Using atmel-isi for direct output on framebuffer ?

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello Josh,

I am currently looking at V4L2 and your atmel-isi driver for an AT91
based platform on which I would like the ISI interface to capture the
image from a camera and have this image directly output in RGB format
at a specific location on the screen (so that it can be nicely
integrated into a Qt application for example).

At the moment, I grab frames from the V4L2 device to userspace, do the
YUV -> RGB conversion manually in my application, and then displays the
converted frame on the framebuffer thanks to normal Qt painting
mechanisms. This works, but obviously consumes a lot of CPU.

>From the AT91 datasheet, I understand that the ISI interface is capable
of doing the YUV -> RGB conversion and is also capable of outputting
the frame at some location in the framebuffer, but I don't see how to
use this capability with the Linux V4L2 and framebuffer infrastructures.

Is this possible ? If so, could you provide some pointers or starting
points to get me started ? If not, what is missing in the driver ?

Thanks a lot,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com