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 struct class *leds_class;
  26 static DEFINE_MUTEX(leds_lookup_lock);
  27 static LIST_HEAD(leds_lookup_list);
  28
  29 static ssize_t brightness_show(struct device *dev,
  30                 struct device_attribute *attr, char *buf)
  31 {
  32         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  33
  34         /* no lock needed for this */
  35         led_update_brightness(led_cdev);
  36
  37         return sprintf(buf, "%u\n", led_cdev->brightness);
  38 }
  39
  40 static ssize_t brightness_store(struct device *dev,
  41                 struct device_attribute *attr, const char *buf, size_t size)
  42 {
  43         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  44         unsigned long state;
  45         ssize_t ret;
  46
  47         mutex_lock(&led_cdev->led_access);
  48
  49         if (led_sysfs_is_disabled(led_cdev)) {
  50                 ret = -EBUSY;
  51                 goto unlock;
  52         }
  53
  54         ret = kstrtoul(buf, 10, &state);
  55         if (ret)
  56                 goto unlock;
  57
  58         if (state == LED_OFF)
  59                 led_trigger_remove(led_cdev);
  60         led_set_brightness(led_cdev, state);
  61         flush_work(&led_cdev->set_brightness_work);
  62
  63         ret = size;
  64 unlock:
  65         mutex_unlock(&led_cdev->led_access);
  66         return ret;
  67 }
  68 static DEVICE_ATTR_RW(brightness);
  69
  70 static ssize_t max_brightness_show(struct device *dev,
  71                 struct device_attribute *attr, char *buf)
  72 {
  73         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  74
  75         return sprintf(buf, "%u\n", led_cdev->max_brightness);
  76 }
  77 static DEVICE_ATTR_RO(max_brightness);
  78
  79 #ifdef CONFIG_LEDS_TRIGGERS
  80 static BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
  81 static struct bin_attribute *led_trigger_bin_attrs[] = {
  82         &bin_attr_trigger,
  83         NULL,
  84 };
  85 static const struct attribute_group led_trigger_group = {
  86         .bin_attrs = led_trigger_bin_attrs,
  87 };
  88 #endif
  89
  90 static struct attribute *led_class_attrs[] = {
  91         &dev_attr_brightness.attr,
  92         &dev_attr_max_brightness.attr,
  93         NULL,
  94 };
  95
  96 static const struct attribute_group led_group = {
  97         .attrs = led_class_attrs,
  98 };
  99
 100 static const struct attribute_group *led_groups[] = {
 101         &led_group,
 102 #ifdef CONFIG_LEDS_TRIGGERS
 103         &led_trigger_group,
 104 #endif
 105         NULL,
 106 };
 107
 108 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 109 static ssize_t brightness_hw_changed_show(struct device *dev,
 110                 struct device_attribute *attr, char *buf)
 111 {
 112         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 113
 114         if (led_cdev->brightness_hw_changed == -1)
 115                 return -ENODATA;
 116
 117         return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
 118 }
 119
 120 static DEVICE_ATTR_RO(brightness_hw_changed);
 121
 122 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 123 {
 124         struct device *dev = led_cdev->dev;
 125         int ret;
 126
 127         ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
 128         if (ret) {
 129                 dev_err(dev, "Error creating brightness_hw_changed\n");
 130                 return ret;
 131         }
 132
 133         led_cdev->brightness_hw_changed_kn =
 134                 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
 135         if (!led_cdev->brightness_hw_changed_kn) {
 136                 dev_err(dev, "Error getting brightness_hw_changed kn\n");
 137                 device_remove_file(dev, &dev_attr_brightness_hw_changed);
 138                 return -ENXIO;
 139         }
 140
 141         return 0;
 142 }
 143
 144 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 145 {
 146         sysfs_put(led_cdev->brightness_hw_changed_kn);
 147         device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
 148 }
 149
 150 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int brightness)
 151 {
 152         if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
 153                 return;
 154
 155         led_cdev->brightness_hw_changed = brightness;
 156         sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
 157 }
 158 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
 159 #else
 160 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 161 {
 162         return 0;
 163 }
 164 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 165 {
 166 }
 167 #endif
 168
 169 /**
 170  * led_classdev_suspend - suspend an led_classdev.
 171  * @led_cdev: the led_classdev to suspend.
 172  */
 173 void led_classdev_suspend(struct led_classdev *led_cdev)
 174 {
 175         led_cdev->flags |= LED_SUSPENDED;
 176         led_set_brightness_nopm(led_cdev, 0);
 177         flush_work(&led_cdev->set_brightness_work);
 178 }
 179 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 180
 181 /**
 182  * led_classdev_resume - resume an led_classdev.
 183  * @led_cdev: the led_classdev to resume.
 184  */
 185 void led_classdev_resume(struct led_classdev *led_cdev)
 186 {
 187         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 188
 189         if (led_cdev->flash_resume)
 190                 led_cdev->flash_resume(led_cdev);
 191
 192         led_cdev->flags &= ~LED_SUSPENDED;
 193 }
 194 EXPORT_SYMBOL_GPL(led_classdev_resume);
 195
 196 #ifdef CONFIG_PM_SLEEP
 197 static int led_suspend(struct device *dev)
 198 {
 199         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 200
 201         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 202                 led_classdev_suspend(led_cdev);
 203
 204         return 0;
 205 }
 206
 207 static int led_resume(struct device *dev)
 208 {
 209         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 210
 211         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 212                 led_classdev_resume(led_cdev);
 213
 214         return 0;
 215 }
 216 #endif
 217
 218 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 219
 220 static struct led_classdev *led_module_get(struct device *led_dev)
 221 {
 222         struct led_classdev *led_cdev;
 223
 224         if (!led_dev)
 225                 return ERR_PTR(-EPROBE_DEFER);
 226
 227         led_cdev = dev_get_drvdata(led_dev);
 228
 229         if (!try_module_get(led_cdev->dev->parent->driver->owner)) {
 230                 put_device(led_cdev->dev);
 231                 return ERR_PTR(-ENODEV);
 232         }
 233
 234         return led_cdev;
 235 }
 236
 237 /**
 238  * of_led_get() - request a LED device via the LED framework
 239  * @np: device node to get the LED device from
 240  * @index: the index of the LED
 241  *
 242  * Returns the LED device parsed from the phandle specified in the "leds"
 243  * property of a device tree node or a negative error-code on failure.
 244  */
 245 struct led_classdev *of_led_get(struct device_node *np, int index)
 246 {
 247         struct device *led_dev;
 248         struct device_node *led_node;
 249
 250         led_node = of_parse_phandle(np, "leds", index);
 251         if (!led_node)
 252                 return ERR_PTR(-ENOENT);
 253
 254         led_dev = class_find_device_by_of_node(leds_class, led_node);
 255         of_node_put(led_node);
 256         put_device(led_dev);
 257
 258         return led_module_get(led_dev);
 259 }
 260 EXPORT_SYMBOL_GPL(of_led_get);
 261
 262 /**
 263  * led_put() - release a LED device
 264  * @led_cdev: LED device
 265  */
 266 void led_put(struct led_classdev *led_cdev)
 267 {
 268         module_put(led_cdev->dev->parent->driver->owner);
 269         put_device(led_cdev->dev);
 270 }
 271 EXPORT_SYMBOL_GPL(led_put);
 272
 273 static void devm_led_release(struct device *dev, void *res)
 274 {
 275         struct led_classdev **p = res;
 276
 277         led_put(*p);
 278 }
 279
 280 static struct led_classdev *__devm_led_get(struct device *dev, struct led_classdev *led)
 281 {
 282         struct led_classdev **dr;
 283
 284         dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), GFP_KERNEL);
 285         if (!dr) {
 286                 led_put(led);
 287                 return ERR_PTR(-ENOMEM);
 288         }
 289
 290         *dr = led;
 291         devres_add(dev, dr);
 292
 293         return led;
 294 }
 295
 296 /**
 297  * devm_of_led_get - Resource-managed request of a LED device
 298  * @dev:        LED consumer
 299  * @index:      index of the LED to obtain in the consumer
 300  *
 301  * The device node of the device is parse to find the request LED device.
 302  * The LED device returned from this function is automatically released
 303  * on driver detach.
 304  *
 305  * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 306  */
 307 struct led_classdev *__must_check devm_of_led_get(struct device *dev,
 308                                                   int index)
 309 {
 310         struct led_classdev *led;
 311
 312         if (!dev)
 313                 return ERR_PTR(-EINVAL);
 314
 315         led = of_led_get(dev->of_node, index);
 316         if (IS_ERR(led))
 317                 return led;
 318
 319         return __devm_led_get(dev, led);
 320 }
 321 EXPORT_SYMBOL_GPL(devm_of_led_get);
 322
 323 /**
 324  * led_get() - request a LED device via the LED framework
 325  * @dev: device for which to get the LED device
 326  * @con_id: name of the LED from the device's point of view
 327  *
 328  * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 329  */
 330 struct led_classdev *led_get(struct device *dev, char *con_id)
 331 {
 332         struct led_lookup_data *lookup;
 333         const char *provider = NULL;
 334         struct device *led_dev;
 335
 336         mutex_lock(&leds_lookup_lock);
 337         list_for_each_entry(lookup, &leds_lookup_list, list) {
 338                 if (!strcmp(lookup->dev_id, dev_name(dev)) &&
 339                     !strcmp(lookup->con_id, con_id)) {
 340                         provider = kstrdup_const(lookup->provider, GFP_KERNEL);
 341                         break;
 342                 }
 343         }
 344         mutex_unlock(&leds_lookup_lock);
 345
 346         if (!provider)
 347                 return ERR_PTR(-ENOENT);
 348
 349         led_dev = class_find_device_by_name(leds_class, provider);
 350         kfree_const(provider);
 351
 352         return led_module_get(led_dev);
 353 }
 354 EXPORT_SYMBOL_GPL(led_get);
 355
 356 /**
 357  * devm_led_get() - request a LED device via the LED framework
 358  * @dev: device for which to get the LED device
 359  * @con_id: name of the LED from the device's point of view
 360  *
 361  * The LED device returned from this function is automatically released
 362  * on driver detach.
 363  *
 364  * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 365  */
 366 struct led_classdev *devm_led_get(struct device *dev, char *con_id)
 367 {
 368         struct led_classdev *led;
 369
 370         led = led_get(dev, con_id);
 371         if (IS_ERR(led))
 372                 return led;
 373
 374         return __devm_led_get(dev, led);
 375 }
 376 EXPORT_SYMBOL_GPL(devm_led_get);
 377
 378 /**
 379  * led_add_lookup() - Add a LED lookup table entry
 380  * @led_lookup: the lookup table entry to add
 381  *
 382  * Add a LED lookup table entry. On systems without devicetree the lookup table
 383  * is used by led_get() to find LEDs.
 384  */
 385 void led_add_lookup(struct led_lookup_data *led_lookup)
 386 {
 387         mutex_lock(&leds_lookup_lock);
 388         list_add_tail(&led_lookup->list, &leds_lookup_list);
 389         mutex_unlock(&leds_lookup_lock);
 390 }
 391 EXPORT_SYMBOL_GPL(led_add_lookup);
 392
 393 /**
 394  * led_remove_lookup() - Remove a LED lookup table entry
 395  * @led_lookup: the lookup table entry to remove
 396  */
 397 void led_remove_lookup(struct led_lookup_data *led_lookup)
 398 {
 399         mutex_lock(&leds_lookup_lock);
 400         list_del(&led_lookup->list);
 401         mutex_unlock(&leds_lookup_lock);
 402 }
 403 EXPORT_SYMBOL_GPL(led_remove_lookup);
 404
 405 static int led_classdev_next_name(const char *init_name, char *name,
 406                                   size_t len)
 407 {
 408         unsigned int i = 0;
 409         int ret = 0;
 410         struct device *dev;
 411
 412         strscpy(name, init_name, len);
 413
 414         while ((ret < len) &&
 415                (dev = class_find_device_by_name(leds_class, name))) {
 416                 put_device(dev);
 417                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 418         }
 419
 420         if (ret >= len)
 421                 return -ENOMEM;
 422
 423         return i;
 424 }
 425
 426 /**
 427  * led_classdev_register_ext - register a new object of led_classdev class
 428  *                             with init data.
 429  *
 430  * @parent: parent of LED device
 431  * @led_cdev: the led_classdev structure for this device.
 432  * @init_data: LED class device initialization data
 433  */
 434 int led_classdev_register_ext(struct device *parent,
 435                               struct led_classdev *led_cdev,
 436                               struct led_init_data *init_data)
 437 {
 438         char composed_name[LED_MAX_NAME_SIZE];
 439         char final_name[LED_MAX_NAME_SIZE];
 440         const char *proposed_name = composed_name;
 441         int ret;
 442
 443         if (init_data) {
 444                 if (init_data->devname_mandatory && !init_data->devicename) {
 445                         dev_err(parent, "Mandatory device name is missing");
 446                         return -EINVAL;
 447                 }
 448                 ret = led_compose_name(parent, init_data, composed_name);
 449                 if (ret < 0)
 450                         return ret;
 451
 452                 if (init_data->fwnode) {
 453                         fwnode_property_read_string(init_data->fwnode,
 454                                 "linux,default-trigger",
 455                                 &led_cdev->default_trigger);
 456
 457                         if (fwnode_property_present(init_data->fwnode,
 458                                                     "retain-state-shutdown"))
 459                                 led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
 460                 }
 461         } else {
 462                 proposed_name = led_cdev->name;
 463         }
 464
 465         ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
 466         if (ret < 0)
 467                 return ret;
 468
 469         mutex_init(&led_cdev->led_access);
 470         mutex_lock(&led_cdev->led_access);
 471         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 472                                 led_cdev, led_cdev->groups, "%s", final_name);
 473         if (IS_ERR(led_cdev->dev)) {
 474                 mutex_unlock(&led_cdev->led_access);
 475                 return PTR_ERR(led_cdev->dev);
 476         }
 477         if (init_data && init_data->fwnode)
 478                 device_set_node(led_cdev->dev, init_data->fwnode);
 479
 480         if (ret)
 481                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 482                                 proposed_name, dev_name(led_cdev->dev));
 483
 484         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 485                 ret = led_add_brightness_hw_changed(led_cdev);
 486                 if (ret) {
 487                         device_unregister(led_cdev->dev);
 488                         led_cdev->dev = NULL;
 489                         mutex_unlock(&led_cdev->led_access);
 490                         return ret;
 491                 }
 492         }
 493
 494         led_cdev->work_flags = 0;
 495 #ifdef CONFIG_LEDS_TRIGGERS
 496         init_rwsem(&led_cdev->trigger_lock);
 497 #endif
 498 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 499         led_cdev->brightness_hw_changed = -1;
 500 #endif
 501         /* add to the list of leds */
 502         down_write(&leds_list_lock);
 503         list_add_tail(&led_cdev->node, &leds_list);
 504         up_write(&leds_list_lock);
 505
 506         if (!led_cdev->max_brightness)
 507                 led_cdev->max_brightness = LED_FULL;
 508
 509         led_update_brightness(led_cdev);
 510
 511         led_init_core(led_cdev);
 512
 513 #ifdef CONFIG_LEDS_TRIGGERS
 514         led_trigger_set_default(led_cdev);
 515 #endif
 516
 517         mutex_unlock(&led_cdev->led_access);
 518
 519         dev_dbg(parent, "Registered led device: %s\n",
 520                         led_cdev->name);
 521
 522         return 0;
 523 }
 524 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
 525
 526 /**
 527  * led_classdev_unregister - unregisters a object of led_properties class.
 528  * @led_cdev: the led device to unregister
 529  *
 530  * Unregisters a previously registered via led_classdev_register object.
 531  */
 532 void led_classdev_unregister(struct led_classdev *led_cdev)
 533 {
 534         if (IS_ERR_OR_NULL(led_cdev->dev))
 535                 return;
 536
 537 #ifdef CONFIG_LEDS_TRIGGERS
 538         down_write(&led_cdev->trigger_lock);
 539         if (led_cdev->trigger)
 540                 led_trigger_set(led_cdev, NULL);
 541         up_write(&led_cdev->trigger_lock);
 542 #endif
 543
 544         led_cdev->flags |= LED_UNREGISTERING;
 545
 546         /* Stop blinking */
 547         led_stop_software_blink(led_cdev);
 548
 549         if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
 550                 led_set_brightness(led_cdev, LED_OFF);
 551
 552         flush_work(&led_cdev->set_brightness_work);
 553
 554         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
 555                 led_remove_brightness_hw_changed(led_cdev);
 556
 557         device_unregister(led_cdev->dev);
 558
 559         down_write(&leds_list_lock);
 560         list_del(&led_cdev->node);
 561         up_write(&leds_list_lock);
 562
 563         mutex_destroy(&led_cdev->led_access);
 564 }
 565 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 566
 567 static void devm_led_classdev_release(struct device *dev, void *res)
 568 {
 569         led_classdev_unregister(*(struct led_classdev **)res);
 570 }
 571
 572 /**
 573  * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
 574  *
 575  * @parent: parent of LED device
 576  * @led_cdev: the led_classdev structure for this device.
 577  * @init_data: LED class device initialization data
 578  */
 579 int devm_led_classdev_register_ext(struct device *parent,
 580                                    struct led_classdev *led_cdev,
 581                                    struct led_init_data *init_data)
 582 {
 583         struct led_classdev **dr;
 584         int rc;
 585
 586         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 587         if (!dr)
 588                 return -ENOMEM;
 589
 590         rc = led_classdev_register_ext(parent, led_cdev, init_data);
 591         if (rc) {
 592                 devres_free(dr);
 593                 return rc;
 594         }
 595
 596         *dr = led_cdev;
 597         devres_add(parent, dr);
 598
 599         return 0;
 600 }
 601 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
 602
 603 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 604 {
 605         struct led_classdev **p = res;
 606
 607         if (WARN_ON(!p || !*p))
 608                 return 0;
 609
 610         return *p == data;
 611 }
 612
 613 /**
 614  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 615  * @dev: The device to unregister.
 616  * @led_cdev: the led_classdev structure for this device.
 617  */
 618 void devm_led_classdev_unregister(struct device *dev,
 619                                   struct led_classdev *led_cdev)
 620 {
 621         WARN_ON(devres_release(dev,
 622                                devm_led_classdev_release,
 623                                devm_led_classdev_match, led_cdev));
 624 }
 625 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 626
 627 static int __init leds_init(void)
 628 {
 629         leds_class = class_create("leds");
 630         if (IS_ERR(leds_class))
 631                 return PTR_ERR(leds_class);
 632         leds_class->pm = &leds_class_dev_pm_ops;
 633         leds_class->dev_groups = led_groups;
 634         return 0;
 635 }
 636
 637 static void __exit leds_exit(void)
 638 {
 639         class_destroy(leds_class);
 640 }
 641
 642 subsys_initcall(leds_init);
 643 module_exit(leds_exit);
 644
 645 MODULE_AUTHOR("John Lenz, Richard Purdie");
 646 MODULE_LICENSE("GPL");
 647 MODULE_DESCRIPTION("LED Class Interface");