Re: [PATCH] drm/rcar-du: Convert to of_drm_find_and_get_bridge()

[Luca Ceresoli]

Hello Amin,

On Thu Mar 26, 2026 at 9:10 PM CET, Amin GATTOUT wrote:
> of_drm_find_bridge() is deprecated.
> Replace it with of_drm_find_and_get_bridge() which increments
> the bridge refcount as required.

Thanks for taking care of the conversion to the new API!

> --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_encoder.c
> @@ -72,7 +72,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>  		if (IS_ERR(bridge))
>  			return PTR_ERR(bridge);
>  	} else {
> -		bridge = of_drm_find_bridge(enc_node);
> +		bridge = of_drm_find_and_get_bridge(enc_node);

This change alone is not correct I'm afraid. The difference between
of_drm_find_bridge() and of_drm_find_and_get_bridge() is the latter get a
reference to the bridge, so you have to put that reference when the bridge
pointer is no more accessible.

Have a look at previous commits doing the same API replacement, you can
find examples similar to this one, where:

 * the bridge pointer is stored in a local variable (not saved in a struct)
 * the bridge pointer could be set wither by of_drm_find_bridge() or
   a function adding a panel bridge

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com