/*
 * LED Kernel Timer Trigger
 *
 * Copyright 2005-2006 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/jiffies.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/ctype.h>
#include <linux/leds.h>
#include "leds.h"

struct timer_trig_data {
        int brightness_on;              /* LED brightness during "on" period.
                                         * (LED_OFF < brightness_on <= LED_FULL)
                                         */
        unsigned long delay_on;         /* milliseconds on */
        unsigned long delay_off;        /* milliseconds off */
        struct timer_list timer;
};

static void led_timer_function(unsigned long data)
{
        struct led_classdev *led_cdev = (struct led_classdev *) data;
        struct timer_trig_data *timer_data = led_cdev->trigger_data;
        unsigned long brightness;
        unsigned long delay;

        if (!timer_data->delay_on || !timer_data->delay_off) {
                led_set_brightness(led_cdev, LED_OFF);
                return;
        }

        brightness = led_get_brightness(led_cdev);
        if (!brightness) {
                /* Time to switch the LED on. */
                brightness = timer_data->brightness_on;
                delay = timer_data->delay_on;
        } else {
                /* Store the current brightness value to be able
                 * to restore it when the delay_off period is over.
                 */
                timer_data->brightness_on = brightness;
                brightness = LED_OFF;
                delay = timer_data->delay_off;
        }

        led_set_brightness(led_cdev, brightness);

        mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
}

static ssize_t led_delay_on_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct timer_trig_data *timer_data = led_cdev->trigger_data;

        return sprintf(buf, "%lu\n", timer_data->delay_on);
}

static ssize_t led_delay_on_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t size)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct timer_trig_data *timer_data = led_cdev->trigger_data;
        int ret = -EINVAL;
        char *after;
        unsigned long state = simple_strtoul(buf, &after, 10);
        size_t count = after - buf;

        if (*after && isspace(*after))
                count++;

        if (count == size) {
                if (timer_data->delay_on != state) {
                        /* the new value differs from the previous */
                        timer_data->delay_on = state;

                        /* deactivate previous settings */
                        del_timer_sync(&timer_data->timer);

                        /* try to activate hardware acceleration, if any */
                        if (!led_cdev->blink_set ||
                            led_cdev->blink_set(led_cdev,
                              &timer_data->delay_on, &timer_data->delay_off)) {
                                /* no hardware acceleration, blink via timer */
                                mod_timer(&timer_data->timer, jiffies + 1);
                        }
                }
                ret = count;
        }

        return ret;
}

static ssize_t led_delay_off_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct timer_trig_data *timer_data = led_cdev->trigger_data;

        return sprintf(buf, "%lu\n", timer_data->delay_off);
}

static ssize_t led_delay_off_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t size)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct timer_trig_data *timer_data = led_cdev->trigger_data;
        int ret = -EINVAL;
        char *after;
        unsigned long state = simple_strtoul(buf, &after, 10);
        size_t count = after - buf;

        if (*after && isspace(*after))
                count++;

        if (count == size) {
                if (timer_data->delay_off != state) {
                        /* the new value differs from the previous */
                        timer_data->delay_off = state;

                        /* deactivate previous settings */
                        del_timer_sync(&timer_data->timer);

                        /* try to activate hardware acceleration, if any */
                        if (!led_cdev->blink_set ||
                            led_cdev->blink_set(led_cdev,
                              &timer_data->delay_on, &timer_data->delay_off)) {
                                /* no hardware acceleration, blink via timer */
                                mod_timer(&timer_data->timer, jiffies + 1);
                        }
                }
                ret = count;
        }

        return ret;
}

static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);

static void timer_trig_activate(struct led_classdev *led_cdev)
{
        struct timer_trig_data *timer_data;
        int rc;

        timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
        if (!timer_data)
                return;

        timer_data->brightness_on = led_get_brightness(led_cdev);
        if (timer_data->brightness_on == LED_OFF)
                timer_data->brightness_on = led_cdev->max_brightness;
        led_cdev->trigger_data = timer_data;

        init_timer(&timer_data->timer);
        timer_data->timer.function = led_timer_function;
        timer_data->timer.data = (unsigned long) led_cdev;

        rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
        if (rc)
                goto err_out;
        rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
        if (rc)
                goto err_out_delayon;

        /* If there is hardware support for blinking, start one
         * user friendly blink rate chosen by the driver.
         */
        if (led_cdev->blink_set)
                led_cdev->blink_set(led_cdev,
                        &timer_data->delay_on, &timer_data->delay_off);

        return;

err_out_delayon:
        device_remove_file(led_cdev->dev, &dev_attr_delay_on);
err_out:
        led_cdev->trigger_data = NULL;
        kfree(timer_data);
}

static void timer_trig_deactivate(struct led_classdev *led_cdev)
{
        struct timer_trig_data *timer_data = led_cdev->trigger_data;
        unsigned long on = 0, off = 0;

        if (timer_data) {
                device_remove_file(led_cdev->dev, &dev_attr_delay_on);
                device_remove_file(led_cdev->dev, &dev_attr_delay_off);
                del_timer_sync(&timer_data->timer);
                kfree(timer_data);
        }

        /* If there is hardware support for blinking, stop it */
        if (led_cdev->blink_set)
                led_cdev->blink_set(led_cdev, &on, &off);
}

static struct led_trigger timer_led_trigger = {
        .name     = "timer",
        .activate = timer_trig_activate,
        .deactivate = timer_trig_deactivate,
};

static int __init timer_trig_init(void)
{
        return led_trigger_register(&timer_led_trigger);
}

static void __exit timer_trig_exit(void)
{
        led_trigger_unregister(&timer_led_trigger);
}

module_init(timer_trig_init);
module_exit(timer_trig_exit);

MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
MODULE_DESCRIPTION("Timer LED trigger");
MODULE_LICENSE("GPL");