[PATCH] powerpc: dts: turris1x.dts: Describe switch PHYs on the MDIO bus

[Josef Schlehofer <pepe.schlehofer@gmail.com>]

The QCA8337's integrated PHYs are visible on the same MDIO bus as the
KSZ9031, at addresses 0–4. Since they are not described in the device
tree, qca8k accesses them through the switch's MDIO master.

Describe the PHYs and reference them from the switch ports so phylib
accesses them directly through the MDIO bus. This fixes intermittent
WAN link recovery failures on Turris 1.x.

Tested on Turris 1.1: 40 WAN link down/up cycles across 3 boots and
10 LAN link down/up cycles passed.

Fixes: 54c15ec3b738 ("powerpc: dts: Add DTS file for CZ.NIC Turris 1.x routers")
Cc: stable@vger.kernel.org
Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>
---
Tested with OpenWrt's 6.18.44 kernel.

Andrew asked in [1] whether the internal PHYs show up on the host MDIO
bus: they do, at mdio@ffe24520:00..04. The same workaround was found
for a QCA8327 board in [2].

[1] https://lore.kernel.org/netdev/20250425151309.30493-1-kabel@kernel.org/
[2] https://lore.kernel.org/all/ao8DqOFZJkln4pvh@larwa.hq.kempniu.pl/

 arch/powerpc/boot/dts/turris1x.dts | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/powerpc/boot/dts/turris1x.dts b/arch/powerpc/boot/dts/turris1x.dts
index dff1ea074d9d..977f9f9c63c7 100644
--- a/arch/powerpc/boot/dts/turris1x.dts
+++ b/arch/powerpc/boot/dts/turris1x.dts
@@ -143,6 +143,27 @@ fixed-link {
 		};
 
 		mdio@24520 {
+			/* Integrated PHYs of QCA8337N-AL3C switch ports 1-5 */
+			phy_port1: ethernet-phy@0 {
+				reg = <0x0>;
+			};
+
+			phy_port2: ethernet-phy@1 {
+				reg = <0x1>;
+			};
+
+			phy_port3: ethernet-phy@2 {
+				reg = <0x2>;
+			};
+
+			phy_port4: ethernet-phy@3 {
+				reg = <0x3>;
+			};
+
+			phy_port5: ethernet-phy@4 {
+				reg = <0x4>;
+			};
+
 			/* KSZ9031RNXCA ethernet phy for WAN port */
 			phy: ethernet-phy@7 {
 				interrupts = <3 1 0 0>;
@@ -174,26 +195,31 @@ fixed-link {
 					port@1 {
 						reg = <1>;
 						label = "lan5";
+						phy-handle = <&phy_port1>;
 					};
 
 					port@2 {
 						reg = <2>;
 						label = "lan4";
+						phy-handle = <&phy_port2>;
 					};
 
 					port@3 {
 						reg = <3>;
 						label = "lan3";
+						phy-handle = <&phy_port3>;
 					};
 
 					port@4 {
 						reg = <4>;
 						label = "lan2";
+						phy-handle = <&phy_port4>;
 					};
 
 					port@5 {
 						reg = <5>;
 						label = "lan1";
+						phy-handle = <&phy_port5>;
 					};
 
 					port@6 {
-- 
2.54.0 (Apple Git-157)