1 /* 2 * (C) Copyright 2007 3 * Larry Johnson, lrj@acm.org 4 * 5 * based on rtc/m41t11.c which is ... 6 * 7 * (C) Copyright 2002 8 * Andrew May, Viasat Inc, amay@viasat.com 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 of 13 * the License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 23 * MA 02111-1307 USA 24 */ 25 26 /* 27 * STMicroelectronics M41T60 serial access real-time clock 28 */ 29 30 /* #define DEBUG 1 */ 31 32 #include <common.h> 33 #include <command.h> 34 #include <rtc.h> 35 #include <i2c.h> 36 37 #if defined(CONFIG_SYS_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE) 38 39 /* 40 * Convert between century and "century bits" (CB1 and CB0). These routines 41 * assume years are in the range 1900 - 2299. 42 */ 43 44 static unsigned char year2cb(unsigned const year) 45 { 46 if (year < 1900 || year >= 2300) 47 printf("M41T60 RTC: year %d out of range\n", year); 48 49 return (year / 100) & 0x3; 50 } 51 52 static unsigned cb2year(unsigned const cb) 53 { 54 return 1900 + 100 * ((cb + 1) & 0x3); 55 } 56 57 /* 58 * These are simple defines for the chip local to here so they aren't too 59 * verbose. DAY/DATE aren't nice but that is how they are on the data sheet. 60 */ 61 #define RTC_SEC 0x0 62 #define RTC_MIN 0x1 63 #define RTC_HOUR 0x2 64 #define RTC_DAY 0x3 65 #define RTC_DATE 0x4 66 #define RTC_MONTH 0x5 67 #define RTC_YEAR 0x6 68 69 #define RTC_REG_CNT 7 70 71 #define RTC_CTRL 0x7 72 73 #if defined(DEBUG) 74 static void rtc_dump(char const *const label) 75 { 76 uchar data[8]; 77 78 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 79 printf("I2C read failed in rtc_dump()\n"); 80 return; 81 } 82 printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n", 83 label, data[0], data[1], data[2], data[3], 84 data[4], data[5], data[6], data[7]); 85 } 86 #else 87 #define rtc_dump(label) 88 #endif 89 90 static uchar *rtc_validate(void) 91 { 92 /* 93 * This routine uses the OUT bit and the validity of the time values to 94 * determine whether there has been an initial power-up since the last 95 * time the routine was run. It assumes that the OUT bit is not being 96 * used for any other purpose. 97 */ 98 static const uchar daysInMonth[0x13] = { 99 0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31, 100 0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 101 0x31, 0x30, 0x31 102 }; 103 static uchar data[8]; 104 uchar min, date, month, years; 105 106 rtc_dump("begin validate"); 107 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 108 printf("I2C read failed in rtc_validate()\n"); 109 return 0; 110 } 111 /* 112 * If the OUT bit is "1", there has been a loss of power, so stop the 113 * oscillator so it can be "kick-started" as per data sheet. 114 */ 115 if (0x00 != (data[RTC_CTRL] & 0x80)) { 116 printf("M41T60 RTC clock lost power.\n"); 117 data[RTC_SEC] = 0x80; 118 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC, 1, data, 1)) { 119 printf("I2C write failed in rtc_validate()\n"); 120 return 0; 121 } 122 } 123 /* 124 * If the oscillator is stopped or the date is invalid, then reset the 125 * OUT bit to "0", reset the date registers, and start the oscillator. 126 */ 127 min = data[RTC_MIN] & 0x7F; 128 date = data[RTC_DATE]; 129 month = data[RTC_MONTH] & 0x3F; 130 years = data[RTC_YEAR]; 131 if (0x59 < data[RTC_SEC] || 0x09 < (data[RTC_SEC] & 0x0F) || 132 0x59 < min || 0x09 < (min & 0x0F) || 133 0x23 < data[RTC_HOUR] || 0x09 < (data[RTC_HOUR] & 0x0F) || 134 0x07 < data[RTC_DAY] || 0x00 == data[RTC_DAY] || 135 0x12 < month || 136 0x99 < years || 0x09 < (years & 0x0F) || 137 daysInMonth[month] < date || 0x09 < (date & 0x0F) || 0x00 == date || 138 (0x29 == date && 0x02 == month && 139 ((0x00 != (years & 0x03)) || 140 (0x00 == years && 0x00 != (data[RTC_MONTH] & 0xC0))))) { 141 printf("Resetting M41T60 RTC clock.\n"); 142 /* 143 * Set to 00:00:00 1900-01-01 (Monday) 144 */ 145 data[RTC_SEC] = 0x00; 146 data[RTC_MIN] &= 0x80; /* preserve OFIE bit */ 147 data[RTC_HOUR] = 0x00; 148 data[RTC_DAY] = 0x02; 149 data[RTC_DATE] = 0x01; 150 data[RTC_MONTH] = 0xC1; 151 data[RTC_YEAR] = 0x00; 152 data[RTC_CTRL] &= 0x7F; /* reset OUT bit */ 153 154 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 155 printf("I2C write failed in rtc_validate()\n"); 156 return 0; 157 } 158 } 159 return data; 160 } 161 162 int rtc_get(struct rtc_time *tmp) 163 { 164 uchar const *const data = rtc_validate(); 165 166 if (!data) 167 return -1; 168 169 tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F); 170 tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F); 171 tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F); 172 tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F); 173 tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F); 174 tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]); 175 tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1; 176 tmp->tm_yday = 0; 177 tmp->tm_isdst = 0; 178 179 debug("Get 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 return 0; 184 } 185 186 int rtc_set(struct rtc_time *tmp) 187 { 188 uchar *const data = rtc_validate(); 189 190 if (!data) 191 return -1; 192 193 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 194 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 195 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 196 197 data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F); 198 data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F); 199 data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F; 200 data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F; 201 data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F; 202 data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100); 203 data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6; 204 data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07; 205 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, RTC_REG_CNT)) { 206 printf("I2C write failed in rtc_set()\n"); 207 return -1; 208 } 209 210 return 0; 211 } 212 213 void rtc_reset(void) 214 { 215 uchar *const data = rtc_validate(); 216 char const *const s = getenv("rtccal"); 217 218 if (!data) 219 return; 220 221 rtc_dump("begin reset"); 222 /* 223 * If environmental variable "rtccal" is present, it must be a hex value 224 * between 0x00 and 0x3F, inclusive. The five least-significan bits 225 * represent the calibration magnitude, and the sixth bit the sign bit. 226 * If these do not match the contents of the hardware register, that 227 * register is updated. The value 0x00 imples no correction. Consult 228 * the M41T60 documentation for further details. 229 */ 230 if (s) { 231 unsigned long const l = simple_strtoul(s, 0, 16); 232 233 if (l <= 0x3F) { 234 if ((data[RTC_CTRL] & 0x3F) != l) { 235 printf("Setting RTC calibration to 0x%02lX\n", 236 l); 237 data[RTC_CTRL] &= 0xC0; 238 data[RTC_CTRL] |= (uchar) l; 239 } 240 } else 241 printf("environment parameter \"rtccal\" not valid: " 242 "ignoring\n"); 243 } 244 /* 245 * Turn off frequency test. 246 */ 247 data[RTC_CTRL] &= 0xBF; 248 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CTRL, 1, data + RTC_CTRL, 1)) { 249 printf("I2C write failed in rtc_reset()\n"); 250 return; 251 } 252 rtc_dump("end reset"); 253 } 254 #endif /* CONFIG_RTC_M41T60 && CONFIG_SYS_I2C_RTC_ADDR && CONFIG_CMD_DATE */ 255