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/rk3399_rockchip-uboot/drivers/rtc/
H A Dpcf8563.cdf930e9b3c6a644d1b0b50dce31fc9f4686925c2 Fri Jul 20 14:05:36 UTC 2012 Benoît Thébaudeau <benoit.thebaudeau@advansee.com> rtc: pcf8563: Make century compatible with Linux

This driver uses the century bit of this RTC in the opposite way Linux does.
From Linux's rtc-pcf8563.c:
/*
* The meaning of MO_C bit varies by the chip type.
* From PCF8563 datasheet: this bit is toggled when the years
* register overflows from 99 to 00
* 0 indicates the century is 20xx
* 1 indicates the century is 19xx
* From RTC8564 datasheet: this bit indicates change of
* century. When the year digit data overflows from 99 to 00,
* this bit is set. By presetting it to 0 while still in the
* 20th century, it will be set in year 2000, ...
* There seems no reliable way to know how the system use this
* bit. So let's do it heuristically, assuming we are live in
* 1970...2069.
*/

As U-Boot's PCF8563 driver does not say it is supposed to support the RTC8564,
make this driver compatible with Linux's by giving the opposite meaning to the
century bit.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>