drivers/rtc/rs5c372.c

   1 /*
   2  * rs5c372.c
   3  *
   4  * Device driver for Ricoh's Real Time Controller RS5C372A.
   5  *
   6  * Copyright (C) 2004 Gary Jennejohn garyj@denx.de
   7  *
   8  * Based in part in ds1307.c -
   9  * (C) Copyright 2001, 2002, 2003
  10  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  11  * Keith Outwater, keith_outwater@mvis.com`
  12  * Steven Scholz, steven.scholz@imc-berlin.de
  13  *
  14  * See file CREDITS for list of people who contributed to this
  15  * project.
  16  *
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License version 2 as
  19  * published by the Free Software Foundation.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  * GNU General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program; if not, write to the Free Software
  28  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  29  * MA 02111-1307 USA
  30  */
  31
  32 #include <common.h>
  33 #include <command.h>
  34 #include <rtc.h>
  35 #include <i2c.h>
  36
  37 #if defined(CONFIG_RTC_RS5C372A) && defined(CONFIG_CMD_DATE)
  38 /*
  39  * Reads are always done starting with register 15, which requires some
  40  * jumping-through-hoops to access the data correctly.
  41  *
  42  * Writes are always done starting with register 0.
  43  */
  44
  45 #define DEBUG 0
  46
  47 #if DEBUG
  48 static unsigned int rtc_debug = DEBUG;
  49 #else
  50 #define rtc_debug 0     /* gcc will remove all the debug code for us */
  51 #endif
  52
  53 #ifndef CFG_I2C_RTC_ADDR
  54 #define CFG_I2C_RTC_ADDR 0x32
  55 #endif
  56
  57 #define RS5C372_RAM_SIZE 0x10
  58 #define RATE_32000HZ    0x80    /* Rate Select 32.000KHz */
  59 #define RATE_32768HZ    0x00    /* Rate Select 32.768KHz */
  60
  61 #define STATUS_XPT  0x10    /* data invalid because voltage was 0 */
  62
  63 #define USE_24HOUR_MODE 0x20
  64 #define TWELVE_HOUR_MODE(n) ((((n) >> 5) & 1) == 0)
  65 #define HOURS_AP(n)     (((n) >> 5) & 1)
  66 #define HOURS_12(n)     bcd2bin((n) & 0x1F)
  67 #define HOURS_24(n)     bcd2bin((n) & 0x3F)
  68
  69
  70 static uchar bin2bcd (unsigned int n);
  71 static unsigned bcd2bin (uchar c);
  72
  73 static int setup_done = 0;
  74
  75 static int
  76 rs5c372_readram(unsigned char *buf, int len)
  77 {
  78         int ret;
  79
  80         ret = i2c_read(CFG_I2C_RTC_ADDR, 0, 0, buf, len);
  81         if (ret != 0) {
  82                 printf("%s: failed to read\n", __FUNCTION__);
  83                 return ret;
  84         }
  85
  86         if (buf[0] & STATUS_XPT)
  87                 printf("### Warning: RTC lost power\n");
  88
  89         return ret;
  90 }
  91
  92 static void
  93 rs5c372_enable(void)
  94 {
  95         unsigned char buf[RS5C372_RAM_SIZE + 1];
  96         int ret;
  97
  98         /* note that this returns reg. 15 in buf[1] */
  99         ret = rs5c372_readram(&buf[1], RS5C372_RAM_SIZE);
 100         if (ret != 0) {
 101                 printf("%s: failed\n", __FUNCTION__);
 102                 return;
 103         }
 104
 105         buf[0] = 0;
 106         /* we want to start writing at register 0 so we have to copy the */
 107         /* register contents up one slot */
 108         for (ret = 2; ret < 9; ret++)
 109                 buf[ret - 1] = buf[ret];
 110         /* registers 0 to 6 (time values) are not touched */
 111         buf[8] = RATE_32768HZ; /* reg. 7 */
 112         buf[9] = 0; /* reg. 8 */
 113         buf[10] = 0; /* reg. 9 */
 114         buf[11] = 0; /* reg. 10 */
 115         buf[12] = 0; /* reg. 11 */
 116         buf[13] = 0; /* reg. 12 */
 117         buf[14] = 0; /* reg. 13 */
 118         buf[15] = 0; /* reg. 14 */
 119         buf[16] = USE_24HOUR_MODE; /* reg. 15 */
 120         ret = i2c_write(CFG_I2C_RTC_ADDR, 0, 0, buf, RS5C372_RAM_SIZE+1);
 121         if (ret != 0) {
 122                 printf("%s: failed\n", __FUNCTION__);
 123                 return;
 124         }
 125         setup_done = 1;
 126
 127         return;
 128 }
 129
 130 static void
 131 rs5c372_convert_to_time(struct rtc_time *dt, unsigned char *buf)
 132 {
 133         /* buf[0] is register 15 */
 134         dt->tm_sec = bcd2bin(buf[1]);
 135         dt->tm_min = bcd2bin(buf[2]);
 136
 137         if (TWELVE_HOUR_MODE(buf[0])) {
 138                 dt->tm_hour = HOURS_12(buf[3]);
 139                 if (HOURS_AP(buf[3])) /* PM */
 140                         dt->tm_hour += 12;
 141         } else /* 24-hour-mode */
 142                 dt->tm_hour = HOURS_24(buf[3]);
 143
 144         dt->tm_mday = bcd2bin(buf[5]);
 145         dt->tm_mon = bcd2bin(buf[6]);
 146         dt->tm_year = bcd2bin(buf[7]);
 147         if (dt->tm_year >= 70)
 148                 dt->tm_year += 1900;
 149         else
 150                 dt->tm_year += 2000;
 151         /* 0 is Sunday */
 152         dt->tm_wday = bcd2bin(buf[4] & 0x07);
 153         dt->tm_yday = 0;
 154         dt->tm_isdst= 0;
 155
 156         if(rtc_debug > 2) {
 157                 printf("rs5c372_convert_to_time: year = %d\n", dt->tm_year);
 158                 printf("rs5c372_convert_to_time: mon  = %d\n", dt->tm_mon);
 159                 printf("rs5c372_convert_to_time: mday = %d\n", dt->tm_mday);
 160                 printf("rs5c372_convert_to_time: hour = %d\n", dt->tm_hour);
 161                 printf("rs5c372_convert_to_time: min  = %d\n", dt->tm_min);
 162                 printf("rs5c372_convert_to_time: sec  = %d\n", dt->tm_sec);
 163         }
 164 }
 165
 166 /*
 167  * Get the current time from the RTC
 168  */
 169 int
 170 rtc_get (struct rtc_time *tmp)
 171 {
 172         unsigned char buf[RS5C372_RAM_SIZE];
 173         int ret;
 174
 175         if (!setup_done)
 176                 rs5c372_enable();
 177
 178         if (!setup_done)
 179                 return -1;
 180
 181         memset(buf, 0, sizeof(buf));
 182
 183         /* note that this returns reg. 15 in buf[0] */
 184         ret = rs5c372_readram(buf, RS5C372_RAM_SIZE);
 185         if (ret != 0) {
 186                 printf("%s: failed\n", __FUNCTION__);
 187                 return -1;
 188         }
 189
 190         rs5c372_convert_to_time(tmp, buf);
 191
 192         return 0;
 193 }
 194
 195 /*
 196  * Set the RTC
 197  */
 198 void
 199 rtc_set (struct rtc_time *tmp)
 200 {
 201         unsigned char buf[8], reg15;
 202         int ret;
 203
 204         if (!setup_done)
 205                 rs5c372_enable();
 206
 207         if (!setup_done)
 208                 return;
 209
 210         if(rtc_debug > 2) {
 211                 printf("rtc_set: tm_year = %d\n", tmp->tm_year);
 212                 printf("rtc_set: tm_mon  = %d\n", tmp->tm_mon);
 213                 printf("rtc_set: tm_mday = %d\n", tmp->tm_mday);
 214                 printf("rtc_set: tm_hour = %d\n", tmp->tm_hour);
 215                 printf("rtc_set: tm_min  = %d\n", tmp->tm_min);
 216                 printf("rtc_set: tm_sec  = %d\n", tmp->tm_sec);
 217         }
 218
 219         memset(buf, 0, sizeof(buf));
 220
 221         /* only read register 15 */
 222         ret = i2c_read(CFG_I2C_RTC_ADDR, 0, 0, buf, 1);
 223
 224         if (ret == 0) {
 225                 /* need to save register 15 */
 226                 reg15 = buf[0];
 227                 buf[0] = 0;     /* register address on RS5C372 */
 228                 buf[1] = bin2bcd(tmp->tm_sec);
 229                 buf[2] = bin2bcd(tmp->tm_min);
 230                 /* need to handle 12 hour mode */
 231                 if (TWELVE_HOUR_MODE(reg15)) {
 232                         if (tmp->tm_hour >= 12) { /* PM */
 233                                 /* 12 PM is a special case */
 234                                 if (tmp->tm_hour == 12)
 235                                         buf[3] = bin2bcd(tmp->tm_hour);
 236                                 else
 237                                         buf[3] = bin2bcd(tmp->tm_hour - 12);
 238                                 buf[3] |= 0x20;
 239                         }
 240                 } else {
 241                         buf[3] = bin2bcd(tmp->tm_hour);
 242                 }
 243
 244                 buf[4] = bin2bcd(tmp->tm_wday);
 245                 buf[5] = bin2bcd(tmp->tm_mday);
 246                 buf[6] = bin2bcd(tmp->tm_mon);
 247                 if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
 248                         printf("WARNING: year should be between 1970 and 2069!\n");
 249                 buf[7] = bin2bcd(tmp->tm_year % 100);
 250
 251                 ret = i2c_write(CFG_I2C_RTC_ADDR, 0, 0, buf, 8);
 252                 if (ret != 0)
 253                         printf("rs5c372_set_datetime(), i2c_master_send() returned %d\n",ret);
 254         }
 255
 256         return;
 257 }
 258
 259 /*
 260  * Reset the RTC. We set the date back to 1970-01-01.
 261  */
 262 void
 263 rtc_reset (void)
 264 {
 265         struct rtc_time tmp;
 266
 267         if (!setup_done)
 268                 rs5c372_enable();
 269
 270         if (!setup_done)
 271                 return;
 272
 273         tmp.tm_year = 1970;
 274         tmp.tm_mon = 1;
 275         /* Jan. 1, 1970 was a Thursday */
 276         tmp.tm_wday= 4;
 277         tmp.tm_mday= 1;
 278         tmp.tm_hour = 0;
 279         tmp.tm_min = 0;
 280         tmp.tm_sec = 0;
 281
 282         rtc_set(&tmp);
 283
 284         printf ("RTC:   %4d-%02d-%02d %2d:%02d:%02d UTC\n",
 285                 tmp.tm_year, tmp.tm_mon, tmp.tm_mday,
 286                 tmp.tm_hour, tmp.tm_min, tmp.tm_sec);
 287
 288         return;
 289 }
 290
 291 static unsigned int
 292 bcd2bin (unsigned char n)
 293 {
 294         return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
 295 }
 296
 297 static unsigned char
 298 bin2bcd (unsigned int n)
 299 {
 300         return (((n / 10) << 4) | (n % 10));
 301 }
 302 #endif