Hi Laurent,
> Hi Daniel,
>
> On Thursday 26 May 2011 15:06:17 Daniel Lundborg wrote:
> > > On Thursday 26 May 2011 10:57:39 Daniel Lundborg wrote:
> > > > Hello,
> > > >
> > > > I am developing a camera sensor driver for the Aptina MT9V034. I
> > > > am only using it in snapshot mode and I can successfully trigger
> > > > the sensor and receive pictures using the latest omap3isp driver
> > > > from git://linuxtv.org/pinchartl/media.git branch
> > > > omap3isp-next-sensors with kernel 2.6.38.
> > > >
> > > > I configure the sensor with media-ctl:
> > > >
> > > > media-ctl -r -l '"mt9v034 3-0048":0->"OMAP3 ISP CCDC":0[1],
"OMAP3
> > > > ISP
> > > > CCDC":1->"OMAP3 ISP CCDC output":0[1]'
> > > >
> > > > media-ctl -f '"mt9v034 3-0048":0[SGRBG10 752x480], "OMAP3 ISP
> > > > CCDC":1[SGRBG10 752x480]'
> > > >
> > > > And take pictures with yavta:
> > > >
> > > > ./yavta -f SGRBG10 -s 752x480 -n 6 --capture=6 -F /dev/video2
> > > >
> > > > My trouble is that I am always receiving whiter pictures when I
> > > > wait a moment before triggering the sensor to take a picture. If
I
> > > > take several pictures in a row with for instance 20 ms between
> > > > them, they all look ok. But if I wait for 100 ms the picture
will get much whiter.
> > > >
> > > > I have turned off auto exposure and auto gain in the sensor and
> > > > the LED_OUT signal always have the same length (in this case 8
msec).
> > >
> > > I assume you've measured it with a scope ?
> > >
> > > Try disabling black level calibration and row noise correction as
well.
> > > Please also double-check that AEC and AGC are disabled. I've had a
> > > similar issue with an MT9V032 sensor, where a bug in the driver
> > > enabled AEC/AGC instead of disabling them.
> >
> > The register on 0xaf (MT9V034_AGC_AEC_ENABLE) is set to 0 and is 0
> > when I read from it.
> > bit 0 - AEC enable context A, bit 1 - AGC enable context A, bit 8 -
> > AEC enable context B, bit 9 - AGC enable context B
> >
> > The register on 0x47 (MT9V034_BL_CALIB_CTRL) is set to 0 and is 0
when
> > I read from it.
> > bit 0 - (1 = override with programmed values, 0 = normal operation),
> > bit
> > 7:5 - Frames to average over
>
> If I'm not mistaken "normal operation" means that automatic black
level calibration is enabled. Try to set bit 0 to 1 to override the
automatic algorithm (and program a zero value in register 0x48).
This did not work unfortunately.. :( I have solved this by always taking
2 pictures and ignoring the first of them...
>
> > The register on 0x70 (MT9V034_ROW_NOISE_CORR_CONTROL) is set to 0
and
> > is 0 when I read from it.
> > bit 0 - enable noise correction context A , bit 1 - Use black level
> > avg context A, bit 8 - enable noise correction context B, bit 9 -
Use
> > black level avg context B
> >
> > I measure the signals with a scope and the LED_OUT signal is always
8
> > msec when triggered.
> >
> > Code from my mt9v034.c:
>
> [snip]
>
> > And from my board-overo.c file:
> >
> > void overo_camera_configure(struct v4l2_subdev *subdev) {
> > struct isp_device *isp =
> > v4l2_dev_to_isp_device(subdev->v4l2_dev);
> >
> > isp_reg_clr_set(isp, OMAP3_ISP_IOMEM_MAIN, ISP_TCTRL_CTRL,
> > ~0x9a1b63ff, 0x98036000); // Set CAM_GLOBAL_RESET pin as output,
> > enable shutter, set DIVC = 216
> > isp_reg_clr(isp, OMAP3_ISP_IOMEM_MAIN, ISP_TCTRL_SHUT_DELAY,
> > 0x01ffffff); // Set no shutter delay
> > isp_reg_clr_set(isp, OMAP3_ISP_IOMEM_MAIN, ISP_TCTRL_SHUT_LENGTH,
> > 0x01ffffff, 0x000003e8); // Set shutter signal length to 1000 (=>
1000
> > * 1/216MHz * 216 = 1 ms)
> > isp_reg_clr_set(isp, OMAP3_ISP_IOMEM_MAIN,
ISP_TCTRL_GRESET_LENGTH,
> > 0x01ffffff, 0x000003e8); // Set CAM_GLOBAL_RESET signal length to
1000
> > (=> 1000 * 1/216MHz * 216 = 1 ms) }
> >
> > static void overo_camera_take_picture(struct v4l2_subdev *subdev) {
> > struct isp_device *isp =
> > v4l2_dev_to_isp_device(subdev->v4l2_dev);
> >
> > isp_reg_clr_set(isp, OMAP3_ISP_IOMEM_MAIN, ISP_TCTRL_CTRL, 0,
> > 0x00e00000); // Enable shutter (SHUTEN bit = 1)
> > isp_reg_clr_set(isp, OMAP3_ISP_IOMEM_MAIN, ISP_TCTRL_CTRL, 0,
> > 0x20000000); // Start generation of CAM_GLOBAL_RESET signal
(GRESETEN
> > bit = 1) }
>
> I'll have to implement support for that in the OMAP3 ISP driver at
some point.
>
> [snip]
>
> > > Do you have a light source connected to the LED_OUT signal ? If
so,
> > > can you try disabling it and using a constant light source ?
> >
> > No I'm not using the LED_OUT signal other than measuring the
exposure
> > time at this point.
> >
> > > > Why would the pictures become whiter if I wait a moment before
> > > > taking a picture?
> > > >
> > > > If I set the sensor in streaming mode all pictures look like
they
> > > > should.
> > > >
> > > > Could there be something with the H3A auto white balance or auto
> > > > exposure?
> > >
> > > The OMAP3 ISP isn't able to apply any H3A algorithm to the images
by
> > > itself. The H3A hardware support only computes statistics, and a
> > > userspace application then needs to compute parameters (such as
> > > exposure time and
> > > gains) based on the statistics, and apply them to the hardware. As
> > > yavta doesn't include H3A algorithms, the differences in picture
> > > brightness can only come from the sensor.
>
> --
> Regards,
>
> Laurent Pinchart
Thanks,
Daniel Lundborg
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