Can you be a little more descriptive so that someone can help you.
Are u talking about in vitro specificity profiling / IC50 calculation or about just using it in cell culture for experiments or about checking whether an inhibitor is ATP-competitive?
Just to get quick and dirty assessment if your kinase inhibitor is ATP-independent, you will need to run concentration dependent inhibition curves for your compounds at two an order of magnitude different concentrations of ATP. If you see higher IC50 at higher ATP concentration that would indicated ATP-dependence, if no IC50 shift is observed, one can reasonably suggest ATP-independent inhibition.