[U-Boot] [PATCH v3 1/4] net: phy: Optionally force master mode for RTL PHY

[Michael Haas]

This patch introduces CONFIG_RTL8211X_PHY_FORCE_MASTER. If this
define is set, RTL8211x PHYs will have their 1000BASE-T
master/slave autonegotiation disabled and forced to master mode.

This is helpful for PHYs like the RTL8211C which produce unstable links
in slave mode. Such problems have been found on the A20-Olimex-SOM-EVB
and A20-OLinuXino-Lime2.

There is no proper way to identify affected PHYs as the RTL8211C shares
its UID with the RTL8211B. Thus, this fixes requires the introduction of
an #ifdef.

CC: fradav at gmail.com
CC: merker at debian.org
CC: hdegoede at redhat.com
CC: ijc at hellion.org.uk
CC: joe.hershberger at ni.com
Signed-off-by: Michael Haas <haas at computerlinguist.org>
---

Changes in v3:
 - Remove incorrect detection of RTL8211CL and use #ifdef instead
   (thanks to Karsten Merker)
 - Introduced constants for register bits

Changes in v2:
 - Removed accidental inclusion of Karsten's patch in my first submission of this series.
 - Fix a typo in the code: 6 -> &

 drivers/net/phy/realtek.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index 259a87f..359ec50 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -12,6 +12,10 @@
 
 #define PHY_AUTONEGOTIATE_TIMEOUT 5000
 
+/* RTL8211x 1000BASE-T Control Register */
+#define MIIM_RTL8211x_CTRL1000T_MSCE (1 << 12);
+#define MIIM_RTL8211X_CTRL1000T_MASTER (1 << 11);
+
 /* RTL8211x PHY Status Register */
 #define MIIM_RTL8211x_PHY_STATUS       0x11
 #define MIIM_RTL8211x_PHYSTAT_SPEED    0xc000
@@ -53,7 +57,14 @@ static int rtl8211x_config(struct phy_device *phydev)
 	 */
 	phy_write(phydev, MDIO_DEVAD_NONE, MIIM_RTL8211x_PHY_INER,
 		  MIIM_RTL8211x_PHY_INTR_DIS);
-
+#ifdef CONFIG_RTL8211X_PHY_FORCE_MASTER
+	unsigned int reg = phy_read(phydev, MDIO_DEVAD_NONE, MII_CTRL1000);
+	/* force manual master/slave configuration */
+	reg |= MIIM_RTL8211x_CTRL1000T_MSCE;
+	/* force master mode */
+	reg |= MIIM_RTL8211X_CTRL1000T_MASTER;
+	phy_write(phydev, MDIO_DEVAD_NONE, MII_CTRL1000, reg);
+#endif
 	/* read interrupt status just to clear it */
 	phy_read(phydev, MDIO_DEVAD_NONE, MIIM_RTL8211x_PHY_INER);
 
-- 
2.7.2