net: phy: dp83867: introduce critical chip default init for non-of pl…

…atform

PHY driver dp83867 has rich supports for OF-platform to fine-tune the PHY
chip during phy configuration. However, for non-OF platform, certain PHY
tunable parameters such as IO impedance and RX & TX internal delays are
critical and should be initialized to its default during PHY driver probe.

Tested-by: Clement <clement@intel.com>
Signed-off-by: Lay, Kuan Loon <kuan.loon.lay@intel.com>
Co-developed-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Tested-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20211013065941.2124858-1-boon.leong.ong@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/dp83867.c

@@ -619,6 +619,25 @@ static int dp83867_of_init(struct phy_device *phydev)
 #else
 static int dp83867_of_init(struct phy_device *phydev)
 {
+	struct dp83867_private *dp83867 = phydev->priv;
+	u16 delay;
+
+	/* For non-OF device, the RX and TX ID values are either strapped
+	 * or take from default value. So, we init RX & TX ID values here
+	 * so that the RGMIIDCTL is configured correctly later in
+	 * dp83867_config_init();
+	 */
+	delay = phy_read_mmd(phydev, DP83867_DEVADDR, DP83867_RGMIIDCTL);
+	dp83867->rx_id_delay = delay & DP83867_RGMII_RX_CLK_DELAY_MAX;
+	dp83867->tx_id_delay = (delay >> DP83867_RGMII_TX_CLK_DELAY_SHIFT) &
+			       DP83867_RGMII_TX_CLK_DELAY_MAX;
+
+	/* Per datasheet, IO impedance is default to 50-ohm, so we set the
+	 * same here or else the default '0' means highest IO impedance
+	 * which is wrong.
+	 */
+	dp83867->io_impedance = DP83867_IO_MUX_CFG_IO_IMPEDANCE_MIN / 2;
+
 	return 0;
 }
 #endif /* CONFIG_OF_MDIO */