On 02/22/10 16:16, Guennadi Liakhovetski wrote: > On Mon, 22 Feb 2010, Rodolfo Giometti wrote: > >> On Fri, Feb 19, 2010 at 08:36:38PM +0100, Guennadi Liakhovetski wrote: >>> On Fri, 19 Feb 2010, Rodolfo Giometti wrote: >>> >>>> Hello, >>>> >>>> on my pxa27x based board I have a adv7180 connected with the CIF >>>> interface. Due this fact I'm going to use the pxa_camera.c driver >>>> which in turn registers a soc_camera_host. >>>> >>>> In the latest kernel I found your driver for the ADV7180, but it >>>> registers the chip as a v4l sub device. >>>> >>>> I suppose these two interfaces are not compatible, aren't they? >>> >>> Congratulations! Thereby you're in a position to develop the first >>> v4l2-subdev / soc-camera universal driver;) The answer to this your >>> question is - they are... kinda. This means - yes, soc-camera is also >>> using the v4l2-subdev API, but - with a couple of additions. Basically, >>> there are two things you have to change in the adv7180 driver to make it >>> compatible with soc-camera - (1) add bus-configuration methods, even if >>> they don't do much (see .query_bus_param() and .set_bus_param() methods >>> from struct soc_camera_ops), and (2) migrate the driver to the mediabus >>> API. The latter one requires some care - in principle, mediabus should be >>> the future API to negotiate parameters on the video bus between bridges >>> (in your case PXA CIF) and clients, but for you this means you also have >>> to migrate any other bridge drivers in the mainline to that API, and, if >>> they also interface to some other subdevices - those too, and if those can >>> also work with other bridges - those too...;) But, I think, that chain >>> will terminate quite soon, in fact, I cannot find any users of that driver >>> currently in the mainline, Richard? >>> >>>> In this situation, should I write a new driver for the >>>> soc_camera_device? Which is The-Right-Thing(TM) to do? :) >>> >>> Please, have a look and try to convert the driver as described above. All >>> the APIs and a few examples are in the mainline, so, you should have >>> enough copy-paste sources;) Ask on the list (with me on cc) if anything is >>> still unclear. >> >> Thanks for your quick answer! :) >> >> What I still don't understand is if should I move the driver form >> v4l2-subdev to a soc_camera device or trying to support both API... > > Both. It is just one (v4l2-subdev) API, but soc-camera is using some > extensions to it. > >> It seems to me that the driver is not used by any machines into >> mainline > > That makes your task even easier - you do not have to convert any bridge > drivers to mediabus API. Indeed. Having time to do that is what is delaying the ov7670 conversion. (that and having time in general!) For info I did post some untested patches for the ov7670 a while back that show the minimal changes I think are needed under these circumstances. > >> so if soc-camera is also using the v4l2-subdev API but with a >> couple of additions I suppose I can move it to soc_camera API... > > Not move, extend. But preserve an ability to function without soc-camera > additions too. I.e., the use of soc-camera extensions should be optional > in your driver. Look here > http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/11486/focus=11493 > for an example. > > 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 > -- 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
