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/*
* Backlight emulation LED trigger
*
* Copyright 2008 (C) Rodolfo Giometti <giometti@linux.it>
* Copyright 2008 (C) Eurotech S.p.A. <info@eurotech.it>
*
* 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/slab.h>
#include <linux/init.h>
#include <linux/fb.h>
#include <linux/leds.h>
#include "leds.h"
#define BLANK 1
#define UNBLANK 0
struct bl_trig_notifier {
struct led_classdev *led;
int brightness;
int old_status;
struct notifier_block notifier;
};
static int fb_notifier_callback(struct notifier_block *p,
unsigned long event, void *data)
{
struct bl_trig_notifier *n = container_of(p,
struct bl_trig_notifier, notifier);
struct led_classdev *led = n->led;
struct fb_event *fb_event = data;
int *blank = fb_event->data;
switch (event) {
case FB_EVENT_BLANK :
if (*blank && n->old_status == UNBLANK) {
n->brightness = led->brightness;
led_set_brightness(led, LED_OFF);
n->old_status = BLANK;
} else if (!*blank && n->old_status == BLANK) {
led_set_brightness(led, n->brightness);
n->old_status = UNBLANK;
}
break;
}
return 0;
}
static void bl_trig_activate(struct led_classdev *led)
{
int ret;
struct bl_trig_notifier *n;
n = kzalloc(sizeof(struct bl_trig_notifier), GFP_KERNEL);
led->trigger_data = n;
if (!n) {
dev_err(led->dev, "unable to allocate backlight trigger\n");
return;
}
n->led = led;
n->brightness = led->brightness;
n->old_status = UNBLANK;
n->notifier.notifier_call = fb_notifier_callback;
ret = fb_register_client(&n->notifier);
if (ret)
dev_err(led->dev, "unable to register backlight trigger\n");
}
static void bl_trig_deactivate(struct led_classdev *led)
{
struct bl_trig_notifier *n =
(struct bl_trig_notifier *) led->trigger_data;
if (n) {
fb_unregister_client(&n->notifier);
kfree(n);
}
}
static struct led_trigger bl_led_trigger = {
.name = "backlight",
.activate = bl_trig_activate,
.deactivate = bl_trig_deactivate
};
static int __init bl_trig_init(void)
{
return led_trigger_register(&bl_led_trigger);
}
static void __exit bl_trig_exit(void)
{
led_trigger_unregister(&bl_led_trigger);
}
module_init(bl_trig_init);
module_exit(bl_trig_exit);
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
MODULE_DESCRIPTION("Backlight emulation LED trigger");
MODULE_LICENSE("GPL v2");
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