xref: /openbmc/u-boot/drivers/rtc/ds164x.c (revision 53193a4f)
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  * SPDX-License-Identifier:	GPL-2.0+
11  */
12 
13 /*
14  * Date & Time support for the DS164x RTC
15  */
16 
17 /* #define	RTC_DEBUG */
18 
19 #include <common.h>
20 #include <command.h>
21 #include <rtc.h>
22 
23 
24 #if defined(CONFIG_CMD_DATE)
25 
26 static uchar    rtc_read(unsigned int addr );
27 static void     rtc_write(unsigned int addr, uchar val);
28 
29 #define RTC_EPOCH                 2000	/* century */
30 
31 /*
32  * DS164x registers layout
33  */
34 #define RTC_BASE		( CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE )
35 
36 #define RTC_YEAR		( RTC_BASE + 0x07 )
37 #define RTC_MONTH		( RTC_BASE + 0x06 )
38 #define RTC_DAY_OF_MONTH	( RTC_BASE + 0x05 )
39 #define RTC_DAY_OF_WEEK		( RTC_BASE + 0x04 )
40 #define RTC_HOURS		( RTC_BASE + 0x03 )
41 #define RTC_MINUTES		( RTC_BASE + 0x02 )
42 #define RTC_SECONDS		( RTC_BASE + 0x01 )
43 #define RTC_CONTROL		( RTC_BASE + 0x00 )
44 
45 #define RTC_CONTROLA		RTC_CONTROL	/* W=bit6, R=bit5 */
46 #define   RTC_CA_WRITE		  0x80
47 #define   RTC_CA_READ		  0x40
48 #define RTC_CONTROLB		RTC_SECONDS	/* OSC=bit7       */
49 #define   RTC_CB_OSC_DISABLE	  0x80
50 #define RTC_CONTROLC		RTC_DAY_OF_WEEK	/* FT=bit6        */
51 #define   RTC_CC_FREQ_TEST	  0x40
52 
53 /* ------------------------------------------------------------------------- */
54 
55 int rtc_get( struct rtc_time *tmp )
56 {
57 	uchar sec, min, hour;
58 	uchar mday, wday, mon, year;
59 
60 	uchar reg_a;
61 
62 	reg_a = rtc_read( RTC_CONTROLA );
63 	/* lock clock registers for read */
64 	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));
65 
66 	sec     = rtc_read( RTC_SECONDS );
67 	min     = rtc_read( RTC_MINUTES );
68 	hour    = rtc_read( RTC_HOURS );
69 	mday    = rtc_read( RTC_DAY_OF_MONTH );
70 	wday    = rtc_read( RTC_DAY_OF_WEEK );
71 	mon     = rtc_read( RTC_MONTH );
72 	year    = rtc_read( RTC_YEAR );
73 
74 	/* unlock clock registers after read */
75 	rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
76 
77 #ifdef RTC_DEBUG
78 	printf( "Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
79 		"hr: %02x min: %02x sec: %02x\n",
80 		year, mon, mday, wday,
81 		hour, min, sec );
82 #endif
83 	tmp->tm_sec  = bcd2bin( sec  & 0x7F );
84 	tmp->tm_min  = bcd2bin( min  & 0x7F );
85 	tmp->tm_hour = bcd2bin( hour & 0x3F );
86 	tmp->tm_mday = bcd2bin( mday & 0x3F );
87 	tmp->tm_mon  = bcd2bin( mon  & 0x1F );
88 	tmp->tm_wday = bcd2bin( wday & 0x07 );
89 
90 	/* glue year in century (2000) */
91 	tmp->tm_year = bcd2bin( year ) + RTC_EPOCH;
92 
93 	tmp->tm_yday = 0;
94 	tmp->tm_isdst= 0;
95 #ifdef RTC_DEBUG
96 	printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
97 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
98 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
99 #endif
100 
101 	return 0;
102 }
103 
104 int rtc_set( struct rtc_time *tmp )
105 {
106 	uchar reg_a;
107 
108 #ifdef RTC_DEBUG
109 	printf( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
110 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
111 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
112 #endif
113 	/* lock clock registers for write */
114 	reg_a = rtc_read( RTC_CONTROLA );
115 	rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));
116 
117 	rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));
118 
119 	rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
120 	rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
121 	rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
122 	rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
123 	rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));
124 
125 	/* break year in century */
126 	rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
127 
128 	/* unlock clock registers after read */
129 	rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));
130 
131 	return 0;
132 }
133 
134 void rtc_reset (void)
135 {
136 	uchar reg_a, reg_b;
137 
138 	reg_a = rtc_read( RTC_CONTROLA );
139 	reg_b = rtc_read( RTC_CONTROLB );
140 
141 	if ( reg_b & RTC_CB_OSC_DISABLE )
142 	{
143 		printf( "real-time-clock was stopped. Now starting...\n" );
144 		reg_a |= RTC_CA_WRITE;
145 		reg_b &= ~RTC_CB_OSC_DISABLE;
146 
147 		rtc_write( RTC_CONTROLA, reg_a );
148 		rtc_write( RTC_CONTROLB, reg_b );
149 	}
150 
151 	/* make sure read/write clock register bits are cleared */
152 	reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
153 	rtc_write( RTC_CONTROLA, reg_a );
154 }
155 
156 /* ------------------------------------------------------------------------- */
157 
158 static uchar rtc_read( unsigned int addr )
159 {
160 	uchar val = *(volatile unsigned char*)(addr);
161 
162 #ifdef RTC_DEBUG
163 	printf( "rtc_read: %x:%x\n", addr, val );
164 #endif
165 	return( val );
166 }
167 
168 static void rtc_write( unsigned int addr, uchar val )
169 {
170 #ifdef RTC_DEBUG
171 	printf( "rtc_write: %x:%x\n", addr, val );
172 #endif
173 	*(volatile unsigned char*)(addr) = val;
174 }
175 
176 #endif
177