net: phy: Cleanup the Edge-Rate feature in Microsemi PHYs.

Edge-Rate cleanup include the following:
- Updated device tree bindings documentation for edge-rate
- The edge-rate is now specified as a "slowdown", meaning that it is now
  being specified as positive values instead of negative (both
  documentation and implementation wise).
- Only explicitly documented values for "vsc8531,vddmac" and
  "vsc8531,edge-slowdown" are accepted by the device driver.
- Deleted include/dt-bindings/net/mscc-phy-vsc8531.h as it was not needed.
- Read/validate devicetree settings in probe instead of init

Signed-off-by: Allan W. Nielsen <allan.nielsen@microsemi.com>
Signed-off-by: Raju Lakkaraju <raju.lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 23 deletions

diff --git a/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt b/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt
index 99c7eb0a00c8..bdefefc66594 100644
--- a/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt
+++ b/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt
@@ -6,22 +6,27 @@ Required properties:
 		  Documentation/devicetree/bindings/net/phy.txt
 
 Optional properties:
-- vsc8531,vddmac	: The vddmac in mV.
+- vsc8531,vddmac	: The vddmac in mV. Allowed values is listed
+			  in the first row of Table 1 (below).
+			  This property is only used in combination
+			  with the 'edge-slowdown' property.
+			  Default value is 3300.
 - vsc8531,edge-slowdown	: % the edge should be slowed down relative to
-			  the fastest possible edge time. Native sign
-			  need not enter.
+			  the fastest possible edge time.
 			  Edge rate sets the drive strength of the MAC
-			  interface output signals.  Changing the drive
-			  strength will affect the edge rate of the output
-			  signal.  The goal of this setting is to help
-			  reduce electrical emission (EMI) by being able
-			  to reprogram drive strength and in effect slow
-			  down the edge rate if desired.  Table 1 shows the
-			  impact to the edge rate per VDDMAC supply for each
-			  drive strength setting.
-			  Ref: Table:1 - Edge rate change below.
-
-Note: see dt-bindings/net/mscc-phy-vsc8531.h for applicable values
+			  interface output signals.  Changing the
+			  drive strength will affect the edge rate of
+			  the output signal.  The goal of this setting
+			  is to help reduce electrical emission (EMI)
+			  by being able to reprogram drive strength
+			  and in effect slow down the edge rate if
+			  desired.
+			  To adjust the edge-slowdown, the 'vddmac'
+			  must be specified. Table 1 lists the
+			  supported edge-slowdown values for a given
+			  'vddmac'.
+			  Default value is 0%.
+			  Ref: Table:1 - Edge rate change (below).
 
 Table: 1 - Edge rate change
 ----------------------------------------------------------------|
@@ -29,23 +34,23 @@ Table: 1 - Edge rate change
 |								|
 | 3300 mV	2500 mV		1800 mV		1500 mV		|
 |---------------------------------------------------------------|
-| Default	Deafult		Default		Default		|
+| 0%		0%		0%		0%		|
 | (Fastest)			(recommended)	(recommended)	|
 |---------------------------------------------------------------|
-| -2%		-3%		-5%		-6%		|
+| 2%		3%		5%		6%		|
 |---------------------------------------------------------------|
-| -4%		-6%		-9%		-14%		|
+| 4%		6%		9%		14%		|
 |---------------------------------------------------------------|
-| -7%		-10%		-16%		-21%		|
+| 7%		10%		16%		21%		|
 |(recommended)	(recommended)					|
 |---------------------------------------------------------------|
-| -10%		-14%		-23%		-29%		|
+| 10%		14%		23%		29%		|
 |---------------------------------------------------------------|
-| -17%		-23%		-35%		-42%		|
+| 17%		23%		35%		42%		|
 |---------------------------------------------------------------|
-| -29%		-37%		-52%		-58%		|
+| 29%		37%		52%		58%		|
 |---------------------------------------------------------------|
-| -53%		-63%		-76%		-77%		|
+| 53%		63%		76%		77%		|
 | (slowest)							|
 |---------------------------------------------------------------|
 
@@ -54,5 +59,5 @@ Example:
         vsc8531_0: ethernet-phy@0 {
                 compatible = "ethernet-phy-id0007.0570";
                 vsc8531,vddmac		= <3300>;
-                vsc8531,edge-slowdown	= <21>;
+                vsc8531,edge-slowdown	= <7>;
         };