The PS4’s Dualshock 4 (DS4), the default controller it uses, is a really nice controller to use and is up to the par, if not better than the standard Xbox 360 or Xbox One controllers. However, unlike the Xbox controllers, the Dualshock 4 requires some set-up and installation of third-part software to fully utilise it on PC.
Valve is taking one step to address this issue. Announced at Steam Dev Days, a developer convention by Valve, access to full configuration of other controllers other than the Steam controller will be added via a future Steam update. The touchpad and gyro controls of the controller will also be supported as well, since the Steam controller also has similar functions.
This means that you should be able to just plug or pair up your DS4 to a PC and it will just work on Steam. No need to mess with installing third-party software.
Similar support for other controllers will be coming soon as well, so expect to have more customisation for controls via Steam for more controllers in the future.