//
//  SplitViewController.swift
//  SplitView
//
//  Created by phatblat on 9/4/14.
//  Copyright (c) 2014 phatblat. All rights reserved.
//

import UIKit

class SplitViewController: UISplitViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        delegate = self
    }

}

// MARK: - SplitViewControllerDelegate

extension SplitViewController: UISplitViewControllerDelegate {

    func splitViewControllerSupportedInterfaceOrientations(splitViewController: UISplitViewController) -> UIInterfaceOrientationMask {
        return .All
    }

}

//
//  SplitViewController.swift
//  SplitView
//
//  Created by phatblat on 9/4/14.
//  Copyright (c) 2014 phatblat. All rights reserved.
//

import UIKit

class SplitViewController: UISplitViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    }

}

--- 
+++ 
@@ -12,6 +12,17 @@
 
     override func viewDidLoad() {
         super.viewDidLoad()
+        delegate = self
     }
 
 }
+
+// MARK: - SplitViewControllerDelegate
+
+extension SplitViewController: UISplitViewControllerDelegate {
+
+    func splitViewControllerSupportedInterfaceOrientations(splitViewController: UISplitViewController) -> UIInterfaceOrientationMask {
+        return .All
+    }
+
+}
Allow portrait upside down orientation on phones
