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239 lines
6.4 KiB
C
239 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* (C) Copyright 2007
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* Larry Johnson, lrj@acm.org
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*
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* based on rtc/m41t11.c which is ...
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*
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* (C) Copyright 2002
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* Andrew May, Viasat Inc, amay@viasat.com
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*/
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/*
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* STMicroelectronics M41T60 serial access real-time clock
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*/
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/* #define DEBUG 1 */
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#include <common.h>
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#include <command.h>
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#include <env.h>
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#include <log.h>
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#include <rtc.h>
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#include <i2c.h>
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/*
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* Convert between century and "century bits" (CB1 and CB0). These routines
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* assume years are in the range 1900 - 2299.
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*/
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static unsigned char year2cb(unsigned const year)
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{
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if (year < 1900 || year >= 2300)
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printf("M41T60 RTC: year %d out of range\n", year);
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return (year / 100) & 0x3;
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}
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static unsigned cb2year(unsigned const cb)
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{
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return 1900 + 100 * ((cb + 1) & 0x3);
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}
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/*
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* These are simple defines for the chip local to here so they aren't too
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* verbose. DAY/DATE aren't nice but that is how they are on the data sheet.
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*/
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#define RTC_SEC 0x0
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#define RTC_MIN 0x1
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#define RTC_HOUR 0x2
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#define RTC_DAY 0x3
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#define RTC_DATE 0x4
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#define RTC_MONTH 0x5
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#define RTC_YEAR 0x6
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#define RTC_REG_CNT 7
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#define RTC_CTRL 0x7
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#if defined(DEBUG)
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static void rtc_dump(char const *const label)
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{
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uchar data[8];
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if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
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printf("I2C read failed in rtc_dump()\n");
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return;
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}
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printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n",
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label, data[0], data[1], data[2], data[3],
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data[4], data[5], data[6], data[7]);
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}
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#else
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#define rtc_dump(label)
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#endif
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static uchar *rtc_validate(void)
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{
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/*
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* This routine uses the OUT bit and the validity of the time values to
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* determine whether there has been an initial power-up since the last
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* time the routine was run. It assumes that the OUT bit is not being
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* used for any other purpose.
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*/
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static const uchar daysInMonth[0x13] = {
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0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31,
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0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x31, 0x30, 0x31
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};
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static uchar data[8];
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uchar min, date, month, years;
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rtc_dump("begin validate");
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if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
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printf("I2C read failed in rtc_validate()\n");
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return 0;
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}
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/*
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* If the OUT bit is "1", there has been a loss of power, so stop the
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* oscillator so it can be "kick-started" as per data sheet.
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*/
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if (0x00 != (data[RTC_CTRL] & 0x80)) {
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printf("M41T60 RTC clock lost power.\n");
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data[RTC_SEC] = 0x80;
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if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC, 1, data, 1)) {
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printf("I2C write failed in rtc_validate()\n");
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return 0;
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}
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}
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/*
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* If the oscillator is stopped or the date is invalid, then reset the
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* OUT bit to "0", reset the date registers, and start the oscillator.
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*/
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min = data[RTC_MIN] & 0x7F;
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date = data[RTC_DATE];
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month = data[RTC_MONTH] & 0x3F;
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years = data[RTC_YEAR];
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if (0x59 < data[RTC_SEC] || 0x09 < (data[RTC_SEC] & 0x0F) ||
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0x59 < min || 0x09 < (min & 0x0F) ||
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0x23 < data[RTC_HOUR] || 0x09 < (data[RTC_HOUR] & 0x0F) ||
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0x07 < data[RTC_DAY] || 0x00 == data[RTC_DAY] ||
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0x12 < month ||
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0x99 < years || 0x09 < (years & 0x0F) ||
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daysInMonth[month] < date || 0x09 < (date & 0x0F) || 0x00 == date ||
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(0x29 == date && 0x02 == month &&
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((0x00 != (years & 0x03)) ||
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(0x00 == years && 0x00 != (data[RTC_MONTH] & 0xC0))))) {
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printf("Resetting M41T60 RTC clock.\n");
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/*
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* Set to 00:00:00 1900-01-01 (Monday)
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*/
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data[RTC_SEC] = 0x00;
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data[RTC_MIN] &= 0x80; /* preserve OFIE bit */
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data[RTC_HOUR] = 0x00;
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data[RTC_DAY] = 0x02;
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data[RTC_DATE] = 0x01;
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data[RTC_MONTH] = 0xC1;
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data[RTC_YEAR] = 0x00;
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data[RTC_CTRL] &= 0x7F; /* reset OUT bit */
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if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) {
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printf("I2C write failed in rtc_validate()\n");
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return 0;
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}
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}
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return data;
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}
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int rtc_get(struct rtc_time *tmp)
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{
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uchar const *const data = rtc_validate();
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if (!data)
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return -1;
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tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F);
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tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F);
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tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F);
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tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F);
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tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F);
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tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]);
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tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1;
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tmp->tm_yday = 0;
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tmp->tm_isdst = 0;
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debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
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tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
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tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
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return 0;
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}
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int rtc_set(struct rtc_time *tmp)
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{
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uchar *const data = rtc_validate();
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if (!data)
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return -1;
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debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
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tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
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tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
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data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F);
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data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F);
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data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F;
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data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F;
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data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F;
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data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100);
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data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6;
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data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07;
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if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, RTC_REG_CNT)) {
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printf("I2C write failed in rtc_set()\n");
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return -1;
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}
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return 0;
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}
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void rtc_reset(void)
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{
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uchar *const data = rtc_validate();
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char const *const s = env_get("rtccal");
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if (!data)
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return;
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rtc_dump("begin reset");
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/*
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* If environmental variable "rtccal" is present, it must be a hex value
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* between 0x00 and 0x3F, inclusive. The five least-significan bits
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* represent the calibration magnitude, and the sixth bit the sign bit.
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* If these do not match the contents of the hardware register, that
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* register is updated. The value 0x00 imples no correction. Consult
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* the M41T60 documentation for further details.
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*/
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if (s) {
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unsigned long const l = simple_strtoul(s, 0, 16);
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if (l <= 0x3F) {
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if ((data[RTC_CTRL] & 0x3F) != l) {
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printf("Setting RTC calibration to 0x%02lX\n",
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l);
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data[RTC_CTRL] &= 0xC0;
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data[RTC_CTRL] |= (uchar) l;
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}
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} else
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printf("environment parameter \"rtccal\" not valid: "
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"ignoring\n");
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}
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/*
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* Turn off frequency test.
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*/
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data[RTC_CTRL] &= 0xBF;
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if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CTRL, 1, data + RTC_CTRL, 1)) {
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printf("I2C write failed in rtc_reset()\n");
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return;
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}
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rtc_dump("end reset");
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}
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