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Subject[PATCH] net: phy: marvell: Fix bits clear bug
Date
The correct way to clear bits before setting some of them is using
"& = ~BIT_MASK".
The wrong operation "& = BIT_MASK" will clear other bits.

m88e1116r_config_init() calls marvell_set_polarity() to config
MDI crossover mode by modifying reg MII_M1011_PHY_SCR, then it
calls marvell_set_downshift() to config downshift by modifying
the same reg. According to the bug, marvell_set_downshift()
clears other bits and set MDI Crossover Mode to Manual MDI
configuration. If we connect two devices both using this driver
with a wrong Ethernet cable, they can't automatically adjust
their crossover mode. Finally they fail to link.

Signed-off-by: Hansen Yang <yanghansen1@163.com>
---
drivers/net/phy/marvell.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index a7796134e3be..6ab8fe339043 100644
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -282,7 +282,7 @@ static int marvell_set_downshift(struct phy_device *phydev, bool enable,
if (reg < 0)
return reg;

- reg &= MII_M1011_PHY_SRC_DOWNSHIFT_MASK;
+ reg &= ~MII_M1011_PHY_SRC_DOWNSHIFT_MASK;
reg |= ((retries - 1) << MII_M1011_PHY_SCR_DOWNSHIFT_SHIFT);
if (enable)
reg |= MII_M1011_PHY_SCR_DOWNSHIFT_EN;
--
2.17.1

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