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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        =?UTF-8?q?M=C3=A5ns=20Rullg=C3=A5rd?= <mans@mansr.com>,
        Andre Edich <andre.edich@microchip.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 480/677] net: phy: lan87xx: fix access to wrong register of LAN87xx
Date:   Wed, 12 May 2021 16:48:46 +0200
Message-Id: <20210512144853.308026270@linuxfoundation.org>
In-Reply-To: <20210512144837.204217980@linuxfoundation.org>
References: <20210512144837.204217980@linuxfoundation.org>
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From: Andre Edich <andre.edich@microchip.com>

[ Upstream commit fdb5cc6ab3b6a1c0122d3644a63ef9dc7a610d35 ]

The function lan87xx_config_aneg_ext was introduced to configure
LAN95xxA but as well writes to undocumented register of LAN87xx.
This fix prevents that access.

The function lan87xx_config_aneg_ext gets more suitable for the new
behavior name.

Reported-by: Måns Rullgård <mans@mansr.com>
Fixes: 05b35e7eb9a1 ("smsc95xx: add phylib support")
Signed-off-by: Andre Edich <andre.edich@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/phy/smsc.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index ddb78fb4d6dc..d8cac02a79b9 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -185,10 +185,13 @@ static int lan87xx_config_aneg(struct phy_device *phydev)
 	return genphy_config_aneg(phydev);
 }
 
-static int lan87xx_config_aneg_ext(struct phy_device *phydev)
+static int lan95xx_config_aneg_ext(struct phy_device *phydev)
 {
 	int rc;
 
+	if (phydev->phy_id != 0x0007c0f0) /* not (LAN9500A or LAN9505A) */
+		return lan87xx_config_aneg(phydev);
+
 	/* Extend Manual AutoMDIX timer */
 	rc = phy_read(phydev, PHY_EDPD_CONFIG);
 	if (rc < 0)
@@ -441,7 +444,7 @@ static struct phy_driver smsc_phy_driver[] = {
 	.read_status	= lan87xx_read_status,
 	.config_init	= smsc_phy_config_init,
 	.soft_reset	= smsc_phy_reset,
-	.config_aneg	= lan87xx_config_aneg_ext,
+	.config_aneg	= lan95xx_config_aneg_ext,
 
 	/* IRQ related */
 	.config_intr	= smsc_phy_config_intr,
-- 
2.30.2