[RFC net-next 1/2] net: phy: allow mdio bus to probe for c45 devices before c22

[Wong Vee Khee]

Some MAC controllers that is able to pair with  external PHY devices
such as the Synopsys MAC Controller (STMMAC) support both Clause-22 and
Clause-45 access.

When paired with PHY devices that only accessible via Clause-45, such as
the Marvell 88E2110, any attempts to access the PHY devices via
Clause-22 will get a PHY ID of all zeroes.

To fix this, we introduce MDIOBUS_C45_C22 which the MAC controller will
try with Clause-45 access before going to Clause-22.

Signed-off-by: Wong Vee Khee <vee.khee.wong@xxxxxxxxxxxxxxx>
---
 include/linux/phy.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/phy.h b/include/linux/phy.h
index 60d2b26026a2..9b0e2c76e19b 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -368,6 +368,7 @@ struct mii_bus {
 		MDIOBUS_C22,
 		MDIOBUS_C45,
 		MDIOBUS_C22_C45,
+		MDIOBUS_C45_C22,
 	} probe_capabilities;
 
 	/** @shared_lock: protect access to the shared element */
-- 
2.25.1