ethtool: Expand documentation of struct ethtool_regs

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 3 deletions

diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 15a42de87fec..441bd316b850 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -209,11 +209,25 @@ struct ethtool_value {
         __u32   data;
 };
 
-/* for passing big chunks of data */
+/**
+ * struct ethtool_regs - hardware register dump
+ * @cmd: Command number = %ETHTOOL_GREGS
+ * @version: Dump format version.  This is driver-specific and may
+ *      distinguish different chips/revisions.  Drivers must use new
+ *      version numbers whenever the dump format changes in an
+ *      incompatible way.
+ * @len: On entry, the real length of @data.  On return, the number of
+ *      bytes used.
+ * @data: Buffer for the register dump
+ *
+ * Users should use %ETHTOOL_GDRVINFO to find the maximum length of
+ * a register dump for the interface.  They must allocate the buffer
+ * immediately following this structure.
+ */
 struct ethtool_regs {
         __u32   cmd;
-        __u32   version; /* driver-specific, indicates different chips/revs */
-        __u32   len; /* bytes */
+        __u32   version;
+        __u32   len;
         __u8    data[0];
 };