From: Saravana Kannan saravanak@google.com
[ Upstream commit 04f41c68f18886aea5afc68be945e7195ea1d598 ]
There are many instances of PHYs that depend on a switch to supply a resource (Eg: interrupts). Switches also expects the PHYs to be probed by their specific drivers as soon as they are added. If that doesn't happen, then the switch would force the use of generic PHY drivers for the PHY even if the PHY might have specific driver available.
fw_devlink=on by design can cause delayed probes of PHY. To avoid, this we need to set the FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD for the switch's fwnode before the PHYs are added. The most generic way to do this is to set this flag for the parent of MDIO busses which is typically the switch.
For more context: https://lore.kernel.org/lkml/YTll0i6Rz3WAAYzs@lunn.ch/#t
Fixes: ea718c699055 ("Revert "Revert "driver core: Set fw_devlink=on by default""") Suggested-by: Andrew Lunn andrew@lunn.ch Signed-off-by: Saravana Kannan saravanak@google.com Link: https://lore.kernel.org/r/20210915170940.617415-4-saravanak@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/phy/mdio_bus.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index 53f034fc2ef7..ee8313a4ac71 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -525,6 +525,10 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) NULL == bus->read || NULL == bus->write) return -EINVAL;
+ if (bus->parent && bus->parent->of_node) + bus->parent->of_node->fwnode.flags |= + FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD; + BUG_ON(bus->state != MDIOBUS_ALLOCATED && bus->state != MDIOBUS_UNREGISTERED);