linux-kernel - Re: [PATCH 4/9] dt-bindings: arm: qcom,coresight-static-replicator: add optional clocks

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Message-ID: <eeff769a-ff81-4017-9738-98ad130980a9@arm.com>
Date: Tue, 18 Mar 2025 13:37:23 +0000
From: Suzuki K Poulose <suzuki.poulose@....com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
 Mike Leach <mike.leach@...aro.org>
Cc: Bjorn Andersson <andersson@...nel.org>,
 Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Lee Jones <lee@...nel.org>,
 Neil Armstrong <neil.armstrong@...aro.org>, Rob Clark <robdclark@...il.com>,
 Abhinav Kumar <quic_abhinavk@...cinc.com>,
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, Sean Paul <sean@...rly.run>,
 Marijn Suijten <marijn.suijten@...ainline.org>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 Mike Leach <mike.leach@...aro.org>, James Clark <james.clark@...aro.org>,
 Leo Yan <leo.yan@...ux.dev>, Kumar Gala <galak@...eaurora.org>,
 Andy Gross <agross@...eaurora.org>, "Ivan T. Ivanov"
 <ivan.ivanov@...aro.org>, Andy Gross <andy.gross@...aro.org>,
 Georgi Djakov <djakov@...nel.org>, David Heidelberg <david@...t.cz>,
 linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
 freedreno@...ts.freedesktop.org, coresight@...ts.linaro.org,
 linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 4/9] dt-bindings: arm: qcom,coresight-static-replicator:
 add optional clocks

On 18/03/2025 12:19, Dmitry Baryshkov wrote:
> On Tue, Mar 18, 2025 at 10:38:17AM +0000, Suzuki K Poulose wrote:
>> On 17/03/2025 17:44, Dmitry Baryshkov wrote:
>>
>> nit: Subject:
>>
>> s/qcom,coresight-static-replicator/arm,coresight-static-replicator
>>
>>> As most other CoreSight devices the replicator can use either of the
>>> optional clocks (or both). Document those optional clocks in the schema.
>>>
>>> Fixes: 3c15fddf3121 ("dt-bindings: arm: Convert CoreSight bindings to DT schema")
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
>>> ---
>>>    .../bindings/arm/arm,coresight-static-replicator.yaml          | 10 ++++++++++
>>>    1 file changed, 10 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/arm/arm,coresight-static-replicator.yaml b/Documentation/devicetree/bindings/arm/arm,coresight-static-replicator.yaml
>>> index a6f793ea03b6c193fc0ff72a45e0249a63a2ba3c..56e64067ed3d63c5e293a0840858f13428bacb45 100644
>>> --- a/Documentation/devicetree/bindings/arm/arm,coresight-static-replicator.yaml
>>> +++ b/Documentation/devicetree/bindings/arm/arm,coresight-static-replicator.yaml
>>> @@ -30,6 +30,16 @@ properties:
>>>      power-domains:
>>>        maxItems: 1
>>> +  clocks:
>>> +    minItems: 1
>>> +    maxItems: 2
>>> +
>>
>> For the static replicator, you don't have an APB clock, as they can't be
>> programmed. It may have an ATB clock. So minItems 0, maxItems: 1
> 
> It can, see qcom-apq8064.dtsi
> 
> Also minItems:0 doesn't make sense to me. I'd rather keep this as an
> optional property rather than requiring an empty set.

Interesting, that must be atclk in fact. Because a static replicator
only manages ATB transactions. It doesn't have an APB interface.

I am not an expert in DTB schema. But the point is the clocks are optional.

Suzuki

> 
>>
>> Suzuki
>>
>>
>>
>>> +  clock-names:
>>> +    minItems: 1
>>> +    enum:
>>> +      - apb_pclk
>>> +      - atclk
>>> +
>>>      in-ports:
>>>        $ref: /schemas/graph.yaml#/properties/ports
>>>        additionalProperties: false
>>>
>>
>