[net-next PATCH v2 07/14] net: dsa: ocelot: suppress PHY device scanning on the internal MDIO bus

Sean Anderson
2025-04-07T23:18:16Z

From: Vladimir Oltean <vladimir.oltean@nxp.com>

This bus contains Lynx PCS devices, and if the lynx-pcs driver ever
decided to call mdio_device_register(), it would fail due to
mdiobus_scan() having created a dummy phydev for the same address
(the PCS responds to standard clause 22 PHY ID registers and can
therefore by autodetected by phylib which thinks it's a PHY).

On the Seville driver, things are a bit more complicated, since bus
creation is handled by mscc_miim_setup() and that is shared with the
dedicated mscc-miim driver. Suppress PHY scanning only for the Seville
internal MDIO bus rather than for the whole mscc-miim driver, since we
know that on NXP T1040, this bus only contains Lynx PCS devices.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
---

(no changes since v1)

drivers/net/dsa/ocelot/felix_vsc9959.c | 4 ++++
drivers/net/dsa/ocelot/seville_vsc9953.c | 5 +++++
2 files changed, 9 insertions(+)

diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index 940f1b71226d..2de12611ab57 100644
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/drivers/net/dsa/ocelot/felix_vsc9959.c
@@ -1001,6 +1001,10 @@ static int vsc9959_mdio_bus_alloc(struct ocelot *ocelot)
bus->read_c45 = enetc_mdio_read_c45;
bus->write_c45 = enetc_mdio_write_c45;
bus->parent = dev;
+ /* Suppress PHY device creation in mdiobus_scan(),
+ * we have Lynx PCSs
+ */
+ bus->phy_mask = ~0;
mdio_priv = bus->priv;
mdio_priv->hw = hw;
/* This gets added to imdio_regs, which already maps addresses
diff --git a/drivers/net/dsa/ocelot/seville_vsc9953.c b/drivers/net/dsa/ocelot/seville_vsc9953.c
index eb3944ba2a72..28bcdef34a6c 100644
--- a/drivers/net/dsa/ocelot/seville_vsc9953.c
+++ b/drivers/net/dsa/ocelot/seville_vsc9953.c
@@ -901,6 +901,11 @@ static int vsc9953_mdio_bus_alloc(struct ocelot *ocelot)
return rc;
}

+ /* Suppress PHY device creation in mdiobus_scan(),
+ * we have Lynx PCSs
+ */
+ bus->phy_mask = ~0;
+
/* Needed in order to initialize the bus mutex lock */
rc = devm_of_mdiobus_register(dev, bus, NULL);
if (rc < 0) {
--
2.35.1.1320.gc452695387.dirty