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, 4 insertions, 2 deletions

diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index 013efffd2e82..d0a021c93986 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -250,16 +250,18 @@ err_reset_data:
 	return ERR_PTR(ret);
 }
 
-void serdev_tty_port_unregister(struct tty_port *port)
+int serdev_tty_port_unregister(struct tty_port *port)
 {
 	struct serdev_controller *ctrl = port->client_data;
 	struct serport *serport = serdev_controller_get_drvdata(ctrl);
 
 	if (!serport)
-		return;
+		return -ENODEV;
 
 	serdev_controller_remove(ctrl);
 	port->client_ops = NULL;
 	port->client_data = NULL;
 	serdev_controller_put(ctrl);
+
+	return 0;
 }