Numbering and Detection

Numbering and Detection

Public numbering modes

Mode	Meaning
GPIO.BOARD	Physical connector position on the exact supported carrier/header.
GPIO.BCM	Compatibility identifier from the board map. It is not necessarily the SoC's native GPIO line.

Internally, the backend also needs the native SoC GPIO bank/line or Linux gpiochip offset. Do not expose or document that controller identifier as though it were universally interchangeable with GPIO.BCM.

Board detection

Detection aliases and Banana Pi model selection are maintained in source/c_gpio_bpi.c. Board-specific maps are included through source/bpi_gpio.h and the relevant source/bpi-*.h headers.

For a new board, collect both values from the exact production image:

cat /proc/device-tree/model; echo
tr '\0' '\n' < /proc/device-tree/compatible

Prefer exact compatible strings over broad marketing names. Generic model strings shared by multiple revisions must not silently select the wrong carrier map.

Modules and carriers

A compute module does not define a 26/40-pin user header by itself. GPIO.BOARD can only be promised for the exact carrier/development kit.

Examples:

• LM7 uses W3 as its documented development kit.
• CM4, CM5, CM5 Pro, CM6, AIM7 and AI2N support claims must name the exact IO board/carrier.

Detection bug report data

Attach:

uname -a
cat /etc/os-release
cat /proc/device-tree/model; echo
tr '\0' '\n' < /proc/device-tree/compatible
python3 -c 'import RPi.GPIO as GPIO; print(GPIO.VERSION); print(GPIO.RPI_INFO)'

Also provide board, module and carrier revisions and a clear header photograph.