netdev - [PATCH] net: phy: dp83867: Set FORCE_LINK

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Date:   Tue, 14 Jan 2020 12:24:25 +0100
From:   Michael Grzeschik <m.grzeschik@...gutronix.de>
To:     netdev@...r.kernel.org
Cc:     andrew@...n.ch, f.fainelli@...il.com, hkallweit1@...il.com,
        kernel@...gutronix.de
Subject: [PATCH] net: phy: dp83867: Set FORCE_LINK_GOOD do default after reset

According to the Datasheet this bit should be 0 (Normal operation) in
default. With the FORCE_LINK_GOOD bit set, it is not possible to get a
link. This patch sets FORCE_LINK_GOOD to the default value after
resetting the phy.

Signed-off-by: Michael Grzeschik <m.grzeschik@...gutronix.de>
---
 drivers/net/phy/dp83867.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index adda0d0eab800..60a09fabf41d1 100644
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -99,6 +99,7 @@
 #define DP83867_PHYCR_TX_FIFO_DEPTH_MASK	GENMASK(15, 14)
 #define DP83867_PHYCR_RX_FIFO_DEPTH_MASK	GENMASK(13, 12)
 #define DP83867_PHYCR_RESERVED_MASK		BIT(11)
+#define DP83867_PHYCR_FORCE_LINK_GOOD		BIT(10)
 
 /* RGMIIDCTL bits */
 #define DP83867_RGMII_TX_CLK_DELAY_MAX		0xf
@@ -627,7 +628,7 @@ static int dp83867_config_init(struct phy_device *phydev)
 
 static int dp83867_phy_reset(struct phy_device *phydev)
 {
-	int err;
+	int val, err;
 
 	err = phy_write(phydev, DP83867_CTRL, DP83867_SW_RESET);
 	if (err < 0)
@@ -635,6 +636,16 @@ static int dp83867_phy_reset(struct phy_device *phydev)
 
 	usleep_range(10, 20);
 
+	/* After reset FORCE_LINK_GOOD bit is set. Although the
+	 * default value should be unset. Disable FORCE_LINK_GOOD
+	 * for the phy to work properly.
+	 */
+	val = phy_read(phydev, MII_DP83867_PHYCTRL);
+	if (val & DP83867_PHYCR_FORCE_LINK_GOOD) {
+		val &= ~(DP83867_PHYCR_FORCE_LINK_GOOD);
+		phy_write(phydev, MII_DP83867_PHYCTRL, val);
+	}
+
 	return 0;
 }
 
-- 
2.25.0.rc1