xref: /openbmc/u-boot/drivers/rtc/m41t11.c (revision 85231c08)
1 /*
2  * (C) Copyright 2002
3  * Andrew May, Viasat Inc, amay@viasat.com
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 /*
9  * M41T11 Serial Access Timekeeper(R) SRAM
10  * can you believe a trademark on that?
11  */
12 
13 /* #define DEBUG 1 */
14 
15 #include <common.h>
16 #include <command.h>
17 #include <rtc.h>
18 #include <i2c.h>
19 
20 /*
21 	I Don't have an example config file but this
22 	is what should be done.
23 
24 #define CONFIG_RTC_M41T11 1
25 #define CONFIG_SYS_I2C_RTC_ADDR 0x68
26 #if 0
27 #define CONFIG_SYS_M41T11_EXT_CENTURY_DATA
28 #else
29 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
30 #endif
31 */
32 
33 #if defined(CONFIG_SYS_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE)
34 
35 /* ------------------------------------------------------------------------- */
36 /*
37   these are simple defines for the chip local to here so they aren't too
38   verbose
39   DAY/DATE aren't nice but that is how they are on the data sheet
40 */
41 #define RTC_SEC_ADDR       0x0
42 #define RTC_MIN_ADDR       0x1
43 #define RTC_HOUR_ADDR      0x2
44 #define RTC_DAY_ADDR       0x3
45 #define RTC_DATE_ADDR      0x4
46 #define RTC_MONTH_ADDR     0x5
47 #define RTC_YEARS_ADDR     0x6
48 
49 #define RTC_REG_CNT        7
50 
51 #define RTC_CONTROL_ADDR   0x7
52 
53 
54 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
55 
56 #define REG_CNT            (RTC_REG_CNT+1)
57 
58 /*
59   you only get 00-99 for the year we will asume you
60   want from the year 2000 if you don't set the config
61 */
62 #ifndef CONFIG_SYS_M41T11_BASE_YEAR
63 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
64 #endif
65 
66 #else
67 /* we will store extra year info in byte 9*/
68 #define M41T11_YEAR_DATA   0x8
69 #define M41T11_YEAR_SIZE   1
70 #define REG_CNT            (RTC_REG_CNT+1+M41T11_YEAR_SIZE)
71 #endif
72 
73 #define M41T11_STORAGE_SZ  (64-REG_CNT)
74 
75 int rtc_get (struct rtc_time *tmp)
76 {
77 	int rel = 0;
78 	uchar data[RTC_REG_CNT];
79 
80 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
81 
82 	if( data[RTC_SEC_ADDR] & 0x80 ){
83 		printf( "m41t11 RTC Clock stopped!!!\n" );
84 		rel = -1;
85 	}
86 	tmp->tm_sec  = bcd2bin (data[RTC_SEC_ADDR]  & 0x7F);
87 	tmp->tm_min  = bcd2bin (data[RTC_MIN_ADDR]  & 0x7F);
88 	tmp->tm_hour = bcd2bin (data[RTC_HOUR_ADDR] & 0x3F);
89 	tmp->tm_mday = bcd2bin (data[RTC_DATE_ADDR] & 0x3F);
90 	tmp->tm_mon  = bcd2bin (data[RTC_MONTH_ADDR]& 0x1F);
91 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
92 	tmp->tm_year = CONFIG_SYS_M41T11_BASE_YEAR
93 		+ bcd2bin(data[RTC_YEARS_ADDR])
94 		+ ((data[RTC_HOUR_ADDR]&0x40) ? 100 : 0);
95 #else
96 	{
97 		unsigned char cent;
98 		i2c_read(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
99 		if( !(data[RTC_HOUR_ADDR] & 0x80) ){
100 			printf( "m41t11 RTC: cann't keep track of years without CEB set\n" );
101 			rel = -1;
102 		}
103 		if( (cent & 0x1) != ((data[RTC_HOUR_ADDR]&0x40)>>7) ){
104 			/*century flip store off new year*/
105 			cent += 1;
106 			i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
107 		}
108 		tmp->tm_year =((int)cent*100)+bcd2bin(data[RTC_YEARS_ADDR]);
109 	}
110 #endif
111 	tmp->tm_wday = bcd2bin (data[RTC_DAY_ADDR]  & 0x07);
112 	tmp->tm_yday = 0;
113 	tmp->tm_isdst= 0;
114 
115 	debug ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
116 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
117 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
118 
119 	return rel;
120 }
121 
122 int rtc_set (struct rtc_time *tmp)
123 {
124 	uchar data[RTC_REG_CNT];
125 
126 	debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
127 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
128 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
129 
130 	data[RTC_SEC_ADDR]    = bin2bcd(tmp->tm_sec) &  0x7F;/*just in case*/
131 	data[RTC_MIN_ADDR]    = bin2bcd(tmp->tm_min);
132 	data[RTC_HOUR_ADDR]   = bin2bcd(tmp->tm_hour) & 0x3F;/*handle cent stuff later*/
133 	data[RTC_DATE_ADDR]   = bin2bcd(tmp->tm_mday) & 0x3F;
134 	data[RTC_MONTH_ADDR]  = bin2bcd(tmp->tm_mon);
135 	data[RTC_DAY_ADDR]    = bin2bcd(tmp->tm_wday) & 0x07;
136 
137 	data[RTC_HOUR_ADDR]   |= 0x80;/*we will always use CEB*/
138 
139 	data[RTC_YEARS_ADDR]  = bin2bcd(tmp->tm_year%100);/*same thing either way*/
140 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
141 	if( ((tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 200) ||
142 	    (tmp->tm_year < CONFIG_SYS_M41T11_BASE_YEAR) ){
143 		printf( "m41t11 RTC setting year out of range!!need recompile\n" );
144 	}
145 	data[RTC_HOUR_ADDR] |= (tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 100 ? 0x40 : 0;
146 #else
147 	{
148 		unsigned char cent;
149 		cent = tmp->tm_year ? tmp->tm_year / 100 : 0;
150 		data[RTC_HOUR_ADDR] |= (cent & 0x1) ? 0x40 : 0;
151 		i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
152 	}
153 #endif
154 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
155 
156 	return 0;
157 }
158 
159 void rtc_reset (void)
160 {
161 	unsigned char val;
162 	/* clear all control & status registers */
163 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, 1);
164 	val = val & 0x7F;/*make sure we are running*/
165 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, RTC_REG_CNT);
166 
167 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
168 	val = val & 0x3F;/*turn off freq test keep calibration*/
169 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
170 }
171 #endif
172