RFC cpufreq: qcom-hw: Move clocks to CPU node

Hi,

A recent patch series, targeting enhancements in the OPP core, ended up breaking cpufreq on some of the Qualcomm platforms [1]. Necessary adjustments are made in the OPP core, a bit hacky though, to get it working for now but it would be better to solve the problem at hand in a cleaner way. And this patchset is an attempt towards the same.

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.

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 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.

This patchset moves the clock properties to the node that uses them instead, i.e. the CPU nodes and makes necessary adjustments at other places.

After this is applied, I can drop the unnecessary change from the OPP core, but I wanted to discuss if this is a step in the right direction or not first and so the RFC.

--
Viresh

[1] https://lore.kernel.org/lkml/[email protected]/

Viresh Kumar (4):
dt-bindings: cpufreq-qcom-hw: Move clocks to CPU nodes
arm64: dts: qcom: Move clocks to CPU nodes
cpufreq: qcom-cpufreq-hw: Clocks are moved to CPU nodes
cpufreq: qcom-cpufreq-hw: Register config_clks helper

 .../bindings/cpufreq/cpufreq-qcom-hw.yaml     | 31 ++++----
 arch/arm64/boot/dts/qcom/sc7180.dtsi          | 19 ++++-
 arch/arm64/boot/dts/qcom/sc7280.dtsi          | 18 ++++-
 arch/arm64/boot/dts/qcom/sdm845.dtsi          | 19 ++++-
 arch/arm64/boot/dts/qcom/sm6350.dtsi          | 18 ++++-
 arch/arm64/boot/dts/qcom/sm8150.dtsi          | 19 ++++-
 arch/arm64/boot/dts/qcom/sm8250.dtsi          | 18 ++++-
 arch/arm64/boot/dts/qcom/sm8350.dtsi          | 19 ++++-
 arch/arm64/boot/dts/qcom/sm8450.dtsi          | 18 ++++-
 drivers/cpufreq/qcom-cpufreq-hw.c             | 75 ++++++++++++++-----
 10 files changed, 199 insertions(+), 55 deletions(-)

2.31.1.272.g89b43f80a514