On Mon, 24 Apr 2023 11:23:12 +0200
Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx> wrote:
> Although this property is used right now for IIO_CHAN_INFO_SCALE,
> this ADC has two internal reference voltages, which the driver currently
> doesn't make use of.
>
> Fixes: db73419d8c06 ("dt-bindings: iio: adc: Add binding documentation for NXP IMX8QXP ADC")
> Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
Interesting that we are talking her only about vrefh, what about vrefp?
I guess the assumption is that will be wired to 0V?
The first reference I found didn't seem to imply that was necessarily the
case. https://www.mouser.com/pdfDocs/IMX8QXPAEC.pdf
Jonathan
> ---
> Thanks for your inputs. This improved descritpion should make it clear
> that this property is only about the external reference voltage, not
> about the optional, internal voltages.
>
> Changes in v2:
> * Improved commit message subject as suggested
> * Add hint about feature flag regarding multiple, internal, reference
> voltages
>
> .../devicetree/bindings/iio/adc/nxp,imx8qxp-adc.yaml | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/nxp,imx8qxp-adc.yaml b/Documentation/devicetree/bindings/iio/adc/nxp,imx8qxp-adc.yaml
> index 63369ba388e4..878e67054d7c 100644
> --- a/Documentation/devicetree/bindings/iio/adc/nxp,imx8qxp-adc.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/nxp,imx8qxp-adc.yaml
> @@ -39,6 +39,12 @@ properties:
> power-domains:
> maxItems: 1
>
> + vref-supply:
> + description: |
> + External ADC reference voltage supply on VREFH pad. If VERID[MVI] is
> + set, there are additional, internal reference voltages selectable.
> + VREFH1 is always from VREFH pad.
> +
> "#io-channel-cells":
> const: 1
>
> @@ -72,6 +78,7 @@ examples:
> assigned-clocks = <&clk IMX_SC_R_ADC_0>;
> assigned-clock-rates = <24000000>;
> power-domains = <&pd IMX_SC_R_ADC_0>;
> + vref-supply = <®_1v8>;
> #io-channel-cells = <1>;
> };
> };
