diff --git a/src/devtools/met-driver/4.9/common/sampler.h b/src/devtools/met-driver/4.9/common/sampler.h
new file mode 100644
index 0000000..6089c2d
--- /dev/null
+++ b/src/devtools/met-driver/4.9/common/sampler.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2018 MediaTek Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _SAMPLER_H_
+#define _SAMPLER_H_
+
+/*
+ * sampling rate: 1ms
+ * log generating rate: 10ms
+ */
+#if 0
+#define DEFAULT_TIMER_EXPIRE (HZ / 100)
+#define DEFAULT_HRTIMER_EXPIRE (TICK_NSEC / 10)
+#else
+extern int met_timer_expire;	/* in jiffies */
+extern int met_hrtimer_expire;	/* in us */
+#define DEFAULT_TIMER_EXPIRE (met_timer_expire)
+#define DEFAULT_HRTIMER_EXPIRE (met_hrtimer_expire)
+#endif
+/*
+ * sampling rate: 10ms
+ * log generating rate: 100ms
+ */
+/* #define DEFAULT_TIMER_EXPIRE (HZ / 10) */
+/* #define DEFAULT_HRTIMER_EXPIRE (TICK_NSEC / 1) */
+
+int met_hrtimer_start(void);
+void met_hrtimer_stop(void);
+int sampler_start(void);
+void sampler_stop(void);
+
+extern struct list_head met_list;
+extern void add_cookie(struct pt_regs *regs, int cpu);
+extern int met_hrtimer_suspend(void);
+extern void met_hrtimer_resume(void);
+extern void met_event_timer_notify(void);
+
+#ifdef CONFIG_CPU_FREQ
+#include "power.h"
+#endif
+
+#endif				/* _SAMPLER_H_ */