xref: /openbmc/u-boot/drivers/rtc/m41t11.c (revision d81b27a2)
1 /*
2  * (C) Copyright 2002
3  * Andrew May, Viasat Inc, amay@viasat.com
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation; either version 2 of
8  * the License, or (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
18  * MA 02111-1307 USA
19  */
20 
21 /*
22  * M41T11 Serial Access Timekeeper(R) SRAM
23  * can you believe a trademark on that?
24  */
25 
26 /* #define DEBUG 1 */
27 
28 #include <common.h>
29 #include <command.h>
30 #include <rtc.h>
31 #include <i2c.h>
32 
33 /*
34 	I Don't have an example config file but this
35 	is what should be done.
36 
37 #define CONFIG_RTC_M41T11 1
38 #define CONFIG_SYS_I2C_RTC_ADDR 0x68
39 #if 0
40 #define CONFIG_SYS_M41T11_EXT_CENTURY_DATA
41 #else
42 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
43 #endif
44 */
45 
46 #if defined(CONFIG_SYS_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE)
47 
48 /* ------------------------------------------------------------------------- */
49 /*
50   these are simple defines for the chip local to here so they aren't too
51   verbose
52   DAY/DATE aren't nice but that is how they are on the data sheet
53 */
54 #define RTC_SEC_ADDR       0x0
55 #define RTC_MIN_ADDR       0x1
56 #define RTC_HOUR_ADDR      0x2
57 #define RTC_DAY_ADDR       0x3
58 #define RTC_DATE_ADDR      0x4
59 #define RTC_MONTH_ADDR     0x5
60 #define RTC_YEARS_ADDR     0x6
61 
62 #define RTC_REG_CNT        7
63 
64 #define RTC_CONTROL_ADDR   0x7
65 
66 
67 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
68 
69 #define REG_CNT            (RTC_REG_CNT+1)
70 
71 /*
72   you only get 00-99 for the year we will asume you
73   want from the year 2000 if you don't set the config
74 */
75 #ifndef CONFIG_SYS_M41T11_BASE_YEAR
76 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
77 #endif
78 
79 #else
80 /* we will store extra year info in byte 9*/
81 #define M41T11_YEAR_DATA   0x8
82 #define M41T11_YEAR_SIZE   1
83 #define REG_CNT            (RTC_REG_CNT+1+M41T11_YEAR_SIZE)
84 #endif
85 
86 #define M41T11_STORAGE_SZ  (64-REG_CNT)
87 
88 int rtc_get (struct rtc_time *tmp)
89 {
90 	int rel = 0;
91 	uchar data[RTC_REG_CNT];
92 
93 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
94 
95 	if( data[RTC_SEC_ADDR] & 0x80 ){
96 		printf( "m41t11 RTC Clock stopped!!!\n" );
97 		rel = -1;
98 	}
99 	tmp->tm_sec  = bcd2bin (data[RTC_SEC_ADDR]  & 0x7F);
100 	tmp->tm_min  = bcd2bin (data[RTC_MIN_ADDR]  & 0x7F);
101 	tmp->tm_hour = bcd2bin (data[RTC_HOUR_ADDR] & 0x3F);
102 	tmp->tm_mday = bcd2bin (data[RTC_DATE_ADDR] & 0x3F);
103 	tmp->tm_mon  = bcd2bin (data[RTC_MONTH_ADDR]& 0x1F);
104 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
105 	tmp->tm_year = CONFIG_SYS_M41T11_BASE_YEAR
106 		+ bcd2bin(data[RTC_YEARS_ADDR])
107 		+ ((data[RTC_HOUR_ADDR]&0x40) ? 100 : 0);
108 #else
109 	{
110 		unsigned char cent;
111 		i2c_read(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
112 		if( !(data[RTC_HOUR_ADDR] & 0x80) ){
113 			printf( "m41t11 RTC: cann't keep track of years without CEB set\n" );
114 			rel = -1;
115 		}
116 		if( (cent & 0x1) != ((data[RTC_HOUR_ADDR]&0x40)>>7) ){
117 			/*century flip store off new year*/
118 			cent += 1;
119 			i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
120 		}
121 		tmp->tm_year =((int)cent*100)+bcd2bin(data[RTC_YEARS_ADDR]);
122 	}
123 #endif
124 	tmp->tm_wday = bcd2bin (data[RTC_DAY_ADDR]  & 0x07);
125 	tmp->tm_yday = 0;
126 	tmp->tm_isdst= 0;
127 
128 	debug ( "Get 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 
132 	return rel;
133 }
134 
135 int rtc_set (struct rtc_time *tmp)
136 {
137 	uchar data[RTC_REG_CNT];
138 
139 	debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
140 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
141 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
142 
143 	data[RTC_SEC_ADDR]    = bin2bcd(tmp->tm_sec) &  0x7F;/*just in case*/
144 	data[RTC_MIN_ADDR]    = bin2bcd(tmp->tm_min);
145 	data[RTC_HOUR_ADDR]   = bin2bcd(tmp->tm_hour) & 0x3F;/*handle cent stuff later*/
146 	data[RTC_DATE_ADDR]   = bin2bcd(tmp->tm_mday) & 0x3F;
147 	data[RTC_MONTH_ADDR]  = bin2bcd(tmp->tm_mon);
148 	data[RTC_DAY_ADDR]    = bin2bcd(tmp->tm_wday) & 0x07;
149 
150 	data[RTC_HOUR_ADDR]   |= 0x80;/*we will always use CEB*/
151 
152 	data[RTC_YEARS_ADDR]  = bin2bcd(tmp->tm_year%100);/*same thing either way*/
153 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
154 	if( ((tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 200) ||
155 	    (tmp->tm_year < CONFIG_SYS_M41T11_BASE_YEAR) ){
156 		printf( "m41t11 RTC setting year out of range!!need recompile\n" );
157 	}
158 	data[RTC_HOUR_ADDR] |= (tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 100 ? 0x40 : 0;
159 #else
160 	{
161 		unsigned char cent;
162 		cent = tmp->tm_year ? tmp->tm_year / 100 : 0;
163 		data[RTC_HOUR_ADDR] |= (cent & 0x1) ? 0x40 : 0;
164 		i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
165 	}
166 #endif
167 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
168 
169 	return 0;
170 }
171 
172 void rtc_reset (void)
173 {
174 	unsigned char val;
175 	/* clear all control & status registers */
176 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, 1);
177 	val = val & 0x7F;/*make sure we are running*/
178 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, RTC_REG_CNT);
179 
180 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
181 	val = val & 0x3F;/*turn off freq test keep calibration*/
182 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
183 }
184 #endif
185