Re: [PATCH v1 1/7] arm64: dts: imx8dxl-evk: Add vpcie3v3aux regulator for PCIe M.2 connector

Frank Li
2025-11-11T16:11:28Z

On Tue, Nov 11, 2025 at 08:02:20AM +0000, Hongxing Zhu wrote:
> > -----Original Message-----
> > From: Shawn Guo <shawnguo2@yeah.net>
> > Sent: 2025年11月11日 15:37
> > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > Cc: robh@kernel.org; krzk+dt@kernel.org; conor+dt@kernel.org;
> > shawnguo@kernel.org; Frank Li <frank.li@nxp.com>;
> > s.hauer@pengutronix.de; festevam@gmail.com; kernel@pengutronix.de;
> > devicetree@vger.kernel.org; imx@lists.linux.dev;
> > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH v1 1/7] arm64: dts: imx8dxl-evk: Add vpcie3v3aux
> > regulator for PCIe M.2 connector
> >
> > On Fri, Oct 24, 2025 at 03:31:46PM +0800, Richard Zhu wrote:
> > > Refer to PCI Express M.2 Specification r5.1 sec3.1.1 Power Sources and
> > > Grounds.
> > >
> > > PCI Express M.2 Socket 1 utilizes a 3.3 V power source. The voltage
> > > source, 3.3 V, is expected to be available during the system’s
> > > stand-by/suspend state to support wake event processing on the
> > > communications card.
> > >
> > > Add vpcie3v3aux regulator to let this 3.3 V power source always on for
> > > PCIe M.2 Key E connector on i.MX8DXL EVK board.
> > >
> > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > ---
> > > arch/arm64/boot/dts/freescale/imx8dxl-evk.dts | 1 +
> > > 1 file changed, 1 insertion(+)
> > >
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8dxl-evk.dts
> > > b/arch/arm64/boot/dts/freescale/imx8dxl-evk.dts
> > > index 25a77cac6f0b5..7704dba9e37c0 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8dxl-evk.dts
> > > +++ b/arch/arm64/boot/dts/freescale/imx8dxl-evk.dts
> > > @@ -649,6 +649,7 @@ &pcie0 {
> > > pinctrl-names = "default";
> > > reset-gpio = <&lsio_gpio4 0 GPIO_ACTIVE_LOW>;
> > > vpcie-supply = <&reg_pcieb>;
> > > + vpcie3v3aux-supply = <&reg_pcieb>;
> >
> > Is it a documented binding?
> Yes, it is. Please refer to what's Rob said below.
>
> "
> It is standard because PCIe spec defines them. pci-bus-common.yaml already defines these:
>
> vpcie12v-supply:
> description: 12v regulator phandle for the slot
>
> vpcie3v3-supply:
> description: 3.3v regulator phandle for the slot
>
> vpcie3v3aux-supply:
> description: 3.3v AUX regulator phandle for the slot
>
> Note that these should really be defined in the root port node rather than the host bridge node. We've done the latter because the RP node is often not defined.
>
> Rob
> "

Shawn:

Check https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/pci/pci-bus-common.yaml

Frank

>
> Best Regards
> Richard Zhu
> >
> > Shawn
> >
> > > status = "okay";
> > > };
> > >
> > > --
> > > 2.37.1
> > >
>