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 struct list_head backlight_dev_list; 25 static struct mutex backlight_dev_list_mutex; 26 27 static const char *const backlight_types[] = { 28 [BACKLIGHT_RAW] = "raw", 29 [BACKLIGHT_PLATFORM] = "platform", 30 [BACKLIGHT_FIRMWARE] = "firmware", 31 }; 32 33 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ 34 defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)) 35 /* This callback gets called when something important happens inside a 36 * framebuffer driver. We're looking if that important event is blanking, 37 * and if it is, we're switching backlight power as well ... 38 */ 39 static int fb_notifier_callback(struct notifier_block *self, 40 unsigned long event, void *data) 41 { 42 struct backlight_device *bd; 43 struct fb_event *evdata = data; 44 45 /* If we aren't interested in this event, skip it immediately ... */ 46 if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK) 47 return 0; 48 49 bd = container_of(self, struct backlight_device, fb_notif); 50 mutex_lock(&bd->ops_lock); 51 if (bd->ops) 52 if (!bd->ops->check_fb || 53 bd->ops->check_fb(bd, evdata->info)) { 54 bd->props.fb_blank = *(int *)evdata->data; 55 if (bd->props.fb_blank == FB_BLANK_UNBLANK) 56 bd->props.state &= ~BL_CORE_FBBLANK; 57 else 58 bd->props.state |= BL_CORE_FBBLANK; 59 backlight_update_status(bd); 60 } 61 mutex_unlock(&bd->ops_lock); 62 return 0; 63 } 64 65 static int backlight_register_fb(struct backlight_device *bd) 66 { 67 memset(&bd->fb_notif, 0, sizeof(bd->fb_notif)); 68 bd->fb_notif.notifier_call = fb_notifier_callback; 69 70 return fb_register_client(&bd->fb_notif); 71 } 72 73 static void backlight_unregister_fb(struct backlight_device *bd) 74 { 75 fb_unregister_client(&bd->fb_notif); 76 } 77 #else 78 static inline int backlight_register_fb(struct backlight_device *bd) 79 { 80 return 0; 81 } 82 83 static inline void backlight_unregister_fb(struct backlight_device *bd) 84 { 85 } 86 #endif /* CONFIG_FB */ 87 88 static void backlight_generate_event(struct backlight_device *bd, 89 enum backlight_update_reason reason) 90 { 91 char *envp[2]; 92 93 switch (reason) { 94 case BACKLIGHT_UPDATE_SYSFS: 95 envp[0] = "SOURCE=sysfs"; 96 break; 97 case BACKLIGHT_UPDATE_HOTKEY: 98 envp[0] = "SOURCE=hotkey"; 99 break; 100 default: 101 envp[0] = "SOURCE=unknown"; 102 break; 103 } 104 envp[1] = NULL; 105 kobject_uevent_env(&bd->dev.kobj, KOBJ_CHANGE, envp); 106 sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness"); 107 } 108 109 static ssize_t bl_power_show(struct device *dev, struct device_attribute *attr, 110 char *buf) 111 { 112 struct backlight_device *bd = to_backlight_device(dev); 113 114 return sprintf(buf, "%d\n", bd->props.power); 115 } 116 117 static ssize_t bl_power_store(struct device *dev, struct device_attribute *attr, 118 const char *buf, size_t count) 119 { 120 int rc; 121 struct backlight_device *bd = to_backlight_device(dev); 122 unsigned long power; 123 124 rc = kstrtoul(buf, 0, &power); 125 if (rc) 126 return rc; 127 128 rc = -ENXIO; 129 mutex_lock(&bd->ops_lock); 130 if (bd->ops) { 131 pr_debug("set power to %lu\n", power); 132 if (bd->props.power != power) { 133 bd->props.power = power; 134 backlight_update_status(bd); 135 } 136 rc = count; 137 } 138 mutex_unlock(&bd->ops_lock); 139 140 return rc; 141 } 142 static DEVICE_ATTR_RW(bl_power); 143 144 static ssize_t brightness_show(struct device *dev, 145 struct device_attribute *attr, char *buf) 146 { 147 struct backlight_device *bd = to_backlight_device(dev); 148 149 return sprintf(buf, "%d\n", bd->props.brightness); 150 } 151 152 static ssize_t brightness_store(struct device *dev, 153 struct device_attribute *attr, const char *buf, size_t count) 154 { 155 int rc; 156 struct backlight_device *bd = to_backlight_device(dev); 157 unsigned long brightness; 158 159 rc = kstrtoul(buf, 0, &brightness); 160 if (rc) 161 return rc; 162 163 rc = -ENXIO; 164 165 mutex_lock(&bd->ops_lock); 166 if (bd->ops) { 167 if (brightness > bd->props.max_brightness) 168 rc = -EINVAL; 169 else { 170 pr_debug("set brightness to %lu\n", brightness); 171 bd->props.brightness = brightness; 172 backlight_update_status(bd); 173 rc = count; 174 } 175 } 176 mutex_unlock(&bd->ops_lock); 177 178 backlight_generate_event(bd, BACKLIGHT_UPDATE_SYSFS); 179 180 return rc; 181 } 182 static DEVICE_ATTR_RW(brightness); 183 184 static ssize_t type_show(struct device *dev, struct device_attribute *attr, 185 char *buf) 186 { 187 struct backlight_device *bd = to_backlight_device(dev); 188 189 return sprintf(buf, "%s\n", backlight_types[bd->props.type]); 190 } 191 static DEVICE_ATTR_RO(type); 192 193 static ssize_t max_brightness_show(struct device *dev, 194 struct device_attribute *attr, char *buf) 195 { 196 struct backlight_device *bd = to_backlight_device(dev); 197 198 return sprintf(buf, "%d\n", bd->props.max_brightness); 199 } 200 static DEVICE_ATTR_RO(max_brightness); 201 202 static ssize_t actual_brightness_show(struct device *dev, 203 struct device_attribute *attr, char *buf) 204 { 205 int rc = -ENXIO; 206 struct backlight_device *bd = to_backlight_device(dev); 207 208 mutex_lock(&bd->ops_lock); 209 if (bd->ops && bd->ops->get_brightness) 210 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd)); 211 mutex_unlock(&bd->ops_lock); 212 213 return rc; 214 } 215 static DEVICE_ATTR_RO(actual_brightness); 216 217 static struct class *backlight_class; 218 219 #ifdef CONFIG_PM_SLEEP 220 static int backlight_suspend(struct device *dev) 221 { 222 struct backlight_device *bd = to_backlight_device(dev); 223 224 mutex_lock(&bd->ops_lock); 225 if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) { 226 bd->props.state |= BL_CORE_SUSPENDED; 227 backlight_update_status(bd); 228 } 229 mutex_unlock(&bd->ops_lock); 230 231 return 0; 232 } 233 234 static int backlight_resume(struct device *dev) 235 { 236 struct backlight_device *bd = to_backlight_device(dev); 237 238 mutex_lock(&bd->ops_lock); 239 if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) { 240 bd->props.state &= ~BL_CORE_SUSPENDED; 241 backlight_update_status(bd); 242 } 243 mutex_unlock(&bd->ops_lock); 244 245 return 0; 246 } 247 #endif 248 249 static SIMPLE_DEV_PM_OPS(backlight_class_dev_pm_ops, backlight_suspend, 250 backlight_resume); 251 252 static void bl_device_release(struct device *dev) 253 { 254 struct backlight_device *bd = to_backlight_device(dev); 255 kfree(bd); 256 } 257 258 static struct attribute *bl_device_attrs[] = { 259 &dev_attr_bl_power.attr, 260 &dev_attr_brightness.attr, 261 &dev_attr_actual_brightness.attr, 262 &dev_attr_max_brightness.attr, 263 &dev_attr_type.attr, 264 NULL, 265 }; 266 ATTRIBUTE_GROUPS(bl_device); 267 268 /** 269 * backlight_force_update - tell the backlight subsystem that hardware state 270 * has changed 271 * @bd: the backlight device to update 272 * 273 * Updates the internal state of the backlight in response to a hardware event, 274 * and generate a uevent to notify userspace 275 */ 276 void backlight_force_update(struct backlight_device *bd, 277 enum backlight_update_reason reason) 278 { 279 mutex_lock(&bd->ops_lock); 280 if (bd->ops && bd->ops->get_brightness) 281 bd->props.brightness = bd->ops->get_brightness(bd); 282 mutex_unlock(&bd->ops_lock); 283 backlight_generate_event(bd, reason); 284 } 285 EXPORT_SYMBOL(backlight_force_update); 286 287 /** 288 * backlight_device_register - create and register a new object of 289 * backlight_device class. 290 * @name: the name of the new object(must be the same as the name of the 291 * respective framebuffer device). 292 * @parent: a pointer to the parent device 293 * @devdata: an optional pointer to be stored for private driver use. The 294 * methods may retrieve it by using bl_get_data(bd). 295 * @ops: the backlight operations structure. 296 * 297 * Creates and registers new backlight device. Returns either an 298 * ERR_PTR() or a pointer to the newly allocated device. 299 */ 300 struct backlight_device *backlight_device_register(const char *name, 301 struct device *parent, void *devdata, const struct backlight_ops *ops, 302 const struct backlight_properties *props) 303 { 304 struct backlight_device *new_bd; 305 int rc; 306 307 pr_debug("backlight_device_register: name=%s\n", name); 308 309 new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL); 310 if (!new_bd) 311 return ERR_PTR(-ENOMEM); 312 313 mutex_init(&new_bd->update_lock); 314 mutex_init(&new_bd->ops_lock); 315 316 new_bd->dev.class = backlight_class; 317 new_bd->dev.parent = parent; 318 new_bd->dev.release = bl_device_release; 319 dev_set_name(&new_bd->dev, "%s", name); 320 dev_set_drvdata(&new_bd->dev, devdata); 321 322 /* Set default properties */ 323 if (props) { 324 memcpy(&new_bd->props, props, 325 sizeof(struct backlight_properties)); 326 if (props->type <= 0 || props->type >= BACKLIGHT_TYPE_MAX) { 327 WARN(1, "%s: invalid backlight type", name); 328 new_bd->props.type = BACKLIGHT_RAW; 329 } 330 } else { 331 new_bd->props.type = BACKLIGHT_RAW; 332 } 333 334 rc = device_register(&new_bd->dev); 335 if (rc) { 336 kfree(new_bd); 337 return ERR_PTR(rc); 338 } 339 340 rc = backlight_register_fb(new_bd); 341 if (rc) { 342 device_unregister(&new_bd->dev); 343 return ERR_PTR(rc); 344 } 345 346 new_bd->ops = ops; 347 348 #ifdef CONFIG_PMAC_BACKLIGHT 349 mutex_lock(&pmac_backlight_mutex); 350 if (!pmac_backlight) 351 pmac_backlight = new_bd; 352 mutex_unlock(&pmac_backlight_mutex); 353 #endif 354 355 mutex_lock(&backlight_dev_list_mutex); 356 list_add(&new_bd->entry, &backlight_dev_list); 357 mutex_unlock(&backlight_dev_list_mutex); 358 359 return new_bd; 360 } 361 EXPORT_SYMBOL(backlight_device_register); 362 363 bool backlight_device_registered(enum backlight_type type) 364 { 365 bool found = false; 366 struct backlight_device *bd; 367 368 mutex_lock(&backlight_dev_list_mutex); 369 list_for_each_entry(bd, &backlight_dev_list, entry) { 370 if (bd->props.type == type) { 371 found = true; 372 break; 373 } 374 } 375 mutex_unlock(&backlight_dev_list_mutex); 376 377 return found; 378 } 379 EXPORT_SYMBOL(backlight_device_registered); 380 381 /** 382 * backlight_device_unregister - unregisters a backlight device object. 383 * @bd: the backlight device object to be unregistered and freed. 384 * 385 * Unregisters a previously registered via backlight_device_register object. 386 */ 387 void backlight_device_unregister(struct backlight_device *bd) 388 { 389 if (!bd) 390 return; 391 392 mutex_lock(&backlight_dev_list_mutex); 393 list_del(&bd->entry); 394 mutex_unlock(&backlight_dev_list_mutex); 395 396 #ifdef CONFIG_PMAC_BACKLIGHT 397 mutex_lock(&pmac_backlight_mutex); 398 if (pmac_backlight == bd) 399 pmac_backlight = NULL; 400 mutex_unlock(&pmac_backlight_mutex); 401 #endif 402 mutex_lock(&bd->ops_lock); 403 bd->ops = NULL; 404 mutex_unlock(&bd->ops_lock); 405 406 backlight_unregister_fb(bd); 407 device_unregister(&bd->dev); 408 } 409 EXPORT_SYMBOL(backlight_device_unregister); 410 411 static void devm_backlight_device_release(struct device *dev, void *res) 412 { 413 struct backlight_device *backlight = *(struct backlight_device **)res; 414 415 backlight_device_unregister(backlight); 416 } 417 418 static int devm_backlight_device_match(struct device *dev, void *res, 419 void *data) 420 { 421 struct backlight_device **r = res; 422 423 return *r == data; 424 } 425 426 /** 427 * devm_backlight_device_register - resource managed backlight_device_register() 428 * @dev: the device to register 429 * @name: the name of the device 430 * @parent: a pointer to the parent device 431 * @devdata: an optional pointer to be stored for private driver use 432 * @ops: the backlight operations structure 433 * @props: the backlight properties 434 * 435 * @return a struct backlight on success, or an ERR_PTR on error 436 * 437 * Managed backlight_device_register(). The backlight_device returned 438 * from this function are automatically freed on driver detach. 439 * See backlight_device_register() for more information. 440 */ 441 struct backlight_device *devm_backlight_device_register(struct device *dev, 442 const char *name, struct device *parent, void *devdata, 443 const struct backlight_ops *ops, 444 const struct backlight_properties *props) 445 { 446 struct backlight_device **ptr, *backlight; 447 448 ptr = devres_alloc(devm_backlight_device_release, sizeof(*ptr), 449 GFP_KERNEL); 450 if (!ptr) 451 return ERR_PTR(-ENOMEM); 452 453 backlight = backlight_device_register(name, parent, devdata, ops, 454 props); 455 if (!IS_ERR(backlight)) { 456 *ptr = backlight; 457 devres_add(dev, ptr); 458 } else { 459 devres_free(ptr); 460 } 461 462 return backlight; 463 } 464 EXPORT_SYMBOL(devm_backlight_device_register); 465 466 /** 467 * devm_backlight_device_unregister - resource managed backlight_device_unregister() 468 * @dev: the device to unregister 469 * @bd: the backlight device to unregister 470 * 471 * Deallocated a backlight allocated with devm_backlight_device_register(). 472 * Normally this function will not need to be called and the resource management 473 * code will ensure that the resource is freed. 474 */ 475 void devm_backlight_device_unregister(struct device *dev, 476 struct backlight_device *bd) 477 { 478 int rc; 479 480 rc = devres_release(dev, devm_backlight_device_release, 481 devm_backlight_device_match, bd); 482 WARN_ON(rc); 483 } 484 EXPORT_SYMBOL(devm_backlight_device_unregister); 485 486 #ifdef CONFIG_OF 487 static int of_parent_match(struct device *dev, const void *data) 488 { 489 return dev->parent && dev->parent->of_node == data; 490 } 491 492 /** 493 * of_find_backlight_by_node() - find backlight device by device-tree node 494 * @node: device-tree node of the backlight device 495 * 496 * Returns a pointer to the backlight device corresponding to the given DT 497 * node or NULL if no such backlight device exists or if the device hasn't 498 * been probed yet. 499 * 500 * This function obtains a reference on the backlight device and it is the 501 * caller's responsibility to drop the reference by calling put_device() on 502 * the backlight device's .dev field. 503 */ 504 struct backlight_device *of_find_backlight_by_node(struct device_node *node) 505 { 506 struct device *dev; 507 508 dev = class_find_device(backlight_class, NULL, node, of_parent_match); 509 510 return dev ? to_backlight_device(dev) : NULL; 511 } 512 EXPORT_SYMBOL(of_find_backlight_by_node); 513 #endif 514 515 static void __exit backlight_class_exit(void) 516 { 517 class_destroy(backlight_class); 518 } 519 520 static int __init backlight_class_init(void) 521 { 522 backlight_class = class_create(THIS_MODULE, "backlight"); 523 if (IS_ERR(backlight_class)) { 524 pr_warn("Unable to create backlight class; errno = %ld\n", 525 PTR_ERR(backlight_class)); 526 return PTR_ERR(backlight_class); 527 } 528 529 backlight_class->dev_groups = bl_device_groups; 530 backlight_class->pm = &backlight_class_dev_pm_ops; 531 INIT_LIST_HEAD(&backlight_dev_list); 532 mutex_init(&backlight_dev_list_mutex); 533 return 0; 534 } 535 536 /* 537 * if this is compiled into the kernel, we need to ensure that the 538 * class is registered before users of the class try to register lcd's 539 */ 540 postcore_initcall(backlight_class_init); 541 module_exit(backlight_class_exit); 542 543 MODULE_LICENSE("GPL"); 544 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 545 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction"); 546