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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic pwmlib implementation
4 *
5 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
6 * Copyright (C) 2011-2012 Avionic Design GmbH
7 */
8
9#include <linux/acpi.h>
10#include <linux/module.h>
11#include <linux/pwm.h>
12#include <linux/radix-tree.h>
13#include <linux/list.h>
14#include <linux/mutex.h>
15#include <linux/err.h>
16#include <linux/slab.h>
17#include <linux/device.h>
18#include <linux/debugfs.h>
19#include <linux/seq_file.h>
20
21#include <dt-bindings/pwm/pwm.h>
22
23#define CREATE_TRACE_POINTS
24#include <trace/events/pwm.h>
25
26#define MAX_PWMS 1024
27
28static DEFINE_MUTEX(pwm_lookup_lock);
29static LIST_HEAD(pwm_lookup_list);
30
31/* protects access to pwm_chips, allocated_pwms, and pwm_tree */
32static DEFINE_MUTEX(pwm_lock);
33
34static LIST_HEAD(pwm_chips);
35static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
36static RADIX_TREE(pwm_tree, GFP_KERNEL);
37
38static struct pwm_device *pwm_to_device(unsigned int pwm)
39{
40 return radix_tree_lookup(&pwm_tree, pwm);
41}
42
43/* Called with pwm_lock held */
44static int alloc_pwms(unsigned int count)
45{
46 unsigned int start;
47
48 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, 0,
49 count, 0);
50
51 if (start + count > MAX_PWMS)
52 return -ENOSPC;
53
54 bitmap_set(allocated_pwms, start, count);
55
56 return start;
57}
58
59/* Called with pwm_lock held */
60static void free_pwms(struct pwm_chip *chip)
61{
62 unsigned int i;
63
64 for (i = 0; i < chip->npwm; i++) {
65 struct pwm_device *pwm = &chip->pwms[i];
66
67 radix_tree_delete(&pwm_tree, pwm->pwm);
68 }
69
70 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
71
72 kfree(chip->pwms);
73 chip->pwms = NULL;
74}
75
76static struct pwm_chip *pwmchip_find_by_name(const char *name)
77{
78 struct pwm_chip *chip;
79
80 if (!name)
81 return NULL;
82
83 mutex_lock(&pwm_lock);
84
85 list_for_each_entry(chip, &pwm_chips, list) {
86 const char *chip_name = dev_name(chip->dev);
87
88 if (chip_name && strcmp(chip_name, name) == 0) {
89 mutex_unlock(&pwm_lock);
90 return chip;
91 }
92 }
93
94 mutex_unlock(&pwm_lock);
95
96 return NULL;
97}
98
99static int pwm_device_request(struct pwm_device *pwm, const char *label)
100{
101 int err;
102
103 if (test_bit(PWMF_REQUESTED, &pwm->flags))
104 return -EBUSY;
105
106 if (!try_module_get(pwm->chip->ops->owner))
107 return -ENODEV;
108
109 if (pwm->chip->ops->request) {
110 err = pwm->chip->ops->request(pwm->chip, pwm);
111 if (err) {
112 module_put(pwm->chip->ops->owner);
113 return err;
114 }
115 }
116
117 if (pwm->chip->ops->get_state) {
118 struct pwm_state state;
119
120 err = pwm->chip->ops->get_state(pwm->chip, pwm, &state);
121 trace_pwm_get(pwm, &state, err);
122
123 if (!err)
124 pwm->state = state;
125
126 if (IS_ENABLED(CONFIG_PWM_DEBUG))
127 pwm->last = pwm->state;
128 }
129
130 set_bit(PWMF_REQUESTED, &pwm->flags);
131 pwm->label = label;
132
133 return 0;
134}
135
136struct pwm_device *
137of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
138{
139 struct pwm_device *pwm;
140
141 if (pc->of_pwm_n_cells < 2)
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 (pc->of_pwm_n_cells >= 3) {
159 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
160 pwm->args.polarity = PWM_POLARITY_INVERSED;
161 }
162
163 return pwm;
164}
165EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
166
167struct pwm_device *
168of_pwm_single_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
169{
170 struct pwm_device *pwm;
171
172 if (pc->of_pwm_n_cells < 1)
173 return ERR_PTR(-EINVAL);
174
175 /* validate that one cell is specified, optionally with flags */
176 if (args->args_count != 1 && args->args_count != 2)
177 return ERR_PTR(-EINVAL);
178
179 pwm = pwm_request_from_chip(pc, 0, NULL);
180 if (IS_ERR(pwm))
181 return pwm;
182
183 pwm->args.period = args->args[0];
184 pwm->args.polarity = PWM_POLARITY_NORMAL;
185
186 if (args->args_count == 2 && args->args[2] & PWM_POLARITY_INVERTED)
187 pwm->args.polarity = PWM_POLARITY_INVERSED;
188
189 return pwm;
190}
191EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
192
193static void of_pwmchip_add(struct pwm_chip *chip)
194{
195 if (!chip->dev || !chip->dev->of_node)
196 return;
197
198 if (!chip->of_xlate) {
199 u32 pwm_cells;
200
201 if (of_property_read_u32(chip->dev->of_node, "#pwm-cells",
202 &pwm_cells))
203 pwm_cells = 2;
204
205 chip->of_xlate = of_pwm_xlate_with_flags;
206 chip->of_pwm_n_cells = pwm_cells;
207 }
208
209 of_node_get(chip->dev->of_node);
210}
211
212static void of_pwmchip_remove(struct pwm_chip *chip)
213{
214 if (chip->dev)
215 of_node_put(chip->dev->of_node);
216}
217
218/**
219 * pwm_set_chip_data() - set private chip data for a PWM
220 * @pwm: PWM device
221 * @data: pointer to chip-specific data
222 *
223 * Returns: 0 on success or a negative error code on failure.
224 */
225int pwm_set_chip_data(struct pwm_device *pwm, void *data)
226{
227 if (!pwm)
228 return -EINVAL;
229
230 pwm->chip_data = data;
231
232 return 0;
233}
234EXPORT_SYMBOL_GPL(pwm_set_chip_data);
235
236/**
237 * pwm_get_chip_data() - get private chip data for a PWM
238 * @pwm: PWM device
239 *
240 * Returns: A pointer to the chip-private data for the PWM device.
241 */
242void *pwm_get_chip_data(struct pwm_device *pwm)
243{
244 return pwm ? pwm->chip_data : NULL;
245}
246EXPORT_SYMBOL_GPL(pwm_get_chip_data);
247
248static bool pwm_ops_check(const struct pwm_chip *chip)
249{
250 const struct pwm_ops *ops = chip->ops;
251
252 if (!ops->apply)
253 return false;
254
255 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
256 dev_warn(chip->dev,
257 "Please implement the .get_state() callback\n");
258
259 return true;
260}
261
262/**
263 * pwmchip_add() - register a new PWM chip
264 * @chip: the PWM chip to add
265 *
266 * Register a new PWM chip.
267 *
268 * Returns: 0 on success or a negative error code on failure.
269 */
270int pwmchip_add(struct pwm_chip *chip)
271{
272 struct pwm_device *pwm;
273 unsigned int i;
274 int ret;
275
276 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
277 return -EINVAL;
278
279 if (!pwm_ops_check(chip))
280 return -EINVAL;
281
282 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
283 if (!chip->pwms)
284 return -ENOMEM;
285
286 mutex_lock(&pwm_lock);
287
288 ret = alloc_pwms(chip->npwm);
289 if (ret < 0) {
290 mutex_unlock(&pwm_lock);
291 kfree(chip->pwms);
292 return ret;
293 }
294
295 chip->base = ret;
296
297 for (i = 0; i < chip->npwm; i++) {
298 pwm = &chip->pwms[i];
299
300 pwm->chip = chip;
301 pwm->pwm = chip->base + i;
302 pwm->hwpwm = i;
303
304 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
305 }
306
307 list_add(&chip->list, &pwm_chips);
308
309 mutex_unlock(&pwm_lock);
310
311 if (IS_ENABLED(CONFIG_OF))
312 of_pwmchip_add(chip);
313
314 pwmchip_sysfs_export(chip);
315
316 return 0;
317}
318EXPORT_SYMBOL_GPL(pwmchip_add);
319
320/**
321 * pwmchip_remove() - remove a PWM chip
322 * @chip: the PWM chip to remove
323 *
324 * Removes a PWM chip. This function may return busy if the PWM chip provides
325 * a PWM device that is still requested.
326 *
327 * Returns: 0 on success or a negative error code on failure.
328 */
329void pwmchip_remove(struct pwm_chip *chip)
330{
331 pwmchip_sysfs_unexport(chip);
332
333 mutex_lock(&pwm_lock);
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 mutex_unlock(&pwm_lock);
343}
344EXPORT_SYMBOL_GPL(pwmchip_remove);
345
346static void devm_pwmchip_remove(void *data)
347{
348 struct pwm_chip *chip = data;
349
350 pwmchip_remove(chip);
351}
352
353int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip)
354{
355 int ret;
356
357 ret = pwmchip_add(chip);
358 if (ret)
359 return ret;
360
361 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
362}
363EXPORT_SYMBOL_GPL(devm_pwmchip_add);
364
365/**
366 * pwm_request() - request a PWM device
367 * @pwm: global PWM device index
368 * @label: PWM device label
369 *
370 * This function is deprecated, use pwm_get() instead.
371 *
372 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
373 * failure.
374 */
375struct pwm_device *pwm_request(int pwm, const char *label)
376{
377 struct pwm_device *dev;
378 int err;
379
380 if (pwm < 0 || pwm >= MAX_PWMS)
381 return ERR_PTR(-EINVAL);
382
383 mutex_lock(&pwm_lock);
384
385 dev = pwm_to_device(pwm);
386 if (!dev) {
387 dev = ERR_PTR(-EPROBE_DEFER);
388 goto out;
389 }
390
391 err = pwm_device_request(dev, label);
392 if (err < 0)
393 dev = ERR_PTR(err);
394
395out:
396 mutex_unlock(&pwm_lock);
397
398 return dev;
399}
400EXPORT_SYMBOL_GPL(pwm_request);
401
402/**
403 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
404 * @chip: PWM chip
405 * @index: per-chip index of the PWM to request
406 * @label: a literal description string of this PWM
407 *
408 * Returns: A pointer to the PWM device at the given index of the given PWM
409 * chip. A negative error code is returned if the index is not valid for the
410 * specified PWM chip or if the PWM device cannot be requested.
411 */
412struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
413 unsigned int index,
414 const char *label)
415{
416 struct pwm_device *pwm;
417 int err;
418
419 if (!chip || index >= chip->npwm)
420 return ERR_PTR(-EINVAL);
421
422 mutex_lock(&pwm_lock);
423 pwm = &chip->pwms[index];
424
425 err = pwm_device_request(pwm, label);
426 if (err < 0)
427 pwm = ERR_PTR(err);
428
429 mutex_unlock(&pwm_lock);
430 return pwm;
431}
432EXPORT_SYMBOL_GPL(pwm_request_from_chip);
433
434/**
435 * pwm_free() - free a PWM device
436 * @pwm: PWM device
437 *
438 * This function is deprecated, use pwm_put() instead.
439 */
440void pwm_free(struct pwm_device *pwm)
441{
442 pwm_put(pwm);
443}
444EXPORT_SYMBOL_GPL(pwm_free);
445
446static void pwm_apply_state_debug(struct pwm_device *pwm,
447 const struct pwm_state *state)
448{
449 struct pwm_state *last = &pwm->last;
450 struct pwm_chip *chip = pwm->chip;
451 struct pwm_state s1, s2;
452 int err;
453
454 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
455 return;
456
457 /* No reasonable diagnosis possible without .get_state() */
458 if (!chip->ops->get_state)
459 return;
460
461 /*
462 * *state was just applied. Read out the hardware state and do some
463 * checks.
464 */
465
466 err = chip->ops->get_state(chip, pwm, &s1);
467 trace_pwm_get(pwm, &s1, err);
468 if (err)
469 /* If that failed there isn't much to debug */
470 return;
471
472 /*
473 * The lowlevel driver either ignored .polarity (which is a bug) or as
474 * best effort inverted .polarity and fixed .duty_cycle respectively.
475 * Undo this inversion and fixup for further tests.
476 */
477 if (s1.enabled && s1.polarity != state->polarity) {
478 s2.polarity = state->polarity;
479 s2.duty_cycle = s1.period - s1.duty_cycle;
480 s2.period = s1.period;
481 s2.enabled = s1.enabled;
482 } else {
483 s2 = s1;
484 }
485
486 if (s2.polarity != state->polarity &&
487 state->duty_cycle < state->period)
488 dev_warn(chip->dev, ".apply ignored .polarity\n");
489
490 if (state->enabled &&
491 last->polarity == state->polarity &&
492 last->period > s2.period &&
493 last->period <= state->period)
494 dev_warn(chip->dev,
495 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
496 state->period, s2.period, last->period);
497
498 if (state->enabled && state->period < s2.period)
499 dev_warn(chip->dev,
500 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
501 state->period, s2.period);
502
503 if (state->enabled &&
504 last->polarity == state->polarity &&
505 last->period == s2.period &&
506 last->duty_cycle > s2.duty_cycle &&
507 last->duty_cycle <= state->duty_cycle)
508 dev_warn(chip->dev,
509 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
510 state->duty_cycle, state->period,
511 s2.duty_cycle, s2.period,
512 last->duty_cycle, last->period);
513
514 if (state->enabled && state->duty_cycle < s2.duty_cycle)
515 dev_warn(chip->dev,
516 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
517 state->duty_cycle, state->period,
518 s2.duty_cycle, s2.period);
519
520 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
521 dev_warn(chip->dev,
522 "requested disabled, but yielded enabled with duty > 0\n");
523
524 /* reapply the state that the driver reported being configured. */
525 err = chip->ops->apply(chip, pwm, &s1);
526 trace_pwm_apply(pwm, &s1, err);
527 if (err) {
528 *last = s1;
529 dev_err(chip->dev, "failed to reapply current setting\n");
530 return;
531 }
532
533 err = chip->ops->get_state(chip, pwm, last);
534 trace_pwm_get(pwm, last, err);
535 if (err)
536 return;
537
538 /* reapplication of the current state should give an exact match */
539 if (s1.enabled != last->enabled ||
540 s1.polarity != last->polarity ||
541 (s1.enabled && s1.period != last->period) ||
542 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
543 dev_err(chip->dev,
544 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
545 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
546 last->enabled, last->polarity, last->duty_cycle,
547 last->period);
548 }
549}
550
551/**
552 * pwm_apply_state() - atomically apply a new state to a PWM device
553 * @pwm: PWM device
554 * @state: new state to apply
555 */
556int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
557{
558 struct pwm_chip *chip;
559 int err;
560
561 /*
562 * Some lowlevel driver's implementations of .apply() make use of
563 * mutexes, also with some drivers only returning when the new
564 * configuration is active calling pwm_apply_state() from atomic context
565 * is a bad idea. So make it explicit that calling this function might
566 * sleep.
567 */
568 might_sleep();
569
570 if (!pwm || !state || !state->period ||
571 state->duty_cycle > state->period)
572 return -EINVAL;
573
574 chip = pwm->chip;
575
576 if (state->period == pwm->state.period &&
577 state->duty_cycle == pwm->state.duty_cycle &&
578 state->polarity == pwm->state.polarity &&
579 state->enabled == pwm->state.enabled &&
580 state->usage_power == pwm->state.usage_power)
581 return 0;
582
583 err = chip->ops->apply(chip, pwm, state);
584 trace_pwm_apply(pwm, state, err);
585 if (err)
586 return err;
587
588 pwm->state = *state;
589
590 /*
591 * only do this after pwm->state was applied as some
592 * implementations of .get_state depend on this
593 */
594 pwm_apply_state_debug(pwm, state);
595
596 return 0;
597}
598EXPORT_SYMBOL_GPL(pwm_apply_state);
599
600/**
601 * pwm_capture() - capture and report a PWM signal
602 * @pwm: PWM device
603 * @result: structure to fill with capture result
604 * @timeout: time to wait, in milliseconds, before giving up on capture
605 *
606 * Returns: 0 on success or a negative error code on failure.
607 */
608int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
609 unsigned long timeout)
610{
611 int err;
612
613 if (!pwm || !pwm->chip->ops)
614 return -EINVAL;
615
616 if (!pwm->chip->ops->capture)
617 return -ENOSYS;
618
619 mutex_lock(&pwm_lock);
620 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
621 mutex_unlock(&pwm_lock);
622
623 return err;
624}
625EXPORT_SYMBOL_GPL(pwm_capture);
626
627/**
628 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
629 * @pwm: PWM device
630 *
631 * This function will adjust the PWM config to the PWM arguments provided
632 * by the DT or PWM lookup table. This is particularly useful to adapt
633 * the bootloader config to the Linux one.
634 */
635int pwm_adjust_config(struct pwm_device *pwm)
636{
637 struct pwm_state state;
638 struct pwm_args pargs;
639
640 pwm_get_args(pwm, &pargs);
641 pwm_get_state(pwm, &state);
642
643 /*
644 * If the current period is zero it means that either the PWM driver
645 * does not support initial state retrieval or the PWM has not yet
646 * been configured.
647 *
648 * In either case, we setup the new period and polarity, and assign a
649 * duty cycle of 0.
650 */
651 if (!state.period) {
652 state.duty_cycle = 0;
653 state.period = pargs.period;
654 state.polarity = pargs.polarity;
655
656 return pwm_apply_state(pwm, &state);
657 }
658
659 /*
660 * Adjust the PWM duty cycle/period based on the period value provided
661 * in PWM args.
662 */
663 if (pargs.period != state.period) {
664 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
665
666 do_div(dutycycle, state.period);
667 state.duty_cycle = dutycycle;
668 state.period = pargs.period;
669 }
670
671 /*
672 * If the polarity changed, we should also change the duty cycle.
673 */
674 if (pargs.polarity != state.polarity) {
675 state.polarity = pargs.polarity;
676 state.duty_cycle = state.period - state.duty_cycle;
677 }
678
679 return pwm_apply_state(pwm, &state);
680}
681EXPORT_SYMBOL_GPL(pwm_adjust_config);
682
683static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
684{
685 struct pwm_chip *chip;
686
687 mutex_lock(&pwm_lock);
688
689 list_for_each_entry(chip, &pwm_chips, list)
690 if (chip->dev && device_match_fwnode(chip->dev, fwnode)) {
691 mutex_unlock(&pwm_lock);
692 return chip;
693 }
694
695 mutex_unlock(&pwm_lock);
696
697 return ERR_PTR(-EPROBE_DEFER);
698}
699
700static struct device_link *pwm_device_link_add(struct device *dev,
701 struct pwm_device *pwm)
702{
703 struct device_link *dl;
704
705 if (!dev) {
706 /*
707 * No device for the PWM consumer has been provided. It may
708 * impact the PM sequence ordering: the PWM supplier may get
709 * suspended before the consumer.
710 */
711 dev_warn(pwm->chip->dev,
712 "No consumer device specified to create a link to\n");
713 return NULL;
714 }
715
716 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
717 if (!dl) {
718 dev_err(dev, "failed to create device link to %s\n",
719 dev_name(pwm->chip->dev));
720 return ERR_PTR(-EINVAL);
721 }
722
723 return dl;
724}
725
726/**
727 * of_pwm_get() - request a PWM via the PWM framework
728 * @dev: device for PWM consumer
729 * @np: device node to get the PWM from
730 * @con_id: consumer name
731 *
732 * Returns the PWM device parsed from the phandle and index specified in the
733 * "pwms" property of a device tree node or a negative error-code on failure.
734 * Values parsed from the device tree are stored in the returned PWM device
735 * object.
736 *
737 * If con_id is NULL, the first PWM device listed in the "pwms" property will
738 * be requested. Otherwise the "pwm-names" property is used to do a reverse
739 * lookup of the PWM index. This also means that the "pwm-names" property
740 * becomes mandatory for devices that look up the PWM device via the con_id
741 * parameter.
742 *
743 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
744 * error code on failure.
745 */
746static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
747 const char *con_id)
748{
749 struct pwm_device *pwm = NULL;
750 struct of_phandle_args args;
751 struct device_link *dl;
752 struct pwm_chip *pc;
753 int index = 0;
754 int err;
755
756 if (con_id) {
757 index = of_property_match_string(np, "pwm-names", con_id);
758 if (index < 0)
759 return ERR_PTR(index);
760 }
761
762 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
763 &args);
764 if (err) {
765 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
766 return ERR_PTR(err);
767 }
768
769 pc = fwnode_to_pwmchip(of_fwnode_handle(args.np));
770 if (IS_ERR(pc)) {
771 if (PTR_ERR(pc) != -EPROBE_DEFER)
772 pr_err("%s(): PWM chip not found\n", __func__);
773
774 pwm = ERR_CAST(pc);
775 goto put;
776 }
777
778 pwm = pc->of_xlate(pc, &args);
779 if (IS_ERR(pwm))
780 goto put;
781
782 dl = pwm_device_link_add(dev, pwm);
783 if (IS_ERR(dl)) {
784 /* of_xlate ended up calling pwm_request_from_chip() */
785 pwm_free(pwm);
786 pwm = ERR_CAST(dl);
787 goto put;
788 }
789
790 /*
791 * If a consumer name was not given, try to look it up from the
792 * "pwm-names" property if it exists. Otherwise use the name of
793 * the user device node.
794 */
795 if (!con_id) {
796 err = of_property_read_string_index(np, "pwm-names", index,
797 &con_id);
798 if (err < 0)
799 con_id = np->name;
800 }
801
802 pwm->label = con_id;
803
804put:
805 of_node_put(args.np);
806
807 return pwm;
808}
809
810/**
811 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
812 * @fwnode: firmware node to get the "pwms" property from
813 *
814 * Returns the PWM device parsed from the fwnode and index specified in the
815 * "pwms" property or a negative error-code on failure.
816 * Values parsed from the device tree are stored in the returned PWM device
817 * object.
818 *
819 * This is analogous to of_pwm_get() except con_id is not yet supported.
820 * ACPI entries must look like
821 * Package () {"pwms", Package ()
822 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
823 *
824 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
825 * error code on failure.
826 */
827static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
828{
829 struct pwm_device *pwm;
830 struct fwnode_reference_args args;
831 struct pwm_chip *chip;
832 int ret;
833
834 memset(&args, 0, sizeof(args));
835
836 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
837 if (ret < 0)
838 return ERR_PTR(ret);
839
840 if (args.nargs < 2)
841 return ERR_PTR(-EPROTO);
842
843 chip = fwnode_to_pwmchip(args.fwnode);
844 if (IS_ERR(chip))
845 return ERR_CAST(chip);
846
847 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
848 if (IS_ERR(pwm))
849 return pwm;
850
851 pwm->args.period = args.args[1];
852 pwm->args.polarity = PWM_POLARITY_NORMAL;
853
854 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
855 pwm->args.polarity = PWM_POLARITY_INVERSED;
856
857 return pwm;
858}
859
860/**
861 * pwm_add_table() - register PWM device consumers
862 * @table: array of consumers to register
863 * @num: number of consumers in table
864 */
865void pwm_add_table(struct pwm_lookup *table, size_t num)
866{
867 mutex_lock(&pwm_lookup_lock);
868
869 while (num--) {
870 list_add_tail(&table->list, &pwm_lookup_list);
871 table++;
872 }
873
874 mutex_unlock(&pwm_lookup_lock);
875}
876
877/**
878 * pwm_remove_table() - unregister PWM device consumers
879 * @table: array of consumers to unregister
880 * @num: number of consumers in table
881 */
882void pwm_remove_table(struct pwm_lookup *table, size_t num)
883{
884 mutex_lock(&pwm_lookup_lock);
885
886 while (num--) {
887 list_del(&table->list);
888 table++;
889 }
890
891 mutex_unlock(&pwm_lookup_lock);
892}
893
894/**
895 * pwm_get() - look up and request a PWM device
896 * @dev: device for PWM consumer
897 * @con_id: consumer name
898 *
899 * Lookup is first attempted using DT. If the device was not instantiated from
900 * a device tree, a PWM chip and a relative index is looked up via a table
901 * supplied by board setup code (see pwm_add_table()).
902 *
903 * Once a PWM chip has been found the specified PWM device will be requested
904 * and is ready to be used.
905 *
906 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
907 * error code on failure.
908 */
909struct pwm_device *pwm_get(struct device *dev, const char *con_id)
910{
911 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
912 const char *dev_id = dev ? dev_name(dev) : NULL;
913 struct pwm_device *pwm;
914 struct pwm_chip *chip;
915 struct device_link *dl;
916 unsigned int best = 0;
917 struct pwm_lookup *p, *chosen = NULL;
918 unsigned int match;
919 int err;
920
921 /* look up via DT first */
922 if (is_of_node(fwnode))
923 return of_pwm_get(dev, to_of_node(fwnode), con_id);
924
925 /* then lookup via ACPI */
926 if (is_acpi_node(fwnode)) {
927 pwm = acpi_pwm_get(fwnode);
928 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
929 return pwm;
930 }
931
932 /*
933 * We look up the provider in the static table typically provided by
934 * board setup code. We first try to lookup the consumer device by
935 * name. If the consumer device was passed in as NULL or if no match
936 * was found, we try to find the consumer by directly looking it up
937 * by name.
938 *
939 * If a match is found, the provider PWM chip is looked up by name
940 * and a PWM device is requested using the PWM device per-chip index.
941 *
942 * The lookup algorithm was shamelessly taken from the clock
943 * framework:
944 *
945 * We do slightly fuzzy matching here:
946 * An entry with a NULL ID is assumed to be a wildcard.
947 * If an entry has a device ID, it must match
948 * If an entry has a connection ID, it must match
949 * Then we take the most specific entry - with the following order
950 * of precedence: dev+con > dev only > con only.
951 */
952 mutex_lock(&pwm_lookup_lock);
953
954 list_for_each_entry(p, &pwm_lookup_list, list) {
955 match = 0;
956
957 if (p->dev_id) {
958 if (!dev_id || strcmp(p->dev_id, dev_id))
959 continue;
960
961 match += 2;
962 }
963
964 if (p->con_id) {
965 if (!con_id || strcmp(p->con_id, con_id))
966 continue;
967
968 match += 1;
969 }
970
971 if (match > best) {
972 chosen = p;
973
974 if (match != 3)
975 best = match;
976 else
977 break;
978 }
979 }
980
981 mutex_unlock(&pwm_lookup_lock);
982
983 if (!chosen)
984 return ERR_PTR(-ENODEV);
985
986 chip = pwmchip_find_by_name(chosen->provider);
987
988 /*
989 * If the lookup entry specifies a module, load the module and retry
990 * the PWM chip lookup. This can be used to work around driver load
991 * ordering issues if driver's can't be made to properly support the
992 * deferred probe mechanism.
993 */
994 if (!chip && chosen->module) {
995 err = request_module(chosen->module);
996 if (err == 0)
997 chip = pwmchip_find_by_name(chosen->provider);
998 }
999
1000 if (!chip)
1001 return ERR_PTR(-EPROBE_DEFER);
1002
1003 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1004 if (IS_ERR(pwm))
1005 return pwm;
1006
1007 dl = pwm_device_link_add(dev, pwm);
1008 if (IS_ERR(dl)) {
1009 pwm_free(pwm);
1010 return ERR_CAST(dl);
1011 }
1012
1013 pwm->args.period = chosen->period;
1014 pwm->args.polarity = chosen->polarity;
1015
1016 return pwm;
1017}
1018EXPORT_SYMBOL_GPL(pwm_get);
1019
1020/**
1021 * pwm_put() - release a PWM device
1022 * @pwm: PWM device
1023 */
1024void pwm_put(struct pwm_device *pwm)
1025{
1026 if (!pwm)
1027 return;
1028
1029 mutex_lock(&pwm_lock);
1030
1031 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1032 pr_warn("PWM device already freed\n");
1033 goto out;
1034 }
1035
1036 if (pwm->chip->ops->free)
1037 pwm->chip->ops->free(pwm->chip, pwm);
1038
1039 pwm_set_chip_data(pwm, NULL);
1040 pwm->label = NULL;
1041
1042 module_put(pwm->chip->ops->owner);
1043out:
1044 mutex_unlock(&pwm_lock);
1045}
1046EXPORT_SYMBOL_GPL(pwm_put);
1047
1048static void devm_pwm_release(void *pwm)
1049{
1050 pwm_put(pwm);
1051}
1052
1053/**
1054 * devm_pwm_get() - resource managed pwm_get()
1055 * @dev: device for PWM consumer
1056 * @con_id: consumer name
1057 *
1058 * This function performs like pwm_get() but the acquired PWM device will
1059 * automatically be released on driver detach.
1060 *
1061 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1062 * error code on failure.
1063 */
1064struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1065{
1066 struct pwm_device *pwm;
1067 int ret;
1068
1069 pwm = pwm_get(dev, con_id);
1070 if (IS_ERR(pwm))
1071 return pwm;
1072
1073 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1074 if (ret)
1075 return ERR_PTR(ret);
1076
1077 return pwm;
1078}
1079EXPORT_SYMBOL_GPL(devm_pwm_get);
1080
1081/**
1082 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1083 * @dev: device for PWM consumer
1084 * @fwnode: firmware node to get the PWM from
1085 * @con_id: consumer name
1086 *
1087 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1088 * acpi_pwm_get() for a detailed description.
1089 *
1090 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1091 * error code on failure.
1092 */
1093struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1094 struct fwnode_handle *fwnode,
1095 const char *con_id)
1096{
1097 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1098 int ret;
1099
1100 if (is_of_node(fwnode))
1101 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1102 else if (is_acpi_node(fwnode))
1103 pwm = acpi_pwm_get(fwnode);
1104 if (IS_ERR(pwm))
1105 return pwm;
1106
1107 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1108 if (ret)
1109 return ERR_PTR(ret);
1110
1111 return pwm;
1112}
1113EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1114
1115#ifdef CONFIG_DEBUG_FS
1116static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1117{
1118 unsigned int i;
1119
1120 for (i = 0; i < chip->npwm; i++) {
1121 struct pwm_device *pwm = &chip->pwms[i];
1122 struct pwm_state state;
1123
1124 pwm_get_state(pwm, &state);
1125
1126 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1127
1128 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1129 seq_puts(s, " requested");
1130
1131 if (state.enabled)
1132 seq_puts(s, " enabled");
1133
1134 seq_printf(s, " period: %llu ns", state.period);
1135 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1136 seq_printf(s, " polarity: %s",
1137 state.polarity ? "inverse" : "normal");
1138
1139 if (state.usage_power)
1140 seq_puts(s, " usage_power");
1141
1142 seq_puts(s, "\n");
1143 }
1144}
1145
1146static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1147{
1148 mutex_lock(&pwm_lock);
1149 s->private = "";
1150
1151 return seq_list_start(&pwm_chips, *pos);
1152}
1153
1154static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1155{
1156 s->private = "\n";
1157
1158 return seq_list_next(v, &pwm_chips, pos);
1159}
1160
1161static void pwm_seq_stop(struct seq_file *s, void *v)
1162{
1163 mutex_unlock(&pwm_lock);
1164}
1165
1166static int pwm_seq_show(struct seq_file *s, void *v)
1167{
1168 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1169
1170 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1171 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1172 dev_name(chip->dev), chip->npwm,
1173 (chip->npwm != 1) ? "s" : "");
1174
1175 pwm_dbg_show(chip, s);
1176
1177 return 0;
1178}
1179
1180static const struct seq_operations pwm_debugfs_sops = {
1181 .start = pwm_seq_start,
1182 .next = pwm_seq_next,
1183 .stop = pwm_seq_stop,
1184 .show = pwm_seq_show,
1185};
1186
1187DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1188
1189static int __init pwm_debugfs_init(void)
1190{
1191 debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1192
1193 return 0;
1194}
1195subsys_initcall(pwm_debugfs_init);
1196#endif /* CONFIG_DEBUG_FS */