RE: [PATCH 1/2] dt-bindings: iio: adc: ad4080: add AD4880 support
From: Miclaus, Antoniu
Date: Tue Feb 03 2026 - 10:44:32 EST
...
> > + then:
> > + properties:
> > + io-backends:
> > + minItems: 2
> > + required:
> > + - adi,aux-spi-cs
> > + else:
> > + properties:
> > + io-backends:
> > + maxItems: 1
> > +
> > additionalProperties: false
> >
> > examples:
> > @@ -98,4 +127,22 @@ examples:
> > io-backends = <&iio_backend>;
> > };
> > };
> > + - |
> > + spi {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + adc@0 {
> > + compatible = "adi,ad4880";
> > + reg = <0>;
> > + adi,aux-spi-cs = <1>;
>
> We can already have multiple reg for a multiple CS device.
>
> reg = <0>, <1>;
>
> So we shouldn't need a new adi,aux-spi-cs property for that.
Sure, that was the initial plan but for some reason going for multiple regs gets me to this:
[ 11.396833] spi_new_ancillary_device from ad4080_probe+0x4b8/0x5a4
[ 11.396861] ad4080_probe from really_probe+0xc8/0x2c8
[ 11.397281] ad4080 spi1.0: chipselect 1 already in use
[ 11.397297] ad4080 spi1.0: failed to register ancillary device
[ 11.397317] ad4080 spi1.0: probe with driver ad4080 failed with error -16
While the aux-spi-cs works fine. Any tips?
>
> > + spi-max-frequency = <10000000>;
> > + vdd33-supply = <&vdd33>;
> > + vddldo-supply = <&vddldo>;
> > + vrefin-supply = <&vrefin>;
> > + clocks = <&cnv>;
> > + clock-names = "cnv";
> > + io-backends = <&iio_backend_cha>, <&iio_backend_chb>;
> > + };
> > + };
> > ...