ARM: i.MX6: Add OF configuration support for ksz9031

Adds support for ksz9031 PAD skew configuration over devicetree.
Signed-off-by: Hubert Chaumette <hchaumette@adeneo-embedded.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/micrel.c

@@ -283,6 +283,110 @@ static int ksz9021_config_init(struct phy_device *phydev)
 	return 0;
 }
 
+#define MII_KSZ9031RN_MMD_CTRL_REG	0x0d
+#define MII_KSZ9031RN_MMD_REGDATA_REG	0x0e
+#define OP_DATA				1
+#define KSZ9031_PS_TO_REG		60
+
+/* Extended registers */
+#define MII_KSZ9031RN_CONTROL_PAD_SKEW	4
+#define MII_KSZ9031RN_RX_DATA_PAD_SKEW	5
+#define MII_KSZ9031RN_TX_DATA_PAD_SKEW	6
+#define MII_KSZ9031RN_CLK_PAD_SKEW	8
+
+static int ksz9031_extended_write(struct phy_device *phydev,
+				  u8 mode, u32 dev_addr, u32 regnum, u16 val)
+{
+	phy_write(phydev, MII_KSZ9031RN_MMD_CTRL_REG, dev_addr);
+	phy_write(phydev, MII_KSZ9031RN_MMD_REGDATA_REG, regnum);
+	phy_write(phydev, MII_KSZ9031RN_MMD_CTRL_REG, (mode << 14) | dev_addr);
+	return phy_write(phydev, MII_KSZ9031RN_MMD_REGDATA_REG, val);
+}
+
+static int ksz9031_extended_read(struct phy_device *phydev,
+				 u8 mode, u32 dev_addr, u32 regnum)
+{
+	phy_write(phydev, MII_KSZ9031RN_MMD_CTRL_REG, dev_addr);
+	phy_write(phydev, MII_KSZ9031RN_MMD_REGDATA_REG, regnum);
+	phy_write(phydev, MII_KSZ9031RN_MMD_CTRL_REG, (mode << 14) | dev_addr);
+	return phy_read(phydev, MII_KSZ9031RN_MMD_REGDATA_REG);
+}
+
+static int ksz9031_of_load_skew_values(struct phy_device *phydev,
+				       struct device_node *of_node,
+				       u16 reg, size_t field_sz,
+				       char *field[], u8 numfields)
+{
+	int val[4] = {-1, -2, -3, -4};
+	int matches = 0;
+	u16 mask;
+	u16 maxval;
+	u16 newval;
+	int i;
+
+	for (i = 0; i < numfields; i++)
+		if (!of_property_read_u32(of_node, field[i], val + i))
+			matches++;
+
+	if (!matches)
+		return 0;
+
+	if (matches < numfields)
+		newval = ksz9031_extended_read(phydev, OP_DATA, 2, reg);
+	else
+		newval = 0;
+
+	maxval = (field_sz == 4) ? 0xf : 0x1f;
+	for (i = 0; i < numfields; i++)
+		if (val[i] != -(i + 1)) {
+			mask = 0xffff;
+			mask ^= maxval << (field_sz * i);
+			newval = (newval & mask) |
+				(((val[i] / KSZ9031_PS_TO_REG) & maxval)
+					<< (field_sz * i));
+		}
+
+	return ksz9031_extended_write(phydev, OP_DATA, 2, reg, newval);
+}
+
+static int ksz9031_config_init(struct phy_device *phydev)
+{
+	struct device *dev = &phydev->dev;
+	struct device_node *of_node = dev->of_node;
+	char *clk_skews[2] = {"rxc-skew-ps", "txc-skew-ps"};
+	char *rx_data_skews[4] = {
+		"rxd0-skew-ps", "rxd1-skew-ps",
+		"rxd2-skew-ps", "rxd3-skew-ps"
+	};
+	char *tx_data_skews[4] = {
+		"txd0-skew-ps", "txd1-skew-ps",
+		"txd2-skew-ps", "txd3-skew-ps"
+	};
+	char *control_skews[2] = {"txen-skew-ps", "rxdv-skew-ps"};
+
+	if (!of_node && dev->parent->of_node)
+		of_node = dev->parent->of_node;
+
+	if (of_node) {
+		ksz9031_of_load_skew_values(phydev, of_node,
+				MII_KSZ9031RN_CLK_PAD_SKEW, 5,
+				clk_skews, 2);
+
+		ksz9031_of_load_skew_values(phydev, of_node,
+				MII_KSZ9031RN_CONTROL_PAD_SKEW, 4,
+				control_skews, 2);
+
+		ksz9031_of_load_skew_values(phydev, of_node,
+				MII_KSZ9031RN_RX_DATA_PAD_SKEW, 4,
+				rx_data_skews, 4);
+
+		ksz9031_of_load_skew_values(phydev, of_node,
+				MII_KSZ9031RN_TX_DATA_PAD_SKEW, 4,
+				tx_data_skews, 4);
+	}
+	return 0;
+}
+
 #define KSZ8873MLL_GLOBAL_CONTROL_4	0x06
 #define KSZ8873MLL_GLOBAL_CONTROL_4_DUPLEX	(1 << 6)
 #define KSZ8873MLL_GLOBAL_CONTROL_4_SPEED	(1 << 4)
@@ -469,7 +573,7 @@ static struct phy_driver ksphy_driver[] = {
 	.features	= (PHY_GBIT_FEATURES | SUPPORTED_Pause
 				| SUPPORTED_Asym_Pause),
 	.flags		= PHY_HAS_MAGICANEG | PHY_HAS_INTERRUPT,
-	.config_init	= kszphy_config_init,
+	.config_init	= ksz9031_config_init,
 	.config_aneg	= genphy_config_aneg,
 	.read_status	= genphy_read_status,
 	.ack_interrupt	= kszphy_ack_interrupt,