1Micrel KSZ9021/KSZ9031 Gigabit Ethernet PHY
2
3Some boards require special tuning values, particularly when it comes to
4clock delays. You can specify clock delay values by adding
5micrel-specific properties to an Ethernet OF device node.
6
7Note that these settings are applied after any phy-specific fixup from
8phy_fixup_list (see phy_init_hw() from drivers/net/phy/phy_device.c),
9and therefore may overwrite them.
10
11KSZ9021:
12
13  All skew control options are specified in picoseconds. The minimum
14  value is 0, the maximum value is 3000, and it is incremented by 200ps
15  steps.
16
17  Optional properties:
18
19    - rxc-skew-ps : Skew control of RXC pad
20    - rxdv-skew-ps : Skew control of RX CTL pad
21    - txc-skew-ps : Skew control of TXC pad
22    - txen-skew-ps : Skew control of TX CTL pad
23    - rxd0-skew-ps : Skew control of RX data 0 pad
24    - rxd1-skew-ps : Skew control of RX data 1 pad
25    - rxd2-skew-ps : Skew control of RX data 2 pad
26    - rxd3-skew-ps : Skew control of RX data 3 pad
27    - txd0-skew-ps : Skew control of TX data 0 pad
28    - txd1-skew-ps : Skew control of TX data 1 pad
29    - txd2-skew-ps : Skew control of TX data 2 pad
30    - txd3-skew-ps : Skew control of TX data 3 pad
31
32KSZ9031:
33
34  All skew control options are specified in picoseconds. The minimum
35  value is 0, and the maximum is property-dependent. The increment
36  step is 60ps.
37
38  Optional properties:
39
40    Maximum value of 1860:
41
42      - rxc-skew-ps : Skew control of RX clock pad
43      - txc-skew-ps : Skew control of TX clock pad
44
45    Maximum value of 900:
46
47      - rxdv-skew-ps : Skew control of RX CTL pad
48      - txen-skew-ps : Skew control of TX CTL pad
49      - rxd0-skew-ps : Skew control of RX data 0 pad
50      - rxd1-skew-ps : Skew control of RX data 1 pad
51      - rxd2-skew-ps : Skew control of RX data 2 pad
52      - rxd3-skew-ps : Skew control of RX data 3 pad
53      - txd0-skew-ps : Skew control of TX data 0 pad
54      - txd1-skew-ps : Skew control of TX data 1 pad
55      - txd2-skew-ps : Skew control of TX data 2 pad
56      - txd3-skew-ps : Skew control of TX data 3 pad
57
58Examples:
59
60	/* Attach to an Ethernet device with autodetected PHY */
61	&enet {
62		rxc-skew-ps = <3000>;
63		rxdv-skew-ps = <0>;
64		txc-skew-ps = <3000>;
65		txen-skew-ps = <0>;
66		status = "okay";
67	};
68
69	/* Attach to an explicitly-specified PHY */
70	mdio {
71		phy0: ethernet-phy@0 {
72			rxc-skew-ps = <3000>;
73			rxdv-skew-ps = <0>;
74			txc-skew-ps = <3000>;
75			txen-skew-ps = <0>;
76			reg = <0>;
77		};
78	};
79	ethernet@70000 {
80		status = "okay";
81		phy = <&phy0>;
82		phy-mode = "rgmii-id";
83	};
84