[PATCH net v13 1/4] net: usb: lan78xx: register the PHY interrupt with the MDIO bus

From: Aleksei Sviridkin

Date: Thu Oct 01 2026 - 09:18:57 EST


The interrupt this driver maps for its PHY is written only into
phydev->irq, while the bus table mdiobus->irq[] keeps reading PHY_POLL
for the same address. That table is where phylib records what the bus
described - phy_device_create() seeds phydev->irq from it - so the
number lives only as long as nothing else writes that one field.

Copy the number into the table entry of the PHY this driver attaches,
and into no other. The chip has one PHY interrupt, and on 7801
phy_mask is 0, so other PHYs on the bus keep what the bus gave them.
The address is known only after the scan, so the write to phydev->irq
stays.

Found going through the drivers that keep a PHY interrupt outside the
bus table, so that the restore on detach later in this series has a
number to hand back here as well.

Assisted-by: LLM
Signed-off-by: Aleksei Sviridkin <f@xxxxxx>
---

Notes:
v13: write only the table entry of the attached PHY, after the scan,
instead of every entry before registration. The driver's number again
wins over a devicetree PHY interrupt, as it did before this series.
Andrew's Reviewed-by is dropped since the code changed.

The PHY_POLL branch is not reached: lan78xx_bind() fails earlier when
the interrupt mapping cannot be created.

Compile-tested only; I have no LAN78xx device. No Fixes: tag, since
nothing reads the bus table back until patch 3.

drivers/net/usb/lan78xx.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 5655941f1478..babd34cda374 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -2897,6 +2897,7 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)
phydev->irq = dev->domain_data.phyirq;
else
phydev->irq = PHY_POLL;
+ dev->mdiobus->irq[phydev->mdio.addr] = phydev->irq;
netdev_dbg(dev->net, "phydev->irq = %d\n", phydev->irq);

ret = phylink_connect_phy(dev->phylink, phydev);
--
2.53.0