When to submit into drivers/staging

Hi, I have a question regarding driver submission into mainline. I'm not exactly sure if my driver is ready to be submittet into normal drivers or if it would be better to submit it to staging first. Is there any recomendation when to submit to drivers/staging instead of drivers? I've searched the archives but haven't found an answer to it. If you can instead just point me to a document I'm fine. The driver(s) in question is a bus driver for multi function FPGAs made by my company and one first iio/adc driver using this bus. It was sucessfully tested on x86 but is known to crash on powerpc because of my parser code (which will of cause be fixed when submitting, even into staging). Thanks a lot, Johannes