backlight.h 5.14 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4 5 6 7 8 9 10 11
/*
 * Backlight Lowlevel Control Abstraction
 *
 * Copyright (C) 2003,2004 Hewlett-Packard Company
 *
 */

#ifndef _LINUX_BACKLIGHT_H
#define _LINUX_BACKLIGHT_H

#include <linux/device.h>
12
#include <linux/fb.h>
13
#include <linux/mutex.h>
Linus Torvalds's avatar
Linus Torvalds committed
14 15
#include <linux/notifier.h>

16 17
/* Notes on locking:
 *
18 19
 * backlight_device->ops_lock is an internal backlight lock protecting the
 * ops pointer and no code outside the core should need to touch it.
20 21 22 23 24 25 26 27 28 29 30
 *
 * Access to update_status() is serialised by the update_lock mutex since
 * most drivers seem to need this and historically get it wrong.
 *
 * Most drivers don't need locking on their get_brightness() method.
 * If yours does, you need to implement it in the driver. You can use the
 * update_lock mutex if appropriate.
 *
 * Any other use of the locks below is probably wrong.
 */

31 32 33 34 35
enum backlight_update_reason {
	BACKLIGHT_UPDATE_HOTKEY,
	BACKLIGHT_UPDATE_SYSFS,
};

36 37 38 39 40 41 42
enum backlight_type {
	BACKLIGHT_RAW = 1,
	BACKLIGHT_PLATFORM,
	BACKLIGHT_FIRMWARE,
	BACKLIGHT_TYPE_MAX,
};

43 44 45 46 47
enum backlight_notification {
	BACKLIGHT_REGISTERED,
	BACKLIGHT_UNREGISTERED,
};

Linus Torvalds's avatar
Linus Torvalds committed
48 49 50
struct backlight_device;
struct fb_info;

51
struct backlight_ops {
52
	unsigned int options;
53 54 55

#define BL_CORE_SUSPENDRESUME	(1 << 0)

56
	/* Notify the backlight driver some property has changed */
57
	int (*update_status)(struct backlight_device *);
58 59
	/* Return the current backlight brightness (accounting for power,
	   fb_blank etc.) */
60
	int (*get_brightness)(struct backlight_device *);
Linus Torvalds's avatar
Linus Torvalds committed
61 62
	/* Check if given framebuffer device is the one bound to this backlight;
	   return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
63
	int (*check_fb)(struct backlight_device *, struct fb_info *);
64
};
65

66 67
/* This structure defines all the properties of a backlight */
struct backlight_properties {
68 69 70 71 72 73 74 75
	/* Current User requested brightness (0 - max_brightness) */
	int brightness;
	/* Maximal value for brightness (read-only) */
	int max_brightness;
	/* Current FB Power mode (0: full on, 1..3: power saving
	   modes; 4: full off), see FB_BLANK_XXX */
	int power;
	/* FB Blanking active? (values as for power) */
76
	/* Due to be removed, please use (state & BL_CORE_FBBLANK) */
77
	int fb_blank;
78 79
	/* Backlight type */
	enum backlight_type type;
80 81 82 83 84 85 86 87 88 89 90
	/* Flags used to signal drivers of state changes */
	/* Upper 4 bits are reserved for driver internal use */
	unsigned int state;

#define BL_CORE_SUSPENDED	(1 << 0)	/* backlight is suspended */
#define BL_CORE_FBBLANK		(1 << 1)	/* backlight is under an fb blank event */
#define BL_CORE_DRIVER4		(1 << 28)	/* reserved for driver specific use */
#define BL_CORE_DRIVER3		(1 << 29)	/* reserved for driver specific use */
#define BL_CORE_DRIVER2		(1 << 30)	/* reserved for driver specific use */
#define BL_CORE_DRIVER1		(1 << 31)	/* reserved for driver specific use */

Linus Torvalds's avatar
Linus Torvalds committed
91 92 93
};

struct backlight_device {
94 95 96
	/* Backlight properties */
	struct backlight_properties props;

97 98
	/* Serialise access to update_status method */
	struct mutex update_lock;
99 100 101 102 103

	/* This protects the 'ops' field. If 'ops' is NULL, the driver that
	   registered this device has been unloaded, and if class_get_devdata()
	   points to something in the body of that driver, it is also invalid. */
	struct mutex ops_lock;
104
	const struct backlight_ops *ops;
105

Linus Torvalds's avatar
Linus Torvalds committed
106 107
	/* The framebuffer notifier block */
	struct notifier_block fb_notif;
108

109 110 111
	/* list entry of all registered backlight devices */
	struct list_head entry;

112
	struct device dev;
113 114 115 116 117

	/* Multiple framebuffers may share one backlight device */
	bool fb_bl_on[FB_MAX];

	int use_count;
Linus Torvalds's avatar
Linus Torvalds committed
118 119
};

120
static inline int backlight_update_status(struct backlight_device *bd)
121
{
122 123
	int ret = -ENOENT;

124
	mutex_lock(&bd->update_lock);
125
	if (bd->ops && bd->ops->update_status)
126
		ret = bd->ops->update_status(bd);
127
	mutex_unlock(&bd->update_lock);
128 129

	return ret;
130 131
}

Linus Torvalds's avatar
Linus Torvalds committed
132
extern struct backlight_device *backlight_device_register(const char *name,
133 134
	struct device *dev, void *devdata, const struct backlight_ops *ops,
	const struct backlight_properties *props);
135 136 137 138
extern 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);
Linus Torvalds's avatar
Linus Torvalds committed
139
extern void backlight_device_unregister(struct backlight_device *bd);
140 141
extern void devm_backlight_device_unregister(struct device *dev,
					struct backlight_device *bd);
142 143
extern void backlight_force_update(struct backlight_device *bd,
				   enum backlight_update_reason reason);
144
extern bool backlight_device_registered(enum backlight_type type);
145 146
extern int backlight_register_notifier(struct notifier_block *nb);
extern int backlight_unregister_notifier(struct notifier_block *nb);
Linus Torvalds's avatar
Linus Torvalds committed
147

148 149 150 151 152 153
#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)

static inline void * bl_get_data(struct backlight_device *bl_dev)
{
	return dev_get_drvdata(&bl_dev->dev);
}
Linus Torvalds's avatar
Linus Torvalds committed
154

155 156 157 158 159 160 161 162 163
struct generic_bl_info {
	const char *name;
	int max_intensity;
	int default_intensity;
	int limit_mask;
	void (*set_bl_intensity)(int intensity);
	void (*kick_battery)(void);
};

164 165 166 167 168 169 170 171 172 173
#ifdef CONFIG_OF
struct backlight_device *of_find_backlight_by_node(struct device_node *node);
#else
static inline struct backlight_device *
of_find_backlight_by_node(struct device_node *node)
{
	return NULL;
}
#endif

Linus Torvalds's avatar
Linus Torvalds committed
174
#endif