From 3b09a3fb35079106fd490241bdc8e0c31434be00 Mon Sep 17 00:00:00 2001
From: Robert Hancock <hancock@sedsystems.ca>
Date: Thu, 6 Jun 2019 16:28:21 -0600
Subject: [PATCH] net: axienet: Fix MDIO bus parent node detection
This driver was previously using the parent node of the specified PHY
node as the device node to register the MDIO bus on. Andrew Lunn
pointed out this is wrong as the PHY node is potentially not even
underneath the MDIO bus for the current device instance. Find the MDIO
node explicitly by looking it up by name under the controller's device
node instead.
This could potentially break existing device trees if they don't use
"mdio" as the name for the MDIO bus, but I did not find any with various
searches and Xilinx's examples all use mdio as the name so it seems like
this should be relatively safe.
Signed-off-by: Robert Hancock <hancock@sedsystems.ca>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c b/drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c
index 7106810793d5f..435ed308d9902 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_mdio.c
@@ -228,7 +228,6 @@ int axienet_mdio_setup(struct axienet_local *lp)
if (!bus)
return -ENOMEM;
- mdio_node = of_get_parent(lp->phy_node);
snprintf(bus->id, MII_BUS_ID_SIZE, "axienet-%.8llx",
(unsigned long long)lp->regs_start);
@@ -239,7 +238,9 @@ int axienet_mdio_setup(struct axienet_local *lp)
bus->parent = lp->dev;
lp->mii_bus = bus;
+ mdio_node = of_get_child_by_name(lp->dev->of_node, "mdio");
ret = of_mdiobus_register(bus, mdio_node);
+ of_node_put(mdio_node);
if (ret) {
mdiobus_free(bus);
lp->mii_bus = NULL;
--
2.30.2