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From:   Wong Vee Khee <vee.khee.wong@linux.intel.com>
To:     Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC net-next 1/2] net: phy: allow mdio bus to probe for c45 devices before c22
Date:   Tue, 25 May 2021 13:58:39 +0800
Message-Id: <20210525055839.22496-1-vee.khee.wong@linux.intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@linux.intel.com>
---
 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