summaryrefslogtreecommitdiff
path: root/drivers/rtc/ds174x.c
blob: 5a55dc8b7adb112657850d949b8a58a377efb656 (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
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
/*
 * (C) Copyright 2001
 * ARIO Data Networks, Inc. dchiu@ariodata.com
 *
 * Based on MontaVista DS1743 code and U-Boot mc146818 code
 *
 * 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 the DS174x RTC
 */

/*#define	DEBUG*/

#include <common.h>
#include <command.h>
#include <rtc.h>

#if defined(CONFIG_CMD_DATE)

static uchar rtc_read( unsigned int addr );
static void  rtc_write( unsigned int addr, uchar val);

#define RTC_BASE		( CONFIG_SYS_NVRAM_SIZE + CONFIG_SYS_NVRAM_BASE_ADDR )

#define RTC_YEAR		( RTC_BASE + 7 )
#define RTC_MONTH		( RTC_BASE + 6 )
#define RTC_DAY_OF_MONTH	( RTC_BASE + 5 )
#define RTC_DAY_OF_WEEK		( RTC_BASE + 4 )
#define RTC_HOURS		( RTC_BASE + 3 )
#define RTC_MINUTES		( RTC_BASE + 2 )
#define RTC_SECONDS		( RTC_BASE + 1 )
#define RTC_CENTURY		( RTC_BASE + 0 )

#define RTC_CONTROLA		RTC_CENTURY
#define RTC_CONTROLB		RTC_SECONDS
#define RTC_CONTROLC		RTC_DAY_OF_WEEK

#define RTC_CA_WRITE		0x80
#define RTC_CA_READ		0x40

#define RTC_CB_OSC_DISABLE	0x80

#define RTC_CC_BATTERY_FLAG	0x80
#define RTC_CC_FREQ_TEST	0x40

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

int rtc_get( struct rtc_time *tmp )
{
	uchar sec, min, hour;
	uchar mday, wday, mon, year;

	int century;

	uchar reg_a;

	reg_a = rtc_read( RTC_CONTROLA );
	/* lock clock registers for read */
	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));

	sec     = rtc_read( RTC_SECONDS );
	min     = rtc_read( RTC_MINUTES );
	hour    = rtc_read( RTC_HOURS );
	mday    = rtc_read( RTC_DAY_OF_MONTH );
	wday    = rtc_read( RTC_DAY_OF_WEEK );
	mon     = rtc_read( RTC_MONTH );
	year    = rtc_read( RTC_YEAR );
	century = rtc_read( RTC_CENTURY );

	/* unlock clock registers after read */
	rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));

#ifdef RTC_DEBUG
	printf( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
		"hr: %02x min: %02x sec: %02x\n",
		year, mon_cent, mday, wday,
		hour, min, sec );
#endif
	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_wday = bcd2bin( wday & 0x07 );

	/* glue year from century and year in century */
	tmp->tm_year = bcd2bin( year ) +
		( bcd2bin( century & 0x3F ) * 100 );

	tmp->tm_yday = 0;
	tmp->tm_isdst= 0;
#ifdef RTC_DEBUG
	printf( "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 );
#endif
	return 0;
}

int rtc_set( struct rtc_time *tmp )
{
	uchar reg_a;
#ifdef RTC_DEBUG
	printf( "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);
#endif
	/* lock clock registers for write */
	reg_a = rtc_read( RTC_CONTROLA );
	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));

	rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));

	rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
	rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
	rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
	rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
	rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));

	/* break year up into century and year in century */
	rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
	rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 ));

	/* unlock clock registers after read */
	rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));

	return 0;
}

void rtc_reset (void)
{
	uchar reg_a, reg_b, reg_c;

	reg_a = rtc_read( RTC_CONTROLA );
	reg_b = rtc_read( RTC_CONTROLB );

	if ( reg_b & RTC_CB_OSC_DISABLE )
	{
		printf( "real-time-clock was stopped. Now starting...\n" );
		reg_a |= RTC_CA_WRITE;
		reg_b &= ~RTC_CB_OSC_DISABLE;

		rtc_write( RTC_CONTROLA, reg_a );
		rtc_write( RTC_CONTROLB, reg_b );
	}

	/* make sure read/write clock register bits are cleared */
	reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
	rtc_write( RTC_CONTROLA, reg_a );

	reg_c = rtc_read( RTC_CONTROLC );
	if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 )
		printf( "RTC battery low. Clock setting may not be reliable.\n" );
}

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

static uchar rtc_read( unsigned int addr )
{
	uchar val = in8( addr );
#ifdef RTC_DEBUG
	printf( "rtc_read: %x:%x\n", addr, val );
#endif
	return( val );
}

static void rtc_write( unsigned int addr, uchar val )
{
#ifdef RTC_DEBUG
	printf( "rtc_write: %x:%x\n", addr, val );
#endif
	out8( addr, val );
}

#endif