Logo Search packages:      
Sourcecode: linux version File versions  Download package

led-triggers.c

/*
 * LED Triggers Core
 *
 * Copyright 2005-2007 Openedhand Ltd.
 *
 * Author: Richard Purdie <rpurdie@openedhand.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/sysdev.h>
#include <linux/timer.h>
#include <linux/rwsem.h>
#include <linux/leds.h>
#include "leds.h"

/*
 * Nests outside led_cdev->trigger_lock
 */
static DECLARE_RWSEM(triggers_list_lock);
static LIST_HEAD(trigger_list);

ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
      struct led_classdev *led_cdev = dev_get_drvdata(dev);
      char trigger_name[TRIG_NAME_MAX];
      struct led_trigger *trig;
      size_t len;

      trigger_name[sizeof(trigger_name) - 1] = '\0';
      strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
      len = strlen(trigger_name);

      if (len && trigger_name[len - 1] == '\n')
            trigger_name[len - 1] = '\0';

      if (!strcmp(trigger_name, "none")) {
            down_write(&led_cdev->trigger_lock);
            led_trigger_set(led_cdev, NULL);
            up_write(&led_cdev->trigger_lock);
            return count;
      }

      down_read(&triggers_list_lock);
      list_for_each_entry(trig, &trigger_list, next_trig) {
            if (!strcmp(trigger_name, trig->name)) {
                  down_write(&led_cdev->trigger_lock);
                  led_trigger_set(led_cdev, trig);
                  up_write(&led_cdev->trigger_lock);

                  up_read(&triggers_list_lock);
                  return count;
            }
      }
      up_read(&triggers_list_lock);

      return -EINVAL;
}


ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
            char *buf)
{
      struct led_classdev *led_cdev = dev_get_drvdata(dev);
      struct led_trigger *trig;
      int len = 0;

      down_read(&triggers_list_lock);
      down_read(&led_cdev->trigger_lock);

      if (!led_cdev->trigger)
            len += sprintf(buf+len, "[none] ");
      else
            len += sprintf(buf+len, "none ");

      list_for_each_entry(trig, &trigger_list, next_trig) {
            if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
                                          trig->name))
                  len += sprintf(buf+len, "[%s] ", trig->name);
            else
                  len += sprintf(buf+len, "%s ", trig->name);
      }
      up_read(&led_cdev->trigger_lock);
      up_read(&triggers_list_lock);

      len += sprintf(len+buf, "\n");
      return len;
}

void led_trigger_event(struct led_trigger *trigger,
                  enum led_brightness brightness)
{
      struct list_head *entry;

      if (!trigger)
            return;

      read_lock(&trigger->leddev_list_lock);
      list_for_each(entry, &trigger->led_cdevs) {
            struct led_classdev *led_cdev;

            led_cdev = list_entry(entry, struct led_classdev, trig_list);
            led_set_brightness(led_cdev, brightness);
      }
      read_unlock(&trigger->leddev_list_lock);
}

/* Caller must ensure led_cdev->trigger_lock held */
void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger)
{
      unsigned long flags;

      /* Remove any existing trigger */
      if (led_cdev->trigger) {
            write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
            list_del(&led_cdev->trig_list);
            write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
            if (led_cdev->trigger->deactivate)
                  led_cdev->trigger->deactivate(led_cdev);
            led_set_brightness(led_cdev, LED_OFF);
      }
      if (trigger) {
            write_lock_irqsave(&trigger->leddev_list_lock, flags);
            list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs);
            write_unlock_irqrestore(&trigger->leddev_list_lock, flags);
            if (trigger->activate)
                  trigger->activate(led_cdev);
      }
      led_cdev->trigger = trigger;
}

void led_trigger_set_default(struct led_classdev *led_cdev)
{
      struct led_trigger *trig;

      if (!led_cdev->default_trigger)
            return;

      down_read(&triggers_list_lock);
      down_write(&led_cdev->trigger_lock);
      list_for_each_entry(trig, &trigger_list, next_trig) {
            if (!strcmp(led_cdev->default_trigger, trig->name))
                  led_trigger_set(led_cdev, trig);
      }
      up_write(&led_cdev->trigger_lock);
      up_read(&triggers_list_lock);
}

int led_trigger_register(struct led_trigger *trigger)
{
      struct led_classdev *led_cdev;

      rwlock_init(&trigger->leddev_list_lock);
      INIT_LIST_HEAD(&trigger->led_cdevs);

      /* Add to the list of led triggers */
      down_write(&triggers_list_lock);
      list_add_tail(&trigger->next_trig, &trigger_list);
      up_write(&triggers_list_lock);

      /* Register with any LEDs that have this as a default trigger */
      down_read(&leds_list_lock);
      list_for_each_entry(led_cdev, &leds_list, node) {
            down_write(&led_cdev->trigger_lock);
            if (!led_cdev->trigger && led_cdev->default_trigger &&
                      !strcmp(led_cdev->default_trigger, trigger->name))
                  led_trigger_set(led_cdev, trigger);
            up_write(&led_cdev->trigger_lock);
      }
      up_read(&leds_list_lock);

      return 0;
}

void led_trigger_register_simple(const char *name, struct led_trigger **tp)
{
      struct led_trigger *trigger;
      int err;

      trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);

      if (trigger) {
            trigger->name = name;
            err = led_trigger_register(trigger);
            if (err < 0)
                  printk(KERN_WARNING "LED trigger %s failed to register"
                        " (%d)\n", name, err);
      } else
            printk(KERN_WARNING "LED trigger %s failed to register"
                  " (no memory)\n", name);

      *tp = trigger;
}

void led_trigger_unregister(struct led_trigger *trigger)
{
      struct led_classdev *led_cdev;

      /* Remove from the list of led triggers */
      down_write(&triggers_list_lock);
      list_del(&trigger->next_trig);
      up_write(&triggers_list_lock);

      /* Remove anyone actively using this trigger */
      down_read(&leds_list_lock);
      list_for_each_entry(led_cdev, &leds_list, node) {
            down_write(&led_cdev->trigger_lock);
            if (led_cdev->trigger == trigger)
                  led_trigger_set(led_cdev, NULL);
            up_write(&led_cdev->trigger_lock);
      }
      up_read(&leds_list_lock);
}

void led_trigger_unregister_simple(struct led_trigger *trigger)
{
      if (trigger)
            led_trigger_unregister(trigger);
      kfree(trigger);
}

/* Used by LED Class */
EXPORT_SYMBOL_GPL(led_trigger_set);
EXPORT_SYMBOL_GPL(led_trigger_set_default);
EXPORT_SYMBOL_GPL(led_trigger_show);
EXPORT_SYMBOL_GPL(led_trigger_store);

/* LED Trigger Interface */
EXPORT_SYMBOL_GPL(led_trigger_register);
EXPORT_SYMBOL_GPL(led_trigger_unregister);

/* Simple LED Tigger Interface */
EXPORT_SYMBOL_GPL(led_trigger_register_simple);
EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
EXPORT_SYMBOL_GPL(led_trigger_event);

MODULE_AUTHOR("Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Triggers Core");

Generated by  Doxygen 1.6.0   Back to index