[PATCH] drm: rcar-du: Fix Kconfig dependency between RCAR_DU and RCAR_MIPI_DSI

[Tomi Valkeinen]

Hi,

On 02/10/2022 01:03, Laurent Pinchart wrote:
> When the R-Car MIPI DSI driver was added, it was a standalone encoder
> driver without any dependency to or from the R-Car DU driver. Commit
> 957fe62d7d15 ("drm: rcar-du: Fix DSI enable & disable sequence") then
> added a direct call from the DU driver to the MIPI DSI driver, without
> updating Kconfig to take the new dependency into account. Fix it the
> same way that the LVDS encoder is handled.
> 
> Fixes: 957fe62d7d15 ("drm: rcar-du: Fix DSI enable & disable sequence")
> Reported-by: kernel test robot <lkp at intel.com>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> ---
>   drivers/gpu/drm/rcar-du/Kconfig | 13 +++++++++----
>   1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/Kconfig b/drivers/gpu/drm/rcar-du/Kconfig
> index c959e8c6be7d..fd2c2eaee26b 100644
> --- a/drivers/gpu/drm/rcar-du/Kconfig
> +++ b/drivers/gpu/drm/rcar-du/Kconfig
> @@ -44,12 +44,17 @@ config DRM_RCAR_LVDS
>   	select OF_FLATTREE
>   	select OF_OVERLAY
>   
> +config DRM_RCAR_USE_MIPI_DSI
> +	bool "R-Car DU MIPI DSI Encoder Support"
> +	depends on DRM_BRIDGE && OF
> +	default DRM_RCAR_DU
> +	help
> +	  Enable support for the R-Car Display Unit embedded MIPI DSI encoders.
> +
>   config DRM_RCAR_MIPI_DSI
> -	tristate "R-Car DU MIPI DSI Encoder Support"
> -	depends on DRM && DRM_BRIDGE && OF
> +	def_tristate DRM_RCAR_DU
> +	depends on DRM_RCAR_USE_MIPI_DSI
>   	select DRM_MIPI_DSI
> -	help
> -	  Enable support for the R-Car Display Unit embedded MIPI DSI encoders.
>   
>   config DRM_RCAR_VSP
>   	bool "R-Car DU VSP Compositor Support" if ARM
> 
> base-commit: 7860d720a84c74b2761c6b7995392a798ab0a3cb

Interesting dependency issue. Took me a while to understand it =).

But is there a reason to not have "depends on DRM_RCAR_DU" for 
DRM_RCAR_USE_MIPI_DSI and DRM_RCAR_USE_LVDS? Now the menu items are 
available even if RCAR_DU is n. That's also the case for 
DRM_RCAR_DW_HDMI, but I'm not sure if that's supposed to be usable even 
without RCAR_DU.

Reviewed-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>

  Tomi