diff --git a/src/uu/cksum/src/cksum.rs b/src/uu/cksum/src/cksum.rs
index 146fe0d56..d86c44819 100644
--- a/src/uu/cksum/src/cksum.rs
+++ b/src/uu/cksum/src/cksum.rs
@@ -52,6 +52,12 @@ struct Options {
     output_bits: usize,
 }
 
+/// Calculate checksum
+///
+/// # Arguments
+///
+/// * `options` - CLI options for the assigning checksum algorithm
+/// * `files` - A iterator of OsStr which is a bunch of files that are using for calculating checksum
 #[allow(clippy::cognitive_complexity)]
 fn cksum<'a, I>(mut options: Options, files: I) -> UResult<()>
 where