diff options
Diffstat (limited to 'drivers/rtc/max6900.c')
| -rw-r--r-- | drivers/rtc/max6900.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/rtc/max6900.c b/drivers/rtc/max6900.c new file mode 100644 index 0000000..c75a8e0 --- /dev/null +++ b/drivers/rtc/max6900.c @@ -0,0 +1,131 @@ +/* + * (C) Copyright 2004 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + * + * 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 MAXIM MAX6900 RTC + */ + +/* #define DEBUG */ + +#include <common.h> +#include <command.h> +#include <rtc.h> +#include <i2c.h> + +#if defined(CONFIG_RTC_MAX6900) && defined(CONFIG_CMD_DATE) + +#ifndef CFG_I2C_RTC_ADDR +#define CFG_I2C_RTC_ADDR 0x50 +#endif + +/* ------------------------------------------------------------------------- */ + +static uchar rtc_read (uchar reg) +{ + return (i2c_reg_read (CFG_I2C_RTC_ADDR, reg)); +} + +static void rtc_write (uchar reg, uchar val) +{ + i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val); + udelay(2500); +} + +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)); +} + +/* ------------------------------------------------------------------------- */ + +void rtc_get (struct rtc_time *tmp) +{ + uchar sec, min, hour, mday, wday, mon, cent, year; + int retry = 1; + + do { + sec = rtc_read (0x80); + min = rtc_read (0x82); + hour = rtc_read (0x84); + mday = rtc_read (0x86); + mon = rtc_read (0x88); + wday = rtc_read (0x8a); + year = rtc_read (0x8c); + cent = rtc_read (0x92); + /* + * Check for seconds rollover + */ + if ((sec != 59) || (rtc_read(0x80) == sec)){ + retry = 0; + } + } while (retry); + + debug ( "Get RTC year: %02x mon: %02x cent: %02x mday: %02x wday: %02x " + "hr: %02x min: %02x sec: %02x\n", + year, mon, cent, mday, wday, + 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 (mday & 0x3F); + tmp->tm_mon = bcd2bin (mon & 0x1F); + tmp->tm_year = bcd2bin (year) + bcd2bin(cent) * 100; + tmp->tm_wday = bcd2bin (wday & 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) +{ + + 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); + + rtc_write (0x9E, 0x00); + rtc_write (0x80, 0); /* Clear seconds to ensure no rollover */ + rtc_write (0x92, bin2bcd(tmp->tm_year / 100)); + rtc_write (0x8c, bin2bcd(tmp->tm_year % 100)); + rtc_write (0x8a, bin2bcd(tmp->tm_wday)); + rtc_write (0x88, bin2bcd(tmp->tm_mon)); + rtc_write (0x86, bin2bcd(tmp->tm_mday)); + rtc_write (0x84, bin2bcd(tmp->tm_hour)); + rtc_write (0x82, bin2bcd(tmp->tm_min )); + rtc_write (0x80, bin2bcd(tmp->tm_sec )); +} + +void rtc_reset (void) +{ +} + +#endif |