Subject: [PATCH AUTOSEL 4.14 059/130] net: phy: dp83867: enable robust auto-mdix

From: Sasha Levin <[email-masked]>
Date: Tue, 10 Dec 2019 17:01:50 -0500

From: Grygorii Strashko <[email-masked]>

[ Upstream commit 5a7f08c2abb0efc9d17aff2fc75d6d3b85e622e4 ]

The link detection timeouts can be observed (or link might not be detected
at all) when dp83867 PHY is configured in manual mode (speed/duplex).

CFG3[9] Robust Auto-MDIX option allows to significantly improve link detection
in case dp83867 is configured in manual mode and reduce link detection
time.
As per DM: "If link partners are configured to operational modes that are
not supported by normal Auto MDI/MDIX mode (like Auto-Neg versus Force
100Base-TX or Force 100Base-TX versus Force 100Base-TX), this Robust Auto
MDI/MDIX mode allows MDI/MDIX resolution and prevents deadlock."

Hence, enable this option by default as there are no known reasons
not to do so.

Signed-off-by: Grygorii Strashko <[email-masked]>
Reviewed-by: Andrew Lunn <[email-masked]>
Reviewed-by: Florian Fainelli <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/phy/dp83867.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index e03e91d5f1b1b..0cbcced0870e6 100644
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -84,6 +84,10 @@
 #define DP83867_IO_MUX_CFG_IO_IMPEDANCE_MAX	0x0
 #define DP83867_IO_MUX_CFG_IO_IMPEDANCE_MIN	0x1f
 
+/* CFG3 bits */
+#define DP83867_CFG3_INT_OE			BIT(7)
+#define DP83867_CFG3_ROBUST_AUTO_MDIX		BIT(9)
+
 /* CFG4 bits */
 #define DP83867_CFG4_PORT_MIRROR_EN              BIT(0)
 
@@ -320,12 +324,13 @@ static int dp83867_config_init(struct phy_device *phydev)
 			return ret;
 	}
 
+	val = phy_read(phydev, DP83867_CFG3);
 	/* Enable Interrupt output INT_OE in CFG3 register */
-	if (phy_interrupt_is_valid(phydev)) {
-		val = phy_read(phydev, DP83867_CFG3);
-		val |= BIT(7);
-		phy_write(phydev, DP83867_CFG3, val);
-	}
+	if (phy_interrupt_is_valid(phydev))
+		val |= DP83867_CFG3_INT_OE;
+
+	val |= DP83867_CFG3_ROBUST_AUTO_MDIX;
+	phy_write(phydev, DP83867_CFG3, val);
 
 	if (dp83867->port_mirroring != DP83867_PORT_MIRROING_KEEP)
 		dp83867_config_port_mirroring(phydev);
-- 
2.20.1