[PATCH v7 6/7] ARM: dts: microchip: sama5d27_wlsom1: read MAC address from QSPI SFDP

Describe the QSPI flash SFDP as an NVMEM provider with the
microchip,sst26vf-sfdp-eui layout, which exposes the factory-programmed
EUI-48 as a "mac-address" cell, and point macb0 at it through
nvmem-cells. This yields a stable MAC address on boards where U-Boot does
not program one, instead of falling back to a random address.

The sama5d27_wlsom1 SoM is fitted with the factory-programmed
SST26VF064BEUI, and the QSPI flash node is only enabled on boards carrying
that part, so the EUI-48 marker and its "mac-address" cell are always
present. Boards without an EUI-programmed part simply do not reference the
cell, so macb0 never defers waiting for it.

Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
---
 arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1.dtsi | 11 +++++++++++
 .../boot/dts/microchip/at91-sama5d27_wlsom1_ek.dts    |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1.dtsi b/arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1.dtsi
index 062aa02a98ed..6016d7f2a39c 100644
--- a/arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1.dtsi
+++ b/arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1.dtsi

@@ -240,6 +240,17 @@ qspi1_flash: flash@0 {
 		m25p,fast-read;
 		status = "disabled";
 
+		sfdp {
+			compatible = "jedec,sfdp";
+
+			nvmem-layout {
+				compatible = "microchip,sst26vf-sfdp-eui";
+
+				mac_address_eui48: mac-address {
+				};
+			};
+		};
+
 		partitions {
 			compatible = "fixed-partitions";
 			#address-cells = <1>;

diff --git a/arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1_ek.dts b/arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1_ek.dts
index 35a933eec573..5e87bf04bc47 100644
--- a/arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1_ek.dts
+++ b/arch/arm/boot/dts/microchip/at91-sama5d27_wlsom1_ek.dts

@@ -97,6 +97,8 @@ uart6: serial@200 {
 
 &macb0 {
 	status = "okay";
+	nvmem-cells = <&mac_address_eui48>;
+	nvmem-cell-names = "mac-address";
 };
 
 &pioA {

-- 
2.43.0