[PATCH v2] mx6cuboxi: Fix Ethernet after DT sync with Linux

[Fabio Estevam <festevam@gmail.com>]

From: Josua Mayer <josua@solid-run.com>

The i.MX6 Cubox-i and HummingBoards can have different PHYs at varying
addresses. U-Boot needs to auto-detect which phy is actually present,
and at which address it is responding.

Auto-detection from multiple phy nodes specified in device-tree does not
currently work correct. As a work-around merge all three possible phys
into one node with the special address 0xffffffff which indicates to the
generic phy driver to probe all addresses.

Signed-off-by: Josua Mayer <josua@solid-run.com>
[fabio: Added the changes to imx6qdl-sr-som-u-boot.dtsi.]
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Tested-by: Christian Gmeiner <cgmeiner@igalia.com>
---
Changes since v1:
- Disable ethernet-phy at addresses 0, 1 and 4.
- Remove the fixup of the fake 0xffffff address before booting Linux.

Josua and Christian,

I got access to a imx6 humming board and I was able to test it.

This is the minimal fix I came up based on your suggestions.

There is no need to fixup of the fake 0xffffff address before booting Linux,
as this fake address does not exist in Linux.

Successfully tested Ethernet in U-Boot and in the kernel.

Given that Ethernet is currently broken, I suggest we go with this
version to restore Ethernet for 2024.04.

What do you think?

 ...qdl-hummingboard2-emmc-som-v15-u-boot.dtsi |  1 +
 arch/arm/dts/imx6qdl-sr-som-u-boot.dtsi       | 49 +++++++++++++++++++
 2 files changed, 50 insertions(+)
 create mode 100644 arch/arm/dts/imx6qdl-sr-som-u-boot.dtsi

diff --git a/arch/arm/dts/imx6qdl-hummingboard2-emmc-som-v15-u-boot.dtsi b/arch/arm/dts/imx6qdl-hummingboard2-emmc-som-v15-u-boot.dtsi
index e9b188ed6587..358cf8abc4ff 100644
--- a/arch/arm/dts/imx6qdl-hummingboard2-emmc-som-v15-u-boot.dtsi
+++ b/arch/arm/dts/imx6qdl-hummingboard2-emmc-som-v15-u-boot.dtsi
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 
 #include "imx6qdl-u-boot.dtsi"
+#include "imx6qdl-sr-som-u-boot.dtsi"
 
 / {
 	board-detect {
diff --git a/arch/arm/dts/imx6qdl-sr-som-u-boot.dtsi b/arch/arm/dts/imx6qdl-sr-som-u-boot.dtsi
new file mode 100644
index 000000000000..0bd7df02dd66
--- /dev/null
+++ b/arch/arm/dts/imx6qdl-sr-som-u-boot.dtsi
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+
+#include <dt-bindings/gpio/gpio.h>
+
+&fec {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_microsom_enet_ar8035>;
+	phy-handle = <&phy>;
+	phy-mode = "rgmii-id";
+
+	/*
+	 * The PHY seems to require a long-enough reset duration to avoid
+	 * some rare issues where the PHY gets stuck in an inconsistent and
+	 * non-functional state at boot-up. 10ms proved to be fine .
+	 */
+	phy-reset-duration = <10>;
+	phy-reset-gpios = <&gpio4 15 GPIO_ACTIVE_LOW>;
+	status = "okay";
+
+	mdio {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		ethernet-phy@0 {
+			status = "disabled";
+		};
+
+		ethernet-phy@1 {
+			status = "disabled";
+		};
+
+		ethernet-phy@4 {
+			status = "disabled";
+		};
+
+		phy: ethernet-phy@ffffffff {
+			/*
+			 * The PHY can appear either:
+			 * - AR8035: at address 0 or 4
+			 * - ADIN1300: at address 1
+			 * Actual address being detected at runtime.
+			 */
+			reg = <0xffffffff>;
+			qca,clk-out-frequency = <125000000>;
+			qca,smarteee-tw-us-1g = <24>;
+			adi,phy-output-clock = "125mhz-free-running";
+		};
+	};
+};
-- 
2.34.1