i.MX ProcessorsのトピックRe: Accessing GPIO from User space for LED Board Control.

Accessing GPIO from User space for LED Board Control.

MJD — Sat, 11 May 2024 10:31:33 GMT

Hello,

I am using UART3_RXD_3V3 (GPIO5_IO08), UART3_TXD_3V3 (GPIO5_IO07) gpios connected with LED Board.

When i try to check the GPIO Set value i am not to able set this with sysfs
Bellow are the gpio
root@imx8mp-lpddr4-evk:~# find / -name "gpio"
find: '/proc/2514': No such file or directory
/lib/modules/6.1.55+g770c5fe2c1d1/kernel/drivers/gpio
/sys/kernel/debug/gpio
/sys/bus/gpio
/sys/firmware/devicetree/base/regulator-pcie/gpio
/sys/firmware/devicetree/base/regulator-vbus/gpio
/sys/firmware/devicetree/base/regulator-audio-pwr/gpio
/sys/firmware/devicetree/base/regulator-can2-stby/gpio
/sys/firmware/devicetree/base/regulator-can1-stby/gpio
/sys/firmware/devicetree/base/regulator-usdhc2/gpio
root@imx8mp-lpddr4-evk:~#

Is there any specific config need to enable to operate from sysyfs, apart from the bellow
CONFIG_SYSFS=y
CONFIG_PWM_SYSFS=y

root@imx8mp-lpddr4-evk:~# ls /sys/class/g
gpu_class/ graphics/
root@imx8mp-lpddr4-evk:~# ls /sys/class/g

As with the blow attached document i tried to check.

Is there anything need to be enabled?
Guide me to SET and read the value form the GPIO5_IO08 GPIO5_IO07.
Is there any Dts configuration has reference will be helpful.

ThankYou

Re: Accessing GPIO from User space for LED Board Control.

JorgeCas — Mon, 13 May 2024 20:35:49 GMT

Hello,

You need to add the GPIO on device tree and change the IOMUX configuration.

You can take as a reference the EVK device tree.

Best regards.

Re: Accessing GPIO from User space for LED Board Control.

MJD — Sat, 18 May 2024 09:31:01 GMT

Hi @JorgeCas

I have configured Dts to use GPIO5_IO07 pin from user space has bellow.

#define MX8MP_IOMUXC_ECSPI1_MOSI__GPIO5_IO07 0x1E4 0x444 0x000 0x5 0x0

root@imx8mp-lpddr4-evk:~# echo 135 > /sys/class/gpio/export
root@imx8mp-lpddr4-evk:~# echo out > /sys/class/gpio/gpio135/direction
root@imx8mp-lpddr4-evk:~# cat /sys/class/gpio/gpio135/value
0
root@imx8mp-lpddr4-evk:~# echo 1 > /sys/class/gpio/gpio135/value
root@imx8mp-lpddr4-evk:~# cat /sys/class/gpio/gpio135/value
1
root@imx8mp-lpddr4-evk:~#

I am able set the value but when i probe with that pin, i do not see any changes on the pin, will always be High.

Is there any changes need to be done in my dts?

Any one give any me pin configuration with Dts to use GPIO in Userspace.

With the bellow link i am not able to set.
root@imx8mp-lpddr4-evk:~#
root@imx8mp-lpddr4-evk:~# gpioset -c gpiochip4 7=1

The above command doesn't execute

https://variwiki.com/index.php?title=MX8M_GPIO