Re: [PATCH RFC v2 0/3] dt-bindings: iio: adc: Add reference, excitation and burn-out properties

[David Lechner]

On 6/22/26 2:30 PM, Kurt Borja wrote:
> Hi all,
> 
> After submitting a patch series adding support for TI ADS126X ADCs [1],
> I was made aware by David [2] that at least two more chip families,
> ads1220 [3] and ads1x2c14, share very similar features (though these
> chips are not really compatible between them). After that, I found one
> more chip with the same features which is already upstream, the
> AD4170-4.
> 
> As David explained in [2], these chips are intended to be used with
> RTDs, thermocouples or other resistive sensors so they share the
> following per-channel features:
> 
>   - Configurable reference selection
>   - Burn-out Current Sources (BOCS) for diagnostic purpuses
>   - Excitation current sources (usually called IDACs TI) for sensor
>     current biasing
> 
> Given that these three features are present in all four devices and
> three of these drivers are still under review, my proposal is to have
> these features be described in adc.yaml and have this series merged
> before the three others [1] [2] [3].
> 
> This series is sent as RFC because I still don't have much experience
> with dt-bindings and I don't know if this approach or the properties are
> general enough to be described like this.

It will probably be easier if I just include these patches when I do
v2 of my series (if you don't mind me tweaking them a bit).

> 
> No dependencies between properties were provided because not all devices
> may be able to configure each one of them.
> 
> [1] https://lore.kernel.org/linux-iio/20260612-ads126x-v1-0-894c788d03ed@xxxxxxxxx/
> [2] https://lore.kernel.org/linux-iio/20260615-iio-adc-ti-ads122c14-v1-0-e6bdadf7cb2b@xxxxxxxxxxxx/
> [3] https://lore.kernel.org/linux-iio/20260610151342.44274-1-zizuzacker@xxxxxxxxx/
> 
> Signed-off-by: Kurt Borja <kuurtb@xxxxxxxxx>
> ---
> v2:
>   - reference-source is now a string-array and now presents a couple of
>     quick examples
>   - excitation-* properties now do not enforce arbitrary limits
>   - Dropped burn-out-current-polarity because it was not general enough
>   - I kept burn-out-current-microamp because the discussion around it is
>     still ongoing
> 
> v1: https://patch.msgid.link/20260618-new-channel-props-v1-0-963c1b5cf40a@xxxxxxxxx
> 
> ---
> Kurt Borja (3):
>       dt-bindings: iio: adc: Add reference-source property
>       dt-bindings: iio: adc: Add excitation current sources properties
>       dt-bindings: iio: adc: Add burn-out current properties
> 
>  Documentation/devicetree/bindings/iio/adc/adc.yaml | 38 ++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
> ---
> base-commit: a50909aa46dec46de3c73235fc15a7d6f763d996
> change-id: 20260618-new-channel-props-4fbd52020da2
>