/*
 * rs5c372.c
 *
 * Device driver for Ricoh's Real Time Controller RS5C372A.
 *
 * Copyright (C) 2004 Gary Jennejohn garyj@denx.de
 *
 * Based in part in ds1307.c -
 * (C) Copyright 2001, 2002, 2003
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 * Keith Outwater, keith_outwater@mvis.com`
 * Steven Scholz, steven.scholz@imc-berlin.de
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <common.h>
#include <command.h>
#include <rtc.h>
#include <i2c.h>

/*
 * Reads are always done starting with register 15, which requires some
 * jumping-through-hoops to access the data correctly.
 *
 * Writes are always done starting with register 0.
 */

#define DEBUG 0

#if DEBUG
static unsigned int rtc_debug = DEBUG;
#else
#define rtc_debug 0     /* gcc will remove all the debug code for us */
#endif

#ifndef CONFIG_SYS_I2C_RTC_ADDR
#define CONFIG_SYS_I2C_RTC_ADDR 0x32
#endif

#define RS5C372_RAM_SIZE 0x10
#define RATE_32000HZ    0x80    /* Rate Select 32.000KHz */
#define RATE_32768HZ    0x00    /* Rate Select 32.768KHz */

#define STATUS_XPT  0x10    /* data invalid because voltage was 0 */

#define USE_24HOUR_MODE 0x20
#define TWELVE_HOUR_MODE(n) ((((n) >> 5) & 1) == 0)
#define HOURS_AP(n)     (((n) >> 5) & 1)
#define HOURS_12(n)     bcd2bin((n) & 0x1F)
#define HOURS_24(n)     bcd2bin((n) & 0x3F)


static int setup_done = 0;

static int
rs5c372_readram(unsigned char *buf, int len)
{
        int ret;

        ret = i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 0, buf, len);
        if (ret != 0) {
                printf("%s: failed to read\n", __FUNCTION__);
                return ret;
        }

        if (buf[0] & STATUS_XPT)
                printf("### Warning: RTC lost power\n");

        return ret;
}

static void
rs5c372_enable(void)
{
        unsigned char buf[RS5C372_RAM_SIZE + 1];
        int ret;

        /* note that this returns reg. 15 in buf[1] */
        ret = rs5c372_readram(&buf[1], RS5C372_RAM_SIZE);
        if (ret != 0) {
                printf("%s: failed\n", __FUNCTION__);
                return;
        }

        buf[0] = 0;
        /* we want to start writing at register 0 so we have to copy the */
        /* register contents up one slot */
        for (ret = 2; ret < 9; ret++)
                buf[ret - 1] = buf[ret];
        /* registers 0 to 6 (time values) are not touched */
        buf[8] = RATE_32768HZ; /* reg. 7 */
        buf[9] = 0; /* reg. 8 */
        buf[10] = 0; /* reg. 9 */
        buf[11] = 0; /* reg. 10 */
        buf[12] = 0; /* reg. 11 */
        buf[13] = 0; /* reg. 12 */
        buf[14] = 0; /* reg. 13 */
        buf[15] = 0; /* reg. 14 */
        buf[16] = USE_24HOUR_MODE; /* reg. 15 */
        ret = i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 0, buf, RS5C372_RAM_SIZE+1);
        if (ret != 0) {
                printf("%s: failed\n", __FUNCTION__);
                return;
        }
        setup_done = 1;

        return;
}

static void
rs5c372_convert_to_time(struct rtc_time *dt, unsigned char *buf)
{
        /* buf[0] is register 15 */
        dt->tm_sec = bcd2bin(buf[1]);
        dt->tm_min = bcd2bin(buf[2]);

        if (TWELVE_HOUR_MODE(buf[0])) {
                dt->tm_hour = HOURS_12(buf[3]);
                if (HOURS_AP(buf[3])) /* PM */
                        dt->tm_hour += 12;
        } else /* 24-hour-mode */
                dt->tm_hour = HOURS_24(buf[3]);

        dt->tm_mday = bcd2bin(buf[5]);
        dt->tm_mon = bcd2bin(buf[6]);
        dt->tm_year = bcd2bin(buf[7]);
        if (dt->tm_year >= 70)
                dt->tm_year += 1900;
        else
                dt->tm_year += 2000;
        /* 0 is Sunday */
        dt->tm_wday = bcd2bin(buf[4] & 0x07);
        dt->tm_yday = 0;
        dt->tm_isdst= 0;

        if(rtc_debug > 2) {
                printf("rs5c372_convert_to_time: year = %d\n", dt->tm_year);
                printf("rs5c372_convert_to_time: mon  = %d\n", dt->tm_mon);
                printf("rs5c372_convert_to_time: mday = %d\n", dt->tm_mday);
                printf("rs5c372_convert_to_time: hour = %d\n", dt->tm_hour);
                printf("rs5c372_convert_to_time: min  = %d\n", dt->tm_min);
                printf("rs5c372_convert_to_time: sec  = %d\n", dt->tm_sec);
        }
}

/*
 * Get the current time from the RTC
 */
int
rtc_get (struct rtc_time *tmp)
{
        unsigned char buf[RS5C372_RAM_SIZE];
        int ret;

        if (!setup_done)
                rs5c372_enable();

        if (!setup_done)
                return -1;

        memset(buf, 0, sizeof(buf));

        /* note that this returns reg. 15 in buf[0] */
        ret = rs5c372_readram(buf, RS5C372_RAM_SIZE);
        if (ret != 0) {
                printf("%s: failed\n", __FUNCTION__);
                return -1;
        }

        rs5c372_convert_to_time(tmp, buf);

        return 0;
}

/*
 * Set the RTC
 */
int rtc_set (struct rtc_time *tmp)
{
        unsigned char buf[8], reg15;
        int ret;

        if (!setup_done)
                rs5c372_enable();

        if (!setup_done)
                return -1;

        if(rtc_debug > 2) {
                printf("rtc_set: tm_year = %d\n", tmp->tm_year);
                printf("rtc_set: tm_mon  = %d\n", tmp->tm_mon);
                printf("rtc_set: tm_mday = %d\n", tmp->tm_mday);
                printf("rtc_set: tm_hour = %d\n", tmp->tm_hour);
                printf("rtc_set: tm_min  = %d\n", tmp->tm_min);
                printf("rtc_set: tm_sec  = %d\n", tmp->tm_sec);
        }

        memset(buf, 0, sizeof(buf));

        /* only read register 15 */
        ret = i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 0, buf, 1);

        if (ret == 0) {
                /* need to save register 15 */
                reg15 = buf[0];
                buf[0] = 0;     /* register address on RS5C372 */
                buf[1] = bin2bcd(tmp->tm_sec);
                buf[2] = bin2bcd(tmp->tm_min);
                /* need to handle 12 hour mode */
                if (TWELVE_HOUR_MODE(reg15)) {
                        if (tmp->tm_hour >= 12) { /* PM */
                                /* 12 PM is a special case */
                                if (tmp->tm_hour == 12)
                                        buf[3] = bin2bcd(tmp->tm_hour);
                                else
                                        buf[3] = bin2bcd(tmp->tm_hour - 12);
                                buf[3] |= 0x20;
                        }
                } else {
                        buf[3] = bin2bcd(tmp->tm_hour);
                }

                buf[4] = bin2bcd(tmp->tm_wday);
                buf[5] = bin2bcd(tmp->tm_mday);
                buf[6] = bin2bcd(tmp->tm_mon);
                if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
                        printf("WARNING: year should be between 1970 and 2069!\n");
                buf[7] = bin2bcd(tmp->tm_year % 100);

                ret = i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 0, buf, 8);
                if (ret != 0) {
                        printf("rs5c372_set_datetime(), i2c_master_send() returned %d\n",ret);
                        return -1;
                }
        } else {
                return -1;
        }

        return 0;
}

/*
 * Reset the RTC.
 */
void
rtc_reset (void)
{
        if (!setup_done)
                rs5c372_enable();
}