Ethernet cable plug in/out event with Zephyr and W5500

[Dymek117]

Good afternoon,

As mentioned in topic, I'm trying to detect moment of ethernet cable plug in and out from my application - I need this to immediately disconnect from wifi when cable is connected.
I'm using wiznet W5500 module and nrf5340. I have no network issues on this setup.

Here is what i already tried:
1) Detecting net events like NET_EVENT_L4_CONNECTED or NET_EVENT_L4_DISCONNECTED
This works only once - when cable connected and dhcp ip address assigned. After this events will not be triggered ever (nor for connect and disconnect).
2) Waiting for specific network event using net_mgmt_event_wait_on_iface. 
The same behaviour as in point 1.
3) Checking flags like net_if_flag_is_set(netif_get_interface(LAN_KEY), NET_IF_LOWER_UP).
None of this flag is being ever updated.


For all my tests i used code and .conf from NRF SDK samples. None of this were success however :/
Maybe you guys can help me, I guess there are some different ways doing that I am missing here.
Maybe there is simplier way of managing wifi/eth connection without detecting cablke plug in?

Thanks! Damian.

[ovrebekk]

Hi Damian

Using the conn_mgr library is not appropriate in this case since you need to choose a specific L2 layer, and conn_mgr will simply choose any L2 layer that is available. 

The main problem in this case is that the eth_w5500.c driver doesn't support link detection yet, but luckily this was patched in Zephyr just weeks ago: 
https://github.com/zephyrproject-rtos/zephyr/pull/68752

Once this is in place you can monitor the NET_EVENT_IF_UP and NET_EVENT_IF_DOWN events in order to check if the ethernet cable is connected or disconnected. 

For an example of how to do this please have a look at this code.

Best regards
Torbjørn

[Dymek117]

This patch absolutly fixed this issue. Network events works fine for wiznet now ;)
Thank you!

[ovrebekk]

That's great Damian, happy to hear that the patch solved it for you