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
  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         led = of_led_get(dev->of_node, index);
 289         if (IS_ERR(led))
 290                 return led;
 291
 292         dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
 293                           GFP_KERNEL);
 294         if (!dr) {
 295                 led_put(led);
 296                 return ERR_PTR(-ENOMEM);
 297         }
 298
 299         *dr = led;
 300         devres_add(dev, dr);
 301
 302         return led;
 303 }
 304 EXPORT_SYMBOL_GPL(devm_of_led_get);
 305
 306 static int led_classdev_next_name(const char *init_name, char *name,
 307                                   size_t len)
 308 {
 309         unsigned int i = 0;
 310         int ret = 0;
 311         struct device *dev;
 312
 313         strlcpy(name, init_name, len);
 314
 315         while ((ret < len) &&
 316                (dev = class_find_device_by_name(leds_class, name))) {
 317                 put_device(dev);
 318                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 319         }
 320
 321         if (ret >= len)
 322                 return -ENOMEM;
 323
 324         return i;
 325 }
 326
 327 /**
 328  * led_classdev_register_ext - register a new object of led_classdev class
 329  *                             with init data.
 330  *
 331  * @parent: parent of LED device
 332  * @led_cdev: the led_classdev structure for this device.
 333  * @init_data: LED class device initialization data
 334  */
 335 int led_classdev_register_ext(struct device *parent,
 336                               struct led_classdev *led_cdev,
 337                               struct led_init_data *init_data)
 338 {
 339         char composed_name[LED_MAX_NAME_SIZE];
 340         char final_name[LED_MAX_NAME_SIZE];
 341         const char *proposed_name = composed_name;
 342         int ret;
 343
 344         if (init_data) {
 345                 if (init_data->devname_mandatory && !init_data->devicename) {
 346                         dev_err(parent, "Mandatory device name is missing");
 347                         return -EINVAL;
 348                 }
 349                 ret = led_compose_name(parent, init_data, composed_name);
 350                 if (ret < 0)
 351                         return ret;
 352
 353                 if (init_data->fwnode) {
 354                         fwnode_property_read_string(init_data->fwnode,
 355                                 "linux,default-trigger",
 356                                 &led_cdev->default_trigger);
 357
 358                         if (fwnode_property_present(init_data->fwnode,
 359                                                     "retain-state-shutdown"))
 360                                 led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
 361                 }
 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                 device_set_node(led_cdev->dev, init_data->fwnode);
 380
 381         if (ret)
 382                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 383                                 proposed_name, dev_name(led_cdev->dev));
 384
 385         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 386                 ret = led_add_brightness_hw_changed(led_cdev);
 387                 if (ret) {
 388                         device_unregister(led_cdev->dev);
 389                         led_cdev->dev = NULL;
 390                         mutex_unlock(&led_cdev->led_access);
 391                         return ret;
 392                 }
 393         }
 394
 395         led_cdev->work_flags = 0;
 396 #ifdef CONFIG_LEDS_TRIGGERS
 397         init_rwsem(&led_cdev->trigger_lock);
 398 #endif
 399 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 400         led_cdev->brightness_hw_changed = -1;
 401 #endif
 402         /* add to the list of leds */
 403         down_write(&leds_list_lock);
 404         list_add_tail(&led_cdev->node, &leds_list);
 405         up_write(&leds_list_lock);
 406
 407         if (!led_cdev->max_brightness)
 408                 led_cdev->max_brightness = LED_FULL;
 409
 410         led_update_brightness(led_cdev);
 411
 412         led_init_core(led_cdev);
 413
 414 #ifdef CONFIG_LEDS_TRIGGERS
 415         led_trigger_set_default(led_cdev);
 416 #endif
 417
 418         mutex_unlock(&led_cdev->led_access);
 419
 420         dev_dbg(parent, "Registered led device: %s\n",
 421                         led_cdev->name);
 422
 423         return 0;
 424 }
 425 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
 426
 427 /**
 428  * led_classdev_unregister - unregisters a object of led_properties class.
 429  * @led_cdev: the led device to unregister
 430  *
 431  * Unregisters a previously registered via led_classdev_register object.
 432  */
 433 void led_classdev_unregister(struct led_classdev *led_cdev)
 434 {
 435         if (IS_ERR_OR_NULL(led_cdev->dev))
 436                 return;
 437
 438 #ifdef CONFIG_LEDS_TRIGGERS
 439         down_write(&led_cdev->trigger_lock);
 440         if (led_cdev->trigger)
 441                 led_trigger_set(led_cdev, NULL);
 442         up_write(&led_cdev->trigger_lock);
 443 #endif
 444
 445         led_cdev->flags |= LED_UNREGISTERING;
 446
 447         /* Stop blinking */
 448         led_stop_software_blink(led_cdev);
 449
 450         if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
 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  * @dev: 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");