[EXT] Re: [RESEND v4 1/2] dt-bindings: imx6q-pcie: add one regulator used to power up pcie phy

[Richard Zhu]

Hi Bjorn:
It seems that the email I replied on May07, is missing.
Re-send it again.

Best Regards
Richard Zhu

> -----Original Message-----
> From: Bjorn Helgaas <helgaas at kernel.org>
> Sent: Friday, May 7, 2021 5:01 AM
> To: Lucas Stach <l.stach at pengutronix.de>
> Cc: lorenzo.pieralisi at arm.com; linux-pci at vger.kernel.org; dl-linux-imx
> <linux-imx at nxp.com>; linux-arm-kernel at lists.infradead.org;
> linux-kernel at vger.kernel.org; kernel at pengutronix.de; Richard Zhu
> <hongxing.zhu at nxp.com>; andrew.smirnov at gmail.com;
> shawnguo at kernel.org; kw at linux.com; bhelgaas at google.com;
> stefan at agner.ch
> Subject: [EXT] Re: [RESEND v4 1/2] dt-bindings: imx6q-pcie: add one
> regulator used to power up pcie phy
> On Thu, May 06, 2021 at 06:08:24PM +0200, Lucas Stach wrote:
> > Hi Lorenzo,
> >
> > have those two patches fallen through some crack? AFAICS they are gone
> > from patchwork, but I also can't find them in any branch in the usual
> > git repos.
> 
> They were marked "accepted" in patchwork but must have fallen through the
> cracks.  I reset them to "new" and assigned to Lorenzo.
> 
> Neither one follows the subject line capitalization conventions.
> 
> The subject line of this patch (1/2) doesn't really make sense.  I
> *think* this adds a property ("vph-supply") to indicate which regulator supplys
> power to the PHY.
> 
> > Am Dienstag, dem 30.03.2021 um 16:08 +0800 schrieb Richard Zhu:
> > > Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
> > > In default, the PCIE_VPH voltage is suggested to be 1.8v refer to
> > > data sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic
> > > design, the VREG_BYPASS bits of GPR registers should be cleared from
> > > default value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator
> > > would be turned on.
> 
> This commit log doesn't describe the patch, either.  Maybe something like
> this:
> 
>   dt-bindings: imx6q-pcie: Add "vph-supply" for PHY supply voltage
> 
>   The i.MX8MQ PCIe PHY can use either a 1.8V or a 3.3V power supply.
>   Add a "vph-supply" property to indicate which regulator supplies
>   power for the PHY.
> 
[Richard Zhu] I'm fine with this one.

> > > Signed-off-by: Richard Zhu <hongxing.zhu at nxp.com>
> > > Reviewed-by: Lucas Stach <l.stach at pengutronix.de>
> > > ---
> > >  Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git
> > > a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > > b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > > index de4b2baf91e8..d8971ab99274 100644
> > > --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > > +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
> > > @@ -38,6 +38,9 @@ Optional properties:
> > >    The regulator will be enabled when initializing the PCIe host and
> > >    disabled either as part of the init process or when shutting down the
> > >    host.
> > > +- vph-supply: Should specify the regulator in charge of VPH one of
> > > +the three
> > > +  PCIe PHY powers. This regulator can be supplied by both 1.8v and
> > > +3.3v voltage
> > > +  supplies.
> 
> Just going by examples for other drivers, I think this should say something like
> this:
> 
>   - vph-supply: Regulator for i.MX8MQ PCIe PHY.  May supply either
>     1.8V or 3.3V.
> 
> You mentioned "one of the three PCIe PHY powers"; I don't know what that
> means, so I don't know whether it's important to include.
> 
> I also don't know what "vph" means; if the "ph" is part of "phy", it'd be nicer
> to include the "y", so it would be "vphy-supply".
> 
[Richard Zhu] There are three power supplies in total required by the PHY.
- vp: PHY analog and digital supply
- vptxN: PHY transmit supply
-vph: High-voltage power supply.
Only vph is handled by SW here.

BR
Richard
> > >  Additional required properties for imx6sx-pcie:
> > >  - clock names: Must include the following additional entries: