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/of.h>
  18 #include <linux/slab.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/timer.h>
  21 #include <uapi/linux/uleds.h>
  22 #include "leds.h"
  23
  24 static struct class *leds_class;
  25
  26 static ssize_t brightness_show(struct device *dev,
  27                 struct device_attribute *attr, char *buf)
  28 {
  29         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  30
  31         /* no lock needed for this */
  32         led_update_brightness(led_cdev);
  33
  34         return sprintf(buf, "%u\n", led_cdev->brightness);
  35 }
  36
  37 static ssize_t brightness_store(struct device *dev,
  38                 struct device_attribute *attr, const char *buf, size_t size)
  39 {
  40         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  41         unsigned long state;
  42         ssize_t ret;
  43
  44         mutex_lock(&led_cdev->led_access);
  45
  46         if (led_sysfs_is_disabled(led_cdev)) {
  47                 ret = -EBUSY;
  48                 goto unlock;
  49         }
  50
  51         ret = kstrtoul(buf, 10, &state);
  52         if (ret)
  53                 goto unlock;
  54
  55         if (state == LED_OFF)
  56                 led_trigger_remove(led_cdev);
  57         led_set_brightness(led_cdev, state);
  58         flush_work(&led_cdev->set_brightness_work);
  59
  60         ret = size;
  61 unlock:
  62         mutex_unlock(&led_cdev->led_access);
  63         return ret;
  64 }
  65 static DEVICE_ATTR_RW(brightness);
  66
  67 static ssize_t max_brightness_show(struct device *dev,
  68                 struct device_attribute *attr, char *buf)
  69 {
  70         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  71
  72         return sprintf(buf, "%u\n", led_cdev->max_brightness);
  73 }
  74 static DEVICE_ATTR_RO(max_brightness);
  75
  76 #ifdef CONFIG_LEDS_TRIGGERS
  77 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  78 static struct attribute *led_trigger_attrs[] = {
  79         &dev_attr_trigger.attr,
  80         NULL,
  81 };
  82 static const struct attribute_group led_trigger_group = {
  83         .attrs = led_trigger_attrs,
  84 };
  85 #endif
  86
  87 static struct attribute *led_class_attrs[] = {
  88         &dev_attr_brightness.attr,
  89         &dev_attr_max_brightness.attr,
  90         NULL,
  91 };
  92
  93 static const struct attribute_group led_group = {
  94         .attrs = led_class_attrs,
  95 };
  96
  97 static const struct attribute_group *led_groups[] = {
  98         &led_group,
  99 #ifdef CONFIG_LEDS_TRIGGERS
 100         &led_trigger_group,
 101 #endif
 102         NULL,
 103 };
 104
 105 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 106 static ssize_t brightness_hw_changed_show(struct device *dev,
 107                 struct device_attribute *attr, char *buf)
 108 {
 109         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 110
 111         if (led_cdev->brightness_hw_changed == -1)
 112                 return -ENODATA;
 113
 114         return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
 115 }
 116
 117 static DEVICE_ATTR_RO(brightness_hw_changed);
 118
 119 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 120 {
 121         struct device *dev = led_cdev->dev;
 122         int ret;
 123
 124         ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
 125         if (ret) {
 126                 dev_err(dev, "Error creating brightness_hw_changed\n");
 127                 return ret;
 128         }
 129
 130         led_cdev->brightness_hw_changed_kn =
 131                 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
 132         if (!led_cdev->brightness_hw_changed_kn) {
 133                 dev_err(dev, "Error getting brightness_hw_changed kn\n");
 134                 device_remove_file(dev, &dev_attr_brightness_hw_changed);
 135                 return -ENXIO;
 136         }
 137
 138         return 0;
 139 }
 140
 141 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 142 {
 143         sysfs_put(led_cdev->brightness_hw_changed_kn);
 144         device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
 145 }
 146
 147 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev,
 148                                                enum led_brightness 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 }
 176 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 177
 178 /**
 179  * led_classdev_resume - resume an led_classdev.
 180  * @led_cdev: the led_classdev to resume.
 181  */
 182 void led_classdev_resume(struct led_classdev *led_cdev)
 183 {
 184         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 185
 186         if (led_cdev->flash_resume)
 187                 led_cdev->flash_resume(led_cdev);
 188
 189         led_cdev->flags &= ~LED_SUSPENDED;
 190 }
 191 EXPORT_SYMBOL_GPL(led_classdev_resume);
 192
 193 #ifdef CONFIG_PM_SLEEP
 194 static int led_suspend(struct device *dev)
 195 {
 196         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 197
 198         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 199                 led_classdev_suspend(led_cdev);
 200
 201         return 0;
 202 }
 203
 204 static int led_resume(struct device *dev)
 205 {
 206         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 207
 208         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 209                 led_classdev_resume(led_cdev);
 210
 211         return 0;
 212 }
 213 #endif
 214
 215 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 216
 217 static int match_name(struct device *dev, const void *data)
 218 {
 219         if (!dev_name(dev))
 220                 return 0;
 221         return !strcmp(dev_name(dev), (char *)data);
 222 }
 223
 224 static int led_classdev_next_name(const char *init_name, char *name,
 225                                   size_t len)
 226 {
 227         unsigned int i = 0;
 228         int ret = 0;
 229         struct device *dev;
 230
 231         strlcpy(name, init_name, len);
 232
 233         while ((ret < len) &&
 234                (dev = class_find_device(leds_class, NULL, name, match_name))) {
 235                 put_device(dev);
 236                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 237         }
 238
 239         if (ret >= len)
 240                 return -ENOMEM;
 241
 242         return i;
 243 }
 244
 245 /**
 246  * led_classdev_register_ext - register a new object of led_classdev class
 247  *                             with init data.
 248  *
 249  * @parent: parent of LED device
 250  * @led_cdev: the led_classdev structure for this device.
 251  * @init_data: LED class device initialization data
 252  */
 253 int led_classdev_register_ext(struct device *parent,
 254                               struct led_classdev *led_cdev,
 255                               struct led_init_data *init_data)
 256 {
 257         char name[LED_MAX_NAME_SIZE];
 258         int ret;
 259
 260         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 261         if (ret < 0)
 262                 return ret;
 263
 264         mutex_init(&led_cdev->led_access);
 265         mutex_lock(&led_cdev->led_access);
 266         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 267                                 led_cdev, led_cdev->groups, "%s", name);
 268         if (IS_ERR(led_cdev->dev)) {
 269                 mutex_unlock(&led_cdev->led_access);
 270                 return PTR_ERR(led_cdev->dev);
 271         }
 272         if (init_data && init_data->fwnode)
 273                 led_cdev->dev->of_node = to_of_node(init_data->fwnode);
 274
 275         if (ret)
 276                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 277                                 led_cdev->name, dev_name(led_cdev->dev));
 278
 279         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 280                 ret = led_add_brightness_hw_changed(led_cdev);
 281                 if (ret) {
 282                         device_unregister(led_cdev->dev);
 283                         mutex_unlock(&led_cdev->led_access);
 284                         return ret;
 285                 }
 286         }
 287
 288         led_cdev->work_flags = 0;
 289 #ifdef CONFIG_LEDS_TRIGGERS
 290         init_rwsem(&led_cdev->trigger_lock);
 291 #endif
 292 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 293         led_cdev->brightness_hw_changed = -1;
 294 #endif
 295         /* add to the list of leds */
 296         down_write(&leds_list_lock);
 297         list_add_tail(&led_cdev->node, &leds_list);
 298         up_write(&leds_list_lock);
 299
 300         if (!led_cdev->max_brightness)
 301                 led_cdev->max_brightness = LED_FULL;
 302
 303         led_update_brightness(led_cdev);
 304
 305         led_init_core(led_cdev);
 306
 307 #ifdef CONFIG_LEDS_TRIGGERS
 308         led_trigger_set_default(led_cdev);
 309 #endif
 310
 311         mutex_unlock(&led_cdev->led_access);
 312
 313         dev_dbg(parent, "Registered led device: %s\n",
 314                         led_cdev->name);
 315
 316         return 0;
 317 }
 318 EXPORT_SYMBOL_GPL(led_classdev_register_ext);
 319
 320 /**
 321  * led_classdev_unregister - unregisters a object of led_properties class.
 322  * @led_cdev: the led device to unregister
 323  *
 324  * Unregisters a previously registered via led_classdev_register object.
 325  */
 326 void led_classdev_unregister(struct led_classdev *led_cdev)
 327 {
 328 #ifdef CONFIG_LEDS_TRIGGERS
 329         down_write(&led_cdev->trigger_lock);
 330         if (led_cdev->trigger)
 331                 led_trigger_set(led_cdev, NULL);
 332         up_write(&led_cdev->trigger_lock);
 333 #endif
 334
 335         led_cdev->flags |= LED_UNREGISTERING;
 336
 337         /* Stop blinking */
 338         led_stop_software_blink(led_cdev);
 339
 340         led_set_brightness(led_cdev, LED_OFF);
 341
 342         flush_work(&led_cdev->set_brightness_work);
 343
 344         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
 345                 led_remove_brightness_hw_changed(led_cdev);
 346
 347         device_unregister(led_cdev->dev);
 348
 349         down_write(&leds_list_lock);
 350         list_del(&led_cdev->node);
 351         up_write(&leds_list_lock);
 352
 353         mutex_destroy(&led_cdev->led_access);
 354 }
 355 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 356
 357 static void devm_led_classdev_release(struct device *dev, void *res)
 358 {
 359         led_classdev_unregister(*(struct led_classdev **)res);
 360 }
 361
 362 /**
 363  * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
 364  *
 365  * @parent: parent of LED device
 366  * @led_cdev: the led_classdev structure for this device.
 367  * @init_data: LED class device initialization data
 368  */
 369 int devm_led_classdev_register_ext(struct device *parent,
 370                                    struct led_classdev *led_cdev,
 371                                    struct led_init_data *init_data)
 372 {
 373         struct led_classdev **dr;
 374         int rc;
 375
 376         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 377         if (!dr)
 378                 return -ENOMEM;
 379
 380         rc = led_classdev_register_ext(parent, led_cdev, init_data);
 381         if (rc) {
 382                 devres_free(dr);
 383                 return rc;
 384         }
 385
 386         *dr = led_cdev;
 387         devres_add(parent, dr);
 388
 389         return 0;
 390 }
 391 EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);
 392
 393 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 394 {
 395         struct led_cdev **p = res;
 396
 397         if (WARN_ON(!p || !*p))
 398                 return 0;
 399
 400         return *p == data;
 401 }
 402
 403 /**
 404  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 405  * @parent: The device to unregister.
 406  * @led_cdev: the led_classdev structure for this device.
 407  */
 408 void devm_led_classdev_unregister(struct device *dev,
 409                                   struct led_classdev *led_cdev)
 410 {
 411         WARN_ON(devres_release(dev,
 412                                devm_led_classdev_release,
 413                                devm_led_classdev_match, led_cdev));
 414 }
 415 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 416
 417 static int __init leds_init(void)
 418 {
 419         leds_class = class_create(THIS_MODULE, "leds");
 420         if (IS_ERR(leds_class))
 421                 return PTR_ERR(leds_class);
 422         leds_class->pm = &leds_class_dev_pm_ops;
 423         leds_class->dev_groups = led_groups;
 424         return 0;
 425 }
 426
 427 static void __exit leds_exit(void)
 428 {
 429         class_destroy(leds_class);
 430 }
 431
 432 subsys_initcall(leds_init);
 433 module_exit(leds_exit);
 434
 435 MODULE_AUTHOR("John Lenz, Richard Purdie");
 436 MODULE_LICENSE("GPL");
 437 MODULE_DESCRIPTION("LED Class Interface");