[LinuxBIOS] RTC on geode gx1

Peter Stuge stuge-linuxbios at cdy.org
Wed Mar 30 21:41:58 CEST 2005

On Tue, Mar 29, 2005 at 07:28:00PM -0800, ramesh bios wrote:
> I'm using the freebios v1 tree on a geode
> gx1/cs5530a/w83977 with 2.6.11. I noticed that there
> appears to be problem with writing to the RTC using
> hwclock. I seem to be able to use hwclock to set the
> time but not the date. That is:

There are a few bits in the 5530 at page 107 in the data sheet
regarding the RTC, but I doubt the RTC would be reachable at all if
they weren't ok.

I just went over the RTC part of the W83977F data sheet too and it
seems to have a couple of control bits that may have to be tweaked
to get proper operation. I don't remember if anyone else has had
similar problems with that superio.

Besides timing, the only other explanation I can think of is that
since time is stored in RTC registers 00h, 02h and 04h, date of month
in 07h and month/year in 08h-09h, if address bit 3 wasn't connected
properly then the date registers would be unreachable, but then you
should see some connection between time and date, so lack of proper
initialization or possibly a timing issue is my guess..


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