Re: [PATCH 3/5] ARM64: dts: meson-gxbb-p20x: add reset for the ethernet PHY

[Martin Blumenstingl <martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>]

On Wed, Jan 18, 2017 at 11:36 AM, Jerome Brunet <jbrunet-rdvid1DuHRBWk0Htik3J/w@public.gmane.org> wrote:
> On Tue, 2017-01-17 at 22:26 +0100, Martin Blumenstingl wrote:
>> On Tue, Jan 17, 2017 at 8:22 PM, Jerome Brunet <jbrunet-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
>> wrote:
>> >
>> > On Sat, 2016-12-03 at 00:47 +0100, Martin Blumenstingl wrote:
>> > >
>> > > This resets the ethernet PHY during boot to get the PHY into a
>> > > "clean"
>> > > state. While here also specify the phy-handle of the ethmac node
>> > > to
>> > > make the PHY configuration similar to the one we have on GXL
>> > > devices.
>> > >
>> > > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemai
>> > > l.co
>> > > m>
>> > > Tested-by: Neil Armstrong <narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
>> > > ---
>> > >  arch/arm64/boot/dts/amlogic/meson-gxbb-p20x.dtsi | 15
>> > > +++++++++++++++
>> > >  1 file changed, 15 insertions(+)
>> > >
>> > > diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb-p20x.dtsi
>> > > b/arch/arm64/boot/dts/amlogic/meson-gxbb-p20x.dtsi
>> > > index 203be28..2abc553 100644
>> > > --- a/arch/arm64/boot/dts/amlogic/meson-gxbb-p20x.dtsi
>> > > +++ b/arch/arm64/boot/dts/amlogic/meson-gxbb-p20x.dtsi
>> > > @@ -134,10 +134,25 @@
>> > >       pinctrl-names = "default";
>> > >  };
>> > >
>> > > +&mdio0 {
>> > > +     ethernet_phy0: ethernet-phy@0 {
>> > > +             compatible = "ethernet-phy-ieee802.3-c22";
>> > > +             reg = <0>;
>> >
>> > Sorry for the late reply.
>> > I just tried on the p200 and this patch (serie) breaks the network
>> > on
>> > it. The PHY is not detected anymore.
>> >
>> > From the KSZ9031 Datasheet : "PHY Address 0h is supported as the
>> > unique
>> > PHY address only; it is not supported as the broadcast PHY address
>> > [...]"
>> >
>> > So we can't just use the broadcast address here:
>> > reg should be <3>.
>> OK, I'll fix that in a follow-up. as mentioned in the other thread:
>> can you confirm that the PHY ID is 0x00221620?
>
> That's right.
thanks for confirming this

>> It seems that I also broke meson-gxbb-nexbox-a95x.dts with that
>> series
>> (no idea why that slipped through): according to the photos from
>> Neil's wiki [0] this seems to use an IC+ 10/100 ethernet PHY
>> (probably
>> an IP101A)
>
> IP101GR from what I can see on the board.
thanks :)

>>
>> >
>> > >
>> > > +     };
>> > > +};
>> > > +
>> > >  &ethmac {
>> > >       status = "okay";
>> > >       pinctrl-0 = <&eth_rgmii_pins>;
>> > >       pinctrl-names = "default";
>> > > +
>> > > +     phy-handle = <&ethernet_phy0>;
>> > > +
>> > > +     snps,reset-gpio = <&gpio GPIOZ_14 0>;
>> > > +     snps,reset-delays-us = <0 10000 1000000>;
>> > > +     snps,reset-active-low;
>> > > +
>> > > +     phy-mode = "rgmii";
>> >
>> > We can't define this in p20x. actually the p201 uses an rmii.
>> > I have not idea about gpio reset, or the phy address for the p201.
>> >
>> > I suppose it would be better to move this to meson-gxbb_p200.dts
>> >
>> > I don't know if anybody has a p201, but until we can confirm a
>> > working
>> > Ethernet configuration, we should probably drop it for the p201
>> >
>> > Of course the problem was already there before this patch ...
>> indeed, that seems to be a problem.
>> the GXBB Nexbox A95x I mentioned above is based on the p201 board.
>> Amlogic's .dts also toggles GPIOZ_14 for it: [1]
>> chances are high that it also features an IP101A PHY (this is pure
>> speculation though).
>
> Agreed, chances are high it'll be this way.
>
>>
>> I propose four patches to fix all this situation:
>> - add the GPIOZ_14 reset and an ethernet_phy0 (with reg = <0>) to
>> meson-gxbb-nexbox-a95x.dts
>> - add the ethernet_phy0 node with reg = <0> (and ideally I also want
>> to include the KSZ9031 PHY ID) to meson-gxbb-p200.dtsi along with
>> phy-mode = "rgmii"
>
> you mean with reg = <3> ?
you're right, another typo there!

>> - add the ethernet_phy0 node with reg = <0> (without any PHY ID as we
>> don't know which one is used) to meson-gxbb-p201.dtsi along with
>> phy-mode = "rgmii"
>> - remove "phy-mode" and ethernet_phy0 from meson-gxbb-p20x.dtsi and
>> add a comment that both, the RGMII and the RMII PHY have GPIOZ_14
>> connected to their reset line
>
> I'm not too sure about these last 2 points. As you mentioned, we are
> only speculating regarding the p201. I would prefer to avoid putting
> things we are not sure about in the DT (as much as possible).
>
> We could disable the ethernet for p201:
> 1) if nobody complains, situation remains unchanged, ethernet is not
> working on that board
> 2) if someone complains, then we will be able to some facts from
> him/her, and get it working properly.
>
> After all, that's not a regression. With what we had in the meson-gxbb-
> p20x.dtsi so far, ethernet never worked on that board.
fine for me as well
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