xref: /linux/drivers/pwm/core.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
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 #define DEFAULT_SYMBOL_NAMESPACE PWM
10 
11 #include <linux/acpi.h>
12 #include <linux/module.h>
13 #include <linux/idr.h>
14 #include <linux/of.h>
15 #include <linux/pwm.h>
16 #include <linux/list.h>
17 #include <linux/mutex.h>
18 #include <linux/err.h>
19 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/debugfs.h>
22 #include <linux/seq_file.h>
23 
24 #include <dt-bindings/pwm/pwm.h>
25 
26 #define CREATE_TRACE_POINTS
27 #include <trace/events/pwm.h>
28 
29 /* protects access to pwm_chips */
30 static DEFINE_MUTEX(pwm_lock);
31 
32 static DEFINE_IDR(pwm_chips);
33 
34 static void pwm_apply_debug(struct pwm_device *pwm,
35 			    const struct pwm_state *state)
36 {
37 	struct pwm_state *last = &pwm->last;
38 	struct pwm_chip *chip = pwm->chip;
39 	struct pwm_state s1 = { 0 }, s2 = { 0 };
40 	int err;
41 
42 	if (!IS_ENABLED(CONFIG_PWM_DEBUG))
43 		return;
44 
45 	/* No reasonable diagnosis possible without .get_state() */
46 	if (!chip->ops->get_state)
47 		return;
48 
49 	/*
50 	 * *state was just applied. Read out the hardware state and do some
51 	 * checks.
52 	 */
53 
54 	err = chip->ops->get_state(chip, pwm, &s1);
55 	trace_pwm_get(pwm, &s1, err);
56 	if (err)
57 		/* If that failed there isn't much to debug */
58 		return;
59 
60 	/*
61 	 * The lowlevel driver either ignored .polarity (which is a bug) or as
62 	 * best effort inverted .polarity and fixed .duty_cycle respectively.
63 	 * Undo this inversion and fixup for further tests.
64 	 */
65 	if (s1.enabled && s1.polarity != state->polarity) {
66 		s2.polarity = state->polarity;
67 		s2.duty_cycle = s1.period - s1.duty_cycle;
68 		s2.period = s1.period;
69 		s2.enabled = s1.enabled;
70 	} else {
71 		s2 = s1;
72 	}
73 
74 	if (s2.polarity != state->polarity &&
75 	    state->duty_cycle < state->period)
76 		dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n");
77 
78 	if (state->enabled &&
79 	    last->polarity == state->polarity &&
80 	    last->period > s2.period &&
81 	    last->period <= state->period)
82 		dev_warn(pwmchip_parent(chip),
83 			 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
84 			 state->period, s2.period, last->period);
85 
86 	if (state->enabled && state->period < s2.period)
87 		dev_warn(pwmchip_parent(chip),
88 			 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
89 			 state->period, s2.period);
90 
91 	if (state->enabled &&
92 	    last->polarity == state->polarity &&
93 	    last->period == s2.period &&
94 	    last->duty_cycle > s2.duty_cycle &&
95 	    last->duty_cycle <= state->duty_cycle)
96 		dev_warn(pwmchip_parent(chip),
97 			 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
98 			 state->duty_cycle, state->period,
99 			 s2.duty_cycle, s2.period,
100 			 last->duty_cycle, last->period);
101 
102 	if (state->enabled && state->duty_cycle < s2.duty_cycle)
103 		dev_warn(pwmchip_parent(chip),
104 			 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
105 			 state->duty_cycle, state->period,
106 			 s2.duty_cycle, s2.period);
107 
108 	if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
109 		dev_warn(pwmchip_parent(chip),
110 			 "requested disabled, but yielded enabled with duty > 0\n");
111 
112 	/* reapply the state that the driver reported being configured. */
113 	err = chip->ops->apply(chip, pwm, &s1);
114 	trace_pwm_apply(pwm, &s1, err);
115 	if (err) {
116 		*last = s1;
117 		dev_err(pwmchip_parent(chip), "failed to reapply current setting\n");
118 		return;
119 	}
120 
121 	*last = (struct pwm_state){ 0 };
122 	err = chip->ops->get_state(chip, pwm, last);
123 	trace_pwm_get(pwm, last, err);
124 	if (err)
125 		return;
126 
127 	/* reapplication of the current state should give an exact match */
128 	if (s1.enabled != last->enabled ||
129 	    s1.polarity != last->polarity ||
130 	    (s1.enabled && s1.period != last->period) ||
131 	    (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
132 		dev_err(pwmchip_parent(chip),
133 			".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
134 			s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
135 			last->enabled, last->polarity, last->duty_cycle,
136 			last->period);
137 	}
138 }
139 
140 static bool pwm_state_valid(const struct pwm_state *state)
141 {
142 	/*
143 	 * For a disabled state all other state description is irrelevant and
144 	 * and supposed to be ignored. So also ignore any strange values and
145 	 * consider the state ok.
146 	 */
147 	if (state->enabled)
148 		return true;
149 
150 	if (!state->period)
151 		return false;
152 
153 	if (state->duty_cycle > state->period)
154 		return false;
155 
156 	return true;
157 }
158 
159 /**
160  * __pwm_apply() - atomically apply a new state to a PWM device
161  * @pwm: PWM device
162  * @state: new state to apply
163  */
164 static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
165 {
166 	struct pwm_chip *chip;
167 	int err;
168 
169 	if (!pwm || !state)
170 		return -EINVAL;
171 
172 	if (!pwm_state_valid(state)) {
173 		/*
174 		 * Allow to transition from one invalid state to another.
175 		 * This ensures that you can e.g. change the polarity while
176 		 * the period is zero. (This happens on stm32 when the hardware
177 		 * is in its poweron default state.) This greatly simplifies
178 		 * working with the sysfs API where you can only change one
179 		 * parameter at a time.
180 		 */
181 		if (!pwm_state_valid(&pwm->state)) {
182 			pwm->state = *state;
183 			return 0;
184 		}
185 
186 		return -EINVAL;
187 	}
188 
189 	chip = pwm->chip;
190 
191 	if (state->period == pwm->state.period &&
192 	    state->duty_cycle == pwm->state.duty_cycle &&
193 	    state->polarity == pwm->state.polarity &&
194 	    state->enabled == pwm->state.enabled &&
195 	    state->usage_power == pwm->state.usage_power)
196 		return 0;
197 
198 	err = chip->ops->apply(chip, pwm, state);
199 	trace_pwm_apply(pwm, state, err);
200 	if (err)
201 		return err;
202 
203 	pwm->state = *state;
204 
205 	/*
206 	 * only do this after pwm->state was applied as some
207 	 * implementations of .get_state depend on this
208 	 */
209 	pwm_apply_debug(pwm, state);
210 
211 	return 0;
212 }
213 
214 /**
215  * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
216  * Cannot be used in atomic context.
217  * @pwm: PWM device
218  * @state: new state to apply
219  */
220 int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
221 {
222 	int err;
223 
224 	/*
225 	 * Some lowlevel driver's implementations of .apply() make use of
226 	 * mutexes, also with some drivers only returning when the new
227 	 * configuration is active calling pwm_apply_might_sleep() from atomic context
228 	 * is a bad idea. So make it explicit that calling this function might
229 	 * sleep.
230 	 */
231 	might_sleep();
232 
233 	if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
234 		/*
235 		 * Catch any drivers that have been marked as atomic but
236 		 * that will sleep anyway.
237 		 */
238 		non_block_start();
239 		err = __pwm_apply(pwm, state);
240 		non_block_end();
241 	} else {
242 		err = __pwm_apply(pwm, state);
243 	}
244 
245 	return err;
246 }
247 EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);
248 
249 /**
250  * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
251  * Not all PWM devices support this function, check with pwm_might_sleep().
252  * @pwm: PWM device
253  * @state: new state to apply
254  */
255 int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
256 {
257 	WARN_ONCE(!pwm->chip->atomic,
258 		  "sleeping PWM driver used in atomic context\n");
259 
260 	return __pwm_apply(pwm, state);
261 }
262 EXPORT_SYMBOL_GPL(pwm_apply_atomic);
263 
264 /**
265  * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
266  * @pwm: PWM device
267  *
268  * This function will adjust the PWM config to the PWM arguments provided
269  * by the DT or PWM lookup table. This is particularly useful to adapt
270  * the bootloader config to the Linux one.
271  */
272 int pwm_adjust_config(struct pwm_device *pwm)
273 {
274 	struct pwm_state state;
275 	struct pwm_args pargs;
276 
277 	pwm_get_args(pwm, &pargs);
278 	pwm_get_state(pwm, &state);
279 
280 	/*
281 	 * If the current period is zero it means that either the PWM driver
282 	 * does not support initial state retrieval or the PWM has not yet
283 	 * been configured.
284 	 *
285 	 * In either case, we setup the new period and polarity, and assign a
286 	 * duty cycle of 0.
287 	 */
288 	if (!state.period) {
289 		state.duty_cycle = 0;
290 		state.period = pargs.period;
291 		state.polarity = pargs.polarity;
292 
293 		return pwm_apply_might_sleep(pwm, &state);
294 	}
295 
296 	/*
297 	 * Adjust the PWM duty cycle/period based on the period value provided
298 	 * in PWM args.
299 	 */
300 	if (pargs.period != state.period) {
301 		u64 dutycycle = (u64)state.duty_cycle * pargs.period;
302 
303 		do_div(dutycycle, state.period);
304 		state.duty_cycle = dutycycle;
305 		state.period = pargs.period;
306 	}
307 
308 	/*
309 	 * If the polarity changed, we should also change the duty cycle.
310 	 */
311 	if (pargs.polarity != state.polarity) {
312 		state.polarity = pargs.polarity;
313 		state.duty_cycle = state.period - state.duty_cycle;
314 	}
315 
316 	return pwm_apply_might_sleep(pwm, &state);
317 }
318 EXPORT_SYMBOL_GPL(pwm_adjust_config);
319 
320 /**
321  * pwm_capture() - capture and report a PWM signal
322  * @pwm: PWM device
323  * @result: structure to fill with capture result
324  * @timeout: time to wait, in milliseconds, before giving up on capture
325  *
326  * Returns: 0 on success or a negative error code on failure.
327  */
328 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
329 		unsigned long timeout)
330 {
331 	if (!pwm || !pwm->chip->ops)
332 		return -EINVAL;
333 
334 	if (!pwm->chip->ops->capture)
335 		return -ENOSYS;
336 
337 	guard(mutex)(&pwm_lock);
338 
339 	return pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
340 }
341 EXPORT_SYMBOL_GPL(pwm_capture);
342 
343 static struct pwm_chip *pwmchip_find_by_name(const char *name)
344 {
345 	struct pwm_chip *chip;
346 	unsigned long id, tmp;
347 
348 	if (!name)
349 		return NULL;
350 
351 	guard(mutex)(&pwm_lock);
352 
353 	idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
354 		const char *chip_name = dev_name(pwmchip_parent(chip));
355 
356 		if (chip_name && strcmp(chip_name, name) == 0)
357 			return chip;
358 	}
359 
360 	return NULL;
361 }
362 
363 static int pwm_device_request(struct pwm_device *pwm, const char *label)
364 {
365 	int err;
366 	struct pwm_chip *chip = pwm->chip;
367 	const struct pwm_ops *ops = chip->ops;
368 
369 	if (test_bit(PWMF_REQUESTED, &pwm->flags))
370 		return -EBUSY;
371 
372 	if (!try_module_get(chip->owner))
373 		return -ENODEV;
374 
375 	if (!get_device(&chip->dev)) {
376 		err = -ENODEV;
377 		goto err_get_device;
378 	}
379 
380 	if (ops->request) {
381 		err = ops->request(chip, pwm);
382 		if (err) {
383 			put_device(&chip->dev);
384 err_get_device:
385 			module_put(chip->owner);
386 			return err;
387 		}
388 	}
389 
390 	if (ops->get_state) {
391 		/*
392 		 * Zero-initialize state because most drivers are unaware of
393 		 * .usage_power. The other members of state are supposed to be
394 		 * set by lowlevel drivers. We still initialize the whole
395 		 * structure for simplicity even though this might paper over
396 		 * faulty implementations of .get_state().
397 		 */
398 		struct pwm_state state = { 0, };
399 
400 		err = ops->get_state(chip, pwm, &state);
401 		trace_pwm_get(pwm, &state, err);
402 
403 		if (!err)
404 			pwm->state = state;
405 
406 		if (IS_ENABLED(CONFIG_PWM_DEBUG))
407 			pwm->last = pwm->state;
408 	}
409 
410 	set_bit(PWMF_REQUESTED, &pwm->flags);
411 	pwm->label = label;
412 
413 	return 0;
414 }
415 
416 /**
417  * pwm_request_from_chip() - request a PWM device relative to a PWM chip
418  * @chip: PWM chip
419  * @index: per-chip index of the PWM to request
420  * @label: a literal description string of this PWM
421  *
422  * Returns: A pointer to the PWM device at the given index of the given PWM
423  * chip. A negative error code is returned if the index is not valid for the
424  * specified PWM chip or if the PWM device cannot be requested.
425  */
426 static struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
427 						unsigned int index,
428 						const char *label)
429 {
430 	struct pwm_device *pwm;
431 	int err;
432 
433 	if (!chip || index >= chip->npwm)
434 		return ERR_PTR(-EINVAL);
435 
436 	guard(mutex)(&pwm_lock);
437 
438 	pwm = &chip->pwms[index];
439 
440 	err = pwm_device_request(pwm, label);
441 	if (err < 0)
442 		return ERR_PTR(err);
443 
444 	return pwm;
445 }
446 
447 struct pwm_device *
448 of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
449 {
450 	struct pwm_device *pwm;
451 
452 	/* period in the second cell and flags in the third cell are optional */
453 	if (args->args_count < 1)
454 		return ERR_PTR(-EINVAL);
455 
456 	pwm = pwm_request_from_chip(chip, args->args[0], NULL);
457 	if (IS_ERR(pwm))
458 		return pwm;
459 
460 	if (args->args_count > 1)
461 		pwm->args.period = args->args[1];
462 
463 	pwm->args.polarity = PWM_POLARITY_NORMAL;
464 	if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
465 		pwm->args.polarity = PWM_POLARITY_INVERSED;
466 
467 	return pwm;
468 }
469 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
470 
471 struct pwm_device *
472 of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
473 {
474 	struct pwm_device *pwm;
475 
476 	pwm = pwm_request_from_chip(chip, 0, NULL);
477 	if (IS_ERR(pwm))
478 		return pwm;
479 
480 	if (args->args_count > 0)
481 		pwm->args.period = args->args[0];
482 
483 	pwm->args.polarity = PWM_POLARITY_NORMAL;
484 	if (args->args_count > 1 && args->args[1] & PWM_POLARITY_INVERTED)
485 		pwm->args.polarity = PWM_POLARITY_INVERSED;
486 
487 	return pwm;
488 }
489 EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
490 
491 struct pwm_export {
492 	struct device pwm_dev;
493 	struct pwm_device *pwm;
494 	struct mutex lock;
495 	struct pwm_state suspend;
496 };
497 
498 static inline struct pwm_chip *pwmchip_from_dev(struct device *pwmchip_dev)
499 {
500 	return container_of(pwmchip_dev, struct pwm_chip, dev);
501 }
502 
503 static inline struct pwm_export *pwmexport_from_dev(struct device *pwm_dev)
504 {
505 	return container_of(pwm_dev, struct pwm_export, pwm_dev);
506 }
507 
508 static inline struct pwm_device *pwm_from_dev(struct device *pwm_dev)
509 {
510 	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
511 
512 	return export->pwm;
513 }
514 
515 static ssize_t period_show(struct device *pwm_dev,
516 			   struct device_attribute *attr,
517 			   char *buf)
518 {
519 	const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
520 	struct pwm_state state;
521 
522 	pwm_get_state(pwm, &state);
523 
524 	return sysfs_emit(buf, "%llu\n", state.period);
525 }
526 
527 static ssize_t period_store(struct device *pwm_dev,
528 			    struct device_attribute *attr,
529 			    const char *buf, size_t size)
530 {
531 	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
532 	struct pwm_device *pwm = export->pwm;
533 	struct pwm_state state;
534 	u64 val;
535 	int ret;
536 
537 	ret = kstrtou64(buf, 0, &val);
538 	if (ret)
539 		return ret;
540 
541 	guard(mutex)(&export->lock);
542 
543 	pwm_get_state(pwm, &state);
544 	state.period = val;
545 	ret = pwm_apply_might_sleep(pwm, &state);
546 
547 	return ret ? : size;
548 }
549 
550 static ssize_t duty_cycle_show(struct device *pwm_dev,
551 			       struct device_attribute *attr,
552 			       char *buf)
553 {
554 	const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
555 	struct pwm_state state;
556 
557 	pwm_get_state(pwm, &state);
558 
559 	return sysfs_emit(buf, "%llu\n", state.duty_cycle);
560 }
561 
562 static ssize_t duty_cycle_store(struct device *pwm_dev,
563 				struct device_attribute *attr,
564 				const char *buf, size_t size)
565 {
566 	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
567 	struct pwm_device *pwm = export->pwm;
568 	struct pwm_state state;
569 	u64 val;
570 	int ret;
571 
572 	ret = kstrtou64(buf, 0, &val);
573 	if (ret)
574 		return ret;
575 
576 	guard(mutex)(&export->lock);
577 
578 	pwm_get_state(pwm, &state);
579 	state.duty_cycle = val;
580 	ret = pwm_apply_might_sleep(pwm, &state);
581 
582 	return ret ? : size;
583 }
584 
585 static ssize_t enable_show(struct device *pwm_dev,
586 			   struct device_attribute *attr,
587 			   char *buf)
588 {
589 	const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
590 	struct pwm_state state;
591 
592 	pwm_get_state(pwm, &state);
593 
594 	return sysfs_emit(buf, "%d\n", state.enabled);
595 }
596 
597 static ssize_t enable_store(struct device *pwm_dev,
598 			    struct device_attribute *attr,
599 			    const char *buf, size_t size)
600 {
601 	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
602 	struct pwm_device *pwm = export->pwm;
603 	struct pwm_state state;
604 	int val, ret;
605 
606 	ret = kstrtoint(buf, 0, &val);
607 	if (ret)
608 		return ret;
609 
610 	guard(mutex)(&export->lock);
611 
612 	pwm_get_state(pwm, &state);
613 
614 	switch (val) {
615 	case 0:
616 		state.enabled = false;
617 		break;
618 	case 1:
619 		state.enabled = true;
620 		break;
621 	default:
622 		return -EINVAL;
623 	}
624 
625 	ret = pwm_apply_might_sleep(pwm, &state);
626 
627 	return ret ? : size;
628 }
629 
630 static ssize_t polarity_show(struct device *pwm_dev,
631 			     struct device_attribute *attr,
632 			     char *buf)
633 {
634 	const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
635 	const char *polarity = "unknown";
636 	struct pwm_state state;
637 
638 	pwm_get_state(pwm, &state);
639 
640 	switch (state.polarity) {
641 	case PWM_POLARITY_NORMAL:
642 		polarity = "normal";
643 		break;
644 
645 	case PWM_POLARITY_INVERSED:
646 		polarity = "inversed";
647 		break;
648 	}
649 
650 	return sysfs_emit(buf, "%s\n", polarity);
651 }
652 
653 static ssize_t polarity_store(struct device *pwm_dev,
654 			      struct device_attribute *attr,
655 			      const char *buf, size_t size)
656 {
657 	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
658 	struct pwm_device *pwm = export->pwm;
659 	enum pwm_polarity polarity;
660 	struct pwm_state state;
661 	int ret;
662 
663 	if (sysfs_streq(buf, "normal"))
664 		polarity = PWM_POLARITY_NORMAL;
665 	else if (sysfs_streq(buf, "inversed"))
666 		polarity = PWM_POLARITY_INVERSED;
667 	else
668 		return -EINVAL;
669 
670 	guard(mutex)(&export->lock);
671 
672 	pwm_get_state(pwm, &state);
673 	state.polarity = polarity;
674 	ret = pwm_apply_might_sleep(pwm, &state);
675 
676 	return ret ? : size;
677 }
678 
679 static ssize_t capture_show(struct device *pwm_dev,
680 			    struct device_attribute *attr,
681 			    char *buf)
682 {
683 	struct pwm_device *pwm = pwm_from_dev(pwm_dev);
684 	struct pwm_capture result;
685 	int ret;
686 
687 	ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
688 	if (ret)
689 		return ret;
690 
691 	return sysfs_emit(buf, "%u %u\n", result.period, result.duty_cycle);
692 }
693 
694 static DEVICE_ATTR_RW(period);
695 static DEVICE_ATTR_RW(duty_cycle);
696 static DEVICE_ATTR_RW(enable);
697 static DEVICE_ATTR_RW(polarity);
698 static DEVICE_ATTR_RO(capture);
699 
700 static struct attribute *pwm_attrs[] = {
701 	&dev_attr_period.attr,
702 	&dev_attr_duty_cycle.attr,
703 	&dev_attr_enable.attr,
704 	&dev_attr_polarity.attr,
705 	&dev_attr_capture.attr,
706 	NULL
707 };
708 ATTRIBUTE_GROUPS(pwm);
709 
710 static void pwm_export_release(struct device *pwm_dev)
711 {
712 	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
713 
714 	kfree(export);
715 }
716 
717 static int pwm_export_child(struct device *pwmchip_dev, struct pwm_device *pwm)
718 {
719 	struct pwm_export *export;
720 	char *pwm_prop[2];
721 	int ret;
722 
723 	if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
724 		return -EBUSY;
725 
726 	export = kzalloc(sizeof(*export), GFP_KERNEL);
727 	if (!export) {
728 		clear_bit(PWMF_EXPORTED, &pwm->flags);
729 		return -ENOMEM;
730 	}
731 
732 	export->pwm = pwm;
733 	mutex_init(&export->lock);
734 
735 	export->pwm_dev.release = pwm_export_release;
736 	export->pwm_dev.parent = pwmchip_dev;
737 	export->pwm_dev.devt = MKDEV(0, 0);
738 	export->pwm_dev.groups = pwm_groups;
739 	dev_set_name(&export->pwm_dev, "pwm%u", pwm->hwpwm);
740 
741 	ret = device_register(&export->pwm_dev);
742 	if (ret) {
743 		clear_bit(PWMF_EXPORTED, &pwm->flags);
744 		put_device(&export->pwm_dev);
745 		export = NULL;
746 		return ret;
747 	}
748 	pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
749 	pwm_prop[1] = NULL;
750 	kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
751 	kfree(pwm_prop[0]);
752 
753 	return 0;
754 }
755 
756 static int pwm_unexport_match(struct device *pwm_dev, void *data)
757 {
758 	return pwm_from_dev(pwm_dev) == data;
759 }
760 
761 static int pwm_unexport_child(struct device *pwmchip_dev, struct pwm_device *pwm)
762 {
763 	struct device *pwm_dev;
764 	char *pwm_prop[2];
765 
766 	if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
767 		return -ENODEV;
768 
769 	pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
770 	if (!pwm_dev)
771 		return -ENODEV;
772 
773 	pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
774 	pwm_prop[1] = NULL;
775 	kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
776 	kfree(pwm_prop[0]);
777 
778 	/* for device_find_child() */
779 	put_device(pwm_dev);
780 	device_unregister(pwm_dev);
781 	pwm_put(pwm);
782 
783 	return 0;
784 }
785 
786 static ssize_t export_store(struct device *pwmchip_dev,
787 			    struct device_attribute *attr,
788 			    const char *buf, size_t len)
789 {
790 	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
791 	struct pwm_device *pwm;
792 	unsigned int hwpwm;
793 	int ret;
794 
795 	ret = kstrtouint(buf, 0, &hwpwm);
796 	if (ret < 0)
797 		return ret;
798 
799 	if (hwpwm >= chip->npwm)
800 		return -ENODEV;
801 
802 	pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
803 	if (IS_ERR(pwm))
804 		return PTR_ERR(pwm);
805 
806 	ret = pwm_export_child(pwmchip_dev, pwm);
807 	if (ret < 0)
808 		pwm_put(pwm);
809 
810 	return ret ? : len;
811 }
812 static DEVICE_ATTR_WO(export);
813 
814 static ssize_t unexport_store(struct device *pwmchip_dev,
815 			      struct device_attribute *attr,
816 			      const char *buf, size_t len)
817 {
818 	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
819 	unsigned int hwpwm;
820 	int ret;
821 
822 	ret = kstrtouint(buf, 0, &hwpwm);
823 	if (ret < 0)
824 		return ret;
825 
826 	if (hwpwm >= chip->npwm)
827 		return -ENODEV;
828 
829 	ret = pwm_unexport_child(pwmchip_dev, &chip->pwms[hwpwm]);
830 
831 	return ret ? : len;
832 }
833 static DEVICE_ATTR_WO(unexport);
834 
835 static ssize_t npwm_show(struct device *pwmchip_dev, struct device_attribute *attr,
836 			 char *buf)
837 {
838 	const struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
839 
840 	return sysfs_emit(buf, "%u\n", chip->npwm);
841 }
842 static DEVICE_ATTR_RO(npwm);
843 
844 static struct attribute *pwm_chip_attrs[] = {
845 	&dev_attr_export.attr,
846 	&dev_attr_unexport.attr,
847 	&dev_attr_npwm.attr,
848 	NULL,
849 };
850 ATTRIBUTE_GROUPS(pwm_chip);
851 
852 /* takes export->lock on success */
853 static struct pwm_export *pwm_class_get_state(struct device *pwmchip_dev,
854 					      struct pwm_device *pwm,
855 					      struct pwm_state *state)
856 {
857 	struct device *pwm_dev;
858 	struct pwm_export *export;
859 
860 	if (!test_bit(PWMF_EXPORTED, &pwm->flags))
861 		return NULL;
862 
863 	pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
864 	if (!pwm_dev)
865 		return NULL;
866 
867 	export = pwmexport_from_dev(pwm_dev);
868 	put_device(pwm_dev);	/* for device_find_child() */
869 
870 	mutex_lock(&export->lock);
871 	pwm_get_state(pwm, state);
872 
873 	return export;
874 }
875 
876 static int pwm_class_apply_state(struct pwm_export *export,
877 				 struct pwm_device *pwm,
878 				 struct pwm_state *state)
879 {
880 	int ret = pwm_apply_might_sleep(pwm, state);
881 
882 	/* release lock taken in pwm_class_get_state */
883 	mutex_unlock(&export->lock);
884 
885 	return ret;
886 }
887 
888 static int pwm_class_resume_npwm(struct device *pwmchip_dev, unsigned int npwm)
889 {
890 	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
891 	unsigned int i;
892 	int ret = 0;
893 
894 	for (i = 0; i < npwm; i++) {
895 		struct pwm_device *pwm = &chip->pwms[i];
896 		struct pwm_state state;
897 		struct pwm_export *export;
898 
899 		export = pwm_class_get_state(pwmchip_dev, pwm, &state);
900 		if (!export)
901 			continue;
902 
903 		/* If pwmchip was not enabled before suspend, do nothing. */
904 		if (!export->suspend.enabled) {
905 			/* release lock taken in pwm_class_get_state */
906 			mutex_unlock(&export->lock);
907 			continue;
908 		}
909 
910 		state.enabled = export->suspend.enabled;
911 		ret = pwm_class_apply_state(export, pwm, &state);
912 		if (ret < 0)
913 			break;
914 	}
915 
916 	return ret;
917 }
918 
919 static int pwm_class_suspend(struct device *pwmchip_dev)
920 {
921 	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
922 	unsigned int i;
923 	int ret = 0;
924 
925 	for (i = 0; i < chip->npwm; i++) {
926 		struct pwm_device *pwm = &chip->pwms[i];
927 		struct pwm_state state;
928 		struct pwm_export *export;
929 
930 		export = pwm_class_get_state(pwmchip_dev, pwm, &state);
931 		if (!export)
932 			continue;
933 
934 		/*
935 		 * If pwmchip was not enabled before suspend, save
936 		 * state for resume time and do nothing else.
937 		 */
938 		export->suspend = state;
939 		if (!state.enabled) {
940 			/* release lock taken in pwm_class_get_state */
941 			mutex_unlock(&export->lock);
942 			continue;
943 		}
944 
945 		state.enabled = false;
946 		ret = pwm_class_apply_state(export, pwm, &state);
947 		if (ret < 0) {
948 			/*
949 			 * roll back the PWM devices that were disabled by
950 			 * this suspend function.
951 			 */
952 			pwm_class_resume_npwm(pwmchip_dev, i);
953 			break;
954 		}
955 	}
956 
957 	return ret;
958 }
959 
960 static int pwm_class_resume(struct device *pwmchip_dev)
961 {
962 	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
963 
964 	return pwm_class_resume_npwm(pwmchip_dev, chip->npwm);
965 }
966 
967 static DEFINE_SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
968 
969 static struct class pwm_class = {
970 	.name = "pwm",
971 	.dev_groups = pwm_chip_groups,
972 	.pm = pm_sleep_ptr(&pwm_class_pm_ops),
973 };
974 
975 static void pwmchip_sysfs_unexport(struct pwm_chip *chip)
976 {
977 	unsigned int i;
978 
979 	for (i = 0; i < chip->npwm; i++) {
980 		struct pwm_device *pwm = &chip->pwms[i];
981 
982 		if (test_bit(PWMF_EXPORTED, &pwm->flags))
983 			pwm_unexport_child(&chip->dev, pwm);
984 	}
985 }
986 
987 #define PWMCHIP_ALIGN ARCH_DMA_MINALIGN
988 
989 static void *pwmchip_priv(struct pwm_chip *chip)
990 {
991 	return (void *)chip + ALIGN(struct_size(chip, pwms, chip->npwm), PWMCHIP_ALIGN);
992 }
993 
994 /* This is the counterpart to pwmchip_alloc() */
995 void pwmchip_put(struct pwm_chip *chip)
996 {
997 	put_device(&chip->dev);
998 }
999 EXPORT_SYMBOL_GPL(pwmchip_put);
1000 
1001 static void pwmchip_release(struct device *pwmchip_dev)
1002 {
1003 	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
1004 
1005 	kfree(chip);
1006 }
1007 
1008 struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
1009 {
1010 	struct pwm_chip *chip;
1011 	struct device *pwmchip_dev;
1012 	size_t alloc_size;
1013 	unsigned int i;
1014 
1015 	alloc_size = size_add(ALIGN(struct_size(chip, pwms, npwm), PWMCHIP_ALIGN),
1016 			      sizeof_priv);
1017 
1018 	chip = kzalloc(alloc_size, GFP_KERNEL);
1019 	if (!chip)
1020 		return ERR_PTR(-ENOMEM);
1021 
1022 	chip->npwm = npwm;
1023 	chip->uses_pwmchip_alloc = true;
1024 
1025 	pwmchip_dev = &chip->dev;
1026 	device_initialize(pwmchip_dev);
1027 	pwmchip_dev->class = &pwm_class;
1028 	pwmchip_dev->parent = parent;
1029 	pwmchip_dev->release = pwmchip_release;
1030 
1031 	pwmchip_set_drvdata(chip, pwmchip_priv(chip));
1032 
1033 	for (i = 0; i < chip->npwm; i++) {
1034 		struct pwm_device *pwm = &chip->pwms[i];
1035 		pwm->chip = chip;
1036 		pwm->hwpwm = i;
1037 	}
1038 
1039 	return chip;
1040 }
1041 EXPORT_SYMBOL_GPL(pwmchip_alloc);
1042 
1043 static void devm_pwmchip_put(void *data)
1044 {
1045 	struct pwm_chip *chip = data;
1046 
1047 	pwmchip_put(chip);
1048 }
1049 
1050 struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
1051 {
1052 	struct pwm_chip *chip;
1053 	int ret;
1054 
1055 	chip = pwmchip_alloc(parent, npwm, sizeof_priv);
1056 	if (IS_ERR(chip))
1057 		return chip;
1058 
1059 	ret = devm_add_action_or_reset(parent, devm_pwmchip_put, chip);
1060 	if (ret)
1061 		return ERR_PTR(ret);
1062 
1063 	return chip;
1064 }
1065 EXPORT_SYMBOL_GPL(devm_pwmchip_alloc);
1066 
1067 static void of_pwmchip_add(struct pwm_chip *chip)
1068 {
1069 	if (!pwmchip_parent(chip) || !pwmchip_parent(chip)->of_node)
1070 		return;
1071 
1072 	if (!chip->of_xlate)
1073 		chip->of_xlate = of_pwm_xlate_with_flags;
1074 
1075 	of_node_get(pwmchip_parent(chip)->of_node);
1076 }
1077 
1078 static void of_pwmchip_remove(struct pwm_chip *chip)
1079 {
1080 	if (pwmchip_parent(chip))
1081 		of_node_put(pwmchip_parent(chip)->of_node);
1082 }
1083 
1084 static bool pwm_ops_check(const struct pwm_chip *chip)
1085 {
1086 	const struct pwm_ops *ops = chip->ops;
1087 
1088 	if (!ops->apply)
1089 		return false;
1090 
1091 	if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
1092 		dev_warn(pwmchip_parent(chip),
1093 			 "Please implement the .get_state() callback\n");
1094 
1095 	return true;
1096 }
1097 
1098 /**
1099  * __pwmchip_add() - register a new PWM chip
1100  * @chip: the PWM chip to add
1101  * @owner: reference to the module providing the chip.
1102  *
1103  * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
1104  * pwmchip_add wrapper to do this right.
1105  *
1106  * Returns: 0 on success or a negative error code on failure.
1107  */
1108 int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
1109 {
1110 	int ret;
1111 
1112 	if (!chip || !pwmchip_parent(chip) || !chip->ops || !chip->npwm)
1113 		return -EINVAL;
1114 
1115 	/*
1116 	 * a struct pwm_chip must be allocated using (devm_)pwmchip_alloc,
1117 	 * otherwise the embedded struct device might disappear too early
1118 	 * resulting in memory corruption.
1119 	 * Catch drivers that were not converted appropriately.
1120 	 */
1121 	if (!chip->uses_pwmchip_alloc)
1122 		return -EINVAL;
1123 
1124 	if (!pwm_ops_check(chip))
1125 		return -EINVAL;
1126 
1127 	chip->owner = owner;
1128 
1129 	guard(mutex)(&pwm_lock);
1130 
1131 	ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
1132 	if (ret < 0)
1133 		return ret;
1134 
1135 	chip->id = ret;
1136 
1137 	dev_set_name(&chip->dev, "pwmchip%u", chip->id);
1138 
1139 	if (IS_ENABLED(CONFIG_OF))
1140 		of_pwmchip_add(chip);
1141 
1142 	ret = device_add(&chip->dev);
1143 	if (ret)
1144 		goto err_device_add;
1145 
1146 	return 0;
1147 
1148 err_device_add:
1149 	if (IS_ENABLED(CONFIG_OF))
1150 		of_pwmchip_remove(chip);
1151 
1152 	idr_remove(&pwm_chips, chip->id);
1153 
1154 	return ret;
1155 }
1156 EXPORT_SYMBOL_GPL(__pwmchip_add);
1157 
1158 /**
1159  * pwmchip_remove() - remove a PWM chip
1160  * @chip: the PWM chip to remove
1161  *
1162  * Removes a PWM chip.
1163  */
1164 void pwmchip_remove(struct pwm_chip *chip)
1165 {
1166 	pwmchip_sysfs_unexport(chip);
1167 
1168 	if (IS_ENABLED(CONFIG_OF))
1169 		of_pwmchip_remove(chip);
1170 
1171 	scoped_guard(mutex, &pwm_lock)
1172 		idr_remove(&pwm_chips, chip->id);
1173 
1174 	device_del(&chip->dev);
1175 }
1176 EXPORT_SYMBOL_GPL(pwmchip_remove);
1177 
1178 static void devm_pwmchip_remove(void *data)
1179 {
1180 	struct pwm_chip *chip = data;
1181 
1182 	pwmchip_remove(chip);
1183 }
1184 
1185 int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
1186 {
1187 	int ret;
1188 
1189 	ret = __pwmchip_add(chip, owner);
1190 	if (ret)
1191 		return ret;
1192 
1193 	return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
1194 }
1195 EXPORT_SYMBOL_GPL(__devm_pwmchip_add);
1196 
1197 static struct device_link *pwm_device_link_add(struct device *dev,
1198 					       struct pwm_device *pwm)
1199 {
1200 	struct device_link *dl;
1201 
1202 	if (!dev) {
1203 		/*
1204 		 * No device for the PWM consumer has been provided. It may
1205 		 * impact the PM sequence ordering: the PWM supplier may get
1206 		 * suspended before the consumer.
1207 		 */
1208 		dev_warn(pwmchip_parent(pwm->chip),
1209 			 "No consumer device specified to create a link to\n");
1210 		return NULL;
1211 	}
1212 
1213 	dl = device_link_add(dev, pwmchip_parent(pwm->chip), DL_FLAG_AUTOREMOVE_CONSUMER);
1214 	if (!dl) {
1215 		dev_err(dev, "failed to create device link to %s\n",
1216 			dev_name(pwmchip_parent(pwm->chip)));
1217 		return ERR_PTR(-EINVAL);
1218 	}
1219 
1220 	return dl;
1221 }
1222 
1223 static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
1224 {
1225 	struct pwm_chip *chip;
1226 	unsigned long id, tmp;
1227 
1228 	guard(mutex)(&pwm_lock);
1229 
1230 	idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
1231 		if (pwmchip_parent(chip) && device_match_fwnode(pwmchip_parent(chip), fwnode))
1232 			return chip;
1233 
1234 	return ERR_PTR(-EPROBE_DEFER);
1235 }
1236 
1237 /**
1238  * of_pwm_get() - request a PWM via the PWM framework
1239  * @dev: device for PWM consumer
1240  * @np: device node to get the PWM from
1241  * @con_id: consumer name
1242  *
1243  * Returns the PWM device parsed from the phandle and index specified in the
1244  * "pwms" property of a device tree node or a negative error-code on failure.
1245  * Values parsed from the device tree are stored in the returned PWM device
1246  * object.
1247  *
1248  * If con_id is NULL, the first PWM device listed in the "pwms" property will
1249  * be requested. Otherwise the "pwm-names" property is used to do a reverse
1250  * lookup of the PWM index. This also means that the "pwm-names" property
1251  * becomes mandatory for devices that look up the PWM device via the con_id
1252  * parameter.
1253  *
1254  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1255  * error code on failure.
1256  */
1257 static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
1258 				     const char *con_id)
1259 {
1260 	struct pwm_device *pwm = NULL;
1261 	struct of_phandle_args args;
1262 	struct device_link *dl;
1263 	struct pwm_chip *chip;
1264 	int index = 0;
1265 	int err;
1266 
1267 	if (con_id) {
1268 		index = of_property_match_string(np, "pwm-names", con_id);
1269 		if (index < 0)
1270 			return ERR_PTR(index);
1271 	}
1272 
1273 	err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
1274 					 &args);
1275 	if (err) {
1276 		pr_err("%s(): can't parse \"pwms\" property\n", __func__);
1277 		return ERR_PTR(err);
1278 	}
1279 
1280 	chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
1281 	if (IS_ERR(chip)) {
1282 		if (PTR_ERR(chip) != -EPROBE_DEFER)
1283 			pr_err("%s(): PWM chip not found\n", __func__);
1284 
1285 		pwm = ERR_CAST(chip);
1286 		goto put;
1287 	}
1288 
1289 	pwm = chip->of_xlate(chip, &args);
1290 	if (IS_ERR(pwm))
1291 		goto put;
1292 
1293 	dl = pwm_device_link_add(dev, pwm);
1294 	if (IS_ERR(dl)) {
1295 		/* of_xlate ended up calling pwm_request_from_chip() */
1296 		pwm_put(pwm);
1297 		pwm = ERR_CAST(dl);
1298 		goto put;
1299 	}
1300 
1301 	/*
1302 	 * If a consumer name was not given, try to look it up from the
1303 	 * "pwm-names" property if it exists. Otherwise use the name of
1304 	 * the user device node.
1305 	 */
1306 	if (!con_id) {
1307 		err = of_property_read_string_index(np, "pwm-names", index,
1308 						    &con_id);
1309 		if (err < 0)
1310 			con_id = np->name;
1311 	}
1312 
1313 	pwm->label = con_id;
1314 
1315 put:
1316 	of_node_put(args.np);
1317 
1318 	return pwm;
1319 }
1320 
1321 /**
1322  * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
1323  * @fwnode: firmware node to get the "pwms" property from
1324  *
1325  * Returns the PWM device parsed from the fwnode and index specified in the
1326  * "pwms" property or a negative error-code on failure.
1327  * Values parsed from the device tree are stored in the returned PWM device
1328  * object.
1329  *
1330  * This is analogous to of_pwm_get() except con_id is not yet supported.
1331  * ACPI entries must look like
1332  * Package () {"pwms", Package ()
1333  *     { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
1334  *
1335  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1336  * error code on failure.
1337  */
1338 static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
1339 {
1340 	struct pwm_device *pwm;
1341 	struct fwnode_reference_args args;
1342 	struct pwm_chip *chip;
1343 	int ret;
1344 
1345 	memset(&args, 0, sizeof(args));
1346 
1347 	ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
1348 	if (ret < 0)
1349 		return ERR_PTR(ret);
1350 
1351 	if (args.nargs < 2)
1352 		return ERR_PTR(-EPROTO);
1353 
1354 	chip = fwnode_to_pwmchip(args.fwnode);
1355 	if (IS_ERR(chip))
1356 		return ERR_CAST(chip);
1357 
1358 	pwm = pwm_request_from_chip(chip, args.args[0], NULL);
1359 	if (IS_ERR(pwm))
1360 		return pwm;
1361 
1362 	pwm->args.period = args.args[1];
1363 	pwm->args.polarity = PWM_POLARITY_NORMAL;
1364 
1365 	if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
1366 		pwm->args.polarity = PWM_POLARITY_INVERSED;
1367 
1368 	return pwm;
1369 }
1370 
1371 static DEFINE_MUTEX(pwm_lookup_lock);
1372 static LIST_HEAD(pwm_lookup_list);
1373 
1374 /**
1375  * pwm_add_table() - register PWM device consumers
1376  * @table: array of consumers to register
1377  * @num: number of consumers in table
1378  */
1379 void pwm_add_table(struct pwm_lookup *table, size_t num)
1380 {
1381 	guard(mutex)(&pwm_lookup_lock);
1382 
1383 	while (num--) {
1384 		list_add_tail(&table->list, &pwm_lookup_list);
1385 		table++;
1386 	}
1387 }
1388 
1389 /**
1390  * pwm_remove_table() - unregister PWM device consumers
1391  * @table: array of consumers to unregister
1392  * @num: number of consumers in table
1393  */
1394 void pwm_remove_table(struct pwm_lookup *table, size_t num)
1395 {
1396 	guard(mutex)(&pwm_lookup_lock);
1397 
1398 	while (num--) {
1399 		list_del(&table->list);
1400 		table++;
1401 	}
1402 }
1403 
1404 /**
1405  * pwm_get() - look up and request a PWM device
1406  * @dev: device for PWM consumer
1407  * @con_id: consumer name
1408  *
1409  * Lookup is first attempted using DT. If the device was not instantiated from
1410  * a device tree, a PWM chip and a relative index is looked up via a table
1411  * supplied by board setup code (see pwm_add_table()).
1412  *
1413  * Once a PWM chip has been found the specified PWM device will be requested
1414  * and is ready to be used.
1415  *
1416  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1417  * error code on failure.
1418  */
1419 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
1420 {
1421 	const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
1422 	const char *dev_id = dev ? dev_name(dev) : NULL;
1423 	struct pwm_device *pwm;
1424 	struct pwm_chip *chip;
1425 	struct device_link *dl;
1426 	unsigned int best = 0;
1427 	struct pwm_lookup *p, *chosen = NULL;
1428 	unsigned int match;
1429 	int err;
1430 
1431 	/* look up via DT first */
1432 	if (is_of_node(fwnode))
1433 		return of_pwm_get(dev, to_of_node(fwnode), con_id);
1434 
1435 	/* then lookup via ACPI */
1436 	if (is_acpi_node(fwnode)) {
1437 		pwm = acpi_pwm_get(fwnode);
1438 		if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
1439 			return pwm;
1440 	}
1441 
1442 	/*
1443 	 * We look up the provider in the static table typically provided by
1444 	 * board setup code. We first try to lookup the consumer device by
1445 	 * name. If the consumer device was passed in as NULL or if no match
1446 	 * was found, we try to find the consumer by directly looking it up
1447 	 * by name.
1448 	 *
1449 	 * If a match is found, the provider PWM chip is looked up by name
1450 	 * and a PWM device is requested using the PWM device per-chip index.
1451 	 *
1452 	 * The lookup algorithm was shamelessly taken from the clock
1453 	 * framework:
1454 	 *
1455 	 * We do slightly fuzzy matching here:
1456 	 *  An entry with a NULL ID is assumed to be a wildcard.
1457 	 *  If an entry has a device ID, it must match
1458 	 *  If an entry has a connection ID, it must match
1459 	 * Then we take the most specific entry - with the following order
1460 	 * of precedence: dev+con > dev only > con only.
1461 	 */
1462 	scoped_guard(mutex, &pwm_lookup_lock)
1463 		list_for_each_entry(p, &pwm_lookup_list, list) {
1464 			match = 0;
1465 
1466 			if (p->dev_id) {
1467 				if (!dev_id || strcmp(p->dev_id, dev_id))
1468 					continue;
1469 
1470 				match += 2;
1471 			}
1472 
1473 			if (p->con_id) {
1474 				if (!con_id || strcmp(p->con_id, con_id))
1475 					continue;
1476 
1477 				match += 1;
1478 			}
1479 
1480 			if (match > best) {
1481 				chosen = p;
1482 
1483 				if (match != 3)
1484 					best = match;
1485 				else
1486 					break;
1487 			}
1488 		}
1489 
1490 	if (!chosen)
1491 		return ERR_PTR(-ENODEV);
1492 
1493 	chip = pwmchip_find_by_name(chosen->provider);
1494 
1495 	/*
1496 	 * If the lookup entry specifies a module, load the module and retry
1497 	 * the PWM chip lookup. This can be used to work around driver load
1498 	 * ordering issues if driver's can't be made to properly support the
1499 	 * deferred probe mechanism.
1500 	 */
1501 	if (!chip && chosen->module) {
1502 		err = request_module(chosen->module);
1503 		if (err == 0)
1504 			chip = pwmchip_find_by_name(chosen->provider);
1505 	}
1506 
1507 	if (!chip)
1508 		return ERR_PTR(-EPROBE_DEFER);
1509 
1510 	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1511 	if (IS_ERR(pwm))
1512 		return pwm;
1513 
1514 	dl = pwm_device_link_add(dev, pwm);
1515 	if (IS_ERR(dl)) {
1516 		pwm_put(pwm);
1517 		return ERR_CAST(dl);
1518 	}
1519 
1520 	pwm->args.period = chosen->period;
1521 	pwm->args.polarity = chosen->polarity;
1522 
1523 	return pwm;
1524 }
1525 EXPORT_SYMBOL_GPL(pwm_get);
1526 
1527 /**
1528  * pwm_put() - release a PWM device
1529  * @pwm: PWM device
1530  */
1531 void pwm_put(struct pwm_device *pwm)
1532 {
1533 	struct pwm_chip *chip;
1534 
1535 	if (!pwm)
1536 		return;
1537 
1538 	chip = pwm->chip;
1539 
1540 	guard(mutex)(&pwm_lock);
1541 
1542 	if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1543 		pr_warn("PWM device already freed\n");
1544 		return;
1545 	}
1546 
1547 	if (chip->ops->free)
1548 		pwm->chip->ops->free(pwm->chip, pwm);
1549 
1550 	pwm->label = NULL;
1551 
1552 	put_device(&chip->dev);
1553 
1554 	module_put(chip->owner);
1555 }
1556 EXPORT_SYMBOL_GPL(pwm_put);
1557 
1558 static void devm_pwm_release(void *pwm)
1559 {
1560 	pwm_put(pwm);
1561 }
1562 
1563 /**
1564  * devm_pwm_get() - resource managed pwm_get()
1565  * @dev: device for PWM consumer
1566  * @con_id: consumer name
1567  *
1568  * This function performs like pwm_get() but the acquired PWM device will
1569  * automatically be released on driver detach.
1570  *
1571  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1572  * error code on failure.
1573  */
1574 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1575 {
1576 	struct pwm_device *pwm;
1577 	int ret;
1578 
1579 	pwm = pwm_get(dev, con_id);
1580 	if (IS_ERR(pwm))
1581 		return pwm;
1582 
1583 	ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1584 	if (ret)
1585 		return ERR_PTR(ret);
1586 
1587 	return pwm;
1588 }
1589 EXPORT_SYMBOL_GPL(devm_pwm_get);
1590 
1591 /**
1592  * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1593  * @dev: device for PWM consumer
1594  * @fwnode: firmware node to get the PWM from
1595  * @con_id: consumer name
1596  *
1597  * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1598  * acpi_pwm_get() for a detailed description.
1599  *
1600  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1601  * error code on failure.
1602  */
1603 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1604 				       struct fwnode_handle *fwnode,
1605 				       const char *con_id)
1606 {
1607 	struct pwm_device *pwm = ERR_PTR(-ENODEV);
1608 	int ret;
1609 
1610 	if (is_of_node(fwnode))
1611 		pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1612 	else if (is_acpi_node(fwnode))
1613 		pwm = acpi_pwm_get(fwnode);
1614 	if (IS_ERR(pwm))
1615 		return pwm;
1616 
1617 	ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1618 	if (ret)
1619 		return ERR_PTR(ret);
1620 
1621 	return pwm;
1622 }
1623 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1624 
1625 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1626 {
1627 	unsigned int i;
1628 
1629 	for (i = 0; i < chip->npwm; i++) {
1630 		struct pwm_device *pwm = &chip->pwms[i];
1631 		struct pwm_state state;
1632 
1633 		pwm_get_state(pwm, &state);
1634 
1635 		seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1636 
1637 		if (test_bit(PWMF_REQUESTED, &pwm->flags))
1638 			seq_puts(s, " requested");
1639 
1640 		if (state.enabled)
1641 			seq_puts(s, " enabled");
1642 
1643 		seq_printf(s, " period: %llu ns", state.period);
1644 		seq_printf(s, " duty: %llu ns", state.duty_cycle);
1645 		seq_printf(s, " polarity: %s",
1646 			   state.polarity ? "inverse" : "normal");
1647 
1648 		if (state.usage_power)
1649 			seq_puts(s, " usage_power");
1650 
1651 		seq_puts(s, "\n");
1652 	}
1653 }
1654 
1655 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1656 {
1657 	unsigned long id = *pos;
1658 	void *ret;
1659 
1660 	mutex_lock(&pwm_lock);
1661 	s->private = "";
1662 
1663 	ret = idr_get_next_ul(&pwm_chips, &id);
1664 	*pos = id;
1665 	return ret;
1666 }
1667 
1668 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1669 {
1670 	unsigned long id = *pos + 1;
1671 	void *ret;
1672 
1673 	s->private = "\n";
1674 
1675 	ret = idr_get_next_ul(&pwm_chips, &id);
1676 	*pos = id;
1677 	return ret;
1678 }
1679 
1680 static void pwm_seq_stop(struct seq_file *s, void *v)
1681 {
1682 	mutex_unlock(&pwm_lock);
1683 }
1684 
1685 static int pwm_seq_show(struct seq_file *s, void *v)
1686 {
1687 	struct pwm_chip *chip = v;
1688 
1689 	seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n",
1690 		   (char *)s->private, chip->id,
1691 		   pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus",
1692 		   dev_name(pwmchip_parent(chip)), chip->npwm,
1693 		   (chip->npwm != 1) ? "s" : "");
1694 
1695 	pwm_dbg_show(chip, s);
1696 
1697 	return 0;
1698 }
1699 
1700 static const struct seq_operations pwm_debugfs_sops = {
1701 	.start = pwm_seq_start,
1702 	.next = pwm_seq_next,
1703 	.stop = pwm_seq_stop,
1704 	.show = pwm_seq_show,
1705 };
1706 
1707 DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1708 
1709 static int __init pwm_init(void)
1710 {
1711 	int ret;
1712 
1713 	ret = class_register(&pwm_class);
1714 	if (ret) {
1715 		pr_err("Failed to initialize PWM class (%pe)\n", ERR_PTR(ret));
1716 		return ret;
1717 	}
1718 
1719 	if (IS_ENABLED(CONFIG_DEBUG_FS))
1720 		debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1721 
1722 	return 0;
1723 }
1724 subsys_initcall(pwm_init);
1725