v4l2: enumerate output ports and add a property to select input/output
Submitted by Aurélien Zanelli
V4L2 device can have multiple input/output port and they expose them through ENUMINPUT/ENUMOUTPUT ioctls. But currently we only enumerate input whatever device is a capture one or an output one. I think, we should enumerate according to the device type.
Also I think it can be useful to enable user to select which input/output they want to use. To solve this I propose to add a property to v4l2object to let user select input/output.
I found this while playing with Vivid which have multiple input/output port.