linux-kernel - Re: [PATCH] ARM: dts: am335x: Add rtc node as system-power-controller

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Message-ID: <20211016050406.GA575510@x1>
Date:   Fri, 15 Oct 2021 22:04:06 -0700
From:   Drew Fustini <dfustini@...libre.com>
To:     Jason Kridner <jkridner@...gleboard.org>
Cc:     Johan Hovold <johan@...nel.org>,
        Benoit Cousson <bcousson@...libre.com>,
        Dave Gerlach <d-gerlach@...com>, Keerthy <j-keerthy@...com>,
        Tony Lindgren <tony@...mide.com>,
        Rob Herring <robh+dt@...nel.org>,
        OMAP List <linux-omap@...r.kernel.org>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: dts: am335x: Add rtc node as system-power-controller

On Thu, Oct 14, 2021 at 10:12:48AM -0400, Jason Kridner wrote:
> On Thu, Oct 14, 2021 at 6:43 AM Johan Hovold <johan@...nel.org> wrote:
> 
> > On Wed, Oct 13, 2021 at 02:41:03PM -0700, Drew Fustini wrote:
> > > On Wed, Oct 13, 2021 at 09:23:42AM +0200, Johan Hovold wrote:
> > > > On Tue, Oct 12, 2021 at 12:13:12PM -0700, Drew Fustini wrote:
> > > > > From: Keerthy <j-keerthy@...com>
> > > > >
> > > > > PMIC_PWR_EN pin of RTC on am335x-evm, bone, and boneblack is
> > connected to
> > > > > PMIC on board, so flag rtc node as system-power-controller to allow
> > > > > software to poweroff boards.
> > > >
> > > > The "system-power-controller" property is already set in
> > > > bone-common.dtsi since
> > > >
> > > >     2876cc4a773c ("ARM: dts: Move most of am335x-boneblack.dts to
> > am335x-boneblack-common.dtsi")
> > > >
> > > > so this probably only affects am335x-evm and that should be reflected
> > in
> > > > the commit message.
> > > >
> > > > Also, should you now remove the property from boneblack-common? Or just
> > > > add it to am335x-evm instead?
> > >
> > > Thank you for reviewing. Yes, I should improve the commit message as the
> > > BeagleBone Black is already covered for the rtc system-power-controller
> > > in am335x-boneblack-common.dtsi.
> >
> > So is sancloud-bbe apparently.
> >
> > I only noticed because I added support to BeagleBone Black long ago so
> > unless there'd been a regression it should already be supported.
> >
> > > I believe it would be ok to remove system-power-controller from
> > > am335x-boneblack-common.dtsi and have it in am335x-bone-common.dtsi.
> > >
> > > These are the files that include am335x-boneblack-common.dtsi:
> > > arch/arm/boot/dts/am335x-boneblack-wireless.dts
> > > arch/arm/boot/dts/am335x-boneblack.dts
> > > arch/arm/boot/dts/am335x-sancloud-bbe-lite.dts
> > > arch/arm/boot/dts/am335x-sancloud-bbe.dts
> > >
> > > But they all also include am335x-bone-common.dtsi.
> > >
> > > However, I just noticed that am335x-evm.dts does not include either
> > > am335x-boneblack-common.dtsi or am335x-boneblack-common.dtsi. Thus
> > > rtc system-power-controller should be directly inserted into
> > > am335x-evm.dts.
> >
> > Right.
> >
> > > I considered just moving system-power-controller to the rtc node in
> > > am33xx-l4.dtsi but I don't think that would be correct as this would not
> > > be valid for all am33xx devices.
> > >
> > > Does that seem correct to you?
> >
> > No, that wouldn't be right.
> >
> > You're more familiar with the different variants here, but unless all
> > flavours of Bone Black have the signal wired, it should probably be
> > pushed down into the dts files again.
> >
> 
> I believe anything "bone" is going to have the same RTC power
> configuration. I believe this could be inconsistent at the AM335x level.

Thanks for the input Jason and Johan.

These are the dts files that currently include either 
am335x-bone-common.dtsi or am335x-boneblack-common.dtsi:

    am335x-bone.dts  
	am335x-bone-common.dtsi

    am335x-boneblack.dts
        am335x-bone-common.dtsi
	am335x-boneblack-common.dtsi [rtc system-power-controller]

    am335x-boneblack-wireless.dts
	am335x-bone-common.dtsi
	am335x-boneblack-common.dtsi [rtc system-power-controller]

    am335x-bonegreen.dts
	am335x-bone-common.dtsi

    am335x-bonegreen-wireless.dts
	am335x-bone-common.dtsi

    am335x-sancloud-bbe.dts
	am335x-bone-common.dtsi
	am335x-boneblack-common.dtsi [rtc system-power-controller]

    am335x-sancloud-bbe-lite.dts
	am335x-bone-common.dtsi
	am335x-boneblack-common.dtsi [rtc system-power-controller]

am335x-boneblack.dts, am335x-boneblack-wireless.dts,
am335x-sancloud-bbe.dts, and am335x-sancloud-bbe-lite.dts already have
the rtc system-power-controller through am335x-boneblack-common.dtsi.

Moving rtc system-power-controller from am335x-boneblack-common.dtsi to
am335x-bone-common.dtsi would have no change for those boards as they
also include am335x-bone-common.dtsi.

It would add system-power-controller to am335x-bone.dts,
am335x-bonegreen.dts, and am335x-bonegreen-wireless.dts.

The original bone, green and green wireless have PMIC_POWR_EN (ZCZ C6)
connected to PWR_EN on the TPS65217B PMIC. Thus system-power-controller
should be valid for them too.

I will make new patch series that:

  * removes system-power-controller from am335x-boneblack-common.dtsi 
  * adds system-power-controller to am335x-bone-common.dtsi
  * adds system-power-controller to am335x-evm.dts, am335x-icev2.dts,
    am335x-icev2-prueth.dts

However, am335x-evmsk.dts should not have system-power-controller as
PMIC_POWR_EN is not connected in that board design.

Thanks,
Drew