Re: [PATCH v2 3/3] drivers: cleanup Kconfig stuff

[Roger Quadros]

On 10/20/2010 12:23 PM, ext Felipe Contreras wrote:
> On Wed, Oct 20, 2010 at 12:14 PM, Roger Quadros<roger.quadros@xxxxxxxxx>  wrote:
> > On 10/20/2010 11:53 AM, ext felipe.contreras@xxxxxxxxx wrote:
> > > On Wed, Oct 20, 2010 at 10:46 AM, Roger Quadros<roger.quadros@xxxxxxxxx>
> > >   wrote:
> > > > On 10/19/2010 05:33 PM, ext Felipe Contreras wrote:
> > > > > On Tue, Oct 19, 2010 at 4:40 PM, Roger Quadros<roger.quadros@xxxxxxxxx>
> > > > >   wrote:
> > > > > > > @@ -843,6 +841,7 @@ config USB_CDC_COMPOSITE
> > > > > > >   config USB_G_NOKIA
> > > > > > >         tristate "Nokia composite gadget"
> > > > > > >         depends on PHONET
> > > > > > > +       depends on USB_GADGET_MUSB_HDRC
> > > > > >
> > > > > > This is wrong. Is there a build problem or run-time problem without
> > > > > > this?
> > > > >
> > > > > Try:
> > > > > CONFIG_USB_G_NOKIA=y
> > > > > CONFIG_USB_GADGET_MUSB_HDRC=n
> > > > >
> > > > > At least g_nokia doesn't seem to work correctly on my N900.
> > > > It won't work on N900 because N900 has MUSB USB gadget controller and it
> > > > needs to be selected somehow while building for N900.
> > > >
> > > > You should set CONFIG_USB_GADGET_MUSB_HDRC to y somewhere else while
> > > > building for N900 and not here because g_nokia is not MUSB specific.
> > >
> > > How do you expect people to know that? The Kconfig should define what
> > > USB_G_NOKIA needs to work, so that people can enable those things
> > > without go Googling hunting for a workable defconfig. Right now people
> > > can build g_nokia modules that don't work, and that shouldn't be
> > > allowed by the Kconfig.
> >
> > USB_G_NOKIA just needs a USB gadget controller to work. The gadget
> > controller used for the board should come from the board's Kconfig which
> > will ideally be supplied by the board's vendor.
>
> Ok, but USB_OMAP is not supposed to work on the N900? (I tried and it didn't)

No it won't work. USB_OMAP was for older OMAP's. MUSB is on OMAP3 and later. But 
MUSB is not limited to OMAP SoC.

> > For example, can't USB_GADGET_MUSB_HDRC be selected in MACH_NOKIA_RX51 in
> > arch/arm/mach-omap2/Kconfig? or is there a better place to put it?
>
> I don't think so, because people might not want USB at all. The ideal
> case would be for USB_GADGET_MUSB_HDRC to be selected automatically
> when the user selects USB and USB_GADGET, but that's not happening
> because USB_GADGET_OMAP is selected first (all the dependencies are
> met).
Yes you are right. In think with the current setup (i.e. controller selection at 
kconfig and limitation to one controller per config) we will never be able to 
satisfy all users.

We might need to move to some kind of gadget controller framework and runtime 
controller selection to solve this problem.

--
regards,
-roger
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