xref: /freebsd/sys/contrib/device-tree/Bindings/net/mscc-phy-vsc8531.txt (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e) 
1* Microsemi - vsc8531 Giga bit ethernet phy
2
3Optional properties:
4- vsc8531,vddmac	: The vddmac in mV. Allowed values is listed
5			  in the first row of Table 1 (below).
6			  This property is only used in combination
7			  with the 'edge-slowdown' property.
8			  Default value is 3300.
9- vsc8531,edge-slowdown	: % the edge should be slowed down relative to
10			  the fastest possible edge time.
11			  Edge rate sets the drive strength of the MAC
12			  interface output signals.  Changing the
13			  drive strength will affect the edge rate of
14			  the output signal.  The goal of this setting
15			  is to help reduce electrical emission (EMI)
16			  by being able to reprogram drive strength
17			  and in effect slow down the edge rate if
18			  desired.
19			  To adjust the edge-slowdown, the 'vddmac'
20			  must be specified. Table 1 lists the
21			  supported edge-slowdown values for a given
22			  'vddmac'.
23			  Default value is 0%.
24			  Ref: Table:1 - Edge rate change (below).
25- vsc8531,led-[N]-mode	: LED mode. Specify how the LED[N] should behave.
26			  N depends on the number of LEDs supported by a
27			  PHY.
28			  Allowed values are defined in
29			  "include/dt-bindings/net/mscc-phy-vsc8531.h".
30			  Default values are VSC8531_LINK_1000_ACTIVITY (1),
31			  VSC8531_LINK_100_ACTIVITY (2),
32			  VSC8531_LINK_ACTIVITY (0) and
33			  VSC8531_DUPLEX_COLLISION (8).
34- load-save-gpios	: GPIO used for the load/save operation of the PTP
35			  hardware clock (PHC).
36
37
38Table: 1 - Edge rate change
39----------------------------------------------------------------|
40| 		Edge Rate Change (VDDMAC)			|
41|								|
42| 3300 mV	2500 mV		1800 mV		1500 mV		|
43|---------------------------------------------------------------|
44| 0%		0%		0%		0%		|
45| (Fastest)			(recommended)	(recommended)	|
46|---------------------------------------------------------------|
47| 2%		3%		5%		6%		|
48|---------------------------------------------------------------|
49| 4%		6%		9%		14%		|
50|---------------------------------------------------------------|
51| 7%		10%		16%		21%		|
52|(recommended)	(recommended)					|
53|---------------------------------------------------------------|
54| 10%		14%		23%		29%		|
55|---------------------------------------------------------------|
56| 17%		23%		35%		42%		|
57|---------------------------------------------------------------|
58| 29%		37%		52%		58%		|
59|---------------------------------------------------------------|
60| 53%		63%		76%		77%		|
61| (slowest)							|
62|---------------------------------------------------------------|
63
64Example:
65
66        vsc8531_0: ethernet-phy@0 {
67                compatible = "ethernet-phy-id0007.0570";
68                vsc8531,vddmac		= <3300>;
69                vsc8531,edge-slowdown	= <7>;
70                vsc8531,led-0-mode	= <VSC8531_LINK_1000_ACTIVITY>;
71                vsc8531,led-1-mode	= <VSC8531_LINK_100_ACTIVITY>;
72		load-save-gpios		= <&gpio 10 GPIO_ACTIVE_HIGH>;
73        };
74