Raju Lakkaraju | a4cc96d | 2016-10-03 12:53:13 +0530 | [diff] [blame] | 1 | * Microsemi - vsc8531 Giga bit ethernet phy |
| 2 | |
| 3 | Required properties: |
| 4 | - compatible : Should contain phy id as "ethernet-phy-idAAAA.BBBB" |
| 5 | The PHY device uses the binding described in |
| 6 | Documentation/devicetree/bindings/net/phy.txt |
| 7 | |
| 8 | Optional properties: |
| 9 | - vsc8531,vddmac : The vddmac in mV. |
| 10 | - vsc8531,edge-slowdown : % the edge should be slowed down relative to |
| 11 | the fastest possible edge time. Native sign |
| 12 | need not enter. |
| 13 | Edge rate sets the drive strength of the MAC |
| 14 | interface output signals. Changing the drive |
| 15 | strength will affect the edge rate of the output |
| 16 | signal. The goal of this setting is to help |
| 17 | reduce electrical emission (EMI) by being able |
| 18 | to reprogram drive strength and in effect slow |
| 19 | down the edge rate if desired. Table 1 shows the |
| 20 | impact to the edge rate per VDDMAC supply for each |
| 21 | drive strength setting. |
| 22 | Ref: Table:1 - Edge rate change below. |
| 23 | |
| 24 | Note: see dt-bindings/net/mscc-phy-vsc8531.h for applicable values |
| 25 | |
| 26 | Table: 1 - Edge rate change |
| 27 | ----------------------------------------------------------------| |
| 28 | | Edge Rate Change (VDDMAC) | |
| 29 | | | |
| 30 | | 3300 mV 2500 mV 1800 mV 1500 mV | |
| 31 | |---------------------------------------------------------------| |
| 32 | | Default Deafult Default Default | |
| 33 | | (Fastest) (recommended) (recommended) | |
| 34 | |---------------------------------------------------------------| |
| 35 | | -2% -3% -5% -6% | |
| 36 | |---------------------------------------------------------------| |
| 37 | | -4% -6% -9% -14% | |
| 38 | |---------------------------------------------------------------| |
| 39 | | -7% -10% -16% -21% | |
| 40 | |(recommended) (recommended) | |
| 41 | |---------------------------------------------------------------| |
| 42 | | -10% -14% -23% -29% | |
| 43 | |---------------------------------------------------------------| |
| 44 | | -17% -23% -35% -42% | |
| 45 | |---------------------------------------------------------------| |
| 46 | | -29% -37% -52% -58% | |
| 47 | |---------------------------------------------------------------| |
| 48 | | -53% -63% -76% -77% | |
| 49 | | (slowest) | |
| 50 | |---------------------------------------------------------------| |
| 51 | |
| 52 | Example: |
| 53 | |
| 54 | vsc8531_0: ethernet-phy@0 { |
| 55 | compatible = "ethernet-phy-id0007.0570"; |
| 56 | vsc8531,vddmac = <3300>; |
| 57 | vsc8531,edge-slowdown = <21>; |
| 58 | }; |