You can do all your Raw processing in Digital Photo Professional (DPP). After that you can, if needed, send the file to Photoshop using the Tools/Transfer to Photoshop function. The image will open in the Photoshop editor as a tiff (it won't save the tiff until you save it in Photoshop.
The reason you can't open the Raw file in Photoshop is likely that your camera is newer than the version of Photoshop you are using -- you can run the Bridge Help/Update utility to see if that helps, but otherwise DPP should do just fine. When you process a Raw file in DPP, the adjustments will not be available outside of DPP until you either do the Transfer to Photoshop function or, alternatively, do a Convert and Save (or Batch Process) and convert to a tiff or jpeg.
But just be aware that DPP has some very nice processing capabilities for those Raw files. Take the time to learn to use the tools and you may find little need for Photoshop.