Re: [PATCH 1/5] dt-bindings: iio: adc: Add TI ADS126x ADC family

["Kurt Borja" <kuurtb@gmail.com>]

On Sun Jun 14, 2026 at 11:34 PM -05, Krzysztof Kozlowski wrote:
> On 14/06/2026 22:53, Kurt Borja wrote:
>> Hi Krzysztof,
>> 
>> On Sat Jun 13, 2026 at 1:54 PM -05, Krzysztof Kozlowski wrote:
>>> On Fri, Jun 12, 2026 at 05:46:19PM -0500, Kurt Borja wrote:
>>>> +  ti,neg-refmux:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>>> +    description: |
>>>> +      Selects the negative voltage reference input:
>>>> +      0: Internal 2.5 V reference
>>>> +      1: AIN1 pin
>>>> +      2: AIN3 pin
>>>> +      3: AIN5 pin
>>>> +      4: AVSS pin
>>>> +    minimum: 0
>>>> +    maximum: 4
>>>> +    default: 0
>>>> +
>>>> +  ti,vbias:
>>>> +    $ref: /schemas/types.yaml#/definitions/flag
>>>> +    description: Enables the level-shift voltage on the AINCOM pin.
>>>> +    default: false
>>>
>>> There is no such syntax, drop.
>> 
>> The "default: false" syntax? Sure I'll drop.
>> 
>>>
>>>> +
>>>> +  ti,idac1-pin:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>>> +    description: |
>>>> +      Selects the analog input pin to connect IDAC1:
>>>> +      0: AIN0
>>>> +      1: AIN1
>>>> +      2: AIN2
>>>> +      3: AIN3
>>>> +      4: AIN4
>>>> +      5: AIN5
>>>> +      6: AIN6
>>>> +      7: AIN7
>>>> +      8: AIN8
>>>> +      9: AIN9
>>>> +      10: AINCOM
>>>> +      11: No Connection
>>>> +    minimum: 0
>>>> +    maximum: 11
>>>> +    default: 11
>>>> +
>>>> +  ti,idac1-microamp:
>>>> +    description: Selects the current values of IDAC1.
>>>> +    enum: [0, 50, 100, 250, 500, 750, 1000, 1500, 2000, 2500, 3000]
>>>> +    default: 0
>>>> +
>>>> +  ti,idac2-pin:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>>> +    description: |
>>>> +      Selects the analog input pin to connect IDAC2:
>>>> +      0: AIN0
>>>> +      1: AIN1
>>>> +      2: AIN2
>>>> +      3: AIN3
>>>> +      4: AIN4
>>>> +      5: AIN5
>>>> +      6: AIN6
>>>> +      7: AIN7
>>>> +      8: AIN8
>>>> +      9: AIN9
>>>> +      10: AINCOM
>>>> +      11: No Connection
>>>> +    minimum: 0
>>>> +    maximum: 11
>>>> +    default: 11
>>>> +
>>>> +  ti,idac2-microamp:
>>>> +    description: Selects the current values of IDAC2.
>>>> +    enum: [0, 50, 100, 250, 500, 750, 1000, 1500, 2000, 2500, 3000]
>>>> +    default: 0
>>>> +
>>>> +  clocks:
>>>> +    maxItems: 1
>>>> +
>>>> +  '#io-channel-cells':
>>>> +    const: 1
>>>> +
>>>> +  '#gpio-cells':
>>>> +    const: 2
>>>> +
>>>> +  gpio-controller: true
>>>> +
>>>> +  adc:
>>>> +    $ref: /schemas/iio/adc/ti,ads1263-adc2.yaml#
>>>
>>> Not a separate device node. Fold into the parent... or explain in
>>> commit msg. You have entire commit msg to explain odd things.
>>>
>>> In that binding description you call it "independent", so it should have
>>> its own SPI chip select? Why "independent" and part of this binding?
>>> Maybe not independent, so basically part of this device?
>> 
>> It's independent in the sense that it is a proper subdevice on the same
>
> You cannot use DT syntax as argument why you use DT syntax like that.

I'm not saying subdevice in the DT sense, I'm saying subdevice in the
actual secondary ADC inside the chip sense.

>
>
>> chip. It shares the serial interface but operates completely in
>> parallel.
>
> How completely in parallel? If the interface is the same, then it does
> not operate in parallel. It's impossible.

It does conversions in parallel, communication is of course still
serial.

>
>> 
>> I decided to add a subnode because other devices might request their
>> io-channels and most importantly a different voltage reference might be
>> connected to it.
>> 
>> I'll clarify this in the commmit message on the next version. Although
>> after seeing this submitted bindings [1], I wonder if it's a better
>> approach to do something like
>> 
>> 	spi@0 {
>> 		mydevice@0 {
>> 			...
>> 			adc@0 { ... };
>> 			adc@1 { ... };
>> 		};
>> 	};
>> 
>> Any thoughts?
>
> Does not look like separate subnode. You still did not provide arguments
> why this is independent.

Well, there's not more arguments than this [1].

Anyway, I'll go for David's #io-channels-cells = <2> approach and drop
the subnode.

>
> Best regards,
> Krzysztof

[1] https://lore.kernel.org/linux-iio/DJ93WSYC3HTT.3NXQW390CLQ82@gmail.com/

-- 
Thanks,
 ~ Kurt