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
28 static DEFINE_MUTEX(pwm_lookup_lock);
29 static LIST_HEAD(pwm_lookup_list);
30 static DEFINE_MUTEX(pwm_lock);
31 static LIST_HEAD(pwm_chips);
32 static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
33 static RADIX_TREE(pwm_tree, GFP_KERNEL);
34
pwm_to_device(unsigned int pwm)35 static struct pwm_device *pwm_to_device(unsigned int pwm)
36 {
37 return radix_tree_lookup(&pwm_tree, pwm);
38 }
39
alloc_pwms(unsigned int count)40 static int alloc_pwms(unsigned int count)
41 {
42 unsigned int start;
43
44 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, 0,
45 count, 0);
46
47 if (start + count > MAX_PWMS)
48 return -ENOSPC;
49
50 return start;
51 }
52
free_pwms(struct pwm_chip * chip)53 static void free_pwms(struct pwm_chip *chip)
54 {
55 unsigned int i;
56
57 for (i = 0; i < chip->npwm; i++) {
58 struct pwm_device *pwm = &chip->pwms[i];
59
60 radix_tree_delete(&pwm_tree, pwm->pwm);
61 }
62
63 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
64
65 kfree(chip->pwms);
66 chip->pwms = NULL;
67 }
68
pwmchip_find_by_name(const char * name)69 static struct pwm_chip *pwmchip_find_by_name(const char *name)
70 {
71 struct pwm_chip *chip;
72
73 if (!name)
74 return NULL;
75
76 mutex_lock(&pwm_lock);
77
78 list_for_each_entry(chip, &pwm_chips, list) {
79 const char *chip_name = dev_name(chip->dev);
80
81 if (chip_name && strcmp(chip_name, name) == 0) {
82 mutex_unlock(&pwm_lock);
83 return chip;
84 }
85 }
86
87 mutex_unlock(&pwm_lock);
88
89 return NULL;
90 }
91
pwm_device_request(struct pwm_device * pwm,const char * label)92 static int pwm_device_request(struct pwm_device *pwm, const char *label)
93 {
94 int err;
95
96 if (test_bit(PWMF_REQUESTED, &pwm->flags))
97 return -EBUSY;
98
99 if (!try_module_get(pwm->chip->ops->owner))
100 return -ENODEV;
101
102 if (pwm->chip->ops->request) {
103 err = pwm->chip->ops->request(pwm->chip, pwm);
104 if (err) {
105 module_put(pwm->chip->ops->owner);
106 return err;
107 }
108 }
109
110 if (pwm->chip->ops->get_state) {
111 pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
112 trace_pwm_get(pwm, &pwm->state);
113
114 if (IS_ENABLED(CONFIG_PWM_DEBUG))
115 pwm->last = pwm->state;
116 }
117
118 set_bit(PWMF_REQUESTED, &pwm->flags);
119 pwm->label = label;
120
121 return 0;
122 }
123
124 struct pwm_device *
of_pwm_xlate_with_flags(struct pwm_chip * pc,const struct of_phandle_args * args)125 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
126 {
127 struct pwm_device *pwm;
128
129 /* check, whether the driver supports a third cell for flags */
130 if (pc->of_pwm_n_cells < 3)
131 return ERR_PTR(-EINVAL);
132
133 /* flags in the third cell are optional */
134 if (args->args_count < 2)
135 return ERR_PTR(-EINVAL);
136
137 if (args->args[0] >= pc->npwm)
138 return ERR_PTR(-EINVAL);
139
140 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
141 if (IS_ERR(pwm))
142 return pwm;
143
144 pwm->args.period = args->args[1];
145 pwm->args.polarity = PWM_POLARITY_NORMAL;
146
147 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
148 pwm->args.polarity = PWM_POLARITY_INVERSED;
149
150 return pwm;
151 }
152 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
153
154 static struct pwm_device *
of_pwm_simple_xlate(struct pwm_chip * pc,const struct of_phandle_args * args)155 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
156 {
157 struct pwm_device *pwm;
158
159 /* sanity check driver support */
160 if (pc->of_pwm_n_cells < 2)
161 return ERR_PTR(-EINVAL);
162
163 /* all cells are required */
164 if (args->args_count != pc->of_pwm_n_cells)
165 return ERR_PTR(-EINVAL);
166
167 if (args->args[0] >= pc->npwm)
168 return ERR_PTR(-EINVAL);
169
170 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
171 if (IS_ERR(pwm))
172 return pwm;
173
174 pwm->args.period = args->args[1];
175
176 return pwm;
177 }
178
of_pwmchip_add(struct pwm_chip * chip)179 static void of_pwmchip_add(struct pwm_chip *chip)
180 {
181 if (!chip->dev || !chip->dev->of_node)
182 return;
183
184 if (!chip->of_xlate) {
185 chip->of_xlate = of_pwm_simple_xlate;
186 chip->of_pwm_n_cells = 2;
187 }
188
189 of_node_get(chip->dev->of_node);
190 }
191
of_pwmchip_remove(struct pwm_chip * chip)192 static void of_pwmchip_remove(struct pwm_chip *chip)
193 {
194 if (chip->dev)
195 of_node_put(chip->dev->of_node);
196 }
197
198 /**
199 * pwm_set_chip_data() - set private chip data for a PWM
200 * @pwm: PWM device
201 * @data: pointer to chip-specific data
202 *
203 * Returns: 0 on success or a negative error code on failure.
204 */
pwm_set_chip_data(struct pwm_device * pwm,void * data)205 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
206 {
207 if (!pwm)
208 return -EINVAL;
209
210 pwm->chip_data = data;
211
212 return 0;
213 }
214 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
215
216 /**
217 * pwm_get_chip_data() - get private chip data for a PWM
218 * @pwm: PWM device
219 *
220 * Returns: A pointer to the chip-private data for the PWM device.
221 */
pwm_get_chip_data(struct pwm_device * pwm)222 void *pwm_get_chip_data(struct pwm_device *pwm)
223 {
224 return pwm ? pwm->chip_data : NULL;
225 }
226 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
227
pwm_ops_check(const struct pwm_chip * chip)228 static bool pwm_ops_check(const struct pwm_chip *chip)
229 {
230
231 const struct pwm_ops *ops = chip->ops;
232
233 /* driver supports legacy, non-atomic operation */
234 if (ops->config && ops->enable && ops->disable) {
235 if (IS_ENABLED(CONFIG_PWM_DEBUG))
236 dev_warn(chip->dev,
237 "Driver needs updating to atomic API\n");
238
239 return true;
240 }
241
242 if (!ops->apply)
243 return false;
244
245 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
246 dev_warn(chip->dev,
247 "Please implement the .get_state() callback\n");
248
249 return true;
250 }
251
252 /**
253 * pwmchip_add() - register a new PWM chip
254 * @chip: the PWM chip to add
255 *
256 * Register a new PWM chip.
257 *
258 * Returns: 0 on success or a negative error code on failure.
259 */
pwmchip_add(struct pwm_chip * chip)260 int pwmchip_add(struct pwm_chip *chip)
261 {
262 struct pwm_device *pwm;
263 unsigned int i;
264 int ret;
265
266 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
267 return -EINVAL;
268
269 if (!pwm_ops_check(chip))
270 return -EINVAL;
271
272 mutex_lock(&pwm_lock);
273
274 ret = alloc_pwms(chip->npwm);
275 if (ret < 0)
276 goto out;
277
278 chip->base = ret;
279
280 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
281 if (!chip->pwms) {
282 ret = -ENOMEM;
283 goto out;
284 }
285
286 for (i = 0; i < chip->npwm; i++) {
287 pwm = &chip->pwms[i];
288
289 pwm->chip = chip;
290 pwm->pwm = chip->base + i;
291 pwm->hwpwm = i;
292
293 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
294 }
295
296 bitmap_set(allocated_pwms, chip->base, chip->npwm);
297
298 INIT_LIST_HEAD(&chip->list);
299 list_add(&chip->list, &pwm_chips);
300
301 ret = 0;
302
303 if (IS_ENABLED(CONFIG_OF))
304 of_pwmchip_add(chip);
305
306 out:
307 mutex_unlock(&pwm_lock);
308
309 if (!ret)
310 pwmchip_sysfs_export(chip);
311
312 return ret;
313 }
314 EXPORT_SYMBOL_GPL(pwmchip_add);
315
316 /**
317 * pwmchip_remove() - remove a PWM chip
318 * @chip: the PWM chip to remove
319 *
320 * Removes a PWM chip. This function may return busy if the PWM chip provides
321 * a PWM device that is still requested.
322 *
323 * Returns: 0 on success or a negative error code on failure.
324 */
pwmchip_remove(struct pwm_chip * chip)325 int pwmchip_remove(struct pwm_chip *chip)
326 {
327 unsigned int i;
328 int ret = 0;
329
330 pwmchip_sysfs_unexport(chip);
331
332 mutex_lock(&pwm_lock);
333
334 for (i = 0; i < chip->npwm; i++) {
335 struct pwm_device *pwm = &chip->pwms[i];
336
337 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
338 ret = -EBUSY;
339 goto out;
340 }
341 }
342
343 list_del_init(&chip->list);
344
345 if (IS_ENABLED(CONFIG_OF))
346 of_pwmchip_remove(chip);
347
348 free_pwms(chip);
349
350 out:
351 mutex_unlock(&pwm_lock);
352 return ret;
353 }
354 EXPORT_SYMBOL_GPL(pwmchip_remove);
355
356 /**
357 * pwm_request() - request a PWM device
358 * @pwm: global PWM device index
359 * @label: PWM device label
360 *
361 * This function is deprecated, use pwm_get() instead.
362 *
363 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
364 * failure.
365 */
pwm_request(int pwm,const char * label)366 struct pwm_device *pwm_request(int pwm, const char *label)
367 {
368 struct pwm_device *dev;
369 int err;
370
371 if (pwm < 0 || pwm >= MAX_PWMS)
372 return ERR_PTR(-EINVAL);
373
374 mutex_lock(&pwm_lock);
375
376 dev = pwm_to_device(pwm);
377 if (!dev) {
378 dev = ERR_PTR(-EPROBE_DEFER);
379 goto out;
380 }
381
382 err = pwm_device_request(dev, label);
383 if (err < 0)
384 dev = ERR_PTR(err);
385
386 out:
387 mutex_unlock(&pwm_lock);
388
389 return dev;
390 }
391 EXPORT_SYMBOL_GPL(pwm_request);
392
393 /**
394 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
395 * @chip: PWM chip
396 * @index: per-chip index of the PWM to request
397 * @label: a literal description string of this PWM
398 *
399 * Returns: A pointer to the PWM device at the given index of the given PWM
400 * chip. A negative error code is returned if the index is not valid for the
401 * specified PWM chip or if the PWM device cannot be requested.
402 */
pwm_request_from_chip(struct pwm_chip * chip,unsigned int index,const char * label)403 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
404 unsigned int index,
405 const char *label)
406 {
407 struct pwm_device *pwm;
408 int err;
409
410 if (!chip || index >= chip->npwm)
411 return ERR_PTR(-EINVAL);
412
413 mutex_lock(&pwm_lock);
414 pwm = &chip->pwms[index];
415
416 err = pwm_device_request(pwm, label);
417 if (err < 0)
418 pwm = ERR_PTR(err);
419
420 mutex_unlock(&pwm_lock);
421 return pwm;
422 }
423 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
424
425 /**
426 * pwm_free() - free a PWM device
427 * @pwm: PWM device
428 *
429 * This function is deprecated, use pwm_put() instead.
430 */
pwm_free(struct pwm_device * pwm)431 void pwm_free(struct pwm_device *pwm)
432 {
433 pwm_put(pwm);
434 }
435 EXPORT_SYMBOL_GPL(pwm_free);
436
pwm_apply_state_debug(struct pwm_device * pwm,const struct pwm_state * state)437 static void pwm_apply_state_debug(struct pwm_device *pwm,
438 const struct pwm_state *state)
439 {
440 struct pwm_state *last = &pwm->last;
441 struct pwm_chip *chip = pwm->chip;
442 struct pwm_state s1, s2;
443 int err;
444
445 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
446 return;
447
448 /* No reasonable diagnosis possible without .get_state() */
449 if (!chip->ops->get_state)
450 return;
451
452 /*
453 * *state was just applied. Read out the hardware state and do some
454 * checks.
455 */
456
457 chip->ops->get_state(chip, pwm, &s1);
458 trace_pwm_get(pwm, &s1);
459
460 /*
461 * The lowlevel driver either ignored .polarity (which is a bug) or as
462 * best effort inverted .polarity and fixed .duty_cycle respectively.
463 * Undo this inversion and fixup for further tests.
464 */
465 if (s1.enabled && s1.polarity != state->polarity) {
466 s2.polarity = state->polarity;
467 s2.duty_cycle = s1.period - s1.duty_cycle;
468 s2.period = s1.period;
469 s2.enabled = s1.enabled;
470 } else {
471 s2 = s1;
472 }
473
474 if (s2.polarity != state->polarity &&
475 state->duty_cycle < state->period)
476 dev_warn(chip->dev, ".apply ignored .polarity\n");
477
478 if (state->enabled &&
479 last->polarity == state->polarity &&
480 last->period > s2.period &&
481 last->period <= state->period)
482 dev_warn(chip->dev,
483 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
484 state->period, s2.period, last->period);
485
486 if (state->enabled && state->period < s2.period)
487 dev_warn(chip->dev,
488 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
489 state->period, s2.period);
490
491 if (state->enabled &&
492 last->polarity == state->polarity &&
493 last->period == s2.period &&
494 last->duty_cycle > s2.duty_cycle &&
495 last->duty_cycle <= state->duty_cycle)
496 dev_warn(chip->dev,
497 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
498 state->duty_cycle, state->period,
499 s2.duty_cycle, s2.period,
500 last->duty_cycle, last->period);
501
502 if (state->enabled && state->duty_cycle < s2.duty_cycle)
503 dev_warn(chip->dev,
504 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
505 state->duty_cycle, state->period,
506 s2.duty_cycle, s2.period);
507
508 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
509 dev_warn(chip->dev,
510 "requested disabled, but yielded enabled with duty > 0\n");
511
512 /* reapply the state that the driver reported being configured. */
513 err = chip->ops->apply(chip, pwm, &s1);
514 if (err) {
515 *last = s1;
516 dev_err(chip->dev, "failed to reapply current setting\n");
517 return;
518 }
519
520 trace_pwm_apply(pwm, &s1);
521
522 chip->ops->get_state(chip, pwm, last);
523 trace_pwm_get(pwm, last);
524
525 /* reapplication of the current state should give an exact match */
526 if (s1.enabled != last->enabled ||
527 s1.polarity != last->polarity ||
528 (s1.enabled && s1.period != last->period) ||
529 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
530 dev_err(chip->dev,
531 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
532 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
533 last->enabled, last->polarity, last->duty_cycle,
534 last->period);
535 }
536 }
537
538 /**
539 * pwm_apply_state() - atomically apply a new state to a PWM device
540 * @pwm: PWM device
541 * @state: new state to apply
542 */
pwm_apply_state(struct pwm_device * pwm,const struct pwm_state * state)543 int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
544 {
545 struct pwm_chip *chip;
546 int err;
547
548 if (!pwm || !state || !state->period ||
549 state->duty_cycle > state->period)
550 return -EINVAL;
551
552 chip = pwm->chip;
553
554 if (state->period == pwm->state.period &&
555 state->duty_cycle == pwm->state.duty_cycle &&
556 state->polarity == pwm->state.polarity &&
557 state->enabled == pwm->state.enabled)
558 return 0;
559
560 if (chip->ops->apply) {
561 err = chip->ops->apply(chip, pwm, state);
562 if (err)
563 return err;
564
565 trace_pwm_apply(pwm, state);
566
567 pwm->state = *state;
568
569 /*
570 * only do this after pwm->state was applied as some
571 * implementations of .get_state depend on this
572 */
573 pwm_apply_state_debug(pwm, state);
574 } else {
575 /*
576 * FIXME: restore the initial state in case of error.
577 */
578 if (state->polarity != pwm->state.polarity) {
579 if (!chip->ops->set_polarity)
580 return -EINVAL;
581
582 /*
583 * Changing the polarity of a running PWM is
584 * only allowed when the PWM driver implements
585 * ->apply().
586 */
587 if (pwm->state.enabled) {
588 chip->ops->disable(chip, pwm);
589 pwm->state.enabled = false;
590 }
591
592 err = chip->ops->set_polarity(chip, pwm,
593 state->polarity);
594 if (err)
595 return err;
596
597 pwm->state.polarity = state->polarity;
598 }
599
600 if (state->period != pwm->state.period ||
601 state->duty_cycle != pwm->state.duty_cycle) {
602 err = chip->ops->config(pwm->chip, pwm,
603 state->duty_cycle,
604 state->period);
605 if (err)
606 return err;
607
608 pwm->state.duty_cycle = state->duty_cycle;
609 pwm->state.period = state->period;
610 }
611
612 if (state->enabled != pwm->state.enabled) {
613 if (state->enabled) {
614 err = chip->ops->enable(chip, pwm);
615 if (err)
616 return err;
617 } else {
618 chip->ops->disable(chip, pwm);
619 }
620
621 pwm->state.enabled = state->enabled;
622 }
623 }
624
625 return 0;
626 }
627 EXPORT_SYMBOL_GPL(pwm_apply_state);
628
629 /**
630 * pwm_capture() - capture and report a PWM signal
631 * @pwm: PWM device
632 * @result: structure to fill with capture result
633 * @timeout: time to wait, in milliseconds, before giving up on capture
634 *
635 * Returns: 0 on success or a negative error code on failure.
636 */
pwm_capture(struct pwm_device * pwm,struct pwm_capture * result,unsigned long timeout)637 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
638 unsigned long timeout)
639 {
640 int err;
641
642 if (!pwm || !pwm->chip->ops)
643 return -EINVAL;
644
645 if (!pwm->chip->ops->capture)
646 return -ENOSYS;
647
648 mutex_lock(&pwm_lock);
649 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
650 mutex_unlock(&pwm_lock);
651
652 return err;
653 }
654 EXPORT_SYMBOL_GPL(pwm_capture);
655
656 /**
657 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
658 * @pwm: PWM device
659 *
660 * This function will adjust the PWM config to the PWM arguments provided
661 * by the DT or PWM lookup table. This is particularly useful to adapt
662 * the bootloader config to the Linux one.
663 */
pwm_adjust_config(struct pwm_device * pwm)664 int pwm_adjust_config(struct pwm_device *pwm)
665 {
666 struct pwm_state state;
667 struct pwm_args pargs;
668
669 pwm_get_args(pwm, &pargs);
670 pwm_get_state(pwm, &state);
671
672 /*
673 * If the current period is zero it means that either the PWM driver
674 * does not support initial state retrieval or the PWM has not yet
675 * been configured.
676 *
677 * In either case, we setup the new period and polarity, and assign a
678 * duty cycle of 0.
679 */
680 if (!state.period) {
681 state.duty_cycle = 0;
682 state.period = pargs.period;
683 state.polarity = pargs.polarity;
684
685 return pwm_apply_state(pwm, &state);
686 }
687
688 /*
689 * Adjust the PWM duty cycle/period based on the period value provided
690 * in PWM args.
691 */
692 if (pargs.period != state.period) {
693 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
694
695 do_div(dutycycle, state.period);
696 state.duty_cycle = dutycycle;
697 state.period = pargs.period;
698 }
699
700 /*
701 * If the polarity changed, we should also change the duty cycle.
702 */
703 if (pargs.polarity != state.polarity) {
704 state.polarity = pargs.polarity;
705 state.duty_cycle = state.period - state.duty_cycle;
706 }
707
708 return pwm_apply_state(pwm, &state);
709 }
710 EXPORT_SYMBOL_GPL(pwm_adjust_config);
711
of_node_to_pwmchip(struct device_node * np)712 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
713 {
714 struct pwm_chip *chip;
715
716 mutex_lock(&pwm_lock);
717
718 list_for_each_entry(chip, &pwm_chips, list)
719 if (chip->dev && chip->dev->of_node == np) {
720 mutex_unlock(&pwm_lock);
721 return chip;
722 }
723
724 mutex_unlock(&pwm_lock);
725
726 return ERR_PTR(-EPROBE_DEFER);
727 }
728
pwm_device_link_add(struct device * dev,struct pwm_device * pwm)729 static struct device_link *pwm_device_link_add(struct device *dev,
730 struct pwm_device *pwm)
731 {
732 struct device_link *dl;
733
734 if (!dev) {
735 /*
736 * No device for the PWM consumer has been provided. It may
737 * impact the PM sequence ordering: the PWM supplier may get
738 * suspended before the consumer.
739 */
740 dev_warn(pwm->chip->dev,
741 "No consumer device specified to create a link to\n");
742 return NULL;
743 }
744
745 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
746 if (!dl) {
747 dev_err(dev, "failed to create device link to %s\n",
748 dev_name(pwm->chip->dev));
749 return ERR_PTR(-EINVAL);
750 }
751
752 return dl;
753 }
754
755 /**
756 * of_pwm_get() - request a PWM via the PWM framework
757 * @dev: device for PWM consumer
758 * @np: device node to get the PWM from
759 * @con_id: consumer name
760 *
761 * Returns the PWM device parsed from the phandle and index specified in the
762 * "pwms" property of a device tree node or a negative error-code on failure.
763 * Values parsed from the device tree are stored in the returned PWM device
764 * object.
765 *
766 * If con_id is NULL, the first PWM device listed in the "pwms" property will
767 * be requested. Otherwise the "pwm-names" property is used to do a reverse
768 * lookup of the PWM index. This also means that the "pwm-names" property
769 * becomes mandatory for devices that look up the PWM device via the con_id
770 * parameter.
771 *
772 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
773 * error code on failure.
774 */
of_pwm_get(struct device * dev,struct device_node * np,const char * con_id)775 struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
776 const char *con_id)
777 {
778 struct pwm_device *pwm = NULL;
779 struct of_phandle_args args;
780 struct device_link *dl;
781 struct pwm_chip *pc;
782 int index = 0;
783 int err;
784
785 if (con_id) {
786 index = of_property_match_string(np, "pwm-names", con_id);
787 if (index < 0)
788 return ERR_PTR(index);
789 }
790
791 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
792 &args);
793 if (err) {
794 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
795 return ERR_PTR(err);
796 }
797
798 pc = of_node_to_pwmchip(args.np);
799 if (IS_ERR(pc)) {
800 if (PTR_ERR(pc) != -EPROBE_DEFER)
801 pr_err("%s(): PWM chip not found\n", __func__);
802
803 pwm = ERR_CAST(pc);
804 goto put;
805 }
806
807 pwm = pc->of_xlate(pc, &args);
808 if (IS_ERR(pwm))
809 goto put;
810
811 dl = pwm_device_link_add(dev, pwm);
812 if (IS_ERR(dl)) {
813 /* of_xlate ended up calling pwm_request_from_chip() */
814 pwm_free(pwm);
815 pwm = ERR_CAST(dl);
816 goto put;
817 }
818
819 /*
820 * If a consumer name was not given, try to look it up from the
821 * "pwm-names" property if it exists. Otherwise use the name of
822 * the user device node.
823 */
824 if (!con_id) {
825 err = of_property_read_string_index(np, "pwm-names", index,
826 &con_id);
827 if (err < 0)
828 con_id = np->name;
829 }
830
831 pwm->label = con_id;
832
833 put:
834 of_node_put(args.np);
835
836 return pwm;
837 }
838 EXPORT_SYMBOL_GPL(of_pwm_get);
839
840 #if IS_ENABLED(CONFIG_ACPI)
device_to_pwmchip(struct device * dev)841 static struct pwm_chip *device_to_pwmchip(struct device *dev)
842 {
843 struct pwm_chip *chip;
844
845 mutex_lock(&pwm_lock);
846
847 list_for_each_entry(chip, &pwm_chips, list) {
848 struct acpi_device *adev = ACPI_COMPANION(chip->dev);
849
850 if ((chip->dev == dev) || (adev && &adev->dev == dev)) {
851 mutex_unlock(&pwm_lock);
852 return chip;
853 }
854 }
855
856 mutex_unlock(&pwm_lock);
857
858 return ERR_PTR(-EPROBE_DEFER);
859 }
860 #endif
861
862 /**
863 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
864 * @fwnode: firmware node to get the "pwm" property from
865 *
866 * Returns the PWM device parsed from the fwnode and index specified in the
867 * "pwms" property or a negative error-code on failure.
868 * Values parsed from the device tree are stored in the returned PWM device
869 * object.
870 *
871 * This is analogous to of_pwm_get() except con_id is not yet supported.
872 * ACPI entries must look like
873 * Package () {"pwms", Package ()
874 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
875 *
876 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
877 * error code on failure.
878 */
acpi_pwm_get(struct fwnode_handle * fwnode)879 static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
880 {
881 struct pwm_device *pwm = ERR_PTR(-ENODEV);
882 #if IS_ENABLED(CONFIG_ACPI)
883 struct fwnode_reference_args args;
884 struct acpi_device *acpi;
885 struct pwm_chip *chip;
886 int ret;
887
888 memset(&args, 0, sizeof(args));
889
890 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
891 if (ret < 0)
892 return ERR_PTR(ret);
893
894 acpi = to_acpi_device_node(args.fwnode);
895 if (!acpi)
896 return ERR_PTR(-EINVAL);
897
898 if (args.nargs < 2)
899 return ERR_PTR(-EPROTO);
900
901 chip = device_to_pwmchip(&acpi->dev);
902 if (IS_ERR(chip))
903 return ERR_CAST(chip);
904
905 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
906 if (IS_ERR(pwm))
907 return pwm;
908
909 pwm->args.period = args.args[1];
910 pwm->args.polarity = PWM_POLARITY_NORMAL;
911
912 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
913 pwm->args.polarity = PWM_POLARITY_INVERSED;
914 #endif
915
916 return pwm;
917 }
918
919 /**
920 * pwm_add_table() - register PWM device consumers
921 * @table: array of consumers to register
922 * @num: number of consumers in table
923 */
pwm_add_table(struct pwm_lookup * table,size_t num)924 void pwm_add_table(struct pwm_lookup *table, size_t num)
925 {
926 mutex_lock(&pwm_lookup_lock);
927
928 while (num--) {
929 list_add_tail(&table->list, &pwm_lookup_list);
930 table++;
931 }
932
933 mutex_unlock(&pwm_lookup_lock);
934 }
935
936 /**
937 * pwm_remove_table() - unregister PWM device consumers
938 * @table: array of consumers to unregister
939 * @num: number of consumers in table
940 */
pwm_remove_table(struct pwm_lookup * table,size_t num)941 void pwm_remove_table(struct pwm_lookup *table, size_t num)
942 {
943 mutex_lock(&pwm_lookup_lock);
944
945 while (num--) {
946 list_del(&table->list);
947 table++;
948 }
949
950 mutex_unlock(&pwm_lookup_lock);
951 }
952
953 /**
954 * pwm_get() - look up and request a PWM device
955 * @dev: device for PWM consumer
956 * @con_id: consumer name
957 *
958 * Lookup is first attempted using DT. If the device was not instantiated from
959 * a device tree, a PWM chip and a relative index is looked up via a table
960 * supplied by board setup code (see pwm_add_table()).
961 *
962 * Once a PWM chip has been found the specified PWM device will be requested
963 * and is ready to be used.
964 *
965 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
966 * error code on failure.
967 */
pwm_get(struct device * dev,const char * con_id)968 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
969 {
970 const char *dev_id = dev ? dev_name(dev) : NULL;
971 struct pwm_device *pwm;
972 struct pwm_chip *chip;
973 struct device_link *dl;
974 unsigned int best = 0;
975 struct pwm_lookup *p, *chosen = NULL;
976 unsigned int match;
977 int err;
978
979 /* look up via DT first */
980 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
981 return of_pwm_get(dev, dev->of_node, con_id);
982
983 /* then lookup via ACPI */
984 if (dev && is_acpi_node(dev->fwnode)) {
985 pwm = acpi_pwm_get(dev->fwnode);
986 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
987 return pwm;
988 }
989
990 /*
991 * We look up the provider in the static table typically provided by
992 * board setup code. We first try to lookup the consumer device by
993 * name. If the consumer device was passed in as NULL or if no match
994 * was found, we try to find the consumer by directly looking it up
995 * by name.
996 *
997 * If a match is found, the provider PWM chip is looked up by name
998 * and a PWM device is requested using the PWM device per-chip index.
999 *
1000 * The lookup algorithm was shamelessly taken from the clock
1001 * framework:
1002 *
1003 * We do slightly fuzzy matching here:
1004 * An entry with a NULL ID is assumed to be a wildcard.
1005 * If an entry has a device ID, it must match
1006 * If an entry has a connection ID, it must match
1007 * Then we take the most specific entry - with the following order
1008 * of precedence: dev+con > dev only > con only.
1009 */
1010 mutex_lock(&pwm_lookup_lock);
1011
1012 list_for_each_entry(p, &pwm_lookup_list, list) {
1013 match = 0;
1014
1015 if (p->dev_id) {
1016 if (!dev_id || strcmp(p->dev_id, dev_id))
1017 continue;
1018
1019 match += 2;
1020 }
1021
1022 if (p->con_id) {
1023 if (!con_id || strcmp(p->con_id, con_id))
1024 continue;
1025
1026 match += 1;
1027 }
1028
1029 if (match > best) {
1030 chosen = p;
1031
1032 if (match != 3)
1033 best = match;
1034 else
1035 break;
1036 }
1037 }
1038
1039 mutex_unlock(&pwm_lookup_lock);
1040
1041 if (!chosen)
1042 return ERR_PTR(-ENODEV);
1043
1044 chip = pwmchip_find_by_name(chosen->provider);
1045
1046 /*
1047 * If the lookup entry specifies a module, load the module and retry
1048 * the PWM chip lookup. This can be used to work around driver load
1049 * ordering issues if driver's can't be made to properly support the
1050 * deferred probe mechanism.
1051 */
1052 if (!chip && chosen->module) {
1053 err = request_module(chosen->module);
1054 if (err == 0)
1055 chip = pwmchip_find_by_name(chosen->provider);
1056 }
1057
1058 if (!chip)
1059 return ERR_PTR(-EPROBE_DEFER);
1060
1061 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1062 if (IS_ERR(pwm))
1063 return pwm;
1064
1065 dl = pwm_device_link_add(dev, pwm);
1066 if (IS_ERR(dl)) {
1067 pwm_free(pwm);
1068 return ERR_CAST(dl);
1069 }
1070
1071 pwm->args.period = chosen->period;
1072 pwm->args.polarity = chosen->polarity;
1073
1074 return pwm;
1075 }
1076 EXPORT_SYMBOL_GPL(pwm_get);
1077
1078 /**
1079 * pwm_put() - release a PWM device
1080 * @pwm: PWM device
1081 */
pwm_put(struct pwm_device * pwm)1082 void pwm_put(struct pwm_device *pwm)
1083 {
1084 if (!pwm)
1085 return;
1086
1087 mutex_lock(&pwm_lock);
1088
1089 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1090 pr_warn("PWM device already freed\n");
1091 goto out;
1092 }
1093
1094 if (pwm->chip->ops->free)
1095 pwm->chip->ops->free(pwm->chip, pwm);
1096
1097 pwm_set_chip_data(pwm, NULL);
1098 pwm->label = NULL;
1099
1100 module_put(pwm->chip->ops->owner);
1101 out:
1102 mutex_unlock(&pwm_lock);
1103 }
1104 EXPORT_SYMBOL_GPL(pwm_put);
1105
devm_pwm_release(struct device * dev,void * res)1106 static void devm_pwm_release(struct device *dev, void *res)
1107 {
1108 pwm_put(*(struct pwm_device **)res);
1109 }
1110
1111 /**
1112 * devm_pwm_get() - resource managed pwm_get()
1113 * @dev: device for PWM consumer
1114 * @con_id: consumer name
1115 *
1116 * This function performs like pwm_get() but the acquired PWM device will
1117 * automatically be released on driver detach.
1118 *
1119 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1120 * error code on failure.
1121 */
devm_pwm_get(struct device * dev,const char * con_id)1122 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1123 {
1124 struct pwm_device **ptr, *pwm;
1125
1126 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1127 if (!ptr)
1128 return ERR_PTR(-ENOMEM);
1129
1130 pwm = pwm_get(dev, con_id);
1131 if (!IS_ERR(pwm)) {
1132 *ptr = pwm;
1133 devres_add(dev, ptr);
1134 } else {
1135 devres_free(ptr);
1136 }
1137
1138 return pwm;
1139 }
1140 EXPORT_SYMBOL_GPL(devm_pwm_get);
1141
1142 /**
1143 * devm_of_pwm_get() - resource managed of_pwm_get()
1144 * @dev: device for PWM consumer
1145 * @np: device node to get the PWM from
1146 * @con_id: consumer name
1147 *
1148 * This function performs like of_pwm_get() but the acquired PWM device will
1149 * automatically be released on driver detach.
1150 *
1151 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1152 * error code on failure.
1153 */
devm_of_pwm_get(struct device * dev,struct device_node * np,const char * con_id)1154 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
1155 const char *con_id)
1156 {
1157 struct pwm_device **ptr, *pwm;
1158
1159 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1160 if (!ptr)
1161 return ERR_PTR(-ENOMEM);
1162
1163 pwm = of_pwm_get(dev, np, con_id);
1164 if (!IS_ERR(pwm)) {
1165 *ptr = pwm;
1166 devres_add(dev, ptr);
1167 } else {
1168 devres_free(ptr);
1169 }
1170
1171 return pwm;
1172 }
1173 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
1174
1175 /**
1176 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1177 * @dev: device for PWM consumer
1178 * @fwnode: firmware node to get the PWM from
1179 * @con_id: consumer name
1180 *
1181 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1182 * acpi_pwm_get() for a detailed description.
1183 *
1184 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1185 * error code on failure.
1186 */
devm_fwnode_pwm_get(struct device * dev,struct fwnode_handle * fwnode,const char * con_id)1187 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1188 struct fwnode_handle *fwnode,
1189 const char *con_id)
1190 {
1191 struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV);
1192
1193 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
1194 if (!ptr)
1195 return ERR_PTR(-ENOMEM);
1196
1197 if (is_of_node(fwnode))
1198 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1199 else if (is_acpi_node(fwnode))
1200 pwm = acpi_pwm_get(fwnode);
1201
1202 if (!IS_ERR(pwm)) {
1203 *ptr = pwm;
1204 devres_add(dev, ptr);
1205 } else {
1206 devres_free(ptr);
1207 }
1208
1209 return pwm;
1210 }
1211 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1212
devm_pwm_match(struct device * dev,void * res,void * data)1213 static int devm_pwm_match(struct device *dev, void *res, void *data)
1214 {
1215 struct pwm_device **p = res;
1216
1217 if (WARN_ON(!p || !*p))
1218 return 0;
1219
1220 return *p == data;
1221 }
1222
1223 /**
1224 * devm_pwm_put() - resource managed pwm_put()
1225 * @dev: device for PWM consumer
1226 * @pwm: PWM device
1227 *
1228 * Release a PWM previously allocated using devm_pwm_get(). Calling this
1229 * function is usually not needed because devm-allocated resources are
1230 * automatically released on driver detach.
1231 */
devm_pwm_put(struct device * dev,struct pwm_device * pwm)1232 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
1233 {
1234 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
1235 }
1236 EXPORT_SYMBOL_GPL(devm_pwm_put);
1237
1238 #ifdef CONFIG_DEBUG_FS
pwm_dbg_show(struct pwm_chip * chip,struct seq_file * s)1239 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1240 {
1241 unsigned int i;
1242
1243 for (i = 0; i < chip->npwm; i++) {
1244 struct pwm_device *pwm = &chip->pwms[i];
1245 struct pwm_state state;
1246
1247 pwm_get_state(pwm, &state);
1248
1249 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1250
1251 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1252 seq_puts(s, " requested");
1253
1254 if (state.enabled)
1255 seq_puts(s, " enabled");
1256
1257 seq_printf(s, " period: %llu ns", state.period);
1258 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1259 seq_printf(s, " polarity: %s",
1260 state.polarity ? "inverse" : "normal");
1261
1262 seq_puts(s, "\n");
1263 }
1264 }
1265
pwm_seq_start(struct seq_file * s,loff_t * pos)1266 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1267 {
1268 mutex_lock(&pwm_lock);
1269 s->private = "";
1270
1271 return seq_list_start(&pwm_chips, *pos);
1272 }
1273
pwm_seq_next(struct seq_file * s,void * v,loff_t * pos)1274 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1275 {
1276 s->private = "\n";
1277
1278 return seq_list_next(v, &pwm_chips, pos);
1279 }
1280
pwm_seq_stop(struct seq_file * s,void * v)1281 static void pwm_seq_stop(struct seq_file *s, void *v)
1282 {
1283 mutex_unlock(&pwm_lock);
1284 }
1285
pwm_seq_show(struct seq_file * s,void * v)1286 static int pwm_seq_show(struct seq_file *s, void *v)
1287 {
1288 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1289
1290 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1291 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1292 dev_name(chip->dev), chip->npwm,
1293 (chip->npwm != 1) ? "s" : "");
1294
1295 pwm_dbg_show(chip, s);
1296
1297 return 0;
1298 }
1299
1300 static const struct seq_operations pwm_debugfs_sops = {
1301 .start = pwm_seq_start,
1302 .next = pwm_seq_next,
1303 .stop = pwm_seq_stop,
1304 .show = pwm_seq_show,
1305 };
1306
1307 DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1308
pwm_debugfs_init(void)1309 static int __init pwm_debugfs_init(void)
1310 {
1311 debugfs_create_file("pwm", S_IFREG | 0444, NULL, NULL,
1312 &pwm_debugfs_fops);
1313
1314 return 0;
1315 }
1316 subsys_initcall(pwm_debugfs_init);
1317 #endif /* CONFIG_DEBUG_FS */
1318