1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * (C) Copyright 2004 4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 5 */ 6 7 /* 8 * Date & Time support for MAXIM MAX6900 RTC 9 */ 10 11 /* #define DEBUG */ 12 13 #include <common.h> 14 #include <command.h> 15 #include <rtc.h> 16 #include <i2c.h> 17 18 #if defined(CONFIG_CMD_DATE) 19 20 #ifndef CONFIG_SYS_I2C_RTC_ADDR 21 #define CONFIG_SYS_I2C_RTC_ADDR 0x50 22 #endif 23 24 /* ------------------------------------------------------------------------- */ 25 26 static uchar rtc_read (uchar reg) 27 { 28 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg)); 29 } 30 31 static void rtc_write (uchar reg, uchar val) 32 { 33 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val); 34 udelay(2500); 35 } 36 37 /* ------------------------------------------------------------------------- */ 38 39 int rtc_get (struct rtc_time *tmp) 40 { 41 uchar sec, min, hour, mday, wday, mon, cent, year; 42 int retry = 1; 43 44 do { 45 sec = rtc_read (0x80); 46 min = rtc_read (0x82); 47 hour = rtc_read (0x84); 48 mday = rtc_read (0x86); 49 mon = rtc_read (0x88); 50 wday = rtc_read (0x8a); 51 year = rtc_read (0x8c); 52 cent = rtc_read (0x92); 53 /* 54 * Check for seconds rollover 55 */ 56 if ((sec != 59) || (rtc_read(0x80) == sec)){ 57 retry = 0; 58 } 59 } while (retry); 60 61 debug ( "Get RTC year: %02x mon: %02x cent: %02x mday: %02x wday: %02x " 62 "hr: %02x min: %02x sec: %02x\n", 63 year, mon, cent, mday, wday, 64 hour, min, sec ); 65 66 tmp->tm_sec = bcd2bin (sec & 0x7F); 67 tmp->tm_min = bcd2bin (min & 0x7F); 68 tmp->tm_hour = bcd2bin (hour & 0x3F); 69 tmp->tm_mday = bcd2bin (mday & 0x3F); 70 tmp->tm_mon = bcd2bin (mon & 0x1F); 71 tmp->tm_year = bcd2bin (year) + bcd2bin(cent) * 100; 72 tmp->tm_wday = bcd2bin (wday & 0x07); 73 tmp->tm_yday = 0; 74 tmp->tm_isdst= 0; 75 76 debug ( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 77 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 78 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 79 80 return 0; 81 } 82 83 int rtc_set (struct rtc_time *tmp) 84 { 85 86 debug ( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 87 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 88 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 89 90 rtc_write (0x9E, 0x00); 91 rtc_write (0x80, 0); /* Clear seconds to ensure no rollover */ 92 rtc_write (0x92, bin2bcd(tmp->tm_year / 100)); 93 rtc_write (0x8c, bin2bcd(tmp->tm_year % 100)); 94 rtc_write (0x8a, bin2bcd(tmp->tm_wday)); 95 rtc_write (0x88, bin2bcd(tmp->tm_mon)); 96 rtc_write (0x86, bin2bcd(tmp->tm_mday)); 97 rtc_write (0x84, bin2bcd(tmp->tm_hour)); 98 rtc_write (0x82, bin2bcd(tmp->tm_min )); 99 rtc_write (0x80, bin2bcd(tmp->tm_sec )); 100 101 return 0; 102 } 103 104 void rtc_reset (void) 105 { 106 } 107 108 #endif 109