1 /* 2 * Backlight Lowlevel Control Abstraction 3 * 4 * Copyright (C) 2003,2004 Hewlett-Packard Company 5 * 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/module.h> 11 #include <linux/init.h> 12 #include <linux/device.h> 13 #include <linux/backlight.h> 14 #include <linux/notifier.h> 15 #include <linux/ctype.h> 16 #include <linux/err.h> 17 #include <linux/fb.h> 18 #include <linux/slab.h> 19 20 #ifdef CONFIG_PMAC_BACKLIGHT 21 #include <asm/backlight.h> 22 #endif 23 24 static const char *const backlight_types[] = { 25 [BACKLIGHT_RAW] = "raw", 26 [BACKLIGHT_PLATFORM] = "platform", 27 [BACKLIGHT_FIRMWARE] = "firmware", 28 }; 29 30 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ 31 defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) 32 /* This callback gets called when something important happens inside a 33 * framebuffer driver. We're looking if that important event is blanking, 34 * and if it is, we're switching backlight power as well ... 35 */ 36 static int fb_notifier_callback(struct notifier_block *self, 37 unsigned long event, void *data) 38 { 39 struct backlight_device *bd; 40 struct fb_event *evdata = data; 41 42 /* If we aren't interested in this event, skip it immediately ... */ 43 if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK) 44 return 0; 45 46 bd = container_of(self, struct backlight_device, fb_notif); 47 mutex_lock(&bd->ops_lock); 48 if (bd->ops) 49 if (!bd->ops->check_fb || 50 bd->ops->check_fb(bd, evdata->info)) { 51 bd->props.fb_blank = *(int *)evdata->data; 52 if (bd->props.fb_blank == FB_BLANK_UNBLANK) 53 bd->props.state &= ~BL_CORE_FBBLANK; 54 else 55 bd->props.state |= BL_CORE_FBBLANK; 56 backlight_update_status(bd); 57 } 58 mutex_unlock(&bd->ops_lock); 59 return 0; 60 } 61 62 static int backlight_register_fb(struct backlight_device *bd) 63 { 64 memset(&bd->fb_notif, 0, sizeof(bd->fb_notif)); 65 bd->fb_notif.notifier_call = fb_notifier_callback; 66 67 return fb_register_client(&bd->fb_notif); 68 } 69 70 static void backlight_unregister_fb(struct backlight_device *bd) 71 { 72 fb_unregister_client(&bd->fb_notif); 73 } 74 #else 75 static inline int backlight_register_fb(struct backlight_device *bd) 76 { 77 return 0; 78 } 79 80 static inline void backlight_unregister_fb(struct backlight_device *bd) 81 { 82 } 83 #endif /* CONFIG_FB */ 84 85 static void backlight_generate_event(struct backlight_device *bd, 86 enum backlight_update_reason reason) 87 { 88 char *envp[2]; 89 90 switch (reason) { 91 case BACKLIGHT_UPDATE_SYSFS: 92 envp[0] = "SOURCE=sysfs"; 93 break; 94 case BACKLIGHT_UPDATE_HOTKEY: 95 envp[0] = "SOURCE=hotkey"; 96 break; 97 default: 98 envp[0] = "SOURCE=unknown"; 99 break; 100 } 101 envp[1] = NULL; 102 kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp); 103 sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness"); 104 } 105 106 static ssize_t bl_power_show(struct device *dev, struct device_attribute *attr, 107 char *buf) 108 { 109 struct backlight_device *bd = to_backlight_device(dev); 110 111 return sprintf(buf, "%d\n", bd->props.power); 112 } 113 114 static ssize_t bl_power_store(struct device *dev, struct device_attribute *attr, 115 const char *buf, size_t count) 116 { 117 int rc; 118 struct backlight_device *bd = to_backlight_device(dev); 119 unsigned long power; 120 121 rc = kstrtoul(buf, 0, &power); 122 if (rc) 123 return rc; 124 125 rc = -ENXIO; 126 mutex_lock(&bd->ops_lock); 127 if (bd->ops) { 128 pr_debug("set power to %lu\n", power); 129 if (bd->props.power != power) { 130 bd->props.power = power; 131 backlight_update_status(bd); 132 } 133 rc = count; 134 } 135 mutex_unlock(&bd->ops_lock); 136 137 return rc; 138 } 139 static DEVICE_ATTR_RW(bl_power); 140 141 static ssize_t brightness_show(struct device *dev, 142 struct device_attribute *attr, char *buf) 143 { 144 struct backlight_device *bd = to_backlight_device(dev); 145 146 return sprintf(buf, "%d\n", bd->props.brightness); 147 } 148 149 static ssize_t brightness_store(struct device *dev, 150 struct device_attribute *attr, const char *buf, size_t count) 151 { 152 int rc; 153 struct backlight_device *bd = to_backlight_device(dev); 154 unsigned long brightness; 155 156 rc = kstrtoul(buf, 0, &brightness); 157 if (rc) 158 return rc; 159 160 rc = -ENXIO; 161 162 mutex_lock(&bd->ops_lock); 163 if (bd->ops) { 164 if (brightness > bd->props.max_brightness) 165 rc = -EINVAL; 166 else { 167 pr_debug("set brightness to %lu\n", brightness); 168 bd->props.brightness = brightness; 169 backlight_update_status(bd); 170 rc = count; 171 } 172 } 173 mutex_unlock(&bd->ops_lock); 174 175 backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS); 176 177 return rc; 178 } 179 static DEVICE_ATTR_RW(brightness); 180 181 static ssize_t type_show(struct device *dev, struct device_attribute *attr, 182 char *buf) 183 { 184 struct backlight_device *bd = to_backlight_device(dev); 185 186 return sprintf(buf, "%s\n", backlight_types[bd->props.type]); 187 } 188 static DEVICE_ATTR_RO(type); 189 190 static ssize_t max_brightness_show(struct device *dev, 191 struct device_attribute *attr, char *buf) 192 { 193 struct backlight_device *bd = to_backlight_device(dev); 194 195 return sprintf(buf, "%d\n", bd->props.max_brightness); 196 } 197 static DEVICE_ATTR_RO(max_brightness); 198 199 static ssize_t actual_brightness_show(struct device *dev, 200 struct device_attribute *attr, char *buf) 201 { 202 int rc = -ENXIO; 203 struct backlight_device *bd = to_backlight_device(dev); 204 205 mutex_lock(&bd->ops_lock); 206 if (bd->ops && bd->ops->get_brightness) 207 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd)); 208 mutex_unlock(&bd->ops_lock); 209 210 return rc; 211 } 212 static DEVICE_ATTR_RO(actual_brightness); 213 214 static struct class *backlight_class; 215 216 #ifdef CONFIG_PM_SLEEP 217 static int backlight_suspend(struct device *dev) 218 { 219 struct backlight_device *bd = to_backlight_device(dev); 220 221 mutex_lock(&bd->ops_lock); 222 if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) { 223 bd->props.state |= BL_CORE_SUSPENDED; 224 backlight_update_status(bd); 225 } 226 mutex_unlock(&bd->ops_lock); 227 228 return 0; 229 } 230 231 static int backlight_resume(struct device *dev) 232 { 233 struct backlight_device *bd = to_backlight_device(dev); 234 235 mutex_lock(&bd->ops_lock); 236 if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) { 237 bd->props.state &= ~BL_CORE_SUSPENDED; 238 backlight_update_status(bd); 239 } 240 mutex_unlock(&bd->ops_lock); 241 242 return 0; 243 } 244 #endif 245 246 static SIMPLE_DEV_PM_OPS(backlight_class_dev_pm_ops, backlight_suspend, 247 backlight_resume); 248 249 static void bl_device_release(struct device *dev) 250 { 251 struct backlight_device *bd = to_backlight_device(dev); 252 kfree(bd); 253 } 254 255 static struct attribute *bl_device_attrs[] = { 256 &dev_attr_bl_power.attr, 257 &dev_attr_brightness.attr, 258 &dev_attr_actual_brightness.attr, 259 &dev_attr_max_brightness.attr, 260 &dev_attr_type.attr, 261 NULL, 262 }; 263 ATTRIBUTE_GROUPS(bl_device); 264 265 /** 266 * backlight_force_update - tell the backlight subsystem that hardware state 267 * has changed 268 * @bd: the backlight device to update 269 * 270 * Updates the internal state of the backlight in response to a hardware event, 271 * and generate a uevent to notify userspace 272 */ 273 void backlight_force_update(struct backlight_device *bd, 274 enum backlight_update_reason reason) 275 { 276 mutex_lock(&bd->ops_lock); 277 if (bd->ops && bd->ops->get_brightness) 278 bd->props.brightness = bd->ops->get_brightness(bd); 279 mutex_unlock(&bd->ops_lock); 280 backlight_generate_event(bd, reason); 281 } 282 EXPORT_SYMBOL(backlight_force_update); 283 284 /** 285 * backlight_device_register - create and register a new object of 286 * backlight_device class. 287 * @name: the name of the new object(must be the same as the name of the 288 * respective framebuffer device). 289 * @parent: a pointer to the parent device 290 * @devdata: an optional pointer to be stored for private driver use. The 291 * methods may retrieve it by using bl_get_data(bd). 292 * @ops: the backlight operations structure. 293 * 294 * Creates and registers new backlight device. Returns either an 295 * ERR_PTR() or a pointer to the newly allocated device. 296 */ 297 struct backlight_device *backlight_device_register(const char *name, 298 struct device *parent, void *devdata, const struct backlight_ops *ops, 299 const struct backlight_properties *props) 300 { 301 struct backlight_device *new_bd; 302 int rc; 303 304 pr_debug("backlight_device_register: name=%s\n", name); 305 306 new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL); 307 if (!new_bd) 308 return ERR_PTR(-ENOMEM); 309 310 mutex_init(&new_bd->update_lock); 311 mutex_init(&new_bd->ops_lock); 312 313 new_bd->dev.class = backlight_class; 314 new_bd->dev.parent = parent; 315 new_bd->dev.release = bl_device_release; 316 dev_set_name(&new_bd->dev, "%s", name); 317 dev_set_drvdata(&new_bd->dev, devdata); 318 319 /* Set default properties */ 320 if (props) { 321 memcpy(&new_bd->props, props, 322 sizeof(struct backlight_properties)); 323 if (props->type <= 0 || props->type >= BACKLIGHT_TYPE_MAX) { 324 WARN(1, "%s: invalid backlight type", name); 325 new_bd->props.type = BACKLIGHT_RAW; 326 } 327 } else { 328 new_bd->props.type = BACKLIGHT_RAW; 329 } 330 331 rc = device_register(&new_bd->dev); 332 if (rc) { 333 kfree(new_bd); 334 return ERR_PTR(rc); 335 } 336 337 rc = backlight_register_fb(new_bd); 338 if (rc) { 339 device_unregister(&new_bd->dev); 340 return ERR_PTR(rc); 341 } 342 343 new_bd->ops = ops; 344 345 #ifdef CONFIG_PMAC_BACKLIGHT 346 mutex_lock(&pmac_backlight_mutex); 347 if (!pmac_backlight) 348 pmac_backlight = new_bd; 349 mutex_unlock(&pmac_backlight_mutex); 350 #endif 351 352 return new_bd; 353 } 354 EXPORT_SYMBOL(backlight_device_register); 355 356 /** 357 * backlight_device_unregister - unregisters a backlight device object. 358 * @bd: the backlight device object to be unregistered and freed. 359 * 360 * Unregisters a previously registered via backlight_device_register object. 361 */ 362 void backlight_device_unregister(struct backlight_device *bd) 363 { 364 if (!bd) 365 return; 366 367 #ifdef CONFIG_PMAC_BACKLIGHT 368 mutex_lock(&pmac_backlight_mutex); 369 if (pmac_backlight == bd) 370 pmac_backlight = NULL; 371 mutex_unlock(&pmac_backlight_mutex); 372 #endif 373 mutex_lock(&bd->ops_lock); 374 bd->ops = NULL; 375 mutex_unlock(&bd->ops_lock); 376 377 backlight_unregister_fb(bd); 378 device_unregister(&bd->dev); 379 } 380 EXPORT_SYMBOL(backlight_device_unregister); 381 382 static void devm_backlight_device_release(struct device *dev, void *res) 383 { 384 struct backlight_device *backlight = *(struct backlight_device **)res; 385 386 backlight_device_unregister(backlight); 387 } 388 389 static int devm_backlight_device_match(struct device *dev, void *res, 390 void *data) 391 { 392 struct backlight_device **r = res; 393 394 return *r == data; 395 } 396 397 /** 398 * devm_backlight_device_register - resource managed backlight_device_register() 399 * @dev: the device to register 400 * @name: the name of the device 401 * @parent: a pointer to the parent device 402 * @devdata: an optional pointer to be stored for private driver use 403 * @ops: the backlight operations structure 404 * @props: the backlight properties 405 * 406 * @return a struct backlight on success, or an ERR_PTR on error 407 * 408 * Managed backlight_device_register(). The backlight_device returned 409 * from this function are automatically freed on driver detach. 410 * See backlight_device_register() for more information. 411 */ 412 struct backlight_device *devm_backlight_device_register(struct device *dev, 413 const char *name, struct device *parent, void *devdata, 414 const struct backlight_ops *ops, 415 const struct backlight_properties *props) 416 { 417 struct backlight_device **ptr, *backlight; 418 419 ptr = devres_alloc(devm_backlight_device_release, sizeof(*ptr), 420 GFP_KERNEL); 421 if (!ptr) 422 return ERR_PTR(-ENOMEM); 423 424 backlight = backlight_device_register(name, parent, devdata, ops, 425 props); 426 if (!IS_ERR(backlight)) { 427 *ptr = backlight; 428 devres_add(dev, ptr); 429 } else { 430 devres_free(ptr); 431 } 432 433 return backlight; 434 } 435 EXPORT_SYMBOL(devm_backlight_device_register); 436 437 /** 438 * devm_backlight_device_unregister - resource managed backlight_device_unregister() 439 * @dev: the device to unregister 440 * @bd: the backlight device to unregister 441 * 442 * Deallocated a backlight allocated with devm_backlight_device_register(). 443 * Normally this function will not need to be called and the resource management 444 * code will ensure that the resource is freed. 445 */ 446 void devm_backlight_device_unregister(struct device *dev, 447 struct backlight_device *bd) 448 { 449 int rc; 450 451 rc = devres_release(dev, devm_backlight_device_release, 452 devm_backlight_device_match, bd); 453 WARN_ON(rc); 454 } 455 EXPORT_SYMBOL(devm_backlight_device_unregister); 456 457 #ifdef CONFIG_OF 458 static int of_parent_match(struct device *dev, const void *data) 459 { 460 return dev->parent && dev->parent->of_node == data; 461 } 462 463 /** 464 * of_find_backlight_by_node() - find backlight device by device-tree node 465 * @node: device-tree node of the backlight device 466 * 467 * Returns a pointer to the backlight device corresponding to the given DT 468 * node or NULL if no such backlight device exists or if the device hasn't 469 * been probed yet. 470 * 471 * This function obtains a reference on the backlight device and it is the 472 * caller's responsibility to drop the reference by calling put_device() on 473 * the backlight device's .dev field. 474 */ 475 struct backlight_device *of_find_backlight_by_node(struct device_node *node) 476 { 477 struct device *dev; 478 479 dev = class_find_device(backlight_class, NULL, node, of_parent_match); 480 481 return dev ? to_backlight_device(dev) : NULL; 482 } 483 EXPORT_SYMBOL(of_find_backlight_by_node); 484 #endif 485 486 static void __exit backlight_class_exit(void) 487 { 488 class_destroy(backlight_class); 489 } 490 491 static int __init backlight_class_init(void) 492 { 493 backlight_class = class_create(THIS_MODULE, "backlight"); 494 if (IS_ERR(backlight_class)) { 495 pr_warn("Unable to create backlight class; errno = %ld\n", 496 PTR_ERR(backlight_class)); 497 return PTR_ERR(backlight_class); 498 } 499 500 backlight_class->dev_groups = bl_device_groups; 501 backlight_class->pm = &backlight_class_dev_pm_ops; 502 return 0; 503 } 504 505 /* 506 * if this is compiled into the kernel, we need to ensure that the 507 * class is registered before users of the class try to register lcd's 508 */ 509 postcore_initcall(backlight_class_init); 510 module_exit(backlight_class_exit); 511 512 MODULE_LICENSE("GPL"); 513 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 514 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction"); 515