xref: /openbmc/u-boot/drivers/rtc/m41t11.c (revision 7d9b5bae)
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 CFG_I2C_RTC_ADDR 0x68
39 #if 0
40 #define CFG_M41T11_EXT_CENTURY_DATA
41 #else
42 #define CFG_M41T11_BASE_YEAR 2000
43 #endif
44 */
45 
46 #if defined(CFG_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE)
47 
48 static unsigned bcd2bin (uchar n)
49 {
50 	return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
51 }
52 
53 static unsigned char bin2bcd (unsigned int n)
54 {
55 	return (((n / 10) << 4) | (n % 10));
56 }
57 
58 
59 /* ------------------------------------------------------------------------- */
60 /*
61   these are simple defines for the chip local to here so they aren't too
62   verbose
63   DAY/DATE aren't nice but that is how they are on the data sheet
64 */
65 #define RTC_SEC_ADDR       0x0
66 #define RTC_MIN_ADDR       0x1
67 #define RTC_HOUR_ADDR      0x2
68 #define RTC_DAY_ADDR       0x3
69 #define RTC_DATE_ADDR      0x4
70 #define RTC_MONTH_ADDR     0x5
71 #define RTC_YEARS_ADDR     0x6
72 
73 #define RTC_REG_CNT        7
74 
75 #define RTC_CONTROL_ADDR   0x7
76 
77 
78 #ifndef CFG_M41T11_EXT_CENTURY_DATA
79 
80 #define REG_CNT            (RTC_REG_CNT+1)
81 
82 /*
83   you only get 00-99 for the year we will asume you
84   want from the year 2000 if you don't set the config
85 */
86 #ifndef CFG_M41T11_BASE_YEAR
87 #define CFG_M41T11_BASE_YEAR 2000
88 #endif
89 
90 #else
91 /* we will store extra year info in byte 9*/
92 #define M41T11_YEAR_DATA   0x8
93 #define M41T11_YEAR_SIZE   1
94 #define REG_CNT            (RTC_REG_CNT+1+M41T11_YEAR_SIZE)
95 #endif
96 
97 #define M41T11_STORAGE_SZ  (64-REG_CNT)
98 
99 int rtc_get (struct rtc_time *tmp)
100 {
101 	int rel = 0;
102 	uchar data[RTC_REG_CNT];
103 
104 	i2c_read(CFG_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
105 
106 	if( data[RTC_SEC_ADDR] & 0x80 ){
107 		printf( "m41t11 RTC Clock stopped!!!\n" );
108 		rel = -1;
109 	}
110 	tmp->tm_sec  = bcd2bin (data[RTC_SEC_ADDR]  & 0x7F);
111 	tmp->tm_min  = bcd2bin (data[RTC_MIN_ADDR]  & 0x7F);
112 	tmp->tm_hour = bcd2bin (data[RTC_HOUR_ADDR] & 0x3F);
113 	tmp->tm_mday = bcd2bin (data[RTC_DATE_ADDR] & 0x3F);
114 	tmp->tm_mon  = bcd2bin (data[RTC_MONTH_ADDR]& 0x1F);
115 #ifndef CFG_M41T11_EXT_CENTURY_DATA
116 	tmp->tm_year = CFG_M41T11_BASE_YEAR
117 		+ bcd2bin(data[RTC_YEARS_ADDR])
118 		+ ((data[RTC_HOUR_ADDR]&0x40) ? 100 : 0);
119 #else
120 	{
121 		unsigned char cent;
122 		i2c_read(CFG_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
123 		if( !(data[RTC_HOUR_ADDR] & 0x80) ){
124 			printf( "m41t11 RTC: cann't keep track of years without CEB set\n" );
125 			rel = -1;
126 		}
127 		if( (cent & 0x1) != ((data[RTC_HOUR_ADDR]&0x40)>>7) ){
128 			/*century flip store off new year*/
129 			cent += 1;
130 			i2c_write(CFG_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
131 		}
132 		tmp->tm_year =((int)cent*100)+bcd2bin(data[RTC_YEARS_ADDR]);
133 	}
134 #endif
135 	tmp->tm_wday = bcd2bin (data[RTC_DAY_ADDR]  & 0x07);
136 	tmp->tm_yday = 0;
137 	tmp->tm_isdst= 0;
138 
139 	debug ( "Get 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 	return rel;
144 }
145 
146 int rtc_set (struct rtc_time *tmp)
147 {
148 	uchar data[RTC_REG_CNT];
149 
150 	debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
151 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
152 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
153 
154 	data[RTC_SEC_ADDR]    = bin2bcd(tmp->tm_sec) &  0x7F;/*just in case*/
155 	data[RTC_MIN_ADDR]    = bin2bcd(tmp->tm_min);
156 	data[RTC_HOUR_ADDR]   = bin2bcd(tmp->tm_hour) & 0x3F;/*handle cent stuff later*/
157 	data[RTC_DATE_ADDR]   = bin2bcd(tmp->tm_mday) & 0x3F;
158 	data[RTC_MONTH_ADDR]  = bin2bcd(tmp->tm_mon);
159 	data[RTC_DAY_ADDR]    = bin2bcd(tmp->tm_wday) & 0x07;
160 
161 	data[RTC_HOUR_ADDR]   |= 0x80;/*we will always use CEB*/
162 
163 	data[RTC_YEARS_ADDR]  = bin2bcd(tmp->tm_year%100);/*same thing either way*/
164 #ifndef CFG_M41T11_EXT_CENTURY_DATA
165 	if( ((tmp->tm_year - CFG_M41T11_BASE_YEAR) > 200) ||
166 	    (tmp->tm_year < CFG_M41T11_BASE_YEAR) ){
167 		printf( "m41t11 RTC setting year out of range!!need recompile\n" );
168 	}
169 	data[RTC_HOUR_ADDR] |= (tmp->tm_year - CFG_M41T11_BASE_YEAR) > 100 ? 0x40 : 0;
170 #else
171 	{
172 		unsigned char cent;
173 		cent = tmp->tm_year ? tmp->tm_year / 100 : 0;
174 		data[RTC_HOUR_ADDR] |= (cent & 0x1) ? 0x40 : 0;
175 		i2c_write(CFG_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
176 	}
177 #endif
178 	i2c_write(CFG_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
179 
180 	return 0;
181 }
182 
183 void rtc_reset (void)
184 {
185 	unsigned char val;
186 	/* clear all control & status registers */
187 	i2c_read(CFG_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, 1);
188 	val = val & 0x7F;/*make sure we are running*/
189 	i2c_write(CFG_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, RTC_REG_CNT);
190 
191 	i2c_read(CFG_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
192 	val = val & 0x3F;/*turn off freq test keep calibration*/
193 	i2c_write(CFG_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
194 }
195 
196 int rtc_store(int addr, unsigned char* data, int size)
197 {
198 	/*don't let things wrap onto the time on a write*/
199 	if( (addr+size) >= M41T11_STORAGE_SZ )
200 		return 1;
201 	return i2c_write( CFG_I2C_RTC_ADDR, REG_CNT+addr, 1, data, size );
202 }
203 
204 int rtc_recall(int addr, unsigned char* data, int size)
205 {
206 	return i2c_read( CFG_I2C_RTC_ADDR, REG_CNT+addr, 1, data, size );
207 }
208 
209 #endif
210