1 // SPDX-License-Identifier: GPL-2.0+
4 * Andrew May, Viasat Inc, amay@viasat.com
8 * M41T11 Serial Access Timekeeper(R) SRAM
9 * can you believe a trademark on that?
20 I Don't have an example config file but this
21 is what should be done.
23 #define CONFIG_RTC_M41T11 1
24 #define CONFIG_SYS_I2C_RTC_ADDR 0x68
26 #define CONFIG_SYS_M41T11_EXT_CENTURY_DATA
28 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
32 /* ------------------------------------------------------------------------- */
34 these are simple defines for the chip local to here so they aren't too
36 DAY/DATE aren't nice but that is how they are on the data sheet
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
48 #define RTC_CONTROL_ADDR 0x7
51 #ifndef CONFIG_SYS_M41T11_EXT_CENTURY_DATA
53 #define REG_CNT (RTC_REG_CNT+1)
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
59 #ifndef CONFIG_SYS_M41T11_BASE_YEAR
60 #define CONFIG_SYS_M41T11_BASE_YEAR 2000
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)
70 #define M41T11_STORAGE_SZ (64-REG_CNT)
72 int rtc_get (struct rtc_time *tmp)
75 uchar data[RTC_REG_CNT];
77 i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
79 if( data[RTC_SEC_ADDR] & 0x80 ){
80 printf( "m41t11 RTC Clock stopped!!!\n" );
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);
95 i2c_read(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, ¢, M41T11_YEAR_SIZE);
96 if( !(data[RTC_HOUR_ADDR] & 0x80) ){
97 printf( "m41t11 RTC: cann't keep track of years without CEB set\n" );
100 if( (cent & 0x1) != ((data[RTC_HOUR_ADDR]&0x40)>>7) ){
101 /*century flip store off new year*/
103 i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T11_YEAR_DATA, 1, ¢, M41T11_YEAR_SIZE);
105 tmp->tm_year =((int)cent*100)+bcd2bin(data[RTC_YEARS_ADDR]);
108 tmp->tm_wday = bcd2bin (data[RTC_DAY_ADDR] & 0x07);
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);
119 int rtc_set (struct rtc_time *tmp)
121 uchar data[RTC_REG_CNT];
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);
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;
134 data[RTC_HOUR_ADDR] |= 0x80;/*we will always use CEB*/
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" );
142 data[RTC_HOUR_ADDR] |= (tmp->tm_year - CONFIG_SYS_M41T11_BASE_YEAR) > 100 ? 0x40 : 0;
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, ¢, M41T11_YEAR_SIZE);
151 i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_SEC_ADDR, 1, data, RTC_REG_CNT);
156 void rtc_reset (void)
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);
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);