summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/max6900.c
blob: 758d7b79d94323fa135794ab8a5682c6cc6280fd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
/*
 * (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_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));
}

/* ------------------------------------------------------------------------- */

int 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);

	return 0;
}

int 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 ));

	return 0;
}

void rtc_reset (void)
{
}

#endif
OpenPOWER on IntegriCloud