Loading...
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/idr.h>
12#include <linux/of.h>
13#include <linux/pwm.h>
14#include <linux/list.h>
15#include <linux/mutex.h>
16#include <linux/err.h>
17#include <linux/slab.h>
18#include <linux/device.h>
19#include <linux/debugfs.h>
20#include <linux/seq_file.h>
21
22#include <dt-bindings/pwm/pwm.h>
23
24#define CREATE_TRACE_POINTS
25#include <trace/events/pwm.h>
26
27static DEFINE_MUTEX(pwm_lookup_lock);
28static LIST_HEAD(pwm_lookup_list);
29
30/* protects access to pwm_chips */
31static DEFINE_MUTEX(pwm_lock);
32
33static DEFINE_IDR(pwm_chips);
34
35static struct pwm_chip *pwmchip_find_by_name(const char *name)
36{
37 struct pwm_chip *chip;
38 unsigned long id, tmp;
39
40 if (!name)
41 return NULL;
42
43 mutex_lock(&pwm_lock);
44
45 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
46 const char *chip_name = dev_name(chip->dev);
47
48 if (chip_name && strcmp(chip_name, name) == 0) {
49 mutex_unlock(&pwm_lock);
50 return chip;
51 }
52 }
53
54 mutex_unlock(&pwm_lock);
55
56 return NULL;
57}
58
59static int pwm_device_request(struct pwm_device *pwm, const char *label)
60{
61 int err;
62 struct pwm_chip *chip = pwm->chip;
63 const struct pwm_ops *ops = chip->ops;
64
65 if (test_bit(PWMF_REQUESTED, &pwm->flags))
66 return -EBUSY;
67
68 if (!try_module_get(chip->owner))
69 return -ENODEV;
70
71 if (ops->request) {
72 err = ops->request(chip, pwm);
73 if (err) {
74 module_put(chip->owner);
75 return err;
76 }
77 }
78
79 if (ops->get_state) {
80 /*
81 * Zero-initialize state because most drivers are unaware of
82 * .usage_power. The other members of state are supposed to be
83 * set by lowlevel drivers. We still initialize the whole
84 * structure for simplicity even though this might paper over
85 * faulty implementations of .get_state().
86 */
87 struct pwm_state state = { 0, };
88
89 err = ops->get_state(chip, pwm, &state);
90 trace_pwm_get(pwm, &state, err);
91
92 if (!err)
93 pwm->state = state;
94
95 if (IS_ENABLED(CONFIG_PWM_DEBUG))
96 pwm->last = pwm->state;
97 }
98
99 set_bit(PWMF_REQUESTED, &pwm->flags);
100 pwm->label = label;
101
102 return 0;
103}
104
105struct pwm_device *
106of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
107{
108 struct pwm_device *pwm;
109
110 if (chip->of_pwm_n_cells < 2)
111 return ERR_PTR(-EINVAL);
112
113 /* flags in the third cell are optional */
114 if (args->args_count < 2)
115 return ERR_PTR(-EINVAL);
116
117 if (args->args[0] >= chip->npwm)
118 return ERR_PTR(-EINVAL);
119
120 pwm = pwm_request_from_chip(chip, args->args[0], NULL);
121 if (IS_ERR(pwm))
122 return pwm;
123
124 pwm->args.period = args->args[1];
125 pwm->args.polarity = PWM_POLARITY_NORMAL;
126
127 if (chip->of_pwm_n_cells >= 3) {
128 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
129 pwm->args.polarity = PWM_POLARITY_INVERSED;
130 }
131
132 return pwm;
133}
134EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
135
136struct pwm_device *
137of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
138{
139 struct pwm_device *pwm;
140
141 if (chip->of_pwm_n_cells < 1)
142 return ERR_PTR(-EINVAL);
143
144 /* validate that one cell is specified, optionally with flags */
145 if (args->args_count != 1 && args->args_count != 2)
146 return ERR_PTR(-EINVAL);
147
148 pwm = pwm_request_from_chip(chip, 0, NULL);
149 if (IS_ERR(pwm))
150 return pwm;
151
152 pwm->args.period = args->args[0];
153 pwm->args.polarity = PWM_POLARITY_NORMAL;
154
155 if (args->args_count == 2 && args->args[1] & PWM_POLARITY_INVERTED)
156 pwm->args.polarity = PWM_POLARITY_INVERSED;
157
158 return pwm;
159}
160EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
161
162static void of_pwmchip_add(struct pwm_chip *chip)
163{
164 if (!chip->dev || !chip->dev->of_node)
165 return;
166
167 if (!chip->of_xlate) {
168 u32 pwm_cells;
169
170 if (of_property_read_u32(chip->dev->of_node, "#pwm-cells",
171 &pwm_cells))
172 pwm_cells = 2;
173
174 chip->of_xlate = of_pwm_xlate_with_flags;
175 chip->of_pwm_n_cells = pwm_cells;
176 }
177
178 of_node_get(chip->dev->of_node);
179}
180
181static void of_pwmchip_remove(struct pwm_chip *chip)
182{
183 if (chip->dev)
184 of_node_put(chip->dev->of_node);
185}
186
187static bool pwm_ops_check(const struct pwm_chip *chip)
188{
189 const struct pwm_ops *ops = chip->ops;
190
191 if (!ops->apply)
192 return false;
193
194 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
195 dev_warn(chip->dev,
196 "Please implement the .get_state() callback\n");
197
198 return true;
199}
200
201/**
202 * __pwmchip_add() - register a new PWM chip
203 * @chip: the PWM chip to add
204 * @owner: reference to the module providing the chip.
205 *
206 * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
207 * pwmchip_add wrapper to do this right.
208 *
209 * Returns: 0 on success or a negative error code on failure.
210 */
211int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
212{
213 unsigned int i;
214 int ret;
215
216 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
217 return -EINVAL;
218
219 if (!pwm_ops_check(chip))
220 return -EINVAL;
221
222 chip->owner = owner;
223
224 chip->pwms = kcalloc(chip->npwm, sizeof(*chip->pwms), GFP_KERNEL);
225 if (!chip->pwms)
226 return -ENOMEM;
227
228 mutex_lock(&pwm_lock);
229
230 ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
231 if (ret < 0) {
232 mutex_unlock(&pwm_lock);
233 kfree(chip->pwms);
234 return ret;
235 }
236
237 chip->id = ret;
238
239 for (i = 0; i < chip->npwm; i++) {
240 struct pwm_device *pwm = &chip->pwms[i];
241
242 pwm->chip = chip;
243 pwm->hwpwm = i;
244 }
245
246 mutex_unlock(&pwm_lock);
247
248 if (IS_ENABLED(CONFIG_OF))
249 of_pwmchip_add(chip);
250
251 pwmchip_sysfs_export(chip);
252
253 return 0;
254}
255EXPORT_SYMBOL_GPL(__pwmchip_add);
256
257/**
258 * pwmchip_remove() - remove a PWM chip
259 * @chip: the PWM chip to remove
260 *
261 * Removes a PWM chip.
262 */
263void pwmchip_remove(struct pwm_chip *chip)
264{
265 pwmchip_sysfs_unexport(chip);
266
267 if (IS_ENABLED(CONFIG_OF))
268 of_pwmchip_remove(chip);
269
270 mutex_lock(&pwm_lock);
271
272 idr_remove(&pwm_chips, chip->id);
273
274 mutex_unlock(&pwm_lock);
275
276 kfree(chip->pwms);
277}
278EXPORT_SYMBOL_GPL(pwmchip_remove);
279
280static void devm_pwmchip_remove(void *data)
281{
282 struct pwm_chip *chip = data;
283
284 pwmchip_remove(chip);
285}
286
287int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
288{
289 int ret;
290
291 ret = __pwmchip_add(chip, owner);
292 if (ret)
293 return ret;
294
295 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
296}
297EXPORT_SYMBOL_GPL(__devm_pwmchip_add);
298
299/**
300 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
301 * @chip: PWM chip
302 * @index: per-chip index of the PWM to request
303 * @label: a literal description string of this PWM
304 *
305 * Returns: A pointer to the PWM device at the given index of the given PWM
306 * chip. A negative error code is returned if the index is not valid for the
307 * specified PWM chip or if the PWM device cannot be requested.
308 */
309struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
310 unsigned int index,
311 const char *label)
312{
313 struct pwm_device *pwm;
314 int err;
315
316 if (!chip || index >= chip->npwm)
317 return ERR_PTR(-EINVAL);
318
319 mutex_lock(&pwm_lock);
320 pwm = &chip->pwms[index];
321
322 err = pwm_device_request(pwm, label);
323 if (err < 0)
324 pwm = ERR_PTR(err);
325
326 mutex_unlock(&pwm_lock);
327 return pwm;
328}
329EXPORT_SYMBOL_GPL(pwm_request_from_chip);
330
331static void pwm_apply_debug(struct pwm_device *pwm,
332 const struct pwm_state *state)
333{
334 struct pwm_state *last = &pwm->last;
335 struct pwm_chip *chip = pwm->chip;
336 struct pwm_state s1 = { 0 }, s2 = { 0 };
337 int err;
338
339 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
340 return;
341
342 /* No reasonable diagnosis possible without .get_state() */
343 if (!chip->ops->get_state)
344 return;
345
346 /*
347 * *state was just applied. Read out the hardware state and do some
348 * checks.
349 */
350
351 err = chip->ops->get_state(chip, pwm, &s1);
352 trace_pwm_get(pwm, &s1, err);
353 if (err)
354 /* If that failed there isn't much to debug */
355 return;
356
357 /*
358 * The lowlevel driver either ignored .polarity (which is a bug) or as
359 * best effort inverted .polarity and fixed .duty_cycle respectively.
360 * Undo this inversion and fixup for further tests.
361 */
362 if (s1.enabled && s1.polarity != state->polarity) {
363 s2.polarity = state->polarity;
364 s2.duty_cycle = s1.period - s1.duty_cycle;
365 s2.period = s1.period;
366 s2.enabled = s1.enabled;
367 } else {
368 s2 = s1;
369 }
370
371 if (s2.polarity != state->polarity &&
372 state->duty_cycle < state->period)
373 dev_warn(chip->dev, ".apply ignored .polarity\n");
374
375 if (state->enabled &&
376 last->polarity == state->polarity &&
377 last->period > s2.period &&
378 last->period <= state->period)
379 dev_warn(chip->dev,
380 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
381 state->period, s2.period, last->period);
382
383 if (state->enabled && state->period < s2.period)
384 dev_warn(chip->dev,
385 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
386 state->period, s2.period);
387
388 if (state->enabled &&
389 last->polarity == state->polarity &&
390 last->period == s2.period &&
391 last->duty_cycle > s2.duty_cycle &&
392 last->duty_cycle <= state->duty_cycle)
393 dev_warn(chip->dev,
394 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
395 state->duty_cycle, state->period,
396 s2.duty_cycle, s2.period,
397 last->duty_cycle, last->period);
398
399 if (state->enabled && state->duty_cycle < s2.duty_cycle)
400 dev_warn(chip->dev,
401 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
402 state->duty_cycle, state->period,
403 s2.duty_cycle, s2.period);
404
405 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
406 dev_warn(chip->dev,
407 "requested disabled, but yielded enabled with duty > 0\n");
408
409 /* reapply the state that the driver reported being configured. */
410 err = chip->ops->apply(chip, pwm, &s1);
411 trace_pwm_apply(pwm, &s1, err);
412 if (err) {
413 *last = s1;
414 dev_err(chip->dev, "failed to reapply current setting\n");
415 return;
416 }
417
418 *last = (struct pwm_state){ 0 };
419 err = chip->ops->get_state(chip, pwm, last);
420 trace_pwm_get(pwm, last, err);
421 if (err)
422 return;
423
424 /* reapplication of the current state should give an exact match */
425 if (s1.enabled != last->enabled ||
426 s1.polarity != last->polarity ||
427 (s1.enabled && s1.period != last->period) ||
428 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
429 dev_err(chip->dev,
430 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
431 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
432 last->enabled, last->polarity, last->duty_cycle,
433 last->period);
434 }
435}
436
437/**
438 * __pwm_apply() - atomically apply a new state to a PWM device
439 * @pwm: PWM device
440 * @state: new state to apply
441 */
442static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
443{
444 struct pwm_chip *chip;
445 int err;
446
447 if (!pwm || !state || !state->period ||
448 state->duty_cycle > state->period)
449 return -EINVAL;
450
451 chip = pwm->chip;
452
453 if (state->period == pwm->state.period &&
454 state->duty_cycle == pwm->state.duty_cycle &&
455 state->polarity == pwm->state.polarity &&
456 state->enabled == pwm->state.enabled &&
457 state->usage_power == pwm->state.usage_power)
458 return 0;
459
460 err = chip->ops->apply(chip, pwm, state);
461 trace_pwm_apply(pwm, state, err);
462 if (err)
463 return err;
464
465 pwm->state = *state;
466
467 /*
468 * only do this after pwm->state was applied as some
469 * implementations of .get_state depend on this
470 */
471 pwm_apply_debug(pwm, state);
472
473 return 0;
474}
475
476/**
477 * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
478 * Cannot be used in atomic context.
479 * @pwm: PWM device
480 * @state: new state to apply
481 */
482int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
483{
484 int err;
485
486 /*
487 * Some lowlevel driver's implementations of .apply() make use of
488 * mutexes, also with some drivers only returning when the new
489 * configuration is active calling pwm_apply_might_sleep() from atomic context
490 * is a bad idea. So make it explicit that calling this function might
491 * sleep.
492 */
493 might_sleep();
494
495 if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
496 /*
497 * Catch any drivers that have been marked as atomic but
498 * that will sleep anyway.
499 */
500 non_block_start();
501 err = __pwm_apply(pwm, state);
502 non_block_end();
503 } else {
504 err = __pwm_apply(pwm, state);
505 }
506
507 return err;
508}
509EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);
510
511/**
512 * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
513 * Not all PWM devices support this function, check with pwm_might_sleep().
514 * @pwm: PWM device
515 * @state: new state to apply
516 */
517int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
518{
519 WARN_ONCE(!pwm->chip->atomic,
520 "sleeping PWM driver used in atomic context\n");
521
522 return __pwm_apply(pwm, state);
523}
524EXPORT_SYMBOL_GPL(pwm_apply_atomic);
525
526/**
527 * pwm_capture() - capture and report a PWM signal
528 * @pwm: PWM device
529 * @result: structure to fill with capture result
530 * @timeout: time to wait, in milliseconds, before giving up on capture
531 *
532 * Returns: 0 on success or a negative error code on failure.
533 */
534int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
535 unsigned long timeout)
536{
537 int err;
538
539 if (!pwm || !pwm->chip->ops)
540 return -EINVAL;
541
542 if (!pwm->chip->ops->capture)
543 return -ENOSYS;
544
545 mutex_lock(&pwm_lock);
546 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
547 mutex_unlock(&pwm_lock);
548
549 return err;
550}
551EXPORT_SYMBOL_GPL(pwm_capture);
552
553/**
554 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
555 * @pwm: PWM device
556 *
557 * This function will adjust the PWM config to the PWM arguments provided
558 * by the DT or PWM lookup table. This is particularly useful to adapt
559 * the bootloader config to the Linux one.
560 */
561int pwm_adjust_config(struct pwm_device *pwm)
562{
563 struct pwm_state state;
564 struct pwm_args pargs;
565
566 pwm_get_args(pwm, &pargs);
567 pwm_get_state(pwm, &state);
568
569 /*
570 * If the current period is zero it means that either the PWM driver
571 * does not support initial state retrieval or the PWM has not yet
572 * been configured.
573 *
574 * In either case, we setup the new period and polarity, and assign a
575 * duty cycle of 0.
576 */
577 if (!state.period) {
578 state.duty_cycle = 0;
579 state.period = pargs.period;
580 state.polarity = pargs.polarity;
581
582 return pwm_apply_might_sleep(pwm, &state);
583 }
584
585 /*
586 * Adjust the PWM duty cycle/period based on the period value provided
587 * in PWM args.
588 */
589 if (pargs.period != state.period) {
590 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
591
592 do_div(dutycycle, state.period);
593 state.duty_cycle = dutycycle;
594 state.period = pargs.period;
595 }
596
597 /*
598 * If the polarity changed, we should also change the duty cycle.
599 */
600 if (pargs.polarity != state.polarity) {
601 state.polarity = pargs.polarity;
602 state.duty_cycle = state.period - state.duty_cycle;
603 }
604
605 return pwm_apply_might_sleep(pwm, &state);
606}
607EXPORT_SYMBOL_GPL(pwm_adjust_config);
608
609static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
610{
611 struct pwm_chip *chip;
612 unsigned long id, tmp;
613
614 mutex_lock(&pwm_lock);
615
616 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
617 if (chip->dev && device_match_fwnode(chip->dev, fwnode)) {
618 mutex_unlock(&pwm_lock);
619 return chip;
620 }
621
622 mutex_unlock(&pwm_lock);
623
624 return ERR_PTR(-EPROBE_DEFER);
625}
626
627static struct device_link *pwm_device_link_add(struct device *dev,
628 struct pwm_device *pwm)
629{
630 struct device_link *dl;
631
632 if (!dev) {
633 /*
634 * No device for the PWM consumer has been provided. It may
635 * impact the PM sequence ordering: the PWM supplier may get
636 * suspended before the consumer.
637 */
638 dev_warn(pwm->chip->dev,
639 "No consumer device specified to create a link to\n");
640 return NULL;
641 }
642
643 dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
644 if (!dl) {
645 dev_err(dev, "failed to create device link to %s\n",
646 dev_name(pwm->chip->dev));
647 return ERR_PTR(-EINVAL);
648 }
649
650 return dl;
651}
652
653/**
654 * of_pwm_get() - request a PWM via the PWM framework
655 * @dev: device for PWM consumer
656 * @np: device node to get the PWM from
657 * @con_id: consumer name
658 *
659 * Returns the PWM device parsed from the phandle and index specified in the
660 * "pwms" property of a device tree node or a negative error-code on failure.
661 * Values parsed from the device tree are stored in the returned PWM device
662 * object.
663 *
664 * If con_id is NULL, the first PWM device listed in the "pwms" property will
665 * be requested. Otherwise the "pwm-names" property is used to do a reverse
666 * lookup of the PWM index. This also means that the "pwm-names" property
667 * becomes mandatory for devices that look up the PWM device via the con_id
668 * parameter.
669 *
670 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
671 * error code on failure.
672 */
673static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
674 const char *con_id)
675{
676 struct pwm_device *pwm = NULL;
677 struct of_phandle_args args;
678 struct device_link *dl;
679 struct pwm_chip *chip;
680 int index = 0;
681 int err;
682
683 if (con_id) {
684 index = of_property_match_string(np, "pwm-names", con_id);
685 if (index < 0)
686 return ERR_PTR(index);
687 }
688
689 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
690 &args);
691 if (err) {
692 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
693 return ERR_PTR(err);
694 }
695
696 chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
697 if (IS_ERR(chip)) {
698 if (PTR_ERR(chip) != -EPROBE_DEFER)
699 pr_err("%s(): PWM chip not found\n", __func__);
700
701 pwm = ERR_CAST(chip);
702 goto put;
703 }
704
705 pwm = chip->of_xlate(chip, &args);
706 if (IS_ERR(pwm))
707 goto put;
708
709 dl = pwm_device_link_add(dev, pwm);
710 if (IS_ERR(dl)) {
711 /* of_xlate ended up calling pwm_request_from_chip() */
712 pwm_put(pwm);
713 pwm = ERR_CAST(dl);
714 goto put;
715 }
716
717 /*
718 * If a consumer name was not given, try to look it up from the
719 * "pwm-names" property if it exists. Otherwise use the name of
720 * the user device node.
721 */
722 if (!con_id) {
723 err = of_property_read_string_index(np, "pwm-names", index,
724 &con_id);
725 if (err < 0)
726 con_id = np->name;
727 }
728
729 pwm->label = con_id;
730
731put:
732 of_node_put(args.np);
733
734 return pwm;
735}
736
737/**
738 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
739 * @fwnode: firmware node to get the "pwms" property from
740 *
741 * Returns the PWM device parsed from the fwnode and index specified in the
742 * "pwms" property or a negative error-code on failure.
743 * Values parsed from the device tree are stored in the returned PWM device
744 * object.
745 *
746 * This is analogous to of_pwm_get() except con_id is not yet supported.
747 * ACPI entries must look like
748 * Package () {"pwms", Package ()
749 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
750 *
751 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
752 * error code on failure.
753 */
754static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
755{
756 struct pwm_device *pwm;
757 struct fwnode_reference_args args;
758 struct pwm_chip *chip;
759 int ret;
760
761 memset(&args, 0, sizeof(args));
762
763 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
764 if (ret < 0)
765 return ERR_PTR(ret);
766
767 if (args.nargs < 2)
768 return ERR_PTR(-EPROTO);
769
770 chip = fwnode_to_pwmchip(args.fwnode);
771 if (IS_ERR(chip))
772 return ERR_CAST(chip);
773
774 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
775 if (IS_ERR(pwm))
776 return pwm;
777
778 pwm->args.period = args.args[1];
779 pwm->args.polarity = PWM_POLARITY_NORMAL;
780
781 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
782 pwm->args.polarity = PWM_POLARITY_INVERSED;
783
784 return pwm;
785}
786
787/**
788 * pwm_add_table() - register PWM device consumers
789 * @table: array of consumers to register
790 * @num: number of consumers in table
791 */
792void pwm_add_table(struct pwm_lookup *table, size_t num)
793{
794 mutex_lock(&pwm_lookup_lock);
795
796 while (num--) {
797 list_add_tail(&table->list, &pwm_lookup_list);
798 table++;
799 }
800
801 mutex_unlock(&pwm_lookup_lock);
802}
803
804/**
805 * pwm_remove_table() - unregister PWM device consumers
806 * @table: array of consumers to unregister
807 * @num: number of consumers in table
808 */
809void pwm_remove_table(struct pwm_lookup *table, size_t num)
810{
811 mutex_lock(&pwm_lookup_lock);
812
813 while (num--) {
814 list_del(&table->list);
815 table++;
816 }
817
818 mutex_unlock(&pwm_lookup_lock);
819}
820
821/**
822 * pwm_get() - look up and request a PWM device
823 * @dev: device for PWM consumer
824 * @con_id: consumer name
825 *
826 * Lookup is first attempted using DT. If the device was not instantiated from
827 * a device tree, a PWM chip and a relative index is looked up via a table
828 * supplied by board setup code (see pwm_add_table()).
829 *
830 * Once a PWM chip has been found the specified PWM device will be requested
831 * and is ready to be used.
832 *
833 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
834 * error code on failure.
835 */
836struct pwm_device *pwm_get(struct device *dev, const char *con_id)
837{
838 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
839 const char *dev_id = dev ? dev_name(dev) : NULL;
840 struct pwm_device *pwm;
841 struct pwm_chip *chip;
842 struct device_link *dl;
843 unsigned int best = 0;
844 struct pwm_lookup *p, *chosen = NULL;
845 unsigned int match;
846 int err;
847
848 /* look up via DT first */
849 if (is_of_node(fwnode))
850 return of_pwm_get(dev, to_of_node(fwnode), con_id);
851
852 /* then lookup via ACPI */
853 if (is_acpi_node(fwnode)) {
854 pwm = acpi_pwm_get(fwnode);
855 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
856 return pwm;
857 }
858
859 /*
860 * We look up the provider in the static table typically provided by
861 * board setup code. We first try to lookup the consumer device by
862 * name. If the consumer device was passed in as NULL or if no match
863 * was found, we try to find the consumer by directly looking it up
864 * by name.
865 *
866 * If a match is found, the provider PWM chip is looked up by name
867 * and a PWM device is requested using the PWM device per-chip index.
868 *
869 * The lookup algorithm was shamelessly taken from the clock
870 * framework:
871 *
872 * We do slightly fuzzy matching here:
873 * An entry with a NULL ID is assumed to be a wildcard.
874 * If an entry has a device ID, it must match
875 * If an entry has a connection ID, it must match
876 * Then we take the most specific entry - with the following order
877 * of precedence: dev+con > dev only > con only.
878 */
879 mutex_lock(&pwm_lookup_lock);
880
881 list_for_each_entry(p, &pwm_lookup_list, list) {
882 match = 0;
883
884 if (p->dev_id) {
885 if (!dev_id || strcmp(p->dev_id, dev_id))
886 continue;
887
888 match += 2;
889 }
890
891 if (p->con_id) {
892 if (!con_id || strcmp(p->con_id, con_id))
893 continue;
894
895 match += 1;
896 }
897
898 if (match > best) {
899 chosen = p;
900
901 if (match != 3)
902 best = match;
903 else
904 break;
905 }
906 }
907
908 mutex_unlock(&pwm_lookup_lock);
909
910 if (!chosen)
911 return ERR_PTR(-ENODEV);
912
913 chip = pwmchip_find_by_name(chosen->provider);
914
915 /*
916 * If the lookup entry specifies a module, load the module and retry
917 * the PWM chip lookup. This can be used to work around driver load
918 * ordering issues if driver's can't be made to properly support the
919 * deferred probe mechanism.
920 */
921 if (!chip && chosen->module) {
922 err = request_module(chosen->module);
923 if (err == 0)
924 chip = pwmchip_find_by_name(chosen->provider);
925 }
926
927 if (!chip)
928 return ERR_PTR(-EPROBE_DEFER);
929
930 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
931 if (IS_ERR(pwm))
932 return pwm;
933
934 dl = pwm_device_link_add(dev, pwm);
935 if (IS_ERR(dl)) {
936 pwm_put(pwm);
937 return ERR_CAST(dl);
938 }
939
940 pwm->args.period = chosen->period;
941 pwm->args.polarity = chosen->polarity;
942
943 return pwm;
944}
945EXPORT_SYMBOL_GPL(pwm_get);
946
947/**
948 * pwm_put() - release a PWM device
949 * @pwm: PWM device
950 */
951void pwm_put(struct pwm_device *pwm)
952{
953 if (!pwm)
954 return;
955
956 mutex_lock(&pwm_lock);
957
958 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
959 pr_warn("PWM device already freed\n");
960 goto out;
961 }
962
963 if (pwm->chip->ops->free)
964 pwm->chip->ops->free(pwm->chip, pwm);
965
966 pwm->label = NULL;
967
968 module_put(pwm->chip->owner);
969out:
970 mutex_unlock(&pwm_lock);
971}
972EXPORT_SYMBOL_GPL(pwm_put);
973
974static void devm_pwm_release(void *pwm)
975{
976 pwm_put(pwm);
977}
978
979/**
980 * devm_pwm_get() - resource managed pwm_get()
981 * @dev: device for PWM consumer
982 * @con_id: consumer name
983 *
984 * This function performs like pwm_get() but the acquired PWM device will
985 * automatically be released on driver detach.
986 *
987 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
988 * error code on failure.
989 */
990struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
991{
992 struct pwm_device *pwm;
993 int ret;
994
995 pwm = pwm_get(dev, con_id);
996 if (IS_ERR(pwm))
997 return pwm;
998
999 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1000 if (ret)
1001 return ERR_PTR(ret);
1002
1003 return pwm;
1004}
1005EXPORT_SYMBOL_GPL(devm_pwm_get);
1006
1007/**
1008 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1009 * @dev: device for PWM consumer
1010 * @fwnode: firmware node to get the PWM from
1011 * @con_id: consumer name
1012 *
1013 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1014 * acpi_pwm_get() for a detailed description.
1015 *
1016 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1017 * error code on failure.
1018 */
1019struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1020 struct fwnode_handle *fwnode,
1021 const char *con_id)
1022{
1023 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1024 int ret;
1025
1026 if (is_of_node(fwnode))
1027 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1028 else if (is_acpi_node(fwnode))
1029 pwm = acpi_pwm_get(fwnode);
1030 if (IS_ERR(pwm))
1031 return pwm;
1032
1033 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1034 if (ret)
1035 return ERR_PTR(ret);
1036
1037 return pwm;
1038}
1039EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1040
1041#ifdef CONFIG_DEBUG_FS
1042static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1043{
1044 unsigned int i;
1045
1046 for (i = 0; i < chip->npwm; i++) {
1047 struct pwm_device *pwm = &chip->pwms[i];
1048 struct pwm_state state;
1049
1050 pwm_get_state(pwm, &state);
1051
1052 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1053
1054 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1055 seq_puts(s, " requested");
1056
1057 if (state.enabled)
1058 seq_puts(s, " enabled");
1059
1060 seq_printf(s, " period: %llu ns", state.period);
1061 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1062 seq_printf(s, " polarity: %s",
1063 state.polarity ? "inverse" : "normal");
1064
1065 if (state.usage_power)
1066 seq_puts(s, " usage_power");
1067
1068 seq_puts(s, "\n");
1069 }
1070}
1071
1072static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1073{
1074 unsigned long id = *pos;
1075 void *ret;
1076
1077 mutex_lock(&pwm_lock);
1078 s->private = "";
1079
1080 ret = idr_get_next_ul(&pwm_chips, &id);
1081 *pos = id;
1082 return ret;
1083}
1084
1085static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1086{
1087 unsigned long id = *pos + 1;
1088 void *ret;
1089
1090 s->private = "\n";
1091
1092 ret = idr_get_next_ul(&pwm_chips, &id);
1093 *pos = id;
1094 return ret;
1095}
1096
1097static void pwm_seq_stop(struct seq_file *s, void *v)
1098{
1099 mutex_unlock(&pwm_lock);
1100}
1101
1102static int pwm_seq_show(struct seq_file *s, void *v)
1103{
1104 struct pwm_chip *chip = v;
1105
1106 seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n",
1107 (char *)s->private, chip->id,
1108 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1109 dev_name(chip->dev), chip->npwm,
1110 (chip->npwm != 1) ? "s" : "");
1111
1112 pwm_dbg_show(chip, s);
1113
1114 return 0;
1115}
1116
1117static const struct seq_operations pwm_debugfs_sops = {
1118 .start = pwm_seq_start,
1119 .next = pwm_seq_next,
1120 .stop = pwm_seq_stop,
1121 .show = pwm_seq_show,
1122};
1123
1124DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1125
1126static int __init pwm_debugfs_init(void)
1127{
1128 debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1129
1130 return 0;
1131}
1132subsys_initcall(pwm_debugfs_init);
1133#endif /* CONFIG_DEBUG_FS */
1/*
2 * Generic pwmlib implementation
3 *
4 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
5 * Copyright (C) 2011-2012 Avionic Design GmbH
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2, or (at your option)
10 * any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; see the file COPYING. If not, write to
19 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22#include <linux/module.h>
23#include <linux/pwm.h>
24#include <linux/radix-tree.h>
25#include <linux/list.h>
26#include <linux/mutex.h>
27#include <linux/err.h>
28#include <linux/slab.h>
29#include <linux/device.h>
30#include <linux/debugfs.h>
31#include <linux/seq_file.h>
32
33#include <dt-bindings/pwm/pwm.h>
34
35#define MAX_PWMS 1024
36
37static DEFINE_MUTEX(pwm_lookup_lock);
38static LIST_HEAD(pwm_lookup_list);
39static DEFINE_MUTEX(pwm_lock);
40static LIST_HEAD(pwm_chips);
41static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
42static RADIX_TREE(pwm_tree, GFP_KERNEL);
43
44static struct pwm_device *pwm_to_device(unsigned int pwm)
45{
46 return radix_tree_lookup(&pwm_tree, pwm);
47}
48
49static int alloc_pwms(int pwm, unsigned int count)
50{
51 unsigned int from = 0;
52 unsigned int start;
53
54 if (pwm >= MAX_PWMS)
55 return -EINVAL;
56
57 if (pwm >= 0)
58 from = pwm;
59
60 start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
61 count, 0);
62
63 if (pwm >= 0 && start != pwm)
64 return -EEXIST;
65
66 if (start + count > MAX_PWMS)
67 return -ENOSPC;
68
69 return start;
70}
71
72static void free_pwms(struct pwm_chip *chip)
73{
74 unsigned int i;
75
76 for (i = 0; i < chip->npwm; i++) {
77 struct pwm_device *pwm = &chip->pwms[i];
78
79 radix_tree_delete(&pwm_tree, pwm->pwm);
80 }
81
82 bitmap_clear(allocated_pwms, chip->base, chip->npwm);
83
84 kfree(chip->pwms);
85 chip->pwms = NULL;
86}
87
88static struct pwm_chip *pwmchip_find_by_name(const char *name)
89{
90 struct pwm_chip *chip;
91
92 if (!name)
93 return NULL;
94
95 mutex_lock(&pwm_lock);
96
97 list_for_each_entry(chip, &pwm_chips, list) {
98 const char *chip_name = dev_name(chip->dev);
99
100 if (chip_name && strcmp(chip_name, name) == 0) {
101 mutex_unlock(&pwm_lock);
102 return chip;
103 }
104 }
105
106 mutex_unlock(&pwm_lock);
107
108 return NULL;
109}
110
111static int pwm_device_request(struct pwm_device *pwm, const char *label)
112{
113 int err;
114
115 if (test_bit(PWMF_REQUESTED, &pwm->flags))
116 return -EBUSY;
117
118 if (!try_module_get(pwm->chip->ops->owner))
119 return -ENODEV;
120
121 if (pwm->chip->ops->request) {
122 err = pwm->chip->ops->request(pwm->chip, pwm);
123 if (err) {
124 module_put(pwm->chip->ops->owner);
125 return err;
126 }
127 }
128
129 set_bit(PWMF_REQUESTED, &pwm->flags);
130 pwm->label = label;
131
132 return 0;
133}
134
135struct pwm_device *
136of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
137{
138 struct pwm_device *pwm;
139
140 if (pc->of_pwm_n_cells < 3)
141 return ERR_PTR(-EINVAL);
142
143 if (args->args[0] >= pc->npwm)
144 return ERR_PTR(-EINVAL);
145
146 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
147 if (IS_ERR(pwm))
148 return pwm;
149
150 pwm->args.period = args->args[1];
151
152 if (args->args[2] & PWM_POLARITY_INVERTED)
153 pwm->args.polarity = PWM_POLARITY_INVERSED;
154 else
155 pwm->args.polarity = PWM_POLARITY_NORMAL;
156
157 return pwm;
158}
159EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
160
161static struct pwm_device *
162of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
163{
164 struct pwm_device *pwm;
165
166 if (pc->of_pwm_n_cells < 2)
167 return ERR_PTR(-EINVAL);
168
169 if (args->args[0] >= pc->npwm)
170 return ERR_PTR(-EINVAL);
171
172 pwm = pwm_request_from_chip(pc, args->args[0], NULL);
173 if (IS_ERR(pwm))
174 return pwm;
175
176 pwm->args.period = args->args[1];
177
178 return pwm;
179}
180
181static void of_pwmchip_add(struct pwm_chip *chip)
182{
183 if (!chip->dev || !chip->dev->of_node)
184 return;
185
186 if (!chip->of_xlate) {
187 chip->of_xlate = of_pwm_simple_xlate;
188 chip->of_pwm_n_cells = 2;
189 }
190
191 of_node_get(chip->dev->of_node);
192}
193
194static void of_pwmchip_remove(struct pwm_chip *chip)
195{
196 if (chip->dev)
197 of_node_put(chip->dev->of_node);
198}
199
200/**
201 * pwm_set_chip_data() - set private chip data for a PWM
202 * @pwm: PWM device
203 * @data: pointer to chip-specific data
204 *
205 * Returns: 0 on success or a negative error code on failure.
206 */
207int pwm_set_chip_data(struct pwm_device *pwm, void *data)
208{
209 if (!pwm)
210 return -EINVAL;
211
212 pwm->chip_data = data;
213
214 return 0;
215}
216EXPORT_SYMBOL_GPL(pwm_set_chip_data);
217
218/**
219 * pwm_get_chip_data() - get private chip data for a PWM
220 * @pwm: PWM device
221 *
222 * Returns: A pointer to the chip-private data for the PWM device.
223 */
224void *pwm_get_chip_data(struct pwm_device *pwm)
225{
226 return pwm ? pwm->chip_data : NULL;
227}
228EXPORT_SYMBOL_GPL(pwm_get_chip_data);
229
230static bool pwm_ops_check(const struct pwm_ops *ops)
231{
232 /* driver supports legacy, non-atomic operation */
233 if (ops->config && ops->enable && ops->disable)
234 return true;
235
236 /* driver supports atomic operation */
237 if (ops->apply)
238 return true;
239
240 return false;
241}
242
243/**
244 * pwmchip_add_with_polarity() - register a new PWM chip
245 * @chip: the PWM chip to add
246 * @polarity: initial polarity of PWM channels
247 *
248 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
249 * will be used. The initial polarity for all channels is specified by the
250 * @polarity parameter.
251 *
252 * Returns: 0 on success or a negative error code on failure.
253 */
254int pwmchip_add_with_polarity(struct pwm_chip *chip,
255 enum pwm_polarity polarity)
256{
257 struct pwm_device *pwm;
258 unsigned int i;
259 int ret;
260
261 if (!chip || !chip->dev || !chip->ops || !chip->npwm)
262 return -EINVAL;
263
264 if (!pwm_ops_check(chip->ops))
265 return -EINVAL;
266
267 mutex_lock(&pwm_lock);
268
269 ret = alloc_pwms(chip->base, chip->npwm);
270 if (ret < 0)
271 goto out;
272
273 chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
274 if (!chip->pwms) {
275 ret = -ENOMEM;
276 goto out;
277 }
278
279 chip->base = ret;
280
281 for (i = 0; i < chip->npwm; i++) {
282 pwm = &chip->pwms[i];
283
284 pwm->chip = chip;
285 pwm->pwm = chip->base + i;
286 pwm->hwpwm = i;
287 pwm->state.polarity = polarity;
288
289 if (chip->ops->get_state)
290 chip->ops->get_state(chip, pwm, &pwm->state);
291
292 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
293 }
294
295 bitmap_set(allocated_pwms, chip->base, chip->npwm);
296
297 INIT_LIST_HEAD(&chip->list);
298 list_add(&chip->list, &pwm_chips);
299
300 ret = 0;
301
302 if (IS_ENABLED(CONFIG_OF))
303 of_pwmchip_add(chip);
304
305 pwmchip_sysfs_export(chip);
306
307out:
308 mutex_unlock(&pwm_lock);
309 return ret;
310}
311EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
312
313/**
314 * pwmchip_add() - register a new PWM chip
315 * @chip: the PWM chip to add
316 *
317 * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
318 * will be used. The initial polarity for all channels is normal.
319 *
320 * Returns: 0 on success or a negative error code on failure.
321 */
322int pwmchip_add(struct pwm_chip *chip)
323{
324 return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
325}
326EXPORT_SYMBOL_GPL(pwmchip_add);
327
328/**
329 * pwmchip_remove() - remove a PWM chip
330 * @chip: the PWM chip to remove
331 *
332 * Removes a PWM chip. This function may return busy if the PWM chip provides
333 * a PWM device that is still requested.
334 *
335 * Returns: 0 on success or a negative error code on failure.
336 */
337int pwmchip_remove(struct pwm_chip *chip)
338{
339 unsigned int i;
340 int ret = 0;
341
342 pwmchip_sysfs_unexport_children(chip);
343
344 mutex_lock(&pwm_lock);
345
346 for (i = 0; i < chip->npwm; i++) {
347 struct pwm_device *pwm = &chip->pwms[i];
348
349 if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
350 ret = -EBUSY;
351 goto out;
352 }
353 }
354
355 list_del_init(&chip->list);
356
357 if (IS_ENABLED(CONFIG_OF))
358 of_pwmchip_remove(chip);
359
360 free_pwms(chip);
361
362 pwmchip_sysfs_unexport(chip);
363
364out:
365 mutex_unlock(&pwm_lock);
366 return ret;
367}
368EXPORT_SYMBOL_GPL(pwmchip_remove);
369
370/**
371 * pwm_request() - request a PWM device
372 * @pwm: global PWM device index
373 * @label: PWM device label
374 *
375 * This function is deprecated, use pwm_get() instead.
376 *
377 * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
378 * failure.
379 */
380struct pwm_device *pwm_request(int pwm, const char *label)
381{
382 struct pwm_device *dev;
383 int err;
384
385 if (pwm < 0 || pwm >= MAX_PWMS)
386 return ERR_PTR(-EINVAL);
387
388 mutex_lock(&pwm_lock);
389
390 dev = pwm_to_device(pwm);
391 if (!dev) {
392 dev = ERR_PTR(-EPROBE_DEFER);
393 goto out;
394 }
395
396 err = pwm_device_request(dev, label);
397 if (err < 0)
398 dev = ERR_PTR(err);
399
400out:
401 mutex_unlock(&pwm_lock);
402
403 return dev;
404}
405EXPORT_SYMBOL_GPL(pwm_request);
406
407/**
408 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
409 * @chip: PWM chip
410 * @index: per-chip index of the PWM to request
411 * @label: a literal description string of this PWM
412 *
413 * Returns: A pointer to the PWM device at the given index of the given PWM
414 * chip. A negative error code is returned if the index is not valid for the
415 * specified PWM chip or if the PWM device cannot be requested.
416 */
417struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
418 unsigned int index,
419 const char *label)
420{
421 struct pwm_device *pwm;
422 int err;
423
424 if (!chip || index >= chip->npwm)
425 return ERR_PTR(-EINVAL);
426
427 mutex_lock(&pwm_lock);
428 pwm = &chip->pwms[index];
429
430 err = pwm_device_request(pwm, label);
431 if (err < 0)
432 pwm = ERR_PTR(err);
433
434 mutex_unlock(&pwm_lock);
435 return pwm;
436}
437EXPORT_SYMBOL_GPL(pwm_request_from_chip);
438
439/**
440 * pwm_free() - free a PWM device
441 * @pwm: PWM device
442 *
443 * This function is deprecated, use pwm_put() instead.
444 */
445void pwm_free(struct pwm_device *pwm)
446{
447 pwm_put(pwm);
448}
449EXPORT_SYMBOL_GPL(pwm_free);
450
451/**
452 * pwm_apply_state() - atomically apply a new state to a PWM device
453 * @pwm: PWM device
454 * @state: new state to apply. This can be adjusted by the PWM driver
455 * if the requested config is not achievable, for example,
456 * ->duty_cycle and ->period might be approximated.
457 */
458int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
459{
460 int err;
461
462 if (!pwm || !state || !state->period ||
463 state->duty_cycle > state->period)
464 return -EINVAL;
465
466 if (!memcmp(state, &pwm->state, sizeof(*state)))
467 return 0;
468
469 if (pwm->chip->ops->apply) {
470 err = pwm->chip->ops->apply(pwm->chip, pwm, state);
471 if (err)
472 return err;
473
474 pwm->state = *state;
475 } else {
476 /*
477 * FIXME: restore the initial state in case of error.
478 */
479 if (state->polarity != pwm->state.polarity) {
480 if (!pwm->chip->ops->set_polarity)
481 return -ENOTSUPP;
482
483 /*
484 * Changing the polarity of a running PWM is
485 * only allowed when the PWM driver implements
486 * ->apply().
487 */
488 if (pwm->state.enabled) {
489 pwm->chip->ops->disable(pwm->chip, pwm);
490 pwm->state.enabled = false;
491 }
492
493 err = pwm->chip->ops->set_polarity(pwm->chip, pwm,
494 state->polarity);
495 if (err)
496 return err;
497
498 pwm->state.polarity = state->polarity;
499 }
500
501 if (state->period != pwm->state.period ||
502 state->duty_cycle != pwm->state.duty_cycle) {
503 err = pwm->chip->ops->config(pwm->chip, pwm,
504 state->duty_cycle,
505 state->period);
506 if (err)
507 return err;
508
509 pwm->state.duty_cycle = state->duty_cycle;
510 pwm->state.period = state->period;
511 }
512
513 if (state->enabled != pwm->state.enabled) {
514 if (state->enabled) {
515 err = pwm->chip->ops->enable(pwm->chip, pwm);
516 if (err)
517 return err;
518 } else {
519 pwm->chip->ops->disable(pwm->chip, pwm);
520 }
521
522 pwm->state.enabled = state->enabled;
523 }
524 }
525
526 return 0;
527}
528EXPORT_SYMBOL_GPL(pwm_apply_state);
529
530/**
531 * pwm_capture() - capture and report a PWM signal
532 * @pwm: PWM device
533 * @result: structure to fill with capture result
534 * @timeout: time to wait, in milliseconds, before giving up on capture
535 *
536 * Returns: 0 on success or a negative error code on failure.
537 */
538int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
539 unsigned long timeout)
540{
541 int err;
542
543 if (!pwm || !pwm->chip->ops)
544 return -EINVAL;
545
546 if (!pwm->chip->ops->capture)
547 return -ENOSYS;
548
549 mutex_lock(&pwm_lock);
550 err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
551 mutex_unlock(&pwm_lock);
552
553 return err;
554}
555EXPORT_SYMBOL_GPL(pwm_capture);
556
557/**
558 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
559 * @pwm: PWM device
560 *
561 * This function will adjust the PWM config to the PWM arguments provided
562 * by the DT or PWM lookup table. This is particularly useful to adapt
563 * the bootloader config to the Linux one.
564 */
565int pwm_adjust_config(struct pwm_device *pwm)
566{
567 struct pwm_state state;
568 struct pwm_args pargs;
569
570 pwm_get_args(pwm, &pargs);
571 pwm_get_state(pwm, &state);
572
573 /*
574 * If the current period is zero it means that either the PWM driver
575 * does not support initial state retrieval or the PWM has not yet
576 * been configured.
577 *
578 * In either case, we setup the new period and polarity, and assign a
579 * duty cycle of 0.
580 */
581 if (!state.period) {
582 state.duty_cycle = 0;
583 state.period = pargs.period;
584 state.polarity = pargs.polarity;
585
586 return pwm_apply_state(pwm, &state);
587 }
588
589 /*
590 * Adjust the PWM duty cycle/period based on the period value provided
591 * in PWM args.
592 */
593 if (pargs.period != state.period) {
594 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
595
596 do_div(dutycycle, state.period);
597 state.duty_cycle = dutycycle;
598 state.period = pargs.period;
599 }
600
601 /*
602 * If the polarity changed, we should also change the duty cycle.
603 */
604 if (pargs.polarity != state.polarity) {
605 state.polarity = pargs.polarity;
606 state.duty_cycle = state.period - state.duty_cycle;
607 }
608
609 return pwm_apply_state(pwm, &state);
610}
611EXPORT_SYMBOL_GPL(pwm_adjust_config);
612
613static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
614{
615 struct pwm_chip *chip;
616
617 mutex_lock(&pwm_lock);
618
619 list_for_each_entry(chip, &pwm_chips, list)
620 if (chip->dev && chip->dev->of_node == np) {
621 mutex_unlock(&pwm_lock);
622 return chip;
623 }
624
625 mutex_unlock(&pwm_lock);
626
627 return ERR_PTR(-EPROBE_DEFER);
628}
629
630/**
631 * of_pwm_get() - request a PWM via the PWM framework
632 * @np: device node to get the PWM from
633 * @con_id: consumer name
634 *
635 * Returns the PWM device parsed from the phandle and index specified in the
636 * "pwms" property of a device tree node or a negative error-code on failure.
637 * Values parsed from the device tree are stored in the returned PWM device
638 * object.
639 *
640 * If con_id is NULL, the first PWM device listed in the "pwms" property will
641 * be requested. Otherwise the "pwm-names" property is used to do a reverse
642 * lookup of the PWM index. This also means that the "pwm-names" property
643 * becomes mandatory for devices that look up the PWM device via the con_id
644 * parameter.
645 *
646 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
647 * error code on failure.
648 */
649struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
650{
651 struct pwm_device *pwm = NULL;
652 struct of_phandle_args args;
653 struct pwm_chip *pc;
654 int index = 0;
655 int err;
656
657 if (con_id) {
658 index = of_property_match_string(np, "pwm-names", con_id);
659 if (index < 0)
660 return ERR_PTR(index);
661 }
662
663 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
664 &args);
665 if (err) {
666 pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
667 return ERR_PTR(err);
668 }
669
670 pc = of_node_to_pwmchip(args.np);
671 if (IS_ERR(pc)) {
672 pr_debug("%s(): PWM chip not found\n", __func__);
673 pwm = ERR_CAST(pc);
674 goto put;
675 }
676
677 if (args.args_count != pc->of_pwm_n_cells) {
678 pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
679 args.np->full_name);
680 pwm = ERR_PTR(-EINVAL);
681 goto put;
682 }
683
684 pwm = pc->of_xlate(pc, &args);
685 if (IS_ERR(pwm))
686 goto put;
687
688 /*
689 * If a consumer name was not given, try to look it up from the
690 * "pwm-names" property if it exists. Otherwise use the name of
691 * the user device node.
692 */
693 if (!con_id) {
694 err = of_property_read_string_index(np, "pwm-names", index,
695 &con_id);
696 if (err < 0)
697 con_id = np->name;
698 }
699
700 pwm->label = con_id;
701
702put:
703 of_node_put(args.np);
704
705 return pwm;
706}
707EXPORT_SYMBOL_GPL(of_pwm_get);
708
709/**
710 * pwm_add_table() - register PWM device consumers
711 * @table: array of consumers to register
712 * @num: number of consumers in table
713 */
714void pwm_add_table(struct pwm_lookup *table, size_t num)
715{
716 mutex_lock(&pwm_lookup_lock);
717
718 while (num--) {
719 list_add_tail(&table->list, &pwm_lookup_list);
720 table++;
721 }
722
723 mutex_unlock(&pwm_lookup_lock);
724}
725
726/**
727 * pwm_remove_table() - unregister PWM device consumers
728 * @table: array of consumers to unregister
729 * @num: number of consumers in table
730 */
731void pwm_remove_table(struct pwm_lookup *table, size_t num)
732{
733 mutex_lock(&pwm_lookup_lock);
734
735 while (num--) {
736 list_del(&table->list);
737 table++;
738 }
739
740 mutex_unlock(&pwm_lookup_lock);
741}
742
743/**
744 * pwm_get() - look up and request a PWM device
745 * @dev: device for PWM consumer
746 * @con_id: consumer name
747 *
748 * Lookup is first attempted using DT. If the device was not instantiated from
749 * a device tree, a PWM chip and a relative index is looked up via a table
750 * supplied by board setup code (see pwm_add_table()).
751 *
752 * Once a PWM chip has been found the specified PWM device will be requested
753 * and is ready to be used.
754 *
755 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
756 * error code on failure.
757 */
758struct pwm_device *pwm_get(struct device *dev, const char *con_id)
759{
760 struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
761 const char *dev_id = dev ? dev_name(dev) : NULL;
762 struct pwm_chip *chip = NULL;
763 unsigned int best = 0;
764 struct pwm_lookup *p, *chosen = NULL;
765 unsigned int match;
766
767 /* look up via DT first */
768 if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
769 return of_pwm_get(dev->of_node, con_id);
770
771 /*
772 * We look up the provider in the static table typically provided by
773 * board setup code. We first try to lookup the consumer device by
774 * name. If the consumer device was passed in as NULL or if no match
775 * was found, we try to find the consumer by directly looking it up
776 * by name.
777 *
778 * If a match is found, the provider PWM chip is looked up by name
779 * and a PWM device is requested using the PWM device per-chip index.
780 *
781 * The lookup algorithm was shamelessly taken from the clock
782 * framework:
783 *
784 * We do slightly fuzzy matching here:
785 * An entry with a NULL ID is assumed to be a wildcard.
786 * If an entry has a device ID, it must match
787 * If an entry has a connection ID, it must match
788 * Then we take the most specific entry - with the following order
789 * of precedence: dev+con > dev only > con only.
790 */
791 mutex_lock(&pwm_lookup_lock);
792
793 list_for_each_entry(p, &pwm_lookup_list, list) {
794 match = 0;
795
796 if (p->dev_id) {
797 if (!dev_id || strcmp(p->dev_id, dev_id))
798 continue;
799
800 match += 2;
801 }
802
803 if (p->con_id) {
804 if (!con_id || strcmp(p->con_id, con_id))
805 continue;
806
807 match += 1;
808 }
809
810 if (match > best) {
811 chosen = p;
812
813 if (match != 3)
814 best = match;
815 else
816 break;
817 }
818 }
819
820 if (!chosen) {
821 pwm = ERR_PTR(-ENODEV);
822 goto out;
823 }
824
825 chip = pwmchip_find_by_name(chosen->provider);
826 if (!chip)
827 goto out;
828
829 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
830 if (IS_ERR(pwm))
831 goto out;
832
833 pwm->args.period = chosen->period;
834 pwm->args.polarity = chosen->polarity;
835
836out:
837 mutex_unlock(&pwm_lookup_lock);
838 return pwm;
839}
840EXPORT_SYMBOL_GPL(pwm_get);
841
842/**
843 * pwm_put() - release a PWM device
844 * @pwm: PWM device
845 */
846void pwm_put(struct pwm_device *pwm)
847{
848 if (!pwm)
849 return;
850
851 mutex_lock(&pwm_lock);
852
853 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
854 pr_warn("PWM device already freed\n");
855 goto out;
856 }
857
858 if (pwm->chip->ops->free)
859 pwm->chip->ops->free(pwm->chip, pwm);
860
861 pwm->label = NULL;
862
863 module_put(pwm->chip->ops->owner);
864out:
865 mutex_unlock(&pwm_lock);
866}
867EXPORT_SYMBOL_GPL(pwm_put);
868
869static void devm_pwm_release(struct device *dev, void *res)
870{
871 pwm_put(*(struct pwm_device **)res);
872}
873
874/**
875 * devm_pwm_get() - resource managed pwm_get()
876 * @dev: device for PWM consumer
877 * @con_id: consumer name
878 *
879 * This function performs like pwm_get() but the acquired PWM device will
880 * automatically be released on driver detach.
881 *
882 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
883 * error code on failure.
884 */
885struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
886{
887 struct pwm_device **ptr, *pwm;
888
889 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
890 if (!ptr)
891 return ERR_PTR(-ENOMEM);
892
893 pwm = pwm_get(dev, con_id);
894 if (!IS_ERR(pwm)) {
895 *ptr = pwm;
896 devres_add(dev, ptr);
897 } else {
898 devres_free(ptr);
899 }
900
901 return pwm;
902}
903EXPORT_SYMBOL_GPL(devm_pwm_get);
904
905/**
906 * devm_of_pwm_get() - resource managed of_pwm_get()
907 * @dev: device for PWM consumer
908 * @np: device node to get the PWM from
909 * @con_id: consumer name
910 *
911 * This function performs like of_pwm_get() but the acquired PWM device will
912 * automatically be released on driver detach.
913 *
914 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
915 * error code on failure.
916 */
917struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
918 const char *con_id)
919{
920 struct pwm_device **ptr, *pwm;
921
922 ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
923 if (!ptr)
924 return ERR_PTR(-ENOMEM);
925
926 pwm = of_pwm_get(np, con_id);
927 if (!IS_ERR(pwm)) {
928 *ptr = pwm;
929 devres_add(dev, ptr);
930 } else {
931 devres_free(ptr);
932 }
933
934 return pwm;
935}
936EXPORT_SYMBOL_GPL(devm_of_pwm_get);
937
938static int devm_pwm_match(struct device *dev, void *res, void *data)
939{
940 struct pwm_device **p = res;
941
942 if (WARN_ON(!p || !*p))
943 return 0;
944
945 return *p == data;
946}
947
948/**
949 * devm_pwm_put() - resource managed pwm_put()
950 * @dev: device for PWM consumer
951 * @pwm: PWM device
952 *
953 * Release a PWM previously allocated using devm_pwm_get(). Calling this
954 * function is usually not needed because devm-allocated resources are
955 * automatically released on driver detach.
956 */
957void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
958{
959 WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
960}
961EXPORT_SYMBOL_GPL(devm_pwm_put);
962
963/**
964 * pwm_can_sleep() - report whether PWM access will sleep
965 * @pwm: PWM device
966 *
967 * Returns: True if accessing the PWM can sleep, false otherwise.
968 */
969bool pwm_can_sleep(struct pwm_device *pwm)
970{
971 return true;
972}
973EXPORT_SYMBOL_GPL(pwm_can_sleep);
974
975#ifdef CONFIG_DEBUG_FS
976static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
977{
978 unsigned int i;
979
980 for (i = 0; i < chip->npwm; i++) {
981 struct pwm_device *pwm = &chip->pwms[i];
982 struct pwm_state state;
983
984 pwm_get_state(pwm, &state);
985
986 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
987
988 if (test_bit(PWMF_REQUESTED, &pwm->flags))
989 seq_puts(s, " requested");
990
991 if (state.enabled)
992 seq_puts(s, " enabled");
993
994 seq_printf(s, " period: %u ns", state.period);
995 seq_printf(s, " duty: %u ns", state.duty_cycle);
996 seq_printf(s, " polarity: %s",
997 state.polarity ? "inverse" : "normal");
998
999 seq_puts(s, "\n");
1000 }
1001}
1002
1003static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1004{
1005 mutex_lock(&pwm_lock);
1006 s->private = "";
1007
1008 return seq_list_start(&pwm_chips, *pos);
1009}
1010
1011static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1012{
1013 s->private = "\n";
1014
1015 return seq_list_next(v, &pwm_chips, pos);
1016}
1017
1018static void pwm_seq_stop(struct seq_file *s, void *v)
1019{
1020 mutex_unlock(&pwm_lock);
1021}
1022
1023static int pwm_seq_show(struct seq_file *s, void *v)
1024{
1025 struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
1026
1027 seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
1028 chip->dev->bus ? chip->dev->bus->name : "no-bus",
1029 dev_name(chip->dev), chip->npwm,
1030 (chip->npwm != 1) ? "s" : "");
1031
1032 if (chip->ops->dbg_show)
1033 chip->ops->dbg_show(chip, s);
1034 else
1035 pwm_dbg_show(chip, s);
1036
1037 return 0;
1038}
1039
1040static const struct seq_operations pwm_seq_ops = {
1041 .start = pwm_seq_start,
1042 .next = pwm_seq_next,
1043 .stop = pwm_seq_stop,
1044 .show = pwm_seq_show,
1045};
1046
1047static int pwm_seq_open(struct inode *inode, struct file *file)
1048{
1049 return seq_open(file, &pwm_seq_ops);
1050}
1051
1052static const struct file_operations pwm_debugfs_ops = {
1053 .owner = THIS_MODULE,
1054 .open = pwm_seq_open,
1055 .read = seq_read,
1056 .llseek = seq_lseek,
1057 .release = seq_release,
1058};
1059
1060static int __init pwm_debugfs_init(void)
1061{
1062 debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
1063 &pwm_debugfs_ops);
1064
1065 return 0;
1066}
1067subsys_initcall(pwm_debugfs_init);
1068#endif /* CONFIG_DEBUG_FS */