/*
Copyright 2012 Jun Wako <wakojun@gmail.com>

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 program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/*
 * scan matrix
 */
#include <stdint.h>
#include <stdbool.h>
#include <avr/io.h>
#include <util/delay.h>
#include "print.h"
#include "debug.h"
#include "util.h"
#include "matrix.h"


#ifndef DEBOUNCE
#   define DEBOUNCE	5
#endif
static uint8_t debouncing = DEBOUNCE;

/* matrix state(1:on, 0:off) */
static matrix_row_t matrix[MATRIX_ROWS];
static matrix_row_t matrix_debouncing[MATRIX_ROWS];

static matrix_row_t read_cols(void);
static void init_cols(void);
static void unselect_rows(void);
static void select_row(uint8_t row);


inline
uint8_t matrix_rows(void)
{
    return MATRIX_ROWS;
}

inline
uint8_t matrix_cols(void)
{
    return MATRIX_COLS;
}

void matrix_init(void)
{
    // enable usb for FaceU
    DDRD  |=  (1<<PD5);
    PORTD &= ~(1<<PD5);

    // initialize row and col
    unselect_rows();
    init_cols();

    // initialize matrix state: all keys off
    for (uint8_t i=0; i < MATRIX_ROWS; i++) {
        matrix[i] = 0;
        matrix_debouncing[i] = 0;
    }
}

uint8_t matrix_scan(void)
{
    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
        select_row(i);
        _delay_us(30);  // without this wait read unstable value.
        matrix_row_t cols = read_cols();
        if (matrix_debouncing[i] != cols) {
            matrix_debouncing[i] = cols;
            if (debouncing) {
                debug("bounce!: "); debug_hex(debouncing); debug("\n");
            }
            debouncing = DEBOUNCE;
        }
        unselect_rows();
    }

    if (debouncing) {
        if (--debouncing) {
            _delay_ms(1);
        } else {
            for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
                matrix[i] = matrix_debouncing[i];
            }
        }
    }

    return 1;
}

bool matrix_is_modified(void)
{
    if (debouncing) return false;
    return true;
}

inline
bool matrix_is_on(uint8_t row, uint8_t col)
{
    return (matrix[row] & ((matrix_row_t)1<<col));
}

inline
matrix_row_t matrix_get_row(uint8_t row)
{
    return matrix[row];
}

void matrix_print(void)
{
    print("\nr/c 0123456789ABCDEF\n");
    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
        phex(row); print(": ");
        pbin_reverse16(matrix_get_row(row));
        print("\n");
    }
}

uint8_t matrix_key_count(void)
{
    uint8_t count = 0;
    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
        count += bitpop16(matrix[i]);
    }
    return count;
}

/* Column pin configuration
 * pin: B0  B1  B2  B3  B4  B5  B6  B7  
 */
static void  init_cols(void)
{
    // Input with pull-up(DDR:0, PORT:1)
    DDRB  &= ~(1<<PB7 | 1<<PB6 | 1<<PB5 | 1<<PB4 | 1<<PB3 | 1<<PB2 | 1<<PB1 | 1<<PB0);
    PORTB |=  (1<<PB7 | 1<<PB6 | 1<<PB5 | 1<<PB4 | 1<<PB3 | 1<<PB2 | 1<<PB1 | 1<<PB0);
}

/* Column pin configuration
 * col: 0   1   2   3   4   5   6   7
 * pin: B0  B1  B2  B3  B4  B5  B6  B7  
 */
static matrix_row_t read_cols(void)
{
    return PINB & (1<<PB7 | 1<<PB6 | 1<<PB5 | 1<<PB4 | 1<<PB3 | 1<<PB2 | 1<<PB1 | 1<<PB0);
}

/* Row pin configuration
 * pin: A0  A1  A2  A3  A4  A5  A6  A7  C7  C6  C5  C4  C3  C2  C1  C0
 */
static void unselect_rows(void)
{
    // Hi-Z(DDR:0, PORT:0) to unselect
    DDRA  &= ~(1<<PA7 | 1<<PA6 | 1<<PA5 | 1<<PA4 | 1<<PA3 | 1<<PA2 | 1<<PA1 | 1<<PA0);
    PORTA &= ~(1<<PA7 | 1<<PA6 | 1<<PA5 | 1<<PA4 | 1<<PA3 | 1<<PA2 | 1<<PA1 | 1<<PA0);
    DDRD  &= ~(1<<PD7 | 1<<PD6 | 1<<PD5 | 1<<PD4 | 1<<PD3 | 1<<PD2 | 1<<PD1 | 1<<PD0);
    PORTD &= ~(1<<PD7 | 1<<PD6 | 1<<PD5 | 1<<PD4 | 1<<PD3 | 1<<PD2 | 1<<PD1 | 1<<PD0);
}

/* Row pin configuration
 * row: 0   1   2   3   4   5   6   7   8   9   10  11  12  13  14  15
 * pin: A0  A1  A2  A3  A4  A5  A6  A7  C7  C6  C5  C4  C3  C2  C1  C0
 */
static void select_row(uint8_t row)
{
    // Output low(DDR:1, PORT:0) to select
    if (row < 8) {
        DDRA  |=  (1 << row);
        PORTA &= ~(1 << row);
    }
    else {
        DDRD  |=  (1 << (15 - row));
        PORTD &= ~(1 << (15 - row));
    }
}