Message-ID: <2b3e39b9-ea70-db9b-89f7-09054df363c3@linaro.org>
Date:   Wed, 15 Mar 2023 08:41:21 +0100
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Subject: Re: [PATCH v2 2/5] dt-bindings: arm: msm: Add bindings for multi
 channel DDR in LLCC
Content-Language: en-US
To:     Komal Bajaj <quic_kbajaj@quicinc.com>,
        Rob Herring <robh+dt@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Abel Vesa <abel.vesa@linaro.org>,
        Rishabh Bhatnagar <rishabhb@codeaurora.org>,
        Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-msm@vger.kernel.org
References: <20230313124040.9463-1-quic_kbajaj@quicinc.com>
 <20230313124040.9463-3-quic_kbajaj@quicinc.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20230313124040.9463-3-quic_kbajaj@quicinc.com>
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Precedence: bulk

On 13/03/2023 13:40, Komal Bajaj wrote:
> Add description for additional nodes needed to support
> mulitple channel DDR configurations in LLCC.
> 
> Signed-off-by: Komal Bajaj <quic_kbajaj@quicinc.com>

+Cc Mani,

This will conflict with:
https://lore.kernel.org/all/20230314080443.64635-3-manivannan.sadhasivam@linaro.org/

Please rebase on top of Mani's patches (assuming they are not
conflicting in principle)

> ---
>  Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml b/Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml
> index 38efcad56dbd..9a4a76caf490 100644
> --- a/Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml
> +++ b/Documentation/devicetree/bindings/arm/msm/qcom,llcc.yaml
> @@ -37,15 +37,24 @@ properties:
>      items:

minItems: 2

>        - description: LLCC base register region
>        - description: LLCC broadcast base register region
> +      - description: Feature register to decide which LLCC configuration
> +                     to use, this is optional
>  
>    reg-names:

minItems: 2

>      items:
>        - const: llcc_base
>        - const: llcc_broadcast_base
> +      - const: multi_channel_register
>  
>    interrupts:
>      maxItems: 1
>  
> +  multi-ch-bit-off:
> +    items:
> +      - description: Specifies the offset in bits into the multi_channel_register
> +                     and the number of bits used to decide which LLCC configuration
> +                     to use

There are here few issues.
First, I don't fully understand the property. What is an LLCC
configuration? Like some fused values?

Second, don't make it a register specific, it will not scale easily to
any new version of this interface. Although how this should look like
depends on what is it.

Third, you need vendor prefix and type (unless this is a generic
property, but does not look like). Then "items" is probably wrong. Line
break after "description: "

Best regards,
Krzysztof