Re: [PATCH v3 6/7] dt-bindings: soc: qcom: Extend RPMh power controller binding to describe thermal warming device

From: Ulf Hansson <ulf.hansson@linaro.org>
To: Thara Gopinath <thara.gopinath@linaro.org>
Cc: Eduardo Valentin <edubezval@gmail.com>,
	Zhang Rui <rui.zhang@intel.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Andy Gross <agross@kernel.org>,
	amit.kucheria@verdurent.com, Mark Rutland <mark.rutland@arm.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Linux PM <linux-pm@vger.kernel.org>,
	DTML <devicetree@vger.kernel.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 6/7] dt-bindings: soc: qcom: Extend RPMh power controller binding to describe thermal warming device
Date: Thu, 17 Oct 2019 17:43:08 +0200	[thread overview]
Message-ID: <CAPDyKFpYG7YADb6Xmm=8ug5=5X3d1y+JdkRvrnvtroeV3Yj62Q@mail.gmail.com> (raw)
In-Reply-To: <5DA88892.5000408@linaro.org>

On Thu, 17 Oct 2019 at 17:28, Thara Gopinath <thara.gopinath@linaro.org> wrote:
>
> Hello Ulf,
> Thanks for the review!
>
> On 10/17/2019 05:04 AM, Ulf Hansson wrote:
> > On Wed, 16 Oct 2019 at 21:37, Thara Gopinath <thara.gopinath@linaro.org> wrote:
> >>
> >> RPMh power controller hosts mx domain that can be used as thermal
> >> warming device. Add a sub-node to specify this.
> >>
> >> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> >> ---
> >>  Documentation/devicetree/bindings/power/qcom,rpmpd.txt | 10 ++++++++++
> >>  1 file changed, 10 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/power/qcom,rpmpd.txt b/Documentation/devicetree/bindings/power/qcom,rpmpd.txt
> >> index eb35b22..fff695d 100644
> >> --- a/Documentation/devicetree/bindings/power/qcom,rpmpd.txt
> >> +++ b/Documentation/devicetree/bindings/power/qcom,rpmpd.txt
> >> @@ -18,6 +18,16 @@ Required Properties:
> >>  Refer to <dt-bindings/power/qcom-rpmpd.h> for the level values for
> >>  various OPPs for different platforms as well as Power domain indexes
> >>
> >> += SUBNODES
> >> +RPMh alsp hosts power domains that can behave as thermal warming device.
> >> +These are expressed as subnodes of the RPMh. The name of the node is used
> >> +to identify the power domain and must therefor be "mx".
> >> +
> >> +- #cooling-cells:
> >> +       Usage: optional
> >> +       Value type: <u32>
> >> +       Definition: must be 2
> >> +
> >
> > Just wanted to express a minor thought about this. In general we use
> > subnodes of PM domain providers to represent the topology of PM
> > domains (subdomains), this is something different, which I guess is
> > fine.
> >
> > I assume the #cooling-cells is here tells us this is not a PM domain
> > provider, but a "cooling device provider"?
> Yep.
> >
> > Also, I wonder if it would be fine to specify "power-domains" here,
> > rather than using "name" as I think that is kind of awkward!?
> Do you mean "power-domain-names" ? I am using this to match against the
> genpd names defined in the provider driver.

No. If you are using "power-domains" it means that you allow to
describe the specifier for the provider.

From Linux point of view, it means you can use dev_pm_domain_attach()
to hook up the corresponding device with the PM domain.

Using "power-domain-names" is just to allow to specify a name rather
than an index, which makes sense if there is more than one index.
Perhaps you can state that the "power-domain-names" should be there
anyway, to be a little bit future proof if ever multiple index
(multiple PM domains).

Kind regards
Uffe