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/mutex.h> 13 #include <linux/notifier.h> 14 15 /* Notes on locking: 16 * 17 * backlight_device->ops_lock is an internal backlight lock protecting the 18 * ops pointer and no code outside the core should need to touch it. 19 * 20 * Access to update_status() is serialised by the update_lock mutex since 21 * most drivers seem to need this and historically get it wrong. 22 * 23 * Most drivers don't need locking on their get_brightness() method. 24 * If yours does, you need to implement it in the driver. You can use the 25 * update_lock mutex if appropriate. 26 * 27 * Any other use of the locks below is probably wrong. 28 */ 29 30 enum backlight_update_reason { 31 BACKLIGHT_UPDATE_HOTKEY, 32 BACKLIGHT_UPDATE_SYSFS, 33 }; 34 35 struct backlight_device; 36 struct fb_info; 37 38 struct backlight_ops { 39 const unsigned int options; 40 41 #define BL_CORE_SUSPENDRESUME (1 << 0) 42 43 /* Notify the backlight driver some property has changed */ 44 int (* const update_status)(struct backlight_device *); 45 /* Return the current backlight brightness (accounting for power, 46 fb_blank etc.) */ 47 int (* const get_brightness)(struct backlight_device *); 48 /* Check if given framebuffer device is the one bound to this backlight; 49 return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */ 50 int (* const check_fb)(struct fb_info *); 51 }; 52 53 /* This structure defines all the properties of a backlight */ 54 struct backlight_properties { 55 /* Current User requested brightness (0 - max_brightness) */ 56 int brightness; 57 /* Maximal value for brightness (read-only) */ 58 int max_brightness; 59 /* Current FB Power mode (0: full on, 1..3: power saving 60 modes; 4: full off), see FB_BLANK_XXX */ 61 int power; 62 /* FB Blanking active? (values as for power) */ 63 /* Due to be removed, please use (state & BL_CORE_FBBLANK) */ 64 int fb_blank; 65 /* Flags used to signal drivers of state changes */ 66 /* Upper 4 bits are reserved for driver internal use */ 67 unsigned int state; 68 69 #define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */ 70 #define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */ 71 #define BL_CORE_DRIVER4 (1 << 28) /* reserved for driver specific use */ 72 #define BL_CORE_DRIVER3 (1 << 29) /* reserved for driver specific use */ 73 #define BL_CORE_DRIVER2 (1 << 30) /* reserved for driver specific use */ 74 #define BL_CORE_DRIVER1 (1 << 31) /* reserved for driver specific use */ 75 76 }; 77 78 struct backlight_device { 79 /* Backlight properties */ 80 struct backlight_properties props; 81 82 /* Serialise access to update_status method */ 83 struct mutex update_lock; 84 85 /* This protects the 'ops' field. If 'ops' is NULL, the driver that 86 registered this device has been unloaded, and if class_get_devdata() 87 points to something in the body of that driver, it is also invalid. */ 88 struct mutex ops_lock; 89 const struct backlight_ops *ops; 90 91 /* The framebuffer notifier block */ 92 struct notifier_block fb_notif; 93 94 struct device dev; 95 }; 96 97 static inline void backlight_update_status(struct backlight_device *bd) 98 { 99 mutex_lock(&bd->update_lock); 100 if (bd->ops && bd->ops->update_status) 101 bd->ops->update_status(bd); 102 mutex_unlock(&bd->update_lock); 103 } 104 105 extern struct backlight_device *backlight_device_register(const char *name, 106 struct device *dev, void *devdata, const struct backlight_ops *ops); 107 extern void backlight_device_unregister(struct backlight_device *bd); 108 extern void backlight_force_update(struct backlight_device *bd, 109 enum backlight_update_reason reason); 110 111 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev) 112 113 static inline void * bl_get_data(struct backlight_device *bl_dev) 114 { 115 return dev_get_drvdata(&bl_dev->dev); 116 } 117 118 struct generic_bl_info { 119 const char *name; 120 int max_intensity; 121 int default_intensity; 122 int limit_mask; 123 void (*set_bl_intensity)(int intensity); 124 void (*kick_battery)(void); 125 }; 126 127 #endif 128