On Thu, 18 Jun 2009, Valentin Longchamp wrote: > Hi Guennadi, > > I am trying to follow your developments at porting soc-camera to v4l2-subdev. > However, even if I understand quite correctly soc-camera, it is quite > difficult for me to get all the subtleties in your work. > > That's why I am asking you for a little help: when do you think would be the > best timing for me to add the mt9t031 camera support for mx31moboard within > your current process ? You can do this now, based either on the v4l tree, or wait for Linus to pull it - a pull request has been sent ba Mauro yesterday, looks like Linus hasn't pulled yet. The way you add your platform is going to change, and the pull, that I'm referring to above makes it possible for both "old style" and "new style" board camera data to work. Of course, it would be best for you to implement the "new style" platform data. You can do this by either looking at my patches, which I've posted to the lists earlier, and which are also included in my patch stack, which I announced yesterday. Or you can wait a bit until I update my pcm037 patch (going to do this now) and post it to arm-kernel. I'll (try not to forget to) add you to cc, that should be quite easy to follow for you. > I guess it should not be too difficult, I had done it before, and I can base > myself on what you have done for pcm037: > http://download.open-technology.de/soc-camera/20090617/0025-pcm037-add-MT9T031-camera-support.patch Yes, use this or wait a bit for an updated version. > Now I have a second question. On our robot, we physically have two cameras > (one looking to the front and one looking at a mirror) connected to the i.MX31 > physical bus. We have one signal that allows us to control the multiplexer for > the bus lines (video signals and I2C) through a GPIO. This now works with a > single camera declared in software and choices to the multiplexer done when no > image transfer is happening ( /dev/video is not open). What do you think > should be the correct way of dealing with these two cameras with the current > driver implementation (should I continue to declare only one camera in the > software) ? > > And do you think it could be possible to "hot-switch" from one camera to the > other ? My colleagues ask about it, I tell them that from my point of view > this seems not possible without changing the drivers, and even the drivers > would have to be changed quite heavily and it is not trivial. Do the cameras use different i2c addresses? If they use the same address I don't think you'd be able to register them simultaneously. If they do use different addresses, you can register both of them and use platform .power() callback to switch between them using your multiplexer. See arch/sh/boards/mach-migor/setup.c for an example. There was also a proposal to use switching input to select a data source, but this is currently unsupported by soc-camera. Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- 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
