mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem_res) {
dev_err(&pdev->dev, "Unable to get register resource.\n");
mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem_res) {
dev_err(&pdev->dev, "Unable to get register resource.\n");