Support LED triggers for tracking link state


Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>PHY Device support and infrastructure
└─>Support LED triggers for tracking link state
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Adds support for a set of LED trigger events per-PHY. Link
state change will trigger the events, for consumption by an
LED class driver. There are triggers for each link speed currently
supported by the PHY and also a one common "link" trigger as a
logical-or of all the link speed ones.
All these triggers are named according to the following pattern:
<mii bus id>:<phy>:<speed>

Where speed is in the form:
<Speed in megabits>Mbps OR <Speed in gigabits>Gbps OR link
for any speed known to the PHY.