On 09/03/2026 17:45, Andrew Lunn wrote:

quoted

quoted

+    doc: |
+      Loopback component. Identifies where in the network path the
+      loopback is applied.
+    entries:
+      -
+        name: mac
+        doc: MAC loopback
+      -
+        name: pcs
+        doc: PCS loopback
+      -
+        name: phy
+        doc: PHY loopback
+      -
+        name: module
+        doc: Pluggable module (e.g. CMIS (Q)SFP) loopback

Should we also add "serdes" ?

What is the difference between SERDES and PCS?

By Serdes I mean "generic PHY", but as you state below I don't really
want to use the word "PHY" as it's very prone to confusion with Ethernet
PHYs.

Maybe we should also make it clear PHY means Ethernet PHY. The Marvell
Generic PHYs have

phy-mvebu-a3700-comphy.c:#define COMPHY_DIG_LOOPBACK_EN		0x23
phy-mvebu-cp110-comphy.c:#define MVEBU_COMPHY_LOOPBACK(n)		(0x88c + (n) * 0x1000)

which suggests it can also do loopback. We don't want PHY meaning two
different things.

Agreed,

Maxime