LED configuration on USB ports - blink USB LED when accessing device

I have TP-Link Archer C2600 with OpenWrt 21.02.1.
I have changed the WiFi - LAN - WAN LEDs to be triggered by network activity (i.e. flashing) and would like to do something similar for the USB ports (i.e. when a USB device is accessed).

In LuCI, for WAN and LAN there is the option to select the "Network device activity" option, then the "Transmit" and "Receive" triggers. However, there is no similar option for the USB LEDs, as there's no such network device.
Is there any way to make USB LEDs blink when a USB device is accessed?

See the LED Configuration docs -

There are some USB examples there.

Yes I read that, but I can't find a trigger that flashes the USB LEDs when the connected USB device is being accessed.

You might look in /sys/class/leds -

I selected "disk-activity" but the usb led just remains completely off, even when I read/write to/from usb disk. Here are the available triggers, not sure what others do or if there's one that does what I want..

root@OpenWrt:~# cat /sys/class/leds/white:usb_4/trigger
none switch0 timer [disk-activity] disk-read disk-write ide-disk heartbeat default-on netdev usbport phy0rx phy0tx phy0assoc phy0radio phy0tpt phy1rx phy1tx phy1assoc phy1radio phy1tpt

What chipset is in the USB WiFi adapter you are talking about?

Not sure what your question is about. The router in question is TP-Link Archer C2600. I have external USB hard drive connected to its USB port.

bump.. still unresolved

You're saying thatn when you configure read or write for an LED, it still doesn't work?