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>
Modify the RTC API to provide one a status for the time reported by
the rtc_get() function:
0 - a reliable time is guaranteed,
< 0 - a reliable time isn't guaranteed (power fault, clock issues,
and so on).
The RTC chip drivers are responsible for providing this info if the
corresponding chip supports such functionality. If not - always
report that the time is reliable.
The POST RTC test was modified to detect the RTC faults utilizing
this new rtc_get() feature.
Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
