diff --git a/sys/compat/linuxkpi/common/include/linux/bcd.h b/sys/compat/linuxkpi/common/include/linux/bcd.h
new file mode 100644
index 000000000000..57fcb4c6bd98
--- /dev/null
+++ b/sys/compat/linuxkpi/common/include/linux/bcd.h
@@ -0,0 +1,53 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Bjoern A. Zeeb
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef	_LINUXKPI_LINUX_BCD_H
+#define	_LINUXKPI_LINUX_BCD_H
+
+#include <sys/types.h>
+
+/*
+ * We could use libkern, but we need the argument truncating.
+ *
+ * This leaves us with a duplicate symbol with conflicting types
+ * so we cannot simply re-define as libkern.h gets included in
+ * too many places directly or indirectly.  This means for now
+ * drivers will have to be adjusted to call linuxkpi_bcd2bin().
+ */
+static inline uint8_t linuxkpi_bcd2bin(uint8_t x)
+{
+
+	return (x & 0x0f) + (x >> 4) * 10;
+}
+
+#if 0
+#define	bcd2bin(_x)	linuxkpi_bcd2bin(_x)
+#endif
+
+#endif	/* _LINUXKPI_LINUX_BCD_H */