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git.ipfire.org Git - people/ms/u-boot.git/blob - drivers/rtc/m41t60.c
3 * Larry Johnson, lrj@acm.org
5 * based on rtc/m41t11.c which is ...
8 * Andrew May, Viasat Inc, amay@viasat.com
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of
13 * the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 * STMicroelectronics M41T60 serial access real-time clock
37 #if defined(CONFIG_SYS_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE)
39 static unsigned bcd2bin(uchar n
)
41 return ((((n
>> 4) & 0x0F) * 10) + (n
& 0x0F));
44 static unsigned char bin2bcd(unsigned int n
)
46 return (((n
/ 10) << 4) | (n
% 10));
50 * Convert between century and "century bits" (CB1 and CB0). These routines
51 * assume years are in the range 1900 - 2299.
54 static unsigned char year2cb(unsigned const year
)
56 if (year
< 1900 || year
>= 2300)
57 printf("M41T60 RTC: year %d out of range\n", year
);
59 return (year
/ 100) & 0x3;
62 static unsigned cb2year(unsigned const cb
)
64 return 1900 + 100 * ((cb
+ 1) & 0x3);
68 * These are simple defines for the chip local to here so they aren't too
69 * verbose. DAY/DATE aren't nice but that is how they are on the data sheet.
84 static void rtc_dump(char const *const label
)
88 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR
, 0, 1, data
, sizeof(data
))) {
89 printf("I2C read failed in rtc_dump()\n");
92 printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n",
93 label
, data
[0], data
[1], data
[2], data
[3],
94 data
[4], data
[5], data
[6], data
[7]);
97 #define rtc_dump(label)
100 static uchar
*rtc_validate(void)
103 * This routine uses the OUT bit and the validity of the time values to
104 * determine whether there has been an initial power-up since the last
105 * time the routine was run. It assumes that the OUT bit is not being
106 * used for any other purpose.
108 static const uchar daysInMonth
[0x13] = {
109 0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31,
110 0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
113 static uchar data
[8];
114 uchar min
, date
, month
, years
;
116 rtc_dump("begin validate");
117 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR
, 0, 1, data
, sizeof(data
))) {
118 printf("I2C read failed in rtc_validate()\n");
122 * If the OUT bit is "1", there has been a loss of power, so stop the
123 * oscillator so it can be "kick-started" as per data sheet.
125 if (0x00 != (data
[RTC_CTRL
] & 0x80)) {
126 printf("M41T60 RTC clock lost power.\n");
127 data
[RTC_SEC
] = 0x80;
128 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR
, RTC_SEC
, 1, data
, 1)) {
129 printf("I2C write failed in rtc_validate()\n");
134 * If the oscillator is stopped or the date is invalid, then reset the
135 * OUT bit to "0", reset the date registers, and start the oscillator.
137 min
= data
[RTC_MIN
] & 0x7F;
138 date
= data
[RTC_DATE
];
139 month
= data
[RTC_MONTH
] & 0x3F;
140 years
= data
[RTC_YEAR
];
141 if (0x59 < data
[RTC_SEC
] || 0x09 < (data
[RTC_SEC
] & 0x0F) ||
142 0x59 < min
|| 0x09 < (min
& 0x0F) ||
143 0x23 < data
[RTC_HOUR
] || 0x09 < (data
[RTC_HOUR
] & 0x0F) ||
144 0x07 < data
[RTC_DAY
] || 0x00 == data
[RTC_DAY
] ||
146 0x99 < years
|| 0x09 < (years
& 0x0F) ||
147 daysInMonth
[month
] < date
|| 0x09 < (date
& 0x0F) || 0x00 == date
||
148 (0x29 == date
&& 0x02 == month
&&
149 ((0x00 != (years
& 0x03)) ||
150 (0x00 == years
&& 0x00 != (data
[RTC_MONTH
] & 0xC0))))) {
151 printf("Resetting M41T60 RTC clock.\n");
153 * Set to 00:00:00 1900-01-01 (Monday)
155 data
[RTC_SEC
] = 0x00;
156 data
[RTC_MIN
] &= 0x80; /* preserve OFIE bit */
157 data
[RTC_HOUR
] = 0x00;
158 data
[RTC_DAY
] = 0x02;
159 data
[RTC_DATE
] = 0x01;
160 data
[RTC_MONTH
] = 0xC1;
161 data
[RTC_YEAR
] = 0x00;
162 data
[RTC_CTRL
] &= 0x7F; /* reset OUT bit */
164 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR
, 0, 1, data
, sizeof(data
))) {
165 printf("I2C write failed in rtc_validate()\n");
172 int rtc_get(struct rtc_time
*tmp
)
174 uchar
const *const data
= rtc_validate();
179 tmp
->tm_sec
= bcd2bin(data
[RTC_SEC
] & 0x7F);
180 tmp
->tm_min
= bcd2bin(data
[RTC_MIN
] & 0x7F);
181 tmp
->tm_hour
= bcd2bin(data
[RTC_HOUR
] & 0x3F);
182 tmp
->tm_mday
= bcd2bin(data
[RTC_DATE
] & 0x3F);
183 tmp
->tm_mon
= bcd2bin(data
[RTC_MONTH
] & 0x1F);
184 tmp
->tm_year
= cb2year(data
[RTC_MONTH
] >> 6) + bcd2bin(data
[RTC_YEAR
]);
185 tmp
->tm_wday
= bcd2bin(data
[RTC_DAY
] & 0x07) - 1;
189 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
190 tmp
->tm_year
, tmp
->tm_mon
, tmp
->tm_mday
, tmp
->tm_wday
,
191 tmp
->tm_hour
, tmp
->tm_min
, tmp
->tm_sec
);
196 int rtc_set(struct rtc_time
*tmp
)
198 uchar
*const data
= rtc_validate();
203 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
204 tmp
->tm_year
, tmp
->tm_mon
, tmp
->tm_mday
, tmp
->tm_wday
,
205 tmp
->tm_hour
, tmp
->tm_min
, tmp
->tm_sec
);
207 data
[RTC_SEC
] = (data
[RTC_SEC
] & 0x80) | (bin2bcd(tmp
->tm_sec
) & 0x7F);
208 data
[RTC_MIN
] = (data
[RTC_MIN
] & 0X80) | (bin2bcd(tmp
->tm_min
) & 0X7F);
209 data
[RTC_HOUR
] = bin2bcd(tmp
->tm_hour
) & 0x3F;
210 data
[RTC_DATE
] = bin2bcd(tmp
->tm_mday
) & 0x3F;
211 data
[RTC_MONTH
] = bin2bcd(tmp
->tm_mon
) & 0x1F;
212 data
[RTC_YEAR
] = bin2bcd(tmp
->tm_year
% 100);
213 data
[RTC_MONTH
] |= year2cb(tmp
->tm_year
) << 6;
214 data
[RTC_DAY
] = bin2bcd(tmp
->tm_wday
+ 1) & 0x07;
215 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR
, 0, 1, data
, RTC_REG_CNT
)) {
216 printf("I2C write failed in rtc_set()\n");
225 uchar
*const data
= rtc_validate();
226 char const *const s
= getenv("rtccal");
231 rtc_dump("begin reset");
233 * If environmental variable "rtccal" is present, it must be a hex value
234 * between 0x00 and 0x3F, inclusive. The five least-significan bits
235 * represent the calibration magnitude, and the sixth bit the sign bit.
236 * If these do not match the contents of the hardware register, that
237 * register is updated. The value 0x00 imples no correction. Consult
238 * the M41T60 documentation for further details.
241 unsigned long const l
= simple_strtoul(s
, 0, 16);
244 if ((data
[RTC_CTRL
] & 0x3F) != l
) {
245 printf("Setting RTC calibration to 0x%02lX\n",
247 data
[RTC_CTRL
] &= 0xC0;
248 data
[RTC_CTRL
] |= (uchar
) l
;
251 printf("environment parameter \"rtccal\" not valid: "
255 * Turn off frequency test.
257 data
[RTC_CTRL
] &= 0xBF;
258 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR
, RTC_CTRL
, 1, data
+ RTC_CTRL
, 1)) {
259 printf("I2C write failed in rtc_reset()\n");
262 rtc_dump("end reset");
264 #endif /* CONFIG_RTC_M41T60 && CONFIG_SYS_I2C_RTC_ADDR && CONFIG_CMD_DATE */