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/*
* 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 genericbl_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(genericbl_limit_intensity);
static const 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 backlight_properties props;
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;
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_RAW;
props.max_brightness = machinfo->max_intensity;
bd = backlight_device_register(name, &pdev->dev, NULL, &genericbl_ops,
&props);
if (IS_ERR (bd))
return PTR_ERR (bd);
platform_set_drvdata(pdev, bd);
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");
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