This describes the two on-board Realtek RTL8125BG PCIe Ethernet
controllers on the FriendlyElec NanoPC-T6 (RK3588) board and aliases
them to ethernet0/ethernet1.

Many Rockchip boards have on-board RTL8125 PCIe NICs, wired to
pcie2x1l0 and pcie2x1l2. The controllers were already enabled in the
board DT, but the Ethernet function nodes themselves are not
described, so the kernel (and u-boot) has no DT handle on the NICs.

Adding the function nodes lets us:
- expose stable ethernet0/ethernet1 aliases for the two NICs, the
  same way other rk3588 boards alias their GMAC interfaces; and
- let U-Boot's fdt_fixup_ethernet() patch mac-address properties in
  at boot time from its ethaddr/eth1addr environment - useful on
  boards (like this one) whose on-NIC EEPROM is not pre-programmed
  with a unique MAC. The kernel and U-Boot then agree on the MAC,
  which matters for network-boot setups.

Checkpatch warnings:
-  WARNING: DT compatible string "pci10ec,8125" appears un-documented
-  WARNING: DT compatible string vendor "pci10ec" appears un-documented
Both are expected. "pciVVVV,DDDD" is the Open Firmware PCI Bus
Binding spelling, where VVVV/DDDD are the PCI vendor and device IDs
allocated by the PCI-SIG (10ec = Realtek, 8125 = RTL8125). It is not a
DT vendor prefix.

If this is seen as a good thing, it would apply very similarly to
the Radxa Rock 5 series and others.

While at it, rename regulator vcc3v3_pcie2x1l0 to l1, since that is
what is actually powers; since only cosmetic, I did not include
a Fixes tag.

---
Changes in v2:
- fix: pcie2x1l0, not pcie2x1l1; indirectly caught by Sashiko's review [1]
- while-at-it: rename regulator vcc3v3_pcie2x1l0 to l1
- Link to v1: https://patch.msgid.link/20260525-rk3588-dts-rtl-eth-describe-dt-alias-v1-1-a6fcda563ac7@pardini.net

[1] https://sashiko.dev/#/patchset/20260525-rk3588-dts-rtl-eth-describe-dt-alias-v1-1-a6fcda563ac7%40pardini.net

To: Rob Herring <robh@kernel.org>
To: Krzysztof Kozlowski <krzk+dt@kernel.org>
To: Conor Dooley <conor+dt@kernel.org>
To: Heiko Stuebner <heiko@sntech.de>
Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: devicetree@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ricardo Pardini <ricardo@pardini.net>

---
Ricardo Pardini (2):
      arm64: dts: rockchip: describe PCIe Ethernet controllers on NanoPC-T6
      arm64: dts: rockchip: fix PCIe regulator name on NanoPC-T6

 arch/arm64/boot/dts/rockchip/rk3588-nanopc-t6.dtsi | 36 ++++++++++++++++++++--
 1 file changed, 33 insertions(+), 3 deletions(-)
---
base-commit: e7ae89a0c97ce2b68b0983cd01eda67cf373517d
change-id: 20260524-rk3588-dts-rtl-eth-describe-dt-alias-c1ed187b7c50

Best regards,
--  
Ricardo Pardini <ricardo@pardini.net>

Hi,

On Fri, May 29, 2026 at 05:31:23PM +0200, Ricardo Pardini via B4 Relay wrote:
> This describes the two on-board Realtek RTL8125BG PCIe Ethernet
> controllers on the FriendlyElec NanoPC-T6 (RK3588) board and aliases
> them to ethernet0/ethernet1.
> 
> Many Rockchip boards have on-board RTL8125 PCIe NICs, wired to
> pcie2x1l0 and pcie2x1l2. The controllers were already enabled in the
> board DT, but the Ethernet function nodes themselves are not
> described, so the kernel (and u-boot) has no DT handle on the NICs.
> 
> Adding the function nodes lets us:
> - expose stable ethernet0/ethernet1 aliases for the two NICs, the
>   same way other rk3588 boards alias their GMAC interfaces; and
> - let U-Boot's fdt_fixup_ethernet() patch mac-address properties in
>   at boot time from its ethaddr/eth1addr environment - useful on
>   boards (like this one) whose on-NIC EEPROM is not pre-programmed
>   with a unique MAC. The kernel and U-Boot then agree on the MAC,
>   which matters for network-boot setups.

This is the patch rationale and thus should be part of the commit
message in the first patch.

> Checkpatch warnings:
> -  WARNING: DT compatible string "pci10ec,8125" appears un-documented
> -  WARNING: DT compatible string vendor "pci10ec" appears un-documented
> Both are expected. "pciVVVV,DDDD" is the Open Firmware PCI Bus
> Binding spelling, where VVVV/DDDD are the PCI vendor and device IDs
> allocated by the PCI-SIG (10ec = Realtek, 8125 = RTL8125). It is not a
> DT vendor prefix.

No, it is not expected. We need some binding for it :) This is
similar to USB, see e.g.

Documentation/devicetree/bindings/net/microchip,lan95xx.yaml

Greetings,

-- Sebastian

> If this is seen as a good thing, it would apply very similarly to
> the Radxa Rock 5 series and others.
> 
> While at it, rename regulator vcc3v3_pcie2x1l0 to l1, since that is
> what is actually powers; since only cosmetic, I did not include
> a Fixes tag.
> 
> ---
> Changes in v2:
> - fix: pcie2x1l0, not pcie2x1l1; indirectly caught by Sashiko's review [1]
> - while-at-it: rename regulator vcc3v3_pcie2x1l0 to l1
> - Link to v1: https://patch.msgid.link/20260525-rk3588-dts-rtl-eth-describe-dt-alias-v1-1-a6fcda563ac7@pardini.net
> 
> [1] https://sashiko.dev/#/patchset/20260525-rk3588-dts-rtl-eth-describe-dt-alias-v1-1-a6fcda563ac7%40pardini.net
> 
> To: Rob Herring <robh@kernel.org>
> To: Krzysztof Kozlowski <krzk+dt@kernel.org>
> To: Conor Dooley <conor+dt@kernel.org>
> To: Heiko Stuebner <heiko@sntech.de>
> Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
> Cc: devicetree@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-rockchip@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Ricardo Pardini <ricardo@pardini.net>
> 
> ---
> Ricardo Pardini (2):
>       arm64: dts: rockchip: describe PCIe Ethernet controllers on NanoPC-T6
>       arm64: dts: rockchip: fix PCIe regulator name on NanoPC-T6
> 
>  arch/arm64/boot/dts/rockchip/rk3588-nanopc-t6.dtsi | 36 ++++++++++++++++++++--
>  1 file changed, 33 insertions(+), 3 deletions(-)
> ---
> base-commit: e7ae89a0c97ce2b68b0983cd01eda67cf373517d
> change-id: 20260524-rk3588-dts-rtl-eth-describe-dt-alias-c1ed187b7c50
> 
> Best regards,
> --  
> Ricardo Pardini <ricardo@pardini.net>
> 
>