RE: [PATCH v3 1/2] ARM: dts: imx6qp-sabresd: Enable PCIe support

[Hongxing Zhu]

> -----Original Message-----
> From: Shawn Guo <shawnguo@xxxxxxxxxx>
> Sent: 2022年2月21日 12:20
> To: Hongxing Zhu <hongxing.zhu@xxxxxxx>
> Cc: l.stach@xxxxxxxxxxxxxx; bhelgaas@xxxxxxxxxx;
> lorenzo.pieralisi@xxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>
> Subject: Re: [PATCH v3 1/2] ARM: dts: imx6qp-sabresd: Enable PCIe support
> 
> On Tue, Feb 15, 2022 at 01:16:31PM +0800, Richard Zhu wrote:
> > In the i.MX6QP sabresd board(sch-28857) design, one external
> > oscillator is powered up by vgen3 and used as the PCIe reference clock
> > source by the endpoint device.
> >
> > If RC uses this oscillator as reference clock too, PLL6(ENET PLL)
> > would has to be in bypass mode, and ENET clocks would be messed up.
> >
> > To keep things simple, let RC use the internal PLL as reference clock
> > and set vgen3 always on to enable the external oscillator for endpoint
> > device on i.MX6QP sabresd board.
> >
> > NOTE: This reference clock setup is used to pass the GEN2 TX
> > compliance tests, and isn't recommended as a setup in the end-user design.
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > ---
> >  arch/arm/boot/dts/imx6qp-sabresd.dts | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/boot/dts/imx6qp-sabresd.dts
> > b/arch/arm/boot/dts/imx6qp-sabresd.dts
> > index 480e73183f6b..083cf90bcab5 100644
> > --- a/arch/arm/boot/dts/imx6qp-sabresd.dts
> > +++ b/arch/arm/boot/dts/imx6qp-sabresd.dts
> > @@ -50,8 +50,14 @@ MX6QDL_PAD_SD3_DAT7__SD3_DATA7
> 	0x17059
> >  	};
> >  };
> >
> > +&vgen3_reg {
> > +	regulator-min-microvolt = <1800000>;
> > +	regulator-max-microvolt = <3300000>;
> 
> These can be saved, as they are unchanged?

Good caught. Thanks.
These two lines would be removed, since they are not changed.

Best Regards
Richard Zhu

> 
> Shawn
> 
> > +	regulator-always-on;
> > +};
> > +
> >  &pcie {
> > -	status = "disabled";
> > +	status = "okay";
> >  };
> >
> >  &sata {
> > --
> > 2.25.1
> >