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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 000000000..0a3647fe3 --- /dev/null +++ b/Documentation/devicetree/bindings/net/mscc-phy-vsc8531.txt @@ -0,0 +1,73 @@ +* Microsemi - vsc8531 Giga bit ethernet phy + +Optional properties: +- 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. + 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. + 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). +- vsc8531,led-[N]-mode : LED mode. Specify how the LED[N] should behave. + N depends on the number of LEDs supported by a + PHY. + Allowed values are defined in + "include/dt-bindings/net/mscc-phy-vsc8531.h". + Default values are VSC8531_LINK_1000_ACTIVITY (1), + VSC8531_LINK_100_ACTIVITY (2), + VSC8531_LINK_ACTIVITY (0) and + VSC8531_DUPLEX_COLLISION (8). +- load-save-gpios : GPIO used for the load/save operation of the PTP + hardware clock (PHC). + + +Table: 1 - Edge rate change +----------------------------------------------------------------| +| Edge Rate Change (VDDMAC) | +| | +| 3300 mV 2500 mV 1800 mV 1500 mV | +|---------------------------------------------------------------| +| 0% 0% 0% 0% | +| (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 = <7>; + vsc8531,led-0-mode = <VSC8531_LINK_1000_ACTIVITY>; + vsc8531,led-1-mode = <VSC8531_LINK_100_ACTIVITY>; + load-save-gpios = <&gpio 10 GPIO_ACTIVE_HIGH>; + }; |