On Fri, Jun 2, 2017 at 10:28 AM, Jan Kiszka [off-list ref] wrote:

On the SIMATIC, IOT2040 only a single pin is exportable as GPIO, the
rest is required to operate the UART. To allow modeling this case,
expand the platform device data structure to specify a (consecutive) pin
subset for exporting by the gpio-exar driver.

+       if (device_property_read_u32(&pdev->dev, "gpio-exar,first-pin",
+                                    &first_pin) < 0 ||
+           device_property_read_u32(&pdev->dev, "ngpios", &ngpios) < 0)
+               return -EINVAL;

You shadow an error.

Please use
ret = device_property_...;
if (ret)
 return ret;

ret = ...
...

Moreover, I missed how you named first property, I would go rather
with "linux," prefix to show that is _internal_ / Linux only property.

Perhaps something like "linux,first-pin" ?

-- 
With Best Regards,
Andy Shevchenko