Re: [PATCH] drivers: Let several drivers depends on HAS_IOMEM for 'devm_ioremap_resource'

[Guenter Roeck]

On 07/14/2014 05:34 PM, Chen Gang wrote:
> On 07/14/2014 05:22 PM, Chen Gang wrote:
> > å 2014å7æ14æïäå4:57ïRichard Weinberger <richard@xxxxxx> åéï
> >
> > > Am 14.07.2014 10:48, schrieb Lars-Peter Clausen:
> > > > On 07/14/2014 10:31 AM, Richard Weinberger wrote:
> > > > > Am 13.07.2014 22:17, schrieb Greg Kroah-Hartman:
> > > > > > On Sun, Jul 13, 2014 at 09:33:38PM +0200, Richard Weinberger wrote:
> > > > > > > Maybe we could add COMPILE_TEST to the version string too?
> > > > > > > Just to detect such kernels fast in user bug reports...
> > > > > >
> > > > > > What kind of bug report are you going to get?
> > > > >
> > > > > User manages to enable CONFIG_FOO by selecting COMPILE_TEST and
> > > > > complains that it does not work. :)
> > > >
> > > > These drivers are typically drivers for some SoC peripheral and the device will simply physically not exist on a platform that does not provide HAS_IOMEM. This is not really any
> > > > different from making the driver selectable via COMPILE_TEST for any other platform. To hit the issue you'd have to instantiate a device driver instance for a device that
> > > > physically does not exist. This will always result in a failure.
> > >
> > > Okay, you have convinced me. :)
>
> After search the history patches, I found one related patch which made
> by myself (when I am in Asianux):
>
>    "https://lkml.org/lkml/2013/7/1/641";
>
> For me, it is a long discussion, and forced many members have to join
> in. Please help check again.

One thing you could try would be to return NULL (or where appropriate
an error) in the #else case of CONFIG_HAS_IOMEM and CONFIG_HAS_IOPORT,
ie dont take COMPILE_TEST into account at all. Obviously that means
you won't be able to dump a warning message in the COMPILE_TEST
case, but at least the code would compile. The rejection of above patch
would make a good case for this approach.

Guenter

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