1Micrel KSZ9021/KSZ9031/KSZ9131 Gigabit Ethernet PHY
2
3Some boards require special tuning values, particularly when it comes
4to clock delays. You can specify clock delay values in the PHY OF
5device node. Deprecated, but still supported, these properties can
6also be added to an Ethernet OF device node.
7
8Note that these settings are applied after any phy-specific fixup from
9phy_fixup_list (see phy_init_hw() from drivers/net/phy/phy_device.c),
10and therefore may overwrite them.
11
12KSZ9021:
13
14  All skew control options are specified in picoseconds. The minimum
15  value is 0, the maximum value is 3000, and it is incremented by 200ps
16  steps.
17
18  Optional properties:
19
20    - rxc-skew-ps : Skew control of RXC pad
21    - rxdv-skew-ps : Skew control of RX CTL pad
22    - txc-skew-ps : Skew control of TXC pad
23    - txen-skew-ps : Skew control of TX CTL pad
24    - rxd0-skew-ps : Skew control of RX data 0 pad
25    - rxd1-skew-ps : Skew control of RX data 1 pad
26    - rxd2-skew-ps : Skew control of RX data 2 pad
27    - rxd3-skew-ps : Skew control of RX data 3 pad
28    - txd0-skew-ps : Skew control of TX data 0 pad
29    - txd1-skew-ps : Skew control of TX data 1 pad
30    - txd2-skew-ps : Skew control of TX data 2 pad
31    - txd3-skew-ps : Skew control of TX data 3 pad
32
33KSZ9031:
34
35  All skew control options are specified in picoseconds. The minimum
36  value is 0, and the maximum is property-dependent. The increment
37  step is 60ps. The default value is the neutral setting, so setting
38  rxc-skew-ps=<0> actually results in -900 picoseconds adjustment.
39
40  Optional properties:
41
42    Maximum value of 1860, default value 900:
43
44      - rxc-skew-ps : Skew control of RX clock pad
45      - txc-skew-ps : Skew control of TX clock pad
46
47    Maximum value of 900, default value 420:
48
49      - rxdv-skew-ps : Skew control of RX CTL pad
50      - txen-skew-ps : Skew control of TX CTL pad
51      - rxd0-skew-ps : Skew control of RX data 0 pad
52      - rxd1-skew-ps : Skew control of RX data 1 pad
53      - rxd2-skew-ps : Skew control of RX data 2 pad
54      - rxd3-skew-ps : Skew control of RX data 3 pad
55      - txd0-skew-ps : Skew control of TX data 0 pad
56      - txd1-skew-ps : Skew control of TX data 1 pad
57      - txd2-skew-ps : Skew control of TX data 2 pad
58      - txd3-skew-ps : Skew control of TX data 3 pad
59
60    - micrel,force-master:
61        Boolean, force phy to master mode. Only set this option if the phy
62        reference clock provided at CLK125_NDO pin is used as MAC reference
63        clock because the clock jitter in slave mode is to high (errata#2).
64        Attention: The link partner must be configurable as slave otherwise
65        no link will be established.
66
67KSZ9131:
68
69  All skew control options are specified in picoseconds. The increment
70  step is 100ps. Unlike KSZ9031, the values represent picoseccond delays.
71  A negative value can be assigned as rxc-skew-psec = <(-100)>;.
72
73  Optional properties:
74
75    Range of the value -700 to 2400, default value 0:
76
77      - rxc-skew-psec : Skew control of RX clock pad
78      - txc-skew-psec : Skew control of TX clock pad
79
80    Range of the value -700 to 800, default value 0:
81
82      - rxdv-skew-psec : Skew control of RX CTL pad
83      - txen-skew-psec : Skew control of TX CTL pad
84      - rxd0-skew-psec : Skew control of RX data 0 pad
85      - rxd1-skew-psec : Skew control of RX data 1 pad
86      - rxd2-skew-psec : Skew control of RX data 2 pad
87      - rxd3-skew-psec : Skew control of RX data 3 pad
88      - txd0-skew-psec : Skew control of TX data 0 pad
89      - txd1-skew-psec : Skew control of TX data 1 pad
90      - txd2-skew-psec : Skew control of TX data 2 pad
91      - txd3-skew-psec : Skew control of TX data 3 pad
92
93Examples:
94
95	mdio {
96		phy0: ethernet-phy@0 {
97			rxc-skew-ps = <3000>;
98			rxdv-skew-ps = <0>;
99			txc-skew-ps = <3000>;
100			txen-skew-ps = <0>;
101			reg = <0>;
102		};
103	};
104	ethernet@70000 {
105		phy = <&phy0>;
106		phy-mode = "rgmii-id";
107	};
108