diff --git a/arch/arm/src/stm32/stm32_serial.c b/arch/arm/src/stm32/stm32_serial.c
index 9afe350cce4..286ca54b856 100644
--- a/arch/arm/src/stm32/stm32_serial.c
+++ b/arch/arm/src/stm32/stm32_serial.c
@@ -1965,7 +1965,9 @@ static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
 #else
         if ((arg & SER_SINGLEWIRE_ENABLED) != 0)
           {
-            uint32_t gpio_val = (arg & SER_SINGLEWIRE_PULLUP) ? GPIO_PULLUP : GPIO_OPENDRAIN;
+            uint32_t gpio_val = GPIO_OPENDRAIN;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLUP ? GPIO_PULLUP : GPIO_FLOAT;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLDOWN ? GPIO_PULLDOWN : GPIO_FLOAT;
             stm32_configgpio((priv->tx_gpio & ~(GPIO_PUPD_MASK | GPIO_OPENDRAIN)) | gpio_val);
             cr |= USART_CR3_HDSEL;
           }
diff --git a/arch/arm/src/stm32f0l0g0/stm32_serial_v1.c b/arch/arm/src/stm32f0l0g0/stm32_serial_v1.c
index 44801cad12a..a7fb7dedb62 100644
--- a/arch/arm/src/stm32f0l0g0/stm32_serial_v1.c
+++ b/arch/arm/src/stm32f0l0g0/stm32_serial_v1.c
@@ -1604,7 +1604,9 @@ static int stm32serial_ioctl(FAR struct file *filep, int cmd,
 
         if ((arg & SER_SINGLEWIRE_ENABLED) != 0)
           {
-            uint32_t gpio_val = (arg & SER_SINGLEWIRE_PULLUP) ? GPIO_PULLUP : GPIO_OPENDRAIN;
+            uint32_t gpio_val = GPIO_OPENDRAIN;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLUP ? GPIO_PULLUP : GPIO_FLOAT;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLDOWN ? GPIO_PULLDOWN : GPIO_FLOAT;
             stm32_configgpio((priv->tx_gpio & ~(GPIO_PUPD_MASK | GPIO_OPENDRAIN)) | gpio_val);
             cr |= USART_CR3_HDSEL;
           }
diff --git a/arch/arm/src/stm32f0l0g0/stm32_serial_v2.c b/arch/arm/src/stm32f0l0g0/stm32_serial_v2.c
index 8abaf03163a..c4ebab329bb 100644
--- a/arch/arm/src/stm32f0l0g0/stm32_serial_v2.c
+++ b/arch/arm/src/stm32f0l0g0/stm32_serial_v2.c
@@ -1163,7 +1163,9 @@ static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
 
         if ((arg & SER_SINGLEWIRE_ENABLED) != 0)
           {
-            uint32_t gpio_val = (arg & SER_SINGLEWIRE_PULLUP) ? GPIO_PULLUP : GPIO_OPENDRAIN;
+            uint32_t gpio_val = GPIO_OPENDRAIN;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLUP ? GPIO_PULLUP : GPIO_FLOAT;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLDOWN ? GPIO_PULLDOWN : GPIO_FLOAT;
             stm32_configgpio((priv->tx_gpio & ~(GPIO_PUPD_MASK | GPIO_OPENDRAIN)) | gpio_val);
             cr |= USART_CR3_HDSEL;
           }
diff --git a/arch/arm/src/stm32f7/stm32_serial.c b/arch/arm/src/stm32f7/stm32_serial.c
index dbf2dac63b6..dd80234ca21 100644
--- a/arch/arm/src/stm32f7/stm32_serial.c
+++ b/arch/arm/src/stm32f7/stm32_serial.c
@@ -2127,7 +2127,9 @@ static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
 
         if ((arg & SER_SINGLEWIRE_ENABLED) != 0)
           {
-            uint32_t gpio_val = (arg & SER_SINGLEWIRE_PULLUP) ? GPIO_PULLUP : GPIO_OPENDRAIN;
+            uint32_t gpio_val = GPIO_OPENDRAIN;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLUP ? GPIO_PULLUP : GPIO_FLOAT;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLDOWN ? GPIO_PULLDOWN : GPIO_FLOAT;
             stm32_configgpio((priv->tx_gpio & ~(GPIO_PUPD_MASK | GPIO_OPENDRAIN)) | gpio_val);
             cr |= USART_CR3_HDSEL;
           }
diff --git a/arch/arm/src/stm32h7/stm32_serial.c b/arch/arm/src/stm32h7/stm32_serial.c
index f8bff1724cd..04e07845427 100644
--- a/arch/arm/src/stm32h7/stm32_serial.c
+++ b/arch/arm/src/stm32h7/stm32_serial.c
@@ -1532,7 +1532,9 @@ static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
 
         if ((arg & SER_SINGLEWIRE_ENABLED) != 0)
           {
-            uint32_t gpio_val = (arg & SER_SINGLEWIRE_PULLUP) ? GPIO_PULLUP : GPIO_OPENDRAIN;
+            uint32_t gpio_val = GPIO_OPENDRAIN;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLUP ? GPIO_PULLUP : GPIO_FLOAT;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLDOWN ? GPIO_PULLDOWN : GPIO_FLOAT;
             stm32_configgpio((priv->tx_gpio & ~(GPIO_PUPD_MASK | GPIO_OPENDRAIN)) | gpio_val);
             cr |= USART_CR3_HDSEL;
           }
diff --git a/arch/arm/src/stm32l4/stm32l4_serial.c b/arch/arm/src/stm32l4/stm32l4_serial.c
index cc9a4d12ee9..3c77043c40c 100644
--- a/arch/arm/src/stm32l4/stm32l4_serial.c
+++ b/arch/arm/src/stm32l4/stm32l4_serial.c
@@ -1825,7 +1825,9 @@ static int stm32l4serial_ioctl(FAR struct file *filep, int cmd,
 
         if ((arg & SER_SINGLEWIRE_ENABLED) != 0)
           {
-            uint32_t gpio_val = (arg & SER_SINGLEWIRE_PULLUP) ? GPIO_PULLUP : GPIO_OPENDRAIN;
+            uint32_t gpio_val = GPIO_OPENDRAIN;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLUP ? GPIO_PULLUP : GPIO_FLOAT;
+            gpio_val |= (arg & SER_SINGLEWIRE_PULL_MASK) == SER_SINGLEWIRE_PULLDOWN ? GPIO_PULLDOWN : GPIO_FLOAT;
             stm32l4_configgpio((priv->tx_gpio & ~(GPIO_PUPD_MASK | GPIO_OPENDRAIN)) | gpio_val);
             cr |= USART_CR3_HDSEL;
           }
diff --git a/include/nuttx/serial/tioctl.h b/include/nuttx/serial/tioctl.h
index e8dd02d3072..9ce789256ca 100644
--- a/include/nuttx/serial/tioctl.h
+++ b/include/nuttx/serial/tioctl.h
@@ -184,8 +184,12 @@
 #define TIOCSSINGLEWIRE _TIOC(0x0030)  /* Set single-wire mode */
 #define TIOCGSINGLEWIRE _TIOC(0x0031)  /* Get single-wire mode */
 
-#  define SER_SINGLEWIRE_ENABLED   (1 << 0) /* Enable/disable single-wire support */
-#  define SER_SINGLEWIRE_PULLUP    (1 << 1) /* Enable Pull-up on TX (Open-Drain otherwise) */
+#  define SER_SINGLEWIRE_ENABLED      (1 << 0) /* Enable/disable single-wire support */
+#  define SER_SINGLEWIRE_PULL_SHIFT   (1)      /* RX/TX Line Pullup/down control */
+#  define SER_SINGLEWIRE_PULL_MASK    (3 << SER_SINGLEWIRE_PULL_SHIFT)
+#  define SER_SINGLEWIRE_PULL_DISABLE (0 << SER_SINGLEWIRE_PULL_SHIFT) /* Float RX/TX Line */
+#  define SER_SINGLEWIRE_PULLUP       (1 << SER_SINGLEWIRE_PULL_SHIFT) /* Enable Pull up the RX/TX Line */
+#  define SER_SINGLEWIRE_PULLDOWN     (2 << SER_SINGLEWIRE_PULL_SHIFT) /* Enable Pull down the RX/TX Line */
 
 /* Debugging */