SD3078_REG_YR
tm->tm_year = bcd2bin(rtc_data[SD3078_REG_YR]) + 100;
rtc_data[SD3078_REG_YR] = bin2bcd(tm->tm_year - 100);
#define NUM_TIME_REGS (SD3078_REG_YR - SD3078_REG_SC + 1)