xref: /openbmc/u-boot/drivers/rtc/ds1556.c (revision 35546f6f2014282cc4f9772324b5588bd44a2938)
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   * SPDX-License-Identifier:	GPL-2.0+
11   */
12  
13  /*
14   * Date & Time support for the DS1556 RTC
15   */
16  
17  /*#define	RTC_DEBUG */
18  
19  #include <common.h>
20  #include <command.h>
21  #include <rtc.h>
22  
23  #if defined(CONFIG_CMD_DATE)
24  
25  static uchar rtc_read( unsigned int addr );
26  static void  rtc_write( unsigned int addr, uchar val);
27  
28  #define RTC_BASE		( CONFIG_SYS_NVRAM_SIZE + CONFIG_SYS_NVRAM_BASE_ADDR )
29  
30  #define RTC_YEAR		( RTC_BASE + 0xf )
31  #define RTC_MONTH		( RTC_BASE + 0xe )
32  #define RTC_DAY_OF_MONTH	( RTC_BASE + 0xd )
33  #define RTC_DAY_OF_WEEK		( RTC_BASE + 0xc )
34  #define RTC_HOURS		( RTC_BASE + 0xb )
35  #define RTC_MINUTES		( RTC_BASE + 0xa )
36  #define RTC_SECONDS		( RTC_BASE + 0x9 )
37  #define RTC_CENTURY		( RTC_BASE + 0x8 )
38  
39  #define RTC_CONTROLA		RTC_CENTURY
40  #define RTC_CONTROLB		RTC_SECONDS
41  #define RTC_CONTROLC		RTC_BASE
42  
43  #define RTC_CA_WRITE		0x80
44  #define RTC_CA_READ		0x40
45  
46  #define RTC_CB_OSC_DISABLE	0x80
47  
48  #define RTC_CC_BATTERY_FLAG	0x10
49  #define RTC_CC_FREQ_TEST	0x40
50  
51  /* ------------------------------------------------------------------------- */
52  
53  int rtc_get( struct rtc_time *tmp )
54  {
55  	uchar sec, min, hour;
56  	uchar mday, wday, mon, year;
57  
58  	int century;
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  	century = rtc_read( RTC_CENTURY );
74  
75  	/* unlock clock registers after read */
76  	rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
77  
78  #ifdef RTC_DEBUG
79  	printf( "Get RTC year: %02x mon/cent: %02x mon: %02x mday: %02x wday: %02x "
80  		"hr: %02x min: %02x sec: %02x\n",
81  		year, century, mon, mday, wday,
82  		hour, min, sec );
83  #endif
84  	tmp->tm_sec  = bcd2bin( sec  & 0x7F );
85  	tmp->tm_min  = bcd2bin( min  & 0x7F );
86  	tmp->tm_hour = bcd2bin( hour & 0x3F );
87  	tmp->tm_mday = bcd2bin( mday & 0x3F );
88  	tmp->tm_mon  = bcd2bin( mon & 0x1F );
89  	tmp->tm_wday = bcd2bin( wday & 0x07 );
90  
91  	/* glue year from century and year in century */
92  	tmp->tm_year = bcd2bin( year ) +
93  		( bcd2bin( century & 0x3F ) * 100 );
94  
95  	tmp->tm_yday = 0;
96  	tmp->tm_isdst= 0;
97  #ifdef RTC_DEBUG
98  	printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
99  		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
100  		tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
101  #endif
102  	return 0;
103  }
104  
105  int rtc_set( struct rtc_time *tmp )
106  {
107  	uchar reg_a;
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 up into century and year in century */
126  	rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
127  	rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 ));
128  
129  	/* unlock clock registers after read */
130  	rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));
131  
132  	return 0;
133  }
134  
135  void rtc_reset (void)
136  {
137  	uchar reg_a, reg_b, reg_c;
138  
139  	reg_a = rtc_read( RTC_CONTROLA );
140  	reg_b = rtc_read( RTC_CONTROLB );
141  
142  	if ( reg_b & RTC_CB_OSC_DISABLE )
143  	{
144  		printf( "real-time-clock was stopped. Now starting...\n" );
145  		reg_a |= RTC_CA_WRITE;
146  		reg_b &= ~RTC_CB_OSC_DISABLE;
147  
148  		rtc_write( RTC_CONTROLA, reg_a );
149  		rtc_write( RTC_CONTROLB, reg_b );
150  	}
151  
152  	/* make sure read/write clock register bits are cleared */
153  	reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
154  	rtc_write( RTC_CONTROLA, reg_a );
155  
156  	reg_c = rtc_read( RTC_CONTROLC );
157  	if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 )
158  		printf( "RTC battery low. Clock setting may not be reliable.\n" );
159  }
160  
161  /* ------------------------------------------------------------------------- */
162  
163  static uchar rtc_read( unsigned int addr )
164  {
165  	uchar val = *(volatile unsigned char*)(addr);
166  #ifdef RTC_DEBUG
167  	printf( "rtc_read: %x:%x\n", addr, val );
168  #endif
169  	return( val );
170  }
171  
172  static void rtc_write( unsigned int addr, uchar val )
173  {
174  #ifdef RTC_DEBUG
175  	printf( "rtc_write: %x:%x\n", addr, val );
176  #endif
177  	*(volatile unsigned char*)(addr) = val;
178  }
179  
180  #endif
181