linux-kernel - Re: [PATCH 3/4] dt-bindings: iio: dac: add mcp4822

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Message-ID: <df75afe8-0926-6725-f7aa-f26d6a6be79f@linaro.org>
Date:   Thu, 6 Apr 2023 20:58:06 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Nicolas Frattaroli <frattaroli.nicolas@...il.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Cc:     linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] dt-bindings: iio: dac: add mcp4822

On 05/04/2023 16:17, Nicolas Frattaroli wrote:
> On Mittwoch, 5. April 2023 16:10:10 CEST Krzysztof Kozlowski wrote:
>> On 05/04/2023 16:01, Nicolas Frattaroli wrote:
>>> The MCP4801, MCP4802, MCP4811, MCP4812, MCP4821, and MCP4822 are
>>> SPI digital-to-analog converters by Microchip, which have an
>>> internal voltage reference, in contrast to the MCP49xx series
>>> of DACs which use an external voltage reference.
>>>
>>> Thus, these need a separate binding, as to not overcomplicate
>>> the mcp4922 binding.
>>
>> The difference is just one property which is very easy to handle - one
>> allOf:if:then: with
>>     vref-supply: false
>>
>> Are there any other differences?
>>
>> Best regards,
>> Krzysztof
>>
>>
> 
> In place of the external vref input, the MCP48XX series chips also
> have a "SHDN" input, which is an active-low pin to disable the whole
> chip and put it in a low power state. Future users of the bindings
> may want to model this as being tied to some GPIO, though I haven't
> done it here since I don't care about this feature.

OK to keep them separate, but then you should add here powerdown-gpios.
Bindings should be complete.

Best regards,
Krzysztof