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1/*
2 * Backlight Lowlevel Control Abstraction
3 *
4 * Copyright (C) 2003,2004 Hewlett-Packard Company
5 *
6 */
7
8#ifndef _LINUX_BACKLIGHT_H
9#define _LINUX_BACKLIGHT_H
10
11#include <linux/device.h>
a55944ca 12#include <linux/fb.h>
28ee086d 13#include <linux/mutex.h>
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14#include <linux/notifier.h>
15
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16/* Notes on locking:
17 *
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18 * backlight_device->ops_lock is an internal backlight lock protecting the
19 * ops pointer and no code outside the core should need to touch it.
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20 *
21 * Access to update_status() is serialised by the update_lock mutex since
22 * most drivers seem to need this and historically get it wrong.
23 *
24 * Most drivers don't need locking on their get_brightness() method.
25 * If yours does, you need to implement it in the driver. You can use the
26 * update_lock mutex if appropriate.
27 *
28 * Any other use of the locks below is probably wrong.
29 */
30
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31enum backlight_update_reason {
32 BACKLIGHT_UPDATE_HOTKEY,
33 BACKLIGHT_UPDATE_SYSFS,
34};
35
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36enum backlight_type {
37 BACKLIGHT_RAW = 1,
38 BACKLIGHT_PLATFORM,
39 BACKLIGHT_FIRMWARE,
40 BACKLIGHT_TYPE_MAX,
41};
42
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43enum backlight_notification {
44 BACKLIGHT_REGISTERED,
45 BACKLIGHT_UNREGISTERED,
46};
47
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48struct backlight_device;
49struct fb_info;
50
599a52d1 51struct backlight_ops {
b4144e4f 52 unsigned int options;
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53
54#define BL_CORE_SUSPENDRESUME (1 << 0)
55
6ca01765 56 /* Notify the backlight driver some property has changed */
b4144e4f 57 int (*update_status)(struct backlight_device *);
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58 /* Return the current backlight brightness (accounting for power,
59 fb_blank etc.) */
b4144e4f 60 int (*get_brightness)(struct backlight_device *);
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61 /* Check if given framebuffer device is the one bound to this backlight;
62 return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
57e148b6 63 int (*check_fb)(struct backlight_device *, struct fb_info *);
599a52d1 64};
6ca01765 65
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66/* This structure defines all the properties of a backlight */
67struct backlight_properties {
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68 /* Current User requested brightness (0 - max_brightness) */
69 int brightness;
70 /* Maximal value for brightness (read-only) */
71 int max_brightness;
72 /* Current FB Power mode (0: full on, 1..3: power saving
73 modes; 4: full off), see FB_BLANK_XXX */
74 int power;
75 /* FB Blanking active? (values as for power) */
c835ee7f 76 /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
6ca01765 77 int fb_blank;
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78 /* Backlight type */
79 enum backlight_type type;
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80 /* Flags used to signal drivers of state changes */
81 /* Upper 4 bits are reserved for driver internal use */
82 unsigned int state;
83
84#define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
85#define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
86#define BL_CORE_DRIVER4 (1 << 28) /* reserved for driver specific use */
87#define BL_CORE_DRIVER3 (1 << 29) /* reserved for driver specific use */
88#define BL_CORE_DRIVER2 (1 << 30) /* reserved for driver specific use */
89#define BL_CORE_DRIVER1 (1 << 31) /* reserved for driver specific use */
90
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91};
92
93struct backlight_device {
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94 /* Backlight properties */
95 struct backlight_properties props;
96
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97 /* Serialise access to update_status method */
98 struct mutex update_lock;
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99
100 /* This protects the 'ops' field. If 'ops' is NULL, the driver that
101 registered this device has been unloaded, and if class_get_devdata()
102 points to something in the body of that driver, it is also invalid. */
103 struct mutex ops_lock;
9905a43b 104 const struct backlight_ops *ops;
599a52d1 105
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106 /* The framebuffer notifier block */
107 struct notifier_block fb_notif;
655bfd7a 108
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109 /* list entry of all registered backlight devices */
110 struct list_head entry;
111
655bfd7a 112 struct device dev;
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113
114 /* Multiple framebuffers may share one backlight device */
115 bool fb_bl_on[FB_MAX];
116
117 int use_count;
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118};
119
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120static inline void backlight_update_status(struct backlight_device *bd)
121{
122 mutex_lock(&bd->update_lock);
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123 if (bd->ops && bd->ops->update_status)
124 bd->ops->update_status(bd);
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125 mutex_unlock(&bd->update_lock);
126}
127
1da177e4 128extern struct backlight_device *backlight_device_register(const char *name,
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129 struct device *dev, void *devdata, const struct backlight_ops *ops,
130 const struct backlight_properties *props);
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131extern struct backlight_device *devm_backlight_device_register(
132 struct device *dev, const char *name, struct device *parent,
133 void *devdata, const struct backlight_ops *ops,
134 const struct backlight_properties *props);
1da177e4 135extern void backlight_device_unregister(struct backlight_device *bd);
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136extern void devm_backlight_device_unregister(struct device *dev,
137 struct backlight_device *bd);
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138extern void backlight_force_update(struct backlight_device *bd,
139 enum backlight_update_reason reason);
5915a3db 140extern bool backlight_device_registered(enum backlight_type type);
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141extern int backlight_register_notifier(struct notifier_block *nb);
142extern int backlight_unregister_notifier(struct notifier_block *nb);
1da177e4 143
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144#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)
145
146static inline void * bl_get_data(struct backlight_device *bl_dev)
147{
148 return dev_get_drvdata(&bl_dev->dev);
149}
1da177e4 150
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151struct generic_bl_info {
152 const char *name;
153 int max_intensity;
154 int default_intensity;
155 int limit_mask;
156 void (*set_bl_intensity)(int intensity);
157 void (*kick_battery)(void);
158};
159
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160#ifdef CONFIG_OF
161struct backlight_device *of_find_backlight_by_node(struct device_node *node);
162#else
163static inline struct backlight_device *
164of_find_backlight_by_node(struct device_node *node)
165{
166 return NULL;
167}
168#endif
169
1da177e4 170#endif