If you don't know what type of controller you're using, you can use the pci utility to identify it.
For example:
pci -vvv | less
The output from this command looks something like this:
Class = Mass Storage (IDE) Vendor ID = 8086h, Intel Corporation Device ID = 7111h, 82371AB/EB PIIX4 IDE Controller PCI index = 0h Class Codes = 010180h Revision ID = 1h Bus number = 0 Device number = 4 Function num = 1 Status Reg = 280h Command Reg = 5h I/O space access enabled Memory space access disabled Bus Master enabled Special Cycle operations ignored Memory Write and Invalidate disabled Palette Snooping disabled Parity Checking disabled Data/Address stepping disabled SERR# driver disabled Fast back-to-back transactions to different agents disabled Header type = 0h Single-function BIST = 0h Build-in-self-test not supported Latency Timer = 20h Cache Line Size= 0h PCI IO Address = d800h length 16 enabled Max Lat = 0ns Min Gnt = 0ns PCI Int Pin = NC Interrupt line = 0 Device Dependent Registers: 0x40: 07 c0 03 80 00 00 00 00 05 00 02 02 00 00 00 00 0x50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xA0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xB0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xC0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xD0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xE0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0xF0: 00 00 00 00 00 00 00 00 30 0f 00 00 00 00 00 00
Find the entry for the device you want to locate and it'll give you the details on the manufacturer/vendor ID and device ID. You may need to search for keywords (e.g., Audio) in order to identify your device.
You can search the manufacturer's website for information, or use the vendor and device IDs to cross-reference with /usr/include/hw/pci_devices.h. You can also search https://www.pcilookup.com/.