RadxaYuntian: /* Set GPIO pin level */

2022-10-31T10:21:24Z

‎Set GPIO pin level

RadxaYuntian at 10:37, 7 January 2022

2022-01-07T10:37:09Z

RadxaYuntian at 09:36, 6 January 2022

2022-01-06T09:36:20Z

RadxaYuntian: Created page with "{{Languages|gpiod}} = Use gpiod to control GPIO pins = Traditionally GPIO pins are exposed by Linux kernel under `/sys/class/gpio` namespace. However, this interf..."

2022-01-06T09:06:37Z

Created page with "{{Languages|gpiod}} = Use gpiod to control GPIO pins = Traditionally GPIO pins are exposed by Linux kernel under <code>/sys/class/gpio</code> namespace. However, this interf..."

New page

{{Languages|gpiod}}

= Use gpiod to control GPIO pins =

Traditionally GPIO pins are exposed by Linux kernel under <code>/sys/class/gpio</code> namespace. However, this interface has been [https://www.kernel.org/doc/Documentation/gpio/sysfs.txt deprecated] since version 4.8. The replacement is a C binding called <code>libgpiod</code>, along with a set of user land tools called <code>gpiod</code>.

In this guide we will talk about some common usage of <code>gpiod</code> so you can start incorporate them in your projects.

== Installation ==

Run following command under Debian/Ubuntu:

sudo apt update
sudo apt install gpiod -y

== List available GPIO controller ==

radxa@radxa-zero2:~$ sudo gpioinfo
gpiochip0 - 85 lines:
line 0: "PIN_27" unused input active-high
line 1: "PIN_28" unused input active-high
line 2: "PIN_7" unused input active-high
line 3: "PIN_11" unused input active-high
line 4: "PIN_13" unused input active-high
line 5: "PIN_14" unused input active-high
line 6: "PIN_18" unused input active-high
line 7: "PIN_40" unused input active-high
line 8: unnamed unused input active-high
line 9: unnamed unused input active-high
line 10: unnamed unused input active-high
line 11: unnamed unused input active-high
line 12: unnamed unused input active-high
line 13: unnamed unused input active-high
line 14: unnamed unused input active-high
line 15: unnamed unused input active-high
line 16: unnamed unused input active-high
line 17: unnamed unused input active-high
line 18: unnamed unused input active-high
line 19: unnamed unused input active-high
line 20: "PIN_19" unused input active-high
line 21: "PIN_21" unused input active-high
line 22: "PIN_24" unused input active-high
line 23: "PIN_23" unused input active-high
line 24: unnamed unused input active-high
line 25: unnamed unused input active-high
line 26: unnamed unused input active-high
line 27: unnamed unused input active-high
line 28: unnamed unused input active-high
line 29: unnamed unused input active-high
line 30: unnamed unused input active-high
line 31: unnamed unused input active-high
line 32: unnamed unused input active-high
line 33: unnamed unused input active-high
line 34: unnamed unused input active-high
line 35: unnamed unused input active-high
line 36: unnamed unused input active-high
line 37: unnamed "reset" output active-low [used]
line 38: unnamed unused input active-high
line 39: unnamed unused input active-high
line 40: unnamed unused input active-high
line 41: unnamed unused input active-high
line 42: unnamed unused input active-high
line 43: unnamed unused input active-high
line 44: unnamed unused input active-high
line 45: unnamed unused input active-high
line 46: unnamed unused input active-high
line 47: unnamed "cd" input active-low [used]
line 48: "PIN_36" unused input active-high
line 49: "PIN_32" unused input active-high
line 50: "PIN_12" unused input active-high
line 51: "PIN_35" unused input active-high
line 52: unnamed unused input active-high
line 53: unnamed unused input active-high
line 54: "PIN_38" unused input active-high
line 55: unnamed unused input active-high
line 56: unnamed unused input active-high
line 57: unnamed unused input active-high
line 58: unnamed unused input active-high
line 59: unnamed unused input active-high
line 60: unnamed unused input active-high
line 61: unnamed "green:status" output active-high [used]
line 62: "PIN_31" unused input active-high
line 63: "PIN_3" unused input active-high
line 64: "PIN_25" unused input active-high
line 65: unnamed unused input active-high
line 66: unnamed unused input active-high
line 67: unnamed unused input active-high
line 68: unnamed unused input active-high
line 69: unnamed unused input active-high
line 70: unnamed unused input active-high
line 71: unnamed "reset" output active-low [used]
line 72: unnamed unused input active-high
line 73: unnamed unused input active-high
line 74: unnamed unused input active-high
line 75: unnamed unused input active-high
line 76: unnamed unused input active-high
line 77: unnamed unused input active-high
line 78: unnamed unused input active-high
line 79: unnamed unused input active-high
line 80: unnamed unused input active-high
line 81: unnamed unused input active-high
line 82: unnamed "shutdown" output active-high [used]
line 83: unnamed unused input active-high
line 84: unnamed unused input active-high
gpiochip1 - 15 lines:
line 0: "PIN_8" unused input active-high
line 1: "PIN_10" unused input active-high
line 2: unnamed unused input active-high
line 3: unnamed "power" input active-low [used]
line 4: unnamed unused output active-high
line 5: unnamed unused input active-high
line 6: unnamed unused input active-high
line 7: "PIN_29" unused input active-high
line 8: "PIN_33" unused input active-high
line 9: "PIN_37" unused input active-high
line 10: unnamed unused input active-high
line 11: unnamed unused output active-high
line 12: unnamed unused input active-high
line 13: unnamed unused input active-high
line 14: unnamed unused input active-high

== Convert 40-pin header number to gpiod device number ==

radxa@radxa-zero2:~$ sudo gpiofind PIN_8
gpiochip1 0

== Read GPIO pin level ==

radxa@radxa-zero2:~$ sudo gpioget $(sudo gpiofind PIN_8)
1

== Set GPIO pin level ==

radxa@radxa-zero2:~$ sudo gpioset $(sudo gpiofind PIN_8)=0
radxa@radxa-zero2:~$ sudo gpioset $(sudo gpiofind PIN_8)=1

@@ Line 132: / Line 132: @@
 == Set GPIO pin level ==
-     radxa@radxa-zero2:~$ sudo gpioset $(sudo gpiofind PIN_8)=0
+     radxa@radxa-zero2:~$ sudo gpioset -m signal $(sudo gpiofind PIN_8)=0
-     radxa@radxa-zero2:~$ sudo gpioset $(sudo gpiofind PIN_8)=1
+     radxa@radxa-zero2:~$ sudo gpioset -m signal $(sudo gpiofind PIN_8)=1
 == Watch GPIO level change ==

← Older revision		Revision as of 10:37, 7 January 2022
Line 141:		Line 141:
	radxa@radxa-zero2:~$ sudo gpiomon -f $(sudo gpiofind PIN_37)		radxa@radxa-zero2:~$ sudo gpiomon -f $(sudo gpiofind PIN_37)
	event: FALLING EDGE offset: 0 timestamp: [ 3882.313792858]		event: FALLING EDGE offset: 0 timestamp: [ 3882.313792858]
		+
		+	== A simple GPIO test script based on gpiod ==
		+
		+	[https://gist.github.com/RadxaYuntian/5ef87b9655239e65c9ccb7897c5f618a Here] is a sample script that uses <code>gpiod</code> to test all onboard GPIO pins.

← Older revision		Revision as of 09:36, 6 January 2022
Line 134:		Line 134:
	radxa@radxa-zero2:~$ sudo gpioset $(sudo gpiofind PIN_8)=0		radxa@radxa-zero2:~$ sudo gpioset $(sudo gpiofind PIN_8)=0
	radxa@radxa-zero2:~$ sudo gpioset $(sudo gpiofind PIN_8)=1		radxa@radxa-zero2:~$ sudo gpioset $(sudo gpiofind PIN_8)=1
		+
		+	== Watch GPIO level change ==
		+
		+	You need to specify either <code>-r</code> for rising edge events or <code>-f</code> for falling edge events, but not both.
		+
		+	radxa@radxa-zero2:~$ sudo gpiomon -f $(sudo gpiofind PIN_37)
		+	event: FALLING EDGE offset: 0 timestamp: [ 3882.313792858]

Gpiod - Revision history

RadxaYuntian: /* Set GPIO pin level */

RadxaYuntian at 10:37, 7 January 2022

RadxaYuntian at 09:36, 6 January 2022

RadxaYuntian: Created page with "{{Languages|gpiod}} = Use gpiod to control GPIO pins = Traditionally GPIO pins are exposed by Linux kernel under /sys/class/gpio namespace. However, this interf..."

RadxaYuntian: Created page with "{{Languages|gpiod}} = Use gpiod to control GPIO pins = Traditionally GPIO pins are exposed by Linux kernel under `/sys/class/gpio` namespace. However, this interf..."