net: dsa: mv88e6xxx: add port's RGMII delay setter

Some chips such as 88E6352 and 88E6390 can be programmed to add delays
to RXCLK for IND inputs or to GTXCLK for OUTD outputs when port is in
RGMII mode.

Add a port function to program such delays according to the provided PHY
interface mode.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 58 insertions, 0 deletions

diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index 17b54441b0e9..838068d2b581 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -35,6 +35,64 @@ int mv88e6xxx_port_write(struct mv88e6xxx_chip *chip, int port, int reg,
  * Link, Duplex and Flow Control have one force bit, one value bit.
  */
 
+static int mv88e6xxx_port_set_rgmii_delay(struct mv88e6xxx_chip *chip, int port,
+					  phy_interface_t mode)
+{
+	u16 reg;
+	int err;
+
+	err = mv88e6xxx_port_read(chip, port, PORT_PCS_CTRL, &reg);
+	if (err)
+		return err;
+
+	reg &= ~(PORT_PCS_CTRL_RGMII_DELAY_RXCLK |
+		 PORT_PCS_CTRL_RGMII_DELAY_TXCLK);
+
+	switch (mode) {
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+		reg |= PORT_PCS_CTRL_RGMII_DELAY_RXCLK;
+		break;
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		reg |= PORT_PCS_CTRL_RGMII_DELAY_TXCLK;
+		break;
+	case PHY_INTERFACE_MODE_RGMII_ID:
+		reg |= PORT_PCS_CTRL_RGMII_DELAY_RXCLK |
+			PORT_PCS_CTRL_RGMII_DELAY_TXCLK;
+		break;
+	default:
+		/* no delay */
+		break;
+	}
+
+	err = mv88e6xxx_port_write(chip, port, PORT_PCS_CTRL, reg);
+	if (err)
+		return err;
+
+	netdev_dbg(chip->ds->ports[port].netdev, "delay RXCLK %s, TXCLK %s\n",
+		   reg & PORT_PCS_CTRL_RGMII_DELAY_RXCLK ? "yes" : "no",
+		   reg & PORT_PCS_CTRL_RGMII_DELAY_TXCLK ? "yes" : "no");
+
+	return 0;
+}
+
+int mv88e6352_port_set_rgmii_delay(struct mv88e6xxx_chip *chip, int port,
+				   phy_interface_t mode)
+{
+	if (port < 5)
+		return -EOPNOTSUPP;
+
+	return mv88e6xxx_port_set_rgmii_delay(chip, port, mode);
+}
+
+int mv88e6390_port_set_rgmii_delay(struct mv88e6xxx_chip *chip, int port,
+				   phy_interface_t mode)
+{
+	if (port != 0)
+		return -EOPNOTSUPP;
+
+	return mv88e6xxx_port_set_rgmii_delay(chip, port, mode);
+}
+
 int mv88e6xxx_port_set_link(struct mv88e6xxx_chip *chip, int port, int link)
 {
 	u16 reg;