Can you upload RAW files to Photos?

It depends on what system and iPhoto version you're running and which camera you're using. Give is that information and we can tell you what is needed to import those RAW files into iPhoto.

Yes, is you upgrade to Yosemite and Photos if your camera is listed in this Apple document you'll be able to import them: Digital camera RAW formats supported by OS X Yosemite - Apple Support

For your camera you need to apply the Digital Camera RAW Compatibility Update 6.03 and it requires Yosemite and iPhoto 9.6.1 or Photos.

You'll have to shoot just JPEG or use the Adobe RAW Convert to convert the raw files to .dng files which iPhoto can use as raw.