V4L2 sub-device userspace API

configname: CONFIG_VIDEO_V4L2_SUBDEV_API

Linux Kernel Configuration
└─>Device Drivers
└─>Multimedia support
└─>Video4Linux options
└─>V4L2 sub-device userspace API
In linux kernel since version 2.6.39 (release Date: 2011-05-18)  
Enables the V4L2 sub-device pad-level userspace API used to configure
video format, size and frame rate between hardware blocks.

This API is mostly used by camera interfaces in embedded platforms.