Re: [PATCH] dt-bindings: pincfg-node: Add "input-schmitt" property

[Inochi Amaoto <inochiama@xxxxxxxxxxx>]

On Mon, Jul 15, 2024 at 05:19:41PM GMT, Conor Dooley wrote:
> On Mon, Jul 15, 2024 at 05:55:28PM +0800, Inochi Amaoto wrote:
> > On Mon, Jul 15, 2024 at 11:21:25AM GMT, Krzysztof Kozlowski wrote:
> > > On 14/07/2024 13:28, Inochi Amaoto wrote:
> > > > On Sophgo CV18XX platform, threshold strength of schmitt trigger can
> > > > be configured. As this standard property is already supported by the
> > > > common pinconf code. Add "input-schmitt" property in pincfg-node.yaml
> > > > so that other platforms requiring such feature can make use of this
> > > > property.
> > > > 
> > > > Signed-off-by: Inochi Amaoto <inochiama@xxxxxxxxxxx>
> > > > ---
> > > >  Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml | 4 ++++
> > > >  1 file changed, 4 insertions(+)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml b/Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml
> > > > index d0af21a564b4..e838fcac7f2a 100644
> > > > --- a/Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml
> > > > +++ b/Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml
> > > > @@ -88,6 +88,10 @@ properties:
> > > >      description: disable input on pin (no effect on output, such as
> > > >        disabling an input buffer)
> > > > 
> > > > +  input-schmitt:
> > > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > > +    description: threshold strength for schmitt-trigger
> > > 
> > > Strength in which units? This should have proper property name suffix.
> > > 
> > 
> > I think it should be mV. Using voltage may leads to decimal.
> 
> The standard suffix for voltage is "-microvolts", so no issues with
> decimals :) And with a standard suffix, the $ref can be dropped.

Yeah, I have seen the "-microvolts", but I does not think add standard
suffix is a good idea, as "input-schmitt" is a standard pinconf attribute.

The only thing confused me is that the description of PIN_CONFIG_INPUT_SCHMITT 
in include/linux/pinctrl/pinconf-generic.h says it just uses an custom
format as argument. So I think it may keep something generic?