Re: [PATCH v2 1/7] dt-bindings: iio: adc: Add TI ADS126x ADC family

[David Lechner <dlechner@baylibre.com>]

On 6/28/26 2:12 PM, Kurt Borja wrote:
> On Sun Jun 28, 2026 at 10:45 AM -05, David Lechner wrote:
>> On 6/28/26 12:36 AM, Kurt Borja wrote:
>>> The ADS1262 and ADS1263 are 32-bit, 38.4-kSPS delta-sigma ADCs with an
>>> integrated PGA, internal reference, excitation and burn-out current
>>> sources for sensor biasing and diagnostics. The ADS1263 adds a second,
>>> 24-bit delta-sigma ADC (ADC2) for background measurements.
>>>

...

>>> +
>>> +patternProperties:
>>> +  "^channel@[0-9]+$":
>>> +    $ref: /schemas/iio/adc/adc.yaml#
>>> +    unevaluatedProperties: false
>>> +
>>> +    properties:
>>> +      reg:
>>> +        maxItems: 1
>>> +
>>
>> If we want to allow single-ended/pseudo-differential inputs, then we should
>> also allow single-channel (positive pin) and common-mode-channel (negative
>> pin) properties.
>>
>> This will also require additional common-mode-<N>-supply properties to allow
>> for the negative pin connected to something other than GND.
> 
> Ah interesting. Why the N though? wouldn't a single supply connected to
> AINCOM be enough here?

In theory, any AINx could be a common mode input by connecting it to
a constant voltage supply.

>>> +        $ref: /schemas/types.yaml#/definitions/flag
>>> +        description:
>>> +          Automatically swap the IDAC1 and IDAC2 connections of alternate
>>> +          conversions. The ADC averages the alternate conversions to eliminate
>>> +          IDAC mismatch.
>>> +
>>> +      ti,pga-bypass:
>>> +        $ref: /schemas/types.yaml#/definitions/flag
>>> +        description: Bypass the Programmable Gain Amplifier (PGA).
>>
>> Why would this need to be a DT property? I didn't read this datasheet
>> too much, but in other chips I have seen there are usually rules that
>> PGA has to be bypassed under certain conditions, but not others, so
>> this seems like something for the driver to handle rather than the
>> devicetree.
> 
> To be honest, I don't know what would be the application for this. AFAIK
> when the PGA is bypassed the analog inputs are read unbuffered (?) In
> that case shouldn't this belong DT?
> 

Let's leave it out of the DT for now until we learn more about how it
is intended to be used.