drm: rcar-du: lvds: Improve identification of panels

Dual-LVDS panels are mistakenly identified as bridges, this
commit replaces the current logic with a call to
drm_of_find_panel_or_bridge to sort that out.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

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

@@ -21,6 +21,7 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_probe_helper.h>
 
@@ -712,79 +713,23 @@ static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
 
 static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
 {
-	struct device_node *local_output = NULL;
-	struct device_node *remote_input = NULL;
-	struct device_node *remote = NULL;
-	struct device_node *node;
-	bool is_bridge = false;
-	int ret = 0;
-
-	local_output = of_graph_get_endpoint_by_regs(lvds->dev->of_node, 1, 0);
-	if (!local_output) {
-		dev_dbg(lvds->dev, "unconnected port@1\n");
-		ret = -ENODEV;
-		goto done;
-	}
-
-	/*
-	 * Locate the connected entity and infer its type from the number of
-	 * endpoints.
-	 */
-	remote = of_graph_get_remote_port_parent(local_output);
-	if (!remote) {
-		dev_dbg(lvds->dev, "unconnected endpoint %pOF\n", local_output);
-		ret = -ENODEV;
-		goto done;
-	}
+	int ret;
 
-	if (!of_device_is_available(remote)) {
-		dev_dbg(lvds->dev, "connected entity %pOF is disabled\n",
-			remote);
-		ret = -ENODEV;
+	ret = drm_of_find_panel_or_bridge(lvds->dev->of_node, 1, 0,
+					  &lvds->panel, &lvds->next_bridge);
+	if (ret)
 		goto done;
-	}
 
-	remote_input = of_graph_get_remote_endpoint(local_output);
-
-	for_each_endpoint_of_node(remote, node) {
-		if (node != remote_input) {
-			/*
-			 * We've found one endpoint other than the input, this
-			 * must be a bridge.
-			 */
-			is_bridge = true;
-			of_node_put(node);
-			break;
-		}
-	}
-
-	if (is_bridge) {
-		lvds->next_bridge = of_drm_find_bridge(remote);
-		if (!lvds->next_bridge) {
-			ret = -EPROBE_DEFER;
-			goto done;
-		}
-
-		if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
-			lvds->dual_link = lvds->next_bridge->timings
-					? lvds->next_bridge->timings->dual_link
-					: false;
-	} else {
-		lvds->panel = of_drm_find_panel(remote);
-		if (IS_ERR(lvds->panel)) {
-			ret = PTR_ERR(lvds->panel);
-			goto done;
-		}
-	}
+	if ((lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) &&
+	    lvds->next_bridge)
+		lvds->dual_link = lvds->next_bridge->timings
+				? lvds->next_bridge->timings->dual_link
+				: false;
 
 	if (lvds->dual_link)
 		ret = rcar_lvds_parse_dt_companion(lvds);
 
 done:
-	of_node_put(local_output);
-	of_node_put(remote_input);
-	of_node_put(remote);
-
 	/*
 	 * On D3/E3 the LVDS encoder provides a clock to the DU, which can be
 	 * used for the DPAD output even when the LVDS output is not connected.