em28xx procedure

This is my em28xx procedure to get a working capture device running on a raspberry pi from an empty SD card. It is a bit crude - but it worked for me. These notes are primarily for my own benefit, so may not be as thorough as they could be... I presume there must be an easier way to build the em28xx driver without building everything each time, but this worked. I have presently dropped the RPi in favour of the BeagleBone, which doesn't seem to have any USB issues with larger image sizes. You won't see any sudo commands, other than building the wheezy image on the mac, as I log in as root on the raspberry pi

Make the disk image (mac)

diskutil list

sudo diskutil unmountDisk /dev/disk1

dd if=/Users/michael/Desktop/RaspberryPi/Images/2012-06-18-wheezy-beta.img of=/dev/disk1 bs=1m

boot the pi with new card

apt-get update && apt-get upgrade

apt-get install git ffmpeg motion libncurses5-dev

Rebuild the kernel

see;

http://elinux.org/RPi_Kernel_Compilation

git clone --depth 1 https://github.com/raspberrypi/linux.git

cd linux

zcat /proc/config.gz > .config

make menuconfig

(enable i2c and em28xx stuff)

make

git clone https://github.com/raspberrypi/tools
cd tools/mkimage/
python imagetool-uncompressed.py home/pi/linux/arch/arm/boot/Image

mv /boot/kernel.img /boot/kernel.old


cp kernel.img /boot/kernel.img

cd /home/pi/linux

make modules_install

reboot

update em28xx drivers

sudo apt-get install  patchutils libproc-processtable-perl

git clone git://linuxtv.org/media_build.git

cd media_build

./build

./build downloads the latest everything and tries to make it - if this works, that's great, but we need to edit em28xx-core.c and remake this. The sed command below changes height >>= norm_maxh(dev)to height = norm_maxh(dev) >> 1 in /linux/drivers/media/video/em28xx/em28xx-core.c to solve a portability issue to ARM. (Makarov, 2012)

cd linux/drivers/media/video/em28xx/

sed -i 's/height >>= norm_maxh(dev)/height = norm_maxh(dev) >> 1/' em28xx-core.c

Now build the drivers again. This time using make all instead of ./build to preserve changes to em28xx-core.c


cd media_build

make all    


make install

Note, Trying to repeat this process on another SD card has invoked an error during the ./build stage;

/home/pi/media_build/v4l/drxk_hard.c:333:3: error: implicit declaration of function '__i2c_transfer' [-Werror=implicit-function-declaration]

I'm not sure what I have done differently - but I ran make menuconfig in the media_build directory and removed any modules that 'didn't look very useful' and that fixed it.

Don't forget to edit /etc/motion/motion.conf

cd /etc/motion/motion.conf


cp motion.conf motion.conf.original


nano motion.conf

Input should be input 1 or input 0 depending on the device - if you get it wrong, and the device is working you will see a black screen (not green!). I would recommend the resolution is 320x240 for the first run. Turn on interlacing (ffmpeg_deinterlace on) and webserver (webcam_localhost off), you will probably want webconfig too (control_localhost off)... you know all this stuff. Here are some sed commands I might use next time I do this, because it's getting boring;

sed -i 's/input 8/input 0/' motion.conf


sed -i 's/ffmpeg_deinterlace off/ffmpeg_deinterlace on/' motion.conf


sed -i 's/webcam_localhost on/webcam_localhost off/' motion.conf


sed -i 's/control_localhost on/control_localhost off/' motion.conf


Then test it

motion

References

Vitaly Makarov (2011) Non-portable code in em28XX driver, available from http://www.digipedia.pl/usenet/thread/18550/7691/ , accessed 21/7/12