LXR uboot/drivers/rtc/m41t60.c

   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
  44static 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
  52static 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)
  74static 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
  90static 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
 162int 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
 186int 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
 213void 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