exynos: drm: dsi: Attach in_bridge in MIC driver

MIC drivers in the Exynos5433 display pipeline are already registered
as bridge drivers and it is more advisable to attach the downstream
bridge on the bridge attach call instead of doing the same in the
DSI driver.

This makes bridge attachment more meaningful and avoids the races
during bridge function calls.

So, move the bridge finding and drm_bridge_attach from DSI to MIC.
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220303163654.3381470-4-jagan@amarulasolutions.com

drivers/gpu/drm/exynos/exynos_drm_dsi.c

@@ -1660,11 +1660,6 @@ static int exynos_dsi_of_read_u32(const struct device_node *np,
 	return ret;
 }
 
-enum {
-	DSI_PORT_IN,
-	DSI_PORT_OUT
-};
-
 static int exynos_dsi_parse_dt(struct exynos_dsi *dsi)
 {
 	struct device *dev = dsi->dev;
@@ -1695,8 +1690,6 @@ static int exynos_dsi_bind(struct device *dev, struct device *master,
 	struct exynos_dsi *dsi = dev_get_drvdata(dev);
 	struct drm_encoder *encoder = &dsi->encoder;
 	struct drm_device *drm_dev = data;
-	struct device_node *in_bridge_node;
-	struct drm_bridge *in_bridge;
 	int ret;
 
 	drm_simple_encoder_init(drm_dev, encoder, DRM_MODE_ENCODER_TMDS);
@@ -1707,14 +1700,6 @@ static int exynos_dsi_bind(struct device *dev, struct device *master,
 	if (ret < 0)
 		return ret;
 
-	in_bridge_node = of_graph_get_remote_node(dev->of_node, DSI_PORT_IN, 0);
-	if (in_bridge_node) {
-		in_bridge = of_drm_find_bridge(in_bridge_node);
-		if (in_bridge)
-			drm_bridge_attach(encoder, in_bridge, NULL, 0);
-		of_node_put(in_bridge_node);
-	}
-
 	return mipi_dsi_host_register(&dsi->dsi_host);
 }
 

drivers/gpu/drm/exynos/exynos_drm_mic.c

@@ -102,6 +102,7 @@ struct exynos_mic {
 	struct videomode vm;
 	struct drm_encoder *encoder;
 	struct drm_bridge bridge;
+	struct drm_bridge *next_bridge;
 
 	bool enabled;
 };
@@ -298,12 +299,22 @@ static void mic_pre_enable(struct drm_bridge *bridge)
 
 static void mic_enable(struct drm_bridge *bridge) { }
 
+static int mic_attach(struct drm_bridge *bridge,
+		      enum drm_bridge_attach_flags flags)
+{
+	struct exynos_mic *mic = bridge->driver_private;
+
+	return drm_bridge_attach(bridge->encoder, mic->next_bridge,
+				 &mic->bridge, flags);
+}
+
 static const struct drm_bridge_funcs mic_bridge_funcs = {
 	.disable = mic_disable,
 	.post_disable = mic_post_disable,
 	.mode_set = mic_mode_set,
 	.pre_enable = mic_pre_enable,
 	.enable = mic_enable,
+	.attach = mic_attach,
 };
 
 static int exynos_mic_bind(struct device *dev, struct device *master,
@@ -377,6 +388,7 @@ static int exynos_mic_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct exynos_mic *mic;
+	struct device_node *remote;
 	struct resource res;
 	int ret, i;
 
@@ -420,6 +432,16 @@ static int exynos_mic_probe(struct platform_device *pdev)
 		}
 	}
 
+	remote = of_graph_get_remote_node(dev->of_node, 1, 0);
+	mic->next_bridge = of_drm_find_bridge(remote);
+	if (IS_ERR(mic->next_bridge)) {
+		DRM_DEV_ERROR(dev, "mic: Failed to find next bridge\n");
+		ret = PTR_ERR(mic->next_bridge);
+		goto err;
+	}
+
+	of_node_put(remote);
+
 	platform_set_drvdata(pdev, mic);
 
 	mic->bridge.funcs = &mic_bridge_funcs;