/* * (C) Copyright 2006 * Markus Klotzbuecher, mk@denx.de * * SPDX-License-Identifier: GPL-2.0+ */ /* * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim) * Extremly Accurate DS3231 Real Time Clock (RTC). * * copied from ds1337.c */ #include <common.h> #include <command.h> #include <rtc.h> #include <i2c.h> #if defined(CONFIG_CMD_DATE) /* * RTC register addresses */ #define RTC_SEC_REG_ADDR 0x0 #define RTC_MIN_REG_ADDR 0x1 #define RTC_HR_REG_ADDR 0x2 #define RTC_DAY_REG_ADDR 0x3 #define RTC_DATE_REG_ADDR 0x4 #define RTC_MON_REG_ADDR 0x5 #define RTC_YR_REG_ADDR 0x6 #define RTC_CTL_REG_ADDR 0x0e #define RTC_STAT_REG_ADDR 0x0f /* * RTC control register bits */ #define RTC_CTL_BIT_A1IE 0x1 /* Alarm 1 interrupt enable */ #define RTC_CTL_BIT_A2IE 0x2 /* Alarm 2 interrupt enable */ #define RTC_CTL_BIT_INTCN 0x4 /* Interrupt control */ #define RTC_CTL_BIT_RS1 0x8 /* Rate select 1 */ #define RTC_CTL_BIT_RS2 0x10 /* Rate select 2 */ #define RTC_CTL_BIT_DOSC 0x80 /* Disable Oscillator */ /* * RTC status register bits */ #define RTC_STAT_BIT_A1F 0x1 /* Alarm 1 flag */ #define RTC_STAT_BIT_A2F 0x2 /* Alarm 2 flag */ #define RTC_STAT_BIT_OSF 0x80 /* Oscillator stop flag */ static uchar rtc_read (uchar reg); static void rtc_write (uchar reg, uchar val); /* * Get the current time from the RTC */ int rtc_get (struct rtc_time *tmp) { int rel = 0; uchar sec, min, hour, mday, wday, mon_cent, year, control, status; control = rtc_read (RTC_CTL_REG_ADDR); status = rtc_read (RTC_STAT_REG_ADDR); sec = rtc_read (RTC_SEC_REG_ADDR); min = rtc_read (RTC_MIN_REG_ADDR); hour = rtc_read (RTC_HR_REG_ADDR); wday = rtc_read (RTC_DAY_REG_ADDR); mday = rtc_read (RTC_DATE_REG_ADDR); mon_cent = rtc_read (RTC_MON_REG_ADDR); year = rtc_read (RTC_YR_REG_ADDR); debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x " "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n", year, mon_cent, mday, wday, hour, min, sec, control, status); if (status & RTC_STAT_BIT_OSF) { printf ("### Warning: RTC oscillator has stopped\n"); /* clear the OSF flag */ rtc_write (RTC_STAT_REG_ADDR, rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF); rel = -1; } tmp->tm_sec = bcd2bin (sec & 0x7F); tmp->tm_min = bcd2bin (min & 0x7F); tmp->tm_hour = bcd2bin (hour & 0x3F); tmp->tm_mday = bcd2bin (mday & 0x3F); tmp->tm_mon = bcd2bin (mon_cent & 0x1F); tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900); tmp->tm_wday = bcd2bin ((wday - 1) & 0x07); tmp->tm_yday = 0; tmp->tm_isdst= 0; debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, tmp->tm_hour, tmp->tm_min, tmp->tm_sec); return rel; } /* * Set the RTC */ int rtc_set (struct rtc_time *tmp) { uchar century; debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, tmp->tm_hour, tmp->tm_min, tmp->tm_sec); rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100)); century = (tmp->tm_year >= 2000) ? 0x80 : 0; rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century); rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1)); rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday)); rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour)); rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min)); rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec)); return 0; } /* * Reset the RTC. We also enable the oscillator output on the * SQW/INTB* pin and program it for 32,768 Hz output. Note that * according to the datasheet, turning on the square wave output * increases the current drain on the backup battery from about * 600 nA to 2uA. */ void rtc_reset (void) { rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2); } /* * Helper functions */ static uchar rtc_read (uchar reg) { return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg)); } static void rtc_write (uchar reg, uchar val) { i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val); } #endif