xref: /openbmc/u-boot/drivers/rtc/m41t11.c (revision 8ee59472)
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 #if defined(CONFIG_SYS_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE)
33 
34 /* ------------------------------------------------------------------------- */
35 /*
36   these are simple defines for the chip local to here so they aren't too
37   verbose
38   DAY/DATE aren't nice but that is how they are on the data sheet
39 */
40 #define RTC_SEC_ADDR       0x0
41 #define RTC_MIN_ADDR       0x1
42 #define RTC_HOUR_ADDR      0x2
43 #define RTC_DAY_ADDR       0x3
44 #define RTC_DATE_ADDR      0x4
45 #define RTC_MONTH_ADDR     0x5
46 #define RTC_YEARS_ADDR     0x6
47 
48 #define RTC_REG_CNT        7
49 
50 #define RTC_CONTROL_ADDR   0x7
51 
52 
53 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
54 
55 #define REG_CNT            (RTC_REG_CNT+1)
56 
57 /*
58   you only get 00-99 for the year we will asume you
59   want from the year 2000 if you don't set the config
60 */
61 #ifndef CONFIG_SYS_M41T11_BASE_YEAR
62 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
63 #endif
64 
65 #else
66 /* we will store extra year info in byte 9*/
67 #define M41T11_YEAR_DATA   0x8
68 #define M41T11_YEAR_SIZE   1
69 #define REG_CNT            (RTC_REG_CNT+1+M41T11_YEAR_SIZE)
70 #endif
71 
72 #define M41T11_STORAGE_SZ  (64-REG_CNT)
73 
74 int rtc_get (struct rtc_time *tmp)
75 {
76 	int rel = 0;
77 	uchar data[RTC_REG_CNT];
78 
79 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
80 
81 	if( data[RTC_SEC_ADDR] & 0x80 ){
82 		printf( "m41t11 RTC Clock stopped!!!\n" );
83 		rel = -1;
84 	}
85 	tmp->tm_sec  = bcd2bin (data[RTC_SEC_ADDR]  & 0x7F);
86 	tmp->tm_min  = bcd2bin (data[RTC_MIN_ADDR]  & 0x7F);
87 	tmp->tm_hour = bcd2bin (data[RTC_HOUR_ADDR] & 0x3F);
88 	tmp->tm_mday = bcd2bin (data[RTC_DATE_ADDR] & 0x3F);
89 	tmp->tm_mon  = bcd2bin (data[RTC_MONTH_ADDR]& 0x1F);
90 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
91 	tmp->tm_year = CONFIG_SYS_M41T11_BASE_YEAR
92 		+ bcd2bin(data[RTC_YEARS_ADDR])
93 		+ ((data[RTC_HOUR_ADDR]&0x40) ? 100 : 0);
94 #else
95 	{
96 		unsigned char cent;
97 		i2c_read(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
98 		if( !(data[RTC_HOUR_ADDR] & 0x80) ){
99 			printf( "m41t11 RTC: cann't keep track of years without CEB set\n" );
100 			rel = -1;
101 		}
102 		if( (cent & 0x1) != ((data[RTC_HOUR_ADDR]&0x40)>>7) ){
103 			/*century flip store off new year*/
104 			cent += 1;
105 			i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
106 		}
107 		tmp->tm_year =((int)cent*100)+bcd2bin(data[RTC_YEARS_ADDR]);
108 	}
109 #endif
110 	tmp->tm_wday = bcd2bin (data[RTC_DAY_ADDR]  & 0x07);
111 	tmp->tm_yday = 0;
112 	tmp->tm_isdst= 0;
113 
114 	debug ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
115 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
116 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
117 
118 	return rel;
119 }
120 
121 int rtc_set (struct rtc_time *tmp)
122 {
123 	uchar data[RTC_REG_CNT];
124 
125 	debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
126 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
127 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
128 
129 	data[RTC_SEC_ADDR]    = bin2bcd(tmp->tm_sec) &  0x7F;/*just in case*/
130 	data[RTC_MIN_ADDR]    = bin2bcd(tmp->tm_min);
131 	data[RTC_HOUR_ADDR]   = bin2bcd(tmp->tm_hour) & 0x3F;/*handle cent stuff later*/
132 	data[RTC_DATE_ADDR]   = bin2bcd(tmp->tm_mday) & 0x3F;
133 	data[RTC_MONTH_ADDR]  = bin2bcd(tmp->tm_mon);
134 	data[RTC_DAY_ADDR]    = bin2bcd(tmp->tm_wday) & 0x07;
135 
136 	data[RTC_HOUR_ADDR]   |= 0x80;/*we will always use CEB*/
137 
138 	data[RTC_YEARS_ADDR]  = bin2bcd(tmp->tm_year%100);/*same thing either way*/
139 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
140 	if( ((tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 200) ||
141 	    (tmp->tm_year < CONFIG_SYS_M41T11_BASE_YEAR) ){
142 		printf( "m41t11 RTC setting year out of range!!need recompile\n" );
143 	}
144 	data[RTC_HOUR_ADDR] |= (tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 100 ? 0x40 : 0;
145 #else
146 	{
147 		unsigned char cent;
148 		cent = tmp->tm_year ? tmp->tm_year / 100 : 0;
149 		data[RTC_HOUR_ADDR] |= (cent & 0x1) ? 0x40 : 0;
150 		i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, &cent, M41T11_YEAR_SIZE);
151 	}
152 #endif
153 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
154 
155 	return 0;
156 }
157 
158 void rtc_reset (void)
159 {
160 	unsigned char val;
161 	/* clear all control & status registers */
162 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, 1);
163 	val = val & 0x7F;/*make sure we are running*/
164 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, &val, RTC_REG_CNT);
165 
166 	i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
167 	val = val & 0x3F;/*turn off freq test keep calibration*/
168 	i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_CONTROL_ADDR, 1, &val, 1);
169 }
170 #endif
171