Re: i.mx6 camera interface (CSI) and mainline kernel

[Steve Longerbeam <steve_longerbeam@mentor.com>]

Hi Philippe,

On 03/03/2016 12:36 AM, Philippe De Muyter wrote:
>
> Just to be sure : do you mean  https://github.com/slongerbeam/mediatree.git
> or something else ?

Sorry, yes I meant https://github.com/slongerbeam/mediatree.git.

>
>>> So far I have retested video capture with the SabreAuto/ADV7180 and
>>> the SabreSD/OV5640-mipi-csi2, and video capture is working fine on
>>> those platforms.
>>>
>>> There is also a mem2mem that should work fine, but haven't tested yet.
>>>
>>> I removed camera preview support. At Mentor Graphics we have made
>>> quite a few changes to ipu-v3 driver to allow camera preview to initialize
>>> and control an overlay display plane independently of imx-drm, by adding
>>> a subsystem independent ipu-plane sub-unit. Note we also have a video
>>> output overlay driver that also makes use of ipu-plane. But those changes are
>>> extensive and touch imx-drm as well as ipu-v3, so I am leaving camera preview
>>> and the output overlay driver out (in fact, camera preview is not of much
>>> utility so I probably won't bring it back in upstream version).
>>>
>>> The video capture driver is not quite ready for upstream review yet. It still:
>>>
>>> - uses the old cropping APIs but should move forward to selection APIs.
>>>
>>> - uses custom sensor subdev drivers for ADV7180 and OV564x. Still
>>>   need to switch to upstream subdevs.
> Is it only a problem of those sensor drivers (which exact files ?) or
> is it a problem of the capture driver itself ?

The camera interface driver (drivers/staging/media/imx6/capture/mx6-camif.c)
is binding to these subdevs:

drivers/staging/media/imx6/capture/adv7180.c
drivers/staging/media/imx6/capture/ov5642.c
drivers/staging/media/imx6/capture/ov5640-mipi.c

But instead should use the subdevs under drivers/media/i2c, specifically:

drivers/media/i2c/adv7180.c (and adding whatever standard subdev features
the imx6 interface driver requires).

There is a drivers/media/i2c/soc_camera/ov5642.c, but there is no mipi-csi2
capable subdev for the ov5640 with the mipi-csi2 interface, so that would have
to be created.



> I must update a sensor driver I wrote for the intdev interface found
> in the freescale kernel, and I'd like to start from a working subdev
> example.  Which driver should I choose as an example ?

There's lots of good examples under drivers/media/i2c/.


Steve