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

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

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Hello Conor,

On Tue, May 30, 2023 at 11:20:38PM +0100, Conor Dooley wrote:
> 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>

Thanks!

> Rob did note that gpio-hog.yaml in dt-schema would need to be updated,

This is a followup-change in a separate repository once the change
under discussion is in mainline, right?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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