Re: [PATCH] ASoC: meson: add helpers for clk_disable_unprepare

[Jerome Brunet <jbrunet@xxxxxxxxxxxx>]

On Tue 13 Feb 2024 at 11:11, Arnd Bergmann <arnd@xxxxxxxxxx> wrote:

> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> Casting between incompatible function types causes a warning with clang-16
> because it breaks control flow integrity (KCFI) rules:
>
> sound/soc/meson/aiu.c:243:12: error: cast from 'void (*)(struct clk *)' to
> 'void (*)(void *)' converts to incompatible function type
> [-Werror,-Wcast-function-type-strict]
>   243 |                                        (void(*)(void *))clk_disable_unprepare,
>       |                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/device.h:406:34: note: expanded from macro 'devm_add_action_or_reset'
>   406 |         __devm_add_action_or_reset(dev, action, data, #action)
>       |                                         ^~~~~~
> sound/soc/meson/t9015.c:274:4: error: cast from 'void (*)(struct clk *)' to
> 'void (*)(void *)' converts to incompatible function type
> [-Werror,-Wcast-function-type-strict]
>   274 |                         (void(*)(void *))clk_disable_unprepare,
>       |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/device.h:406:34: note: expanded from macro 'devm_add_action_or_reset'
>   406 |         __devm_add_action_or_reset(dev, action, data, #action)
>       |                                         ^~~~~~
>
> These two meson drivers cast clk_disable_unprepare() into a different type
> in order to have it automatically called from the driver relase. Add
> trivial helpers to do the same using correct types.
>
> Fixes: 33901f5b9b16 ("ASoC: meson: add t9015 internal DAC driver")
> Fixes: 6ae9ca9ce986 ("ASoC: meson: aiu: add i2s and spdif support")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
>  sound/soc/meson/aiu.c   | 9 ++++++---
>  sound/soc/meson/t9015.c | 9 ++++++---
>  2 files changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/sound/soc/meson/aiu.c b/sound/soc/meson/aiu.c
> index 7109b81cc3d0..211f360df284 100644
> --- a/sound/soc/meson/aiu.c
> +++ b/sound/soc/meson/aiu.c
> @@ -209,6 +209,11 @@ static const char * const aiu_spdif_ids[] = {
>  	[MCLK]	= "spdif_mclk_sel"
>  };
>  
> +static void aiu_clk_disable(void *clk)
> +{
> +	clk_disable_unprepare(clk);
> +}
> +
>  static int aiu_clk_get(struct device *dev)
>  {
>  	struct aiu *aiu = dev_get_drvdata(dev);
> @@ -239,9 +244,7 @@ static int aiu_clk_get(struct device *dev)
>  		return ret;
>  	}
>  
> -	ret = devm_add_action_or_reset(dev,
> -				       (void(*)(void *))clk_disable_unprepare,
> -				       aiu->pclk);
> +	ret = devm_add_action_or_reset(dev, aiu_clk_disable, aiu->pclk);

Hi Arnd,

This probably pre-dates the introduction of devm_clk_get_enabled()
It would probably be better to use that instead of duplicating helper
functions which do the same thing.

If for any reason it is not possible, a common helper in clk.h would
preferable I think.

>  	if (ret)
>  		dev_err(dev, "failed to add reset action on pclk");
>  
> diff --git a/sound/soc/meson/t9015.c b/sound/soc/meson/t9015.c
> index 9c6b4dac6893..e0f9a603a5e9 100644
> --- a/sound/soc/meson/t9015.c
> +++ b/sound/soc/meson/t9015.c
> @@ -243,6 +243,11 @@ static const struct regmap_config t9015_regmap_config = {
>  	.max_register		= POWER_CFG,
>  };
>  
> +static void t9015_clk_disable(void *clk)
> +{
> +	clk_disable_unprepare(clk);
> +}
> +
>  static int t9015_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -270,9 +275,7 @@ static int t9015_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = devm_add_action_or_reset(dev,
> -			(void(*)(void *))clk_disable_unprepare,
> -			priv->pclk);
> +	ret = devm_add_action_or_reset(dev, t9015_clk_disable, priv->pclk);
>  	if (ret)
>  		return ret;


-- 
Jerome