diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 8f99d36..8d18313 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -326,9 +326,10 @@ struct nand_hw_control {
  * @read_page_raw:	function to read a raw page without ECC
  * @write_page_raw:	function to write a raw page without ECC
  * @read_page:	function to read a page according to the ECC generator
- *		requirements.
+ *		requirements.  Returns maximum number of bitflips corrected in
+ *		any single ecc step, 0 if bitflips uncorrectible, -EIO hw error.
  * @read_subpage:	function to read parts of the page covered by ECC.
+ *			Returns same as read_page().
  * @write_page:	function to write a page according to the ECC generator
  *		requirements.
  * @write_oob_raw:	function to write chip OOB data without ECC
--