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Connect IMX6ul and KSZ8863RLL as standalone

Question asked by Cyril Roques on Oct 4, 2017
Latest reply on Oct 11, 2017 by Cyril Roques



We have some trouble to connect an Imx6-ul (MCIMX6G2AVM) with a KSZ8863RLL (ethernet switch). For our use case we would like the ethernet switch to be configured as standalone. The two ICs are connected throught  RMII interface without MDC/MDIO management interface, the clock is generated by the KSZ8863RLL. On imx6.UL side the ENET2 is used.


The base DTS is linux-2.6-imx/imx6ul-var-dart.dtsi at imx-rel_imx_4.1.15_1.1.0_ga-var02 · varigit/linux-2.6-imx · GitHub 


The DTS is modified as following

&fec1 {
    status = "disabled";

&fec2 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_enet2>;
    phy-mode = "rmii";
    status = "okay";

    fixed-link {
          speed = <100>;


We are unable to find the correct values to modify pinctrl_enet2: enet2grp  to correctly setup the clock settings (ENET2_TX_CLK as input) and clear bit 18 of GPR1 according documentation.


We are thinking that the problem is related to the value of MX6UL_PAD_ENET2_TX_CLK__ENET2_REF_CLK2, but we are not able to find where the value is described in documentation. At the other side we are found bit 18 of GPR1 to be cleared to enable ENET2_TX_CLK as input but we are unable to find the link with DTS


any advise would be appreciated


Thank you