Re: [PATCH v2] clk: ralink: mtmips: quiet unused variable warning

[Nathan Chancellor <nathan@kernel.org>]

On Sun, Aug 27, 2023 at 04:39:32AM +0200, Sergio Paracuellos 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[] = {
>     |                          ^
> 
> There are two match tables in the driver: one for the clock driver and the
> other for the reset driver. The only difference between them is that the
> clock driver uses 'data' and does not have 'ralink,rt2880-reset' compatible.
> Both just can be merged into a single one just by adding the compatible
> 'ralink,rt2880-reset' entry to 'mtmips_of_match[]', which will allow it to
> be used for 'mtmips_clk_driver' (which doesn't use the data) as well as for
> 'mtmips_clk_init()' (which doesn't need get called for 'ralink,rt2880-reset').
> 
> Doing in this way ensures that 'CONFIG_OF' is not disabled anymore so the
> above warning disapears.
> 
> Fixes: 6f3b15586eef ("clk: ralink: add clock and reset driver for MTMIPS SoCs")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202307242310.CdOnd2py-lkp@intel.com/
> Suggested-by: Arnd Bergmann <arnd@kernel.org>
> Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
> Changes in v2:
> - Merge two match tables into one to properly avoid this warning.
> 
> PATCH in v1: https://lore.kernel.org/lkml/20230802092647.3000666-1-sergio.paracuellos@gmail.com/T/
> 
>  drivers/clk/ralink/clk-mtmips.c | 20 +++++---------------
>  1 file changed, 5 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/clk/ralink/clk-mtmips.c b/drivers/clk/ralink/clk-mtmips.c
> index 1e7991439527..50a443bf79ec 100644
> --- a/drivers/clk/ralink/clk-mtmips.c
> +++ b/drivers/clk/ralink/clk-mtmips.c
> @@ -821,6 +821,10 @@ static const struct mtmips_clk_data mt76x8_clk_data = {
>  };
>  
>  static const struct of_device_id mtmips_of_match[] = {
> +	{
> +		.compatible = "ralink,rt2880-reset",
> +		.data = NULL,
> +	},
>  	{
>  		.compatible = "ralink,rt2880-sysc",
>  		.data = &rt2880_clk_data,
> @@ -1088,25 +1092,11 @@ static int mtmips_clk_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -static const struct of_device_id mtmips_clk_of_match[] = {
> -	{ .compatible = "ralink,rt2880-reset" },
> -	{ .compatible = "ralink,rt2880-sysc" },
> -	{ .compatible = "ralink,rt3050-sysc" },
> -	{ .compatible = "ralink,rt3052-sysc" },
> -	{ .compatible = "ralink,rt3352-sysc" },
> -	{ .compatible = "ralink,rt3883-sysc" },
> -	{ .compatible = "ralink,rt5350-sysc" },
> -	{ .compatible = "ralink,mt7620-sysc" },
> -	{ .compatible = "ralink,mt7628-sysc" },
> -	{ .compatible = "ralink,mt7688-sysc" },
> -	{}
> -};
> -
>  static struct platform_driver mtmips_clk_driver = {
>  	.probe = mtmips_clk_probe,
>  	.driver = {
>  		.name = "mtmips-clk",
> -		.of_match_table = mtmips_clk_of_match,
> +		.of_match_table = mtmips_of_match,
>  	},
>  };
>  
> -- 
> 2.25.1
>