kernel/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                 brightness = led_cdev->blink_brightness;
 125                 delay = led_cdev->blink_delay_on;
 126         } else {
 127                 /* Store the current brightness value to be able
 128                  * to restore it when the delay_off period is over.
 129                  */
 130                 led_cdev->blink_brightness = brightness;
 131                 brightness = LED_OFF;
 132                 delay = led_cdev->blink_delay_off;
 133         }
 134
 135         led_set_brightness_async(led_cdev, brightness);
 136
 137         /* Return in next iteration if led is in one-shot mode and we are in
 138          * the final blink state so that the led is toggled each delay_on +
 139          * delay_off milliseconds in worst case.
 140          */
 141         if (led_cdev->flags & LED_BLINK_ONESHOT) {
 142                 if (led_cdev->flags & LED_BLINK_INVERT) {
 143                         if (brightness)
 144                                 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
 145                 } else {
 146                         if (!brightness)
 147                                 led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
 148                 }
 149         }
 150
 151         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 152 }
 153
 154 static void set_brightness_delayed(struct work_struct *ws)
 155 {
 156         struct led_classdev *led_cdev =
 157                 container_of(ws, struct led_classdev, set_brightness_work);
 158
 159         led_stop_software_blink(led_cdev);
 160
 161         led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
 162 }
 163
 164 /**
 165  * led_classdev_suspend - suspend an led_classdev.
 166  * @led_cdev: the led_classdev to suspend.
 167  */
 168 void led_classdev_suspend(struct led_classdev *led_cdev)
 169 {
 170         led_cdev->flags |= LED_SUSPENDED;
 171         led_cdev->brightness_set(led_cdev, 0);
 172 }
 173 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 174
 175 /**
 176  * led_classdev_resume - resume an led_classdev.
 177  * @led_cdev: the led_classdev to resume.
 178  */
 179 void led_classdev_resume(struct led_classdev *led_cdev)
 180 {
 181         led_cdev->brightness_set(led_cdev, led_cdev->brightness);
 182
 183         if (led_cdev->flash_resume)
 184                 led_cdev->flash_resume(led_cdev);
 185
 186         led_cdev->flags &= ~LED_SUSPENDED;
 187 }
 188 EXPORT_SYMBOL_GPL(led_classdev_resume);
 189
 190 #ifdef CONFIG_PM_SLEEP
 191 static int led_suspend(struct device *dev)
 192 {
 193         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 194
 195         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 196                 led_classdev_suspend(led_cdev);
 197
 198         return 0;
 199 }
 200
 201 static int led_resume(struct device *dev)
 202 {
 203         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 204
 205         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 206                 led_classdev_resume(led_cdev);
 207
 208         return 0;
 209 }
 210 #endif
 211
 212 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 213
 214 static int match_name(struct device *dev, const void *data)
 215 {
 216         if (!dev_name(dev))
 217                 return 0;
 218         return !strcmp(dev_name(dev), (char *)data);
 219 }
 220
 221 static int led_classdev_next_name(const char *init_name, char *name,
 222                                   size_t len)
 223 {
 224         unsigned int i = 0;
 225         int ret = 0;
 226
 227         strlcpy(name, init_name, len);
 228
 229         while (class_find_device(leds_class, NULL, name, match_name) &&
 230                (ret < len))
 231                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 232
 233         if (ret >= len)
 234                 return -ENOMEM;
 235
 236         return i;
 237 }
 238
 239 /**
 240  * led_classdev_register - register a new object of led_classdev class.
 241  * @parent: The device to register.
 242  * @led_cdev: the led_classdev structure for this device.
 243  */
 244 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
 245 {
 246         char name[64];
 247         int ret;
 248
 249         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 250         if (ret < 0)
 251                 return ret;
 252
 253         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 254                                 led_cdev, led_cdev->groups, "%s", name);
 255         if (IS_ERR(led_cdev->dev))
 256                 return PTR_ERR(led_cdev->dev);
 257
 258         if (ret)
 259                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 260                                 led_cdev->name, dev_name(led_cdev->dev));
 261
 262 #ifdef CONFIG_LEDS_TRIGGERS
 263         init_rwsem(&led_cdev->trigger_lock);
 264 #endif
 265         mutex_init(&led_cdev->led_access);
 266         /* add to the list of leds */
 267         down_write(&leds_list_lock);
 268         list_add_tail(&led_cdev->node, &leds_list);
 269         up_write(&leds_list_lock);
 270
 271         if (!led_cdev->max_brightness)
 272                 led_cdev->max_brightness = LED_FULL;
 273
 274         led_cdev->flags |= SET_BRIGHTNESS_ASYNC;
 275
 276         led_update_brightness(led_cdev);
 277
 278         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 279
 280         setup_timer(&led_cdev->blink_timer, led_timer_function,
 281                     (unsigned long)led_cdev);
 282
 283 #ifdef CONFIG_LEDS_TRIGGERS
 284         led_trigger_set_default(led_cdev);
 285 #endif
 286
 287         dev_dbg(parent, "Registered led device: %s\n",
 288                         led_cdev->name);
 289
 290         return 0;
 291 }
 292 EXPORT_SYMBOL_GPL(led_classdev_register);
 293
 294 /**
 295  * led_classdev_unregister - unregisters a object of led_properties class.
 296  * @led_cdev: the led device to unregister
 297  *
 298  * Unregisters a previously registered via led_classdev_register object.
 299  */
 300 void led_classdev_unregister(struct led_classdev *led_cdev)
 301 {
 302 #ifdef CONFIG_LEDS_TRIGGERS
 303         down_write(&led_cdev->trigger_lock);
 304         if (led_cdev->trigger)
 305                 led_trigger_set(led_cdev, NULL);
 306         up_write(&led_cdev->trigger_lock);
 307 #endif
 308
 309         cancel_work_sync(&led_cdev->set_brightness_work);
 310
 311         /* Stop blinking */
 312         led_stop_software_blink(led_cdev);
 313         led_set_brightness(led_cdev, LED_OFF);
 314
 315         device_unregister(led_cdev->dev);
 316
 317         down_write(&leds_list_lock);
 318         list_del(&led_cdev->node);
 319         up_write(&leds_list_lock);
 320
 321         mutex_destroy(&led_cdev->led_access);
 322 }
 323 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 324
 325 static void devm_led_classdev_release(struct device *dev, void *res)
 326 {
 327         led_classdev_unregister(*(struct led_classdev **)res);
 328 }
 329
 330 /**
 331  * devm_led_classdev_register - resource managed led_classdev_register()
 332  * @parent: The device to register.
 333  * @led_cdev: the led_classdev structure for this device.
 334  */
 335 int devm_led_classdev_register(struct device *parent,
 336                                struct led_classdev *led_cdev)
 337 {
 338         struct led_classdev **dr;
 339         int rc;
 340
 341         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 342         if (!dr)
 343                 return -ENOMEM;
 344
 345         rc = led_classdev_register(parent, led_cdev);
 346         if (rc) {
 347                 devres_free(dr);
 348                 return rc;
 349         }
 350
 351         *dr = led_cdev;
 352         devres_add(parent, dr);
 353
 354         return 0;
 355 }
 356 EXPORT_SYMBOL_GPL(devm_led_classdev_register);
 357
 358 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 359 {
 360         struct led_cdev **p = res;
 361
 362         if (WARN_ON(!p || !*p))
 363                 return 0;
 364
 365         return *p == data;
 366 }
 367
 368 /**
 369  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 370  * @parent: The device to unregister.
 371  * @led_cdev: the led_classdev structure for this device.
 372  */
 373 void devm_led_classdev_unregister(struct device *dev,
 374                                   struct led_classdev *led_cdev)
 375 {
 376         WARN_ON(devres_release(dev,
 377                                devm_led_classdev_release,
 378                                devm_led_classdev_match, led_cdev));
 379 }
 380 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 381
 382 static int __init leds_init(void)
 383 {
 384         leds_class = class_create(THIS_MODULE, "leds");
 385         if (IS_ERR(leds_class))
 386                 return PTR_ERR(leds_class);
 387         leds_class->pm = &leds_class_dev_pm_ops;
 388         leds_class->dev_groups = led_groups;
 389         return 0;
 390 }
 391
 392 static void __exit leds_exit(void)
 393 {
 394         class_destroy(leds_class);
 395 }
 396
 397 subsys_initcall(leds_init);
 398 module_exit(leds_exit);
 399
 400 MODULE_AUTHOR("John Lenz, Richard Purdie");
 401 MODULE_LICENSE("GPL");
 402 MODULE_DESCRIPTION("LED Class Interface");