summaryrefslogtreecommitdiffstats
path: root/drivers/leds/led-class.c
blob: 06b97fd49ad9a23ecf9b0bdfc9a18f8f237bc331 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
// SPDX-License-Identifier: GPL-2.0-only
/*
 * LED Class Core
 *
 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
 * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
 */

#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <uapi/linux/uleds.h>
#include <linux/of.h>
#include "leds.h"

static DEFINE_MUTEX(leds_lookup_lock);
static LIST_HEAD(leds_lookup_list);

static ssize_t brightness_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	/* no lock needed for this */
	led_update_brightness(led_cdev);

	return sprintf(buf, "%u\n", led_cdev->brightness);
}

static ssize_t brightness_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	unsigned long state;
	ssize_t ret;

	mutex_lock(&led_cdev->led_access);

	if (led_sysfs_is_disabled(led_cdev)) {
		ret = -EBUSY;
		goto unlock;
	}

	ret = kstrtoul(buf, 10, &state);
	if (ret)
		goto unlock;

	if (state == LED_OFF)
		led_trigger_remove(led_cdev);
	led_set_brightness(led_cdev, state);
	flush_work(&led_cdev->set_brightness_work);

	ret = size;
unlock:
	mutex_unlock(&led_cdev->led_access);
	return ret;
}
static DEVICE_ATTR_RW(brightness);

static ssize_t max_brightness_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", led_cdev->max_brightness);
}
static DEVICE_ATTR_RO(max_brightness);

#ifdef CONFIG_LEDS_TRIGGERS
static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
static struct bin_attribute *led_trigger_bin_attrs[] = {
	&bin_attr_trigger,
	NULL,
};
static const struct attribute_group led_trigger_group = {
	.bin_attrs = led_trigger_bin_attrs,
};
#endif

static struct attribute *led_class_attrs[] = {
	&dev_attr_brightness.attr,
	&dev_attr_max_brightness.attr,
	NULL,
};

static const struct attribute_group led_group = {
	.attrs = led_class_attrs,
};

static const struct attribute_group *led_groups[] = {
	&led_group,
#ifdef CONFIG_LEDS_TRIGGERS
	&led_trigger_group,
#endif
	NULL,
};

#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
static ssize_t brightness_hw_changed_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	if (led_cdev->brightness_hw_changed == -1)
		return -ENODATA;

	return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
}

static DEVICE_ATTR_RO(brightness_hw_changed);

static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
{
	struct device *dev = led_cdev->dev;
	int ret;

	ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
	if (ret) {
		dev_err(dev, "Error creating brightness_hw_changed\n");
		return ret;
	}

	led_cdev->brightness_hw_changed_kn =
		sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
	if (!led_cdev->brightness_hw_changed_kn) {
		dev_err(dev, "Error getting brightness_hw_changed kn\n");
		device_remove_file(dev, &dev_attr_brightness_hw_changed);
		return -ENXIO;
	}

	return 0;
}

static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
{
	sysfs_put(led_cdev->brightness_hw_changed_kn);
	device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
}

void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int brightness)
{
	if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
		return;

	led_cdev->brightness_hw_changed = brightness;
	sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
}
EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
#else
static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
{
	return 0;
}
static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
{
}
#endif

/**
 * led_classdev_suspend - suspend an led_classdev.
 * @led_cdev: the led_classdev to suspend.
 */
void led_classdev_suspend(struct led_classdev *led_cdev)
{
	led_cdev->flags |= LED_SUSPENDED;
	led_set_brightness_nopm(led_cdev, 0);
	flush_work(&led_cdev->set_brightness_work);
}
EXPORT_SYMBOL_GPL(led_classdev_suspend);

/**
 * led_classdev_resume - resume an led_classdev.
 * @led_cdev: the led_classdev to resume.
 */
void led_classdev_resume(struct led_classdev *led_cdev)
{
	led_set_brightness_nopm(led_cdev, led_cdev->brightness);

	if (led_cdev->flash_resume)
		led_cdev->flash_resume(led_cdev);

	led_cdev->flags &= ~LED_SUSPENDED;
}
EXPORT_SYMBOL_GPL(led_classdev_resume);

#ifdef CONFIG_PM_SLEEP
static int led_suspend(struct device *dev)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
		led_classdev_suspend(led_cdev);

	return 0;
}

static int led_resume(struct device *dev)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);

	if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
		led_classdev_resume(led_cdev);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);

static struct led_classdev *led_module_get(struct device *led_dev)
{
	struct led_classdev *led_cdev;

	if (!led_dev)
		return ERR_PTR(-EPROBE_DEFER);

	led_cdev = dev_get_drvdata(led_dev);

	if (!try_module_get(led_cdev->dev->parent->driver->owner)) {
		put_device(led_cdev->dev);
		return ERR_PTR(-ENODEV);
	}

	return led_cdev;
}

static const struct class leds_class = {
	.name = "leds",
	.dev_groups = led_groups,
	.pm = &leds_class_dev_pm_ops,
};

/**
 * of_led_get() - request a LED device via the LED framework
 * @np: device node to get the LED device from
 * @index: the index of the LED
 *
 * Returns the LED device parsed from the phandle specified in the "leds"
 * property of a device tree node or a negative error-code on failure.
 */
struct led_classdev *of_led_get(struct device_node *np, int index)
{
	struct device *led_dev;
	struct device_node *led_node;

	led_node = of_parse_phandle(np, "leds", index);
	if (!led_node)
		return ERR_PTR(-ENOENT);

	led_dev = class_find_device_by_of_node(&leds_class, led_node);
	of_node_put(led_node);

	return led_module_get(led_dev);
}
EXPORT_SYMBOL_GPL(of_led_get);

/**
 * led_put() - release a LED device
 * @led_cdev: LED device
 */
void led_put(struct led_classdev *led_cdev)
{
	module_put(led_cdev->dev->parent->driver->owner);
	put_device(led_cdev->dev);
}
EXPORT_SYMBOL_GPL(led_put);

static void devm_led_release(struct device *dev, void *res)
{
	struct led_classdev **p = res;

	led_put(*p);
}

static struct led_classdev *__devm_led_get(struct device *dev, struct led_classdev *led)
{
	struct led_classdev **dr;

	dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), GFP_KERNEL);
	if (!dr) {
		led_put(led);
		return ERR_PTR(-ENOMEM);
	}

	*dr = led;
	devres_add(dev, dr);

	return led;
}

/**
 * devm_of_led_get - Resource-managed request of a LED device
 * @dev:	LED consumer
 * @index:	index of the LED to obtain in the consumer
 *
 * The device node of the device is parse to find the request LED device.
 * The LED device returned from this function is automatically released
 * on driver detach.
 *
 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 */
struct led_classdev *__must_check devm_of_led_get(struct device *dev,
						  int index)
{
	struct led_classdev *led;

	if (!dev)
		return ERR_PTR(-EINVAL);

	led = of_led_get(dev->of_node, index);
	if (IS_ERR(led))
		return led;

	return __devm_led_get(dev, led);
}
EXPORT_SYMBOL_GPL(devm_of_led_get);

/**
 * led_get() - request a LED device via the LED framework
 * @dev: device for which to get the LED device
 * @con_id: name of the LED from the device's point of view
 *
 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 */
struct led_classdev *led_get(struct device *dev, char *con_id)
{
	struct led_lookup_data *lookup;
	const char *provider = NULL;
	struct device *led_dev;

	mutex_lock(&leds_lookup_lock);
	list_for_each_entry(lookup, &leds_lookup_list, list) {
		if (!strcmp(lookup->dev_id, dev_name(dev)) &&
		    !strcmp(lookup->con_id, con_id)) {
			provider = kstrdup_const(lookup->provider, GFP_KERNEL);
			break;
		}
	}
	mutex_unlock(&leds_lookup_lock);

	if (!provider)
		return ERR_PTR(-ENOENT);

	led_dev = class_find_device_by_name(&leds_class, provider);
	kfree_const(provider);

	return led_module_get(led_dev);
}
EXPORT_SYMBOL_GPL(led_get);

/**
 * devm_led_get() - request a LED device via the LED framework
 * @dev: device for which to get the LED device
 * @con_id: name of the LED from the device's point of view
 *
 * The LED device returned from this function is automatically released
 * on driver detach.
 *
 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 */
struct led_classdev *devm_led_get(struct device *dev, char *con_id)
{
	struct led_classdev *led;

	led = led_get(dev, con_id);
	if (IS_ERR(led))
		return led;

	return __devm_led_get(dev, led);
}
EXPORT_SYMBOL_GPL(devm_led_get);

/**
 * led_add_lookup() - Add a LED lookup table entry
 * @led_lookup: the lookup table entry to add
 *
 * Add a LED lookup table entry. On systems without devicetree the lookup table
 * is used by led_get() to find LEDs.
 */
void led_add_lookup(struct led_lookup_data *led_lookup)
{
	mutex_lock(&leds_lookup_lock);
	list_add_tail(&led_lookup->list, &leds_lookup_list);
	mutex_unlock(&leds_lookup_lock);
}
EXPORT_SYMBOL_GPL(led_add_lookup);

/**
 * led_remove_lookup() - Remove a LED lookup table entry
 * @led_lookup: the lookup table entry to remove
 */
void led_remove_lookup(struct led_lookup_data *led_lookup)
{
	mutex_lock(&leds_lookup_lock);
	list_del(&led_lookup->list);
	mutex_unlock(&leds_lookup_lock);
}
EXPORT_SYMBOL_GPL(led_remove_lookup);

/**
 * devm_of_led_get_optional - Resource-managed request of an optional LED device
 * @dev:	LED consumer
 * @index:	index of the LED to obtain in the consumer
 *
 * The device node of the device is parsed to find the requested LED device.
 * The LED device returned from this function is automatically released
 * on driver detach.
 *
 * @return a pointer to a LED device, ERR_PTR(errno) on failure and NULL if the
 * led was not found.
 */
struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
							int index)
{
	struct led_classdev *led;

	led = devm_of_led_get(dev, index);
	if (IS_ERR(led) && PTR_ERR(led) == -ENOENT)
		return NULL;

	return led;
}
EXPORT_SYMBOL_GPL(devm_of_led_get_optional);

static int led_classdev_next_name(const char *init_name, char *name,
				  size_t len)
{
	unsigned int i = 0;
	int ret = 0;
	struct device *dev;

	strscpy(name, init_name, len);

	while ((ret < len) &&
	       (dev = class_find_device_by_name(&leds_class, name))) {
		put_device(dev);
		ret = snprintf(name, len, "%s_%u", init_name, ++i);
	}

	if (ret >= len)
		return -ENOMEM;

	return i;
}

/**
 * led_classdev_register_ext - register a new object of led_classdev class
 *			       with init data.
 *
 * @parent: parent of LED device
 * @led_cdev: the led_classdev structure for this device.
 * @init_data: LED class device initialization data
 */
int led_classdev_register_ext(struct device *parent,
			      struct led_classdev *led_cdev,
			      struct led_init_data *init_data)
{
	char composed_name[LED_MAX_NAME_SIZE];
	char final_name[LED_MAX_NAME_SIZE];
	const char *proposed_name = composed_name;
	int ret;

	if (init_data) {
		if (init_data->devname_mandatory && !init_data->devicename) {
			dev_err(parent, "Mandatory device name is missing");
			return -EINVAL;
		}
		ret = led_compose_name(parent, init_data, composed_name);
		if (ret < 0)
			return ret;

		if (init_data->fwnode) {
			fwnode_property_read_string(init_data->fwnode,
				"linux,default-trigger",
				&led_cdev->default_trigger);

			if (fwnode_property_present(init_data->fwnode,
						    "retain-state-shutdown"))
				led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;

			fwnode_property_read_u32(init_data->fwnode,
				"max-brightness",
				&led_cdev->max_brightness);

			if (fwnode_property_present(init_data->fwnode, "color"))
				fwnode_property_read_u32(init_data->fwnode, "color",
							 &led_cdev->color);
		}
	} else {
		proposed_name = led_cdev->name;
	}

	ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
	if (ret < 0)
		return ret;
	else if (ret && led_cdev->flags & LED_REJECT_NAME_CONFLICT)
		return -EEXIST;
	else if (ret)
		dev_warn(parent, "Led %s renamed to %s due to name collision\n",
			 proposed_name, final_name);

	if (led_cdev->color >= LED_COLOR_ID_MAX)
		dev_warn(parent, "LED %s color identifier out of range\n", final_name);

	mutex_init(&led_cdev->led_access);
	mutex_lock(&led_cdev->led_access);
	led_cdev->dev = device_create_with_groups(&leds_class, parent, 0,
						  led_cdev, led_cdev->groups, "%s", final_name);
	if (IS_ERR(led_cdev->dev)) {
		mutex_unlock(&led_cdev->led_access);
		return PTR_ERR(led_cdev->dev);
	}
	if (init_data && init_data->fwnode)
		device_set_node(led_cdev->dev, init_data->fwnode);

	if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
		ret = led_add_brightness_hw_changed(led_cdev);
		if (ret) {
			device_unregister(led_cdev->dev);
			led_cdev->dev = NULL;
			mutex_unlock(&led_cdev->led_access);
			return ret;
		}
	}

	led_cdev->work_flags = 0;
#ifdef CONFIG_LEDS_TRIGGERS
	init_rwsem(&led_cdev->trigger_lock);
#endif
#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
	led_cdev->brightness_hw_changed = -1;
#endif
	/* add to the list of leds */
	down_write(&leds_list_lock);
	list_add_tail(&led_cdev->node, &leds_list);
	up_write(&leds_list_lock);

	if (!led_cdev->max_brightness)
		led_cdev->max_brightness = LED_FULL;

	led_update_brightness(led_cdev);

	led_init_core(led_cdev);

#ifdef CONFIG_LEDS_TRIGGERS
	led_trigger_set_default(led_cdev);
#endif

	mutex_unlock(&led_cdev->led_access);

	dev_dbg(parent, "Registered led device: %s\n",
			led_cdev->name);

	return 0;
}
EXPORT_SYMBOL_GPL(led_classdev_register_ext);

/**
 * led_classdev_unregister - unregisters a object of led_properties class.
 * @led_cdev: the led device to unregister
 *
 * Unregisters a previously registered via led_classdev_register object.
 */
void led_classdev_unregister(struct led_classdev *led_cdev)
{
	if (IS_ERR_OR_NULL(led_cdev->dev))
		return;

#ifdef CONFIG_LEDS_TRIGGERS
	down_write(&led_cdev->trigger_lock);
	if (led_cdev->trigger)
		led_trigger_set(led_cdev, NULL);
	up_write(&led_cdev->trigger_lock);
#endif

	led_cdev->flags |= LED_UNREGISTERING;

	/* Stop blinking */
	led_stop_software_blink(led_cdev);

	if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
		led_set_brightness(led_cdev, LED_OFF);

	flush_work(&led_cdev->set_brightness_work);

	if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
		led_remove_brightness_hw_changed(led_cdev);

	device_unregister(led_cdev->dev);

	down_write(&leds_list_lock);
	list_del(&led_cdev->node);
	up_write(&leds_list_lock);

	mutex_destroy(&led_cdev->led_access);
}
EXPORT_SYMBOL_GPL(led_classdev_unregister);

static void devm_led_classdev_release(struct device *dev, void *res)
{
	led_classdev_unregister(*(struct led_classdev **)res);
}

/**
 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
 *
 * @parent: parent of LED device
 * @led_cdev: the led_classdev structure for this device.
 * @init_data: LED class device initialization data
 */
int devm_led_classdev_register_ext(struct device *parent,
				   struct led_classdev *led_cdev,
				   struct led_init_data *init_data)
{
	struct led_classdev **dr;
	int rc;

	dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
	if (!dr)
		return -ENOMEM;

	rc = led_classdev_register_ext(parent, led_cdev, init_data);
	if (rc) {
		devres_free(dr);
		return rc;
	}

	*dr = led_cdev;
	devres_add(parent, dr);

	return 0;
}
EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);

static int devm_led_classdev_match(struct device *dev, void *res, void *data)
{
	struct led_classdev **p = res;

	if (WARN_ON(!p || !*p))
		return 0;

	return *p == data;
}

/**
 * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 * @dev: The device to unregister.
 * @led_cdev: the led_classdev structure for this device.
 */
void devm_led_classdev_unregister(struct device *dev,
				  struct led_classdev *led_cdev)
{
	WARN_ON(devres_release(dev,
			       devm_led_classdev_release,
			       devm_led_classdev_match, led_cdev));
}
EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);

static int __init leds_init(void)
{
	return class_register(&leds_class);
}

static void __exit leds_exit(void)
{
	class_unregister(&leds_class);
}

subsys_initcall(leds_init);
module_exit(leds_exit);

MODULE_AUTHOR("John Lenz, Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Class Interface");