firmware/backlight-sw-fading.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2008 by Thomas Martitz
  11  * Copyright (C) 2008 by Martin Ritter
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19  * KIND, either express or implied.
  20  *
  21  ****************************************************************************/
  22
  23 #include <stdbool.h>
  24 #include "backlight-target.h"
  25 #include "config.h"
  26 #include "system.h"
  27 #include "backlight.h"
  28 #include "backlight-sw-fading.h"
  29
  30 /* To adapt a target do:
  31  * - make sure _backlight_on doesn't set the brightness to something other than
  32  *  the previous value (lowest brightness in most cases)
  33  * add proper #defines for software fading
  34  */
  35
  36 /* can be MIN_BRIGHTNESS_SETTING-1 */
  37 static int current_brightness = DEFAULT_BRIGHTNESS_SETTING;
  38
  39 void _backlight_fade_update_state(int brightness)
  40 {
  41     current_brightness = brightness;
  42 }
  43
  44 /* returns true if fade is finished */
  45 static bool _backlight_fade_up(void)
  46 {
  47     if (LIKELY(current_brightness < backlight_brightness))
  48     {
  49         _backlight_set_brightness(++current_brightness);
  50     }
  51     return(current_brightness >= backlight_brightness);
  52 }
  53
  54 /* returns true if fade is finished */
  55 static bool _backlight_fade_down(void)
  56 {
  57     if (LIKELY(current_brightness > MIN_BRIGHTNESS_SETTING))
  58     {
  59         _backlight_set_brightness(--current_brightness);
  60         return false;
  61     }
  62     else
  63     {
  64         /* decrement once more, since backlight is off */
  65         current_brightness--;
  66         _backlight_off();
  67         return true;
  68     }
  69 }
  70
  71 bool _backlight_fade_step(int direction)
  72 {
  73     bool done;
  74     switch(direction)
  75     {
  76         case FADING_UP:
  77             done = _backlight_fade_up();
  78         break;
  79         case FADING_DOWN:
  80             done = _backlight_fade_down();
  81         break;
  82         default:
  83             done = true;
  84         break;
  85     }
  86     return(done);
  87 }