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/*

 * 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");