/* * (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(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; } int rtc_set(struct rtc_time *tmp) { uchar *const data = rtc_validate(); if (!data) return -1; 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 -1; } return 0; } 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%02lX\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 */