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Date:   Tue, 26 Jul 2022 11:47:10 +0200
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Subject: Re: [PATCH v2 2/2] spi: npcm-pspi: Add NPCM845 peripheral SPI support
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To:     Tomer Maimon <tmaimon77@gmail.com>, Mark Brown <broonie@kernel.org>
Cc:     Avi Fishman <avifishman70@gmail.com>,
        Tali Perry <tali.perry1@gmail.com>,
        Joel Stanley <joel@jms.id.au>,
        Patrick Venture <venture@google.com>,
        Nancy Yuen <yuenn@google.com>,
        Benjamin Fair <benjaminfair@google.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        OpenBMC Maillist <openbmc@lists.ozlabs.org>,
        linux-spi@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <CAP6Zq1iRowFv4qg=AqdVmBRRx5p4-5AaC1G-aZs=2LnOAOELXA@mail.gmail.com>
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On 24/07/2022 10:44, Tomer Maimon wrote:
> Hi Mark and Krzysztof,
> 
> Thanks for your reply,
> 
> On Fri, 22 Jul 2022 at 21:57, Mark Brown <broonie@kernel.org> wrote:
>>
>> On Fri, Jul 22, 2022 at 08:47:24PM +0200, Krzysztof Kozlowski wrote:
>>> On 22/07/2022 20:43, Mark Brown wrote:
>>
>>>> ...with a fallback list required by the bindings so the driver actually
>>>> binds.  Note that bindings are currently not in YAML format so there'd
>>>> be even less enforcement of that than normal, and as they're currently
>>>> written the bindings don't require fallback.
>>
>>> Yes, the bindings document should be rephrased but we were living like
>>> that for few years. :)
>>
>> The binding document as it stands only has one compatible, there's no
>> existing problem with it other than the YAML conversion.  If we're
>> adding something new that requires a fallback we should be explicit
>> about that rather than have something that's actively misleading where
>> previously things were clear.  I don't mind if we add the compatible to
>> the driver or document the requirement for the fallback but we should do
>> one of the two.
> 
> is V2 good enough? adding the compatible to the driver and the document?
> Or should we use fallback?
> If fallback is choosen, can you explain how I should do it?

I propose to use fallback. The preferred way is to convert it to DT
schema and then add new device support (so two commits). Other
acceptable way is to rephrase the TXT so it clearly states desired
compatibles - one for old device, two for new devices. There are plenty
of examples in current sources.


Best regards,
Krzysztof