ethtool -i <network card>

<network card> can be eth0 etc.

Example output:

driver: e1000\\
version: 7.3.21-k4.1-NAPI\\
firmware-version: N/A\\
bus-info: 0000:02:00.0

The bus-info can be coupled with lspci

 lspci -s -v "2:"

Where 2: is taken from ethtool bus-info.

02:00.0 Ethernet controller: Intel Corporation 82545EM Gigabit Ethernet Controller (Copper) (rev 01)
      Subsystem: VMware PRO/1000 MT Single Port Adapter
      Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 59
      Memory at d8920000 (64-bit, non-prefetchable) [size=128K]
      Memory at d8900000 (64-bit, non-prefetchable) [size=64K]
      I/O ports at 2000 [size=64]
      [virtual] Expansion ROM at dc400000 [disabled] [size=64K]
      Capabilities: [dc] Power Management version 2
      Capabilities: [e4] PCI-X non-bridge device