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 "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
  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 static void led_timer_function(unsigned long data)
 106 {
 107         struct led_classdev *led_cdev = (void *)data;
 108         unsigned long brightness;
 109         unsigned long delay;
 110
 111         if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
 112                 led_set_brightness_async(led_cdev, LED_OFF);
 113                 return;
 114         }
 115
 116         if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) {
 117                 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
 118                 return;
 119         }
 120
 121         brightness = led_get_brightness(led_cdev);
 122         if (!brightness) {
 123                 /* Time to switch the LED on. */
 124                 if (led_cdev->delayed_set_value) {
 125                         led_cdev->blink_brightness =
 126                                         led_cdev->delayed_set_value;
 127                         led_cdev->delayed_set_value = 0;
 128                 }
 129                 brightness = led_cdev->blink_brightness;
 130                 delay = led_cdev->blink_delay_on;
 131         } else {
 132                 /* Store the current brightness value to be able
 133                  * to restore it when the delay_off period is over.
 134                  */
 135                 led_cdev->blink_brightness = brightness;
 136                 brightness = LED_OFF;
 137                 delay = led_cdev->blink_delay_off;
 138         }
 139
 140         led_set_brightness_async(led_cdev, brightness);
 141
 142         /* Return in next iteration if led is in one-shot mode and we are in
 143          * the final blink state so that the led is toggled each delay_on +
 144          * delay_off milliseconds in worst case.
 145          */
 146         if (led_cdev->flags & LED_BLINK_ONESHOT) {
 147                 if (led_cdev->flags & LED_BLINK_INVERT) {
 148                         if (brightness)
 149                                 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
 150                 } else {
 151                         if (!brightness)
 152                                 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
 153                 }
 154         }
 155
 156         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 157 }
 158
 159 static void set_brightness_delayed(struct work_struct *ws)
 160 {
 161         struct led_classdev *led_cdev =
 162                 container_of(ws, struct led_classdev, set_brightness_work);
 163
 164         led_stop_software_blink(led_cdev);
 165
 166         led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
 167 }
 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_cdev->brightness_set(led_cdev, 0);
 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_cdev->brightness_set(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 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
 215 static const struct dev_pm_ops leds_class_dev_pm_ops = {
 216         .suspend        = led_suspend,
 217         .resume         = led_resume,
 218 };
 219
 220 static int match_name(struct device *dev, const void *data)
 221 {
 222         if (!dev_name(dev))
 223                 return 0;
 224         return !strcmp(dev_name(dev), (char *)data);
 225 }
 226
 227 static int led_classdev_next_name(const char *init_name, char *name,
 228                                   size_t len)
 229 {
 230         unsigned int i = 0;
 231         int ret = 0;
 232
 233         strlcpy(name, init_name, len);
 234
 235         while (class_find_device(leds_class, NULL, name, match_name) &&
 236                (ret < len))
 237                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 238
 239         if (ret >= len)
 240                 return -ENOMEM;
 241
 242         return i;
 243 }
 244
 245 /**
 246  * led_classdev_register - register a new object of led_classdev class.
 247  * @parent: The device to register.
 248  * @led_cdev: the led_classdev structure for this device.
 249  */
 250 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 251 {
 252         char name[64];
 253         int ret;
 254
 255         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 256         if (ret < 0)
 257                 return ret;
 258
 259         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 260                                 led_cdev, led_cdev->groups, "%s", name);
 261         if (IS_ERR(led_cdev->dev))
 262                 return PTR_ERR(led_cdev->dev);
 263
 264         if (ret)
 265                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 266                                 led_cdev->name, dev_name(led_cdev->dev));
 267
 268 #ifdef CONFIG_LEDS_TRIGGERS
 269         init_rwsem(&led_cdev->trigger_lock);
 270 #endif
 271         mutex_init(&led_cdev->led_access);
 272         /* add to the list of leds */
 273         down_write(&leds_list_lock);
 274         list_add_tail(&led_cdev->node, &leds_list);
 275         up_write(&leds_list_lock);
 276
 277         if (!led_cdev->max_brightness)
 278                 led_cdev->max_brightness = LED_FULL;
 279
 280         led_cdev->flags |= SET_BRIGHTNESS_ASYNC;
 281
 282         led_update_brightness(led_cdev);
 283
 284         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 285
 286         setup_timer(&led_cdev->blink_timer, led_timer_function,
 287                     (unsigned long)led_cdev);
 288
 289 #ifdef CONFIG_LEDS_TRIGGERS
 290         led_trigger_set_default(led_cdev);
 291 #endif
 292
 293         dev_dbg(parent, "Registered led device: %s\n",
 294                         led_cdev->name);
 295
 296         return 0;
 297 }
 298 EXPORT_SYMBOL_GPL(led_classdev_register);
 299
 300 /**
 301  * led_classdev_unregister - unregisters a object of led_properties class.
 302  * @led_cdev: the led device to unregister
 303  *
 304  * Unregisters a previously registered via led_classdev_register object.
 305  */
 306 void led_classdev_unregister(struct led_classdev *led_cdev)
 307 {
 308 #ifdef CONFIG_LEDS_TRIGGERS
 309         down_write(&led_cdev->trigger_lock);
 310         if (led_cdev->trigger)
 311                 led_trigger_set(led_cdev, NULL);
 312         up_write(&led_cdev->trigger_lock);
 313 #endif
 314
 315         cancel_work_sync(&led_cdev->set_brightness_work);
 316
 317         /* Stop blinking */
 318         led_stop_software_blink(led_cdev);
 319         led_set_brightness(led_cdev, LED_OFF);
 320
 321         device_unregister(led_cdev->dev);
 322
 323         down_write(&leds_list_lock);
 324         list_del(&led_cdev->node);
 325         up_write(&leds_list_lock);
 326
 327         mutex_destroy(&led_cdev->led_access);
 328 }
 329 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 330
 331 static void devm_led_classdev_release(struct device *dev, void *res)
 332 {
 333         led_classdev_unregister(*(struct led_classdev **)res);
 334 }
 335
 336 /**
 337  * devm_led_classdev_register - resource managed led_classdev_register()
 338  * @parent: The device to register.
 339  * @led_cdev: the led_classdev structure for this device.
 340  */
 341 int devm_led_classdev_register(struct device *parent,
 342                                struct led_classdev *led_cdev)
 343 {
 344         struct led_classdev **dr;
 345         int rc;
 346
 347         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 348         if (!dr)
 349                 return -ENOMEM;
 350
 351         rc = led_classdev_register(parent, led_cdev);
 352         if (rc) {
 353                 devres_free(dr);
 354                 return rc;
 355         }
 356
 357         *dr = led_cdev;
 358         devres_add(parent, dr);
 359
 360         return 0;
 361 }
 362 EXPORT_SYMBOL_GPL(devm_led_classdev_register);
 363
 364 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 365 {
 366         struct led_cdev **p = res;
 367
 368         if (WARN_ON(!p || !*p))
 369                 return 0;
 370
 371         return *p == data;
 372 }
 373
 374 /**
 375  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 376  * @parent: The device to unregister.
 377  * @led_cdev: the led_classdev structure for this device.
 378  */
 379 void devm_led_classdev_unregister(struct device *dev,
 380                                   struct led_classdev *led_cdev)
 381 {
 382         WARN_ON(devres_release(dev,
 383                                devm_led_classdev_release,
 384                                devm_led_classdev_match, led_cdev));
 385 }
 386 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 387
 388 static int __init leds_init(void)
 389 {
 390         leds_class = class_create(THIS_MODULE, "leds");
 391         if (IS_ERR(leds_class))
 392                 return PTR_ERR(leds_class);
 393         leds_class->pm = &leds_class_dev_pm_ops;
 394         leds_class->dev_groups = led_groups;
 395         return 0;
 396 }
 397
 398 static void __exit leds_exit(void)
 399 {
 400         class_destroy(leds_class);
 401 }
 402
 403 subsys_initcall(leds_init);
 404 module_exit(leds_exit);
 405
 406 MODULE_AUTHOR("John Lenz, Richard Purdie");
 407 MODULE_LICENSE("GPL");
 408 MODULE_DESCRIPTION("LED Class Interface");