Merge branch 'ethtool-implement-Energy-Detect-Powerdown-support-via-phy-tunable'

Alexandru Ardelean says:

====================
ethtool: implement Energy Detect Powerdown support via phy-tunable

This changeset proposes a new control for PHY tunable to control Energy
Detect Power Down.

The `phy_tunable_id` has been named `ETHTOOL_PHY_EDPD` since it looks like
this feature is common across other PHYs (like EEE), and defining
`ETHTOOL_PHY_ENERGY_DETECT_POWER_DOWN` seems too long.

The way EDPD works, is that the RX block is put to a lower power mode,
except for link-pulse detection circuits. The TX block is also put to low
power mode, but the PHY wakes-up periodically to send link pulses, to avoid
lock-ups in case the other side is also in EDPD mode.

Currently, there are 2 PHY drivers that look like they could use this new
PHY tunable feature: the `adin` && `micrel` PHYs.

This series updates only the `adin` PHY driver to support this new feature,
as this chip has been tested. A change for `micrel` can be proposed after a
discussion of the PHY-tunable API is resolved.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index dd06302aa93e..8938b76c4ee3 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -259,10 +259,32 @@ struct ethtool_tunable {
 #define ETHTOOL_PHY_FAST_LINK_DOWN_ON	0
 #define ETHTOOL_PHY_FAST_LINK_DOWN_OFF	0xff
 
+/* Energy Detect Power Down (EDPD) is a feature supported by some PHYs, where
+ * the PHY's RX & TX blocks are put into a low-power mode when there is no
+ * link detected (typically cable is un-plugged). For RX, only a minimal
+ * link-detection is available, and for TX the PHY wakes up to send link pulses
+ * to avoid any lock-ups in case the peer PHY may also be running in EDPD mode.
+ *
+ * Some PHYs may support configuration of the wake-up interval for TX pulses,
+ * and some PHYs may support only disabling TX pulses entirely. For the latter
+ * a special value is required (ETHTOOL_PHY_EDPD_NO_TX) so that this can be
+ * configured from userspace (should the user want it).
+ *
+ * The interval units for TX wake-up are in milliseconds, since this should
+ * cover a reasonable range of intervals:
+ *  - from 1 millisecond, which does not sound like much of a power-saver
+ *  - to ~65 seconds which is quite a lot to wait for a link to come up when
+ *    plugging a cable
+ */
+#define ETHTOOL_PHY_EDPD_DFLT_TX_MSECS		0xffff
+#define ETHTOOL_PHY_EDPD_NO_TX			0xfffe
+#define ETHTOOL_PHY_EDPD_DISABLE		0
+
 enum phy_tunable_id {
 	ETHTOOL_PHY_ID_UNSPEC,
 	ETHTOOL_PHY_DOWNSHIFT,
 	ETHTOOL_PHY_FAST_LINK_DOWN,
+	ETHTOOL_PHY_EDPD,
 	/*
 	 * Add your fresh new phy tunable attribute above and remember to update
 	 * phy_tunable_strings[] in net/core/ethtool.c