Controlling the System Controller GPIO from Linux IMX8QM

[st3v3n]

I have a custom board using the IMX8QM and I need to be able to control the SCU GPIO from linux.

I have enabled the scu gpio from the kernel found the imx_scu gpio driver.

Added the libgpiod and when doing gpioinfo I was able to see scu gpio showing with 8 lines, but when I try to read a value from it using 'gpioget gpiochip8 4'   I get the following:

imxscfw_get: failed -22

gpioget: error reading GPIO values: Invalid argument

Added this to the device tree:

scu_gpio0: scu-gpio0 {
compatible = "fsl,imx-scu-gpio";
gpio-controller;
#gpio-cells = <2>;
#interrupt-cells = <2>;
};

Using buildroot to build the linux(5.15.5) and bootloader.

SCFW Version:

imx-scfw-porting-kit-1.14.0

[joanxie]

pls add more debug information in the function as below to check which one is wrong, it seems this gpio you add doesn't controlled by the scu correctly,

if (offset >= sizeof(sc_arr)/sizeof(unsigned int))
return err;

err = imx_sc_misc_get_control(scu->handle, sc_arr[offset],
0, &level)

https://github.com/nxp-imx/linux-imx/blob/lf-5.15.y/drivers/gpio/gpio-scu.c#L37