diff --git a/ch9344.c b/ch9344.c
index a16af82..8922ed9 100644
--- a/ch9344.c
+++ b/ch9344.c
@@ -774,7 +774,7 @@ static inline void *tty_get_portdata(struct ch9344_ttyport *port)
     return (port->portdata);
 }
 
-static void ch9344_port_dtr_rts(struct tty_port *port, int raise)
+static void ch9344_port_dtr_rts(struct tty_port *port, bool raise)
 {
     struct ch9344_ttyport *ttyport = container_of(port, struct ch9344_ttyport, port);
     struct ch9344 *ch9344 = tty_get_portdata(ttyport);