On Tue, Oct 04, 2016 at 05:11:12PM +0530, Raju Lakkaraju wrote:
> From: Raju Lakkaraju <raju.lakkar...@microsemi.com>
>
> 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: Raju Lakkaraju <raju.lakkar...@microsemi.com>
>
> ---
> All the review comments updated and resending for review.
>
> Change set:
> v1:
> - Initial version of Edge-rate driver add by using IOCTL.
> v2:
> - Changed edge-rate parameter to Device Tree with magic number.
> v3:
> - Added Device Tree documentati0n and edge-rate parameter table.
> Added probe function initialize the vsc8531 private data structure.
> v4:
> - As per review comment, Device Tree parameters (vddmac, edge-slowdown)
> added.
> v5:
> - As per review comment, Device Tree Document parameters (vddmac,
> edge-slowdown) real numbers added. Table number changed from 5 to 1.
> v6:
> - As per review comment, Removed Device Tree header file. Removed MACROs
> and add ARRAYSIZE
But you ignored my request to make the table values positive, and to
enforce an exact match in the table.
NACK
Andrew
