1Fixed link Device Tree binding
2------------------------------
3
4Some Ethernet MACs have a "fixed link", and are not connected to a
5normal MDIO-managed PHY device. For those situations, a Device Tree
6binding allows to describe a "fixed link".
7
8Note there are two ways to describe a fixed PHY attached to an
9Ethernet device:
10
11- The new DT binding, where 'fixed-link' is a sub-node of the Ethernet
12  MAC device node, with the following properties:
13
14  * 'speed' (integer, mandatory), to indicate the link speed. Accepted
15    values are 10, 100 and 1000
16  * 'full-duplex' (boolean, optional), to indicate that full duplex is
17    used. When absent, half duplex is assumed.
18  * 'pause' (boolean, optional), to indicate that pause should be
19    enabled.
20  * 'asym-pause' (boolean, optional), to indicate that asym_pause should
21    be enabled.
22
23- The old DT binding, where 'fixed-link' is a property with 5 cells
24  encoding various information about the fixed PHY, in the form of
25  <phy_id, full-duplex, speed, pause, asym-pause>.
26
27  * 'phy_id', emulated PHY ID, choose any but unique to the all specified
28    fixed-links. Note U-Boot deliberately ignores the 'phy_id' and
29    unconditionally uses PHY_FIXED_ID.
30  * 'full-duplex', 0 for half duplex or 1 for full duplex
31  * 'speed', link speed in Mbits/sec, accepts only 10, 100 and 1000
32  * 'pause', 0 for no pause, 1 for pause
33  * 'asym-pause', 0 for no asymmetric pause, 1 for asymmetric pause
34
35Examples:
36
37The new binding:
38
39ethernet@0 {
40	...
41	fixed-link {
42	      speed = <1000>;
43	      full-duplex;
44	};
45	...
46};
47
48The old binding:
49
50ethernet@0 {
51	...
52	fixed-link = <0 1 1000 0 0>;
53	...
54};
55