net: phy: micrel: make sure the factory test bit is cleared

The KSZ8081 PHY has a factory test mode which is set at the de-assertion
of the hard reset based on the TXC pin. If a pull-down is missing, or if
the pin has a pull-up, the factory test mode should be cleared by
manually writing a 0 (according to the datasheet). This patch makes sure
this factory test bit is cleared in config_init().

Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
[nicolas.ferre@microchip.com: backport to 4.19]
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>

Author: atenart

drivers/net/phy/micrel.c

@@ -32,6 +32,7 @@
 
 /* Operation Mode Strap Override */
 #define MII_KSZPHY_OMSO				0x16
+#define KSZPHY_OMSO_FACTORY_TEST		BIT(15)
 #define KSZPHY_OMSO_B_CAST_OFF			BIT(9)
 #define KSZPHY_OMSO_NAND_TREE_ON		BIT(5)
 #define KSZPHY_OMSO_RMII_OVERRIDE		BIT(1)
@@ -339,6 +340,17 @@ static int ksz8041_config_aneg(struct phy_device *phydev)
 	return genphy_config_aneg(phydev);
 }
 
+static int ksz8081_config_init(struct phy_device *phydev)
+{
+	/* KSZPHY_OMSO_FACTORY_TEST is set at de-assertion of the reset line
+	 * based on the TXC pin. If a pull-down is missing, the factory test
+	 * mode should be cleared by manually writing a 0.
+	 */
+	phy_clear_bits(phydev, MII_KSZPHY_OMSO, KSZPHY_OMSO_FACTORY_TEST);
+
+	return kszphy_config_init(phydev);
+}
+
 static int ksz9021_load_values_from_of(struct phy_device *phydev,
 				       const struct device_node *of_node,
 				       u16 reg,
@@ -920,7 +932,7 @@ static struct phy_driver ksphy_driver[] = {
 	.flags		= PHY_HAS_INTERRUPT,
 	.driver_data	= &ksz8081_type,
 	.probe		= kszphy_probe,
-	.config_init	= kszphy_config_init,
+	.config_init	= ksz8081_config_init,
 	.ack_interrupt	= kszphy_ack_interrupt,
 	.config_intr	= kszphy_config_intr,
 	.get_sset_count = kszphy_get_sset_count,