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 #if defined(CONFIG_SYS_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE) 24 25 /* 26 * Convert between century and "century bits" (CB1 and CB0). These routines 27 * assume years are in the range 1900 - 2299. 28 */ 29 30 static unsigned char year2cb(unsigned const year) 31 { 32 if (year < 1900 || year >= 2300) 33 printf("M41T60 RTC: year %d out of range\n", year); 34 35 return (year / 100) & 0x3; 36 } 37 38 static unsigned cb2year(unsigned const cb) 39 { 40 return 1900 + 100 * ((cb + 1) & 0x3); 41 } 42 43 /* 44 * These are simple defines for the chip local to here so they aren't too 45 * verbose. DAY/DATE aren't nice but that is how they are on the data sheet. 46 */ 47 #define RTC_SEC 0x0 48 #define RTC_MIN 0x1 49 #define RTC_HOUR 0x2 50 #define RTC_DAY 0x3 51 #define RTC_DATE 0x4 52 #define RTC_MONTH 0x5 53 #define RTC_YEAR 0x6 54 55 #define RTC_REG_CNT 7 56 57 #define RTC_CTRL 0x7 58 59 #if defined(DEBUG) 60 static void rtc_dump(char const *const label) 61 { 62 uchar data[8]; 63 64 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 65 printf("I2C read failed in rtc_dump()\n"); 66 return; 67 } 68 printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n", 69 label, data[0], data[1], data[2], data[3], 70 data[4], data[5], data[6], data[7]); 71 } 72 #else 73 #define rtc_dump(label) 74 #endif 75 76 static uchar *rtc_validate(void) 77 { 78 /* 79 * This routine uses the OUT bit and the validity of the time values to 80 * determine whether there has been an initial power-up since the last 81 * time the routine was run. It assumes that the OUT bit is not being 82 * used for any other purpose. 83 */ 84 static const uchar daysInMonth[0x13] = { 85 0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31, 86 0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 87 0x31, 0x30, 0x31 88 }; 89 static uchar data[8]; 90 uchar min, date, month, years; 91 92 rtc_dump("begin validate"); 93 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 94 printf("I2C read failed in rtc_validate()\n"); 95 return 0; 96 } 97 /* 98 * If the OUT bit is "1", there has been a loss of power, so stop the 99 * oscillator so it can be "kick-started" as per data sheet. 100 */ 101 if (0x00 != (data[RTC_CTRL] & 0x80)) { 102 printf("M41T60 RTC clock lost power.\n"); 103 data[RTC_SEC] = 0x80; 104 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC, 1, data, 1)) { 105 printf("I2C write failed in rtc_validate()\n"); 106 return 0; 107 } 108 } 109 /* 110 * If the oscillator is stopped or the date is invalid, then reset the 111 * OUT bit to "0", reset the date registers, and start the oscillator. 112 */ 113 min = data[RTC_MIN] & 0x7F; 114 date = data[RTC_DATE]; 115 month = data[RTC_MONTH] & 0x3F; 116 years = data[RTC_YEAR]; 117 if (0x59 < data[RTC_SEC] || 0x09 < (data[RTC_SEC] & 0x0F) || 118 0x59 < min || 0x09 < (min & 0x0F) || 119 0x23 < data[RTC_HOUR] || 0x09 < (data[RTC_HOUR] & 0x0F) || 120 0x07 < data[RTC_DAY] || 0x00 == data[RTC_DAY] || 121 0x12 < month || 122 0x99 < years || 0x09 < (years & 0x0F) || 123 daysInMonth[month] < date || 0x09 < (date & 0x0F) || 0x00 == date || 124 (0x29 == date && 0x02 == month && 125 ((0x00 != (years & 0x03)) || 126 (0x00 == years && 0x00 != (data[RTC_MONTH] & 0xC0))))) { 127 printf("Resetting M41T60 RTC clock.\n"); 128 /* 129 * Set to 00:00:00 1900-01-01 (Monday) 130 */ 131 data[RTC_SEC] = 0x00; 132 data[RTC_MIN] &= 0x80; /* preserve OFIE bit */ 133 data[RTC_HOUR] = 0x00; 134 data[RTC_DAY] = 0x02; 135 data[RTC_DATE] = 0x01; 136 data[RTC_MONTH] = 0xC1; 137 data[RTC_YEAR] = 0x00; 138 data[RTC_CTRL] &= 0x7F; /* reset OUT bit */ 139 140 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 141 printf("I2C write failed in rtc_validate()\n"); 142 return 0; 143 } 144 } 145 return data; 146 } 147 148 int rtc_get(struct rtc_time *tmp) 149 { 150 uchar const *const data = rtc_validate(); 151 152 if (!data) 153 return -1; 154 155 tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F); 156 tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F); 157 tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F); 158 tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F); 159 tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F); 160 tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]); 161 tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1; 162 tmp->tm_yday = 0; 163 tmp->tm_isdst = 0; 164 165 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 166 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 167 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 168 169 return 0; 170 } 171 172 int rtc_set(struct rtc_time *tmp) 173 { 174 uchar *const data = rtc_validate(); 175 176 if (!data) 177 return -1; 178 179 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 180 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 181 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 182 183 data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F); 184 data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F); 185 data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F; 186 data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F; 187 data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F; 188 data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100); 189 data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6; 190 data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07; 191 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, RTC_REG_CNT)) { 192 printf("I2C write failed in rtc_set()\n"); 193 return -1; 194 } 195 196 return 0; 197 } 198 199 void rtc_reset(void) 200 { 201 uchar *const data = rtc_validate(); 202 char const *const s = env_get("rtccal"); 203 204 if (!data) 205 return; 206 207 rtc_dump("begin reset"); 208 /* 209 * If environmental variable "rtccal" is present, it must be a hex value 210 * between 0x00 and 0x3F, inclusive. The five least-significan bits 211 * represent the calibration magnitude, and the sixth bit the sign bit. 212 * If these do not match the contents of the hardware register, that 213 * register is updated. The value 0x00 imples no correction. Consult 214 * the M41T60 documentation for further details. 215 */ 216 if (s) { 217 unsigned long const l = simple_strtoul(s, 0, 16); 218 219 if (l <= 0x3F) { 220 if ((data[RTC_CTRL] & 0x3F) != l) { 221 printf("Setting RTC calibration to 0x%02lX\n", 222 l); 223 data[RTC_CTRL] &= 0xC0; 224 data[RTC_CTRL] |= (uchar) l; 225 } 226 } else 227 printf("environment parameter \"rtccal\" not valid: " 228 "ignoring\n"); 229 } 230 /* 231 * Turn off frequency test. 232 */ 233 data[RTC_CTRL] &= 0xBF; 234 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CTRL, 1, data + RTC_CTRL, 1)) { 235 printf("I2C write failed in rtc_reset()\n"); 236 return; 237 } 238 rtc_dump("end reset"); 239 } 240 #endif /* CONFIG_RTC_M41T60 && CONFIG_SYS_I2C_RTC_ADDR && CONFIG_CMD_DATE */ 241