Re: [PATCH v2 10/10] arm64: dts: Create SoC thermal zone for Juno

Punit Agrawal
2015-08-14T12:38:50Z

[ adding Eduardo, Rui for their take on OF-thermal bindings ]

Punit Agrawal <punit.agrawal@arm.com> writes:

> Hi Liviu,
>
> Thanks for having a look.
>
> Liviu Dudau <Liviu.Dudau@arm.com> writes:
>
>> On Mon, Aug 03, 2015 at 04:22:58PM +0100, Punit Agrawal wrote:
>>> Setup a thermal zone driven by the SoC temperature sensor on Juno
>>> r0. Create passive trip points and bind them to cpufreq cooling
>>> devices that support the power extensions.
>>
>> Hi Punit,
>>
>>>
>>> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
>>> Cc: Rob Herring <robh+dt@kernel.org>
>>> Cc: Mark Rutland <mark.rutland@arm.com>
>>> Cc: Liviu Dudau <liviu.dudau@arm.com>
>>> Cc: Sudeep Holla <sudeep.holla@arm.com>
>>> ---
>>> arch/arm64/boot/dts/arm/juno.dts | 50 ++++++++++++++++++++++++++++++++++++++++
>>> 1 file changed, 50 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/arm/juno.dts b/arch/arm64/boot/dts/arm/juno.dts
>>> index d2e67f3..664961c 100644
>>> --- a/arch/arm64/boot/dts/arm/juno.dts
>>> +++ b/arch/arm64/boot/dts/arm/juno.dts
>>> @@ -9,6 +9,7 @@
>>> /dts-v1/;
>>>
>>> #include <dt-bindings/interrupt-controller/arm-gic.h>
>>> +#include <dt-bindings/thermal/thermal.h>
>>>
>>> / {
>>> model = "ARM Juno development board (r0)";
>>> @@ -90,6 +91,8 @@
>>> next-level-cache = <&A57_L2>;
>>> clocks = <&scpi_dvfs 0>;
>>> cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
>>> + #cooling-cells = <2>;
>>> + dynamic-power-coefficient = <530>;
>>
>> The Documentation/devicetree/bindings/thermal/thermal.txt document describes two additional
>> required properties, cooling-min-state and cooling-max-state which are missing here.
>>
>
> The bindings do suggest that the cooling-*-state are required but I
> couldn't find any code making use of this property.
>
> I'll send a patch with the next version making those properties
> optional.
>

On second thoughts...

The question about cooling-*-state has come up in another thread as
well [0]. I'll re-iterate the question for the thermal maintainers to
clarify.

The cooling-{max,min}-state properties are marked mandatory in the
bindings but aren't used in the code anywhere. Can we drop those
properties from the binding documentation? Or at the least, make them optional?

[...]

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