Re: [PATCH 4/4 v2] [RFC] UIO: generic platform driver

From: Russell King - ARM Linux
Date: Sat Apr 12 2008 - 09:17:27 EST


On Fri, Apr 11, 2008 at 01:25:43PM +0200, Uwe Kleine-König wrote:
> Hello,
>
> [Added Russell King to Cc:]
>
> Hans J. Koch wrote:
> > On Fri, Apr 11, 2008 at 01:03:58PM +0200, Uwe Kleine-König wrote:
> > > Hello,
> > >
> > > Hans J. Koch wrote:
> > > > On Fri, Apr 11, 2008 at 11:21:58AM +0200, Uwe Kleine-König wrote:
> > > > >
> > > > > Below is a new version that uses linux/stringify and zeros size for
> > > > > unused mappings (line 102ff).
> > > >
> > > > Thanks, but it doesn't compile, neither with -rc8 nor with Linus' git.
> > > >
> > > > One problem can easily be fixed, the macro is called __stringify, not
> > > > stringify.
> > > I just notice that, too. My mail address that and your's just crossed
> > > each other.
> > >
> > > > But what about this:
> > > >
> > > > ERROR: "clk_get" [drivers/uio/uio_pdrv.ko] undefined!
> > > > ERROR: "clk_enable" [drivers/uio/uio_pdrv.ko] undefined!
> > > > ERROR: "clk_disable" [drivers/uio/uio_pdrv.ko] undefined!
> > > > ERROR: "clk_put" [drivers/uio/uio_pdrv.ko] undefined!
> > > >
> > > > Do you have any extra patches applied?
> > > Yes I have, but nothing special. This is part of a generic API defined
> > > in include/linux/clk.h. One of it's use it to abstract away some
> > > platform dependencies. There are several architectures that define
> > > it[1].
> >
> > I know. Unfortunately, I tested on x86_64, and it doesn't compile.
> > If it's depending on something, then this dependency should be added in
> > Kconfig. If it can be selected in the configuration, I expect it to
> > compile (and work).
> Maybe adding a dummy implementation that is compiled for machines that
> don't provide a native one. Currently there is no cpp symbol that tells
> if an machine supports the API.
>
> @Russell: Do you have an opinion regarding this!?

Only that the kernels Kconfig is turning into a real complicated mess
of dependencies IMHO.

We could add a HAVE_CLK and add that to the dependency of all the drivers
which use linux/clk.h. The problem will be finding all those drivers and
their corresponding Kconfig entries.

My feeling is that we're just going to end up creating another Kconfig
symbol which folk half-heartedly use.
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