base-modem: allow retrieving non-connected data ports

Bearers will ask for data ports that can be used for connections. Right now,
only one data port is expected to be handled, but we don't impose any
restriction in the API.

src/mm-base-modem.c

@@ -302,9 +302,6 @@ mm_base_modem_grab_port (MMBaseModem *self,
         if (!self->priv->data || MM_IS_AT_SERIAL_PORT (self->priv->data)) {
             g_clear_object (&self->priv->data);
             self->priv->data = g_object_ref (port);
-
-            /* TODO: */
-            /* check_valid (self); */
         }
 
         mm_dbg ("(%s/%s) port grabbed by %s",
@@ -420,6 +417,19 @@ mm_base_modem_get_port_qcdm (MMBaseModem *self)
     return self->priv->qcdm;
 }
 
+MMPort *
+mm_base_modem_get_best_data_port (MMBaseModem *self)
+{
+    g_return_val_if_fail (MM_IS_BASE_MODEM (self), NULL);
+
+    /* TODO: sometime we'll have a list of available data ports to use instead
+     * of a single one */
+
+    return (mm_port_get_connected (self->priv->data) ?
+            NULL :
+            self->priv->data);
+}
+
 gboolean
 mm_base_modem_auth_request (MMBaseModem *self,
                             const gchar *authorization,

src/mm-base-modem.h

@@ -107,6 +107,7 @@ gboolean  mm_base_modem_owns_port    (MMBaseModem *self,
 MMAtSerialPort   *mm_base_modem_get_port_primary   (MMBaseModem *self);
 MMAtSerialPort   *mm_base_modem_get_port_secondary (MMBaseModem *self);
 MMQcdmSerialPort *mm_base_modem_get_port_qcdm      (MMBaseModem *self);
+MMPort           *mm_base_modem_get_best_data_port (MMBaseModem *self);
 
 void     mm_base_modem_set_valid    (MMBaseModem *self,
                                      gboolean valid);