2018-09-06 12:16 GMT+02:00 Linus Walleij [off-list ref]:

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:

quoted

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.

quoted

+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

Do we even need DT bindings for this? Device tree bindings mean that
we commit to a stable interface so that once a device with given DT
blob is released, it will work on every future kernel. Also: DT should
only include information about actual HW, not operating system
concepts. Meanwhile this is for testing purposes only and it won't end
up in any actual DT source file upstream.

I like the feature, just don't think this needs a binding document. I
will review the other patch later today.

Also: if you want to get a DT bindings patch merged, you need an Ack
from Rob Herring (Cc'ed now). You'll probably need to resend anyway as
patchwork won't pick up my Cc here.

Best regards,
Bartosz Golaszewski