Re: [PATCH 1/4] dt-bindings: iio: adc: add ti,ads122c14

[David Lechner]

On 6/16/26 11:07 AM, Conor Dooley wrote:
> On Mon, Jun 15, 2026 at 04:59:59PM -0500, David Lechner (TI) wrote:
>> Add new bindings for ti,ads122c14 and similar devices.
>>
>> This is an ADC that is primarily intended for use with temperature
>> sensors. There are a few unusual properties because of this. In
>> particular, the reference voltage source and current output requirements
>> can be different for each measurement, so these are included in the
>> channel bindings.
>>
>> The REFP/REFN reference voltage is usually just connected to a resistor
>> that is being driven by the ADC's current outputs, so there is special
>> property for this case rather than requiring a regulator to be defined
>> to represent that.
>>
>> ti,vref-source is reused from ti,tlv320adcx140.yaml (otherwise might
>> have preferred an enum of strings).
>>
>> Signed-off-by: David Lechner (TI) <dlechner@xxxxxxxxxxxx>
>> ---
>>  .../devicetree/bindings/iio/adc/ti,ads112c14.yaml  | 224 +++++++++++++++++++++
>>  MAINTAINERS                                        |   7 +
>>  include/dt-bindings/iio/adc/ti,ads112c14.h         |  11 +
>>  3 files changed, 242 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml
>> new file mode 100644
>> index 000000000000..dc7f37cad772
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml
>> @@ -0,0 +1,224 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/iio/adc/ti,ads112c14.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Texas Instruments' ADS112C14 and similar ADC chips
>> +
>> +description: |
>> +  Supports the following Texas Instruments' ADC chips:
>> +  - ADS112C14 (16-bit)
>> +  - ADS122C14 (24-bit)
>> +
>> +  https://www.ti.com/lit/ds/symlink/ads122c14.pdf
>> +
>> +  These chips are primarily designed for use with temperature sensors such as
>> +  RTDs and thermocouples. The channel bindings reflect this in that each channel
>> +  represents the conditions required to make a measurement rather than strictly
>> +  just the physical input channels.
>> +
>> +maintainers:
>> +  - David Lechner <dlechner@xxxxxxxxxxxx>
>> +
>> +unevaluatedProperties: false
> 
> Weird positioning of this.

IIRC, Rob asked that I do it in this order on another binding a while
ago (the reasoning being that it was too far away from properties:
otherwise), so I've done it like this on a few bindings now. It doesn't
make much difference to me though.

> 
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - ti,ads112c14
>> +      - ti,ads122c14
>> +
>> +  reg:
>> +    items:
>> +      - minimum: 0x40
>> +        maximum: 0x47
>> +
>> +  clocks:
>> +    maxItems: 1
>> +    description: Optional external clock connected to GPIO3 pin.
>> +
>> +  avdd-supply: true
>> +  dvdd-supply: true
>> +
>> +  refp-supply: true
>> +  refn-supply: true
>> +
>> +  refp-refn-resistor-ohms:
> 
> Missing prefix here and elsewhere.

I thought we didn't need a prefix when using standard units.


>> +      ti,vref-source:
>> +        description: |
>> +          Indicates the source for the reference voltage for this channel.
>> +          0 - Internal 2.5V reference
>> +          1 - Internal 1.25V reference
>> +          2 - External reference (REFP-REFN)
>> +          3 - AVDD as reference
> 
> My usual complaint here about things you have to make macros for, could
> these just be strings from the get-go?

As in the commit message, this is an existing property name, so I didn't want
to change the type. But I agree that strings are better for this kind of thing
so perhaps I should just use a different property name instead so we can do
it better.