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Message-ID: <3163f930-fa45-4673-bc26-58fef7be49da@gmail.com>
Date: Thu, 16 May 2024 11:18:35 +0300
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Subject: Re: [PATCH 1/6] dt-bindings: adc: ad7173: add support for ad411x
To: David Lechner <dlechner@baylibre.com>, Jonathan Cameron <jic23@kernel.org>
Cc: dumitru.ceclan@analog.com, Lars-Peter Clausen <lars@metafoo.de>,
 Michael Hennerich <Michael.Hennerich@analog.com>,
 Rob Herring <robh@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>, linux-iio@vger.kernel.org,
 devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240401-ad4111-v1-0-34618a9cc502@analog.com>
 <20240401-ad4111-v1-1-34618a9cc502@analog.com>
 <CAMknhBHeKAQ45=5-dL1T1tv-mZcPN+bNo3vxWJYgWpEPE+8p3Q@mail.gmail.com>
 <25cb3514-1281-49a8-9e9b-40ead9b050dc@gmail.com>
 <CAMknhBHu8DveBgV3cor8RP2Up4Zs-+QRx7S2aoHZ_3iKiErVjg@mail.gmail.com>
 <20240406155328.447b594f@jic23-huawei>
 <64b7fd83-f226-4b1f-a801-0fe1cf20f842@gmail.com>
 <20240413114825.74e7f3fa@jic23-huawei>
 <89e93f4d-e569-46ee-802d-a1668a01b882@gmail.com>
 <20240420153310.7876cb8a@jic23-huawei>
 <CAMknhBGxEfGJhi+0Pxi+XqCSKLAKLzhLOt_rZo+vP=XqQDqWGA@mail.gmail.com>
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From: "Ceclan, Dumitru" <mitrutzceclan@gmail.com>
In-Reply-To: <CAMknhBGxEfGJhi+0Pxi+XqCSKLAKLzhLOt_rZo+vP=XqQDqWGA@mail.gmail.com>
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On 16/05/2024 00:42, David Lechner wrote:
> On Sat, Apr 20, 2024 at 9:33 AM Jonathan Cameron <jic23@kernel.org> wrote:
>>
>> On Mon, 15 Apr 2024 21:42:50 +0300
>> "Ceclan, Dumitru" <mitrutzceclan@gmail.com> wrote:
>>
>>> On 13/04/2024 13:49, Jonathan Cameron wrote:
>>>> On Tue, 9 Apr 2024 11:08:28 +0300
>>>> "Ceclan, Dumitru" <mitrutzceclan@gmail.com> wrote:
>>>>
>>>>> On 06/04/2024 17:53, Jonathan Cameron wrote:
>>>>>> On Wed, 3 Apr 2024 10:40:39 -0500
>>>>>> David Lechner <dlechner@baylibre.com> wrote:
>>>>>>
>>>>>>> On Wed, Apr 3, 2024 at 2:43 AM Ceclan, Dumitru <mitrutzceclan@gmail.com> wrote:
>>>>>>>>
>>>>>>>> On 01/04/2024 22:37, David Lechner wrote:
>>>>>>>>> On Mon, Apr 1, 2024 at 10:10 AM Dumitru Ceclan via B4 Relay
>>>>>>>>> <devnull+dumitru.ceclan.analog.com@kernel.org> wrote:
>>>>>>>>>>
>>>>>>>>>> From: Dumitru Ceclan <dumitru.ceclan@analog.com>
>>>>>>>>
>>> ...
>>>>>
>>>>>>>> Other alternative that came to my mind: attribute "adi,current-channel".
>>>>>>>
>>>>>>> Having a boolean flag like this would make more sense to me if we
>>>>>>> don't agree that the suggestion below is simpler.
>>>>>>>
>>>
>>> ...
>>>
>>>>
>>>> We do directly relate reg to channel numbers in drivers like the ad7292 (where not
>>>> all channels are differential)  I'm not convinced either way on what is best
>>>> here where reg is currently just an index into a channel specification, not
>>>> meaningful for which pins are involved.
>>>>
>>>> It doesn't seem worth adding an equivalent of diff-channels for a single channel
>>>> setup but I guess it would be more consistent.
>>>>
>>>
>>> Would you agree with the attribute adi,current-channel within the channel and
>>>  diff-channels set to the correspondent current inputs (13 10 for pair IN2)?
>>
>> From another thread today I've concluded we do need a single-channel
>> equivalent of diff-channels, but you are right that here it is a differential
>> channel so <13 10> seems like the best option to me.
>>
> 
> Current inputs are differential? It seems like we would need 4 input
> pins for that.
We cannot measure differential current channels.
We are measuring a voltage differential channel of the voltage drop across
the shunt resistor. Differential in the sense that inputs 13 and 10 are
routed to the ADC.