diff options
Diffstat (limited to 'drivers/rtc/m48t35ax.c')
| -rw-r--r-- | drivers/rtc/m48t35ax.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/drivers/rtc/m48t35ax.c b/drivers/rtc/m48t35ax.c new file mode 100644 index 0000000..0a0ffa8 --- /dev/null +++ b/drivers/rtc/m48t35ax.c @@ -0,0 +1,166 @@ +/* + * (C) Copyright 2001 + * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com. + * + * 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 ST Electronics M48T35Ax RTC + */ + +/*#define DEBUG */ + + +#include <common.h> +#include <command.h> +#include <rtc.h> +#include <config.h> + +#if defined(CONFIG_RTC_M48T35A) && defined(CONFIG_CMD_DATE) + +static uchar rtc_read (uchar reg); +static void rtc_write (uchar reg, uchar val); +static uchar bin2bcd (unsigned int n); +static unsigned bcd2bin(uchar c); + +/* ------------------------------------------------------------------------- */ + +void rtc_get (struct rtc_time *tmp) +{ + uchar sec, min, hour, cent_day, date, month, year; + uchar ccr; /* Clock control register */ + + /* Lock RTC for read using clock control register */ + ccr = rtc_read(0); + ccr = ccr | 0x40; + rtc_write(0, ccr); + + sec = rtc_read (0x1); + min = rtc_read (0x2); + hour = rtc_read (0x3); + cent_day= rtc_read (0x4); + date = rtc_read (0x5); + month = rtc_read (0x6); + year = rtc_read (0x7); + + /* UNLock RTC */ + ccr = rtc_read(0); + ccr = ccr & 0xBF; + rtc_write(0, ccr); + + debug ( "Get RTC year: %02x month: %02x date: %02x cent_day: %02x " + "hr: %02x min: %02x sec: %02x\n", + year, month, date, cent_day, + hour, min, sec ); + + tmp->tm_sec = bcd2bin (sec & 0x7F); + tmp->tm_min = bcd2bin (min & 0x7F); + tmp->tm_hour = bcd2bin (hour & 0x3F); + tmp->tm_mday = bcd2bin (date & 0x3F); + tmp->tm_mon = bcd2bin (month & 0x1F); + tmp->tm_year = bcd2bin (year) + ((cent_day & 0x10) ? 2000 : 1900); + tmp->tm_wday = bcd2bin (cent_day & 0x07); + tmp->tm_yday = 0; + tmp->tm_isdst= 0; + + debug ( "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); +} + +void rtc_set (struct rtc_time *tmp) +{ + uchar ccr; /* Clock control register */ + uchar century; + + debug ( "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); + + /* Lock RTC for write using clock control register */ + ccr = rtc_read(0); + ccr = ccr | 0x80; + rtc_write(0, ccr); + + rtc_write (0x07, bin2bcd(tmp->tm_year % 100)); + rtc_write (0x06, bin2bcd(tmp->tm_mon)); + rtc_write (0x05, bin2bcd(tmp->tm_mday)); + + century = ((tmp->tm_year >= 2000) ? 0x10 : 0) | 0x20; + rtc_write (0x04, bin2bcd(tmp->tm_wday) | century); + + rtc_write (0x03, bin2bcd(tmp->tm_hour)); + rtc_write (0x02, bin2bcd(tmp->tm_min )); + rtc_write (0x01, bin2bcd(tmp->tm_sec )); + + /* UNLock RTC */ + ccr = rtc_read(0); + ccr = ccr & 0x7F; + rtc_write(0, ccr); +} + +void rtc_reset (void) +{ + uchar val; + + /* Clear all clock control registers */ + rtc_write (0x0, 0x80); /* No Read Lock or calibration */ + + /* Clear stop bit */ + val = rtc_read (0x1); + val &= 0x7f; + rtc_write(0x1, val); + + /* Enable century / disable frequency test */ + val = rtc_read (0x4); + val = (val & 0xBF) | 0x20; + rtc_write(0x4, val); + + /* Clear write lock */ + rtc_write(0x0, 0); +} + +/* ------------------------------------------------------------------------- */ + +static uchar rtc_read (uchar reg) +{ + uchar val; + val = *(unsigned char *) + ((CFG_NVRAM_BASE_ADDR + CFG_NVRAM_SIZE - 8) + reg); + return val; +} + +static void rtc_write (uchar reg, uchar val) +{ + *(unsigned char *) + ((CFG_NVRAM_BASE_ADDR + CFG_NVRAM_SIZE - 8) + reg) = 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 |