net: dsa: microchip: lan937x: add phy read and write support

This patch add support for the writing and reading of the phy registers.
LAN937x uses the Vphy indirect addressing method for accessing the phys.

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 116 insertions, 0 deletions

diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
index e167a0c1ff85..5a2e14fe3cf3 100644
--- a/drivers/net/dsa/microchip/lan937x_main.c
+++ b/drivers/net/dsa/microchip/lan937x_main.c
@@ -28,6 +28,114 @@ static int lan937x_port_cfg(struct ksz_device *dev, int port, int offset,
 				  bits, set ? bits : 0);
 }
 
+static int lan937x_enable_spi_indirect_access(struct ksz_device *dev)
+{
+	u16 data16;
+	int ret;
+
+	/* Enable Phy access through SPI */
+	ret = lan937x_cfg(dev, REG_GLOBAL_CTRL_0, SW_PHY_REG_BLOCK, false);
+	if (ret < 0)
+		return ret;
+
+	ret = ksz_read16(dev, REG_VPHY_SPECIAL_CTRL__2, &data16);
+	if (ret < 0)
+		return ret;
+
+	/* Allow SPI access */
+	data16 |= VPHY_SPI_INDIRECT_ENABLE;
+
+	return ksz_write16(dev, REG_VPHY_SPECIAL_CTRL__2, data16);
+}
+
+static int lan937x_vphy_ind_addr_wr(struct ksz_device *dev, int addr, int reg)
+{
+	u16 addr_base = REG_PORT_T1_PHY_CTRL_BASE;
+	u16 temp;
+
+	/* get register address based on the logical port */
+	temp = PORT_CTRL_ADDR(addr, (addr_base + (reg << 2)));
+
+	return ksz_write16(dev, REG_VPHY_IND_ADDR__2, temp);
+}
+
+static int lan937x_internal_phy_write(struct ksz_device *dev, int addr, int reg,
+				      u16 val)
+{
+	unsigned int value;
+	int ret;
+
+	/* Check for internal phy port */
+	if (!dev->info->internal_phy[addr])
+		return -EOPNOTSUPP;
+
+	ret = lan937x_vphy_ind_addr_wr(dev, addr, reg);
+	if (ret < 0)
+		return ret;
+
+	/* Write the data to be written to the VPHY reg */
+	ret = ksz_write16(dev, REG_VPHY_IND_DATA__2, val);
+	if (ret < 0)
+		return ret;
+
+	/* Write the Write En and Busy bit */
+	ret = ksz_write16(dev, REG_VPHY_IND_CTRL__2,
+			  (VPHY_IND_WRITE | VPHY_IND_BUSY));
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read_poll_timeout(dev->regmap[1], REG_VPHY_IND_CTRL__2,
+				       value, !(value & VPHY_IND_BUSY), 10,
+				       1000);
+	if (ret < 0) {
+		dev_err(dev->dev, "Failed to write phy register\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int lan937x_internal_phy_read(struct ksz_device *dev, int addr, int reg,
+				     u16 *val)
+{
+	unsigned int value;
+	int ret;
+
+	/* Check for internal phy port, return 0xffff for non-existent phy */
+	if (!dev->info->internal_phy[addr])
+		return 0xffff;
+
+	ret = lan937x_vphy_ind_addr_wr(dev, addr, reg);
+	if (ret < 0)
+		return ret;
+
+	/* Write Read and Busy bit to start the transaction */
+	ret = ksz_write16(dev, REG_VPHY_IND_CTRL__2, VPHY_IND_BUSY);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read_poll_timeout(dev->regmap[1], REG_VPHY_IND_CTRL__2,
+				       value, !(value & VPHY_IND_BUSY), 10,
+				       1000);
+	if (ret < 0) {
+		dev_err(dev->dev, "Failed to read phy register\n");
+		return ret;
+	}
+
+	/* Read the VPHY register which has the PHY data */
+	return ksz_read16(dev, REG_VPHY_IND_DATA__2, val);
+}
+
+void lan937x_r_phy(struct ksz_device *dev, u16 addr, u16 reg, u16 *data)
+{
+	lan937x_internal_phy_read(dev, addr, reg, data);
+}
+
+void lan937x_w_phy(struct ksz_device *dev, u16 addr, u16 reg, u16 val)
+{
+	lan937x_internal_phy_write(dev, addr, reg, val);
+}
+
 int lan937x_reset_switch(struct ksz_device *dev)
 {
 	u32 data32;
@@ -111,6 +219,14 @@ void lan937x_config_cpu_port(struct dsa_switch *ds)
 int lan937x_setup(struct dsa_switch *ds)
 {
 	struct ksz_device *dev = ds->priv;
+	int ret;
+
+	/* enable Indirect Access from SPI to the VPHY registers */
+	ret = lan937x_enable_spi_indirect_access(dev);
+	if (ret < 0) {
+		dev_err(dev->dev, "failed to enable spi indirect access");
+		return ret;
+	}
 
 	/* The VLAN aware is a global setting. Mixed vlan
 	 * filterings are not supported.