Re: [PATCH 1/2] hwmon: gpio-fan: mark OF related data as maybe unused

[Guenter Roeck]

On 3/12/23 11:08, Krzysztof Kozlowski wrote:
> On 12/03/2023 19:06, Guenter Roeck wrote:
> > On Sat, Mar 11, 2023 at 12:16:09PM +0100, Krzysztof Kozlowski wrote:
> > > The driver can be compile tested with !CONFIG_OF making certain data
> > > unused:
> > >
> > >    drivers/hwmon/gpio-fan.c:484:34: error: ‘of_gpio_fan_match’ defined but not used [-Werror=unused-const-variable=]
> >
> > How do you trigger that ? The driver depends on OF_GPIO which
> > in turn depends on OF. Arguably that means that of_match_ptr()
> > doesnot really make sense, but still I don't see how you can
> > trigger the above error message.
>
> I can drop of_match_ptr, it's indeed in many cases not needed.
>
> I just build x86_64 allyesconfig minus OF, with W=1.

x86_64 allyesconfig minus OF minus results in SENSORS_GPIO_FAN being
deselected (it doesn't show up in the configuration anymore at all
after "make olddefconfig").

$ make allyesconfig
$ grep SENSORS_GPIO_FAN .config
CONFIG_SENSORS_GPIO_FAN=y
$ sed -i -e 's/CONFIG_OF=y/# CONFIG_OF is not set/' .config
$ make olddefconfig
#
# configuration written to .config
#
$ grep SENSORS_GPIO_FAN .config
$

I suspect what you did is to disable CONFIG_OF, and then you built
the driver without realizing that is was deselected.

> Do you want to me to drop of_match_ptr?

Yes, sure, that makes more sense. The reason though is that the
driver depends on CONFIG_OF=y, not because of the build failure.

Thanks,
Guenter