drm/fsl-dcu: handle missing panel gracefully

If the device tree property fsl,panel is missing, drm_panel_attach
is called with a NULL pointer as first argument. Having a panel is
basically mandatory since RGB is the only supported connector.
Check if a panel node has been found, return -ENODEV and cleanup
otherwise.

Signed-off-by: Stefan Agner <stefan@agner.ch>

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
index 20fb7b0..98c998d 100644 (file)
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
@@ -171,14 +171,18 @@ int fsl_dcu_drm_connector_create(struct fsl_dcu_drm_device *fsl_dev,
                                      DRM_MODE_DPMS_OFF);
 
        panel_node = of_parse_phandle(fsl_dev->np, "fsl,panel", 0);
-       if (panel_node) {
-               fsl_dev->connector.panel = of_drm_find_panel(panel_node);
-               if (!fsl_dev->connector.panel) {
-                       ret = -EPROBE_DEFER;
-                       goto err_sysfs;
-               }
-       of_node_put(panel_node);
+       if (!panel_node) {
+               dev_err(fsl_dev->dev, "fsl,panel property not found\n");
+               ret = -ENODEV;
+               goto err_sysfs;
+       }
+
+       fsl_dev->connector.panel = of_drm_find_panel(panel_node);
+       if (!fsl_dev->connector.panel) {
+               ret = -EPROBE_DEFER;
+               goto err_panel;
        }
+       of_node_put(panel_node);
 
        ret = drm_panel_attach(fsl_dev->connector.panel, connector);
        if (ret) {
@@ -188,6 +192,8 @@ int fsl_dcu_drm_connector_create(struct fsl_dcu_drm_device *fsl_dev,
 
        return 0;
 
+err_panel:
+       of_node_put(panel_node);
 err_sysfs:
        drm_connector_unregister(connector);
 err_cleanup: