1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * (C) Copyright 2007 4 * Larry Johnson, lrj@acm.org 5 * 6 * based on rtc/m41t11.c which is ... 7 * 8 * (C) Copyright 2002 9 * Andrew May, Viasat Inc, amay@viasat.com 10 */ 11 12 /* 13 * STMicroelectronics M41T60 serial access real-time clock 14 */ 15 16 /* #define DEBUG 1 */ 17 18 #include <common.h> 19 #include <command.h> 20 #include <rtc.h> 21 #include <i2c.h> 22 23 /* 24 * Convert between century and "century bits" (CB1 and CB0). These routines 25 * assume years are in the range 1900 - 2299. 26 */ 27 28 static unsigned char year2cb(unsigned const year) 29 { 30 if (year < 1900 || year >= 2300) 31 printf("M41T60 RTC: year %d out of range\n", year); 32 33 return (year / 100) & 0x3; 34 } 35 36 static unsigned cb2year(unsigned const cb) 37 { 38 return 1900 + 100 * ((cb + 1) & 0x3); 39 } 40 41 /* 42 * These are simple defines for the chip local to here so they aren't too 43 * verbose. DAY/DATE aren't nice but that is how they are on the data sheet. 44 */ 45 #define RTC_SEC 0x0 46 #define RTC_MIN 0x1 47 #define RTC_HOUR 0x2 48 #define RTC_DAY 0x3 49 #define RTC_DATE 0x4 50 #define RTC_MONTH 0x5 51 #define RTC_YEAR 0x6 52 53 #define RTC_REG_CNT 7 54 55 #define RTC_CTRL 0x7 56 57 #if defined(DEBUG) 58 static void rtc_dump(char const *const label) 59 { 60 uchar data[8]; 61 62 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 63 printf("I2C read failed in rtc_dump()\n"); 64 return; 65 } 66 printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n", 67 label, data[0], data[1], data[2], data[3], 68 data[4], data[5], data[6], data[7]); 69 } 70 #else 71 #define rtc_dump(label) 72 #endif 73 74 static uchar *rtc_validate(void) 75 { 76 /* 77 * This routine uses the OUT bit and the validity of the time values to 78 * determine whether there has been an initial power-up since the last 79 * time the routine was run. It assumes that the OUT bit is not being 80 * used for any other purpose. 81 */ 82 static const uchar daysInMonth[0x13] = { 83 0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31, 84 0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 85 0x31, 0x30, 0x31 86 }; 87 static uchar data[8]; 88 uchar min, date, month, years; 89 90 rtc_dump("begin validate"); 91 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 92 printf("I2C read failed in rtc_validate()\n"); 93 return 0; 94 } 95 /* 96 * If the OUT bit is "1", there has been a loss of power, so stop the 97 * oscillator so it can be "kick-started" as per data sheet. 98 */ 99 if (0x00 != (data[RTC_CTRL] & 0x80)) { 100 printf("M41T60 RTC clock lost power.\n"); 101 data[RTC_SEC] = 0x80; 102 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC, 1, data, 1)) { 103 printf("I2C write failed in rtc_validate()\n"); 104 return 0; 105 } 106 } 107 /* 108 * If the oscillator is stopped or the date is invalid, then reset the 109 * OUT bit to "0", reset the date registers, and start the oscillator. 110 */ 111 min = data[RTC_MIN] & 0x7F; 112 date = data[RTC_DATE]; 113 month = data[RTC_MONTH] & 0x3F; 114 years = data[RTC_YEAR]; 115 if (0x59 < data[RTC_SEC] || 0x09 < (data[RTC_SEC] & 0x0F) || 116 0x59 < min || 0x09 < (min & 0x0F) || 117 0x23 < data[RTC_HOUR] || 0x09 < (data[RTC_HOUR] & 0x0F) || 118 0x07 < data[RTC_DAY] || 0x00 == data[RTC_DAY] || 119 0x12 < month || 120 0x99 < years || 0x09 < (years & 0x0F) || 121 daysInMonth[month] < date || 0x09 < (date & 0x0F) || 0x00 == date || 122 (0x29 == date && 0x02 == month && 123 ((0x00 != (years & 0x03)) || 124 (0x00 == years && 0x00 != (data[RTC_MONTH] & 0xC0))))) { 125 printf("Resetting M41T60 RTC clock.\n"); 126 /* 127 * Set to 00:00:00 1900-01-01 (Monday) 128 */ 129 data[RTC_SEC] = 0x00; 130 data[RTC_MIN] &= 0x80; /* preserve OFIE bit */ 131 data[RTC_HOUR] = 0x00; 132 data[RTC_DAY] = 0x02; 133 data[RTC_DATE] = 0x01; 134 data[RTC_MONTH] = 0xC1; 135 data[RTC_YEAR] = 0x00; 136 data[RTC_CTRL] &= 0x7F; /* reset OUT bit */ 137 138 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 139 printf("I2C write failed in rtc_validate()\n"); 140 return 0; 141 } 142 } 143 return data; 144 } 145 146 int rtc_get(struct rtc_time *tmp) 147 { 148 uchar const *const data = rtc_validate(); 149 150 if (!data) 151 return -1; 152 153 tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F); 154 tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F); 155 tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F); 156 tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F); 157 tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F); 158 tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]); 159 tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1; 160 tmp->tm_yday = 0; 161 tmp->tm_isdst = 0; 162 163 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 164 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 165 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 166 167 return 0; 168 } 169 170 int rtc_set(struct rtc_time *tmp) 171 { 172 uchar *const data = rtc_validate(); 173 174 if (!data) 175 return -1; 176 177 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 178 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 179 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 180 181 data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F); 182 data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F); 183 data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F; 184 data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F; 185 data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F; 186 data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100); 187 data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6; 188 data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07; 189 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, RTC_REG_CNT)) { 190 printf("I2C write failed in rtc_set()\n"); 191 return -1; 192 } 193 194 return 0; 195 } 196 197 void rtc_reset(void) 198 { 199 uchar *const data = rtc_validate(); 200 char const *const s = env_get("rtccal"); 201 202 if (!data) 203 return; 204 205 rtc_dump("begin reset"); 206 /* 207 * If environmental variable "rtccal" is present, it must be a hex value 208 * between 0x00 and 0x3F, inclusive. The five least-significan bits 209 * represent the calibration magnitude, and the sixth bit the sign bit. 210 * If these do not match the contents of the hardware register, that 211 * register is updated. The value 0x00 imples no correction. Consult 212 * the M41T60 documentation for further details. 213 */ 214 if (s) { 215 unsigned long const l = simple_strtoul(s, 0, 16); 216 217 if (l <= 0x3F) { 218 if ((data[RTC_CTRL] & 0x3F) != l) { 219 printf("Setting RTC calibration to 0x%02lX\n", 220 l); 221 data[RTC_CTRL] &= 0xC0; 222 data[RTC_CTRL] |= (uchar) l; 223 } 224 } else 225 printf("environment parameter \"rtccal\" not valid: " 226 "ignoring\n"); 227 } 228 /* 229 * Turn off frequency test. 230 */ 231 data[RTC_CTRL] &= 0xBF; 232 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CTRL, 1, data + RTC_CTRL, 1)) { 233 printf("I2C write failed in rtc_reset()\n"); 234 return; 235 } 236 rtc_dump("end reset"); 237 } 238