# Manage the GPIO lines from command line with gpiod gpiod is a set of tools for interacting with the linux GPIO character device that uses libgpiod library. Since linux 4.8 the GPIO sysfs interface is deprecated. User space should use the character device instead. libgpiod encapsulates the ioctl calls and data structures behind a straightforward API. If you are using Debian Buster 10 install gpiod by typing these commands: sudo apt update sudo apt install gpiod Six command-line tools are available: * gpiodetect - list all gpiochips present on the system, their names, labels and number of GPIO lines * gpioinfo - list all lines of specified gpiochips, their names, consumers, direction, active state and additional flags * gpioget - read values of specified GPIO lines * gpioset - set values of specified GPIO lines, potentially keep the lines exported and wait until timeout, user input or signal * gpiofind - find the gpiochip name and line offset given the line name * gpiomon - wait for events on GPIO lines, specify which events to watch, how many events to process before exiting or if the events should be reported to the console ## Detect the group of GPIO lines available ### Roadrunner board sudo gpiodetect gpiochip0 [fc038000.pinctrl] (128 lines) gpiochip1 [fc040000.secumod] (8 lines) ### Acqua board sudo gpiodetect gpiochip0 [fffff200.gpio] (32 lines) gpiochip1 [fffff400.gpio] (32 lines) gpiochip2 [fffff600.gpio] (32 lines) gpiochip3 [fffff800.gpio] (32 lines) gpiochip4 [fffffa00.gpio] (32 lines) ## Read the state of each GPIO line ### Roadrunner board sudo gpioinfo fc038000.pinctrl gpiochip0 - 128 lines: line 0: "PA0" unused input active-high line 1: "PA1" unused input active-high line 2: "PA2" unused input active-high line 3: "PA3" unused input active-high line 4: "PA4" unused input active-high ... line 123: "PD27" unused input active-high line 124: "PD28" unused input active-high line 125: "PD29" unused input active-high line 126: "PD30" unused input active-high line 127: "PD31" unused input active-high sudo gpioinfo fc040000.secumod gpiochip1 - 8 lines: line 0: unnamed unused output active-high line 1: unnamed unused input active-high line 2: unnamed unused input active-high line 3: unnamed unused input active-high line 4: unnamed unused input active-high line 5: unnamed unused input active-high line 6: unnamed unused input active-high line 7: unnamed unused input active-high ### Acqua board sudo gpioinfo fffff200.gpio gpiochip0 - 32 lines: line 0: "pioA0" unused input active-high line 1: "pioA1" unused input active-high line 2: "pioA2" unused input active-high line 3: "pioA3" unused input active-high line 4: "pioA4" unused input active-high line 5: "pioA5" unused input active-high line 6: "pioA6" unused input active-high line 7: "pioA7" unused input active-high line 8: "pioA8" unused input active-high line 9: "pioA9" unused input active-high line 10: "pioA10" unused input active-high line 11: "pioA11" unused input active-high line 12: "pioA12" unused input active-high line 13: "pioA13" unused input active-high line 14: "pioA14" unused input active-high line 15: "pioA15" unused input active-high line 16: "pioA16" unused input active-high line 17: "pioA17" unused input active-high line 18: "pioA18" unused input active-high line 19: "pioA19" unused input active-high line 20: "pioA20" unused input active-high line 21: "pioA21" unused input active-high line 22: "pioA22" unused input active-high line 23: "pioA23" unused input active-high line 24: "pioA24" unused input active-high line 25: "pioA25" unused input active-high line 26: "pioA26" unused input active-high line 27: "pioA27" unused input active-high line 28: "pioA28" unused input active-high line 29: "pioA29" unused input active-high line 30: "pioA30" unused input active-high line 31: "pioA31" unused input active-high ## Read the value of a single GPIO line. ### Roadrunner board sudo gpiofind "PA24" gpiochip0 24 sudo gpioget gpiochip0 24 1 wire PA24 to GND and try again: sudo gpioget gpiochip0 24 0 ### Acqua board sudo gpiofind "pioA0" gpiochip0 0 sudo gpioget gpiochip0 0 1 wire PA24 to GND and try again: sudo gpioget gpiochip0 0 0 ## Read two values at the same time. Set the active state of the lines to low. sudo gpioget --active-low gpiochip0 24 25 1 1 ## Set the value of a single line, then exit immediately. This is useful for floating pins. sudo gpioset gpiochip0 24=1 ## Toggle a GPIO by name, then wait for the user to press ENTER. sudo gpioset --mode=wait `gpiofind "PA24"`=1 ## Toggle PA24 high for 1 second. sudo gpioset --mode=time --sec=1 gpiochip0 34=0 ## Wait for three rising edge events on a single GPIO line, then exit. sudo gpiomon --num-events=3 --rising-edge gpiochip0 24 event: RISING EDGE offset: 3 timestamp: [ 1151.814356387] event: RISING EDGE offset: 3 timestamp: [ 1151.815449803] event: RISING EDGE offset: 3 timestamp: [ 1152.091556803] ## Wait for a single falling edge event. Specify a custom output format. sudo gpiomon --format="%e %o %s %n" --falling-edge gpiochip0 24 0 25 1156 615459801 ## Pause execution until a single event of any type occurs. Don't print anything. Find the line by name. sudo gpiomon --num-events=1 --silent `gpiofind "PA24"` ## Monitor multiple lines, exit after the first event. sudo gpiomon --silent --num-events=1 gpiochip0 24 25 31 ## Check the GPIO status sudo cat /sys/kernel/debug/pinctrl/ahb:apb:pinctrl@fffff200/pinmux-pins ## Links * @article='libgpiod' * [libgpiod documentation](https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/README) @include='adv_main'