[PATCH v3] arm64: dts: ti: k3-am62p: use eFuse MAC Address for CPSW3G Port 1

[Siddharth Vadapalli]

Add the "ethernet-mac-syscon" node within "wkup_conf" node corresponding to
the CTRLMMR_MAC_IDx registers within the CTRL_MMR space. Assign the
compatible "ti,am62p-cpsw-mac-efuse" to enable "syscon_regmap" operations
on these registers. The MAC Address programmed in the eFuse is accessible
through the CTRLMMR_MAC_IDx registers. The "ti,syscon-efuse" device-tree
property points to the CTRLMMR_MAC_IDx registers, allowing the CPSW driver
to fetch the MAC Address and assign it to the network interface associated
with CPSW3G MAC Port 1.

Signed-off-by: Siddharth Vadapalli <s-vadapalli@xxxxxx>
---

This patch is based on linux-next tagged next-20240404.
Patch depends on:
https://patchwork.kernel.org/project/linux-arm-kernel/patch/20240402105708.4114146-1-s-vadapalli@xxxxxx/
for the newly added "ti,am62p-cpsw-mac-efuse" compatible.

v2:
https://patchwork.kernel.org/project/linux-arm-kernel/patch/20240404081845.622707-1-s-vadapalli@xxxxxx/
Changes since v2:
- Renamed "cpsw-mac-efuse" node as "ethernet-mac-syscon" based on
  Krzysztof's suggestion.
- Renamed "cpsw_mac_efuse" label as "cpsw_mac_syscon" to match
  node naming convention.
- Updated node-name in commit message to "ethernet-mac-syscon".

v1:
https://patchwork.kernel.org/project/linux-arm-kernel/patch/20240402094200.4036076-1-s-vadapalli@xxxxxx/
Changes since v1:
- Since "wkup_conf" is modelled as a "simple-bus" rather than being
  modelled as a System Controller node with the "syscon" compatible,
  directly passing the reference to the "wkup_conf" node using the
  "ti,syscon-efuse" device-tree property will not work.
  Therefore, I posted the patch at:
  https://patchwork.kernel.org/project/linux-arm-kernel/patch/20240402105708.4114146-1-s-vadapalli@xxxxxx/
  in order to add a new compatible to be used for modelling the
  CTRLMMR_MAC_IDx registers as System Controller nodes, thereby
  allowing the existing "ti,syscon-efuse" property to be used.
  Now, "ti,syscon-efuse" points to the "cpsw_mac_efuse" node within
  "wkup_conf" node, with "cpsw_mac_efuse" being a "syscon" node.

Logs verifying that the CPSW driver assigns the MAC Address from the
eFuse based on the CTRLMMR_MAC_IDx registers at 0x43000200 and 0x43000204
to the interface eth0 corresponding to CPSW3G MAC Port 1:
https://gist.github.com/Siddharth-Vadapalli-at-TI/63473d68e7a34860566c1339ce3da9f0

 arch/arm64/boot/dts/ti/k3-am62p-main.dtsi   | 1 +
 arch/arm64/boot/dts/ti/k3-am62p-wakeup.dtsi | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am62p-main.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-main.dtsi
index 7337a9e13535..21020b7d3034 100644
--- a/arch/arm64/boot/dts/ti/k3-am62p-main.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62p-main.dtsi
@@ -696,6 +696,7 @@ cpsw_port1: port@1 {
 				label = "port1";
 				phys = <&phy_gmii_sel 1>;
 				mac-address = [00 00 00 00 00 00];
+				ti,syscon-efuse = <&cpsw_mac_syscon 0x0>;
 			};
 
 			cpsw_port2: port@2 {
diff --git a/arch/arm64/boot/dts/ti/k3-am62p-wakeup.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-wakeup.dtsi
index a84756c336d0..7469b3d3a8c9 100644
--- a/arch/arm64/boot/dts/ti/k3-am62p-wakeup.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62p-wakeup.dtsi
@@ -18,6 +18,11 @@ chipid: chipid@14 {
 			reg = <0x14 0x4>;
 			bootph-all;
 		};
+
+		cpsw_mac_syscon: ethernet-mac-syscon@200 {
+			compatible = "ti,am62p-cpsw-mac-efuse", "syscon";
+			reg = <0x200 0x8>;
+		};
 	};
 
 	wkup_uart0: serial@2b300000 {
-- 
2.40.1