Re: [PATCH v4 4/4] drm/omap: dss: convert to of_drm_find_and_get_bridge()

[Louis Chauvet <louis.chauvet@bootlin.com>]

On 4/2/26 18:27, Luca Ceresoli wrote:
> of_drm_find_bridge() is deprecated. Move to its replacement
> of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
> is put when done.
> 
> omapdss_device_init_output() can take one bridge pointer in out->bridge or
> two pointers in out->bridge and out->next_bridge. Ensure each has a
> corresponding drm_bridge_get() and add drm_bridge_put() calls in the
> cleanup code.
> 
> Also slightly change the initial code assigning out->panel and out->bridge
> to ensure and clarify that either out->panel or out->bridge is set in the
> function prologue, not both. If both were set, the 'if (out->panel){...}'
> code that follows would overwrite out->bridge without having put the
> reference.
> 
> Finally, take a reference in case a panel_bridge is added using
> drm_panel_bridge_add(). This ensures we always need to put a reference,
> which came either from of_drm_find_and_get_bridge() or by the
> drm_panel_bridge_add+drm_bridge_get() branch.
> 
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>

> ---
>   drivers/gpu/drm/omapdrm/dss/output.c | 11 ++++++++---
>   1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/dss/output.c b/drivers/gpu/drm/omapdrm/dss/output.c
> index 7378e855c278..ca891aba3820 100644
> --- a/drivers/gpu/drm/omapdrm/dss/output.c
> +++ b/drivers/gpu/drm/omapdrm/dss/output.c
> @@ -30,11 +30,13 @@ int omapdss_device_init_output(struct omap_dss_device *out,
>   		return 0;
>   	}
>   
> -	out->bridge = of_drm_find_bridge(remote_node);
>   	out->panel = of_drm_find_panel(remote_node);
>   	if (IS_ERR(out->panel))
>   		out->panel = NULL;
>   
> +	if (!out->panel)
> +		out->bridge = of_drm_find_and_get_bridge(remote_node);
> +
>   	of_node_put(remote_node);
>   
>   	if (out->panel) {
> @@ -49,7 +51,7 @@ int omapdss_device_init_output(struct omap_dss_device *out,
>   			goto error;
>   		}
>   
> -		out->bridge = bridge;
> +		out->bridge = drm_bridge_get(bridge);
>   	}
>   
>   	if (local_bridge) {
> @@ -59,7 +61,7 @@ int omapdss_device_init_output(struct omap_dss_device *out,
>   		}
>   
>   		out->next_bridge = out->bridge;
> -		out->bridge = local_bridge;
> +		out->bridge = drm_bridge_get(local_bridge);
>   	}
>   
>   	if (!out->bridge) {
> @@ -79,6 +81,9 @@ void omapdss_device_cleanup_output(struct omap_dss_device *out)
>   	if (out->bridge && out->panel)
>   		drm_panel_bridge_remove(out->next_bridge ?
>   					out->next_bridge : out->bridge);
> +
> +	drm_bridge_put(out->next_bridge);
> +	drm_bridge_put(out->bridge);
>   }
>   
>   void dss_mgr_set_timings(struct omap_dss_device *dssdev,
>