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Date:   Wed, 29 Mar 2023 11:41:41 +0800
From:   Shawn Guo <shawn.guo@linaro.org>
To:     Konrad Dybcio <konrad.dybcio@linaro.org>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
Subject: Re: [PATCH 1/2] dt-bindings: interrupt-controller: mpm: Allow
 passing reg through phandle
Message-ID: <20230329034141.GB3554086@dragon>
References: <20230328-topic-msgram_mpm-v1-0-1b788a5f5a33@linaro.org>
 <20230328-topic-msgram_mpm-v1-1-1b788a5f5a33@linaro.org>
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On Tue, Mar 28, 2023 at 12:02:52PM +0200, Konrad Dybcio wrote:
> Due to the wild nature of the Qualcomm RPM Message RAM, we can't really
> use 'reg' to point to the MPM's slice of Message RAM without cutting into
> an already-defined RPM MSG RAM node used for GLINK and SMEM.
> 
> Document passing the register space as a slice of SRAM through the
> qcom,rpm-msg-ram property. This also makes 'reg' no longer required.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> ---
>  .../devicetree/bindings/interrupt-controller/qcom,mpm.yaml          | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/qcom,mpm.yaml b/Documentation/devicetree/bindings/interrupt-controller/qcom,mpm.yaml
> index 509d20c091af..77fe5e0b378f 100644
> --- a/Documentation/devicetree/bindings/interrupt-controller/qcom,mpm.yaml
> +++ b/Documentation/devicetree/bindings/interrupt-controller/qcom,mpm.yaml
> @@ -30,6 +30,11 @@ properties:
>      description:
>        Specifies the base address and size of vMPM registers in RPM MSG RAM.
>  
> +  qcom,rpm-msg-ram:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      Phandle to the APSS MPM slice of the RPM Message RAM
> +
>    interrupts:
>      maxItems: 1
>      description:
> @@ -64,7 +69,6 @@ properties:
>  
>  required:
>    - compatible
> -  - reg

It's not my call, but I wonder if we need to maintain the 'reg' ABI
at all, as there is no DTS landed so far.  In either case, I suggest
we update the example to adopt the new way.

Shawn

>    - interrupts
>    - mboxes
>    - interrupt-controller
> 
> -- 
> 2.40.0
>