Re: [PATCH v1 1/2] dt-bindings: iio: adc: avia-hx711: add avia,hx710b compatible

[Andreas Klinger <ak@it-klinger.de>]

Hi,

David Lechner <dlechner@baylibre.com> schrieb am Sa, 18. Apr 16:46:
> On 4/18/26 12:05 PM, Piyush Patle wrote:

[...]

> >  
> >    Specifications about the driver can be found at:
> >    http://www.aviaic.com/ENProducts.aspx
> > @@ -23,11 +33,12 @@ properties:
> >    compatible:
> >      enum:
> >        - avia,hx711
> > +      - avia,hx710b
> >  
> >    sck-gpios:
> >      description:
> >        Definition of the GPIO for the clock (output). In the datasheet it is
> > -      named PD_SCK
> > +      named PD_SCK.
> 
> Save the cleanups for a separate patch to keep the adding HX710B changes clear.
> 
> I'm guessing the existing binding for HX711 is quite old because it is quite
> incomplete.
> 
> It has avdd-supply, but is missing vsup-supply and dvdd-supply.
> 
> It should probably also have a way to describe how the rate pin is wired.
> 
> And it should have a clocks property instead of clock-frequency.

The real meaning is a wait time until the DOUT is stable. As a submitted the
driver many years ago my suggestion of a wait time property was not accepted
because it would have introduced a new property which didn't exit in those days.
The suggestion was to name it clock-frequency because it already existed. This
clock-frequency made the driver also a little bit more complicated because at
the end we needed a waiting time and not a frequency.

Today i see there is as "wait-delay" property already introduced at other
bindings. This would also simplify the driver a bit.

@robh@kernel.org, @krzk+dt@kernel.org, @conor+dt@kernel.org:
Would this change in the binding be acceptable?

If yes, i could prepare a driver and binding patch separate of this patchset to
clean it up.

> It would make sense to have two clocks, on for XI/XO and one for PD_SCK.
> The second one being optional because of sck-gpios.
> 
> HX710B has many fewer pins, so we will need an:
> 
> allOf:
>   - if:
>       properties:
> 	compatible:
> 	  const: avia,hx710b
> 
> section that sets anything for pins that chip doesn't have to false, like
> vsup-supply.
> 
> HX710B also has a vref-supply that HX711 doesn't have. (Unless these are the
> same thing by a different name?)
> 
> 
> >      maxItems: 1
> >  
> >    dout-gpios:
> > @@ -43,6 +54,9 @@ properties:
> >        Definition of the regulator used as analog supply
> >  
> >    clock-frequency:
> > +    description:
> > +      Bit-bang clock frequency on PD_SCK. Keep the PD_SCK high time below
> > +      the chip power-down threshold.
> 
> I suspect that this was meant to be the crystal frequency (XI/XO), not PD_SCK
> since sck-gpios already exists for PD_SCK

see above

[...]

Best regards,

Andreas

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