topic Re: imx6ul external ethernet clock in i.MX Processors

imx6ul external ethernet clock

wimdewitte — Fri, 02 Sep 2016 12:28:11 GMT

Our custom board has a KSZ8081RNA with connected crystal. REF_CLK from the PHY outputs the clock signal which is used as input on the imx6ul. Thus, the clock direction is the opposite as on the development board.

On the imx6ul, pin enet1_tx_clk should behave as an input and not as an output.

In u-boot it was fairly simple to get this setup working: do not call function setup_fec.

But how do I manage this in linux? via the dts?

I'm using a 4.4 mainline kernel, but this problem makes no difference compared to the nxp fork.

Re: imx6ul external ethernet clock

igorpadykov — Sun, 04 Sep 2016 23:24:28 GMT

Hi Wim

please check linux/arch/arm/mach-imx/mach-imx6ul.c
function imx6ul_enet_clk_init()
http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/arch/arm/mach-imx/mach-imx6ul.c?id=rel_imx_4.1.15_1.2.0_ga

Best regards
igor
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Re: imx6ul external ethernet clock

ranjithhebbar — Thu, 31 May 2018 05:07:12 GMT

Dear igor,

We do have a similar setup, REF_CLK from the PHY outputs the clock signal which is used as input on the imx6ul. Crystal Osc is used as input to the PHY. We did the similar change as above like in U-boot did not call function setup_fec and in linux we didn't call function imx6ul_enet_clk_init(). But even though, we were not able to ping.

You are suggestion is really helpful for us.

Best Regards,

Ranjith