From: Angelo Dureghello <adureghello@baylibre.com>

Add gain calibration support by a per-channel resistor value.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
index 29f12d650442b8ff2eb455306ce59a0e87867ddd..df30545fb52c89a814257443183303775a06a7f2 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
@@ -204,6 +204,15 @@ patternProperties:
           considered a bipolar differential channel. Otherwise it is bipolar
           single-ended.
 
+      adi,rfilter-ohms:
+        description:
+          For ADCs that supports gain calibration, this property must be set to
+          the value of the external RFilter resistor. Proper gain error
+          correction is applied based on this value.
+        default: 0
+        minimum: 0
+        maximum: 65536
+
     required:
       - reg
       - bipolar
@@ -271,6 +280,10 @@ allOf:
     then:
       properties:
         adi,sw-mode: false
+      patternProperties:
+        "^channel@[0-9a-f]+$":
+          properties:
+            adi,rfilter-ohms: false
     else:
       properties:
         pwms:
@@ -398,6 +411,7 @@ examples:
                 reg = <8>;
                 diff-channels = <8 8>;
                 bipolar;
+                adi,rfilter-ohms = <2048>;
             };
 
         };

-- 
2.49.0

On 4/29/25 8:06 AM, Angelo Dureghello wrote:
> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Add gain calibration support by a per-channel resistor value.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> ---
>  Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
> index 29f12d650442b8ff2eb455306ce59a0e87867ddd..df30545fb52c89a814257443183303775a06a7f2 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
> @@ -204,6 +204,15 @@ patternProperties:
>            considered a bipolar differential channel. Otherwise it is bipolar
>            single-ended.
>  
> +      adi,rfilter-ohms:
> +        description:
> +          For ADCs that supports gain calibration, this property must be set to
> +          the value of the external RFilter resistor. Proper gain error
> +          correction is applied based on this value.
> +        default: 0
> +        minimum: 0
> +        maximum: 65536
> +
>      required:
>        - reg
>        - bipolar
> @@ -271,6 +280,10 @@ allOf:
>      then:
>        properties:
>          adi,sw-mode: false
> +      patternProperties:
> +        "^channel@[0-9a-f]+$":
> +          properties:
> +            adi,rfilter-ohms: false

I think this is in the wrong place. It would allow this property on ad7616, but
ad7616 does not have this feature.


>      else:
>        properties:
>          pwms:
> @@ -398,6 +411,7 @@ examples:
>                  reg = <8>;
>                  diff-channels = <8 8>;
>                  bipolar;
> +                adi,rfilter-ohms = <2048>;
>              };
>  
>          };
>

On 29.04.2025 10:26, David Lechner wrote:
> On 4/29/25 8:06 AM, Angelo Dureghello wrote:
> > From: Angelo Dureghello <adureghello@baylibre.com>
> > 
> > Add gain calibration support by a per-channel resistor value.
> > 
> > Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> > ---
> >  Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
> > index 29f12d650442b8ff2eb455306ce59a0e87867ddd..df30545fb52c89a814257443183303775a06a7f2 100644
> > --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
> > +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml
> > @@ -204,6 +204,15 @@ patternProperties:
> >            considered a bipolar differential channel. Otherwise it is bipolar
> >            single-ended.
> >  
> > +      adi,rfilter-ohms:
> > +        description:
> > +          For ADCs that supports gain calibration, this property must be set to
> > +          the value of the external RFilter resistor. Proper gain error
> > +          correction is applied based on this value.
> > +        default: 0
> > +        minimum: 0
> > +        maximum: 65536
> > +
> >      required:
> >        - reg
> >        - bipolar
> > @@ -271,6 +280,10 @@ allOf:
> >      then:
> >        properties:
> >          adi,sw-mode: false
> > +      patternProperties:
> > +        "^channel@[0-9a-f]+$":
> > +          properties:
> > +            adi,rfilter-ohms: false
> 
> I think this is in the wrong place. It would allow this property on ad7616, but
> ad7616 does not have this feature.
>

Looks like it cannot work on ad7616 due to

  - if:
      not:
        properties:
          compatible:
            enum:
              - adi,ad7606c-16
              - adi,ad7606c-18
    then:
      patternProperties:
        "^channel@[1-8]$": false


But maybe an additional patch should be added to add also adi,ad7606b
to the above enum.

Regards,
angelo


 
> 
> >      else:
> >        properties:
> >          pwms:
> > @@ -398,6 +411,7 @@ examples:
> >                  reg = <8>;
> >                  diff-channels = <8 8>;
> >                  bipolar;
> > +                adi,rfilter-ohms = <2048>;
> >              };
> >  
> >          };
> > 
>

On Tue, Apr 29, 2025 at 03:06:48PM +0200, Angelo Dureghello wrote:
> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Add gain calibration support by a per-channel resistor value.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>

Acked-by: Conor Dooley <conor.dooley@microchip.com>