Re: [PATCH 0/4] qcom: Model RPMH power domains as thermal cooling devices

[Daniel Lezcano <daniel.lezcano@linaro.org>]

Hi Thara,

interesting series. Can you describe what use case this series will solve?

On 10/08/2019 02:58, Thara Gopinath wrote:
> Certain RPMH power domains can be used to warm up the SoC (mx on sdm845)
> if the temperature falls below certain threshold. 

What is the relationship between the temperature fall, the sensor(s)
location and the warming device(s) in this case?


> These power domains
> can be considered as thermal warming devices
> (opposite of thermal cooling devices).

Is it possible to elaborate how works the RPMH as a warming device and
what is the "mx on sdm845"?

> In kernel, these warming devices can be modeled as a 
> thermal cooling device. To use these power domains as warming devices
> require further tweaks in the thermal framework which are out of scope
> of this patch series.
> 
> The first patch in this series extends the genpd framework to export out
> the performance states of a power domain so that when the RPMH power
> domain is modeled as a cooling device, the number of possible states and
> current state of the cooling device can be retrieved from the genpd
> framework.
> 
> The second patch implements the newly added genpd callback for RPMH power
> domain driver.
> 
> The third patch implements the modeling of a RPMH power domain as
> a cooling device and the final patch adds the device node entry for sdm845
> to consider RPMHPD MX a cooling device.
> 
> Thara Gopinath (4):
>   PM/Domains: Add support for retrieving genpd performance states
>     information
>   soc: qcom: rpmhpd: Introduce function to retrieve power domain
>     performance state count
>   thermal: qcom: Add RPMHPD cooling device driver.
>   arm64: dts: qcom: Extend AOSS RPMHPD node
> 
>  arch/arm64/boot/dts/qcom/sdm845.dtsi    |   7 ++
>  drivers/base/power/domain.c             |  38 +++++++++
>  drivers/soc/qcom/rpmhpd.c               |  11 +++
>  drivers/thermal/qcom/Kconfig            |   7 ++
>  drivers/thermal/qcom/Makefile           |   1 +
>  drivers/thermal/qcom/qcom-rpmhpd-cdev.c | 141 ++++++++++++++++++++++++++++++++
>  include/linux/pm_domain.h               |  18 ++++
>  7 files changed, 223 insertions(+)
>  create mode 100644 drivers/thermal/qcom/qcom-rpmhpd-cdev.c
> 


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