xref: /openbmc/u-boot/drivers/rtc/ds164x.c (revision 415a613b)
1 /*
2  * (C) Copyright 2002
3  * ARIO Data Networks, Inc. dchiu@ariodata.com
4  *
5  * modified for DS164x:
6  * The LEOX team <team@leox.org>, http://www.leox.org
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 DS164x 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_DS164x) && 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_EPOCH                 2000	/* century */
48 
49 /*
50  * DS164x registers layout
51  */
52 #define RTC_BASE		( CFG_NVRAM_BASE_ADDR + CFG_NVRAM_SIZE )
53 
54 #define RTC_YEAR		( RTC_BASE + 0x07 )
55 #define RTC_MONTH		( RTC_BASE + 0x06 )
56 #define RTC_DAY_OF_MONTH	( RTC_BASE + 0x05 )
57 #define RTC_DAY_OF_WEEK		( RTC_BASE + 0x04 )
58 #define RTC_HOURS		( RTC_BASE + 0x03 )
59 #define RTC_MINUTES		( RTC_BASE + 0x02 )
60 #define RTC_SECONDS		( RTC_BASE + 0x01 )
61 #define RTC_CONTROL		( RTC_BASE + 0x00 )
62 
63 #define RTC_CONTROLA		RTC_CONTROL	/* W=bit6, R=bit5 */
64 #define   RTC_CA_WRITE		  0x80
65 #define   RTC_CA_READ		  0x40
66 #define RTC_CONTROLB		RTC_SECONDS	/* OSC=bit7       */
67 #define   RTC_CB_OSC_DISABLE	  0x80
68 #define RTC_CONTROLC		RTC_DAY_OF_WEEK	/* FT=bit6        */
69 #define   RTC_CC_FREQ_TEST	  0x40
70 
71 /* ------------------------------------------------------------------------- */
72 
73 void rtc_get( struct rtc_time *tmp )
74 {
75 	uchar sec, min, hour;
76 	uchar mday, wday, mon, year;
77 
78 	uchar reg_a;
79 
80 	reg_a = rtc_read( RTC_CONTROLA );
81 	/* lock clock registers for read */
82 	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));
83 
84 	sec     = rtc_read( RTC_SECONDS );
85 	min     = rtc_read( RTC_MINUTES );
86 	hour    = rtc_read( RTC_HOURS );
87 	mday    = rtc_read( RTC_DAY_OF_MONTH );
88 	wday    = rtc_read( RTC_DAY_OF_WEEK );
89 	mon     = rtc_read( RTC_MONTH );
90 	year    = rtc_read( RTC_YEAR );
91 
92 	/* unlock clock registers after read */
93 	rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
94 
95 #ifdef RTC_DEBUG
96 	printf( "Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
97 		"hr: %02x min: %02x sec: %02x\n",
98 		year, mon, mday, wday,
99 		hour, min, sec );
100 #endif
101 	tmp->tm_sec  = bcd2bin( sec  & 0x7F );
102 	tmp->tm_min  = bcd2bin( min  & 0x7F );
103 	tmp->tm_hour = bcd2bin( hour & 0x3F );
104 	tmp->tm_mday = bcd2bin( mday & 0x3F );
105 	tmp->tm_mon  = bcd2bin( mon  & 0x1F );
106 	tmp->tm_wday = bcd2bin( wday & 0x07 );
107 
108 	/* glue year in century (2000) */
109 	tmp->tm_year = bcd2bin( year ) + RTC_EPOCH;
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 }
119 
120 void rtc_set( struct rtc_time *tmp )
121 {
122 	uchar reg_a;
123 
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 in century */
142 	rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
143 
144 	/* unlock clock registers after read */
145 	rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));
146 }
147 
148 void rtc_reset (void)
149 {
150 	uchar reg_a, reg_b;
151 
152 	reg_a = rtc_read( RTC_CONTROLA );
153 	reg_b = rtc_read( RTC_CONTROLB );
154 
155 	if ( reg_b & RTC_CB_OSC_DISABLE )
156 	{
157 		printf( "real-time-clock was stopped. Now starting...\n" );
158 		reg_a |= RTC_CA_WRITE;
159 		reg_b &= ~RTC_CB_OSC_DISABLE;
160 
161 		rtc_write( RTC_CONTROLA, reg_a );
162 		rtc_write( RTC_CONTROLB, reg_b );
163 	}
164 
165 	/* make sure read/write clock register bits are cleared */
166 	reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
167 	rtc_write( RTC_CONTROLA, reg_a );
168 }
169 
170 /* ------------------------------------------------------------------------- */
171 
172 static uchar rtc_read( unsigned int addr )
173 {
174 	uchar val = *(volatile unsigned char*)(addr);
175 
176 #ifdef RTC_DEBUG
177 	printf( "rtc_read: %x:%x\n", addr, val );
178 #endif
179 	return( val );
180 }
181 
182 static void rtc_write( unsigned int addr, uchar val )
183 {
184 #ifdef RTC_DEBUG
185 	printf( "rtc_write: %x:%x\n", addr, val );
186 #endif
187 	*(volatile unsigned char*)(addr) = val;
188 }
189 
190 static unsigned bcd2bin (uchar n)
191 {
192 	return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
193 }
194 
195 static unsigned char bin2bcd (unsigned int n)
196 {
197 	return (((n / 10) << 4) | (n % 10));
198 }
199 
200 #endif
201