[PATCH v2 2/2] USB: doc: Binding document for ehci-platform driver

Florian Fainelli florian at openwrt.org
Wed Oct 24 14:18:12 EDT 2012

On Wednesday 24 October 2012 14:04:12 Alan Stern wrote:
> On Wed, 24 Oct 2012, Florian Fainelli wrote:
> > As long as no one enables both ehci-platform and ehci-ppc-of at the same time
> > there is no problem. ehci-ppc-of should be removed in favor of ehci-platform
> > and make sure that the specific quirk in ehci-ppc-of also gets ported, other 
> > that I see no issue using "usb-ehci" as the least detailed compatible property
> > name.
> Suppose a DT board file is created for a oontroller which ehci-platform
> can't handle.  Then by your proposal, the board file shouldn't have
> "usb-ehci" in its compatible property.
> Now later on, suppose ehci-platform is enhanced so that it can manage
> that controller.  It's too late to update the board file because the
> information has already been written to various firmwares.  The
> enhanced ehci-platform would have to include a special entry to match
> the controller.

In any case you are supposed to use a compatible property which describes
as much as possible your hardware, and this one should have the precedence
if a special treatment is required, so I see no problem with this approach.

> Since this reasoning applies every time ehci-platform is updated, it 
> seems reasonable to use the same approach right from the beginning.
> Alan Stern

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