xref: /openbmc/linux/drivers/pwm/core.c (revision 4eb5928d)
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 
28 static DEFINE_MUTEX(pwm_lookup_lock);
29 static LIST_HEAD(pwm_lookup_list);
30 static DEFINE_MUTEX(pwm_lock);
31 static LIST_HEAD(pwm_chips);
32 static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
33 static RADIX_TREE(pwm_tree, GFP_KERNEL);
34 
35 static struct pwm_device *pwm_to_device(unsigned int pwm)
36 {
37 	return radix_tree_lookup(&pwm_tree, pwm);
38 }
39 
40 static int alloc_pwms(int pwm, unsigned int count)
41 {
42 	unsigned int from = 0;
43 	unsigned int start;
44 
45 	if (pwm >= MAX_PWMS)
46 		return -EINVAL;
47 
48 	if (pwm >= 0)
49 		from = pwm;
50 
51 	start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
52 					   count, 0);
53 
54 	if (pwm >= 0 && start != pwm)
55 		return -EEXIST;
56 
57 	if (start + count > MAX_PWMS)
58 		return -ENOSPC;
59 
60 	return start;
61 }
62 
63 static void free_pwms(struct pwm_chip *chip)
64 {
65 	unsigned int i;
66 
67 	for (i = 0; i < chip->npwm; i++) {
68 		struct pwm_device *pwm = &chip->pwms[i];
69 
70 		radix_tree_delete(&pwm_tree, pwm->pwm);
71 	}
72 
73 	bitmap_clear(allocated_pwms, chip->base, chip->npwm);
74 
75 	kfree(chip->pwms);
76 	chip->pwms = NULL;
77 }
78 
79 static struct pwm_chip *pwmchip_find_by_name(const char *name)
80 {
81 	struct pwm_chip *chip;
82 
83 	if (!name)
84 		return NULL;
85 
86 	mutex_lock(&pwm_lock);
87 
88 	list_for_each_entry(chip, &pwm_chips, list) {
89 		const char *chip_name = dev_name(chip->dev);
90 
91 		if (chip_name && strcmp(chip_name, name) == 0) {
92 			mutex_unlock(&pwm_lock);
93 			return chip;
94 		}
95 	}
96 
97 	mutex_unlock(&pwm_lock);
98 
99 	return NULL;
100 }
101 
102 static int pwm_device_request(struct pwm_device *pwm, const char *label)
103 {
104 	int err;
105 
106 	if (test_bit(PWMF_REQUESTED, &pwm->flags))
107 		return -EBUSY;
108 
109 	if (!try_module_get(pwm->chip->ops->owner))
110 		return -ENODEV;
111 
112 	if (pwm->chip->ops->request) {
113 		err = pwm->chip->ops->request(pwm->chip, pwm);
114 		if (err) {
115 			module_put(pwm->chip->ops->owner);
116 			return err;
117 		}
118 	}
119 
120 	if (pwm->chip->ops->get_state) {
121 		pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
122 		trace_pwm_get(pwm, &pwm->state);
123 
124 		if (IS_ENABLED(CONFIG_PWM_DEBUG))
125 			pwm->last = pwm->state;
126 	}
127 
128 	set_bit(PWMF_REQUESTED, &pwm->flags);
129 	pwm->label = label;
130 
131 	return 0;
132 }
133 
134 struct pwm_device *
135 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
136 {
137 	struct pwm_device *pwm;
138 
139 	/* check, whether the driver supports a third cell for flags */
140 	if (pc->of_pwm_n_cells < 3)
141 		return ERR_PTR(-EINVAL);
142 
143 	/* flags in the third cell are optional */
144 	if (args->args_count < 2)
145 		return ERR_PTR(-EINVAL);
146 
147 	if (args->args[0] >= pc->npwm)
148 		return ERR_PTR(-EINVAL);
149 
150 	pwm = pwm_request_from_chip(pc, args->args[0], NULL);
151 	if (IS_ERR(pwm))
152 		return pwm;
153 
154 	pwm->args.period = args->args[1];
155 	pwm->args.polarity = PWM_POLARITY_NORMAL;
156 
157 	if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
158 		pwm->args.polarity = PWM_POLARITY_INVERSED;
159 
160 	return pwm;
161 }
162 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
163 
164 static struct pwm_device *
165 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
166 {
167 	struct pwm_device *pwm;
168 
169 	/* sanity check driver support */
170 	if (pc->of_pwm_n_cells < 2)
171 		return ERR_PTR(-EINVAL);
172 
173 	/* all cells are required */
174 	if (args->args_count != pc->of_pwm_n_cells)
175 		return ERR_PTR(-EINVAL);
176 
177 	if (args->args[0] >= pc->npwm)
178 		return ERR_PTR(-EINVAL);
179 
180 	pwm = pwm_request_from_chip(pc, args->args[0], NULL);
181 	if (IS_ERR(pwm))
182 		return pwm;
183 
184 	pwm->args.period = args->args[1];
185 
186 	return pwm;
187 }
188 
189 static void of_pwmchip_add(struct pwm_chip *chip)
190 {
191 	if (!chip->dev || !chip->dev->of_node)
192 		return;
193 
194 	if (!chip->of_xlate) {
195 		chip->of_xlate = of_pwm_simple_xlate;
196 		chip->of_pwm_n_cells = 2;
197 	}
198 
199 	of_node_get(chip->dev->of_node);
200 }
201 
202 static void of_pwmchip_remove(struct pwm_chip *chip)
203 {
204 	if (chip->dev)
205 		of_node_put(chip->dev->of_node);
206 }
207 
208 /**
209  * pwm_set_chip_data() - set private chip data for a PWM
210  * @pwm: PWM device
211  * @data: pointer to chip-specific data
212  *
213  * Returns: 0 on success or a negative error code on failure.
214  */
215 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
216 {
217 	if (!pwm)
218 		return -EINVAL;
219 
220 	pwm->chip_data = data;
221 
222 	return 0;
223 }
224 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
225 
226 /**
227  * pwm_get_chip_data() - get private chip data for a PWM
228  * @pwm: PWM device
229  *
230  * Returns: A pointer to the chip-private data for the PWM device.
231  */
232 void *pwm_get_chip_data(struct pwm_device *pwm)
233 {
234 	return pwm ? pwm->chip_data : NULL;
235 }
236 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
237 
238 static bool pwm_ops_check(const struct pwm_chip *chip)
239 {
240 
241 	const struct pwm_ops *ops = chip->ops;
242 
243 	/* driver supports legacy, non-atomic operation */
244 	if (ops->config && ops->enable && ops->disable) {
245 		if (IS_ENABLED(CONFIG_PWM_DEBUG))
246 			dev_warn(chip->dev,
247 				 "Driver needs updating to atomic API\n");
248 
249 		return true;
250 	}
251 
252 	if (!ops->apply)
253 		return false;
254 
255 	if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
256 		dev_warn(chip->dev,
257 			 "Please implement the .get_state() callback\n");
258 
259 	return true;
260 }
261 
262 /**
263  * pwmchip_add_with_polarity() - register a new PWM chip
264  * @chip: the PWM chip to add
265  * @polarity: initial polarity of PWM channels
266  *
267  * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
268  * will be used. The initial polarity for all channels is specified by the
269  * @polarity parameter.
270  *
271  * Returns: 0 on success or a negative error code on failure.
272  */
273 int pwmchip_add_with_polarity(struct pwm_chip *chip,
274 			      enum pwm_polarity polarity)
275 {
276 	struct pwm_device *pwm;
277 	unsigned int i;
278 	int ret;
279 
280 	if (!chip || !chip->dev || !chip->ops || !chip->npwm)
281 		return -EINVAL;
282 
283 	if (!pwm_ops_check(chip))
284 		return -EINVAL;
285 
286 	mutex_lock(&pwm_lock);
287 
288 	ret = alloc_pwms(chip->base, chip->npwm);
289 	if (ret < 0)
290 		goto out;
291 
292 	chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
293 	if (!chip->pwms) {
294 		ret = -ENOMEM;
295 		goto out;
296 	}
297 
298 	chip->base = ret;
299 
300 	for (i = 0; i < chip->npwm; i++) {
301 		pwm = &chip->pwms[i];
302 
303 		pwm->chip = chip;
304 		pwm->pwm = chip->base + i;
305 		pwm->hwpwm = i;
306 		pwm->state.polarity = polarity;
307 
308 		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
309 	}
310 
311 	bitmap_set(allocated_pwms, chip->base, chip->npwm);
312 
313 	INIT_LIST_HEAD(&chip->list);
314 	list_add(&chip->list, &pwm_chips);
315 
316 	ret = 0;
317 
318 	if (IS_ENABLED(CONFIG_OF))
319 		of_pwmchip_add(chip);
320 
321 out:
322 	mutex_unlock(&pwm_lock);
323 
324 	if (!ret)
325 		pwmchip_sysfs_export(chip);
326 
327 	return ret;
328 }
329 EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
330 
331 /**
332  * pwmchip_add() - register a new PWM chip
333  * @chip: the PWM chip to add
334  *
335  * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
336  * will be used. The initial polarity for all channels is normal.
337  *
338  * Returns: 0 on success or a negative error code on failure.
339  */
340 int pwmchip_add(struct pwm_chip *chip)
341 {
342 	return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
343 }
344 EXPORT_SYMBOL_GPL(pwmchip_add);
345 
346 /**
347  * pwmchip_remove() - remove a PWM chip
348  * @chip: the PWM chip to remove
349  *
350  * Removes a PWM chip. This function may return busy if the PWM chip provides
351  * a PWM device that is still requested.
352  *
353  * Returns: 0 on success or a negative error code on failure.
354  */
355 int pwmchip_remove(struct pwm_chip *chip)
356 {
357 	unsigned int i;
358 	int ret = 0;
359 
360 	pwmchip_sysfs_unexport(chip);
361 
362 	mutex_lock(&pwm_lock);
363 
364 	for (i = 0; i < chip->npwm; i++) {
365 		struct pwm_device *pwm = &chip->pwms[i];
366 
367 		if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
368 			ret = -EBUSY;
369 			goto out;
370 		}
371 	}
372 
373 	list_del_init(&chip->list);
374 
375 	if (IS_ENABLED(CONFIG_OF))
376 		of_pwmchip_remove(chip);
377 
378 	free_pwms(chip);
379 
380 out:
381 	mutex_unlock(&pwm_lock);
382 	return ret;
383 }
384 EXPORT_SYMBOL_GPL(pwmchip_remove);
385 
386 /**
387  * pwm_request() - request a PWM device
388  * @pwm: global PWM device index
389  * @label: PWM device label
390  *
391  * This function is deprecated, use pwm_get() instead.
392  *
393  * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
394  * failure.
395  */
396 struct pwm_device *pwm_request(int pwm, const char *label)
397 {
398 	struct pwm_device *dev;
399 	int err;
400 
401 	if (pwm < 0 || pwm >= MAX_PWMS)
402 		return ERR_PTR(-EINVAL);
403 
404 	mutex_lock(&pwm_lock);
405 
406 	dev = pwm_to_device(pwm);
407 	if (!dev) {
408 		dev = ERR_PTR(-EPROBE_DEFER);
409 		goto out;
410 	}
411 
412 	err = pwm_device_request(dev, label);
413 	if (err < 0)
414 		dev = ERR_PTR(err);
415 
416 out:
417 	mutex_unlock(&pwm_lock);
418 
419 	return dev;
420 }
421 EXPORT_SYMBOL_GPL(pwm_request);
422 
423 /**
424  * pwm_request_from_chip() - request a PWM device relative to a PWM chip
425  * @chip: PWM chip
426  * @index: per-chip index of the PWM to request
427  * @label: a literal description string of this PWM
428  *
429  * Returns: A pointer to the PWM device at the given index of the given PWM
430  * chip. A negative error code is returned if the index is not valid for the
431  * specified PWM chip or if the PWM device cannot be requested.
432  */
433 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
434 					 unsigned int index,
435 					 const char *label)
436 {
437 	struct pwm_device *pwm;
438 	int err;
439 
440 	if (!chip || index >= chip->npwm)
441 		return ERR_PTR(-EINVAL);
442 
443 	mutex_lock(&pwm_lock);
444 	pwm = &chip->pwms[index];
445 
446 	err = pwm_device_request(pwm, label);
447 	if (err < 0)
448 		pwm = ERR_PTR(err);
449 
450 	mutex_unlock(&pwm_lock);
451 	return pwm;
452 }
453 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
454 
455 /**
456  * pwm_free() - free a PWM device
457  * @pwm: PWM device
458  *
459  * This function is deprecated, use pwm_put() instead.
460  */
461 void pwm_free(struct pwm_device *pwm)
462 {
463 	pwm_put(pwm);
464 }
465 EXPORT_SYMBOL_GPL(pwm_free);
466 
467 static void pwm_apply_state_debug(struct pwm_device *pwm,
468 				  const struct pwm_state *state)
469 {
470 	struct pwm_state *last = &pwm->last;
471 	struct pwm_chip *chip = pwm->chip;
472 	struct pwm_state s1, s2;
473 	int err;
474 
475 	if (!IS_ENABLED(CONFIG_PWM_DEBUG))
476 		return;
477 
478 	/* No reasonable diagnosis possible without .get_state() */
479 	if (!chip->ops->get_state)
480 		return;
481 
482 	/*
483 	 * *state was just applied. Read out the hardware state and do some
484 	 * checks.
485 	 */
486 
487 	chip->ops->get_state(chip, pwm, &s1);
488 	trace_pwm_get(pwm, &s1);
489 
490 	/*
491 	 * The lowlevel driver either ignored .polarity (which is a bug) or as
492 	 * best effort inverted .polarity and fixed .duty_cycle respectively.
493 	 * Undo this inversion and fixup for further tests.
494 	 */
495 	if (s1.enabled && s1.polarity != state->polarity) {
496 		s2.polarity = state->polarity;
497 		s2.duty_cycle = s1.period - s1.duty_cycle;
498 		s2.period = s1.period;
499 		s2.enabled = s1.enabled;
500 	} else {
501 		s2 = s1;
502 	}
503 
504 	if (s2.polarity != state->polarity &&
505 	    state->duty_cycle < state->period)
506 		dev_warn(chip->dev, ".apply ignored .polarity\n");
507 
508 	if (state->enabled &&
509 	    last->polarity == state->polarity &&
510 	    last->period > s2.period &&
511 	    last->period <= state->period)
512 		dev_warn(chip->dev,
513 			 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
514 			 state->period, s2.period, last->period);
515 
516 	if (state->enabled && state->period < s2.period)
517 		dev_warn(chip->dev,
518 			 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
519 			 state->period, s2.period);
520 
521 	if (state->enabled &&
522 	    last->polarity == state->polarity &&
523 	    last->period == s2.period &&
524 	    last->duty_cycle > s2.duty_cycle &&
525 	    last->duty_cycle <= state->duty_cycle)
526 		dev_warn(chip->dev,
527 			 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
528 			 state->duty_cycle, state->period,
529 			 s2.duty_cycle, s2.period,
530 			 last->duty_cycle, last->period);
531 
532 	if (state->enabled && state->duty_cycle < s2.duty_cycle)
533 		dev_warn(chip->dev,
534 			 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
535 			 state->duty_cycle, state->period,
536 			 s2.duty_cycle, s2.period);
537 
538 	if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
539 		dev_warn(chip->dev,
540 			 "requested disabled, but yielded enabled with duty > 0\n");
541 
542 	/* reapply the state that the driver reported being configured. */
543 	err = chip->ops->apply(chip, pwm, &s1);
544 	if (err) {
545 		*last = s1;
546 		dev_err(chip->dev, "failed to reapply current setting\n");
547 		return;
548 	}
549 
550 	trace_pwm_apply(pwm, &s1);
551 
552 	chip->ops->get_state(chip, pwm, last);
553 	trace_pwm_get(pwm, last);
554 
555 	/* reapplication of the current state should give an exact match */
556 	if (s1.enabled != last->enabled ||
557 	    s1.polarity != last->polarity ||
558 	    (s1.enabled && s1.period != last->period) ||
559 	    (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
560 		dev_err(chip->dev,
561 			".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
562 			s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
563 			last->enabled, last->polarity, last->duty_cycle,
564 			last->period);
565 	}
566 }
567 
568 /**
569  * pwm_apply_state() - atomically apply a new state to a PWM device
570  * @pwm: PWM device
571  * @state: new state to apply
572  */
573 int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
574 {
575 	struct pwm_chip *chip;
576 	int err;
577 
578 	if (!pwm || !state || !state->period ||
579 	    state->duty_cycle > state->period)
580 		return -EINVAL;
581 
582 	chip = pwm->chip;
583 
584 	if (state->period == pwm->state.period &&
585 	    state->duty_cycle == pwm->state.duty_cycle &&
586 	    state->polarity == pwm->state.polarity &&
587 	    state->enabled == pwm->state.enabled)
588 		return 0;
589 
590 	if (chip->ops->apply) {
591 		err = chip->ops->apply(chip, pwm, state);
592 		if (err)
593 			return err;
594 
595 		trace_pwm_apply(pwm, state);
596 
597 		pwm->state = *state;
598 
599 		/*
600 		 * only do this after pwm->state was applied as some
601 		 * implementations of .get_state depend on this
602 		 */
603 		pwm_apply_state_debug(pwm, state);
604 	} else {
605 		/*
606 		 * FIXME: restore the initial state in case of error.
607 		 */
608 		if (state->polarity != pwm->state.polarity) {
609 			if (!chip->ops->set_polarity)
610 				return -ENOTSUPP;
611 
612 			/*
613 			 * Changing the polarity of a running PWM is
614 			 * only allowed when the PWM driver implements
615 			 * ->apply().
616 			 */
617 			if (pwm->state.enabled) {
618 				chip->ops->disable(chip, pwm);
619 				pwm->state.enabled = false;
620 			}
621 
622 			err = chip->ops->set_polarity(chip, pwm,
623 						      state->polarity);
624 			if (err)
625 				return err;
626 
627 			pwm->state.polarity = state->polarity;
628 		}
629 
630 		if (state->period != pwm->state.period ||
631 		    state->duty_cycle != pwm->state.duty_cycle) {
632 			err = chip->ops->config(pwm->chip, pwm,
633 						state->duty_cycle,
634 						state->period);
635 			if (err)
636 				return err;
637 
638 			pwm->state.duty_cycle = state->duty_cycle;
639 			pwm->state.period = state->period;
640 		}
641 
642 		if (state->enabled != pwm->state.enabled) {
643 			if (state->enabled) {
644 				err = chip->ops->enable(chip, pwm);
645 				if (err)
646 					return err;
647 			} else {
648 				chip->ops->disable(chip, pwm);
649 			}
650 
651 			pwm->state.enabled = state->enabled;
652 		}
653 	}
654 
655 	return 0;
656 }
657 EXPORT_SYMBOL_GPL(pwm_apply_state);
658 
659 /**
660  * pwm_capture() - capture and report a PWM signal
661  * @pwm: PWM device
662  * @result: structure to fill with capture result
663  * @timeout: time to wait, in milliseconds, before giving up on capture
664  *
665  * Returns: 0 on success or a negative error code on failure.
666  */
667 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
668 		unsigned long timeout)
669 {
670 	int err;
671 
672 	if (!pwm || !pwm->chip->ops)
673 		return -EINVAL;
674 
675 	if (!pwm->chip->ops->capture)
676 		return -ENOSYS;
677 
678 	mutex_lock(&pwm_lock);
679 	err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
680 	mutex_unlock(&pwm_lock);
681 
682 	return err;
683 }
684 EXPORT_SYMBOL_GPL(pwm_capture);
685 
686 /**
687  * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
688  * @pwm: PWM device
689  *
690  * This function will adjust the PWM config to the PWM arguments provided
691  * by the DT or PWM lookup table. This is particularly useful to adapt
692  * the bootloader config to the Linux one.
693  */
694 int pwm_adjust_config(struct pwm_device *pwm)
695 {
696 	struct pwm_state state;
697 	struct pwm_args pargs;
698 
699 	pwm_get_args(pwm, &pargs);
700 	pwm_get_state(pwm, &state);
701 
702 	/*
703 	 * If the current period is zero it means that either the PWM driver
704 	 * does not support initial state retrieval or the PWM has not yet
705 	 * been configured.
706 	 *
707 	 * In either case, we setup the new period and polarity, and assign a
708 	 * duty cycle of 0.
709 	 */
710 	if (!state.period) {
711 		state.duty_cycle = 0;
712 		state.period = pargs.period;
713 		state.polarity = pargs.polarity;
714 
715 		return pwm_apply_state(pwm, &state);
716 	}
717 
718 	/*
719 	 * Adjust the PWM duty cycle/period based on the period value provided
720 	 * in PWM args.
721 	 */
722 	if (pargs.period != state.period) {
723 		u64 dutycycle = (u64)state.duty_cycle * pargs.period;
724 
725 		do_div(dutycycle, state.period);
726 		state.duty_cycle = dutycycle;
727 		state.period = pargs.period;
728 	}
729 
730 	/*
731 	 * If the polarity changed, we should also change the duty cycle.
732 	 */
733 	if (pargs.polarity != state.polarity) {
734 		state.polarity = pargs.polarity;
735 		state.duty_cycle = state.period - state.duty_cycle;
736 	}
737 
738 	return pwm_apply_state(pwm, &state);
739 }
740 EXPORT_SYMBOL_GPL(pwm_adjust_config);
741 
742 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
743 {
744 	struct pwm_chip *chip;
745 
746 	mutex_lock(&pwm_lock);
747 
748 	list_for_each_entry(chip, &pwm_chips, list)
749 		if (chip->dev && chip->dev->of_node == np) {
750 			mutex_unlock(&pwm_lock);
751 			return chip;
752 		}
753 
754 	mutex_unlock(&pwm_lock);
755 
756 	return ERR_PTR(-EPROBE_DEFER);
757 }
758 
759 static struct device_link *pwm_device_link_add(struct device *dev,
760 					       struct pwm_device *pwm)
761 {
762 	struct device_link *dl;
763 
764 	if (!dev) {
765 		/*
766 		 * No device for the PWM consumer has been provided. It may
767 		 * impact the PM sequence ordering: the PWM supplier may get
768 		 * suspended before the consumer.
769 		 */
770 		dev_warn(pwm->chip->dev,
771 			 "No consumer device specified to create a link to\n");
772 		return NULL;
773 	}
774 
775 	dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
776 	if (!dl) {
777 		dev_err(dev, "failed to create device link to %s\n",
778 			dev_name(pwm->chip->dev));
779 		return ERR_PTR(-EINVAL);
780 	}
781 
782 	return dl;
783 }
784 
785 /**
786  * of_pwm_get() - request a PWM via the PWM framework
787  * @dev: device for PWM consumer
788  * @np: device node to get the PWM from
789  * @con_id: consumer name
790  *
791  * Returns the PWM device parsed from the phandle and index specified in the
792  * "pwms" property of a device tree node or a negative error-code on failure.
793  * Values parsed from the device tree are stored in the returned PWM device
794  * object.
795  *
796  * If con_id is NULL, the first PWM device listed in the "pwms" property will
797  * be requested. Otherwise the "pwm-names" property is used to do a reverse
798  * lookup of the PWM index. This also means that the "pwm-names" property
799  * becomes mandatory for devices that look up the PWM device via the con_id
800  * parameter.
801  *
802  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
803  * error code on failure.
804  */
805 struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
806 			      const char *con_id)
807 {
808 	struct pwm_device *pwm = NULL;
809 	struct of_phandle_args args;
810 	struct device_link *dl;
811 	struct pwm_chip *pc;
812 	int index = 0;
813 	int err;
814 
815 	if (con_id) {
816 		index = of_property_match_string(np, "pwm-names", con_id);
817 		if (index < 0)
818 			return ERR_PTR(index);
819 	}
820 
821 	err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
822 					 &args);
823 	if (err) {
824 		pr_err("%s(): can't parse \"pwms\" property\n", __func__);
825 		return ERR_PTR(err);
826 	}
827 
828 	pc = of_node_to_pwmchip(args.np);
829 	if (IS_ERR(pc)) {
830 		if (PTR_ERR(pc) != -EPROBE_DEFER)
831 			pr_err("%s(): PWM chip not found\n", __func__);
832 
833 		pwm = ERR_CAST(pc);
834 		goto put;
835 	}
836 
837 	pwm = pc->of_xlate(pc, &args);
838 	if (IS_ERR(pwm))
839 		goto put;
840 
841 	dl = pwm_device_link_add(dev, pwm);
842 	if (IS_ERR(dl)) {
843 		/* of_xlate ended up calling pwm_request_from_chip() */
844 		pwm_free(pwm);
845 		pwm = ERR_CAST(dl);
846 		goto put;
847 	}
848 
849 	/*
850 	 * If a consumer name was not given, try to look it up from the
851 	 * "pwm-names" property if it exists. Otherwise use the name of
852 	 * the user device node.
853 	 */
854 	if (!con_id) {
855 		err = of_property_read_string_index(np, "pwm-names", index,
856 						    &con_id);
857 		if (err < 0)
858 			con_id = np->name;
859 	}
860 
861 	pwm->label = con_id;
862 
863 put:
864 	of_node_put(args.np);
865 
866 	return pwm;
867 }
868 EXPORT_SYMBOL_GPL(of_pwm_get);
869 
870 #if IS_ENABLED(CONFIG_ACPI)
871 static struct pwm_chip *device_to_pwmchip(struct device *dev)
872 {
873 	struct pwm_chip *chip;
874 
875 	mutex_lock(&pwm_lock);
876 
877 	list_for_each_entry(chip, &pwm_chips, list) {
878 		struct acpi_device *adev = ACPI_COMPANION(chip->dev);
879 
880 		if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
881 			mutex_unlock(&pwm_lock);
882 			return chip;
883 		}
884 	}
885 
886 	mutex_unlock(&pwm_lock);
887 
888 	return ERR_PTR(-EPROBE_DEFER);
889 }
890 #endif
891 
892 /**
893  * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
894  * @fwnode: firmware node to get the "pwm" property from
895  *
896  * Returns the PWM device parsed from the fwnode and index specified in the
897  * "pwms" property or a negative error-code on failure.
898  * Values parsed from the device tree are stored in the returned PWM device
899  * object.
900  *
901  * This is analogous to of_pwm_get() except con_id is not yet supported.
902  * ACPI entries must look like
903  * Package () {"pwms", Package ()
904  *     { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
905  *
906  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
907  * error code on failure.
908  */
909 static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
910 {
911 	struct pwm_device *pwm = ERR_PTR(-ENODEV);
912 #if IS_ENABLED(CONFIG_ACPI)
913 	struct fwnode_reference_args args;
914 	struct acpi_device *acpi;
915 	struct pwm_chip *chip;
916 	int ret;
917 
918 	memset(&args, 0, sizeof(args));
919 
920 	ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
921 	if (ret < 0)
922 		return ERR_PTR(ret);
923 
924 	acpi = to_acpi_device_node(args.fwnode);
925 	if (!acpi)
926 		return ERR_PTR(-EINVAL);
927 
928 	if (args.nargs < 2)
929 		return ERR_PTR(-EPROTO);
930 
931 	chip = device_to_pwmchip(&acpi->dev);
932 	if (IS_ERR(chip))
933 		return ERR_CAST(chip);
934 
935 	pwm = pwm_request_from_chip(chip, args.args[0], NULL);
936 	if (IS_ERR(pwm))
937 		return pwm;
938 
939 	pwm->args.period = args.args[1];
940 	pwm->args.polarity = PWM_POLARITY_NORMAL;
941 
942 	if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
943 		pwm->args.polarity = PWM_POLARITY_INVERSED;
944 #endif
945 
946 	return pwm;
947 }
948 
949 /**
950  * pwm_add_table() - register PWM device consumers
951  * @table: array of consumers to register
952  * @num: number of consumers in table
953  */
954 void pwm_add_table(struct pwm_lookup *table, size_t num)
955 {
956 	mutex_lock(&pwm_lookup_lock);
957 
958 	while (num--) {
959 		list_add_tail(&table->list, &pwm_lookup_list);
960 		table++;
961 	}
962 
963 	mutex_unlock(&pwm_lookup_lock);
964 }
965 
966 /**
967  * pwm_remove_table() - unregister PWM device consumers
968  * @table: array of consumers to unregister
969  * @num: number of consumers in table
970  */
971 void pwm_remove_table(struct pwm_lookup *table, size_t num)
972 {
973 	mutex_lock(&pwm_lookup_lock);
974 
975 	while (num--) {
976 		list_del(&table->list);
977 		table++;
978 	}
979 
980 	mutex_unlock(&pwm_lookup_lock);
981 }
982 
983 /**
984  * pwm_get() - look up and request a PWM device
985  * @dev: device for PWM consumer
986  * @con_id: consumer name
987  *
988  * Lookup is first attempted using DT. If the device was not instantiated from
989  * a device tree, a PWM chip and a relative index is looked up via a table
990  * supplied by board setup code (see pwm_add_table()).
991  *
992  * Once a PWM chip has been found the specified PWM device will be requested
993  * and is ready to be used.
994  *
995  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
996  * error code on failure.
997  */
998 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
999 {
1000 	const char *dev_id = dev ? dev_name(dev) : NULL;
1001 	struct pwm_device *pwm;
1002 	struct pwm_chip *chip;
1003 	struct device_link *dl;
1004 	unsigned int best = 0;
1005 	struct pwm_lookup *p, *chosen = NULL;
1006 	unsigned int match;
1007 	int err;
1008 
1009 	/* look up via DT first */
1010 	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
1011 		return of_pwm_get(dev, dev->of_node, con_id);
1012 
1013 	/* then lookup via ACPI */
1014 	if (dev && is_acpi_node(dev->fwnode)) {
1015 		pwm = acpi_pwm_get(dev->fwnode);
1016 		if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
1017 			return pwm;
1018 	}
1019 
1020 	/*
1021 	 * We look up the provider in the static table typically provided by
1022 	 * board setup code. We first try to lookup the consumer device by
1023 	 * name. If the consumer device was passed in as NULL or if no match
1024 	 * was found, we try to find the consumer by directly looking it up
1025 	 * by name.
1026 	 *
1027 	 * If a match is found, the provider PWM chip is looked up by name
1028 	 * and a PWM device is requested using the PWM device per-chip index.
1029 	 *
1030 	 * The lookup algorithm was shamelessly taken from the clock
1031 	 * framework:
1032 	 *
1033 	 * We do slightly fuzzy matching here:
1034 	 *  An entry with a NULL ID is assumed to be a wildcard.
1035 	 *  If an entry has a device ID, it must match
1036 	 *  If an entry has a connection ID, it must match
1037 	 * Then we take the most specific entry - with the following order
1038 	 * of precedence: dev+con > dev only > con only.
1039 	 */
1040 	mutex_lock(&pwm_lookup_lock);
1041 
1042 	list_for_each_entry(p, &pwm_lookup_list, list) {
1043 		match = 0;
1044 
1045 		if (p->dev_id) {
1046 			if (!dev_id || strcmp(p->dev_id, dev_id))
1047 				continue;
1048 
1049 			match += 2;
1050 		}
1051 
1052 		if (p->con_id) {
1053 			if (!con_id || strcmp(p->con_id, con_id))
1054 				continue;
1055 
1056 			match += 1;
1057 		}
1058 
1059 		if (match > best) {
1060 			chosen = p;
1061 
1062 			if (match != 3)
1063 				best = match;
1064 			else
1065 				break;
1066 		}
1067 	}
1068 
1069 	mutex_unlock(&pwm_lookup_lock);
1070 
1071 	if (!chosen)
1072 		return ERR_PTR(-ENODEV);
1073 
1074 	chip = pwmchip_find_by_name(chosen->provider);
1075 
1076 	/*
1077 	 * If the lookup entry specifies a module, load the module and retry
1078 	 * the PWM chip lookup. This can be used to work around driver load
1079 	 * ordering issues if driver's can't be made to properly support the
1080 	 * deferred probe mechanism.
1081 	 */
1082 	if (!chip && chosen->module) {
1083 		err = request_module(chosen->module);
1084 		if (err == 0)
1085 			chip = pwmchip_find_by_name(chosen->provider);
1086 	}
1087 
1088 	if (!chip)
1089 		return ERR_PTR(-EPROBE_DEFER);
1090 
1091 	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1092 	if (IS_ERR(pwm))
1093 		return pwm;
1094 
1095 	dl = pwm_device_link_add(dev, pwm);
1096 	if (IS_ERR(dl)) {
1097 		pwm_free(pwm);
1098 		return ERR_CAST(dl);
1099 	}
1100 
1101 	pwm->args.period = chosen->period;
1102 	pwm->args.polarity = chosen->polarity;
1103 
1104 	return pwm;
1105 }
1106 EXPORT_SYMBOL_GPL(pwm_get);
1107 
1108 /**
1109  * pwm_put() - release a PWM device
1110  * @pwm: PWM device
1111  */
1112 void pwm_put(struct pwm_device *pwm)
1113 {
1114 	if (!pwm)
1115 		return;
1116 
1117 	mutex_lock(&pwm_lock);
1118 
1119 	if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1120 		pr_warn("PWM device already freed\n");
1121 		goto out;
1122 	}
1123 
1124 	if (pwm->chip->ops->free)
1125 		pwm->chip->ops->free(pwm->chip, pwm);
1126 
1127 	pwm_set_chip_data(pwm, NULL);
1128 	pwm->label = NULL;
1129 
1130 	module_put(pwm->chip->ops->owner);
1131 out:
1132 	mutex_unlock(&pwm_lock);
1133 }
1134 EXPORT_SYMBOL_GPL(pwm_put);
1135 
1136 static void devm_pwm_release(struct device *dev, void *res)
1137 {
1138 	pwm_put(*(struct pwm_device **)res);
1139 }
1140 
1141 /**
1142  * devm_pwm_get() - resource managed pwm_get()
1143  * @dev: device for PWM consumer
1144  * @con_id: consumer name
1145  *
1146  * This function performs like pwm_get() but the acquired PWM device will
1147  * automatically be released on driver detach.
1148  *
1149  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1150  * error code on failure.
1151  */
1152 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1153 {
1154 	struct pwm_device **ptr, *pwm;
1155 
1156 	ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1157 	if (!ptr)
1158 		return ERR_PTR(-ENOMEM);
1159 
1160 	pwm = pwm_get(dev, con_id);
1161 	if (!IS_ERR(pwm)) {
1162 		*ptr = pwm;
1163 		devres_add(dev, ptr);
1164 	} else {
1165 		devres_free(ptr);
1166 	}
1167 
1168 	return pwm;
1169 }
1170 EXPORT_SYMBOL_GPL(devm_pwm_get);
1171 
1172 /**
1173  * devm_of_pwm_get() - resource managed of_pwm_get()
1174  * @dev: device for PWM consumer
1175  * @np: device node to get the PWM from
1176  * @con_id: consumer name
1177  *
1178  * This function performs like of_pwm_get() but the acquired PWM device will
1179  * automatically be released on driver detach.
1180  *
1181  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1182  * error code on failure.
1183  */
1184 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
1185 				   const char *con_id)
1186 {
1187 	struct pwm_device **ptr, *pwm;
1188 
1189 	ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1190 	if (!ptr)
1191 		return ERR_PTR(-ENOMEM);
1192 
1193 	pwm = of_pwm_get(dev, np, con_id);
1194 	if (!IS_ERR(pwm)) {
1195 		*ptr = pwm;
1196 		devres_add(dev, ptr);
1197 	} else {
1198 		devres_free(ptr);
1199 	}
1200 
1201 	return pwm;
1202 }
1203 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
1204 
1205 /**
1206  * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1207  * @dev: device for PWM consumer
1208  * @fwnode: firmware node to get the PWM from
1209  * @con_id: consumer name
1210  *
1211  * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1212  * acpi_pwm_get() for a detailed description.
1213  *
1214  * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1215  * error code on failure.
1216  */
1217 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1218 				       struct fwnode_handle *fwnode,
1219 				       const char *con_id)
1220 {
1221 	struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV);
1222 
1223 	ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1224 	if (!ptr)
1225 		return ERR_PTR(-ENOMEM);
1226 
1227 	if (is_of_node(fwnode))
1228 		pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1229 	else if (is_acpi_node(fwnode))
1230 		pwm = acpi_pwm_get(fwnode);
1231 
1232 	if (!IS_ERR(pwm)) {
1233 		*ptr = pwm;
1234 		devres_add(dev, ptr);
1235 	} else {
1236 		devres_free(ptr);
1237 	}
1238 
1239 	return pwm;
1240 }
1241 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1242 
1243 static int devm_pwm_match(struct device *dev, void *res, void *data)
1244 {
1245 	struct pwm_device **p = res;
1246 
1247 	if (WARN_ON(!p || !*p))
1248 		return 0;
1249 
1250 	return *p == data;
1251 }
1252 
1253 /**
1254  * devm_pwm_put() - resource managed pwm_put()
1255  * @dev: device for PWM consumer
1256  * @pwm: PWM device
1257  *
1258  * Release a PWM previously allocated using devm_pwm_get(). Calling this
1259  * function is usually not needed because devm-allocated resources are
1260  * automatically released on driver detach.
1261  */
1262 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
1263 {
1264 	WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
1265 }
1266 EXPORT_SYMBOL_GPL(devm_pwm_put);
1267 
1268 #ifdef CONFIG_DEBUG_FS
1269 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1270 {
1271 	unsigned int i;
1272 
1273 	for (i = 0; i < chip->npwm; i++) {
1274 		struct pwm_device *pwm = &chip->pwms[i];
1275 		struct pwm_state state;
1276 
1277 		pwm_get_state(pwm, &state);
1278 
1279 		seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1280 
1281 		if (test_bit(PWMF_REQUESTED, &pwm->flags))
1282 			seq_puts(s, " requested");
1283 
1284 		if (state.enabled)
1285 			seq_puts(s, " enabled");
1286 
1287 		seq_printf(s, " period: %llu ns", state.period);
1288 		seq_printf(s, " duty: %llu ns", state.duty_cycle);
1289 		seq_printf(s, " polarity: %s",
1290 			   state.polarity ? "inverse" : "normal");
1291 
1292 		seq_puts(s, "\n");
1293 	}
1294 }
1295 
1296 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1297 {
1298 	mutex_lock(&pwm_lock);
1299 	s->private = "";
1300 
1301 	return seq_list_start(&pwm_chips, *pos);
1302 }
1303 
1304 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1305 {
1306 	s->private = "\n";
1307 
1308 	return seq_list_next(v, &pwm_chips, pos);
1309 }
1310 
1311 static void pwm_seq_stop(struct seq_file *s, void *v)
1312 {
1313 	mutex_unlock(&pwm_lock);
1314 }
1315 
1316 static int pwm_seq_show(struct seq_file *s, void *v)
1317 {
1318 	struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1319 
1320 	seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1321 		   chip->dev->bus ? chip->dev->bus->name : "no-bus",
1322 		   dev_name(chip->dev), chip->npwm,
1323 		   (chip->npwm != 1) ? "s" : "");
1324 
1325 	pwm_dbg_show(chip, s);
1326 
1327 	return 0;
1328 }
1329 
1330 static const struct seq_operations pwm_seq_ops = {
1331 	.start = pwm_seq_start,
1332 	.next = pwm_seq_next,
1333 	.stop = pwm_seq_stop,
1334 	.show = pwm_seq_show,
1335 };
1336 
1337 static int pwm_seq_open(struct inode *inode, struct file *file)
1338 {
1339 	return seq_open(file, &pwm_seq_ops);
1340 }
1341 
1342 static const struct file_operations pwm_debugfs_ops = {
1343 	.owner = THIS_MODULE,
1344 	.open = pwm_seq_open,
1345 	.read = seq_read,
1346 	.llseek = seq_lseek,
1347 	.release = seq_release,
1348 };
1349 
1350 static int __init pwm_debugfs_init(void)
1351 {
1352 	debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1353 			    &pwm_debugfs_ops);
1354 
1355 	return 0;
1356 }
1357 subsys_initcall(pwm_debugfs_init);
1358 #endif /* CONFIG_DEBUG_FS */
1359