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| -rw-r--r-- | Documentation/devicetree/bindings/net/micrel-ksz90x1.txt | 135 |
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diff --git a/Documentation/devicetree/bindings/net/micrel-ksz90x1.txt b/Documentation/devicetree/bindings/net/micrel-ksz90x1.txt new file mode 100644 index 000000000..b921731cd --- /dev/null +++ b/Documentation/devicetree/bindings/net/micrel-ksz90x1.txt @@ -0,0 +1,135 @@ +Micrel KSZ9021/KSZ9031/KSZ9131 Gigabit Ethernet PHY + +Some boards require special tuning values, particularly when it comes +to clock delays. You can specify clock delay values in the PHY OF +device node. Deprecated, but still supported, these properties can +also be added to an Ethernet OF device node. + +Note that these settings are applied after any phy-specific fixup from +phy_fixup_list (see phy_init_hw() from drivers/net/phy/phy_device.c), +and therefore may overwrite them. + +KSZ9021: + + All skew control options are specified in picoseconds. The minimum + value is 0, the maximum value is 3000, and it can be specified in 200ps + steps, *but* these values are in not fact what you get because this chip's + skew values actually increase in 120ps steps, starting from -840ps. The + incorrect values came from an error in the original KSZ9021 datasheet + before it was corrected in revision 1.2 (Feb 2014), but it is too late to + change the driver now because of the many existing device trees that have + been created using values that go up in increments of 200. + + The following table shows the actual skew delay you will get for each of the + possible devicetree values, and the number that will be programmed into the + corresponding pad skew register: + + Device Tree Value Delay Pad Skew Register Value + ----------------------------------------------------- + 0 -840ps 0000 + 200 -720ps 0001 + 400 -600ps 0010 + 600 -480ps 0011 + 800 -360ps 0100 + 1000 -240ps 0101 + 1200 -120ps 0110 + 1400 0ps 0111 + 1600 120ps 1000 + 1800 240ps 1001 + 2000 360ps 1010 + 2200 480ps 1011 + 2400 600ps 1100 + 2600 720ps 1101 + 2800 840ps 1110 + 3000 960ps 1111 + + Optional properties: + + - rxc-skew-ps : Skew control of RXC pad + - rxdv-skew-ps : Skew control of RX CTL pad + - txc-skew-ps : Skew control of TXC pad + - txen-skew-ps : Skew control of TX CTL pad + - rxd0-skew-ps : Skew control of RX data 0 pad + - rxd1-skew-ps : Skew control of RX data 1 pad + - rxd2-skew-ps : Skew control of RX data 2 pad + - rxd3-skew-ps : Skew control of RX data 3 pad + - txd0-skew-ps : Skew control of TX data 0 pad + - txd1-skew-ps : Skew control of TX data 1 pad + - txd2-skew-ps : Skew control of TX data 2 pad + - txd3-skew-ps : Skew control of TX data 3 pad + +KSZ9031: + + All skew control options are specified in picoseconds. The minimum + value is 0, and the maximum is property-dependent. The increment + step is 60ps. The default value is the neutral setting, so setting + rxc-skew-ps=<0> actually results in -900 picoseconds adjustment. + + Optional properties: + + Maximum value of 1860, default value 900: + + - rxc-skew-ps : Skew control of RX clock pad + - txc-skew-ps : Skew control of TX clock pad + + Maximum value of 900, default value 420: + + - rxdv-skew-ps : Skew control of RX CTL pad + - txen-skew-ps : Skew control of TX CTL pad + - rxd0-skew-ps : Skew control of RX data 0 pad + - rxd1-skew-ps : Skew control of RX data 1 pad + - rxd2-skew-ps : Skew control of RX data 2 pad + - rxd3-skew-ps : Skew control of RX data 3 pad + - txd0-skew-ps : Skew control of TX data 0 pad + - txd1-skew-ps : Skew control of TX data 1 pad + - txd2-skew-ps : Skew control of TX data 2 pad + - txd3-skew-ps : Skew control of TX data 3 pad + + - micrel,force-master: + Boolean, force phy to master mode. Only set this option if the phy + reference clock provided at CLK125_NDO pin is used as MAC reference + clock because the clock jitter in slave mode is to high (errata#2). + Attention: The link partner must be configurable as slave otherwise + no link will be established. + +KSZ9131: + + All skew control options are specified in picoseconds. The increment + step is 100ps. Unlike KSZ9031, the values represent picoseccond delays. + A negative value can be assigned as rxc-skew-psec = <(-100)>;. + + Optional properties: + + Range of the value -700 to 2400, default value 0: + + - rxc-skew-psec : Skew control of RX clock pad + - txc-skew-psec : Skew control of TX clock pad + + Range of the value -700 to 800, default value 0: + + - rxdv-skew-psec : Skew control of RX CTL pad + - txen-skew-psec : Skew control of TX CTL pad + - rxd0-skew-psec : Skew control of RX data 0 pad + - rxd1-skew-psec : Skew control of RX data 1 pad + - rxd2-skew-psec : Skew control of RX data 2 pad + - rxd3-skew-psec : Skew control of RX data 3 pad + - txd0-skew-psec : Skew control of TX data 0 pad + - txd1-skew-psec : Skew control of TX data 1 pad + - txd2-skew-psec : Skew control of TX data 2 pad + - txd3-skew-psec : Skew control of TX data 3 pad + +Examples: + + mdio { + phy0: ethernet-phy@0 { + rxc-skew-ps = <3000>; + rxdv-skew-ps = <0>; + txc-skew-ps = <3000>; + txen-skew-ps = <0>; + reg = <0>; + }; + }; + ethernet@70000 { + phy = <&phy0>; + phy-mode = "rgmii-id"; + }; |