Re: [PATCH 1/2] ptp_clock: allow for it to be optional

From	Josh Triplett <josh@joshtriplett.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/2] ptp_clock: allow for it to be optional
Date	2016-09-19 19:40 +0200
Message-ID	<sjaHT-8o6-11@gated-at.bofh.it> (permalink)
References	<siY41-za-3@gated-at.bofh.it> <siY41-za-1@gated-at.bofh.it> <sj5RU-5pe-15@gated-at.bofh.it> <sj7Al-6uD-3@gated-at.bofh.it> <sjaeR-8dK-17@gated-at.bofh.it>
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On Mon, Sep 19, 2016 at 07:04:15PM +0200, Jiri Benc wrote:
> On Mon, 19 Sep 2016 10:10:21 -0400 (EDT), Nicolas Pitre wrote:
> > --- a/include/linux/ptp_clock_kernel.h
> > +++ b/include/linux/ptp_clock_kernel.h
> > @@ -207,7 +207,16 @@ int ptp_find_pin(struct ptp_clock *ptp,
> >  #else
> >  static inline struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
> >  						   struct device *parent)
> > -{ return NULL; }
> > +{
> > +	if (IS_MODULE(CONFIG_PTP_1588_CLOCK)) {
> > +		pr_warn("%s is built-in while PTP clock subsystem is modular, "
> > +			"PTP clock ignored\n", KBUILD_MODNAME);
> > +	} else {
> > +		pr_warn("ignoring PTP clock from %s as PTP clock subsystem "
> > +			"is configured out\n", KBUILD_MODNAME);
> > +	}
> > +	return NULL;
> > +}
> 
> I think the else part is not needed. If PTP is disabled, it is
> disabled, nobody should be surprised by that. Looks good otherwise.

This works, and it should compile away to nothing in the normal case.
But it does seem unfortunate that this can't happen at build time via
Kconfig.  CCing linux-kbuild in case someone has an idea for how to fix
this.

Thread

[PATCH 1/2] ptp_clock: allow for it to be optional Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-09-19 06:10 +0200
  Re: [PATCH 1/2] ptp_clock: allow for it to be optional Jiri Benc <jbenc@redhat.com> - 2016-09-19 14:30 +0200
    Re: [PATCH 1/2] ptp_clock: allow for it to be optional Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-09-19 16:20 +0200
      Re: [PATCH 1/2] ptp_clock: allow for it to be optional Jiri Benc <jbenc@redhat.com> - 2016-09-19 19:10 +0200
        Re: [PATCH 1/2] ptp_clock: allow for it to be optional Josh Triplett <josh@joshtriplett.org> - 2016-09-19 19:40 +0200
          Re: [PATCH 1/2] ptp_clock: allow for it to be optional Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-09-19 20:20 +0200
  Re: [PATCH 1/2] ptp_clock: allow for it to be optional Eugenia Emantayev <eugenia.emantayev@gmail.com> - 2016-09-19 14:30 +0200

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