1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Backlight Lowlevel Control Abstraction 4 * 5 * Copyright (C) 2003,2004 Hewlett-Packard Company 6 * 7 */ 8 9 #ifndef _LINUX_BACKLIGHT_H 10 #define _LINUX_BACKLIGHT_H 11 12 #include <linux/device.h> 13 #include <linux/fb.h> 14 #include <linux/mutex.h> 15 #include <linux/notifier.h> 16 17 /* Notes on locking: 18 * 19 * backlight_device->ops_lock is an internal backlight lock protecting the 20 * ops pointer and no code outside the core should need to touch it. 21 * 22 * Access to update_status() is serialised by the update_lock mutex since 23 * most drivers seem to need this and historically get it wrong. 24 * 25 * Most drivers don't need locking on their get_brightness() method. 26 * If yours does, you need to implement it in the driver. You can use the 27 * update_lock mutex if appropriate. 28 * 29 * Any other use of the locks below is probably wrong. 30 */ 31 32 enum backlight_update_reason { 33 BACKLIGHT_UPDATE_HOTKEY, 34 BACKLIGHT_UPDATE_SYSFS, 35 }; 36 37 enum backlight_type { 38 BACKLIGHT_RAW = 1, 39 BACKLIGHT_PLATFORM, 40 BACKLIGHT_FIRMWARE, 41 BACKLIGHT_TYPE_MAX, 42 }; 43 44 enum backlight_notification { 45 BACKLIGHT_REGISTERED, 46 BACKLIGHT_UNREGISTERED, 47 }; 48 49 struct backlight_device; 50 struct fb_info; 51 52 struct backlight_ops { 53 unsigned int options; 54 55 #define BL_CORE_SUSPENDRESUME (1 << 0) 56 57 /* Notify the backlight driver some property has changed */ 58 int (*update_status)(struct backlight_device *); 59 /* Return the current backlight brightness (accounting for power, 60 fb_blank etc.) */ 61 int (*get_brightness)(struct backlight_device *); 62 /* Check if given framebuffer device is the one bound to this backlight; 63 return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */ 64 int (*check_fb)(struct backlight_device *, struct fb_info *); 65 }; 66 67 /* This structure defines all the properties of a backlight */ 68 struct backlight_properties { 69 /* Current User requested brightness (0 - max_brightness) */ 70 int brightness; 71 /* Maximal value for brightness (read-only) */ 72 int max_brightness; 73 /* Current FB Power mode (0: full on, 1..3: power saving 74 modes; 4: full off), see FB_BLANK_XXX */ 75 int power; 76 /* FB Blanking active? (values as for power) */ 77 /* Due to be removed, please use (state & BL_CORE_FBBLANK) */ 78 int fb_blank; 79 /* Backlight type */ 80 enum backlight_type type; 81 /* Flags used to signal drivers of state changes */ 82 /* Upper 4 bits are reserved for driver internal use */ 83 unsigned int state; 84 85 #define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */ 86 #define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */ 87 #define BL_CORE_DRIVER1 (1 << 31) /* reserved for driver specific use */ 88 89 }; 90 91 struct backlight_device { 92 /* Backlight properties */ 93 struct backlight_properties props; 94 95 /* Serialise access to update_status method */ 96 struct mutex update_lock; 97 98 /* This protects the 'ops' field. If 'ops' is NULL, the driver that 99 registered this device has been unloaded, and if class_get_devdata() 100 points to something in the body of that driver, it is also invalid. */ 101 struct mutex ops_lock; 102 const struct backlight_ops *ops; 103 104 /* The framebuffer notifier block */ 105 struct notifier_block fb_notif; 106 107 /* list entry of all registered backlight devices */ 108 struct list_head entry; 109 110 struct device dev; 111 112 /* Multiple framebuffers may share one backlight device */ 113 bool fb_bl_on[FB_MAX]; 114 115 int use_count; 116 }; 117 118 static inline int backlight_update_status(struct backlight_device *bd) 119 { 120 int ret = -ENOENT; 121 122 mutex_lock(&bd->update_lock); 123 if (bd->ops && bd->ops->update_status) 124 ret = bd->ops->update_status(bd); 125 mutex_unlock(&bd->update_lock); 126 127 return ret; 128 } 129 130 /** 131 * backlight_enable - Enable backlight 132 * @bd: the backlight device to enable 133 */ 134 static inline int backlight_enable(struct backlight_device *bd) 135 { 136 if (!bd) 137 return 0; 138 139 bd->props.power = FB_BLANK_UNBLANK; 140 bd->props.fb_blank = FB_BLANK_UNBLANK; 141 bd->props.state &= ~BL_CORE_FBBLANK; 142 143 return backlight_update_status(bd); 144 } 145 146 /** 147 * backlight_disable - Disable backlight 148 * @bd: the backlight device to disable 149 */ 150 static inline int backlight_disable(struct backlight_device *bd) 151 { 152 if (!bd) 153 return 0; 154 155 bd->props.power = FB_BLANK_POWERDOWN; 156 bd->props.fb_blank = FB_BLANK_POWERDOWN; 157 bd->props.state |= BL_CORE_FBBLANK; 158 159 return backlight_update_status(bd); 160 } 161 162 /** 163 * backlight_put - Drop backlight reference 164 * @bd: the backlight device to put 165 */ 166 static inline void backlight_put(struct backlight_device *bd) 167 { 168 if (bd) 169 put_device(&bd->dev); 170 } 171 172 extern struct backlight_device *backlight_device_register(const char *name, 173 struct device *dev, void *devdata, const struct backlight_ops *ops, 174 const struct backlight_properties *props); 175 extern struct backlight_device *devm_backlight_device_register( 176 struct device *dev, const char *name, struct device *parent, 177 void *devdata, const struct backlight_ops *ops, 178 const struct backlight_properties *props); 179 extern void backlight_device_unregister(struct backlight_device *bd); 180 extern void devm_backlight_device_unregister(struct device *dev, 181 struct backlight_device *bd); 182 extern void backlight_force_update(struct backlight_device *bd, 183 enum backlight_update_reason reason); 184 extern int backlight_register_notifier(struct notifier_block *nb); 185 extern int backlight_unregister_notifier(struct notifier_block *nb); 186 extern struct backlight_device *backlight_device_get_by_type(enum backlight_type type); 187 extern int backlight_device_set_brightness(struct backlight_device *bd, unsigned long brightness); 188 189 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev) 190 191 static inline void * bl_get_data(struct backlight_device *bl_dev) 192 { 193 return dev_get_drvdata(&bl_dev->dev); 194 } 195 196 struct generic_bl_info { 197 const char *name; 198 int max_intensity; 199 int default_intensity; 200 int limit_mask; 201 void (*set_bl_intensity)(int intensity); 202 void (*kick_battery)(void); 203 }; 204 205 #ifdef CONFIG_OF 206 struct backlight_device *of_find_backlight_by_node(struct device_node *node); 207 #else 208 static inline struct backlight_device * 209 of_find_backlight_by_node(struct device_node *node) 210 { 211 return NULL; 212 } 213 #endif 214 215 #if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE) 216 struct backlight_device *of_find_backlight(struct device *dev); 217 struct backlight_device *devm_of_find_backlight(struct device *dev); 218 #else 219 static inline struct backlight_device *of_find_backlight(struct device *dev) 220 { 221 return NULL; 222 } 223 224 static inline struct backlight_device * 225 devm_of_find_backlight(struct device *dev) 226 { 227 return NULL; 228 } 229 #endif 230 231 #endif 232