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, 149 enum led_brightness brightness) 150 { 151 if (WARN_ON(!led_cdev->brightness_hw_changed_kn)) 152 return; 153 154 led_cdev->brightness_hw_changed = brightness; 155 sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn); 156 } 157 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed); 158 #else 159 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev) 160 { 161 return 0; 162 } 163 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev) 164 { 165 } 166 #endif 167 168 /** 169 * led_classdev_suspend - suspend an led_classdev. 170 * @led_cdev: the led_classdev to suspend. 171 */ 172 void led_classdev_suspend(struct led_classdev *led_cdev) 173 { 174 led_cdev->flags |= LED_SUSPENDED; 175 led_set_brightness_nopm(led_cdev, 0); 176 flush_work(&led_cdev->set_brightness_work); 177 } 178 EXPORT_SYMBOL_GPL(led_classdev_suspend); 179 180 /** 181 * led_classdev_resume - resume an led_classdev. 182 * @led_cdev: the led_classdev to resume. 183 */ 184 void led_classdev_resume(struct led_classdev *led_cdev) 185 { 186 led_set_brightness_nopm(led_cdev, led_cdev->brightness); 187 188 if (led_cdev->flash_resume) 189 led_cdev->flash_resume(led_cdev); 190 191 led_cdev->flags &= ~LED_SUSPENDED; 192 } 193 EXPORT_SYMBOL_GPL(led_classdev_resume); 194 195 #ifdef CONFIG_PM_SLEEP 196 static int led_suspend(struct device *dev) 197 { 198 struct led_classdev *led_cdev = dev_get_drvdata(dev); 199 200 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 201 led_classdev_suspend(led_cdev); 202 203 return 0; 204 } 205 206 static int led_resume(struct device *dev) 207 { 208 struct led_classdev *led_cdev = dev_get_drvdata(dev); 209 210 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 211 led_classdev_resume(led_cdev); 212 213 return 0; 214 } 215 #endif 216 217 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume); 218 219 /** 220 * of_led_get() - request a LED device via the LED framework 221 * @np: device node to get the LED device from 222 * @index: the index of the LED 223 * 224 * Returns the LED device parsed from the phandle specified in the "leds" 225 * property of a device tree node or a negative error-code on failure. 226 */ 227 struct led_classdev *of_led_get(struct device_node *np, int index) 228 { 229 struct device *led_dev; 230 struct led_classdev *led_cdev; 231 struct device_node *led_node; 232 233 led_node = of_parse_phandle(np, "leds", index); 234 if (!led_node) 235 return ERR_PTR(-ENOENT); 236 237 led_dev = class_find_device_by_of_node(leds_class, led_node); 238 of_node_put(led_node); 239 240 if (!led_dev) 241 return ERR_PTR(-EPROBE_DEFER); 242 243 led_cdev = dev_get_drvdata(led_dev); 244 245 if (!try_module_get(led_cdev->dev->parent->driver->owner)) 246 return ERR_PTR(-ENODEV); 247 248 return led_cdev; 249 } 250 EXPORT_SYMBOL_GPL(of_led_get); 251 252 /** 253 * led_put() - release a LED device 254 * @led_cdev: LED device 255 */ 256 void led_put(struct led_classdev *led_cdev) 257 { 258 module_put(led_cdev->dev->parent->driver->owner); 259 } 260 EXPORT_SYMBOL_GPL(led_put); 261 262 static void devm_led_release(struct device *dev, void *res) 263 { 264 struct led_classdev **p = res; 265 266 led_put(*p); 267 } 268 269 /** 270 * devm_of_led_get - Resource-managed request of a LED device 271 * @dev: LED consumer 272 * @index: index of the LED to obtain in the consumer 273 * 274 * The device node of the device is parse to find the request LED device. 275 * The LED device returned from this function is automatically released 276 * on driver detach. 277 * 278 * @return a pointer to a LED device or ERR_PTR(errno) on failure. 279 */ 280 struct led_classdev *__must_check devm_of_led_get(struct device *dev, 281 int index) 282 { 283 struct led_classdev *led; 284 struct led_classdev **dr; 285 286 if (!dev) 287 return ERR_PTR(-EINVAL); 288 289 /* Not using device tree? */ 290 if (!IS_ENABLED(CONFIG_OF) || !dev->of_node) 291 return ERR_PTR(-ENOTSUPP); 292 293 led = of_led_get(dev->of_node, index); 294 if (IS_ERR(led)) 295 return led; 296 297 dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), 298 GFP_KERNEL); 299 if (!dr) { 300 led_put(led); 301 return ERR_PTR(-ENOMEM); 302 } 303 304 *dr = led; 305 devres_add(dev, dr); 306 307 return led; 308 } 309 EXPORT_SYMBOL_GPL(devm_of_led_get); 310 311 static int led_classdev_next_name(const char *init_name, char *name, 312 size_t len) 313 { 314 unsigned int i = 0; 315 int ret = 0; 316 struct device *dev; 317 318 strlcpy(name, init_name, len); 319 320 while ((ret < len) && 321 (dev = class_find_device_by_name(leds_class, name))) { 322 put_device(dev); 323 ret = snprintf(name, len, "%s_%u", init_name, ++i); 324 } 325 326 if (ret >= len) 327 return -ENOMEM; 328 329 return i; 330 } 331 332 /** 333 * led_classdev_register_ext - register a new object of led_classdev class 334 * with init data. 335 * 336 * @parent: parent of LED device 337 * @led_cdev: the led_classdev structure for this device. 338 * @init_data: LED class device initialization data 339 */ 340 int led_classdev_register_ext(struct device *parent, 341 struct led_classdev *led_cdev, 342 struct led_init_data *init_data) 343 { 344 char composed_name[LED_MAX_NAME_SIZE]; 345 char final_name[LED_MAX_NAME_SIZE]; 346 const char *proposed_name = composed_name; 347 int ret; 348 349 if (init_data) { 350 if (init_data->devname_mandatory && !init_data->devicename) { 351 dev_err(parent, "Mandatory device name is missing"); 352 return -EINVAL; 353 } 354 ret = led_compose_name(parent, init_data, composed_name); 355 if (ret < 0) 356 return ret; 357 358 if (init_data->fwnode) 359 fwnode_property_read_string(init_data->fwnode, 360 "linux,default-trigger", 361 &led_cdev->default_trigger); 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 led_set_brightness(led_cdev, LED_OFF); 453 454 flush_work(&led_cdev->set_brightness_work); 455 456 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) 457 led_remove_brightness_hw_changed(led_cdev); 458 459 device_unregister(led_cdev->dev); 460 461 down_write(&leds_list_lock); 462 list_del(&led_cdev->node); 463 up_write(&leds_list_lock); 464 465 mutex_destroy(&led_cdev->led_access); 466 } 467 EXPORT_SYMBOL_GPL(led_classdev_unregister); 468 469 static void devm_led_classdev_release(struct device *dev, void *res) 470 { 471 led_classdev_unregister(*(struct led_classdev **)res); 472 } 473 474 /** 475 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext() 476 * 477 * @parent: parent of LED device 478 * @led_cdev: the led_classdev structure for this device. 479 * @init_data: LED class device initialization data 480 */ 481 int devm_led_classdev_register_ext(struct device *parent, 482 struct led_classdev *led_cdev, 483 struct led_init_data *init_data) 484 { 485 struct led_classdev **dr; 486 int rc; 487 488 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL); 489 if (!dr) 490 return -ENOMEM; 491 492 rc = led_classdev_register_ext(parent, led_cdev, init_data); 493 if (rc) { 494 devres_free(dr); 495 return rc; 496 } 497 498 *dr = led_cdev; 499 devres_add(parent, dr); 500 501 return 0; 502 } 503 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext); 504 505 static int devm_led_classdev_match(struct device *dev, void *res, void *data) 506 { 507 struct led_classdev **p = res; 508 509 if (WARN_ON(!p || !*p)) 510 return 0; 511 512 return *p == data; 513 } 514 515 /** 516 * devm_led_classdev_unregister() - resource managed led_classdev_unregister() 517 * @parent: The device to unregister. 518 * @led_cdev: the led_classdev structure for this device. 519 */ 520 void devm_led_classdev_unregister(struct device *dev, 521 struct led_classdev *led_cdev) 522 { 523 WARN_ON(devres_release(dev, 524 devm_led_classdev_release, 525 devm_led_classdev_match, led_cdev)); 526 } 527 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister); 528 529 static int __init leds_init(void) 530 { 531 leds_class = class_create(THIS_MODULE, "leds"); 532 if (IS_ERR(leds_class)) 533 return PTR_ERR(leds_class); 534 leds_class->pm = &leds_class_dev_pm_ops; 535 leds_class->dev_groups = led_groups; 536 return 0; 537 } 538 539 static void __exit leds_exit(void) 540 { 541 class_destroy(leds_class); 542 } 543 544 subsys_initcall(leds_init); 545 module_exit(leds_exit); 546 547 MODULE_AUTHOR("John Lenz, Richard Purdie"); 548 MODULE_LICENSE("GPL"); 549 MODULE_DESCRIPTION("LED Class Interface"); 550