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

Steve Longerbeam
2016-06-02T16:50:40Z

On 06/02/2016 06:55 AM, Hans Verkuil wrote:
>
> On 06/02/2016 03:29 PM, Tim Harvey wrote:
>> On Wed, Mar 9, 2016 at 4:12 PM, Steve Longerbeam
>> <steve_longerbeam@mentor.com> wrote:
>>> On 03/09/2016 02:44 PM, Tim Harvey wrote:
>>>> On Tue, Mar 8, 2016 at 6:06 PM, Steve Longerbeam
>>>> <steve_longerbeam@mentor.com> wrote:
>>>>> On 03/07/2016 08:19 AM, Tim Harvey wrote:
>>>> <snip>
>>>>> 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
>>>>>
>>>>>
>>>> Steve,
>>>>
>>>> with your latest patches, I'm crashing with an null-pointer-deref in
>>>> adv7180_set_pad_format. What is your kernel config for
>>>> CONFIG_MEDIA_CONTROLLER and CONFIG_VIDEO_V4L2_SUBDEV_API?
>>> Right, I thought I fixed that, I was passing a NULL pad_cfg for
>>> TRY_FORMAT, but that was fixed. Maybe you fetched a version
>>> of mx6-media-staging while I was in the middle of debugging?
>>> Try fetching again.
>>>
>>> I tried with both CONFIG_MEDIA_CONTROLLER and
>>> CONFIG_VIDEO_V4L2_SUBDEV_API enabled and both disabled, and
>>> I don't get the null deref in adv7180_set_pad_format.
>>>
>>>
>>>> Your tree contains about 16 or so patches on top of linux-media for
>>>> imx6 capture. Are you close to the point where you will be posting a
>>>> patch series? If so, please CC me for testing with the adv7180 sensor.
>>> I guess I can try posting a series again, but there will likely be push-back from
>>> Pengutronix. They have their own video capture driver for imx6. Last I heard (a while ago!)
>>> their version did not implement scaling, colorspace conversion, or image rotation via
>>> the IC. Instead their driver sends raw camera frames directly to memory, and image
>>> conversion is carried out by separate mem2mem device. Our capture driver does
>>> image conversion (scaling, CSC, and rotation) natively using the IC pre-processing channel.
>>> We also have a mem2mem device that does conversion using IC post-processing,
>>> which I have included in mx6-media-staging.
>>>
>>> Also IIRC they did some pretty slick stuff with a video bus multiplexer subdev, which
>>> can multiplex video from different sensors either using the internal mux in the SoC,
>>> or can control an external mux via gpio. Our driver only supports the internal mux,
>>> and does it with a platform data function.
>>>
>>> But like I said, I don't what the latest status is of the Pengutronix video capture support.
>>>
>>> Btw, I just pushed an update of mx6-media-staging that implements vidioc_[gs]_selection.
>>>
>>> Steve
>>>
>>>
>> Steve,
>>
>> Some time has passed without any IMX6 CSI drivers or response from
>> Pengutronix and Hans has agreed to add either/both drivers to staging.
>> Do you have time to rebase and re-post your driver(s)? Maybe that will
>> get the ball rolling on this final huge missing feature for the IMX6
>> in mainline.
> Right. All that is needed is for someone to take the latest version, make it compile
> in the media_tree in drivers/media/staging and post the patch (just take care to keep
> the correct copyrights, Signed-off-by's etc.) and I'll be happy to take it. This is
> exactly what staging is for. I think it will greatly increases the chances of this
> code being improved for mainline. And I'm happy to take both drivers as well, again,
> that's what staging is for.
>
> I've been thinking of doing this myself, but I just don't have the time.
>
> Ideally this is done by the authors, but if they don't have time either then someone
> else can do this.
>

Hi Hans and Tim,

No problem, I will repost the patch-set this week. I've been meaning to,
just busy lately with other tasks.

Steve