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

On Tue, 2017-01-17 at 22:26 +0100, Martin Blumenstingl wrote:

On Tue, Jan 17, 2017 at 8:22 PM, Jerome Brunet [off-list ref]
wrote:

quoted

On Sat, 2016-12-03 at 00:47 +0100, Martin Blumenstingl wrote:

quoted

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 <redacted>
---
?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 at 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.

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.

quoted

quoted

+?????};
+};
+
?&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> ?

- 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.
?

does that make sense?


Regards,
Martin


[0] https://github.com/superna9999/linux/wiki/Boards#nexbox-a95x-s905
[1] https://github.com/khadas/linux/blob/Vim/arch/arm64/boot/dts/amlo
gic/gxbb_p201.dts#L186