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Date:   Wed, 20 Sep 2023 10:52:48 +0100
From:   Lee Jones <lee@kernel.org>
To:     zhangshida <starzhangzsd@gmail.com>
Cc:     linux-kernel@vger.kernel.org, zhangshida@kylinos.cn,
        k2ci <kernel-bot@kylinos.cn>
Subject: Re: [PATCH] mfd: cs42l43: fix defined but not used warnings
Message-ID: <20230920095248.GC13143@google.com>
References: <20230905021209.1412987-1-zhangshida@kylinos.cn>
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On Tue, 05 Sep 2023, zhangshida wrote:

> From: Shida Zhang <zhangshida@kylinos.cn>
> 
> Warnings were generated during compiling for functions like
> cs42l43_*_{resume,suspend}:
> 
> ../drivers/mfd/cs42l43.c:1138:12: error: ‘cs42l43_runtime_resume’ defined but not used [-Werror=unused-function]
>  1138 | static int cs42l43_runtime_resume(struct device *dev)
>       |            ^~~~~~~~~~~~~~~~~~~~~~
> ../drivers/mfd/cs42l43.c:1124:12: error: ‘cs42l43_runtime_suspend’ defined but not used [-Werror=unused-function]
>  1124 | static int cs42l43_runtime_suspend(struct device *dev)
>       |            ^~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/mfd/cs42l43.c:1106:12: error: ‘cs42l43_resume’ defined but not used [-Werror=unused-function]
>  1106 | static int cs42l43_resume(struct device *dev)
>       |            ^~~~~~~~~~~~~~
> ../drivers/mfd/cs42l43.c:1076:12: error: ‘cs42l43_suspend’ defined but not used [-Werror=unused-function]
>  1076 | static int cs42l43_suspend(struct device *dev)
> 
> Fix it by guarding it with CONFIG_PM/CONFIG_PM_SLEEP.
> 
> Reported-by: k2ci <kernel-bot@kylinos.cn>
> Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
> ---
>  drivers/mfd/cs42l43.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/mfd/cs42l43.c b/drivers/mfd/cs42l43.c
> index 37b23e9bae82..e589a61c118d 100644
> --- a/drivers/mfd/cs42l43.c
> +++ b/drivers/mfd/cs42l43.c
> @@ -1073,6 +1073,7 @@ void cs42l43_dev_remove(struct cs42l43 *cs42l43)
>  }
>  EXPORT_SYMBOL_NS_GPL(cs42l43_dev_remove, MFD_CS42L43);
>  
> +#ifdef CONFIG_PM_SLEEP
>  static int cs42l43_suspend(struct device *dev)
>  {
>  	struct cs42l43 *cs42l43 = dev_get_drvdata(dev);
> @@ -1120,7 +1121,9 @@ static int cs42l43_resume(struct device *dev)
>  
>  	return 0;
>  }
> +#endif
>  
> +#ifdef CONFIG_PM
>  static int cs42l43_runtime_suspend(struct device *dev)
>  {
>  	struct cs42l43 *cs42l43 = dev_get_drvdata(dev);
> @@ -1176,6 +1179,7 @@ static int cs42l43_runtime_resume(struct device *dev)
>  
>  	return ret;
>  }
> +#endif
>  
>  EXPORT_NS_GPL_DEV_PM_OPS(cs42l43_pm_ops, MFD_CS42L43) = {
>  	SET_SYSTEM_SLEEP_PM_OPS(cs42l43_suspend, cs42l43_resume)

I see a bunch of drivers using PM helpers and not many of them are
are being guarded by ugly #ifery.  Please find out what they're doing to
solve the same issue and replicate that instead.

Here's a really big hint:

  `git log --oneline 02313a90095fb`

-- 
Lee Jones [李琼斯]