Subject: Re: IBM405GP/GPr OPB bus_space endian (powerpc/ibm4xx/dev/opb.c)
To: Simon Burge <>
From: Jared D. McNeill <>
List: port-powerpc
Date: 10/03/2005 14:43:24
On Tue, 4 Oct 2005, Simon Burge wrote:
> Jared and Quentin (both CC'd here) have some ideas on directly attaching
> the gpio to the opb.  Jared set up the net4801 (i386) so that the gpio
> was directly attached to the PCI-ISA bridge.  I'll let them speak up
> about that.

Well, on the NS Geode GX, you get the GPIO I/O base from reading a PCI 
configuration register on the PCI-ISA bridge. We simply map this region 
from within gscpcib(4), setup the GPIO glue, and call config_found 
(passing in the required gpiobus_attach_args).

I'm not sure how things work in OPB land -- is it possible for opb(4) to 
talk directly to the gpio pins? Or is your (old) gpio@opb a real device 
attached to an opb? If you can pull off the same trick that we use in 
gscpcib(4), you can certainly avoid having an extra device driver involved