1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * (C) Copyright 2001 4 * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com. 5 */ 6 7 /* 8 * Date & Time support for ST Electronics M48T35Ax RTC 9 */ 10 11 /*#define DEBUG */ 12 13 14 #include <common.h> 15 #include <command.h> 16 #include <rtc.h> 17 #include <config.h> 18 19 static uchar rtc_read (uchar reg); 20 static void rtc_write (uchar reg, uchar val); 21 22 /* ------------------------------------------------------------------------- */ 23 24 int rtc_get (struct rtc_time *tmp) 25 { 26 uchar sec, min, hour, cent_day, date, month, year; 27 uchar ccr; /* Clock control register */ 28 29 /* Lock RTC for read using clock control register */ 30 ccr = rtc_read(0); 31 ccr = ccr | 0x40; 32 rtc_write(0, ccr); 33 34 sec = rtc_read (0x1); 35 min = rtc_read (0x2); 36 hour = rtc_read (0x3); 37 cent_day= rtc_read (0x4); 38 date = rtc_read (0x5); 39 month = rtc_read (0x6); 40 year = rtc_read (0x7); 41 42 /* UNLock RTC */ 43 ccr = rtc_read(0); 44 ccr = ccr & 0xBF; 45 rtc_write(0, ccr); 46 47 debug ( "Get RTC year: %02x month: %02x date: %02x cent_day: %02x " 48 "hr: %02x min: %02x sec: %02x\n", 49 year, month, date, cent_day, 50 hour, min, sec ); 51 52 tmp->tm_sec = bcd2bin (sec & 0x7F); 53 tmp->tm_min = bcd2bin (min & 0x7F); 54 tmp->tm_hour = bcd2bin (hour & 0x3F); 55 tmp->tm_mday = bcd2bin (date & 0x3F); 56 tmp->tm_mon = bcd2bin (month & 0x1F); 57 tmp->tm_year = bcd2bin (year) + ((cent_day & 0x10) ? 2000 : 1900); 58 tmp->tm_wday = bcd2bin (cent_day & 0x07); 59 tmp->tm_yday = 0; 60 tmp->tm_isdst= 0; 61 62 debug ( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 63 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 64 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 65 66 return 0; 67 } 68 69 int rtc_set (struct rtc_time *tmp) 70 { 71 uchar ccr; /* Clock control register */ 72 uchar century; 73 74 debug ( "Set 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 /* Lock RTC for write using clock control register */ 79 ccr = rtc_read(0); 80 ccr = ccr | 0x80; 81 rtc_write(0, ccr); 82 83 rtc_write (0x07, bin2bcd(tmp->tm_year % 100)); 84 rtc_write (0x06, bin2bcd(tmp->tm_mon)); 85 rtc_write (0x05, bin2bcd(tmp->tm_mday)); 86 87 century = ((tmp->tm_year >= 2000) ? 0x10 : 0) | 0x20; 88 rtc_write (0x04, bin2bcd(tmp->tm_wday) | century); 89 90 rtc_write (0x03, bin2bcd(tmp->tm_hour)); 91 rtc_write (0x02, bin2bcd(tmp->tm_min )); 92 rtc_write (0x01, bin2bcd(tmp->tm_sec )); 93 94 /* UNLock RTC */ 95 ccr = rtc_read(0); 96 ccr = ccr & 0x7F; 97 rtc_write(0, ccr); 98 99 return 0; 100 } 101 102 void rtc_reset (void) 103 { 104 uchar val; 105 106 /* Clear all clock control registers */ 107 rtc_write (0x0, 0x80); /* No Read Lock or calibration */ 108 109 /* Clear stop bit */ 110 val = rtc_read (0x1); 111 val &= 0x7f; 112 rtc_write(0x1, val); 113 114 /* Enable century / disable frequency test */ 115 val = rtc_read (0x4); 116 val = (val & 0xBF) | 0x20; 117 rtc_write(0x4, val); 118 119 /* Clear write lock */ 120 rtc_write(0x0, 0); 121 } 122 123 /* ------------------------------------------------------------------------- */ 124 125 static uchar rtc_read (uchar reg) 126 { 127 return *(unsigned char *) 128 ((CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE - 8) + reg); 129 } 130 131 static void rtc_write (uchar reg, uchar val) 132 { 133 *(unsigned char *) 134 ((CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE - 8) + reg) = val; 135 } 136