rtc_xicor1241.c

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/*
 * Copyright (C) 2000, 2001 Broadcom Corporation
 *
 * Copyright (C) 2002 MontaVista Software Inc.
 * Author: [email protected] or [email protected]
 *
 * 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.
 */
#include <linux/bcd.h>
#include <linux/types.h>
#include <linux/time.h>

#include <asm/time.h>
#include <asm/addrspace.h>
#include <asm/io.h>

#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_smbus.h>


/* Xicor 1241 definitions */

/*
 * Register bits
 */

#define X1241REG_SR_BAT 0x80        /* currently on battery power */
#define X1241REG_SR_RWEL 0x04       /* r/w latch is enabled, can write RTC */
#define X1241REG_SR_WEL 0x02        /* r/w latch is unlocked, can enable r/w now */
#define X1241REG_SR_RTCF 0x01       /* clock failed */
#define X1241REG_BL_BP2 0x80        /* block protect 2 */
#define X1241REG_BL_BP1 0x40        /* block protect 1 */
#define X1241REG_BL_BP0 0x20        /* block protect 0 */
#define X1241REG_BL_WD1 0x10
#define X1241REG_BL_WD0 0x08
#define X1241REG_HR_MIL 0x80        /* military time format */

/*
 * Register numbers
 */

#define X1241REG_BL 0x10        /* block protect bits */
#define X1241REG_INT    0x11        /*  */
#define X1241REG_SC 0x30        /* Seconds */
#define X1241REG_MN 0x31        /* Minutes */
#define X1241REG_HR 0x32        /* Hours */
#define X1241REG_DT 0x33        /* Day of month */
#define X1241REG_MO 0x34        /* Month */
#define X1241REG_YR 0x35        /* Year */
#define X1241REG_DW 0x36        /* Day of Week */
#define X1241REG_Y2K    0x37        /* Year 2K */
#define X1241REG_SR 0x3F        /* Status register */

#define X1241_CCR_ADDRESS   0x6F

#define SMB_CSR(reg)    IOADDR(A_SMB_REGISTER(1, reg))

static int xicor_read(uint8_t addr)
{
        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

    __raw_writeq((addr >> 8) & 0x7, SMB_CSR(R_SMB_CMD));
    __raw_writeq(addr & 0xff, SMB_CSR(R_SMB_DATA));
    __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR2BYTE,
             SMB_CSR(R_SMB_START));

        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

    __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_RD1BYTE,
             SMB_CSR(R_SMB_START));

        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

        if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
                /* Clear error bit by writing a 1 */
                __raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
                return -1;
        }

    return (__raw_readq(SMB_CSR(R_SMB_DATA)) & 0xff);
}

static int xicor_write(uint8_t addr, int b)
{
        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

    __raw_writeq(addr, SMB_CSR(R_SMB_CMD));
    __raw_writeq((addr & 0xff) | ((b & 0xff) << 8), SMB_CSR(R_SMB_DATA));
    __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR3BYTE,
             SMB_CSR(R_SMB_START));

        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

        if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
                /* Clear error bit by writing a 1 */
                __raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
                return -1;
        } else {
        return 0;
    }
}

int xicor_set_time(unsigned long t)
{
    struct rtc_time tm;
    int tmp;
    unsigned long flags;

    rtc_time_to_tm(t, &tm);
    tm.tm_year += 1900;

    spin_lock_irqsave(&rtc_lock, flags);
    /* unlock writes to the CCR */
    xicor_write(X1241REG_SR, X1241REG_SR_WEL);
    xicor_write(X1241REG_SR, X1241REG_SR_WEL | X1241REG_SR_RWEL);

    /* trivial ones */
    tm.tm_sec = bin2bcd(tm.tm_sec);
    xicor_write(X1241REG_SC, tm.tm_sec);

    tm.tm_min = bin2bcd(tm.tm_min);
    xicor_write(X1241REG_MN, tm.tm_min);

    tm.tm_mday = bin2bcd(tm.tm_mday);
    xicor_write(X1241REG_DT, tm.tm_mday);

    /* tm_mon starts from 0, *ick* */
    tm.tm_mon ++;
    tm.tm_mon = bin2bcd(tm.tm_mon);
    xicor_write(X1241REG_MO, tm.tm_mon);

    /* year is split */
    tmp = tm.tm_year / 100;
    tm.tm_year %= 100;
    xicor_write(X1241REG_YR, tm.tm_year);
    xicor_write(X1241REG_Y2K, tmp);

    /* hour is the most tricky one */
    tmp = xicor_read(X1241REG_HR);
    if (tmp & X1241REG_HR_MIL) {
        /* 24 hour format */
        tm.tm_hour = bin2bcd(tm.tm_hour);
        tmp = (tmp & ~0x3f) | (tm.tm_hour & 0x3f);
    } else {
        /* 12 hour format, with 0x2 for pm */
        tmp = tmp & ~0x3f;
        if (tm.tm_hour >= 12) {
            tmp |= 0x20;
            tm.tm_hour -= 12;
        }
        tm.tm_hour = bin2bcd(tm.tm_hour);
        tmp |= tm.tm_hour;
    }
    xicor_write(X1241REG_HR, tmp);

    xicor_write(X1241REG_SR, 0);
    spin_unlock_irqrestore(&rtc_lock, flags);

    return 0;
}

unsigned long xicor_get_time(void)
{
    unsigned int year, mon, day, hour, min, sec, y2k;
    unsigned long flags;

    spin_lock_irqsave(&rtc_lock, flags);
    sec = xicor_read(X1241REG_SC);
    min = xicor_read(X1241REG_MN);
    hour = xicor_read(X1241REG_HR);

    if (hour & X1241REG_HR_MIL) {
        hour &= 0x3f;
    } else {
        if (hour & 0x20)
            hour = (hour & 0xf) + 0x12;
    }

    day = xicor_read(X1241REG_DT);
    mon = xicor_read(X1241REG_MO);
    year = xicor_read(X1241REG_YR);
    y2k = xicor_read(X1241REG_Y2K);
    spin_unlock_irqrestore(&rtc_lock, flags);

    sec = bcd2bin(sec);
    min = bcd2bin(min);
    hour = bcd2bin(hour);
    day = bcd2bin(day);
    mon = bcd2bin(mon);
    year = bcd2bin(year);
    y2k = bcd2bin(y2k);

    year += (y2k * 100);

    return mktime(year, mon, day, hour, min, sec);
}

int xicor_probe(void)
{
    return (xicor_read(X1241REG_SC) != -1);
}