Archive for February 2015

Adafruit touchscreen on a Raspberry Pi B running Slackware ARM.

I recently had the opportunity to get a friend a new Raspberry Pi Model B. I really like these, I have several all running Slackware ARM. While I have tried other distros, I find myself always going back to Slackware after a while for one reason or another, but that is a talk for another day. My friend decided he wanted to run Slackware on one of his Raspberry Pis, so I helped him out and get everything installed. Then I was presented with another issue. He wanted to use his Adafruit touchscreen. Now, Adafruit’s documentation and setup guides are really good, but only if you are running Raspbian (or a Debian based system). So that did present an issue, but one I wanted to solve.

Before I continue, please note that I did get this working (video and images at the bottom of the post), but I had to deliver the Pi back before I got a change to try again from scratch. This guide is based heavily off my best recollection of the steps I took, and may not be complete. If I’m missing something, or you can’t get it to work, let me know and I will try to help… or send me a screen so I can do this again.

Start with checking out this guide: https://learn.adafruit.com/adafruit-pitft-28-inch-resistive-touchscreen-display-raspberry-pi/software-installation it was helpful in getting everything going.

Now, download all the needed files:

wget http://adafruit-download.s3.amazonaws.com/libraspberrypi-bin-adafruit.deb
wget http://adafruit-download.s3.amazonaws.com/libraspberrypi-dev-adafruit.deb
wget http://adafruit-download.s3.amazonaws.com/libraspberrypi-doc-adafruit.deb
wget http://adafruit-download.s3.amazonaws.com/libraspberrypi0-adafruit.deb
wget http://adafruit-download.s3.amazonaws.com/raspberrypi-bootloader-adafruit-20140917-1.deb

Download and install deb2tgz (https://code.google.com/p/deb2tgz/). This will help you convert those deb files to tgz for Slackware.

Now convert those deb files to tgz (deb2tgz *.deb)

Then install (installpkg *.tgz)

Now, you need to make a copy of raspberrypi-bootloader-adafruit-20140917-1.deb and place it in another directory. Once there, run:

ar x raspberrypi-bootloader-adafruit-20140917-1.deb

This will explode out the archive. Find the file called data.tar.gz, and run:

tar -zxf data.tar.gz

Now there will be some new directories. One is called boot. Make a backup of you /boot directory, then copy everything in that new boot to /boot.

cp -r /boot /boot.bak
cd boot
cp * /boot

This will install the correct kernel that you need to use.

Next, open /boot/config.txt. The only line you need is gpu_mem=32.

Now, there are a few more packages you need to install. First is called evtest. I found an awesome slackbuild repository located over at https://github.com/PhantomX/slackbuilds.git, and we are going to install his evtest package.

git clone https://github.com/PhantomX/slackbuilds.git
cd slackbuilds/
cd evtest/
./evtest.SlackBuild 
installpkg evtest-1.32-x86_64-1root.txz

Notice how the arch listed in the Slackware package as x86_64, don’t worry, it works, just install it.

Next is tslib. Here is how I built and installed it (also, I cheated and did not build a Slackware package).

wget http://ftp.de.debian.org/debian/pool/main/t/tslib/tslib_1.0.orig.tar.gz
tar -zxf tslib_1.0.orig.tar.gz 
cd tslib-1.0/
./autogen.sh 
./configure
make
make install

Last, we need to build a package called xf86-video-fbturbo. (Forgive me, you may not need to run make in that first directory, but definitely in the src directory)

git clone https://github.com/ssvb/xf86-video-fbturbo
cd xf86-video-fbturbo/
./autogen.sh 
make
cd src
autoreconf -vi
./configure --prefix=/usr
nano xorg.conf 
make
make install

There, that was fun! Alright, lets edit a few more files.

Open /boot/cmdline.txt, and place this one line in there (it is the only line for me, you maybe different)

dwc_otg.lpm_enable=0 console=tty1 nofont root=/dev/mmcblk0p3 fbcon=map:10 fbcon=font:VGA8x8 rootfstype=ext4 rootwait ro

Then open /etc/X11/xorg.conf.d/99-calibration.conf (if the directory or file does not exist, create it!) and place this in the file.
Note the commented out items, I meant to experiment with them, I don’t remember if those options break anything, but I doubt it.

Section "InputClass"
    Identifier "calibration"
    MatchProduct "stmpe-ts"
    Option "Calibration" "3800 200 200 3800"
    Option "SwapAxes" "1"
EndSection
 
Section "Device"
        Identifier      "Allwinner A10/A13 FBDEV"
        Driver          "fbturbo"
        Option          "fbdev" "/dev/fb1"
#        Option          "SwapbuffersWait" "true"
        # `man fbturbo` to know more options
#        Option          "AccelMethod" "G2D"
EndSection
 
Section "Monitor"
    Identifier "Monitor0"
    Option "DPMS"
EndSection
 
Section "Screen"
    Identifier "Screen0"
    Device     "main"
    Monitor    "Monitor0"
    DefaultDepth 16
    SubSection "Display"
            Depth 16
            Modes "320x240"
    EndSubSection
EndSection

Lastly, open /etc/rc.d/rc.local and add these lines:

modprobe spi-bcm2708
modprobe fbtft_device name=adafruitrt28 rotate=90 frequency=32000000
export FRAMEBUFFER=/dev/fb1

I also recommend adding the export framebuffer to your user’s ~/.bashrc file. You need that before X will start.

I really hope I got this all right. Feel free to complain. Maybe I’ll get another chance to play with this again in the near future, and this time, I’ll get it right! I wish you all the best of luck! Cheers,

IMG_20150206_224415IMG_20150206_224423

If the video above isn’t loading, you can view it here: https://www.youtube.com/watch?v=KpzBYshxY9c