linux-kernel - Re: [PATCH 09/19] arm: dts: qcom: sdx55/sdx65: Fix CPU power-domain-names

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Message-ID: <898bebc3-e2b1-4819-9869-05b783509146@oss.qualcomm.com>
Date: Thu, 10 Apr 2025 18:25:11 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Stephan Gerhold <stephan.gerhold@...aro.org>,
        Konrad Dybcio <konrad.dybcio@....qualcomm.com>
Cc: Ulf Hansson <ulf.hansson@...aro.org>,
        "Rob Herring (Arm)"
 <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Samuel Holland <samuel@...lland.org>,
        "Rafael J. Wysocki"
 <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Liviu Dudau <liviu.dudau@....com>, Sudeep Holla <sudeep.holla@....com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>, zhouyanjie@...yeetech.com,
        Conor Dooley <conor@...nel.org>,
        Nicolas Ferre
 <nicolas.ferre@...rochip.com>,
        Claudiu Beznea <claudiu.beznea@...on.dev>,
        Steen Hegelund <Steen.Hegelund@...rochip.com>,
        Daniel Machon <daniel.machon@...rochip.com>,
        UNGLinuxDriver@...rochip.com, Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>, Heiko Stuebner <heiko@...ech.de>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
        linux-mips@...r.kernel.org, imx@...ts.linux.dev,
        linux-rockchip@...ts.infradead.org, linux-amlogic@...ts.infradead.org,
        linux-renesas-soc@...r.kernel.org,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Subject: Re: [PATCH 09/19] arm: dts: qcom: sdx55/sdx65: Fix CPU
 power-domain-names

On 4/10/25 9:10 AM, Stephan Gerhold wrote:
> On Wed, Apr 09, 2025 at 08:35:29PM +0200, Konrad Dybcio wrote:
>> On 4/7/25 6:27 PM, Ulf Hansson wrote:
>>> On Fri, 4 Apr 2025 at 22:41, Konrad Dybcio
>>> <konrad.dybcio@....qualcomm.com> wrote:
>>>>
>>>> On 4/4/25 4:59 AM, Rob Herring (Arm) wrote:
>>>>> "rpmhpd" is not documented nor used anywhere. As the enable-method is
>>>>> "psci" use "psci" for the power-domain name.
>>>>>
>>>>> Signed-off-by: Rob Herring (Arm) <robh@...nel.org>
>>>>> ---
>>>>
>>>> "psci" is what we want here, but these platforms require some more
>>>> massaging..
>>>
>>> So this isn't for CPU performance scaling?
>>
>> Nope!
>>
> 
> Huh, this is definitely "perf" (= cpufreq) and not "psci" (= cpuidle).
> If you run blame on this line you get to:
> 
> commit 0ec7bde7b590f8efa5823df3b52b32dd373060ff
> Author: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> Date:   Thu Apr 8 22:34:45 2021 +0530
> 
>     ARM: dts: qcom: sdx55: Add CPUFreq support
> 
>     Add CPUFreq support to SDX55 platform using the cpufreq-dt driver.
>     There is no dedicated hardware block available on this platform to
>     carry on the CPUFreq duties. Hence, it is accomplished using the CPU
>     clock and regulators tied together by the operating points table.
> 
> https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0ec7bde7b590f8efa5823df3b52b32dd373060ff
> 
> The OPP table looks like it's supposed to set SDX55_CX performance
> states according to the chosen CPU frequency. MSM8909 has a similar
> setup where the CPU is supplied directly by VDDCX and we describe that
> with "perf" too [1].

Ohh right I was under the impression that qcom,cpufreq-hw is used on
those too, but apparently not..

Konrad