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Diffstat (limited to 'Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt')
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diff --git a/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt b/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt new file mode 100644 index 000000000000..99c7eb0a00c8 --- /dev/null +++ b/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt @@ -0,0 +1,58 @@ +* Microsemi - vsc8531 Giga bit ethernet phy + +Required properties: +- compatible : Should contain phy id as "ethernet-phy-idAAAA.BBBB" + The PHY device uses the binding described in + Documentation/devicetree/bindings/net/phy.txt + +Optional properties: +- vsc8531,vddmac : The vddmac in mV. +- vsc8531,edge-slowdown : % the edge should be slowed down relative to + the fastest possible edge time. Native sign + need not enter. + 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 + +Table: 1 - Edge rate change +----------------------------------------------------------------| +| Edge Rate Change (VDDMAC) | +| | +| 3300 mV 2500 mV 1800 mV 1500 mV | +|---------------------------------------------------------------| +| Default Deafult Default Default | +| (Fastest) (recommended) (recommended) | +|---------------------------------------------------------------| +| -2% -3% -5% -6% | +|---------------------------------------------------------------| +| -4% -6% -9% -14% | +|---------------------------------------------------------------| +| -7% -10% -16% -21% | +|(recommended) (recommended) | +|---------------------------------------------------------------| +| -10% -14% -23% -29% | +|---------------------------------------------------------------| +| -17% -23% -35% -42% | +|---------------------------------------------------------------| +| -29% -37% -52% -58% | +|---------------------------------------------------------------| +| -53% -63% -76% -77% | +| (slowest) | +|---------------------------------------------------------------| + +Example: + + vsc8531_0: ethernet-phy@0 { + compatible = "ethernet-phy-id0007.0570"; + vsc8531,vddmac = <3300>; + vsc8531,edge-slowdown = <21>; + }; |