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 * @parent: a pointer to the parent device 195 * @devdata: an optional pointer to be stored for private driver use. The 196 * methods may retrieve it by using bl_get_data(bd). 197 * @ops: the backlight operations structure. 198 * 199 * Creates and registers new backlight device. Returns either an 200 * ERR_PTR() or a pointer to the newly allocated device. 201 */ 202 struct backlight_device *backlight_device_register(const char *name, 203 struct device *parent, void *devdata, struct backlight_ops *ops) 204 { 205 struct backlight_device *new_bd; 206 int rc; 207 208 pr_debug("backlight_device_register: name=%s\n", name); 209 210 new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL); 211 if (!new_bd) 212 return ERR_PTR(-ENOMEM); 213 214 mutex_init(&new_bd->update_lock); 215 mutex_init(&new_bd->ops_lock); 216 217 new_bd->dev.class = backlight_class; 218 new_bd->dev.parent = parent; 219 new_bd->dev.release = bl_device_release; 220 strlcpy(new_bd->dev.bus_id, name, BUS_ID_SIZE); 221 dev_set_drvdata(&new_bd->dev, devdata); 222 223 rc = device_register(&new_bd->dev); 224 if (rc) { 225 kfree(new_bd); 226 return ERR_PTR(rc); 227 } 228 229 rc = backlight_register_fb(new_bd); 230 if (rc) { 231 device_unregister(&new_bd->dev); 232 return ERR_PTR(rc); 233 } 234 235 new_bd->ops = ops; 236 237 #ifdef CONFIG_PMAC_BACKLIGHT 238 mutex_lock(&pmac_backlight_mutex); 239 if (!pmac_backlight) 240 pmac_backlight = new_bd; 241 mutex_unlock(&pmac_backlight_mutex); 242 #endif 243 244 return new_bd; 245 } 246 EXPORT_SYMBOL(backlight_device_register); 247 248 /** 249 * backlight_device_unregister - unregisters a backlight device object. 250 * @bd: the backlight device object to be unregistered and freed. 251 * 252 * Unregisters a previously registered via backlight_device_register object. 253 */ 254 void backlight_device_unregister(struct backlight_device *bd) 255 { 256 if (!bd) 257 return; 258 259 #ifdef CONFIG_PMAC_BACKLIGHT 260 mutex_lock(&pmac_backlight_mutex); 261 if (pmac_backlight == bd) 262 pmac_backlight = NULL; 263 mutex_unlock(&pmac_backlight_mutex); 264 #endif 265 mutex_lock(&bd->ops_lock); 266 bd->ops = NULL; 267 mutex_unlock(&bd->ops_lock); 268 269 backlight_unregister_fb(bd); 270 device_unregister(&bd->dev); 271 } 272 EXPORT_SYMBOL(backlight_device_unregister); 273 274 static void __exit backlight_class_exit(void) 275 { 276 class_destroy(backlight_class); 277 } 278 279 static int __init backlight_class_init(void) 280 { 281 backlight_class = class_create(THIS_MODULE, "backlight"); 282 if (IS_ERR(backlight_class)) { 283 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n", 284 PTR_ERR(backlight_class)); 285 return PTR_ERR(backlight_class); 286 } 287 288 backlight_class->dev_attrs = bl_device_attributes; 289 return 0; 290 } 291 292 /* 293 * if this is compiled into the kernel, we need to ensure that the 294 * class is registered before users of the class try to register lcd's 295 */ 296 postcore_initcall(backlight_class_init); 297 module_exit(backlight_class_exit); 298 299 MODULE_LICENSE("GPL"); 300 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 301 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction"); 302