linux-kernel - Re: [PATCH] cpufreq: s3c64xx: hide unused variable

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Message-ID: <20250122065834.c4va6uwjrfny2mfv@vireshk-i7>
Date: Wed, 22 Jan 2025 12:28:34 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Arnd Bergmann <arnd@...nel.org>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
	Krzysztof Kozlowski <krzk@...nel.org>,
	Arnd Bergmann <arnd@...db.de>,
	Alim Akhtar <alim.akhtar@...sung.com>, linux-pm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: s3c64xx: hide unused variable

On 22-01-25, 07:52, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> A previous compiler warning fix extended an #ifdef block, but that
> led to another warning in some builds:
> 
> drivers/cpufreq/s3c64xx-cpufreq.c:27:28: error: 's3c64xx_dvfs_table' defined but not used [-Werror=unused-variable]
>    27 | static struct s3c64xx_dvfs s3c64xx_dvfs_table[] = {
> 
> Add yet another #ifdef check around that variable.
> 
> Fixes: 76b218721e5f ("cpufreq: s3c64xx: Fix compilation warning")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---

I too have sent a fix this morning:
236b227e929e5adc04d1e9e7af6845a46c8e9432.1737525916.git.viresh.kumar@...aro.org

> I wonder if the driver should instead depend on CONFIG_REGULATOR
> and drop the #ifdef checks.

The way CONFIG_REGULATOR is used in the driver, it seems like it can
be used without regulators too. The initial commit also confirms this.

commit b3748ddd80569ec753f62e709629b8c639143222
Author: Mark Brown <broonie@...nsource.wolfsonmicro.com>
Date:   Mon Jun 15 11:23:20 2009 +0100

    [ARM] S3C64XX: Initial support for DVFS

    This patch provides initial support for CPU frequency scaling on the
    Samsung S3C ARM processors. Currently only S3C6410 processors are
    supported, though addition of another data table with supported clock
    rates should be sufficient to enable support for further CPUs.

    Use the regulator framework to provide optional support for DVFS in
    the S3C cpufreq driver. When a software controllable regulator is
    configured the driver will use it to lower the supply voltage when
    running at a lower frequency, giving improved power savings.

    When regulator support is disabled or no regulator can be obtained
    for VDDARM the driver will fall back to scaling only the frequency.

    Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
    Signed-off-by: Ben Dooks <ben-linux@...ff.org>

-- 
viresh