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 if (bd->props.fb_blank == FB_BLANK_UNBLANK) 44 bd->props.state &= ~BL_CORE_FBBLANK; 45 else 46 bd->props.state |= BL_CORE_FBBLANK; 47 backlight_update_status(bd); 48 } 49 mutex_unlock(&bd->ops_lock); 50 return 0; 51 } 52 53 static int backlight_register_fb(struct backlight_device *bd) 54 { 55 memset(&bd->fb_notif, 0, sizeof(bd->fb_notif)); 56 bd->fb_notif.notifier_call = fb_notifier_callback; 57 58 return fb_register_client(&bd->fb_notif); 59 } 60 61 static void backlight_unregister_fb(struct backlight_device *bd) 62 { 63 fb_unregister_client(&bd->fb_notif); 64 } 65 #else 66 static inline int backlight_register_fb(struct backlight_device *bd) 67 { 68 return 0; 69 } 70 71 static inline void backlight_unregister_fb(struct backlight_device *bd) 72 { 73 } 74 #endif /* CONFIG_FB */ 75 76 static ssize_t backlight_show_power(struct device *dev, 77 struct device_attribute *attr,char *buf) 78 { 79 struct backlight_device *bd = to_backlight_device(dev); 80 81 return sprintf(buf, "%d\n", bd->props.power); 82 } 83 84 static ssize_t backlight_store_power(struct device *dev, 85 struct device_attribute *attr, const char *buf, size_t count) 86 { 87 int rc; 88 struct backlight_device *bd = to_backlight_device(dev); 89 unsigned long power; 90 91 rc = strict_strtoul(buf, 0, &power); 92 if (rc) 93 return rc; 94 95 rc = -ENXIO; 96 mutex_lock(&bd->ops_lock); 97 if (bd->ops) { 98 pr_debug("backlight: set power to %lu\n", power); 99 if (bd->props.power != power) { 100 bd->props.power = power; 101 backlight_update_status(bd); 102 } 103 rc = count; 104 } 105 mutex_unlock(&bd->ops_lock); 106 107 return rc; 108 } 109 110 static ssize_t backlight_show_brightness(struct device *dev, 111 struct device_attribute *attr, char *buf) 112 { 113 struct backlight_device *bd = to_backlight_device(dev); 114 115 return sprintf(buf, "%d\n", bd->props.brightness); 116 } 117 118 static ssize_t backlight_store_brightness(struct device *dev, 119 struct device_attribute *attr, const char *buf, size_t count) 120 { 121 int rc; 122 struct backlight_device *bd = to_backlight_device(dev); 123 unsigned long brightness; 124 125 rc = strict_strtoul(buf, 0, &brightness); 126 if (rc) 127 return rc; 128 129 rc = -ENXIO; 130 131 mutex_lock(&bd->ops_lock); 132 if (bd->ops) { 133 if (brightness > bd->props.max_brightness) 134 rc = -EINVAL; 135 else { 136 pr_debug("backlight: set brightness to %lu\n", 137 brightness); 138 bd->props.brightness = brightness; 139 backlight_update_status(bd); 140 rc = count; 141 } 142 } 143 mutex_unlock(&bd->ops_lock); 144 145 return rc; 146 } 147 148 static ssize_t backlight_show_max_brightness(struct device *dev, 149 struct device_attribute *attr, char *buf) 150 { 151 struct backlight_device *bd = to_backlight_device(dev); 152 153 return sprintf(buf, "%d\n", bd->props.max_brightness); 154 } 155 156 static ssize_t backlight_show_actual_brightness(struct device *dev, 157 struct device_attribute *attr, char *buf) 158 { 159 int rc = -ENXIO; 160 struct backlight_device *bd = to_backlight_device(dev); 161 162 mutex_lock(&bd->ops_lock); 163 if (bd->ops && bd->ops->get_brightness) 164 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd)); 165 mutex_unlock(&bd->ops_lock); 166 167 return rc; 168 } 169 170 static struct class *backlight_class; 171 172 static int backlight_suspend(struct device *dev, pm_message_t state) 173 { 174 struct backlight_device *bd = to_backlight_device(dev); 175 176 if (bd->ops->options & BL_CORE_SUSPENDRESUME) { 177 mutex_lock(&bd->ops_lock); 178 bd->props.state |= BL_CORE_SUSPENDED; 179 backlight_update_status(bd); 180 mutex_unlock(&bd->ops_lock); 181 } 182 183 return 0; 184 } 185 186 static int backlight_resume(struct device *dev) 187 { 188 struct backlight_device *bd = to_backlight_device(dev); 189 190 if (bd->ops->options & BL_CORE_SUSPENDRESUME) { 191 mutex_lock(&bd->ops_lock); 192 bd->props.state &= ~BL_CORE_SUSPENDED; 193 backlight_update_status(bd); 194 mutex_unlock(&bd->ops_lock); 195 } 196 197 return 0; 198 } 199 200 static void bl_device_release(struct device *dev) 201 { 202 struct backlight_device *bd = to_backlight_device(dev); 203 kfree(bd); 204 } 205 206 static struct device_attribute bl_device_attributes[] = { 207 __ATTR(bl_power, 0644, backlight_show_power, backlight_store_power), 208 __ATTR(brightness, 0644, backlight_show_brightness, 209 backlight_store_brightness), 210 __ATTR(actual_brightness, 0444, backlight_show_actual_brightness, 211 NULL), 212 __ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL), 213 __ATTR_NULL, 214 }; 215 216 /** 217 * backlight_device_register - create and register a new object of 218 * backlight_device class. 219 * @name: the name of the new object(must be the same as the name of the 220 * respective framebuffer device). 221 * @parent: a pointer to the parent device 222 * @devdata: an optional pointer to be stored for private driver use. The 223 * methods may retrieve it by using bl_get_data(bd). 224 * @ops: the backlight operations structure. 225 * 226 * Creates and registers new backlight device. Returns either an 227 * ERR_PTR() or a pointer to the newly allocated device. 228 */ 229 struct backlight_device *backlight_device_register(const char *name, 230 struct device *parent, void *devdata, struct backlight_ops *ops) 231 { 232 struct backlight_device *new_bd; 233 int rc; 234 235 pr_debug("backlight_device_register: name=%s\n", name); 236 237 new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL); 238 if (!new_bd) 239 return ERR_PTR(-ENOMEM); 240 241 mutex_init(&new_bd->update_lock); 242 mutex_init(&new_bd->ops_lock); 243 244 new_bd->dev.class = backlight_class; 245 new_bd->dev.parent = parent; 246 new_bd->dev.release = bl_device_release; 247 dev_set_name(&new_bd->dev, name); 248 dev_set_drvdata(&new_bd->dev, devdata); 249 250 rc = device_register(&new_bd->dev); 251 if (rc) { 252 kfree(new_bd); 253 return ERR_PTR(rc); 254 } 255 256 rc = backlight_register_fb(new_bd); 257 if (rc) { 258 device_unregister(&new_bd->dev); 259 return ERR_PTR(rc); 260 } 261 262 new_bd->ops = ops; 263 264 #ifdef CONFIG_PMAC_BACKLIGHT 265 mutex_lock(&pmac_backlight_mutex); 266 if (!pmac_backlight) 267 pmac_backlight = new_bd; 268 mutex_unlock(&pmac_backlight_mutex); 269 #endif 270 271 return new_bd; 272 } 273 EXPORT_SYMBOL(backlight_device_register); 274 275 /** 276 * backlight_device_unregister - unregisters a backlight device object. 277 * @bd: the backlight device object to be unregistered and freed. 278 * 279 * Unregisters a previously registered via backlight_device_register object. 280 */ 281 void backlight_device_unregister(struct backlight_device *bd) 282 { 283 if (!bd) 284 return; 285 286 #ifdef CONFIG_PMAC_BACKLIGHT 287 mutex_lock(&pmac_backlight_mutex); 288 if (pmac_backlight == bd) 289 pmac_backlight = NULL; 290 mutex_unlock(&pmac_backlight_mutex); 291 #endif 292 mutex_lock(&bd->ops_lock); 293 bd->ops = NULL; 294 mutex_unlock(&bd->ops_lock); 295 296 backlight_unregister_fb(bd); 297 device_unregister(&bd->dev); 298 } 299 EXPORT_SYMBOL(backlight_device_unregister); 300 301 static void __exit backlight_class_exit(void) 302 { 303 class_destroy(backlight_class); 304 } 305 306 static int __init backlight_class_init(void) 307 { 308 backlight_class = class_create(THIS_MODULE, "backlight"); 309 if (IS_ERR(backlight_class)) { 310 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n", 311 PTR_ERR(backlight_class)); 312 return PTR_ERR(backlight_class); 313 } 314 315 backlight_class->dev_attrs = bl_device_attributes; 316 backlight_class->suspend = backlight_suspend; 317 backlight_class->resume = backlight_resume; 318 return 0; 319 } 320 321 /* 322 * if this is compiled into the kernel, we need to ensure that the 323 * class is registered before users of the class try to register lcd's 324 */ 325 postcore_initcall(backlight_class_init); 326 module_exit(backlight_class_exit); 327 328 MODULE_LICENSE("GPL"); 329 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 330 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction"); 331