source: src/linux/universal/linux-3.18/drivers/pwm/core.c @ 31869

Last change on this file since 31869 was 31869, checked in by brainslayer, 6 weeks ago

update

File size: 19.3 KB
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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 && chip->dev->of_node)
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        pwmchip_sysfs_unexport_children(chip);
297
298        mutex_lock(&pwm_lock);
299
300        for (i = 0; i < chip->npwm; i++) {
301                struct pwm_device *pwm = &chip->pwms[i];
302
303                if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
304                        ret = -EBUSY;
305                        goto out;
306                }
307        }
308
309        list_del_init(&chip->list);
310
311        if (IS_ENABLED(CONFIG_OF))
312                of_pwmchip_remove(chip);
313
314        free_pwms(chip);
315
316        pwmchip_sysfs_unexport(chip);
317
318out:
319        mutex_unlock(&pwm_lock);
320        return ret;
321}
322EXPORT_SYMBOL_GPL(pwmchip_remove);
323
324/**
325 * pwm_request() - request a PWM device
326 * @pwm_id: global PWM device index
327 * @label: PWM device label
328 *
329 * This function is deprecated, use pwm_get() instead.
330 */
331struct pwm_device *pwm_request(int pwm, const char *label)
332{
333        struct pwm_device *dev;
334        int err;
335
336        if (pwm < 0 || pwm >= MAX_PWMS)
337                return ERR_PTR(-EINVAL);
338
339        mutex_lock(&pwm_lock);
340
341        dev = pwm_to_device(pwm);
342        if (!dev) {
343                dev = ERR_PTR(-EPROBE_DEFER);
344                goto out;
345        }
346
347        err = pwm_device_request(dev, label);
348        if (err < 0)
349                dev = ERR_PTR(err);
350
351out:
352        mutex_unlock(&pwm_lock);
353
354        return dev;
355}
356EXPORT_SYMBOL_GPL(pwm_request);
357
358/**
359 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
360 * @chip: PWM chip
361 * @index: per-chip index of the PWM to request
362 * @label: a literal description string of this PWM
363 *
364 * Returns the PWM at the given index of the given PWM chip. A negative error
365 * code is returned if the index is not valid for the specified PWM chip or
366 * if the PWM device cannot be requested.
367 */
368struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
369                                         unsigned int index,
370                                         const char *label)
371{
372        struct pwm_device *pwm;
373        int err;
374
375        if (!chip || index >= chip->npwm)
376                return ERR_PTR(-EINVAL);
377
378        mutex_lock(&pwm_lock);
379        pwm = &chip->pwms[index];
380
381        err = pwm_device_request(pwm, label);
382        if (err < 0)
383                pwm = ERR_PTR(err);
384
385        mutex_unlock(&pwm_lock);
386        return pwm;
387}
388EXPORT_SYMBOL_GPL(pwm_request_from_chip);
389
390/**
391 * pwm_free() - free a PWM device
392 * @pwm: PWM device
393 *
394 * This function is deprecated, use pwm_put() instead.
395 */
396void pwm_free(struct pwm_device *pwm)
397{
398        pwm_put(pwm);
399}
400EXPORT_SYMBOL_GPL(pwm_free);
401
402/**
403 * pwm_config() - change a PWM device configuration
404 * @pwm: PWM device
405 * @duty_ns: "on" time (in nanoseconds)
406 * @period_ns: duration (in nanoseconds) of one cycle
407 */
408int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
409{
410        int err;
411
412        if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
413                return -EINVAL;
414
415        err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
416        if (err)
417                return err;
418
419        pwm->duty_cycle = duty_ns;
420        pwm->period = period_ns;
421
422        return 0;
423}
424EXPORT_SYMBOL_GPL(pwm_config);
425
426/**
427 * pwm_set_polarity() - configure the polarity of a PWM signal
428 * @pwm: PWM device
429 * @polarity: new polarity of the PWM signal
430 *
431 * Note that the polarity cannot be configured while the PWM device is enabled
432 */
433int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
434{
435        int err;
436
437        if (!pwm || !pwm->chip->ops)
438                return -EINVAL;
439
440        if (!pwm->chip->ops->set_polarity)
441                return -ENOSYS;
442
443        if (test_bit(PWMF_ENABLED, &pwm->flags))
444                return -EBUSY;
445
446        err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
447        if (err)
448                return err;
449
450        pwm->polarity = polarity;
451
452        return 0;
453}
454EXPORT_SYMBOL_GPL(pwm_set_polarity);
455
456/**
457 * pwm_enable() - start a PWM output toggling
458 * @pwm: PWM device
459 */
460int pwm_enable(struct pwm_device *pwm)
461{
462        if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
463                return pwm->chip->ops->enable(pwm->chip, pwm);
464
465        return pwm ? 0 : -EINVAL;
466}
467EXPORT_SYMBOL_GPL(pwm_enable);
468
469/**
470 * pwm_disable() - stop a PWM output toggling
471 * @pwm: PWM device
472 */
473void pwm_disable(struct pwm_device *pwm)
474{
475        if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
476                pwm->chip->ops->disable(pwm->chip, pwm);
477}
478EXPORT_SYMBOL_GPL(pwm_disable);
479
480static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
481{
482        struct pwm_chip *chip;
483
484        mutex_lock(&pwm_lock);
485
486        list_for_each_entry(chip, &pwm_chips, list)
487                if (chip->dev && chip->dev->of_node == np) {
488                        mutex_unlock(&pwm_lock);
489                        return chip;
490                }
491
492        mutex_unlock(&pwm_lock);
493
494        return ERR_PTR(-EPROBE_DEFER);
495}
496
497/**
498 * of_pwm_get() - request a PWM via the PWM framework
499 * @np: device node to get the PWM from
500 * @con_id: consumer name
501 *
502 * Returns the PWM device parsed from the phandle and index specified in the
503 * "pwms" property of a device tree node or a negative error-code on failure.
504 * Values parsed from the device tree are stored in the returned PWM device
505 * object.
506 *
507 * If con_id is NULL, the first PWM device listed in the "pwms" property will
508 * be requested. Otherwise the "pwm-names" property is used to do a reverse
509 * lookup of the PWM index. This also means that the "pwm-names" property
510 * becomes mandatory for devices that look up the PWM device via the con_id
511 * parameter.
512 */
513struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
514{
515        struct pwm_device *pwm = NULL;
516        struct of_phandle_args args;
517        struct pwm_chip *pc;
518        int index = 0;
519        int err;
520
521        if (con_id) {
522                index = of_property_match_string(np, "pwm-names", con_id);
523                if (index < 0)
524                        return ERR_PTR(index);
525        }
526
527        err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
528                                         &args);
529        if (err) {
530                pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
531                return ERR_PTR(err);
532        }
533
534        pc = of_node_to_pwmchip(args.np);
535        if (IS_ERR(pc)) {
536                pr_debug("%s(): PWM chip not found\n", __func__);
537                pwm = ERR_CAST(pc);
538                goto put;
539        }
540
541        if (args.args_count != pc->of_pwm_n_cells) {
542                pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
543                         args.np->full_name);
544                pwm = ERR_PTR(-EINVAL);
545                goto put;
546        }
547
548        pwm = pc->of_xlate(pc, &args);
549        if (IS_ERR(pwm))
550                goto put;
551
552        /*
553         * If a consumer name was not given, try to look it up from the
554         * "pwm-names" property if it exists. Otherwise use the name of
555         * the user device node.
556         */
557        if (!con_id) {
558                err = of_property_read_string_index(np, "pwm-names", index,
559                                                    &con_id);
560                if (err < 0)
561                        con_id = np->name;
562        }
563
564        pwm->label = con_id;
565
566put:
567        of_node_put(args.np);
568
569        return pwm;
570}
571EXPORT_SYMBOL_GPL(of_pwm_get);
572
573/**
574 * pwm_add_table() - register PWM device consumers
575 * @table: array of consumers to register
576 * @num: number of consumers in table
577 */
578void __init pwm_add_table(struct pwm_lookup *table, size_t num)
579{
580        mutex_lock(&pwm_lookup_lock);
581
582        while (num--) {
583                list_add_tail(&table->list, &pwm_lookup_list);
584                table++;
585        }
586
587        mutex_unlock(&pwm_lookup_lock);
588}
589
590/**
591 * pwm_get() - look up and request a PWM device
592 * @dev: device for PWM consumer
593 * @con_id: consumer name
594 *
595 * Lookup is first attempted using DT. If the device was not instantiated from
596 * a device tree, a PWM chip and a relative index is looked up via a table
597 * supplied by board setup code (see pwm_add_table()).
598 *
599 * Once a PWM chip has been found the specified PWM device will be requested
600 * and is ready to be used.
601 */
602struct pwm_device *pwm_get(struct device *dev, const char *con_id)
603{
604        struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
605        const char *dev_id = dev ? dev_name(dev) : NULL;
606        struct pwm_chip *chip = NULL;
607        unsigned int best = 0;
608        struct pwm_lookup *p, *chosen = NULL;
609        unsigned int match;
610
611        /* look up via DT first */
612        if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
613                return of_pwm_get(dev->of_node, con_id);
614
615        /*
616         * We look up the provider in the static table typically provided by
617         * board setup code. We first try to lookup the consumer device by
618         * name. If the consumer device was passed in as NULL or if no match
619         * was found, we try to find the consumer by directly looking it up
620         * by name.
621         *
622         * If a match is found, the provider PWM chip is looked up by name
623         * and a PWM device is requested using the PWM device per-chip index.
624         *
625         * The lookup algorithm was shamelessly taken from the clock
626         * framework:
627         *
628         * We do slightly fuzzy matching here:
629         *  An entry with a NULL ID is assumed to be a wildcard.
630         *  If an entry has a device ID, it must match
631         *  If an entry has a connection ID, it must match
632         * Then we take the most specific entry - with the following order
633         * of precedence: dev+con > dev only > con only.
634         */
635        mutex_lock(&pwm_lookup_lock);
636
637        list_for_each_entry(p, &pwm_lookup_list, list) {
638                match = 0;
639
640                if (p->dev_id) {
641                        if (!dev_id || strcmp(p->dev_id, dev_id))
642                                continue;
643
644                        match += 2;
645                }
646
647                if (p->con_id) {
648                        if (!con_id || strcmp(p->con_id, con_id))
649                                continue;
650
651                        match += 1;
652                }
653
654                if (match > best) {
655                        chosen = p;
656
657                        if (match != 3)
658                                best = match;
659                        else
660                                break;
661                }
662        }
663
664        if (!chosen)
665                goto out;
666
667        chip = pwmchip_find_by_name(chosen->provider);
668        if (!chip)
669                goto out;
670
671        pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
672        if (IS_ERR(pwm))
673                goto out;
674
675        pwm_set_period(pwm, chosen->period);
676        pwm_set_polarity(pwm, chosen->polarity);
677
678out:
679        mutex_unlock(&pwm_lookup_lock);
680        return pwm;
681}
682EXPORT_SYMBOL_GPL(pwm_get);
683
684/**
685 * pwm_put() - release a PWM device
686 * @pwm: PWM device
687 */
688void pwm_put(struct pwm_device *pwm)
689{
690        if (!pwm)
691                return;
692
693        mutex_lock(&pwm_lock);
694
695        if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
696                pr_warn("PWM device already freed\n");
697                goto out;
698        }
699
700        if (pwm->chip->ops->free)
701                pwm->chip->ops->free(pwm->chip, pwm);
702
703        pwm->label = NULL;
704
705        module_put(pwm->chip->ops->owner);
706out:
707        mutex_unlock(&pwm_lock);
708}
709EXPORT_SYMBOL_GPL(pwm_put);
710
711static void devm_pwm_release(struct device *dev, void *res)
712{
713        pwm_put(*(struct pwm_device **)res);
714}
715
716/**
717 * devm_pwm_get() - resource managed pwm_get()
718 * @dev: device for PWM consumer
719 * @con_id: consumer name
720 *
721 * This function performs like pwm_get() but the acquired PWM device will
722 * automatically be released on driver detach.
723 */
724struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
725{
726        struct pwm_device **ptr, *pwm;
727
728        ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
729        if (!ptr)
730                return ERR_PTR(-ENOMEM);
731
732        pwm = pwm_get(dev, con_id);
733        if (!IS_ERR(pwm)) {
734                *ptr = pwm;
735                devres_add(dev, ptr);
736        } else {
737                devres_free(ptr);
738        }
739
740        return pwm;
741}
742EXPORT_SYMBOL_GPL(devm_pwm_get);
743
744/**
745 * devm_of_pwm_get() - resource managed of_pwm_get()
746 * @dev: device for PWM consumer
747 * @np: device node to get the PWM from
748 * @con_id: consumer name
749 *
750 * This function performs like of_pwm_get() but the acquired PWM device will
751 * automatically be released on driver detach.
752 */
753struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
754                                   const char *con_id)
755{
756        struct pwm_device **ptr, *pwm;
757
758        ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
759        if (!ptr)
760                return ERR_PTR(-ENOMEM);
761
762        pwm = of_pwm_get(np, con_id);
763        if (!IS_ERR(pwm)) {
764                *ptr = pwm;
765                devres_add(dev, ptr);
766        } else {
767                devres_free(ptr);
768        }
769
770        return pwm;
771}
772EXPORT_SYMBOL_GPL(devm_of_pwm_get);
773
774static int devm_pwm_match(struct device *dev, void *res, void *data)
775{
776        struct pwm_device **p = res;
777
778        if (WARN_ON(!p || !*p))
779                return 0;
780
781        return *p == data;
782}
783
784/**
785 * devm_pwm_put() - resource managed pwm_put()
786 * @dev: device for PWM consumer
787 * @pwm: PWM device
788 *
789 * Release a PWM previously allocated using devm_pwm_get(). Calling this
790 * function is usually not needed because devm-allocated resources are
791 * automatically released on driver detach.
792 */
793void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
794{
795        WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
796}
797EXPORT_SYMBOL_GPL(devm_pwm_put);
798
799/**
800  * pwm_can_sleep() - report whether PWM access will sleep
801  * @pwm: PWM device
802  *
803  * It returns true if accessing the PWM can sleep, false otherwise.
804  */
805bool pwm_can_sleep(struct pwm_device *pwm)
806{
807        return pwm->chip->can_sleep;
808}
809EXPORT_SYMBOL_GPL(pwm_can_sleep);
810
811#ifdef CONFIG_DEBUG_FS
812static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
813{
814        unsigned int i;
815
816        for (i = 0; i < chip->npwm; i++) {
817                struct pwm_device *pwm = &chip->pwms[i];
818
819                seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
820
821                if (test_bit(PWMF_REQUESTED, &pwm->flags))
822                        seq_puts(s, " requested");
823
824                if (test_bit(PWMF_ENABLED, &pwm->flags))
825                        seq_puts(s, " enabled");
826
827                seq_puts(s, "\n");
828        }
829}
830
831static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
832{
833        mutex_lock(&pwm_lock);
834        s->private = "";
835
836        return seq_list_start(&pwm_chips, *pos);
837}
838
839static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
840{
841        s->private = "\n";
842
843        return seq_list_next(v, &pwm_chips, pos);
844}
845
846static void pwm_seq_stop(struct seq_file *s, void *v)
847{
848        mutex_unlock(&pwm_lock);
849}
850
851static int pwm_seq_show(struct seq_file *s, void *v)
852{
853        struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
854
855        seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
856                   chip->dev->bus ? chip->dev->bus->name : "no-bus",
857                   dev_name(chip->dev), chip->npwm,
858                   (chip->npwm != 1) ? "s" : "");
859
860        if (chip->ops->dbg_show)
861                chip->ops->dbg_show(chip, s);
862        else
863                pwm_dbg_show(chip, s);
864
865        return 0;
866}
867
868static const struct seq_operations pwm_seq_ops = {
869        .start = pwm_seq_start,
870        .next = pwm_seq_next,
871        .stop = pwm_seq_stop,
872        .show = pwm_seq_show,
873};
874
875static int pwm_seq_open(struct inode *inode, struct file *file)
876{
877        return seq_open(file, &pwm_seq_ops);
878}
879
880static const struct file_operations pwm_debugfs_ops = {
881        .owner = THIS_MODULE,
882        .open = pwm_seq_open,
883        .read = seq_read,
884        .llseek = seq_lseek,
885        .release = seq_release,
886};
887
888static int __init pwm_debugfs_init(void)
889{
890        debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
891                            &pwm_debugfs_ops);
892
893        return 0;
894}
895
896subsys_initcall(pwm_debugfs_init);
897#endif /* CONFIG_DEBUG_FS */
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