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