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Issue Date Notes
2024/02/02 DESK-MX9-L-5.0.0 release

Peripheral GPIOs[edit | edit source]

i.MX93 can handle external pins in many different ways and most of them can be configured as GPIOs. When a pin is set as a GPIO, it is possible to read its value, change its direction or change output value directly from the shell.

Device tree configuration[edit | edit source]

Here below is an example of device tree configuration for using the GPIOs and enabling UART2 on standard DAVE's kit for the AURA SOM:

From imx93-aura-cb2001.dts:

	leds {
		compatible = "gpio-leds";
		status = "okay";

		uart2_en {
			label = "uart2_en";
			pinctrl-names = "default";
			pinctrl-0 = <&pinctrl_uart2_en>;
			gpios = <&gpio2 4 GPIO_ACTIVE_HIGH>;
			default-state = "on";

		uart2_mode {
			label = "uart2_mode";
			pinctrl-names = "default";
			pinctrl-0 = <&pinctrl_uart2_mode>;
			gpios = <&gpio3 27 GPIO_ACTIVE_HIGH>;
			default-state = "off";
			status = "disabled";

while the related pad configuration has been defined in the iomuxc section:

	pinctrl_uart2_mode: uart2_mode {
		fsl,pins = <
			MX93_PAD_CCM_CLKO2__GPIO3_IO27			0x31e

Accessing the peripheral[edit | edit source]

Linux messages at boot time[edit | edit source]

With the previous leds configuration for the GPIOs, it is possible to find them on sysfs under /sys/class/leds sub-directory:

root@desk-mx93:~# ls -la /sys/class/leds/uart2*
total 0
lrwxrwxrwx  1 root root 0 Mar  3  2023 uart2_en -> ../../devices/platform/leds/leds/uart2_en

Usage with libgpiod[edit | edit source]

Information about GPIOs library libgpiod - C library and tools - can be found on

It is possible to compile libgpiod in the target (if the related Yocto package is not available for installation). Once the autoconf-archive package has been installed

dnf install autoconf-archive

it is possible to clone the libgpiod git repository and compile the related sources:

git clone
cd libgpiod 
./ --enable-tools=yes --prefix=/usr/local 
make install

Once installed, the gpio utilities are available in the target:

root@desk-mx93:~# gpio
gpiodetect  gpioget     gpioinfo    gpiomon     gpionotify  gpioset
gpiomon example[edit | edit source]

If a push button, with proper pull-up, is connected to a GPIO line available - for example using the J33.28 pin available on SBC AXEL Lite WIDE connector - the related GPIO can be used as an interrupt:

  • J33.28 is connected to J10.191 SO-DIMM pin
    • J33 connector is the WIDE connector in the AURA Evaluation Kit
    • J10 connector is the SO-DIMM connector in the AURA Evaluation Kit
    • ALT-0 alternate function for this pin is GPIO2_IO12
  • the corresponding pin number is associated to gpiochip0 line 12
  • gpiomon utility can be used for monitor the pin status and triggering, for example, the falling-edge event:
root@desk-mx93:~# gpiomon -e falling -c 0 12
503.836012614   falling gpiochip0 12
504.229875114   falling gpiochip0 12
504.229962281   falling gpiochip0 12
504.229970823   falling gpiochip0 12
gpioset example[edit | edit source]

For changing a GPIO output status, the gpioset utility can be used:

  • the following example set to High the pin GPIO_IO00 connected to J10.179 SO-DIMM pin
root@desk-mx93:~# gpioset -c 0 0=1