[PATCH v2] average: Clarify the restrictions

[Jui-Tse Huang]

There is several restrictions in the EWMA helper macro that the
developers should take care of, but the comment does not mentioned yet,
thus, this patch clarify the restrictions.

Signed-off-by: Jui-Tse Huang <juitse.huang@xxxxxxxxx>
---

Notes:
    v2: fix spelling and wording (Bruno Randolf)

 include/linux/average.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/average.h b/include/linux/average.h
index a1a8f09631ce..ff0953ba2820 100644
--- a/include/linux/average.h
+++ b/include/linux/average.h
@@ -13,6 +13,9 @@
  * precision and fall-off coefficient determined at compile-time
  * and built into the generated helper funtions.
  *
+ * This implementation supports up to 30 bits of precition, and only
+ * the API for fetching non-fractional part is provided for now.
+ *
  * The first argument to the macro is the name that will be used
  * for the struct and helper functions.
  *
-- 
2.34.1