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 static unsigned bcd2bin(uchar n) 40 { 41 return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F)); 42 } 43 44 static unsigned char bin2bcd(unsigned int n) 45 { 46 return (((n / 10) << 4) | (n % 10)); 47 } 48 49 /* 50 * Convert between century and "century bits" (CB1 and CB0). These routines 51 * assume years are in the range 1900 - 2299. 52 */ 53 54 static unsigned char year2cb(unsigned const year) 55 { 56 if (year < 1900 || year >= 2300) 57 printf("M41T60 RTC: year %d out of range\n", year); 58 59 return (year / 100) & 0x3; 60 } 61 62 static unsigned cb2year(unsigned const cb) 63 { 64 return 1900 + 100 * ((cb + 1) & 0x3); 65 } 66 67 /* 68 * These are simple defines for the chip local to here so they aren't too 69 * verbose. DAY/DATE aren't nice but that is how they are on the data sheet. 70 */ 71 #define RTC_SEC 0x0 72 #define RTC_MIN 0x1 73 #define RTC_HOUR 0x2 74 #define RTC_DAY 0x3 75 #define RTC_DATE 0x4 76 #define RTC_MONTH 0x5 77 #define RTC_YEAR 0x6 78 79 #define RTC_REG_CNT 7 80 81 #define RTC_CTRL 0x7 82 83 #if defined(DEBUG) 84 static void rtc_dump(char const *const label) 85 { 86 uchar data[8]; 87 88 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 89 printf("I2C read failed in rtc_dump()\n"); 90 return; 91 } 92 printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n", 93 label, data[0], data[1], data[2], data[3], 94 data[4], data[5], data[6], data[7]); 95 } 96 #else 97 #define rtc_dump(label) 98 #endif 99 100 static uchar *rtc_validate(void) 101 { 102 /* 103 * This routine uses the OUT bit and the validity of the time values to 104 * determine whether there has been an initial power-up since the last 105 * time the routine was run. It assumes that the OUT bit is not being 106 * used for any other purpose. 107 */ 108 static const uchar daysInMonth[0x13] = { 109 0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31, 110 0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 111 0x31, 0x30, 0x31 112 }; 113 static uchar data[8]; 114 uchar min, date, month, years; 115 116 rtc_dump("begin validate"); 117 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 118 printf("I2C read failed in rtc_validate()\n"); 119 return 0; 120 } 121 /* 122 * If the OUT bit is "1", there has been a loss of power, so stop the 123 * oscillator so it can be "kick-started" as per data sheet. 124 */ 125 if (0x00 != (data[RTC_CTRL] & 0x80)) { 126 printf("M41T60 RTC clock lost power.\n"); 127 data[RTC_SEC] = 0x80; 128 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC, 1, data, 1)) { 129 printf("I2C write failed in rtc_validate()\n"); 130 return 0; 131 } 132 } 133 /* 134 * If the oscillator is stopped or the date is invalid, then reset the 135 * OUT bit to "0", reset the date registers, and start the oscillator. 136 */ 137 min = data[RTC_MIN] & 0x7F; 138 date = data[RTC_DATE]; 139 month = data[RTC_MONTH] & 0x3F; 140 years = data[RTC_YEAR]; 141 if (0x59 < data[RTC_SEC] || 0x09 < (data[RTC_SEC] & 0x0F) || 142 0x59 < min || 0x09 < (min & 0x0F) || 143 0x23 < data[RTC_HOUR] || 0x09 < (data[RTC_HOUR] & 0x0F) || 144 0x07 < data[RTC_DAY] || 0x00 == data[RTC_DAY] || 145 0x12 < month || 146 0x99 < years || 0x09 < (years & 0x0F) || 147 daysInMonth[month] < date || 0x09 < (date & 0x0F) || 0x00 == date || 148 (0x29 == date && 0x02 == month && 149 ((0x00 != (years & 0x03)) || 150 (0x00 == years && 0x00 != (data[RTC_MONTH] & 0xC0))))) { 151 printf("Resetting M41T60 RTC clock.\n"); 152 /* 153 * Set to 00:00:00 1900-01-01 (Monday) 154 */ 155 data[RTC_SEC] = 0x00; 156 data[RTC_MIN] &= 0x80; /* preserve OFIE bit */ 157 data[RTC_HOUR] = 0x00; 158 data[RTC_DAY] = 0x02; 159 data[RTC_DATE] = 0x01; 160 data[RTC_MONTH] = 0xC1; 161 data[RTC_YEAR] = 0x00; 162 data[RTC_CTRL] &= 0x7F; /* reset OUT bit */ 163 164 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 165 printf("I2C write failed in rtc_validate()\n"); 166 return 0; 167 } 168 } 169 return data; 170 } 171 172 int rtc_get(struct rtc_time *tmp) 173 { 174 uchar const *const data = rtc_validate(); 175 176 if (!data) 177 return -1; 178 179 tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F); 180 tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F); 181 tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F); 182 tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F); 183 tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F); 184 tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]); 185 tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1; 186 tmp->tm_yday = 0; 187 tmp->tm_isdst = 0; 188 189 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 190 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 191 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 192 193 return 0; 194 } 195 196 int rtc_set(struct rtc_time *tmp) 197 { 198 uchar *const data = rtc_validate(); 199 200 if (!data) 201 return -1; 202 203 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 204 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 205 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 206 207 data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F); 208 data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F); 209 data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F; 210 data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F; 211 data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F; 212 data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100); 213 data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6; 214 data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07; 215 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, data, RTC_REG_CNT)) { 216 printf("I2C write failed in rtc_set()\n"); 217 return -1; 218 } 219 220 return 0; 221 } 222 223 void rtc_reset(void) 224 { 225 uchar *const data = rtc_validate(); 226 char const *const s = getenv("rtccal"); 227 228 if (!data) 229 return; 230 231 rtc_dump("begin reset"); 232 /* 233 * If environmental variable "rtccal" is present, it must be a hex value 234 * between 0x00 and 0x3F, inclusive. The five least-significan bits 235 * represent the calibration magnitude, and the sixth bit the sign bit. 236 * If these do not match the contents of the hardware register, that 237 * register is updated. The value 0x00 imples no correction. Consult 238 * the M41T60 documentation for further details. 239 */ 240 if (s) { 241 unsigned long const l = simple_strtoul(s, 0, 16); 242 243 if (l <= 0x3F) { 244 if ((data[RTC_CTRL] & 0x3F) != l) { 245 printf("Setting RTC calibration to 0x%02lX\n", 246 l); 247 data[RTC_CTRL] &= 0xC0; 248 data[RTC_CTRL] |= (uchar) l; 249 } 250 } else 251 printf("environment parameter \"rtccal\" not valid: " 252 "ignoring\n"); 253 } 254 /* 255 * Turn off frequency test. 256 */ 257 data[RTC_CTRL] &= 0xBF; 258 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CTRL, 1, data + RTC_CTRL, 1)) { 259 printf("I2C write failed in rtc_reset()\n"); 260 return; 261 } 262 rtc_dump("end reset"); 263 } 264 #endif /* CONFIG_RTC_M41T60 && CONFIG_SYS_I2C_RTC_ADDR && CONFIG_CMD_DATE */ 265