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 enum backlight_type { 36 BACKLIGHT_RAW = 1, 37 BACKLIGHT_PLATFORM, 38 BACKLIGHT_FIRMWARE, 39 BACKLIGHT_TYPE_MAX, 40 }; 41 42 struct backlight_device; 43 struct fb_info; 44 45 struct backlight_ops { 46 unsigned int options; 47 48 #define BL_CORE_SUSPENDRESUME (1 << 0) 49 50 /* Notify the backlight driver some property has changed */ 51 int (*update_status)(struct backlight_device *); 52 /* Return the current backlight brightness (accounting for power, 53 fb_blank etc.) */ 54 int (*get_brightness)(struct backlight_device *); 55 /* Check if given framebuffer device is the one bound to this backlight; 56 return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */ 57 int (*check_fb)(struct backlight_device *, struct fb_info *); 58 }; 59 60 /* This structure defines all the properties of a backlight */ 61 struct backlight_properties { 62 /* Current User requested brightness (0 - max_brightness) */ 63 int brightness; 64 /* Maximal value for brightness (read-only) */ 65 int max_brightness; 66 /* Current FB Power mode (0: full on, 1..3: power saving 67 modes; 4: full off), see FB_BLANK_XXX */ 68 int power; 69 /* FB Blanking active? (values as for power) */ 70 /* Due to be removed, please use (state & BL_CORE_FBBLANK) */ 71 int fb_blank; 72 /* Backlight type */ 73 enum backlight_type type; 74 /* Flags used to signal drivers of state changes */ 75 /* Upper 4 bits are reserved for driver internal use */ 76 unsigned int state; 77 78 #define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */ 79 #define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */ 80 #define BL_CORE_DRIVER4 (1 << 28) /* reserved for driver specific use */ 81 #define BL_CORE_DRIVER3 (1 << 29) /* reserved for driver specific use */ 82 #define BL_CORE_DRIVER2 (1 << 30) /* reserved for driver specific use */ 83 #define BL_CORE_DRIVER1 (1 << 31) /* reserved for driver specific use */ 84 85 }; 86 87 struct backlight_device { 88 /* Backlight properties */ 89 struct backlight_properties props; 90 91 /* Serialise access to update_status method */ 92 struct mutex update_lock; 93 94 /* This protects the 'ops' field. If 'ops' is NULL, the driver that 95 registered this device has been unloaded, and if class_get_devdata() 96 points to something in the body of that driver, it is also invalid. */ 97 struct mutex ops_lock; 98 const struct backlight_ops *ops; 99 100 /* The framebuffer notifier block */ 101 struct notifier_block fb_notif; 102 103 struct device dev; 104 }; 105 106 static inline void backlight_update_status(struct backlight_device *bd) 107 { 108 mutex_lock(&bd->update_lock); 109 if (bd->ops && bd->ops->update_status) 110 bd->ops->update_status(bd); 111 mutex_unlock(&bd->update_lock); 112 } 113 114 extern struct backlight_device *backlight_device_register(const char *name, 115 struct device *dev, void *devdata, const struct backlight_ops *ops, 116 const struct backlight_properties *props); 117 extern struct backlight_device *devm_backlight_device_register( 118 struct device *dev, const char *name, struct device *parent, 119 void *devdata, const struct backlight_ops *ops, 120 const struct backlight_properties *props); 121 extern void backlight_device_unregister(struct backlight_device *bd); 122 extern void devm_backlight_device_unregister(struct device *dev, 123 struct backlight_device *bd); 124 extern void backlight_force_update(struct backlight_device *bd, 125 enum backlight_update_reason reason); 126 127 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev) 128 129 static inline void * bl_get_data(struct backlight_device *bl_dev) 130 { 131 return dev_get_drvdata(&bl_dev->dev); 132 } 133 134 struct generic_bl_info { 135 const char *name; 136 int max_intensity; 137 int default_intensity; 138 int limit_mask; 139 void (*set_bl_intensity)(int intensity); 140 void (*kick_battery)(void); 141 }; 142 143 #ifdef CONFIG_OF 144 struct backlight_device *of_find_backlight_by_node(struct device_node *node); 145 #else 146 static inline struct backlight_device * 147 of_find_backlight_by_node(struct device_node *node) 148 { 149 return NULL; 150 } 151 #endif 152 153 #endif 154