Fixed link Device Tree binding
------------------------------
Some Ethernet MACs have a "fixed link", and are not connected to a
normal MDIO-managed PHY device. For those situations, a Device Tree
binding allows to describe a "fixed link".
Note there are two ways to describe a fixed PHY attached to an
Ethernet device:
- The new DT binding, where 'fixed-link' is a sub-node of the Ethernet
MAC device node, with the following properties:
* 'speed' (integer, mandatory), to indicate the link speed. Accepted
values are 10, 100 and 1000
* 'full-duplex' (boolean, optional), to indicate that full duplex is
used. When absent, half duplex is assumed.
* 'pause' (boolean, optional), to indicate that pause should be
enabled.
* 'asym-pause' (boolean, optional), to indicate that asym_pause should
be enabled.
- The old DT binding, where 'fixed-link' is a property with 5 cells
encoding various information about the fixed PHY, in the form of
<phy_id, full-duplex, speed, pause, asym-pause>.
* 'phy_id', emulated PHY ID, choose any but unique to the all specified
fixed-links. Note U-Boot deliberately ignores the 'phy_id' and
unconditionally uses PHY_FIXED_ID.
* 'full-duplex', 0 for half duplex or 1 for full duplex
* 'speed', link speed in Mbits/sec, accepts only 10, 100 and 1000
* 'pause', 0 for no pause, 1 for pause
* 'asym-pause', 0 for no asymmetric pause, 1 for asymmetric pause
Examples:
The new binding:
ethernet@0 {
...
fixed-link {
speed = <1000>;
full-duplex;
};
...
};
The old binding:
ethernet@0 {
...
fixed-link = <0 1 1000 0 0>;
...
};