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From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: [PATCH] powerpc: Create "rom" (MTD) device prpmc2800
Date: Sun, 3 Jun 2007 19:45:17 +0200
To: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: ppcdev <linuxppc-dev@ozlabs.org>, Milton Miller <miltonm@bga.com>
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>> I think "direct-mapped" as compatible is a bit too broad or vague.
>
>     It's actually not -- it means simple 1:1 address mapping (w/o 
> explicit
> byte-swapping and such).

Which has nothing to do with "compatible"; instead,
it is implied by the parent node have a "ranges"
property.  Or you can put some other property in
the flash node for all I care, if that seems
necessary for certain cases.

>> The compatible is supposed to be useable to find and match a driver
>> without regard to the name of the node.  Perhaps direct-mapped-rom?
>> (as opossed to a direct-mapped-ram, sram, or some width flash bank).
>
>     Note that we're matching by both "device_type" and "compatible".

Which is wrong.

>     This would serve no purpose, as the driver that would catches all 
> these is
> signle one, drivers/mtd/maps/physmap_of.c...

With the current kernel version, perhaps.  Did you check
out 2.6.28?  Does it work with that?


Segher