arm: socfpga: set skew settings for ethernet phy

Set the PHY skew settings for the ethernet phy on the SOCFPGA Cyclone5
hardware.

Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Vince Bridgers <vbridger@opensource.altera.com>
Cc: Pavel Machek <pavel@denx.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@ti.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Wolfgang Denk <wd@denx.de>

board/altera/socfpga/socfpga_cyclone5.c

@@ -12,7 +12,9 @@
 #include <usb/s3c_udc.h>
 #include <usb_mass_storage.h>
 
+#include <micrel.h>
 #include <netdev.h>
+#include <phy.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -44,6 +46,20 @@ int board_init(void)
 	return 0;
 }
 
+int board_phy_config(struct phy_device *phydev)
+{
+	/*
+	 * These skew settings for the KSZ9021 ethernet phy is required for ethernet
+	 * to work reliably on most flavors of cyclone5 boards.
+	 */
+	ksz9021_phy_extended_write(phydev, MII_KSZ9021_EXT_RGMII_RX_DATA_SKEW,
+				   0x0);
+	ksz9021_phy_extended_write(phydev, MII_KSZ9021_EXT_RGMII_TX_DATA_SKEW,
+				   0x0);
+	ksz9021_phy_extended_write(phydev, MII_KSZ9021_EXT_RGMII_CLOCK_SKEW,
+				   0xf0f0);
+}
+
 #ifdef CONFIG_USB_GADGET
 struct s3c_plat_otg_data socfpga_otg_data = {
 	.regs_otg	= CONFIG_USB_DWC2_REG_ADDR,