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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/idr.h>
12#include <linux/of.h>
13#include <linux/pwm.h>
14#include <linux/list.h>
15#include <linux/mutex.h>
16#include <linux/err.h>
17#include <linux/slab.h>
18#include <linux/device.h>
19#include <linux/debugfs.h>
20#include <linux/seq_file.h>
21
22#include <dt-bindings/pwm/pwm.h>
23
24#define CREATE_TRACE_POINTS
25#include <trace/events/pwm.h>
26
27static DEFINE_MUTEX(pwm_lookup_lock);
28static LIST_HEAD(pwm_lookup_list);
29
30/* protects access to pwm_chips */
31static DEFINE_MUTEX(pwm_lock);
32
33static DEFINE_IDR(pwm_chips);
34
35static struct pwm_chip *pwmchip_find_by_name(const char *name)
36{
37 struct pwm_chip *chip;
38 unsigned long id, tmp;
39
40 if (!name)
41 return NULL;
42
43 mutex_lock(&pwm_lock);
44
45 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
46 const char *chip_name = dev_name(chip->dev);
47
48 if (chip_name && strcmp(chip_name, name) == 0) {
49 mutex_unlock(&pwm_lock);
50 return chip;
51 }
52 }
53
54 mutex_unlock(&pwm_lock);
55
56 return NULL;
57}
58
59static int pwm_device_request(struct pwm_device *pwm, const char *label)
60{
61 int err;
62 struct pwm_chip *chip = pwm->chip;
63 const struct pwm_ops *ops = chip->ops;
64
65 if (test_bit(PWMF_REQUESTED, &pwm->flags))
66 return -EBUSY;
67
68 if (!try_module_get(chip->owner))
69 return -ENODEV;
70
71 if (ops->request) {
72 err = ops->request(chip, pwm);
73 if (err) {
74 module_put(chip->owner);
75 return err;
76 }
77 }
78
79 if (ops->get_state) {
80 /*
81 * Zero-initialize state because most drivers are unaware of
82 * .usage_power. The other members of state are supposed to be
83 * set by lowlevel drivers. We still initialize the whole
84 * structure for simplicity even though this might paper over
85 * faulty implementations of .get_state().
86 */
87 struct pwm_state state = { 0, };
88
89 err = ops->get_state(chip, pwm, &state);
90 trace_pwm_get(pwm, &state, err);
91
92 if (!err)
93 pwm->state = state;
94
95 if (IS_ENABLED(CONFIG_PWM_DEBUG))
96 pwm->last = pwm->state;
97 }
98
99 set_bit(PWMF_REQUESTED, &pwm->flags);
100 pwm->label = label;
101
102 return 0;
103}
104
105struct pwm_device *
106of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
107{
108 struct pwm_device *pwm;
109
110 if (chip->of_pwm_n_cells < 2)
111 return ERR_PTR(-EINVAL);
112
113 /* flags in the third cell are optional */
114 if (args->args_count < 2)
115 return ERR_PTR(-EINVAL);
116
117 if (args->args[0] >= chip->npwm)
118 return ERR_PTR(-EINVAL);
119
120 pwm = pwm_request_from_chip(chip, args->args[0], NULL);
121 if (IS_ERR(pwm))
122 return pwm;
123
124 pwm->args.period = args->args[1];
125 pwm->args.polarity = PWM_POLARITY_NORMAL;
126
127 if (chip->of_pwm_n_cells >= 3) {
128 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
129 pwm->args.polarity = PWM_POLARITY_INVERSED;
130 }
131
132 return pwm;
133}
134EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
135
136struct pwm_device *
137of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
138{
139 struct pwm_device *pwm;
140
141 if (chip->of_pwm_n_cells < 1)
142 return ERR_PTR(-EINVAL);
143
144 /* validate that one cell is specified, optionally with flags */
145 if (args->args_count != 1 && args->args_count != 2)
146 return ERR_PTR(-EINVAL);
147
148 pwm = pwm_request_from_chip(chip, 0, NULL);
149 if (IS_ERR(pwm))
150 return pwm;
151
152 pwm->args.period = args->args[0];
153 pwm->args.polarity = PWM_POLARITY_NORMAL;
154
155 if (args->args_count == 2 && args->args[1] & PWM_POLARITY_INVERTED)
156 pwm->args.polarity = PWM_POLARITY_INVERSED;
157
158 return pwm;
159}
160EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
161
162static void of_pwmchip_add(struct pwm_chip *chip)
163{
164 if (!chip->dev || !chip->dev->of_node)
165 return;
166
167 if (!chip->of_xlate) {
168 u32 pwm_cells;
169
170 if (of_property_read_u32(chip->dev->of_node, "#pwm-cells",
171 &pwm_cells))
172 pwm_cells = 2;
173
174 chip->of_xlate = of_pwm_xlate_with_flags;
175 chip->of_pwm_n_cells = pwm_cells;
176 }
177
178 of_node_get(chip->dev->of_node);
179}
180
181static void of_pwmchip_remove(struct pwm_chip *chip)
182{
183 if (chip->dev)
184 of_node_put(chip->dev->of_node);
185}
186
187static bool pwm_ops_check(const struct pwm_chip *chip)
188{
189 const struct pwm_ops *ops = chip->ops;
190
191 if (!ops->apply)
192 return false;
193
194 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
195 dev_warn(chip->dev,
196 "Please implement the .get_state() callback\n");
197
198 return true;
199}
200
201/**
202 * __pwmchip_add() - register a new PWM chip
203 * @chip: the PWM chip to add
204 * @owner: reference to the module providing the chip.
205 *
206 * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
207 * pwmchip_add wrapper to do this right.
208 *
209 * Returns: 0 on success or a negative error code on failure.
210 */
211int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
212{
213 unsigned int i;
214 int ret;
215
216 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
217 return -EINVAL;
218
219 if (!pwm_ops_check(chip))
220 return -EINVAL;
221
222 chip->owner = owner;
223
224 chip->pwms = kcalloc(chip->npwm, sizeof(*chip->pwms), GFP_KERNEL);
225 if (!chip->pwms)
226 return -ENOMEM;
227
228 mutex_lock(&pwm_lock);
229
230 ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
231 if (ret < 0) {
232 mutex_unlock(&pwm_lock);
233 kfree(chip->pwms);
234 return ret;
235 }
236
237 chip->id = ret;
238
239 for (i = 0; i < chip->npwm; i++) {
240 struct pwm_device *pwm = &chip->pwms[i];
241
242 pwm->chip = chip;
243 pwm->hwpwm = i;
244 }
245
246 mutex_unlock(&pwm_lock);
247
248 if (IS_ENABLED(CONFIG_OF))
249 of_pwmchip_add(chip);
250
251 pwmchip_sysfs_export(chip);
252
253 return 0;
254}
255EXPORT_SYMBOL_GPL(__pwmchip_add);
256
257/**
258 * pwmchip_remove() - remove a PWM chip
259 * @chip: the PWM chip to remove
260 *
261 * Removes a PWM chip.
262 */
263void pwmchip_remove(struct pwm_chip *chip)
264{
265 pwmchip_sysfs_unexport(chip);
266
267 if (IS_ENABLED(CONFIG_OF))
268 of_pwmchip_remove(chip);
269
270 mutex_lock(&pwm_lock);
271
272 idr_remove(&pwm_chips, chip->id);
273
274 mutex_unlock(&pwm_lock);
275
276 kfree(chip->pwms);
277}
278EXPORT_SYMBOL_GPL(pwmchip_remove);
279
280static void devm_pwmchip_remove(void *data)
281{
282 struct pwm_chip *chip = data;
283
284 pwmchip_remove(chip);
285}
286
287int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
288{
289 int ret;
290
291 ret = __pwmchip_add(chip, owner);
292 if (ret)
293 return ret;
294
295 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
296}
297EXPORT_SYMBOL_GPL(__devm_pwmchip_add);
298
299/**
300 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
301 * @chip: PWM chip
302 * @index: per-chip index of the PWM to request
303 * @label: a literal description string of this PWM
304 *
305 * Returns: A pointer to the PWM device at the given index of the given PWM
306 * chip. A negative error code is returned if the index is not valid for the
307 * specified PWM chip or if the PWM device cannot be requested.
308 */
309struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
310 unsigned int index,
311 const char *label)
312{
313 struct pwm_device *pwm;
314 int err;
315
316 if (!chip || index >= chip->npwm)
317 return ERR_PTR(-EINVAL);
318
319 mutex_lock(&pwm_lock);
320 pwm = &chip->pwms[index];
321
322 err = pwm_device_request(pwm, label);
323 if (err < 0)
324 pwm = ERR_PTR(err);
325
326 mutex_unlock(&pwm_lock);
327 return pwm;
328}
329EXPORT_SYMBOL_GPL(pwm_request_from_chip);
330
331static void pwm_apply_debug(struct pwm_device *pwm,
332 const struct pwm_state *state)
333{
334 struct pwm_state *last = &pwm->last;
335 struct pwm_chip *chip = pwm->chip;
336 struct pwm_state s1 = { 0 }, s2 = { 0 };
337 int err;
338
339 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
340 return;
341
342 /* No reasonable diagnosis possible without .get_state() */
343 if (!chip->ops->get_state)
344 return;
345
346 /*
347 * *state was just applied. Read out the hardware state and do some
348 * checks.
349 */
350
351 err = chip->ops->get_state(chip, pwm, &s1);
352 trace_pwm_get(pwm, &s1, err);
353 if (err)
354 /* If that failed there isn't much to debug */
355 return;
356
357 /*
358 * The lowlevel driver either ignored .polarity (which is a bug) or as
359 * best effort inverted .polarity and fixed .duty_cycle respectively.
360 * Undo this inversion and fixup for further tests.
361 */
362 if (s1.enabled && s1.polarity != state->polarity) {
363 s2.polarity = state->polarity;
364 s2.duty_cycle = s1.period - s1.duty_cycle;
365 s2.period = s1.period;
366 s2.enabled = s1.enabled;
367 } else {
368 s2 = s1;
369 }
370
371 if (s2.polarity != state->polarity &&
372 state->duty_cycle < state->period)
373 dev_warn(chip->dev, ".apply ignored .polarity\n");
374
375 if (state->enabled &&
376 last->polarity == state->polarity &&
377 last->period > s2.period &&
378 last->period <= state->period)
379 dev_warn(chip->dev,
380 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
381 state->period, s2.period, last->period);
382
383 if (state->enabled && state->period < s2.period)
384 dev_warn(chip->dev,
385 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
386 state->period, s2.period);
387
388 if (state->enabled &&
389 last->polarity == state->polarity &&
390 last->period == s2.period &&
391 last->duty_cycle > s2.duty_cycle &&
392 last->duty_cycle <= state->duty_cycle)
393 dev_warn(chip->dev,
394 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
395 state->duty_cycle, state->period,
396 s2.duty_cycle, s2.period,
397 last->duty_cycle, last->period);
398
399 if (state->enabled && state->duty_cycle < s2.duty_cycle)
400 dev_warn(chip->dev,
401 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
402 state->duty_cycle, state->period,
403 s2.duty_cycle, s2.period);
404
405 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
406 dev_warn(chip->dev,
407 "requested disabled, but yielded enabled with duty > 0\n");
408
409 /* reapply the state that the driver reported being configured. */
410 err = chip->ops->apply(chip, pwm, &s1);
411 trace_pwm_apply(pwm, &s1, err);
412 if (err) {
413 *last = s1;
414 dev_err(chip->dev, "failed to reapply current setting\n");
415 return;
416 }
417
418 *last = (struct pwm_state){ 0 };
419 err = chip->ops->get_state(chip, pwm, last);
420 trace_pwm_get(pwm, last, err);
421 if (err)
422 return;
423
424 /* reapplication of the current state should give an exact match */
425 if (s1.enabled != last->enabled ||
426 s1.polarity != last->polarity ||
427 (s1.enabled && s1.period != last->period) ||
428 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
429 dev_err(chip->dev,
430 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
431 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
432 last->enabled, last->polarity, last->duty_cycle,
433 last->period);
434 }
435}
436
437/**
438 * __pwm_apply() - atomically apply a new state to a PWM device
439 * @pwm: PWM device
440 * @state: new state to apply
441 */
442static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
443{
444 struct pwm_chip *chip;
445 int err;
446
447 if (!pwm || !state || !state->period ||
448 state->duty_cycle > state->period)
449 return -EINVAL;
450
451 chip = pwm->chip;
452
453 if (state->period == pwm->state.period &&
454 state->duty_cycle == pwm->state.duty_cycle &&
455 state->polarity == pwm->state.polarity &&
456 state->enabled == pwm->state.enabled &&
457 state->usage_power == pwm->state.usage_power)
458 return 0;
459
460 err = chip->ops->apply(chip, pwm, state);
461 trace_pwm_apply(pwm, state, err);
462 if (err)
463 return err;
464
465 pwm->state = *state;
466
467 /*
468 * only do this after pwm->state was applied as some
469 * implementations of .get_state depend on this
470 */
471 pwm_apply_debug(pwm, state);
472
473 return 0;
474}
475
476/**
477 * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
478 * Cannot be used in atomic context.
479 * @pwm: PWM device
480 * @state: new state to apply
481 */
482int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
483{
484 int err;
485
486 /*
487 * Some lowlevel driver's implementations of .apply() make use of
488 * mutexes, also with some drivers only returning when the new
489 * configuration is active calling pwm_apply_might_sleep() from atomic context
490 * is a bad idea. So make it explicit that calling this function might
491 * sleep.
492 */
493 might_sleep();
494
495 if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
496 /*
497 * Catch any drivers that have been marked as atomic but
498 * that will sleep anyway.
499 */
500 non_block_start();
501 err = __pwm_apply(pwm, state);
502 non_block_end();
503 } else {
504 err = __pwm_apply(pwm, state);
505 }
506
507 return err;
508}
509EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);
510
511/**
512 * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
513 * Not all PWM devices support this function, check with pwm_might_sleep().
514 * @pwm: PWM device
515 * @state: new state to apply
516 */
517int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
518{
519 WARN_ONCE(!pwm->chip->atomic,
520 "sleeping PWM driver used in atomic context\n");
521
522 return __pwm_apply(pwm, state);
523}
524EXPORT_SYMBOL_GPL(pwm_apply_atomic);
525
526/**
527 * pwm_capture() - capture and report a PWM signal
528 * @pwm: PWM device
529 * @result: structure to fill with capture result
530 * @timeout: time to wait, in milliseconds, before giving up on capture
531 *
532 * Returns: 0 on success or a negative error code on failure.
533 */
534int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
535 unsigned long timeout)
536{
537 int err;
538
539 if (!pwm || !pwm->chip->ops)
540 return -EINVAL;
541
542 if (!pwm->chip->ops->capture)
543 return -ENOSYS;
544
545 mutex_lock(&pwm_lock);
546 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
547 mutex_unlock(&pwm_lock);
548
549 return err;
550}
551EXPORT_SYMBOL_GPL(pwm_capture);
552
553/**
554 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
555 * @pwm: PWM device
556 *
557 * This function will adjust the PWM config to the PWM arguments provided
558 * by the DT or PWM lookup table. This is particularly useful to adapt
559 * the bootloader config to the Linux one.
560 */
561int pwm_adjust_config(struct pwm_device *pwm)
562{
563 struct pwm_state state;
564 struct pwm_args pargs;
565
566 pwm_get_args(pwm, &pargs);
567 pwm_get_state(pwm, &state);
568
569 /*
570 * If the current period is zero it means that either the PWM driver
571 * does not support initial state retrieval or the PWM has not yet
572 * been configured.
573 *
574 * In either case, we setup the new period and polarity, and assign a
575 * duty cycle of 0.
576 */
577 if (!state.period) {
578 state.duty_cycle = 0;
579 state.period = pargs.period;
580 state.polarity = pargs.polarity;
581
582 return pwm_apply_might_sleep(pwm, &state);
583 }
584
585 /*
586 * Adjust the PWM duty cycle/period based on the period value provided
587 * in PWM args.
588 */
589 if (pargs.period != state.period) {
590 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
591
592 do_div(dutycycle, state.period);
593 state.duty_cycle = dutycycle;
594 state.period = pargs.period;
595 }
596
597 /*
598 * If the polarity changed, we should also change the duty cycle.
599 */
600 if (pargs.polarity != state.polarity) {
601 state.polarity = pargs.polarity;
602 state.duty_cycle = state.period - state.duty_cycle;
603 }
604
605 return pwm_apply_might_sleep(pwm, &state);
606}
607EXPORT_SYMBOL_GPL(pwm_adjust_config);
608
609static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
610{
611 struct pwm_chip *chip;
612 unsigned long id, tmp;
613
614 mutex_lock(&pwm_lock);
615
616 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
617 if (chip->dev && device_match_fwnode(chip->dev, fwnode)) {
618 mutex_unlock(&pwm_lock);
619 return chip;
620 }
621
622 mutex_unlock(&pwm_lock);
623
624 return ERR_PTR(-EPROBE_DEFER);
625}
626
627static struct device_link *pwm_device_link_add(struct device *dev,
628 struct pwm_device *pwm)
629{
630 struct device_link *dl;
631
632 if (!dev) {
633 /*
634 * No device for the PWM consumer has been provided. It may
635 * impact the PM sequence ordering: the PWM supplier may get
636 * suspended before the consumer.
637 */
638 dev_warn(pwm->chip->dev,
639 "No consumer device specified to create a link to\n");
640 return NULL;
641 }
642
643 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
644 if (!dl) {
645 dev_err(dev, "failed to create device link to %s\n",
646 dev_name(pwm->chip->dev));
647 return ERR_PTR(-EINVAL);
648 }
649
650 return dl;
651}
652
653/**
654 * of_pwm_get() - request a PWM via the PWM framework
655 * @dev: device for PWM consumer
656 * @np: device node to get the PWM from
657 * @con_id: consumer name
658 *
659 * Returns the PWM device parsed from the phandle and index specified in the
660 * "pwms" property of a device tree node or a negative error-code on failure.
661 * Values parsed from the device tree are stored in the returned PWM device
662 * object.
663 *
664 * If con_id is NULL, the first PWM device listed in the "pwms" property will
665 * be requested. Otherwise the "pwm-names" property is used to do a reverse
666 * lookup of the PWM index. This also means that the "pwm-names" property
667 * becomes mandatory for devices that look up the PWM device via the con_id
668 * parameter.
669 *
670 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
671 * error code on failure.
672 */
673static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
674 const char *con_id)
675{
676 struct pwm_device *pwm = NULL;
677 struct of_phandle_args args;
678 struct device_link *dl;
679 struct pwm_chip *chip;
680 int index = 0;
681 int err;
682
683 if (con_id) {
684 index = of_property_match_string(np, "pwm-names", con_id);
685 if (index < 0)
686 return ERR_PTR(index);
687 }
688
689 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
690 &args);
691 if (err) {
692 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
693 return ERR_PTR(err);
694 }
695
696 chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
697 if (IS_ERR(chip)) {
698 if (PTR_ERR(chip) != -EPROBE_DEFER)
699 pr_err("%s(): PWM chip not found\n", __func__);
700
701 pwm = ERR_CAST(chip);
702 goto put;
703 }
704
705 pwm = chip->of_xlate(chip, &args);
706 if (IS_ERR(pwm))
707 goto put;
708
709 dl = pwm_device_link_add(dev, pwm);
710 if (IS_ERR(dl)) {
711 /* of_xlate ended up calling pwm_request_from_chip() */
712 pwm_put(pwm);
713 pwm = ERR_CAST(dl);
714 goto put;
715 }
716
717 /*
718 * If a consumer name was not given, try to look it up from the
719 * "pwm-names" property if it exists. Otherwise use the name of
720 * the user device node.
721 */
722 if (!con_id) {
723 err = of_property_read_string_index(np, "pwm-names", index,
724 &con_id);
725 if (err < 0)
726 con_id = np->name;
727 }
728
729 pwm->label = con_id;
730
731put:
732 of_node_put(args.np);
733
734 return pwm;
735}
736
737/**
738 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
739 * @fwnode: firmware node to get the "pwms" property from
740 *
741 * Returns the PWM device parsed from the fwnode and index specified in the
742 * "pwms" property or a negative error-code on failure.
743 * Values parsed from the device tree are stored in the returned PWM device
744 * object.
745 *
746 * This is analogous to of_pwm_get() except con_id is not yet supported.
747 * ACPI entries must look like
748 * Package () {"pwms", Package ()
749 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
750 *
751 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
752 * error code on failure.
753 */
754static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
755{
756 struct pwm_device *pwm;
757 struct fwnode_reference_args args;
758 struct pwm_chip *chip;
759 int ret;
760
761 memset(&args, 0, sizeof(args));
762
763 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
764 if (ret < 0)
765 return ERR_PTR(ret);
766
767 if (args.nargs < 2)
768 return ERR_PTR(-EPROTO);
769
770 chip = fwnode_to_pwmchip(args.fwnode);
771 if (IS_ERR(chip))
772 return ERR_CAST(chip);
773
774 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
775 if (IS_ERR(pwm))
776 return pwm;
777
778 pwm->args.period = args.args[1];
779 pwm->args.polarity = PWM_POLARITY_NORMAL;
780
781 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
782 pwm->args.polarity = PWM_POLARITY_INVERSED;
783
784 return pwm;
785}
786
787/**
788 * pwm_add_table() - register PWM device consumers
789 * @table: array of consumers to register
790 * @num: number of consumers in table
791 */
792void pwm_add_table(struct pwm_lookup *table, size_t num)
793{
794 mutex_lock(&pwm_lookup_lock);
795
796 while (num--) {
797 list_add_tail(&table->list, &pwm_lookup_list);
798 table++;
799 }
800
801 mutex_unlock(&pwm_lookup_lock);
802}
803
804/**
805 * pwm_remove_table() - unregister PWM device consumers
806 * @table: array of consumers to unregister
807 * @num: number of consumers in table
808 */
809void pwm_remove_table(struct pwm_lookup *table, size_t num)
810{
811 mutex_lock(&pwm_lookup_lock);
812
813 while (num--) {
814 list_del(&table->list);
815 table++;
816 }
817
818 mutex_unlock(&pwm_lookup_lock);
819}
820
821/**
822 * pwm_get() - look up and request a PWM device
823 * @dev: device for PWM consumer
824 * @con_id: consumer name
825 *
826 * Lookup is first attempted using DT. If the device was not instantiated from
827 * a device tree, a PWM chip and a relative index is looked up via a table
828 * supplied by board setup code (see pwm_add_table()).
829 *
830 * Once a PWM chip has been found the specified PWM device will be requested
831 * and is ready to be used.
832 *
833 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
834 * error code on failure.
835 */
836struct pwm_device *pwm_get(struct device *dev, const char *con_id)
837{
838 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
839 const char *dev_id = dev ? dev_name(dev) : NULL;
840 struct pwm_device *pwm;
841 struct pwm_chip *chip;
842 struct device_link *dl;
843 unsigned int best = 0;
844 struct pwm_lookup *p, *chosen = NULL;
845 unsigned int match;
846 int err;
847
848 /* look up via DT first */
849 if (is_of_node(fwnode))
850 return of_pwm_get(dev, to_of_node(fwnode), con_id);
851
852 /* then lookup via ACPI */
853 if (is_acpi_node(fwnode)) {
854 pwm = acpi_pwm_get(fwnode);
855 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
856 return pwm;
857 }
858
859 /*
860 * We look up the provider in the static table typically provided by
861 * board setup code. We first try to lookup the consumer device by
862 * name. If the consumer device was passed in as NULL or if no match
863 * was found, we try to find the consumer by directly looking it up
864 * by name.
865 *
866 * If a match is found, the provider PWM chip is looked up by name
867 * and a PWM device is requested using the PWM device per-chip index.
868 *
869 * The lookup algorithm was shamelessly taken from the clock
870 * framework:
871 *
872 * We do slightly fuzzy matching here:
873 * An entry with a NULL ID is assumed to be a wildcard.
874 * If an entry has a device ID, it must match
875 * If an entry has a connection ID, it must match
876 * Then we take the most specific entry - with the following order
877 * of precedence: dev+con > dev only > con only.
878 */
879 mutex_lock(&pwm_lookup_lock);
880
881 list_for_each_entry(p, &pwm_lookup_list, list) {
882 match = 0;
883
884 if (p->dev_id) {
885 if (!dev_id || strcmp(p->dev_id, dev_id))
886 continue;
887
888 match += 2;
889 }
890
891 if (p->con_id) {
892 if (!con_id || strcmp(p->con_id, con_id))
893 continue;
894
895 match += 1;
896 }
897
898 if (match > best) {
899 chosen = p;
900
901 if (match != 3)
902 best = match;
903 else
904 break;
905 }
906 }
907
908 mutex_unlock(&pwm_lookup_lock);
909
910 if (!chosen)
911 return ERR_PTR(-ENODEV);
912
913 chip = pwmchip_find_by_name(chosen->provider);
914
915 /*
916 * If the lookup entry specifies a module, load the module and retry
917 * the PWM chip lookup. This can be used to work around driver load
918 * ordering issues if driver's can't be made to properly support the
919 * deferred probe mechanism.
920 */
921 if (!chip && chosen->module) {
922 err = request_module(chosen->module);
923 if (err == 0)
924 chip = pwmchip_find_by_name(chosen->provider);
925 }
926
927 if (!chip)
928 return ERR_PTR(-EPROBE_DEFER);
929
930 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
931 if (IS_ERR(pwm))
932 return pwm;
933
934 dl = pwm_device_link_add(dev, pwm);
935 if (IS_ERR(dl)) {
936 pwm_put(pwm);
937 return ERR_CAST(dl);
938 }
939
940 pwm->args.period = chosen->period;
941 pwm->args.polarity = chosen->polarity;
942
943 return pwm;
944}
945EXPORT_SYMBOL_GPL(pwm_get);
946
947/**
948 * pwm_put() - release a PWM device
949 * @pwm: PWM device
950 */
951void pwm_put(struct pwm_device *pwm)
952{
953 if (!pwm)
954 return;
955
956 mutex_lock(&pwm_lock);
957
958 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
959 pr_warn("PWM device already freed\n");
960 goto out;
961 }
962
963 if (pwm->chip->ops->free)
964 pwm->chip->ops->free(pwm->chip, pwm);
965
966 pwm->label = NULL;
967
968 module_put(pwm->chip->owner);
969out:
970 mutex_unlock(&pwm_lock);
971}
972EXPORT_SYMBOL_GPL(pwm_put);
973
974static void devm_pwm_release(void *pwm)
975{
976 pwm_put(pwm);
977}
978
979/**
980 * devm_pwm_get() - resource managed pwm_get()
981 * @dev: device for PWM consumer
982 * @con_id: consumer name
983 *
984 * This function performs like pwm_get() but the acquired PWM device will
985 * automatically be released on driver detach.
986 *
987 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
988 * error code on failure.
989 */
990struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
991{
992 struct pwm_device *pwm;
993 int ret;
994
995 pwm = pwm_get(dev, con_id);
996 if (IS_ERR(pwm))
997 return pwm;
998
999 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1000 if (ret)
1001 return ERR_PTR(ret);
1002
1003 return pwm;
1004}
1005EXPORT_SYMBOL_GPL(devm_pwm_get);
1006
1007/**
1008 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1009 * @dev: device for PWM consumer
1010 * @fwnode: firmware node to get the PWM from
1011 * @con_id: consumer name
1012 *
1013 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1014 * acpi_pwm_get() for a detailed description.
1015 *
1016 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1017 * error code on failure.
1018 */
1019struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1020 struct fwnode_handle *fwnode,
1021 const char *con_id)
1022{
1023 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1024 int ret;
1025
1026 if (is_of_node(fwnode))
1027 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1028 else if (is_acpi_node(fwnode))
1029 pwm = acpi_pwm_get(fwnode);
1030 if (IS_ERR(pwm))
1031 return pwm;
1032
1033 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1034 if (ret)
1035 return ERR_PTR(ret);
1036
1037 return pwm;
1038}
1039EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1040
1041#ifdef CONFIG_DEBUG_FS
1042static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1043{
1044 unsigned int i;
1045
1046 for (i = 0; i < chip->npwm; i++) {
1047 struct pwm_device *pwm = &chip->pwms[i];
1048 struct pwm_state state;
1049
1050 pwm_get_state(pwm, &state);
1051
1052 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1053
1054 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1055 seq_puts(s, " requested");
1056
1057 if (state.enabled)
1058 seq_puts(s, " enabled");
1059
1060 seq_printf(s, " period: %llu ns", state.period);
1061 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1062 seq_printf(s, " polarity: %s",
1063 state.polarity ? "inverse" : "normal");
1064
1065 if (state.usage_power)
1066 seq_puts(s, " usage_power");
1067
1068 seq_puts(s, "\n");
1069 }
1070}
1071
1072static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1073{
1074 unsigned long id = *pos;
1075 void *ret;
1076
1077 mutex_lock(&pwm_lock);
1078 s->private = "";
1079
1080 ret = idr_get_next_ul(&pwm_chips, &id);
1081 *pos = id;
1082 return ret;
1083}
1084
1085static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1086{
1087 unsigned long id = *pos + 1;
1088 void *ret;
1089
1090 s->private = "\n";
1091
1092 ret = idr_get_next_ul(&pwm_chips, &id);
1093 *pos = id;
1094 return ret;
1095}
1096
1097static void pwm_seq_stop(struct seq_file *s, void *v)
1098{
1099 mutex_unlock(&pwm_lock);
1100}
1101
1102static int pwm_seq_show(struct seq_file *s, void *v)
1103{
1104 struct pwm_chip *chip = v;
1105
1106 seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n",
1107 (char *)s->private, chip->id,
1108 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1109 dev_name(chip->dev), chip->npwm,
1110 (chip->npwm != 1) ? "s" : "");
1111
1112 pwm_dbg_show(chip, s);
1113
1114 return 0;
1115}
1116
1117static const struct seq_operations pwm_debugfs_sops = {
1118 .start = pwm_seq_start,
1119 .next = pwm_seq_next,
1120 .stop = pwm_seq_stop,
1121 .show = pwm_seq_show,
1122};
1123
1124DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1125
1126static int __init pwm_debugfs_init(void)
1127{
1128 debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1129
1130 return 0;
1131}
1132subsys_initcall(pwm_debugfs_init);
1133#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 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(unsigned int count)
41{
42 unsigned int start;
43
44 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, 0,
45 count, 0);
46
47 if (start + count > MAX_PWMS)
48 return -ENOSPC;
49
50 return start;
51}
52
53static void free_pwms(struct pwm_chip *chip)
54{
55 unsigned int i;
56
57 for (i = 0; i < chip->npwm; i++) {
58 struct pwm_device *pwm = &chip->pwms[i];
59
60 radix_tree_delete(&pwm_tree, pwm->pwm);
61 }
62
63 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
64
65 kfree(chip->pwms);
66 chip->pwms = NULL;
67}
68
69static struct pwm_chip *pwmchip_find_by_name(const char *name)
70{
71 struct pwm_chip *chip;
72
73 if (!name)
74 return NULL;
75
76 mutex_lock(&pwm_lock);
77
78 list_for_each_entry(chip, &pwm_chips, list) {
79 const char *chip_name = dev_name(chip->dev);
80
81 if (chip_name && strcmp(chip_name, name) == 0) {
82 mutex_unlock(&pwm_lock);
83 return chip;
84 }
85 }
86
87 mutex_unlock(&pwm_lock);
88
89 return NULL;
90}
91
92static int pwm_device_request(struct pwm_device *pwm, const char *label)
93{
94 int err;
95
96 if (test_bit(PWMF_REQUESTED, &pwm->flags))
97 return -EBUSY;
98
99 if (!try_module_get(pwm->chip->ops->owner))
100 return -ENODEV;
101
102 if (pwm->chip->ops->request) {
103 err = pwm->chip->ops->request(pwm->chip, pwm);
104 if (err) {
105 module_put(pwm->chip->ops->owner);
106 return err;
107 }
108 }
109
110 if (pwm->chip->ops->get_state) {
111 pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
112 trace_pwm_get(pwm, &pwm->state);
113
114 if (IS_ENABLED(CONFIG_PWM_DEBUG))
115 pwm->last = pwm->state;
116 }
117
118 set_bit(PWMF_REQUESTED, &pwm->flags);
119 pwm->label = label;
120
121 return 0;
122}
123
124struct pwm_device *
125of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
126{
127 struct pwm_device *pwm;
128
129 if (pc->of_pwm_n_cells < 2)
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 (pc->of_pwm_n_cells >= 3) {
147 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
148 pwm->args.polarity = PWM_POLARITY_INVERSED;
149 }
150
151 return pwm;
152}
153EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
154
155static void of_pwmchip_add(struct pwm_chip *chip)
156{
157 if (!chip->dev || !chip->dev->of_node)
158 return;
159
160 if (!chip->of_xlate) {
161 u32 pwm_cells;
162
163 if (of_property_read_u32(chip->dev->of_node, "#pwm-cells",
164 &pwm_cells))
165 pwm_cells = 2;
166
167 chip->of_xlate = of_pwm_xlate_with_flags;
168 chip->of_pwm_n_cells = pwm_cells;
169 }
170
171 of_node_get(chip->dev->of_node);
172}
173
174static void of_pwmchip_remove(struct pwm_chip *chip)
175{
176 if (chip->dev)
177 of_node_put(chip->dev->of_node);
178}
179
180/**
181 * pwm_set_chip_data() - set private chip data for a PWM
182 * @pwm: PWM device
183 * @data: pointer to chip-specific data
184 *
185 * Returns: 0 on success or a negative error code on failure.
186 */
187int pwm_set_chip_data(struct pwm_device *pwm, void *data)
188{
189 if (!pwm)
190 return -EINVAL;
191
192 pwm->chip_data = data;
193
194 return 0;
195}
196EXPORT_SYMBOL_GPL(pwm_set_chip_data);
197
198/**
199 * pwm_get_chip_data() - get private chip data for a PWM
200 * @pwm: PWM device
201 *
202 * Returns: A pointer to the chip-private data for the PWM device.
203 */
204void *pwm_get_chip_data(struct pwm_device *pwm)
205{
206 return pwm ? pwm->chip_data : NULL;
207}
208EXPORT_SYMBOL_GPL(pwm_get_chip_data);
209
210static bool pwm_ops_check(const struct pwm_chip *chip)
211{
212
213 const struct pwm_ops *ops = chip->ops;
214
215 /* driver supports legacy, non-atomic operation */
216 if (ops->config && ops->enable && ops->disable) {
217 if (IS_ENABLED(CONFIG_PWM_DEBUG))
218 dev_warn(chip->dev,
219 "Driver needs updating to atomic API\n");
220
221 return true;
222 }
223
224 if (!ops->apply)
225 return false;
226
227 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
228 dev_warn(chip->dev,
229 "Please implement the .get_state() callback\n");
230
231 return true;
232}
233
234/**
235 * pwmchip_add() - register a new PWM chip
236 * @chip: the PWM chip to add
237 *
238 * Register a new PWM chip.
239 *
240 * Returns: 0 on success or a negative error code on failure.
241 */
242int pwmchip_add(struct pwm_chip *chip)
243{
244 struct pwm_device *pwm;
245 unsigned int i;
246 int ret;
247
248 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
249 return -EINVAL;
250
251 if (!pwm_ops_check(chip))
252 return -EINVAL;
253
254 mutex_lock(&pwm_lock);
255
256 ret = alloc_pwms(chip->npwm);
257 if (ret < 0)
258 goto out;
259
260 chip->base = ret;
261
262 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
263 if (!chip->pwms) {
264 ret = -ENOMEM;
265 goto out;
266 }
267
268 for (i = 0; i < chip->npwm; i++) {
269 pwm = &chip->pwms[i];
270
271 pwm->chip = chip;
272 pwm->pwm = chip->base + i;
273 pwm->hwpwm = i;
274
275 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
276 }
277
278 bitmap_set(allocated_pwms, chip->base, chip->npwm);
279
280 INIT_LIST_HEAD(&chip->list);
281 list_add(&chip->list, &pwm_chips);
282
283 ret = 0;
284
285 if (IS_ENABLED(CONFIG_OF))
286 of_pwmchip_add(chip);
287
288out:
289 mutex_unlock(&pwm_lock);
290
291 if (!ret)
292 pwmchip_sysfs_export(chip);
293
294 return ret;
295}
296EXPORT_SYMBOL_GPL(pwmchip_add);
297
298/**
299 * pwmchip_remove() - remove a PWM chip
300 * @chip: the PWM chip to remove
301 *
302 * Removes a PWM chip. This function may return busy if the PWM chip provides
303 * a PWM device that is still requested.
304 *
305 * Returns: 0 on success or a negative error code on failure.
306 */
307int pwmchip_remove(struct pwm_chip *chip)
308{
309 pwmchip_sysfs_unexport(chip);
310
311 mutex_lock(&pwm_lock);
312
313 list_del_init(&chip->list);
314
315 if (IS_ENABLED(CONFIG_OF))
316 of_pwmchip_remove(chip);
317
318 free_pwms(chip);
319
320 mutex_unlock(&pwm_lock);
321
322 return 0;
323}
324EXPORT_SYMBOL_GPL(pwmchip_remove);
325
326static void devm_pwmchip_remove(void *data)
327{
328 struct pwm_chip *chip = data;
329
330 pwmchip_remove(chip);
331}
332
333int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip)
334{
335 int ret;
336
337 ret = pwmchip_add(chip);
338 if (ret)
339 return ret;
340
341 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
342}
343EXPORT_SYMBOL_GPL(devm_pwmchip_add);
344
345/**
346 * pwm_request() - request a PWM device
347 * @pwm: global PWM device index
348 * @label: PWM device label
349 *
350 * This function is deprecated, use pwm_get() instead.
351 *
352 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
353 * failure.
354 */
355struct pwm_device *pwm_request(int pwm, const char *label)
356{
357 struct pwm_device *dev;
358 int err;
359
360 if (pwm < 0 || pwm >= MAX_PWMS)
361 return ERR_PTR(-EINVAL);
362
363 mutex_lock(&pwm_lock);
364
365 dev = pwm_to_device(pwm);
366 if (!dev) {
367 dev = ERR_PTR(-EPROBE_DEFER);
368 goto out;
369 }
370
371 err = pwm_device_request(dev, label);
372 if (err < 0)
373 dev = ERR_PTR(err);
374
375out:
376 mutex_unlock(&pwm_lock);
377
378 return dev;
379}
380EXPORT_SYMBOL_GPL(pwm_request);
381
382/**
383 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
384 * @chip: PWM chip
385 * @index: per-chip index of the PWM to request
386 * @label: a literal description string of this PWM
387 *
388 * Returns: A pointer to the PWM device at the given index of the given PWM
389 * chip. A negative error code is returned if the index is not valid for the
390 * specified PWM chip or if the PWM device cannot be requested.
391 */
392struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
393 unsigned int index,
394 const char *label)
395{
396 struct pwm_device *pwm;
397 int err;
398
399 if (!chip || index >= chip->npwm)
400 return ERR_PTR(-EINVAL);
401
402 mutex_lock(&pwm_lock);
403 pwm = &chip->pwms[index];
404
405 err = pwm_device_request(pwm, label);
406 if (err < 0)
407 pwm = ERR_PTR(err);
408
409 mutex_unlock(&pwm_lock);
410 return pwm;
411}
412EXPORT_SYMBOL_GPL(pwm_request_from_chip);
413
414/**
415 * pwm_free() - free a PWM device
416 * @pwm: PWM device
417 *
418 * This function is deprecated, use pwm_put() instead.
419 */
420void pwm_free(struct pwm_device *pwm)
421{
422 pwm_put(pwm);
423}
424EXPORT_SYMBOL_GPL(pwm_free);
425
426static void pwm_apply_state_debug(struct pwm_device *pwm,
427 const struct pwm_state *state)
428{
429 struct pwm_state *last = &pwm->last;
430 struct pwm_chip *chip = pwm->chip;
431 struct pwm_state s1, s2;
432 int err;
433
434 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
435 return;
436
437 /* No reasonable diagnosis possible without .get_state() */
438 if (!chip->ops->get_state)
439 return;
440
441 /*
442 * *state was just applied. Read out the hardware state and do some
443 * checks.
444 */
445
446 chip->ops->get_state(chip, pwm, &s1);
447 trace_pwm_get(pwm, &s1);
448
449 /*
450 * The lowlevel driver either ignored .polarity (which is a bug) or as
451 * best effort inverted .polarity and fixed .duty_cycle respectively.
452 * Undo this inversion and fixup for further tests.
453 */
454 if (s1.enabled && s1.polarity != state->polarity) {
455 s2.polarity = state->polarity;
456 s2.duty_cycle = s1.period - s1.duty_cycle;
457 s2.period = s1.period;
458 s2.enabled = s1.enabled;
459 } else {
460 s2 = s1;
461 }
462
463 if (s2.polarity != state->polarity &&
464 state->duty_cycle < state->period)
465 dev_warn(chip->dev, ".apply ignored .polarity\n");
466
467 if (state->enabled &&
468 last->polarity == state->polarity &&
469 last->period > s2.period &&
470 last->period <= state->period)
471 dev_warn(chip->dev,
472 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
473 state->period, s2.period, last->period);
474
475 if (state->enabled && state->period < s2.period)
476 dev_warn(chip->dev,
477 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
478 state->period, s2.period);
479
480 if (state->enabled &&
481 last->polarity == state->polarity &&
482 last->period == s2.period &&
483 last->duty_cycle > s2.duty_cycle &&
484 last->duty_cycle <= state->duty_cycle)
485 dev_warn(chip->dev,
486 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
487 state->duty_cycle, state->period,
488 s2.duty_cycle, s2.period,
489 last->duty_cycle, last->period);
490
491 if (state->enabled && state->duty_cycle < s2.duty_cycle)
492 dev_warn(chip->dev,
493 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
494 state->duty_cycle, state->period,
495 s2.duty_cycle, s2.period);
496
497 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
498 dev_warn(chip->dev,
499 "requested disabled, but yielded enabled with duty > 0\n");
500
501 /* reapply the state that the driver reported being configured. */
502 err = chip->ops->apply(chip, pwm, &s1);
503 if (err) {
504 *last = s1;
505 dev_err(chip->dev, "failed to reapply current setting\n");
506 return;
507 }
508
509 trace_pwm_apply(pwm, &s1);
510
511 chip->ops->get_state(chip, pwm, last);
512 trace_pwm_get(pwm, last);
513
514 /* reapplication of the current state should give an exact match */
515 if (s1.enabled != last->enabled ||
516 s1.polarity != last->polarity ||
517 (s1.enabled && s1.period != last->period) ||
518 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
519 dev_err(chip->dev,
520 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
521 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
522 last->enabled, last->polarity, last->duty_cycle,
523 last->period);
524 }
525}
526
527/**
528 * pwm_apply_state() - atomically apply a new state to a PWM device
529 * @pwm: PWM device
530 * @state: new state to apply
531 */
532int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
533{
534 struct pwm_chip *chip;
535 int err;
536
537 if (!pwm || !state || !state->period ||
538 state->duty_cycle > state->period)
539 return -EINVAL;
540
541 chip = pwm->chip;
542
543 if (state->period == pwm->state.period &&
544 state->duty_cycle == pwm->state.duty_cycle &&
545 state->polarity == pwm->state.polarity &&
546 state->enabled == pwm->state.enabled &&
547 state->usage_power == pwm->state.usage_power)
548 return 0;
549
550 if (chip->ops->apply) {
551 err = chip->ops->apply(chip, pwm, state);
552 if (err)
553 return err;
554
555 trace_pwm_apply(pwm, state);
556
557 pwm->state = *state;
558
559 /*
560 * only do this after pwm->state was applied as some
561 * implementations of .get_state depend on this
562 */
563 pwm_apply_state_debug(pwm, state);
564 } else {
565 /*
566 * FIXME: restore the initial state in case of error.
567 */
568 if (state->polarity != pwm->state.polarity) {
569 if (!chip->ops->set_polarity)
570 return -EINVAL;
571
572 /*
573 * Changing the polarity of a running PWM is
574 * only allowed when the PWM driver implements
575 * ->apply().
576 */
577 if (pwm->state.enabled) {
578 chip->ops->disable(chip, pwm);
579 pwm->state.enabled = false;
580 }
581
582 err = chip->ops->set_polarity(chip, pwm,
583 state->polarity);
584 if (err)
585 return err;
586
587 pwm->state.polarity = state->polarity;
588 }
589
590 if (state->period != pwm->state.period ||
591 state->duty_cycle != pwm->state.duty_cycle) {
592 err = chip->ops->config(pwm->chip, pwm,
593 state->duty_cycle,
594 state->period);
595 if (err)
596 return err;
597
598 pwm->state.duty_cycle = state->duty_cycle;
599 pwm->state.period = state->period;
600 }
601
602 if (state->enabled != pwm->state.enabled) {
603 if (state->enabled) {
604 err = chip->ops->enable(chip, pwm);
605 if (err)
606 return err;
607 } else {
608 chip->ops->disable(chip, pwm);
609 }
610
611 pwm->state.enabled = state->enabled;
612 }
613 }
614
615 return 0;
616}
617EXPORT_SYMBOL_GPL(pwm_apply_state);
618
619/**
620 * pwm_capture() - capture and report a PWM signal
621 * @pwm: PWM device
622 * @result: structure to fill with capture result
623 * @timeout: time to wait, in milliseconds, before giving up on capture
624 *
625 * Returns: 0 on success or a negative error code on failure.
626 */
627int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
628 unsigned long timeout)
629{
630 int err;
631
632 if (!pwm || !pwm->chip->ops)
633 return -EINVAL;
634
635 if (!pwm->chip->ops->capture)
636 return -ENOSYS;
637
638 mutex_lock(&pwm_lock);
639 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
640 mutex_unlock(&pwm_lock);
641
642 return err;
643}
644EXPORT_SYMBOL_GPL(pwm_capture);
645
646/**
647 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
648 * @pwm: PWM device
649 *
650 * This function will adjust the PWM config to the PWM arguments provided
651 * by the DT or PWM lookup table. This is particularly useful to adapt
652 * the bootloader config to the Linux one.
653 */
654int pwm_adjust_config(struct pwm_device *pwm)
655{
656 struct pwm_state state;
657 struct pwm_args pargs;
658
659 pwm_get_args(pwm, &pargs);
660 pwm_get_state(pwm, &state);
661
662 /*
663 * If the current period is zero it means that either the PWM driver
664 * does not support initial state retrieval or the PWM has not yet
665 * been configured.
666 *
667 * In either case, we setup the new period and polarity, and assign a
668 * duty cycle of 0.
669 */
670 if (!state.period) {
671 state.duty_cycle = 0;
672 state.period = pargs.period;
673 state.polarity = pargs.polarity;
674
675 return pwm_apply_state(pwm, &state);
676 }
677
678 /*
679 * Adjust the PWM duty cycle/period based on the period value provided
680 * in PWM args.
681 */
682 if (pargs.period != state.period) {
683 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
684
685 do_div(dutycycle, state.period);
686 state.duty_cycle = dutycycle;
687 state.period = pargs.period;
688 }
689
690 /*
691 * If the polarity changed, we should also change the duty cycle.
692 */
693 if (pargs.polarity != state.polarity) {
694 state.polarity = pargs.polarity;
695 state.duty_cycle = state.period - state.duty_cycle;
696 }
697
698 return pwm_apply_state(pwm, &state);
699}
700EXPORT_SYMBOL_GPL(pwm_adjust_config);
701
702static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
703{
704 struct pwm_chip *chip;
705
706 mutex_lock(&pwm_lock);
707
708 list_for_each_entry(chip, &pwm_chips, list)
709 if (chip->dev && dev_fwnode(chip->dev) == fwnode) {
710 mutex_unlock(&pwm_lock);
711 return chip;
712 }
713
714 mutex_unlock(&pwm_lock);
715
716 return ERR_PTR(-EPROBE_DEFER);
717}
718
719static struct device_link *pwm_device_link_add(struct device *dev,
720 struct pwm_device *pwm)
721{
722 struct device_link *dl;
723
724 if (!dev) {
725 /*
726 * No device for the PWM consumer has been provided. It may
727 * impact the PM sequence ordering: the PWM supplier may get
728 * suspended before the consumer.
729 */
730 dev_warn(pwm->chip->dev,
731 "No consumer device specified to create a link to\n");
732 return NULL;
733 }
734
735 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
736 if (!dl) {
737 dev_err(dev, "failed to create device link to %s\n",
738 dev_name(pwm->chip->dev));
739 return ERR_PTR(-EINVAL);
740 }
741
742 return dl;
743}
744
745/**
746 * of_pwm_get() - request a PWM via the PWM framework
747 * @dev: device for PWM consumer
748 * @np: device node to get the PWM from
749 * @con_id: consumer name
750 *
751 * Returns the PWM device parsed from the phandle and index specified in the
752 * "pwms" property of a device tree node or a negative error-code on failure.
753 * Values parsed from the device tree are stored in the returned PWM device
754 * object.
755 *
756 * If con_id is NULL, the first PWM device listed in the "pwms" property will
757 * be requested. Otherwise the "pwm-names" property is used to do a reverse
758 * lookup of the PWM index. This also means that the "pwm-names" property
759 * becomes mandatory for devices that look up the PWM device via the con_id
760 * parameter.
761 *
762 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
763 * error code on failure.
764 */
765struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
766 const char *con_id)
767{
768 struct pwm_device *pwm = NULL;
769 struct of_phandle_args args;
770 struct device_link *dl;
771 struct pwm_chip *pc;
772 int index = 0;
773 int err;
774
775 if (con_id) {
776 index = of_property_match_string(np, "pwm-names", con_id);
777 if (index < 0)
778 return ERR_PTR(index);
779 }
780
781 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
782 &args);
783 if (err) {
784 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
785 return ERR_PTR(err);
786 }
787
788 pc = fwnode_to_pwmchip(of_fwnode_handle(args.np));
789 if (IS_ERR(pc)) {
790 if (PTR_ERR(pc) != -EPROBE_DEFER)
791 pr_err("%s(): PWM chip not found\n", __func__);
792
793 pwm = ERR_CAST(pc);
794 goto put;
795 }
796
797 pwm = pc->of_xlate(pc, &args);
798 if (IS_ERR(pwm))
799 goto put;
800
801 dl = pwm_device_link_add(dev, pwm);
802 if (IS_ERR(dl)) {
803 /* of_xlate ended up calling pwm_request_from_chip() */
804 pwm_free(pwm);
805 pwm = ERR_CAST(dl);
806 goto put;
807 }
808
809 /*
810 * If a consumer name was not given, try to look it up from the
811 * "pwm-names" property if it exists. Otherwise use the name of
812 * the user device node.
813 */
814 if (!con_id) {
815 err = of_property_read_string_index(np, "pwm-names", index,
816 &con_id);
817 if (err < 0)
818 con_id = np->name;
819 }
820
821 pwm->label = con_id;
822
823put:
824 of_node_put(args.np);
825
826 return pwm;
827}
828EXPORT_SYMBOL_GPL(of_pwm_get);
829
830/**
831 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
832 * @fwnode: firmware node to get the "pwms" property from
833 *
834 * Returns the PWM device parsed from the fwnode and index specified in the
835 * "pwms" property or a negative error-code on failure.
836 * Values parsed from the device tree are stored in the returned PWM device
837 * object.
838 *
839 * This is analogous to of_pwm_get() except con_id is not yet supported.
840 * ACPI entries must look like
841 * Package () {"pwms", Package ()
842 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
843 *
844 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
845 * error code on failure.
846 */
847static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
848{
849 struct pwm_device *pwm;
850 struct fwnode_reference_args args;
851 struct pwm_chip *chip;
852 int ret;
853
854 memset(&args, 0, sizeof(args));
855
856 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
857 if (ret < 0)
858 return ERR_PTR(ret);
859
860 if (args.nargs < 2)
861 return ERR_PTR(-EPROTO);
862
863 chip = fwnode_to_pwmchip(args.fwnode);
864 if (IS_ERR(chip))
865 return ERR_CAST(chip);
866
867 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
868 if (IS_ERR(pwm))
869 return pwm;
870
871 pwm->args.period = args.args[1];
872 pwm->args.polarity = PWM_POLARITY_NORMAL;
873
874 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
875 pwm->args.polarity = PWM_POLARITY_INVERSED;
876
877 return pwm;
878}
879
880/**
881 * pwm_add_table() - register PWM device consumers
882 * @table: array of consumers to register
883 * @num: number of consumers in table
884 */
885void pwm_add_table(struct pwm_lookup *table, size_t num)
886{
887 mutex_lock(&pwm_lookup_lock);
888
889 while (num--) {
890 list_add_tail(&table->list, &pwm_lookup_list);
891 table++;
892 }
893
894 mutex_unlock(&pwm_lookup_lock);
895}
896
897/**
898 * pwm_remove_table() - unregister PWM device consumers
899 * @table: array of consumers to unregister
900 * @num: number of consumers in table
901 */
902void pwm_remove_table(struct pwm_lookup *table, size_t num)
903{
904 mutex_lock(&pwm_lookup_lock);
905
906 while (num--) {
907 list_del(&table->list);
908 table++;
909 }
910
911 mutex_unlock(&pwm_lookup_lock);
912}
913
914/**
915 * pwm_get() - look up and request a PWM device
916 * @dev: device for PWM consumer
917 * @con_id: consumer name
918 *
919 * Lookup is first attempted using DT. If the device was not instantiated from
920 * a device tree, a PWM chip and a relative index is looked up via a table
921 * supplied by board setup code (see pwm_add_table()).
922 *
923 * Once a PWM chip has been found the specified PWM device will be requested
924 * and is ready to be used.
925 *
926 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
927 * error code on failure.
928 */
929struct pwm_device *pwm_get(struct device *dev, const char *con_id)
930{
931 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
932 const char *dev_id = dev ? dev_name(dev) : NULL;
933 struct pwm_device *pwm;
934 struct pwm_chip *chip;
935 struct device_link *dl;
936 unsigned int best = 0;
937 struct pwm_lookup *p, *chosen = NULL;
938 unsigned int match;
939 int err;
940
941 /* look up via DT first */
942 if (is_of_node(fwnode))
943 return of_pwm_get(dev, to_of_node(fwnode), con_id);
944
945 /* then lookup via ACPI */
946 if (is_acpi_node(fwnode)) {
947 pwm = acpi_pwm_get(fwnode);
948 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
949 return pwm;
950 }
951
952 /*
953 * We look up the provider in the static table typically provided by
954 * board setup code. We first try to lookup the consumer device by
955 * name. If the consumer device was passed in as NULL or if no match
956 * was found, we try to find the consumer by directly looking it up
957 * by name.
958 *
959 * If a match is found, the provider PWM chip is looked up by name
960 * and a PWM device is requested using the PWM device per-chip index.
961 *
962 * The lookup algorithm was shamelessly taken from the clock
963 * framework:
964 *
965 * We do slightly fuzzy matching here:
966 * An entry with a NULL ID is assumed to be a wildcard.
967 * If an entry has a device ID, it must match
968 * If an entry has a connection ID, it must match
969 * Then we take the most specific entry - with the following order
970 * of precedence: dev+con > dev only > con only.
971 */
972 mutex_lock(&pwm_lookup_lock);
973
974 list_for_each_entry(p, &pwm_lookup_list, list) {
975 match = 0;
976
977 if (p->dev_id) {
978 if (!dev_id || strcmp(p->dev_id, dev_id))
979 continue;
980
981 match += 2;
982 }
983
984 if (p->con_id) {
985 if (!con_id || strcmp(p->con_id, con_id))
986 continue;
987
988 match += 1;
989 }
990
991 if (match > best) {
992 chosen = p;
993
994 if (match != 3)
995 best = match;
996 else
997 break;
998 }
999 }
1000
1001 mutex_unlock(&pwm_lookup_lock);
1002
1003 if (!chosen)
1004 return ERR_PTR(-ENODEV);
1005
1006 chip = pwmchip_find_by_name(chosen->provider);
1007
1008 /*
1009 * If the lookup entry specifies a module, load the module and retry
1010 * the PWM chip lookup. This can be used to work around driver load
1011 * ordering issues if driver's can't be made to properly support the
1012 * deferred probe mechanism.
1013 */
1014 if (!chip && chosen->module) {
1015 err = request_module(chosen->module);
1016 if (err == 0)
1017 chip = pwmchip_find_by_name(chosen->provider);
1018 }
1019
1020 if (!chip)
1021 return ERR_PTR(-EPROBE_DEFER);
1022
1023 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1024 if (IS_ERR(pwm))
1025 return pwm;
1026
1027 dl = pwm_device_link_add(dev, pwm);
1028 if (IS_ERR(dl)) {
1029 pwm_free(pwm);
1030 return ERR_CAST(dl);
1031 }
1032
1033 pwm->args.period = chosen->period;
1034 pwm->args.polarity = chosen->polarity;
1035
1036 return pwm;
1037}
1038EXPORT_SYMBOL_GPL(pwm_get);
1039
1040/**
1041 * pwm_put() - release a PWM device
1042 * @pwm: PWM device
1043 */
1044void pwm_put(struct pwm_device *pwm)
1045{
1046 if (!pwm)
1047 return;
1048
1049 mutex_lock(&pwm_lock);
1050
1051 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1052 pr_warn("PWM device already freed\n");
1053 goto out;
1054 }
1055
1056 if (pwm->chip->ops->free)
1057 pwm->chip->ops->free(pwm->chip, pwm);
1058
1059 pwm_set_chip_data(pwm, NULL);
1060 pwm->label = NULL;
1061
1062 module_put(pwm->chip->ops->owner);
1063out:
1064 mutex_unlock(&pwm_lock);
1065}
1066EXPORT_SYMBOL_GPL(pwm_put);
1067
1068static void devm_pwm_release(void *pwm)
1069{
1070 pwm_put(pwm);
1071}
1072
1073/**
1074 * devm_pwm_get() - resource managed pwm_get()
1075 * @dev: device for PWM consumer
1076 * @con_id: consumer name
1077 *
1078 * This function performs like pwm_get() but the acquired PWM device will
1079 * automatically be released on driver detach.
1080 *
1081 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1082 * error code on failure.
1083 */
1084struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1085{
1086 struct pwm_device *pwm;
1087 int ret;
1088
1089 pwm = pwm_get(dev, con_id);
1090 if (IS_ERR(pwm))
1091 return pwm;
1092
1093 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1094 if (ret)
1095 return ERR_PTR(ret);
1096
1097 return pwm;
1098}
1099EXPORT_SYMBOL_GPL(devm_pwm_get);
1100
1101/**
1102 * devm_of_pwm_get() - resource managed of_pwm_get()
1103 * @dev: device for PWM consumer
1104 * @np: device node to get the PWM from
1105 * @con_id: consumer name
1106 *
1107 * This function performs like of_pwm_get() but the acquired PWM device will
1108 * automatically be released on driver detach.
1109 *
1110 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1111 * error code on failure.
1112 */
1113struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
1114 const char *con_id)
1115{
1116 struct pwm_device *pwm;
1117 int ret;
1118
1119 pwm = of_pwm_get(dev, np, con_id);
1120 if (IS_ERR(pwm))
1121 return pwm;
1122
1123 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1124 if (ret)
1125 return ERR_PTR(ret);
1126
1127 return pwm;
1128}
1129EXPORT_SYMBOL_GPL(devm_of_pwm_get);
1130
1131/**
1132 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1133 * @dev: device for PWM consumer
1134 * @fwnode: firmware node to get the PWM from
1135 * @con_id: consumer name
1136 *
1137 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1138 * acpi_pwm_get() for a detailed description.
1139 *
1140 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1141 * error code on failure.
1142 */
1143struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1144 struct fwnode_handle *fwnode,
1145 const char *con_id)
1146{
1147 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1148 int ret;
1149
1150 if (is_of_node(fwnode))
1151 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1152 else if (is_acpi_node(fwnode))
1153 pwm = acpi_pwm_get(fwnode);
1154 if (IS_ERR(pwm))
1155 return pwm;
1156
1157 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1158 if (ret)
1159 return ERR_PTR(ret);
1160
1161 return pwm;
1162}
1163EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1164
1165#ifdef CONFIG_DEBUG_FS
1166static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1167{
1168 unsigned int i;
1169
1170 for (i = 0; i < chip->npwm; i++) {
1171 struct pwm_device *pwm = &chip->pwms[i];
1172 struct pwm_state state;
1173
1174 pwm_get_state(pwm, &state);
1175
1176 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1177
1178 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1179 seq_puts(s, " requested");
1180
1181 if (state.enabled)
1182 seq_puts(s, " enabled");
1183
1184 seq_printf(s, " period: %llu ns", state.period);
1185 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1186 seq_printf(s, " polarity: %s",
1187 state.polarity ? "inverse" : "normal");
1188
1189 if (state.usage_power)
1190 seq_puts(s, " usage_power");
1191
1192 seq_puts(s, "\n");
1193 }
1194}
1195
1196static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1197{
1198 mutex_lock(&pwm_lock);
1199 s->private = "";
1200
1201 return seq_list_start(&pwm_chips, *pos);
1202}
1203
1204static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1205{
1206 s->private = "\n";
1207
1208 return seq_list_next(v, &pwm_chips, pos);
1209}
1210
1211static void pwm_seq_stop(struct seq_file *s, void *v)
1212{
1213 mutex_unlock(&pwm_lock);
1214}
1215
1216static int pwm_seq_show(struct seq_file *s, void *v)
1217{
1218 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1219
1220 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1221 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1222 dev_name(chip->dev), chip->npwm,
1223 (chip->npwm != 1) ? "s" : "");
1224
1225 pwm_dbg_show(chip, s);
1226
1227 return 0;
1228}
1229
1230static const struct seq_operations pwm_debugfs_sops = {
1231 .start = pwm_seq_start,
1232 .next = pwm_seq_next,
1233 .stop = pwm_seq_stop,
1234 .show = pwm_seq_show,
1235};
1236
1237DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1238
1239static int __init pwm_debugfs_init(void)
1240{
1241 debugfs_create_file("pwm", S_IFREG | 0444, NULL, NULL,
1242 &pwm_debugfs_fops);
1243
1244 return 0;
1245}
1246subsys_initcall(pwm_debugfs_init);
1247#endif /* CONFIG_DEBUG_FS */