diff --git a/drivers/i2c/busses/i2c-at91-slave.c b/drivers/i2c/busses/i2c-at91-slave.c
index d6eeea5166c0..131a67d9d4a6 100644
--- a/drivers/i2c/busses/i2c-at91-slave.c
+++ b/drivers/i2c/busses/i2c-at91-slave.c
@@ -106,8 +106,7 @@ static int at91_unreg_slave(struct i2c_client *slave)
 
 static u32 at91_twi_func(struct i2c_adapter *adapter)
 {
-	return I2C_FUNC_SLAVE | I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
-		| I2C_FUNC_SMBUS_READ_BLOCK_DATA;
+	return I2C_FUNC_SLAVE;
 }
 
 static const struct i2c_algorithm at91_twi_algorithm_slave = {
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 2e079cf20bb5..78e2c47e3d7d 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -220,7 +220,7 @@ static const struct i2c_algorithm i2c_dw_algo = {
 
 void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
 {
-	dev->functionality = I2C_FUNC_SLAVE | DW_IC_DEFAULT_FUNCTIONALITY;
+	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;