• Raju Lakkaraju's avatar
    net: phy: Add Edge-rate driver for Microsemi PHYs. · a4cc96d1
    Raju Lakkaraju authored
    Edge-rate:
    As system and networking speeds increase, a signal's output transition,
    also know as the edge rate or slew rate (V/ns), takes on greater importance
    because high-speed signals come with a price. That price is an assortment of
    interference problems like ringing on the line, signal overshoot and
    undershoot, extended signal settling times, crosstalk noise, transmission
    line reflections, false signal detection by the receiving device and
    electromagnetic interference (EMI) -- all of which can negate the potential
    gains designers are seeking when they try to increase system speeds through
    the use of higher performance logic devices. The fact is, faster signaling
    edge rates can cause a higher level of electrical noise or other type of
    interference that can actually lead to slower line speeds and lower maximum
    system frequencies. This parameter allow the board designers to change the
    driving strange, and thereby change the EMI behavioral.
    
    Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
    
    Tested on Beaglebone Black with VSC 8531 PHY.
    Signed-off-by: default avatarRaju Lakkaraju <Raju.Lakkaraju@microsemi.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a4cc96d1
mscc-phy-vsc8531.h 492 Bytes