diff --git a/Makefile b/Makefile
index 760129d..6b1324e 100644
--- a/Makefile
+++ b/Makefile
@@ -57,6 +57,9 @@ asm: $(ASMS) $(OBJECTS)
 	wc -l $(ASMS)
 	size $(OBJECTS)
 
+tidy:
+	@clang-tidy $(C_SOURCES) -- $(CFLAGS)
+
 format:
 	clang-format -i $(C_SOURCES) $(C_HEADERS)
 
diff --git a/ringbuf.c b/ringbuf.c
index 23adb94..9ea1a6d 100644
--- a/ringbuf.c
+++ b/ringbuf.c
@@ -40,9 +40,9 @@ rb_init(struct RingBuf *rb, rb_size_t capacity, ALLOC_T malloc_fn,
 }
 
 void
-rb_destroy(struct RingBuf *rb, void(free)())
+rb_destroy(struct RingBuf *rb, FREE_T free_fn)
 {
-  free(rb->buffer);
+  free_fn(rb->buffer);
 }
 
 void
diff --git a/ringbuf.h b/ringbuf.h
index efffe50..6d6d01f 100644
--- a/ringbuf.h
+++ b/ringbuf.h
@@ -12,6 +12,9 @@ typedef void *(*ALLOC_T)(rb_size_t);
 /** Signature of memcpy */
 typedef void *(*MEMCPY_T)(void *, const void *, rb_size_t);
 
+/** Signature of free */
+typedef void (*FREE_T)(void *);
+
 /**
  * @brief Ring buffer, also known as circular buffer.
  */
@@ -26,7 +29,7 @@ struct RingBuf {
 } __attribute__((packed));
 
 /*
- * Considerations: One hot encoding for the enum values 
+ * Considerations: One hot encoding for the enum values
  * (8 bit each with -fshort-enums)
  */