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

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@kernel.org>
Sent: Friday, May 7, 2021 5:01 AM
To: Lucas Stach <l.stach@pengutronix.de>
Cc: lorenzo.pieralisi@arm.com; linux-pci@vger.kernel.org; dl-linux-imx
[off-list ref]; linux-arm-kernel@lists.infradead.org;
linux-kernel@vger.kernel.org; kernel@pengutronix.de; Richard Zhu
[off-list ref]; andrew.smirnov@gmail.com;
shawnguo@kernel.org; kw@linux.com; bhelgaas@google.com;
stefan@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:

quoted

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.

quoted

Am Dienstag, dem 30.03.2021 um 16:08 +0800 schrieb Richard Zhu:

quoted

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.

quoted

quoted

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Lucas Stach <l.stach@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

quoted

quoted

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

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