The Steam Controller is one of the topics of discussion at Valve's SteamDevDays developer conference in Seattle this week. Jeff Bellinghausen from the Steam Controller team at Valve delivered a presentation on the Steam Controller, including information on upcoming support for the Sony's PlayStation 4 DualShock 4 controller. Gamasutra has a transcript of the presentation here.
An upcoming update will add full support for the DualShock 4 to the Steam Controller API, including configuration of the controller's integrated touchpad and gyroscopic sensor. Valve claims the DualShock4 will behave identically to a Steam Controller. The company also says that "existing native support for the PS4 controller on the PC is a bit weak; in this case Steam itself is communicating directly with the device so everything that's nice and reliable [sic]".
Valve promises that other controllers will be supported in the future, but did not comment on dates or which devices would receive support. We expect this refers primarily to Xbox One controllers, but hopefully also to other devices from companies like Logitech, Razer, and Nvidia.
Other highlights of the Valve presentation include information on the benefits developers receive from using the Steam Controller API and sales figures of the Steam Controller. Valve says it has sold over 500,000 controllers to date and expects to ship over a million by early 2017.