how to use rmii with 50MHz clk from phy?

[changbaoma]

The mx6ull evk board use rmii 50MHz clk from MAC to phy. But in our hardware design use rmii with 50MHz clk from phy. i change u-boot/board/freescale/mx6ullevk/mx6ullevk.c

eg. FEC1(ENET2). 

static iomux_v3_cfg_t const fec2_pads[] = {
MX6_PAD_GPIO1_IO06__ENET2_MDIO | MUX_PAD_CTRL(MDIO_PAD_CTRL),
MX6_PAD_GPIO1_IO07__ENET2_MDC | MUX_PAD_CTRL(ENET_PAD_CTRL),

MX6_PAD_ENET2_TX_DATA0__ENET2_TDATA00 | MUX_PAD_CTRL(ENET_PAD_CTRL),
MX6_PAD_ENET2_TX_DATA1__ENET2_TDATA01 | MUX_PAD_CTRL(ENET_PAD_CTRL),
-MX6_PAD_ENET2_TX_CLK__ENET2_REF_CLK2 | MUX_PAD_CTRL(ENET_CLK_PAD_CTRL),
+MX6_PAD_ENET2_TX_CLK__ENET2_TX_CLK | MUX_PAD_CTRL(ENET_CLK_PAD_CTRL),
MX6_PAD_ENET2_TX_EN__ENET2_TX_EN | MUX_PAD_CTRL(ENET_PAD_CTRL),

MX6_PAD_ENET2_RX_DATA0__ENET2_RDATA00 | MUX_PAD_CTRL(ENET_PAD_CTRL),
MX6_PAD_ENET2_RX_DATA1__ENET2_RDATA01 | MUX_PAD_CTRL(ENET_PAD_CTRL),
MX6_PAD_ENET2_RX_EN__ENET2_RX_EN | MUX_PAD_CTRL(ENET_PAD_CTRL),
MX6_PAD_ENET2_RX_ER__ENET2_RX_ER | MUX_PAD_CTRL(ENET_PAD_CTRL),
};

and

static int setup_fec(int fec_id)
{
        struct iomuxc *const iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
        int ret;

        if (fec_id == 0) {

                   ....

         } else {
                   /*
                  * Use 50M anatop loopback REF_CLK2 for ENET2,
                  * clear gpr1[14], set gpr1[18].
                  */

-                  clrsetbits_le32(&iomuxc_regs->gpr[1], IOMUX_GPR1_FEC2_MASK,
-                                                  IOMUX_GPR1_FEC2_CLOCK_MUX1_SEL_MASK);

-

+                  /* clk from phy, set gpr1[14], clear gpr1[18] */
+                  clrsetbits_le32(&iomuxc_regs->gpr[1], IOMUX_GPR1_FEC2_MASK,
+                  IOMUX_GPR1_FEC2_CLOCK_MUX2_SEL_MASK);

       }

...

}

But i can't make FEC1 work in u-boot.

May i miss something?

[igorpadykov]

Hi changbao

please check signal with oscilloscope, also

what uboot release used in the case, one can try latest from

source.codeaurora.org/external/imx/linux-imx  repository

mx6ullevk.c\mx6ullevk\freescale\board - uboot-imx - i.MX U-Boot 

check CONFIG_FEC_ENET_DEV

mx6ullevk.h\configs\include - uboot-imx - i.MX U-Boot 

Best regards
igor
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[changbaoma]

Yes, I can see 50MHz clk signal  from PHY to imx6ull pad  ENET2_TX_CLK with oscilloscope.

The u-boot version i use is uboot-imx-imx_v2016.03_4.1.15_2.0.0_ga.

can you tell me in the latest u-boot which borad use rmii with 50MHz clk forn Phy to Mac?