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/*
* Copyright 2001 MontaVista Software Inc.
* Author: jsun@mvista.com or jsun@junsun.net
*
* arch/mips/ddb5xxx/common/rtc_ds1386.c
* low-level RTC hookups for s for Dallas 1396 chip.
*
* 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 file exports a function, rtc_ds1386_init(), which expects an
* uncached base address as the argument. It will set the two function
* pointers expected by the MIPS generic timer code.
*/
#include <linux/types.h>
#include <linux/time.h>
#include <linux/bcd.h>
#include <asm/time.h>
#include <asm/addrspace.h>
#include <asm/mc146818rtc.h>
#include <asm/debug.h>
#define EPOCH 2000
#define READ_RTC(x) *(volatile unsigned char*)(rtc_base+x)
#define WRITE_RTC(x, y) *(volatile unsigned char*)(rtc_base+x) = y
static unsigned long rtc_base;
static unsigned long
rtc_ds1386_get_time(void)
{
u8 byte;
u8 temp;
unsigned int year, month, day, hour, minute, second;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
/* let us freeze external registers */
byte = READ_RTC(0xB);
byte &= 0x3f;
WRITE_RTC(0xB, byte);
/* read time data */
year = BCD2BIN(READ_RTC(0xA)) + EPOCH;
month = BCD2BIN(READ_RTC(0x9) & 0x1f);
day = BCD2BIN(READ_RTC(0x8));
minute = BCD2BIN(READ_RTC(0x2));
second = BCD2BIN(READ_RTC(0x1));
/* hour is special - deal with it later */
temp = READ_RTC(0x4);
/* enable time transfer */
byte |= 0x80;
WRITE_RTC(0xB, byte);
spin_unlock_irqrestore(&rtc_lock, flags);
/* calc hour */
if (temp & 0x40) {
/* 12 hour format */
hour = BCD2BIN(temp & 0x1f);
if (temp & 0x20) hour += 12; /* PM */
} else {
/* 24 hour format */
hour = BCD2BIN(temp & 0x3f);
}
return mktime(year, month, day, hour, minute, second);
}
static int
rtc_ds1386_set_time(unsigned long t)
{
struct rtc_time tm;
u8 byte;
u8 temp;
u8 year, month, day, hour, minute, second;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
/* let us freeze external registers */
byte = READ_RTC(0xB);
byte &= 0x3f;
WRITE_RTC(0xB, byte);
/* convert */
to_tm(t, &tm);
/* check each field one by one */
year = BIN2BCD(tm.tm_year - EPOCH);
if (year != READ_RTC(0xA)) {
WRITE_RTC(0xA, year);
}
temp = READ_RTC(0x9);
month = BIN2BCD(tm.tm_mon+1); /* tm_mon starts from 0 to 11 */
if (month != (temp & 0x1f)) {
WRITE_RTC( 0x9,
(month & 0x1f) | (temp & ~0x1f) );
}
day = BIN2BCD(tm.tm_mday);
if (day != READ_RTC(0x8)) {
WRITE_RTC(0x8, day);
}
temp = READ_RTC(0x4);
if (temp & 0x40) {
/* 12 hour format */
hour = 0x40;
if (tm.tm_hour > 12) {
hour |= 0x20 | (BIN2BCD(hour-12) & 0x1f);
} else {
hour |= BIN2BCD(tm.tm_hour);
}
} else {
/* 24 hour format */
hour = BIN2BCD(tm.tm_hour) & 0x3f;
}
if (hour != temp) WRITE_RTC(0x4, hour);
minute = BIN2BCD(tm.tm_min);
if (minute != READ_RTC(0x2)) {
WRITE_RTC(0x2, minute);
}
second = BIN2BCD(tm.tm_sec);
if (second != READ_RTC(0x1)) {
WRITE_RTC(0x1, second);
}
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
void
rtc_ds1386_init(unsigned long base)
{
unsigned char byte;
/* remember the base */
rtc_base = base;
db_assert((rtc_base & 0xe0000000) == KSEG1);
/* turn on RTC if it is not on */
byte = READ_RTC(0x9);
if (byte & 0x80) {
byte &= 0x7f;
WRITE_RTC(0x9, byte);
}
/* enable time transfer */
byte = READ_RTC(0xB);
byte |= 0x80;
WRITE_RTC(0xB, byte);
/* set the function pointers */
rtc_get_time = rtc_ds1386_get_time;
rtc_set_time = rtc_ds1386_set_time;
}
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