[PATCH] Add of_platform_device_scan().
scottwood at freescale.com
Thu Oct 5 05:33:38 EST 2006
Arnd Bergmann wrote:
> On Wednesday 04 October 2006 18:32, Scott Wood wrote:
>>What I'd really like (long-term, of course) is if platform_device and
>>of_device were merged, with device tree support (or at least a means of
>>passing on properties that *could* come from a device tree without
>>special glue code that knows about each property) in arch-neutral code;
>>the mechanism for discovering devices ideally shouldn't depend on the
>>CPU's instruction set.
> My guess is that this won't happen, because other architectures
> normally don't describe their platform devices in a way that is
> anywhere near what we have on powerpc.
They wouldn't need to, unless they want to support a driver that
requires it. It would simply be an architecture-neutral mechanism for
attaching a dynamic list of properties and OF-compatible matching
criteria (or more generally the ability to match on any set of dynamic
properties) to platform devices; the source of the platform data could
choose to use it to represent an OF device tree, to supply a few
properties needed by a specific driver, or not at all.
Ideally, users of static structure-based platform data would gradually
migrate to dynamic properties, but there's a benefit to the integration
even if they don't. The main issue that I forsee being a problem is
clashing with another standard for the naming and content of properties.
There could be tagging to indicate which standard is being followed by
a given property, but that could lead to some ugliness in drivers that
need to support more than one if the differences can't be easily
abstracted by get-me-this-piece-of-information accessor functions (or by
code that generically converts properties from one standard to
another, which is similar to what we've already got in fsl_soc.c, but
hopefully less device-specific).
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