@@ -767,7 +767,10 @@ int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
lockdep_assert_held_once(&bus->mdio_lock);
- retval = bus->read(bus, addr, regnum);
+ if (bus->read)
+ retval = bus->read(bus, addr, regnum);
+ else
+ retval = -EOPNOTSUPP;
trace_mdio_access(bus, 1, addr, regnum, retval, retval);
mdiobus_stats_acct(&bus->stats[addr], true, retval);
@@ -793,7 +796,10 @@ int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
lockdep_assert_held_once(&bus->mdio_lock);
- err = bus->write(bus, addr, regnum, val);
+ if (bus->write)
+ err = bus->write(bus, addr, regnum, val);
+ else
+ err = -EOPNOTSUPP;
trace_mdio_access(bus, 0, addr, regnum, val, err);
mdiobus_stats_acct(&bus->stats[addr], false, err);
When performing a C22 operation, check that the bus driver actually provides the methods, and return -EOPNOTSUPP if not. C45 only busses do exist, and in future their C22 methods will be NULL. Signed-off-by: Andrew Lunn <andrew@lunn.ch> --- drivers/net/phy/mdio_bus.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)