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

On Wed, 24 Oct 2012, Mitch Bradley wrote:

quoted

quoted

Ah, now I'm starting to get the picture.

So by listing "usb-ehci" in its device ID table, a driver would
essentially be saying that it can handle _all_ USB EHCI controllers.  

Actually, it means that the driver can handle at least USB EHCI
controllers that are 100% compatible with the EHCI spec (requiring
nothing extra).  The driver might be able to handle almost-compatible
controllers, possibly with the help of additional properties.

Unfortunately that's not saying very much.  The EHCI spec describes
only PCI-based controllers.  Every other sort does require something
extra.

If a DT node lists "usb-ehci" as a "fallback", it's not guaranteed that
a given version of that driver will work, but it's worth a try in the
event that no more-specific driver is matched.

While I haven't checked in detail, it seems quite likely that this 
would not work with some of the devices that have "usb-ehci" listed in 
their compatible values.

Alan Stern

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