1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * LED Class Core 4 * 5 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu> 6 * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com> 7 */ 8 9 #include <linux/ctype.h> 10 #include <linux/device.h> 11 #include <linux/err.h> 12 #include <linux/init.h> 13 #include <linux/kernel.h> 14 #include <linux/leds.h> 15 #include <linux/list.h> 16 #include <linux/module.h> 17 #include <linux/property.h> 18 #include <linux/slab.h> 19 #include <linux/spinlock.h> 20 #include <linux/timer.h> 21 #include <uapi/linux/uleds.h> 22 #include <linux/of.h> 23 #include "leds.h" 24 25 static struct class *leds_class; 26 27 static ssize_t brightness_show(struct device *dev, 28 struct device_attribute *attr, char *buf) 29 { 30 struct led_classdev *led_cdev = dev_get_drvdata(dev); 31 32 /* no lock needed for this */ 33 led_update_brightness(led_cdev); 34 35 return sprintf(buf, "%u\n", led_cdev->brightness); 36 } 37 38 static ssize_t brightness_store(struct device *dev, 39 struct device_attribute *attr, const char *buf, size_t size) 40 { 41 struct led_classdev *led_cdev = dev_get_drvdata(dev); 42 unsigned long state; 43 ssize_t ret; 44 45 mutex_lock(&led_cdev->led_access); 46 47 if (led_sysfs_is_disabled(led_cdev)) { 48 ret = -EBUSY; 49 goto unlock; 50 } 51 52 ret = kstrtoul(buf, 10, &state); 53 if (ret) 54 goto unlock; 55 56 if (state == LED_OFF) 57 led_trigger_remove(led_cdev); 58 led_set_brightness(led_cdev, state); 59 flush_work(&led_cdev->set_brightness_work); 60 61 ret = size; 62 unlock: 63 mutex_unlock(&led_cdev->led_access); 64 return ret; 65 } 66 static DEVICE_ATTR_RW(brightness); 67 68 static ssize_t max_brightness_show(struct device *dev, 69 struct device_attribute *attr, char *buf) 70 { 71 struct led_classdev *led_cdev = dev_get_drvdata(dev); 72 73 return sprintf(buf, "%u\n", led_cdev->max_brightness); 74 } 75 static DEVICE_ATTR_RO(max_brightness); 76 77 #ifdef CONFIG_LEDS_TRIGGERS 78 static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0); 79 static struct bin_attribute *led_trigger_bin_attrs[] = { 80 &bin_attr_trigger, 81 NULL, 82 }; 83 static const struct attribute_group led_trigger_group = { 84 .bin_attrs = led_trigger_bin_attrs, 85 }; 86 #endif 87 88 static struct attribute *led_class_attrs[] = { 89 &dev_attr_brightness.attr, 90 &dev_attr_max_brightness.attr, 91 NULL, 92 }; 93 94 static const struct attribute_group led_group = { 95 .attrs = led_class_attrs, 96 }; 97 98 static const struct attribute_group *led_groups[] = { 99 &led_group, 100 #ifdef CONFIG_LEDS_TRIGGERS 101 &led_trigger_group, 102 #endif 103 NULL, 104 }; 105 106 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED 107 static ssize_t brightness_hw_changed_show(struct device *dev, 108 struct device_attribute *attr, char *buf) 109 { 110 struct led_classdev *led_cdev = dev_get_drvdata(dev); 111 112 if (led_cdev->brightness_hw_changed == -1) 113 return -ENODATA; 114 115 return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed); 116 } 117 118 static DEVICE_ATTR_RO(brightness_hw_changed); 119 120 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev) 121 { 122 struct device *dev = led_cdev->dev; 123 int ret; 124 125 ret = device_create_file(dev, &dev_attr_brightness_hw_changed); 126 if (ret) { 127 dev_err(dev, "Error creating brightness_hw_changed\n"); 128 return ret; 129 } 130 131 led_cdev->brightness_hw_changed_kn = 132 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed"); 133 if (!led_cdev->brightness_hw_changed_kn) { 134 dev_err(dev, "Error getting brightness_hw_changed kn\n"); 135 device_remove_file(dev, &dev_attr_brightness_hw_changed); 136 return -ENXIO; 137 } 138 139 return 0; 140 } 141 142 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev) 143 { 144 sysfs_put(led_cdev->brightness_hw_changed_kn); 145 device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed); 146 } 147 148 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int brightness) 149 { 150 if (WARN_ON(!led_cdev->brightness_hw_changed_kn)) 151 return; 152 153 led_cdev->brightness_hw_changed = brightness; 154 sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn); 155 } 156 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed); 157 #else 158 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev) 159 { 160 return 0; 161 } 162 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev) 163 { 164 } 165 #endif 166 167 /** 168 * led_classdev_suspend - suspend an led_classdev. 169 * @led_cdev: the led_classdev to suspend. 170 */ 171 void led_classdev_suspend(struct led_classdev *led_cdev) 172 { 173 led_cdev->flags |= LED_SUSPENDED; 174 led_set_brightness_nopm(led_cdev, 0); 175 flush_work(&led_cdev->set_brightness_work); 176 } 177 EXPORT_SYMBOL_GPL(led_classdev_suspend); 178 179 /** 180 * led_classdev_resume - resume an led_classdev. 181 * @led_cdev: the led_classdev to resume. 182 */ 183 void led_classdev_resume(struct led_classdev *led_cdev) 184 { 185 led_set_brightness_nopm(led_cdev, led_cdev->brightness); 186 187 if (led_cdev->flash_resume) 188 led_cdev->flash_resume(led_cdev); 189 190 led_cdev->flags &= ~LED_SUSPENDED; 191 } 192 EXPORT_SYMBOL_GPL(led_classdev_resume); 193 194 #ifdef CONFIG_PM_SLEEP 195 static int led_suspend(struct device *dev) 196 { 197 struct led_classdev *led_cdev = dev_get_drvdata(dev); 198 199 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 200 led_classdev_suspend(led_cdev); 201 202 return 0; 203 } 204 205 static int led_resume(struct device *dev) 206 { 207 struct led_classdev *led_cdev = dev_get_drvdata(dev); 208 209 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 210 led_classdev_resume(led_cdev); 211 212 return 0; 213 } 214 #endif 215 216 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume); 217 218 /** 219 * of_led_get() - request a LED device via the LED framework 220 * @np: device node to get the LED device from 221 * @index: the index of the LED 222 * 223 * Returns the LED device parsed from the phandle specified in the "leds" 224 * property of a device tree node or a negative error-code on failure. 225 */ 226 struct led_classdev *of_led_get(struct device_node *np, int index) 227 { 228 struct device *led_dev; 229 struct led_classdev *led_cdev; 230 struct device_node *led_node; 231 232 led_node = of_parse_phandle(np, "leds", index); 233 if (!led_node) 234 return ERR_PTR(-ENOENT); 235 236 led_dev = class_find_device_by_of_node(leds_class, led_node); 237 of_node_put(led_node); 238 239 if (!led_dev) 240 return ERR_PTR(-EPROBE_DEFER); 241 242 led_cdev = dev_get_drvdata(led_dev); 243 244 if (!try_module_get(led_cdev->dev->parent->driver->owner)) 245 return ERR_PTR(-ENODEV); 246 247 return led_cdev; 248 } 249 EXPORT_SYMBOL_GPL(of_led_get); 250 251 /** 252 * led_put() - release a LED device 253 * @led_cdev: LED device 254 */ 255 void led_put(struct led_classdev *led_cdev) 256 { 257 module_put(led_cdev->dev->parent->driver->owner); 258 } 259 EXPORT_SYMBOL_GPL(led_put); 260 261 static void devm_led_release(struct device *dev, void *res) 262 { 263 struct led_classdev **p = res; 264 265 led_put(*p); 266 } 267 268 /** 269 * devm_of_led_get - Resource-managed request of a LED device 270 * @dev: LED consumer 271 * @index: index of the LED to obtain in the consumer 272 * 273 * The device node of the device is parse to find the request LED device. 274 * The LED device returned from this function is automatically released 275 * on driver detach. 276 * 277 * @return a pointer to a LED device or ERR_PTR(errno) on failure. 278 */ 279 struct led_classdev *__must_check devm_of_led_get(struct device *dev, 280 int index) 281 { 282 struct led_classdev *led; 283 struct led_classdev **dr; 284 285 if (!dev) 286 return ERR_PTR(-EINVAL); 287 288 led = of_led_get(dev->of_node, index); 289 if (IS_ERR(led)) 290 return led; 291 292 dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), 293 GFP_KERNEL); 294 if (!dr) { 295 led_put(led); 296 return ERR_PTR(-ENOMEM); 297 } 298 299 *dr = led; 300 devres_add(dev, dr); 301 302 return led; 303 } 304 EXPORT_SYMBOL_GPL(devm_of_led_get); 305 306 static int led_classdev_next_name(const char *init_name, char *name, 307 size_t len) 308 { 309 unsigned int i = 0; 310 int ret = 0; 311 struct device *dev; 312 313 strlcpy(name, init_name, len); 314 315 while ((ret < len) && 316 (dev = class_find_device_by_name(leds_class, name))) { 317 put_device(dev); 318 ret = snprintf(name, len, "%s_%u", init_name, ++i); 319 } 320 321 if (ret >= len) 322 return -ENOMEM; 323 324 return i; 325 } 326 327 /** 328 * led_classdev_register_ext - register a new object of led_classdev class 329 * with init data. 330 * 331 * @parent: parent of LED device 332 * @led_cdev: the led_classdev structure for this device. 333 * @init_data: LED class device initialization data 334 */ 335 int led_classdev_register_ext(struct device *parent, 336 struct led_classdev *led_cdev, 337 struct led_init_data *init_data) 338 { 339 char composed_name[LED_MAX_NAME_SIZE]; 340 char final_name[LED_MAX_NAME_SIZE]; 341 const char *proposed_name = composed_name; 342 int ret; 343 344 if (init_data) { 345 if (init_data->devname_mandatory && !init_data->devicename) { 346 dev_err(parent, "Mandatory device name is missing"); 347 return -EINVAL; 348 } 349 ret = led_compose_name(parent, init_data, composed_name); 350 if (ret < 0) 351 return ret; 352 353 if (init_data->fwnode) { 354 fwnode_property_read_string(init_data->fwnode, 355 "linux,default-trigger", 356 &led_cdev->default_trigger); 357 358 if (fwnode_property_present(init_data->fwnode, 359 "retain-state-shutdown")) 360 led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN; 361 } 362 } else { 363 proposed_name = led_cdev->name; 364 } 365 366 ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name)); 367 if (ret < 0) 368 return ret; 369 370 mutex_init(&led_cdev->led_access); 371 mutex_lock(&led_cdev->led_access); 372 led_cdev->dev = device_create_with_groups(leds_class, parent, 0, 373 led_cdev, led_cdev->groups, "%s", final_name); 374 if (IS_ERR(led_cdev->dev)) { 375 mutex_unlock(&led_cdev->led_access); 376 return PTR_ERR(led_cdev->dev); 377 } 378 if (init_data && init_data->fwnode) { 379 led_cdev->dev->fwnode = init_data->fwnode; 380 led_cdev->dev->of_node = to_of_node(init_data->fwnode); 381 } 382 383 if (ret) 384 dev_warn(parent, "Led %s renamed to %s due to name collision", 385 proposed_name, dev_name(led_cdev->dev)); 386 387 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) { 388 ret = led_add_brightness_hw_changed(led_cdev); 389 if (ret) { 390 device_unregister(led_cdev->dev); 391 led_cdev->dev = NULL; 392 mutex_unlock(&led_cdev->led_access); 393 return ret; 394 } 395 } 396 397 led_cdev->work_flags = 0; 398 #ifdef CONFIG_LEDS_TRIGGERS 399 init_rwsem(&led_cdev->trigger_lock); 400 #endif 401 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED 402 led_cdev->brightness_hw_changed = -1; 403 #endif 404 /* add to the list of leds */ 405 down_write(&leds_list_lock); 406 list_add_tail(&led_cdev->node, &leds_list); 407 up_write(&leds_list_lock); 408 409 if (!led_cdev->max_brightness) 410 led_cdev->max_brightness = LED_FULL; 411 412 led_update_brightness(led_cdev); 413 414 led_init_core(led_cdev); 415 416 #ifdef CONFIG_LEDS_TRIGGERS 417 led_trigger_set_default(led_cdev); 418 #endif 419 420 mutex_unlock(&led_cdev->led_access); 421 422 dev_dbg(parent, "Registered led device: %s\n", 423 led_cdev->name); 424 425 return 0; 426 } 427 EXPORT_SYMBOL_GPL(led_classdev_register_ext); 428 429 /** 430 * led_classdev_unregister - unregisters a object of led_properties class. 431 * @led_cdev: the led device to unregister 432 * 433 * Unregisters a previously registered via led_classdev_register object. 434 */ 435 void led_classdev_unregister(struct led_classdev *led_cdev) 436 { 437 if (IS_ERR_OR_NULL(led_cdev->dev)) 438 return; 439 440 #ifdef CONFIG_LEDS_TRIGGERS 441 down_write(&led_cdev->trigger_lock); 442 if (led_cdev->trigger) 443 led_trigger_set(led_cdev, NULL); 444 up_write(&led_cdev->trigger_lock); 445 #endif 446 447 led_cdev->flags |= LED_UNREGISTERING; 448 449 /* Stop blinking */ 450 led_stop_software_blink(led_cdev); 451 452 if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN)) 453 led_set_brightness(led_cdev, LED_OFF); 454 455 flush_work(&led_cdev->set_brightness_work); 456 457 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) 458 led_remove_brightness_hw_changed(led_cdev); 459 460 device_unregister(led_cdev->dev); 461 462 down_write(&leds_list_lock); 463 list_del(&led_cdev->node); 464 up_write(&leds_list_lock); 465 466 mutex_destroy(&led_cdev->led_access); 467 } 468 EXPORT_SYMBOL_GPL(led_classdev_unregister); 469 470 static void devm_led_classdev_release(struct device *dev, void *res) 471 { 472 led_classdev_unregister(*(struct led_classdev **)res); 473 } 474 475 /** 476 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext() 477 * 478 * @parent: parent of LED device 479 * @led_cdev: the led_classdev structure for this device. 480 * @init_data: LED class device initialization data 481 */ 482 int devm_led_classdev_register_ext(struct device *parent, 483 struct led_classdev *led_cdev, 484 struct led_init_data *init_data) 485 { 486 struct led_classdev **dr; 487 int rc; 488 489 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL); 490 if (!dr) 491 return -ENOMEM; 492 493 rc = led_classdev_register_ext(parent, led_cdev, init_data); 494 if (rc) { 495 devres_free(dr); 496 return rc; 497 } 498 499 *dr = led_cdev; 500 devres_add(parent, dr); 501 502 return 0; 503 } 504 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext); 505 506 static int devm_led_classdev_match(struct device *dev, void *res, void *data) 507 { 508 struct led_classdev **p = res; 509 510 if (WARN_ON(!p || !*p)) 511 return 0; 512 513 return *p == data; 514 } 515 516 /** 517 * devm_led_classdev_unregister() - resource managed led_classdev_unregister() 518 * @dev: The device to unregister. 519 * @led_cdev: the led_classdev structure for this device. 520 */ 521 void devm_led_classdev_unregister(struct device *dev, 522 struct led_classdev *led_cdev) 523 { 524 WARN_ON(devres_release(dev, 525 devm_led_classdev_release, 526 devm_led_classdev_match, led_cdev)); 527 } 528 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister); 529 530 static int __init leds_init(void) 531 { 532 leds_class = class_create(THIS_MODULE, "leds"); 533 if (IS_ERR(leds_class)) 534 return PTR_ERR(leds_class); 535 leds_class->pm = &leds_class_dev_pm_ops; 536 leds_class->dev_groups = led_groups; 537 return 0; 538 } 539 540 static void __exit leds_exit(void) 541 { 542 class_destroy(leds_class); 543 } 544 545 subsys_initcall(leds_init); 546 module_exit(leds_exit); 547 548 MODULE_AUTHOR("John Lenz, Richard Purdie"); 549 MODULE_LICENSE("GPL"); 550 MODULE_DESCRIPTION("LED Class Interface"); 551