Merge tag 'arcpgu-updates-2019.07.18' of github.com:abrodkin/linux into drm-next

This is a pretty simple improvement that allows to find encoder
as the one and only (ARC PGU doesn't support more than one) endpoint
instead of using non-standard "encoder-slave" property.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Link: https://patchwork.freedesktop.org/patch/msgid/CY4PR1201MB0120FDB10A777345F9C27720A1C90@CY4PR1201MB0120.namprd12.prod.outlook.com

drivers/gpu/drm/arc/arcpgu_drv.c

@@ -14,6 +14,7 @@
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_of.h>
 #include <drm/drm_probe_helper.h>
 #include <linux/dma-mapping.h>
 #include <linux/module.h>
@@ -45,7 +46,7 @@ static int arcpgu_load(struct drm_device *drm)
 {
 	struct platform_device *pdev = to_platform_device(drm->dev);
 	struct arcpgu_drm_private *arcpgu;
-	struct device_node *encoder_node;
+	struct device_node *encoder_node = NULL, *endpoint_node = NULL;
 	struct resource *res;
 	int ret;
 
@@ -80,14 +81,23 @@ static int arcpgu_load(struct drm_device *drm)
 	if (arc_pgu_setup_crtc(drm) < 0)
 		return -ENODEV;
 
-	/* find the encoder node and initialize it */
-	encoder_node = of_parse_phandle(drm->dev->of_node, "encoder-slave", 0);
+	/*
+	 * There is only one output port inside each device. It is linked with
+	 * encoder endpoint.
+	 */
+	endpoint_node = of_graph_get_next_endpoint(pdev->dev.of_node, NULL);
+	if (endpoint_node) {
+		encoder_node = of_graph_get_remote_port_parent(endpoint_node);
+		of_node_put(endpoint_node);
+	}
+
 	if (encoder_node) {
 		ret = arcpgu_drm_hdmi_init(drm, encoder_node);
 		of_node_put(encoder_node);
 		if (ret < 0)
 			return ret;
 	} else {
+		dev_info(drm->dev, "no encoder found. Assumed virtual LCD on simulation platform\n");
 		ret = arcpgu_drm_sim_init(drm, NULL);
 		if (ret < 0)
 			return ret;