STM32mp1 pin mux in kernel dts

[Ara.1]

currently i have a pin <STM32_PINMUX('F', 14, GPIO)> how to mux as a GPIO before using as a gpiolib, export work fine, but i2c4 is not working but i can see GPIO is getting based on sys gpiolib.

as before export i see PF14 line is muxed as pin 94 (PF14): input - low - pull up

and this line has AF as a i2c4-clk

[OlivierK]

Hi Ara.1 (Community Member)

I am not sure to understand what you try to acheive here. if you've declared PF14 as AF assigned to i2c4-clk, the i2c driver will use this pin (pinctrl framework). This is mutually exclusive to control PF14 as a GPIO using gpiolib framework.

Maybe a good starting point: https://wiki.st.com/stm32mpu/wiki/Overview_of_GPIO_pins

Regards,

Olivier

[Ara.1]

1. i2c is not working when i do sysfs gpio activity on PF14,
2. but when i use same PF14 pin set via gpiochip , i2c works neatly

point 1

 echo 94 > /sys/class/gpio/export  -

point 2

gpioset gpiochip5 14=1

[OlivierK]

Hi Ara.1 (Community Member)

Understood...

sysfs gpio is deprecated since Linux 4.8, you should use gpiochip instead.

BR

Olivier

[Ara.1]

sysfs gpio i can set and reset, same reflecting on PF14, but why i2c4 lines are different touch is failing this looks strange.

[PatrickF]

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