[RFC] Rework of i2c-mpc.c - Freescale i2c driver

[Grant Likely]

On 11/5/07, Scott Wood <scottwood at freescale.com> wrote:
> Jon Smirl wrote:
> > On 11/5/07, Scott Wood <scottwood at freescale.com> wrote:
> >> Jon Smirl wrote:
> >>> This is my first pass at reworking the Freescale i2c driver. It
> >>> switches the driver from being a platform driver to an open firmware
> >>> one. I've checked it out on my hardware and it is working.
> >> We may want to hold off on this until arch/ppc goes away (or at least
> >> all users of this driver in arch/ppc).
> >
> > How about renaming the old driver file and leaving it hooked to ppc?
> > Then it would get deleted when ppc goes away. That would let work
> > progress on the powerpc version.
>
> Or we could have one driver that has two probe methods.  I don't like
> forking the driver.

I agree.  This driver can and should have multiple bus bindings.

> >>>       cell-index = <1>;
> >> What is cell-index for?
> >
> > I was using it to control the bus number, is that the wrong attribute?
>
> It shouldn't be specified at all -- the hardware has no concept of a
> device number.

cell-index is important.  It describes the hardware, or more
specifically the layout of the SoC.  The SoC has 2 i2c busses which
are numbered 0 and 1.  This property should stay for the 5200.
However, that is the only purpose of it.  cell-index does *not*
describe the system level bus number.

> > I was allowing control of the bus number with "cell-index" and
> > i2c_add_numbered_adapter().
> > Should I get rid of this and switch to i2c_add_adapter()?
>
> Yes.

Yes, the purpose of cell-index is not to give an i2c bus number enumeration.

Cheers,
g.

-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
grant.likely at secretlab.ca
(403) 399-0195