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 #define DEFAULT_SYMBOL_NAMESPACE PWM
10
11 #include <linux/acpi.h>
12 #include <linux/module.h>
13 #include <linux/idr.h>
14 #include <linux/of.h>
15 #include <linux/pwm.h>
16 #include <linux/list.h>
17 #include <linux/mutex.h>
18 #include <linux/err.h>
19 #include <linux/slab.h>
20 #include <linux/device.h>
21 #include <linux/debugfs.h>
22 #include <linux/seq_file.h>
23
24 #include <dt-bindings/pwm/pwm.h>
25
26 #define CREATE_TRACE_POINTS
27 #include <trace/events/pwm.h>
28
29 /* protects access to pwm_chips */
30 static DEFINE_MUTEX(pwm_lock);
31
32 static DEFINE_IDR(pwm_chips);
33
pwm_apply_debug(struct pwm_device * pwm,const struct pwm_state * state)34 static void pwm_apply_debug(struct pwm_device *pwm,
35 const struct pwm_state *state)
36 {
37 struct pwm_state *last = &pwm->last;
38 struct pwm_chip *chip = pwm->chip;
39 struct pwm_state s1 = { 0 }, s2 = { 0 };
40 int err;
41
42 if (!IS_ENABLED(CONFIG_PWM_DEBUG))
43 return;
44
45 /* No reasonable diagnosis possible without .get_state() */
46 if (!chip->ops->get_state)
47 return;
48
49 /*
50 * *state was just applied. Read out the hardware state and do some
51 * checks.
52 */
53
54 err = chip->ops->get_state(chip, pwm, &s1);
55 trace_pwm_get(pwm, &s1, err);
56 if (err)
57 /* If that failed there isn't much to debug */
58 return;
59
60 /*
61 * The lowlevel driver either ignored .polarity (which is a bug) or as
62 * best effort inverted .polarity and fixed .duty_cycle respectively.
63 * Undo this inversion and fixup for further tests.
64 */
65 if (s1.enabled && s1.polarity != state->polarity) {
66 s2.polarity = state->polarity;
67 s2.duty_cycle = s1.period - s1.duty_cycle;
68 s2.period = s1.period;
69 s2.enabled = s1.enabled;
70 } else {
71 s2 = s1;
72 }
73
74 if (s2.polarity != state->polarity &&
75 state->duty_cycle < state->period)
76 dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n");
77
78 if (state->enabled &&
79 last->polarity == state->polarity &&
80 last->period > s2.period &&
81 last->period <= state->period)
82 dev_warn(pwmchip_parent(chip),
83 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
84 state->period, s2.period, last->period);
85
86 if (state->enabled && state->period < s2.period)
87 dev_warn(pwmchip_parent(chip),
88 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
89 state->period, s2.period);
90
91 if (state->enabled &&
92 last->polarity == state->polarity &&
93 last->period == s2.period &&
94 last->duty_cycle > s2.duty_cycle &&
95 last->duty_cycle <= state->duty_cycle)
96 dev_warn(pwmchip_parent(chip),
97 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
98 state->duty_cycle, state->period,
99 s2.duty_cycle, s2.period,
100 last->duty_cycle, last->period);
101
102 if (state->enabled && state->duty_cycle < s2.duty_cycle)
103 dev_warn(pwmchip_parent(chip),
104 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
105 state->duty_cycle, state->period,
106 s2.duty_cycle, s2.period);
107
108 if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
109 dev_warn(pwmchip_parent(chip),
110 "requested disabled, but yielded enabled with duty > 0\n");
111
112 /* reapply the state that the driver reported being configured. */
113 err = chip->ops->apply(chip, pwm, &s1);
114 trace_pwm_apply(pwm, &s1, err);
115 if (err) {
116 *last = s1;
117 dev_err(pwmchip_parent(chip), "failed to reapply current setting\n");
118 return;
119 }
120
121 *last = (struct pwm_state){ 0 };
122 err = chip->ops->get_state(chip, pwm, last);
123 trace_pwm_get(pwm, last, err);
124 if (err)
125 return;
126
127 /* reapplication of the current state should give an exact match */
128 if (s1.enabled != last->enabled ||
129 s1.polarity != last->polarity ||
130 (s1.enabled && s1.period != last->period) ||
131 (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
132 dev_err(pwmchip_parent(chip),
133 ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
134 s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
135 last->enabled, last->polarity, last->duty_cycle,
136 last->period);
137 }
138 }
139
pwm_state_valid(const struct pwm_state * state)140 static bool pwm_state_valid(const struct pwm_state *state)
141 {
142 /*
143 * For a disabled state all other state description is irrelevant and
144 * and supposed to be ignored. So also ignore any strange values and
145 * consider the state ok.
146 */
147 if (state->enabled)
148 return true;
149
150 if (!state->period)
151 return false;
152
153 if (state->duty_cycle > state->period)
154 return false;
155
156 return true;
157 }
158
159 /**
160 * __pwm_apply() - atomically apply a new state to a PWM device
161 * @pwm: PWM device
162 * @state: new state to apply
163 */
__pwm_apply(struct pwm_device * pwm,const struct pwm_state * state)164 static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
165 {
166 struct pwm_chip *chip;
167 int err;
168
169 if (!pwm || !state)
170 return -EINVAL;
171
172 if (!pwm_state_valid(state)) {
173 /*
174 * Allow to transition from one invalid state to another.
175 * This ensures that you can e.g. change the polarity while
176 * the period is zero. (This happens on stm32 when the hardware
177 * is in its poweron default state.) This greatly simplifies
178 * working with the sysfs API where you can only change one
179 * parameter at a time.
180 */
181 if (!pwm_state_valid(&pwm->state)) {
182 pwm->state = *state;
183 return 0;
184 }
185
186 return -EINVAL;
187 }
188
189 chip = pwm->chip;
190
191 if (state->period == pwm->state.period &&
192 state->duty_cycle == pwm->state.duty_cycle &&
193 state->polarity == pwm->state.polarity &&
194 state->enabled == pwm->state.enabled &&
195 state->usage_power == pwm->state.usage_power)
196 return 0;
197
198 err = chip->ops->apply(chip, pwm, state);
199 trace_pwm_apply(pwm, state, err);
200 if (err)
201 return err;
202
203 pwm->state = *state;
204
205 /*
206 * only do this after pwm->state was applied as some
207 * implementations of .get_state depend on this
208 */
209 pwm_apply_debug(pwm, state);
210
211 return 0;
212 }
213
214 /**
215 * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
216 * Cannot be used in atomic context.
217 * @pwm: PWM device
218 * @state: new state to apply
219 */
pwm_apply_might_sleep(struct pwm_device * pwm,const struct pwm_state * state)220 int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
221 {
222 int err;
223
224 /*
225 * Some lowlevel driver's implementations of .apply() make use of
226 * mutexes, also with some drivers only returning when the new
227 * configuration is active calling pwm_apply_might_sleep() from atomic context
228 * is a bad idea. So make it explicit that calling this function might
229 * sleep.
230 */
231 might_sleep();
232
233 if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
234 /*
235 * Catch any drivers that have been marked as atomic but
236 * that will sleep anyway.
237 */
238 non_block_start();
239 err = __pwm_apply(pwm, state);
240 non_block_end();
241 } else {
242 err = __pwm_apply(pwm, state);
243 }
244
245 return err;
246 }
247 EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);
248
249 /**
250 * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
251 * Not all PWM devices support this function, check with pwm_might_sleep().
252 * @pwm: PWM device
253 * @state: new state to apply
254 */
pwm_apply_atomic(struct pwm_device * pwm,const struct pwm_state * state)255 int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
256 {
257 WARN_ONCE(!pwm->chip->atomic,
258 "sleeping PWM driver used in atomic context\n");
259
260 return __pwm_apply(pwm, state);
261 }
262 EXPORT_SYMBOL_GPL(pwm_apply_atomic);
263
264 /**
265 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
266 * @pwm: PWM device
267 *
268 * This function will adjust the PWM config to the PWM arguments provided
269 * by the DT or PWM lookup table. This is particularly useful to adapt
270 * the bootloader config to the Linux one.
271 */
pwm_adjust_config(struct pwm_device * pwm)272 int pwm_adjust_config(struct pwm_device *pwm)
273 {
274 struct pwm_state state;
275 struct pwm_args pargs;
276
277 pwm_get_args(pwm, &pargs);
278 pwm_get_state(pwm, &state);
279
280 /*
281 * If the current period is zero it means that either the PWM driver
282 * does not support initial state retrieval or the PWM has not yet
283 * been configured.
284 *
285 * In either case, we setup the new period and polarity, and assign a
286 * duty cycle of 0.
287 */
288 if (!state.period) {
289 state.duty_cycle = 0;
290 state.period = pargs.period;
291 state.polarity = pargs.polarity;
292
293 return pwm_apply_might_sleep(pwm, &state);
294 }
295
296 /*
297 * Adjust the PWM duty cycle/period based on the period value provided
298 * in PWM args.
299 */
300 if (pargs.period != state.period) {
301 u64 dutycycle = (u64)state.duty_cycle * pargs.period;
302
303 do_div(dutycycle, state.period);
304 state.duty_cycle = dutycycle;
305 state.period = pargs.period;
306 }
307
308 /*
309 * If the polarity changed, we should also change the duty cycle.
310 */
311 if (pargs.polarity != state.polarity) {
312 state.polarity = pargs.polarity;
313 state.duty_cycle = state.period - state.duty_cycle;
314 }
315
316 return pwm_apply_might_sleep(pwm, &state);
317 }
318 EXPORT_SYMBOL_GPL(pwm_adjust_config);
319
320 /**
321 * pwm_capture() - capture and report a PWM signal
322 * @pwm: PWM device
323 * @result: structure to fill with capture result
324 * @timeout: time to wait, in milliseconds, before giving up on capture
325 *
326 * Returns: 0 on success or a negative error code on failure.
327 */
pwm_capture(struct pwm_device * pwm,struct pwm_capture * result,unsigned long timeout)328 static int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
329 unsigned long timeout)
330 {
331 struct pwm_chip *chip = pwm->chip;
332 const struct pwm_ops *ops = chip->ops;
333
334 if (!ops->capture)
335 return -ENOSYS;
336
337 guard(mutex)(&pwm_lock);
338
339 return ops->capture(chip, pwm, result, timeout);
340 }
341
pwmchip_find_by_name(const char * name)342 static struct pwm_chip *pwmchip_find_by_name(const char *name)
343 {
344 struct pwm_chip *chip;
345 unsigned long id, tmp;
346
347 if (!name)
348 return NULL;
349
350 guard(mutex)(&pwm_lock);
351
352 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
353 const char *chip_name = dev_name(pwmchip_parent(chip));
354
355 if (chip_name && strcmp(chip_name, name) == 0)
356 return chip;
357 }
358
359 return NULL;
360 }
361
pwm_device_request(struct pwm_device * pwm,const char * label)362 static int pwm_device_request(struct pwm_device *pwm, const char *label)
363 {
364 int err;
365 struct pwm_chip *chip = pwm->chip;
366 const struct pwm_ops *ops = chip->ops;
367
368 if (test_bit(PWMF_REQUESTED, &pwm->flags))
369 return -EBUSY;
370
371 if (!try_module_get(chip->owner))
372 return -ENODEV;
373
374 if (!get_device(&chip->dev)) {
375 err = -ENODEV;
376 goto err_get_device;
377 }
378
379 if (ops->request) {
380 err = ops->request(chip, pwm);
381 if (err) {
382 put_device(&chip->dev);
383 err_get_device:
384 module_put(chip->owner);
385 return err;
386 }
387 }
388
389 if (ops->get_state) {
390 /*
391 * Zero-initialize state because most drivers are unaware of
392 * .usage_power. The other members of state are supposed to be
393 * set by lowlevel drivers. We still initialize the whole
394 * structure for simplicity even though this might paper over
395 * faulty implementations of .get_state().
396 */
397 struct pwm_state state = { 0, };
398
399 err = ops->get_state(chip, pwm, &state);
400 trace_pwm_get(pwm, &state, err);
401
402 if (!err)
403 pwm->state = state;
404
405 if (IS_ENABLED(CONFIG_PWM_DEBUG))
406 pwm->last = pwm->state;
407 }
408
409 set_bit(PWMF_REQUESTED, &pwm->flags);
410 pwm->label = label;
411
412 return 0;
413 }
414
415 /**
416 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
417 * @chip: PWM chip
418 * @index: per-chip index of the PWM to request
419 * @label: a literal description string of this PWM
420 *
421 * Returns: A pointer to the PWM device at the given index of the given PWM
422 * chip. A negative error code is returned if the index is not valid for the
423 * specified PWM chip or if the PWM device cannot be requested.
424 */
pwm_request_from_chip(struct pwm_chip * chip,unsigned int index,const char * label)425 static struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
426 unsigned int index,
427 const char *label)
428 {
429 struct pwm_device *pwm;
430 int err;
431
432 if (!chip || index >= chip->npwm)
433 return ERR_PTR(-EINVAL);
434
435 guard(mutex)(&pwm_lock);
436
437 pwm = &chip->pwms[index];
438
439 err = pwm_device_request(pwm, label);
440 if (err < 0)
441 return ERR_PTR(err);
442
443 return pwm;
444 }
445
446 struct pwm_device *
of_pwm_xlate_with_flags(struct pwm_chip * chip,const struct of_phandle_args * args)447 of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
448 {
449 struct pwm_device *pwm;
450
451 /* period in the second cell and flags in the third cell are optional */
452 if (args->args_count < 1)
453 return ERR_PTR(-EINVAL);
454
455 pwm = pwm_request_from_chip(chip, args->args[0], NULL);
456 if (IS_ERR(pwm))
457 return pwm;
458
459 if (args->args_count > 1)
460 pwm->args.period = args->args[1];
461
462 pwm->args.polarity = PWM_POLARITY_NORMAL;
463 if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
464 pwm->args.polarity = PWM_POLARITY_INVERSED;
465
466 return pwm;
467 }
468 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
469
470 struct pwm_device *
of_pwm_single_xlate(struct pwm_chip * chip,const struct of_phandle_args * args)471 of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
472 {
473 struct pwm_device *pwm;
474
475 pwm = pwm_request_from_chip(chip, 0, NULL);
476 if (IS_ERR(pwm))
477 return pwm;
478
479 if (args->args_count > 0)
480 pwm->args.period = args->args[0];
481
482 pwm->args.polarity = PWM_POLARITY_NORMAL;
483 if (args->args_count > 1 && args->args[1] & PWM_POLARITY_INVERTED)
484 pwm->args.polarity = PWM_POLARITY_INVERSED;
485
486 return pwm;
487 }
488 EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
489
490 struct pwm_export {
491 struct device pwm_dev;
492 struct pwm_device *pwm;
493 struct mutex lock;
494 struct pwm_state suspend;
495 };
496
pwmchip_from_dev(struct device * pwmchip_dev)497 static inline struct pwm_chip *pwmchip_from_dev(struct device *pwmchip_dev)
498 {
499 return container_of(pwmchip_dev, struct pwm_chip, dev);
500 }
501
pwmexport_from_dev(struct device * pwm_dev)502 static inline struct pwm_export *pwmexport_from_dev(struct device *pwm_dev)
503 {
504 return container_of(pwm_dev, struct pwm_export, pwm_dev);
505 }
506
pwm_from_dev(struct device * pwm_dev)507 static inline struct pwm_device *pwm_from_dev(struct device *pwm_dev)
508 {
509 struct pwm_export *export = pwmexport_from_dev(pwm_dev);
510
511 return export->pwm;
512 }
513
period_show(struct device * pwm_dev,struct device_attribute * attr,char * buf)514 static ssize_t period_show(struct device *pwm_dev,
515 struct device_attribute *attr,
516 char *buf)
517 {
518 const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
519 struct pwm_state state;
520
521 pwm_get_state(pwm, &state);
522
523 return sysfs_emit(buf, "%llu\n", state.period);
524 }
525
period_store(struct device * pwm_dev,struct device_attribute * attr,const char * buf,size_t size)526 static ssize_t period_store(struct device *pwm_dev,
527 struct device_attribute *attr,
528 const char *buf, size_t size)
529 {
530 struct pwm_export *export = pwmexport_from_dev(pwm_dev);
531 struct pwm_device *pwm = export->pwm;
532 struct pwm_state state;
533 u64 val;
534 int ret;
535
536 ret = kstrtou64(buf, 0, &val);
537 if (ret)
538 return ret;
539
540 guard(mutex)(&export->lock);
541
542 pwm_get_state(pwm, &state);
543 state.period = val;
544 ret = pwm_apply_might_sleep(pwm, &state);
545
546 return ret ? : size;
547 }
548
duty_cycle_show(struct device * pwm_dev,struct device_attribute * attr,char * buf)549 static ssize_t duty_cycle_show(struct device *pwm_dev,
550 struct device_attribute *attr,
551 char *buf)
552 {
553 const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
554 struct pwm_state state;
555
556 pwm_get_state(pwm, &state);
557
558 return sysfs_emit(buf, "%llu\n", state.duty_cycle);
559 }
560
duty_cycle_store(struct device * pwm_dev,struct device_attribute * attr,const char * buf,size_t size)561 static ssize_t duty_cycle_store(struct device *pwm_dev,
562 struct device_attribute *attr,
563 const char *buf, size_t size)
564 {
565 struct pwm_export *export = pwmexport_from_dev(pwm_dev);
566 struct pwm_device *pwm = export->pwm;
567 struct pwm_state state;
568 u64 val;
569 int ret;
570
571 ret = kstrtou64(buf, 0, &val);
572 if (ret)
573 return ret;
574
575 guard(mutex)(&export->lock);
576
577 pwm_get_state(pwm, &state);
578 state.duty_cycle = val;
579 ret = pwm_apply_might_sleep(pwm, &state);
580
581 return ret ? : size;
582 }
583
enable_show(struct device * pwm_dev,struct device_attribute * attr,char * buf)584 static ssize_t enable_show(struct device *pwm_dev,
585 struct device_attribute *attr,
586 char *buf)
587 {
588 const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
589 struct pwm_state state;
590
591 pwm_get_state(pwm, &state);
592
593 return sysfs_emit(buf, "%d\n", state.enabled);
594 }
595
enable_store(struct device * pwm_dev,struct device_attribute * attr,const char * buf,size_t size)596 static ssize_t enable_store(struct device *pwm_dev,
597 struct device_attribute *attr,
598 const char *buf, size_t size)
599 {
600 struct pwm_export *export = pwmexport_from_dev(pwm_dev);
601 struct pwm_device *pwm = export->pwm;
602 struct pwm_state state;
603 int val, ret;
604
605 ret = kstrtoint(buf, 0, &val);
606 if (ret)
607 return ret;
608
609 guard(mutex)(&export->lock);
610
611 pwm_get_state(pwm, &state);
612
613 switch (val) {
614 case 0:
615 state.enabled = false;
616 break;
617 case 1:
618 state.enabled = true;
619 break;
620 default:
621 return -EINVAL;
622 }
623
624 ret = pwm_apply_might_sleep(pwm, &state);
625
626 return ret ? : size;
627 }
628
polarity_show(struct device * pwm_dev,struct device_attribute * attr,char * buf)629 static ssize_t polarity_show(struct device *pwm_dev,
630 struct device_attribute *attr,
631 char *buf)
632 {
633 const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
634 const char *polarity = "unknown";
635 struct pwm_state state;
636
637 pwm_get_state(pwm, &state);
638
639 switch (state.polarity) {
640 case PWM_POLARITY_NORMAL:
641 polarity = "normal";
642 break;
643
644 case PWM_POLARITY_INVERSED:
645 polarity = "inversed";
646 break;
647 }
648
649 return sysfs_emit(buf, "%s\n", polarity);
650 }
651
polarity_store(struct device * pwm_dev,struct device_attribute * attr,const char * buf,size_t size)652 static ssize_t polarity_store(struct device *pwm_dev,
653 struct device_attribute *attr,
654 const char *buf, size_t size)
655 {
656 struct pwm_export *export = pwmexport_from_dev(pwm_dev);
657 struct pwm_device *pwm = export->pwm;
658 enum pwm_polarity polarity;
659 struct pwm_state state;
660 int ret;
661
662 if (sysfs_streq(buf, "normal"))
663 polarity = PWM_POLARITY_NORMAL;
664 else if (sysfs_streq(buf, "inversed"))
665 polarity = PWM_POLARITY_INVERSED;
666 else
667 return -EINVAL;
668
669 guard(mutex)(&export->lock);
670
671 pwm_get_state(pwm, &state);
672 state.polarity = polarity;
673 ret = pwm_apply_might_sleep(pwm, &state);
674
675 return ret ? : size;
676 }
677
capture_show(struct device * pwm_dev,struct device_attribute * attr,char * buf)678 static ssize_t capture_show(struct device *pwm_dev,
679 struct device_attribute *attr,
680 char *buf)
681 {
682 struct pwm_device *pwm = pwm_from_dev(pwm_dev);
683 struct pwm_capture result;
684 int ret;
685
686 ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
687 if (ret)
688 return ret;
689
690 return sysfs_emit(buf, "%u %u\n", result.period, result.duty_cycle);
691 }
692
693 static DEVICE_ATTR_RW(period);
694 static DEVICE_ATTR_RW(duty_cycle);
695 static DEVICE_ATTR_RW(enable);
696 static DEVICE_ATTR_RW(polarity);
697 static DEVICE_ATTR_RO(capture);
698
699 static struct attribute *pwm_attrs[] = {
700 &dev_attr_period.attr,
701 &dev_attr_duty_cycle.attr,
702 &dev_attr_enable.attr,
703 &dev_attr_polarity.attr,
704 &dev_attr_capture.attr,
705 NULL
706 };
707 ATTRIBUTE_GROUPS(pwm);
708
pwm_export_release(struct device * pwm_dev)709 static void pwm_export_release(struct device *pwm_dev)
710 {
711 struct pwm_export *export = pwmexport_from_dev(pwm_dev);
712
713 kfree(export);
714 }
715
pwm_export_child(struct device * pwmchip_dev,struct pwm_device * pwm)716 static int pwm_export_child(struct device *pwmchip_dev, struct pwm_device *pwm)
717 {
718 struct pwm_export *export;
719 char *pwm_prop[2];
720 int ret;
721
722 if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
723 return -EBUSY;
724
725 export = kzalloc(sizeof(*export), GFP_KERNEL);
726 if (!export) {
727 clear_bit(PWMF_EXPORTED, &pwm->flags);
728 return -ENOMEM;
729 }
730
731 export->pwm = pwm;
732 mutex_init(&export->lock);
733
734 export->pwm_dev.release = pwm_export_release;
735 export->pwm_dev.parent = pwmchip_dev;
736 export->pwm_dev.devt = MKDEV(0, 0);
737 export->pwm_dev.groups = pwm_groups;
738 dev_set_name(&export->pwm_dev, "pwm%u", pwm->hwpwm);
739
740 ret = device_register(&export->pwm_dev);
741 if (ret) {
742 clear_bit(PWMF_EXPORTED, &pwm->flags);
743 put_device(&export->pwm_dev);
744 export = NULL;
745 return ret;
746 }
747 pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
748 pwm_prop[1] = NULL;
749 kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
750 kfree(pwm_prop[0]);
751
752 return 0;
753 }
754
pwm_unexport_match(struct device * pwm_dev,void * data)755 static int pwm_unexport_match(struct device *pwm_dev, void *data)
756 {
757 return pwm_from_dev(pwm_dev) == data;
758 }
759
pwm_unexport_child(struct device * pwmchip_dev,struct pwm_device * pwm)760 static int pwm_unexport_child(struct device *pwmchip_dev, struct pwm_device *pwm)
761 {
762 struct device *pwm_dev;
763 char *pwm_prop[2];
764
765 if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
766 return -ENODEV;
767
768 pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
769 if (!pwm_dev)
770 return -ENODEV;
771
772 pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
773 pwm_prop[1] = NULL;
774 kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
775 kfree(pwm_prop[0]);
776
777 /* for device_find_child() */
778 put_device(pwm_dev);
779 device_unregister(pwm_dev);
780 pwm_put(pwm);
781
782 return 0;
783 }
784
export_store(struct device * pwmchip_dev,struct device_attribute * attr,const char * buf,size_t len)785 static ssize_t export_store(struct device *pwmchip_dev,
786 struct device_attribute *attr,
787 const char *buf, size_t len)
788 {
789 struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
790 struct pwm_device *pwm;
791 unsigned int hwpwm;
792 int ret;
793
794 ret = kstrtouint(buf, 0, &hwpwm);
795 if (ret < 0)
796 return ret;
797
798 if (hwpwm >= chip->npwm)
799 return -ENODEV;
800
801 pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
802 if (IS_ERR(pwm))
803 return PTR_ERR(pwm);
804
805 ret = pwm_export_child(pwmchip_dev, pwm);
806 if (ret < 0)
807 pwm_put(pwm);
808
809 return ret ? : len;
810 }
811 static DEVICE_ATTR_WO(export);
812
unexport_store(struct device * pwmchip_dev,struct device_attribute * attr,const char * buf,size_t len)813 static ssize_t unexport_store(struct device *pwmchip_dev,
814 struct device_attribute *attr,
815 const char *buf, size_t len)
816 {
817 struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
818 unsigned int hwpwm;
819 int ret;
820
821 ret = kstrtouint(buf, 0, &hwpwm);
822 if (ret < 0)
823 return ret;
824
825 if (hwpwm >= chip->npwm)
826 return -ENODEV;
827
828 ret = pwm_unexport_child(pwmchip_dev, &chip->pwms[hwpwm]);
829
830 return ret ? : len;
831 }
832 static DEVICE_ATTR_WO(unexport);
833
npwm_show(struct device * pwmchip_dev,struct device_attribute * attr,char * buf)834 static ssize_t npwm_show(struct device *pwmchip_dev, struct device_attribute *attr,
835 char *buf)
836 {
837 const struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
838
839 return sysfs_emit(buf, "%u\n", chip->npwm);
840 }
841 static DEVICE_ATTR_RO(npwm);
842
843 static struct attribute *pwm_chip_attrs[] = {
844 &dev_attr_export.attr,
845 &dev_attr_unexport.attr,
846 &dev_attr_npwm.attr,
847 NULL,
848 };
849 ATTRIBUTE_GROUPS(pwm_chip);
850
851 /* takes export->lock on success */
pwm_class_get_state(struct device * pwmchip_dev,struct pwm_device * pwm,struct pwm_state * state)852 static struct pwm_export *pwm_class_get_state(struct device *pwmchip_dev,
853 struct pwm_device *pwm,
854 struct pwm_state *state)
855 {
856 struct device *pwm_dev;
857 struct pwm_export *export;
858
859 if (!test_bit(PWMF_EXPORTED, &pwm->flags))
860 return NULL;
861
862 pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
863 if (!pwm_dev)
864 return NULL;
865
866 export = pwmexport_from_dev(pwm_dev);
867 put_device(pwm_dev); /* for device_find_child() */
868
869 mutex_lock(&export->lock);
870 pwm_get_state(pwm, state);
871
872 return export;
873 }
874
pwm_class_apply_state(struct pwm_export * export,struct pwm_device * pwm,struct pwm_state * state)875 static int pwm_class_apply_state(struct pwm_export *export,
876 struct pwm_device *pwm,
877 struct pwm_state *state)
878 {
879 int ret = pwm_apply_might_sleep(pwm, state);
880
881 /* release lock taken in pwm_class_get_state */
882 mutex_unlock(&export->lock);
883
884 return ret;
885 }
886
pwm_class_resume_npwm(struct device * pwmchip_dev,unsigned int npwm)887 static int pwm_class_resume_npwm(struct device *pwmchip_dev, unsigned int npwm)
888 {
889 struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
890 unsigned int i;
891 int ret = 0;
892
893 for (i = 0; i < npwm; i++) {
894 struct pwm_device *pwm = &chip->pwms[i];
895 struct pwm_state state;
896 struct pwm_export *export;
897
898 export = pwm_class_get_state(pwmchip_dev, pwm, &state);
899 if (!export)
900 continue;
901
902 /* If pwmchip was not enabled before suspend, do nothing. */
903 if (!export->suspend.enabled) {
904 /* release lock taken in pwm_class_get_state */
905 mutex_unlock(&export->lock);
906 continue;
907 }
908
909 state.enabled = export->suspend.enabled;
910 ret = pwm_class_apply_state(export, pwm, &state);
911 if (ret < 0)
912 break;
913 }
914
915 return ret;
916 }
917
pwm_class_suspend(struct device * pwmchip_dev)918 static int pwm_class_suspend(struct device *pwmchip_dev)
919 {
920 struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
921 unsigned int i;
922 int ret = 0;
923
924 for (i = 0; i < chip->npwm; i++) {
925 struct pwm_device *pwm = &chip->pwms[i];
926 struct pwm_state state;
927 struct pwm_export *export;
928
929 export = pwm_class_get_state(pwmchip_dev, pwm, &state);
930 if (!export)
931 continue;
932
933 /*
934 * If pwmchip was not enabled before suspend, save
935 * state for resume time and do nothing else.
936 */
937 export->suspend = state;
938 if (!state.enabled) {
939 /* release lock taken in pwm_class_get_state */
940 mutex_unlock(&export->lock);
941 continue;
942 }
943
944 state.enabled = false;
945 ret = pwm_class_apply_state(export, pwm, &state);
946 if (ret < 0) {
947 /*
948 * roll back the PWM devices that were disabled by
949 * this suspend function.
950 */
951 pwm_class_resume_npwm(pwmchip_dev, i);
952 break;
953 }
954 }
955
956 return ret;
957 }
958
pwm_class_resume(struct device * pwmchip_dev)959 static int pwm_class_resume(struct device *pwmchip_dev)
960 {
961 struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
962
963 return pwm_class_resume_npwm(pwmchip_dev, chip->npwm);
964 }
965
966 static DEFINE_SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
967
968 static struct class pwm_class = {
969 .name = "pwm",
970 .dev_groups = pwm_chip_groups,
971 .pm = pm_sleep_ptr(&pwm_class_pm_ops),
972 };
973
pwmchip_sysfs_unexport(struct pwm_chip * chip)974 static void pwmchip_sysfs_unexport(struct pwm_chip *chip)
975 {
976 unsigned int i;
977
978 for (i = 0; i < chip->npwm; i++) {
979 struct pwm_device *pwm = &chip->pwms[i];
980
981 if (test_bit(PWMF_EXPORTED, &pwm->flags))
982 pwm_unexport_child(&chip->dev, pwm);
983 }
984 }
985
986 #define PWMCHIP_ALIGN ARCH_DMA_MINALIGN
987
pwmchip_priv(struct pwm_chip * chip)988 static void *pwmchip_priv(struct pwm_chip *chip)
989 {
990 return (void *)chip + ALIGN(struct_size(chip, pwms, chip->npwm), PWMCHIP_ALIGN);
991 }
992
993 /* This is the counterpart to pwmchip_alloc() */
pwmchip_put(struct pwm_chip * chip)994 void pwmchip_put(struct pwm_chip *chip)
995 {
996 put_device(&chip->dev);
997 }
998 EXPORT_SYMBOL_GPL(pwmchip_put);
999
pwmchip_release(struct device * pwmchip_dev)1000 static void pwmchip_release(struct device *pwmchip_dev)
1001 {
1002 struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
1003
1004 kfree(chip);
1005 }
1006
pwmchip_alloc(struct device * parent,unsigned int npwm,size_t sizeof_priv)1007 struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
1008 {
1009 struct pwm_chip *chip;
1010 struct device *pwmchip_dev;
1011 size_t alloc_size;
1012 unsigned int i;
1013
1014 alloc_size = size_add(ALIGN(struct_size(chip, pwms, npwm), PWMCHIP_ALIGN),
1015 sizeof_priv);
1016
1017 chip = kzalloc(alloc_size, GFP_KERNEL);
1018 if (!chip)
1019 return ERR_PTR(-ENOMEM);
1020
1021 chip->npwm = npwm;
1022 chip->uses_pwmchip_alloc = true;
1023
1024 pwmchip_dev = &chip->dev;
1025 device_initialize(pwmchip_dev);
1026 pwmchip_dev->class = &pwm_class;
1027 pwmchip_dev->parent = parent;
1028 pwmchip_dev->release = pwmchip_release;
1029
1030 pwmchip_set_drvdata(chip, pwmchip_priv(chip));
1031
1032 for (i = 0; i < chip->npwm; i++) {
1033 struct pwm_device *pwm = &chip->pwms[i];
1034 pwm->chip = chip;
1035 pwm->hwpwm = i;
1036 }
1037
1038 return chip;
1039 }
1040 EXPORT_SYMBOL_GPL(pwmchip_alloc);
1041
devm_pwmchip_put(void * data)1042 static void devm_pwmchip_put(void *data)
1043 {
1044 struct pwm_chip *chip = data;
1045
1046 pwmchip_put(chip);
1047 }
1048
devm_pwmchip_alloc(struct device * parent,unsigned int npwm,size_t sizeof_priv)1049 struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
1050 {
1051 struct pwm_chip *chip;
1052 int ret;
1053
1054 chip = pwmchip_alloc(parent, npwm, sizeof_priv);
1055 if (IS_ERR(chip))
1056 return chip;
1057
1058 ret = devm_add_action_or_reset(parent, devm_pwmchip_put, chip);
1059 if (ret)
1060 return ERR_PTR(ret);
1061
1062 return chip;
1063 }
1064 EXPORT_SYMBOL_GPL(devm_pwmchip_alloc);
1065
of_pwmchip_add(struct pwm_chip * chip)1066 static void of_pwmchip_add(struct pwm_chip *chip)
1067 {
1068 if (!pwmchip_parent(chip) || !pwmchip_parent(chip)->of_node)
1069 return;
1070
1071 if (!chip->of_xlate)
1072 chip->of_xlate = of_pwm_xlate_with_flags;
1073
1074 of_node_get(pwmchip_parent(chip)->of_node);
1075 }
1076
of_pwmchip_remove(struct pwm_chip * chip)1077 static void of_pwmchip_remove(struct pwm_chip *chip)
1078 {
1079 if (pwmchip_parent(chip))
1080 of_node_put(pwmchip_parent(chip)->of_node);
1081 }
1082
pwm_ops_check(const struct pwm_chip * chip)1083 static bool pwm_ops_check(const struct pwm_chip *chip)
1084 {
1085 const struct pwm_ops *ops = chip->ops;
1086
1087 if (!ops->apply)
1088 return false;
1089
1090 if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
1091 dev_warn(pwmchip_parent(chip),
1092 "Please implement the .get_state() callback\n");
1093
1094 return true;
1095 }
1096
1097 /**
1098 * __pwmchip_add() - register a new PWM chip
1099 * @chip: the PWM chip to add
1100 * @owner: reference to the module providing the chip.
1101 *
1102 * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
1103 * pwmchip_add wrapper to do this right.
1104 *
1105 * Returns: 0 on success or a negative error code on failure.
1106 */
__pwmchip_add(struct pwm_chip * chip,struct module * owner)1107 int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
1108 {
1109 int ret;
1110
1111 if (!chip || !pwmchip_parent(chip) || !chip->ops || !chip->npwm)
1112 return -EINVAL;
1113
1114 /*
1115 * a struct pwm_chip must be allocated using (devm_)pwmchip_alloc,
1116 * otherwise the embedded struct device might disappear too early
1117 * resulting in memory corruption.
1118 * Catch drivers that were not converted appropriately.
1119 */
1120 if (!chip->uses_pwmchip_alloc)
1121 return -EINVAL;
1122
1123 if (!pwm_ops_check(chip))
1124 return -EINVAL;
1125
1126 chip->owner = owner;
1127
1128 guard(mutex)(&pwm_lock);
1129
1130 ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
1131 if (ret < 0)
1132 return ret;
1133
1134 chip->id = ret;
1135
1136 dev_set_name(&chip->dev, "pwmchip%u", chip->id);
1137
1138 if (IS_ENABLED(CONFIG_OF))
1139 of_pwmchip_add(chip);
1140
1141 ret = device_add(&chip->dev);
1142 if (ret)
1143 goto err_device_add;
1144
1145 return 0;
1146
1147 err_device_add:
1148 if (IS_ENABLED(CONFIG_OF))
1149 of_pwmchip_remove(chip);
1150
1151 idr_remove(&pwm_chips, chip->id);
1152
1153 return ret;
1154 }
1155 EXPORT_SYMBOL_GPL(__pwmchip_add);
1156
1157 /**
1158 * pwmchip_remove() - remove a PWM chip
1159 * @chip: the PWM chip to remove
1160 *
1161 * Removes a PWM chip.
1162 */
pwmchip_remove(struct pwm_chip * chip)1163 void pwmchip_remove(struct pwm_chip *chip)
1164 {
1165 pwmchip_sysfs_unexport(chip);
1166
1167 if (IS_ENABLED(CONFIG_OF))
1168 of_pwmchip_remove(chip);
1169
1170 scoped_guard(mutex, &pwm_lock)
1171 idr_remove(&pwm_chips, chip->id);
1172
1173 device_del(&chip->dev);
1174 }
1175 EXPORT_SYMBOL_GPL(pwmchip_remove);
1176
devm_pwmchip_remove(void * data)1177 static void devm_pwmchip_remove(void *data)
1178 {
1179 struct pwm_chip *chip = data;
1180
1181 pwmchip_remove(chip);
1182 }
1183
__devm_pwmchip_add(struct device * dev,struct pwm_chip * chip,struct module * owner)1184 int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
1185 {
1186 int ret;
1187
1188 ret = __pwmchip_add(chip, owner);
1189 if (ret)
1190 return ret;
1191
1192 return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
1193 }
1194 EXPORT_SYMBOL_GPL(__devm_pwmchip_add);
1195
pwm_device_link_add(struct device * dev,struct pwm_device * pwm)1196 static struct device_link *pwm_device_link_add(struct device *dev,
1197 struct pwm_device *pwm)
1198 {
1199 struct device_link *dl;
1200
1201 if (!dev) {
1202 /*
1203 * No device for the PWM consumer has been provided. It may
1204 * impact the PM sequence ordering: the PWM supplier may get
1205 * suspended before the consumer.
1206 */
1207 dev_warn(pwmchip_parent(pwm->chip),
1208 "No consumer device specified to create a link to\n");
1209 return NULL;
1210 }
1211
1212 dl = device_link_add(dev, pwmchip_parent(pwm->chip), DL_FLAG_AUTOREMOVE_CONSUMER);
1213 if (!dl) {
1214 dev_err(dev, "failed to create device link to %s\n",
1215 dev_name(pwmchip_parent(pwm->chip)));
1216 return ERR_PTR(-EINVAL);
1217 }
1218
1219 return dl;
1220 }
1221
fwnode_to_pwmchip(struct fwnode_handle * fwnode)1222 static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
1223 {
1224 struct pwm_chip *chip;
1225 unsigned long id, tmp;
1226
1227 guard(mutex)(&pwm_lock);
1228
1229 idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
1230 if (pwmchip_parent(chip) && device_match_fwnode(pwmchip_parent(chip), fwnode))
1231 return chip;
1232
1233 return ERR_PTR(-EPROBE_DEFER);
1234 }
1235
1236 /**
1237 * of_pwm_get() - request a PWM via the PWM framework
1238 * @dev: device for PWM consumer
1239 * @np: device node to get the PWM from
1240 * @con_id: consumer name
1241 *
1242 * Returns the PWM device parsed from the phandle and index specified in the
1243 * "pwms" property of a device tree node or a negative error-code on failure.
1244 * Values parsed from the device tree are stored in the returned PWM device
1245 * object.
1246 *
1247 * If con_id is NULL, the first PWM device listed in the "pwms" property will
1248 * be requested. Otherwise the "pwm-names" property is used to do a reverse
1249 * lookup of the PWM index. This also means that the "pwm-names" property
1250 * becomes mandatory for devices that look up the PWM device via the con_id
1251 * parameter.
1252 *
1253 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1254 * error code on failure.
1255 */
of_pwm_get(struct device * dev,struct device_node * np,const char * con_id)1256 static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
1257 const char *con_id)
1258 {
1259 struct pwm_device *pwm = NULL;
1260 struct of_phandle_args args;
1261 struct device_link *dl;
1262 struct pwm_chip *chip;
1263 int index = 0;
1264 int err;
1265
1266 if (con_id) {
1267 index = of_property_match_string(np, "pwm-names", con_id);
1268 if (index < 0)
1269 return ERR_PTR(index);
1270 }
1271
1272 err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
1273 &args);
1274 if (err) {
1275 pr_err("%s(): can't parse \"pwms\" property\n", __func__);
1276 return ERR_PTR(err);
1277 }
1278
1279 chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
1280 if (IS_ERR(chip)) {
1281 if (PTR_ERR(chip) != -EPROBE_DEFER)
1282 pr_err("%s(): PWM chip not found\n", __func__);
1283
1284 pwm = ERR_CAST(chip);
1285 goto put;
1286 }
1287
1288 pwm = chip->of_xlate(chip, &args);
1289 if (IS_ERR(pwm))
1290 goto put;
1291
1292 dl = pwm_device_link_add(dev, pwm);
1293 if (IS_ERR(dl)) {
1294 /* of_xlate ended up calling pwm_request_from_chip() */
1295 pwm_put(pwm);
1296 pwm = ERR_CAST(dl);
1297 goto put;
1298 }
1299
1300 /*
1301 * If a consumer name was not given, try to look it up from the
1302 * "pwm-names" property if it exists. Otherwise use the name of
1303 * the user device node.
1304 */
1305 if (!con_id) {
1306 err = of_property_read_string_index(np, "pwm-names", index,
1307 &con_id);
1308 if (err < 0)
1309 con_id = np->name;
1310 }
1311
1312 pwm->label = con_id;
1313
1314 put:
1315 of_node_put(args.np);
1316
1317 return pwm;
1318 }
1319
1320 /**
1321 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
1322 * @fwnode: firmware node to get the "pwms" property from
1323 *
1324 * Returns the PWM device parsed from the fwnode and index specified in the
1325 * "pwms" property or a negative error-code on failure.
1326 * Values parsed from the device tree are stored in the returned PWM device
1327 * object.
1328 *
1329 * This is analogous to of_pwm_get() except con_id is not yet supported.
1330 * ACPI entries must look like
1331 * Package () {"pwms", Package ()
1332 * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
1333 *
1334 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1335 * error code on failure.
1336 */
acpi_pwm_get(const struct fwnode_handle * fwnode)1337 static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
1338 {
1339 struct pwm_device *pwm;
1340 struct fwnode_reference_args args;
1341 struct pwm_chip *chip;
1342 int ret;
1343
1344 memset(&args, 0, sizeof(args));
1345
1346 ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
1347 if (ret < 0)
1348 return ERR_PTR(ret);
1349
1350 if (args.nargs < 2)
1351 return ERR_PTR(-EPROTO);
1352
1353 chip = fwnode_to_pwmchip(args.fwnode);
1354 if (IS_ERR(chip))
1355 return ERR_CAST(chip);
1356
1357 pwm = pwm_request_from_chip(chip, args.args[0], NULL);
1358 if (IS_ERR(pwm))
1359 return pwm;
1360
1361 pwm->args.period = args.args[1];
1362 pwm->args.polarity = PWM_POLARITY_NORMAL;
1363
1364 if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
1365 pwm->args.polarity = PWM_POLARITY_INVERSED;
1366
1367 return pwm;
1368 }
1369
1370 static DEFINE_MUTEX(pwm_lookup_lock);
1371 static LIST_HEAD(pwm_lookup_list);
1372
1373 /**
1374 * pwm_add_table() - register PWM device consumers
1375 * @table: array of consumers to register
1376 * @num: number of consumers in table
1377 */
pwm_add_table(struct pwm_lookup * table,size_t num)1378 void pwm_add_table(struct pwm_lookup *table, size_t num)
1379 {
1380 guard(mutex)(&pwm_lookup_lock);
1381
1382 while (num--) {
1383 list_add_tail(&table->list, &pwm_lookup_list);
1384 table++;
1385 }
1386 }
1387
1388 /**
1389 * pwm_remove_table() - unregister PWM device consumers
1390 * @table: array of consumers to unregister
1391 * @num: number of consumers in table
1392 */
pwm_remove_table(struct pwm_lookup * table,size_t num)1393 void pwm_remove_table(struct pwm_lookup *table, size_t num)
1394 {
1395 guard(mutex)(&pwm_lookup_lock);
1396
1397 while (num--) {
1398 list_del(&table->list);
1399 table++;
1400 }
1401 }
1402
1403 /**
1404 * pwm_get() - look up and request a PWM device
1405 * @dev: device for PWM consumer
1406 * @con_id: consumer name
1407 *
1408 * Lookup is first attempted using DT. If the device was not instantiated from
1409 * a device tree, a PWM chip and a relative index is looked up via a table
1410 * supplied by board setup code (see pwm_add_table()).
1411 *
1412 * Once a PWM chip has been found the specified PWM device will be requested
1413 * and is ready to be used.
1414 *
1415 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1416 * error code on failure.
1417 */
pwm_get(struct device * dev,const char * con_id)1418 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
1419 {
1420 const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
1421 const char *dev_id = dev ? dev_name(dev) : NULL;
1422 struct pwm_device *pwm;
1423 struct pwm_chip *chip;
1424 struct device_link *dl;
1425 unsigned int best = 0;
1426 struct pwm_lookup *p, *chosen = NULL;
1427 unsigned int match;
1428 int err;
1429
1430 /* look up via DT first */
1431 if (is_of_node(fwnode))
1432 return of_pwm_get(dev, to_of_node(fwnode), con_id);
1433
1434 /* then lookup via ACPI */
1435 if (is_acpi_node(fwnode)) {
1436 pwm = acpi_pwm_get(fwnode);
1437 if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
1438 return pwm;
1439 }
1440
1441 /*
1442 * We look up the provider in the static table typically provided by
1443 * board setup code. We first try to lookup the consumer device by
1444 * name. If the consumer device was passed in as NULL or if no match
1445 * was found, we try to find the consumer by directly looking it up
1446 * by name.
1447 *
1448 * If a match is found, the provider PWM chip is looked up by name
1449 * and a PWM device is requested using the PWM device per-chip index.
1450 *
1451 * The lookup algorithm was shamelessly taken from the clock
1452 * framework:
1453 *
1454 * We do slightly fuzzy matching here:
1455 * An entry with a NULL ID is assumed to be a wildcard.
1456 * If an entry has a device ID, it must match
1457 * If an entry has a connection ID, it must match
1458 * Then we take the most specific entry - with the following order
1459 * of precedence: dev+con > dev only > con only.
1460 */
1461 scoped_guard(mutex, &pwm_lookup_lock)
1462 list_for_each_entry(p, &pwm_lookup_list, list) {
1463 match = 0;
1464
1465 if (p->dev_id) {
1466 if (!dev_id || strcmp(p->dev_id, dev_id))
1467 continue;
1468
1469 match += 2;
1470 }
1471
1472 if (p->con_id) {
1473 if (!con_id || strcmp(p->con_id, con_id))
1474 continue;
1475
1476 match += 1;
1477 }
1478
1479 if (match > best) {
1480 chosen = p;
1481
1482 if (match != 3)
1483 best = match;
1484 else
1485 break;
1486 }
1487 }
1488
1489 if (!chosen)
1490 return ERR_PTR(-ENODEV);
1491
1492 chip = pwmchip_find_by_name(chosen->provider);
1493
1494 /*
1495 * If the lookup entry specifies a module, load the module and retry
1496 * the PWM chip lookup. This can be used to work around driver load
1497 * ordering issues if driver's can't be made to properly support the
1498 * deferred probe mechanism.
1499 */
1500 if (!chip && chosen->module) {
1501 err = request_module(chosen->module);
1502 if (err == 0)
1503 chip = pwmchip_find_by_name(chosen->provider);
1504 }
1505
1506 if (!chip)
1507 return ERR_PTR(-EPROBE_DEFER);
1508
1509 pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
1510 if (IS_ERR(pwm))
1511 return pwm;
1512
1513 dl = pwm_device_link_add(dev, pwm);
1514 if (IS_ERR(dl)) {
1515 pwm_put(pwm);
1516 return ERR_CAST(dl);
1517 }
1518
1519 pwm->args.period = chosen->period;
1520 pwm->args.polarity = chosen->polarity;
1521
1522 return pwm;
1523 }
1524 EXPORT_SYMBOL_GPL(pwm_get);
1525
1526 /**
1527 * pwm_put() - release a PWM device
1528 * @pwm: PWM device
1529 */
pwm_put(struct pwm_device * pwm)1530 void pwm_put(struct pwm_device *pwm)
1531 {
1532 struct pwm_chip *chip;
1533
1534 if (!pwm)
1535 return;
1536
1537 chip = pwm->chip;
1538
1539 guard(mutex)(&pwm_lock);
1540
1541 if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
1542 pr_warn("PWM device already freed\n");
1543 return;
1544 }
1545
1546 if (chip->ops->free)
1547 pwm->chip->ops->free(pwm->chip, pwm);
1548
1549 pwm->label = NULL;
1550
1551 put_device(&chip->dev);
1552
1553 module_put(chip->owner);
1554 }
1555 EXPORT_SYMBOL_GPL(pwm_put);
1556
devm_pwm_release(void * pwm)1557 static void devm_pwm_release(void *pwm)
1558 {
1559 pwm_put(pwm);
1560 }
1561
1562 /**
1563 * devm_pwm_get() - resource managed pwm_get()
1564 * @dev: device for PWM consumer
1565 * @con_id: consumer name
1566 *
1567 * This function performs like pwm_get() but the acquired PWM device will
1568 * automatically be released on driver detach.
1569 *
1570 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1571 * error code on failure.
1572 */
devm_pwm_get(struct device * dev,const char * con_id)1573 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
1574 {
1575 struct pwm_device *pwm;
1576 int ret;
1577
1578 pwm = pwm_get(dev, con_id);
1579 if (IS_ERR(pwm))
1580 return pwm;
1581
1582 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1583 if (ret)
1584 return ERR_PTR(ret);
1585
1586 return pwm;
1587 }
1588 EXPORT_SYMBOL_GPL(devm_pwm_get);
1589
1590 /**
1591 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
1592 * @dev: device for PWM consumer
1593 * @fwnode: firmware node to get the PWM from
1594 * @con_id: consumer name
1595 *
1596 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
1597 * acpi_pwm_get() for a detailed description.
1598 *
1599 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
1600 * error code on failure.
1601 */
devm_fwnode_pwm_get(struct device * dev,struct fwnode_handle * fwnode,const char * con_id)1602 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
1603 struct fwnode_handle *fwnode,
1604 const char *con_id)
1605 {
1606 struct pwm_device *pwm = ERR_PTR(-ENODEV);
1607 int ret;
1608
1609 if (is_of_node(fwnode))
1610 pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
1611 else if (is_acpi_node(fwnode))
1612 pwm = acpi_pwm_get(fwnode);
1613 if (IS_ERR(pwm))
1614 return pwm;
1615
1616 ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
1617 if (ret)
1618 return ERR_PTR(ret);
1619
1620 return pwm;
1621 }
1622 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
1623
pwm_dbg_show(struct pwm_chip * chip,struct seq_file * s)1624 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
1625 {
1626 unsigned int i;
1627
1628 for (i = 0; i < chip->npwm; i++) {
1629 struct pwm_device *pwm = &chip->pwms[i];
1630 struct pwm_state state;
1631
1632 pwm_get_state(pwm, &state);
1633
1634 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
1635
1636 if (test_bit(PWMF_REQUESTED, &pwm->flags))
1637 seq_puts(s, " requested");
1638
1639 if (state.enabled)
1640 seq_puts(s, " enabled");
1641
1642 seq_printf(s, " period: %llu ns", state.period);
1643 seq_printf(s, " duty: %llu ns", state.duty_cycle);
1644 seq_printf(s, " polarity: %s",
1645 state.polarity ? "inverse" : "normal");
1646
1647 if (state.usage_power)
1648 seq_puts(s, " usage_power");
1649
1650 seq_puts(s, "\n");
1651 }
1652 }
1653
pwm_seq_start(struct seq_file * s,loff_t * pos)1654 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
1655 {
1656 unsigned long id = *pos;
1657 void *ret;
1658
1659 mutex_lock(&pwm_lock);
1660 s->private = "";
1661
1662 ret = idr_get_next_ul(&pwm_chips, &id);
1663 *pos = id;
1664 return ret;
1665 }
1666
pwm_seq_next(struct seq_file * s,void * v,loff_t * pos)1667 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
1668 {
1669 unsigned long id = *pos + 1;
1670 void *ret;
1671
1672 s->private = "\n";
1673
1674 ret = idr_get_next_ul(&pwm_chips, &id);
1675 *pos = id;
1676 return ret;
1677 }
1678
pwm_seq_stop(struct seq_file * s,void * v)1679 static void pwm_seq_stop(struct seq_file *s, void *v)
1680 {
1681 mutex_unlock(&pwm_lock);
1682 }
1683
pwm_seq_show(struct seq_file * s,void * v)1684 static int pwm_seq_show(struct seq_file *s, void *v)
1685 {
1686 struct pwm_chip *chip = v;
1687
1688 seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n",
1689 (char *)s->private, chip->id,
1690 pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus",
1691 dev_name(pwmchip_parent(chip)), chip->npwm,
1692 (chip->npwm != 1) ? "s" : "");
1693
1694 pwm_dbg_show(chip, s);
1695
1696 return 0;
1697 }
1698
1699 static const struct seq_operations pwm_debugfs_sops = {
1700 .start = pwm_seq_start,
1701 .next = pwm_seq_next,
1702 .stop = pwm_seq_stop,
1703 .show = pwm_seq_show,
1704 };
1705
1706 DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
1707
pwm_init(void)1708 static int __init pwm_init(void)
1709 {
1710 int ret;
1711
1712 ret = class_register(&pwm_class);
1713 if (ret) {
1714 pr_err("Failed to initialize PWM class (%pe)\n", ERR_PTR(ret));
1715 return ret;
1716 }
1717
1718 if (IS_ENABLED(CONFIG_DEBUG_FS))
1719 debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
1720
1721 return 0;
1722 }
1723 subsys_initcall(pwm_init);
1724