linux-kernel - Re: [PATCH v2 1/3] ARM: dts: Add cooling levels for CPUs on exynos5420

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Date:	Mon, 22 Feb 2016 11:21:37 +0000
From:	Punit Agrawal <punit.agrawal@....com>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Cc:	devicetree@...r.kernel.org,
	Lukasz Majewski <l.majewski@...sung.com>,
	linux-samsung-soc@...r.kernel.org, linux-pm@...r.kernel.org,
	Viresh Kumar <viresh.kumar@...aro.org>,
	linux-kernel@...r.kernel.org,
	Eduardo Valentin <edubezval@...il.com>,
	Kukjin Kim <kgene@...nel.org>, Zhang Rui <rui.zhang@...el.com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 1/3] ARM: dts: Add cooling levels for CPUs on exynos5420

Krzysztof Kozlowski <k.kozlowski@...sung.com> writes:

> On 19.02.2016 02:58, Punit Agrawal wrote:
>> Hi Krzysztof,
>> 
>> Krzysztof Kozlowski <k.kozlowski@...sung.com> writes:
>> 
>>> On Exynos5420 we support 8 cpufreq steps (600-1300 MHz) for LITTLE and
>>> 12 steps for big core (700-1800 MHz). Add respective cooling cells.
>>>
>>> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
>>>
>>> ---
>>>
>>> Changes since v1:
>>> 1. Add cooling properties to all CPUs (suggested by Viresh).
>>> ---
>>>  arch/arm/boot/dts/exynos5420-cpus.dtsi | 24 ++++++++++++++++++++++++
>>>  1 file changed, 24 insertions(+)
>>>
>>> diff --git a/arch/arm/boot/dts/exynos5420-cpus.dtsi b/arch/arm/boot/dts/exynos5420-cpus.dtsi
>>> index 261d25173f61..5c052d7ff554 100644
>>> --- a/arch/arm/boot/dts/exynos5420-cpus.dtsi
>>> +++ b/arch/arm/boot/dts/exynos5420-cpus.dtsi
>>> @@ -33,6 +33,9 @@
>>>  			clock-frequency = <1800000000>;
>>>  			cci-control-port = <&cci_control1>;
>>>  			operating-points-v2 = <&cluster_a15_opp_table>;
>>> +			cooling-min-level = <0>;
>>> +			cooling-max-level = <11>;
>> 
>> Although the above two properties are defined they aren't parsed in the
>> kernel.
>> 
>> Setting min / max extents for cooling devices via cooling maps does work
>> though.
>
> It is described as optional property in
> Documentation/devicetree/bindings/thermal/thermal.txt ... but indeed it
> is totally ignored.
>
> So what is the recommendation? Get rid of it from DTS and documentation
> or leave it because it will be implemented someday?

As long as you are not expecting any particular behaviour arising from
that property today I think it should be fine to leave it in.

Eduardo, do you agree?

>
> Thanks for feedback!
>
> Best regards,
> Krzysztof
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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