xref: /openbmc/u-boot/drivers/rtc/ds1556.c (revision 419adbfb)
1 /*
2  * (C) Copyright 2002
3  * ARIO Data Networks, Inc. dchiu@ariodata.com
4  *
5  * modified for DS1556:
6  * Frank Panno <fpanno@delphintech.com>, Delphin Technology AG
7  *
8  * Based on MontaVista DS1743 code and U-Boot mc146818 code
9  *
10  * See file CREDITS for list of people who contributed to this
11  * project.
12  *
13  * This program is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU General Public License as
15  * published by the Free Software Foundation; either version 2 of
16  * the License, or (at your option) any later version.
17  *
18  * This program is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21  * GNU General Public License for more details.
22  *
23  * You should have received a copy of the GNU General Public License
24  * along with this program; if not, write to the Free Software
25  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
26  * MA 02111-1307 USA
27  */
28 
29 /*
30  * Date & Time support for the DS1556 RTC
31  */
32 
33 /*#define	RTC_DEBUG */
34 
35 #include <common.h>
36 #include <command.h>
37 #include <rtc.h>
38 
39 #if defined(CONFIG_CMD_DATE)
40 
41 static uchar rtc_read( unsigned int addr );
42 static void  rtc_write( unsigned int addr, uchar val);
43 
44 #define RTC_BASE		( CONFIG_SYS_NVRAM_SIZE + CONFIG_SYS_NVRAM_BASE_ADDR )
45 
46 #define RTC_YEAR		( RTC_BASE + 0xf )
47 #define RTC_MONTH		( RTC_BASE + 0xe )
48 #define RTC_DAY_OF_MONTH	( RTC_BASE + 0xd )
49 #define RTC_DAY_OF_WEEK		( RTC_BASE + 0xc )
50 #define RTC_HOURS		( RTC_BASE + 0xb )
51 #define RTC_MINUTES		( RTC_BASE + 0xa )
52 #define RTC_SECONDS		( RTC_BASE + 0x9 )
53 #define RTC_CENTURY		( RTC_BASE + 0x8 )
54 
55 #define RTC_CONTROLA		RTC_CENTURY
56 #define RTC_CONTROLB		RTC_SECONDS
57 #define RTC_CONTROLC		RTC_BASE
58 
59 #define RTC_CA_WRITE		0x80
60 #define RTC_CA_READ		0x40
61 
62 #define RTC_CB_OSC_DISABLE	0x80
63 
64 #define RTC_CC_BATTERY_FLAG	0x10
65 #define RTC_CC_FREQ_TEST	0x40
66 
67 /* ------------------------------------------------------------------------- */
68 
69 int rtc_get( struct rtc_time *tmp )
70 {
71 	uchar sec, min, hour;
72 	uchar mday, wday, mon, year;
73 
74 	int century;
75 
76 	uchar reg_a;
77 
78 	reg_a = rtc_read( RTC_CONTROLA );
79 	/* lock clock registers for read */
80 	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));
81 
82 	sec     = rtc_read( RTC_SECONDS );
83 	min     = rtc_read( RTC_MINUTES );
84 	hour    = rtc_read( RTC_HOURS );
85 	mday    = rtc_read( RTC_DAY_OF_MONTH );
86 	wday    = rtc_read( RTC_DAY_OF_WEEK );
87 	mon     = rtc_read( RTC_MONTH );
88 	year    = rtc_read( RTC_YEAR );
89 	century = rtc_read( RTC_CENTURY );
90 
91 	/* unlock clock registers after read */
92 	rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
93 
94 #ifdef RTC_DEBUG
95 	printf( "Get RTC year: %02x mon/cent: %02x mon: %02x mday: %02x wday: %02x "
96 		"hr: %02x min: %02x sec: %02x\n",
97 		year, century, mon, mday, wday,
98 		hour, min, sec );
99 #endif
100 	tmp->tm_sec  = bcd2bin( sec  & 0x7F );
101 	tmp->tm_min  = bcd2bin( min  & 0x7F );
102 	tmp->tm_hour = bcd2bin( hour & 0x3F );
103 	tmp->tm_mday = bcd2bin( mday & 0x3F );
104 	tmp->tm_mon  = bcd2bin( mon & 0x1F );
105 	tmp->tm_wday = bcd2bin( wday & 0x07 );
106 
107 	/* glue year from century and year in century */
108 	tmp->tm_year = bcd2bin( year ) +
109 		( bcd2bin( century & 0x3F ) * 100 );
110 
111 	tmp->tm_yday = 0;
112 	tmp->tm_isdst= 0;
113 #ifdef RTC_DEBUG
114 	printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
115 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
116 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
117 #endif
118 	return 0;
119 }
120 
121 int rtc_set( struct rtc_time *tmp )
122 {
123 	uchar reg_a;
124 #ifdef RTC_DEBUG
125 	printf( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
126 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
127 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
128 #endif
129 	/* lock clock registers for write */
130 	reg_a = rtc_read( RTC_CONTROLA );
131 	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));
132 
133 	rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));
134 
135 	rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
136 	rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
137 	rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
138 	rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
139 	rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));
140 
141 	/* break year up into century and year in century */
142 	rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
143 	rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 ));
144 
145 	/* unlock clock registers after read */
146 	rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));
147 
148 	return 0;
149 }
150 
151 void rtc_reset (void)
152 {
153 	uchar reg_a, reg_b, reg_c;
154 
155 	reg_a = rtc_read( RTC_CONTROLA );
156 	reg_b = rtc_read( RTC_CONTROLB );
157 
158 	if ( reg_b & RTC_CB_OSC_DISABLE )
159 	{
160 		printf( "real-time-clock was stopped. Now starting...\n" );
161 		reg_a |= RTC_CA_WRITE;
162 		reg_b &= ~RTC_CB_OSC_DISABLE;
163 
164 		rtc_write( RTC_CONTROLA, reg_a );
165 		rtc_write( RTC_CONTROLB, reg_b );
166 	}
167 
168 	/* make sure read/write clock register bits are cleared */
169 	reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
170 	rtc_write( RTC_CONTROLA, reg_a );
171 
172 	reg_c = rtc_read( RTC_CONTROLC );
173 	if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 )
174 		printf( "RTC battery low. Clock setting may not be reliable.\n" );
175 }
176 
177 /* ------------------------------------------------------------------------- */
178 
179 static uchar rtc_read( unsigned int addr )
180 {
181 	uchar val = *(volatile unsigned char*)(addr);
182 #ifdef RTC_DEBUG
183 	printf( "rtc_read: %x:%x\n", addr, val );
184 #endif
185 	return( val );
186 }
187 
188 static void rtc_write( unsigned int addr, uchar val )
189 {
190 #ifdef RTC_DEBUG
191 	printf( "rtc_write: %x:%x\n", addr, val );
192 #endif
193 	*(volatile unsigned char*)(addr) = val;
194 }
195 
196 #endif
197