linux-kernel - RE: [PATCH 2/5] dt-bindings: mfd: da9062: add regulator voltage selection documentation

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Date:   Wed, 25 Sep 2019 16:18:59 +0000
From:   Adam Thomson <Adam.Thomson.Opensource@...semi.com>
To:     Marco Felsch <m.felsch@...gutronix.de>,
        Adam Thomson <Adam.Thomson.Opensource@...semi.com>
CC:     Support Opensource <Support.Opensource@...semi.com>,
        "lee.jones@...aro.org" <lee.jones@...aro.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        Steve Twiss <stwiss.opensource@...semi.com>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 2/5] dt-bindings: mfd: da9062: add regulator voltage
 selection documentation

On 25 September 2019 16:52, Marco Felsch wrote:

> Hi Adam,
> 
> On 19-09-24 09:23, Adam Thomson wrote:
> > On 17 September 2019 13:43, Marco Felsch wrote:
> >
> > > Add the documentation which describe the voltage selection gpio support.
> > > This property can be applied to each subnode within the 'regulators'
> > > node so each regulator can be configured differently.
> > >
> > > Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
> > > ---
> > >  Documentation/devicetree/bindings/mfd/da9062.txt | 9 +++++++++
> > >  1 file changed, 9 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/mfd/da9062.txt
> > > b/Documentation/devicetree/bindings/mfd/da9062.txt
> > > index edca653a5777..9d9820d8177d 100644
> > > --- a/Documentation/devicetree/bindings/mfd/da9062.txt
> > > +++ b/Documentation/devicetree/bindings/mfd/da9062.txt
> > > @@ -66,6 +66,15 @@ Sub-nodes:
> > >    details of individual regulator device can be found in:
> > >    Documentation/devicetree/bindings/regulator/regulator.txt
> > >
> > > +  Optional regulator device-specific properties:
> > > +  - dlg,vsel-sense-gpios : The GPIO reference which should be used by the
> > > +    regulator to switch the voltage between active/suspend voltage settings.
> If
> > > +    the signal is active the active-settings are applied else the suspend
> > > +    settings are applied. Attention: Sharing the same gpio for other purposes
> > > +    or across multiple regulators is possible but the gpio settings must be the
> > > +    same. Also the gpio phandle must refer to to the dlg,da9062-gpio device
> > > +    other gpios are not allowed and make no sense.
> > > +
> >
> > Should we not use the binding names that are defined in 'gpio-regulator.yaml'
> as
> > these seem to be generic and would probably serve the purpose here?
> 
> Hm.. as the description says:
> 
> 8<--------------------------------------------------
> gpios:
>    description: Array of one or more GPIO pins used to select the
>    regulator voltage/current listed in "states".
> 8<--------------------------------------------------
> 
> But we don't have a "states" property and we can't select between
> voltage or current.

Yes I think I was at cross purposes when I made this remark. The bindings there
describe the GPOs that are used to enable/disable and set voltage/current for
regulators and the supported voltage/current levels that can be configured in
this manner. What you're describing is the GPI for DA9061/2. If you look at
GPIO handling in existing regulator drivers I believe they all deal with external
GPOs that are configured to enable/disable and set voltage/current limits rather
than the GPI on the PMIC itself. That's why I'm thinking that the configurations
you're doing here should actually be in a pinctrl or GPIO driver.

I'd be interested in hearing Mark's view on this though as he has far more
experience in this area than I do.

> 
> Regards,
>   Marco
> 
> > >  - rtc : This node defines settings required for the Real-Time Clock associated
> > >    with the DA9062. There are currently no entries in this binding, however
> > >    compatible = "dlg,da9062-rtc" should be added if a node is created.
> > > --
> > > 2.20.1
> >
> >
> 
> --
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