1 /* 2 * (C) Copyright 2004 3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 /* 9 * Date & Time support for MAXIM MAX6900 RTC 10 */ 11 12 /* #define DEBUG */ 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 #ifndef CONFIG_SYS_I2C_RTC_ADDR 22 #define CONFIG_SYS_I2C_RTC_ADDR 0x50 23 #endif 24 25 /* ------------------------------------------------------------------------- */ 26 27 static uchar rtc_read (uchar reg) 28 { 29 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg)); 30 } 31 32 static void rtc_write (uchar reg, uchar val) 33 { 34 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val); 35 udelay(2500); 36 } 37 38 /* ------------------------------------------------------------------------- */ 39 40 int rtc_get (struct rtc_time *tmp) 41 { 42 uchar sec, min, hour, mday, wday, mon, cent, year; 43 int retry = 1; 44 45 do { 46 sec = rtc_read (0x80); 47 min = rtc_read (0x82); 48 hour = rtc_read (0x84); 49 mday = rtc_read (0x86); 50 mon = rtc_read (0x88); 51 wday = rtc_read (0x8a); 52 year = rtc_read (0x8c); 53 cent = rtc_read (0x92); 54 /* 55 * Check for seconds rollover 56 */ 57 if ((sec != 59) || (rtc_read(0x80) == sec)){ 58 retry = 0; 59 } 60 } while (retry); 61 62 debug ( "Get RTC year: %02x mon: %02x cent: %02x mday: %02x wday: %02x " 63 "hr: %02x min: %02x sec: %02x\n", 64 year, mon, cent, mday, wday, 65 hour, min, sec ); 66 67 tmp->tm_sec = bcd2bin (sec & 0x7F); 68 tmp->tm_min = bcd2bin (min & 0x7F); 69 tmp->tm_hour = bcd2bin (hour & 0x3F); 70 tmp->tm_mday = bcd2bin (mday & 0x3F); 71 tmp->tm_mon = bcd2bin (mon & 0x1F); 72 tmp->tm_year = bcd2bin (year) + bcd2bin(cent) * 100; 73 tmp->tm_wday = bcd2bin (wday & 0x07); 74 tmp->tm_yday = 0; 75 tmp->tm_isdst= 0; 76 77 debug ( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 78 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 79 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 80 81 return 0; 82 } 83 84 int rtc_set (struct rtc_time *tmp) 85 { 86 87 debug ( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 88 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 89 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 90 91 rtc_write (0x9E, 0x00); 92 rtc_write (0x80, 0); /* Clear seconds to ensure no rollover */ 93 rtc_write (0x92, bin2bcd(tmp->tm_year / 100)); 94 rtc_write (0x8c, bin2bcd(tmp->tm_year % 100)); 95 rtc_write (0x8a, bin2bcd(tmp->tm_wday)); 96 rtc_write (0x88, bin2bcd(tmp->tm_mon)); 97 rtc_write (0x86, bin2bcd(tmp->tm_mday)); 98 rtc_write (0x84, bin2bcd(tmp->tm_hour)); 99 rtc_write (0x82, bin2bcd(tmp->tm_min )); 100 rtc_write (0x80, bin2bcd(tmp->tm_sec )); 101 102 return 0; 103 } 104 105 void rtc_reset (void) 106 { 107 } 108 109 #endif 110