drm/etnaviv: Check for platform_device_register_simple() failure

platform_device_register_simple() may fail, so we should better
check its return value and propagate it in the case of error.

Cc: <stable@vger.kernel.org>
Fixes: 246774d ("drm/etnaviv: remove the need for a gpu-subsystem DT node")
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_drv.c

@@ -631,8 +631,11 @@ static struct platform_driver etnaviv_platform_driver = {
 	},
 };
 
+static struct platform_device *etnaviv_drm;
+
 static int __init etnaviv_init(void)
 {
+	struct platform_device *pdev;
 	int ret;
 	struct device_node *np;
 
@@ -644,7 +647,7 @@ static int __init etnaviv_init(void)
 
 	ret = platform_driver_register(&etnaviv_platform_driver);
 	if (ret != 0)
-		platform_driver_unregister(&etnaviv_gpu_driver);
+		goto unregister_gpu_driver;
 
 	/*
 	 * If the DT contains at least one available GPU device, instantiate
@@ -653,12 +656,24 @@ static int __init etnaviv_init(void)
 	for_each_compatible_node(np, NULL, "vivante,gc") {
 		if (!of_device_is_available(np))
 			continue;
-
-		platform_device_register_simple("etnaviv", -1, NULL, 0);
+		pdev = platform_device_register_simple("etnaviv", -1,
+						       NULL, 0);
+		if (IS_ERR(pdev)) {
+			ret = PTR_ERR(pdev);
+			of_node_put(np);
+			goto unregister_platform_driver;
+		}
+		etnaviv_drm = pdev;
 		of_node_put(np);
 		break;
 	}
 
+	return 0;
+
+unregister_platform_driver:
+	platform_driver_unregister(&etnaviv_platform_driver);
+unregister_gpu_driver:
+	platform_driver_unregister(&etnaviv_gpu_driver);
 	return ret;
 }
 module_init(etnaviv_init);