diff --git a/drivers/net/dsa/sja1105/sja1105.h b/drivers/net/dsa/sja1105/sja1105.h
index d801fc204d19..4c40f2d51a54 100644
--- a/drivers/net/dsa/sja1105/sja1105.h
+++ b/drivers/net/dsa/sja1105/sja1105.h
@@ -36,6 +36,7 @@ struct sja1105_regs {
 	u64 port_control;
 	u64 rgu;
 	u64 config;
+	u64 sgmii;
 	u64 rmii_pll1;
 	u64 ptp_control;
 	u64 ptpclkval;
@@ -159,6 +160,7 @@ typedef enum {
 	XMII_MODE_MII		= 0,
 	XMII_MODE_RMII		= 1,
 	XMII_MODE_RGMII		= 2,
+	XMII_MODE_SGMII		= 3,
 } sja1105_phy_interface_t;
 
 typedef enum {
diff --git a/drivers/net/dsa/sja1105/sja1105_clocking.c b/drivers/net/dsa/sja1105/sja1105_clocking.c
index 9082e52b55e9..0fdc2d55fff6 100644
--- a/drivers/net/dsa/sja1105/sja1105_clocking.c
+++ b/drivers/net/dsa/sja1105/sja1105_clocking.c
@@ -660,6 +660,10 @@ int sja1105_clocking_setup_port(struct sja1105_private *priv, int port)
 	case XMII_MODE_RGMII:
 		rc = sja1105_rgmii_clocking_setup(priv, port, role);
 		break;
+	case XMII_MODE_SGMII:
+		/* Nothing to do in the CGU for SGMII */
+		rc = 0;
+		break;
 	default:
 		dev_err(dev, "Invalid interface mode specified: %d\n",
 			phy_mode);
diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index edf57ea07083..816125afceee 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -22,6 +22,7 @@
 #include <linux/if_ether.h>
 #include <linux/dsa/8021q.h>
 #include "sja1105.h"
+#include "sja1105_sgmii.h"
 #include "sja1105_tas.h"
 
 static void sja1105_hw_reset(struct gpio_desc *gpio, unsigned int pulse_len,
@@ -135,6 +136,21 @@ static int sja1105_init_mac_settings(struct sja1105_private *priv)
 	return 0;
 }
 
+static bool sja1105_supports_sgmii(struct sja1105_private *priv, int port)
+{
+	if (priv->info->part_no != SJA1105R_PART_NO &&
+	    priv->info->part_no != SJA1105S_PART_NO)
+		return false;
+
+	if (port != SJA1105_SGMII_PORT)
+		return false;
+
+	if (dsa_is_unused_port(priv->ds, port))
+		return false;
+
+	return true;
+}
+
 static int sja1105_init_mii_settings(struct sja1105_private *priv,
 				     struct sja1105_dt_port *ports)
 {
@@ -178,12 +194,24 @@ static int sja1105_init_mii_settings(struct sja1105_private *priv,
 		case PHY_INTERFACE_MODE_RGMII_TXID:
 			mii->xmii_mode[i] = XMII_MODE_RGMII;
 			break;
+		case PHY_INTERFACE_MODE_SGMII:
+			if (!sja1105_supports_sgmii(priv, i))
+				return -EINVAL;
+			mii->xmii_mode[i] = XMII_MODE_SGMII;
+			break;
 		default:
 			dev_err(dev, "Unsupported PHY mode %s!\n",
 				phy_modes(ports[i].phy_mode));
 		}
 
-		mii->phy_mac[i] = ports[i].role;
+		/* Even though the SerDes port is able to drive SGMII autoneg
+		 * like a PHY would, from the perspective of the XMII tables,
+		 * the SGMII port should always be put in MAC mode.
+		 */
+		if (ports[i].phy_mode == PHY_INTERFACE_MODE_SGMII)
+			mii->phy_mac[i] = XMII_MAC;
+		else
+			mii->phy_mac[i] = ports[i].role;
 	}
 	return 0;
 }
@@ -650,6 +678,70 @@ static int sja1105_parse_dt(struct sja1105_private *priv,
 	return rc;
 }
 
+static int sja1105_sgmii_read(struct sja1105_private *priv, int pcs_reg)
+{
+	const struct sja1105_regs *regs = priv->info->regs;
+	u32 val;
+	int rc;
+
+	rc = sja1105_xfer_u32(priv, SPI_READ, regs->sgmii + pcs_reg, &val,
+			      NULL);
+	if (rc < 0)
+		return rc;
+
+	return val;
+}
+
+static int sja1105_sgmii_write(struct sja1105_private *priv, int pcs_reg,
+			       u16 pcs_val)
+{
+	const struct sja1105_regs *regs = priv->info->regs;
+	u32 val = pcs_val;
+	int rc;
+
+	rc = sja1105_xfer_u32(priv, SPI_WRITE, regs->sgmii + pcs_reg, &val,
+			      NULL);
+	if (rc < 0)
+		return rc;
+
+	return val;
+}
+
+static void sja1105_sgmii_config(struct sja1105_private *priv, int port,
+				 int speed)
+{
+	int pcs_speed;
+
+	/* DIGITAL_CONTROL_1: Enable vendor-specific MMD1, allow the PHY to
+	 * stop the clock during LPI mode, make the MAC reconfigure
+	 * autonomously after PCS autoneg is done, flush the internal FIFOs.
+	 */
+	sja1105_sgmii_write(priv, 0x8000, SJA1105_DC1_EN_VSMMD1 |
+					  SJA1105_DC1_CLOCK_STOP_EN |
+					  SJA1105_DC1_MAC_AUTO_SW |
+					  SJA1105_DC1_INIT);
+	/* DIGITAL_CONTROL_2: No polarity inversion for TX and RX lanes */
+	sja1105_sgmii_write(priv, 0x80e1, SJA1105_DC2_TX_POL_INV_DISABLE);
+	/* AUTONEG_CONTROL: Use SGMII autoneg */
+	sja1105_sgmii_write(priv, 0x8001, SJA1105_AC_AUTONEG_MODE_SGMII);
+
+	switch (speed) {
+	case SPEED_1000:
+		pcs_speed = BMCR_SPEED1000;
+		break;
+	case SPEED_100:
+		pcs_speed = BMCR_SPEED100;
+		break;
+	case SPEED_10:
+		pcs_speed = BMCR_SPEED10;
+		break;
+	default:
+		dev_err(priv->ds->dev, "Invalid speed %d\n", speed);
+		return;
+	}
+	sja1105_sgmii_write(priv, MII_BMCR, pcs_speed | BMCR_FULLDPLX);
+}
+
 /* Convert link speed from SJA1105 to ethtool encoding */
 static int sja1105_speed[] = {
 	[SJA1105_SPEED_AUTO]		= SPEED_UNKNOWN,
@@ -707,8 +799,13 @@ static int sja1105_adjust_port_config(struct sja1105_private *priv, int port,
 	 * table, since this will be used for the clocking setup, and we no
 	 * longer need to store it in the static config (already told hardware
 	 * we want auto during upload phase).
+	 * Actually for the SGMII port, the MAC is fixed at 1 Gbps and
+	 * we need to configure the PCS only (if even that).
 	 */
-	mac[port].speed = speed;
+	if (sja1105_supports_sgmii(priv, port))
+		mac[port].speed = SJA1105_SPEED_1000MBPS;
+	else
+		mac[port].speed = speed;
 
 	/* Write to the dynamic reconfiguration tables */
 	rc = sja1105_dynamic_config_write(priv, BLK_IDX_MAC_CONFIG, port,
@@ -757,6 +854,8 @@ static bool sja1105_phy_mode_mismatch(struct sja1105_private *priv, int port,
 	case PHY_INTERFACE_MODE_RGMII_RXID:
 	case PHY_INTERFACE_MODE_RGMII_TXID:
 		return (phy_mode != XMII_MODE_RGMII);
+	case PHY_INTERFACE_MODE_SGMII:
+		return (phy_mode != XMII_MODE_SGMII);
 	default:
 		return true;
 	}
@@ -798,6 +897,9 @@ static void sja1105_mac_link_up(struct dsa_switch *ds, int port,
 
 	sja1105_adjust_port_config(priv, port, speed);
 
+	if (sja1105_supports_sgmii(priv, port))
+		sja1105_sgmii_config(priv, port, speed);
+
 	sja1105_inhibit_tx(priv, BIT(port), false);
 }
 
@@ -833,7 +935,8 @@ static void sja1105_phylink_validate(struct dsa_switch *ds, int port,
 	phylink_set(mask, 10baseT_Full);
 	phylink_set(mask, 100baseT_Full);
 	phylink_set(mask, 100baseT1_Full);
-	if (mii->xmii_mode[port] == XMII_MODE_RGMII)
+	if (mii->xmii_mode[port] == XMII_MODE_RGMII ||
+	    mii->xmii_mode[port] == XMII_MODE_SGMII)
 		phylink_set(mask, 1000baseT_Full);
 
 	bitmap_and(supported, supported, mask, __ETHTOOL_LINK_MODE_MASK_NBITS);
@@ -1367,6 +1470,7 @@ int sja1105_static_config_reload(struct sja1105_private *priv,
 	struct dsa_switch *ds = priv->ds;
 	s64 t1, t2, t3, t4;
 	s64 t12, t34;
+	u16 bmcr = 0;
 	int rc, i;
 	s64 now;
 
@@ -1384,6 +1488,9 @@ int sja1105_static_config_reload(struct sja1105_private *priv,
 		mac[i].speed = SJA1105_SPEED_AUTO;
 	}
 
+	if (sja1105_supports_sgmii(priv, SJA1105_SGMII_PORT))
+		bmcr = sja1105_sgmii_read(priv, MII_BMCR);
+
 	/* No PTP operations can run right now */
 	mutex_lock(&priv->ptp_data.lock);
 
@@ -1433,6 +1540,19 @@ int sja1105_static_config_reload(struct sja1105_private *priv,
 		if (rc < 0)
 			goto out;
 	}
+
+	if (sja1105_supports_sgmii(priv, SJA1105_SGMII_PORT)) {
+		int speed = SPEED_UNKNOWN;
+
+		if (bmcr & BMCR_SPEED1000)
+			speed = SPEED_1000;
+		else if (bmcr & BMCR_SPEED100)
+			speed = SPEED_100;
+		else if (bmcr & BMCR_SPEED10)
+			speed = SPEED_10;
+
+		sja1105_sgmii_config(priv, SJA1105_SGMII_PORT, speed);
+	}
 out:
 	mutex_unlock(&priv->mgmt_lock);
 
diff --git a/drivers/net/dsa/sja1105/sja1105_sgmii.h b/drivers/net/dsa/sja1105/sja1105_sgmii.h
new file mode 100644
index 000000000000..0517b5bcb36e
--- /dev/null
+++ b/drivers/net/dsa/sja1105/sja1105_sgmii.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/* Copyright 2020, NXP Semiconductors
+ */
+#ifndef _SJA1105_SGMII_H
+#define _SJA1105_SGMII_H
+
+#define SJA1105_SGMII_PORT		4
+
+/* DIGITAL_CONTROL_1 (address 1f8000h) */
+#define SJA1105_DC1			0x8000
+#define SJA1105_DC1_VS_RESET		BIT(15)
+#define SJA1105_DC1_REMOTE_LOOPBACK	BIT(14)
+#define SJA1105_DC1_EN_VSMMD1		BIT(13)
+#define SJA1105_DC1_POWER_SAVE		BIT(11)
+#define SJA1105_DC1_CLOCK_STOP_EN	BIT(10)
+#define SJA1105_DC1_MAC_AUTO_SW		BIT(9)
+#define SJA1105_DC1_INIT		BIT(8)
+#define SJA1105_DC1_TX_DISABLE		BIT(4)
+#define SJA1105_DC1_AUTONEG_TIMER_OVRR	BIT(3)
+#define SJA1105_DC1_BYP_POWERUP		BIT(1)
+#define SJA1105_DC1_PHY_MODE_CONTROL	BIT(0)
+
+/* DIGITAL_CONTROL_2 register (address 1f80E1h) */
+#define SJA1105_DC2			0x80e1
+#define SJA1105_DC2_TX_POL_INV_DISABLE	BIT(4)
+#define SJA1105_DC2_RX_POL_INV		BIT(0)
+
+/* DIGITAL_ERROR_CNT register (address 1f80E2h) */
+#define SJA1105_DEC			0x80e2
+#define SJA1105_DEC_ICG_EC_ENA		BIT(4)
+#define SJA1105_DEC_CLEAR_ON_READ	BIT(0)
+
+/* AUTONEG_CONTROL register (address 1f8001h) */
+#define SJA1105_AC			0x8001
+#define SJA1105_AC_MII_CONTROL		BIT(8)
+#define SJA1105_AC_SGMII_LINK		BIT(4)
+#define SJA1105_AC_PHY_MODE		BIT(3)
+#define SJA1105_AC_AUTONEG_MODE(x)	(((x) << 1) & GENMASK(2, 1))
+#define SJA1105_AC_AUTONEG_MODE_1000BASEX \
+	SJA1105_AC_AUTONEG_MODE(0)
+#define SJA1105_AC_AUTONEG_MODE_SGMII \
+	SJA1105_AC_AUTONEG_MODE(2)
+
+/* AUTONEG_INTR_STATUS register (address 1f8002h) */
+#define SJA1105_AIS			0x8002
+#define SJA1105_AIS_LINK_STATUS(x)	(!!((x) & BIT(4)))
+#define SJA1105_AIS_SPEED(x)		(((x) & GENMASK(3, 2)) >> 2)
+#define SJA1105_AIS_DUPLEX_MODE(x)	(!!((x) & BIT(1)))
+#define SJA1105_AIS_COMPLETE(x)		(!!((x) & BIT(0)))
+
+/* DEBUG_CONTROL register (address 1f8005h) */
+#define SJA1105_DC			0x8005
+#define SJA1105_DC_SUPPRESS_LOS		BIT(4)
+#define SJA1105_DC_RESTART_SYNC		BIT(0)
+
+#endif
diff --git a/drivers/net/dsa/sja1105/sja1105_spi.c b/drivers/net/dsa/sja1105/sja1105_spi.c
index 29b127f3bf9c..45da162ba268 100644
--- a/drivers/net/dsa/sja1105/sja1105_spi.c
+++ b/drivers/net/dsa/sja1105/sja1105_spi.c
@@ -474,6 +474,7 @@ static struct sja1105_regs sja1105pqrs_regs = {
 	/* UM10944.pdf, Table 86, ACU Register overview */
 	.pad_mii_tx = {0x100800, 0x100802, 0x100804, 0x100806, 0x100808},
 	.pad_mii_id = {0x100810, 0x100811, 0x100812, 0x100813, 0x100814},
+	.sgmii = 0x1F0000,
 	.rmii_pll1 = 0x10000A,
 	.cgu_idiv = {0x10000B, 0x10000C, 0x10000D, 0x10000E, 0x10000F},
 	.mac = {0x200, 0x202, 0x204, 0x206, 0x208},
