GNU Linux-libre 4.14.266-gnu1
[releases.git] / Documentation / devicetree / bindings / net / mscc-phy-vsc8531.txt
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. Allowed values is listed
10                           in the first row of Table 1 (below).
11                           This property is only used in combination
12                           with the 'edge-slowdown' property.
13                           Default value is 3300.
14 - vsc8531,edge-slowdown : % the edge should be slowed down relative to
15                           the fastest possible edge time.
16                           Edge rate sets the drive strength of the MAC
17                           interface output signals.  Changing the
18                           drive strength will affect the edge rate of
19                           the output signal.  The goal of this setting
20                           is to help reduce electrical emission (EMI)
21                           by being able to reprogram drive strength
22                           and in effect slow down the edge rate if
23                           desired.
24                           To adjust the edge-slowdown, the 'vddmac'
25                           must be specified. Table 1 lists the
26                           supported edge-slowdown values for a given
27                           'vddmac'.
28                           Default value is 0%.
29                           Ref: Table:1 - Edge rate change (below).
30 - vsc8531,led-0-mode    : LED mode. Specify how the LED[0] should behave.
31                           Allowed values are define in
32                           "include/dt-bindings/net/mscc-phy-vsc8531.h".
33                           Default value is VSC8531_LINK_1000_ACTIVITY (1).
34 - vsc8531,led-1-mode    : LED mode. Specify how the LED[1] should behave.
35                           Allowed values are define in
36                           "include/dt-bindings/net/mscc-phy-vsc8531.h".
37                           Default value is VSC8531_LINK_100_ACTIVITY (2).
38
39 Table: 1 - Edge rate change
40 ----------------------------------------------------------------|
41 |               Edge Rate Change (VDDMAC)                       |
42 |                                                               |
43 | 3300 mV       2500 mV         1800 mV         1500 mV         |
44 |---------------------------------------------------------------|
45 | 0%            0%              0%              0%              |
46 | (Fastest)                     (recommended)   (recommended)   |
47 |---------------------------------------------------------------|
48 | 2%            3%              5%              6%              |
49 |---------------------------------------------------------------|
50 | 4%            6%              9%              14%             |
51 |---------------------------------------------------------------|
52 | 7%            10%             16%             21%             |
53 |(recommended)  (recommended)                                   |
54 |---------------------------------------------------------------|
55 | 10%           14%             23%             29%             |
56 |---------------------------------------------------------------|
57 | 17%           23%             35%             42%             |
58 |---------------------------------------------------------------|
59 | 29%           37%             52%             58%             |
60 |---------------------------------------------------------------|
61 | 53%           63%             76%             77%             |
62 | (slowest)                                                     |
63 |---------------------------------------------------------------|
64
65 Example:
66
67         vsc8531_0: ethernet-phy@0 {
68                 compatible = "ethernet-phy-id0007.0570";
69                 vsc8531,vddmac          = <3300>;
70                 vsc8531,edge-slowdown   = <7>;
71                 vsc8531,led-0-mode      = <LINK_1000_ACTIVITY>;
72                 vsc8531,led-1-mode      = <LINK_100_ACTIVITY>;
73         };