1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * (C) Copyright 2006 4 * Markus Klotzbuecher, mk@denx.de 5 */ 6 7 /* 8 * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim) 9 * Extremly Accurate DS3231 Real Time Clock (RTC). 10 * 11 * copied from ds1337.c 12 */ 13 14 #include <common.h> 15 #include <command.h> 16 #include <rtc.h> 17 #include <i2c.h> 18 19 #if defined(CONFIG_CMD_DATE) 20 21 /* 22 * RTC register addresses 23 */ 24 #define RTC_SEC_REG_ADDR 0x0 25 #define RTC_MIN_REG_ADDR 0x1 26 #define RTC_HR_REG_ADDR 0x2 27 #define RTC_DAY_REG_ADDR 0x3 28 #define RTC_DATE_REG_ADDR 0x4 29 #define RTC_MON_REG_ADDR 0x5 30 #define RTC_YR_REG_ADDR 0x6 31 #define RTC_CTL_REG_ADDR 0x0e 32 #define RTC_STAT_REG_ADDR 0x0f 33 34 35 /* 36 * RTC control register bits 37 */ 38 #define RTC_CTL_BIT_A1IE 0x1 /* Alarm 1 interrupt enable */ 39 #define RTC_CTL_BIT_A2IE 0x2 /* Alarm 2 interrupt enable */ 40 #define RTC_CTL_BIT_INTCN 0x4 /* Interrupt control */ 41 #define RTC_CTL_BIT_RS1 0x8 /* Rate select 1 */ 42 #define RTC_CTL_BIT_RS2 0x10 /* Rate select 2 */ 43 #define RTC_CTL_BIT_DOSC 0x80 /* Disable Oscillator */ 44 45 /* 46 * RTC status register bits 47 */ 48 #define RTC_STAT_BIT_A1F 0x1 /* Alarm 1 flag */ 49 #define RTC_STAT_BIT_A2F 0x2 /* Alarm 2 flag */ 50 #define RTC_STAT_BIT_OSF 0x80 /* Oscillator stop flag */ 51 #define RTC_STAT_BIT_BB32KHZ 0x40 /* Battery backed 32KHz Output */ 52 #define RTC_STAT_BIT_EN32KHZ 0x8 /* Enable 32KHz Output */ 53 54 55 static uchar rtc_read (uchar reg); 56 static void rtc_write (uchar reg, uchar val); 57 58 59 /* 60 * Get the current time from the RTC 61 */ 62 int rtc_get (struct rtc_time *tmp) 63 { 64 int rel = 0; 65 uchar sec, min, hour, mday, wday, mon_cent, year, control, status; 66 67 control = rtc_read (RTC_CTL_REG_ADDR); 68 status = rtc_read (RTC_STAT_REG_ADDR); 69 sec = rtc_read (RTC_SEC_REG_ADDR); 70 min = rtc_read (RTC_MIN_REG_ADDR); 71 hour = rtc_read (RTC_HR_REG_ADDR); 72 wday = rtc_read (RTC_DAY_REG_ADDR); 73 mday = rtc_read (RTC_DATE_REG_ADDR); 74 mon_cent = rtc_read (RTC_MON_REG_ADDR); 75 year = rtc_read (RTC_YR_REG_ADDR); 76 77 debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x " 78 "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n", 79 year, mon_cent, mday, wday, hour, min, sec, control, status); 80 81 if (status & RTC_STAT_BIT_OSF) { 82 printf ("### Warning: RTC oscillator has stopped\n"); 83 /* clear the OSF flag */ 84 rtc_write (RTC_STAT_REG_ADDR, 85 rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF); 86 rel = -1; 87 } 88 89 tmp->tm_sec = bcd2bin (sec & 0x7F); 90 tmp->tm_min = bcd2bin (min & 0x7F); 91 tmp->tm_hour = bcd2bin (hour & 0x3F); 92 tmp->tm_mday = bcd2bin (mday & 0x3F); 93 tmp->tm_mon = bcd2bin (mon_cent & 0x1F); 94 tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900); 95 tmp->tm_wday = bcd2bin ((wday - 1) & 0x07); 96 tmp->tm_yday = 0; 97 tmp->tm_isdst= 0; 98 99 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 100 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 101 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 102 103 return rel; 104 } 105 106 107 /* 108 * Set the RTC 109 */ 110 int rtc_set (struct rtc_time *tmp) 111 { 112 uchar century; 113 114 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 115 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 116 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 117 118 rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100)); 119 120 century = (tmp->tm_year >= 2000) ? 0x80 : 0; 121 rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century); 122 123 rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1)); 124 rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday)); 125 rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour)); 126 rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min)); 127 rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec)); 128 129 return 0; 130 } 131 132 133 /* 134 * Reset the RTC. We also enable the oscillator output on the 135 * SQW/INTB* pin and program it for 32,768 Hz output. Note that 136 * according to the datasheet, turning on the square wave output 137 * increases the current drain on the backup battery from about 138 * 600 nA to 2uA. 139 */ 140 void rtc_reset (void) 141 { 142 rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2); 143 } 144 145 /* 146 * Enable 32KHz output 147 */ 148 void rtc_enable_32khz_output(void) 149 { 150 rtc_write(RTC_STAT_REG_ADDR, 151 RTC_STAT_BIT_BB32KHZ | RTC_STAT_BIT_EN32KHZ); 152 } 153 154 /* 155 * Helper functions 156 */ 157 158 static 159 uchar rtc_read (uchar reg) 160 { 161 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg)); 162 } 163 164 165 static void rtc_write (uchar reg, uchar val) 166 { 167 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val); 168 } 169 170 #endif 171