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

From: Sasha Levin
Date: Tue Dec 10 2019 - 17:10:19 EST

From: Grygorii Strashko <grygorii.strashko@xxxxxx>

[ 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
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 <grygorii.strashko@xxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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_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)