[EXT] Re: [PATCH v6 5/5] arm64: dts: freescale: add support for i.MX8DXL EVK board

[Shenwei Wang]

> -----Original Message-----
> From: Shawn Guo <shawnguo at kernel.org>
> Sent: Monday, September 12, 2022 9:07 PM
> To: Shenwei Wang <shenwei.wang at nxp.com>
> Cc: Rob Herring <robh+dt at kernel.org>; Krzysztof Kozlowski
> <krzysztof.kozlowski+dt at linaro.org>; Sascha Hauer <s.hauer at pengutronix.de>;
> Pengutronix Kernel Team <kernel at pengutronix.de>; Peng Fan
> <peng.fan at nxp.com>; devicetree at vger.kernel.org; linux-arm-
> kernel at lists.infradead.org; imx at lists.linux.dev; dl-linux-imx <linux-
> imx at nxp.com>
> Subject: Re: [EXT] Re: [PATCH v6 5/5] arm64: dts: freescale: add support for
> i.MX8DXL EVK board
> 
> Caution: EXT Email
> 
> On Mon, Sep 12, 2022 at 02:35:18PM +0000, Shenwei Wang wrote:
> >
> >
> > > -----Original Message-----
> > > From: Shawn Guo <shawnguo at kernel.org>
> > > Sent: Monday, September 12, 2022 3:17 AM
> > > To: Shenwei Wang <shenwei.wang at nxp.com>
> > > Cc: Rob Herring <robh+dt at kernel.org>; Krzysztof Kozlowski
> > > <krzysztof.kozlowski+dt at linaro.org>; Sascha Hauer
> > > <s.hauer at pengutronix.de>; Pengutronix Kernel Team
> > > <kernel at pengutronix.de>; Peng Fan <peng.fan at nxp.com>;
> > > devicetree at vger.kernel.org; linux-arm- kernel at lists.infradead.org;
> > > imx at lists.linux.dev; dl-linux-imx <linux- imx at nxp.com>
> > > > > > +
> > > > > > +     reg_fec1_sel: regulator-1 {
> > > > > > +             compatible = "regulator-fixed";
> > > > > > +             regulator-name = "fec1_supply";
> > > > > > +             regulator-min-microvolt = <3300000>;
> > > > > > +             regulator-max-microvolt = <3300000>;
> > > > > > +             gpio = <&pca6416_1 11 GPIO_ACTIVE_HIGH>;
> > > > >
> > > > > Missing enable-active-high?
> > > >
> > > > No. Enabling this regulator to select the fec1 interface instead of usdhc2.
> > > Pulling this GPIO pin to low is to use FEC1 interface.
> > >
> > > Then the polarity cell should be GPIO_ACTIVE_LOW rather than
> > > GPIO_ACTIVE_HIGH?
> > >
> >
> > That doesn't matter since any GPIO phandle flags are ignored in the node of
> "regulator-fixed".  The final flag is only determined by the property of "enable-
> active-high".  If there is a "enable-active-high", the GPIO line works as active
> high. If no such a property, it works as active low by default. Right?
> >
> 
> Well, we are talking about the correctness of DT (hardware description), not
> how kernel driver works with DT.
> 

So the correct syntax here is: if enable-active-high is used, the flag of gpio phandle should also be configured as "ACTIVE_HIGH". Otherwise, if no enable-active-high, the GPIO flag should be "ACTIVE_LOW".  Is my understanding correct?

Regards,
Shenwei

> Shawn