check if a port is USB 2.0 or 3.0

$ sudo lsusb -v | grep -iE "Bus|^Device Desc|bcdusb"
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Device Descriptor:
  bcdUSB               2.00
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Device Descriptor:
  bcdUSB               2.00
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Device Descriptor:
  bcdUSB               1.10
...
...
Bus 010 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Device Descriptor:
  bcdUSB               3.00

1.10, 2.10, 3.10 = "Always powered" USB port.