Messages in this thread | | | Date | Tue, 22 Jan 2013 10:19:06 -0500 (EST) | From | Alan Stern <> | Subject | Re: [PATCH 13/15] USB: ehci: make orion and mxc bus glues coexist |
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On Tue, 22 Jan 2013, Manjunath Goudar wrote:
> > > I think we can actually > > > get the same results by turning the Kconfig logic around and making > > > the platform glue drivers 'select USB_EHCI_HCD' than depending on > > > it. > > > > That's a good idea. The Kconfig changes would have to be done > > carefully to make sure that the dependency on USB_ARCH_HAS_EHCI still > > applies to all the platform drivers. > > > > Manjunath, would you like to send a patch to do this? > > > > Alan Stern > > > > Ya sure,could you explain little bit briefly about the Kconfig changes.
Suppose you do exactly what Arnd proposed: add "select USB_EHCI_HCD" to the Kconfig entries for each of the platform glue drivers. Then consider what would happen in a build where USB_ARCH_HAS_EHCI is "n" but one of those glue drivers is enabled. There would be conflicting requirements on USB_EHCI_HCD: The new "select" would force it to be on, but the existing "depends on USB && USB_ARCH_HAS_EHCI" would force it to be off. The build would fail.
In order to prevent this, you have to make sure that each glue driver depends on USB_ARCH_HAS_EHCI. A simple way to do this is to surround the Kconfig entries for those drivers with "if USB && USB_ARCH_HAS_EHCI" ... "endif".
Come to think of it, the "if USB" part really should protect the entire file.
Alan Stern
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