drivers/rtc/m41t11.c

   1 /*
   2  * (C) Copyright 2002
   3  * Andrew May, Viasat Inc, amay@viasat.com
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation; either version 2 of
   8  * the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  18  * MA 02111-1307 USA
  19  */
  20
  21 /*
  22  * M41T11 Serial Access Timekeeper(R) SRAM
  23  * can you believe a trademark on that?
  24  */
  25
  26 /* #define DEBUG 1 */
  27
  28 #include <common.h>
  29 #include <command.h>
  30 #include <rtc.h>
  31 #include <i2c.h>
  32
  33 /*
  34         I Don't have an example config file but this
  35         is what should be done.
  36
  37 #define CONFIG_RTC_M41T11 1
  38 #define CFG_I2C_RTC_ADDR 0x68
  39 #if 0
  40 #define CFG_M41T11_EXT_CENTURY_DATA
  41 #else
  42 #define CFG_M41T11_BASE_YEAR 2000
  43 #endif
  44 */
  45
  46 #if defined(CONFIG_RTC_M41T11) && defined(CFG_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE)
  47
  48 static unsigned bcd2bin (uchar n)
  49 {
  50         return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
  51 }
  52
  53 static unsigned char bin2bcd (unsigned int n)
  54 {
  55         return (((n / 10) << 4) | (n % 10));
  56 }
  57
  58
  59 /* ------------------------------------------------------------------------- */
  60 /*
  61   these are simple defines for the chip local to here so they aren't too
  62   verbose
  63   DAY/DATE aren't nice but that is how they are on the data sheet
  64 */
  65 #define RTC_SEC_ADDR       0x0
  66 #define RTC_MIN_ADDR       0x1
  67 #define RTC_HOUR_ADDR      0x2
  68 #define RTC_DAY_ADDR       0x3
  69 #define RTC_DATE_ADDR      0x4
  70 #define RTC_MONTH_ADDR     0x5
  71 #define RTC_YEARS_ADDR     0x6
  72
  73 #define RTC_REG_CNT        7
  74
  75 #define RTC_CONTROL_ADDR   0x7
  76
  77
  78 #ifndef CFG_M41T11_EXT_CENTURY_DATA
  79
  80 #define REG_CNT            (RTC_REG_CNT+1)
  81
  82 /*
  83   you only get 00-99 for the year we will asume you
  84   want from the year 2000 if you don't set the config
  85 */
  86 #ifndef CFG_M41T11_BASE_YEAR
  87 #define CFG_M41T11_BASE_YEAR 2000
  88 #endif
  89
  90 #else
  91 /* we will store extra year info in byte 9*/
  92 #define M41T11_YEAR_DATA   0x8
  93 #define M41T11_YEAR_SIZE   1
  94 #define REG_CNT            (RTC_REG_CNT+1+M41T11_YEAR_SIZE)
  95 #endif
  96
  97 #define M41T11_STORAGE_SZ  (64-REG_CNT)
  98
  99 int rtc_get (struct rtc_time *tmp)
 100 {
 101         int rel = 0;
 102         uchar data[RTC_REG_CNT];
 103
 104         i2c_read(CFG_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
 105
 106         if( data[RTC_SEC_ADDR] & 0x80 ){
 107                 printf( "m41t11 RTC Clock stopped!!!\n" );
 108                 rel = -1;
 109         }
 110         tmp->tm_sec  = bcd2bin (data[RTC_SEC_ADDR]  & 0x7F);
 111         tmp->tm_min  = bcd2bin (data[RTC_MIN_ADDR]  & 0x7F);
 112         tmp->tm_hour = bcd2bin (data[RTC_HOUR_ADDR] & 0x3F);
 113         tmp->tm_mday = bcd2bin (data[RTC_DATE_ADDR] & 0x3F);
 114         tmp->tm_mon  = bcd2bin (data[RTC_MONTH_ADDR]& 0x1F);
 115 #ifndef CFG_M41T11_EXT_CENTURY_DATA
 116         tmp->tm_year = CFG_M41T11_BASE_YEAR
 117                 + bcd2bin(data[RTC_YEARS_ADDR])
 118                 + ((data[RTC_HOUR_ADDR]&0x40) ? 100 : 0);
 119 #else
 120         {
 121                 unsigned char cent;
 122                 i2c_read(CFG_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
 123                 if( !(data[RTC_HOUR_ADDR] & 0x80) ){
 124                         printf( "m41t11 RTC: cann't keep track of years without CEB set\n" );
 125                         rel = -1;
 126                 }
 127                 if( (cent & 0x1) != ((data[RTC_HOUR_ADDR]&0x40)>>7) ){
 128                         /*century flip store off new year*/
 129                         cent += 1;
 130                         i2c_write(CFG_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
 131                 }
 132                 tmp->tm_year =((int)cent*100)+bcd2bin(data[RTC_YEARS_ADDR]);
 133         }
 134 #endif
 135         tmp->tm_wday = bcd2bin (data[RTC_DAY_ADDR]  & 0x07);
 136         tmp->tm_yday = 0;
 137         tmp->tm_isdst= 0;
 138
 139         debug ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 140                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 141                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 142
 143         return rel;
 144 }
 145
 146 void rtc_set (struct rtc_time *tmp)
 147 {
 148         uchar data[RTC_REG_CNT];
 149
 150         debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 151                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 152                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 153
 154         data[RTC_SEC_ADDR]    = bin2bcd(tmp->tm_sec) &  0x7F;/*just in case*/
 155         data[RTC_MIN_ADDR]    = bin2bcd(tmp->tm_min);
 156         data[RTC_HOUR_ADDR]   = bin2bcd(tmp->tm_hour) & 0x3F;/*handle cent stuff later*/
 157         data[RTC_DATE_ADDR]   = bin2bcd(tmp->tm_mday) & 0x3F;
 158         data[RTC_MONTH_ADDR]  = bin2bcd(tmp->tm_mon);
 159         data[RTC_DAY_ADDR]    = bin2bcd(tmp->tm_wday) & 0x07;
 160
 161         data[RTC_HOUR_ADDR]   |= 0x80;/*we will always use CEB*/
 162
 163         data[RTC_YEARS_ADDR]  = bin2bcd(tmp->tm_year%100);/*same thing either way*/
 164 #ifndef CFG_M41T11_EXT_CENTURY_DATA
 165         if( ((tmp->tm_year - CFG_M41T11_BASE_YEAR) > 200) ||
 166             (tmp->tm_year < CFG_M41T11_BASE_YEAR) ){
 167                 printf( "m41t11 RTC setting year out of range!!need recompile\n" );
 168         }
 169         data[RTC_HOUR_ADDR] |= (tmp->tm_year - CFG_M41T11_BASE_YEAR) > 100 ? 0x40 : 0;
 170 #else
 171         {
 172                 unsigned char cent;
 173                 cent = tmp->tm_year ? tmp->tm_year / 100 : 0;
 174                 data[RTC_HOUR_ADDR] |= (cent & 0x1) ? 0x40 : 0;
 175                 i2c_write(CFG_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
 176         }
 177 #endif
 178         i2c_write(CFG_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
 179 }
 180
 181 void rtc_reset (void)
 182 {
 183         unsigned char val;
 184         /* clear all control & status registers */
 185         i2c_read(CFG_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, 1);
 186         val = val & 0x7F;/*make sure we are running*/
 187         i2c_write(CFG_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, RTC_REG_CNT);
 188
 189         i2c_read(CFG_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
 190         val = val & 0x3F;/*turn off freq test keep calibration*/
 191         i2c_write(CFG_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
 192 }
 193
 194 int rtc_store(int addr, unsigned char* data, int size)
 195 {
 196         /*don't let things wrap onto the time on a write*/
 197         if( (addr+size) >= M41T11_STORAGE_SZ )
 198                 return 1;
 199         return i2c_write( CFG_I2C_RTC_ADDR, REG_CNT+addr, 1, data, size );
 200 }
 201
 202 int rtc_recall(int addr, unsigned char* data, int size)
 203 {
 204         return i2c_read( CFG_I2C_RTC_ADDR, REG_CNT+addr, 1, data, size );
 205 }
 206
 207 #endif