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KSZ9893 Ethernet Switch on iMX8mq Custom board

Question asked by Thinh Nguyen on Jul 23, 2019
Latest reply on Nov 8, 2019 by Thinh Nguyen

KSZ9893 is a 3 port ethernet switch; port 1 and 2 incorporate 10/100/1000 Mbps PHYs. Port 3 has interfaces that can be configured as RGMII, MII or RMII. Port 3 is connected directly to iMX8mq. 



Because Port 3 does not have PHY, so I think cannot treat it as an ethernet tranciver (eg. AR8031 in imx8mq-evk). I do some modify in kernel device tree but it still not working; cannot obtain IP address too.



&fec1 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_fec1>;
    phy-mode = "rgmii-txid";
    // don't  use PHY handle
    // phy-handle = <&ethphy0>;
    status = "okay";
    // Add Ethernet Fixed link
    fixed-link {
     speed = <1000>;
     // Remove MIDO


There is 125 MHz on both TX Clock and RX Clock; Already measured by oscilloscope. It still cannot obtain IP address.

If anyone who has experience on ethernet switch, please help. My kernel version is 4.9.123.

Thank all,