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Message-ID: <f3882934-9f95-39f1-83e4-6ce9efeb089c@linaro.org>
Date:   Thu, 3 Nov 2022 08:25:17 -0400
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Subject: Re: [PATCH 05/10] dt-bindings: interconnect: Add sm8350, sc8280xp and
 generic OSM L3 compatibles
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To:     Bjorn Andersson <quic_bjorande@quicinc.com>
Cc:     Georgi Djakov <djakov@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Sibi Sankar <quic_sibis@quicinc.com>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@somainline.org>,
        Mike Tipton <quic_mdtipton@quicinc.com>,
        Johan Hovold <johan+linaro@kernel.org>,
        linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20221028034155.5580-1-quic_bjorande@quicinc.com>
 <20221028034155.5580-6-quic_bjorande@quicinc.com>
 <a364b343-fa19-348c-bc38-e8b44061890b@linaro.org>
 <20221103034410.GB5525@core-thresher1.qualcomm.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20221103034410.GB5525@core-thresher1.qualcomm.com>
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Precedence: bulk

On 02/11/2022 23:44, Bjorn Andersson wrote:
> On Fri, Oct 28, 2022 at 06:12:29PM -0400, Krzysztof Kozlowski wrote:
>> On 27/10/2022 23:41, Bjorn Andersson wrote:
>>> Add EPSS L3 compatibles for sm8350 and sc8280xp, but while at it also
>>> introduce generic compatible for both qcom,osm-l3 and qcom,epss-l3.
>>>
>>> Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
>>> ---
>>>  .../bindings/interconnect/qcom,osm-l3.yaml    | 22 +++++++++++++------
>>>  1 file changed, 15 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/interconnect/qcom,osm-l3.yaml b/Documentation/devicetree/bindings/interconnect/qcom,osm-l3.yaml
>>> index bf538c0c5a81..ae0995341a78 100644
>>> --- a/Documentation/devicetree/bindings/interconnect/qcom,osm-l3.yaml
>>> +++ b/Documentation/devicetree/bindings/interconnect/qcom,osm-l3.yaml
>>> @@ -16,13 +16,21 @@ description:
>>>  
>>>  properties:
>>>    compatible:
>>> -    enum:
>>> -      - qcom,sc7180-osm-l3
>>> -      - qcom,sc7280-epss-l3
>>> -      - qcom,sc8180x-osm-l3
>>> -      - qcom,sdm845-osm-l3
>>> -      - qcom,sm8150-osm-l3
>>> -      - qcom,sm8250-epss-l3
>>> +    oneOf:
>>> +      items:
>>
>> oneOf expects a list, so this should be "    - items"
>>
> 
> Ahh, thanks. Must have missed running the dt_binding_check on this one.
> 
>>> +        - enum:
>>> +            - qcom,sc7180-osm-l3
>>> +            - qcom,sc8180x-osm-l3
>>> +            - qcom,sdm845-osm-l3
>>> +            - qcom,sm8150-osm-l3
>>> +        - const: qcom,osm-l3
>>
>> The concept is good, but are you sure all SoCs will be compatible with
>> generic osm-l3?
> 
> Per the current implementation yes, worst case if one or more of them isn't the
> more specific compatible can be used to alter the behavior of that platform.
> 
>> Why not using dedicated compatible of one soc, e.g. the
>> oldest here? We already did like that for BWMON, DMA and few others.
>>
> 
> Because if we say compatible = "qcom,sc8180x-osm-l3", "qcom,sdm845-osm-l3" and
> there is a quirk needed for "qcom,sdm845-osm-l3" we're forced to add a "special
> case" every other *-osm-l3 in the driver.
> 
> This way we can have a generic implementation for the qcom,osm-l3 and if we
> realize that we need to quirk something for the oldest platform, we can do so
> without affecting the others.

True. This also means we do not really know which one is the generic
implementation :)


Best regards,
Krzysztof