Hi Vincent, thanks for the patch!

Including Bartosz who is kind of default maintainer for this component.

On Wed, Sep 5, 2018 at 3:26 PM Vincent Whitchurch
[off-list ref] wrote:

This is a dummy GPIO controller which can be used in place of the real
hardware GPIO controller (for example, an external GPIO expander) before
actual hardware is available.

Signed-off-by: Vincent Whitchurch <redacted>

This looks generally helpful. I don't know what the DT maintainers
think, but I am positive, I think rapid prototyping is a valid usecase.
We used to have the driver for testing only but this usecase is
just as valid.

+Required properties:
+- compatible: Should contain "gpio-mockup"
+- gpio-controller : Marks the device node as a gpio controller.
+- #gpio-cells : Should be two.  The first cell is the pin number and
+  the second cell is used to specify the gpio polarity:
+      0 = active high
+      1 = active low
+- nr-gpios: The number of dummy GPIOs

For this there is a standardized binding "ngpios" in gpio.txt
so just use that and reference gpio.txt please.

Yours,
Linus Walleij