Re: [PATCH RFC] dt-bindings: gpio: introduce hog properties with less ambiguity

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Thu, Jul 9, 2020 at 8:39 AM Uwe Kleine-König <uwe@xxxxxxxxxxxxxxxxx> wrote:

> From: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
>
> For active low lines the semantic of output-low and output-high is hard
> to grasp because there is a double negation involved and so output-low
> is actually a request to drive the line high (aka inactive).
>
> So introduce output-inactive and output-active with the same semantic as
> output-low and output-high have respectively today, but with a more
> sensible name.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
> Hello,
>
> no code changes yet. Just asking for feedback if you consider this
> sensible.

It makes sense, and it is in line with earlier inversion problems that
people have had.

Could you use the properties:
output-asserted
output-deasserted
?

(The anglo-saxon can maybe comment on whether it should be
"deasserted" or "unasserted", sorry for bikeshedding.)

This was the terminology we discussed wrt changing the prototypes
of gpiod_set_value() from:

void gpiod_set_value(struct gpio_desc *desc, int value);

to:

void gpiod_set_value(struct gpio_desc *desc, bool asserted);

This latter simple semantic change over the entire kernel is
something "someone should do" possibly with a script or
Cocinelle.

Yours,
Linus Walleij