[U-Boot] RTC value corruption on QIL-A9G20 startup

[Stephen Caudle <stephen@doceme.com>]

Hello Albin,

I tried using your patches for the TNY-A9G20 on my QIL-A9G20 board from
Calao.  Everything seems to work properly except the RTC.  They use the same
M41T94 part and the CS is the same on both boards (PA3).  I can set the RTC
using the "date" command and read back the value okay.  However, when I
power cycle the board, the value is getting corrupted at startup due to some
erroneous SPI write.

I don't believe the code you submitted is causing this problem because the
RTC is getting corrupted even if I compile out SPI and RTC support
completely.  I was just wondering if you have seen this problem on your
board?  I probed the CS line with an oscilloscope and I am definitely seeing
it go low on U-Boot startup for a short time, but the clock line seems to be
floating.  I believe the activation of the CS at startup is causing junk
data to be written to the RTC, which is corrupting it.  Any idea why this
might be happenning?

Regards,
Stephen