gpio.pl will lookup kernel's view of pinouts on different boards (useful for device tree and gpio debugging)
To install dependencies, run debian-install.sh
It needs root privileges, and generates wide aligned output, so it's probably best to run it like this:
sudo ./gpio.pl | less -S
Layout of pins is described using files in pins directory. File used is determined on the
runtime device tree name found in /proc/device-tree/model with optional .txt extension.
Filenames can be just beginning of this value to support mutiple models with same file.
Lines starting with # are regex to select pinout based on /proc/device-tree/model and it will
not be included in output. Good example is pins/Raspberry Pi.txt which
defines pinouts of all Rasperry Pis without duplication.
Lines with ## are descriptions or comments (name of header, for example) which will be included
in output.
One or two row pin headers (separated by a tab) are supported, and 2.54mm pin spacing is assumed.
First value (separated by spaces) specifies the name of pin as shown on board, while the second
value specifies kernel gpio (eg. gpio 42) and an optional description, usually in round brackets.
It can include additional spaces, but not tabs, since a tab specifies second column.
--pinmux flag will include kernel's view of available pin muxing confiration
in curly braces {}. This is useful to find pins which are interrupt capable.
--alt flag will use round braces () data from pins file and raspi-gpio funcs to produce
readable possible pin configurations.
To support breakout boards with different pinouts, you can use --pins argument:
sudo ./gpio.pl --pins pins/Raspberry\ Pi-Extension\ Board.txt
It will dump a lot of output to STDERR which can also be useful for debugging or examining kernel's
view of your system.
gpio.pl tool will also create SVG pinouts if you invoke it with --svg argumet. Output will have
correct 2.54mm spacing so you can put it on your board to make wiring it up easier:
sudo ./gpio.pl --svg pins/Raspberry\ Pi.txt > /tmp/rpi.svg
For device tree information, best source right now is this presentation: https://elinux.org/images/d/dc/Elce_2017_dt_bof.pdf
device-tree directory contains example device trees.
To load them on runtime, use overlay-load.sh like this:
vi device-tree/gpio-leds.dts
armbian-add-overlay device-tree/gpio-led.dts
dmesg -w &
./overlay-load.sh /boot/overlay-user/gpio-led.dtbo
If you are not using armbian, you can also specify dts file which will compile it for you:
pi@pihdmi:~/linux-gpio-pinout/device-tree $ sudo ../overlay-load.sh rpi_control_board.dts
To load kernel module for i2c sensors without writing device tree
echo module_name address into i2c bus:
echo lm75 0x49 > /sys/bus/i2c/devices/i2c-1/new_device
i2c-userspace contains random i2c userspace device drivers
i2c-tracing.sh is script which shows example how to use i2c tracing. This
is software-only alternative to logic analyzer if you are debugging i2c
communication.
For overlay to work on 4.17 kernels you need recent dtc compiler from:
git clone https://git.kernel.org/pub/scm/utils/dtc/dtc.git
which in turn needs bison and flex to compile:
apt-get install bison flex
type make to compile it and create symlink to it:
dpavlin@cubieboard2:~/linux-gpio-pinout/dtc$ sudo ln -sfv `pwd`/dtc /lib/modules/$(uname -r)/build/scripts/dtc/dtc
For 64-bit sunxi (like Pine64) sunxi-tools doesn't show all ports (up to PL), so I included script to compile it from source with a fix:
dpavlin@pine64:~/linux-gpio-pinout$ ./sunxi-tools-sunxi64-install.sh