Thread (28 messages) 28 messages, 5 authors, 2026-01-30

Re: [PATCH 1/4] dt-bindings: serdes: s32g: Add NXP serdes subsystem

From: "Russell King (Oracle)" <linux@armlinux.org.uk>
Date: 2026-01-29 12:50:42
Also in: linux-arm-kernel, linux-devicetree, linux-phy, lkml

On Mon, Jan 26, 2026 at 10:21:56AM +0100, Vincent Guittot wrote:
quoted hunk ↗ jump to hunk
Describe the serdes subsystem available on the S32G platforms.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
 .../bindings/phy/nxp,s32g-serdes.yaml         | 154 ++++++++++++++++++
 1 file changed, 154 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/nxp,s32g-serdes.yaml
diff --git a/Documentation/devicetree/bindings/phy/nxp,s32g-serdes.yaml b/Documentation/devicetree/bindings/phy/nxp,s32g-serdes.yaml
new file mode 100644
index 000000000000..fad34bee2a4f
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/nxp,s32g-serdes.yaml
@@ -0,0 +1,154 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/nxp,s32g-serdes.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP S32G2xxx/S32G3xxx SerDes PHY subsystem
+
+maintainers:
+  - Ghennadi Procopciuc <ghennadi.procopciuc@nxp.com>
+
+description: |
+  The SerDes subsystem on S32G SoC Family includes two types of PHYs:
+    - One PCIe PHY: Supports various PCIe operation modes
+    - Two Ethernet Physical Coding Sublayer (XPCS) controllers
+
+  SerDes operation mode selects the enabled PHYs and speeds. Clock frequency
+  must be adapted accordingly. Below table describes all possible operation
+  modes.
+
+  Mode  PCIe	XPCS0		XPCS1		PHY clock	Description
+                SGMII		SGMII		  (MHz)
+  -------------------------------------------------------------------------
+  0	Gen3	N/A		N/A		100		Single PCIe
+  1	Gen2	1.25Gbps	N/A		100		PCIe/SGMII
+  2	Gen2	N/A		1.25Gbps	100		PCIe/SGMII
+  3	N/A	1.25Gbps	1.25Gbps	100,125		SGMII
+  4	N/A	3.125/1.25Gbps	3.125/1.25Gbps 	125		SGMII
+  5	Gen2	N/A	        3.125Gbps     	100		PCIe/SGMII
Shouldn't the mode be configured via phy_set_mode_ext()?

This identifies whether it is operating as PCIe or for networking and
in the case of networking, the PHY interface mode should be passed as
the submode.

Have a look at include/linux/phy/pcie.h to see the submodes that may
be appropriate to pass to phy_set_mode_ext() - but talk to the PHY
subsystem maintainers.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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