xref: /linux/drivers/pwm/core.c (revision 3a39d672e7f48b8d6b91a09afa4b55352773b4b5)
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