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 #ifndef CONFIG_SYS_I2C_RTC_ADDR 19 #define CONFIG_SYS_I2C_RTC_ADDR 0x50 20 #endif 21 22 /* ------------------------------------------------------------------------- */ 23 24 static uchar rtc_read (uchar reg) 25 { 26 return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg)); 27 } 28 29 static void rtc_write (uchar reg, uchar val) 30 { 31 i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val); 32 udelay(2500); 33 } 34 35 /* ------------------------------------------------------------------------- */ 36 37 int rtc_get (struct rtc_time *tmp) 38 { 39 uchar sec, min, hour, mday, wday, mon, cent, year; 40 int retry = 1; 41 42 do { 43 sec = rtc_read (0x80); 44 min = rtc_read (0x82); 45 hour = rtc_read (0x84); 46 mday = rtc_read (0x86); 47 mon = rtc_read (0x88); 48 wday = rtc_read (0x8a); 49 year = rtc_read (0x8c); 50 cent = rtc_read (0x92); 51 /* 52 * Check for seconds rollover 53 */ 54 if ((sec != 59) || (rtc_read(0x80) == sec)){ 55 retry = 0; 56 } 57 } while (retry); 58 59 debug ( "Get RTC year: %02x mon: %02x cent: %02x mday: %02x wday: %02x " 60 "hr: %02x min: %02x sec: %02x\n", 61 year, mon, cent, mday, wday, 62 hour, min, sec ); 63 64 tmp->tm_sec = bcd2bin (sec & 0x7F); 65 tmp->tm_min = bcd2bin (min & 0x7F); 66 tmp->tm_hour = bcd2bin (hour & 0x3F); 67 tmp->tm_mday = bcd2bin (mday & 0x3F); 68 tmp->tm_mon = bcd2bin (mon & 0x1F); 69 tmp->tm_year = bcd2bin (year) + bcd2bin(cent) * 100; 70 tmp->tm_wday = bcd2bin (wday & 0x07); 71 tmp->tm_yday = 0; 72 tmp->tm_isdst= 0; 73 74 debug ( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 75 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 76 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 77 78 return 0; 79 } 80 81 int rtc_set (struct rtc_time *tmp) 82 { 83 84 debug ( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 85 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 86 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 87 88 rtc_write (0x9E, 0x00); 89 rtc_write (0x80, 0); /* Clear seconds to ensure no rollover */ 90 rtc_write (0x92, bin2bcd(tmp->tm_year / 100)); 91 rtc_write (0x8c, bin2bcd(tmp->tm_year % 100)); 92 rtc_write (0x8a, bin2bcd(tmp->tm_wday)); 93 rtc_write (0x88, bin2bcd(tmp->tm_mon)); 94 rtc_write (0x86, bin2bcd(tmp->tm_mday)); 95 rtc_write (0x84, bin2bcd(tmp->tm_hour)); 96 rtc_write (0x82, bin2bcd(tmp->tm_min )); 97 rtc_write (0x80, bin2bcd(tmp->tm_sec )); 98 99 return 0; 100 } 101 102 void rtc_reset (void) 103 { 104 } 105