Hi,

let us assume you want to determine which driver is behind a device. For example disk /dev/sdc

By udev. Query the device /dev/sdc by udevadm. Scroll down to the section for the pci device

root@devdeb ~# udevadm info -a -n /dev/sdc
.....
  looking at parent device '/devices/pci0000:00/0000:00:10.0':
    KERNELS=="0000:00:10.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="mptspi"
.....

or (the native way) by sysfs

root@devdeb ~# cd /sys/block/sdc
root@devdeb ~# cd -P /sys/block/sdc/device
/sys/devices/pci0000:00/0000:00:10.0/host2/target2:0:1/2:0:1:0 

Go to the pci device

root@devdeb ~# cd /sys/devices/pci0000:00/0000:00:10.0
root@devdeb ~#  ls -l driver
lrwxrwxrwx 1 root root 0 Dec 22 09:14 driver -> ../../../bus/pci/drivers/mptspi

Michael