Controlling the System Controller GPIO from Linux IMX8QM

st3v3n — Tue, 18 Feb 2025 21:21:27 GMT

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

Re: Controlling the System Controller GPIO from Linux IMX8QM

joanxie — Sat, 22 Feb 2025 07:36:58 GMT

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

i.MX ProcessorsのトピックControlling the System Controller GPIO from Linux IMX8QM

Controlling the System Controller GPIO from Linux IMX8QM

Re: Controlling the System Controller GPIO from Linux IMX8QM