drm/exynos: dp: support drm_bridge

Modify driver to support drm_bridge.

Signed-off-by: Ajay Kumar <[e-mail]>
Signed-off-by: Inki Dae <[e-mail]>
Tested-by: Rahul Sharma <[e-mail]>
Tested-by: Javier Martinez Canillas <[e-mail]>
Tested-by: Gustavo Padovan <[e-mail]>
Tested-by: Sjoerd Simons <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

Documentation/devicetree/bindings/video/exynos_dp.txt

···
 		Hotplug detect GPIO.
 			Indicates which GPIO should be used for hotplug
 			detection
+	-video interfaces: Device node can contain video interface port
+			    nodes according to [1].
+
+[1]: Documentation/devicetree/bindings/media/video-interfaces.txt
 
 Example:
 
···
 				vback-porch = <10>;
 				vfront-porch = <12>;
 				vsync-len = <6>;
+			};
+		};
+
+		ports {
+			port@0 {
+				dp_out: endpoint {
+					remote-endpoint = <&bridge_in>;
+				};
 			};
 		};
 	};

drivers/gpu/drm/exynos/exynos_dp_core.c

···
 #include <linux/interrupt.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
+#include <linux/of_graph.h>
 #include <linux/gpio.h>
 #include <linux/component.h>
 #include <linux/phy/phy.h>
···
 };
 
 /* returns the number of bridges attached */
-static int exynos_drm_attach_lcd_bridge(struct drm_device *dev,
+static int exynos_drm_attach_lcd_bridge(struct exynos_dp_device *dp,
 		struct drm_encoder *encoder)
 {
+	int ret;
+
+	encoder->bridge = dp->bridge;
+	dp->bridge->encoder = encoder;
+	ret = drm_bridge_attach(encoder->dev, dp->bridge);
+	if (ret) {
+		DRM_ERROR("Failed to attach bridge to drm\n");
+		return ret;
+	}
+
 	return 0;
 }
 
···
 	dp->encoder = encoder;
 
 	/* Pre-empt DP connector creation if there's a bridge */
-	ret = exynos_drm_attach_lcd_bridge(dp->drm_dev, encoder);
-	if (ret)
-		return 0;
+	if (dp->bridge) {
+		ret = exynos_drm_attach_lcd_bridge(dp, encoder);
+		if (!ret)
+			return 0;
+	}
 
 	connector->polled = DRM_CONNECTOR_POLL_HPD;
 
···
 		}
 	}
 
-	if (!dp->panel) {
+	if (!dp->panel && !dp->bridge) {
 		ret = exynos_dp_dt_parse_panel(dp);
 		if (ret)
 			return ret;
···
 static int exynos_dp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	struct device_node *panel_node;
+	struct device_node *panel_node, *bridge_node, *endpoint;
 	struct exynos_dp_device *dp;
 	int ret;
 
···
 		dp->panel = of_drm_find_panel(panel_node);
 		of_node_put(panel_node);
 		if (!dp->panel)
+			return -EPROBE_DEFER;
+	}
+
+	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->bridge = of_drm_find_bridge(bridge_node);
+			of_node_put(bridge_node);
+			if (!dp->bridge)
+				return -EPROBE_DEFER;
+		} else
 			return -EPROBE_DEFER;
 	}
 

drivers/gpu/drm/exynos/exynos_dp_core.h

···
 	struct drm_connector	connector;
 	struct drm_encoder	*encoder;
 	struct drm_panel	*panel;
+	struct drm_bridge	*bridge;
 	struct clk		*clock;
 	unsigned int		irq;
 	void __iomem		*reg_base;