Add overall_mutex() method to check for flag

Author: CleoQc

i2c_mutex.py

@@ -1,5 +1,6 @@
 import fcntl
 import time
+import os
 
 class Mutex(object):
 
@@ -41,6 +42,13 @@ def enableDebug(self):
     def disableDebug(self):
         self.mutex_debug = False
 
+    def overall_mutex(self):
+        if os.path.isfile("/run/DexterOS_overall_mutex"):
+            return True
+        else:
+            return False
+
+
     def __enter__(self):
         if self.mutex_debug:
             print("I2C mutex enter")