diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index 17affdecbe30..53d9337db5e2 100644
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -359,21 +359,25 @@ static inline u32 i2c_dw_acpi_round_bus_speed(struct device *device) { return 0;
 
 #endif	/* CONFIG_ACPI */
 
-static void i2c_dw_configure_mode(struct dw_i2c_dev *dev)
+static void i2c_dw_configure_mode(struct dw_i2c_dev *dev, int mode)
 {
-	switch (dev->mode) {
+	switch (mode) {
 	case DW_IC_MASTER:
 		regmap_write(dev->map, DW_IC_TX_TL, dev->tx_fifo_depth / 2);
 		regmap_write(dev->map, DW_IC_RX_TL, 0);
 		regmap_write(dev->map, DW_IC_CON, dev->master_cfg);
 		break;
 	case DW_IC_SLAVE:
+		dev->status = 0;
 		regmap_write(dev->map, DW_IC_TX_TL, 0);
 		regmap_write(dev->map, DW_IC_RX_TL, 0);
 		regmap_write(dev->map, DW_IC_CON, dev->slave_cfg);
+		regmap_write(dev->map, DW_IC_SAR, dev->slave->addr);
 		regmap_write(dev->map, DW_IC_INTR_MASK, DW_IC_INTR_SLAVE_MASK);
+		__i2c_dw_enable(dev);
 		break;
 	default:
+		WARN(1, "Invalid mode %d\n", mode);
 		return;
 	}
 }
@@ -395,6 +399,31 @@ static void i2c_dw_write_timings(struct dw_i2c_dev *dev)
 	}
 }
 
+/**
+ * i2c_dw_set_mode() - Select the controller mode of operation - master or slave
+ * @dev: device private data
+ * @mode: I2C mode of operation
+ *
+ * Configures the controller to operate in @mode. This function needs to be
+ * called when ever a mode swap is required.
+ *
+ * Setting the slave mode does not have an effect before a slave device is
+ * registered. So before the slave device is registered, the controller is kept
+ * in master mode regardless of @mode.
+ *
+ * The controller must be disabled before this function is called.
+ */
+void i2c_dw_set_mode(struct dw_i2c_dev *dev, int mode)
+{
+	if (mode == DW_IC_SLAVE && !dev->slave)
+		mode = DW_IC_MASTER;
+	if (dev->mode == mode)
+		return;
+
+	i2c_dw_configure_mode(dev, mode);
+	dev->mode = mode;
+}
+
 /**
  * i2c_dw_init() - Initialize the DesignWare I2C hardware
  * @dev: device private data
@@ -421,14 +450,13 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	 */
 	regmap_write(dev->map, DW_IC_SMBUS_INTR_MASK, 0);
 
-	if (dev->mode == DW_IC_MASTER)
-		i2c_dw_write_timings(dev);
+	i2c_dw_write_timings(dev);
 
 	/* Write SDA hold time if supported */
 	if (dev->sda_hold_time)
 		regmap_write(dev->map, DW_IC_SDA_HOLD, dev->sda_hold_time);
 
-	i2c_dw_configure_mode(dev);
+	i2c_dw_configure_mode(dev, dev->mode);
 
 	i2c_dw_release_lock(dev);
 
@@ -864,17 +892,7 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
 	if (ret)
 		return ret;
 
-	switch (dev->mode) {
-	case DW_IC_SLAVE:
-		ret = i2c_dw_probe_slave(dev);
-		break;
-	case DW_IC_MASTER:
-		ret = i2c_dw_probe_master(dev);
-		break;
-	default:
-		ret = -EINVAL;
-		break;
-	}
+	ret = i2c_dw_probe_master(dev);
 	if (ret)
 		return ret;
 
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 63a59bb03163..a49263a36023 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -398,26 +398,23 @@ int i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
 
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 extern void i2c_dw_configure_slave(struct dw_i2c_dev *dev);
-extern int i2c_dw_probe_slave(struct dw_i2c_dev *dev);
 irqreturn_t i2c_dw_isr_slave(struct dw_i2c_dev *dev);
 int i2c_dw_reg_slave(struct i2c_client *client);
 int i2c_dw_unreg_slave(struct i2c_client *client);
 #else
 static inline void i2c_dw_configure_slave(struct dw_i2c_dev *dev) { }
-static inline int i2c_dw_probe_slave(struct dw_i2c_dev *dev) { return -EINVAL; }
 static inline irqreturn_t i2c_dw_isr_slave(struct dw_i2c_dev *dev) { return IRQ_NONE; }
 #endif
 
 static inline void i2c_dw_configure(struct dw_i2c_dev *dev)
 {
-	if (i2c_detect_slave_mode(dev->dev))
-		i2c_dw_configure_slave(dev);
-	else
-		i2c_dw_configure_master(dev);
+	i2c_dw_configure_slave(dev);
+	i2c_dw_configure_master(dev);
 }
 
 int i2c_dw_probe(struct dw_i2c_dev *dev);
 int i2c_dw_init(struct dw_i2c_dev *dev);
+void i2c_dw_set_mode(struct dw_i2c_dev *dev, int mode);
 
 #if IS_ENABLED(CONFIG_I2C_DESIGNWARE_BAYTRAIL)
 int i2c_dw_baytrail_probe_lock_support(struct dw_i2c_dev *dev);
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index 22c1bb463c2c..8ca254cbb2f8 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -194,6 +194,8 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 	/* Disable the adapter */
 	__i2c_dw_disable(dev);
 
+	i2c_dw_set_mode(dev, DW_IC_MASTER);
+
 	/* If the slave address is ten bit address, enable 10BITADDR */
 	if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) {
 		ic_con = DW_IC_CON_10BITADDR_MASTER;
@@ -831,6 +833,8 @@ i2c_dw_xfer_common(struct dw_i2c_dev *dev, struct i2c_msg msgs[], int num)
 	ret = -EIO;
 
 done:
+	i2c_dw_set_mode(dev, DW_IC_SLAVE);
+
 	i2c_dw_release_lock(dev);
 
 done_nolock:
@@ -853,7 +857,7 @@ void i2c_dw_configure_master(struct dw_i2c_dev *dev)
 {
 	struct i2c_timings *t = &dev->timings;
 
-	dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY;
+	dev->functionality |= I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY;
 
 	dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
 			  DW_IC_CON_RESTART_EN;
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 9fc8faa33735..ad0d5fbfa6d5 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -24,24 +24,25 @@
 int i2c_dw_reg_slave(struct i2c_client *slave)
 {
 	struct dw_i2c_dev *dev = i2c_get_adapdata(slave->adapter);
+	int ret;
 
+	if (!i2c_check_functionality(slave->adapter, I2C_FUNC_SLAVE))
+		return -EOPNOTSUPP;
 	if (dev->slave)
 		return -EBUSY;
 	if (slave->flags & I2C_CLIENT_TEN)
 		return -EAFNOSUPPORT;
+
+	ret = i2c_dw_acquire_lock(dev);
+	if (ret)
+		return ret;
+
 	pm_runtime_get_sync(dev->dev);
-
-	/*
-	 * Set slave address in the IC_SAR register,
-	 * the address to which the DW_apb_i2c responds.
-	 */
 	__i2c_dw_disable_nowait(dev);
-	regmap_write(dev->map, DW_IC_SAR, slave->addr);
 	dev->slave = slave;
+	i2c_dw_set_mode(dev, DW_IC_SLAVE);
 
-	__i2c_dw_enable(dev);
-
-	dev->status = 0;
+	i2c_dw_release_lock(dev);
 
 	return 0;
 }
@@ -54,6 +55,7 @@ int i2c_dw_unreg_slave(struct i2c_client *slave)
 	i2c_dw_disable(dev);
 	synchronize_irq(dev->irq);
 	dev->slave = NULL;
+	i2c_dw_set_mode(dev, DW_IC_MASTER);
 	pm_runtime_put_sync_suspend(dev->dev);
 
 	return 0;
@@ -176,23 +178,16 @@ irqreturn_t i2c_dw_isr_slave(struct dw_i2c_dev *dev)
 
 void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
 {
-	dev->functionality = I2C_FUNC_SLAVE;
+	if (dev->flags & ACCESS_POLLING)
+		return;
+
+	dev->functionality |= I2C_FUNC_SLAVE;
 
 	dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL |
 			 DW_IC_CON_RESTART_EN | DW_IC_CON_STOP_DET_IFADDRESSED;
-
-	dev->mode = DW_IC_SLAVE;
 }
 EXPORT_SYMBOL_GPL(i2c_dw_configure_slave);
 
-int i2c_dw_probe_slave(struct dw_i2c_dev *dev)
-{
-	if (dev->flags & ACCESS_POLLING)
-		return -EOPNOTSUPP;
-
-	return 0;
-}
-
 MODULE_AUTHOR("Luis Oliveira <lolivei@synopsys.com>");
 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus slave adapter");
 MODULE_LICENSE("GPL v2");