10  * SPDX-License-Identifier:	GPL-2.0+
14  * STMicroelectronics M41T60 serial access real-time clock
28  * assume years are in the range 1900 - 2299.
31 static unsigned char year2cb(unsigned const year)  in year2cb()  argument
33 	if (year < 1900 || year >= 2300)  in year2cb()
34 		printf("M41T60 RTC: year %d out of range\n", year);  in year2cb()
36 	return (year / 100) & 0x3;  in year2cb()
69 	printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n",  in rtc_dump()
81 	 * determine whether there has been an initial power-up since the last  in rtc_validate()
100 	 * oscillator so it can be "kick-started" as per data sheet.  in rtc_validate()
112 	 * OUT bit to "0", reset the date registers, and start the oscillator.  in rtc_validate()
130 		 * Set to 00:00:00 1900-01-01 (Monday)  in rtc_validate()
154 		return -1;  in rtc_get()
156 	tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F);  in rtc_get()
157 	tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F);  in rtc_get()
158 	tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F);  in rtc_get()
159 	tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F);  in rtc_get()
160 	tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F);  in rtc_get()
161 	tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]);  in rtc_get()
162 	tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1;  in rtc_get()
163 	tmp->tm_yday = 0;  in rtc_get()
164 	tmp->tm_isdst = 0;  in rtc_get()
166 	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",  in rtc_get()
167 	      tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,  in rtc_get()
168 	      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);  in rtc_get()
178 		return -1;  in rtc_set()
180 	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",  in rtc_set()
181 	      tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,  in rtc_set()
182 	      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);  in rtc_set()
184 	data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F);  in rtc_set()
185 	data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F);  in rtc_set()
186 	data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F;  in rtc_set()
187 	data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F;  in rtc_set()
188 	data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F;  in rtc_set()
189 	data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100);  in rtc_set()
190 	data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6;  in rtc_set()
191 	data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07;  in rtc_set()
194 		return -1;  in rtc_set()
211 	 * between 0x00 and 0x3F, inclusive.  The five least-significan bits  in rtc_reset()