From: Saravana Kannan <saravanak@google.com> stable inclusion from linux-4.19.205 commit fed44f82ffa8443f4ddc5c269f1ab8f388fe9382 -------------------------------- [ Upstream commit 7bd0cef5dac685f09ef8b0b2a7748ff42d284dc7 ] When registering mdiobus children, if we get an -EPROBE_DEFER, we shouldn't ignore it and continue registering the rest of the mdiobus children. This would permanently prevent the deferring child mdiobus from working instead of reattempting it in the future. So, if a child mdiobus needs to be reattempted in the future, defer the entire mdio-mux initialization. This fixes the issue where PHYs sitting under the mdio-mux aren't initialized correctly if the PHY's interrupt controller is not yet ready when the mdio-mux is being probed. Additional context in the link below. Fixes: 0ca2997d1452 ("netdev/of/phy: Add MDIO bus multiplexer support.") Link: https://lore.kernel.org/lkml/CAGETcx95kHrv8wA-O+-JtfH7H9biJEGJtijuPVN0V5dUKU... Signed-off-by: Saravana Kannan <saravanak@google.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Acked-by: Marc Zyngier <maz@kernel.org> Tested-by: Marc Zyngier <maz@kernel.org> Acked-by: Kevin Hilman <khilman@baylibre.com> Tested-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/net/phy/mdio-mux.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c index bb7e3f12a0031..c16f875ed9ead 100644 --- a/drivers/net/phy/mdio-mux.c +++ b/drivers/net/phy/mdio-mux.c @@ -178,11 +178,15 @@ int mdio_mux_init(struct device *dev, cb->mii_bus->write = mdio_mux_write; r = of_mdiobus_register(cb->mii_bus, child_bus_node); if (r) { + mdiobus_free(cb->mii_bus); + if (r == -EPROBE_DEFER) { + ret_val = r; + goto err_loop; + } + devm_kfree(dev, cb); dev_err(dev, "Error: Failed to register MDIO bus for child %pOF\n", child_bus_node); - mdiobus_free(cb->mii_bus); - devm_kfree(dev, cb); } else { cb->next = pb->children; pb->children = cb; -- 2.25.1