==== Raspbian (obsolete) ====

GPIO bit-bang driver for Raspbian.

=== Kernel Config ===

Determine the running kernel and its config on the Raspberry Pi target machine.

<code>
uname -a
Linux pi3 3.12.28+ #709 PREEMPT Mon Sep 8 15:28:00 BST 2014 armv6l GNU/Linux
zgrep "* firmware as of" /usr/share/doc/raspberrypi-bootloader/changelog.Debian.gz | head -1 | awk '{ print $5 }'
53d1ae311226b5c
zcat /proc/config.gz > 53d1ae311226b5c.config
</code>

Examples.

<code>
Linux pi3 3.6.11+ #538 PREEMPT Fri Aug 30 20:42:08 BST 2013 armv6l GNU/Linux  d4f5315cfac4e
Linux pi3 3.10.23+ #608 PREEMPT Mon Dec 9 21:11:23 GMT 2013 armv6l GNU/Linux  9d34d0475f9
Linux pi3 3.10.24+ #614 PREEMPT Thu Dec 19 20:38:42 GMT 2013 armv6l GNU/Linux c32bc633039cd9
Linux pi3 3.10.25+ #622 PREEMPT Fri Jan 3 18:41:00 GMT 2014 armv6l GNU/Linux  030082b403b
Linux pi3 3.12.28+ #709 PREEMPT Mon Sep 8 15:28:00 BST 2014 armv6l GNU/Linux  53d1ae311226b5c
</code>

=== Kernel Hash ===

Determine the kernel hash for the firmware.

<code>
wget -q https://raw.github.com/raspberrypi/firmware/53d1ae311226b5c/extra/git_hash -O /tmp/hash
cat /tmp/hash 
94a382fed1a5ec303eef9e1f3439df8f759ba60c
</code>

Examples.

<code>
3.6.11+  d4f5315cfac4e   1587f775d0a3c437485262ba951afc5e30be69fa
3.10.23+ 9d34d0475f9     c15430e6a01e1332032d83f6484a866504e8ee97
3.10.24+ c32bc633039cd9  4bbea92eae6c0792e85a4ba079d367ac6aa77fb5
3.10.25+ 030082b403b     16eb921a96db3dc3555a65b53b99c15753e6b770
3.12.28+ 53d1ae311226b5c 94a382fed1a5ec303eef9e1f3439df8f759ba60c
</code>

=== Build ===

On the build host fetch the raspberry pi build tools.

<code>
mkdir -p /embedded/rpi
cd /embedded/rpi
git clone git://github.com/raspberrypi/tools.git
</code>

Fetch the kernel source for the previously determined hash.

<code>
rm -Rf /embedded/rpi/linux
cd /embedded/rpi
git clone https://github.com/raspberrypi/linux.git
cd /embedded/rpi/linux/
git checkout 94a382fed1a5ec303eef9e1f3439df8f759ba60c
git reset --hard
</code>

Prepare to build kernel and copy over configuration.

<code>
make ARCH=arm mrproper
scp pi@pi:53d1ae311226b5c.config .config
</code>

Build the kernel using the raspberry pi build tools.

<code>
make ARCH=arm oldconfig
make ARCH=arm CROSS_COMPILE=/embedded/rpi/tools/arm-bcm2708/arm-bcm2708hardfp-linux-gnueabi/bin/arm-bcm2708hardfp-linux-gnueabi- -j 8
</code>

Build the GPIO bit-bang module and copy to target machine.

<code>
hg clone http://hg.kewl.org/pub/gpio-bb
cd gpio-bb/rpi-raspbian
make 
scp ../module/src/gpio-bb.ko pi@pi:
</code>

=== Install ===

Install the module on the Raspberry Pi target machine (Eg. 3.12.28+).

<code>
mkdir -p /lib/modules/3.12.28+/kernel/local/
cp gpio-bb.ko /lib/modules/3.12.28+/kernel/local/
chown -R 0:0 /lib/modules/3.12.28+/kernel/local/
depmod -a
</code>

=== Modprobe ===

Load modules on target machine.

<code>
/etc/modprobe.d/modprobe.conf:
install gpio-bb modprobe --ignore-install gpio-bb && modprobe gpio-bb && mknod /dev/gpio-bb c 180 0
</code>

<code>
modprobe gpio-bb
</code>