firmware/drivers/rtc/rtc_mr100.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2008 by Robert Kukla 
 * 
 * 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 "rtc.h" 
#include "logf.h"
#include "sw_i2c.h"
#include "i2c-pp.h"

/* The RTC chip is unknown, the information about it was gathered by 
 * reverse engineering the bootloader.
 */

#define RTC_ADDR   0x60

#define RTC_CMD_CTRL 0 /* OF uses it with single byte 1 or 2 */
#define RTC_CMD_UNKN 1 /* OF uses it with single byte 8 */
#define RTC_CMD_DATA 2
#define RTC_CMD_TEST 7 /* OF uses it with single byte 0xAA */

/* private */

static void reverse_bits(unsigned char* v, int size) {

    int i,j,in,out=0;

    for(j=0; j<size; j++) {   
        in = v[j];
        out = in;
        for(i=0; i<7; i++) {
           in  = in >>1;
           out = out<<1;
           out |= (in & 1);
        }   
        v[j] = out;
    }   
}    

static int sw_i2c(int access, int cmd, unsigned char* buf, int count) {
    int i, addr;

    i2c_lock();
    GPIOC_ENABLE |=  0x00000030;

    addr = RTC_ADDR | (cmd<<1);

    if(access == SW_I2C_READ) {
        i = sw_i2c_read(addr, 0, buf, count);
        reverse_bits(buf, count);
    } else {
        reverse_bits(buf, count);
        i = sw_i2c_write(addr, 0, buf, count);
    }    

    GPIOC_ENABLE &= ~0x00000030;
    i2c_unlock();
    
    return i;
}

/* public */

void rtc_init(void)
{
    sw_i2c_init();
 
#if 0    
    /* init sequence from OF for reference */
    /* currently we rely on the bootloader doing it for us */       
    
    bool flag = true;
    unsigned char data;   
    unsigned char v[7] = {0x00,0x47,0x17,0x06,0x03,0x02,0x08}; /* random time */
    
    if(flag) { 
        
        GPIOB_ENABLE |= 0x80;
        GPIOB_OUTPUT_EN |= 0x80;
        GPIOB_OUTPUT_VAL &= ~0x80;
        
        DEV_EN |= 0x1000;
        /* some more stuff that is not clear */ 
        
        sw_i2c(SW_I2C_READ, RTC_CMD_CTRL, &data, 1);       
        if((data<<0x18)>>0x1e) {        /* bit 7 & 6 */
            
            data = 1;
            sw_i2c(SW_I2C_WRITE, RTC_CMD_CTRL, &data, 1);
    
            data = 1;
            sw_i2c(SW_I2C_WRITE, RTC_CMD_CTRL, &data, 1);
        
            data = 8;
            sw_i2c(SW_I2C_WRITE, RTC_CMD_UNKN, &data, 1);
        
            /* more stuff, perhaps set up time array? */
            
            rtc_write_datetime(v);
                
        }
        data = 2;
        sw_i2c(SW_I2C_WRITE, RTC_CMD_CTRL, &data, 1);
    
    }
    data = 2;
    sw_i2c(SW_I2C_WRITE, RTC_CMD_CTRL, &data, 1);   
#endif    

}

int rtc_read_datetime(unsigned char* buf)
{
    int i;
    unsigned char v[7];

    i = sw_i2c(SW_I2C_READ, RTC_CMD_DATA, v, 7);

    v[4] &= 0x3f; /* mask out p.m. flag */
    
    for(i=0; i<7; i++) 
        buf[i] = v[6-i];
    
    return i;
}

int rtc_write_datetime(unsigned char* buf)
{
    int i;
    unsigned char v[7];

    for(i=0; i<7; i++) 
        v[i]=buf[6-i];
        
    i = sw_i2c(SW_I2C_WRITE, RTC_CMD_DATA, v, 7);
    
    return i;
}