Re: [PATCH] powerpc: consolidate mpc83xx platform files

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Tue, 2006-12-12 at 16:41 -0600, Scott Wood wrote:
> Kumar Gala wrote:
> > On Dec 12, 2006, at 3:30 PM, Scott Wood wrote:
> >> They *may* not want to (and they certainly shouldn't be forced to),  but
> >> some may not want to define a new ppc_md (or modify a probe function)
> >> for every new board if all of the differences are encapsulated in the
> >> device tree.  I thought one of the main goals of having a device  tree is
> >> that if it's done right, the kernel need not know about every single
> >> model of board, just the different components that a device tree can
> >> specify.
> > 
> > That's true, and if that's the case you'd just set your "model" to  
> > match an existing supported ppc_md.
> 
> Having an 831x explicitly claim to be an 834x is just a tad icky...

Indeed, but "compatible" doesn't mean exact match and can be a list. In
fact, it should probably be the other way around, that is 834x claim to
be compatible with 831x... something like:

 "834x\0831x\083xx" (with appropriate board name appended of course).

> And an 83xx-generic machine description does not stop them from doing 
> so.  "Generic" does not mean "universal".  It means "there's nothing 
> special about this board".  If you need board-specific code in the 
> kernel, then don't label it generic.

As long as you are careful enough so that your "generic" ppc_md. doesn't
try to match everything with a 83xx in it :-0

Ben.