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Date:   Tue, 20 Sep 2022 13:16:48 +0200
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Subject: Re: [PATCH v6 1/4 RESEND] ARM: dts: qcom: Use new compatibles for
 crypto nodes
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To:     Bhupesh Sharma <bhupesh.sharma@linaro.org>
Cc:     linux-arm-kernel@lists.infradead.org,
        linux-arm-msm@vger.kernel.org, agross@kernel.org,
        linux-kernel@vger.kernel.org, robh+dt@kernel.org,
        thara.gopinath@gmail.com, devicetree@vger.kernel.org,
        robh@kernel.org, andersson@kernel.org, bhupesh.linux@gmail.com,
        catalin.marinas@arm.com, will@kernel.org, arnd@arndb.de,
        Jordan Crouse <jorcrous@amazon.com>
References: <20220919221509.1057574-1-bhupesh.sharma@linaro.org>
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From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <CAH=2Ntys+JSurmZn5qN2Kuphi_5q6Ge7cZgd9KMTvAyLnd6JSA@mail.gmail.com>
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On 20/09/2022 12:48, Bhupesh Sharma wrote:
> On Tue, 20 Sept 2022 at 15:09, Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>>
>> On 20/09/2022 10:57, Bhupesh Sharma wrote:
>>>>>             crypto: crypto@8e3a000 {
>>>>> -                   compatible = "qcom,crypto-v5.1";
>>>>> +                   compatible = "qcom,ipq4019-qce";
>>>>
>>>> There are few issues here:
>>>> 1. Compatible is not documented.
>>>
>>> Its documented here:
>>> https://lore.kernel.org/linux-arm-msm/30756e6f-952f-ccf2-b493-e515ba4f0a64@linaro.org/
>>>
>>> [as mentioned in the dependency section in the cover letter :)]
>>>
>>>> 2. Compatible is not supported by old kernel - ABI break.
>>
>> You cannot fix this with dependencies/ordering.
>>
>>>> 3. Everything won't be bisectable...
>>>
>>> I think its a question of dependencies b/w the patchsets intended for
>>> separate areas. Let me think more on how, I can resolve it in newer
>>> versions.
>>
>> DTS always goes separately so this also cannot be fixed with ordering or
>> dependencies. However if Bjorn is fine with it, it's good.
> 
> Sure, I get your point. SInce I haven't sent out the crypto driver and
> DMA driver subsets yet, let me stop and respin the series with the
> dt-bindings changes clubbed with the crypto driver patches in a single
> patchset. I can keep the DMA and dts patchsets separate and send them
> out separately.
> 
> I think that should help maintain the ABI and backward compatibility.
> Please let me know if you think otherwise.

I actually don't know what's in the drivers, so maybe there is no ABI
break by kernel... but you are changing the compatibles in DTS thus any
other project using them will be still broken.

Best regards,
Krzysztof