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Message-ID: <ebcfa5b0-a416-64c0-3aa4-3ae9487c61ab@somainline.org>
Date:   Wed, 6 Jul 2022 14:35:55 +0200
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Subject: Re: [PATCH v3] dt-bindings: qcom: document preferred compatible
 naming
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Vinod Koul <vkoul@kernel.org>, Alex Elder <elder@linaro.org>,
        Robert Foss <robert.foss@linaro.org>,
        Bhupesh Sharma <bhupesh.sharma@linaro.org>
References: <20220705092846.66731-1-krzysztof.kozlowski@linaro.org>
From:   Konrad Dybcio <konrad.dybcio@somainline.org>
In-Reply-To: <20220705092846.66731-1-krzysztof.kozlowski@linaro.org>
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Precedence: bulk


On 5.07.2022 11:28, Krzysztof Kozlowski wrote:
> Compatibles can come in two formats.  Either "vendor,ip-soc" or
> "vendor,soc-ip".  Qualcomm bindings were mixing both of usages, so add a
> DT schema file documenting preferred policy and enforcing it for all new
> compatibles, except few existing patterns.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> ---
> 
> Changes since v2:
> 1. Narrow the expected pattern to be followed by dash '-' after model
>    number (msm8996-) or by two letters and a dash (sc8280xp-).
> 2. Add qcom,apss-wdt-xxx to list of exceptions.
> 3. Use comment instead of description in the oneOf list.
> 
> Changes since v1:
> 1. Add schema instead of readme (Rob).
> 
> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Cc: Vinod Koul <vkoul@kernel.org>
> Cc: Alex Elder <elder@linaro.org>
> Cc: Robert Foss <robert.foss@linaro.org>
> Cc: Bhupesh Sharma <bhupesh.sharma@linaro.org>
> ---
>  .../devicetree/bindings/arm/qcom-soc.yaml     | 57 +++++++++++++++++++
>  1 file changed, 57 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/qcom-soc.yaml
> 
> diff --git a/Documentation/devicetree/bindings/arm/qcom-soc.yaml b/Documentation/devicetree/bindings/arm/qcom-soc.yaml
> new file mode 100644
> index 000000000000..6307c925335d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/qcom-soc.yaml
> @@ -0,0 +1,57 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/arm/qcom-soc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm SoC compatibles naming convention
> +
> +maintainers:
> +  - Bjorn Andersson <bjorn.andersson@linaro.org>
> +
> +description: |
> +  Guidelines for new compatibles for SoC blocks/components.
> +  When adding new compatibles in new bindings, use the format::
> +    qcom,SoC-IP
> +
> +  For example::
> +   qcom,sdm845-llcc-bwmon
> +
> +  When adding new compatibles to existing bindings, use the format in the
> +  existing binding, even if it contradicts the above.
> +
> +select:
> +  properties:
> +    compatible:
> +      pattern: "^qcom,.*(apq|ipq|mdm|msm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
> +  required:
> +    - compatible
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      # Preferred naming style for compatibles of SoC components:
> +      - pattern: "^qcom,(apq|ipq|mdm|msm|qcs|sa|sc|sdm|sdx|sm)[0-9]+-.*$"
> +      - pattern: "^qcom,(sa|sc)8[0-9]+[a-z][a-z]?-.*$"
> +
> +      # Legacy namings - variations of existing patterns/compatibles are OK,
> +      # but do not add completely new entries to these:
> +      - pattern: "^qcom,apss-wdt-(apq|ipq|mdm|msm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
> +      - pattern: "^qcom,gcc-(apq|ipq|mdm|msm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
> +      - pattern: "^qcom,mmcc-(apq|ipq|mdm|msm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
> +      - pattern: "^qcom,pcie-(apq|ipq|mdm|msm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
> +      - pattern: "^qcom,rpm-(apq|ipq|mdm|msm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
> +      - pattern: "^qcom,scm-(apq|ipq|mdm|msm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
> +      - enum:
> +          - qcom,gpucc-sdm630
> +          - qcom,gpucc-sdm660
> +          - qcom,lcc-apq8064
> +          - qcom,lcc-ipq8064
> +          - qcom,lcc-mdm9615
> +          - qcom,lcc-msm8960
> +          - qcom,lpass-cpu-apq8016
> +          - qcom,usb-ss-ipq4019-phy
> +          - qcom,usb-hs-ipq4019-phy
> +          - qcom,vqmmc-ipq4019-regulator
Maybe we could add new compatibles for these drivers and replace them
in upstream DTs, but keep the old ones in the drivers with a clear
indication that they are there only for legacy reasons?

In the specific case of gpucc-sdm630/660 I think we could even "break" backwards
compatibility, as the only users of that driver (Adreno GPU & its SMMU) depend
on an iommu series to function properly, which has been stuck in the freezer..

Konrad
> +
> +additionalProperties: true