RE: [PATCH 2/2] arm64: dts: lx2160a: add device tree for lx2162aqds board

From: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
To: Shawn Guo <shawnguo@kernel.org>
Cc: "robh+dt@kernel.org" <robh+dt@kernel.org>,
	Varun Sethi <V.Sethi@nxp.com>, Leo Li <leoyang.li@nxp.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Ioana Ciornei <ioana.ciornei@nxp.com>,
	Kuldeep Singh <kuldeep.singh@nxp.com>
Subject: RE: [PATCH 2/2] arm64: dts: lx2160a: add device tree for lx2162aqds board
Date: Mon, 21 Sep 2020 13:34:06 +0000	[thread overview]
Message-ID: <AM7PR04MB6885E3EB822D59F2228DA4908E3A0@AM7PR04MB6885.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20200921130325.GA25428@dragon>

Ok, I will update the dts with your suggestions.

Thanks,
Meenakshi

> -----Original Message-----
> From: Shawn Guo <shawnguo@kernel.org>
> Sent: Monday, September 21, 2020 6:33 PM
> To: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
> Cc: robh+dt@kernel.org; Varun Sethi <V.Sethi@nxp.com>; Leo Li
> <leoyang.li@nxp.com>; linux-arm-kernel@lists.infradead.org;
> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Ioana Ciornei
> <ioana.ciornei@nxp.com>; Kuldeep Singh <kuldeep.singh@nxp.com>
> Subject: Re: [PATCH 2/2] arm64: dts: lx2160a: add device tree for lx2162aqds
> board
> 
> On Mon, Sep 21, 2020 at 06:00:53AM +0000, Meenakshi Aggarwal wrote:
> >
> >
> > > -----Original Message-----
> > > From: Shawn Guo <shawnguo@kernel.org>
> > > Sent: Saturday, September 12, 2020 3:19 PM
> > > To: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
> > > Cc: robh+dt@kernel.org; Varun Sethi <V.Sethi@nxp.com>; Leo Li
> > > <leoyang.li@nxp.com>; linux-arm-kernel@lists.infradead.org;
> > > devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Ioana
> > > Ciornei <ioana.ciornei@nxp.com>; Kuldeep Singh
> > > <kuldeep.singh@nxp.com>
> > > Subject: Re: [PATCH 2/2] arm64: dts: lx2160a: add device tree for
> > > lx2162aqds board
> > >
> > > On Wed, Sep 09, 2020 at 07:10:12AM +0000, Meenakshi Aggarwal wrote:
> > > > > > +	sb_3v3: regulator-sb3v3 {
> > > > > > +		compatible = "regulator-fixed";
> > > > > > +		regulator-name = "MC34717-3.3VSB";
> > > > > > +		regulator-min-microvolt = <3300000>;
> > > > > > +		regulator-max-microvolt = <3300000>;
> > > > > > +		regulator-boot-on;
> > > > > > +		regulator-always-on;
> > > > >
> > > > > I do not see any point to have regulator-boot-on or
> > > > > regulator-always-on for a regulator that doesn't have on/off control.
> > > > [Meenakshi Aggarwal] Properties are added to specify that platform
> > > > firmware's out of reset configuration enabled the regulator and
> > > > regulator
> > > should never be disabled or change its operative status.
> > >
> > > What I was wondering if how this regulator is enabled by firmware,
> > > by some GPIO control?  In that case, 'gpio' property should be there
> > > to describe the GPIO control.
> > >
> > [Meenakshi Aggarwal] Its not controlled by GPIO. Its gets power on with board.
> > > >
> > > > Can you help in understanding why these optional properties cannot
> > > > be used together
> > >
> > > It's totally fine to use these properties together.  But if the
> > > regulator doesn't have on/off control, neither of them makes sense.
> > [Meenakshi Aggarwal] As per documentation, we should keep "
> > regulator-always-on " as per description, we Can remove " regulator-boot-on"
> property from dts.
> >
> > regulator-always-on:
> >     description: boolean, regulator should never be disabled
> 
> Again, the property is only meaningful for a regulator that can possibly be
> disabled.
> 
> Shawn