netdev - [PATCH 2/2 net] lan78xx: workaround of forced 100 Full/Half duplex mode error

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Message-ID: <9235D6609DB808459E95D78E17F2E43D408987FF@CHN-SV-EXMX02.mchp-main.com>
Date:	Mon, 25 Apr 2016 22:22:36 +0000
From:	<Woojung.Huh@...rochip.com>
To:	<davem@...emloft.net>
CC:	<netdev@...r.kernel.org>, <UNGLinuxDriver@...rochip.com>
Subject: [PATCH 2/2 net] lan78xx: workaround of forced 100 Full/Half duplex
 mode error

From: Woojung Huh <woojung.huh@...rochip.com>

At forced 100 Full & Half duplex mode, chip may fail to set mode correctly
when cable is switched between long(~50+m) and short one.
As workaround, set to 10 before setting to 100 at forced 100 F/H mode.

Signed-off-by: Woojung Huh <woojung.huh@...rochip.com>
---
 drivers/net/usb/lan78xx.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 0460b81..f64778a 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -1804,7 +1804,34 @@ static void lan78xx_remove_mdio(struct lan78xx_net *dev)
 
 static void lan78xx_link_status_change(struct net_device *net)
 {
-	/* nothing to do */
+	struct phy_device *phydev = net->phydev;
+	int ret, temp;
+
+	/* At forced 100 F/H mode, chip may fail to set mode correctly
+	 * when cable is switched between long(~50+m) and short one.
+	 * As workaround, set to 10 before setting to 100
+	 * at forced 100 F/H mode.
+	 */
+	if (!phydev->autoneg && (phydev->speed == 100)) {
+		/* disable phy interrupt */
+		temp = phy_read(phydev, LAN88XX_INT_MASK);
+		temp &= ~LAN88XX_INT_MASK_MDINTPIN_EN_;
+		ret = phy_write(phydev, LAN88XX_INT_MASK, temp);
+
+		temp = phy_read(phydev, MII_BMCR);
+		temp &= ~(BMCR_SPEED100 | BMCR_SPEED1000);
+		phy_write(phydev, MII_BMCR, temp); /* set to 10 first */
+		temp |= BMCR_SPEED100;
+		phy_write(phydev, MII_BMCR, temp); /* set to 100 later */
+
+		/* clear pending interrupt generated while workaround */
+		temp = phy_read(phydev, LAN88XX_INT_STS);
+
+		/* enable phy interrupt back */
+		temp = phy_read(phydev, LAN88XX_INT_MASK);
+		temp |= LAN88XX_INT_MASK_MDINTPIN_EN_;
+		ret = phy_write(phydev, LAN88XX_INT_MASK, temp);
+	}
 }
 
 static int lan78xx_phy_init(struct lan78xx_net *dev)
-- 
2.8.1