diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index a1fef666c9b0..16b6f430dfd3 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -1021,8 +1021,7 @@ static unsigned int tty3215_write_room(struct tty_struct *tty)
/*
* String write routine for 3215 ttys
*/
-static int tty3215_write(struct tty_struct *tty,
- const unsigned char *buf, int count)
+static int tty3215_write(struct tty_struct *tty, const u8 *buf, int count)
{
handle_write(tty->driver_data, buf, count);
return count;diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c
index d9983550062d..123524bff734 100644
--- a/drivers/s390/char/con3270.c
+++ b/drivers/s390/char/con3270.c
@@ -1803,8 +1803,7 @@ static void tty3270_do_write(struct tty3270 *tp, struct tty_struct *tty,
/*
* String write routine for 3270 ttys
*/
-static int tty3270_write(struct tty_struct *tty,
- const unsigned char *buf, int count)
+static int tty3270_write(struct tty_struct *tty, const u8 *buf, int count)
{
struct tty3270 *tp;
diff --git a/drivers/s390/char/sclp_tty.c b/drivers/s390/char/sclp_tty.c
index 971fbb52740b..cc0f6a97124e 100644
--- a/drivers/s390/char/sclp_tty.c
+++ b/drivers/s390/char/sclp_tty.c
@@ -230,7 +230,7 @@ static int sclp_tty_write_string(const unsigned char *str, int count, int may_fa
* routine will return the number of characters actually accepted for writing.
*/
static int
-sclp_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
+sclp_tty_write(struct tty_struct *tty, const u8 *buf, int count)
{
if (sclp_tty_chars_count > 0) {
sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
index a32f34a1c6d2..44974d801c1e 100644
--- a/drivers/s390/char/sclp_vt220.c
+++ b/drivers/s390/char/sclp_vt220.c
@@ -463,7 +463,7 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
* number of characters actually accepted for writing.
*/
static int
-sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
+sclp_vt220_write(struct tty_struct *tty, const u8 *buf, int count)
{
return __sclp_vt220_write(buf, count, 1, 0, 1);
}