Re: [PATCH 2/4] drm: renesas: rz-du: Make DU reset control optional for RZ/T2H support

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Apr 29, 2026 at 06:00:10PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Update the DU CRTC initialisation to request the reset control using
> devm_reset_control_get_optional_shared(). On RZ/T2H SoCs the DU block does
> not expose a reset line, and treating the reset as mandatory prevents the
> driver from probing on those platforms.

This assume a device tree compliant with the bindings. In case of a
non-compliant device tree on platforms other than RZ/T2H, the driver may
silently fail to work as it won't complain about the lack of reset. I
think that's acceptable, as the reset should be specified in the SoC's
.dtsi. If if was the responsibility of board DT authors I would be a bit
more concerned.

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>  drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
> index 18e2b981b691..2b772a11c7ee 100644
> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
> @@ -380,7 +380,7 @@ int rzg2l_du_crtc_create(struct rzg2l_du_device *rcdu)
>  	struct drm_plane *primary;
>  	int ret;
>  
> -	rcrtc->rstc = devm_reset_control_get_shared(rcdu->dev, NULL);
> +	rcrtc->rstc = devm_reset_control_get_optional_shared(rcdu->dev, NULL);
>  	if (IS_ERR(rcrtc->rstc)) {
>  		dev_err(rcdu->dev, "can't get cpg reset\n");
>  		return PTR_ERR(rcrtc->rstc);

-- 
Regards,

Laurent Pinchart