Linux/AM3352: MDIO error

Part Number:AM3352

Tool/software: Linux

Hello, everybody.

I use SDK 04.00.00.04, and linux version is 4.9.28. After I set the ethernet to RMII mode and then I got the error like this:

[ 1.556382] davinci_mdio 4a101000.mdio: davinci mdio revision 1.6
[ 1.562893] davinci_mdio 4a101000.mdio: no live phy, scanning all
[ 1.569968] davinci_mdio: probe of 4a101000.mdio failed with error -5
[ 1.578211] cpsw 4a100000.ethernet: No slave[1] phy_id, phy-handle, or fixed-link property

The phy I used is dp83620.Following is my dts about ethernet:

cpsw_default: cpsw_default {
pinctrl-single,pins = <
/* Slave 1 */
AM33XX_IOPAD(0x90C, PIN_INPUT_PULLDOWN | MUX_MODE1) /* mii1_crs.rmii1_crs_dv */
AM33XX_IOPAD(0x910, PIN_INPUT_PULLDOWN | MUX_MODE1) /* mii1_rxerr.rmii1_rxerr */
AM33XX_IOPAD(0x914, PIN_OUTPUT | MUX_MODE1) /* mii1_txen.rmii1_txen */
AM33XX_IOPAD(0x924, PIN_OUTPUT | MUX_MODE1) /* mii1_txd1.rmii1_txd1 */
AM33XX_IOPAD(0x928, PIN_OUTPUT | MUX_MODE1) /* mii1_txd0.rmii1_txd0 */
AM33XX_IOPAD(0x944, PIN_INPUT_PULLDOWN | MUX_MODE0) /* mii1_refclk.rmii1_refclk */
AM33XX_IOPAD(0x93c, PIN_INPUT_PULLDOWN | MUX_MODE1) /* mii1_rxd1.rmii1_rxd1 */
AM33XX_IOPAD(0x940, PIN_INPUT_PULLDOWN | MUX_MODE1) /* mii1_rxd0.rmii1_rxd0 */
>;
};

cpsw_sleep: cpsw_sleep {
pinctrl-single,pins = <
/* Slave 1 reset value */
AM33XX_IOPAD(0x90C, PIN_INPUT_PULLDOWN | MUX_MODE7)
AM33XX_IOPAD(0x910, PIN_INPUT_PULLDOWN | MUX_MODE7)
AM33XX_IOPAD(0x914, PIN_INPUT_PULLDOWN | MUX_MODE7)
AM33XX_IOPAD(0x924, PIN_INPUT_PULLDOWN | MUX_MODE7)
AM33XX_IOPAD(0x928, PIN_INPUT_PULLDOWN | MUX_MODE7)
AM33XX_IOPAD(0x944, PIN_INPUT_PULLDOWN | MUX_MODE7)
AM33XX_IOPAD(0x93c, PIN_INPUT_PULLDOWN | MUX_MODE7)
AM33XX_IOPAD(0x940, PIN_INPUT_PULLDOWN | MUX_MODE7)
>;
};
davinci_mdio_default: davinci_mdio_default {
pinctrl-single,pins = <
/* MDIO */
AM33XX_IOPAD(0x948, PIN_INPUT_PULLUP | SLEWCTRL_FAST | MUX_MODE0) /* mdio_data.mdio_data */
AM33XX_IOPAD(0x94c, PIN_OUTPUT_PULLUP | MUX_MODE0) /* mdio_clk.mdio_clk */
>;
};

davinci_mdio_sleep: davinci_mdio_sleep {
pinctrl-single,pins = <
/* MDIO reset value */
AM33XX_IOPAD(0x948, PIN_INPUT_PULLDOWN | MUX_MODE7)
AM33XX_IOPAD(0x94c, PIN_INPUT_PULLDOWN | MUX_MODE7)
>;
};

&mac {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&cpsw_default>;
pinctrl-1 = <&cpsw_sleep>;
status = "okay";
};

&davinci_mdio {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&davinci_mdio_default>;
pinctrl-1 = <&davinci_mdio_sleep>;
status = "okay";
};

&cpsw_emac0 {
phy_id = <&davinci_mdio>, <5>;
phy-mode = "rmii";
};

&phy_sel {
rmii-clock-ext;
};

Is there any error in my dts? How can I deal the problem? 

Thanks!