diff -pNaru5 perle-serial-3.9.2.orig-0005/pserial/perle-serial.c perle-serial-3.9.2/pserial/perle-serial.c
--- perle-serial-3.9.2.orig-0005/pserial/perle-serial.c	2021-09-14 11:28:43.064657062 -0400
+++ perle-serial-3.9.2/pserial/perle-serial.c	2021-09-14 11:31:16.193566625 -0400
@@ -947,10 +947,14 @@ static _INLINE_ void receive_chars(struc
 #else
 	tty_flip_buffer_push(tty);
 #endif
 }
 
+#if (LINUX_VERSION_CODE >=  KERNEL_VERSION(5,14,0))
+#define stopped flow.stopped /* tty->stopped */
+#endif
+
 static _INLINE_ void transmit_chars(struct ps_async_struct *info, int *intr_done)
 {
 	int count;
 
 	/* echo suppression logic */
@@ -2195,20 +2199,28 @@ static int ps_write(struct tty_struct *
 }
 #endif		// > 2.6.10
 
 
 
+#if (LINUX_VERSION_CODE >=  KERNEL_VERSION(5,14,0))
+static unsigned int ps_write_room(struct tty_struct *tty)
+#else
 static int ps_write_room(struct tty_struct *tty)
+#endif
 {
 	struct ps_async_struct *info = (struct ps_async_struct *)tty->driver_data;
 
 	if (ps_paranoia_check(info, tty, "ps_write_room"))
 		return 0;
 	return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 }
 
+#if (LINUX_VERSION_CODE >=  KERNEL_VERSION(5,14,0))
+static unsigned int ps_chars_in_buffer(struct tty_struct *tty)
+#else
 static int ps_chars_in_buffer(struct tty_struct *tty)
+#endif
 {
 	struct ps_async_struct *info = (struct ps_async_struct *)tty->driver_data;
 				
 	if (ps_paranoia_check(info, tty, "ps_chars_in_buffer"))
 		return 0;