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From: Taniya Das <taniya.das@oss.qualcomm.com>
To: Bjorn Andersson <andersson@kernel.org>
Cc: Abel Vesa <abel.vesa@oss.qualcomm.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Konrad Dybcio <konradybcio@kernel.org>,
	Maulik Shah <maulik.shah@oss.qualcomm.com>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
	Jyothi Kumar Seerapu <jyothi.seerapu@oss.qualcomm.com>,
	Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>,
	Brian Masney <bmasney@redhat.com>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Sibi Sankar <sibi.sankar@oss.qualcomm.com>,
	Pankaj Patil <pankaj.patil@oss.qualcomm.com>,
	Akhil P Oommen <akhilpo@oss.qualcomm.com>,
	linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jishnu Prakash <jishnu.prakash@oss.qualcomm.com>,
	Raviteja Laggyshetty <raviteja.laggyshetty@oss.qualcomm.com>,
	Kamal Wadhwa <kamal.wadhwa@oss.qualcomm.com>,
	Qiang Yu <qiang.yu@oss.qualcomm.com>,
	Manaf Meethalavalappu Pallikunhi
	<manaf.pallikunhi@oss.qualcomm.com>,
	Abel Vesa <abelvesa@kernel.org>
Subject: Re: [PATCH v3 1/3] dt-bindings: clock: qcom: glymur-gcc: Add missing CX power domain
Date: Fri, 17 Jul 2026 15:00:11 +0530	[thread overview]
Message-ID: <2e9a211d-a877-419a-ba8d-40bfc42e65ef@oss.qualcomm.com> (raw)
In-Reply-To: <almBxBhYxTR9n5FZ@baldur>



On 7/17/2026 6:45 AM, Bjorn Andersson wrote:
> On Thu, Jul 16, 2026 at 04:42:11PM +0530, Taniya Das wrote:
>>
>>
>> On 7/16/2026 12:52 PM, Abel Vesa wrote:
>>> On 26-07-16 10:13:48, Taniya Das wrote:
>>>>
>>>>
>>>> On 7/15/2026 6:59 PM, Abel Vesa wrote:
>>>>> The GDSCs provided by the Glymur GCC are supplied by the RPMh CX power
>>>>> domain. Model that parent domain in the GCC binding so the provider can
>>>>> describe the dependency in devicetree.
>>>>>
>>>>> Add a single CX power-domain entry to the binding and make it required,
>>>>> matching the hardware description needed by the GCC node.
>>>>>
>>>>> Fixes: ee2d967030fe ("dt-bindings: clock: qcom: document the Glymur Global Clock Controller")
>>>>> Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
>>>>> ---
>>>>>  Documentation/devicetree/bindings/clock/qcom,glymur-gcc.yaml | 8 ++++++++
>>>>>  1 file changed, 8 insertions(+)
>>>>
>>>>
>>>> Abel, I feel we should add the 'required-opps' as well which will ensure
>>>> the clock controllers minimum voltage requirement.
>>>
>>> But it was agreed in v1 that we should not add the required-opps. So we
>>> dropped it in v2.
>>>
>>
>> Okay, sorry, may be I missed that comment.
>>
>>
>>> Can you give more details to why you think it is needed ?
>>
>> My reasoning is that if a clock controller requires a rail, it is
>> preferable to explicitly specify the required operating level rather
>> than rely on system/client vote. This makes the dependency
>> self-contained and easier to reason about. Clients that require a higher
>> operating level than the clock controller's minimum requirement remain
>> free to vote for a higher level as needed.
>>
> 
> You're expressing this in generic terms, can you please provide the
> concrete example of what this would look for in the Glymur GCC case? 
> 

Yes, Bjorn, this is indeed a general requirement for a clock controller.

In Glymur I do see that CX could drop to retention corner in case there
is no vote from any subsystem and so it is better to vote from clock
controller a level above retention using the required-opps.

> What is the required-opps for the Glymur GCC?

LOW_SVS(rpmhpd_opp_low_svs) corner should be good for GCC controller.

-- 
Thanks,
Taniya Das


  reply	other threads:[~2026-07-17  9:30 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-15 13:29 [PATCH v3 0/3] clk: qcom: gcc-glymur: Tie the CX power domain to controller Abel Vesa
2026-07-15 13:29 ` [PATCH v3 1/3] dt-bindings: clock: qcom: glymur-gcc: Add missing CX power domain Abel Vesa
2026-07-16  4:43   ` Taniya Das
2026-07-16  7:22     ` Abel Vesa
2026-07-16 11:12       ` Taniya Das
2026-07-17  1:15         ` Bjorn Andersson
2026-07-17  9:30           ` Taniya Das [this message]
2026-07-17  9:34             ` Konrad Dybcio
2026-07-15 13:29 ` [PATCH v3 2/3] clk: qcom: gcc-glymur: Enable runtime PM Abel Vesa
2026-07-15 13:46   ` sashiko-bot
2026-07-15 13:29 ` [PATCH v3 3/3] arm64: dts: qcom: glymur: Add CX power domain to GCC Abel Vesa
2026-07-15 13:32   ` Konrad Dybcio
2026-07-17  3:23 ` (subset) [PATCH v3 0/3] clk: qcom: gcc-glymur: Tie the CX power domain to controller Bjorn Andersson

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