From 4cb6316d33d8ccf982f8975b1ea5f7f3f71c8da1 Mon Sep 17 00:00:00 2001 From: Dimitri Fedrau Date: Wed, 16 Apr 2025 19:14:47 +0200 Subject: [PATCH] dt-bindings: net: ethernet-phy: add property mac-termination-ohms Add property mac-termination-ohms in the device tree bindings for selecting the resistance value of the builtin series termination resistors of the PHY. Changing the resistance to an appropriate value can reduce signal reflections and therefore improve signal quality. Signed-off-by: Dimitri Fedrau Reviewed-by: Rob Herring (Arm) Link: https://patch.msgid.link/20250416-dp83822-mac-impedance-v3-1-028ac426cddb@liebherr.com Signed-off-by: Jakub Kicinski --- .../devicetree/bindings/net/ethernet-phy.yaml | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml index 824bbe4333b7..71e2cd32580f 100644 --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml @@ -238,6 +238,16 @@ properties: peak-to-peak specified in ANSI X3.263. When omitted, the PHYs default will be left as is. + mac-termination-ohms: + maximum: 200 + description: + The xMII signals need series termination on the driver side to match both + the output driver impedance and the line characteristic impedance, to + prevent reflections and EMI problems. Select a resistance value which is + supported by the builtin resistors of the PHY, otherwise the resistors may + have to be placed on board. When omitted, the PHYs default will be left as + is. + leds: type: object -- 2.50.1