diff options
Diffstat (limited to 'drivers/rtc/ds1307.c')
| -rw-r--r-- | drivers/rtc/ds1307.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/rtc/ds1307.c b/drivers/rtc/ds1307.c new file mode 100644 index 0000000000..c882d7989a --- /dev/null +++ b/drivers/rtc/ds1307.c @@ -0,0 +1,204 @@ +/* + * (C) Copyright 2001, 2002, 2003 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + * Keith Outwater, keith_outwater@mvis.com` + * Steven Scholz, steven.scholz@imc-berlin.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 (no alarms) for Dallas Semiconductor (now Maxim) + * DS1307 and DS1338 Real Time Clock (RTC). + * + * based on ds1337.c + */ + +#include <common.h> +#include <command.h> +#include <rtc.h> +#include <i2c.h> + +#if (defined(CONFIG_RTC_DS1307) || defined(CONFIG_RTC_DS1338) ) && \ + defined(CONFIG_CMD_DATE) + +/*---------------------------------------------------------------------*/ +#undef DEBUG_RTC + +#ifdef DEBUG_RTC +#define DEBUGR(fmt,args...) printf(fmt ,##args) +#else +#define DEBUGR(fmt,args...) +#endif +/*---------------------------------------------------------------------*/ + +#ifndef CFG_I2C_RTC_ADDR +# define CFG_I2C_RTC_ADDR 0x68 +#endif + +#if defined(CONFIG_RTC_DS1307) && (CFG_I2C_SPEED > 100000) +# error The DS1307 is specified only up to 100kHz! +#endif + +/* + * RTC register addresses + */ +#define RTC_SEC_REG_ADDR 0x00 +#define RTC_MIN_REG_ADDR 0x01 +#define RTC_HR_REG_ADDR 0x02 +#define RTC_DAY_REG_ADDR 0x03 +#define RTC_DATE_REG_ADDR 0x04 +#define RTC_MON_REG_ADDR 0x05 +#define RTC_YR_REG_ADDR 0x06 +#define RTC_CTL_REG_ADDR 0x07 + +#define RTC_SEC_BIT_CH 0x80 /* Clock Halt (in Register 0) */ + +#define RTC_CTL_BIT_RS0 0x01 /* Rate select 0 */ +#define RTC_CTL_BIT_RS1 0x02 /* Rate select 1 */ +#define RTC_CTL_BIT_SQWE 0x10 /* Square Wave Enable */ +#define RTC_CTL_BIT_OUT 0x80 /* Output Control */ + +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); + +/* + * Get the current time from the RTC + */ +void rtc_get (struct rtc_time *tmp) +{ + uchar sec, min, hour, mday, wday, mon, year; + + sec = rtc_read (RTC_SEC_REG_ADDR); + min = rtc_read (RTC_MIN_REG_ADDR); + hour = rtc_read (RTC_HR_REG_ADDR); + wday = rtc_read (RTC_DAY_REG_ADDR); + mday = rtc_read (RTC_DATE_REG_ADDR); + mon = rtc_read (RTC_MON_REG_ADDR); + year = rtc_read (RTC_YR_REG_ADDR); + + DEBUGR ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x " + "hr: %02x min: %02x sec: %02x\n", + year, mon, mday, wday, hour, min, sec); + + if (sec & RTC_SEC_BIT_CH) { + printf ("### Warning: RTC oscillator has stopped\n"); + /* clear the CH flag */ + rtc_write (RTC_SEC_REG_ADDR, + rtc_read (RTC_SEC_REG_ADDR) & ~RTC_SEC_BIT_CH); + } + + 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 (year) >= 70 ? 1900 : 2000); + tmp->tm_wday = bcd2bin ((wday - 1) & 0x07); + tmp->tm_yday = 0; + tmp->tm_isdst= 0; + + DEBUGR ("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); +} + + +/* + * Set the RTC + */ +void rtc_set (struct rtc_time *tmp) +{ + DEBUGR ("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); + + if (tmp->tm_year < 1970 || tmp->tm_year > 2069) + printf("WARNING: year should be between 1970 and 2069!\n"); + + rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100)); + rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon)); + rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1)); + rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday)); + rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour)); + rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min)); + rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec)); +} + + +/* + * Reset the RTC. We setting the date back to 1970-01-01. + * We also enable the oscillator output on the SQW/OUT pin and program + * it for 32,768 Hz output. Note that according to the datasheet, turning + * on the square wave output increases the current drain on the backup + * battery to something between 480nA and 800nA. + */ +void rtc_reset (void) +{ + struct rtc_time tmp; + + rtc_write (RTC_SEC_REG_ADDR, 0x00); /* clearing Clock Halt */ + rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS0); + + tmp.tm_year = 1970; + tmp.tm_mon = 1; + tmp.tm_mday= 1; + tmp.tm_hour = 0; + tmp.tm_min = 0; + tmp.tm_sec = 0; + + rtc_set(&tmp); + + printf ( "RTC: %4d-%02d-%02d %2d:%02d:%02d UTC\n", + tmp.tm_year, tmp.tm_mon, tmp.tm_mday, + tmp.tm_hour, tmp.tm_min, tmp.tm_sec); + + return; +} + + +/* + * Helper functions + */ + +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); +} + +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 |