Re: [PATCH 1/2] dt-bindings: gpio: introduce hog properties with less ambiguity

[Rob Herring <robh@xxxxxxxxxx>]

On Mon, May 03, 2021 at 11:05:26PM +0200, Uwe Kleine-König wrote:
> 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 respectively have today, but with a more
> sensible name.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
> Hello,
> 
> I already sent this patch back in July and Linus (Walleij) liked the
> patch but asked for an implementation. For that I added the second patch
> now.
> 
> Best regards
> Uwe
> 
>  Documentation/devicetree/bindings/gpio/gpio.txt | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)

The schema in dtschema will need to be updated too. Really, probably all 
or most of gpio.txt needs to be moved there if not already. But for now,

Acked-by: Rob Herring <robh@xxxxxxxxxx>

> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt
> index a8895d339bfe..1061c346a619 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio.txt
> +++ b/Documentation/devicetree/bindings/gpio/gpio.txt
> @@ -196,11 +196,16 @@ Only one of the following properties scanned in the order shown below.
>  This means that when multiple properties are present they will be searched
>  in the order presented below and the first match is taken as the intended
>  configuration.
> -- input:      A property specifying to set the GPIO direction as input.
> -- output-low  A property specifying to set the GPIO direction as output with
> -	      the value low.
> -- output-high A property specifying to set the GPIO direction as output with
> -	      the value high.
> +- input:             A property specifying to set the GPIO direction as input.
> +- output-deasserted: A property specifying to set the GPIO direction as output
> +		     with the inactive value (depending on the line's polarity,
> +		     which is active-high by default)
> +- output-asserted:   A property specifying to set the GPIO direction as output
> +		     with the active value.
> +
> +For backwards compatibility "output-low" and "output-high" should be supported
> +as aliases for "output-deasserted" and "output-asserted" respectively. Their
> +usage is misleading for active-low outputs, so their use is discouraged.
>  
>  Optional properties:
>  - line-name:  The GPIO label name. If not present the node name is used.
> -- 
> 2.30.2
>