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/*
* (C) Copyright 2007
* Larry Johnson, lrj@acm.org
*
* based on rtc/m41t11.c which is ...
*
* (C) Copyright 2002
* Andrew May, Viasat Inc, amay@viasat.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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* STMicroelectronics M41T60 serial access real-time clock
*/
/* #define DEBUG 1 */
#include <common.h>
#include <command.h>
#include <rtc.h>
#include <i2c.h>
#if defined(CONFIG_RTC_M41T60) && defined(CFG_I2C_RTC_ADDR) && \
defined(CONFIG_CMD_DATE)
static unsigned bcd2bin(uchar n)
{
return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
}
static unsigned char bin2bcd(unsigned int n)
{
return (((n / 10) << 4) | (n % 10));
}
/*
* Convert between century and "century bits" (CB1 and CB0). These routines
* assume years are in the range 1900 - 2299.
*/
static unsigned char year2cb(unsigned const year)
{
if (year < 1900 || year >= 2300)
printf("M41T60 RTC: year %d out of range\n", year);
return (year / 100) & 0x3;
}
static unsigned cb2year(unsigned const cb)
{
return 1900 + 100 * ((cb + 1) & 0x3);
}
/*
* These are simple defines for the chip local to here so they aren't too
* verbose. DAY/DATE aren't nice but that is how they are on the data sheet.
*/
#define RTC_SEC 0x0
#define RTC_MIN 0x1
#define RTC_HOUR 0x2
#define RTC_DAY 0x3
#define RTC_DATE 0x4
#define RTC_MONTH 0x5
#define RTC_YEAR 0x6
#define RTC_REG_CNT 7
#define RTC_CTRL 0x7
#if defined(DEBUG)
static void rtc_dump(char const *const label)
{
uchar data[8];
if (i2c_read(CFG_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
printf("I2C read failed in rtc_dump()\n");
return;
}
printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n",
label, data[0], data[1], data[2], data[3],
data[4], data[5], data[6], data[7]);
}
#else
#define rtc_dump(label)
#endif
static uchar *rtc_validate(void)
{
/*
* This routine uses the OUT bit and the validity of the time values to
* determine whether there has been an initial power-up since the last
* time the routine was run. It assumes that the OUT bit is not being
* used for any other purpose.
*/
static const uchar daysInMonth[0x13] = {
0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31,
0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x31, 0x30, 0x31
};
static uchar data[8];
uchar min, date, month, years;
rtc_dump("begin validate");
if (i2c_read(CFG_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
printf("I2C read failed in rtc_validate()\n");
return 0;
}
/*
* If the OUT bit is "1", there has been a loss of power, so stop the
* oscillator so it can be "kick-started" as per data sheet.
*/
if (0x00 != (data[RTC_CTRL] & 0x80)) {
printf("M41T60 RTC clock lost power.\n");
data[RTC_SEC] = 0x80;
if (i2c_write(CFG_I2C_RTC_ADDR, RTC_SEC, 1, data, 1)) {
printf("I2C write failed in rtc_validate()\n");
return 0;
}
}
/*
* If the oscillator is stopped or the date is invalid, then reset the
* OUT bit to "0", reset the date registers, and start the oscillator.
*/
min = data[RTC_MIN] & 0x7F;
date = data[RTC_DATE];
month = data[RTC_MONTH] & 0x3F;
years = data[RTC_YEAR];
if (0x59 < data[RTC_SEC] || 0x09 < (data[RTC_SEC] & 0x0F) ||
0x59 < min || 0x09 < (min & 0x0F) ||
0x23 < data[RTC_HOUR] || 0x09 < (data[RTC_HOUR] & 0x0F) ||
0x07 < data[RTC_DAY] || 0x00 == data[RTC_DAY] ||
0x12 < month ||
0x99 < years || 0x09 < (years & 0x0F) ||
daysInMonth[month] < date || 0x09 < (date & 0x0F) || 0x00 == date ||
(0x29 == date && 0x02 == month &&
((0x00 != (years & 0x03)) ||
(0x00 == years && 0x00 != (data[RTC_MONTH] & 0xC0))))) {
printf("Resetting M41T60 RTC clock.\n");
/*
* Set to 00:00:00 1900-01-01 (Monday)
*/
data[RTC_SEC] = 0x00;
data[RTC_MIN] &= 0x80; /* preserve OFIE bit */
data[RTC_HOUR] = 0x00;
data[RTC_DAY] = 0x02;
data[RTC_DATE] = 0x01;
data[RTC_MONTH] = 0xC1;
data[RTC_YEAR] = 0x00;
data[RTC_CTRL] &= 0x7F; /* reset OUT bit */
if (i2c_write(CFG_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
printf("I2C write failed in rtc_validate()\n");
return 0;
}
}
return data;
}
int rtc_get(struct rtc_time *tmp)
{
uchar const *const data = rtc_validate();
if (!data)
return -1;
tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F);
tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F);
tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F);
tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F);
tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F);
tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]);
tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1;
tmp->tm_yday = 0;
tmp->tm_isdst = 0;
debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
return 0;
}
void rtc_set(struct rtc_time *tmp)
{
uchar *const data = rtc_validate();
if (!data)
return;
debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F);
data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F);
data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F;
data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F;
data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F;
data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100);
data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6;
data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07;
if (i2c_write(CFG_I2C_RTC_ADDR, 0, 1, data, RTC_REG_CNT)) {
printf("I2C write failed in rtc_set()\n");
return;
}
}
void rtc_reset(void)
{
uchar *const data = rtc_validate();
char const *const s = getenv("rtccal");
if (!data)
return;
rtc_dump("begin reset");
/*
* If environmental variable "rtccal" is present, it must be a hex value
* between 0x00 and 0x3F, inclusive. The five least-significan bits
* represent the calibration magnitude, and the sixth bit the sign bit.
* If these do not match the contents of the hardware register, that
* register is updated. The value 0x00 imples no correction. Consult
* the M41T60 documentation for further details.
*/
if (s) {
unsigned long const l = simple_strtoul(s, 0, 16);
if (l <= 0x3F) {
if ((data[RTC_CTRL] & 0x3F) != l) {
printf("Setting RTC calibration to 0x%02X\n",
l);
data[RTC_CTRL] &= 0xC0;
data[RTC_CTRL] |= (uchar) l;
}
} else
printf("environment parameter \"rtccal\" not valid: "
"ignoring\n");
}
/*
* Turn off frequency test.
*/
data[RTC_CTRL] &= 0xBF;
if (i2c_write(CFG_I2C_RTC_ADDR, RTC_CTRL, 1, data + RTC_CTRL, 1)) {
printf("I2C write failed in rtc_reset()\n");
return;
}
rtc_dump("end reset");
}
#endif /* CONFIG_RTC_M41T60 && CFG_I2C_RTC_ADDR && CONFIG_CMD_DATE */
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