/*
 * LED Class Core
 *
 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
 * Copyright (C) 2005-2007 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/timer.h>
#include <linux/err.h>
#include <linux/ctype.h>
#include <linux/leds.h>
#include "leds.h"

static struct class *leds_class;

static void led_update_brightness(struct led_classdev *led_cdev)
{
        if (led_cdev->brightness_get)
                led_cdev->brightness = led_cdev->brightness_get(led_cdev);
}

static ssize_t brightness_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);

        /* no lock needed for this */
        led_update_brightness(led_cdev);

        return sprintf(buf, "%u\n", led_cdev->brightness);
}

static ssize_t brightness_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t size)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        unsigned long state;
        ssize_t ret = -EINVAL;

        ret = kstrtoul(buf, 10, &state);
        if (ret)
                return ret;

        if (state == LED_OFF)
                led_trigger_remove(led_cdev);
        __led_set_brightness(led_cdev, state);

        return size;
}
static DEVICE_ATTR_RW(brightness);

static ssize_t led_max_brightness_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);

        return sprintf(buf, "%u\n", led_cdev->max_brightness);
}
static DEVICE_ATTR(max_brightness, 0444, led_max_brightness_show, NULL);

#ifdef CONFIG_LEDS_TRIGGERS
static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
static struct attribute *led_trigger_attrs[] = {
        &dev_attr_trigger.attr,
        NULL,
};
static const struct attribute_group led_trigger_group = {
        .attrs = led_trigger_attrs,
};
#endif

static struct attribute *led_class_attrs[] = {
        &dev_attr_brightness.attr,
        &dev_attr_max_brightness.attr,
        NULL,
};

static const struct attribute_group led_group = {
        .attrs = led_class_attrs,
};

static const struct attribute_group *led_groups[] = {
        &led_group,
#ifdef CONFIG_LEDS_TRIGGERS
        &led_trigger_group,
#endif
        NULL,
};

static void led_timer_function(unsigned long data)
{
        struct led_classdev *led_cdev = (void *)data;
        unsigned long brightness;
        unsigned long delay;

        if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
                __led_set_brightness(led_cdev, LED_OFF);
                return;
        }

        if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) {
                led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP;
                return;
        }

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

        __led_set_brightness(led_cdev, brightness);

        /* Return in next iteration if led is in one-shot mode and we are in
         * the final blink state so that the led is toggled each delay_on +
         * delay_off milliseconds in worst case.
         */
        if (led_cdev->flags & LED_BLINK_ONESHOT) {
                if (led_cdev->flags & LED_BLINK_INVERT) {
                        if (brightness)
                                led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
                } else {
                        if (!brightness)
                                led_cdev->flags |= LED_BLINK_ONESHOT_STOP;
                }
        }

        mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
}

static void set_brightness_delayed(struct work_struct *ws)
{
        struct led_classdev *led_cdev =
                container_of(ws, struct led_classdev, set_brightness_work);

        led_stop_software_blink(led_cdev);

        __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
}

/**
 * led_classdev_suspend - suspend an led_classdev.
 * @led_cdev: the led_classdev to suspend.
 */
void led_classdev_suspend(struct led_classdev *led_cdev)
{
        led_cdev->flags |= LED_SUSPENDED;
        led_cdev->brightness_set(led_cdev, 0);
}
EXPORT_SYMBOL_GPL(led_classdev_suspend);

/**
 * led_classdev_resume - resume an led_classdev.
 * @led_cdev: the led_classdev to resume.
 */
void led_classdev_resume(struct led_classdev *led_cdev)
{
        led_cdev->brightness_set(led_cdev, led_cdev->brightness);
        led_cdev->flags &= ~LED_SUSPENDED;
}
EXPORT_SYMBOL_GPL(led_classdev_resume);

static int led_suspend(struct device *dev)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);

        if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
                led_classdev_suspend(led_cdev);

        return 0;
}

static int led_resume(struct device *dev)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);

        if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
                led_classdev_resume(led_cdev);

        return 0;
}

static const struct dev_pm_ops leds_class_dev_pm_ops = {
        .suspend        = led_suspend,
        .resume         = led_resume,
};

/**
 * led_classdev_register - register a new object of led_classdev class.
 * @parent: The device to register.
 * @led_cdev: the led_classdev structure for this device.
 */
int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
{
        led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
                                      "%s", led_cdev->name);
        if (IS_ERR(led_cdev->dev))
                return PTR_ERR(led_cdev->dev);

#ifdef CONFIG_LEDS_TRIGGERS
        init_rwsem(&led_cdev->trigger_lock);
#endif
        /* add to the list of leds */
        down_write(&leds_list_lock);
        list_add_tail(&led_cdev->node, &leds_list);
        up_write(&leds_list_lock);

        if (!led_cdev->max_brightness)
                led_cdev->max_brightness = LED_FULL;

        led_update_brightness(led_cdev);

        INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);

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

#ifdef CONFIG_LEDS_TRIGGERS
        led_trigger_set_default(led_cdev);
#endif

        dev_dbg(parent, "Registered led device: %s\n",
                        led_cdev->name);

        return 0;
}
EXPORT_SYMBOL_GPL(led_classdev_register);

/**
 * led_classdev_unregister - unregisters a object of led_properties class.
 * @led_cdev: the led device to unregister
 *
 * Unregisters a previously registered via led_classdev_register object.
 */
void led_classdev_unregister(struct led_classdev *led_cdev)
{
#ifdef CONFIG_LEDS_TRIGGERS
        down_write(&led_cdev->trigger_lock);
        if (led_cdev->trigger)
                led_trigger_set(led_cdev, NULL);
        up_write(&led_cdev->trigger_lock);
#endif

        cancel_work_sync(&led_cdev->set_brightness_work);

        /* Stop blinking */
        led_stop_software_blink(led_cdev);
        led_set_brightness(led_cdev, LED_OFF);

        device_unregister(led_cdev->dev);

        down_write(&leds_list_lock);
        list_del(&led_cdev->node);
        up_write(&leds_list_lock);
}
EXPORT_SYMBOL_GPL(led_classdev_unregister);

static int __init leds_init(void)
{
        leds_class = class_create(THIS_MODULE, "leds");
        if (IS_ERR(leds_class))
                return PTR_ERR(leds_class);
        leds_class->pm = &leds_class_dev_pm_ops;
        leds_class->dev_groups = led_groups;
        return 0;
}

static void __exit leds_exit(void)
{
        class_destroy(leds_class);
}

subsys_initcall(leds_init);
module_exit(leds_exit);

MODULE_AUTHOR("John Lenz, Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Class Interface");