1 /* 2 * Backlight Lowlevel Control Abstraction 3 * 4 * Copyright (C) 2003,2004 Hewlett-Packard Company 5 * 6 */ 7 8 #include <linux/module.h> 9 #include <linux/init.h> 10 #include <linux/device.h> 11 #include <linux/backlight.h> 12 #include <linux/notifier.h> 13 #include <linux/ctype.h> 14 #include <linux/err.h> 15 #include <linux/fb.h> 16 17 #ifdef CONFIG_PMAC_BACKLIGHT 18 #include <asm/backlight.h> 19 #endif 20 21 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ 22 defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) 23 /* This callback gets called when something important happens inside a 24 * framebuffer driver. We're looking if that important event is blanking, 25 * and if it is, we're switching backlight power as well ... 26 */ 27 static int fb_notifier_callback(struct notifier_block *self, 28 unsigned long event, void *data) 29 { 30 struct backlight_device *bd; 31 struct fb_event *evdata = data; 32 33 /* If we aren't interested in this event, skip it immediately ... */ 34 if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK) 35 return 0; 36 37 bd = container_of(self, struct backlight_device, fb_notif); 38 mutex_lock(&bd->ops_lock); 39 if (bd->ops) 40 if (!bd->ops->check_fb || 41 bd->ops->check_fb(evdata->info)) { 42 bd->props.fb_blank = *(int *)evdata->data; 43 backlight_update_status(bd); 44 } 45 mutex_unlock(&bd->ops_lock); 46 return 0; 47 } 48 49 static int backlight_register_fb(struct backlight_device *bd) 50 { 51 memset(&bd->fb_notif, 0, sizeof(bd->fb_notif)); 52 bd->fb_notif.notifier_call = fb_notifier_callback; 53 54 return fb_register_client(&bd->fb_notif); 55 } 56 57 static void backlight_unregister_fb(struct backlight_device *bd) 58 { 59 fb_unregister_client(&bd->fb_notif); 60 } 61 #else 62 static inline int backlight_register_fb(struct backlight_device *bd) 63 { 64 return 0; 65 } 66 67 static inline void backlight_unregister_fb(struct backlight_device *bd) 68 { 69 } 70 #endif /* CONFIG_FB */ 71 72 static ssize_t backlight_show_power(struct device *dev, 73 struct device_attribute *attr,char *buf) 74 { 75 struct backlight_device *bd = to_backlight_device(dev); 76 77 return sprintf(buf, "%d\n", bd->props.power); 78 } 79 80 static ssize_t backlight_store_power(struct device *dev, 81 struct device_attribute *attr, const char *buf, size_t count) 82 { 83 int rc = -ENXIO; 84 char *endp; 85 struct backlight_device *bd = to_backlight_device(dev); 86 int power = simple_strtoul(buf, &endp, 0); 87 size_t size = endp - buf; 88 89 if (*endp && isspace(*endp)) 90 size++; 91 if (size != count) 92 return -EINVAL; 93 94 mutex_lock(&bd->ops_lock); 95 if (bd->ops) { 96 pr_debug("backlight: set power to %d\n", power); 97 if (bd->props.power != power) { 98 bd->props.power = power; 99 backlight_update_status(bd); 100 } 101 rc = count; 102 } 103 mutex_unlock(&bd->ops_lock); 104 105 return rc; 106 } 107 108 static ssize_t backlight_show_brightness(struct device *dev, 109 struct device_attribute *attr, char *buf) 110 { 111 struct backlight_device *bd = to_backlight_device(dev); 112 113 return sprintf(buf, "%d\n", bd->props.brightness); 114 } 115 116 static ssize_t backlight_store_brightness(struct device *dev, 117 struct device_attribute *attr, const char *buf, size_t count) 118 { 119 int rc = -ENXIO; 120 char *endp; 121 struct backlight_device *bd = to_backlight_device(dev); 122 int brightness = simple_strtoul(buf, &endp, 0); 123 size_t size = endp - buf; 124 125 if (*endp && isspace(*endp)) 126 size++; 127 if (size != count) 128 return -EINVAL; 129 130 mutex_lock(&bd->ops_lock); 131 if (bd->ops) { 132 if (brightness > bd->props.max_brightness) 133 rc = -EINVAL; 134 else { 135 pr_debug("backlight: set brightness to %d\n", 136 brightness); 137 if (bd->props.brightness != brightness) { 138 bd->props.brightness = brightness; 139 backlight_update_status(bd); 140 } 141 rc = count; 142 } 143 } 144 mutex_unlock(&bd->ops_lock); 145 146 return rc; 147 } 148 149 static ssize_t backlight_show_max_brightness(struct device *dev, 150 struct device_attribute *attr, char *buf) 151 { 152 struct backlight_device *bd = to_backlight_device(dev); 153 154 return sprintf(buf, "%d\n", bd->props.max_brightness); 155 } 156 157 static ssize_t backlight_show_actual_brightness(struct device *dev, 158 struct device_attribute *attr, char *buf) 159 { 160 int rc = -ENXIO; 161 struct backlight_device *bd = to_backlight_device(dev); 162 163 mutex_lock(&bd->ops_lock); 164 if (bd->ops && bd->ops->get_brightness) 165 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd)); 166 mutex_unlock(&bd->ops_lock); 167 168 return rc; 169 } 170 171 static struct class *backlight_class; 172 173 static void bl_device_release(struct device *dev) 174 { 175 struct backlight_device *bd = to_backlight_device(dev); 176 kfree(bd); 177 } 178 179 static struct device_attribute bl_device_attributes[] = { 180 __ATTR(bl_power, 0644, backlight_show_power, backlight_store_power), 181 __ATTR(brightness, 0644, backlight_show_brightness, 182 backlight_store_brightness), 183 __ATTR(actual_brightness, 0444, backlight_show_actual_brightness, 184 NULL), 185 __ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL), 186 __ATTR_NULL, 187 }; 188 189 /** 190 * backlight_device_register - create and register a new object of 191 * backlight_device class. 192 * @name: the name of the new object(must be the same as the name of the 193 * respective framebuffer device). 194 * @devdata: an optional pointer to be stored for private driver use. The 195 * methods may retrieve it by using bl_get_data(bd). 196 * @ops: the backlight operations structure. 197 * 198 * Creates and registers new backlight device. Returns either an 199 * ERR_PTR() or a pointer to the newly allocated device. 200 */ 201 struct backlight_device *backlight_device_register(const char *name, 202 struct device *parent, void *devdata, struct backlight_ops *ops) 203 { 204 struct backlight_device *new_bd; 205 int rc; 206 207 pr_debug("backlight_device_register: name=%s\n", name); 208 209 new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL); 210 if (!new_bd) 211 return ERR_PTR(-ENOMEM); 212 213 mutex_init(&new_bd->update_lock); 214 mutex_init(&new_bd->ops_lock); 215 216 new_bd->dev.class = backlight_class; 217 new_bd->dev.parent = parent; 218 new_bd->dev.release = bl_device_release; 219 strlcpy(new_bd->dev.bus_id, name, BUS_ID_SIZE); 220 dev_set_drvdata(&new_bd->dev, devdata); 221 222 rc = device_register(&new_bd->dev); 223 if (rc) { 224 kfree(new_bd); 225 return ERR_PTR(rc); 226 } 227 228 rc = backlight_register_fb(new_bd); 229 if (rc) { 230 device_unregister(&new_bd->dev); 231 return ERR_PTR(rc); 232 } 233 234 new_bd->ops = ops; 235 236 #ifdef CONFIG_PMAC_BACKLIGHT 237 mutex_lock(&pmac_backlight_mutex); 238 if (!pmac_backlight) 239 pmac_backlight = new_bd; 240 mutex_unlock(&pmac_backlight_mutex); 241 #endif 242 243 return new_bd; 244 } 245 EXPORT_SYMBOL(backlight_device_register); 246 247 /** 248 * backlight_device_unregister - unregisters a backlight device object. 249 * @bd: the backlight device object to be unregistered and freed. 250 * 251 * Unregisters a previously registered via backlight_device_register object. 252 */ 253 void backlight_device_unregister(struct backlight_device *bd) 254 { 255 if (!bd) 256 return; 257 258 #ifdef CONFIG_PMAC_BACKLIGHT 259 mutex_lock(&pmac_backlight_mutex); 260 if (pmac_backlight == bd) 261 pmac_backlight = NULL; 262 mutex_unlock(&pmac_backlight_mutex); 263 #endif 264 mutex_lock(&bd->ops_lock); 265 bd->ops = NULL; 266 mutex_unlock(&bd->ops_lock); 267 268 backlight_unregister_fb(bd); 269 device_unregister(&bd->dev); 270 } 271 EXPORT_SYMBOL(backlight_device_unregister); 272 273 static void __exit backlight_class_exit(void) 274 { 275 class_destroy(backlight_class); 276 } 277 278 static int __init backlight_class_init(void) 279 { 280 backlight_class = class_create(THIS_MODULE, "backlight"); 281 if (IS_ERR(backlight_class)) { 282 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n", 283 PTR_ERR(backlight_class)); 284 return PTR_ERR(backlight_class); 285 } 286 287 backlight_class->dev_attrs = bl_device_attributes; 288 return 0; 289 } 290 291 /* 292 * if this is compiled into the kernel, we need to ensure that the 293 * class is registered before users of the class try to register lcd's 294 */ 295 postcore_initcall(backlight_class_init); 296 module_exit(backlight_class_exit); 297 298 MODULE_LICENSE("GPL"); 299 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 300 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction"); 301