Ahh, that makes more sense.
I'm away on travel, so I don't have my notes with me, but _raw is definitely exported into the sysfs
If I remember correctly, the in_temp0_reading was in iio:device0/in_temp0_reading, while _raw was in iio:device1/in_temp0_raw (or something like that).
Thanks for the link, I have stumbled into the debugfs directory, but it's good to have a link to it.
Ultimately, this will be headless, so I won't be able to use the wiget, so being able to set values using the filesystem is very nice. Which I can do with sysfs and debugfs.