On Monday 22 February 2010 17:01:39 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... > > It seems to me that the driver is not used by any machines into > mainline 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... The long-term goal is to remove the last soc-camera API dependencies from the sensor subdev drivers. Subdevice (usually i2c) drivers should be fully reusable and a dependency on soc-camera defeats that goal. I think the only missing piece is low-level bus setup (i.e. sync polarities, rising/falling edge sampling, etc.). Some proposals were made, but basically nobody has had the time to actually implement this. Right now, if you want to use your sensor with soc-camera, then you need to support the soc-camera API (or what is left of it) in your subdev driver as well. Regards, Hans > > Is that right? > > Ciao, > > Rodolfo > > -- Hans Verkuil - video4linux developer - sponsored by TANDBERG -- 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
