/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id: button-clip.c 19311 2008-12-03 11:30:18Z funman $
 *
 * Copyright (C) 2009 Bertrik Sikken
 * Copyright (C) 2008 François Dinel
 * Copyright (C) 2008 Rafaël Carré
 *
 * 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 "button-target.h"
#include "as3525.h"
#include "kernel.h"

/*  The Sansa Clip uses a button matrix that is scanned by selecting one of
    three rows and reading back the button states from the columns.
    
    In this driver, a kernel tick task is used to alternate between rows.
    In one tick, column data from one row is read back and then the next row
    is selected for the following tick. This mechanism ensures that there is
    plenty time between selecting a row and reading the colums, avoiding the
    need for explicit delays.
*/

static int buttons = 0;

static void button_tick(void)
{
    static int row = 0;
    int temp;

    if(button_hold()) {
        buttons = 0;
        return;
    }
    
    temp = buttons;
        
    /* direct GPIO connections */
    if (GPIOA_PIN(7))
        temp |= BUTTON_POWER;
    else
        temp &= ~BUTTON_POWER;

    /* This is a keypad using C4-C6 as columns and B0-B2 as rows */
    switch (row) {
    
    case 0:
        temp &= ~(BUTTON_VOL_UP | BUTTON_UP);
    
        (void)GPIOB_PIN(0); /* C4B0 is unused */

        if (GPIOB_PIN(1))
            temp |= BUTTON_VOL_UP;

        if (GPIOB_PIN(2))
            temp |= BUTTON_UP;

        GPIOC_PIN(4) = 0;
        GPIOC_PIN(5) = (1<<5);
        row++;
        break;
        
    case 1:
        temp &= ~(BUTTON_LEFT | BUTTON_SELECT | BUTTON_RIGHT);

        if (GPIOB_PIN(0))
            temp |= BUTTON_LEFT;

        if (GPIOB_PIN(1))
            temp |= BUTTON_SELECT;

        if (GPIOB_PIN(2))
            temp |= BUTTON_RIGHT;

        GPIOC_PIN(5) = 0;
        GPIOC_PIN(6) = (1<<6);
        row++;
        break;

    case 2:        
        temp &= ~(BUTTON_DOWN | BUTTON_VOL_DOWN | BUTTON_HOME);

        if (GPIOB_PIN(0))
            temp |= BUTTON_DOWN;

        if (GPIOB_PIN(1))
            temp |= BUTTON_VOL_DOWN;

        if (GPIOB_PIN(2))
            temp |= BUTTON_HOME;

        GPIOC_PIN(6) = 0;
        GPIOC_PIN(4) = (1<<4);
        
    default:
        row = 0;
        break;
    }
    
    buttons = temp;
}

int button_read_device(void)
{
    return buttons;
}

bool button_hold(void)
{
    return (GPIOA_PIN(3) != 0);
}

void button_init_device(void)
{
    GPIOA_DIR &= ~((1<<7) | (1<<3));
    GPIOB_DIR &= ~((1<<2) | (1<<1) | (1<<0));
    GPIOC_PIN(4) = 0;
    GPIOC_PIN(5) = 0;
    GPIOC_PIN(6) = 0;
    GPIOC_DIR |= ((1<<6) | (1<<5) | (1<<4));
    
    tick_add_task(button_tick);
}