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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);
30
31/* protects access to pwm_chips, allocated_pwms, and pwm_tree */
32static DEFINE_MUTEX(pwm_lock);
33
34static LIST_HEAD(pwm_chips);
35static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
36static RADIX_TREE(pwm_tree, GFP_KERNEL);
37
38static struct pwm_device *pwm_to_device(unsigned int pwm)
39{
40 return radix_tree_lookup(&pwm_tree, pwm);
41}
42
43/* Called with pwm_lock held */
44static int alloc_pwms(unsigned int count)
45{
46 unsigned int start;
47
48 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, 0,
49 count, 0);
50
51 if (start + count > MAX_PWMS)
52 return -ENOSPC;
53
54 bitmap_set(allocated_pwms, start, count);
55
56 return start;
57}
58
59/* Called with pwm_lock held */
60static void free_pwms(struct pwm_chip *chip)
61{
62 unsigned int i;
63
64 for (i = 0; i < chip->npwm; i++) {
65 struct pwm_device *pwm = &chip->pwms[i];
66
67 radix_tree_delete(&pwm_tree, pwm->pwm);
68 }
69
70 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
71
72 kfree(chip->pwms);
73 chip->pwms = NULL;
74}
75
76static struct pwm_chip *pwmchip_find_by_name(const char *name)
77{
78 struct pwm_chip *chip;
79
80 if (!name)
81 return NULL;
82
83 mutex_lock(&pwm_lock);
84
85 list_for_each_entry(chip, &pwm_chips, list) {
86 const char *chip_name = dev_name(chip->dev);
87
88 if (chip_name && strcmp(chip_name, name) == 0) {
89 mutex_unlock(&pwm_lock);
90 return chip;
91 }
92 }
93
94 mutex_unlock(&pwm_lock);
95
96 return NULL;
97}
98
99static int pwm_device_request(struct pwm_device *pwm, const char *label)
100{
101 int err;
102
103 if (test_bit(PWMF_REQUESTED, &pwm->flags))
104 return -EBUSY;
105
106 if (!try_module_get(pwm->chip->ops->owner))
107 return -ENODEV;
108
109 if (pwm->chip->ops->request) {
110 err = pwm->chip->ops->request(pwm->chip, pwm);
111 if (err) {
112 module_put(pwm->chip->ops->owner);
113 return err;
114 }
115 }
116
117 if (pwm->chip->ops->get_state) {
118 struct pwm_state state;
119
120 err = pwm->chip->ops->get_state(pwm->chip, pwm, &state);
121 trace_pwm_get(pwm, &state, err);
122
123 if (!err)
124 pwm->state = state;
125
126 if (IS_ENABLED(CONFIG_PWM_DEBUG))
127 pwm->last = pwm->state;
128 }
129
130 set_bit(PWMF_REQUESTED, &pwm->flags);
131 pwm->label = label;
132
133 return 0;
134}
135
136struct pwm_device *
137of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
138{
139 struct pwm_device *pwm;
140
141 if (pc->of_pwm_n_cells < 2)
142 return ERR_PTR(-EINVAL);
143
144 /* flags in the third cell are optional */
145 if (args->args_count < 2)
146 return ERR_PTR(-EINVAL);
147
148 if (args->args[0] >= pc->npwm)
149 return ERR_PTR(-EINVAL);
150
151 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
152 if (IS_ERR(pwm))
153 return pwm;
154
155 pwm->args.period = args->args[1];
156 pwm->args.polarity = PWM_POLARITY_NORMAL;
157
158 if (pc->of_pwm_n_cells >= 3) {
159 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
160 pwm->args.polarity = PWM_POLARITY_INVERSED;
161 }
162
163 return pwm;
164}
165EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
166
167struct pwm_device *
168of_pwm_single_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
169{
170 struct pwm_device *pwm;
171
172 if (pc->of_pwm_n_cells < 1)
173 return ERR_PTR(-EINVAL);
174
175 /* validate that one cell is specified, optionally with flags */
176 if (args->args_count != 1 && args->args_count != 2)
177 return ERR_PTR(-EINVAL);
178
179 pwm = pwm_request_from_chip(pc, 0, NULL);
180 if (IS_ERR(pwm))
181 return pwm;
182
183 pwm->args.period = args->args[0];
184 pwm->args.polarity = PWM_POLARITY_NORMAL;
185
186 if (args->args_count == 2 && args->args[2] & PWM_POLARITY_INVERTED)
187 pwm->args.polarity = PWM_POLARITY_INVERSED;
188
189 return pwm;
190}
191EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
192
193static void of_pwmchip_add(struct pwm_chip *chip)
194{
195 if (!chip->dev || !chip->dev->of_node)
196 return;
197
198 if (!chip->of_xlate) {
199 u32 pwm_cells;
200
201 if (of_property_read_u32(chip->dev->of_node, "#pwm-cells",
202 &pwm_cells))
203 pwm_cells = 2;
204
205 chip->of_xlate = of_pwm_xlate_with_flags;
206 chip->of_pwm_n_cells = pwm_cells;
207 }
208
209 of_node_get(chip->dev->of_node);
210}
211
212static void of_pwmchip_remove(struct pwm_chip *chip)
213{
214 if (chip->dev)
215 of_node_put(chip->dev->of_node);
216}
217
218/**
219 * pwm_set_chip_data() - set private chip data for a PWM
220 * @pwm: PWM device
221 * @data: pointer to chip-specific data
222 *
223 * Returns: 0 on success or a negative error code on failure.
224 */
225int pwm_set_chip_data(struct pwm_device *pwm, void *data)
226{
227 if (!pwm)
228 return -EINVAL;
229
230 pwm->chip_data = data;
231
232 return 0;
233}
234EXPORT_SYMBOL_GPL(pwm_set_chip_data);
235
236/**
237 * pwm_get_chip_data() - get private chip data for a PWM
238 * @pwm: PWM device
239 *
240 * Returns: A pointer to the chip-private data for the PWM device.
241 */
242void *pwm_get_chip_data(struct pwm_device *pwm)
243{
244 return pwm ? pwm->chip_data : NULL;
245}
246EXPORT_SYMBOL_GPL(pwm_get_chip_data);
247
248static bool pwm_ops_check(const struct pwm_chip *chip)
249{
250 const struct pwm_ops *ops = chip->ops;
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() - register a new PWM chip
264 * @chip: the PWM chip to add
265 *
266 * Register a new PWM chip.
267 *
268 * Returns: 0 on success or a negative error code on failure.
269 */
270int pwmchip_add(struct pwm_chip *chip)
271{
272 struct pwm_device *pwm;
273 unsigned int i;
274 int ret;
275
276 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
277 return -EINVAL;
278
279 if (!pwm_ops_check(chip))
280 return -EINVAL;
281
282 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
283 if (!chip->pwms)
284 return -ENOMEM;
285
286 mutex_lock(&pwm_lock);
287
288 ret = alloc_pwms(chip->npwm);
289 if (ret < 0) {
290 mutex_unlock(&pwm_lock);
291 kfree(chip->pwms);
292 return ret;
293 }
294
295 chip->base = ret;
296
297 for (i = 0; i < chip->npwm; i++) {
298 pwm = &chip->pwms[i];
299
300 pwm->chip = chip;
301 pwm->pwm = chip->base + i;
302 pwm->hwpwm = i;
303
304 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
305 }
306
307 list_add(&chip->list, &pwm_chips);
308
309 mutex_unlock(&pwm_lock);
310
311 if (IS_ENABLED(CONFIG_OF))
312 of_pwmchip_add(chip);
313
314 pwmchip_sysfs_export(chip);
315
316 return 0;
317}
318EXPORT_SYMBOL_GPL(pwmchip_add);
319
320/**
321 * pwmchip_remove() - remove a PWM chip
322 * @chip: the PWM chip to remove
323 *
324 * Removes a PWM chip. This function may return busy if the PWM chip provides
325 * a PWM device that is still requested.
326 *
327 * Returns: 0 on success or a negative error code on failure.
328 */
329void pwmchip_remove(struct pwm_chip *chip)
330{
331 pwmchip_sysfs_unexport(chip);
332
333 mutex_lock(&pwm_lock);
334
335 list_del_init(&chip->list);
336
337 if (IS_ENABLED(CONFIG_OF))
338 of_pwmchip_remove(chip);
339
340 free_pwms(chip);
341
342 mutex_unlock(&pwm_lock);
343}
344EXPORT_SYMBOL_GPL(pwmchip_remove);
345
346static void devm_pwmchip_remove(void *data)
347{
348 struct pwm_chip *chip = data;
349
350 pwmchip_remove(chip);
351}
352
353int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip)
354{
355 int ret;
356
357 ret = pwmchip_add(chip);
358 if (ret)
359 return ret;
360
361 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
362}
363EXPORT_SYMBOL_GPL(devm_pwmchip_add);
364
365/**
366 * pwm_request() - request a PWM device
367 * @pwm: global PWM device index
368 * @label: PWM device label
369 *
370 * This function is deprecated, use pwm_get() instead.
371 *
372 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
373 * failure.
374 */
375struct pwm_device *pwm_request(int pwm, const char *label)
376{
377 struct pwm_device *dev;
378 int err;
379
380 if (pwm < 0 || pwm >= MAX_PWMS)
381 return ERR_PTR(-EINVAL);
382
383 mutex_lock(&pwm_lock);
384
385 dev = pwm_to_device(pwm);
386 if (!dev) {
387 dev = ERR_PTR(-EPROBE_DEFER);
388 goto out;
389 }
390
391 err = pwm_device_request(dev, label);
392 if (err < 0)
393 dev = ERR_PTR(err);
394
395out:
396 mutex_unlock(&pwm_lock);
397
398 return dev;
399}
400EXPORT_SYMBOL_GPL(pwm_request);
401
402/**
403 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
404 * @chip: PWM chip
405 * @index: per-chip index of the PWM to request
406 * @label: a literal description string of this PWM
407 *
408 * Returns: A pointer to the PWM device at the given index of the given PWM
409 * chip. A negative error code is returned if the index is not valid for the
410 * specified PWM chip or if the PWM device cannot be requested.
411 */
412struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
413 unsigned int index,
414 const char *label)
415{
416 struct pwm_device *pwm;
417 int err;
418
419 if (!chip || index >= chip->npwm)
420 return ERR_PTR(-EINVAL);
421
422 mutex_lock(&pwm_lock);
423 pwm = &chip->pwms[index];
424
425 err = pwm_device_request(pwm, label);
426 if (err < 0)
427 pwm = ERR_PTR(err);
428
429 mutex_unlock(&pwm_lock);
430 return pwm;
431}
432EXPORT_SYMBOL_GPL(pwm_request_from_chip);
433
434/**
435 * pwm_free() - free a PWM device
436 * @pwm: PWM device
437 *
438 * This function is deprecated, use pwm_put() instead.
439 */
440void pwm_free(struct pwm_device *pwm)
441{
442 pwm_put(pwm);
443}
444EXPORT_SYMBOL_GPL(pwm_free);
445
446static void pwm_apply_state_debug(struct pwm_device *pwm,
447 const struct pwm_state *state)
448{
449 struct pwm_state *last = &pwm->last;
450 struct pwm_chip *chip = pwm->chip;
451 struct pwm_state s1, s2;
452 int err;
453
454 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
455 return;
456
457 /* No reasonable diagnosis possible without .get_state() */
458 if (!chip->ops->get_state)
459 return;
460
461 /*
462 * *state was just applied. Read out the hardware state and do some
463 * checks.
464 */
465
466 err = chip->ops->get_state(chip, pwm, &s1);
467 trace_pwm_get(pwm, &s1, err);
468 if (err)
469 /* If that failed there isn't much to debug */
470 return;
471
472 /*
473 * The lowlevel driver either ignored .polarity (which is a bug) or as
474 * best effort inverted .polarity and fixed .duty_cycle respectively.
475 * Undo this inversion and fixup for further tests.
476 */
477 if (s1.enabled && s1.polarity != state->polarity) {
478 s2.polarity = state->polarity;
479 s2.duty_cycle = s1.period - s1.duty_cycle;
480 s2.period = s1.period;
481 s2.enabled = s1.enabled;
482 } else {
483 s2 = s1;
484 }
485
486 if (s2.polarity != state->polarity &&
487 state->duty_cycle < state->period)
488 dev_warn(chip->dev, ".apply ignored .polarity\n");
489
490 if (state->enabled &&
491 last->polarity == state->polarity &&
492 last->period > s2.period &&
493 last->period <= state->period)
494 dev_warn(chip->dev,
495 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
496 state->period, s2.period, last->period);
497
498 if (state->enabled && state->period < s2.period)
499 dev_warn(chip->dev,
500 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
501 state->period, s2.period);
502
503 if (state->enabled &&
504 last->polarity == state->polarity &&
505 last->period == s2.period &&
506 last->duty_cycle > s2.duty_cycle &&
507 last->duty_cycle <= state->duty_cycle)
508 dev_warn(chip->dev,
509 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
510 state->duty_cycle, state->period,
511 s2.duty_cycle, s2.period,
512 last->duty_cycle, last->period);
513
514 if (state->enabled && state->duty_cycle < s2.duty_cycle)
515 dev_warn(chip->dev,
516 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
517 state->duty_cycle, state->period,
518 s2.duty_cycle, s2.period);
519
520 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
521 dev_warn(chip->dev,
522 "requested disabled, but yielded enabled with duty > 0\n");
523
524 /* reapply the state that the driver reported being configured. */
525 err = chip->ops->apply(chip, pwm, &s1);
526 trace_pwm_apply(pwm, &s1, err);
527 if (err) {
528 *last = s1;
529 dev_err(chip->dev, "failed to reapply current setting\n");
530 return;
531 }
532
533 err = chip->ops->get_state(chip, pwm, last);
534 trace_pwm_get(pwm, last, err);
535 if (err)
536 return;
537
538 /* reapplication of the current state should give an exact match */
539 if (s1.enabled != last->enabled ||
540 s1.polarity != last->polarity ||
541 (s1.enabled && s1.period != last->period) ||
542 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
543 dev_err(chip->dev,
544 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
545 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
546 last->enabled, last->polarity, last->duty_cycle,
547 last->period);
548 }
549}
550
551/**
552 * pwm_apply_state() - atomically apply a new state to a PWM device
553 * @pwm: PWM device
554 * @state: new state to apply
555 */
556int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
557{
558 struct pwm_chip *chip;
559 int err;
560
561 /*
562 * Some lowlevel driver's implementations of .apply() make use of
563 * mutexes, also with some drivers only returning when the new
564 * configuration is active calling pwm_apply_state() from atomic context
565 * is a bad idea. So make it explicit that calling this function might
566 * sleep.
567 */
568 might_sleep();
569
570 if (!pwm || !state || !state->period ||
571 state->duty_cycle > state->period)
572 return -EINVAL;
573
574 chip = pwm->chip;
575
576 if (state->period == pwm->state.period &&
577 state->duty_cycle == pwm->state.duty_cycle &&
578 state->polarity == pwm->state.polarity &&
579 state->enabled == pwm->state.enabled &&
580 state->usage_power == pwm->state.usage_power)
581 return 0;
582
583 err = chip->ops->apply(chip, pwm, state);
584 trace_pwm_apply(pwm, state, err);
585 if (err)
586 return err;
587
588 pwm->state = *state;
589
590 /*
591 * only do this after pwm->state was applied as some
592 * implementations of .get_state depend on this
593 */
594 pwm_apply_state_debug(pwm, state);
595
596 return 0;
597}
598EXPORT_SYMBOL_GPL(pwm_apply_state);
599
600/**
601 * pwm_capture() - capture and report a PWM signal
602 * @pwm: PWM device
603 * @result: structure to fill with capture result
604 * @timeout: time to wait, in milliseconds, before giving up on capture
605 *
606 * Returns: 0 on success or a negative error code on failure.
607 */
608int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
609 unsigned long timeout)
610{
611 int err;
612
613 if (!pwm || !pwm->chip->ops)
614 return -EINVAL;
615
616 if (!pwm->chip->ops->capture)
617 return -ENOSYS;
618
619 mutex_lock(&pwm_lock);
620 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
621 mutex_unlock(&pwm_lock);
622
623 return err;
624}
625EXPORT_SYMBOL_GPL(pwm_capture);
626
627/**
628 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
629 * @pwm: PWM device
630 *
631 * This function will adjust the PWM config to the PWM arguments provided
632 * by the DT or PWM lookup table. This is particularly useful to adapt
633 * the bootloader config to the Linux one.
634 */
635int pwm_adjust_config(struct pwm_device *pwm)
636{
637 struct pwm_state state;
638 struct pwm_args pargs;
639
640 pwm_get_args(pwm, &pargs);
641 pwm_get_state(pwm, &state);
642
643 /*
644 * If the current period is zero it means that either the PWM driver
645 * does not support initial state retrieval or the PWM has not yet
646 * been configured.
647 *
648 * In either case, we setup the new period and polarity, and assign a
649 * duty cycle of 0.
650 */
651 if (!state.period) {
652 state.duty_cycle = 0;
653 state.period = pargs.period;
654 state.polarity = pargs.polarity;
655
656 return pwm_apply_state(pwm, &state);
657 }
658
659 /*
660 * Adjust the PWM duty cycle/period based on the period value provided
661 * in PWM args.
662 */
663 if (pargs.period != state.period) {
664 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
665
666 do_div(dutycycle, state.period);
667 state.duty_cycle = dutycycle;
668 state.period = pargs.period;
669 }
670
671 /*
672 * If the polarity changed, we should also change the duty cycle.
673 */
674 if (pargs.polarity != state.polarity) {
675 state.polarity = pargs.polarity;
676 state.duty_cycle = state.period - state.duty_cycle;
677 }
678
679 return pwm_apply_state(pwm, &state);
680}
681EXPORT_SYMBOL_GPL(pwm_adjust_config);
682
683static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
684{
685 struct pwm_chip *chip;
686
687 mutex_lock(&pwm_lock);
688
689 list_for_each_entry(chip, &pwm_chips, list)
690 if (chip->dev && device_match_fwnode(chip->dev, fwnode)) {
691 mutex_unlock(&pwm_lock);
692 return chip;
693 }
694
695 mutex_unlock(&pwm_lock);
696
697 return ERR_PTR(-EPROBE_DEFER);
698}
699
700static struct device_link *pwm_device_link_add(struct device *dev,
701 struct pwm_device *pwm)
702{
703 struct device_link *dl;
704
705 if (!dev) {
706 /*
707 * No device for the PWM consumer has been provided. It may
708 * impact the PM sequence ordering: the PWM supplier may get
709 * suspended before the consumer.
710 */
711 dev_warn(pwm->chip->dev,
712 "No consumer device specified to create a link to\n");
713 return NULL;
714 }
715
716 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
717 if (!dl) {
718 dev_err(dev, "failed to create device link to %s\n",
719 dev_name(pwm->chip->dev));
720 return ERR_PTR(-EINVAL);
721 }
722
723 return dl;
724}
725
726/**
727 * of_pwm_get() - request a PWM via the PWM framework
728 * @dev: device for PWM consumer
729 * @np: device node to get the PWM from
730 * @con_id: consumer name
731 *
732 * Returns the PWM device parsed from the phandle and index specified in the
733 * "pwms" property of a device tree node or a negative error-code on failure.
734 * Values parsed from the device tree are stored in the returned PWM device
735 * object.
736 *
737 * If con_id is NULL, the first PWM device listed in the "pwms" property will
738 * be requested. Otherwise the "pwm-names" property is used to do a reverse
739 * lookup of the PWM index. This also means that the "pwm-names" property
740 * becomes mandatory for devices that look up the PWM device via the con_id
741 * parameter.
742 *
743 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
744 * error code on failure.
745 */
746static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
747 const char *con_id)
748{
749 struct pwm_device *pwm = NULL;
750 struct of_phandle_args args;
751 struct device_link *dl;
752 struct pwm_chip *pc;
753 int index = 0;
754 int err;
755
756 if (con_id) {
757 index = of_property_match_string(np, "pwm-names", con_id);
758 if (index < 0)
759 return ERR_PTR(index);
760 }
761
762 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
763 &args);
764 if (err) {
765 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
766 return ERR_PTR(err);
767 }
768
769 pc = fwnode_to_pwmchip(of_fwnode_handle(args.np));
770 if (IS_ERR(pc)) {
771 if (PTR_ERR(pc) != -EPROBE_DEFER)
772 pr_err("%s(): PWM chip not found\n", __func__);
773
774 pwm = ERR_CAST(pc);
775 goto put;
776 }
777
778 pwm = pc->of_xlate(pc, &args);
779 if (IS_ERR(pwm))
780 goto put;
781
782 dl = pwm_device_link_add(dev, pwm);
783 if (IS_ERR(dl)) {
784 /* of_xlate ended up calling pwm_request_from_chip() */
785 pwm_free(pwm);
786 pwm = ERR_CAST(dl);
787 goto put;
788 }
789
790 /*
791 * If a consumer name was not given, try to look it up from the
792 * "pwm-names" property if it exists. Otherwise use the name of
793 * the user device node.
794 */
795 if (!con_id) {
796 err = of_property_read_string_index(np, "pwm-names", index,
797 &con_id);
798 if (err < 0)
799 con_id = np->name;
800 }
801
802 pwm->label = con_id;
803
804put:
805 of_node_put(args.np);
806
807 return pwm;
808}
809
810/**
811 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
812 * @fwnode: firmware node to get the "pwms" property from
813 *
814 * Returns the PWM device parsed from the fwnode and index specified in the
815 * "pwms" property or a negative error-code on failure.
816 * Values parsed from the device tree are stored in the returned PWM device
817 * object.
818 *
819 * This is analogous to of_pwm_get() except con_id is not yet supported.
820 * ACPI entries must look like
821 * Package () {"pwms", Package ()
822 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
823 *
824 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
825 * error code on failure.
826 */
827static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
828{
829 struct pwm_device *pwm;
830 struct fwnode_reference_args args;
831 struct pwm_chip *chip;
832 int ret;
833
834 memset(&args, 0, sizeof(args));
835
836 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
837 if (ret < 0)
838 return ERR_PTR(ret);
839
840 if (args.nargs < 2)
841 return ERR_PTR(-EPROTO);
842
843 chip = fwnode_to_pwmchip(args.fwnode);
844 if (IS_ERR(chip))
845 return ERR_CAST(chip);
846
847 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
848 if (IS_ERR(pwm))
849 return pwm;
850
851 pwm->args.period = args.args[1];
852 pwm->args.polarity = PWM_POLARITY_NORMAL;
853
854 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
855 pwm->args.polarity = PWM_POLARITY_INVERSED;
856
857 return pwm;
858}
859
860/**
861 * pwm_add_table() - register PWM device consumers
862 * @table: array of consumers to register
863 * @num: number of consumers in table
864 */
865void pwm_add_table(struct pwm_lookup *table, size_t num)
866{
867 mutex_lock(&pwm_lookup_lock);
868
869 while (num--) {
870 list_add_tail(&table->list, &pwm_lookup_list);
871 table++;
872 }
873
874 mutex_unlock(&pwm_lookup_lock);
875}
876
877/**
878 * pwm_remove_table() - unregister PWM device consumers
879 * @table: array of consumers to unregister
880 * @num: number of consumers in table
881 */
882void pwm_remove_table(struct pwm_lookup *table, size_t num)
883{
884 mutex_lock(&pwm_lookup_lock);
885
886 while (num--) {
887 list_del(&table->list);
888 table++;
889 }
890
891 mutex_unlock(&pwm_lookup_lock);
892}
893
894/**
895 * pwm_get() - look up and request a PWM device
896 * @dev: device for PWM consumer
897 * @con_id: consumer name
898 *
899 * Lookup is first attempted using DT. If the device was not instantiated from
900 * a device tree, a PWM chip and a relative index is looked up via a table
901 * supplied by board setup code (see pwm_add_table()).
902 *
903 * Once a PWM chip has been found the specified PWM device will be requested
904 * and is ready to be used.
905 *
906 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
907 * error code on failure.
908 */
909struct pwm_device *pwm_get(struct device *dev, const char *con_id)
910{
911 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
912 const char *dev_id = dev ? dev_name(dev) : NULL;
913 struct pwm_device *pwm;
914 struct pwm_chip *chip;
915 struct device_link *dl;
916 unsigned int best = 0;
917 struct pwm_lookup *p, *chosen = NULL;
918 unsigned int match;
919 int err;
920
921 /* look up via DT first */
922 if (is_of_node(fwnode))
923 return of_pwm_get(dev, to_of_node(fwnode), con_id);
924
925 /* then lookup via ACPI */
926 if (is_acpi_node(fwnode)) {
927 pwm = acpi_pwm_get(fwnode);
928 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
929 return pwm;
930 }
931
932 /*
933 * We look up the provider in the static table typically provided by
934 * board setup code. We first try to lookup the consumer device by
935 * name. If the consumer device was passed in as NULL or if no match
936 * was found, we try to find the consumer by directly looking it up
937 * by name.
938 *
939 * If a match is found, the provider PWM chip is looked up by name
940 * and a PWM device is requested using the PWM device per-chip index.
941 *
942 * The lookup algorithm was shamelessly taken from the clock
943 * framework:
944 *
945 * We do slightly fuzzy matching here:
946 * An entry with a NULL ID is assumed to be a wildcard.
947 * If an entry has a device ID, it must match
948 * If an entry has a connection ID, it must match
949 * Then we take the most specific entry - with the following order
950 * of precedence: dev+con > dev only > con only.
951 */
952 mutex_lock(&pwm_lookup_lock);
953
954 list_for_each_entry(p, &pwm_lookup_list, list) {
955 match = 0;
956
957 if (p->dev_id) {
958 if (!dev_id || strcmp(p->dev_id, dev_id))
959 continue;
960
961 match += 2;
962 }
963
964 if (p->con_id) {
965 if (!con_id || strcmp(p->con_id, con_id))
966 continue;
967
968 match += 1;
969 }
970
971 if (match > best) {
972 chosen = p;
973
974 if (match != 3)
975 best = match;
976 else
977 break;
978 }
979 }
980
981 mutex_unlock(&pwm_lookup_lock);
982
983 if (!chosen)
984 return ERR_PTR(-ENODEV);
985
986 chip = pwmchip_find_by_name(chosen->provider);
987
988 /*
989 * If the lookup entry specifies a module, load the module and retry
990 * the PWM chip lookup. This can be used to work around driver load
991 * ordering issues if driver's can't be made to properly support the
992 * deferred probe mechanism.
993 */
994 if (!chip && chosen->module) {
995 err = request_module(chosen->module);
996 if (err == 0)
997 chip = pwmchip_find_by_name(chosen->provider);
998 }
999
1000 if (!chip)
1001 return ERR_PTR(-EPROBE_DEFER);
1002
1003 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1004 if (IS_ERR(pwm))
1005 return pwm;
1006
1007 dl = pwm_device_link_add(dev, pwm);
1008 if (IS_ERR(dl)) {
1009 pwm_free(pwm);
1010 return ERR_CAST(dl);
1011 }
1012
1013 pwm->args.period = chosen->period;
1014 pwm->args.polarity = chosen->polarity;
1015
1016 return pwm;
1017}
1018EXPORT_SYMBOL_GPL(pwm_get);
1019
1020/**
1021 * pwm_put() - release a PWM device
1022 * @pwm: PWM device
1023 */
1024void pwm_put(struct pwm_device *pwm)
1025{
1026 if (!pwm)
1027 return;
1028
1029 mutex_lock(&pwm_lock);
1030
1031 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1032 pr_warn("PWM device already freed\n");
1033 goto out;
1034 }
1035
1036 if (pwm->chip->ops->free)
1037 pwm->chip->ops->free(pwm->chip, pwm);
1038
1039 pwm_set_chip_data(pwm, NULL);
1040 pwm->label = NULL;
1041
1042 module_put(pwm->chip->ops->owner);
1043out:
1044 mutex_unlock(&pwm_lock);
1045}
1046EXPORT_SYMBOL_GPL(pwm_put);
1047
1048static void devm_pwm_release(void *pwm)
1049{
1050 pwm_put(pwm);
1051}
1052
1053/**
1054 * devm_pwm_get() - resource managed pwm_get()
1055 * @dev: device for PWM consumer
1056 * @con_id: consumer name
1057 *
1058 * This function performs like pwm_get() but the acquired PWM device will
1059 * automatically be released on driver detach.
1060 *
1061 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1062 * error code on failure.
1063 */
1064struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1065{
1066 struct pwm_device *pwm;
1067 int ret;
1068
1069 pwm = pwm_get(dev, con_id);
1070 if (IS_ERR(pwm))
1071 return pwm;
1072
1073 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1074 if (ret)
1075 return ERR_PTR(ret);
1076
1077 return pwm;
1078}
1079EXPORT_SYMBOL_GPL(devm_pwm_get);
1080
1081/**
1082 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1083 * @dev: device for PWM consumer
1084 * @fwnode: firmware node to get the PWM from
1085 * @con_id: consumer name
1086 *
1087 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1088 * acpi_pwm_get() for a detailed description.
1089 *
1090 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1091 * error code on failure.
1092 */
1093struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1094 struct fwnode_handle *fwnode,
1095 const char *con_id)
1096{
1097 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1098 int ret;
1099
1100 if (is_of_node(fwnode))
1101 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1102 else if (is_acpi_node(fwnode))
1103 pwm = acpi_pwm_get(fwnode);
1104 if (IS_ERR(pwm))
1105 return pwm;
1106
1107 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1108 if (ret)
1109 return ERR_PTR(ret);
1110
1111 return pwm;
1112}
1113EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1114
1115#ifdef CONFIG_DEBUG_FS
1116static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1117{
1118 unsigned int i;
1119
1120 for (i = 0; i < chip->npwm; i++) {
1121 struct pwm_device *pwm = &chip->pwms[i];
1122 struct pwm_state state;
1123
1124 pwm_get_state(pwm, &state);
1125
1126 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1127
1128 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1129 seq_puts(s, " requested");
1130
1131 if (state.enabled)
1132 seq_puts(s, " enabled");
1133
1134 seq_printf(s, " period: %llu ns", state.period);
1135 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1136 seq_printf(s, " polarity: %s",
1137 state.polarity ? "inverse" : "normal");
1138
1139 if (state.usage_power)
1140 seq_puts(s, " usage_power");
1141
1142 seq_puts(s, "\n");
1143 }
1144}
1145
1146static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1147{
1148 mutex_lock(&pwm_lock);
1149 s->private = "";
1150
1151 return seq_list_start(&pwm_chips, *pos);
1152}
1153
1154static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1155{
1156 s->private = "\n";
1157
1158 return seq_list_next(v, &pwm_chips, pos);
1159}
1160
1161static void pwm_seq_stop(struct seq_file *s, void *v)
1162{
1163 mutex_unlock(&pwm_lock);
1164}
1165
1166static int pwm_seq_show(struct seq_file *s, void *v)
1167{
1168 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1169
1170 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1171 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1172 dev_name(chip->dev), chip->npwm,
1173 (chip->npwm != 1) ? "s" : "");
1174
1175 pwm_dbg_show(chip, s);
1176
1177 return 0;
1178}
1179
1180static const struct seq_operations pwm_debugfs_sops = {
1181 .start = pwm_seq_start,
1182 .next = pwm_seq_next,
1183 .stop = pwm_seq_stop,
1184 .show = pwm_seq_show,
1185};
1186
1187DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1188
1189static int __init pwm_debugfs_init(void)
1190{
1191 debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1192
1193 return 0;
1194}
1195subsys_initcall(pwm_debugfs_init);
1196#endif /* CONFIG_DEBUG_FS */
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 MAX_PWMS 1024
24
25static DEFINE_MUTEX(pwm_lookup_lock);
26static LIST_HEAD(pwm_lookup_list);
27static DEFINE_MUTEX(pwm_lock);
28static LIST_HEAD(pwm_chips);
29static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
30static RADIX_TREE(pwm_tree, GFP_KERNEL);
31
32static struct pwm_device *pwm_to_device(unsigned int pwm)
33{
34 return radix_tree_lookup(&pwm_tree, pwm);
35}
36
37static int alloc_pwms(int pwm, unsigned int count)
38{
39 unsigned int from = 0;
40 unsigned int start;
41
42 if (pwm >= MAX_PWMS)
43 return -EINVAL;
44
45 if (pwm >= 0)
46 from = pwm;
47
48 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
49 count, 0);
50
51 if (pwm >= 0 && start != pwm)
52 return -EEXIST;
53
54 if (start + count > MAX_PWMS)
55 return -ENOSPC;
56
57 return start;
58}
59
60static void free_pwms(struct pwm_chip *chip)
61{
62 unsigned int i;
63
64 for (i = 0; i < chip->npwm; i++) {
65 struct pwm_device *pwm = &chip->pwms[i];
66
67 radix_tree_delete(&pwm_tree, pwm->pwm);
68 }
69
70 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
71
72 kfree(chip->pwms);
73 chip->pwms = NULL;
74}
75
76static struct pwm_chip *pwmchip_find_by_name(const char *name)
77{
78 struct pwm_chip *chip;
79
80 if (!name)
81 return NULL;
82
83 mutex_lock(&pwm_lock);
84
85 list_for_each_entry(chip, &pwm_chips, list) {
86 const char *chip_name = dev_name(chip->dev);
87
88 if (chip_name && strcmp(chip_name, name) == 0) {
89 mutex_unlock(&pwm_lock);
90 return chip;
91 }
92 }
93
94 mutex_unlock(&pwm_lock);
95
96 return NULL;
97}
98
99static int pwm_device_request(struct pwm_device *pwm, const char *label)
100{
101 int err;
102
103 if (test_bit(PWMF_REQUESTED, &pwm->flags))
104 return -EBUSY;
105
106 if (!try_module_get(pwm->chip->ops->owner))
107 return -ENODEV;
108
109 if (pwm->chip->ops->request) {
110 err = pwm->chip->ops->request(pwm->chip, pwm);
111 if (err) {
112 module_put(pwm->chip->ops->owner);
113 return err;
114 }
115 }
116
117 set_bit(PWMF_REQUESTED, &pwm->flags);
118 pwm->label = label;
119
120 return 0;
121}
122
123struct pwm_device *
124of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
125{
126 struct pwm_device *pwm;
127
128 /* check, whether the driver supports a third cell for flags */
129 if (pc->of_pwm_n_cells < 3)
130 return ERR_PTR(-EINVAL);
131
132 /* flags in the third cell are optional */
133 if (args->args_count < 2)
134 return ERR_PTR(-EINVAL);
135
136 if (args->args[0] >= pc->npwm)
137 return ERR_PTR(-EINVAL);
138
139 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
140 if (IS_ERR(pwm))
141 return pwm;
142
143 pwm->args.period = args->args[1];
144 pwm->args.polarity = PWM_POLARITY_NORMAL;
145
146 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
147 pwm->args.polarity = PWM_POLARITY_INVERSED;
148
149 return pwm;
150}
151EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
152
153static struct pwm_device *
154of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
155{
156 struct pwm_device *pwm;
157
158 /* sanity check driver support */
159 if (pc->of_pwm_n_cells < 2)
160 return ERR_PTR(-EINVAL);
161
162 /* all cells are required */
163 if (args->args_count != pc->of_pwm_n_cells)
164 return ERR_PTR(-EINVAL);
165
166 if (args->args[0] >= pc->npwm)
167 return ERR_PTR(-EINVAL);
168
169 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
170 if (IS_ERR(pwm))
171 return pwm;
172
173 pwm->args.period = args->args[1];
174
175 return pwm;
176}
177
178static void of_pwmchip_add(struct pwm_chip *chip)
179{
180 if (!chip->dev || !chip->dev->of_node)
181 return;
182
183 if (!chip->of_xlate) {
184 chip->of_xlate = of_pwm_simple_xlate;
185 chip->of_pwm_n_cells = 2;
186 }
187
188 of_node_get(chip->dev->of_node);
189}
190
191static void of_pwmchip_remove(struct pwm_chip *chip)
192{
193 if (chip->dev)
194 of_node_put(chip->dev->of_node);
195}
196
197/**
198 * pwm_set_chip_data() - set private chip data for a PWM
199 * @pwm: PWM device
200 * @data: pointer to chip-specific data
201 *
202 * Returns: 0 on success or a negative error code on failure.
203 */
204int pwm_set_chip_data(struct pwm_device *pwm, void *data)
205{
206 if (!pwm)
207 return -EINVAL;
208
209 pwm->chip_data = data;
210
211 return 0;
212}
213EXPORT_SYMBOL_GPL(pwm_set_chip_data);
214
215/**
216 * pwm_get_chip_data() - get private chip data for a PWM
217 * @pwm: PWM device
218 *
219 * Returns: A pointer to the chip-private data for the PWM device.
220 */
221void *pwm_get_chip_data(struct pwm_device *pwm)
222{
223 return pwm ? pwm->chip_data : NULL;
224}
225EXPORT_SYMBOL_GPL(pwm_get_chip_data);
226
227static bool pwm_ops_check(const struct pwm_ops *ops)
228{
229 /* driver supports legacy, non-atomic operation */
230 if (ops->config && ops->enable && ops->disable)
231 return true;
232
233 /* driver supports atomic operation */
234 if (ops->apply)
235 return true;
236
237 return false;
238}
239
240/**
241 * pwmchip_add_with_polarity() - register a new PWM chip
242 * @chip: the PWM chip to add
243 * @polarity: initial polarity of PWM channels
244 *
245 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
246 * will be used. The initial polarity for all channels is specified by the
247 * @polarity parameter.
248 *
249 * Returns: 0 on success or a negative error code on failure.
250 */
251int pwmchip_add_with_polarity(struct pwm_chip *chip,
252 enum pwm_polarity polarity)
253{
254 struct pwm_device *pwm;
255 unsigned int i;
256 int ret;
257
258 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
259 return -EINVAL;
260
261 if (!pwm_ops_check(chip->ops))
262 return -EINVAL;
263
264 mutex_lock(&pwm_lock);
265
266 ret = alloc_pwms(chip->base, chip->npwm);
267 if (ret < 0)
268 goto out;
269
270 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
271 if (!chip->pwms) {
272 ret = -ENOMEM;
273 goto out;
274 }
275
276 chip->base = ret;
277
278 for (i = 0; i < chip->npwm; i++) {
279 pwm = &chip->pwms[i];
280
281 pwm->chip = chip;
282 pwm->pwm = chip->base + i;
283 pwm->hwpwm = i;
284 pwm->state.polarity = polarity;
285
286 if (chip->ops->get_state)
287 chip->ops->get_state(chip, pwm, &pwm->state);
288
289 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
290 }
291
292 bitmap_set(allocated_pwms, chip->base, chip->npwm);
293
294 INIT_LIST_HEAD(&chip->list);
295 list_add(&chip->list, &pwm_chips);
296
297 ret = 0;
298
299 if (IS_ENABLED(CONFIG_OF))
300 of_pwmchip_add(chip);
301
302out:
303 mutex_unlock(&pwm_lock);
304
305 if (!ret)
306 pwmchip_sysfs_export(chip);
307
308 return ret;
309}
310EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
311
312/**
313 * pwmchip_add() - register a new PWM chip
314 * @chip: the PWM chip to add
315 *
316 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
317 * will be used. The initial polarity for all channels is normal.
318 *
319 * Returns: 0 on success or a negative error code on failure.
320 */
321int pwmchip_add(struct pwm_chip *chip)
322{
323 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
324}
325EXPORT_SYMBOL_GPL(pwmchip_add);
326
327/**
328 * pwmchip_remove() - remove a PWM chip
329 * @chip: the PWM chip to remove
330 *
331 * Removes a PWM chip. This function may return busy if the PWM chip provides
332 * a PWM device that is still requested.
333 *
334 * Returns: 0 on success or a negative error code on failure.
335 */
336int pwmchip_remove(struct pwm_chip *chip)
337{
338 unsigned int i;
339 int ret = 0;
340
341 pwmchip_sysfs_unexport(chip);
342
343 mutex_lock(&pwm_lock);
344
345 for (i = 0; i < chip->npwm; i++) {
346 struct pwm_device *pwm = &chip->pwms[i];
347
348 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
349 ret = -EBUSY;
350 goto out;
351 }
352 }
353
354 list_del_init(&chip->list);
355
356 if (IS_ENABLED(CONFIG_OF))
357 of_pwmchip_remove(chip);
358
359 free_pwms(chip);
360
361out:
362 mutex_unlock(&pwm_lock);
363 return ret;
364}
365EXPORT_SYMBOL_GPL(pwmchip_remove);
366
367/**
368 * pwm_request() - request a PWM device
369 * @pwm: global PWM device index
370 * @label: PWM device label
371 *
372 * This function is deprecated, use pwm_get() instead.
373 *
374 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
375 * failure.
376 */
377struct pwm_device *pwm_request(int pwm, const char *label)
378{
379 struct pwm_device *dev;
380 int err;
381
382 if (pwm < 0 || pwm >= MAX_PWMS)
383 return ERR_PTR(-EINVAL);
384
385 mutex_lock(&pwm_lock);
386
387 dev = pwm_to_device(pwm);
388 if (!dev) {
389 dev = ERR_PTR(-EPROBE_DEFER);
390 goto out;
391 }
392
393 err = pwm_device_request(dev, label);
394 if (err < 0)
395 dev = ERR_PTR(err);
396
397out:
398 mutex_unlock(&pwm_lock);
399
400 return dev;
401}
402EXPORT_SYMBOL_GPL(pwm_request);
403
404/**
405 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
406 * @chip: PWM chip
407 * @index: per-chip index of the PWM to request
408 * @label: a literal description string of this PWM
409 *
410 * Returns: A pointer to the PWM device at the given index of the given PWM
411 * chip. A negative error code is returned if the index is not valid for the
412 * specified PWM chip or if the PWM device cannot be requested.
413 */
414struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
415 unsigned int index,
416 const char *label)
417{
418 struct pwm_device *pwm;
419 int err;
420
421 if (!chip || index >= chip->npwm)
422 return ERR_PTR(-EINVAL);
423
424 mutex_lock(&pwm_lock);
425 pwm = &chip->pwms[index];
426
427 err = pwm_device_request(pwm, label);
428 if (err < 0)
429 pwm = ERR_PTR(err);
430
431 mutex_unlock(&pwm_lock);
432 return pwm;
433}
434EXPORT_SYMBOL_GPL(pwm_request_from_chip);
435
436/**
437 * pwm_free() - free a PWM device
438 * @pwm: PWM device
439 *
440 * This function is deprecated, use pwm_put() instead.
441 */
442void pwm_free(struct pwm_device *pwm)
443{
444 pwm_put(pwm);
445}
446EXPORT_SYMBOL_GPL(pwm_free);
447
448/**
449 * pwm_apply_state() - atomically apply a new state to a PWM device
450 * @pwm: PWM device
451 * @state: new state to apply
452 */
453int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
454{
455 struct pwm_chip *chip;
456 int err;
457
458 if (!pwm || !state || !state->period ||
459 state->duty_cycle > state->period)
460 return -EINVAL;
461
462 chip = pwm->chip;
463
464 if (state->period == pwm->state.period &&
465 state->duty_cycle == pwm->state.duty_cycle &&
466 state->polarity == pwm->state.polarity &&
467 state->enabled == pwm->state.enabled)
468 return 0;
469
470 if (chip->ops->apply) {
471 err = chip->ops->apply(chip, pwm, state);
472 if (err)
473 return err;
474
475 pwm->state = *state;
476 } else {
477 /*
478 * FIXME: restore the initial state in case of error.
479 */
480 if (state->polarity != pwm->state.polarity) {
481 if (!chip->ops->set_polarity)
482 return -ENOTSUPP;
483
484 /*
485 * Changing the polarity of a running PWM is
486 * only allowed when the PWM driver implements
487 * ->apply().
488 */
489 if (pwm->state.enabled) {
490 chip->ops->disable(chip, pwm);
491 pwm->state.enabled = false;
492 }
493
494 err = chip->ops->set_polarity(chip, pwm,
495 state->polarity);
496 if (err)
497 return err;
498
499 pwm->state.polarity = state->polarity;
500 }
501
502 if (state->period != pwm->state.period ||
503 state->duty_cycle != pwm->state.duty_cycle) {
504 err = chip->ops->config(pwm->chip, pwm,
505 state->duty_cycle,
506 state->period);
507 if (err)
508 return err;
509
510 pwm->state.duty_cycle = state->duty_cycle;
511 pwm->state.period = state->period;
512 }
513
514 if (state->enabled != pwm->state.enabled) {
515 if (state->enabled) {
516 err = chip->ops->enable(chip, pwm);
517 if (err)
518 return err;
519 } else {
520 chip->ops->disable(chip, pwm);
521 }
522
523 pwm->state.enabled = state->enabled;
524 }
525 }
526
527 return 0;
528}
529EXPORT_SYMBOL_GPL(pwm_apply_state);
530
531/**
532 * pwm_capture() - capture and report a PWM signal
533 * @pwm: PWM device
534 * @result: structure to fill with capture result
535 * @timeout: time to wait, in milliseconds, before giving up on capture
536 *
537 * Returns: 0 on success or a negative error code on failure.
538 */
539int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
540 unsigned long timeout)
541{
542 int err;
543
544 if (!pwm || !pwm->chip->ops)
545 return -EINVAL;
546
547 if (!pwm->chip->ops->capture)
548 return -ENOSYS;
549
550 mutex_lock(&pwm_lock);
551 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
552 mutex_unlock(&pwm_lock);
553
554 return err;
555}
556EXPORT_SYMBOL_GPL(pwm_capture);
557
558/**
559 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
560 * @pwm: PWM device
561 *
562 * This function will adjust the PWM config to the PWM arguments provided
563 * by the DT or PWM lookup table. This is particularly useful to adapt
564 * the bootloader config to the Linux one.
565 */
566int pwm_adjust_config(struct pwm_device *pwm)
567{
568 struct pwm_state state;
569 struct pwm_args pargs;
570
571 pwm_get_args(pwm, &pargs);
572 pwm_get_state(pwm, &state);
573
574 /*
575 * If the current period is zero it means that either the PWM driver
576 * does not support initial state retrieval or the PWM has not yet
577 * been configured.
578 *
579 * In either case, we setup the new period and polarity, and assign a
580 * duty cycle of 0.
581 */
582 if (!state.period) {
583 state.duty_cycle = 0;
584 state.period = pargs.period;
585 state.polarity = pargs.polarity;
586
587 return pwm_apply_state(pwm, &state);
588 }
589
590 /*
591 * Adjust the PWM duty cycle/period based on the period value provided
592 * in PWM args.
593 */
594 if (pargs.period != state.period) {
595 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
596
597 do_div(dutycycle, state.period);
598 state.duty_cycle = dutycycle;
599 state.period = pargs.period;
600 }
601
602 /*
603 * If the polarity changed, we should also change the duty cycle.
604 */
605 if (pargs.polarity != state.polarity) {
606 state.polarity = pargs.polarity;
607 state.duty_cycle = state.period - state.duty_cycle;
608 }
609
610 return pwm_apply_state(pwm, &state);
611}
612EXPORT_SYMBOL_GPL(pwm_adjust_config);
613
614static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
615{
616 struct pwm_chip *chip;
617
618 mutex_lock(&pwm_lock);
619
620 list_for_each_entry(chip, &pwm_chips, list)
621 if (chip->dev && chip->dev->of_node == np) {
622 mutex_unlock(&pwm_lock);
623 return chip;
624 }
625
626 mutex_unlock(&pwm_lock);
627
628 return ERR_PTR(-EPROBE_DEFER);
629}
630
631static struct device_link *pwm_device_link_add(struct device *dev,
632 struct pwm_device *pwm)
633{
634 struct device_link *dl;
635
636 if (!dev) {
637 /*
638 * No device for the PWM consumer has been provided. It may
639 * impact the PM sequence ordering: the PWM supplier may get
640 * suspended before the consumer.
641 */
642 dev_warn(pwm->chip->dev,
643 "No consumer device specified to create a link to\n");
644 return NULL;
645 }
646
647 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
648 if (!dl) {
649 dev_err(dev, "failed to create device link to %s\n",
650 dev_name(pwm->chip->dev));
651 return ERR_PTR(-EINVAL);
652 }
653
654 return dl;
655}
656
657/**
658 * of_pwm_get() - request a PWM via the PWM framework
659 * @dev: device for PWM consumer
660 * @np: device node to get the PWM from
661 * @con_id: consumer name
662 *
663 * Returns the PWM device parsed from the phandle and index specified in the
664 * "pwms" property of a device tree node or a negative error-code on failure.
665 * Values parsed from the device tree are stored in the returned PWM device
666 * object.
667 *
668 * If con_id is NULL, the first PWM device listed in the "pwms" property will
669 * be requested. Otherwise the "pwm-names" property is used to do a reverse
670 * lookup of the PWM index. This also means that the "pwm-names" property
671 * becomes mandatory for devices that look up the PWM device via the con_id
672 * parameter.
673 *
674 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
675 * error code on failure.
676 */
677struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
678 const char *con_id)
679{
680 struct pwm_device *pwm = NULL;
681 struct of_phandle_args args;
682 struct device_link *dl;
683 struct pwm_chip *pc;
684 int index = 0;
685 int err;
686
687 if (con_id) {
688 index = of_property_match_string(np, "pwm-names", con_id);
689 if (index < 0)
690 return ERR_PTR(index);
691 }
692
693 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
694 &args);
695 if (err) {
696 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
697 return ERR_PTR(err);
698 }
699
700 pc = of_node_to_pwmchip(args.np);
701 if (IS_ERR(pc)) {
702 if (PTR_ERR(pc) != -EPROBE_DEFER)
703 pr_err("%s(): PWM chip not found\n", __func__);
704
705 pwm = ERR_CAST(pc);
706 goto put;
707 }
708
709 pwm = pc->of_xlate(pc, &args);
710 if (IS_ERR(pwm))
711 goto put;
712
713 dl = pwm_device_link_add(dev, pwm);
714 if (IS_ERR(dl)) {
715 /* of_xlate ended up calling pwm_request_from_chip() */
716 pwm_free(pwm);
717 pwm = ERR_CAST(dl);
718 goto put;
719 }
720
721 /*
722 * If a consumer name was not given, try to look it up from the
723 * "pwm-names" property if it exists. Otherwise use the name of
724 * the user device node.
725 */
726 if (!con_id) {
727 err = of_property_read_string_index(np, "pwm-names", index,
728 &con_id);
729 if (err < 0)
730 con_id = np->name;
731 }
732
733 pwm->label = con_id;
734
735put:
736 of_node_put(args.np);
737
738 return pwm;
739}
740EXPORT_SYMBOL_GPL(of_pwm_get);
741
742#if IS_ENABLED(CONFIG_ACPI)
743static struct pwm_chip *device_to_pwmchip(struct device *dev)
744{
745 struct pwm_chip *chip;
746
747 mutex_lock(&pwm_lock);
748
749 list_for_each_entry(chip, &pwm_chips, list) {
750 struct acpi_device *adev = ACPI_COMPANION(chip->dev);
751
752 if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
753 mutex_unlock(&pwm_lock);
754 return chip;
755 }
756 }
757
758 mutex_unlock(&pwm_lock);
759
760 return ERR_PTR(-EPROBE_DEFER);
761}
762#endif
763
764/**
765 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
766 * @fwnode: firmware node to get the "pwm" property from
767 *
768 * Returns the PWM device parsed from the fwnode and index specified in the
769 * "pwms" property or a negative error-code on failure.
770 * Values parsed from the device tree are stored in the returned PWM device
771 * object.
772 *
773 * This is analogous to of_pwm_get() except con_id is not yet supported.
774 * ACPI entries must look like
775 * Package () {"pwms", Package ()
776 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
777 *
778 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
779 * error code on failure.
780 */
781static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
782{
783 struct pwm_device *pwm = ERR_PTR(-ENODEV);
784#if IS_ENABLED(CONFIG_ACPI)
785 struct fwnode_reference_args args;
786 struct acpi_device *acpi;
787 struct pwm_chip *chip;
788 int ret;
789
790 memset(&args, 0, sizeof(args));
791
792 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
793 if (ret < 0)
794 return ERR_PTR(ret);
795
796 acpi = to_acpi_device_node(args.fwnode);
797 if (!acpi)
798 return ERR_PTR(-EINVAL);
799
800 if (args.nargs < 2)
801 return ERR_PTR(-EPROTO);
802
803 chip = device_to_pwmchip(&acpi->dev);
804 if (IS_ERR(chip))
805 return ERR_CAST(chip);
806
807 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
808 if (IS_ERR(pwm))
809 return pwm;
810
811 pwm->args.period = args.args[1];
812 pwm->args.polarity = PWM_POLARITY_NORMAL;
813
814 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
815 pwm->args.polarity = PWM_POLARITY_INVERSED;
816#endif
817
818 return pwm;
819}
820
821/**
822 * pwm_add_table() - register PWM device consumers
823 * @table: array of consumers to register
824 * @num: number of consumers in table
825 */
826void pwm_add_table(struct pwm_lookup *table, size_t num)
827{
828 mutex_lock(&pwm_lookup_lock);
829
830 while (num--) {
831 list_add_tail(&table->list, &pwm_lookup_list);
832 table++;
833 }
834
835 mutex_unlock(&pwm_lookup_lock);
836}
837
838/**
839 * pwm_remove_table() - unregister PWM device consumers
840 * @table: array of consumers to unregister
841 * @num: number of consumers in table
842 */
843void pwm_remove_table(struct pwm_lookup *table, size_t num)
844{
845 mutex_lock(&pwm_lookup_lock);
846
847 while (num--) {
848 list_del(&table->list);
849 table++;
850 }
851
852 mutex_unlock(&pwm_lookup_lock);
853}
854
855/**
856 * pwm_get() - look up and request a PWM device
857 * @dev: device for PWM consumer
858 * @con_id: consumer name
859 *
860 * Lookup is first attempted using DT. If the device was not instantiated from
861 * a device tree, a PWM chip and a relative index is looked up via a table
862 * supplied by board setup code (see pwm_add_table()).
863 *
864 * Once a PWM chip has been found the specified PWM device will be requested
865 * and is ready to be used.
866 *
867 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
868 * error code on failure.
869 */
870struct pwm_device *pwm_get(struct device *dev, const char *con_id)
871{
872 const char *dev_id = dev ? dev_name(dev) : NULL;
873 struct pwm_device *pwm;
874 struct pwm_chip *chip;
875 struct device_link *dl;
876 unsigned int best = 0;
877 struct pwm_lookup *p, *chosen = NULL;
878 unsigned int match;
879 int err;
880
881 /* look up via DT first */
882 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
883 return of_pwm_get(dev, dev->of_node, con_id);
884
885 /* then lookup via ACPI */
886 if (dev && is_acpi_node(dev->fwnode)) {
887 pwm = acpi_pwm_get(dev->fwnode);
888 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
889 return pwm;
890 }
891
892 /*
893 * We look up the provider in the static table typically provided by
894 * board setup code. We first try to lookup the consumer device by
895 * name. If the consumer device was passed in as NULL or if no match
896 * was found, we try to find the consumer by directly looking it up
897 * by name.
898 *
899 * If a match is found, the provider PWM chip is looked up by name
900 * and a PWM device is requested using the PWM device per-chip index.
901 *
902 * The lookup algorithm was shamelessly taken from the clock
903 * framework:
904 *
905 * We do slightly fuzzy matching here:
906 * An entry with a NULL ID is assumed to be a wildcard.
907 * If an entry has a device ID, it must match
908 * If an entry has a connection ID, it must match
909 * Then we take the most specific entry - with the following order
910 * of precedence: dev+con > dev only > con only.
911 */
912 mutex_lock(&pwm_lookup_lock);
913
914 list_for_each_entry(p, &pwm_lookup_list, list) {
915 match = 0;
916
917 if (p->dev_id) {
918 if (!dev_id || strcmp(p->dev_id, dev_id))
919 continue;
920
921 match += 2;
922 }
923
924 if (p->con_id) {
925 if (!con_id || strcmp(p->con_id, con_id))
926 continue;
927
928 match += 1;
929 }
930
931 if (match > best) {
932 chosen = p;
933
934 if (match != 3)
935 best = match;
936 else
937 break;
938 }
939 }
940
941 mutex_unlock(&pwm_lookup_lock);
942
943 if (!chosen)
944 return ERR_PTR(-ENODEV);
945
946 chip = pwmchip_find_by_name(chosen->provider);
947
948 /*
949 * If the lookup entry specifies a module, load the module and retry
950 * the PWM chip lookup. This can be used to work around driver load
951 * ordering issues if driver's can't be made to properly support the
952 * deferred probe mechanism.
953 */
954 if (!chip && chosen->module) {
955 err = request_module(chosen->module);
956 if (err == 0)
957 chip = pwmchip_find_by_name(chosen->provider);
958 }
959
960 if (!chip)
961 return ERR_PTR(-EPROBE_DEFER);
962
963 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
964 if (IS_ERR(pwm))
965 return pwm;
966
967 dl = pwm_device_link_add(dev, pwm);
968 if (IS_ERR(dl)) {
969 pwm_free(pwm);
970 return ERR_CAST(dl);
971 }
972
973 pwm->args.period = chosen->period;
974 pwm->args.polarity = chosen->polarity;
975
976 return pwm;
977}
978EXPORT_SYMBOL_GPL(pwm_get);
979
980/**
981 * pwm_put() - release a PWM device
982 * @pwm: PWM device
983 */
984void pwm_put(struct pwm_device *pwm)
985{
986 if (!pwm)
987 return;
988
989 mutex_lock(&pwm_lock);
990
991 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
992 pr_warn("PWM device already freed\n");
993 goto out;
994 }
995
996 if (pwm->chip->ops->free)
997 pwm->chip->ops->free(pwm->chip, pwm);
998
999 pwm_set_chip_data(pwm, NULL);
1000 pwm->label = NULL;
1001
1002 module_put(pwm->chip->ops->owner);
1003out:
1004 mutex_unlock(&pwm_lock);
1005}
1006EXPORT_SYMBOL_GPL(pwm_put);
1007
1008static void devm_pwm_release(struct device *dev, void *res)
1009{
1010 pwm_put(*(struct pwm_device **)res);
1011}
1012
1013/**
1014 * devm_pwm_get() - resource managed pwm_get()
1015 * @dev: device for PWM consumer
1016 * @con_id: consumer name
1017 *
1018 * This function performs like pwm_get() but the acquired PWM device will
1019 * automatically be released on driver detach.
1020 *
1021 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1022 * error code on failure.
1023 */
1024struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1025{
1026 struct pwm_device **ptr, *pwm;
1027
1028 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1029 if (!ptr)
1030 return ERR_PTR(-ENOMEM);
1031
1032 pwm = pwm_get(dev, con_id);
1033 if (!IS_ERR(pwm)) {
1034 *ptr = pwm;
1035 devres_add(dev, ptr);
1036 } else {
1037 devres_free(ptr);
1038 }
1039
1040 return pwm;
1041}
1042EXPORT_SYMBOL_GPL(devm_pwm_get);
1043
1044/**
1045 * devm_of_pwm_get() - resource managed of_pwm_get()
1046 * @dev: device for PWM consumer
1047 * @np: device node to get the PWM from
1048 * @con_id: consumer name
1049 *
1050 * This function performs like of_pwm_get() but the acquired PWM device will
1051 * automatically be released on driver detach.
1052 *
1053 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1054 * error code on failure.
1055 */
1056struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
1057 const char *con_id)
1058{
1059 struct pwm_device **ptr, *pwm;
1060
1061 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1062 if (!ptr)
1063 return ERR_PTR(-ENOMEM);
1064
1065 pwm = of_pwm_get(dev, np, con_id);
1066 if (!IS_ERR(pwm)) {
1067 *ptr = pwm;
1068 devres_add(dev, ptr);
1069 } else {
1070 devres_free(ptr);
1071 }
1072
1073 return pwm;
1074}
1075EXPORT_SYMBOL_GPL(devm_of_pwm_get);
1076
1077/**
1078 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1079 * @dev: device for PWM consumer
1080 * @fwnode: firmware node to get the PWM from
1081 * @con_id: consumer name
1082 *
1083 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1084 * acpi_pwm_get() for a detailed description.
1085 *
1086 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1087 * error code on failure.
1088 */
1089struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1090 struct fwnode_handle *fwnode,
1091 const char *con_id)
1092{
1093 struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV);
1094
1095 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1096 if (!ptr)
1097 return ERR_PTR(-ENOMEM);
1098
1099 if (is_of_node(fwnode))
1100 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1101 else if (is_acpi_node(fwnode))
1102 pwm = acpi_pwm_get(fwnode);
1103
1104 if (!IS_ERR(pwm)) {
1105 *ptr = pwm;
1106 devres_add(dev, ptr);
1107 } else {
1108 devres_free(ptr);
1109 }
1110
1111 return pwm;
1112}
1113EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1114
1115static int devm_pwm_match(struct device *dev, void *res, void *data)
1116{
1117 struct pwm_device **p = res;
1118
1119 if (WARN_ON(!p || !*p))
1120 return 0;
1121
1122 return *p == data;
1123}
1124
1125/**
1126 * devm_pwm_put() - resource managed pwm_put()
1127 * @dev: device for PWM consumer
1128 * @pwm: PWM device
1129 *
1130 * Release a PWM previously allocated using devm_pwm_get(). Calling this
1131 * function is usually not needed because devm-allocated resources are
1132 * automatically released on driver detach.
1133 */
1134void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
1135{
1136 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
1137}
1138EXPORT_SYMBOL_GPL(devm_pwm_put);
1139
1140#ifdef CONFIG_DEBUG_FS
1141static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1142{
1143 unsigned int i;
1144
1145 for (i = 0; i < chip->npwm; i++) {
1146 struct pwm_device *pwm = &chip->pwms[i];
1147 struct pwm_state state;
1148
1149 pwm_get_state(pwm, &state);
1150
1151 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1152
1153 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1154 seq_puts(s, " requested");
1155
1156 if (state.enabled)
1157 seq_puts(s, " enabled");
1158
1159 seq_printf(s, " period: %u ns", state.period);
1160 seq_printf(s, " duty: %u ns", state.duty_cycle);
1161 seq_printf(s, " polarity: %s",
1162 state.polarity ? "inverse" : "normal");
1163
1164 seq_puts(s, "\n");
1165 }
1166}
1167
1168static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1169{
1170 mutex_lock(&pwm_lock);
1171 s->private = "";
1172
1173 return seq_list_start(&pwm_chips, *pos);
1174}
1175
1176static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1177{
1178 s->private = "\n";
1179
1180 return seq_list_next(v, &pwm_chips, pos);
1181}
1182
1183static void pwm_seq_stop(struct seq_file *s, void *v)
1184{
1185 mutex_unlock(&pwm_lock);
1186}
1187
1188static int pwm_seq_show(struct seq_file *s, void *v)
1189{
1190 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1191
1192 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1193 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1194 dev_name(chip->dev), chip->npwm,
1195 (chip->npwm != 1) ? "s" : "");
1196
1197 pwm_dbg_show(chip, s);
1198
1199 return 0;
1200}
1201
1202static const struct seq_operations pwm_seq_ops = {
1203 .start = pwm_seq_start,
1204 .next = pwm_seq_next,
1205 .stop = pwm_seq_stop,
1206 .show = pwm_seq_show,
1207};
1208
1209static int pwm_seq_open(struct inode *inode, struct file *file)
1210{
1211 return seq_open(file, &pwm_seq_ops);
1212}
1213
1214static const struct file_operations pwm_debugfs_ops = {
1215 .owner = THIS_MODULE,
1216 .open = pwm_seq_open,
1217 .read = seq_read,
1218 .llseek = seq_lseek,
1219 .release = seq_release,
1220};
1221
1222static int __init pwm_debugfs_init(void)
1223{
1224 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1225 &pwm_debugfs_ops);
1226
1227 return 0;
1228}
1229subsys_initcall(pwm_debugfs_init);
1230#endif /* CONFIG_DEBUG_FS */