linux-kernel - Re: [PATCH v2 1/8] dt-bindings: clock: qcom: Allow VDD

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Message-ID: <4e56729e-0549-4075-8f6c-a43c84ae9b9a@linaro.org>
Date: Sat, 30 Dec 2023 00:51:50 +0100
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Bjorn Andersson <quic_bjorande@...cinc.com>,
 Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: Bjorn Andersson <andersson@...nel.org>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, Rob Herring <robh+dt@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 Conor Dooley <conor+dt@...nel.org>, Taniya Das <quic_tdas@...cinc.com>,
 Ulf Hansson <ulf.hansson@...aro.org>, Johan Hovold
 <johan+linaro@...nel.org>, Catalin Marinas <catalin.marinas@....com>,
 Will Deacon <will@...nel.org>, linux-arm-msm@...r.kernel.org,
 linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 1/8] dt-bindings: clock: qcom: Allow VDD_GFX supply to
 GX

On 27.12.2023 21:30, Bjorn Andersson wrote:
> On Fri, Dec 22, 2023 at 09:12:04AM +0100, Krzysztof Kozlowski wrote:
>> On 22/12/2023 05:39, Bjorn Andersson wrote:
>>> In some designs the SoC's VDD_GFX pads are supplied by an external
>>> regulator, rather than a power-domain. Allow this to be described in the
>>> GPU clock controller binding.
>>>
>>> Signed-off-by: Bjorn Andersson <quic_bjorande@...cinc.com>
>>> ---
>>>  Documentation/devicetree/bindings/clock/qcom,gpucc.yaml | 16 ++++++++++++++++
>>>  1 file changed, 16 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/clock/qcom,gpucc.yaml b/Documentation/devicetree/bindings/clock/qcom,gpucc.yaml
>>> index f369fa34e00c..c0dd24c9dcb3 100644
>>> --- a/Documentation/devicetree/bindings/clock/qcom,gpucc.yaml
>>> +++ b/Documentation/devicetree/bindings/clock/qcom,gpucc.yaml
>>> @@ -53,6 +53,9 @@ properties:
>>>    power-domains:
>>>      maxItems: 1
>>>  
>>> +  vdd-gfx-supply:
>>> +    description: Regulator supply for the VDD_GFX pads
>>> +
>>>    '#clock-cells':
>>>      const: 1
>>>  
>>> @@ -74,6 +77,19 @@ required:
>>>    - '#reset-cells'
>>>    - '#power-domain-cells'
>>>  
>>> +# Allow either power-domains or vdd-gfx-supply, not both
>>> +oneOf:
>>> +  - required:
>>> +      - power-domains
>>> +  - required:
>>> +      - vdd-gfx-supply
>>
>> This should be enough, assuming one of them is actually required. The
>> code. See also:
>> https://elixir.bootlin.com/linux/v5.17-rc2/source/Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml#L91
>>
> 
> Yes, that would be the correct binding. But the majority of our
> DeviceTree source does not specify a power-domain for their gpucc.
> 
> While this should be corrected, it seem reasonable to leave this
> optional for now.
Moreover, I think it would be reasonable to add power-domains as
required in qcom,gcc.yaml. IIRC all "normal" (not q6) clock controllers
use at least CX+MX, with perhaps more hw-specific domains for some clocks
or GDSCs.

Konrad