timekeeping: Provide ktime_mono_to_any()

ktime based conversion function to map a monotonic time stamp to a
different CLOCK.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 3050a7d..910a98e 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -109,6 +109,7 @@
 extern ktime_t ktime_get(void);
 extern ktime_t ktime_get_with_offset(enum tk_offsets offs);
 extern ktime_t ktime_get_monotonic_offset(void);
+extern ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs);
 
 /**
  * ktime_get_real - get the real (wall-) time in ktime_t format
@@ -137,6 +138,14 @@
 	return ktime_get_with_offset(TK_OFFS_TAI);
 }
 
+/**
+ * ktime_mono_to_real - Convert monotonic time to clock realtime
+ */
+static inline ktime_t ktime_mono_to_real(ktime_t mono)
+{
+	return ktime_mono_to_any(mono, TK_OFFS_REAL);
+}
+
 /*
  * RTC specific
  */