Re: [PATCH v2 1/2] dt-bindings: gpio: introduce hog properties with less ambiguity

[Conor Dooley <conor@kernel.org>]

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Hey Uwe,

On Tue, May 30, 2023 at 05:19:45PM +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@pengutronix.de>
> ---
>  Documentation/devicetree/bindings/gpio/gpio.txt | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt
> index d82c32217fff..2f037bbd3ffa 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio.txt
> +++ b/Documentation/devicetree/bindings/gpio/gpio.txt
> @@ -209,15 +209,21 @@ Required properties:
>  - gpios:      Store the GPIO information (id, flags, ...) for each GPIO to
>  	      affect. Shall contain an integer multiple of the number of cells
>  	      specified in its parent node (GPIO controller node).
> +
>  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-inactive:   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-active:     A property specifying to set the GPIO direction as output
> +		     with the active value.
> +
> +For backwards compatibility "output-low" and "output-high" are supported as
> +aliases for "output-inactive" and "output-active" respectively. Their usage is
> +misleading for active-low outputs, so their use is discouraged.

Seems like an improvement to me,
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Rob did note that gpio-hog.yaml in dt-schema would need to be updated,
but he's not around right now to approve anything there.

Cheers,
Conor.

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