1 files changed, 2 insertions, 0 deletions
diff --git a/extmod/virtpin.h b/extmod/virtpin.h
index 706affc19..591249e48 100644
--- a/extmod/virtpin.h
+++ b/extmod/virtpin.h
@@ -27,6 +27,7 @@
 #define MICROPY_INCLUDED_EXTMOD_VIRTPIN_H
 
 #include "py/obj.h"
+#include "py/proto.h"
 
 #define MP_PIN_READ   (1)
 #define MP_PIN_WRITE  (2)
@@ -35,6 +36,7 @@
 
 // Pin protocol
 typedef struct _mp_pin_p_t {
+    MP_PROTOCOL_HEAD
     mp_uint_t (*ioctl)(mp_obj_t obj, mp_uint_t request, uintptr_t arg, int *errcode);
 } mp_pin_p_t;