AM62A7: Need help with device tree changes regarding ethernet connection for AM62A7 custom board.

Hi,

External Ethernet switches are not something that TI is able to directly support, TI does not have a set of exact steps to follow. We can make suggestions after you are able to create the DTS entries. Please note that users are able to attach these devices with success on a regular basis. I can make a couple of suggestions to start:

- Contact the switch vendor if they have example DTS file that could be used as a starting point for integrating with the TI processor.

- Contact the switch vendor for if they have a mainline Linux driver for the switch and what needs to be enabled in the kernel configuration to support the switch

- Assuming RGMII interface the switch would connect like an Ethernet PHY in terms of pin mux, please the existing TI EVM here.

- Place the CPSW port into fixed link mode, this is a possible example for setting the port at 100Mbps:

&cpsw_port2 {
status = "okay";
phy-mode = "rgmii-id";

fixed-link {
   speed = <100>;
   full-duplex;
  };
};

Best Regards,

Schuyler

Hi Schuyler Patton,

I contacted the switch vendor and got the device tree. As shown below, I have made the suggested changes in the device tree.

&cpsw3g {
     status = "okay";
     pinctrl-names = "default";
     pinctrl-0 = <&main_rgmii1_pins_default>;

     cpts@3d000 {
          /* MAP HW3_TS_PUSH to GENF1 */
          ti,pps = <7 1>;
     };
};

&main_spi2{
     pinctrl-names = "default";
     pinctrl-0 = <&main_spi2_pins_default>;
     status = "okay";

     ksz9477: ethernet-switch@0 {
          compatible = "microchip,ksz9477";
          reg = <0>;
          spi-max-frequency = <44000000>;
          spi-cpha;
          spi-cpol;
          reset-gpios = <&main_gpio1 40 GPIO_ACTIVE_LOW>;
          status = "okay";
          ports {
               #address-cells = <1>;
               #size-cells = <0>;
               port@0 {
                    reg = <0>;
                    label = "lan1";
               };
               port@1 {
                    reg = <1>;
                    label = "lan2";
               };
               port@2 {
                    reg = <2>;
                    label = "lan3";
               };
               port@3 {
                    reg = <3>;
                    label = "lan4";
               };
               port@4 {
                    reg = <4>;
                    label = "lan5";
               };
               sw_port5:port@5 {
                    reg = <5>;
                    label = "cpu";
                    ethernet = <&cpsw3g>;
                    phy-mode = "rgmii-rxid";
                    fixed-link {

                         speed = <10>;
                         full-duplex;
                    };
               };
          };
     };
};

&cpsw_port1 {
     status = "okay";
     phy-mode = "rgmii-rxid";
     phy-handle = <&ksz9477>;
     fixed-link {
          speed = <10>;
          full-duplex;
     };
};
              

When I boot up with these settings, it doesn't seem to affect anything on ethernet. I don't see any SPI-related logs or KSZ driver-related logs.                       

I confirm that I have made changes in the defconfig file to include KSZ SPI drivers for building. 

Can you please help me with this issue? What am I doing wrong in device tree?

Hi Sunil,

Sunil Kumar said:

 fixed-link {
          speed = <10>;
          full-duplex;
     };

Is your intention to bring up the interface speed at 10Mbps full-duplex?

Can you share your full device tree? Can you also share your full boot log?

Sunil Kumar said:

When I boot up with these settings, it doesn't seem to affect anything on ethernet.

Did you see any particular errors with these configuration settings? Does "ethtool eth0" or "ethtool eth1" show that the "Link detected: yes"?

-Daolin