tty_port: Add a port level carrier detect operation
This is the first step to generalising the various pieces of waiting logic
duplicated in all sorts of serial drivers.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index c8f8024..f54e40c 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -94,3 +94,20 @@
spin_unlock_irqrestore(&port->lock, flags);
}
EXPORT_SYMBOL(tty_port_tty_set);
+
+/**
+ * tty_port_carrier_raised - carrier raised check
+ * @port: tty port
+ *
+ * Wrapper for the carrier detect logic. For the moment this is used
+ * to hide some internal details. This will eventually become entirely
+ * internal to the tty port.
+ */
+
+int tty_port_carrier_raised(struct tty_port *port)
+{
+ if (port->ops->carrier_raised == NULL)
+ return 1;
+ return port->ops->carrier_raised(port);
+}
+EXPORT_SYMBOL(tty_port_carrier_raised);