serdev: add a tty port controller driver

Add a serdev controller driver for tty ports.

The controller is registered with serdev when tty ports are registered
with the TTY core. As the TTY core is built-in only, this has the side
effect of making serdev built-in as well.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-By: Sebastian Reichel <sre@kernel.org>
Tested-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 3ac26c1a8aab..9519da6253a8 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -238,4 +238,25 @@ static inline int serdev_device_write_room(struct serdev_device *sdev)
 
 #endif /* CONFIG_SERIAL_DEV_BUS */
 
+/*
+ * serdev hooks into TTY core
+ */
+struct tty_port;
+struct tty_driver;
+
+#ifdef CONFIG_SERIAL_DEV_CTRL_TTYPORT
+struct device *serdev_tty_port_register(struct tty_port *port,
+                                        struct device *parent,
+                                        struct tty_driver *drv, int idx);
+void serdev_tty_port_unregister(struct tty_port *port);
+#else
+static inline struct device *serdev_tty_port_register(struct tty_port *port,
+                                           struct device *parent,
+                                           struct tty_driver *drv, int idx)
+{
+        return ERR_PTR(-ENODEV);
+}
+static inline void serdev_tty_port_unregister(struct tty_port *port) {}
+#endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
+
 #endif /*_LINUX_SERDEV_H */