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 31 enum backlight_update_reason { 32 BACKLIGHT_UPDATE_HOTKEY, 33 BACKLIGHT_UPDATE_SYSFS, 34 }; 35 36 enum backlight_type { 37 BACKLIGHT_RAW = 1, 38 BACKLIGHT_PLATFORM, 39 BACKLIGHT_FIRMWARE, 40 BACKLIGHT_TYPE_MAX, 41 }; 42 43 enum backlight_notification { 44 BACKLIGHT_REGISTERED, 45 BACKLIGHT_UNREGISTERED, 46 }; 47 48 struct backlight_device; 49 struct fb_info; 50 51 struct 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 */ 67 struct 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 93 struct 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 }; 119 120 static inline int backlight_update_status(struct backlight_device *bd) 121 { 122 int ret = -ENOENT; 123 124 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 } 131 132 extern struct backlight_device *backlight_device_register(const char *name, 133 struct device *dev, void *devdata, const struct backlight_ops *ops, 134 const struct backlight_properties *props); 135 extern struct backlight_device *devm_backlight_device_register( 136 struct device *dev, const char *name, struct device *parent, 137 void *devdata, const struct backlight_ops *ops, 138 const struct backlight_properties *props); 139 extern void backlight_device_unregister(struct backlight_device *bd); 140 extern void devm_backlight_device_unregister(struct device *dev, 141 struct backlight_device *bd); 142 extern void backlight_force_update(struct backlight_device *bd, 143 enum backlight_update_reason reason); 144 extern int backlight_register_notifier(struct notifier_block *nb); 145 extern int backlight_unregister_notifier(struct notifier_block *nb); 146 extern struct backlight_device *backlight_device_get_by_type(enum backlight_type type); 147 extern int backlight_device_set_brightness(struct backlight_device *bd, unsigned long brightness); 148 149 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev) 150 151 static inline void * bl_get_data(struct backlight_device *bl_dev) 152 { 153 return dev_get_drvdata(&bl_dev->dev); 154 } 155 156 struct generic_bl_info { 157 const char *name; 158 int max_intensity; 159 int default_intensity; 160 int limit_mask; 161 void (*set_bl_intensity)(int intensity); 162 void (*kick_battery)(void); 163 }; 164 165 #ifdef CONFIG_OF 166 struct backlight_device *of_find_backlight_by_node(struct device_node *node); 167 #else 168 static inline struct backlight_device * 169 of_find_backlight_by_node(struct device_node *node) 170 { 171 return NULL; 172 } 173 #endif 174 175 #endif 176