return -EINVAL;
        }
 
-       up = kzalloc(sizeof(struct ar933x_uart_port), GFP_KERNEL);
+       up = devm_kzalloc(&pdev->dev, sizeof(struct ar933x_uart_port),
+                         GFP_KERNEL);
        if (!up)
                return -ENOMEM;
 
        port = &up->port;
-       port->mapbase = mem_res->start;
 
-       port->membase = ioremap(mem_res->start, AR933X_UART_REGS_SIZE);
-       if (!port->membase) {
-               ret = -ENOMEM;
-               goto err_free_up;
-       }
+       port->membase = devm_ioremap_resource(&pdev->dev, mem_res);
+       if (IS_ERR(port->membase))
+               return PTR_ERR(port->membase);
 
+       port->mapbase = mem_res->start;
        port->line = id;
        port->irq = irq_res->start;
        port->dev = &pdev->dev;
 
        ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
        if (ret)
-               goto err_unmap;
+               return ret;
 
        platform_set_drvdata(pdev, up);
        return 0;
-
-err_unmap:
-       iounmap(up->port.membase);
-err_free_up:
-       kfree(up);
-       return ret;
 }
 
 static int ar933x_uart_remove(struct platform_device *pdev)
 
        up = platform_get_drvdata(pdev);
 
-       if (up) {
+       if (up)
                uart_remove_one_port(&ar933x_uart_driver, &up->port);
-               iounmap(up->port.membase);
-               kfree(up);
-       }
 
        return 0;
 }