[PATCH 9/13] powerpc: Add arch/powerpc mv64x60 I2C platform data setup

[Dale Farnsworth]

On Thu, Apr 26, 2007 at 11:00:25AM +0200, Arnd Bergmann wrote:
> On Thursday 26 April 2007, Dale Farnsworth wrote:
> > 
> > > Ok, I see your point there. But after looking at the i2c and net drivers,
> > > I believe that they can easily be split into an architecture dependent
> > > part that is either an of_platform_driver or a platform_driver, and
> > > a common part that does not know about either of these.
> > 
> > Oh, it's certainly possible, but it doesn't seem desirable to me. Why
> > should the drivers carry the burden of supporting both platform_driver
> > and of_platform_driver interfaces?
> 
> The reason is that platform_devices are for stuff that fundamentally cannot
> be probed but has to be hardcoded in some place.
> 
> The point about the of device tree is that it allows you to probe this
> kind of device. This means you get automatic module loading based on the
> device tree, and that the devices show up in sane locations in /sys.

I understand the benefits of the DT; that's not the issue.

Here we have platform devices common to MIPS and PowerPC platforms.
The drivers must continue to support the platform_driver interface
for MIPS platforms.  The question is, where should we put the glue
that transforms the DT info into the platform_driver format?

You seem to suggest putting the ethernet-related glue into
drivers/net/mv643xx_eth.c.  That's bogus, IMHO. The base driver
shouldn't have to accommodate every arch-specific interface.
(I know OF isn't strictly arch-specific, but it's far from universal.)
I put this glue into arch/powerpc/sysdev/mv64x60.c. I still don't see
the benefit of moving it into the drivers.

-Dale