From 9581895b37fe3a8c83e102cc491c6c7996df2934 Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Tue, 17 Aug 2021 20:38:03 -0700 Subject: [PATCH] net: mdio-mux: Handle -EPROBE_DEFER correctly [ 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+-JtfH7H9biJEGJtijuPVN0V5dUKUAB3A@mail.gmail.com/#t Signed-off-by: Saravana Kannan Reviewed-by: Andrew Lunn Acked-by: Marc Zyngier Tested-by: Marc Zyngier Acked-by: Kevin Hilman Tested-by: Kevin Hilman Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/mdio/mdio-mux.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/mdio/mdio-mux.c b/drivers/net/mdio/mdio-mux.c index d6ed9033339c4..3dde0c2b3e097 100644 --- a/drivers/net/mdio/mdio-mux.c +++ b/drivers/net/mdio/mdio-mux.c @@ -175,11 +175,15 @@ 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;