From: Rob Herring <robh@kernel.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>,
Manivannan Sadhasivam <mani@kernel.org>,
Andy Gross <agross@kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Johan Hovold <johan@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 1/4] dt-bindings: cpufreq-qcom-hw: Move clocks to CPU nodes
Date: Mon, 18 Jul 2022 14:46:51 -0600 [thread overview]
Message-ID: <20220718204651.GA3505083-robh@kernel.org> (raw)
In-Reply-To: <035fe13689dad6d3867a1d33f7d5e91d4637d14a.1657695140.git.viresh.kumar@linaro.org>
On Wed, Jul 13, 2022 at 12:22:56PM +0530, Viresh Kumar wrote:
> cpufreq-hw is a hardware engine, which takes care of frequency
> management for CPUs. The engine manages the clocks for CPU devices, but
> it isn't the end consumer of the clocks, which are the CPUs in this
> case.
The question is really where does the clock mux live?
> For this reason, it looks incorrect to keep the clock related properties
> in the cpufreq-hw node. They should really be present at the end user,
> i.e. the CPUs.
The issue is that the CPU itself probably only has 1 clock input (at
least for its core frequency). Listing out all possible clock sources in
CPU node 'clocks' is wrong too.
> The case was simple currently as all the devices, i.e. the CPUs, that
> the engine manages share the same clock names. What if the clock names
> are different for different CPUs or clusters ? How will keeping the
> clock properties in the cpufreq-hw node work in that case ?
>
> This design creates further problems for frameworks like OPP, which
> expects all such details (clocks) to be present in the end device node
> itself, instead of another related node.
>
> Move the clocks properties to the node that uses them instead.
What's the purpose of freq-domain binding now? I thought the idea was to
use that instead of clocks directly.
Rob
next prev parent reply other threads:[~2022-07-18 20:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-13 6:52 [RFC PATCH 0/4] cpufreq: qcom-hw: Move clocks to CPU node Viresh Kumar
2022-07-13 6:52 ` [RFC PATCH 1/4] dt-bindings: cpufreq-qcom-hw: Move clocks to CPU nodes Viresh Kumar
2022-07-18 20:46 ` Rob Herring [this message]
2022-07-19 4:19 ` Viresh Kumar
2022-07-13 6:52 ` [RFC PATCH 2/4] arm64: dts: qcom: " Viresh Kumar
2022-07-13 6:52 ` [RFC PATCH 3/4] cpufreq: qcom-cpufreq-hw: Clocks are moved " Viresh Kumar
2022-07-13 6:52 ` [RFC PATCH 4/4] cpufreq: qcom-cpufreq-hw: Register config_clks helper Viresh Kumar
2022-07-15 16:09 ` [RFC PATCH 0/4] cpufreq: qcom-hw: Move clocks to CPU node Manivannan Sadhasivam
2022-07-18 1:57 ` Viresh Kumar
2022-08-01 2:37 ` Viresh Kumar
2022-08-01 5:42 ` Manivannan Sadhasivam
2022-08-30 3:24 ` Bjorn Andersson
2022-08-30 5:40 ` Viresh Kumar
2022-08-30 6:20 ` Manivannan Sadhasivam
2022-09-20 10:28 ` Viresh Kumar
2022-09-26 11:34 ` Manivannan Sadhasivam
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