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 /* Not using device tree? */ 289 if (!IS_ENABLED(CONFIG_OF) || !dev->of_node) 290 return ERR_PTR(-ENOTSUPP); 291 292 led = of_led_get(dev->of_node, index); 293 if (IS_ERR(led)) 294 return led; 295 296 dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), 297 GFP_KERNEL); 298 if (!dr) { 299 led_put(led); 300 return ERR_PTR(-ENOMEM); 301 } 302 303 *dr = led; 304 devres_add(dev, dr); 305 306 return led; 307 } 308 EXPORT_SYMBOL_GPL(devm_of_led_get); 309 310 static int led_classdev_next_name(const char *init_name, char *name, 311 size_t len) 312 { 313 unsigned int i = 0; 314 int ret = 0; 315 struct device *dev; 316 317 strlcpy(name, init_name, len); 318 319 while ((ret < len) && 320 (dev = class_find_device_by_name(leds_class, name))) { 321 put_device(dev); 322 ret = snprintf(name, len, "%s_%u", init_name, ++i); 323 } 324 325 if (ret >= len) 326 return -ENOMEM; 327 328 return i; 329 } 330 331 /** 332 * led_classdev_register_ext - register a new object of led_classdev class 333 * with init data. 334 * 335 * @parent: parent of LED device 336 * @led_cdev: the led_classdev structure for this device. 337 * @init_data: LED class device initialization data 338 */ 339 int led_classdev_register_ext(struct device *parent, 340 struct led_classdev *led_cdev, 341 struct led_init_data *init_data) 342 { 343 char composed_name[LED_MAX_NAME_SIZE]; 344 char final_name[LED_MAX_NAME_SIZE]; 345 const char *proposed_name = composed_name; 346 int ret; 347 348 if (init_data) { 349 if (init_data->devname_mandatory && !init_data->devicename) { 350 dev_err(parent, "Mandatory device name is missing"); 351 return -EINVAL; 352 } 353 ret = led_compose_name(parent, init_data, composed_name); 354 if (ret < 0) 355 return ret; 356 357 if (init_data->fwnode) 358 fwnode_property_read_string(init_data->fwnode, 359 "linux,default-trigger", 360 &led_cdev->default_trigger); 361 } else { 362 proposed_name = led_cdev->name; 363 } 364 365 ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name)); 366 if (ret < 0) 367 return ret; 368 369 mutex_init(&led_cdev->led_access); 370 mutex_lock(&led_cdev->led_access); 371 led_cdev->dev = device_create_with_groups(leds_class, parent, 0, 372 led_cdev, led_cdev->groups, "%s", final_name); 373 if (IS_ERR(led_cdev->dev)) { 374 mutex_unlock(&led_cdev->led_access); 375 return PTR_ERR(led_cdev->dev); 376 } 377 if (init_data && init_data->fwnode) { 378 led_cdev->dev->fwnode = init_data->fwnode; 379 led_cdev->dev->of_node = to_of_node(init_data->fwnode); 380 } 381 382 if (ret) 383 dev_warn(parent, "Led %s renamed to %s due to name collision", 384 proposed_name, dev_name(led_cdev->dev)); 385 386 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) { 387 ret = led_add_brightness_hw_changed(led_cdev); 388 if (ret) { 389 device_unregister(led_cdev->dev); 390 led_cdev->dev = NULL; 391 mutex_unlock(&led_cdev->led_access); 392 return ret; 393 } 394 } 395 396 led_cdev->work_flags = 0; 397 #ifdef CONFIG_LEDS_TRIGGERS 398 init_rwsem(&led_cdev->trigger_lock); 399 #endif 400 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED 401 led_cdev->brightness_hw_changed = -1; 402 #endif 403 /* add to the list of leds */ 404 down_write(&leds_list_lock); 405 list_add_tail(&led_cdev->node, &leds_list); 406 up_write(&leds_list_lock); 407 408 if (!led_cdev->max_brightness) 409 led_cdev->max_brightness = LED_FULL; 410 411 led_update_brightness(led_cdev); 412 413 led_init_core(led_cdev); 414 415 #ifdef CONFIG_LEDS_TRIGGERS 416 led_trigger_set_default(led_cdev); 417 #endif 418 419 mutex_unlock(&led_cdev->led_access); 420 421 dev_dbg(parent, "Registered led device: %s\n", 422 led_cdev->name); 423 424 return 0; 425 } 426 EXPORT_SYMBOL_GPL(led_classdev_register_ext); 427 428 /** 429 * led_classdev_unregister - unregisters a object of led_properties class. 430 * @led_cdev: the led device to unregister 431 * 432 * Unregisters a previously registered via led_classdev_register object. 433 */ 434 void led_classdev_unregister(struct led_classdev *led_cdev) 435 { 436 if (IS_ERR_OR_NULL(led_cdev->dev)) 437 return; 438 439 #ifdef CONFIG_LEDS_TRIGGERS 440 down_write(&led_cdev->trigger_lock); 441 if (led_cdev->trigger) 442 led_trigger_set(led_cdev, NULL); 443 up_write(&led_cdev->trigger_lock); 444 #endif 445 446 led_cdev->flags |= LED_UNREGISTERING; 447 448 /* Stop blinking */ 449 led_stop_software_blink(led_cdev); 450 451 led_set_brightness(led_cdev, LED_OFF); 452 453 flush_work(&led_cdev->set_brightness_work); 454 455 if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) 456 led_remove_brightness_hw_changed(led_cdev); 457 458 device_unregister(led_cdev->dev); 459 460 down_write(&leds_list_lock); 461 list_del(&led_cdev->node); 462 up_write(&leds_list_lock); 463 464 mutex_destroy(&led_cdev->led_access); 465 } 466 EXPORT_SYMBOL_GPL(led_classdev_unregister); 467 468 static void devm_led_classdev_release(struct device *dev, void *res) 469 { 470 led_classdev_unregister(*(struct led_classdev **)res); 471 } 472 473 /** 474 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext() 475 * 476 * @parent: parent of LED device 477 * @led_cdev: the led_classdev structure for this device. 478 * @init_data: LED class device initialization data 479 */ 480 int devm_led_classdev_register_ext(struct device *parent, 481 struct led_classdev *led_cdev, 482 struct led_init_data *init_data) 483 { 484 struct led_classdev **dr; 485 int rc; 486 487 dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL); 488 if (!dr) 489 return -ENOMEM; 490 491 rc = led_classdev_register_ext(parent, led_cdev, init_data); 492 if (rc) { 493 devres_free(dr); 494 return rc; 495 } 496 497 *dr = led_cdev; 498 devres_add(parent, dr); 499 500 return 0; 501 } 502 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext); 503 504 static int devm_led_classdev_match(struct device *dev, void *res, void *data) 505 { 506 struct led_classdev **p = res; 507 508 if (WARN_ON(!p || !*p)) 509 return 0; 510 511 return *p == data; 512 } 513 514 /** 515 * devm_led_classdev_unregister() - resource managed led_classdev_unregister() 516 * @parent: The device to unregister. 517 * @led_cdev: the led_classdev structure for this device. 518 */ 519 void devm_led_classdev_unregister(struct device *dev, 520 struct led_classdev *led_cdev) 521 { 522 WARN_ON(devres_release(dev, 523 devm_led_classdev_release, 524 devm_led_classdev_match, led_cdev)); 525 } 526 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister); 527 528 static int __init leds_init(void) 529 { 530 leds_class = class_create(THIS_MODULE, "leds"); 531 if (IS_ERR(leds_class)) 532 return PTR_ERR(leds_class); 533 leds_class->pm = &leds_class_dev_pm_ops; 534 leds_class->dev_groups = led_groups; 535 return 0; 536 } 537 538 static void __exit leds_exit(void) 539 { 540 class_destroy(leds_class); 541 } 542 543 subsys_initcall(leds_init); 544 module_exit(leds_exit); 545 546 MODULE_AUTHOR("John Lenz, Richard Purdie"); 547 MODULE_LICENSE("GPL"); 548 MODULE_DESCRIPTION("LED Class Interface"); 549