drivers/leds/led-class.c

   1 /*
   2  * LED Class Core
   3  *
   4  * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
   5  * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/ctype.h>
  13 #include <linux/device.h>
  14 #include <linux/err.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/leds.h>
  18 #include <linux/list.h>
  19 #include <linux/module.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/timer.h>
  23 #include <uapi/linux/uleds.h>
  24 #include "leds.h"
  25
  26 static struct class *leds_class;
  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
  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 DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  79 static struct attribute *led_trigger_attrs[] = {
  80         &dev_attr_trigger.attr,
  81         NULL,
  82 };
  83 static const struct attribute_group led_trigger_group = {
  84         .attrs = led_trigger_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 }
 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 static int match_name(struct device *dev, const void *data)
 219 {
 220         if (!dev_name(dev))
 221                 return 0;
 222         return !strcmp(dev_name(dev), (char *)data);
 223 }
 224
 225 static int led_classdev_next_name(const char *init_name, char *name,
 226                                   size_t len)
 227 {
 228         unsigned int i = 0;
 229         int ret = 0;
 230         struct device *dev;
 231
 232         strlcpy(name, init_name, len);
 233
 234         while ((ret < len) &&
 235                (dev = class_find_device(leds_class, NULL, name, match_name))) {
 236                 put_device(dev);
 237                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 238         }
 239
 240         if (ret >= len)
 241                 return -ENOMEM;
 242
 243         return i;
 244 }
 245
 246 /**
 247  * of_led_classdev_register - register a new object of led_classdev class.
 248  *
 249  * @parent: parent of LED device
 250  * @led_cdev: the led_classdev structure for this device.
 251  * @np: DT node describing this LED
 252  */
 253 int of_led_classdev_register(struct device *parent, struct device_node *np,
 254                             struct led_classdev *led_cdev)
 255 {
 256         char name[LED_MAX_NAME_SIZE];
 257         int ret;
 258
 259         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 260         if (ret < 0)
 261                 return ret;
 262
 263         mutex_init(&led_cdev->led_access);
 264         mutex_lock(&led_cdev->led_access);
 265         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 266                                 led_cdev, led_cdev->groups, "%s", name);
 267         if (IS_ERR(led_cdev->dev)) {
 268                 mutex_unlock(&led_cdev->led_access);
 269                 return PTR_ERR(led_cdev->dev);
 270         }
 271         led_cdev->dev->of_node = np;
 272
 273         if (ret)
 274                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 275                                 led_cdev->name, dev_name(led_cdev->dev));
 276
 277         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 278                 ret = led_add_brightness_hw_changed(led_cdev);
 279                 if (ret) {
 280                         device_unregister(led_cdev->dev);
 281                         mutex_unlock(&led_cdev->led_access);
 282                         return ret;
 283                 }
 284         }
 285
 286         led_cdev->work_flags = 0;
 287 #ifdef CONFIG_LEDS_TRIGGERS
 288         init_rwsem(&led_cdev->trigger_lock);
 289 #endif
 290 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 291         led_cdev->brightness_hw_changed = -1;
 292 #endif
 293         /* add to the list of leds */
 294         down_write(&leds_list_lock);
 295         list_add_tail(&led_cdev->node, &leds_list);
 296         up_write(&leds_list_lock);
 297
 298         if (!led_cdev->max_brightness)
 299                 led_cdev->max_brightness = LED_FULL;
 300
 301         led_update_brightness(led_cdev);
 302
 303         led_init_core(led_cdev);
 304
 305 #ifdef CONFIG_LEDS_TRIGGERS
 306         led_trigger_set_default(led_cdev);
 307 #endif
 308
 309         mutex_unlock(&led_cdev->led_access);
 310
 311         dev_dbg(parent, "Registered led device: %s\n",
 312                         led_cdev->name);
 313
 314         return 0;
 315 }
 316 EXPORT_SYMBOL_GPL(of_led_classdev_register);
 317
 318 /**
 319  * led_classdev_unregister - unregisters a object of led_properties class.
 320  * @led_cdev: the led device to unregister
 321  *
 322  * Unregisters a previously registered via led_classdev_register object.
 323  */
 324 void led_classdev_unregister(struct led_classdev *led_cdev)
 325 {
 326 #ifdef CONFIG_LEDS_TRIGGERS
 327         down_write(&led_cdev->trigger_lock);
 328         if (led_cdev->trigger)
 329                 led_trigger_set(led_cdev, NULL);
 330         up_write(&led_cdev->trigger_lock);
 331 #endif
 332
 333         led_cdev->flags |= LED_UNREGISTERING;
 334
 335         /* Stop blinking */
 336         led_stop_software_blink(led_cdev);
 337
 338         led_set_brightness(led_cdev, LED_OFF);
 339
 340         flush_work(&led_cdev->set_brightness_work);
 341
 342         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
 343                 led_remove_brightness_hw_changed(led_cdev);
 344
 345         device_unregister(led_cdev->dev);
 346
 347         down_write(&leds_list_lock);
 348         list_del(&led_cdev->node);
 349         up_write(&leds_list_lock);
 350
 351         mutex_destroy(&led_cdev->led_access);
 352 }
 353 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 354
 355 static void devm_led_classdev_release(struct device *dev, void *res)
 356 {
 357         led_classdev_unregister(*(struct led_classdev **)res);
 358 }
 359
 360 /**
 361  * devm_of_led_classdev_register - resource managed led_classdev_register()
 362  *
 363  * @parent: parent of LED device
 364  * @led_cdev: the led_classdev structure for this device.
 365  */
 366 int devm_of_led_classdev_register(struct device *parent,
 367                                   struct device_node *np,
 368                                   struct led_classdev *led_cdev)
 369 {
 370         struct led_classdev **dr;
 371         int rc;
 372
 373         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 374         if (!dr)
 375                 return -ENOMEM;
 376
 377         rc = of_led_classdev_register(parent, np, led_cdev);
 378         if (rc) {
 379                 devres_free(dr);
 380                 return rc;
 381         }
 382
 383         *dr = led_cdev;
 384         devres_add(parent, dr);
 385
 386         return 0;
 387 }
 388 EXPORT_SYMBOL_GPL(devm_of_led_classdev_register);
 389
 390 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 391 {
 392         struct led_cdev **p = res;
 393
 394         if (WARN_ON(!p || !*p))
 395                 return 0;
 396
 397         return *p == data;
 398 }
 399
 400 /**
 401  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 402  * @parent: The device to unregister.
 403  * @led_cdev: the led_classdev structure for this device.
 404  */
 405 void devm_led_classdev_unregister(struct device *dev,
 406                                   struct led_classdev *led_cdev)
 407 {
 408         WARN_ON(devres_release(dev,
 409                                devm_led_classdev_release,
 410                                devm_led_classdev_match, led_cdev));
 411 }
 412 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 413
 414 static int __init leds_init(void)
 415 {
 416         leds_class = class_create(THIS_MODULE, "leds");
 417         if (IS_ERR(leds_class))
 418                 return PTR_ERR(leds_class);
 419         leds_class->pm = &leds_class_dev_pm_ops;
 420         leds_class->dev_groups = led_groups;
 421         return 0;
 422 }
 423
 424 static void __exit leds_exit(void)
 425 {
 426         class_destroy(leds_class);
 427 }
 428
 429 subsys_initcall(leds_init);
 430 module_exit(leds_exit);
 431
 432 MODULE_AUTHOR("John Lenz, Richard Purdie");
 433 MODULE_LICENSE("GPL");
 434 MODULE_DESCRIPTION("LED Class Interface");