greybus: lights: Break light setup into two parts

This breaks the light setup routine into two parts, the first one
allocates all the necessary resources and the second on registers lights
to the required frameworks.

This is required to enable only TX on the connection, until we have
allocated all the resources, otherwise the request handler might get
called for partially initialized structures.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Rui Miguel Silva <rui.silva@linaro.org>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/light.c

@@ -983,6 +983,14 @@ static int gb_lights_light_config(struct gb_lights *glights, u8 id)
 			return ret;
 	}
 
+	return 0;
+}
+
+static int gb_lights_light_register(struct gb_light *light)
+{
+	int ret;
+	int i;
+
 	/*
 	 * Then, if everything went ok in getting configurations, we register
 	 * the classdev, flash classdev and v4l2 subsystem, if a flash device is
@@ -1089,7 +1097,7 @@ static int gb_lights_get_count(struct gb_lights *glights)
 	return 0;
 }
 
-static int gb_lights_setup(struct gb_lights *glights)
+static int gb_lights_create_all(struct gb_lights *glights)
 {
 	struct gb_connection *connection = glights->connection;
 	int ret;
@@ -1121,11 +1129,32 @@ static int gb_lights_setup(struct gb_lights *glights)
 	return ret;
 }
 
+static int gb_lights_register_all(struct gb_lights *glights)
+{
+	struct gb_connection *connection = glights->connection;
+	int ret = 0;
+	int i;
+
+	mutex_lock(&glights->lights_lock);
+	for (i = 0; i < glights->lights_count; i++) {
+		ret = gb_lights_light_register(&glights->lights[i]);
+		if (ret < 0) {
+			dev_err(&connection->bundle->dev,
+				"Fail to enable lights device\n");
+			break;
+		}
+	}
+
+	mutex_unlock(&glights->lights_lock);
+	return ret;
+}
+
 static int gb_lights_event_recv(u8 type, struct gb_operation *op)
 {
 	struct gb_connection *connection = op->connection;
 	struct device *dev = &connection->bundle->dev;
 	struct gb_lights *glights = connection->private;
+	struct gb_light *light;
 	struct gb_message *request;
 	struct gb_lights_event_request *payload;
 	int ret =  0;
@@ -1157,11 +1186,15 @@ static int gb_lights_event_recv(u8 type, struct gb_operation *op)
 	event = payload->event;
 
 	if (event & GB_LIGHTS_LIGHT_CONFIG) {
+		light = &glights->lights[light_id];
+
 		mutex_lock(&glights->lights_lock);
-		gb_lights_light_release(&glights->lights[light_id]);
+		gb_lights_light_release(light);
 		ret = gb_lights_light_config(glights, light_id);
+		if (!ret)
+			ret = gb_lights_light_register(light);
 		if (ret < 0)
-			gb_lights_light_release(&glights->lights[light_id]);
+			gb_lights_light_release(light);
 		mutex_unlock(&glights->lights_lock);
 	}
 
@@ -1186,7 +1219,12 @@ static int gb_lights_connection_init(struct gb_connection *connection)
 	 * Setup all the lights devices over this connection, if anything goes
 	 * wrong tear down all lights
 	 */
-	ret = gb_lights_setup(glights);
+	ret = gb_lights_create_all(glights);
+	if (ret < 0)
+		goto out;
+
+	/* Enable & register lights */
+	ret = gb_lights_register_all(glights);
 	if (ret < 0)
 		goto out;