diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 2f3789515445..6e80d7bd3c4d 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -1231,9 +1231,9 @@ static void capinc_tty_hangup(struct tty_struct *tty)
 	tty_port_hangup(&mp->port);
 }
 
-static void capinc_tty_send_xchar(struct tty_struct *tty, char ch)
+static void capinc_tty_send_xchar(struct tty_struct *tty, u8 ch)
 {
-	pr_debug("capinc_tty_send_xchar(%d)\n", ch);
+	pr_debug("capinc_tty_send_xchar(%u)\n", ch);
 }
 
 static const struct tty_operations capinc_ops = {
diff --git a/drivers/mmc/core/sdio_uart.c b/drivers/mmc/core/sdio_uart.c
index a05322f15771..370fadf1d6d1 100644
--- a/drivers/mmc/core/sdio_uart.c
+++ b/drivers/mmc/core/sdio_uart.c
@@ -792,7 +792,7 @@ static unsigned int sdio_uart_chars_in_buffer(struct tty_struct *tty)
 	return kfifo_len(&port->xmit_fifo);
 }
 
-static void sdio_uart_send_xchar(struct tty_struct *tty, char ch)
+static void sdio_uart_send_xchar(struct tty_struct *tty, u8 ch)
 {
 	struct sdio_uart_port *port = tty->driver_data;
 
diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index a80f059f77bf..a30dc054ffbf 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -811,7 +811,7 @@ static void rs_flush_buffer(struct tty_struct *tty)
  * This function is used to send a high-priority XON/XOFF character to
  * the device
  */
-static void rs_send_xchar(struct tty_struct *tty, char ch)
+static void rs_send_xchar(struct tty_struct *tty, u8 ch)
 {
 	struct serial_state *info = tty->driver_data;
         unsigned long flags;
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 0393853b9947..80085b151b34 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -687,7 +687,7 @@ EXPORT_SYMBOL_GPL(uart_xchar_out);
  * This function is used to send a high-priority XON/XOFF character to
  * the device
  */
-static void uart_send_xchar(struct tty_struct *tty, char ch)
+static void uart_send_xchar(struct tty_struct *tty, u8 ch)
 {
 	struct uart_state *state = tty->driver_data;
 	struct uart_port *port;
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 005d91c63707..6a502110da61 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1149,7 +1149,7 @@ ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter)
  *
  * Locking: none for xchar method, write ordering for write method.
  */
-int tty_send_xchar(struct tty_struct *tty, char ch)
+int tty_send_xchar(struct tty_struct *tty, u8 ch)
 {
 	bool was_stopped = tty->flow.stopped;
 
diff --git a/include/linux/tty.h b/include/linux/tty.h
index e96c85f4f91e..d3bedcc08738 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -410,7 +410,7 @@ void tty_wait_until_sent(struct tty_struct *tty, long timeout);
 void stop_tty(struct tty_struct *tty);
 void start_tty(struct tty_struct *tty);
 void tty_write_message(struct tty_struct *tty, char *msg);
-int tty_send_xchar(struct tty_struct *tty, char ch);
+int tty_send_xchar(struct tty_struct *tty, u8 ch);
 int tty_put_char(struct tty_struct *tty, unsigned char c);
 unsigned int tty_chars_in_buffer(struct tty_struct *tty);
 unsigned int tty_write_room(struct tty_struct *tty);
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index f428c1b784a2..7372124fbf90 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -242,7 +242,7 @@ struct serial_struct;
  *	Optional: If not provided, the device is assumed to have no FIFO.
  *	Usually correct to invoke via tty_wait_until_sent(). May sleep.
  *
- * @send_xchar: ``void ()(struct tty_struct *tty, char ch)``
+ * @send_xchar: ``void ()(struct tty_struct *tty, u8 ch)``
  *
  *	This routine is used to send a high-priority XON/XOFF character (@ch)
  *	to the @tty device.
@@ -374,7 +374,7 @@ struct tty_operations {
 	void (*flush_buffer)(struct tty_struct *tty);
 	void (*set_ldisc)(struct tty_struct *tty);
 	void (*wait_until_sent)(struct tty_struct *tty, int timeout);
-	void (*send_xchar)(struct tty_struct *tty, char ch);
+	void (*send_xchar)(struct tty_struct *tty, u8 ch);
 	int (*tiocmget)(struct tty_struct *tty);
 	int (*tiocmset)(struct tty_struct *tty,
 			unsigned int set, unsigned int clear);
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index 94ec913dfb76..69c75c041fe1 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -1041,7 +1041,7 @@ static void rfcomm_tty_flush_buffer(struct tty_struct *tty)
 	tty_wakeup(tty);
 }
 
-static void rfcomm_tty_send_xchar(struct tty_struct *tty, char ch)
+static void rfcomm_tty_send_xchar(struct tty_struct *tty, u8 ch)
 {
 	BT_DBG("tty %p ch %c", tty, ch);
 }