[openwrt/openwrt] ath79: fix nanobeam ac ethernet interface

[LEDE Commits]

adrian pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/50a76208bcce98977615d8048f7655aa2f49cf38

commit 50a76208bcce98977615d8048f7655aa2f49cf38
Author: Nick Hainke <vincent at systemli.org>
AuthorDate: Sun Oct 25 15:25:01 2020 +0100

    ath79: fix nanobeam ac ethernet interface
    
    In 4.14 the delays were not cleared, so setting "rgmii" as phy-mode
    did not affect delays set by the bootloader. With 5.4 kernel the
    situation changed and the ethernet interface stopped working.
    
    "rgmii" requires rx and tx delays depending on the hardware circuit
    and wiring. The mac or the phy can add these delays.
    - "rgmii":  delays are controlled by the mac
    - "rgmii-id": delays are controlled by the phy
    More Information in Linux Kernel Tree:
    Documentation/devicetree/bindings/net/ethernet-controller.yaml
    
    "rgmii" should be the preferred mode, which allows the mac layer to
    turn off the dealys completely if they are not needed. However, the
    delays are not set correctly, which causes the ethernet interface
    to be broken. Just taking the ethernetpart from the litebeam ac gen2
    will fix the issue.
    
    Explained-by: David Bauer <mail at david-bauer.net>
    Signed-off-by: Nick Hainke <vincent at systemli.org>
---
 target/linux/ath79/dts/ar9342_ubnt_nanobeam-ac.dts | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/target/linux/ath79/dts/ar9342_ubnt_nanobeam-ac.dts b/target/linux/ath79/dts/ar9342_ubnt_nanobeam-ac.dts
index 6f6e4c6bb6..3dd1ba4532 100644
--- a/target/linux/ath79/dts/ar9342_ubnt_nanobeam-ac.dts
+++ b/target/linux/ath79/dts/ar9342_ubnt_nanobeam-ac.dts
@@ -42,7 +42,6 @@
 
 	phy-mask = <4>;
 	phy4: ethernet-phy at 4 {
-		phy-mode = "rgmii";
 		reg = <4>;
 	};
 };
@@ -51,11 +50,11 @@
 	status = "okay";
 
 	/* default for ar934x, except for 1000M and 10M */
-	pll-data = <0x06000000 0x00000101 0x00001313>;
+	pll-data = <0x02000000 0x00000101 0x00001313>;
 
 	mtd-mac-address = <&art 0x0>;
 
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 	phy-handle = <&phy4>;
 
 	gmac-config {