Valve on the Steam Dev Days announced a small collaboration with the Sony in the USA this week with a plan to allow to use the DUALSHOCK 4 for PS4 controller on the Steam games where the additional controllers are supported.

Since Steam already has its own controller it wouldn’t be a big problem to make officially compatible the games with the Sony’s controller. At the moment it is nothing more than just a plan and don’t know when can you can use the Sony’s controller on the Steam games.
But one thing is sure, you will be able to use the controller only if you bought the game from the Steam Store.

Of course you can buy the games legally from other online distributors but Valve going to supports the DUALSHOCK 4 controller usage only for the Steam version games.
More information coming soon! Stay tuned!