platform_set_drvdata(pdev, data);
 
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       if (r == NULL) {
+       if (!r) {
                dev_err(&pdev->dev, "platform_get_resource failed\n");
                return -ENODEV;
        }
        data->reg_base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
-       if (data->reg_base == NULL)
+       if (!data->reg_base)
                return -ENOMEM;
 
        data->irq = platform_get_irq(pdev, 0);
        }
        data->buffer_virt = dmam_alloc_coherent(&pdev->dev,
                                COMBINED_BUFFER_SIZE, &buf_addr, GFP_KERNEL);
-       if (data->buffer_virt == NULL) {
+       if (!data->buffer_virt) {
                dev_err(&pdev->dev, "allocate buffer failed\n");
                return -ENOMEM;
        }