BeagleBoard raw camera capture

marius.adaskevicius

Hello,

I am about to interface our custom camera board based on a Micron MT9V034 image sensor using BeagleBoard-xM. Linux root file system is based off BeagleBoard demo image (found at http://www.angstrom-distribution.org/demo/beagleboard/) and kernel version is 2.6.32. As far as I can understand, there is no native support for that particular sensor in PSP 03.00.01.06 package, although it should not be too difficult to make a custom driver by looking at the source code for other sensors. I am new to V4L2 so it is a bit difficult to understand how the whole system works. Transition from v4l2-int-device to v4l2-subdev and omap34xxcam to omap3isp makes things even worse.

Now I wonder, would it be correct to say that all sensor drivers should be written as V4L2 subdevices? If that is the case, what module is responsible for the device part (master?)? For anyone who is familiar with BeagleBoard demo image kernel configuration, are there any additional changes to be made to get raw camera capture support? After loading all the correct modules, should I get /dev/video0 interface to use in application? Would this interface be available even before connecting the camera board or it appears only after some probing is complete? Any reference or information regarding camera ISP and V4L2 would be greatly appreciated.

Marius.

over 15 years ago

0 Hristo Laftchiev over 14 years ago

Prodigy 40 points

We are doing the same.

We choose to modify an existing driver , namely mt9v022.c from the kernel in:

http://gitorious.org/beagleboard-validation/linux

The most important patches to take into account:

http://gitorious.org/beagleboard-validation/u-boot/commit/61e73503b793f042b7408ee2a43662ef3eddbba6

http://gitorious.org/beagleboard-validation/linux/commit/06ff02b8346c0ed77fabba84a1b984f53bfaecb6

http://gitorious.org/beagleboard-validation/linux/commit/da7a0c9d99ac42332cab5fcc961006a56531e1c4

http://gitorious.org/beagleboard-validation/linux/commit/6add1bee85d7cbe5c89650b1325ee345aba904cd

Also to change voltage between 1.8 and 3.3 volts - for I2c - bidirectional, for the data path camera - processor - unidirectional.

Up to now our drivers creates /dev/video0 and shows ordinary stip TV image. No more ....

0 marius.adaskevicius over 14 years ago in reply to Hristo Laftchiev

Prodigy 20 points

Hristo Laftchiev said:

We are doing the same.

We choose to modify an existing driver , namely mt9v022.c from the kernel in:

http://gitorious.org/beagleboard-validation/linux

The most important patches to take into account:

http://gitorious.org/beagleboard-validation/u-boot/commit/61e73503b793f042b7408ee2a43662ef3eddbba6

http://gitorious.org/beagleboard-validation/linux/commit/06ff02b8346c0ed77fabba84a1b984f53bfaecb6

http://gitorious.org/beagleboard-validation/linux/commit/da7a0c9d99ac42332cab5fcc961006a56531e1c4

http://gitorious.org/beagleboard-validation/linux/commit/6add1bee85d7cbe5c89650b1325ee345aba904cd

Also to change voltage between 1.8 and 3.3 volts - for I2c - bidirectional, for the data path camera - processor - unidirectional.

Up to now our drivers creates /dev/video0 and shows ordinary stip TV image. No more ....

I am sorry for the delay and thanks for sharing that information.

I started off by cloning git://gitorious.org/beagleboard-validation/linux.git beagleboardXM-camwork branch kernel where all of those patches were already applied, I believe. I then modified mt9v113 kernel driver as it was the one obviously working because of chid ip mismatch errors. I did manage to get /dev/video0 node and first few frames from a sensor using these modifications.

Unfortunately, it was really unstable because of design issues (missed the fact that all of the Beagleboard's I/O is 1.8 V). Now, as I wait for hardware revision, I have just recompiled the kernel using OpenEmbedded. I am going to make further changes to this kernel from now on as I believe this is the primary source for the kernel and all necessary patches.

What I still cannot understand is how to make v4l2-subdev work. mt9v113 driver is based off v4l2-int-device and it registers to omap34xxcam master to get a device node. I am not sure there are any benefits to use v4l2-subdev though.

Marius.

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BeagleBoard raw camera capture