]>
git.ipfire.org Git - people/ms/u-boot.git/blob - rtc/ds1307.c
2 * (C) Copyright 2001, 2002, 2003
3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4 * Keith Outwater, keith_outwater@mvis.com`
5 * Steven Scholz, steven.scholz@imc-berlin.de
7 * See file CREDITS for list of people who contributed to this
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of
13 * the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
28 * DS1307 Real Time Clock (RTC).
38 #if defined(CONFIG_RTC_DS1307) && (CONFIG_COMMANDS & CFG_CMD_DATE)
40 /*---------------------------------------------------------------------*/
44 #define DEBUGR(fmt,args...) printf(fmt ,##args)
46 #define DEBUGR(fmt,args...)
48 /*---------------------------------------------------------------------*/
50 #ifndef CFG_I2C_RTC_ADDR
51 # define CFG_I2C_RTC_ADDR 0x68
54 #if CFG_I2C_SPEED > 100000
55 # error The DS1307 is specified only up to 100kHz!
59 * RTC register addresses
61 #define RTC_SEC_REG_ADDR 0x00
62 #define RTC_MIN_REG_ADDR 0x01
63 #define RTC_HR_REG_ADDR 0x02
64 #define RTC_DAY_REG_ADDR 0x03
65 #define RTC_DATE_REG_ADDR 0x04
66 #define RTC_MON_REG_ADDR 0x05
67 #define RTC_YR_REG_ADDR 0x06
68 #define RTC_CTL_REG_ADDR 0x07
70 #define RTC_SEC_BIT_CH 0x80 /* Clock Halt (in Register 0) */
72 #define RTC_CTL_BIT_RS0 0x01 /* Rate select 0 */
73 #define RTC_CTL_BIT_RS1 0x02 /* Rate select 1 */
74 #define RTC_CTL_BIT_SQWE 0x10 /* Square Wave Enable */
75 #define RTC_CTL_BIT_OUT 0x80 /* Output Control */
77 static uchar
rtc_read (uchar reg
);
78 static void rtc_write (uchar reg
, uchar val
);
79 static uchar
bin2bcd (unsigned int n
);
80 static unsigned bcd2bin (uchar c
);
83 * Get the current time from the RTC
85 void rtc_get (struct rtc_time
*tmp
)
87 uchar sec
, min
, hour
, mday
, wday
, mon
, year
;
89 sec
= rtc_read (RTC_SEC_REG_ADDR
);
90 min
= rtc_read (RTC_MIN_REG_ADDR
);
91 hour
= rtc_read (RTC_HR_REG_ADDR
);
92 wday
= rtc_read (RTC_DAY_REG_ADDR
);
93 mday
= rtc_read (RTC_DATE_REG_ADDR
);
94 mon
= rtc_read (RTC_MON_REG_ADDR
);
95 year
= rtc_read (RTC_YR_REG_ADDR
);
97 DEBUGR ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
98 "hr: %02x min: %02x sec: %02x\n",
99 year
, mon
, mday
, wday
, hour
, min
, sec
);
101 if (sec
& RTC_SEC_BIT_CH
) {
102 printf ("### Warning: RTC oscillator has stopped\n");
103 /* clear the CH flag */
104 rtc_write (RTC_SEC_REG_ADDR
,
105 rtc_read (RTC_SEC_REG_ADDR
) & ~RTC_SEC_BIT_CH
);
108 tmp
->tm_sec
= bcd2bin (sec
& 0x7F);
109 tmp
->tm_min
= bcd2bin (min
& 0x7F);
110 tmp
->tm_hour
= bcd2bin (hour
& 0x3F);
111 tmp
->tm_mday
= bcd2bin (mday
& 0x3F);
112 tmp
->tm_mon
= bcd2bin (mon
& 0x1F);
113 tmp
->tm_year
= bcd2bin (year
) + ( bcd2bin (year
) >= 70 ? 1900 : 2000);
114 tmp
->tm_wday
= bcd2bin ((wday
- 1) & 0x07);
118 DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
119 tmp
->tm_year
, tmp
->tm_mon
, tmp
->tm_mday
, tmp
->tm_wday
,
120 tmp
->tm_hour
, tmp
->tm_min
, tmp
->tm_sec
);
127 void rtc_set (struct rtc_time
*tmp
)
129 DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
130 tmp
->tm_year
, tmp
->tm_mon
, tmp
->tm_mday
, tmp
->tm_wday
,
131 tmp
->tm_hour
, tmp
->tm_min
, tmp
->tm_sec
);
133 if (tmp
->tm_year
< 1970 || tmp
->tm_year
> 2069)
134 printf("WARNING: year should be between 1970 and 2069!\n");
136 rtc_write (RTC_YR_REG_ADDR
, bin2bcd (tmp
->tm_year
% 100));
137 rtc_write (RTC_MON_REG_ADDR
, bin2bcd (tmp
->tm_mon
));
138 rtc_write (RTC_DAY_REG_ADDR
, bin2bcd (tmp
->tm_wday
+ 1));
139 rtc_write (RTC_DATE_REG_ADDR
, bin2bcd (tmp
->tm_mday
));
140 rtc_write (RTC_HR_REG_ADDR
, bin2bcd (tmp
->tm_hour
));
141 rtc_write (RTC_MIN_REG_ADDR
, bin2bcd (tmp
->tm_min
));
142 rtc_write (RTC_SEC_REG_ADDR
, bin2bcd (tmp
->tm_sec
));
147 * Reset the RTC. We setting the date back to 1970-01-01.
148 * We also enable the oscillator output on the SQW/OUT pin and program
149 * it for 32,768 Hz output. Note that according to the datasheet, turning
150 * on the square wave output increases the current drain on the backup
151 * battery to something between 480nA and 800nA.
153 void rtc_reset (void)
157 rtc_write (RTC_SEC_REG_ADDR
, 0x00); /* clearing Clock Halt */
158 rtc_write (RTC_CTL_REG_ADDR
, RTC_CTL_BIT_SQWE
| RTC_CTL_BIT_RS1
| RTC_CTL_BIT_RS0
);
169 printf ( "RTC: %4d-%02d-%02d %2d:%02d:%02d UTC\n",
170 tmp
.tm_year
, tmp
.tm_mon
, tmp
.tm_mday
,
171 tmp
.tm_hour
, tmp
.tm_min
, tmp
.tm_sec
);
182 uchar
rtc_read (uchar reg
)
184 return (i2c_reg_read (CFG_I2C_RTC_ADDR
, reg
));
188 static void rtc_write (uchar reg
, uchar val
)
190 i2c_reg_write (CFG_I2C_RTC_ADDR
, reg
, val
);
193 static unsigned bcd2bin (uchar n
)
195 return ((((n
>> 4) & 0x0F) * 10) + (n
& 0x0F));
198 static unsigned char bin2bcd (unsigned int n
)
200 return (((n
/ 10) << 4) | (n
% 10));
203 #endif /* CONFIG_RTC_DS1307 && (CFG_COMMANDS & CFG_CMD_DATE) */