num)
715{
716 mutex_lock(&pwm_lookup_lock);
717
718 while (num--) {
719 list_add_tail(&table->list, &pwm_lookup_list);
720 table++;
721 }
722
723 mutex_unlock(&pwm_lookup_lock);
724}
725
726/**
727 * pwm_remove_table() - unregister PWM device consumers
728 * @table: array of consumers to unregister
729 * @num: number of consumers in table
730 */
731void pwm_remove_table(struct pwm_lookup *table, size_t num)
732{
733 mutex_lock(&pwm_lookup_lock);
734
735 while (num--) {
736 list_del(&table->list);
737 table++;
738 }
739
740 mutex_unlock(&pwm_lookup_lock);
741}
742
743/**
744 * pwm_get() - look up and request a PWM device
745 * @dev: device for PWM consumer
746 * @con_id: consumer name
747 *
748 * Lookup is first attempted using DT. If the device was not instantiated from
749 * a device tree, a PWM chip and a relative index is looked up via a table
750 * supplied by board setup code (see pwm_add_table()).
751 *
752 * Once a PWM chip has been found the specified PWM device will be requested
753 * and is ready to be used.
754 *
755 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
756 * error code on failure.
757 */
758struct pwm_device *pwm_get(struct device *dev, const char *con_id)
759{
760 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
761 const char *dev_id = dev ? dev_name(dev) : NULL;
762 struct pwm_chip *chip = NULL;
763 unsigned int best = 0;
764 struct pwm_lookup *p, *chosen = NULL;
765 unsigned int match;
766
767 /* look up via DT first */
768 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
769 return of_pwm_get(dev->of_node, con_id);
770
771 /*
772 * We look up the provider in the static table typically provided by
773 * board setup code. We first try to lookup the consumer device by
774 * name. If the consumer device was passed in as NULL or if no match
775 * was found, we try to find the consumer by directly looking it up
776 * by name.
777 *
778 * If a match is found, the provider PWM chip is looked up by name
779 * and a PWM device is requested using the PWM device per-chip index.
780 *
781 * The lookup algorithm was shamelessly taken from the clock
782 * framework:
783 *
784 * We do slightly fuzzy matching here:
785 * An entry with a NULL ID is assumed to be a wildcard.
786 * If an entry has a device ID, it must match
787 * If an entry has a connection ID, it must match
788 * Then we take the most specific entry - with the following order
789 * of precedence: dev+con > dev only > con only.
790 */
791 mutex_lock(&pwm_lookup_lock);
792
793 list_for_each_entry(p, &pwm_lookup_list, list) {
794 match = 0;
795
796 if (p->dev_id) {
797 if (!dev_id || strcmp(p->dev_id, dev_id))
798 continue;
799
800 match += 2;
801 }
802
803 if (p->con_id) {
804 if (!con_id || strcmp(p->con_id, con_id))
805 continue;
806
807 match += 1;
808 }
809
810 if (match > best) {
811 chosen = p;
812
813 if (match != 3)
814 best = match;
815 else
816 break;
817 }
818 }
819
820 if (!chosen) {
821 pwm = ERR_PTR(-ENODEV);
822 goto out;
823 }
824
825 chip = pwmchip_find_by_name(chosen->provider);
826 if (!chip)
827 goto out;
828
829 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
830 if (IS_ERR(pwm))
831 goto out;
832
833 pwm->args.period = chosen->period;
834 pwm->args.polarity = chosen->polarity;
835
836out:
837 mutex_unlock(&pwm_lookup_lock);
838 return pwm;
839}
840EXPORT_SYMBOL_GPL(pwm_get);
841
842/**
843 * pwm_put() - release a PWM device
844 * @pwm: PWM device
845 */
846void pwm_put(struct pwm_device *pwm)
847{
848 if (!pwm)
849 return;
850
851 mutex_lock(&pwm_lock);
852
853 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
854 pr_warn("PWM device already freed\n");
855 goto out;
856 }
857
858 if (pwm->chip->ops->free)
859 pwm->chip->ops->free(pwm->chip, pwm);
860
861 pwm->label = NULL;
862
863 module_put(pwm->chip->ops->owner);
864out:
865 mutex_unlock(&pwm_lock);
866}
867EXPORT_SYMBOL_GPL(pwm_put);
868
869static void devm_pwm_release(struct device *dev, void *res)
870{
871 pwm_put(*(struct pwm_device **)res);
872}
873
874/**
875 * devm_pwm_get() - resource managed pwm_get()
876 * @dev: device for PWM consumer
877 * @con_id: consumer name
878 *
879 * This function performs like pwm_get() but the acquired PWM device will
880 * automatically be released on driver detach.
881 *
882 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
883 * error code on failure.
884 */
885struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
886{
887 struct pwm_device **ptr, *pwm;
888
889 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
890 if (!ptr)
891 return ERR_PTR(-ENOMEM);
892
893 pwm = pwm_get(dev, con_id);
894 if (!IS_ERR(pwm)) {
895 *ptr = pwm;
896 devres_add(dev, ptr);
897 } else {
898 devres_free(ptr);
899 }
900
901 return pwm;
902}
903EXPORT_SYMBOL_GPL(devm_pwm_get);
904
905/**
906 * devm_of_pwm_get() - resource managed of_pwm_get()
907 * @dev: device for PWM consumer
908 * @np: device node to get the PWM from
909 * @con_id: consumer name
910 *
911 * This function performs like of_pwm_get() but the acquired PWM device will
912 * automatically be released on driver detach.
913 *
914 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
915 * error code on failure.
916 */
917struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
918 const char *con_id)
919{
920 struct pwm_device **ptr, *pwm;
921
922 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
923 if (!ptr)
924 return ERR_PTR(-ENOMEM);
925
926 pwm = of_pwm_get(np, con_id);
927 if (!IS_ERR(pwm)) {
928 *ptr = pwm;
929 devres_add(dev, ptr);
930 } else {
931 devres_free(ptr);
932 }
933
934 return pwm;
935}
936EXPORT_SYMBOL_GPL(devm_of_pwm_get);
937
938static int devm_pwm_match(struct device *dev, void *res, void *data)
939{
940 struct pwm_device **p = res;
941
942 if (WARN_ON(!p || !*p))
943 return 0;
944
945 return *p == data;
946}
947
948/**
949 * devm_pwm_put() - resource managed pwm_put()
950 * @dev: device for PWM consumer
951 * @pwm: PWM device
952 *
953 * Release a PWM previously allocated using devm_pwm_get(). Calling this
954 * function is usually not needed because devm-allocated resources are
955 * automatically released on driver detach.
956 */
957void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
958{
959 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
960}
961EXPORT_SYMBOL_GPL(devm_pwm_put);
962
963/**
964 * pwm_can_sleep() - report whether PWM access will sleep
965 * @pwm: PWM device
966 *
967 * Returns: True if accessing the PWM can sleep, false otherwise.
968 */
969bool pwm_can_sleep(struct pwm_device *pwm)
970{
971 return true;
972}
973EXPORT_SYMBOL_GPL(pwm_can_sleep);
974
975#ifdef CONFIG_DEBUG_FS
976static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
977{
978 unsigned int i;
979
980 for (i = 0; i < chip->npwm; i++) {
981 struct pwm_device *pwm = &chip->pwms[i];
982 struct pwm_state state;
983
984 pwm_get_state(pwm, &state);
985
986 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
987
988 if (test_bit(PWMF_REQUESTED, &pwm->flags))
989 seq_puts(s, " requested");
990
991 if (state.enabled)
992 seq_puts(s, " enabled");
993
994 seq_printf(s, " period: %u ns", state.period);
995 seq_printf(s, " duty: %u ns", state.duty_cycle);
996 seq_printf(s, " polarity: %s",
997 state.polarity ? "inverse" : "normal");
998
999 seq_puts(s, "\n");
1000 }
1001}
1002
1003static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1004{
1005 mutex_lock(&pwm_lock);
1006 s->private = "";
1007
1008 return seq_list_start(&pwm_chips, *pos);
1009}
1010
1011static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1012{
1013 s->private = "\n";
1014
1015 return seq_list_next(v, &pwm_chips, pos);
1016}
1017
1018static void pwm_seq_stop(struct seq_file *s, void *v)
1019{
1020 mutex_unlock(&pwm_lock);
1021}
1022
1023static int pwm_seq_show(struct seq_file *s, void *v)
1024{
1025 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1026
1027 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1028 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1029 dev_name(chip->dev), chip->npwm,
1030 (chip->npwm != 1) ? "s" : "");
1031
1032 if (chip->ops->dbg_show)
1033 chip->ops->dbg_show(chip, s);
1034 else
1035 pwm_dbg_show(chip, s);
1036
1037 return 0;
1038}
1039
1040static const struct seq_operations pwm_seq_ops = {
1041 .start = pwm_seq_start,
1042 .next = pwm_seq_next,
1043 .stop = pwm_seq_stop,
1044 .show = pwm_seq_show,
1045};
1046
1047static int pwm_seq_open(struct inode *inode, struct file *file)
1048{
1049 return seq_open(file, &pwm_seq_ops);
1050}
1051
1052static const struct file_operations pwm_debugfs_ops = {
1053 .owner = THIS_MODULE,
1054 .open = pwm_seq_open,
1055 .read = seq_read,
1056 .llseek = seq_lseek,
1057 .release = seq_release,
1058};
1059
1060static int __init pwm_debugfs_init(void)
1061{
1062 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1063 &pwm_debugfs_ops);
1064
1065 return 0;
1066}
1067subsys_initcall(pwm_debugfs_init);
1068#endif /* CONFIG_DEBUG_FS */