1 /* 2 * (C) Copyright 2006 3 * Markus Klotzbuecher, mk@denx.de 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 /* 9 * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim) 10 * Extremly Accurate DS3231 Real Time Clock (RTC). 11 * 12 * copied from ds1337.c 13 */ 14 15 #include <common.h> 16 #include <command.h> 17 #include <rtc.h> 18 #include <i2c.h> 19 20 #if defined(CONFIG_CMD_DATE) 21 22 /* 23 * RTC register addresses 24 */ 25 #define RTC_SEC_REG_ADDR 0x0 26 #define RTC_MIN_REG_ADDR 0x1 27 #define RTC_HR_REG_ADDR 0x2 28 #define RTC_DAY_REG_ADDR 0x3 29 #define RTC_DATE_REG_ADDR 0x4 30 #define RTC_MON_REG_ADDR 0x5 31 #define RTC_YR_REG_ADDR 0x6 32 #define RTC_CTL_REG_ADDR 0x0e 33 #define RTC_STAT_REG_ADDR 0x0f 34 35 36 /* 37 * RTC control register bits 38 */ 39 #define RTC_CTL_BIT_A1IE 0x1 /* Alarm 1 interrupt enable */ 40 #define RTC_CTL_BIT_A2IE 0x2 /* Alarm 2 interrupt enable */ 41 #define RTC_CTL_BIT_INTCN 0x4 /* Interrupt control */ 42 #define RTC_CTL_BIT_RS1 0x8 /* Rate select 1 */ 43 #define RTC_CTL_BIT_RS2 0x10 /* Rate select 2 */ 44 #define RTC_CTL_BIT_DOSC 0x80 /* Disable Oscillator */ 45 46 /* 47 * RTC status register bits 48 */ 49 #define RTC_STAT_BIT_A1F 0x1 /* Alarm 1 flag */ 50 #define RTC_STAT_BIT_A2F 0x2 /* Alarm 2 flag */ 51 #define RTC_STAT_BIT_OSF 0x80 /* Oscillator stop flag */ 52 53 54 static uchar rtc_read (uchar reg); 55 static void rtc_write (uchar reg, uchar val); 56 57 58 /* 59 * Get the current time from the RTC 60 */ 61 int rtc_get (struct rtc_time *tmp) 62 { 63 int rel = 0; 64 uchar sec, min, hour, mday, wday, mon_cent, year, control, status; 65 66 control = rtc_read (RTC_CTL_REG_ADDR); 67 status = rtc_read (RTC_STAT_REG_ADDR); 68 sec = rtc_read (RTC_SEC_REG_ADDR); 69 min = rtc_read (RTC_MIN_REG_ADDR); 70 hour = rtc_read (RTC_HR_REG_ADDR); 71 wday = rtc_read (RTC_DAY_REG_ADDR); 72 mday = rtc_read (RTC_DATE_REG_ADDR); 73 mon_cent = rtc_read (RTC_MON_REG_ADDR); 74 year = rtc_read (RTC_YR_REG_ADDR); 75 76 debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x " 77 "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n", 78 year, mon_cent, mday, wday, hour, min, sec, control, status); 79 80 if (status & RTC_STAT_BIT_OSF) { 81 printf ("### Warning: RTC oscillator has stopped\n"); 82 /* clear the OSF flag */ 83 rtc_write (RTC_STAT_REG_ADDR, 84 rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF); 85 rel = -1; 86 } 87 88 tmp->tm_sec = bcd2bin (sec & 0x7F); 89 tmp->tm_min = bcd2bin (min & 0x7F); 90 tmp->tm_hour = bcd2bin (hour & 0x3F); 91 tmp->tm_mday = bcd2bin (mday & 0x3F); 92 tmp->tm_mon = bcd2bin (mon_cent & 0x1F); 93 tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900); 94 tmp->tm_wday = bcd2bin ((wday - 1) & 0x07); 95 tmp->tm_yday = 0; 96 tmp->tm_isdst= 0; 97 98 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 99 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 100 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 101 102 return rel; 103 } 104 105 106 /* 107 * Set the RTC 108 */ 109 int rtc_set (struct rtc_time *tmp) 110 { 111 uchar century; 112 113 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 114 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 115 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 116 117 rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100)); 118 119 century = (tmp->tm_year >= 2000) ? 0x80 : 0; 120 rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century); 121 122 rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1)); 123 rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday)); 124 rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour)); 125 rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min)); 126 rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec)); 127 128 return 0; 129 } 130 131 132 /* 133 * Reset the RTC. We also enable the oscillator output on the 134 * SQW/INTB* pin and program it for 32,768 Hz output. Note that 135 * according to the datasheet, turning on the square wave output 136 * increases the current drain on the backup battery from about 137 * 600 nA to 2uA. 138 */ 139 void rtc_reset (void) 140 { 141 rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2); 142 } 143 144 145 /* 146 * Helper functions 147 */ 148 149 static 150 uchar rtc_read (uchar reg) 151 { 152 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg)); 153 } 154 155 156 static void rtc_write (uchar reg, uchar val) 157 { 158 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val); 159 } 160 161 #endif 162