diff --git a/sys/compat/linuxkpi/common/include/linux/delay.h b/sys/compat/linuxkpi/common/include/linux/delay.h
--- a/sys/compat/linuxkpi/common/include/linux/delay.h
+++ b/sys/compat/linuxkpi/common/include/linux/delay.h
@@ -76,4 +76,14 @@
 
 extern unsigned int linux_msleep_interruptible(unsigned int ms);
 
+static inline void
+fsleep(unsigned long us)
+{
+
+	if (us < 10)
+		udelay(us);
+	else
+		usleep_range(us, us);
+}
+
 #endif	/* _LINUX_DELAY_H_ */