Skip to content

lgpio.md

Latest commit

 

History

History
126 lines (94 loc) · 3.19 KB

lgpio.md

File metadata and controls

126 lines (94 loc) · 3.19 KB
Raw

lgpio — header GPIO tool

Translates Libre Computer header pins (and RPi BCM numbers) to gpiod chip/line, sysfs, SoC name, pad, schematic ref, and mux description. Interactive get/set/watch for debugging — not a high-performance API (lookup cost is non-trivial).

Package: libretech-gpio (depends on gpiod).
Data: libre-computer/<board>/gpio.map (see gpio-map.md).

Board detection

Uses DMI:

  • /sys/class/dmi/id/board_vendor → VENDOR (e.g. libre-computer)
  • /sys/class/dmi/id/board_name → BOARD (e.g. aml-s905x-cc)

Override for host-side use:

export VENDOR=libre-computer BOARD=aml-s905x-cc
./lgpio headers

Commands

lgpio headers
lgpio header [HEADER]
lgpio info [HEADER] PIN [type=all,gpiod,chip,line,sysfs,name,pad,ref,desc]
lgpio get [HEADER] PIN
lgpio set [options] [HEADER_]PIN={0,1} ...
lgpio pinmux [HEADER] [PIN]
lgpio watch [options] [HEADER] PIN
lgpio bcm [PIN] [type=...]
lgpio bcm check
lgpio debug [BANK][_NUM]    # board-specific, needs gpio.config + memtool

headers / header

List header names, or dump all rows for one header (e.g. 7J1).

info

Default header is the first data row in gpio.map (usually the 40-pin header). Types: all, gpiod (chip+line), chip, line, sysfs, name, pad, ref, desc.

lgpio info 7J1 19
lgpio info 19 name
lgpio info 24 gpiod

pinmux

Print pad + alternate functions from the Ref / Desc columns (mux options as A | B | C).

lgpio pinmux 7J1 19
lgpio pinmux 7J1          # entire header

get / set

lgpio get 7J1 11
lgpio set 7J1_11=1
lgpio set 11=0            # default header

# Bias / drive / active-low (libgpiod v1 and v2)
lgpio set -b pull-up 11=1
lgpio set -d open-drain -l 22=0
lgpio set --bias pull-down --drive push-pull 7J1_12=1
Option Values
-l / --active-low treat line as active-low
-b / --bias pull-up, pull-down, disabled, as-is
-d / --drive push-pull, open-drain, open-source

Note: On libgpiod v2, line state after gpioset exits is not guaranteed unless held; lgpio set uses a short hold period for one-shot values. Do not use get/set as a tight control loop.

watch

Edge monitoring via gpiomon (install gpiod).

lgpio watch 22
lgpio watch -e falling -b pull-up 7J1 22
lgpio watch -n 10 11      # exit after 10 events
Option Meaning
-e / --edges rising, falling, both (default)
-b / --bias pull-up / pull-down / disabled
-l / --active-low invert edge sense
-n / --num-events exit after N events

bcm

RPi BCM GPIO number → physical pin on the default header, then info.

lgpio bcm 8 name          # BCM8 → pin 24 → SoC name
lgpio bcm 2 sysfs
lgpio bcm check           # full coverage table + WARNINGs if incomplete

bcm check flags: missing map rows, non-GPIO (power) pins, incomplete alias coverage (SDA0 / SCL0 / ID_SD / ID_SC).

Related