Re: [PATCH 1/1] riscv: dts: spacemit: enable onboard eeprom for OrangePi

From: Gong Shuai <hidden>
Date: 2026-09-05 17:05:30
Also in: linux-riscv, lkml, spacemit
Subsystem: risc-v architecture, risc-v spacemit soc support, the rest · Maintainers: Paul Walmsley, Palmer Dabbelt, Albert Ou, Yixun Lan, Linus Torvalds

On 9/1/2026 4:00 PM, Chukun Pan wrote:

quoted hunk ↗ jump to hunk

Enable the i2c2 bus and add the connected GT24C02B EEPROM.

[   6.766] TlvInfo Header:
[   6.766]    Id String:    TlvInfo
[   6.769]    Version:      1
[   6.772]    Total Length: 38
[   6.775] TLV Name             Code Len Value
[   6.779] -------------------- ---- --- -----
[   6.783] Base MAC Address     0x24   6 .....
[   6.788] MAC Addresses        0x2A   2 2
[   6.792] Product Name         0x21  15 x1_orangepi-r2s
[   6.797] Unknown              0x41   1  0x01
[   6.801] CRC-32               0xFE   4 0xE5A74B18
[   6.806] Checksum is valid.

Signed-off-by: Chukun Pan <redacted>
---
This patch depends on the following to avoid conflicts:
https://lore.kernel.org/lkml/20260802100101.327815-1-amadeus@jmu.edu.cn/ (local)
---
  .../boot/dts/spacemit/k1-orangepi-r2s.dts     | 30 ++++++++++++++++++
  .../boot/dts/spacemit/k1-orangepi-rv2.dts     | 31 +++++++++++++++++++
  2 files changed, 61 insertions(+)

diff --git a/arch/riscv/boot/dts/spacemit/k1-orangepi-r2s.dts b/arch/riscv/boot/dts/spacemit/k1-orangepi-r2s.dts
index 2d1ba34cb00e..7125f2882ce8 100644
--- a/arch/riscv/boot/dts/spacemit/k1-orangepi-r2s.dts
+++ b/arch/riscv/boot/dts/spacemit/k1-orangepi-r2s.dts

@@ -13,6 +13,7 @@ / {
  	compatible = "xunlong,orangepi-r2s", "spacemit,k1";
  
  	aliases {
+		i2c2 = &i2c2;
  		i2c8 = &i2c8;
  		serial0 = &uart0;
  		ethernet0 = &eth0;

@@ -112,6 +113,35 @@ rgmii1: phy@1 {
  	};
  };
  
+&i2c2 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&i2c2_0_cfg>;
+	status = "okay";
+
+	eeprom@50 {
+		compatible = "atmel,24c02";
+		reg = <0x50>;
+		pagesize = <16>;
+		size = <256>;
+		read-only;
+		vcc-supply = <&buck3_1v8>;
+
+		nvmem-layout {
+			compatible = "onie,tlv-layout";
+
+			mac-address {
+				#nvmem-cell-cells = <1>;
+			};
+
+			num-macs {
+			};
+
+			product-name {
+			};
+		};
+	};
+};
+
  &i2c8 {
  	pinctrl-names = "default";
  	pinctrl-0 = <&i2c8_cfg>;

diff --git a/arch/riscv/boot/dts/spacemit/k1-orangepi-rv2.dts b/arch/riscv/boot/dts/spacemit/k1-orangepi-rv2.dts
index f7547a4da71a..837616255464 100644
--- a/arch/riscv/boot/dts/spacemit/k1-orangepi-rv2.dts
+++ b/arch/riscv/boot/dts/spacemit/k1-orangepi-rv2.dts

@@ -17,6 +17,8 @@ aliases {
  		serial0 = &uart0;
  		ethernet0 = &eth0;
  		ethernet1 = &eth1;
+		i2c2 = &i2c2;
+		i2c8 = &i2c8;
  		mmc0 = &emmc;
  		mmc1 = &sdhci0;
  	};

@@ -138,6 +140,35 @@ rgmii1: phy@1 {
  	};
  };
  
+&i2c2 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&i2c2_0_cfg>;
+	status = "okay";
+
+	eeprom@50 {
+		compatible = "atmel,24c02";
+		reg = <0x50>;
+		pagesize = <16>;
+		size = <256>;
+		read-only;
+		vcc-supply = <&buck3_1v8>;
+
+		nvmem-layout {
+			compatible = "onie,tlv-layout";
+
+			mac-address {
+				#nvmem-cell-cells = <1>;
+			};
+
+			num-macs {
+			};
+
+			product-name {
+			};
+		};
+	};
+};
+
  &i2c8 {
  	pinctrl-names = "default";
  	pinctrl-0 = <&i2c8_cfg>;


Hi Chukun,

I have tested this patch on an OrangePi RV2 with a kernel built from
linux-next (next-20260904).

With the patch applied, the i2c2 bus comes up and a 24C02-compatible
EEPROM (256 bytes) is probed at 2-0050. Reading the raw contents via

     hexdump -C /sys/bus/nvmem/devices/2-00500/nvmem

shows a valid ONIE TlvInfo table, and the nvmem cells
(product-name, mac-address, num-macs, crc32) are properly exposed.
The Product Name field reads "x1_orangepi-rv2", which matches this
board.

Tested-by: Gong Shuai <redacted> # OrangePi-RV2


I also tested the MAC address wiring below on top of this patch, with
the nvmem-cells references added to eth0/eth1, eth0 picks up the base
MAC address stored in the EEPROM and eth1 gets the base + 1; both
addresses stay stable across reboots.

diff --git a/arch/riscv/boot/dts/spacemit/k1-orangepi-rv2.dts b/arch/riscv/boot/dts/spacemit/k1-orangepi-rv2.dts
index 837616255464..44b81268c802 100644
--- a/arch/riscv/boot/dts/spacemit/k1-orangepi-rv2.dts
+++ b/arch/riscv/boot/dts/spacemit/k1-orangepi-rv2.dts

@@ -93,6 +93,8 @@ &emmc {

};

&eth0 {
+   nvmem-cells = <&mac_address 0>;
+   nvmem-cell-names = "mac-address";
  phy-handle = <&rgmii0>;
  phy-mode = "rgmii-id";
  pinctrl-names = "default";

@@ -117,6 +119,8 @@ rgmii0: phy@1 {

};

&eth1 {
+   nvmem-cells = <&mac_address 1>;
+   nvmem-cell-names = "mac-address";
  phy-handle = <&rgmii1>;
  phy-mode = "rgmii-id";
  pinctrl-names = "default";

@@ -156,7 +160,7 @@ eeprom@50 {

	nvmem-layout {
	   compatible = "onie,tlv-layout";

-         mac-address {
+         mac_address: mac-address {
		  #nvmem-cell-cells = <1>;
	   };


But I am not sure whether this wiring should be part of this patch.
Without such wiring, the kernel falls back to random MAC addresses
on this board.

Best regards,
Shuai

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