Re: [PATCH] drm/bridge: panel: Return always an error pointer in drm_panel_bridge_add()

From: Laurent Pinchart
Date: Thu Apr 16 2020 - 17:46:52 EST


Hi Enric,

Thank you for the patch.

On Thu, Apr 16, 2020 at 11:06:54PM +0200, Enric Balletbo i Serra wrote:
> Since commit 89958b7cd955 ("drm/bridge: panel: Infer connector type from
> panel by default"), drm_panel_bridge_add() and their variants can return
> NULL and an error pointer. This is fine but none of the actual users of
> the API are checking for the NULL value. Instead of change all the
> users, seems reasonable to return an error pointer instead. So change
> the returned value for those functions when the connector type is unknown.
>
> Suggested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>

Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>

> ---
>
> drivers/gpu/drm/bridge/panel.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
> index 8461ee8304ba..7a3df0f319f3 100644
> --- a/drivers/gpu/drm/bridge/panel.c
> +++ b/drivers/gpu/drm/bridge/panel.c
> @@ -166,7 +166,7 @@ static const struct drm_bridge_funcs panel_bridge_bridge_funcs = {
> *
> * The connector type is set to @panel->connector_type, which must be set to a
> * known type. Calling this function with a panel whose connector type is
> - * DRM_MODE_CONNECTOR_Unknown will return NULL.
> + * DRM_MODE_CONNECTOR_Unknown will return ERR_PTR(-EINVAL).
> *
> * See devm_drm_panel_bridge_add() for an automatically managed version of this
> * function.
> @@ -174,7 +174,7 @@ static const struct drm_bridge_funcs panel_bridge_bridge_funcs = {
> struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel)
> {
> if (WARN_ON(panel->connector_type == DRM_MODE_CONNECTOR_Unknown))
> - return NULL;
> + return ERR_PTR(-EINVAL);
>
> return drm_panel_bridge_add_typed(panel, panel->connector_type);
> }
> @@ -265,7 +265,7 @@ struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
> struct drm_panel *panel)
> {
> if (WARN_ON(panel->connector_type == DRM_MODE_CONNECTOR_Unknown))
> - return NULL;
> + return ERR_PTR(-EINVAL);
>
> return devm_drm_panel_bridge_add_typed(dev, panel,
> panel->connector_type);

--
Regards,

Laurent Pinchart