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Date:   Sat, 24 Jul 2021 16:16:35 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Andy Shevchenko <andy.shevchenko@gmail.com>,
        Sean Nyekjaer <sean@geanix.com>, Arnd Bergmann <arnd@arndb.de>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Linus Walleij <linus.walleij@linaro.org>,
        Stephan Gerhold <stephan@gerhold.net>,
        Hans de Goede <hdegoede@redhat.com>,
        Tomas Melin <tomas.melin@vaisala.com>,
        Mike Looijmans <mike.looijmans@topic.nl>,
        Alexandru Ardelean <aardelean@deviqon.com>,
        linux-iio@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] iio: accel: fxls8962af: fix i2c dependency
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On Wed, 21 Jul 2021 20:40:30 +0200
Arnd Bergmann <arnd@kernel.org> wrote:

> On Wed, Jul 21, 2021 at 7:34 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Wed, Jul 21, 2021 at 7:12 PM Arnd Bergmann <arnd@kernel.org> wrote:  
> > > On Wed, Jul 21, 2021 at 5:52 PM Andy Shevchenko
> > > <andy.shevchenko@gmail.com> wrote:  
> > > > On Wed, Jul 21, 2021 at 6:13 PM Arnd Bergmann <arnd@kernel.org> wrote:  
> >
> > ...
> >  
> > > > >  config FXLS8962AF
> > > > >         tristate
> > > > > +       depends on I2C || !I2C # cannot be built-in for modular I2C  
> > > >
> > > > Can you enlighten me how this will not be a no-op?  
> > >
> > > This part does nothing, it only causes a warning when FXLS8962AF
> > > gets selected =y when I2C=m.  
> >
> > This is something new to me. But shouldn't the other chunk guarantee
> > that warning won't happen?  
> 
> Correct, it works without that, but if that fails after something changes,
> this version would provide better diagnostics than the FXLS8962AF
> core driver causing a link failure, and I found it documents better
> why the other driver needs the dependency.
> 
> Let me know if you prefer me to resend the patch without this hunk.
> 
>       Arnd

Hi Arnd,

I didn't think of this particularly combination when we dealt with
last build issue the workaround brought in.  I've applied this to the
fixes-togreg branch of iio.git as an immediately solution, but longer
term we should think about just using a function pointer to allow us
to move this into the i2c specific module.  If we do that we can
drop this complex build logic later.

Thanks,

Jonathan