drivers/leds/led-class.c

   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 DEFINE_MUTEX(leds_lookup_lock);
  26 static LIST_HEAD(leds_lookup_list);
  27
  28 static ssize_t brightness_show(struct device *dev,
  29                 struct device_attribute *attr, char *buf)
  30 {
  31         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  32
  33         /* no lock needed for this */
  34         led_update_brightness(led_cdev);
  35
  36         return sprintf(buf, "%u\n", led_cdev->brightness);
  37 }
  38
  39 static ssize_t brightness_store(struct device *dev,
  40                 struct device_attribute *attr, const char *buf, size_t size)
  41 {
  42         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  43         unsigned long state;
  44         ssize_t ret;
  45
  46         mutex_lock(&led_cdev->led_access);
  47
  48         if (led_sysfs_is_disabled(led_cdev)) {
  49                 ret = -EBUSY;
  50                 goto unlock;
  51         }
  52
  53         ret = kstrtoul(buf, 10, &state);
  54         if (ret)
  55                 goto unlock;
  56
  57         if (state == LED_OFF)
  58                 led_trigger_remove(led_cdev);
  59         led_set_brightness(led_cdev, state);
  60         flush_work(&led_cdev->set_brightness_work);
  61
  62         ret = size;
  63 unlock:
  64         mutex_unlock(&led_cdev->led_access);
  65         return ret;
  66 }
  67 static DEVICE_ATTR_RW(brightness);
  68
  69 static ssize_t max_brightness_show(struct device *dev,
  70                 struct device_attribute *attr, char *buf)
  71 {
  72         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  73
  74         return sprintf(buf, "%u\n", led_cdev->max_brightness);
  75 }
  76 static DEVICE_ATTR_RO(max_brightness);
  77
  78 #ifdef CONFIG_LEDS_TRIGGERS
  79 static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
  80 static struct bin_attribute *led_trigger_bin_attrs[] = {
  81         &bin_attr_trigger,
  82         NULL,
  83 };
  84 static const struct attribute_group led_trigger_group = {
  85         .bin_attrs = led_trigger_bin_attrs,
  86 };
  87 #endif
  88
  89 static struct attribute *led_class_attrs[] = {
  90         &dev_attr_brightness.attr,
  91         &dev_attr_max_brightness.attr,
  92         NULL,
  93 };
  94
  95 static const struct attribute_group led_group = {
  96         .attrs = led_class_attrs,
  97 };
  98
  99 static const struct attribute_group *led_groups[] = {
 100         &led_group,
 101 #ifdef CONFIG_LEDS_TRIGGERS
 102         &led_trigger_group,
 103 #endif
 104         NULL,
 105 };
 106
 107 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 108 static ssize_t brightness_hw_changed_show(struct device *dev,
 109                 struct device_attribute *attr, char *buf)
 110 {
 111         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 112
 113         if (led_cdev->brightness_hw_changed == -1)
 114                 return -ENODATA;
 115
 116         return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
 117 }
 118
 119 static DEVICE_ATTR_RO(brightness_hw_changed);
 120
 121 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 122 {
 123         struct device *dev = led_cdev->dev;
 124         int ret;
 125
 126         ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
 127         if (ret) {
 128                 dev_err(dev, "Error creating brightness_hw_changed\n");
 129                 return ret;
 130         }
 131
 132         led_cdev->brightness_hw_changed_kn =
 133                 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
 134         if (!led_cdev->brightness_hw_changed_kn) {
 135                 dev_err(dev, "Error getting brightness_hw_changed kn\n");
 136                 device_remove_file(dev, &dev_attr_brightness_hw_changed);
 137                 return -ENXIO;
 138         }
 139
 140         return 0;
 141 }
 142
 143 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 144 {
 145         sysfs_put(led_cdev->brightness_hw_changed_kn);
 146         device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
 147 }
 148
 149 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int 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 static struct led_classdev *led_module_get(struct device *led_dev)
 220 {
 221         struct led_classdev *led_cdev;
 222
 223         if (!led_dev)
 224                 return ERR_PTR(-EPROBE_DEFER);
 225
 226         led_cdev = dev_get_drvdata(led_dev);
 227
 228         if (!try_module_get(led_cdev->dev->parent->driver->owner)) {
 229                 put_device(led_cdev->dev);
 230                 return ERR_PTR(-ENODEV);
 231         }
 232
 233         return led_cdev;
 234 }
 235
 236 static const struct class leds_class = {
 237         .name = "leds",
 238         .dev_groups = led_groups,
 239         .pm = &leds_class_dev_pm_ops,
 240 };
 241
 242 /**
 243  * of_led_get() - request a LED device via the LED framework
 244  * @np: device node to get the LED device from
 245  * @index: the index of the LED
 246  *
 247  * Returns the LED device parsed from the phandle specified in the "leds"
 248  * property of a device tree node or a negative error-code on failure.
 249  */
 250 struct led_classdev *of_led_get(struct device_node *np, int index)
 251 {
 252         struct device *led_dev;
 253         struct device_node *led_node;
 254
 255         led_node = of_parse_phandle(np, "leds", index);
 256         if (!led_node)
 257                 return ERR_PTR(-ENOENT);
 258
 259         led_dev = class_find_device_by_of_node(&leds_class, led_node);
 260         of_node_put(led_node);
 261
 262         return led_module_get(led_dev);
 263 }
 264 EXPORT_SYMBOL_GPL(of_led_get);
 265
 266 /**
 267  * led_put() - release a LED device
 268  * @led_cdev: LED device
 269  */
 270 void led_put(struct led_classdev *led_cdev)
 271 {
 272         module_put(led_cdev->dev->parent->driver->owner);
 273         put_device(led_cdev->dev);
 274 }
 275 EXPORT_SYMBOL_GPL(led_put);
 276
 277 static void devm_led_release(struct device *dev, void *res)
 278 {
 279         struct led_classdev **p = res;
 280
 281         led_put(*p);
 282 }
 283
 284 static struct led_classdev *__devm_led_get(struct device *dev, struct led_classdev *led)
 285 {
 286         struct led_classdev **dr;
 287
 288         dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), GFP_KERNEL);
 289         if (!dr) {
 290                 led_put(led);
 291                 return ERR_PTR(-ENOMEM);
 292         }
 293
 294         *dr = led;
 295         devres_add(dev, dr);
 296
 297         return led;
 298 }
 299
 300 /**
 301  * devm_of_led_get - Resource-managed request of a LED device
 302  * @dev:        LED consumer
 303  * @index:      index of the LED to obtain in the consumer
 304  *
 305  * The device node of the device is parse to find the request LED device.
 306  * The LED device returned from this function is automatically released
 307  * on driver detach.
 308  *
 309  * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 310  */
 311 struct led_classdev *__must_check devm_of_led_get(struct device *dev,
 312                                                   int index)
 313 {
 314         struct led_classdev *led;
 315
 316         if (!dev)
 317                 return ERR_PTR(-EINVAL);
 318
 319         led = of_led_get(dev->of_node, index);
 320         if (IS_ERR(led))
 321                 return led;
 322
 323         return __devm_led_get(dev, led);
 324 }
 325 EXPORT_SYMBOL_GPL(devm_of_led_get);
 326
 327 /**
 328  * led_get() - request a LED device via the LED framework
 329  * @dev: device for which to get the LED device
 330  * @con_id: name of the LED from the device's point of view
 331  *
 332  * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 333  */
 334 struct led_classdev *led_get(struct device *dev, char *con_id)
 335 {
 336         struct led_lookup_data *lookup;
 337         const char *provider = NULL;
 338         struct device *led_dev;
 339
 340         mutex_lock(&leds_lookup_lock);
 341         list_for_each_entry(lookup, &leds_lookup_list, list) {
 342                 if (!strcmp(lookup->dev_id, dev_name(dev)) &&
 343                     !strcmp(lookup->con_id, con_id)) {
 344                         provider = kstrdup_const(lookup->provider, GFP_KERNEL);
 345                         break;
 346                 }
 347         }
 348         mutex_unlock(&leds_lookup_lock);
 349
 350         if (!provider)
 351                 return ERR_PTR(-ENOENT);
 352
 353         led_dev = class_find_device_by_name(&leds_class, provider);
 354         kfree_const(provider);
 355
 356         return led_module_get(led_dev);
 357 }
 358 EXPORT_SYMBOL_GPL(led_get);
 359
 360 /**
 361  * devm_led_get() - request a LED device via the LED framework
 362  * @dev: device for which to get the LED device
 363  * @con_id: name of the LED from the device's point of view
 364  *
 365  * The LED device returned from this function is automatically released
 366  * on driver detach.
 367  *
 368  * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 369  */
 370 struct led_classdev *devm_led_get(struct device *dev, char *con_id)
 371 {
 372         struct led_classdev *led;
 373
 374         led = led_get(dev, con_id);
 375         if (IS_ERR(led))
 376                 return led;
 377
 378         return __devm_led_get(dev, led);
 379 }
 380 EXPORT_SYMBOL_GPL(devm_led_get);
 381
 382 /**
 383  * led_add_lookup() - Add a LED lookup table entry
 384  * @led_lookup: the lookup table entry to add
 385  *
 386  * Add a LED lookup table entry. On systems without devicetree the lookup table
 387  * is used by led_get() to find LEDs.
 388  */
 389 void led_add_lookup(struct led_lookup_data *led_lookup)
 390 {
 391         mutex_lock(&leds_lookup_lock);
 392         list_add_tail(&led_lookup->list, &leds_lookup_list);
 393         mutex_unlock(&leds_lookup_lock);
 394 }
 395 EXPORT_SYMBOL_GPL(led_add_lookup);
 396
 397 /**
 398  * led_remove_lookup() - Remove a LED lookup table entry
 399  * @led_lookup: the lookup table entry to remove
 400  */
 401 void led_remove_lookup(struct led_lookup_data *led_lookup)
 402 {
 403         mutex_lock(&leds_lookup_lock);
 404         list_del(&led_lookup->list);
 405         mutex_unlock(&leds_lookup_lock);
 406 }
 407 EXPORT_SYMBOL_GPL(led_remove_lookup);
 408
 409 /**
 410  * devm_of_led_get_optional - Resource-managed request of an optional LED device
 411  * @dev:        LED consumer
 412  * @index:      index of the LED to obtain in the consumer
 413  *
 414  * The device node of the device is parsed to find the requested LED device.
 415  * The LED device returned from this function is automatically released
 416  * on driver detach.
 417  *
 418  * @return a pointer to a LED device, ERR_PTR(errno) on failure and NULL if the
 419  * led was not found.
 420  */
 421 struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
 422                                                         int index)
 423 {
 424         struct led_classdev *led;
 425
 426         led = devm_of_led_get(dev, index);
 427         if (IS_ERR(led) && PTR_ERR(led) == -ENOENT)
 428                 return NULL;
 429
 430         return led;
 431 }
 432 EXPORT_SYMBOL_GPL(devm_of_led_get_optional);
 433
 434 static int led_classdev_next_name(const char *init_name, char *name,
 435                                   size_t len)
 436 {
 437         unsigned int i = 0;
 438         int ret = 0;
 439         struct device *dev;
 440
 441         strscpy(name, init_name, len);
 442
 443         while ((ret < len) &&
 444                (dev = class_find_device_by_name(&leds_class, name))) {
 445                 put_device(dev);
 446                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 447         }
 448
 449         if (ret >= len)
 450                 return -ENOMEM;
 451
 452         return i;
 453 }
 454
 455 /**
 456  * led_classdev_register_ext - register a new object of led_classdev class
 457  *                             with init data.
 458  *
 459  * @parent: parent of LED device
 460  * @led_cdev: the led_classdev structure for this device.
 461  * @init_data: LED class device initialization data
 462  */
 463 int led_classdev_register_ext(struct device *parent,
 464                               struct led_classdev *led_cdev,
 465                               struct led_init_data *init_data)
 466 {
 467         char composed_name[LED_MAX_NAME_SIZE];
 468         char final_name[LED_MAX_NAME_SIZE];
 469         const char *proposed_name = composed_name;
 470         int ret;
 471
 472         if (init_data) {
 473                 if (init_data->devname_mandatory && !init_data->devicename) {
 474                         dev_err(parent, "Mandatory device name is missing");
 475                         return -EINVAL;
 476                 }
 477                 ret = led_compose_name(parent, init_data, composed_name);
 478                 if (ret < 0)
 479                         return ret;
 480
 481                 if (init_data->fwnode) {
 482                         fwnode_property_read_string(init_data->fwnode,
 483                                 "linux,default-trigger",
 484                                 &led_cdev->default_trigger);
 485
 486                         if (fwnode_property_present(init_data->fwnode,
 487                                                     "retain-state-shutdown"))
 488                                 led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
 489
 490                         fwnode_property_read_u32(init_data->fwnode,
 491                                 "max-brightness",
 492                                 &led_cdev->max_brightness);
 493
 494                         if (fwnode_property_present(init_data->fwnode, "color"))
 495                                 fwnode_property_read_u32(init_data->fwnode, "color",
 496                                                          &led_cdev->color);
 497                 }
 498         } else {
 499                 proposed_name = led_cdev->name;
 500         }
 501
 502         ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
 503         if (ret < 0)
 504                 return ret;
 505         else if (ret && led_cdev->flags & LED_REJECT_NAME_CONFLICT)
 506                 return -EEXIST;
 507         else if (ret)
 508                 dev_warn(parent, "Led %s renamed to %s due to name collision\n",
 509                          proposed_name, final_name);
 510
 511         if (led_cdev->color >= LED_COLOR_ID_MAX)
 512                 dev_warn(parent, "LED %s color identifier out of range\n", final_name);
 513
 514         mutex_init(&led_cdev->led_access);
 515         mutex_lock(&led_cdev->led_access);
 516         led_cdev->dev = device_create_with_groups(&leds_class, parent, 0,
 517                                                   led_cdev, led_cdev->groups, "%s", final_name);
 518         if (IS_ERR(led_cdev->dev)) {
 519                 mutex_unlock(&led_cdev->led_access);
 520                 return PTR_ERR(led_cdev->dev);
 521         }
 522         if (init_data && init_data->fwnode)
 523                 device_set_node(led_cdev->dev, init_data->fwnode);
 524
 525         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 526                 ret = led_add_brightness_hw_changed(led_cdev);
 527                 if (ret) {
 528                         device_unregister(led_cdev->dev);
 529                         led_cdev->dev = NULL;
 530                         mutex_unlock(&led_cdev->led_access);
 531                         return ret;
 532                 }
 533         }
 534
 535         led_cdev->work_flags = 0;
 536 #ifdef CONFIG_LEDS_TRIGGERS
 537         init_rwsem(&led_cdev->trigger_lock);
 538 #endif
 539 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 540         led_cdev->brightness_hw_changed = -1;
 541 #endif
 542         /* add to the list of leds */
 543         down_write(&leds_list_lock);
 544         list_add_tail(&led_cdev->node, &leds_list);
 545         up_write(&leds_list_lock);
 546
 547         if (!led_cdev->max_brightness)
 548                 led_cdev->max_brightness = LED_FULL;
 549
 550         led_update_brightness(led_cdev);
 551
 552         led_init_core(led_cdev);
 553
 554 #ifdef CONFIG_LEDS_TRIGGERS
 555         led_trigger_set_default(led_cdev);
 556 #endif
 557
 558         mutex_unlock(&led_cdev->led_access);
 559
 560         dev_dbg(parent, "Registered led device: %s\n",
 561                         led_cdev->name);
 562
 563         return 0;
 564 }
 565 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
 566
 567 /**
 568  * led_classdev_unregister - unregisters a object of led_properties class.
 569  * @led_cdev: the led device to unregister
 570  *
 571  * Unregisters a previously registered via led_classdev_register object.
 572  */
 573 void led_classdev_unregister(struct led_classdev *led_cdev)
 574 {
 575         if (IS_ERR_OR_NULL(led_cdev->dev))
 576                 return;
 577
 578 #ifdef CONFIG_LEDS_TRIGGERS
 579         down_write(&led_cdev->trigger_lock);
 580         if (led_cdev->trigger)
 581                 led_trigger_set(led_cdev, NULL);
 582         up_write(&led_cdev->trigger_lock);
 583 #endif
 584
 585         led_cdev->flags |= LED_UNREGISTERING;
 586
 587         /* Stop blinking */
 588         led_stop_software_blink(led_cdev);
 589
 590         if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
 591                 led_set_brightness(led_cdev, LED_OFF);
 592
 593         flush_work(&led_cdev->set_brightness_work);
 594
 595         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
 596                 led_remove_brightness_hw_changed(led_cdev);
 597
 598         device_unregister(led_cdev->dev);
 599
 600         down_write(&leds_list_lock);
 601         list_del(&led_cdev->node);
 602         up_write(&leds_list_lock);
 603
 604         mutex_destroy(&led_cdev->led_access);
 605 }
 606 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 607
 608 static void devm_led_classdev_release(struct device *dev, void *res)
 609 {
 610         led_classdev_unregister(*(struct led_classdev **)res);
 611 }
 612
 613 /**
 614  * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
 615  *
 616  * @parent: parent of LED device
 617  * @led_cdev: the led_classdev structure for this device.
 618  * @init_data: LED class device initialization data
 619  */
 620 int devm_led_classdev_register_ext(struct device *parent,
 621                                    struct led_classdev *led_cdev,
 622                                    struct led_init_data *init_data)
 623 {
 624         struct led_classdev **dr;
 625         int rc;
 626
 627         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 628         if (!dr)
 629                 return -ENOMEM;
 630
 631         rc = led_classdev_register_ext(parent, led_cdev, init_data);
 632         if (rc) {
 633                 devres_free(dr);
 634                 return rc;
 635         }
 636
 637         *dr = led_cdev;
 638         devres_add(parent, dr);
 639
 640         return 0;
 641 }
 642 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
 643
 644 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 645 {
 646         struct led_classdev **p = res;
 647
 648         if (WARN_ON(!p || !*p))
 649                 return 0;
 650
 651         return *p == data;
 652 }
 653
 654 /**
 655  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 656  * @dev: The device to unregister.
 657  * @led_cdev: the led_classdev structure for this device.
 658  */
 659 void devm_led_classdev_unregister(struct device *dev,
 660                                   struct led_classdev *led_cdev)
 661 {
 662         WARN_ON(devres_release(dev,
 663                                devm_led_classdev_release,
 664                                devm_led_classdev_match, led_cdev));
 665 }
 666 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 667
 668 static int __init leds_init(void)
 669 {
 670         return class_register(&leds_class);
 671 }
 672
 673 static void __exit leds_exit(void)
 674 {
 675         class_unregister(&leds_class);
 676 }
 677
 678 subsys_initcall(leds_init);
 679 module_exit(leds_exit);
 680
 681 MODULE_AUTHOR("John Lenz, Richard Purdie");
 682 MODULE_LICENSE("GPL");
 683 MODULE_DESCRIPTION("LED Class Interface");