diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
index 2f3f28c7cea3..9373662cdb44 100644
--- a/include/acpi/actypes.h
+++ b/include/acpi/actypes.h
@@ -532,11 +532,12 @@ typedef u64 acpi_integer;
 	 strnlen (a, ACPI_NAMESEG_SIZE) == ACPI_NAMESEG_SIZE)
 
 /*
- * Algorithm to obtain access bit width.
+ * Algorithm to obtain access bit or byte width.
  * Can be used with access_width of struct acpi_generic_address and access_size of
  * struct acpi_resource_generic_register.
  */
 #define ACPI_ACCESS_BIT_WIDTH(size)     (1 << ((size) + 2))
+#define ACPI_ACCESS_BYTE_WIDTH(size)    (1 << ((size) - 1))
 
 /*******************************************************************************
  *