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1 /*
2  * Generic pwmlib implementation
3  *
4  * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
5  * Copyright (C) 2011-2012 Avionic Design GmbH
6  *
7  *  This program is free software; you can redistribute it and/or modify
8  *  it under the terms of the GNU General Public License as published by
9  *  the Free Software Foundation; either version 2, or (at your option)
10  *  any later version.
11  *
12  *  This program is distributed in the hope that it will be useful,
13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *  GNU General Public License for more details.
16  *
17  *  You should have received a copy of the GNU General Public License
18  *  along with this program; see the file COPYING.  If not, write to
19  *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
20  */
21 
22 #include <linux/module.h>
23 #include <linux/pwm.h>
24 #include <linux/radix-tree.h>
25 #include <linux/list.h>
26 #include <linux/mutex.h>
27 #include <linux/err.h>
28 #include <linux/slab.h>
29 #include <linux/device.h>
30 #include <linux/debugfs.h>
31 #include <linux/seq_file.h>
32 
33 #include <dt-bindings/pwm/pwm.h>
34 
35 #define MAX_PWMS 1024
36 
37 static DEFINE_MUTEX(pwm_lookup_lock);
38 static LIST_HEAD(pwm_lookup_list);
39 static DEFINE_MUTEX(pwm_lock);
40 static LIST_HEAD(pwm_chips);
41 static DECLARE_BITMAP(allocated_pwms, MAX_PWMS);
42 static RADIX_TREE(pwm_tree, GFP_KERNEL);
43 
pwm_to_device(unsigned int pwm)44 static struct pwm_device *pwm_to_device(unsigned int pwm)
45 {
46 	return radix_tree_lookup(&pwm_tree, pwm);
47 }
48 
alloc_pwms(int pwm,unsigned int count)49 static int alloc_pwms(int pwm, unsigned int count)
50 {
51 	unsigned int from = 0;
52 	unsigned int start;
53 
54 	if (pwm >= MAX_PWMS)
55 		return -EINVAL;
56 
57 	if (pwm >= 0)
58 		from = pwm;
59 
60 	start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
61 					   count, 0);
62 
63 	if (pwm >= 0 && start != pwm)
64 		return -EEXIST;
65 
66 	if (start + count > MAX_PWMS)
67 		return -ENOSPC;
68 
69 	return start;
70 }
71 
free_pwms(struct pwm_chip * chip)72 static void free_pwms(struct pwm_chip *chip)
73 {
74 	unsigned int i;
75 
76 	for (i = 0; i < chip->npwm; i++) {
77 		struct pwm_device *pwm = &chip->pwms[i];
78 		radix_tree_delete(&pwm_tree, pwm->pwm);
79 	}
80 
81 	bitmap_clear(allocated_pwms, chip->base, chip->npwm);
82 
83 	kfree(chip->pwms);
84 	chip->pwms = NULL;
85 }
86 
pwmchip_find_by_name(const char * name)87 static struct pwm_chip *pwmchip_find_by_name(const char *name)
88 {
89 	struct pwm_chip *chip;
90 
91 	if (!name)
92 		return NULL;
93 
94 	mutex_lock(&pwm_lock);
95 
96 	list_for_each_entry(chip, &pwm_chips, list) {
97 		const char *chip_name = dev_name(chip->dev);
98 
99 		if (chip_name && strcmp(chip_name, name) == 0) {
100 			mutex_unlock(&pwm_lock);
101 			return chip;
102 		}
103 	}
104 
105 	mutex_unlock(&pwm_lock);
106 
107 	return NULL;
108 }
109 
pwm_device_request(struct pwm_device * pwm,const char * label)110 static int pwm_device_request(struct pwm_device *pwm, const char *label)
111 {
112 	int err;
113 
114 	if (test_bit(PWMF_REQUESTED, &pwm->flags))
115 		return -EBUSY;
116 
117 	if (!try_module_get(pwm->chip->ops->owner))
118 		return -ENODEV;
119 
120 	if (pwm->chip->ops->request) {
121 		err = pwm->chip->ops->request(pwm->chip, pwm);
122 		if (err) {
123 			module_put(pwm->chip->ops->owner);
124 			return err;
125 		}
126 	}
127 
128 	set_bit(PWMF_REQUESTED, &pwm->flags);
129 	pwm->label = label;
130 
131 	return 0;
132 }
133 
134 struct pwm_device *
of_pwm_xlate_with_flags(struct pwm_chip * pc,const struct of_phandle_args * args)135 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
136 {
137 	struct pwm_device *pwm;
138 
139 	if (pc->of_pwm_n_cells < 3)
140 		return ERR_PTR(-EINVAL);
141 
142 	if (args->args[0] >= pc->npwm)
143 		return ERR_PTR(-EINVAL);
144 
145 	pwm = pwm_request_from_chip(pc, args->args[0], NULL);
146 	if (IS_ERR(pwm))
147 		return pwm;
148 
149 	pwm_set_period(pwm, args->args[1]);
150 
151 	if (args->args[2] & PWM_POLARITY_INVERTED)
152 		pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
153 	else
154 		pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
155 
156 	return pwm;
157 }
158 EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);
159 
160 static struct pwm_device *
of_pwm_simple_xlate(struct pwm_chip * pc,const struct of_phandle_args * args)161 of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
162 {
163 	struct pwm_device *pwm;
164 
165 	if (pc->of_pwm_n_cells < 2)
166 		return ERR_PTR(-EINVAL);
167 
168 	if (args->args[0] >= pc->npwm)
169 		return ERR_PTR(-EINVAL);
170 
171 	pwm = pwm_request_from_chip(pc, args->args[0], NULL);
172 	if (IS_ERR(pwm))
173 		return pwm;
174 
175 	pwm_set_period(pwm, args->args[1]);
176 
177 	return pwm;
178 }
179 
of_pwmchip_add(struct pwm_chip * chip)180 static void of_pwmchip_add(struct pwm_chip *chip)
181 {
182 	if (!chip->dev || !chip->dev->of_node)
183 		return;
184 
185 	if (!chip->of_xlate) {
186 		chip->of_xlate = of_pwm_simple_xlate;
187 		chip->of_pwm_n_cells = 2;
188 	}
189 
190 	of_node_get(chip->dev->of_node);
191 }
192 
of_pwmchip_remove(struct pwm_chip * chip)193 static void of_pwmchip_remove(struct pwm_chip *chip)
194 {
195 	if (chip->dev && chip->dev->of_node)
196 		of_node_put(chip->dev->of_node);
197 }
198 
199 /**
200  * pwm_set_chip_data() - set private chip data for a PWM
201  * @pwm: PWM device
202  * @data: pointer to chip-specific data
203  */
pwm_set_chip_data(struct pwm_device * pwm,void * data)204 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
205 {
206 	if (!pwm)
207 		return -EINVAL;
208 
209 	pwm->chip_data = data;
210 
211 	return 0;
212 }
213 EXPORT_SYMBOL_GPL(pwm_set_chip_data);
214 
215 /**
216  * pwm_get_chip_data() - get private chip data for a PWM
217  * @pwm: PWM device
218  */
pwm_get_chip_data(struct pwm_device * pwm)219 void *pwm_get_chip_data(struct pwm_device *pwm)
220 {
221 	return pwm ? pwm->chip_data : NULL;
222 }
223 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
224 
225 /**
226  * pwmchip_add() - register a new PWM chip
227  * @chip: the PWM chip to add
228  *
229  * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
230  * will be used.
231  */
pwmchip_add(struct pwm_chip * chip)232 int pwmchip_add(struct pwm_chip *chip)
233 {
234 	struct pwm_device *pwm;
235 	unsigned int i;
236 	int ret;
237 
238 	if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
239 	    !chip->ops->enable || !chip->ops->disable || !chip->npwm)
240 		return -EINVAL;
241 
242 	mutex_lock(&pwm_lock);
243 
244 	ret = alloc_pwms(chip->base, chip->npwm);
245 	if (ret < 0)
246 		goto out;
247 
248 	chip->pwms = kzalloc(chip->npwm * sizeof(*pwm), GFP_KERNEL);
249 	if (!chip->pwms) {
250 		ret = -ENOMEM;
251 		goto out;
252 	}
253 
254 	chip->base = ret;
255 
256 	for (i = 0; i < chip->npwm; i++) {
257 		pwm = &chip->pwms[i];
258 
259 		pwm->chip = chip;
260 		pwm->pwm = chip->base + i;
261 		pwm->hwpwm = i;
262 
263 		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
264 	}
265 
266 	bitmap_set(allocated_pwms, chip->base, chip->npwm);
267 
268 	INIT_LIST_HEAD(&chip->list);
269 	list_add(&chip->list, &pwm_chips);
270 
271 	ret = 0;
272 
273 	if (IS_ENABLED(CONFIG_OF))
274 		of_pwmchip_add(chip);
275 
276 	pwmchip_sysfs_export(chip);
277 
278 out:
279 	mutex_unlock(&pwm_lock);
280 	return ret;
281 }
282 EXPORT_SYMBOL_GPL(pwmchip_add);
283 
284 /**
285  * pwmchip_remove() - remove a PWM chip
286  * @chip: the PWM chip to remove
287  *
288  * Removes a PWM chip. This function may return busy if the PWM chip provides
289  * a PWM device that is still requested.
290  */
pwmchip_remove(struct pwm_chip * chip)291 int pwmchip_remove(struct pwm_chip *chip)
292 {
293 	unsigned int i;
294 	int ret = 0;
295 
296 	pwmchip_sysfs_unexport_children(chip);
297 
298 	mutex_lock(&pwm_lock);
299 
300 	for (i = 0; i < chip->npwm; i++) {
301 		struct pwm_device *pwm = &chip->pwms[i];
302 
303 		if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
304 			ret = -EBUSY;
305 			goto out;
306 		}
307 	}
308 
309 	list_del_init(&chip->list);
310 
311 	if (IS_ENABLED(CONFIG_OF))
312 		of_pwmchip_remove(chip);
313 
314 	free_pwms(chip);
315 
316 	pwmchip_sysfs_unexport(chip);
317 
318 out:
319 	mutex_unlock(&pwm_lock);
320 	return ret;
321 }
322 EXPORT_SYMBOL_GPL(pwmchip_remove);
323 
324 /**
325  * pwm_request() - request a PWM device
326  * @pwm_id: global PWM device index
327  * @label: PWM device label
328  *
329  * This function is deprecated, use pwm_get() instead.
330  */
pwm_request(int pwm,const char * label)331 struct pwm_device *pwm_request(int pwm, const char *label)
332 {
333 	struct pwm_device *dev;
334 	int err;
335 
336 	if (pwm < 0 || pwm >= MAX_PWMS)
337 		return ERR_PTR(-EINVAL);
338 
339 	mutex_lock(&pwm_lock);
340 
341 	dev = pwm_to_device(pwm);
342 	if (!dev) {
343 		dev = ERR_PTR(-EPROBE_DEFER);
344 		goto out;
345 	}
346 
347 	err = pwm_device_request(dev, label);
348 	if (err < 0)
349 		dev = ERR_PTR(err);
350 
351 out:
352 	mutex_unlock(&pwm_lock);
353 
354 	return dev;
355 }
356 EXPORT_SYMBOL_GPL(pwm_request);
357 
358 /**
359  * pwm_request_from_chip() - request a PWM device relative to a PWM chip
360  * @chip: PWM chip
361  * @index: per-chip index of the PWM to request
362  * @label: a literal description string of this PWM
363  *
364  * Returns the PWM at the given index of the given PWM chip. A negative error
365  * code is returned if the index is not valid for the specified PWM chip or
366  * if the PWM device cannot be requested.
367  */
pwm_request_from_chip(struct pwm_chip * chip,unsigned int index,const char * label)368 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
369 					 unsigned int index,
370 					 const char *label)
371 {
372 	struct pwm_device *pwm;
373 	int err;
374 
375 	if (!chip || index >= chip->npwm)
376 		return ERR_PTR(-EINVAL);
377 
378 	mutex_lock(&pwm_lock);
379 	pwm = &chip->pwms[index];
380 
381 	err = pwm_device_request(pwm, label);
382 	if (err < 0)
383 		pwm = ERR_PTR(err);
384 
385 	mutex_unlock(&pwm_lock);
386 	return pwm;
387 }
388 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
389 
390 /**
391  * pwm_free() - free a PWM device
392  * @pwm: PWM device
393  *
394  * This function is deprecated, use pwm_put() instead.
395  */
pwm_free(struct pwm_device * pwm)396 void pwm_free(struct pwm_device *pwm)
397 {
398 	pwm_put(pwm);
399 }
400 EXPORT_SYMBOL_GPL(pwm_free);
401 
402 /**
403  * pwm_config() - change a PWM device configuration
404  * @pwm: PWM device
405  * @duty_ns: "on" time (in nanoseconds)
406  * @period_ns: duration (in nanoseconds) of one cycle
407  */
pwm_config(struct pwm_device * pwm,int duty_ns,int period_ns)408 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
409 {
410 	int err;
411 
412 	if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
413 		return -EINVAL;
414 
415 	err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
416 	if (err)
417 		return err;
418 
419 	pwm->duty_cycle = duty_ns;
420 	pwm->period = period_ns;
421 
422 	return 0;
423 }
424 EXPORT_SYMBOL_GPL(pwm_config);
425 
426 /**
427  * pwm_set_polarity() - configure the polarity of a PWM signal
428  * @pwm: PWM device
429  * @polarity: new polarity of the PWM signal
430  *
431  * Note that the polarity cannot be configured while the PWM device is enabled
432  */
pwm_set_polarity(struct pwm_device * pwm,enum pwm_polarity polarity)433 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
434 {
435 	int err;
436 
437 	if (!pwm || !pwm->chip->ops)
438 		return -EINVAL;
439 
440 	if (!pwm->chip->ops->set_polarity)
441 		return -ENOSYS;
442 
443 	if (test_bit(PWMF_ENABLED, &pwm->flags))
444 		return -EBUSY;
445 
446 	err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
447 	if (err)
448 		return err;
449 
450 	pwm->polarity = polarity;
451 
452 	return 0;
453 }
454 EXPORT_SYMBOL_GPL(pwm_set_polarity);
455 
456 /**
457  * pwm_enable() - start a PWM output toggling
458  * @pwm: PWM device
459  */
pwm_enable(struct pwm_device * pwm)460 int pwm_enable(struct pwm_device *pwm)
461 {
462 	if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
463 		return pwm->chip->ops->enable(pwm->chip, pwm);
464 
465 	return pwm ? 0 : -EINVAL;
466 }
467 EXPORT_SYMBOL_GPL(pwm_enable);
468 
469 /**
470  * pwm_disable() - stop a PWM output toggling
471  * @pwm: PWM device
472  */
pwm_disable(struct pwm_device * pwm)473 void pwm_disable(struct pwm_device *pwm)
474 {
475 	if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
476 		pwm->chip->ops->disable(pwm->chip, pwm);
477 }
478 EXPORT_SYMBOL_GPL(pwm_disable);
479 
of_node_to_pwmchip(struct device_node * np)480 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
481 {
482 	struct pwm_chip *chip;
483 
484 	mutex_lock(&pwm_lock);
485 
486 	list_for_each_entry(chip, &pwm_chips, list)
487 		if (chip->dev && chip->dev->of_node == np) {
488 			mutex_unlock(&pwm_lock);
489 			return chip;
490 		}
491 
492 	mutex_unlock(&pwm_lock);
493 
494 	return ERR_PTR(-EPROBE_DEFER);
495 }
496 
497 /**
498  * of_pwm_get() - request a PWM via the PWM framework
499  * @np: device node to get the PWM from
500  * @con_id: consumer name
501  *
502  * Returns the PWM device parsed from the phandle and index specified in the
503  * "pwms" property of a device tree node or a negative error-code on failure.
504  * Values parsed from the device tree are stored in the returned PWM device
505  * object.
506  *
507  * If con_id is NULL, the first PWM device listed in the "pwms" property will
508  * be requested. Otherwise the "pwm-names" property is used to do a reverse
509  * lookup of the PWM index. This also means that the "pwm-names" property
510  * becomes mandatory for devices that look up the PWM device via the con_id
511  * parameter.
512  */
of_pwm_get(struct device_node * np,const char * con_id)513 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
514 {
515 	struct pwm_device *pwm = NULL;
516 	struct of_phandle_args args;
517 	struct pwm_chip *pc;
518 	int index = 0;
519 	int err;
520 
521 	if (con_id) {
522 		index = of_property_match_string(np, "pwm-names", con_id);
523 		if (index < 0)
524 			return ERR_PTR(index);
525 	}
526 
527 	err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
528 					 &args);
529 	if (err) {
530 		pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
531 		return ERR_PTR(err);
532 	}
533 
534 	pc = of_node_to_pwmchip(args.np);
535 	if (IS_ERR(pc)) {
536 		pr_debug("%s(): PWM chip not found\n", __func__);
537 		pwm = ERR_CAST(pc);
538 		goto put;
539 	}
540 
541 	if (args.args_count != pc->of_pwm_n_cells) {
542 		pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
543 			 args.np->full_name);
544 		pwm = ERR_PTR(-EINVAL);
545 		goto put;
546 	}
547 
548 	pwm = pc->of_xlate(pc, &args);
549 	if (IS_ERR(pwm))
550 		goto put;
551 
552 	/*
553 	 * If a consumer name was not given, try to look it up from the
554 	 * "pwm-names" property if it exists. Otherwise use the name of
555 	 * the user device node.
556 	 */
557 	if (!con_id) {
558 		err = of_property_read_string_index(np, "pwm-names", index,
559 						    &con_id);
560 		if (err < 0)
561 			con_id = np->name;
562 	}
563 
564 	pwm->label = con_id;
565 
566 put:
567 	of_node_put(args.np);
568 
569 	return pwm;
570 }
571 EXPORT_SYMBOL_GPL(of_pwm_get);
572 
573 /**
574  * pwm_add_table() - register PWM device consumers
575  * @table: array of consumers to register
576  * @num: number of consumers in table
577  */
pwm_add_table(struct pwm_lookup * table,size_t num)578 void __init pwm_add_table(struct pwm_lookup *table, size_t num)
579 {
580 	mutex_lock(&pwm_lookup_lock);
581 
582 	while (num--) {
583 		list_add_tail(&table->list, &pwm_lookup_list);
584 		table++;
585 	}
586 
587 	mutex_unlock(&pwm_lookup_lock);
588 }
589 
590 /**
591  * pwm_get() - look up and request a PWM device
592  * @dev: device for PWM consumer
593  * @con_id: consumer name
594  *
595  * Lookup is first attempted using DT. If the device was not instantiated from
596  * a device tree, a PWM chip and a relative index is looked up via a table
597  * supplied by board setup code (see pwm_add_table()).
598  *
599  * Once a PWM chip has been found the specified PWM device will be requested
600  * and is ready to be used.
601  */
pwm_get(struct device * dev,const char * con_id)602 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
603 {
604 	struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
605 	const char *dev_id = dev ? dev_name(dev) : NULL;
606 	struct pwm_chip *chip = NULL;
607 	unsigned int best = 0;
608 	struct pwm_lookup *p, *chosen = NULL;
609 	unsigned int match;
610 
611 	/* look up via DT first */
612 	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
613 		return of_pwm_get(dev->of_node, con_id);
614 
615 	/*
616 	 * We look up the provider in the static table typically provided by
617 	 * board setup code. We first try to lookup the consumer device by
618 	 * name. If the consumer device was passed in as NULL or if no match
619 	 * was found, we try to find the consumer by directly looking it up
620 	 * by name.
621 	 *
622 	 * If a match is found, the provider PWM chip is looked up by name
623 	 * and a PWM device is requested using the PWM device per-chip index.
624 	 *
625 	 * The lookup algorithm was shamelessly taken from the clock
626 	 * framework:
627 	 *
628 	 * We do slightly fuzzy matching here:
629 	 *  An entry with a NULL ID is assumed to be a wildcard.
630 	 *  If an entry has a device ID, it must match
631 	 *  If an entry has a connection ID, it must match
632 	 * Then we take the most specific entry - with the following order
633 	 * of precedence: dev+con > dev only > con only.
634 	 */
635 	mutex_lock(&pwm_lookup_lock);
636 
637 	list_for_each_entry(p, &pwm_lookup_list, list) {
638 		match = 0;
639 
640 		if (p->dev_id) {
641 			if (!dev_id || strcmp(p->dev_id, dev_id))
642 				continue;
643 
644 			match += 2;
645 		}
646 
647 		if (p->con_id) {
648 			if (!con_id || strcmp(p->con_id, con_id))
649 				continue;
650 
651 			match += 1;
652 		}
653 
654 		if (match > best) {
655 			chosen = p;
656 
657 			if (match != 3)
658 				best = match;
659 			else
660 				break;
661 		}
662 	}
663 
664 	if (!chosen)
665 		goto out;
666 
667 	chip = pwmchip_find_by_name(chosen->provider);
668 	if (!chip)
669 		goto out;
670 
671 	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
672 	if (IS_ERR(pwm))
673 		goto out;
674 
675 	pwm_set_period(pwm, chosen->period);
676 	pwm_set_polarity(pwm, chosen->polarity);
677 
678 out:
679 	mutex_unlock(&pwm_lookup_lock);
680 	return pwm;
681 }
682 EXPORT_SYMBOL_GPL(pwm_get);
683 
684 /**
685  * pwm_put() - release a PWM device
686  * @pwm: PWM device
687  */
pwm_put(struct pwm_device * pwm)688 void pwm_put(struct pwm_device *pwm)
689 {
690 	if (!pwm)
691 		return;
692 
693 	mutex_lock(&pwm_lock);
694 
695 	if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
696 		pr_warn("PWM device already freed\n");
697 		goto out;
698 	}
699 
700 	if (pwm->chip->ops->free)
701 		pwm->chip->ops->free(pwm->chip, pwm);
702 
703 	pwm->label = NULL;
704 
705 	module_put(pwm->chip->ops->owner);
706 out:
707 	mutex_unlock(&pwm_lock);
708 }
709 EXPORT_SYMBOL_GPL(pwm_put);
710 
devm_pwm_release(struct device * dev,void * res)711 static void devm_pwm_release(struct device *dev, void *res)
712 {
713 	pwm_put(*(struct pwm_device **)res);
714 }
715 
716 /**
717  * devm_pwm_get() - resource managed pwm_get()
718  * @dev: device for PWM consumer
719  * @con_id: consumer name
720  *
721  * This function performs like pwm_get() but the acquired PWM device will
722  * automatically be released on driver detach.
723  */
devm_pwm_get(struct device * dev,const char * con_id)724 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
725 {
726 	struct pwm_device **ptr, *pwm;
727 
728 	ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
729 	if (!ptr)
730 		return ERR_PTR(-ENOMEM);
731 
732 	pwm = pwm_get(dev, con_id);
733 	if (!IS_ERR(pwm)) {
734 		*ptr = pwm;
735 		devres_add(dev, ptr);
736 	} else {
737 		devres_free(ptr);
738 	}
739 
740 	return pwm;
741 }
742 EXPORT_SYMBOL_GPL(devm_pwm_get);
743 
744 /**
745  * devm_of_pwm_get() - resource managed of_pwm_get()
746  * @dev: device for PWM consumer
747  * @np: device node to get the PWM from
748  * @con_id: consumer name
749  *
750  * This function performs like of_pwm_get() but the acquired PWM device will
751  * automatically be released on driver detach.
752  */
devm_of_pwm_get(struct device * dev,struct device_node * np,const char * con_id)753 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
754 				   const char *con_id)
755 {
756 	struct pwm_device **ptr, *pwm;
757 
758 	ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL);
759 	if (!ptr)
760 		return ERR_PTR(-ENOMEM);
761 
762 	pwm = of_pwm_get(np, con_id);
763 	if (!IS_ERR(pwm)) {
764 		*ptr = pwm;
765 		devres_add(dev, ptr);
766 	} else {
767 		devres_free(ptr);
768 	}
769 
770 	return pwm;
771 }
772 EXPORT_SYMBOL_GPL(devm_of_pwm_get);
773 
devm_pwm_match(struct device * dev,void * res,void * data)774 static int devm_pwm_match(struct device *dev, void *res, void *data)
775 {
776 	struct pwm_device **p = res;
777 
778 	if (WARN_ON(!p || !*p))
779 		return 0;
780 
781 	return *p == data;
782 }
783 
784 /**
785  * devm_pwm_put() - resource managed pwm_put()
786  * @dev: device for PWM consumer
787  * @pwm: PWM device
788  *
789  * Release a PWM previously allocated using devm_pwm_get(). Calling this
790  * function is usually not needed because devm-allocated resources are
791  * automatically released on driver detach.
792  */
devm_pwm_put(struct device * dev,struct pwm_device * pwm)793 void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
794 {
795 	WARN_ON(devres_release(dev, devm_pwm_release, devm_pwm_match, pwm));
796 }
797 EXPORT_SYMBOL_GPL(devm_pwm_put);
798 
799 /**
800   * pwm_can_sleep() - report whether PWM access will sleep
801   * @pwm: PWM device
802   *
803   * It returns true if accessing the PWM can sleep, false otherwise.
804   */
pwm_can_sleep(struct pwm_device * pwm)805 bool pwm_can_sleep(struct pwm_device *pwm)
806 {
807 	return pwm->chip->can_sleep;
808 }
809 EXPORT_SYMBOL_GPL(pwm_can_sleep);
810 
811 #ifdef CONFIG_DEBUG_FS
pwm_dbg_show(struct pwm_chip * chip,struct seq_file * s)812 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
813 {
814 	unsigned int i;
815 
816 	for (i = 0; i < chip->npwm; i++) {
817 		struct pwm_device *pwm = &chip->pwms[i];
818 
819 		seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
820 
821 		if (test_bit(PWMF_REQUESTED, &pwm->flags))
822 			seq_puts(s, " requested");
823 
824 		if (test_bit(PWMF_ENABLED, &pwm->flags))
825 			seq_puts(s, " enabled");
826 
827 		seq_puts(s, "\n");
828 	}
829 }
830 
pwm_seq_start(struct seq_file * s,loff_t * pos)831 static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
832 {
833 	mutex_lock(&pwm_lock);
834 	s->private = "";
835 
836 	return seq_list_start(&pwm_chips, *pos);
837 }
838 
pwm_seq_next(struct seq_file * s,void * v,loff_t * pos)839 static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
840 {
841 	s->private = "\n";
842 
843 	return seq_list_next(v, &pwm_chips, pos);
844 }
845 
pwm_seq_stop(struct seq_file * s,void * v)846 static void pwm_seq_stop(struct seq_file *s, void *v)
847 {
848 	mutex_unlock(&pwm_lock);
849 }
850 
pwm_seq_show(struct seq_file * s,void * v)851 static int pwm_seq_show(struct seq_file *s, void *v)
852 {
853 	struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
854 
855 	seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
856 		   chip->dev->bus ? chip->dev->bus->name : "no-bus",
857 		   dev_name(chip->dev), chip->npwm,
858 		   (chip->npwm != 1) ? "s" : "");
859 
860 	if (chip->ops->dbg_show)
861 		chip->ops->dbg_show(chip, s);
862 	else
863 		pwm_dbg_show(chip, s);
864 
865 	return 0;
866 }
867 
868 static const struct seq_operations pwm_seq_ops = {
869 	.start = pwm_seq_start,
870 	.next = pwm_seq_next,
871 	.stop = pwm_seq_stop,
872 	.show = pwm_seq_show,
873 };
874 
pwm_seq_open(struct inode * inode,struct file * file)875 static int pwm_seq_open(struct inode *inode, struct file *file)
876 {
877 	return seq_open(file, &pwm_seq_ops);
878 }
879 
880 static const struct file_operations pwm_debugfs_ops = {
881 	.owner = THIS_MODULE,
882 	.open = pwm_seq_open,
883 	.read = seq_read,
884 	.llseek = seq_lseek,
885 	.release = seq_release,
886 };
887 
pwm_debugfs_init(void)888 static int __init pwm_debugfs_init(void)
889 {
890 	debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
891 			    &pwm_debugfs_ops);
892 
893 	return 0;
894 }
895 
896 subsys_initcall(pwm_debugfs_init);
897 #endif /* CONFIG_DEBUG_FS */
898