linux-kernel - Re: [PATCH v10 1/2] dt-bindings: iio: adc: add max14001

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Message-ID: <7176887b-d406-46e4-b43a-7924c36ddb78@baylibre.com>
Date: Tue, 2 Sep 2025 10:30:47 -0500
From: David Lechner <dlechner@...libre.com>
To: Marilene Andrade Garcia <marilene.agarcia@...il.com>,
 linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
 devicetree@...r.kernel.org
Cc: Kim Seer Paller <kimseer.paller@...log.com>,
 Jonathan Cameron <jic23@...nel.org>, Nuno Sá
 <nuno.sa@...log.com>, Andy Shevchenko <andy@...nel.org>,
 Lars-Peter Clausen <lars@...afoo.de>,
 Michael Hennerich <Michael.Hennerich@...log.com>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>,
 Marcelo Schmitt <marcelo.schmitt1@...il.com>,
 Marcelo Schmitt <Marcelo.Schmitt@...log.com>,
 Ceclan Dumitru <dumitru.ceclan@...log.com>,
 Jonathan Santos <Jonathan.Santos@...log.com>,
 Dragos Bogdan <dragos.bogdan@...log.com>
Subject: Re: [PATCH v10 1/2] dt-bindings: iio: adc: add max14001

On 9/2/25 9:29 AM, David Lechner wrote:
> On 9/2/25 8:15 AM, Marilene Andrade Garcia wrote:
>> Add device-tree documentation for MAX14001/MAX14002 ADCs.
>> The MAX14001/MAX14002 are isolated, single-channel analog-to-digital
>> converters with programmable voltage comparators and inrush current
>> control optimized for configurable binary input applications.
> 
> When there are multiple devices, DT maintainers like to know
> what is the difference between the devices.
> 
>>
>> Co-developed-by: Marilene Andrade Garcia <marilene.agarcia@...il.com>
>> Signed-off-by: Marilene Andrade Garcia <marilene.agarcia@...il.com>
>> Signed-off-by: Kim Seer Paller <kimseer.paller@...log.com>
> 
> Sine the patch is From: M.A.G., according to [1], this should be:
> 
> Co-developed-by: K.S.P.
> Signed-off-by: K.S.P.
> Signed-off-by: M.A.G.
> 
> (hopefully obvious, but don't use the abbreviations - I just did
> that for brevity)
> 
> [1]: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by
> 
>> ---
>>  .../bindings/iio/adc/adi,max14001.yaml        | 79 +++++++++++++++++++
>>  MAINTAINERS                                   |  8 ++
>>  2 files changed, 87 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml b/Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
>> new file mode 100644
>> index 000000000000..ff9a41f04300
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/adi,max14001.yaml
>> @@ -0,0 +1,79 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +# Copyright 2023-2025 Analog Devices Inc.
>> +# Copyright 2023 Kim Seer Paller
>> +# Copyright 2025 Marilene Andrade Garcia
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/iio/adc/adi,max14001.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Analog Devices MAX14001-MAX14002 ADC
>> +
>> +maintainers:
>> +  - Kim Seer Paller <kimseer.paller@...log.com>
>> +  - Marilene Andrade Garcia <marilene.agarcia@...il.com>
>> +
>> +description: |
>> +    Single channel 10 bit ADC with SPI interface.
>> +    Datasheet can be found here
>> +      https://www.analog.com/media/en/technical-documentation/data-sheets/MAX14001-MAX14002.pdf
>> +
>> +$ref: /schemas/spi/spi-peripheral-props.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - adi,max14001
>> +      - adi,max14002

It looks like we could have a fallback here since it looks like
the only difference between the chips is:

	The inrush trigger threshold, current magnitude, and
	current duration are all programmable in the MAX14001
	but are fixed in the MAX14002.

Which would look like this:

    compatible:
      oneOf:
        - const: adi,max14002
        - items:
            - const: adi,max14001
            - const: adi,max14002

And

	compatible = "adi,max14001", "adi,max14002";

>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  spi-max-frequency:
>> +    maximum: 5000000

After reading the driver, I see that we should also have:

	spi-lsb-first: true

as a required property.