greybus: initial operations-based GPIO driver

First cut.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/connection.c

@@ -206,6 +206,7 @@ int gb_connection_init(struct gb_connection *connection)
 	case GREYBUS_PROTOCOL_CONTROL:
 	case GREYBUS_PROTOCOL_AP:
 	case GREYBUS_PROTOCOL_GPIO:
+		return gb_gpio_controller_init(connection);
 	case GREYBUS_PROTOCOL_UART:
 	case GREYBUS_PROTOCOL_HID:
 	case GREYBUS_PROTOCOL_VENDOR:

drivers/staging/greybus/greybus.h

@@ -265,6 +265,7 @@ void gb_deregister_cport_complete(u16 cport_id);
 extern const struct attribute_group *greybus_module_groups[];
 
 int gb_i2c_device_init(struct gb_connection *connection);
+int gb_gpio_controller_init(struct gb_connection *connection);
 
 int gb_tty_init(void);
 void gb_tty_exit(void);