Issue while trying to read or set the status of this pin A core - IMX8ULPEVK9

[dhruvinrajpura]

I am currently working with the i.MX8ULP EVK9 and attempting to read the status of a button present on the EVK. The button is connected to the GPIO pin PTE17_PTE17 (Switch 2). However, I am facing issues when trying to read or set the status of this pin using the gpioset and gpioget commands.

Here are the details of the commands and the errors encountered:

Command : gpioset /dev/gpiochip4 17=0

Error : gpioset: invalid line value: '/dev/gpiochip4' Command : gpioget 4 17

Error : gpioget: invalid line value: '4' gpioget: invalid line value: '17' Are there any other changes we are supposed to do in the DTSI file further?

[Chavira]

HI @dhruvinrajpura!

Thank you for contacting NXP Support!

You are using wrong the commands.

To set a gpio you should use:

gpioset -c gpiochip4 17=0
gpioset -c gpiochip4 17=1

To get a value you should use:

gpioget -c gpiochip4 17

Best Regards!

Chavira

[dhruvinrajpura]

Hello @Chavira 

We tried the command "gpioget -c gpiochip4 17" and got the following log:

root@imx8ulpevk:~# gpioget -c gpiochip4 17

"17"=active

When we press the button, it also shows the active state. I checked on the EVK, and when the button is pressed, the voltage goes from 1.8V to 0V.

When I enter the gpioinfo command, I get this output:

gpiochip4 - 32 lines:

line 0: unnamed input

line 1: unnamed input

line 2: unnamed input

line 3: unnamed input

line 4: unnamed input

line 5: unnamed input

line 6: unnamed input

line 7: unnamed input

line 8: unnamed input

line 9: unnamed input

line 10: unnamed input

line 11: unnamed input active-low consumer=PowerOn

line 12: unnamed input

line 13: unnamed input

line 14: unnamed input

line 15: unnamed input

line 16: unnamed input

line 17: unnamed input

line 18: unnamed input

line 19: unnamed input

line 20: unnamed input

line 21: unnamed input

line 22: unnamed input

line 23: unnamed input

line 24: unnamed input

line 25: unnamed input

line 26: unnamed input

line 27: unnamed input

line 28: unnamed input

line 29: unnamed input

line 30: unnamed input

line 31: unnamed input

From the log, I can see that pin 17 on gpiochip4 is set as an input. What should I check to get the correct state of the pin? I'm using a pre-built Yocto image. Please let me know if I need to make any changes to the Yocto image.

Thanks

[Chavira]

Hi @dhruvinrajpura!

You have to modify the device tree according to your needs.

You can refer to the next community post:

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/How-to-use-Devshell-to-compile-device-tr...

Best Regards!

Chavira