...and vice versa too, v4l2 is not about input devices only but it is
also related to output devices, v4l2 spec even has a special chapter
dedicated to overlays [1]. Moreover, you can find such a driver within
Freescale's BSP [2]. Another example is Omap's videoout driver [3].
Dmitry
[1]http://v4l2spec.bytesex.org/spec-single/v4l2.html#OVERLAY
[2]http://opensource.freescale.com/git?p=linux-2.6-mx.git;a=blob;f=drivers/media/video/mxc/output/mxc_v4l2_output.c;h=309700bb9d1f3b3f9dcac8a48a16d0775b8ed93a;hb=refs/heads/bsp-imx31ads-rel5
[3]http://git.omapzoom.org/?p=omapkernel.git;a=blob;f=drivers/media/video/omap/omap24xxvout.c;h=25ac1319bae58751cd1a543aa0f320159e10a475;hb=HEAD
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