[PATCH v4] Add OF bindings to Micrel ksz9021 PHY

[PATCH v4] Add OF bindings to Micrel ksz9021 PHY

[Sean Cross]

Some boards require custom parameters be passed to the Micrel PHY.
Allow these boards to specify custom timing parameters in the device
tree node.

Changes since v3:
 - Add an example of parameters on an mdio bus
 - Specify values in picoseconds rather than as register values

Changes since v2:
 - limited the scope to just ksz9021 rather than all PHYs

Changes since v1:
 - removed redefinition of registers and addresses 

Sean Cross (1):
  net/phy: micrel: Add OF configuration support for ksz9021

 .../devicetree/bindings/net/micrel-ksz9021.txt     |   19 ++++
 drivers/net/phy/micrel.c                           |  101 +++++++++++++++++++-
 2 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/net/micrel-ksz9021.txt

-- 
1.7.9.5

[PATCH v4] net/phy: micrel: Add OF configuration support for ksz9021

[Sean Cross]

Some boards require custom PHY configuration, for example due to trace
length differences.  Add the ability to configure these registers in
order to get the PHY to function on boards that need it.

Because PHYs are auto-detected based on MDIO device IDs, allow PHY
configuration to be specified in the parent Ethernet device node if no
PHY device node is present.

Signed-off-by: Sean Cross <xobs@kosagi.com>
---
 .../devicetree/bindings/net/micrel-ksz9021.txt     |   19 ++++
 drivers/net/phy/micrel.c                           |  101 +++++++++++++++++++-
 2 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/net/micrel-ksz9021.txt

diff --git a/Documentation/devicetree/bindings/net/micrel-ksz9021.txt b/Documentation/devicetree/bindings/net/micrel-ksz9021.txt
new file mode 100644
index 0000000..b3e5cd2
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/micrel-ksz9021.txt
@@ -0,0 +1,19 @@
+Micrel KSZ9021 Gigabit Ethernet PHY
+
+Some boards require special tuning values, particularly when it comes to
+clock delays.  You can specify clock delay values by adding
+micrel-specific properties to an Ethernet OF device node.
+
+Optional properties:
+- micrel,clk-control-pad-skew : Timing offset for the MII clock line
+- micrel,rx-data-pad-skew : Timing offset for the RX MII pad
+- micrel,tx-data-pad-skew : Timing offset for the TX MII pad
+
+Example:
+	&enet {
+		micrel,clk-control-pad-skew = <0xf0f0>;
+		micrel,rx-data-pad-skew = <0x0000>;
+		micrel,tx-data-pad-skew = <0xffff>;
+		status = "okay";
+	};
+
diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 2510435..3e60ed0 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -25,6 +25,7 @@
 #include <linux/module.h>
 #include <linux/phy.h>
 #include <linux/micrel_phy.h>
+#include <linux/of.h>
 
 /* Operation Mode Strap Override */
 #define MII_KSZPHY_OMSO				0x16
@@ -53,6 +54,18 @@
 #define KS8737_CTRL_INT_ACTIVE_HIGH		(1 << 14)
 #define KSZ8051_RMII_50MHZ_CLK			(1 << 7)
 
+/* Write/read to/from extended registers */
+#define MII_KSZPHY_EXTREG                       0x0b
+#define KSZPHY_EXTREG_WRITE                     0x8000
+
+#define MII_KSZPHY_EXTREG_WRITE                 0x0c
+#define MII_KSZPHY_EXTREG_READ                  0x0d
+
+/* Extended registers */
+#define MII_KSZPHY_CLK_CONTROL_PAD_SKEW         0x104
+#define MII_KSZPHY_RX_DATA_PAD_SKEW             0x105
+#define MII_KSZPHY_TX_DATA_PAD_SKEW             0x106
+
 static int ksz_config_flags(struct phy_device *phydev)
 {
 	int regval;
@@ -65,6 +78,20 @@ static int ksz_config_flags(struct phy_device *phydev)
 	return 0;
 }
 
+static int kszphy_extended_write(struct phy_device *phydev,
+                                 u32 regnum, u16 val)
+{
+	phy_write(phydev, MII_KSZPHY_EXTREG, KSZPHY_EXTREG_WRITE | regnum);
+	return phy_write(phydev, MII_KSZPHY_EXTREG_WRITE, val);
+}
+
+static int kszphy_extended_read(struct phy_device *phydev,
+                                 u32 regnum)
+{
+	phy_write(phydev, MII_KSZPHY_EXTREG, regnum);
+	return phy_read(phydev, MII_KSZPHY_EXTREG_READ);
+}
+
 static int kszphy_ack_interrupt(struct phy_device *phydev)
 {
 	/* bit[7..0] int status, which is a read and clear register. */
@@ -141,6 +168,78 @@ static int ks8051_config_init(struct phy_device *phydev)
 	return rc < 0 ? rc : 0;
 }
 
+static int ksz9021_load_values_from_of(struct phy_device *phydev,
+				       struct device_node *of_node, u16 reg,
+				       char *field1, char *field2,
+				       char *field3, char *field4)
+{
+	int val1 = -1;
+	int val2 = -2;
+	int val3 = -3;
+	int val4 = -4;
+	int newval;
+	int matches = 0;
+
+	if (!of_property_read_u32(of_node, field1, &val1))
+		matches++;
+
+	if (!of_property_read_u32(of_node, field2, &val2))
+		matches++;
+
+	if (!of_property_read_u32(of_node, field3, &val3))
+		matches++;
+
+	if (!of_property_read_u32(of_node, field4, &val4))
+		matches++;
+
+	if (!matches)
+		return 0;
+
+	if (matches < 4)
+		newval = kszphy_extended_read(phydev, reg);
+	else
+		newval = 0;
+
+	if (val1 != -1)
+		newval = ((newval & 0xfff0) | ((val1/200)&0xf) << 0);
+
+	if (val2 != -1)
+		newval = ((newval & 0xff0f) | ((val2/200)&0xf) << 4);
+
+	if (val3 != -1)
+		newval = ((newval & 0xf0ff) | ((val3/200)&0xf) << 8);
+
+	if (val4 != -1)
+		newval = ((newval & 0x0fff) | ((val4/200)&0xf) << 12);
+
+	return kszphy_extended_write(phydev, reg, newval);
+}
+
+static int ksz9021_config_init(struct phy_device *phydev)
+{
+	struct device *dev = &phydev->dev;
+	struct device_node *of_node = dev->of_node;
+
+	if (!of_node && dev->parent->of_node)
+		of_node = dev->parent->of_node;
+
+	if (of_node) {
+		ksz9021_load_values_from_of(phydev, of_node,
+				    MII_KSZPHY_CLK_CONTROL_PAD_SKEW,
+				    "txen-skew", "txc-skew",
+				    "rxdv-skew", "rxc-skew");
+		ksz9021_load_values_from_of(phydev, of_node,
+				    MII_KSZPHY_RX_DATA_PAD_SKEW,
+				    "rxd0-skew", "rxd1-skew",
+				    "rxd2-skew", "rxd3-skew");
+		ksz9021_load_values_from_of(phydev, of_node,
+				    MII_KSZPHY_TX_DATA_PAD_SKEW,
+				    "txd0-skew", "txd1-skew",
+				    "txd2-skew", "txd3-skew");
+	}
+	return 0;
+}
+
 #define KSZ8873MLL_GLOBAL_CONTROL_4	0x06
 #define KSZ8873MLL_GLOBAL_CONTROL_4_DUPLEX	(1 << 6)
 #define KSZ8873MLL_GLOBAL_CONTROL_4_SPEED	(1 << 4)
@@ -281,7 +380,7 @@ static struct phy_driver ksphy_driver[] = {
 	.name		= "Micrel KSZ9021 Gigabit PHY",
 	.features	= (PHY_GBIT_FEATURES | SUPPORTED_Pause),
 	.flags		= PHY_HAS_MAGICANEG | PHY_HAS_INTERRUPT,
-	.config_init	= kszphy_config_init,
+	.config_init	= ksz9021_config_init,
 	.config_aneg	= genphy_config_aneg,
 	.read_status	= genphy_read_status,
 	.ack_interrupt	= kszphy_ack_interrupt,
-- 
1.7.9.5