IMX6 Linux Kernel 3.10 Configuration to use RGMII with out PTP/ GPIO_16 ?

ssreeraj — Mon, 11 Aug 2014 23:38:18 GMT

I am using yocto to create SD card boot images for a custom imx6dl ( duallite ) board with hardware design identical to the Freescale SabreSDP reference board other than addition of a USB hub and removal of few peripherals such as camera and accelerometer. The Gigabit Ethernet circuit is identical to the Freescale reference board and uses RGMII.

I want to configure and compile the Linux kernel so that the PTP system (IEEE1588 Packet Timing Protocol) is not enabled for Ethernet - specifically I want to use the NVCC GPIO_16 for other purposes. On the 3.10.17-1.0.0 kernel, the GPIO_16 outputs a 50 MHz clock. The kernel config menu ( obtained by running "bitbake -c menuconfig linux-imx") automatically forces the PTP feature on if FEC Ethernet is enabled! There is no way to have just the Ethernet enabled for RGMII with clock supplied from the PHY on ENET_REF_CLK pin and not use the GPIO_16 pin. I believe that GPIO_16 is required only for RMII and not RGMII unless PTP feature is required.

Does anybody have a solution/ patch to achieve this?

I used the following to setup the kernel and SD card image compile:

---------------------------

repo init -u git://git.freescale.com/imx/fsl-arm-yocto-bsp.git -b imx-3.10.17-1.0.0_ga
repo sync

MACHINE=imx6dlsabresd source fsl-setup-release.sh -b build_sabresd_dl_min -e x11

bitbake core-image-base

The report had the lines:

Your build environemnt has been configured with:

    MACHINE=imx6dlsabresd
    SDKMACHINE=i686
    DISTRO=poky
    EULA=1

--------------------------

Thanks in advance.

Re: IMX6 Linux Kernel 3.10 Configuration to use RGMII with out PTP/ GPIO_16 ?

ssreeraj — Fri, 15 Aug 2014 10:59:46 GMT

Hi,

Any idea, any one?

Re: IMX6 Linux Kernel 3.10 Configuration to use RGMII with out PTP/ GPIO_16 ?

gusarambula — Fri, 22 Aug 2014 21:21:56 GMT

I would recommend leaving the GPIO_16 pin unused as in the SABRE board, if possible. This because of the internal muxing on this pin, as it’s connected to the ENET_CLK pad.

The RGMII implementation does require a 125MHz Reference Clock not necessarily on the GPIO_16 pin, but since it’s related to the ENET_CLK it’s possible that it could cause interference.

topic IMX6 Linux Kernel 3.10 Configuration to use RGMII with out PTP/ GPIO_16 ? in i.MX Processors

IMX6 Linux Kernel 3.10 Configuration to use RGMII with out PTP/ GPIO_16 ?

Re: IMX6 Linux Kernel 3.10 Configuration to use RGMII with out PTP/ GPIO_16 ?

Re: IMX6 Linux Kernel 3.10 Configuration to use RGMII with out PTP/ GPIO_16 ?