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

[Steve Longerbeam <steve_longerbeam@mentor.com>]

On 03/07/2016 08:19 AM, Tim Harvey wrote:
> On Thu, Mar 3, 2016 at 9:45 AM, Steve Longerbeam
> <steve_longerbeam@mentor.com> wrote:
>> 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.
>>
> Steve,
>
> I've built your mx6-media-staging branch and added device-tree config
> for the Gateworks Ventana boards which have an on-board ADV7180 and it
> works great. I've tested it capturing frames via v4l2-ctl as well as
> gstreamer.
>
> Please let me know what kind of testing you need. I would love to see
> this get mainlined!
>


Hi Tim, good to hear it works for you on the Ventana boards.

I've just pushed some more commits to the mx6-media-staging branch that
get the drivers/media/i2c/adv7180.c subdev working with the imx6 capture
backend. Images look perfect when switching to UYVY8_2X8 mbus code instead
of YUYV8_2X8. But I'm holding off on that change because this subdev is used
by Renesas targets and would likely corrupt captured images for those
targets. But I believe UYVY is the correct transmit order according to the
BT.656 standard.

Another thing that should also be changed in drivers/media/i2c/adv7180.c
is the field type. It should be V4L2_FIELD_SEQ_TB for NTSC and V4L2_FIELD_SEQ_BT
for PAL.

Steve