This article takes Forlinx Embedded’s OK-MX9352-C development board as an example to elaborate on how to adapt the network port module through the SPI interface to achieve Ethernet communication. The W5500 module, a high-performance SPI to 100Mbps Ethernet chip with up to 80Mbps data rate, suits embedded network needs.

Modules used:

Hardware Connection

Wiring between W5500 and OK-MX9352-C is in the table below.

Among them, SCS is the chip-select signal, MISO is the master-in slave-out data line, MOSI is the master-out slave-in data line, SCLK is the clock signal, INT is the interrupt signal, and RST is the reset signal.

Software Configuration and Driver Debugging

1. Compilation Drive

First, add the relevant options to the kernel configuration

> Device Drivers 
     > Network device support 
         > Ethernet driver support
             ......
             [*]   WIZnet devicesWIZnet W5100 Ethernet support                                                                                 			< >     WIZnet W5300 Ethernet support
            WIZnet interface mode (Select interface mode in runtime)  --->WIZnet W5100/W5200/W5500 Ethernet support for SPI mode
            ......

2. Devie Tree Modification‌

Add the relevant configuration of W5500 under SPI3 node.

&lpspi3 {
    fsl,spi-num-chipselects =;
    pinctrl-names = "default", "sleep";
    pinctrl-0 = <&pinctrl_lpspi3>;
    pinctrl-1 = <&pinctrl_lpspi3>;
    cs-gpios = <&gpio2 8 GPIO_ACTIVE_LOW>;
    status = "okay";
    
    ethernet: w5500@0 {
        compatible = "wiznet,w5500";
        reg =;
        status = "okay";
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_w5500>;
        interrupt-parent = <&gpio2>;
        interrupts =;
        spi-max-frequency =;
    };
};

Multiplexed SPI

 pinctrl_lpspi3: lpspi3grp {
        fsl,pins = < MX93_PAD_GPIO_IO08__GPIO2_IO08 0x3fe MX93_PAD_GPIO_IO09__LPSPI3_SIN 0x3fe MX93_PAD_GPIO_IO10__LPSPI3_SOUT 0x3fe MX93_PAD_GPIO_IO11__LPSPI3_SCK 0x3fe >;
    };
    pinctrl_w5500: w5500grp {
        fsl,pins = < MX93_PAD_GPIO_IO04__GPIO2_IO04 0x31e //int MX93_PAD_GPIO_IO05__GPIO2_IO05 0x31e //rst >;
    };

Since the W5500 driver uses software reset by default, it’s only necessary to ensure that the reset pin is in a pull-up state.

3. Compilation&Porting

Compile the device tree and drivers, including w5100.ko and w5100-SPI. Ko for W5500.

$ root@DESKTOP-GJ47EH8:/home/OKMX93-linux-sdk# ./build.sh kernel

After compiling, replace the device tree on the development board and place the driver in the directory where the system can find it.

$ root@ok-mx93:~# cp /run/media/boot-mmcblk1p1/OK-MX93-C.dtb /run/media/Boot-mmcblk0p1/
$ root@ok-mx93:~# cp /run/media/boot-mmcblk1p1/w5100.ko ./
$ root@ok-mx93:~# cp /run/media/boot-mmcblk1p1/w5100-spi.ko ./

4. Driver Loading‌

Execute the load driver command on the development board

root@ok-mx93:~# insmod w5100.ko
root@ok-mx93:~# insmod w5100-spi.ko

The new eth2 network card can be seen through the ifconfig -a command, and the network card can be up normally.

root@ok-mx93:~# ifconfig -a
...
eth2: flags=-28605  mtu 1500
        inet 169.254.218.84  netmask 255.255.0.0  broadcast 169.254.255.255
        inet6 fe80::c4c5:86ff:fe12:9f9d  prefixlen 64  scopeid 0x20ether c6:c5:86:12:9f:9d  txqueuelen 1000  (Ethernet)
        RX packets 2115  bytes 340022 (332.0 KiB)
        RX errors 0  dropped 133  overruns 0  frame 0
        TX packets 56  bytes 13927 (13.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
...
root@ok-mx93:~# ifconfig eth2 up
root@ok-mx93:~# ifconfig
...
eth2: flags=-28605  mtu 1500
        inet 169.254.218.84  netmask 255.255.0.0  broadcast 169.254.255.255
        inet6 fe80::c4c5:86ff:fe12:9f9d  prefixlen 64  scopeid 0x20ether c6:c5:86:12:9f:9d  txqueuelen 1000  (Ethernet)
        RX packets 2430  bytes 398823 (389.4 KiB)
        RX errors 0  dropped 158  overruns 0  frame 0
        TX packets 56  bytes 13927 (13.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
...

5. Network Test

After the driver is loaded, IP can be set normally and the external network can be pinged.

root@ok-mx93:~# ifconfig eth2 172.20.2.167
root@ok-mx93:~# ifconfig
...
eth2: flags=-28605  mtu 1500
        inet 172.20.2.167  netmask 255.255.0.0  broadcast 172.20.255.255
        inet6 fe80::c4c5:86ff:fe12:9f9d  prefixlen 64  scopeid 0x20ether c6:c5:86:12:9f:9d  txqueuelen 1000  (Ethernet)
        RX packets 8082  bytes 1529102 (1.4 MiB)
        RX errors 0  dropped 491  overruns 0  frame 0
        TX packets 94  bytes 31366 (30.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
...
root@ok-mx93:~# ping -I eth2 172.20.2.166
PING 172.20.2.166 (172.20.2.166) from 172.20.2.166 eth2: 56(84) bytes of data.
64 bytes from 172.20.2.166: icmp_seq=1 ttl=64 time=0.127 ms
64 bytes from 172.20.2.166: icmp_seq=2 ttl=64 time=0.077 ms
64 bytes from 172.20.2.166: icmp_seq=3 ttl=64 time=0.077 ms
64 bytes from 172.20.2.166: icmp_seq=4 ttl=64 time=0.076 ms
^C
--- 172.20.2.166 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3076ms
rtt min/avg/max/mdev = 0.076/0.089/0.127/0.021 ms

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