xref: /openbmc/u-boot/drivers/rtc/m41t11.c (revision d66ff4ba)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2002
4  * Andrew May, Viasat Inc, amay@viasat.com
5  */
6 
7 /*
8  * M41T11 Serial Access Timekeeper(R) SRAM
9  * can you believe a trademark on that?
10  */
11 
12 /* #define DEBUG 1 */
13 
14 #include <common.h>
15 #include <command.h>
16 #include <rtc.h>
17 #include <i2c.h>
18 
19 /*
20 	I Don't have an example config file but this
21 	is what should be done.
22 
23 #define CONFIG_RTC_M41T11 1
24 #define CONFIG_SYS_I2C_RTC_ADDR 0x68
25 #if 0
26 #define CONFIG_SYS_M41T11_EXT_CENTURY_DATA
27 #else
28 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
29 #endif
30 */
31 
32 /* ------------------------------------------------------------------------- */
33 /*
34   these are simple defines for the chip local to here so they aren't too
35   verbose
36   DAY/DATE aren't nice but that is how they are on the data sheet
37 */
38 #define RTC_SEC_ADDR       0x0
39 #define RTC_MIN_ADDR       0x1
40 #define RTC_HOUR_ADDR      0x2
41 #define RTC_DAY_ADDR       0x3
42 #define RTC_DATE_ADDR      0x4
43 #define RTC_MONTH_ADDR     0x5
44 #define RTC_YEARS_ADDR     0x6
45 
46 #define RTC_REG_CNT        7
47 
48 #define RTC_CONTROL_ADDR   0x7
49 
50 
51 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
52 
53 #define REG_CNT            (RTC_REG_CNT+1)
54 
55 /*
56   you only get 00-99 for the year we will asume you
57   want from the year 2000 if you don't set the config
58 */
59 #ifndef CONFIG_SYS_M41T11_BASE_YEAR
60 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
61 #endif
62 
63 #else
64 /* we will store extra year info in byte 9*/
65 #define M41T11_YEAR_DATA   0x8
66 #define M41T11_YEAR_SIZE   1
67 #define REG_CNT            (RTC_REG_CNT+1+M41T11_YEAR_SIZE)
68 #endif
69 
70 #define M41T11_STORAGE_SZ  (64-REG_CNT)
71 
72 int rtc_get (struct rtc_time *tmp)
73 {
74 	int rel = 0;
75 	uchar data[RTC_REG_CNT];
76 
77 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
78 
79 	if( data[RTC_SEC_ADDR] & 0x80 ){
80 		printf( "m41t11 RTC Clock stopped!!!\n" );
81 		rel = -1;
82 	}
83 	tmp->tm_sec  = bcd2bin (data[RTC_SEC_ADDR]  & 0x7F);
84 	tmp->tm_min  = bcd2bin (data[RTC_MIN_ADDR]  & 0x7F);
85 	tmp->tm_hour = bcd2bin (data[RTC_HOUR_ADDR] & 0x3F);
86 	tmp->tm_mday = bcd2bin (data[RTC_DATE_ADDR] & 0x3F);
87 	tmp->tm_mon  = bcd2bin (data[RTC_MONTH_ADDR]& 0x1F);
88 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
89 	tmp->tm_year = CONFIG_SYS_M41T11_BASE_YEAR
90 		+ bcd2bin(data[RTC_YEARS_ADDR])
91 		+ ((data[RTC_HOUR_ADDR]&0x40) ? 100 : 0);
92 #else
93 	{
94 		unsigned char cent;
95 		i2c_read(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
96 		if( !(data[RTC_HOUR_ADDR] & 0x80) ){
97 			printf( "m41t11 RTC: cann't keep track of years without CEB set\n" );
98 			rel = -1;
99 		}
100 		if( (cent & 0x1) != ((data[RTC_HOUR_ADDR]&0x40)>>7) ){
101 			/*century flip store off new year*/
102 			cent += 1;
103 			i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
104 		}
105 		tmp->tm_year =((int)cent*100)+bcd2bin(data[RTC_YEARS_ADDR]);
106 	}
107 #endif
108 	tmp->tm_wday = bcd2bin (data[RTC_DAY_ADDR]  & 0x07);
109 	tmp->tm_yday = 0;
110 	tmp->tm_isdst= 0;
111 
112 	debug ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
113 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
114 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
115 
116 	return rel;
117 }
118 
119 int rtc_set (struct rtc_time *tmp)
120 {
121 	uchar data[RTC_REG_CNT];
122 
123 	debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
124 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
125 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
126 
127 	data[RTC_SEC_ADDR]    = bin2bcd(tmp->tm_sec) &  0x7F;/*just in case*/
128 	data[RTC_MIN_ADDR]    = bin2bcd(tmp->tm_min);
129 	data[RTC_HOUR_ADDR]   = bin2bcd(tmp->tm_hour) & 0x3F;/*handle cent stuff later*/
130 	data[RTC_DATE_ADDR]   = bin2bcd(tmp->tm_mday) & 0x3F;
131 	data[RTC_MONTH_ADDR]  = bin2bcd(tmp->tm_mon);
132 	data[RTC_DAY_ADDR]    = bin2bcd(tmp->tm_wday) & 0x07;
133 
134 	data[RTC_HOUR_ADDR]   |= 0x80;/*we will always use CEB*/
135 
136 	data[RTC_YEARS_ADDR]  = bin2bcd(tmp->tm_year%100);/*same thing either way*/
137 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
138 	if( ((tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 200) ||
139 	    (tmp->tm_year < CONFIG_SYS_M41T11_BASE_YEAR) ){
140 		printf( "m41t11 RTC setting year out of range!!need recompile\n" );
141 	}
142 	data[RTC_HOUR_ADDR] |= (tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 100 ? 0x40 : 0;
143 #else
144 	{
145 		unsigned char cent;
146 		cent = tmp->tm_year ? tmp->tm_year / 100 : 0;
147 		data[RTC_HOUR_ADDR] |= (cent & 0x1) ? 0x40 : 0;
148 		i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
149 	}
150 #endif
151 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
152 
153 	return 0;
154 }
155 
156 void rtc_reset (void)
157 {
158 	unsigned char val;
159 	/* clear all control & status registers */
160 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, 1);
161 	val = val & 0x7F;/*make sure we are running*/
162 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, RTC_REG_CNT);
163 
164 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
165 	val = val & 0x3F;/*turn off freq test keep calibration*/
166 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
167 }
168