drm/atmel-hlcdc: Fix output initialization

drm_of_find_panel_or_bridge() is expecting np to point to the encoder
node, not the bridge or panel this encoder is feeding.
Moreover, the endpoint parameter passed to drm_of_find_panel_or_bridge()
is always set to zero, which prevents us from probing all outputs.

We also move the atmel_hlcdc_rgb_output allocation after the
panel/bridge detection to avoid useless allocations.
Reported-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Fixes: ebc94461 ("drm: convert drivers to use drm_of_find_panel_or_bridge")
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1495110921-4032-1-git-send-email-boris.brezillon@free-electrons.com

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c

@@ -152,8 +152,7 @@ static const struct drm_connector_funcs atmel_hlcdc_panel_connector_funcs = {
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };
 
-static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
-				       const struct device_node *np)
+static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
 {
 	struct atmel_hlcdc_dc *dc = dev->dev_private;
 	struct atmel_hlcdc_rgb_output *output;
@@ -161,6 +160,11 @@ static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
 	struct drm_bridge *bridge;
 	int ret;
 
+	ret = drm_of_find_panel_or_bridge(dev->dev->of_node, 0, endpoint,
+					  &panel, &bridge);
+	if (ret)
+		return ret;
+
 	output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
 	if (!output)
 		return -EINVAL;
@@ -177,10 +181,6 @@ static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
 
 	output->encoder.possible_crtcs = 0x1;
 
-	ret = drm_of_find_panel_or_bridge(np, 0, 0, &panel, &bridge);
-	if (ret)
-		return ret;
-
 	if (panel) {
 		output->connector.dpms = DRM_MODE_DPMS_OFF;
 		output->connector.polled = DRM_CONNECTOR_POLL_CONNECT;
@@ -220,22 +220,14 @@ static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
 
 int atmel_hlcdc_create_outputs(struct drm_device *dev)
 {
-	struct device_node *remote;
-	int ret = -ENODEV;
-	int endpoint = 0;
-
-	while (true) {
-		/* Loop thru possible multiple connections to the output */
-		remote = of_graph_get_remote_node(dev->dev->of_node, 0,
-						  endpoint++);
-		if (!remote)
-			break;
-
-		ret = atmel_hlcdc_attach_endpoint(dev, remote);
-		of_node_put(remote);
-		if (ret)
-			return ret;
-	}
+	int endpoint, ret = 0;
+
+	for (endpoint = 0; !ret; endpoint++)
+		ret = atmel_hlcdc_attach_endpoint(dev, endpoint);
+
+	/* At least one device was successfully attached.*/
+	if (ret == -ENODEV && endpoint)
+		return 0;
 
 	return ret;
 }