Hi Hans and Pavel, On Fri, Apr 29, 2016 at 09:31:51AM +0200, Hans Verkuil wrote: > On 04/29/2016 09:15 AM, Pavel Machek wrote: > > Hi! > > > >> On n900, probe finishes ok (verified by adding printks), and the > >> device shows up in /sys, but I don't get /dev/video* or > >> /dev/v4l-subdev*. > >> > >> Other drivers (back and front camera) load ok, and actually work. Any > >> idea what could be wrong? > > > > Ok, so I guess I realized what is the problem: > > > > adp1653 registers itself as a subdev, but there's no device that > > register it as its part. > > > > (ad5820 driver seems to have the same problem). > > > > Is there example "dummy" device I could use, for sole purpose of > > having these devices appear in /dev? They are on i2c, so both can work > > on their own. > > Ah, interesting. This was discussed a little bit during the Media Summit > a few weeks back: > > http://linuxtv.org/news.php?entry=2016-04-20.mchehab > > See section 5: > > "5. DT Bindings for flash & lens controllers > > There are drivers that create their MC topology using the device tree information, > which works great for entities that transport data, but how to detect entities > that don’t transport data such as flash devices, focusers, etc.? How can those be > deduced using the device tree? > > Sensor DT node add phandle to focus controller: add generic v4l binding properties > to reference such devices." > > This wasn't a problem with the original N900 since that didn't use DT AFAIK and > these devices were loaded explicitly through board code. > > But now you run into the same problem that I have. > > The solution is that sensor devices have to provide phandles to those controller > devices. And to do that you need to define bindings which is always the hard part. > > Look in Documentation/devicetree/bindings/media/video-interfaces.txt, section > "Optional endpoint properties". > > Something like: > > controllers: an array of phandles to controller devices associated with this > endpoint such as flash and lens controllers. > > Warning: I'm no DT expert, so this is just a first attempt. > > Platform drivers (omap3isp) will have to add these controller devices to the list > of subdevs to load asynchronously. I seem to have patches I haven't had time to push back then: <URL:http://salottisipuli.retiisi.org.uk/cgi-bin/gitweb.cgi?p=~sailus/linux.git;a=shortlog;h=refs/heads/leds-as3645a> This seems to be mostly in line with what has been discussed in the meeting, except that the patches add a device specific property. Please ignore the led patches in that tree for now (i.e. four patches on the top are the relevant ones here). -- Kind regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- 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
