On Thu, 16 Apr 2009, Dongsoo, Nathaniel Kim wrote: > Hello, > > I'm planing to make a new camera interface driver for S3C64XX from Samsung. > Even if it already has a driver, it seems to be re-designed for some > reasons. If you are interested in, take a look at following repository > (http://git.kernel.org/?p=linux/kernel/git/eyryu_ap/samsung-ap-2.6.24.git;a=summary) > drivers/media/video/s3c_* files > > Before beginning to implement a new driver for that, I need to clarify > some of features about how to implement in driver. > > Please take a look at the diagram on page 610 of following user manual > of s3c6400. > http://www.ebv.com/fileadmin/products/Products/Samsung/S3C6400/S3C6400X_UserManual_rev1-0_2008-02_661558um.pdf > > It seems to have a couple of path for camera data named codec and > preview, and they could be used at the same time. > It means that it has no problem making those two paths into > independent device nodes like /dev/video0 and /dev/video1 > > But there is a limit of size using both of paths at the same time. I > mean, If you are using preview path and camera sensor is running with > 1280*720 resolution (which seems to be the max resolution could be > handled by preview path), codec path can't use resolution bigger than > 1280*720 at the same time because camera sensor can't produce > different resolution at a time. > > And also we should face a big problem when we are making dual camera > system with s3c64xx. Dual camera with single camera interface has some > restriction using clock and data path, because they have to be shared > between both of cameras. > I suppose to handle them with VIDIOC_S_INPUT and G_INPUT. And with > those, we can handle dual camera with single camera interface in a > decent way. > > But the thing is that there should be a problem using dual camera with > preview and codec path of s3c64xx. Even if we have each preview, and > codec device node and can't open them concurrently when user is > attempting to open each camera sensor like "camera A with preview node > and camera B with codec node". Because both of those camera sensors > are sharing same data path and clock source, and s3c64xx camera > interface only can handle one camera at a time. > > So, what I am concerned is how to make it a elegant driver which has > two device nodes handling multiple sensors as input devices. > Sounds complicated but I'm asking you to help me with any opinion > about designing this driver. Any opinion about these issues will be > greatly helpful to me. Ok, now I understand your comments to my soc-camera thread better. Now, what about making one (or more) video devices with V4L2_CAP_VIDEO_CAPTURE type and one with V4L2_CAP_VIDEO_OUTPUT? Then you can use your capture type devices to switch between cameras and to configure input, and your output device to configure preview? Then you can use soc-camera to control your capture devices (if you want to of course) and implement an output device directly. It should be a much simpler device, because it will not be communicating with the cameras and only modify various preview parameters. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
