xref: /openbmc/u-boot/drivers/rtc/ds1556.c (revision c0559be3)
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 
40 #if defined(CONFIG_RTC_DS1556) && defined(CONFIG_CMD_DATE)
41 
42 static uchar rtc_read( unsigned int addr );
43 static void  rtc_write( unsigned int addr, uchar val);
44 static uchar bin2bcd   (unsigned int n);
45 static unsigned bcd2bin(uchar c);
46 
47 #define RTC_BASE		( CFG_NVRAM_SIZE + CFG_NVRAM_BASE_ADDR )
48 
49 #define RTC_YEAR		( RTC_BASE + 0xf )
50 #define RTC_MONTH		( RTC_BASE + 0xe )
51 #define RTC_DAY_OF_MONTH	( RTC_BASE + 0xd )
52 #define RTC_DAY_OF_WEEK		( RTC_BASE + 0xc )
53 #define RTC_HOURS		( RTC_BASE + 0xb )
54 #define RTC_MINUTES		( RTC_BASE + 0xa )
55 #define RTC_SECONDS		( RTC_BASE + 0x9 )
56 #define RTC_CENTURY		( RTC_BASE + 0x8 )
57 
58 #define RTC_CONTROLA		RTC_CENTURY
59 #define RTC_CONTROLB		RTC_SECONDS
60 #define RTC_CONTROLC		RTC_BASE
61 
62 #define RTC_CA_WRITE		0x80
63 #define RTC_CA_READ		0x40
64 
65 #define RTC_CB_OSC_DISABLE	0x80
66 
67 #define RTC_CC_BATTERY_FLAG	0x10
68 #define RTC_CC_FREQ_TEST	0x40
69 
70 /* ------------------------------------------------------------------------- */
71 
72 int rtc_get( struct rtc_time *tmp )
73 {
74 	uchar sec, min, hour;
75 	uchar mday, wday, mon, year;
76 
77 	int century;
78 
79 	uchar reg_a;
80 
81 	reg_a = rtc_read( RTC_CONTROLA );
82 	/* lock clock registers for read */
83 	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));
84 
85 	sec     = rtc_read( RTC_SECONDS );
86 	min     = rtc_read( RTC_MINUTES );
87 	hour    = rtc_read( RTC_HOURS );
88 	mday    = rtc_read( RTC_DAY_OF_MONTH );
89 	wday    = rtc_read( RTC_DAY_OF_WEEK );
90 	mon     = rtc_read( RTC_MONTH );
91 	year    = rtc_read( RTC_YEAR );
92 	century = rtc_read( RTC_CENTURY );
93 
94 	/* unlock clock registers after read */
95 	rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
96 
97 #ifdef RTC_DEBUG
98 	printf( "Get RTC year: %02x mon/cent: %02x mon: %02x mday: %02x wday: %02x "
99 		"hr: %02x min: %02x sec: %02x\n",
100 		year, century, mon, mday, wday,
101 		hour, min, sec );
102 #endif
103 	tmp->tm_sec  = bcd2bin( sec  & 0x7F );
104 	tmp->tm_min  = bcd2bin( min  & 0x7F );
105 	tmp->tm_hour = bcd2bin( hour & 0x3F );
106 	tmp->tm_mday = bcd2bin( mday & 0x3F );
107 	tmp->tm_mon  = bcd2bin( mon & 0x1F );
108 	tmp->tm_wday = bcd2bin( wday & 0x07 );
109 
110 	/* glue year from century and year in century */
111 	tmp->tm_year = bcd2bin( year ) +
112 		( bcd2bin( century & 0x3F ) * 100 );
113 
114 	tmp->tm_yday = 0;
115 	tmp->tm_isdst= 0;
116 #ifdef RTC_DEBUG
117 	printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
118 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
119 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
120 #endif
121 	return 0;
122 }
123 
124 void rtc_set( struct rtc_time *tmp )
125 {
126 	uchar reg_a;
127 #ifdef RTC_DEBUG
128 	printf( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
129 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
130 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
131 #endif
132 	/* lock clock registers for write */
133 	reg_a = rtc_read( RTC_CONTROLA );
134 	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));
135 
136 	rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));
137 
138 	rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
139 	rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
140 	rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
141 	rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
142 	rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));
143 
144 	/* break year up into century and year in century */
145 	rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
146 	rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 ));
147 
148 	/* unlock clock registers after read */
149 	rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));
150 }
151 
152 void rtc_reset (void)
153 {
154 	uchar reg_a, reg_b, reg_c;
155 
156 	reg_a = rtc_read( RTC_CONTROLA );
157 	reg_b = rtc_read( RTC_CONTROLB );
158 
159 	if ( reg_b & RTC_CB_OSC_DISABLE )
160 	{
161 		printf( "real-time-clock was stopped. Now starting...\n" );
162 		reg_a |= RTC_CA_WRITE;
163 		reg_b &= ~RTC_CB_OSC_DISABLE;
164 
165 		rtc_write( RTC_CONTROLA, reg_a );
166 		rtc_write( RTC_CONTROLB, reg_b );
167 	}
168 
169 	/* make sure read/write clock register bits are cleared */
170 	reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
171 	rtc_write( RTC_CONTROLA, reg_a );
172 
173 	reg_c = rtc_read( RTC_CONTROLC );
174 	if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 )
175 		printf( "RTC battery low. Clock setting may not be reliable.\n" );
176 }
177 
178 /* ------------------------------------------------------------------------- */
179 
180 static uchar rtc_read( unsigned int addr )
181 {
182 	uchar val = *(volatile unsigned char*)(addr);
183 #ifdef RTC_DEBUG
184 	printf( "rtc_read: %x:%x\n", addr, val );
185 #endif
186 	return( val );
187 }
188 
189 static void rtc_write( unsigned int addr, uchar val )
190 {
191 #ifdef RTC_DEBUG
192 	printf( "rtc_write: %x:%x\n", addr, val );
193 #endif
194 	*(volatile unsigned char*)(addr) = val;
195 }
196 
197 static unsigned bcd2bin (uchar n)
198 {
199 	return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
200 }
201 
202 static unsigned char bin2bcd (unsigned int n)
203 {
204 	return (((n / 10) << 4) | (n % 10));
205 }
206 
207 #endif
208