Re: [PATCH] clk: ralink: mtmips: quiet unused variable warning

From: Arnd Bergmann
Date: Wed Aug 02 2023 - 18:02:10 EST

On Wed, Aug 2, 2023, at 23:26, Nick Desaulniers wrote:
> On Wed, Aug 2, 2023 at 2:26 AM Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx> wrote:
>> When CONFIG_OF is disabled then the matching table is not referenced and
>> the following warning appears:
>> drivers/clk/ralink/clk-mtmips.c:821:34: warning: unused variable 'mtmips_of_match' [-Wunused-const-variable]
>> 821 | static const struct of_device_id mtmips_of_match[] = {
>> | ^
>> Silence it declaring 'mtmips_of_match' with '__maybe_unused'.
>> Fixes: 6f3b15586eef ("clk: ralink: add clock and reset driver for MTMIPS SoCs")
>> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>> Closes:
>> Signed-off-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx>
> I think this is fine; Arnd or Nathan do you have a preference? or thoughts here?
> If not, thanks for the patch.
> Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> (I have a slight preference for wrapping the use in `#ifdef CONFIG_OF`
> since with the approach used by this patch, if all users are removed
> we will never get a warning for this var. But it's a weak preference;
> it's more important to me that we don't have -Werror promote this
> warning to a build breakage)

I don't understand why there are two match tables in the same
driver, with almost the same contents. I have not looked very
closely here, but why can't we just drop the mtmips_clk_of_match[]
table (the one without the .data fields) and use the same
table for both? Is this because of the ralink,rt2880-reset entry
that is missing in mtmips_of_match, or is that another bug?

I also see that there is both a platform_driver instance for
late probing and a list of CLK_OF_DECLARE_DRIVER() entries.
Do we need both here?