summaryrefslogtreecommitdiffstats
path: root/Documentation/devicetree/bindings/net/micrel-ksz90x1.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/devicetree/bindings/net/micrel-ksz90x1.txt')
-rw-r--r--Documentation/devicetree/bindings/net/micrel-ksz90x1.txt135
1 files changed, 135 insertions, 0 deletions
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";
+ };