I am getting unsupported parameter combination CGBitmap error with swift

Just in case somebody is running into the same problem. The snippet below finally works.

let colorSpace:CGColorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapInfo = CGBitmapInfo(CGImageAlphaInfo.PremultipliedLast.rawValue)
let context = CGBitmapContextCreate(nil, UInt(rect.size.width), UInt(rect.size.height), 8, 0, colorSpace, bitmapInfo)

It generates a 32 bit RGBA context in swift