linux-kernel - Re: [PATCH v2 1/4] dt-bindings: media: venus: Add an optional power domain for perf voting

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Message-ID: <cd368ea7-6ddc-004c-164d-dbbad8516853@codeaurora.org>
Date:   Fri, 17 Jul 2020 11:22:24 +0530
From:   Rajendra Nayak <rnayak@...eaurora.org>
To:     Rob Herring <robh@...nel.org>
Cc:     stanimir.varbanov@...aro.org, agross@...nel.org,
        bjorn.andersson@...aro.org, linux-arm-msm@...r.kernel.org,
        linux-media@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, mka@...omium.org
Subject: Re: [PATCH v2 1/4] dt-bindings: media: venus: Add an optional power
 domain for perf voting


On 7/17/2020 1:29 AM, Rob Herring wrote:
> On Thu, Jul 16, 2020 at 11:12:16AM +0530, Rajendra Nayak wrote:
>> Add an optional power domain which when specified can be used for
>> setting the performance state of Venus.
> 
> The h/w suddenly grew a new power island/domain? Seems like an abuse of
> power-domains...

The power-domain always existed, we have just managed to survive without
having venus support DVFS and have the domain always be at a high performance
level (set statically by boot code)
Now, if we care to do DVFS and support better PM on the SoC, its important
for the devices to manage this additional power domain (and dynamically
scale it)

That said, if the name 'opp-pd' makes it look like a software construct,
like Bjorn mentioned, I am fine to give it a real name like 'cx-pd'
Does that sound good?

PS: Like I mentioned earlier [1], cx is a shared power island,
not a power island specific to this block, and definitely not a software
pm-domain construct.

[1] https://lore.kernel.org/patchwork/patch/1241077/

> 
>>
>> Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
>> ---
>> This is a resend of https://lore.kernel.org/patchwork/patch/1241077/
>>
>>   Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml    | 6 +++++-
>>   Documentation/devicetree/bindings/media/qcom,sdm845-venus-v2.yaml | 6 +++++-
>>   2 files changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml b/Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml
>> index 55f2d67..1e8675b 100644
>> --- a/Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml
>> +++ b/Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml
>> @@ -25,12 +25,16 @@ properties:
>>       maxItems: 1
>>   
>>     power-domains:
>> -    maxItems: 2
>> +    minItems: 2
>> +    maxItems: 3
>>   
>>     power-domain-names:
>> +    minItems: 2
>> +    maxItems: 3
>>       items:
>>         - const: venus
>>         - const: vcodec0
>> +      - const: opp-pd
>>   
>>     clocks:
>>       maxItems: 5
>> diff --git a/Documentation/devicetree/bindings/media/qcom,sdm845-venus-v2.yaml b/Documentation/devicetree/bindings/media/qcom,sdm845-venus-v2.yaml
>> index 157dff8..437286d 100644
>> --- a/Documentation/devicetree/bindings/media/qcom,sdm845-venus-v2.yaml
>> +++ b/Documentation/devicetree/bindings/media/qcom,sdm845-venus-v2.yaml
>> @@ -25,13 +25,17 @@ properties:
>>       maxItems: 1
>>   
>>     power-domains:
>> -    maxItems: 3
>> +    minItems: 3
>> +    maxItems: 4
>>   
>>     power-domain-names:
>> +    minItems: 3
>> +    maxItems: 4
>>       items:
>>         - const: venus
>>         - const: vcodec0
>>         - const: vcodec1
>> +      - const: opp-pd
>>   
>>     clocks:
>>       maxItems: 7
>> -- 
>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
>> of Code Aurora Forum, hosted by The Linux Foundation
>>

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation