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Message-ID: <c892f773-7716-4736-3499-5c8254e3618e@quicinc.com>
Date: Fri, 8 Mar 2024 18:10:13 +0530
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Subject: Re: [PATCH 4/5] clk: qcom: Add camera clock controller driver for
 SM8150
Content-Language: en-US
To: Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
        Bjorn Andersson
	<andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        "Michael
 Turquette" <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, Abhishek Sahu <absahu@codeaurora.org>,
        Rob Herring <robh@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley
	<conor+dt@kernel.org>
CC: Stephen Boyd <sboyd@codeaurora.org>, <linux-arm-msm@vger.kernel.org>,
        <linux-clk@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <devicetree@vger.kernel.org>, Ajit Pandey <quic_ajipan@quicinc.com>,
        "Imran
 Shaik" <quic_imrashai@quicinc.com>,
        Taniya Das <quic_tdas@quicinc.com>,
        Jagadeesh Kona <quic_jkona@quicinc.com>
References: <20240229-camcc-support-sm8150-v1-0-8c28c6c87990@quicinc.com>
 <20240229-camcc-support-sm8150-v1-4-8c28c6c87990@quicinc.com>
 <18567989-fb60-49ae-92e6-94e1bc2fa1c7@linaro.org>
 <83fd1995-a06e-b76a-d91b-de1c1a6ab0ea@quicinc.com>
 <4817a5b0-5407-4437-b94a-fc8a1bfcd25d@linaro.org>
 <e2627a99-307f-1e10-abfd-ce688cc2ec03@quicinc.com>
 <d893e8f8-66a7-4460-9468-0f3a359cece7@linaro.org>
 <35a7ad40-aaf4-476e-8582-b83bac284881@linaro.org>
From: "Satya Priya Kakitapalli (Temp)" <quic_skakitap@quicinc.com>
In-Reply-To: <35a7ad40-aaf4-476e-8582-b83bac284881@linaro.org>
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On 3/8/2024 4:29 PM, Bryan O'Donoghue wrote:
> On 08/03/2024 10:58, Bryan O'Donoghue wrote:
>> On 08/03/2024 10:46, Satya Priya Kakitapalli (Temp) wrote:
>>>>
>>>> Not if you mark it critical
>>>>
>>>
>>> Marking the clock as critical keeps the associated power domain 
>>> always-on which impacts power. For this reason we are not using 
>>> CLK_IS_CRITICAL and instead making them always on from probe.
>>
>> How does the clock do anything _useful_ if the power-domain gets 
>> switched off ?
>>
>> ---
>> bod
>
> i.e. the clock can't be running "always-on" if it has no power..
>

If BIT(0) is set from probe, during any active usecase, the clock gets 
turned ON automatically when the power domain is turned ON.

But when we use CLK_IS_CRITICAL flag, the framework keeps the power 
domain ON and doesn't let the power domain to turn off even when there 
is no active usecase.