Someone might know the answer; Otherwise I plan to look sometime tomorrow. I want to change the tuner frequency from within a program. Someone who'd done Linux stuff before might guess that drivers/char/radio-empeg.c implements a driver for /dev/radio and that the VIDIOCSFREQ ioctl would be what one wants. However, it's not compiled into Hijack, which means that's not what the player is doing.

Did I:
1) guess wrong on device name
2) miss some other interface for doing this that I should be using
3) incorrectly assume the player isn't monkeying on the i2c bus itself and just try compiling the module in

If no one knows, well, perhaps over the weekend I'll have some time and visit the car with a serial cable and try it.

radio-empeg.c is for the Mk1's internal FM radio I believe.

The Mk2 must just send out commands on the tuner's serial port and not have a kernel driver for it.

radio-empeg.c is for the Mk1's internal FM radio I believe.

I considered that, but that module isn't compiled in for hijack for mk1 kernels either, so the player must be "special" regardless.

Yay?

? I've not personally tried it, but it's definately turned on in the config for the Mk1. It's not compiled in the Mk2 however.

jade:~/empeg/hijack/v300/arch/arm/def-configs$ grep CONFIG_RADIO_EMPEG empeg-car1
CONFIG_RADIO_EMPEG=y

jade:~/empeg/hijack/v300/arch/arm/def-configs$ grep CONFIG_RADIO_EMPEG empeg-car2

jade:~/empeg/hijack/v300/drivers/char$ grep CONFIG_RADIO_EMPEG Config.in
dep_tristate 'empeg-car FM Radio support' CONFIG_RADIO_EMPEG $CONFIG_VIDEO_DEV

You're right. I'm blind.

Eh. I guess the answer is trace tuner + fake tuner plus sit around tuning to different stations and seeing what happens.