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Date: Thu, 15 Feb 2024 14:13:38 +0200
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Subject: Re: [PATCH v3 4/5] dt-bindings: iio: adc: ad7192: Add AD7194 support
To: Conor Dooley <conor@kernel.org>
Cc: alexandru.tachici@analog.com, alisa.roman@analog.com,
 conor+dt@kernel.org, devicetree@vger.kernel.org, dlechner@baylibre.com,
 jic23@kernel.org, krzysztof.kozlowski+dt@linaro.org,
 krzysztof.kozlowski@linaro.org, lars@metafoo.de, linux-iio@vger.kernel.org,
 linux-kernel@vger.kernel.org, michael.hennerich@analog.com,
 robh+dt@kernel.org
References: <20240208172459.280189-1-alisa.roman@analog.com>
 <20240208172459.280189-5-alisa.roman@analog.com>
 <20240208-occupancy-shudder-514d8569e261@spud>
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From: Alisa-Dariana Roman <alisadariana@gmail.com>
In-Reply-To: <20240208-occupancy-shudder-514d8569e261@spud>
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On 08.02.2024 20:03, Conor Dooley wrote:
> Hey,
> 
> On Thu, Feb 08, 2024 at 07:24:58PM +0200, Alisa-Dariana Roman wrote:
> 
>> +patternProperties:
>> +  "^channel@([0-7a-f])$":
>> +    type: object
>> +    $ref: adc.yaml
>> +    unevaluatedProperties: false
>> +
>> +    properties:
>> +      reg:
>> +        description: The channel index.
>> +        minimum: 0
>> +        maximum: 7
> 
> There are only 8 possible channels, at indices 0 to 7, so why is the
> pattern property more permissive than that? Shouldn't "^channel@[0-7]$"
> suffice?
> 
>> +
>> +       diff-channels:
> 
>> +        description: |
>> +          The differential channel pair for Ad7194 configurable channels. The
>> +          first channel is the positive input, the second channel is the
>> +          negative input.
> 
> This duplicates the description in adc.yaml
> 
>> +        items:
>> +          minimum: 1
>> +          maximum: 16
> 
> Hmm, this makes me wonder: why doesn't this match the number of channels
> available and why is 0 not a valid channel for differential measurements?
> 
> Thanks,
> Conor.

Hello and thank you for the feedback!

I will change the pattern property and the description.

Regarding the channels, I followed the existing style of the driver for 
the AD7194 channels: one iio channel for each pseudo-differential input 
channel(AINx - AINCOM), summing up to 16 channels; and one iio channel 
for each differential channel (AINx - AINy), summing up to 8 channels. 
For the diff-channels, I thought the possible values should be 1->16 
corresponding to AIN1->AIN16 (I will add this to the description as 
suggested by David).

Kind regards,
Alisa-Dariana Roman