linux-kernel - Re: [PATCH v3 2/5] dt-bindings: cpufreq: apple,soc-cpufreq: Add binding for Apple SoC cpufreq

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Message-ID: <97d3d6d4-b19c-a194-de41-f17e65bf3eb6@marcan.st>
Date:   Wed, 26 Oct 2022 02:22:40 +0900
From:   Hector Martin <marcan@...can.st>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>
Cc:     Sven Peter <sven@...npeter.dev>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Marc Zyngier <maz@...nel.org>,
        Mark Kettenis <mark.kettenis@...all.nl>, asahi@...ts.linux.dev,
        linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/5] dt-bindings: cpufreq: apple,soc-cpufreq: Add
 binding for Apple SoC cpufreq

On 26/10/2022 01.01, Krzysztof Kozlowski wrote:
> On 24/10/2022 00:39, Hector Martin wrote:
>> This binding represents the cpufreq/DVFS hardware present in Apple SoCs.
>> The hardware has an independent controller per CPU cluster, and we
>> represent them as unique nodes in order to accurately describe the
>> hardware. The driver is responsible for binding them as a single cpufreq
>> device (in the Linux cpufreq model).
>>
>> Signed-off-by: Hector Martin <marcan@...can.st>
>> ---
>>  .../cpufreq/apple,cluster-cpufreq.yaml        | 119 ++++++++++++++++++
>>  1 file changed, 119 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/cpufreq/apple,cluster-cpufreq.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/cpufreq/apple,cluster-cpufreq.yaml b/Documentation/devicetree/bindings/cpufreq/apple,cluster-cpufreq.yaml
>> new file mode 100644
>> index 000000000000..b11452f91468
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/cpufreq/apple,cluster-cpufreq.yaml
>> @@ -0,0 +1,119 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/cpufreq/apple,cluster-cpufreq.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Apple SoC cluster cpufreq device
> 
> Few nits, in general looks fine to me.
> 
>> +
>> +maintainers:
>> +  - Hector Martin <marcan@...can.st>
>> +
>> +description: |
>> +  Apple SoCs (e.g. M1) have a per-cpu-cluster DVFS controller that is part of
>> +  the cluster management register block. This binding uses the standard
>> +  operating-points-v2 table to define the CPU performance states, with the
>> +  opp-level property specifying the hardware p-state index for that level.
>> +
>> +properties:
>> +  compatible:
>> +    oneOf:
>> +      - items:
>> +          - const: apple,t8103-cluster-cpufreq
>> +          - const: apple,cluster-cpufreq
>> +      - items:
>> +          - const: apple,t6000-cluster-cpufreq
>> +          - const: apple,t8103-cluster-cpufreq
>> +          - const: apple,cluster-cpufreq
>> +      - items:
>> +          - const: apple,t8112-cluster-cpufreq
> 
> With the first one (t8103) - it's an enum.

This is deliberate. t6000 is compatible with t8103, but t8112 is not
(though all are compatible with what the generic apple,cluster-cpufreq
compatible implies).

Ack on the rest, I'll spin a v4 in a few days if there are no other
comments. Thanks!

- Hector