Can I submit a paper to a call for paper and a call for workshops for the same conference?
Well, since papers are generally for finished work, and workshops are for improving work in progress, it might be looked at as an odd situation. If you submit a paper for what you have done already and a workshop proposal that is related, but, perhaps, an extension to the other then it would be more natural. 

So, in the exact form you suggest, I'd recommend not, but a variation might work out for you. A workshop is also valuable in that it would put you in contact with other researches with similar interests.