linux-kernel - Re: [PATCH v1 2/3] dt-binding: power: power-domain: add power-supply-needs-irq

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Date:   Tue, 12 Jul 2022 14:24:08 +0200
From:   Martin Kepplinger <martin.kepplinger@...i.sm>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        rafael@...nel.org, khilman@...nel.org, ulf.hansson@...aro.org,
        robh@...nel.org, shawnguo@...nel.org, s.hauer@...gutronix.de,
        festevam@...il.com, pavel@....cz
Cc:     kernel@...i.sm, linux-imx@....com, broonie@...nel.org,
        l.stach@...gutronix.de, aford173@...il.com,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v1 2/3] dt-binding: power: power-domain: add
 power-supply-needs-irq

Am Dienstag, dem 12.07.2022 um 09:01 +0200 schrieb Krzysztof Kozlowski:
> On 11/07/2022 15:17, Martin Kepplinger wrote:
> > Am Montag, dem 11.07.2022 um 12:38 +0200 schrieb Krzysztof
> > Kozlowski:
> > > On 11/07/2022 11:45, Martin Kepplinger wrote:
> > > > Add the power-supply-needs-irq board description property for
> > > > power
> > > > domains.
> > > 
> > > Where is a board description here? I think you just meant
> > > "power-supply-needs-irq property"?
> > > > 
> > > > Signed-off-by: Martin Kepplinger <martin.kepplinger@...i.sm>
> > > > ---
> > > >  .../devicetree/bindings/power/power-domain.yaml        | 10
> > > > ++++++++++
> > > >  1 file changed, 10 insertions(+)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/power/power-
> > > > domain.yaml b/Documentation/devicetree/bindings/power/power-
> > > > domain.yaml
> > > > index 889091b9814f..e82c2f7ccb97 100644
> > > > --- a/Documentation/devicetree/bindings/power/power-domain.yaml
> > > > +++ b/Documentation/devicetree/bindings/power/power-domain.yaml
> > > > @@ -70,6 +70,16 @@ properties:
> > > >        by the given provider should be subdomains of the domain
> > > > specified
> > > >        by this binding.
> > > >  
> > > > +  power-supply: true
> > > 
> > > This is a new property not described in the commit msg.
> > 
> > true, I think it's missing and could be added as a separate patch.
> > 
> > > 
> > > > +
> > > > +  power-supply-needs-irq:
> > > > +    type: boolean
> > > > +    description:
> > > > +      A power-supply can link for example to a regulator
> > > > controlled via
> > > > +      i2c or otherwise needing interrupts enabled to be able
> > > > to
> > > > enable and
> > > > +      disable. 
> > > 
> > > Not really a property of power domain. How the regulator supply
> > > works
> > > is
> > > entirely up to regulator. Otherwise such property should appear
> > > for
> > > every device.
> > 
> > you're right. The power-domain driver could read the power-supply
> > regulator node directly. Still, I think then a new regulator
> > property
> > is needed instead, or is it?
> 
> In case of regulator, I am not so sure it needs a dedicated property
> of
> DT. If it is I2C regulator - the parent node is I2C bus and regulator
> device is some child of I2C controller (could be via a MFD device),
> so
> no need for dedicated property.
> 
> If it uses interrupts, then:
> 1. The presence of interrupts is already known - "interrupts"
> property.
> 2. The actual use of interrupts is DT independent and only driver
> knows it.

thanks for this great suggestion! for the imx8mq devices this (1.)
indeed is the case for exactly the 3 regulators I manually describe
here. v2 of this patch looks very elegant (and I guess I could have
removed the DT people from the email, I forgot). here it is:

https://lore.kernel.org/linux-arm-kernel/20220712121832.3659769-1-martin.kepplinger@puri.sm/T/#u

> 
> Best regards,
> Krzysztof