tty/serdev: add serdev registration interface

Add a new interface for registering a serdev controller and clients, and
a helper function to deregister serdev devices (or a tty device) that
were previously registered using the new interface.

Once every driver currently using the tty_port_register_device() helpers
have been vetted and converted to use the new serdev registration
interface (at least for deregistration), we can move serdev registration
to the current helpers and get rid of the serdev-specific functions.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index e2a225bf716d..e69402d4a8ae 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -308,7 +308,7 @@ struct tty_driver;
 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);
+int serdev_tty_port_unregister(struct tty_port *port);
 #else
 static inline struct device *serdev_tty_port_register(struct tty_port *port,
                                            struct device *parent,
@@ -316,7 +316,10 @@ static inline struct device *serdev_tty_port_register(struct tty_port *port,
 {
         return ERR_PTR(-ENODEV);
 }
-static inline void serdev_tty_port_unregister(struct tty_port *port) {}
+static inline int serdev_tty_port_unregister(struct tty_port *port)
+{
+        return -ENODEV;
+}
 #endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
 
 #endif /*_LINUX_SERDEV_H */