about CS-E9302 ac97 driver

Hi all !

I’m using CS-E9302 with linux-2.6.24-rc8, but the kernel source lacks

cirrus’s ac97 and I2S driver, are there any patch for this driver?

on the OLIMEX CS-E9302 PCB has IC3, and it is not assembled, but I don’t see the symbol of this IC in the schematic , what’s the purpose of this IC ?

Please patient of my bad English ! Thank for helping !