1/*
2 * Generic pwmlib implementation
3 *
4 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
5 * Copyright (C) 2011-2012 Avionic Design GmbH
6 *
7 *  This program is free software; you can redistribute it and/or modify
8 *  it under the terms of the GNU General Public License as published by
9 *  the Free Software Foundation; either version 2, or (at your option)
10 *  any later version.
11 *
12 *  This program is distributed in the hope that it will be useful,
13 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
14 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 *  GNU General Public License for more details.
16 *
17 *  You should have received a copy of the GNU General Public License
18 *  along with this program; see the file COPYING.  If not, write to
19 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22#include <linux/module.h>
23#include <linux/pwm.h>
24#include <linux/radix-tree.h>
25#include <linux/list.h>
26#include <linux/mutex.h>
27#include <linux/err.h>
28#include <linux/slab.h>
29#include <linux/device.h>
30#include <linux/debugfs.h>
31#include <linux/seq_file.h>
32
33#include <dt-bindings/pwm/pwm.h>
34
35#define MAX_PWMS 1024
36
37static DEFINE_MUTEX(pwm_lookup_lock);
38static LIST_HEAD(pwm_lookup_list);
39static DEFINE_MUTEX(pwm_lock);
40static LIST_HEAD(pwm_chips);
41static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
42static RADIX_TREE(pwm_tree, GFP_KERNEL);
43
44static struct pwm_device *pwm_to_device(unsigned int pwm)
45{
46	return radix_tree_lookup(&pwm_tree, pwm);
47}
48
49static int alloc_pwms(int pwm, unsigned int count)
50{
51	unsigned int from = 0;
52	unsigned int start;
53
54	if (pwm >= MAX_PWMS)
55		return -EINVAL;
56
57	if (pwm >= 0)
58		from = pwm;
59
60	start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
61					   count, 0);
62
63	if (pwm >= 0 && start != pwm)
64		return -EEXIST;
65
66	if (start + count > MAX_PWMS)
67		return -ENOSPC;
68
69	return start;
70}
71
72static void free_pwms(struct pwm_chip *chip)
73{
74	unsigned int i;
75
76	for (i = 0; i < chip->npwm; i++) {
77		struct pwm_device *pwm = &chip->pwms[i];
78		radix_tree_delete(&pwm_tree, pwm->pwm);
79	}
80
81	bitmap_clear(allocated_pwms, chip->base, chip->npwm);
82
83	kfree(chip->pwms);
84	chip->pwms = NULL;
85}
86
87static struct pwm_chip *pwmchip_find_by_name(const char *name)
88{
89	struct pwm_chip *chip;
90
91	if (!name)
92		return NULL;
93
94	mutex_lock(&pwm_lock);
95
96	list_for_each_entry(chip, &pwm_chips, list) {
97		const char *chip_name = dev_name(chip->dev);
98
99		if (chip_name && strcmp(chip_name, name) == 0) {
100			mutex_unlock(&pwm_lock);
101			return chip;
102		}
103	}
104
105	mutex_unlock(&pwm_lock);
106
107	return NULL;
108}
109
110static int pwm_device_request(struct pwm_device *pwm, const char *label)
111{
112	int err;
113
114	if (test_bit(PWMF_REQUESTED, &pwm->flags))
115		return -EBUSY;
116
117	if (!try_module_get(pwm->chip->ops->owner))
118		return -ENODEV;
119
120	if (pwm->chip->ops->request) {
121		err = pwm->chip->ops->request(pwm->chip, pwm);
122		if (err) {
123			module_put(pwm->chip->ops->owner);
124			return err;
125		}
126	}
127
128	set_bit(PWMF_REQUESTED, &pwm->flags);
129	pwm->label = label;
130
131	return 0;
132}
133
134struct pwm_device *
135of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
136{
137	struct pwm_device *pwm;
138
139	if (pc->of_pwm_n_cells < 3)
140		return ERR_PTR(-EINVAL);
141
142	if (args->args[0] >= pc->npwm)
143		return ERR_PTR(-EINVAL);
144
145	pwm = pwm_request_from_chip(pc, args->args[0], NULL);
146	if (IS_ERR(pwm))
147		return pwm;
148
149	pwm_set_period(pwm, args->args[1]);
150
151	if (args->args[2] & PWM_POLARITY_INVERTED)
152		pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
153	else
154		pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
155
156	return pwm;
157}
158EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
159
160static struct pwm_device *
161of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
162{
163	struct pwm_device *pwm;
164
165	if (pc->of_pwm_n_cells < 2)
166		return ERR_PTR(-EINVAL);
167
168	if (args->args[0] >= pc->npwm)
169		return ERR_PTR(-EINVAL);
170
171	pwm = pwm_request_from_chip(pc, args->args[0], NULL);
172	if (IS_ERR(pwm))
173		return pwm;
174
175	pwm_set_period(pwm, args->args[1]);
176
177	return pwm;
178}
179
180static void of_pwmchip_add(struct pwm_chip *chip)
181{
182	if (!chip->dev || !chip->dev->of_node)
183		return;
184
185	if (!chip->of_xlate) {
186		chip->of_xlate = of_pwm_simple_xlate;
187		chip->of_pwm_n_cells = 2;
188	}
189
190	of_node_get(chip->dev->of_node);
191}
192
193static void of_pwmchip_remove(struct pwm_chip *chip)
194{
195	if (chip->dev)
196		of_node_put(chip->dev->of_node);
197}
198
199/**
200 * pwm_set_chip_data() - set private chip data for a PWM
201 * @pwm: PWM device
202 * @data: pointer to chip-specific data
203 */
204int pwm_set_chip_data(struct pwm_device *pwm, void *data)
205{
206	if (!pwm)
207		return -EINVAL;
208
209	pwm->chip_data = data;
210
211	return 0;
212}
213EXPORT_SYMBOL_GPL(pwm_set_chip_data);
214
215/**
216 * pwm_get_chip_data() - get private chip data for a PWM
217 * @pwm: PWM device
218 */
219void *pwm_get_chip_data(struct pwm_device *pwm)
220{
221	return pwm ? pwm->chip_data : NULL;
222}
223EXPORT_SYMBOL_GPL(pwm_get_chip_data);
224
225/**
226 * pwmchip_add() - register a new PWM chip
227 * @chip: the PWM chip to add
228 *
229 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
230 * will be used.
231 */
232int pwmchip_add(struct pwm_chip *chip)
233{
234	struct pwm_device *pwm;
235	unsigned int i;
236	int ret;
237
238	if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
239	    !chip->ops->enable || !chip->ops->disable || !chip->npwm)
240		return -EINVAL;
241
242	mutex_lock(&pwm_lock);
243
244	ret = alloc_pwms(chip->base, chip->npwm);
245	if (ret < 0)
246		goto out;
247
248	chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
249	if (!chip->pwms) {
250		ret = -ENOMEM;
251		goto out;
252	}
253
254	chip->base = ret;
255
256	for (i = 0; i < chip->npwm; i++) {
257		pwm = &chip->pwms[i];
258
259		pwm->chip = chip;
260		pwm->pwm = chip->base + i;
261		pwm->hwpwm = i;
262
263		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
264	}
265
266	bitmap_set(allocated_pwms, chip->base, chip->npwm);
267
268	INIT_LIST_HEAD(&chip->list);
269	list_add(&chip->list, &pwm_chips);
270
271	ret = 0;
272
273	if (IS_ENABLED(CONFIG_OF))
274		of_pwmchip_add(chip);
275
276	pwmchip_sysfs_export(chip);
277
278out:
279	mutex_unlock(&pwm_lock);
280	return ret;
281}
282EXPORT_SYMBOL_GPL(pwmchip_add);
283
284/**
285 * pwmchip_remove() - remove a PWM chip
286 * @chip: the PWM chip to remove
287 *
288 * Removes a PWM chip. This function may return busy if the PWM chip provides
289 * a PWM device that is still requested.
290 */
291int pwmchip_remove(struct pwm_chip *chip)
292{
293	unsigned int i;
294	int ret = 0;
295
296	mutex_lock(&pwm_lock);
297
298	for (i = 0; i < chip->npwm; i++) {
299		struct pwm_device *pwm = &chip->pwms[i];
300
301		if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
302			ret = -EBUSY;
303			goto out;
304		}
305	}
306
307	list_del_init(&chip->list);
308
309	if (IS_ENABLED(CONFIG_OF))
310		of_pwmchip_remove(chip);
311
312	free_pwms(chip);
313
314	pwmchip_sysfs_unexport(chip);
315
316out:
317	mutex_unlock(&pwm_lock);
318	return ret;
319}
320EXPORT_SYMBOL_GPL(pwmchip_remove);
321
322/**
323 * pwm_request() - request a PWM device
324 * @pwm_id: global PWM device index
325 * @label: PWM device label
326 *
327 * This function is deprecated, use pwm_get() instead.
328 */
329struct pwm_device *pwm_request(int pwm, const char *label)
330{
331	struct pwm_device *dev;
332	int err;
333
334	if (pwm < 0 || pwm >= MAX_PWMS)
335		return ERR_PTR(-EINVAL);
336
337	mutex_lock(&pwm_lock);
338
339	dev = pwm_to_device(pwm);
340	if (!dev) {
341		dev = ERR_PTR(-EPROBE_DEFER);
342		goto out;
343	}
344
345	err = pwm_device_request(dev, label);
346	if (err < 0)
347		dev = ERR_PTR(err);
348
349out:
350	mutex_unlock(&pwm_lock);
351
352	return dev;
353}
354EXPORT_SYMBOL_GPL(pwm_request);
355
356/**
357 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
358 * @chip: PWM chip
359 * @index: per-chip index of the PWM to request
360 * @label: a literal description string of this PWM
361 *
362 * Returns the PWM at the given index of the given PWM chip. A negative error
363 * code is returned if the index is not valid for the specified PWM chip or
364 * if the PWM device cannot be requested.
365 */
366struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
367					 unsigned int index,
368					 const char *label)
369{
370	struct pwm_device *pwm;
371	int err;
372
373	if (!chip || index >= chip->npwm)
374		return ERR_PTR(-EINVAL);
375
376	mutex_lock(&pwm_lock);
377	pwm = &chip->pwms[index];
378
379	err = pwm_device_request(pwm, label);
380	if (err < 0)
381		pwm = ERR_PTR(err);
382
383	mutex_unlock(&pwm_lock);
384	return pwm;
385}
386EXPORT_SYMBOL_GPL(pwm_request_from_chip);
387
388/**
389 * pwm_free() - free a PWM device
390 * @pwm: PWM device
391 *
392 * This function is deprecated, use pwm_put() instead.
393 */
394void pwm_free(struct pwm_device *pwm)
395{
396	pwm_put(pwm);
397}
398EXPORT_SYMBOL_GPL(pwm_free);
399
400/**
401 * pwm_config() - change a PWM device configuration
402 * @pwm: PWM device
403 * @duty_ns: "on" time (in nanoseconds)
404 * @period_ns: duration (in nanoseconds) of one cycle
405 */
406int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
407{
408	int err;
409
410	if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
411		return -EINVAL;
412
413	err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
414	if (err)
415		return err;
416
417	pwm->duty_cycle = duty_ns;
418	pwm->period = period_ns;
419
420	return 0;
421}
422EXPORT_SYMBOL_GPL(pwm_config);
423
424/**
425 * pwm_set_polarity() - configure the polarity of a PWM signal
426 * @pwm: PWM device
427 * @polarity: new polarity of the PWM signal
428 *
429 * Note that the polarity cannot be configured while the PWM device is enabled
430 */
431int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
432{
433	int err;
434
435	if (!pwm || !pwm->chip->ops)
436		return -EINVAL;
437
438	if (!pwm->chip->ops->set_polarity)
439		return -ENOSYS;
440
441	if (test_bit(PWMF_ENABLED, &pwm->flags))
442		return -EBUSY;
443
444	err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
445	if (err)
446		return err;
447
448	pwm->polarity = polarity;
449
450	return 0;
451}
452EXPORT_SYMBOL_GPL(pwm_set_polarity);
453
454/**
455 * pwm_enable() - start a PWM output toggling
456 * @pwm: PWM device
457 */
458int pwm_enable(struct pwm_device *pwm)
459{
460	if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
461		return pwm->chip->ops->enable(pwm->chip, pwm);
462
463	return pwm ? 0 : -EINVAL;
464}
465EXPORT_SYMBOL_GPL(pwm_enable);
466
467/**
468 * pwm_disable() - stop a PWM output toggling
469 * @pwm: PWM device
470 */
471void pwm_disable(struct pwm_device *pwm)
472{
473	if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
474		pwm->chip->ops->disable(pwm->chip, pwm);
475}
476EXPORT_SYMBOL_GPL(pwm_disable);
477
478static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
479{
480	struct pwm_chip *chip;
481
482	mutex_lock(&pwm_lock);
483
484	list_for_each_entry(chip, &pwm_chips, list)
485		if (chip->dev && chip->dev->of_node == np) {
486			mutex_unlock(&pwm_lock);
487			return chip;
488		}
489
490	mutex_unlock(&pwm_lock);
491
492	return ERR_PTR(-EPROBE_DEFER);
493}
494
495/**
496 * of_pwm_get() - request a PWM via the PWM framework
497 * @np: device node to get the PWM from
498 * @con_id: consumer name
499 *
500 * Returns the PWM device parsed from the phandle and index specified in the
501 * "pwms" property of a device tree node or a negative error-code on failure.
502 * Values parsed from the device tree are stored in the returned PWM device
503 * object.
504 *
505 * If con_id is NULL, the first PWM device listed in the "pwms" property will
506 * be requested. Otherwise the "pwm-names" property is used to do a reverse
507 * lookup of the PWM index. This also means that the "pwm-names" property
508 * becomes mandatory for devices that look up the PWM device via the con_id
509 * parameter.
510 */
511struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
512{
513	struct pwm_device *pwm = NULL;
514	struct of_phandle_args args;
515	struct pwm_chip *pc;
516	int index = 0;
517	int err;
518
519	if (con_id) {
520		index = of_property_match_string(np, "pwm-names", con_id);
521		if (index < 0)
522			return ERR_PTR(index);
523	}
524
525	err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
526					 &args);
527	if (err) {
528		pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
529		return ERR_PTR(err);
530	}
531
532	pc = of_node_to_pwmchip(args.np);
533	if (IS_ERR(pc)) {
534		pr_debug("%s(): PWM chip not found\n", __func__);
535		pwm = ERR_CAST(pc);
536		goto put;
537	}
538
539	if (args.args_count != pc->of_pwm_n_cells) {
540		pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
541			 args.np->full_name);
542		pwm = ERR_PTR(-EINVAL);
543		goto put;
544	}
545
546	pwm = pc->of_xlate(pc, &args);
547	if (IS_ERR(pwm))
548		goto put;
549
550	/*
551	 * If a consumer name was not given, try to look it up from the
552	 * "pwm-names" property if it exists. Otherwise use the name of
553	 * the user device node.
554	 */
555	if (!con_id) {
556		err = of_property_read_string_index(np, "pwm-names", index,
557						    &con_id);
558		if (err < 0)
559			con_id = np->name;
560	}
561
562	pwm->label = con_id;
563
564put:
565	of_node_put(args.np);
566
567	return pwm;
568}
569EXPORT_SYMBOL_GPL(of_pwm_get);
570
571/**
572 * pwm_add_table() - register PWM device consumers
573 * @table: array of consumers to register
574 * @num: number of consumers in table
575 */
576void pwm_add_table(struct pwm_lookup *table, size_t num)
577{
578	mutex_lock(&pwm_lookup_lock);
579
580	while (num--) {
581		list_add_tail(&table->list, &pwm_lookup_list);
582		table++;
583	}
584
585	mutex_unlock(&pwm_lookup_lock);
586}
587
588/**
589 * pwm_get() - look up and request a PWM device
590 * @dev: device for PWM consumer
591 * @con_id: consumer name
592 *
593 * Lookup is first attempted using DT. If the device was not instantiated from
594 * a device tree, a PWM chip and a relative index is looked up via a table
595 * supplied by board setup code (see pwm_add_table()).
596 *
597 * Once a PWM chip has been found the specified PWM device will be requested
598 * and is ready to be used.
599 */
600struct pwm_device *pwm_get(struct device *dev, const char *con_id)
601{
602	struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
603	const char *dev_id = dev ? dev_name(dev) : NULL;
604	struct pwm_chip *chip = NULL;
605	unsigned int best = 0;
606	struct pwm_lookup *p, *chosen = NULL;
607	unsigned int match;
608
609	/* look up via DT first */
610	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
611		return of_pwm_get(dev->of_node, con_id);
612
613	/*
614	 * We look up the provider in the static table typically provided by
615	 * board setup code. We first try to lookup the consumer device by
616	 * name. If the consumer device was passed in as NULL or if no match
617	 * was found, we try to find the consumer by directly looking it up
618	 * by name.
619	 *
620	 * If a match is found, the provider PWM chip is looked up by name
621	 * and a PWM device is requested using the PWM device per-chip index.
622	 *
623	 * The lookup algorithm was shamelessly taken from the clock
624	 * framework:
625	 *
626	 * We do slightly fuzzy matching here:
627	 *  An entry with a NULL ID is assumed to be a wildcard.
628	 *  If an entry has a device ID, it must match
629	 *  If an entry has a connection ID, it must match
630	 * Then we take the most specific entry - with the following order
631	 * of precedence: dev+con > dev only > con only.
632	 */
633	mutex_lock(&pwm_lookup_lock);
634
635	list_for_each_entry(p, &pwm_lookup_list, list) {
636		match = 0;
637
638		if (p->dev_id) {
639			if (!dev_id || strcmp(p->dev_id, dev_id))
640				continue;
641
642			match += 2;
643		}
644
645		if (p->con_id) {
646			if (!con_id || strcmp(p->con_id, con_id))
647				continue;
648
649			match += 1;
650		}
651
652		if (match > best) {
653			chosen = p;
654
655			if (match != 3)
656				best = match;
657			else
658				break;
659		}
660	}
661
662	if (!chosen)
663		goto out;
664
665	chip = pwmchip_find_by_name(chosen->provider);
666	if (!chip)
667		goto out;
668
669	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
670	if (IS_ERR(pwm))
671		goto out;
672
673	pwm_set_period(pwm, chosen->period);
674	pwm_set_polarity(pwm, chosen->polarity);
675
676out:
677	mutex_unlock(&pwm_lookup_lock);
678	return pwm;
679}
680EXPORT_SYMBOL_GPL(pwm_get);
681
682/**
683 * pwm_put() - release a PWM device
684 * @pwm: PWM device
685 */
686void pwm_put(struct pwm_device *pwm)
687{
688	if (!pwm)
689		return;
690
691	mutex_lock(&pwm_lock);
692
693	if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
694		pr_warn("PWM device already freed\n");
695		goto out;
696	}
697
698	if (pwm->chip->ops->free)
699		pwm->chip->ops->free(pwm->chip, pwm);
700
701	pwm->label = NULL;
702
703	module_put(pwm->chip->ops->owner);
704out:
705	mutex_unlock(&pwm_lock);
706}
707EXPORT_SYMBOL_GPL(pwm_put);
708
709static void devm_pwm_release(struct device *dev, void *res)
710{
711	pwm_put(*(struct pwm_device **)res);
712}
713
714/**
715 * devm_pwm_get() - resource managed pwm_get()
716 * @dev: device for PWM consumer
717 * @con_id: consumer name
718 *
719 * This function performs like pwm_get() but the acquired PWM device will
720 * automatically be released on driver detach.
721 */
722struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
723{
724	struct pwm_device **ptr, *pwm;
725
726	ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
727	if (!ptr)
728		return ERR_PTR(-ENOMEM);
729
730	pwm = pwm_get(dev, con_id);
731	if (!IS_ERR(pwm)) {
732		*ptr = pwm;
733		devres_add(dev, ptr);
734	} else {
735		devres_free(ptr);
736	}
737
738	return pwm;
739}
740EXPORT_SYMBOL_GPL(devm_pwm_get);
741
742/**
743 * devm_of_pwm_get() - resource managed of_pwm_get()
744 * @dev: device for PWM consumer
745 * @np: device node to get the PWM from
746 * @con_id: consumer name
747 *
748 * This function performs like of_pwm_get() but the acquired PWM device will
749 * automatically be released on driver detach.
750 */
751struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
752				   const char *con_id)
753{
754	struct pwm_device **ptr, *pwm;
755
756	ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
757	if (!ptr)
758		return ERR_PTR(-ENOMEM);
759
760	pwm = of_pwm_get(np, con_id);
761	if (!IS_ERR(pwm)) {
762		*ptr = pwm;
763		devres_add(dev, ptr);
764	} else {
765		devres_free(ptr);
766	}
767
768	return pwm;
769}
770EXPORT_SYMBOL_GPL(devm_of_pwm_get);
771
772static int devm_pwm_match(struct device *dev, void *res, void *data)
773{
774	struct pwm_device **p = res;
775
776	if (WARN_ON(!p || !*p))
777		return 0;
778
779	return *p == data;
780}
781
782/**
783 * devm_pwm_put() - resource managed pwm_put()
784 * @dev: device for PWM consumer
785 * @pwm: PWM device
786 *
787 * Release a PWM previously allocated using devm_pwm_get(). Calling this
788 * function is usually not needed because devm-allocated resources are
789 * automatically released on driver detach.
790 */
791void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
792{
793	WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
794}
795EXPORT_SYMBOL_GPL(devm_pwm_put);
796
797/**
798  * pwm_can_sleep() - report whether PWM access will sleep
799  * @pwm: PWM device
800  *
801  * It returns true if accessing the PWM can sleep, false otherwise.
802  */
803bool pwm_can_sleep(struct pwm_device *pwm)
804{
805	return pwm->chip->can_sleep;
806}
807EXPORT_SYMBOL_GPL(pwm_can_sleep);
808
809#ifdef CONFIG_DEBUG_FS
810static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
811{
812	unsigned int i;
813
814	for (i = 0; i < chip->npwm; i++) {
815		struct pwm_device *pwm = &chip->pwms[i];
816
817		seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
818
819		if (test_bit(PWMF_REQUESTED, &pwm->flags))
820			seq_puts(s, " requested");
821
822		if (test_bit(PWMF_ENABLED, &pwm->flags))
823			seq_puts(s, " enabled");
824
825		seq_puts(s, "\n");
826	}
827}
828
829static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
830{
831	mutex_lock(&pwm_lock);
832	s->private = "";
833
834	return seq_list_start(&pwm_chips, *pos);
835}
836
837static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
838{
839	s->private = "\n";
840
841	return seq_list_next(v, &pwm_chips, pos);
842}
843
844static void pwm_seq_stop(struct seq_file *s, void *v)
845{
846	mutex_unlock(&pwm_lock);
847}
848
849static int pwm_seq_show(struct seq_file *s, void *v)
850{
851	struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
852
853	seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
854		   chip->dev->bus ? chip->dev->bus->name : "no-bus",
855		   dev_name(chip->dev), chip->npwm,
856		   (chip->npwm != 1) ? "s" : "");
857
858	if (chip->ops->dbg_show)
859		chip->ops->dbg_show(chip, s);
860	else
861		pwm_dbg_show(chip, s);
862
863	return 0;
864}
865
866static const struct seq_operations pwm_seq_ops = {
867	.start = pwm_seq_start,
868	.next = pwm_seq_next,
869	.stop = pwm_seq_stop,
870	.show = pwm_seq_show,
871};
872
873static int pwm_seq_open(struct inode *inode, struct file *file)
874{
875	return seq_open(file, &pwm_seq_ops);
876}
877
878static const struct file_operations pwm_debugfs_ops = {
879	.owner = THIS_MODULE,
880	.open = pwm_seq_open,
881	.read = seq_read,
882	.llseek = seq_lseek,
883	.release = seq_release,
884};
885
886static int __init pwm_debugfs_init(void)
887{
888	debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
889			    &pwm_debugfs_ops);
890
891	return 0;
892}
893
894subsys_initcall(pwm_debugfs_init);
895#endif /* CONFIG_DEBUG_FS */
896