Mechanism, the company behind a "gaming pillow" for the Steam Deck and a growing list of grips for handheld consoles and PCs, already has its first Steam Controller accessory ready. Valve's new controller will be available to purchase on May 4 , and that same day Mechanism will start selling the Basegrip for Steam Controller , an accessory that will let you attach the controller to a smartphone and plenty of other mounts the company already sells. The Basegrip for Steam Controller is contoured to fit snuggly over the back of the controller while leaving room for its magnetic charging puck to still attach. And because most of Mechanism's accessories are designed to work together, with the Basegrip attached, you could connect the Steam Controller to a large number of the company's existing mounts, including a phone mount that lets you magnetically attach a smartphone to the top of the controller. With a phone and controller together, you theoretically have a little handheld console for playing games.…