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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 /* check, whether the driver supports a third cell for flags */
141 if (pc->of_pwm_n_cells < 3)
142 return ERR_PTR(-EINVAL);
143
144 /* flags in the third cell are optional */
145 if (args->args_count < 2)
146 return ERR_PTR(-EINVAL);
147
148 if (args->args[0] >= pc->npwm)
149 return ERR_PTR(-EINVAL);
150
151 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
152 if (IS_ERR(pwm))
153 return pwm;
154
155 pwm->args.period = args->args[1];
156 pwm->args.polarity = PWM_POLARITY_NORMAL;
157
158 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
159 pwm->args.polarity = PWM_POLARITY_INVERSED;
160
161 return pwm;
162}
163EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
164
165static struct pwm_device *
166of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
167{
168 struct pwm_device *pwm;
169
170 /* sanity check driver support */
171 if (pc->of_pwm_n_cells < 2)
172 return ERR_PTR(-EINVAL);
173
174 /* all cells are required */
175 if (args->args_count != pc->of_pwm_n_cells)
176 return ERR_PTR(-EINVAL);
177
178 if (args->args[0] >= pc->npwm)
179 return ERR_PTR(-EINVAL);
180
181 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
182 if (IS_ERR(pwm))
183 return pwm;
184
185 pwm->args.period = args->args[1];
186
187 return pwm;
188}
189
190static void of_pwmchip_add(struct pwm_chip *chip)
191{
192 if (!chip->dev || !chip->dev->of_node)
193 return;
194
195 if (!chip->of_xlate) {
196 chip->of_xlate = of_pwm_simple_xlate;
197 chip->of_pwm_n_cells = 2;
198 }
199
200 of_node_get(chip->dev->of_node);
201}
202
203static void of_pwmchip_remove(struct pwm_chip *chip)
204{
205 if (chip->dev)
206 of_node_put(chip->dev->of_node);
207}
208
209/**
210 * pwm_set_chip_data() - set private chip data for a PWM
211 * @pwm: PWM device
212 * @data: pointer to chip-specific data
213 *
214 * Returns: 0 on success or a negative error code on failure.
215 */
216int pwm_set_chip_data(struct pwm_device *pwm, void *data)
217{
218 if (!pwm)
219 return -EINVAL;
220
221 pwm->chip_data = data;
222
223 return 0;
224}
225EXPORT_SYMBOL_GPL(pwm_set_chip_data);
226
227/**
228 * pwm_get_chip_data() - get private chip data for a PWM
229 * @pwm: PWM device
230 *
231 * Returns: A pointer to the chip-private data for the PWM device.
232 */
233void *pwm_get_chip_data(struct pwm_device *pwm)
234{
235 return pwm ? pwm->chip_data : NULL;
236}
237EXPORT_SYMBOL_GPL(pwm_get_chip_data);
238
239static bool pwm_ops_check(const struct pwm_ops *ops)
240{
241 /* driver supports legacy, non-atomic operation */
242 if (ops->config && ops->enable && ops->disable)
243 return true;
244
245 /* driver supports atomic operation */
246 if (ops->apply)
247 return true;
248
249 return false;
250}
251
252/**
253 * pwmchip_add_with_polarity() - register a new PWM chip
254 * @chip: the PWM chip to add
255 * @polarity: initial polarity of PWM channels
256 *
257 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
258 * will be used. The initial polarity for all channels is specified by the
259 * @polarity parameter.
260 *
261 * Returns: 0 on success or a negative error code on failure.
262 */
263int pwmchip_add_with_polarity(struct pwm_chip *chip,
264 enum pwm_polarity polarity)
265{
266 struct pwm_device *pwm;
267 unsigned int i;
268 int ret;
269
270 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
271 return -EINVAL;
272
273 if (!pwm_ops_check(chip->ops))
274 return -EINVAL;
275
276 mutex_lock(&pwm_lock);
277
278 ret = alloc_pwms(chip->base, chip->npwm);
279 if (ret < 0)
280 goto out;
281
282 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
283 if (!chip->pwms) {
284 ret = -ENOMEM;
285 goto out;
286 }
287
288 chip->base = ret;
289
290 for (i = 0; i < chip->npwm; i++) {
291 pwm = &chip->pwms[i];
292
293 pwm->chip = chip;
294 pwm->pwm = chip->base + i;
295 pwm->hwpwm = i;
296 pwm->state.polarity = polarity;
297
298 if (chip->ops->get_state)
299 chip->ops->get_state(chip, pwm, &pwm->state);
300
301 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
302 }
303
304 bitmap_set(allocated_pwms, chip->base, chip->npwm);
305
306 INIT_LIST_HEAD(&chip->list);
307 list_add(&chip->list, &pwm_chips);
308
309 ret = 0;
310
311 if (IS_ENABLED(CONFIG_OF))
312 of_pwmchip_add(chip);
313
314 pwmchip_sysfs_export(chip);
315
316out:
317 mutex_unlock(&pwm_lock);
318 return ret;
319}
320EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
321
322/**
323 * pwmchip_add() - register a new PWM chip
324 * @chip: the PWM chip to add
325 *
326 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
327 * will be used. The initial polarity for all channels is normal.
328 *
329 * Returns: 0 on success or a negative error code on failure.
330 */
331int pwmchip_add(struct pwm_chip *chip)
332{
333 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
334}
335EXPORT_SYMBOL_GPL(pwmchip_add);
336
337/**
338 * pwmchip_remove() - remove a PWM chip
339 * @chip: the PWM chip to remove
340 *
341 * Removes a PWM chip. This function may return busy if the PWM chip provides
342 * a PWM device that is still requested.
343 *
344 * Returns: 0 on success or a negative error code on failure.
345 */
346int pwmchip_remove(struct pwm_chip *chip)
347{
348 unsigned int i;
349 int ret = 0;
350
351 pwmchip_sysfs_unexport_children(chip);
352
353 mutex_lock(&pwm_lock);
354
355 for (i = 0; i < chip->npwm; i++) {
356 struct pwm_device *pwm = &chip->pwms[i];
357
358 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
359 ret = -EBUSY;
360 goto out;
361 }
362 }
363
364 list_del_init(&chip->list);
365
366 if (IS_ENABLED(CONFIG_OF))
367 of_pwmchip_remove(chip);
368
369 free_pwms(chip);
370
371 pwmchip_sysfs_unexport(chip);
372
373out:
374 mutex_unlock(&pwm_lock);
375 return ret;
376}
377EXPORT_SYMBOL_GPL(pwmchip_remove);
378
379/**
380 * pwm_request() - request a PWM device
381 * @pwm: global PWM device index
382 * @label: PWM device label
383 *
384 * This function is deprecated, use pwm_get() instead.
385 *
386 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
387 * failure.
388 */
389struct pwm_device *pwm_request(int pwm, const char *label)
390{
391 struct pwm_device *dev;
392 int err;
393
394 if (pwm < 0 || pwm >= MAX_PWMS)
395 return ERR_PTR(-EINVAL);
396
397 mutex_lock(&pwm_lock);
398
399 dev = pwm_to_device(pwm);
400 if (!dev) {
401 dev = ERR_PTR(-EPROBE_DEFER);
402 goto out;
403 }
404
405 err = pwm_device_request(dev, label);
406 if (err < 0)
407 dev = ERR_PTR(err);
408
409out:
410 mutex_unlock(&pwm_lock);
411
412 return dev;
413}
414EXPORT_SYMBOL_GPL(pwm_request);
415
416/**
417 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
418 * @chip: PWM chip
419 * @index: per-chip index of the PWM to request
420 * @label: a literal description string of this PWM
421 *
422 * Returns: A pointer to the PWM device at the given index of the given PWM
423 * chip. A negative error code is returned if the index is not valid for the
424 * specified PWM chip or if the PWM device cannot be requested.
425 */
426struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
427 unsigned int index,
428 const char *label)
429{
430 struct pwm_device *pwm;
431 int err;
432
433 if (!chip || index >= chip->npwm)
434 return ERR_PTR(-EINVAL);
435
436 mutex_lock(&pwm_lock);
437 pwm = &chip->pwms[index];
438
439 err = pwm_device_request(pwm, label);
440 if (err < 0)
441 pwm = ERR_PTR(err);
442
443 mutex_unlock(&pwm_lock);
444 return pwm;
445}
446EXPORT_SYMBOL_GPL(pwm_request_from_chip);
447
448/**
449 * pwm_free() - free a PWM device
450 * @pwm: PWM device
451 *
452 * This function is deprecated, use pwm_put() instead.
453 */
454void pwm_free(struct pwm_device *pwm)
455{
456 pwm_put(pwm);
457}
458EXPORT_SYMBOL_GPL(pwm_free);
459
460/**
461 * pwm_apply_state() - atomically apply a new state to a PWM device
462 * @pwm: PWM device
463 * @state: new state to apply. This can be adjusted by the PWM driver
464 * if the requested config is not achievable, for example,
465 * ->duty_cycle and ->period might be approximated.
466 */
467int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
468{
469 int err;
470
471 if (!pwm || !state || !state->period ||
472 state->duty_cycle > state->period)
473 return -EINVAL;
474
475 if (!memcmp(state, &pwm->state, sizeof(*state)))
476 return 0;
477
478 if (pwm->chip->ops->apply) {
479 err = pwm->chip->ops->apply(pwm->chip, pwm, state);
480 if (err)
481 return err;
482
483 pwm->state = *state;
484 } else {
485 /*
486 * FIXME: restore the initial state in case of error.
487 */
488 if (state->polarity != pwm->state.polarity) {
489 if (!pwm->chip->ops->set_polarity)
490 return -ENOTSUPP;
491
492 /*
493 * Changing the polarity of a running PWM is
494 * only allowed when the PWM driver implements
495 * ->apply().
496 */
497 if (pwm->state.enabled) {
498 pwm->chip->ops->disable(pwm->chip, pwm);
499 pwm->state.enabled = false;
500 }
501
502 err = pwm->chip->ops->set_polarity(pwm->chip, pwm,
503 state->polarity);
504 if (err)
505 return err;
506
507 pwm->state.polarity = state->polarity;
508 }
509
510 if (state->period != pwm->state.period ||
511 state->duty_cycle != pwm->state.duty_cycle) {
512 err = pwm->chip->ops->config(pwm->chip, pwm,
513 state->duty_cycle,
514 state->period);
515 if (err)
516 return err;
517
518 pwm->state.duty_cycle = state->duty_cycle;
519 pwm->state.period = state->period;
520 }
521
522 if (state->enabled != pwm->state.enabled) {
523 if (state->enabled) {
524 err = pwm->chip->ops->enable(pwm->chip, pwm);
525 if (err)
526 return err;
527 } else {
528 pwm->chip->ops->disable(pwm->chip, pwm);
529 }
530
531 pwm->state.enabled = state->enabled;
532 }
533 }
534
535 return 0;
536}
537EXPORT_SYMBOL_GPL(pwm_apply_state);
538
539/**
540 * pwm_capture() - capture and report a PWM signal
541 * @pwm: PWM device
542 * @result: structure to fill with capture result
543 * @timeout: time to wait, in milliseconds, before giving up on capture
544 *
545 * Returns: 0 on success or a negative error code on failure.
546 */
547int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
548 unsigned long timeout)
549{
550 int err;
551
552 if (!pwm || !pwm->chip->ops)
553 return -EINVAL;
554
555 if (!pwm->chip->ops->capture)
556 return -ENOSYS;
557
558 mutex_lock(&pwm_lock);
559 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
560 mutex_unlock(&pwm_lock);
561
562 return err;
563}
564EXPORT_SYMBOL_GPL(pwm_capture);
565
566/**
567 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
568 * @pwm: PWM device
569 *
570 * This function will adjust the PWM config to the PWM arguments provided
571 * by the DT or PWM lookup table. This is particularly useful to adapt
572 * the bootloader config to the Linux one.
573 */
574int pwm_adjust_config(struct pwm_device *pwm)
575{
576 struct pwm_state state;
577 struct pwm_args pargs;
578
579 pwm_get_args(pwm, &pargs);
580 pwm_get_state(pwm, &state);
581
582 /*
583 * If the current period is zero it means that either the PWM driver
584 * does not support initial state retrieval or the PWM has not yet
585 * been configured.
586 *
587 * In either case, we setup the new period and polarity, and assign a
588 * duty cycle of 0.
589 */
590 if (!state.period) {
591 state.duty_cycle = 0;
592 state.period = pargs.period;
593 state.polarity = pargs.polarity;
594
595 return pwm_apply_state(pwm, &state);
596 }
597
598 /*
599 * Adjust the PWM duty cycle/period based on the period value provided
600 * in PWM args.
601 */
602 if (pargs.period != state.period) {
603 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
604
605 do_div(dutycycle, state.period);
606 state.duty_cycle = dutycycle;
607 state.period = pargs.period;
608 }
609
610 /*
611 * If the polarity changed, we should also change the duty cycle.
612 */
613 if (pargs.polarity != state.polarity) {
614 state.polarity = pargs.polarity;
615 state.duty_cycle = state.period - state.duty_cycle;
616 }
617
618 return pwm_apply_state(pwm, &state);
619}
620EXPORT_SYMBOL_GPL(pwm_adjust_config);
621
622static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
623{
624 struct pwm_chip *chip;
625
626 mutex_lock(&pwm_lock);
627
628 list_for_each_entry(chip, &pwm_chips, list)
629 if (chip->dev && chip->dev->of_node == np) {
630 mutex_unlock(&pwm_lock);
631 return chip;
632 }
633
634 mutex_unlock(&pwm_lock);
635
636 return ERR_PTR(-EPROBE_DEFER);
637}
638
639/**
640 * of_pwm_get() - request a PWM via the PWM framework
641 * @np: device node to get the PWM from
642 * @con_id: consumer name
643 *
644 * Returns the PWM device parsed from the phandle and index specified in the
645 * "pwms" property of a device tree node or a negative error-code on failure.
646 * Values parsed from the device tree are stored in the returned PWM device
647 * object.
648 *
649 * If con_id is NULL, the first PWM device listed in the "pwms" property will
650 * be requested. Otherwise the "pwm-names" property is used to do a reverse
651 * lookup of the PWM index. This also means that the "pwm-names" property
652 * becomes mandatory for devices that look up the PWM device via the con_id
653 * parameter.
654 *
655 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
656 * error code on failure.
657 */
658struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
659{
660 struct pwm_device *pwm = NULL;
661 struct of_phandle_args args;
662 struct pwm_chip *pc;
663 int index = 0;
664 int err;
665
666 if (con_id) {
667 index = of_property_match_string(np, "pwm-names", con_id);
668 if (index < 0)
669 return ERR_PTR(index);
670 }
671
672 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
673 &args);
674 if (err) {
675 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
676 return ERR_PTR(err);
677 }
678
679 pc = of_node_to_pwmchip(args.np);
680 if (IS_ERR(pc)) {
681 if (PTR_ERR(pc) != -EPROBE_DEFER)
682 pr_err("%s(): PWM chip not found\n", __func__);
683
684 pwm = ERR_CAST(pc);
685 goto put;
686 }
687
688 pwm = pc->of_xlate(pc, &args);
689 if (IS_ERR(pwm))
690 goto put;
691
692 /*
693 * If a consumer name was not given, try to look it up from the
694 * "pwm-names" property if it exists. Otherwise use the name of
695 * the user device node.
696 */
697 if (!con_id) {
698 err = of_property_read_string_index(np, "pwm-names", index,
699 &con_id);
700 if (err < 0)
701 con_id = np->name;
702 }
703
704 pwm->label = con_id;
705
706put:
707 of_node_put(args.np);
708
709 return pwm;
710}
711EXPORT_SYMBOL_GPL(of_pwm_get);
712
713/**
714 * pwm_add_table() - register PWM device consumers
715 * @table: array of consumers to register
716 * @num: number of consumers in table
717 */
718void pwm_add_table(struct pwm_lookup *table, size_t num)
719{
720 mutex_lock(&pwm_lookup_lock);
721
722 while (num--) {
723 list_add_tail(&table->list, &pwm_lookup_list);
724 table++;
725 }
726
727 mutex_unlock(&pwm_lookup_lock);
728}
729
730/**
731 * pwm_remove_table() - unregister PWM device consumers
732 * @table: array of consumers to unregister
733 * @num: number of consumers in table
734 */
735void pwm_remove_table(struct pwm_lookup *table, size_t num)
736{
737 mutex_lock(&pwm_lookup_lock);
738
739 while (num--) {
740 list_del(&table->list);
741 table++;
742 }
743
744 mutex_unlock(&pwm_lookup_lock);
745}
746
747/**
748 * pwm_get() - look up and request a PWM device
749 * @dev: device for PWM consumer
750 * @con_id: consumer name
751 *
752 * Lookup is first attempted using DT. If the device was not instantiated from
753 * a device tree, a PWM chip and a relative index is looked up via a table
754 * supplied by board setup code (see pwm_add_table()).
755 *
756 * Once a PWM chip has been found the specified PWM device will be requested
757 * and is ready to be used.
758 *
759 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
760 * error code on failure.
761 */
762struct pwm_device *pwm_get(struct device *dev, const char *con_id)
763{
764 const char *dev_id = dev ? dev_name(dev) : NULL;
765 struct pwm_device *pwm;
766 struct pwm_chip *chip;
767 unsigned int best = 0;
768 struct pwm_lookup *p, *chosen = NULL;
769 unsigned int match;
770 int err;
771
772 /* look up via DT first */
773 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
774 return of_pwm_get(dev->of_node, con_id);
775
776 /*
777 * We look up the provider in the static table typically provided by
778 * board setup code. We first try to lookup the consumer device by
779 * name. If the consumer device was passed in as NULL or if no match
780 * was found, we try to find the consumer by directly looking it up
781 * by name.
782 *
783 * If a match is found, the provider PWM chip is looked up by name
784 * and a PWM device is requested using the PWM device per-chip index.
785 *
786 * The lookup algorithm was shamelessly taken from the clock
787 * framework:
788 *
789 * We do slightly fuzzy matching here:
790 * An entry with a NULL ID is assumed to be a wildcard.
791 * If an entry has a device ID, it must match
792 * If an entry has a connection ID, it must match
793 * Then we take the most specific entry - with the following order
794 * of precedence: dev+con > dev only > con only.
795 */
796 mutex_lock(&pwm_lookup_lock);
797
798 list_for_each_entry(p, &pwm_lookup_list, list) {
799 match = 0;
800
801 if (p->dev_id) {
802 if (!dev_id || strcmp(p->dev_id, dev_id))
803 continue;
804
805 match += 2;
806 }
807
808 if (p->con_id) {
809 if (!con_id || strcmp(p->con_id, con_id))
810 continue;
811
812 match += 1;
813 }
814
815 if (match > best) {
816 chosen = p;
817
818 if (match != 3)
819 best = match;
820 else
821 break;
822 }
823 }
824
825 mutex_unlock(&pwm_lookup_lock);
826
827 if (!chosen)
828 return ERR_PTR(-ENODEV);
829
830 chip = pwmchip_find_by_name(chosen->provider);
831
832 /*
833 * If the lookup entry specifies a module, load the module and retry
834 * the PWM chip lookup. This can be used to work around driver load
835 * ordering issues if driver's can't be made to properly support the
836 * deferred probe mechanism.
837 */
838 if (!chip && chosen->module) {
839 err = request_module(chosen->module);
840 if (err == 0)
841 chip = pwmchip_find_by_name(chosen->provider);
842 }
843
844 if (!chip)
845 return ERR_PTR(-EPROBE_DEFER);
846
847 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
848 if (IS_ERR(pwm))
849 return pwm;
850
851 pwm->args.period = chosen->period;
852 pwm->args.polarity = chosen->polarity;
853
854 return pwm;
855}
856EXPORT_SYMBOL_GPL(pwm_get);
857
858/**
859 * pwm_put() - release a PWM device
860 * @pwm: PWM device
861 */
862void pwm_put(struct pwm_device *pwm)
863{
864 if (!pwm)
865 return;
866
867 mutex_lock(&pwm_lock);
868
869 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
870 pr_warn("PWM device already freed\n");
871 goto out;
872 }
873
874 if (pwm->chip->ops->free)
875 pwm->chip->ops->free(pwm->chip, pwm);
876
877 pwm->label = NULL;
878
879 module_put(pwm->chip->ops->owner);
880out:
881 mutex_unlock(&pwm_lock);
882}
883EXPORT_SYMBOL_GPL(pwm_put);
884
885static void devm_pwm_release(struct device *dev, void *res)
886{
887 pwm_put(*(struct pwm_device **)res);
888}
889
890/**
891 * devm_pwm_get() - resource managed pwm_get()
892 * @dev: device for PWM consumer
893 * @con_id: consumer name
894 *
895 * This function performs like pwm_get() but the acquired PWM device will
896 * automatically be released on driver detach.
897 *
898 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
899 * error code on failure.
900 */
901struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
902{
903 struct pwm_device **ptr, *pwm;
904
905 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
906 if (!ptr)
907 return ERR_PTR(-ENOMEM);
908
909 pwm = pwm_get(dev, con_id);
910 if (!IS_ERR(pwm)) {
911 *ptr = pwm;
912 devres_add(dev, ptr);
913 } else {
914 devres_free(ptr);
915 }
916
917 return pwm;
918}
919EXPORT_SYMBOL_GPL(devm_pwm_get);
920
921/**
922 * devm_of_pwm_get() - resource managed of_pwm_get()
923 * @dev: device for PWM consumer
924 * @np: device node to get the PWM from
925 * @con_id: consumer name
926 *
927 * This function performs like of_pwm_get() but the acquired PWM device will
928 * automatically be released on driver detach.
929 *
930 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
931 * error code on failure.
932 */
933struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
934 const char *con_id)
935{
936 struct pwm_device **ptr, *pwm;
937
938 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
939 if (!ptr)
940 return ERR_PTR(-ENOMEM);
941
942 pwm = of_pwm_get(np, con_id);
943 if (!IS_ERR(pwm)) {
944 *ptr = pwm;
945 devres_add(dev, ptr);
946 } else {
947 devres_free(ptr);
948 }
949
950 return pwm;
951}
952EXPORT_SYMBOL_GPL(devm_of_pwm_get);
953
954static int devm_pwm_match(struct device *dev, void *res, void *data)
955{
956 struct pwm_device **p = res;
957
958 if (WARN_ON(!p || !*p))
959 return 0;
960
961 return *p == data;
962}
963
964/**
965 * devm_pwm_put() - resource managed pwm_put()
966 * @dev: device for PWM consumer
967 * @pwm: PWM device
968 *
969 * Release a PWM previously allocated using devm_pwm_get(). Calling this
970 * function is usually not needed because devm-allocated resources are
971 * automatically released on driver detach.
972 */
973void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
974{
975 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
976}
977EXPORT_SYMBOL_GPL(devm_pwm_put);
978
979#ifdef CONFIG_DEBUG_FS
980static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
981{
982 unsigned int i;
983
984 for (i = 0; i < chip->npwm; i++) {
985 struct pwm_device *pwm = &chip->pwms[i];
986 struct pwm_state state;
987
988 pwm_get_state(pwm, &state);
989
990 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
991
992 if (test_bit(PWMF_REQUESTED, &pwm->flags))
993 seq_puts(s, " requested");
994
995 if (state.enabled)
996 seq_puts(s, " enabled");
997
998 seq_printf(s, " period: %u ns", state.period);
999 seq_printf(s, " duty: %u ns", state.duty_cycle);
1000 seq_printf(s, " polarity: %s",
1001 state.polarity ? "inverse" : "normal");
1002
1003 seq_puts(s, "\n");
1004 }
1005}
1006
1007static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1008{
1009 mutex_lock(&pwm_lock);
1010 s->private = "";
1011
1012 return seq_list_start(&pwm_chips, *pos);
1013}
1014
1015static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1016{
1017 s->private = "\n";
1018
1019 return seq_list_next(v, &pwm_chips, pos);
1020}
1021
1022static void pwm_seq_stop(struct seq_file *s, void *v)
1023{
1024 mutex_unlock(&pwm_lock);
1025}
1026
1027static int pwm_seq_show(struct seq_file *s, void *v)
1028{
1029 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1030
1031 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1032 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1033 dev_name(chip->dev), chip->npwm,
1034 (chip->npwm != 1) ? "s" : "");
1035
1036 if (chip->ops->dbg_show)
1037 chip->ops->dbg_show(chip, s);
1038 else
1039 pwm_dbg_show(chip, s);
1040
1041 return 0;
1042}
1043
1044static const struct seq_operations pwm_seq_ops = {
1045 .start = pwm_seq_start,
1046 .next = pwm_seq_next,
1047 .stop = pwm_seq_stop,
1048 .show = pwm_seq_show,
1049};
1050
1051static int pwm_seq_open(struct inode *inode, struct file *file)
1052{
1053 return seq_open(file, &pwm_seq_ops);
1054}
1055
1056static const struct file_operations pwm_debugfs_ops = {
1057 .owner = THIS_MODULE,
1058 .open = pwm_seq_open,
1059 .read = seq_read,
1060 .llseek = seq_lseek,
1061 .release = seq_release,
1062};
1063
1064static int __init pwm_debugfs_init(void)
1065{
1066 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1067 &pwm_debugfs_ops);
1068
1069 return 0;
1070}
1071subsys_initcall(pwm_debugfs_init);
1072#endif /* CONFIG_DEBUG_FS */