[PATCH net-next v3 2/3] net: ethtool: Add impedance mismatch result code to cable test

[Pawel Dembicki <paweldembicki@gmail.com>]

Some PHYs can recognize during a cable test if the impedance in the cable
is okay. They can detect reflections caused by impedance discontinuity
between a regular 100 Ohm cable and an abnormal part with a higher or
lower impedance.

This commit introduces a new result code:
ETHTOOL_A_CABLE_RESULT_CODE_IMPEDANCE_MISMATCH,
which represents the results of a cable test indicating issues with
impedance integrity.

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
---
v3:
  - added enum description
  - improve commit message
v2:
  - introduce patch

 include/uapi/linux/ethtool_netlink.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 3f89074aa06c..accbb1a231df 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -515,6 +515,10 @@ enum {
 	ETHTOOL_A_CABLE_RESULT_CODE_OPEN,
 	ETHTOOL_A_CABLE_RESULT_CODE_SAME_SHORT,
 	ETHTOOL_A_CABLE_RESULT_CODE_CROSS_SHORT,
+	/* detected reflection caused by the impedance discontinuity between
+	 * a regular 100 Ohm cable and a part with the abnormal impedance value
+	 */
+	ETHTOOL_A_CABLE_RESULT_CODE_IMPEDANCE_MISMATCH,
 };
 
 enum {
-- 
2.25.1