Geode integrated peripherals support?

Milan Obuch bsd at dino.sk
Wed Jan 19 01:01:07 PST 2005


On Wednesday 19 January 2005 01:43, John-Mark Gurney wrote:
> Milan Obuch wrote this message on Mon, Jan 17, 2005 at 13:14 +0100:
> > On Monday 17 January 2005 12:55, Bruce M Simpson wrote:
> > > On Sun, Jan 16, 2005 at 03:01:17PM +0100, Milan Obuch wrote:
> > > > ACCESS.bus support (i2c bus compatible) and LPC bus bridge (for
> > > > expansion). The first one is present in OpenBSD. I am currently
> > > > studying that and FreeBSD kernel sources to try port it, however, any
> > > > help would be great. No idea on LPC, through...
> > >
> > > There's some i2c support in FreeBSD already, whether or not this
> > > applies to the i2c hardware in the Geode I don't know. iic(4) would be
> > > a good place to start.
> >
> > I think so. However, I built kernel with device iic, iicbus, iicbb, but
> > nothing shows. As said, I am doing my 'homework' now - astudying sources,
> > but, as usual, any help appreciated.
>
> Well, as having used the i2c code, I know it works...  You probably
> need to look at the hardware spec, and figure out if you need to write
> a iicbb device driver (one that directly controls the SCL/SDA lines), or
> a higher level one, that has hardware that can issue i2c reads and wrights
> directly...
>
> I recently d/l'd the ACCESS.bus spec myself, since I have a firewire/usb2.0
> card that says it's an ACCESS.bus card, but not quite (the subrev is
> wrong for access.bus), and didn't realize that ACCESS.bus was so close
> to i2c..  There might need to be a layer written on top of i2c to make
> it appear as an access.bus and do access.bus type things..

Great, could we cooperate?
I know there are two modes - bit banging software i2c bus and real hardware 
controller. Which one would be easier to begin with? With geode, both are 
possible. Pins designed for ACCESS.bus (at least the second, there are two 
buses integrated) can be used as GPIO pins.
Actually the first thing I need to get working is simple LM75 sensor reading, 
which is just i2c device, so nothing else (higher level access.bus layer) is 
necessary for me.
Regards,
Milan


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