net/phy: extra delay only for RGMII interfaces for IC+ IP 1001

The extra delay of 2ns to adjust RX clock phase is actually needed
in RGMII mode. Tested on the HDK7108 (STx7108c2).

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/icplus.c

@@ -128,12 +128,15 @@ static int ip1001_config_init(struct phy_device *phydev)
 	if (c < 0)
 		return c;
 
-	/* Additional delay (2ns) used to adjust RX clock phase
-	 * at GMII/ RGMII interface */
-	c = phy_read(phydev, IP10XX_SPEC_CTRL_STATUS);
-	c |= IP1001_PHASE_SEL_MASK;
+	if (phydev->interface == PHY_INTERFACE_MODE_RGMII) {
+		/* Additional delay (2ns) used to adjust RX clock phase
+		 * at RGMII interface */
+		c = phy_read(phydev, IP10XX_SPEC_CTRL_STATUS);
+		c |= IP1001_PHASE_SEL_MASK;
+		c = phy_write(phydev, IP10XX_SPEC_CTRL_STATUS, c);
+	}
 
-	return phy_write(phydev, IP10XX_SPEC_CTRL_STATUS, c);
+	return c;
 }
 
 static int ip101a_config_init(struct phy_device *phydev)