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>
12#include <linux/fb.h>
13#include <linux/mutex.h>
14#include <linux/notifier.h>
15
16/* Notes on locking:
17 *
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.
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
31enum backlight_update_reason {
32	BACKLIGHT_UPDATE_HOTKEY,
33	BACKLIGHT_UPDATE_SYSFS,
34};
35
36enum backlight_type {
37	BACKLIGHT_RAW = 1,
38	BACKLIGHT_PLATFORM,
39	BACKLIGHT_FIRMWARE,
40	BACKLIGHT_TYPE_MAX,
41};
42
43enum backlight_notification {
44	BACKLIGHT_REGISTERED,
45	BACKLIGHT_UNREGISTERED,
46};
47
48struct backlight_device;
49struct fb_info;
50
51struct backlight_ops {
52	unsigned int options;
53
54#define BL_CORE_SUSPENDRESUME	(1 << 0)
55
56	/* Notify the backlight driver some property has changed */
57	int (*update_status)(struct backlight_device *);
58	/* Return the current backlight brightness (accounting for power,
59	   fb_blank etc.) */
60	int (*get_brightness)(struct backlight_device *);
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. */
63	int (*check_fb)(struct backlight_device *, struct fb_info *);
64};
65
66/* This structure defines all the properties of a backlight */
67struct backlight_properties {
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) */
76	/* Due to be removed, please use (state & BL_CORE_FBBLANK) */
77	int fb_blank;
78	/* Backlight type */
79	enum backlight_type type;
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
91};
92
93struct backlight_device {
94	/* Backlight properties */
95	struct backlight_properties props;
96
97	/* Serialise access to update_status method */
98	struct mutex update_lock;
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;
104	const struct backlight_ops *ops;
105
106	/* The framebuffer notifier block */
107	struct notifier_block fb_notif;
108
109	/* list entry of all registered backlight devices */
110	struct list_head entry;
111
112	struct device dev;
113
114	/* Multiple framebuffers may share one backlight device */
115	bool fb_bl_on[FB_MAX];
116
117	int use_count;
118};
119
120static inline void backlight_update_status(struct backlight_device *bd)
121{
122	mutex_lock(&bd->update_lock);
123	if (bd->ops && bd->ops->update_status)
124		bd->ops->update_status(bd);
125	mutex_unlock(&bd->update_lock);
126}
127
128extern struct backlight_device *backlight_device_register(const char *name,
129	struct device *dev, void *devdata, const struct backlight_ops *ops,
130	const struct backlight_properties *props);
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);
135extern void backlight_device_unregister(struct backlight_device *bd);
136extern void devm_backlight_device_unregister(struct device *dev,
137					struct backlight_device *bd);
138extern void backlight_force_update(struct backlight_device *bd,
139				   enum backlight_update_reason reason);
140extern bool backlight_device_registered(enum backlight_type type);
141extern int backlight_register_notifier(struct notifier_block *nb);
142extern int backlight_unregister_notifier(struct notifier_block *nb);
143
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}
150
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
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
170#endif
171