GPIOs number of the IMX93

[Embedded-world]

Dear Experts,

I'm working on the IMX93 board bring-up. During testing of the RS485 peripherals, we used one of the GPIO pins (i.e., GPIO2_IO00) to toggle between logic 0 and logic 1.

While researching resources about GPIO configuration for the IMX93, I came across the method to find GPIO numbers using:

cat /sys/kernel/debug/gpio

Our board is based on the IMX9352 processor. For GPIO2_IO00, I used the GPIO number 512,

and it worked correctly for the board. but, I would like to understand how this GPIO is configured. How is the GPIO number calculated for the IMX93 processor? Is there a specific formula for determining this? If so, could you please provide it?

Thanks & Regards

Ravikumar

[Embedded-world]

Hi @Manuel_Salas 

Thanks for sharing the this information, It's very useful.

Best Regards,

Ravikumar

[Manuel_Salas · Accepted solution]

Hello @Embedded-world 

I hope you are doing very well.

Linux kernel base the GPIO number based on the index, in this case:

• gpiochip0: GPIOs 512-543, parent: platform/43810000 (real GPIO is GPIO2)
• gpiochip1: GPIOs 544-575, parent: platform/43820000 (real GPIO is GPIO3)
• gpiochip2: GPIOs 576-607, parent: platform/43830000 (real GPIO is GPIO4)
• gpiochip3: GPIOs 608-639, parent: platform/47400000 (real GPIO is GPIO1)

But as I said, Linux kernel take as reference the index, so Real index:

• Real GPIO2 is Index 0
• Real GPIO3 is Index 1
• Real GPIO4 is Index 2
• Real GPIO1 is Index 3

You can use this formula to calculate your desired pin:

GPIO_NUMBER = GPIO_BASE_INDEX + PIN_INDEX

As example, we can take the GPIO2_IO00:

GPIO_NUMBER = (512) + (0) = 512.

Also, you can take a look to the gpiod tool installed by default in our BSP. It is easy to use (gpiodetect, gpioset, gpioget, etc.):

I hope this can helps to you.

Best regards,

Salas.