rockbox/firmware/backlight-sw-fading.c

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2008 by Thomas Martitz
* Copyright (C) 2008 by Martin Ritter
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stdbool.h>
#include "config.h"
#include "backlight-target.h"
#include "system.h"
#include "backlight.h"
#include "backlight-sw-fading.h"
#ifndef BRIGHTNESS_STEP
#define BRIGHTNESS_STEP 1
#endif
/* To adapt a target do:
* - make sure backlight_hw_on doesn't set the brightness to something other than
* the previous value (lowest brightness in most cases)
* add proper #defines for software fading
*/
/* can be MIN_BRIGHTNESS_SETTING-1 */
static int current_brightness = DEFAULT_BRIGHTNESS_SETTING;
void _backlight_fade_update_state(int brightness)
{
current_brightness = brightness;
}
/* returns true if fade is finished */
static bool _backlight_fade_up(void)
{
if (LIKELY(current_brightness < backlight_brightness))
{
#if BRIGHTNESS_STEP == 1
backlight_hw_brightness(++current_brightness);
#else
current_brightness += BRIGHTNESS_STEP;
if (current_brightness > MAX_BRIGHTNESS_SETTING)
current_brightness = MAX_BRIGHTNESS_SETTING;
backlight_hw_brightness(current_brightness);
#endif
}
return(current_brightness >= backlight_brightness);
}
/* returns true if fade is finished */
static bool _backlight_fade_down(void)
{
if (LIKELY(current_brightness > MIN_BRIGHTNESS_SETTING))
{
#if BRIGHTNESS_STEP == 1
backlight_hw_brightness(--current_brightness);
#else
current_brightness -= BRIGHTNESS_STEP;
if (current_brightness < MIN_BRIGHTNESS_SETTING)
current_brightness = MIN_BRIGHTNESS_SETTING;
backlight_hw_brightness(current_brightness);
#endif
return false;
}
else
{
/* decrement once more, since backlight is off */
#if BRIGHTNESS_STEP == 1
current_brightness--;
#else
current_brightness=MIN_BRIGHTNESS_SETTING -1;
#endif
backlight_hw_off();
return true;
}
}
bool _backlight_fade_step(int direction)
{
bool done;
switch(direction)
{
case FADING_UP:
done = _backlight_fade_up();
break;
case FADING_DOWN:
done = _backlight_fade_down();
break;
default:
done = true;
break;
}
return(done);
}