From 10ad63da5c036b2fd61600b43217cfa9b4d66f52 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Wed, 13 Dec 2023 17:27:12 +0200 Subject: net: mdio-mux: be compatible with parent buses which only support C45 After the mii_bus API conversion to a split read() / read_c45(), there might be MDIO parent buses which only populate the read_c45() and write_c45() function pointers but not the C22 variants. We haven't seen these in the wild paired with MDIO multiplexers, but Andrew points out we should treat the corner case. Link: https://lore.kernel.org/netdev/4ccd7dc9-b611-48aa-865f-68d3a1327ce8@lunn.ch/ Signed-off-by: Vladimir Oltean Reviewed-by: Andrew Lunn Link: https://lore.kernel.org/r/20231213152712.320842-3-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski --- drivers/net/mdio/mdio-mux.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/net/mdio/mdio-mux.c b/drivers/net/mdio/mdio-mux.c index e5dee7ad7c09..fe0e46bd7964 100644 --- a/drivers/net/mdio/mdio-mux.c +++ b/drivers/net/mdio/mdio-mux.c @@ -214,8 +214,10 @@ int mdio_mux_init(struct device *dev, snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x.%x", cb->mii_bus->name, pb->parent_id, v); cb->mii_bus->parent = dev; - cb->mii_bus->read = mdio_mux_read; - cb->mii_bus->write = mdio_mux_write; + if (parent_bus->read) + cb->mii_bus->read = mdio_mux_read; + if (parent_bus->write) + cb->mii_bus->write = mdio_mux_write; if (parent_bus->read_c45) cb->mii_bus->read_c45 = mdio_mux_read_c45; if (parent_bus->write_c45) -- cgit v1.2.3