Subject: Re: [v3,net-next] net: phy: Add Edge-rate driver for Microsemi PHYs.

From: Andrew Lunn <[email-masked]>
Date: Tue, 27 Sep 2016 23:14:36 +0200

I just realised the possibly correct binding was starring me in the
face.

--------------------------------------------------------------|
|  3.3V	 	2.5V  		1.8V  		1.5V          |
|-------------------------------------------------------------|
|-2%		-3%		-5%		-6%           |
|-------------------------------------------------------------|
|-4%		-6%		-9%		-14%          |
|-------------------------------------------------------------|
|-7%		-10%		-16%		-21%          |
|-------------------------------------------------------------|
|-10%		-14%		-23%		-29%          |
|-------------------------------------------------------------|
|-17%		-23%		-35%		-42%          |
|-------------------------------------------------------------|
|-29%		-37%		-52%		-58%          |
|-------------------------------------------------------------|
|-53%		-63%		-76%		-77%          |
|-------------------------------------------------------------|

So the binding is:

vsc8531,vddmac		: The vddmac in mV.
vsc8531,edge-slowdown	: % the edge should be slowed down relative to
                          the fastest possible edge time.

Given those two values, the driver can work out the magic value to put
into the register that nobody knows the true meaning of.

     Andrew