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

From: "Russell King (Oracle)" <[email-masked]>
Date: Thu, 29 Jan 2026 12:50:32 +0000

On Mon, Jan 26, 2026 at 10:21:56AM +0100, Vincent Guittot wrote:
> Describe the serdes subsystem available on the S32G platforms.
> 
> Signed-off-by: Vincent Guittot <[email-masked]>
> ---
>  .../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 <[email-masked]>
> +
> +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.

-- 
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