xref: /openbmc/u-boot/drivers/rtc/ds164x.c (revision d81b27a2)
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_CMD_DATE)
41 
42 static uchar    rtc_read(unsigned int addr );
43 static void     rtc_write(unsigned int addr, uchar val);
44 
45 #define RTC_EPOCH                 2000	/* century */
46 
47 /*
48  * DS164x registers layout
49  */
50 #define RTC_BASE		( CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE )
51 
52 #define RTC_YEAR		( RTC_BASE + 0x07 )
53 #define RTC_MONTH		( RTC_BASE + 0x06 )
54 #define RTC_DAY_OF_MONTH	( RTC_BASE + 0x05 )
55 #define RTC_DAY_OF_WEEK		( RTC_BASE + 0x04 )
56 #define RTC_HOURS		( RTC_BASE + 0x03 )
57 #define RTC_MINUTES		( RTC_BASE + 0x02 )
58 #define RTC_SECONDS		( RTC_BASE + 0x01 )
59 #define RTC_CONTROL		( RTC_BASE + 0x00 )
60 
61 #define RTC_CONTROLA		RTC_CONTROL	/* W=bit6, R=bit5 */
62 #define   RTC_CA_WRITE		  0x80
63 #define   RTC_CA_READ		  0x40
64 #define RTC_CONTROLB		RTC_SECONDS	/* OSC=bit7       */
65 #define   RTC_CB_OSC_DISABLE	  0x80
66 #define RTC_CONTROLC		RTC_DAY_OF_WEEK	/* FT=bit6        */
67 #define   RTC_CC_FREQ_TEST	  0x40
68 
69 /* ------------------------------------------------------------------------- */
70 
71 int rtc_get( struct rtc_time *tmp )
72 {
73 	uchar sec, min, hour;
74 	uchar mday, wday, mon, year;
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 
90 	/* unlock clock registers after read */
91 	rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
92 
93 #ifdef RTC_DEBUG
94 	printf( "Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
95 		"hr: %02x min: %02x sec: %02x\n",
96 		year, mon, mday, wday,
97 		hour, min, sec );
98 #endif
99 	tmp->tm_sec  = bcd2bin( sec  & 0x7F );
100 	tmp->tm_min  = bcd2bin( min  & 0x7F );
101 	tmp->tm_hour = bcd2bin( hour & 0x3F );
102 	tmp->tm_mday = bcd2bin( mday & 0x3F );
103 	tmp->tm_mon  = bcd2bin( mon  & 0x1F );
104 	tmp->tm_wday = bcd2bin( wday & 0x07 );
105 
106 	/* glue year in century (2000) */
107 	tmp->tm_year = bcd2bin( year ) + RTC_EPOCH;
108 
109 	tmp->tm_yday = 0;
110 	tmp->tm_isdst= 0;
111 #ifdef RTC_DEBUG
112 	printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
113 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
114 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
115 #endif
116 
117 	return 0;
118 }
119 
120 int 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 	return 0;
148 }
149 
150 void rtc_reset (void)
151 {
152 	uchar reg_a, reg_b;
153 
154 	reg_a = rtc_read( RTC_CONTROLA );
155 	reg_b = rtc_read( RTC_CONTROLB );
156 
157 	if ( reg_b & RTC_CB_OSC_DISABLE )
158 	{
159 		printf( "real-time-clock was stopped. Now starting...\n" );
160 		reg_a |= RTC_CA_WRITE;
161 		reg_b &= ~RTC_CB_OSC_DISABLE;
162 
163 		rtc_write( RTC_CONTROLA, reg_a );
164 		rtc_write( RTC_CONTROLB, reg_b );
165 	}
166 
167 	/* make sure read/write clock register bits are cleared */
168 	reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
169 	rtc_write( RTC_CONTROLA, reg_a );
170 }
171 
172 /* ------------------------------------------------------------------------- */
173 
174 static uchar rtc_read( unsigned int addr )
175 {
176 	uchar val = *(volatile unsigned char*)(addr);
177 
178 #ifdef RTC_DEBUG
179 	printf( "rtc_read: %x:%x\n", addr, val );
180 #endif
181 	return( val );
182 }
183 
184 static void rtc_write( unsigned int addr, uchar val )
185 {
186 #ifdef RTC_DEBUG
187 	printf( "rtc_write: %x:%x\n", addr, val );
188 #endif
189 	*(volatile unsigned char*)(addr) = val;
190 }
191 
192 #endif
193