summaryrefslogtreecommitdiffstats
path: root/drivers/video/backlight/backlight.c
blob: 3fccb6d3c8c343ee1735811a0fc184270e869bbc (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
/*
 * Backlight Lowlevel Control Abstraction
 *
 * Copyright (C) 2003,2004 Hewlett-Packard Company
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/backlight.h>
#include <linux/notifier.h>
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/fb.h>
#include <linux/slab.h>

#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif

static const char *const backlight_types[] = {
	[BACKLIGHT_RAW] = "raw",
	[BACKLIGHT_PLATFORM] = "platform",
	[BACKLIGHT_FIRMWARE] = "firmware",
};

#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
			   defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
/* This callback gets called when something important happens inside a
 * framebuffer driver. We're looking if that important event is blanking,
 * and if it is, we're switching backlight power as well ...
 */
static int fb_notifier_callback(struct notifier_block *self,
				unsigned long event, void *data)
{
	struct backlight_device *bd;
	struct fb_event *evdata = data;

	/* If we aren't interested in this event, skip it immediately ... */
	if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
		return 0;

	bd = container_of(self, struct backlight_device, fb_notif);
	mutex_lock(&bd->ops_lock);
	if (bd->ops)
		if (!bd->ops->check_fb ||
		    bd->ops->check_fb(bd, evdata->info)) {
			bd->props.fb_blank = *(int *)evdata->data;
			if (bd->props.fb_blank == FB_BLANK_UNBLANK)
				bd->props.state &= ~BL_CORE_FBBLANK;
			else
				bd->props.state |= BL_CORE_FBBLANK;
			backlight_update_status(bd);
		}
	mutex_unlock(&bd->ops_lock);
	return 0;
}

static int backlight_register_fb(struct backlight_device *bd)
{
	memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
	bd->fb_notif.notifier_call = fb_notifier_callback;

	return fb_register_client(&bd->fb_notif);
}

static void backlight_unregister_fb(struct backlight_device *bd)
{
	fb_unregister_client(&bd->fb_notif);
}
#else
static inline int backlight_register_fb(struct backlight_device *bd)
{
	return 0;
}

static inline void backlight_unregister_fb(struct backlight_device *bd)
{
}
#endif /* CONFIG_FB */

static void backlight_generate_event(struct backlight_device *bd,
				     enum backlight_update_reason reason)
{
	char *envp[2];

	switch (reason) {
	case BACKLIGHT_UPDATE_SYSFS:
		envp[0] = "SOURCE=sysfs";
		break;
	case BACKLIGHT_UPDATE_HOTKEY:
		envp[0] = "SOURCE=hotkey";
		break;
	default:
		envp[0] = "SOURCE=unknown";
		break;
	}
	envp[1] = NULL;
	kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp);
	sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
}

static ssize_t backlight_show_power(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct backlight_device *bd = to_backlight_device(dev);

	return sprintf(buf, "%d\n", bd->props.power);
}

static ssize_t backlight_store_power(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	int rc;
	struct backlight_device *bd = to_backlight_device(dev);
	unsigned long power;

	rc = kstrtoul(buf, 0, &power);
	if (rc)
		return rc;

	rc = -ENXIO;
	mutex_lock(&bd->ops_lock);
	if (bd->ops) {
		pr_debug("set power to %lu\n", power);
		if (bd->props.power != power) {
			bd->props.power = power;
			backlight_update_status(bd);
		}
		rc = count;
	}
	mutex_unlock(&bd->ops_lock);

	return rc;
}

static ssize_t backlight_show_brightness(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct backlight_device *bd = to_backlight_device(dev);

	return sprintf(buf, "%d\n", bd->props.brightness);
}

static ssize_t backlight_store_brightness(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	int rc;
	struct backlight_device *bd = to_backlight_device(dev);
	unsigned long brightness;

	rc = kstrtoul(buf, 0, &brightness);
	if (rc)
		return rc;

	rc = -ENXIO;

	mutex_lock(&bd->ops_lock);
	if (bd->ops) {
		if (brightness > bd->props.max_brightness)
			rc = -EINVAL;
		else {
			pr_debug("set brightness to %lu\n", brightness);
			bd->props.brightness = brightness;
			backlight_update_status(bd);
			rc = count;
		}
	}
	mutex_unlock(&bd->ops_lock);

	backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS);

	return rc;
}

static ssize_t backlight_show_type(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct backlight_device *bd = to_backlight_device(dev);

	return sprintf(buf, "%s\n", backlight_types[bd->props.type]);
}

static ssize_t backlight_show_max_brightness(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct backlight_device *bd = to_backlight_device(dev);

	return sprintf(buf, "%d\n", bd->props.max_brightness);
}

static ssize_t backlight_show_actual_brightness(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	int rc = -ENXIO;
	struct backlight_device *bd = to_backlight_device(dev);

	mutex_lock(&bd->ops_lock);
	if (bd->ops && bd->ops->get_brightness)
		rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
	mutex_unlock(&bd->ops_lock);

	return rc;
}

static struct class *backlight_class;

#ifdef CONFIG_PM_SLEEP
static int backlight_suspend(struct device *dev)
{
	struct backlight_device *bd = to_backlight_device(dev);

	mutex_lock(&bd->ops_lock);
	if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
		bd->props.state |= BL_CORE_SUSPENDED;
		backlight_update_status(bd);
	}
	mutex_unlock(&bd->ops_lock);

	return 0;
}

static int backlight_resume(struct device *dev)
{
	struct backlight_device *bd = to_backlight_device(dev);

	mutex_lock(&bd->ops_lock);
	if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) {
		bd->props.state &= ~BL_CORE_SUSPENDED;
		backlight_update_status(bd);
	}
	mutex_unlock(&bd->ops_lock);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(backlight_class_dev_pm_ops, backlight_suspend,
			 backlight_resume);

static void bl_device_release(struct device *dev)
{
	struct backlight_device *bd = to_backlight_device(dev);
	kfree(bd);
}

static struct device_attribute bl_device_attributes[] = {
	__ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),
	__ATTR(brightness, 0644, backlight_show_brightness,
		     backlight_store_brightness),
	__ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
		     NULL),
	__ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
	__ATTR(type, 0444, backlight_show_type, NULL),
	__ATTR_NULL,
};

/**
 * backlight_force_update - tell the backlight subsystem that hardware state
 *   has changed
 * @bd: the backlight device to update
 *
 * Updates the internal state of the backlight in response to a hardware event,
 * and generate a uevent to notify userspace
 */
void backlight_force_update(struct backlight_device *bd,
			    enum backlight_update_reason reason)
{
	mutex_lock(&bd->ops_lock);
	if (bd->ops && bd->ops->get_brightness)
		bd->props.brightness = bd->ops->get_brightness(bd);
	mutex_unlock(&bd->ops_lock);
	backlight_generate_event(bd, reason);
}
EXPORT_SYMBOL(backlight_force_update);

/**
 * backlight_device_register - create and register a new object of
 *   backlight_device class.
 * @name: the name of the new object(must be the same as the name of the
 *   respective framebuffer device).
 * @parent: a pointer to the parent device
 * @devdata: an optional pointer to be stored for private driver use. The
 *   methods may retrieve it by using bl_get_data(bd).
 * @ops: the backlight operations structure.
 *
 * Creates and registers new backlight device. Returns either an
 * ERR_PTR() or a pointer to the newly allocated device.
 */
struct backlight_device *backlight_device_register(const char *name,
	struct device *parent, void *devdata, const struct backlight_ops *ops,
	const struct backlight_properties *props)
{
	struct backlight_device *new_bd;
	int rc;

	pr_debug("backlight_device_register: name=%s\n", name);

	new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
	if (!new_bd)
		return ERR_PTR(-ENOMEM);

	mutex_init(&new_bd->update_lock);
	mutex_init(&new_bd->ops_lock);

	new_bd->dev.class = backlight_class;
	new_bd->dev.parent = parent;
	new_bd->dev.release = bl_device_release;
	dev_set_name(&new_bd->dev, "%s", name);
	dev_set_drvdata(&new_bd->dev, devdata);

	/* Set default properties */
	if (props) {
		memcpy(&new_bd->props, props,
		       sizeof(struct backlight_properties));
		if (props->type <= 0 || props->type >= BACKLIGHT_TYPE_MAX) {
			WARN(1, "%s: invalid backlight type", name);
			new_bd->props.type = BACKLIGHT_RAW;
		}
	} else {
		new_bd->props.type = BACKLIGHT_RAW;
	}

	rc = device_register(&new_bd->dev);
	if (rc) {
		kfree(new_bd);
		return ERR_PTR(rc);
	}

	rc = backlight_register_fb(new_bd);
	if (rc) {
		device_unregister(&new_bd->dev);
		return ERR_PTR(rc);
	}

	new_bd->ops = ops;

#ifdef CONFIG_PMAC_BACKLIGHT
	mutex_lock(&pmac_backlight_mutex);
	if (!pmac_backlight)
		pmac_backlight = new_bd;
	mutex_unlock(&pmac_backlight_mutex);
#endif

	return new_bd;
}
EXPORT_SYMBOL(backlight_device_register);

/**
 * backlight_device_unregister - unregisters a backlight device object.
 * @bd: the backlight device object to be unregistered and freed.
 *
 * Unregisters a previously registered via backlight_device_register object.
 */
void backlight_device_unregister(struct backlight_device *bd)
{
	if (!bd)
		return;

#ifdef CONFIG_PMAC_BACKLIGHT
	mutex_lock(&pmac_backlight_mutex);
	if (pmac_backlight == bd)
		pmac_backlight = NULL;
	mutex_unlock(&pmac_backlight_mutex);
#endif
	mutex_lock(&bd->ops_lock);
	bd->ops = NULL;
	mutex_unlock(&bd->ops_lock);

	backlight_unregister_fb(bd);
	device_unregister(&bd->dev);
}
EXPORT_SYMBOL(backlight_device_unregister);

static void devm_backlight_device_release(struct device *dev, void *res)
{
	struct backlight_device *backlight = *(struct backlight_device **)res;

	backlight_device_unregister(backlight);
}

static int devm_backlight_device_match(struct device *dev, void *res,
					void *data)
{
	struct backlight_device **r = res;

	return *r == data;
}

/**
 * devm_backlight_device_register - resource managed backlight_device_register()
 * @dev: the device to register
 * @name: the name of the device
 * @parent: a pointer to the parent device
 * @devdata: an optional pointer to be stored for private driver use
 * @ops: the backlight operations structure
 * @props: the backlight properties
 *
 * @return a struct backlight on success, or an ERR_PTR on error
 *
 * Managed backlight_device_register(). The backlight_device returned
 * from this function are automatically freed on driver detach.
 * See backlight_device_register() for more information.
 */
struct backlight_device *devm_backlight_device_register(struct device *dev,
	const char *name, struct device *parent, void *devdata,
	const struct backlight_ops *ops,
	const struct backlight_properties *props)
{
	struct backlight_device **ptr, *backlight;

	ptr = devres_alloc(devm_backlight_device_release, sizeof(*ptr),
			GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	backlight = backlight_device_register(name, parent, devdata, ops,
						props);
	if (!IS_ERR(backlight)) {
		*ptr = backlight;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return backlight;
}
EXPORT_SYMBOL(devm_backlight_device_register);

/**
 * devm_backlight_device_unregister - resource managed backlight_device_unregister()
 * @dev: the device to unregister
 * @bd: the backlight device to unregister
 *
 * Deallocated a backlight allocated with devm_backlight_device_register().
 * Normally this function will not need to be called and the resource management
 * code will ensure that the resource is freed.
 */
void devm_backlight_device_unregister(struct device *dev,
				struct backlight_device *bd)
{
	int rc;

	rc = devres_release(dev, devm_backlight_device_release,
				devm_backlight_device_match, bd);
	WARN_ON(rc);
}
EXPORT_SYMBOL(devm_backlight_device_unregister);

#ifdef CONFIG_OF
static int of_parent_match(struct device *dev, const void *data)
{
	return dev->parent && dev->parent->of_node == data;
}

/**
 * of_find_backlight_by_node() - find backlight device by device-tree node
 * @node: device-tree node of the backlight device
 *
 * Returns a pointer to the backlight device corresponding to the given DT
 * node or NULL if no such backlight device exists or if the device hasn't
 * been probed yet.
 *
 * This function obtains a reference on the backlight device and it is the
 * caller's responsibility to drop the reference by calling put_device() on
 * the backlight device's .dev field.
 */
struct backlight_device *of_find_backlight_by_node(struct device_node *node)
{
	struct device *dev;

	dev = class_find_device(backlight_class, NULL, node, of_parent_match);

	return dev ? to_backlight_device(dev) : NULL;
}
EXPORT_SYMBOL(of_find_backlight_by_node);
#endif

static void __exit backlight_class_exit(void)
{
	class_destroy(backlight_class);
}

static int __init backlight_class_init(void)
{
	backlight_class = class_create(THIS_MODULE, "backlight");
	if (IS_ERR(backlight_class)) {
		pr_warn("Unable to create backlight class; errno = %ld\n",
			PTR_ERR(backlight_class));
		return PTR_ERR(backlight_class);
	}

	backlight_class->dev_attrs = bl_device_attributes;
	backlight_class->pm = &backlight_class_dev_pm_ops;
	return 0;
}

/*
 * if this is compiled into the kernel, we need to ensure that the
 * class is registered before users of the class try to register lcd's
 */
postcore_initcall(backlight_class_init);
module_exit(backlight_class_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");