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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)
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 *
204 * Returns: 0 on success or a negative error code on failure.
205 */
206int pwm_set_chip_data(struct pwm_device *pwm, void *data)
207{
208 if (!pwm)
209 return -EINVAL;
210
211 pwm->chip_data = data;
212
213 return 0;
214}
215EXPORT_SYMBOL_GPL(pwm_set_chip_data);
216
217/**
218 * pwm_get_chip_data() - get private chip data for a PWM
219 * @pwm: PWM device
220 *
221 * Returns: A pointer to the chip-private data for the PWM device.
222 */
223void *pwm_get_chip_data(struct pwm_device *pwm)
224{
225 return pwm ? pwm->chip_data : NULL;
226}
227EXPORT_SYMBOL_GPL(pwm_get_chip_data);
228
229/**
230 * pwmchip_add_with_polarity() - register a new PWM chip
231 * @chip: the PWM chip to add
232 * @polarity: initial polarity of PWM channels
233 *
234 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
235 * will be used. The initial polarity for all channels is specified by the
236 * @polarity parameter.
237 *
238 * Returns: 0 on success or a negative error code on failure.
239 */
240int pwmchip_add_with_polarity(struct pwm_chip *chip,
241 enum pwm_polarity polarity)
242{
243 struct pwm_device *pwm;
244 unsigned int i;
245 int ret;
246
247 if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
248 !chip->ops->enable || !chip->ops->disable || !chip->npwm)
249 return -EINVAL;
250
251 mutex_lock(&pwm_lock);
252
253 ret = alloc_pwms(chip->base, chip->npwm);
254 if (ret < 0)
255 goto out;
256
257 chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
258 if (!chip->pwms) {
259 ret = -ENOMEM;
260 goto out;
261 }
262
263 chip->base = ret;
264
265 for (i = 0; i < chip->npwm; i++) {
266 pwm = &chip->pwms[i];
267
268 pwm->chip = chip;
269 pwm->pwm = chip->base + i;
270 pwm->hwpwm = i;
271 pwm->polarity = polarity;
272 mutex_init(&pwm->lock);
273
274 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
275 }
276
277 bitmap_set(allocated_pwms, chip->base, chip->npwm);
278
279 INIT_LIST_HEAD(&chip->list);
280 list_add(&chip->list, &pwm_chips);
281
282 ret = 0;
283
284 if (IS_ENABLED(CONFIG_OF))
285 of_pwmchip_add(chip);
286
287 pwmchip_sysfs_export(chip);
288
289out:
290 mutex_unlock(&pwm_lock);
291 return ret;
292}
293EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
294
295/**
296 * pwmchip_add() - register a new PWM chip
297 * @chip: the PWM chip to add
298 *
299 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
300 * will be used. The initial polarity for all channels is normal.
301 *
302 * Returns: 0 on success or a negative error code on failure.
303 */
304int pwmchip_add(struct pwm_chip *chip)
305{
306 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
307}
308EXPORT_SYMBOL_GPL(pwmchip_add);
309
310/**
311 * pwmchip_remove() - remove a PWM chip
312 * @chip: the PWM chip to remove
313 *
314 * Removes a PWM chip. This function may return busy if the PWM chip provides
315 * a PWM device that is still requested.
316 *
317 * Returns: 0 on success or a negative error code on failure.
318 */
319int pwmchip_remove(struct pwm_chip *chip)
320{
321 unsigned int i;
322 int ret = 0;
323
324 mutex_lock(&pwm_lock);
325
326 for (i = 0; i < chip->npwm; i++) {
327 struct pwm_device *pwm = &chip->pwms[i];
328
329 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
330 ret = -EBUSY;
331 goto out;
332 }
333 }
334
335 list_del_init(&chip->list);
336
337 if (IS_ENABLED(CONFIG_OF))
338 of_pwmchip_remove(chip);
339
340 free_pwms(chip);
341
342 pwmchip_sysfs_unexport(chip);
343
344out:
345 mutex_unlock(&pwm_lock);
346 return ret;
347}
348EXPORT_SYMBOL_GPL(pwmchip_remove);
349
350/**
351 * pwm_request() - request a PWM device
352 * @pwm: global PWM device index
353 * @label: PWM device label
354 *
355 * This function is deprecated, use pwm_get() instead.
356 *
357 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
358 * failure.
359 */
360struct pwm_device *pwm_request(int pwm, const char *label)
361{
362 struct pwm_device *dev;
363 int err;
364
365 if (pwm < 0 || pwm >= MAX_PWMS)
366 return ERR_PTR(-EINVAL);
367
368 mutex_lock(&pwm_lock);
369
370 dev = pwm_to_device(pwm);
371 if (!dev) {
372 dev = ERR_PTR(-EPROBE_DEFER);
373 goto out;
374 }
375
376 err = pwm_device_request(dev, label);
377 if (err < 0)
378 dev = ERR_PTR(err);
379
380out:
381 mutex_unlock(&pwm_lock);
382
383 return dev;
384}
385EXPORT_SYMBOL_GPL(pwm_request);
386
387/**
388 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
389 * @chip: PWM chip
390 * @index: per-chip index of the PWM to request
391 * @label: a literal description string of this PWM
392 *
393 * Returns: A pointer to the PWM device at the given index of the given PWM
394 * chip. A negative error code is returned if the index is not valid for the
395 * specified PWM chip or if the PWM device cannot be requested.
396 */
397struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
398 unsigned int index,
399 const char *label)
400{
401 struct pwm_device *pwm;
402 int err;
403
404 if (!chip || index >= chip->npwm)
405 return ERR_PTR(-EINVAL);
406
407 mutex_lock(&pwm_lock);
408 pwm = &chip->pwms[index];
409
410 err = pwm_device_request(pwm, label);
411 if (err < 0)
412 pwm = ERR_PTR(err);
413
414 mutex_unlock(&pwm_lock);
415 return pwm;
416}
417EXPORT_SYMBOL_GPL(pwm_request_from_chip);
418
419/**
420 * pwm_free() - free a PWM device
421 * @pwm: PWM device
422 *
423 * This function is deprecated, use pwm_put() instead.
424 */
425void pwm_free(struct pwm_device *pwm)
426{
427 pwm_put(pwm);
428}
429EXPORT_SYMBOL_GPL(pwm_free);
430
431/**
432 * pwm_config() - change a PWM device configuration
433 * @pwm: PWM device
434 * @duty_ns: "on" time (in nanoseconds)
435 * @period_ns: duration (in nanoseconds) of one cycle
436 *
437 * Returns: 0 on success or a negative error code on failure.
438 */
439int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
440{
441 int err;
442
443 if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
444 return -EINVAL;
445
446 err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
447 if (err)
448 return err;
449
450 pwm->duty_cycle = duty_ns;
451 pwm->period = period_ns;
452
453 return 0;
454}
455EXPORT_SYMBOL_GPL(pwm_config);
456
457/**
458 * pwm_set_polarity() - configure the polarity of a PWM signal
459 * @pwm: PWM device
460 * @polarity: new polarity of the PWM signal
461 *
462 * Note that the polarity cannot be configured while the PWM device is
463 * enabled.
464 *
465 * Returns: 0 on success or a negative error code on failure.
466 */
467int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
468{
469 int err;
470
471 if (!pwm || !pwm->chip->ops)
472 return -EINVAL;
473
474 if (!pwm->chip->ops->set_polarity)
475 return -ENOSYS;
476
477 mutex_lock(&pwm->lock);
478
479 if (pwm_is_enabled(pwm)) {
480 err = -EBUSY;
481 goto unlock;
482 }
483
484 err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
485 if (err)
486 goto unlock;
487
488 pwm->polarity = polarity;
489
490unlock:
491 mutex_unlock(&pwm->lock);
492 return err;
493}
494EXPORT_SYMBOL_GPL(pwm_set_polarity);
495
496/**
497 * pwm_enable() - start a PWM output toggling
498 * @pwm: PWM device
499 *
500 * Returns: 0 on success or a negative error code on failure.
501 */
502int pwm_enable(struct pwm_device *pwm)
503{
504 int err = 0;
505
506 if (!pwm)
507 return -EINVAL;
508
509 mutex_lock(&pwm->lock);
510
511 if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
512 err = pwm->chip->ops->enable(pwm->chip, pwm);
513 if (err)
514 clear_bit(PWMF_ENABLED, &pwm->flags);
515 }
516
517 mutex_unlock(&pwm->lock);
518
519 return err;
520}
521EXPORT_SYMBOL_GPL(pwm_enable);
522
523/**
524 * pwm_disable() - stop a PWM output toggling
525 * @pwm: PWM device
526 */
527void pwm_disable(struct pwm_device *pwm)
528{
529 if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
530 pwm->chip->ops->disable(pwm->chip, pwm);
531}
532EXPORT_SYMBOL_GPL(pwm_disable);
533
534static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
535{
536 struct pwm_chip *chip;
537
538 mutex_lock(&pwm_lock);
539
540 list_for_each_entry(chip, &pwm_chips, list)
541 if (chip->dev && chip->dev->of_node == np) {
542 mutex_unlock(&pwm_lock);
543 return chip;
544 }
545
546 mutex_unlock(&pwm_lock);
547
548 return ERR_PTR(-EPROBE_DEFER);
549}
550
551/**
552 * of_pwm_get() - request a PWM via the PWM framework
553 * @np: device node to get the PWM from
554 * @con_id: consumer name
555 *
556 * Returns the PWM device parsed from the phandle and index specified in the
557 * "pwms" property of a device tree node or a negative error-code on failure.
558 * Values parsed from the device tree are stored in the returned PWM device
559 * object.
560 *
561 * If con_id is NULL, the first PWM device listed in the "pwms" property will
562 * be requested. Otherwise the "pwm-names" property is used to do a reverse
563 * lookup of the PWM index. This also means that the "pwm-names" property
564 * becomes mandatory for devices that look up the PWM device via the con_id
565 * parameter.
566 *
567 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
568 * error code on failure.
569 */
570struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
571{
572 struct pwm_device *pwm = NULL;
573 struct of_phandle_args args;
574 struct pwm_chip *pc;
575 int index = 0;
576 int err;
577
578 if (con_id) {
579 index = of_property_match_string(np, "pwm-names", con_id);
580 if (index < 0)
581 return ERR_PTR(index);
582 }
583
584 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
585 &args);
586 if (err) {
587 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
588 return ERR_PTR(err);
589 }
590
591 pc = of_node_to_pwmchip(args.np);
592 if (IS_ERR(pc)) {
593 pr_debug("%s(): PWM chip not found\n", __func__);
594 pwm = ERR_CAST(pc);
595 goto put;
596 }
597
598 if (args.args_count != pc->of_pwm_n_cells) {
599 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
600 args.np->full_name);
601 pwm = ERR_PTR(-EINVAL);
602 goto put;
603 }
604
605 pwm = pc->of_xlate(pc, &args);
606 if (IS_ERR(pwm))
607 goto put;
608
609 /*
610 * If a consumer name was not given, try to look it up from the
611 * "pwm-names" property if it exists. Otherwise use the name of
612 * the user device node.
613 */
614 if (!con_id) {
615 err = of_property_read_string_index(np, "pwm-names", index,
616 &con_id);
617 if (err < 0)
618 con_id = np->name;
619 }
620
621 pwm->label = con_id;
622
623put:
624 of_node_put(args.np);
625
626 return pwm;
627}
628EXPORT_SYMBOL_GPL(of_pwm_get);
629
630/**
631 * pwm_add_table() - register PWM device consumers
632 * @table: array of consumers to register
633 * @num: number of consumers in table
634 */
635void pwm_add_table(struct pwm_lookup *table, size_t num)
636{
637 mutex_lock(&pwm_lookup_lock);
638
639 while (num--) {
640 list_add_tail(&table->list, &pwm_lookup_list);
641 table++;
642 }
643
644 mutex_unlock(&pwm_lookup_lock);
645}
646
647/**
648 * pwm_remove_table() - unregister PWM device consumers
649 * @table: array of consumers to unregister
650 * @num: number of consumers in table
651 */
652void pwm_remove_table(struct pwm_lookup *table, size_t num)
653{
654 mutex_lock(&pwm_lookup_lock);
655
656 while (num--) {
657 list_del(&table->list);
658 table++;
659 }
660
661 mutex_unlock(&pwm_lookup_lock);
662}
663
664/**
665 * pwm_get() - look up and request a PWM device
666 * @dev: device for PWM consumer
667 * @con_id: consumer name
668 *
669 * Lookup is first attempted using DT. If the device was not instantiated from
670 * a device tree, a PWM chip and a relative index is looked up via a table
671 * supplied by board setup code (see pwm_add_table()).
672 *
673 * Once a PWM chip has been found the specified PWM device will be requested
674 * and is ready to be used.
675 *
676 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
677 * error code on failure.
678 */
679struct pwm_device *pwm_get(struct device *dev, const char *con_id)
680{
681 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
682 const char *dev_id = dev ? dev_name(dev) : NULL;
683 struct pwm_chip *chip = NULL;
684 unsigned int best = 0;
685 struct pwm_lookup *p, *chosen = NULL;
686 unsigned int match;
687
688 /* look up via DT first */
689 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
690 return of_pwm_get(dev->of_node, con_id);
691
692 /*
693 * We look up the provider in the static table typically provided by
694 * board setup code. We first try to lookup the consumer device by
695 * name. If the consumer device was passed in as NULL or if no match
696 * was found, we try to find the consumer by directly looking it up
697 * by name.
698 *
699 * If a match is found, the provider PWM chip is looked up by name
700 * and a PWM device is requested using the PWM device per-chip index.
701 *
702 * The lookup algorithm was shamelessly taken from the clock
703 * framework:
704 *
705 * We do slightly fuzzy matching here:
706 * An entry with a NULL ID is assumed to be a wildcard.
707 * If an entry has a device ID, it must match
708 * If an entry has a connection ID, it must match
709 * Then we take the most specific entry - with the following order
710 * of precedence: dev+con > dev only > con only.
711 */
712 mutex_lock(&pwm_lookup_lock);
713
714 list_for_each_entry(p, &pwm_lookup_list, list) {
715 match = 0;
716
717 if (p->dev_id) {
718 if (!dev_id || strcmp(p->dev_id, dev_id))
719 continue;
720
721 match += 2;
722 }
723
724 if (p->con_id) {
725 if (!con_id || strcmp(p->con_id, con_id))
726 continue;
727
728 match += 1;
729 }
730
731 if (match > best) {
732 chosen = p;
733
734 if (match != 3)
735 best = match;
736 else
737 break;
738 }
739 }
740
741 if (!chosen) {
742 pwm = ERR_PTR(-ENODEV);
743 goto out;
744 }
745
746 chip = pwmchip_find_by_name(chosen->provider);
747 if (!chip)
748 goto out;
749
750 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
751 if (IS_ERR(pwm))
752 goto out;
753
754 pwm_set_period(pwm, chosen->period);
755 pwm_set_polarity(pwm, chosen->polarity);
756
757out:
758 mutex_unlock(&pwm_lookup_lock);
759 return pwm;
760}
761EXPORT_SYMBOL_GPL(pwm_get);
762
763/**
764 * pwm_put() - release a PWM device
765 * @pwm: PWM device
766 */
767void pwm_put(struct pwm_device *pwm)
768{
769 if (!pwm)
770 return;
771
772 mutex_lock(&pwm_lock);
773
774 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
775 pr_warn("PWM device already freed\n");
776 goto out;
777 }
778
779 if (pwm->chip->ops->free)
780 pwm->chip->ops->free(pwm->chip, pwm);
781
782 pwm->label = NULL;
783
784 module_put(pwm->chip->ops->owner);
785out:
786 mutex_unlock(&pwm_lock);
787}
788EXPORT_SYMBOL_GPL(pwm_put);
789
790static void devm_pwm_release(struct device *dev, void *res)
791{
792 pwm_put(*(struct pwm_device **)res);
793}
794
795/**
796 * devm_pwm_get() - resource managed pwm_get()
797 * @dev: device for PWM consumer
798 * @con_id: consumer name
799 *
800 * This function performs like pwm_get() but the acquired PWM device will
801 * automatically be released on driver detach.
802 *
803 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
804 * error code on failure.
805 */
806struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
807{
808 struct pwm_device **ptr, *pwm;
809
810 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
811 if (!ptr)
812 return ERR_PTR(-ENOMEM);
813
814 pwm = pwm_get(dev, con_id);
815 if (!IS_ERR(pwm)) {
816 *ptr = pwm;
817 devres_add(dev, ptr);
818 } else {
819 devres_free(ptr);
820 }
821
822 return pwm;
823}
824EXPORT_SYMBOL_GPL(devm_pwm_get);
825
826/**
827 * devm_of_pwm_get() - resource managed of_pwm_get()
828 * @dev: device for PWM consumer
829 * @np: device node to get the PWM from
830 * @con_id: consumer name
831 *
832 * This function performs like of_pwm_get() but the acquired PWM device will
833 * automatically be released on driver detach.
834 *
835 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
836 * error code on failure.
837 */
838struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
839 const char *con_id)
840{
841 struct pwm_device **ptr, *pwm;
842
843 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
844 if (!ptr)
845 return ERR_PTR(-ENOMEM);
846
847 pwm = of_pwm_get(np, con_id);
848 if (!IS_ERR(pwm)) {
849 *ptr = pwm;
850 devres_add(dev, ptr);
851 } else {
852 devres_free(ptr);
853 }
854
855 return pwm;
856}
857EXPORT_SYMBOL_GPL(devm_of_pwm_get);
858
859static int devm_pwm_match(struct device *dev, void *res, void *data)
860{
861 struct pwm_device **p = res;
862
863 if (WARN_ON(!p || !*p))
864 return 0;
865
866 return *p == data;
867}
868
869/**
870 * devm_pwm_put() - resource managed pwm_put()
871 * @dev: device for PWM consumer
872 * @pwm: PWM device
873 *
874 * Release a PWM previously allocated using devm_pwm_get(). Calling this
875 * function is usually not needed because devm-allocated resources are
876 * automatically released on driver detach.
877 */
878void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
879{
880 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
881}
882EXPORT_SYMBOL_GPL(devm_pwm_put);
883
884/**
885 * pwm_can_sleep() - report whether PWM access will sleep
886 * @pwm: PWM device
887 *
888 * Returns: True if accessing the PWM can sleep, false otherwise.
889 */
890bool pwm_can_sleep(struct pwm_device *pwm)
891{
892 return true;
893}
894EXPORT_SYMBOL_GPL(pwm_can_sleep);
895
896#ifdef CONFIG_DEBUG_FS
897static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
898{
899 unsigned int i;
900
901 for (i = 0; i < chip->npwm; i++) {
902 struct pwm_device *pwm = &chip->pwms[i];
903
904 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
905
906 if (test_bit(PWMF_REQUESTED, &pwm->flags))
907 seq_puts(s, " requested");
908
909 if (pwm_is_enabled(pwm))
910 seq_puts(s, " enabled");
911
912 seq_puts(s, "\n");
913 }
914}
915
916static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
917{
918 mutex_lock(&pwm_lock);
919 s->private = "";
920
921 return seq_list_start(&pwm_chips, *pos);
922}
923
924static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
925{
926 s->private = "\n";
927
928 return seq_list_next(v, &pwm_chips, pos);
929}
930
931static void pwm_seq_stop(struct seq_file *s, void *v)
932{
933 mutex_unlock(&pwm_lock);
934}
935
936static int pwm_seq_show(struct seq_file *s, void *v)
937{
938 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
939
940 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
941 chip->dev->bus ? chip->dev->bus->name : "no-bus",
942 dev_name(chip->dev), chip->npwm,
943 (chip->npwm != 1) ? "s" : "");
944
945 if (chip->ops->dbg_show)
946 chip->ops->dbg_show(chip, s);
947 else
948 pwm_dbg_show(chip, s);
949
950 return 0;
951}
952
953static const struct seq_operations pwm_seq_ops = {
954 .start = pwm_seq_start,
955 .next = pwm_seq_next,
956 .stop = pwm_seq_stop,
957 .show = pwm_seq_show,
958};
959
960static int pwm_seq_open(struct inode *inode, struct file *file)
961{
962 return seq_open(file, &pwm_seq_ops);
963}
964
965static const struct file_operations pwm_debugfs_ops = {
966 .owner = THIS_MODULE,
967 .open = pwm_seq_open,
968 .read = seq_read,
969 .llseek = seq_lseek,
970 .release = seq_release,
971};
972
973static int __init pwm_debugfs_init(void)
974{
975 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
976 &pwm_debugfs_ops);
977
978 return 0;
979}
980subsys_initcall(pwm_debugfs_init);
981#endif /* CONFIG_DEBUG_FS */
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
79 radix_tree_delete(&pwm_tree, pwm->pwm);
80 }
81
82 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
83
84 kfree(chip->pwms);
85 chip->pwms = NULL;
86}
87
88static struct pwm_chip *pwmchip_find_by_name(const char *name)
89{
90 struct pwm_chip *chip;
91
92 if (!name)
93 return NULL;
94
95 mutex_lock(&pwm_lock);
96
97 list_for_each_entry(chip, &pwm_chips, list) {
98 const char *chip_name = dev_name(chip->dev);
99
100 if (chip_name && strcmp(chip_name, name) == 0) {
101 mutex_unlock(&pwm_lock);
102 return chip;
103 }
104 }
105
106 mutex_unlock(&pwm_lock);
107
108 return NULL;
109}
110
111static int pwm_device_request(struct pwm_device *pwm, const char *label)
112{
113 int err;
114
115 if (test_bit(PWMF_REQUESTED, &pwm->flags))
116 return -EBUSY;
117
118 if (!try_module_get(pwm->chip->ops->owner))
119 return -ENODEV;
120
121 if (pwm->chip->ops->request) {
122 err = pwm->chip->ops->request(pwm->chip, pwm);
123 if (err) {
124 module_put(pwm->chip->ops->owner);
125 return err;
126 }
127 }
128
129 set_bit(PWMF_REQUESTED, &pwm->flags);
130 pwm->label = label;
131
132 return 0;
133}
134
135struct pwm_device *
136of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
137{
138 struct pwm_device *pwm;
139
140 if (pc->of_pwm_n_cells < 3)
141 return ERR_PTR(-EINVAL);
142
143 if (args->args[0] >= pc->npwm)
144 return ERR_PTR(-EINVAL);
145
146 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
147 if (IS_ERR(pwm))
148 return pwm;
149
150 pwm->args.period = args->args[1];
151
152 if (args->args[2] & PWM_POLARITY_INVERTED)
153 pwm->args.polarity = PWM_POLARITY_INVERSED;
154 else
155 pwm->args.polarity = PWM_POLARITY_NORMAL;
156
157 return pwm;
158}
159EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
160
161static struct pwm_device *
162of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
163{
164 struct pwm_device *pwm;
165
166 if (pc->of_pwm_n_cells < 2)
167 return ERR_PTR(-EINVAL);
168
169 if (args->args[0] >= pc->npwm)
170 return ERR_PTR(-EINVAL);
171
172 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
173 if (IS_ERR(pwm))
174 return pwm;
175
176 pwm->args.period = args->args[1];
177
178 return pwm;
179}
180
181static void of_pwmchip_add(struct pwm_chip *chip)
182{
183 if (!chip->dev || !chip->dev->of_node)
184 return;
185
186 if (!chip->of_xlate) {
187 chip->of_xlate = of_pwm_simple_xlate;
188 chip->of_pwm_n_cells = 2;
189 }
190
191 of_node_get(chip->dev->of_node);
192}
193
194static void of_pwmchip_remove(struct pwm_chip *chip)
195{
196 if (chip->dev)
197 of_node_put(chip->dev->of_node);
198}
199
200/**
201 * pwm_set_chip_data() - set private chip data for a PWM
202 * @pwm: PWM device
203 * @data: pointer to chip-specific data
204 *
205 * Returns: 0 on success or a negative error code on failure.
206 */
207int pwm_set_chip_data(struct pwm_device *pwm, void *data)
208{
209 if (!pwm)
210 return -EINVAL;
211
212 pwm->chip_data = data;
213
214 return 0;
215}
216EXPORT_SYMBOL_GPL(pwm_set_chip_data);
217
218/**
219 * pwm_get_chip_data() - get private chip data for a PWM
220 * @pwm: PWM device
221 *
222 * Returns: A pointer to the chip-private data for the PWM device.
223 */
224void *pwm_get_chip_data(struct pwm_device *pwm)
225{
226 return pwm ? pwm->chip_data : NULL;
227}
228EXPORT_SYMBOL_GPL(pwm_get_chip_data);
229
230static bool pwm_ops_check(const struct pwm_ops *ops)
231{
232 /* driver supports legacy, non-atomic operation */
233 if (ops->config && ops->enable && ops->disable)
234 return true;
235
236 /* driver supports atomic operation */
237 if (ops->apply)
238 return true;
239
240 return false;
241}
242
243/**
244 * pwmchip_add_with_polarity() - register a new PWM chip
245 * @chip: the PWM chip to add
246 * @polarity: initial polarity of PWM channels
247 *
248 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
249 * will be used. The initial polarity for all channels is specified by the
250 * @polarity parameter.
251 *
252 * Returns: 0 on success or a negative error code on failure.
253 */
254int pwmchip_add_with_polarity(struct pwm_chip *chip,
255 enum pwm_polarity polarity)
256{
257 struct pwm_device *pwm;
258 unsigned int i;
259 int ret;
260
261 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
262 return -EINVAL;
263
264 if (!pwm_ops_check(chip->ops))
265 return -EINVAL;
266
267 mutex_lock(&pwm_lock);
268
269 ret = alloc_pwms(chip->base, chip->npwm);
270 if (ret < 0)
271 goto out;
272
273 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
274 if (!chip->pwms) {
275 ret = -ENOMEM;
276 goto out;
277 }
278
279 chip->base = ret;
280
281 for (i = 0; i < chip->npwm; i++) {
282 pwm = &chip->pwms[i];
283
284 pwm->chip = chip;
285 pwm->pwm = chip->base + i;
286 pwm->hwpwm = i;
287 pwm->state.polarity = polarity;
288
289 if (chip->ops->get_state)
290 chip->ops->get_state(chip, pwm, &pwm->state);
291
292 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
293 }
294
295 bitmap_set(allocated_pwms, chip->base, chip->npwm);
296
297 INIT_LIST_HEAD(&chip->list);
298 list_add(&chip->list, &pwm_chips);
299
300 ret = 0;
301
302 if (IS_ENABLED(CONFIG_OF))
303 of_pwmchip_add(chip);
304
305 pwmchip_sysfs_export(chip);
306
307out:
308 mutex_unlock(&pwm_lock);
309 return ret;
310}
311EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
312
313/**
314 * pwmchip_add() - register a new PWM chip
315 * @chip: the PWM chip to add
316 *
317 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
318 * will be used. The initial polarity for all channels is normal.
319 *
320 * Returns: 0 on success or a negative error code on failure.
321 */
322int pwmchip_add(struct pwm_chip *chip)
323{
324 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
325}
326EXPORT_SYMBOL_GPL(pwmchip_add);
327
328/**
329 * pwmchip_remove() - remove a PWM chip
330 * @chip: the PWM chip to remove
331 *
332 * Removes a PWM chip. This function may return busy if the PWM chip provides
333 * a PWM device that is still requested.
334 *
335 * Returns: 0 on success or a negative error code on failure.
336 */
337int pwmchip_remove(struct pwm_chip *chip)
338{
339 unsigned int i;
340 int ret = 0;
341
342 pwmchip_sysfs_unexport_children(chip);
343
344 mutex_lock(&pwm_lock);
345
346 for (i = 0; i < chip->npwm; i++) {
347 struct pwm_device *pwm = &chip->pwms[i];
348
349 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
350 ret = -EBUSY;
351 goto out;
352 }
353 }
354
355 list_del_init(&chip->list);
356
357 if (IS_ENABLED(CONFIG_OF))
358 of_pwmchip_remove(chip);
359
360 free_pwms(chip);
361
362 pwmchip_sysfs_unexport(chip);
363
364out:
365 mutex_unlock(&pwm_lock);
366 return ret;
367}
368EXPORT_SYMBOL_GPL(pwmchip_remove);
369
370/**
371 * pwm_request() - request a PWM device
372 * @pwm: global PWM device index
373 * @label: PWM device label
374 *
375 * This function is deprecated, use pwm_get() instead.
376 *
377 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
378 * failure.
379 */
380struct pwm_device *pwm_request(int pwm, const char *label)
381{
382 struct pwm_device *dev;
383 int err;
384
385 if (pwm < 0 || pwm >= MAX_PWMS)
386 return ERR_PTR(-EINVAL);
387
388 mutex_lock(&pwm_lock);
389
390 dev = pwm_to_device(pwm);
391 if (!dev) {
392 dev = ERR_PTR(-EPROBE_DEFER);
393 goto out;
394 }
395
396 err = pwm_device_request(dev, label);
397 if (err < 0)
398 dev = ERR_PTR(err);
399
400out:
401 mutex_unlock(&pwm_lock);
402
403 return dev;
404}
405EXPORT_SYMBOL_GPL(pwm_request);
406
407/**
408 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
409 * @chip: PWM chip
410 * @index: per-chip index of the PWM to request
411 * @label: a literal description string of this PWM
412 *
413 * Returns: A pointer to the PWM device at the given index of the given PWM
414 * chip. A negative error code is returned if the index is not valid for the
415 * specified PWM chip or if the PWM device cannot be requested.
416 */
417struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
418 unsigned int index,
419 const char *label)
420{
421 struct pwm_device *pwm;
422 int err;
423
424 if (!chip || index >= chip->npwm)
425 return ERR_PTR(-EINVAL);
426
427 mutex_lock(&pwm_lock);
428 pwm = &chip->pwms[index];
429
430 err = pwm_device_request(pwm, label);
431 if (err < 0)
432 pwm = ERR_PTR(err);
433
434 mutex_unlock(&pwm_lock);
435 return pwm;
436}
437EXPORT_SYMBOL_GPL(pwm_request_from_chip);
438
439/**
440 * pwm_free() - free a PWM device
441 * @pwm: PWM device
442 *
443 * This function is deprecated, use pwm_put() instead.
444 */
445void pwm_free(struct pwm_device *pwm)
446{
447 pwm_put(pwm);
448}
449EXPORT_SYMBOL_GPL(pwm_free);
450
451/**
452 * pwm_apply_state() - atomically apply a new state to a PWM device
453 * @pwm: PWM device
454 * @state: new state to apply. This can be adjusted by the PWM driver
455 * if the requested config is not achievable, for example,
456 * ->duty_cycle and ->period might be approximated.
457 */
458int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
459{
460 int err;
461
462 if (!pwm || !state || !state->period ||
463 state->duty_cycle > state->period)
464 return -EINVAL;
465
466 if (!memcmp(state, &pwm->state, sizeof(*state)))
467 return 0;
468
469 if (pwm->chip->ops->apply) {
470 err = pwm->chip->ops->apply(pwm->chip, pwm, state);
471 if (err)
472 return err;
473
474 pwm->state = *state;
475 } else {
476 /*
477 * FIXME: restore the initial state in case of error.
478 */
479 if (state->polarity != pwm->state.polarity) {
480 if (!pwm->chip->ops->set_polarity)
481 return -ENOTSUPP;
482
483 /*
484 * Changing the polarity of a running PWM is
485 * only allowed when the PWM driver implements
486 * ->apply().
487 */
488 if (pwm->state.enabled) {
489 pwm->chip->ops->disable(pwm->chip, pwm);
490 pwm->state.enabled = false;
491 }
492
493 err = pwm->chip->ops->set_polarity(pwm->chip, pwm,
494 state->polarity);
495 if (err)
496 return err;
497
498 pwm->state.polarity = state->polarity;
499 }
500
501 if (state->period != pwm->state.period ||
502 state->duty_cycle != pwm->state.duty_cycle) {
503 err = pwm->chip->ops->config(pwm->chip, pwm,
504 state->duty_cycle,
505 state->period);
506 if (err)
507 return err;
508
509 pwm->state.duty_cycle = state->duty_cycle;
510 pwm->state.period = state->period;
511 }
512
513 if (state->enabled != pwm->state.enabled) {
514 if (state->enabled) {
515 err = pwm->chip->ops->enable(pwm->chip, pwm);
516 if (err)
517 return err;
518 } else {
519 pwm->chip->ops->disable(pwm->chip, pwm);
520 }
521
522 pwm->state.enabled = state->enabled;
523 }
524 }
525
526 return 0;
527}
528EXPORT_SYMBOL_GPL(pwm_apply_state);
529
530/**
531 * pwm_capture() - capture and report a PWM signal
532 * @pwm: PWM device
533 * @result: structure to fill with capture result
534 * @timeout: time to wait, in milliseconds, before giving up on capture
535 *
536 * Returns: 0 on success or a negative error code on failure.
537 */
538int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
539 unsigned long timeout)
540{
541 int err;
542
543 if (!pwm || !pwm->chip->ops)
544 return -EINVAL;
545
546 if (!pwm->chip->ops->capture)
547 return -ENOSYS;
548
549 mutex_lock(&pwm_lock);
550 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
551 mutex_unlock(&pwm_lock);
552
553 return err;
554}
555EXPORT_SYMBOL_GPL(pwm_capture);
556
557/**
558 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
559 * @pwm: PWM device
560 *
561 * This function will adjust the PWM config to the PWM arguments provided
562 * by the DT or PWM lookup table. This is particularly useful to adapt
563 * the bootloader config to the Linux one.
564 */
565int pwm_adjust_config(struct pwm_device *pwm)
566{
567 struct pwm_state state;
568 struct pwm_args pargs;
569
570 pwm_get_args(pwm, &pargs);
571 pwm_get_state(pwm, &state);
572
573 /*
574 * If the current period is zero it means that either the PWM driver
575 * does not support initial state retrieval or the PWM has not yet
576 * been configured.
577 *
578 * In either case, we setup the new period and polarity, and assign a
579 * duty cycle of 0.
580 */
581 if (!state.period) {
582 state.duty_cycle = 0;
583 state.period = pargs.period;
584 state.polarity = pargs.polarity;
585
586 return pwm_apply_state(pwm, &state);
587 }
588
589 /*
590 * Adjust the PWM duty cycle/period based on the period value provided
591 * in PWM args.
592 */
593 if (pargs.period != state.period) {
594 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
595
596 do_div(dutycycle, state.period);
597 state.duty_cycle = dutycycle;
598 state.period = pargs.period;
599 }
600
601 /*
602 * If the polarity changed, we should also change the duty cycle.
603 */
604 if (pargs.polarity != state.polarity) {
605 state.polarity = pargs.polarity;
606 state.duty_cycle = state.period - state.duty_cycle;
607 }
608
609 return pwm_apply_state(pwm, &state);
610}
611EXPORT_SYMBOL_GPL(pwm_adjust_config);
612
613static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
614{
615 struct pwm_chip *chip;
616
617 mutex_lock(&pwm_lock);
618
619 list_for_each_entry(chip, &pwm_chips, list)
620 if (chip->dev && chip->dev->of_node == np) {
621 mutex_unlock(&pwm_lock);
622 return chip;
623 }
624
625 mutex_unlock(&pwm_lock);
626
627 return ERR_PTR(-EPROBE_DEFER);
628}
629
630/**
631 * of_pwm_get() - request a PWM via the PWM framework
632 * @np: device node to get the PWM from
633 * @con_id: consumer name
634 *
635 * Returns the PWM device parsed from the phandle and index specified in the
636 * "pwms" property of a device tree node or a negative error-code on failure.
637 * Values parsed from the device tree are stored in the returned PWM device
638 * object.
639 *
640 * If con_id is NULL, the first PWM device listed in the "pwms" property will
641 * be requested. Otherwise the "pwm-names" property is used to do a reverse
642 * lookup of the PWM index. This also means that the "pwm-names" property
643 * becomes mandatory for devices that look up the PWM device via the con_id
644 * parameter.
645 *
646 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
647 * error code on failure.
648 */
649struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
650{
651 struct pwm_device *pwm = NULL;
652 struct of_phandle_args args;
653 struct pwm_chip *pc;
654 int index = 0;
655 int err;
656
657 if (con_id) {
658 index = of_property_match_string(np, "pwm-names", con_id);
659 if (index < 0)
660 return ERR_PTR(index);
661 }
662
663 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
664 &args);
665 if (err) {
666 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
667 return ERR_PTR(err);
668 }
669
670 pc = of_node_to_pwmchip(args.np);
671 if (IS_ERR(pc)) {
672 pr_debug("%s(): PWM chip not found\n", __func__);
673 pwm = ERR_CAST(pc);
674 goto put;
675 }
676
677 if (args.args_count != pc->of_pwm_n_cells) {
678 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
679 args.np->full_name);
680 pwm = ERR_PTR(-EINVAL);
681 goto put;
682 }
683
684 pwm = pc->of_xlate(pc, &args);
685 if (IS_ERR(pwm))
686 goto put;
687
688 /*
689 * If a consumer name was not given, try to look it up from the
690 * "pwm-names" property if it exists. Otherwise use the name of
691 * the user device node.
692 */
693 if (!con_id) {
694 err = of_property_read_string_index(np, "pwm-names", index,
695 &con_id);
696 if (err < 0)
697 con_id = np->name;
698 }
699
700 pwm->label = con_id;
701
702put:
703 of_node_put(args.np);
704
705 return pwm;
706}
707EXPORT_SYMBOL_GPL(of_pwm_get);
708
709/**
710 * pwm_add_table() - register PWM device consumers
711 * @table: array of consumers to register
712 * @num: number of consumers in table
713 */
714void pwm_add_table(struct pwm_lookup *table, size_t num)
715{
716 mutex_lock(&pwm_lookup_lock);
717
718 while (num--) {
719 list_add_tail(&table->list, &pwm_lookup_list);
720 table++;
721 }
722
723 mutex_unlock(&pwm_lookup_lock);
724}
725
726/**
727 * pwm_remove_table() - unregister PWM device consumers
728 * @table: array of consumers to unregister
729 * @num: number of consumers in table
730 */
731void pwm_remove_table(struct pwm_lookup *table, size_t num)
732{
733 mutex_lock(&pwm_lookup_lock);
734
735 while (num--) {
736 list_del(&table->list);
737 table++;
738 }
739
740 mutex_unlock(&pwm_lookup_lock);
741}
742
743/**
744 * pwm_get() - look up and request a PWM device
745 * @dev: device for PWM consumer
746 * @con_id: consumer name
747 *
748 * Lookup is first attempted using DT. If the device was not instantiated from
749 * a device tree, a PWM chip and a relative index is looked up via a table
750 * supplied by board setup code (see pwm_add_table()).
751 *
752 * Once a PWM chip has been found the specified PWM device will be requested
753 * and is ready to be used.
754 *
755 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
756 * error code on failure.
757 */
758struct pwm_device *pwm_get(struct device *dev, const char *con_id)
759{
760 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
761 const char *dev_id = dev ? dev_name(dev) : NULL;
762 struct pwm_chip *chip = NULL;
763 unsigned int best = 0;
764 struct pwm_lookup *p, *chosen = NULL;
765 unsigned int match;
766
767 /* look up via DT first */
768 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
769 return of_pwm_get(dev->of_node, con_id);
770
771 /*
772 * We look up the provider in the static table typically provided by
773 * board setup code. We first try to lookup the consumer device by
774 * name. If the consumer device was passed in as NULL or if no match
775 * was found, we try to find the consumer by directly looking it up
776 * by name.
777 *
778 * If a match is found, the provider PWM chip is looked up by name
779 * and a PWM device is requested using the PWM device per-chip index.
780 *
781 * The lookup algorithm was shamelessly taken from the clock
782 * framework:
783 *
784 * We do slightly fuzzy matching here:
785 * An entry with a NULL ID is assumed to be a wildcard.
786 * If an entry has a device ID, it must match
787 * If an entry has a connection ID, it must match
788 * Then we take the most specific entry - with the following order
789 * of precedence: dev+con > dev only > con only.
790 */
791 mutex_lock(&pwm_lookup_lock);
792
793 list_for_each_entry(p, &pwm_lookup_list, list) {
794 match = 0;
795
796 if (p->dev_id) {
797 if (!dev_id || strcmp(p->dev_id, dev_id))
798 continue;
799
800 match += 2;
801 }
802
803 if (p->con_id) {
804 if (!con_id || strcmp(p->con_id, con_id))
805 continue;
806
807 match += 1;
808 }
809
810 if (match > best) {
811 chosen = p;
812
813 if (match != 3)
814 best = match;
815 else
816 break;
817 }
818 }
819
820 if (!chosen) {
821 pwm = ERR_PTR(-ENODEV);
822 goto out;
823 }
824
825 chip = pwmchip_find_by_name(chosen->provider);
826 if (!chip)
827 goto out;
828
829 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
830 if (IS_ERR(pwm))
831 goto out;
832
833 pwm->args.period = chosen->period;
834 pwm->args.polarity = chosen->polarity;
835
836out:
837 mutex_unlock(&pwm_lookup_lock);
838 return pwm;
839}
840EXPORT_SYMBOL_GPL(pwm_get);
841
842/**
843 * pwm_put() - release a PWM device
844 * @pwm: PWM device
845 */
846void pwm_put(struct pwm_device *pwm)
847{
848 if (!pwm)
849 return;
850
851 mutex_lock(&pwm_lock);
852
853 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
854 pr_warn("PWM device already freed\n");
855 goto out;
856 }
857
858 if (pwm->chip->ops->free)
859 pwm->chip->ops->free(pwm->chip, pwm);
860
861 pwm->label = NULL;
862
863 module_put(pwm->chip->ops->owner);
864out:
865 mutex_unlock(&pwm_lock);
866}
867EXPORT_SYMBOL_GPL(pwm_put);
868
869static void devm_pwm_release(struct device *dev, void *res)
870{
871 pwm_put(*(struct pwm_device **)res);
872}
873
874/**
875 * devm_pwm_get() - resource managed pwm_get()
876 * @dev: device for PWM consumer
877 * @con_id: consumer name
878 *
879 * This function performs like pwm_get() but the acquired PWM device will
880 * automatically be released on driver detach.
881 *
882 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
883 * error code on failure.
884 */
885struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
886{
887 struct pwm_device **ptr, *pwm;
888
889 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
890 if (!ptr)
891 return ERR_PTR(-ENOMEM);
892
893 pwm = pwm_get(dev, con_id);
894 if (!IS_ERR(pwm)) {
895 *ptr = pwm;
896 devres_add(dev, ptr);
897 } else {
898 devres_free(ptr);
899 }
900
901 return pwm;
902}
903EXPORT_SYMBOL_GPL(devm_pwm_get);
904
905/**
906 * devm_of_pwm_get() - resource managed of_pwm_get()
907 * @dev: device for PWM consumer
908 * @np: device node to get the PWM from
909 * @con_id: consumer name
910 *
911 * This function performs like of_pwm_get() but the acquired PWM device will
912 * automatically be released on driver detach.
913 *
914 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
915 * error code on failure.
916 */
917struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
918 const char *con_id)
919{
920 struct pwm_device **ptr, *pwm;
921
922 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
923 if (!ptr)
924 return ERR_PTR(-ENOMEM);
925
926 pwm = of_pwm_get(np, con_id);
927 if (!IS_ERR(pwm)) {
928 *ptr = pwm;
929 devres_add(dev, ptr);
930 } else {
931 devres_free(ptr);
932 }
933
934 return pwm;
935}
936EXPORT_SYMBOL_GPL(devm_of_pwm_get);
937
938static int devm_pwm_match(struct device *dev, void *res, void *data)
939{
940 struct pwm_device **p = res;
941
942 if (WARN_ON(!p || !*p))
943 return 0;
944
945 return *p == data;
946}
947
948/**
949 * devm_pwm_put() - resource managed pwm_put()
950 * @dev: device for PWM consumer
951 * @pwm: PWM device
952 *
953 * Release a PWM previously allocated using devm_pwm_get(). Calling this
954 * function is usually not needed because devm-allocated resources are
955 * automatically released on driver detach.
956 */
957void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
958{
959 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
960}
961EXPORT_SYMBOL_GPL(devm_pwm_put);
962
963/**
964 * pwm_can_sleep() - report whether PWM access will sleep
965 * @pwm: PWM device
966 *
967 * Returns: True if accessing the PWM can sleep, false otherwise.
968 */
969bool pwm_can_sleep(struct pwm_device *pwm)
970{
971 return true;
972}
973EXPORT_SYMBOL_GPL(pwm_can_sleep);
974
975#ifdef CONFIG_DEBUG_FS
976static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
977{
978 unsigned int i;
979
980 for (i = 0; i < chip->npwm; i++) {
981 struct pwm_device *pwm = &chip->pwms[i];
982 struct pwm_state state;
983
984 pwm_get_state(pwm, &state);
985
986 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
987
988 if (test_bit(PWMF_REQUESTED, &pwm->flags))
989 seq_puts(s, " requested");
990
991 if (state.enabled)
992 seq_puts(s, " enabled");
993
994 seq_printf(s, " period: %u ns", state.period);
995 seq_printf(s, " duty: %u ns", state.duty_cycle);
996 seq_printf(s, " polarity: %s",
997 state.polarity ? "inverse" : "normal");
998
999 seq_puts(s, "\n");
1000 }
1001}
1002
1003static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1004{
1005 mutex_lock(&pwm_lock);
1006 s->private = "";
1007
1008 return seq_list_start(&pwm_chips, *pos);
1009}
1010
1011static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1012{
1013 s->private = "\n";
1014
1015 return seq_list_next(v, &pwm_chips, pos);
1016}
1017
1018static void pwm_seq_stop(struct seq_file *s, void *v)
1019{
1020 mutex_unlock(&pwm_lock);
1021}
1022
1023static int pwm_seq_show(struct seq_file *s, void *v)
1024{
1025 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1026
1027 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1028 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1029 dev_name(chip->dev), chip->npwm,
1030 (chip->npwm != 1) ? "s" : "");
1031
1032 if (chip->ops->dbg_show)
1033 chip->ops->dbg_show(chip, s);
1034 else
1035 pwm_dbg_show(chip, s);
1036
1037 return 0;
1038}
1039
1040static const struct seq_operations pwm_seq_ops = {
1041 .start = pwm_seq_start,
1042 .next = pwm_seq_next,
1043 .stop = pwm_seq_stop,
1044 .show = pwm_seq_show,
1045};
1046
1047static int pwm_seq_open(struct inode *inode, struct file *file)
1048{
1049 return seq_open(file, &pwm_seq_ops);
1050}
1051
1052static const struct file_operations pwm_debugfs_ops = {
1053 .owner = THIS_MODULE,
1054 .open = pwm_seq_open,
1055 .read = seq_read,
1056 .llseek = seq_lseek,
1057 .release = seq_release,
1058};
1059
1060static int __init pwm_debugfs_init(void)
1061{
1062 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1063 &pwm_debugfs_ops);
1064
1065 return 0;
1066}
1067subsys_initcall(pwm_debugfs_init);
1068#endif /* CONFIG_DEBUG_FS */