From: Thara Gopinath <thara.gopinath@linaro.org>
To: Rob Herring <robh@kernel.org>, Ulf Hansson <ulf.hansson@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 <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: Wed, 30 Oct 2019 10:27:42 -0400 [thread overview]
Message-ID: <5DB99DDE.3090308@linaro.org> (raw)
In-Reply-To: <CAL_Jsq+OoyC5FZxYrX_KN1QLDXRvKuFbH=9pLiELsOtoPixnPA@mail.gmail.com>
Hi Rob,
Thanks for the review.
On 10/29/2019 04:16 PM, Rob Herring wrote:
> On Tue, Oct 29, 2019 at 5:07 AM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>>
>> On Tue, 29 Oct 2019 at 02:36, Rob Herring <robh@kernel.org> wrote:
>>>
>>> On Thu, Oct 17, 2019 at 12:10:15PM -0400, Thara Gopinath wrote:
>>>> On 10/17/2019 11:43 AM, Ulf Hansson wrote:
>>>>> 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.
>>>> Yep. But won't this look funny in DT ? The provider node will have a sub
>>>> node with a power domain referencing to itself Like below: Is this ok ?
>>>>
>>>> rpmhpd: power-controller {
>>>> compatible = "qcom,sdm845-rpmhpd";
>>>> #power-domain-cells = <1>;
>>>>
>>>> ...
>>>> ...
>>>> mx_cdev: mx {
>>>> #cooling-cells = <2>;
>>>> power-domains = <&rpmhpd SDM845_MX>;
>>>> };
>>>>
>>>
>>> The whole concept here seems all wrong to me. Isn't it what's in the
>>> power domain that's the cooling device. A CPU power domain is not a
>>> cooling device, the CPU is. Or we wouldn't make a clock a cooling
>>> device, but what the clock drives.
>>
>> Well, I don't think that's entirely correct description either.
>>
>> As I see it, it's really the actual PM domain (that manages voltages
>> for a power island), that needs to stay in full power state and
>> increase its voltage level, as to warm up some of the silicon. It's
>> not a regular device, but more a characteristics of how the PM domain
>> can be used.
>
> First I've heard of Si needing warming...
Cold regions and non-closing of circuits is what I am told.
>
> I think I'd just expect the power domain provider to know which
> domains to power on then.
I will just retain #cooling-cells in the power domain provider and let
the driver identify the actual power domains.
>
> Rob
>
--
Warm Regards
Thara
next prev parent reply other threads:[~2019-10-30 14:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1571254641-13626-1-git-send-email-thara.gopinath@linaro.org>
[not found] ` <1571254641-13626-8-git-send-email-thara.gopinath@linaro.org>
2019-10-29 1:31 ` [PATCH v3 7/7] arm64: dts: qcom: Add mx power domain as thermal warming device Rob Herring
2019-10-30 14:23 ` Thara Gopinath
[not found] ` <1571254641-13626-7-git-send-email-thara.gopinath@linaro.org>
[not found] ` <CAPDyKFqcKfmnNJ7j4Jb+JH739FBcHg5NBD6aR4H_N=zWGwm1ww@mail.gmail.com>
[not found] ` <5DA88892.5000408@linaro.org>
[not found] ` <CAPDyKFpYG7YADb6Xmm=8ug5=5X3d1y+JdkRvrnvtroeV3Yj62Q@mail.gmail.com>
[not found] ` <5DA89267.30806@linaro.org>
2019-10-29 1:36 ` [PATCH v3 6/7] dt-bindings: soc: qcom: Extend RPMh power controller binding to describe " Rob Herring
2019-10-29 10:06 ` Ulf Hansson
2019-10-29 20:16 ` Rob Herring
2019-10-30 9:27 ` Ulf Hansson
2019-10-30 14:27 ` Thara Gopinath [this message]
[not found] ` <1571254641-13626-4-git-send-email-thara.gopinath@linaro.org>
2019-12-03 17:04 ` [PATCH v3 3/7] thermal: core: Add late init hook to cooling device ops Amit Kucheria
2019-12-03 17:09 ` Thara Gopinath
2019-12-03 17:11 ` Amit Kucheria
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5DB99DDE.3090308@linaro.org \
--to=thara.gopinath@linaro.org \
--cc=agross@kernel.org \
--cc=amit.kucheria@verdurent.com \
--cc=bjorn.andersson@linaro.org \
--cc=daniel.lezcano@linaro.org \
--cc=devicetree@vger.kernel.org \
--cc=edubezval@gmail.com \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=rjw@rjwysocki.net \
--cc=robh@kernel.org \
--cc=rui.zhang@intel.com \
--cc=ulf.hansson@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).