linux-kernel - Re: [PATCH v3 2/2] dt-bindings: arm: Add device-name in the coresight components

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Date: Fri, 2 Feb 2024 13:38:08 -0600
From: Rob Herring <robh@...nel.org>
To: Mao Jinlong <quic_jinlmao@...cinc.com>
Cc: Suzuki K Poulose <suzuki.poulose@....com>,
	Mike Leach <mike.leach@...aro.org>,
	James Clark <james.clark@....com>, Leo Yan <leo.yan@...aro.org>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Alexandre Torgue <alexandre.torgue@...s.st.com>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Mathieu Poirier <mathieu.poirier@...aro.org>,
	coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-msm@...r.kernel.org,
	Tingwei Zhang <quic_tingweiz@...cinc.com>,
	Yuanfang Zhang <quic_yuanfang@...cinc.com>,
	Tao Zhang <quic_taozha@...cinc.com>
Subject: Re: [PATCH v3 2/2] dt-bindings: arm: Add device-name in the
 coresight components

On Wed, Jan 31, 2024 at 12:26:26AM -0800, Mao Jinlong wrote:
> Current name of coresight component's folder consists of prefix of
> the device and the id in the device list. When run 'ls' command,
> we can get the register address of the device. Take CTI for example,
> if we want to set the config for modem CTI, but we can't know which
> CTI is modem CTI from all current information.
> 
> cti_sys0 -> ../../../devices/platform/soc@...38f0000.cti/cti_sys0
> cti_sys1 -> ../../../devices/platform/soc@...3900000.cti/cti_sys1
> 
> Add device-name in device tree which can provide a better description
> of the coresight device. It can provide the info like the system or
> HW it belongs to.
> 
> Signed-off-by: Mao Jinlong <quic_jinlmao@...cinc.com>
> ---
>  .../devicetree/bindings/arm/arm,coresight-catu.yaml         | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-cpu-debug.yaml    | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-cti.yaml          | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-dummy-sink.yaml   | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-dummy-source.yaml | 6 ++++++
>  .../bindings/arm/arm,coresight-dynamic-funnel.yaml          | 6 ++++++
>  .../bindings/arm/arm,coresight-dynamic-replicator.yaml      | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-etb10.yaml        | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-etm.yaml          | 6 ++++++
>  .../bindings/arm/arm,coresight-static-funnel.yaml           | 6 ++++++
>  .../bindings/arm/arm,coresight-static-replicator.yaml       | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-stm.yaml          | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-tmc.yaml          | 6 ++++++
>  .../devicetree/bindings/arm/arm,coresight-tpiu.yaml         | 6 ++++++
>  .../devicetree/bindings/arm/qcom,coresight-tpda.yaml        | 6 ++++++
>  .../devicetree/bindings/arm/qcom,coresight-tpdm.yaml        | 6 ++++++

Why do you need a name on everything? Funnels and replicators, for 
example, aren't a source of data, but just connected to things that are. 
ETM is tightly coupled to a CPU and you have a link to it. You have 
graph links to show connections. Limit this to where you actually need 
it. 

>  16 files changed, 96 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/arm/arm,coresight-catu.yaml b/Documentation/devicetree/bindings/arm/arm,coresight-catu.yaml
> index 2bae06eed693..a4d20aad0c70 100644
> --- a/Documentation/devicetree/bindings/arm/arm,coresight-catu.yaml
> +++ b/Documentation/devicetree/bindings/arm/arm,coresight-catu.yaml
> @@ -44,6 +44,12 @@ properties:
>        - const: arm,coresight-catu
>        - const: arm,primecell
>  
> +  device-name:

This is too generic of a name. Make is something closer to how it is 
used or what it is for. Naming sysfs devices is not how it is used. 
That's just an intermediate step.

> +    $ref: /schemas/types.yaml#/definitions/string
> +    description:
> +      Define the name which can describe what kind of HW or system the
> +      device is for.
> +
>    reg:
>      maxItems: 1
>  
> diff --git a/Documentation/devicetree/bindings/arm/arm,coresight-cpu-debug.yaml b/Documentation/devicetree/bindings/arm/arm,coresight-cpu-debug.yaml
> index 0a6bc03ebe00..6094cc9cb834 100644
> --- a/Documentation/devicetree/bindings/arm/arm,coresight-cpu-debug.yaml
> +++ b/Documentation/devicetree/bindings/arm/arm,coresight-cpu-debug.yaml
> @@ -39,6 +39,12 @@ properties:
>        - const: arm,coresight-cpu-debug
>        - const: arm,primecell
>  
> +  device-name:
> +    $ref: /schemas/types.yaml#/definitions/string

If you are redefining the type multiple times, there's a problem in the 
structure of the schemas. Really, that's true for anything duplicated in 
the kernel.

Rob