Re: [PATCH v4 1/2] dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04

[Kyle Hsieh]

Hi Conor,

On Wed, Aug 12, 2026 at 12:56 AM Conor Dooley <conor@xxxxxxxxxx> wrote:
>
> On Tue, Aug 11, 2026 at 10:48:37AM +0800, Kyle Hsieh wrote:
> > Add device tree binding documentation for Texas Instruments ADS112C04
> > I2C Analog-to-Digital Converters.
> >
> > These devices provide 4-channel, 16-bit delta-sigma ADCs with an I2C
> > interface, programmable gain amplifier (PGA), and data-ready (DRDY)
> > interrupt output.
> >
> > The binding uses child nodes to dynamically define the connected
> > single-ended or differential channels.
> >
> > Excitation current, burn-out current, and reference source properties
> > are also included to fully describe the chip's hardware capabilities,
> > aligned with the ti,ads112c14 binding conventions.
> >
> > Signed-off-by: Kyle Hsieh <kylehsieh1995@xxxxxxxxx>
>
> > +patternProperties:
> > +  "^channel@[0-9a-b]$":
> > +    $ref: adc.yaml
> > +    unevaluatedProperties: false
> > +    properties:
> > +      reg:
> > +        items:
> > +          - maximum: 11
> > +
> > +      single-channel:
> > +        maximum: 3
>
> Can someone explain to me please why the maximum for this is 3 when reg
> goes up to 11? What do the additional reg entries beyond 3 represent?
reg here is just an index for the channel node, not an input pin number.
The chip has 12 usable input MUX settings (8 differential pairs and 4
single-ended inputs), so at most 12 channel nodes can be described,
hence maximum 11.

single-channel refers to the physical analog input pin, and the chip
only has AIN0-AIN3, hence maximum 3.

Best regards,
Kyle Hsieh
>
> > +
> > +      diff-channels:
> > +        items:
> > +          maximum: 3
> > +
> > +      excitation-channels:
> > +        maxItems: 2
> > +        items:
> > +          maximum: 5
> > +        description:
> > +          Additionally to AIN0-AIN3, IDAC1/IDAC2 can also be routed to
> > +          REFP0 (4) and REFN0 (5).