net: fec: sharing MDIO for two enet controllers

On i.MX6SX, 6UL and 7D, there are two enet controllers each has a
MDIO port. But Some boards share one MDIO port for the two enets. So
introduce a configuration CONFIG_FEC_MXC_MDIO_BASE to indicate
the MDIO port for sharing.
In Kconfig, user needs enable CONFIG_FEC_MXC_SHARE_MDIO first to enter
the CONFIG_FEC_MXC_MDIO_BASE.

To i.MX28, adapt to use the new config

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>

drivers/net/Kconfig

@@ -155,9 +155,20 @@ config ETHOC
 	help
 	  This MAC is present in OpenRISC and Xtensa XTFPGA boards.
 
+config FEC_MXC_SHARE_MDIO
+	bool "Share the MDIO bus for FEC controller"
+	depends on FEC_MXC
+
+config FEC_MXC_MDIO_BASE
+	hex "MDIO base address for the FEC controller"
+	depends on FEC_MXC_SHARE_MDIO
+	help
+	  This specifies the MDIO registers base address. It is used when
+	  two FEC controllers share MDIO bus.
+
 config FEC_MXC
 	bool "FEC Ethernet controller"
-	depends on MX5 || MX6
+	depends on MX5 || MX6 || MX7
 	help
 	  This driver supports the 10/100 Fast Ethernet controller for
 	  NXP i.MX processors.

drivers/net/fec_mxc.c

@@ -1146,12 +1146,12 @@ int fecmxc_initialize_multi(bd_t *bd, int dev_id, int phy_id, uint32_t addr)
 #endif
 	int ret;
 
-#ifdef CONFIG_MX28
+#ifdef CONFIG_FEC_MXC_MDIO_BASE
 	/*
 	 * The i.MX28 has two ethernet interfaces, but they are not equal.
 	 * Only the first one can access the MDIO bus.
 	 */
-	base_mii = MXS_ENET0_BASE;
+	base_mii = CONFIG_FEC_MXC_MDIO_BASE;
 #else
 	base_mii = addr;
 #endif
@@ -1273,7 +1273,11 @@ static int fecmxc_probe(struct udevice *dev)
 	fec_reg_setup(priv);
 
 	priv->dev_id = dev->seq;
+#ifdef CONFIG_FEC_MXC_MDIO_BASE
+	bus = fec_get_miibus((ulong)CONFIG_FEC_MXC_MDIO_BASE, dev->seq);
+#else
 	bus = fec_get_miibus((ulong)priv->eth, dev->seq);
+#endif
 	if (!bus) {
 		ret = -ENOMEM;
 		goto err_mii;

include/configs/mx28evk.h

@@ -65,6 +65,7 @@
 /* FEC Ethernet on SoC */
 #ifdef	CONFIG_CMD_NET
 #define CONFIG_FEC_MXC
+#define CONFIG_FEC_MXC_MDIO_BASE MXS_ENET0_BASE
 #define CONFIG_MX28_FEC_MAC_IN_OCOTP
 #endif