/*

 *  Generic Backlight Driver

 *

 *  Copyright (c) 2004-2008 Richard Purdie

 *

 *  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/platform_device.h>

#include <linux/mutex.h>

#include <linux/fb.h>

#include <linux/backlight.h>

static int genericbl_intensity;

static struct backlight_device *generic_backlight_device;

static struct generic_bl_info *bl_machinfo;

/* Flag to signal when the battery is low */

#define GENERICBL_BATTLOW       BL_CORE_DRIVER1

static int genericbl_send_intensity(struct backlight_device *bd)

{

	int intensity = bd->props.brightness;

	if (bd->props.power != FB_BLANK_UNBLANK)

		intensity = 0;

	if (bd->props.state & BL_CORE_FBBLANK)

		intensity = 0;

	if (bd->props.state & BL_CORE_SUSPENDED)

		intensity = 0;

	if (bd->props.state & GENERICBL_BATTLOW)

		intensity &= bl_machinfo->limit_mask;

	bl_machinfo->set_bl_intensity(intensity);

	genericbl_intensity = intensity;

	if (bl_machinfo->kick_battery)

		bl_machinfo->kick_battery();

	return 0;

}

static int genericbl_get_intensity(struct backlight_device *bd)

{

	return genericbl_intensity;

}

/*

 * Called when the battery is low to limit the backlight intensity.

 * If limit==0 clear any limit, otherwise limit the intensity

 */

void corgibl_limit_intensity(int limit)

{

	struct backlight_device *bd = generic_backlight_device;

	mutex_lock(&bd->ops_lock);

	if (limit)

		bd->props.state |= GENERICBL_BATTLOW;

	else

		bd->props.state &= ~GENERICBL_BATTLOW;

	backlight_update_status(generic_backlight_device);

	mutex_unlock(&bd->ops_lock);

}

EXPORT_SYMBOL(corgibl_limit_intensity);

static struct backlight_ops genericbl_ops = {

	.options = BL_CORE_SUSPENDRESUME,

	.get_brightness = genericbl_get_intensity,

	.update_status  = genericbl_send_intensity,

};

static int genericbl_probe(struct platform_device *pdev)

{

	struct generic_bl_info *machinfo = pdev->dev.platform_data;

	const char *name = "generic-bl";

	struct backlight_device *bd;

	bl_machinfo = machinfo;

	if (!machinfo->limit_mask)

		machinfo->limit_mask = -1;

	if (machinfo->name)

		name = machinfo->name;

	bd = backlight_device_register (name,

		&pdev->dev, NULL, &genericbl_ops);

	if (IS_ERR (bd))

		return PTR_ERR (bd);

	platform_set_drvdata(pdev, bd);

	bd->props.max_brightness = machinfo->max_intensity;

	bd->props.power = FB_BLANK_UNBLANK;

	bd->props.brightness = machinfo->default_intensity;

	backlight_update_status(bd);

	generic_backlight_device = bd;

	printk("Generic Backlight Driver Initialized.\n");

	return 0;

}

static int genericbl_remove(struct platform_device *pdev)

{

	struct backlight_device *bd = platform_get_drvdata(pdev);

	bd->props.power = 0;

	bd->props.brightness = 0;

	backlight_update_status(bd);

	backlight_device_unregister(bd);

	printk("Generic Backlight Driver Unloaded\n");

	return 0;

}

static struct platform_driver genericbl_driver = {

	.probe		= genericbl_probe,

	.remove		= genericbl_remove,

	.driver		= {

		.name	= "generic-bl",

	},

};

static int __init genericbl_init(void)

{

	return platform_driver_register(&genericbl_driver);

}

static void __exit genericbl_exit(void)

{

	platform_driver_unregister(&genericbl_driver);

}

module_init(genericbl_init);

module_exit(genericbl_exit);

MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");

MODULE_DESCRIPTION("Generic Backlight Driver");

MODULE_LICENSE("GPL");