Patch 1/2: This is Edge rate control feature. 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.
Microsemi PHY have the provision to configure the edge rate. Edge-rate function program the right value based on Device Tree configuration. Tested on Beaglebone Black with VSC 8531 PHY. Patch 2/2: This is MAC interface feature. Microsemi PHY can support RGMII, RMII or GMII/MII interface between MAC and PHY. MAC-IF function program the right value based on Device tree configuration. Tested on Beaglebone Black with VSC 8531 PHY. Raju Lakkaraju (2): net: phy: Add Edge-rate driver for Microsemi PHYs. net: phy: Add MAC-IF driver for Microsemi PHYs. drivers/net/phy/mscc.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) -- 2.7.4
