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
  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         led = of_led_get(dev->of_node, index);
 290         if (IS_ERR(led))
 291                 return led;
 292
 293         dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
 294                           GFP_KERNEL);
 295         if (!dr) {
 296                 led_put(led);
 297                 return ERR_PTR(-ENOMEM);
 298         }
 299
 300         *dr = led;
 301         devres_add(dev, dr);
 302
 303         return led;
 304 }
 305 EXPORT_SYMBOL_GPL(devm_of_led_get);
 306
 307 static int led_classdev_next_name(const char *init_name, char *name,
 308                                   size_t len)
 309 {
 310         unsigned int i = 0;
 311         int ret = 0;
 312         struct device *dev;
 313
 314         strlcpy(name, init_name, len);
 315
 316         while ((ret < len) &&
 317                (dev = class_find_device_by_name(leds_class, name))) {
 318                 put_device(dev);
 319                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 320         }
 321
 322         if (ret >= len)
 323                 return -ENOMEM;
 324
 325         return i;
 326 }
 327
 328 /**
 329  * led_classdev_register_ext - register a new object of led_classdev class
 330  *                             with init data.
 331  *
 332  * @parent: parent of LED device
 333  * @led_cdev: the led_classdev structure for this device.
 334  * @init_data: LED class device initialization data
 335  */
 336 int led_classdev_register_ext(struct device *parent,
 337                               struct led_classdev *led_cdev,
 338                               struct led_init_data *init_data)
 339 {
 340         char composed_name[LED_MAX_NAME_SIZE];
 341         char final_name[LED_MAX_NAME_SIZE];
 342         const char *proposed_name = composed_name;
 343         int ret;
 344
 345         if (init_data) {
 346                 if (init_data->devname_mandatory && !init_data->devicename) {
 347                         dev_err(parent, "Mandatory device name is missing");
 348                         return -EINVAL;
 349                 }
 350                 ret = led_compose_name(parent, init_data, composed_name);
 351                 if (ret < 0)
 352                         return ret;
 353
 354                 if (init_data->fwnode)
 355                         fwnode_property_read_string(init_data->fwnode,
 356                                 "linux,default-trigger",
 357                                 &led_cdev->default_trigger);
 358         } else {
 359                 proposed_name = led_cdev->name;
 360         }
 361
 362         ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
 363         if (ret < 0)
 364                 return ret;
 365
 366         mutex_init(&led_cdev->led_access);
 367         mutex_lock(&led_cdev->led_access);
 368         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 369                                 led_cdev, led_cdev->groups, "%s", final_name);
 370         if (IS_ERR(led_cdev->dev)) {
 371                 mutex_unlock(&led_cdev->led_access);
 372                 return PTR_ERR(led_cdev->dev);
 373         }
 374         if (init_data && init_data->fwnode) {
 375                 led_cdev->dev->fwnode = init_data->fwnode;
 376                 led_cdev->dev->of_node = to_of_node(init_data->fwnode);
 377         }
 378
 379         if (ret)
 380                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 381                                 proposed_name, dev_name(led_cdev->dev));
 382
 383         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 384                 ret = led_add_brightness_hw_changed(led_cdev);
 385                 if (ret) {
 386                         device_unregister(led_cdev->dev);
 387                         led_cdev->dev = NULL;
 388                         mutex_unlock(&led_cdev->led_access);
 389                         return ret;
 390                 }
 391         }
 392
 393         led_cdev->work_flags = 0;
 394 #ifdef CONFIG_LEDS_TRIGGERS
 395         init_rwsem(&led_cdev->trigger_lock);
 396 #endif
 397 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 398         led_cdev->brightness_hw_changed = -1;
 399 #endif
 400         /* add to the list of leds */
 401         down_write(&leds_list_lock);
 402         list_add_tail(&led_cdev->node, &leds_list);
 403         up_write(&leds_list_lock);
 404
 405         if (!led_cdev->max_brightness)
 406                 led_cdev->max_brightness = LED_FULL;
 407
 408         led_update_brightness(led_cdev);
 409
 410         led_init_core(led_cdev);
 411
 412 #ifdef CONFIG_LEDS_TRIGGERS
 413         led_trigger_set_default(led_cdev);
 414 #endif
 415
 416         mutex_unlock(&led_cdev->led_access);
 417
 418         dev_dbg(parent, "Registered led device: %s\n",
 419                         led_cdev->name);
 420
 421         return 0;
 422 }
 423 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
 424
 425 /**
 426  * led_classdev_unregister - unregisters a object of led_properties class.
 427  * @led_cdev: the led device to unregister
 428  *
 429  * Unregisters a previously registered via led_classdev_register object.
 430  */
 431 void led_classdev_unregister(struct led_classdev *led_cdev)
 432 {
 433         if (IS_ERR_OR_NULL(led_cdev->dev))
 434                 return;
 435
 436 #ifdef CONFIG_LEDS_TRIGGERS
 437         down_write(&led_cdev->trigger_lock);
 438         if (led_cdev->trigger)
 439                 led_trigger_set(led_cdev, NULL);
 440         up_write(&led_cdev->trigger_lock);
 441 #endif
 442
 443         led_cdev->flags |= LED_UNREGISTERING;
 444
 445         /* Stop blinking */
 446         led_stop_software_blink(led_cdev);
 447
 448         led_set_brightness(led_cdev, LED_OFF);
 449
 450         flush_work(&led_cdev->set_brightness_work);
 451
 452         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
 453                 led_remove_brightness_hw_changed(led_cdev);
 454
 455         device_unregister(led_cdev->dev);
 456
 457         down_write(&leds_list_lock);
 458         list_del(&led_cdev->node);
 459         up_write(&leds_list_lock);
 460
 461         mutex_destroy(&led_cdev->led_access);
 462 }
 463 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 464
 465 static void devm_led_classdev_release(struct device *dev, void *res)
 466 {
 467         led_classdev_unregister(*(struct led_classdev **)res);
 468 }
 469
 470 /**
 471  * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
 472  *
 473  * @parent: parent of LED device
 474  * @led_cdev: the led_classdev structure for this device.
 475  * @init_data: LED class device initialization data
 476  */
 477 int devm_led_classdev_register_ext(struct device *parent,
 478                                    struct led_classdev *led_cdev,
 479                                    struct led_init_data *init_data)
 480 {
 481         struct led_classdev **dr;
 482         int rc;
 483
 484         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 485         if (!dr)
 486                 return -ENOMEM;
 487
 488         rc = led_classdev_register_ext(parent, led_cdev, init_data);
 489         if (rc) {
 490                 devres_free(dr);
 491                 return rc;
 492         }
 493
 494         *dr = led_cdev;
 495         devres_add(parent, dr);
 496
 497         return 0;
 498 }
 499 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
 500
 501 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 502 {
 503         struct led_classdev **p = res;
 504
 505         if (WARN_ON(!p || !*p))
 506                 return 0;
 507
 508         return *p == data;
 509 }
 510
 511 /**
 512  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 513  * @parent: The device to unregister.
 514  * @led_cdev: the led_classdev structure for this device.
 515  */
 516 void devm_led_classdev_unregister(struct device *dev,
 517                                   struct led_classdev *led_cdev)
 518 {
 519         WARN_ON(devres_release(dev,
 520                                devm_led_classdev_release,
 521                                devm_led_classdev_match, led_cdev));
 522 }
 523 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 524
 525 static int __init leds_init(void)
 526 {
 527         leds_class = class_create(THIS_MODULE, "leds");
 528         if (IS_ERR(leds_class))
 529                 return PTR_ERR(leds_class);
 530         leds_class->pm = &leds_class_dev_pm_ops;
 531         leds_class->dev_groups = led_groups;
 532         return 0;
 533 }
 534
 535 static void __exit leds_exit(void)
 536 {
 537         class_destroy(leds_class);
 538 }
 539
 540 subsys_initcall(leds_init);
 541 module_exit(leds_exit);
 542
 543 MODULE_AUTHOR("John Lenz, Richard Purdie");
 544 MODULE_LICENSE("GPL");
 545 MODULE_DESCRIPTION("LED Class Interface");