net: phy: marvell: add sleep time after enabling the loopback bit

Sleep time is added to ensure the phy to be ready after loopback
bit was set. This to prevent the phy loopback test from failing.

Fixes: 020a45aff119 ("net: phy: marvell: add Marvell specific PHY loopback")
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Signed-off-by: Aminuddin Jamaluddin <aminuddin.jamaluddin@intel.com>
Link: https://lore.kernel.org/r/20221114065302.10625-1-aminuddin.jamaluddin@intel.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index 2810f4f9da0ccc8f5c3aa183f06edc336b64c5c1..0d706ee266afd2580afbeb2112ef4d1d5c3fc790 100644 (file)
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -2015,14 +2015,16 @@ static int m88e1510_loopback(struct phy_device *phydev, bool enable)
                if (err < 0)
                        return err;
 
-               /* FIXME: Based on trial and error test, it seem 1G need to have
-                * delay between soft reset and loopback enablement.
-                */
-               if (phydev->speed == SPEED_1000)
-                       msleep(1000);
+               err = phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK,
+                                BMCR_LOOPBACK);
 
-               return phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK,
-                                 BMCR_LOOPBACK);
+               if (!err) {
+                       /* It takes some time for PHY device to switch
+                        * into/out-of loopback mode.
+                        */
+                       msleep(1000);
+               }
+               return err;
        } else {
                err = phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK, 0);
                if (err < 0)