[PATCH] net: phy: dp83tg720: wake up PHYs in managed mode

[Oleksij Rempel <o.rempel@pengutronix.de>]

From: David Jander <david@protonic.nl>

In case this PHY is bootstrapped for managed mode, we need to manually
wake it. Otherwise no link will be detected.

Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/phy/dp83tg720.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/net/phy/dp83tg720.c b/drivers/net/phy/dp83tg720.c
index 0571f4cb52..d57985539d 100644
--- a/drivers/net/phy/dp83tg720.c
+++ b/drivers/net/phy/dp83tg720.c
@@ -21,6 +21,11 @@
 #define DP83TG720S_PHY_RESET			0x1f
 #define DP83TG720S_HW_RESET			BIT(15)
 
+#define DP83TG720S_LPS_CFG3			0x18c
+/* Power modes are documented as bitfields but used as values */
+/* Power Mode 0 is Normal mode */
+#define DP83TG720S_LPS_CFG3_PWR_MODE_0		BIT(0)
+
 static int dp83tg720_config_rgmii_delay(struct phy_device *phydev)
 {
 	u16 rgmii_delay_mask;
@@ -54,6 +59,8 @@ static int dp83tg720_config_rgmii_delay(struct phy_device *phydev)
 
 static int dp83tg720_phy_init(struct phy_device *phydev)
 {
+	int ret = 0;
+
 	/* HW reset is needed to recover link if previous link was lost. SW
 	 * reset is not enough.
 	 */
@@ -62,10 +69,23 @@ static int dp83tg720_phy_init(struct phy_device *phydev)
 	phydev->supported = SUPPORTED_1000baseT_Full;
 	phydev->advertising = SUPPORTED_1000baseT_Full;
 
-	if (phy_interface_is_rgmii(phydev))
-		return dp83tg720_config_rgmii_delay(phydev);
+	/* According to the "DP83TG720R-Q1 1000BASE-T1 Automotive Ethernet PHY
+	 * datasheet (Rev. C)" - "T6.2 Post reset stabilization-time prior to
+	 * MDC preamble for register access is 1ms."
+	 */
+	mdelay(1);
 
-	return 0;
+	if (phy_interface_is_rgmii(phydev)) {
+		ret = dp83tg720_config_rgmii_delay(phydev);
+		if (ret)
+			return ret;
+	}
+
+	/* In case the PHY is bootstrapped in managed mode, we need to
+	 * wake it.
+	 */
+	return phy_write_mmd(phydev, MDIO_MMD_VEND2, DP83TG720S_LPS_CFG3,
+			     DP83TG720S_LPS_CFG3_PWR_MODE_0);
 }
 
 static int dp83tg720_read_status(struct phy_device *phydev)
-- 
2.39.2