Hi Laurent, On 10/10/2012 03:25 PM, Laurent Pinchart wrote: > On Tuesday 09 October 2012 13:00:24 Hans Verkuil wrote: >> On Tue 9 October 2012 12:34:48 Sylwester Nawrocki wrote: >>> On 10/08/2012 11:40 AM, Guennadi Liakhovetski wrote: >>>> On Fri, 5 Oct 2012, Sylwester Nawrocki wrote: >>>>> I would really like to see more than one user until we add any core >>>>> code. No that it couldn't be changed afterwards, but it would be nice >>>>> to ensure the concepts are right and proven in real life. >>>> >>>> Unfortunately I don't have any more systems on which I could easily >>>> enough try this. I've got a beagleboard with a camera, but I don't think >>>> I'm a particularly good candidate for implementing DT support for OMAP3 >>>> camera drivers;-) Apart from that I've only got soc-camera based >>>> systems, of which none are _really_ DT-ready... At best I could try an >>>> i.MX31 based board, but that doesn't have a very well developed .dts and >>>> that would be soc-camera too anyway. >>> >>> I certainly wouldn't expect you would do all the job. I mean it would be >>> good to possibly have some other developers adding device tree support >>> based on that new bindings and new infrastructure related to them. > > As I mentioned in another e-mail, I plan to work on DT support for the OMAP3 > ISP, but I first need generic clock framework support for OMAP3.
OK, let's hope it's available soon. >>> There have been recently some progress in device tree support for Exynos >>> SoCs, including common clock framework support and we hope to add FDT >>> support to the Samsung SoC camera devices during this kernel cycle, based >>> on the newly designed media bindings. This is going to be a second >>> attempt, after our initial RFC from May [1]. It would still be SoC >>> specific implementation, but not soc-camera based. >>> >>> I wasn't a big fan of this asynchronous sub-devices probing, but it now >>> seems to be a most complete solution to me. I think it just need to be >>> done right at the v4l2-core so individual drivers don't get complicated >>> too much. >> >> After investigating this some more I think I agree with that. There are some >> things where we should probably ask for advice from the i2c subsystem devs, >> I'm thinking of putting the driver back into the deferred-probe state in >> particular. > > We might actually not need that, it might be easier to handle the circular > dependency problem from the other end. We could add a way (ioctl, sysfs, ...) > to force a V4L2 bridge driver to release its subdevs. Once done, the subdev > driver could be unloaded and/or the subdev device unregistered, which would > release the resources used by the subdev, such as clocks. The bridge driver > could then be unregistered. That sounds like an option. Perhaps it could be done by v4l2-core, e.g. a sysfs entry could be registered for a media or video device if driver requests it. I'm not sure if we should allow subdevs in "released" state, perhaps it's better to just unregister subdevs entirely right away ? >> Creating v4l2-core support for this is crucial as it is quite complex and >> without core support this is going to be a nightmare for drivers. -- Regards, Sylwester _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss