diff --git a/src/devtools/met-driver/4.4/common/util.c b/src/devtools/met-driver/4.4/common/util.c
new file mode 100644
index 0000000..051a3bd
--- /dev/null
+++ b/src/devtools/met-driver/4.4/common/util.c
@@ -0,0 +1,88 @@
+/*
+ * 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.
+ */
+
+#include "util.h"
+#include <linux/fs.h>
+#include <linux/kernel.h>
+/* #include <asm/uaccess.h> */
+#include <linux/uaccess.h>
+
+#ifdef FILELOG
+
+static char tmp[1000] = { 0 };
+
+ /*TODO*/
+/**
+ * open file
+ * @param name path to open
+ * @return file pointer
+ */
+struct file *open_file(const char *name)
+{
+	struct file *fp = NULL;
+
+	fp = filp_open(name, O_WRONLY | O_APPEND /*| O_TRUNC */  | O_CREAT, 0664);
+	if (unlikely(fp == NULL)) {
+		pr_debug(KERNEL_INFO "can not open result file");
+		return NULL;
+	}
+	return fp;
+}
+
+/**
+ * write to file
+ * @param fp file pointer
+ * @param format format string
+ * @param ... variable-length subsequent arguments
+ */
+void write_file(struct file *fp, const char *format, ...)
+{
+	va_list va;
+	mm_segment_t fs = get_fs();
+
+	va_start(va, format);
+	vsnprintf(tmp, sizeof(tmp), format, va);
+	set_fs(KERNEL_DS);
+	vfs_write(fp, tmp, strlen(tmp), &(fp->f_pos));
+	set_fs(fs);
+	va_end(va);
+}
+
+/**
+ * close file
+ * @param fp file pointer
+ * @return exit code
+ */
+int close_file(struct file *fp)
+{
+	if (likely(fp != NULL)) {
+		filp_close(fp, NULL);
+		fp = NULL;
+		return 0;
+	}
+	pr_debug("cannot close file pointer:%p\n", fp);
+	return -1;
+}
+
+void filelog(char *str)
+{
+	struct file *fp;
+
+	fp = open_file("/data/met.log");
+	if (fp != NULL) {
+		write_file(fp, "%s", str);
+		close_file(fp);
+	}
+}
+
+#endif				/* FILELOG */