UPSTREAM: drm/exynos: dp: Fix panel and bridge lookup logic

Commit a9fa852886fd ("drm/exynos: dp: add of_graph dt binding support
for panel") made the Exynos DP DT binding more consistent since the OF
graph could be used to lookup either a panel or a bridge device node.

Before that commit, a panel would be looked up using a phandle and a
bridge using the OF graph which made the DT binding not consistent.

But the patch broke the later case since not finding a panel dev node
would cause the driver's to do a probe deferral instead of attempting
to lookup a bridge device node associated with the remote endpoint.

So instead of returning a -EPROBE_DEFER if a panel is not found, check
if there's a bridge and only do a probe deferral if both aren't found.

(cherry picked from commit 37e110625eeeaba83e8cb763ab7645f0678c6f8e)

Change-Id: If8b66d792447d4e3455f99dc38b04f334b8b65a6
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Michal Suchanek <hramrach@gmail.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Yakir Yang <ykk@rock-chips.com>

diff --git a/drivers/gpu/drm/exynos/exynos_dp_core.c b/drivers/gpu/drm/exynos/exynos_dp_core.c
index b79c316c2ad2ce7b7eb48e152a49c41ab6e93431..673164b331c8806e14aaa10d82e2f787c10bfb09 100644 (file)
--- a/drivers/gpu/drm/exynos/exynos_dp_core.c
+++ b/drivers/gpu/drm/exynos/exynos_dp_core.c
@@ -1392,7 +1392,7 @@ static const struct component_ops exynos_dp_ops = {
 static int exynos_dp_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
-       struct device_node *panel_node = NULL, *bridge_node, *endpoint = NULL;
+       struct device_node *np = NULL, *endpoint = NULL;
        struct exynos_dp_device *dp;
        int ret;
 
@@ -1404,41 +1404,36 @@ static int exynos_dp_probe(struct platform_device *pdev)
        platform_set_drvdata(pdev, dp);
 
        /* This is for the backward compatibility. */
-       panel_node = of_parse_phandle(dev->of_node, "panel", 0);
-       if (panel_node) {
-               dp->panel = of_drm_find_panel(panel_node);
-               of_node_put(panel_node);
+       np = of_parse_phandle(dev->of_node, "panel", 0);
+       if (np) {
+               dp->panel = of_drm_find_panel(np);
+               of_node_put(np);
                if (!dp->panel)
                        return -EPROBE_DEFER;
-       } else {
-               endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
-               if (endpoint) {
-                       panel_node = of_graph_get_remote_port_parent(endpoint);
-                       if (panel_node) {
-                               dp->panel = of_drm_find_panel(panel_node);
-                               of_node_put(panel_node);
-                               if (!dp->panel)
-                                       return -EPROBE_DEFER;
-                       } else {
-                               DRM_ERROR("no port node for panel device.\n");
-                               return -EINVAL;
-                       }
-               }
-       }
-
-       if (endpoint)
                goto out;
+       }
 
        endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
        if (endpoint) {
-               bridge_node = of_graph_get_remote_port_parent(endpoint);
-               if (bridge_node) {
-                       dp->ptn_bridge = of_drm_find_bridge(bridge_node);
-                       of_node_put(bridge_node);
-                       if (!dp->ptn_bridge)
-                               return -EPROBE_DEFER;
-               } else
-                       return -EPROBE_DEFER;
+               np = of_graph_get_remote_port_parent(endpoint);
+               if (np) {
+                       /* The remote port can be either a panel or a bridge */
+                       dp->panel = of_drm_find_panel(np);
+                       if (!dp->panel) {
+                               dp->ptn_bridge = of_drm_find_bridge(np);
+                               if (!dp->ptn_bridge) {
+                                       of_node_put(np);
+                                       return -EPROBE_DEFER;
+                               }
+                       }
+                       of_node_put(np);
+               } else {
+                       DRM_ERROR("no remote endpoint device node found.\n");
+                       return -EINVAL;
+               }
+       } else {
+               DRM_ERROR("no port endpoint subnode found.\n");
+               return -EINVAL;
        }
 
 out: