greybus: Greybus driver: add a new callbacks to driver

Add connection_create and connection_destroy callbacks.

ES2 can map a cport to a pair of endpoints.
Because ES2 have only a few pair of endpoints, ES2 need to have
access to some high level connection information such as protocol id
to effectively map the cports.
These callback will provide these information and help ES2 to map cports.
Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/connection.c

@@ -262,6 +262,8 @@ gb_connection_create_range(struct greybus_host_device *hd,
 		gb_svc_connection_create(hd->svc,
 					 hd->endo->ap_intf_id, hd_cport_id,
 					 bundle->intf->interface_id, cport_id);
+		if (hd->driver->connection_create)
+			hd->driver->connection_create(connection);
 	}
 
 	gb_connection_bind_protocol(connection);
@@ -430,6 +432,9 @@ void gb_connection_destroy(struct gb_connection *connection)
 	list_del(&connection->hd_links);
 	spin_unlock_irq(&gb_connections_lock);
 
+	if (connection->hd->driver->connection_destroy)
+		connection->hd->driver->connection_destroy(connection);
+
 	if (connection->protocol)
 		gb_protocol_put(connection->protocol);
 	connection->protocol = NULL;

drivers/staging/greybus/greybus.h

@@ -75,6 +75,8 @@ struct greybus_host_device;
 struct greybus_host_driver {
 	size_t	hd_priv_size;
 
+	void (*connection_create)(struct gb_connection *connection);
+	void (*connection_destroy)(struct gb_connection *connection);
 	int (*message_send)(struct greybus_host_device *hd, u16 dest_cport_id,
 			struct gb_message *message, gfp_t gfp_mask);
 	void (*message_cancel)(struct gb_message *message);