drm: rcar-du: Skip encoder allocation for LVDS1 in dual-link mode

The rcar-du driver skips registration of the encoder for the LVDS1
output when LVDS is used in dual-link mode, as the LVDS0 and LVDS1 links
are bundled and handled through the LVDS0 output. It however still
allocates the encoder and immediately destroys it, which is pointless.
Skip allocation of the encoder altogether in that case.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/rcar_du_encoder.c

@@ -65,16 +65,6 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
 	struct drm_bridge *bridge;
 	int ret;
 
-	renc = kzalloc(sizeof(*renc), GFP_KERNEL);
-	if (renc == NULL)
-		return -ENOMEM;
-
-	renc->output = output;
-	encoder = rcar_encoder_to_drm_encoder(renc);
-
-	dev_dbg(rcdu->dev, "initializing encoder %pOF for output %u\n",
-		enc_node, output);
-
 	/*
 	 * Locate the DRM bridge from the DT node. For the DPAD outputs, if the
 	 * DT node has a single port, assume that it describes a panel and
@@ -85,23 +75,17 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
 	    rcar_du_encoder_count_ports(enc_node) == 1) {
 		struct drm_panel *panel = of_drm_find_panel(enc_node);
 
-		if (IS_ERR(panel)) {
-			ret = PTR_ERR(panel);
-			goto error;
-		}
+		if (IS_ERR(panel))
+			return PTR_ERR(panel);
 
 		bridge = devm_drm_panel_bridge_add_typed(rcdu->dev, panel,
 							 DRM_MODE_CONNECTOR_DPI);
-		if (IS_ERR(bridge)) {
-			ret = PTR_ERR(bridge);
-			goto error;
-		}
+		if (IS_ERR(bridge))
+			return PTR_ERR(bridge);
 	} else {
 		bridge = of_drm_find_bridge(enc_node);
-		if (!bridge) {
-			ret = -EPROBE_DEFER;
-			goto error;
-		}
+		if (!bridge)
+			return -EPROBE_DEFER;
 
 		if (output == RCAR_DU_OUTPUT_LVDS0 ||
 		    output == RCAR_DU_OUTPUT_LVDS1)
@@ -109,20 +93,31 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
 	}
 
 	/*
-	 * On Gen3 skip the LVDS1 output if the LVDS1 encoder is used as a
-	 * companion for LVDS0 in dual-link mode.
+	 * Create and initialize the encoder. On Gen3 skip the LVDS1 output if
+	 * the LVDS1 encoder is used as a companion for LVDS0 in dual-link
+	 * mode.
 	 */
 	if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) {
-		if (rcar_lvds_dual_link(bridge)) {
-			ret = -ENOLINK;
-			goto error;
-		}
+		if (rcar_lvds_dual_link(bridge))
+			return -ENOLINK;
 	}
 
+	renc = kzalloc(sizeof(*renc), GFP_KERNEL);
+	if (renc == NULL)
+		return -ENOMEM;
+
+	renc->output = output;
+	encoder = rcar_encoder_to_drm_encoder(renc);
+
+	dev_dbg(rcdu->dev, "initializing encoder %pOF for output %u\n",
+		enc_node, output);
+
 	ret = drm_encoder_init(&rcdu->ddev, encoder, &rcar_du_encoder_funcs,
 			       DRM_MODE_ENCODER_NONE, NULL);
-	if (ret < 0)
-		goto error;
+	if (ret < 0) {
+		kfree(renc);
+		return ret;
+	}
 
 	ret = drmm_add_action_or_reset(&rcdu->ddev, rcar_du_encoder_release,
 				       renc);
@@ -134,8 +129,4 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
 	 * connector.
 	 */
 	return drm_bridge_attach(encoder, bridge, NULL, 0);
-
-error:
-	kfree(renc);
-	return ret;
 }