linux-kernel - Re: [PATCH 2/2] dt-bindings: mfd: cros-ec: add properties for thermal cooling cells

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Message-ID: <Z0Q2_ds3HCMaN1jQ@google.com>
Date: Mon, 25 Nov 2024 16:36:13 +0800
From: "Sung-Chi, Li" <lschyi@...omium.org>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: Benson Leung <bleung@...omium.org>, Guenter Roeck <groeck@...omium.org>,
	Sebastian Reichel <sre@...nel.org>, Lee Jones <lee@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, chrome-platform@...ts.linux.dev,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org
Subject: Re: [PATCH 2/2] dt-bindings: mfd: cros-ec: add properties for
 thermal cooling cells

On Mon, Nov 25, 2024 at 08:35:01AM +0100, Krzysztof Kozlowski wrote:
> On 25/11/2024 08:32, Krzysztof Kozlowski wrote:
> > On 25/11/2024 03:50, Sung-Chi, Li wrote:
> >> On Fri, Nov 22, 2024 at 08:49:14AM +0100, Krzysztof Kozlowski wrote:
> >>> On Fri, Nov 22, 2024 at 11:47:22AM +0800, Sung-Chi Li wrote:
> >>>> The cros_ec supports limiting the input current to act as a passive
> >>>> thermal cooling device. Add the property '#cooling-cells' bindings, such
> >>>> that thermal framework can recognize cros_ec as a valid thermal cooling
> >>>> device.
> >>>>
> >>>> Signed-off-by: Sung-Chi Li <lschyi@...omium.org>
> >>>> ---
> >>>>  Documentation/devicetree/bindings/mfd/google,cros-ec.yaml | 3 +++
> >>>>  1 file changed, 3 insertions(+)
> >>>>
> >>>> diff --git a/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml b/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
> >>>> index aac8819bd00b..2b6f098057af 100644
> >>>> --- a/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
> >>>> +++ b/Documentation/devicetree/bindings/mfd/google,cros-ec.yaml
> >>>> @@ -96,6 +96,9 @@ properties:
> >>>>    '#gpio-cells':
> >>>>      const: 2
> >>>>  
> >>>> +  '#cooling-cells':
> >>>> +    const: 2
> >>>
> >>> This is not a cooling device. BTW, your commit msg is somehow circular.
> 
> 
> ^^^ And here which you ignored: this is not a cooling device.
> 

Hi, I added the explanation in the commit message in the v2 version. Please have
a look, it should explains why it is not a cooling device.

> >>> "Add cooling to make it a cooling device because it will be then cooling
> >>> device."
> >>>
> >>> Power supply already provides necessary framework for managing charging
> >>> current and temperatures. If this is to stay, you need to explain why
> >>> this is suitable to be considered a thermal zone or system cooling
> >>> device (not power supply or input power cooling).
> >>>
> >>> Best regards,
> >>> Krzysztof
> >>>
> >>
> >> Thank you, I will rephrase the commit message. The reason to not to use the
> >> managing charging current and temperatures in the power supply framework is
> >> that:
> >>
> >> - The EC may not have the thermal sensor value for the charger, and there is no
> >>   protocol for getting the thermal sensor value for the charger (there is
> >>   command for reading thermal sensor values, but there is no specification for
> >>   what sensor index is for the charger, if the charger provides thermal value).
> >> - The managing mechanism only take the charger thermal value into account, and
> >>   I would like to control the current based on the thermal condition of the
> >>   whole device.
> >>
> >> I will include these explanation in the following changes.
> > 
> > 
> > This does not explain me why this is supposed to be thermal zone. I
> > already said it, but let's repeat: This is not a thermal zone. This
> > isn't thermal zone sensor, either.
> 
> 
> And nothing from your "revised" commit msg explains why something which
> is not a cooling device is supposed to be a cooling device.

The revised commit message is sent, please have a look.

> 
> 
> Best regards,
> Krzysztof