net: phy: dp83867: perform soft reset and retain established link

[ Upstream commit da9ef50f545f86ffe6ff786174d26500c4db737a ]

Current logic is performing hard reset and causing the programmed
registers to be wiped out.

as per datasheet: https://www.ti.com/lit/ds/symlink/dp83867cr.pdf
8.6.26 Control Register (CTRL)

do SW_RESTART to perform a reset not including the registers,
If performed when link is already present,
it will drop the link and trigger re-auto negotiation.

Signed-off-by: Praneeth Bajjuri <praneeth@ti.com>
Signed-off-by: Geet Modi <geet.modi@ti.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index 69d3eac..c716074 100644 (file)
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -792,16 +792,12 @@ static int dp83867_phy_reset(struct phy_device *phydev)
 {
        int err;
 
-       err = phy_write(phydev, DP83867_CTRL, DP83867_SW_RESET);
+       err = phy_write(phydev, DP83867_CTRL, DP83867_SW_RESTART);
        if (err < 0)
                return err;
 
        usleep_range(10, 20);
 
-       /* After reset FORCE_LINK_GOOD bit is set. Although the
-        * default value should be unset. Disable FORCE_LINK_GOOD
-        * for the phy to work properly.
-        */
        return phy_modify(phydev, MII_DP83867_PHYCTRL,
                         DP83867_PHYCR_FORCE_LINK_GOOD, 0);
 }