Currently the naming of a cooling device is just a cooling technique
followed by a number. When there are multiple cooling devices using
the same technique, it is impossible to clearly identify the related
device as this one is just a number.
For instance:
thermal-idle-0
thermal-idle-1
thermal-idle-2
thermal-idle-3
etc ...
The 'thermal' prefix is redundant with the subsystem namespace. This
patch removes the 'thermal prefix and changes the number by the device
name. So the naming above becomes:
idle-cpu0
idle-cpu1
idle-cpu2
idle-cpu3
etc ...
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20210314111333.16551-4-daniel.lezcano@linaro.org
Today, there is no user for the cpuidle cooling device. The targetted
platform is ARM and ARM64.
The cpuidle and the cpufreq cooling device are based on the device tree.
As the cpuidle cooling device can have its own configuration depending
on the platform and the available idle states. The DT node description
will give the optional properties to set the cooling device up.
Do no longer rely on the CPU node which is prone to error and will
lead to a confusion in the DT because the cpufreq cooling device is
also using it. Let initialize the cpuidle cooling device with the DT
binding.
This was tested on:
- hikey960
- hikey6220
- rock960
- db845c
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
Link: https://lore.kernel.org/r/20200429103644.5492-3-daniel.lezcano@linaro.org
The cpu idle cooling device offers a new method to cool down a CPU by
injecting idle cycles at runtime.
It has some similarities with the intel power clamp driver but it is
actually designed to be more generic and relying on the idle injection
powercap framework.
The idle injection duration is fixed while the running duration is
variable. That allows to have control on the device reactivity for the
user experience.
An idle state powering down the CPU or the cluster will allow to drop
the static leakage, thus restoring the heat capacity of the SoC. It
can be set with a trip point between the hot and the critical points,
giving the opportunity to prevent a hard reset of the system when the
cpufreq cooling fails to cool down the CPU.
With more sophisticated boards having a per core sensor, the idle
cooling device allows to cool down a single core without throttling
the compute capacity of several cpus belonging to the same clock line,
so it could be used in collaboration with the cpufreq cooling device.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20191219225317.17158-2-daniel.lezcano@linaro.org
