Cellular: fixed defect where SIM interface was closed too early causing crash with certain configurations.

Author: Teppo Järvelin

features/cellular/easy_cellular/CellularConnectionFSM.cpp

@@ -436,8 +436,6 @@ void CellularConnectionFSM::state_sim_pin()
             retry_state_or_fail();
             return;
         }
-        _cellularDevice->close_sim();
-        _sim = NULL;
         if (_plmn) {
             enter_to_state(STATE_MANUAL_REGISTERING_NETWORK);
         } else {
@@ -485,6 +483,8 @@ void CellularConnectionFSM::state_attaching()
 {
     _cellularDevice->set_timeout(TIMEOUT_CONNECT);
     if (_network->set_attach() == NSAPI_ERROR_OK) {
+        _cellularDevice->close_sim();
+        _sim = NULL;
         enter_to_state(STATE_ACTIVATING_PDP_CONTEXT);
     } else {
         retry_state_or_fail();

features/cellular/easy_cellular/CellularConnectionFSM.h

@@ -117,9 +117,9 @@ class CellularConnectionFSM
      */
     CellularDevice *get_device();
 
-    /** Get cellular sim interface. SIM interface is released after SIM is open and ready for use (moving from STATE_SIM_PIN to next state).
-     *  After SIM interface is closed this method will return NULL. SIM interface can be created again via CellularDevice
-     *  which you can get with the method get_device().
+    /** Get cellular sim interface. SIM interface is released when moving from STATE_ATTACHING_NETWORK to STATE_ACTIVATING_PDP_CONTEXT.
+     *  After SIM interface is closed this method will return NULL and any instances fetched via this method are invalid.
+     *  SIM interface can be created again via CellularDevice which you can get with the method get_device().
      *  @return sim interface, NULL on failure
      */
     CellularSIM *get_sim();