Re: [PATCH v4 2/3] dt-bindings: hwmon: ti,ina2xx: Add ti,shunt-gain property

[Guenter Roeck <linux@roeck-us.net>]

On Tue, Nov 02, 2021 at 05:27:54AM +0000, Nathan Rossi wrote:
> From: Nathan Rossi <nathan.rossi@digi.com>
> 
> Add a property to the binding to define the selected shunt voltage gain.
> This specifies the range and accuracy that applies to the shunt circuit.
> This property only applies to devices that have a selectable shunt
> voltage range via PGA or ADCRANGE register configuration.
> 
> Signed-off-by: Nathan Rossi <nathan.rossi@digi.com>
> Reviewed-by: Rob Herring <robh@kernel.org>

Applied to hwmon-next.

Thanks,
Guenter

> ---
> Changes in v2:
> - Added binding for shunt-gain
> 
> Changes in v3:
> - Fix schema error, setting $ref to uint32
> - Improve the description to detail exactly how to define the property
>   and how the property affects initial device configuration and
>   calculation of values
> ---
>  .../devicetree/bindings/hwmon/ti,ina2xx.yaml        | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> ---
> 2.33.0
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml b/Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml
> index 180573f26c..47af97bb4c 100644
> --- a/Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml
> +++ b/Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml
> @@ -36,6 +36,27 @@ properties:
>        Shunt resistor value in micro-Ohm.
>      $ref: /schemas/types.yaml#/definitions/uint32
>  
> +  ti,shunt-gain:
> +    description: |
> +      Programmable gain divisor for the shunt voltage accuracy and range. This
> +      property only applies to devices that have configurable PGA/ADCRANGE. The
> +      gain value is used configure the gain and to convert the shunt voltage,
> +      current and power register values when reading measurements from the
> +      device.
> +
> +      For devices that have a configurable PGA (e.g. INA209, INA219, INA220),
> +      the gain value maps directly with the PG bits of the config register.
> +
> +      For devices that have ADCRANGE configuration (e.g. INA238) a shunt-gain
> +      value of 1 maps to ADCRANGE=1 where no gain divisor is applied to the
> +      shunt voltage, and a value of 4 maps to ADCRANGE=0 such that a wider
> +      voltage range is used.
> +
> +      The default value is device dependent, and is defined by the reset value
> +      of PGA/ADCRANGE in the respective configuration registers.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [1, 2, 4, 8]
> +
>  required:
>    - compatible
>    - reg