--- dahdi-linux-complete-3.1.0+3.1.0/linux/include/dahdi/kernel.h	2019-10-03 21:48:09.000000000 +0700
+++ dahdi-linux-complete/linux/include/dahdi/kernel.h	2020-05-18 18:44:35.942817272 +0700
@@ -1388,23 +1397,27 @@
 #define TIMER_DATA_TYPE struct timer_list *
 #endif
 #endif
+#endif /* 4.13.0 */
 
 #ifndef DAHDI_HAVE_TIMER_SETUP
 /**
  * timer_setup - Added in 4.13.0.  We can make a direct translation to the
  * setup_timer interface since DAHDI does not pass any flags to any of the
  * timer_setup functions.
+ * Callback syntax changed in 4.15.0, but we use it's syntax in our "timer_setup".
+ * So, we have to provide our "timer_setup" till 4.15.0 .
  *
  */
 static inline void
-timer_setup(struct timer_list *timer,
+fake_timer_setup(struct timer_list *timer,
 	    void (*timer_callback)(TIMER_DATA_TYPE data),
 	    unsigned long flags)
 {
 	WARN_ON(flags != 0);
 	setup_timer(timer, timer_callback, (TIMER_DATA_TYPE)timer);
 }
-
+#define timer_setup fake_timer_setup
+#undef from_timer
 #define from_timer(var, callback_timer, timer_fieldname) \
 	container_of((struct timer_list *)(callback_timer), \
 		     typeof(*var), timer_fieldname)
@@ -1482,7 +1495,6 @@
 #endif /* 4.0.0 */
 #endif /* 4.10.0 */
 #endif /* 4.11.0 */
-#endif /* 4.13.0 */
 #else /* >= 4.15.0 */
 
 #ifndef TIMER_DATA_TYPE