From: Andrew Lunn <andrew@lunn.ch>

Now that C45 uses its own read/write methods, the validation performed
when a bus is registers needs updating. All combinations of C22 and
C45 are supported, but both read and write methods must be provided,
read only busses are not supported etc.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
---
v2:
 - [al] be consistent with other checks
 - [mw] make the test a bit easier to read
v3:
 - [mw] use the original validation test style again but with double
   negation
---
 drivers/net/phy/mdio_bus.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index bde195864c17..c992a9fd8b01 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -526,8 +526,15 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner)
 	int i, err;
 	struct gpio_desc *gpiod;
 
-	if (NULL == bus || NULL == bus->name ||
-	    NULL == bus->read || NULL == bus->write)
+	if (!bus || !bus->name)
+		return -EINVAL;
+
+	/* An access method always needs both read and write operations */
+	if (!!bus->read != !!bus->write || !!bus->read_c45 != !!bus->write_c45)
+		return -EINVAL;
+
+	/* At least one method is mandatory */
+	if (!bus->read && !bus->read_c45)
 		return -EINVAL;
 
 	if (bus->parent && bus->parent->of_node)

-- 
2.30.2