diff options
Diffstat (limited to 'rtc/ds174x.c')
| -rw-r--r-- | rtc/ds174x.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/rtc/ds174x.c b/rtc/ds174x.c new file mode 100644 index 0000000..58b13e9 --- /dev/null +++ b/rtc/ds174x.c @@ -0,0 +1,202 @@ +/* + * (C) Copyright 2001 + * ARIO Data Networks, Inc. dchiu@ariodata.com + * + * Based on MontaVista DS1743 code and U-Boot mc146818 code + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +/* + * Date & Time support for the DS174x RTC + */ + +/*#define DEBUG*/ + +#include <common.h> +#include <command.h> +#include <rtc.h> + +#if defined(CONFIG_RTC_DS174x) && (CONFIG_COMMANDS & CFG_CMD_DATE) + +static uchar rtc_read( unsigned int addr ); +static void rtc_write( unsigned int addr, uchar val); +static uchar bin2bcd (unsigned int n); +static unsigned bcd2bin(uchar c); + +#define RTC_BASE ( CFG_NVRAM_SIZE + CFG_NVRAM_BASE_ADDR ) + +#define RTC_YEAR ( RTC_BASE + 7 ) +#define RTC_MONTH ( RTC_BASE + 6 ) +#define RTC_DAY_OF_MONTH ( RTC_BASE + 5 ) +#define RTC_DAY_OF_WEEK ( RTC_BASE + 4 ) +#define RTC_HOURS ( RTC_BASE + 3 ) +#define RTC_MINUTES ( RTC_BASE + 2 ) +#define RTC_SECONDS ( RTC_BASE + 1 ) +#define RTC_CENTURY ( RTC_BASE + 0 ) + +#define RTC_CONTROLA RTC_CENTURY +#define RTC_CONTROLB RTC_SECONDS +#define RTC_CONTROLC RTC_DAY_OF_WEEK + +#define RTC_CA_WRITE 0x80 +#define RTC_CA_READ 0x40 + +#define RTC_CB_OSC_DISABLE 0x80 + +#define RTC_CC_BATTERY_FLAG 0x80 +#define RTC_CC_FREQ_TEST 0x40 + +/* ------------------------------------------------------------------------- */ + +void rtc_get( struct rtc_time *tmp ) +{ + uchar sec, min, hour; + uchar mday, wday, mon, year; + + int century; + + uchar reg_a; + + reg_a = rtc_read( RTC_CONTROLA ); + /* lock clock registers for read */ + rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ )); + + sec = rtc_read( RTC_SECONDS ); + min = rtc_read( RTC_MINUTES ); + hour = rtc_read( RTC_HOURS ); + mday = rtc_read( RTC_DAY_OF_MONTH ); + wday = rtc_read( RTC_DAY_OF_WEEK ); + mon = rtc_read( RTC_MONTH ); + year = rtc_read( RTC_YEAR ); + century = rtc_read( RTC_CENTURY ); + + /* unlock clock registers after read */ + rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ )); + +#ifdef RTC_DEBUG + printf( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x " + "hr: %02x min: %02x sec: %02x\n", + year, mon_cent, mday, wday, + hour, min, sec ); +#endif + tmp->tm_sec = bcd2bin( sec & 0x7F ); + tmp->tm_min = bcd2bin( min & 0x7F ); + tmp->tm_hour = bcd2bin( hour & 0x3F ); + tmp->tm_mday = bcd2bin( mday & 0x3F ); + tmp->tm_mon = bcd2bin( mon & 0x1F ); + tmp->tm_wday = bcd2bin( wday & 0x07 ); + + /* glue year from century and year in century */ + tmp->tm_year = bcd2bin( year ) + + ( bcd2bin( century & 0x3F ) * 100 ); + + tmp->tm_yday = 0; + tmp->tm_isdst= 0; +#ifdef RTC_DEBUG + printf( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", + tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec ); +#endif +} + +void rtc_set( struct rtc_time *tmp ) +{ + uchar reg_a; +#ifdef RTC_DEBUG + printf( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", + tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec); +#endif + /* lock clock registers for write */ + reg_a = rtc_read( RTC_CONTROLA ); + rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE )); + + rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon )); + + rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday )); + rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday )); + rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour )); + rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min )); + rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec )); + + /* break year up into century and year in century */ + rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 )); + rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 )); + + /* unlock clock registers after read */ + rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_WRITE )); +} + +void rtc_reset (void) +{ + uchar reg_a, reg_b, reg_c; + + reg_a = rtc_read( RTC_CONTROLA ); + reg_b = rtc_read( RTC_CONTROLB ); + + if ( reg_b & RTC_CB_OSC_DISABLE ) + { + printf( "real-time-clock was stopped. Now starting...\n" ); + reg_a |= RTC_CA_WRITE; + reg_b &= ~RTC_CB_OSC_DISABLE; + + rtc_write( RTC_CONTROLA, reg_a ); + rtc_write( RTC_CONTROLB, reg_b ); + } + + /* make sure read/write clock register bits are cleared */ + reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ ); + rtc_write( RTC_CONTROLA, reg_a ); + + reg_c = rtc_read( RTC_CONTROLC ); + if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 ) + printf( "RTC battery low. Clock setting may not be reliable.\n" ); +} + +/* ------------------------------------------------------------------------- */ + +static uchar rtc_read( unsigned int addr ) +{ + uchar val = in8( addr ); +#ifdef RTC_DEBUG + printf( "rtc_read: %x:%x\n", addr, val ); +#endif + return( val ); +} + +static void rtc_write( unsigned int addr, uchar val ) +{ +#ifdef RTC_DEBUG + printf( "rtc_write: %x:%x\n", addr, val ); +#endif + out8( addr, val ); +} + +static unsigned bcd2bin (uchar n) +{ + return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F)); +} + +static unsigned char bin2bcd (unsigned int n) +{ + return (((n / 10) << 4) | (n % 10)); +} + +#endif /* CONFIG_RTC_MC146818 && CFG_CMD_DATE */ |