Re: [PATCH net-next v10 1/6] dt-bindings: net: pcs: add rockchip,rk3568-xpcs support

On October 6, 2026 9:24:28 PM GMT+08:00, Rob Herring [off-list ref] wrote:

On Tue, Oct 06, 2026 at 06:30:03AM +0800, Coia Prant wrote:

quoted

Add device tree binding documentation for the Synopsys DesignWare
XPCS integrated on the Rockchip RK3568 SoC.

The XPCS is accessed over the APB3 bus and internally connected to
a Naneng Combo SerDes PHY.  It supports 1000BASE-X, SGMII, and
QSGMII modes, with four MII ports.

The four MII ports are described as ethernet-pcs-mii@N child nodes,
consumed by the Rockchip XPCS glue driver later in this series.

phys and phy-names are required because dtbs_check only validates
required properties for enabled nodes. The SerDes link is a board-level
design choice (combphy1 on some boards, combphy2 on others), so these
properties must be provided by the board device tree, not the SoC dtsi.

The CRU reset lines (SRST_XPCS*) are intentionally not described: no
in-tree user requests them, and bring-up relies on the PD_PIPE power
domain, the SerDes PHY and the in-IP soft reset. They can be added
later as optional without breaking ABI.

Signed-off-by: Coia Prant <redacted>
---
 .../net/pcs/rockchip,rk3568-xpcs.yaml         | 110 ++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/pcs/rockchip,rk3568-xpcs.yaml

diff --git a/Documentation/devicetree/bindings/net/pcs/rockchip,rk3568-xpcs.yaml b/Documentation/devicetree/bindings/net/pcs/rockchip,rk3568-xpcs.yaml
new file mode 100644
index 0000000000000..703fcff0e3f70
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/pcs/rockchip,rk3568-xpcs.yaml

@@ -0,0 +1,110 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/pcs/rockchip,rk3568-xpcs.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Rockchip RK3568 Synopsys DesignWare Ethernet PCS
+
+maintainers:
+  - Coia Prant <coiaprant@gmail.com>
+
+description: |
+  Rockchip RK3568 SoC integrates a Synopsys DesignWare Ethernet Physical
+  Coding Sublayer (XPCS).
+  The PCS provides an interface between the Media Access Control (MAC)
+  and the Physical Medium Attachment (PMA) sublayer through a Media
+  Independent Interface (GMII).
+
+  The XPCS is accessed over the APB3 bus and internally connected to a
+  Naneng Combo SerDes PHY.
+  It supports 1000BASE-X, SGMII and QSGMII modes.
+
+  The block contains four MII ports that can be individually enabled and
+  routed to one of the Ethernet GMAC controllers via the pcs-handle
+  property in the MAC device tree node.
+
+properties:
+  compatible:
+    const: rockchip,rk3568-xpcs
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  clocks:
+    items:
+      - description: APB3 bus interface clock (clk_csr_i), required for register access
+      - description: EEE clock (clk_eee_i), required for Energy Efficient Ethernet operation
+
+  clock-names:
+    items:
+      - const: csr
+      - const: eee
+
+  phys:
+    maxItems: 1
+
+  phy-names:
+    const: serdes

You don't really need phy-names if there is only 1 entry.

quoted

+
+  power-domains:
+    maxItems: 1
+
+patternProperties:
+  "^ethernet-pcs-mii@[0-3]$":
+    type: object
+    description:
+      One of the four MII ports of the XPCS. The port is linked to an
+      Ethernet MAC controller via the pcs-handle property in the MAC's
+      device tree node.
+
+    properties:
+      reg:
+        description: MII port number.
+        enum: [0, 1, 2, 3]
+
+    required:
+      - reg

Why the child nodes? They don't contain anything.

Perhaps that's due to pcs-handle not supporting arg cells to pass the 
port number? That's about to change[1].

Rob

[1] https://github.com/devicetree-org/dt-schema/pull/198

Hi Rob,

Both points make sense.

1. I'll drop phy-names since there's only a single entry.

2. For the ethernet-pcs-mii child nodes: you're right that they only
   contain 'reg'. The reason I used child nodes is because pcs-handle
   arg cells are not available yet -- PR #198 is still open and in
   RFC/change-request state.

   The RZN1 MII converter binding does the same thing: it declares
   MII ports as subnodes and references the PCS via pcs-handle, until
   arg cells land.

   So I'd like to keep the child nodes as a temporary workaround, and
   I'll add a note in the binding that this can be simplified once
   PR #198 is merged.

Thanks,
Coia