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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 * SPDX-License-Identifier: GPL-2.0+
14 * STMicroelectronics M41T60 serial access real-time clock
24 #if defined(CONFIG_SYS_I2C_RTC_ADDR) && defined(CONFIG_CMD_DATE)
27 * Convert between century and "century bits" (CB1 and CB0). These routines
28 * assume years are in the range 1900 - 2299.
31 static unsigned char year2cb(unsigned const year
)
33 if (year
< 1900 || year
>= 2300)
34 printf("M41T60 RTC: year %d out of range\n", year
);
36 return (year
/ 100) & 0x3;
39 static unsigned cb2year(unsigned const cb
)
41 return 1900 + 100 * ((cb
+ 1) & 0x3);
45 * These are simple defines for the chip local to here so they aren't too
46 * verbose. DAY/DATE aren't nice but that is how they are on the data sheet.
61 static void rtc_dump(char const *const label
)
65 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR
, 0, 1, data
, sizeof(data
))) {
66 printf("I2C read failed in rtc_dump()\n");
69 printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n",
70 label
, data
[0], data
[1], data
[2], data
[3],
71 data
[4], data
[5], data
[6], data
[7]);
74 #define rtc_dump(label)
77 static uchar
*rtc_validate(void)
80 * This routine uses the OUT bit and the validity of the time values to
81 * determine whether there has been an initial power-up since the last
82 * time the routine was run. It assumes that the OUT bit is not being
83 * used for any other purpose.
85 static const uchar daysInMonth
[0x13] = {
86 0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31,
87 0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
91 uchar min
, date
, month
, years
;
93 rtc_dump("begin validate");
94 if (i2c_read(CONFIG_SYS_I2C_RTC_ADDR
, 0, 1, data
, sizeof(data
))) {
95 printf("I2C read failed in rtc_validate()\n");
99 * If the OUT bit is "1", there has been a loss of power, so stop the
100 * oscillator so it can be "kick-started" as per data sheet.
102 if (0x00 != (data
[RTC_CTRL
] & 0x80)) {
103 printf("M41T60 RTC clock lost power.\n");
104 data
[RTC_SEC
] = 0x80;
105 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR
, RTC_SEC
, 1, data
, 1)) {
106 printf("I2C write failed in rtc_validate()\n");
111 * If the oscillator is stopped or the date is invalid, then reset the
112 * OUT bit to "0", reset the date registers, and start the oscillator.
114 min
= data
[RTC_MIN
] & 0x7F;
115 date
= data
[RTC_DATE
];
116 month
= data
[RTC_MONTH
] & 0x3F;
117 years
= data
[RTC_YEAR
];
118 if (0x59 < data
[RTC_SEC
] || 0x09 < (data
[RTC_SEC
] & 0x0F) ||
119 0x59 < min
|| 0x09 < (min
& 0x0F) ||
120 0x23 < data
[RTC_HOUR
] || 0x09 < (data
[RTC_HOUR
] & 0x0F) ||
121 0x07 < data
[RTC_DAY
] || 0x00 == data
[RTC_DAY
] ||
123 0x99 < years
|| 0x09 < (years
& 0x0F) ||
124 daysInMonth
[month
] < date
|| 0x09 < (date
& 0x0F) || 0x00 == date
||
125 (0x29 == date
&& 0x02 == month
&&
126 ((0x00 != (years
& 0x03)) ||
127 (0x00 == years
&& 0x00 != (data
[RTC_MONTH
] & 0xC0))))) {
128 printf("Resetting M41T60 RTC clock.\n");
130 * Set to 00:00:00 1900-01-01 (Monday)
132 data
[RTC_SEC
] = 0x00;
133 data
[RTC_MIN
] &= 0x80; /* preserve OFIE bit */
134 data
[RTC_HOUR
] = 0x00;
135 data
[RTC_DAY
] = 0x02;
136 data
[RTC_DATE
] = 0x01;
137 data
[RTC_MONTH
] = 0xC1;
138 data
[RTC_YEAR
] = 0x00;
139 data
[RTC_CTRL
] &= 0x7F; /* reset OUT bit */
141 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR
, 0, 1, data
, sizeof(data
))) {
142 printf("I2C write failed in rtc_validate()\n");
149 int rtc_get(struct rtc_time
*tmp
)
151 uchar
const *const data
= rtc_validate();
156 tmp
->tm_sec
= bcd2bin(data
[RTC_SEC
] & 0x7F);
157 tmp
->tm_min
= bcd2bin(data
[RTC_MIN
] & 0x7F);
158 tmp
->tm_hour
= bcd2bin(data
[RTC_HOUR
] & 0x3F);
159 tmp
->tm_mday
= bcd2bin(data
[RTC_DATE
] & 0x3F);
160 tmp
->tm_mon
= bcd2bin(data
[RTC_MONTH
] & 0x1F);
161 tmp
->tm_year
= cb2year(data
[RTC_MONTH
] >> 6) + bcd2bin(data
[RTC_YEAR
]);
162 tmp
->tm_wday
= bcd2bin(data
[RTC_DAY
] & 0x07) - 1;
166 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
167 tmp
->tm_year
, tmp
->tm_mon
, tmp
->tm_mday
, tmp
->tm_wday
,
168 tmp
->tm_hour
, tmp
->tm_min
, tmp
->tm_sec
);
173 int rtc_set(struct rtc_time
*tmp
)
175 uchar
*const data
= rtc_validate();
180 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
181 tmp
->tm_year
, tmp
->tm_mon
, tmp
->tm_mday
, tmp
->tm_wday
,
182 tmp
->tm_hour
, tmp
->tm_min
, tmp
->tm_sec
);
184 data
[RTC_SEC
] = (data
[RTC_SEC
] & 0x80) | (bin2bcd(tmp
->tm_sec
) & 0x7F);
185 data
[RTC_MIN
] = (data
[RTC_MIN
] & 0X80) | (bin2bcd(tmp
->tm_min
) & 0X7F);
186 data
[RTC_HOUR
] = bin2bcd(tmp
->tm_hour
) & 0x3F;
187 data
[RTC_DATE
] = bin2bcd(tmp
->tm_mday
) & 0x3F;
188 data
[RTC_MONTH
] = bin2bcd(tmp
->tm_mon
) & 0x1F;
189 data
[RTC_YEAR
] = bin2bcd(tmp
->tm_year
% 100);
190 data
[RTC_MONTH
] |= year2cb(tmp
->tm_year
) << 6;
191 data
[RTC_DAY
] = bin2bcd(tmp
->tm_wday
+ 1) & 0x07;
192 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR
, 0, 1, data
, RTC_REG_CNT
)) {
193 printf("I2C write failed in rtc_set()\n");
202 uchar
*const data
= rtc_validate();
203 char const *const s
= env_get("rtccal");
208 rtc_dump("begin reset");
210 * If environmental variable "rtccal" is present, it must be a hex value
211 * between 0x00 and 0x3F, inclusive. The five least-significan bits
212 * represent the calibration magnitude, and the sixth bit the sign bit.
213 * If these do not match the contents of the hardware register, that
214 * register is updated. The value 0x00 imples no correction. Consult
215 * the M41T60 documentation for further details.
218 unsigned long const l
= simple_strtoul(s
, 0, 16);
221 if ((data
[RTC_CTRL
] & 0x3F) != l
) {
222 printf("Setting RTC calibration to 0x%02lX\n",
224 data
[RTC_CTRL
] &= 0xC0;
225 data
[RTC_CTRL
] |= (uchar
) l
;
228 printf("environment parameter \"rtccal\" not valid: "
232 * Turn off frequency test.
234 data
[RTC_CTRL
] &= 0xBF;
235 if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR
, RTC_CTRL
, 1, data
+ RTC_CTRL
, 1)) {
236 printf("I2C write failed in rtc_reset()\n");
239 rtc_dump("end reset");
241 #endif /* CONFIG_RTC_M41T60 && CONFIG_SYS_I2C_RTC_ADDR && CONFIG_CMD_DATE */