Geode SC1100 i2c bus

[perryh at pluto.rain.com]

> > The ACB is at the same level than Uart, so I had a look at sio
> > source and got a big headache. I'm not really used to drivers
> > nor kernel programming stuff, that's why I need your help.
>
> Why do you compare ACB and UART? In FreeBSD, sio is serial i/o
> controller, not superIO, maybe you are confused... ACB and UART
> does not have much in common...

As I read the OP, both the ACB and the serial are in the same chip
(the superIO), so it would seem reasonable to expect that the method
of accessing the device registers in the (currently unsupported) ACB
might be similar to the method of accessing the device registers in
the (supported) serial port.

Note I said "reasonable" -- it may not be "accurate" -- and
this sort of analysis applies only to getting at the hardware.
Certainly the means of communicating with the rest of the OS
would be different, unless one wants the ACB to show up as sio7
or some such :)