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V4l2 video0

Question asked by samiksha on Mar 13, 2012
Latest reply on Mar 18, 2012 by ScottJiang

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Hello,

I have the following hardware setup:

cm-bf561, evaluation kit and camera extender board from bluetechnix. camera: ov7670 and ov2640

Software setup:

uclinux distribution: 2011R1-RC3.

menuconfig set up as per http://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:drivers:v4l2_blackfin_capture

Did settings as per the above link for ov2640

Problem:

No video0 device is created after modprobe bfin-video-capture

How should I get the v4l2 to work and grab an image?

Also I tried to port v4l1 from 2010 distribution, but that gives a memory exception while trying to grab an image.

Is the v4l previous framework compatible with the new kernel?

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sonic Mar 13, 2012 10:52 PM
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ovXXXX sensors are not enabled and tested in Blackfin Linux kernel. If you want to use them, you should add proper ovXXXX bfin_capture platform data into your cm-bf561 board file by your self.
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samiksha @ sonic on Mar 14, 2012 10:49 AM
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Thank you for your answer.
Could you please help me as to how I can do that or if there is an example that I can follow?
Also do you know if V4L1 will be compatible on the new kernel? I have replaced the complete video folder in the drivers/media under the linux kernel tree and compiled the code but when I try to grab an image, it gives me memory errors such as the following:

Stack info:
SP: [0x020abf24] IM `;1
Memory from 0x020abf20 to 020ac000
020abf20: 025fff70 [0254ceb0] 00008000 00000000 00000000 020ac000 0254ceb0 0254ceb0
020abf40: 02082840 001098ec 02003004 0255da6d 0258c5bf 0255da22 0258c5be 00000000
020abf60: 00000000 00000083 00000000 00000083 00000000 00000000 7ffff000 000000c0
020abf80: 00000137 00000000 00000000 00000000 00000000 0000005b 00001802 00000001
020abfa0: fffffffc 00000006 00000003 02082990 02082918 025ffc9c 025ffca8 0253d188
020abfc0: 025b75b8 0253d188 025b7294 0254cea4 00000036 025fff9d 025fff50 025fff70
020abfe0: 00000001 0000cea4 025ffcd8 803c7601 00000003 00000003 00000036 00000006
Return addresses in stack:
Modules linked in: blackfin_cam videodev v4l1_compat ov7673
Kernel panic - not syncing: Kernel exception
Stack info:
SP: [0x020abcf4]
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sonic @ samiksha on Mar 15, 2012 3:04 AM
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Please refer to linux-kernel/arch/blackfin/mach-bf561/board/ezkit.c
Search BLACKFIN_CAPTURE.
You should match platform data with your hardware design.
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ScottJiang @ sonic on Mar 16, 2012 4:00 AM
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V4L1 has been removed from the new kernel. You can refer to drivers/media/video/vs6624.c as an example sensor driver.
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samiksha @ ScottJiang on Mar 16, 2012 6:14 AM
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Thank you everyone for your answers.
I have tried to understand the ezkit.c but the parameters related to adv7183 that are present, I am not sure I understand what they are for.
static struct v4l2_input adv7183_inputs[] = {
static struct bcap_route adv7183_routes[] = {
what are these structures used for?
Is there a similar configuration for ovXX series present somewhere that I can go through?

I also tried to follow the vsXX series but that is not supported in the ezkit.c so I am guessing, it will anyway not work
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ScottJiang @ samiksha on Mar 16, 2012 6:26 AM
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ezkit.c is a board file where you pass some board specific parameters to the driver. adv7183.c is the real driver but it is a decoder driver. vs6624.c is a sensor driver which is similar to ov sensors.
adv7183_input is the input array adv7183 can support. adv7183_routes is the route of each input.
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samiksha @ ScottJiang on Mar 16, 2012 7:19 AM
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Thank you for your reply.
So do I need to add anything related to the sensor in the ezkit.c.
If yes, then what is it that I need to add, in order to make it work
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ScottJiang @ samiksha on Mar 18, 2012 11:21 PM
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Considering you are talking about ov sensors, I have to say I can't tell you details. What you need to do is to write an ov sensor driver and pass in parameters that are requested in your driver. Please refer to Documentation/video4linux/v4l2-framework.txt as a start.
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