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GPIO controllers_Kernel

Former Member

Hi,

Im booting Linux on a Microzed 7010

I tried to see which gpio controlles are available so i did /sys/kernel/debug/gpio but when accessing the kernel i only see:

fscaps   notes                           uevent_helper

mm       rcu_expidited             uevent_segnum
 
any help??

  • 0

    What Linux are you booting?  PetaLinux?

    Take a look in /sys/class/gpio.  You should see your gpio peripheral(s) there, e.g. named gpiochip0, etc.  If you don't see any gpiochip<n> devices listed, but expect to see them, you likely have a mismatch between your hardware platform (Zynq PL bitstream) and Linux devicetree.  You can follow the instructions here to manually exercise the GPIO bits (read switches, toggle LEDs, etc.):

    http://www.wiki.xilinx.com/Linux+GPIO+Driver

    If you are booting PetaLinux you can use the provided gpio-demo application to exercise the GPIO bits using the steps below:

    1.   If you haven’t already, login to PetaLinux using the provided credentials.
    1.   Identify the location of the GPIO peripherals.  Enter the following command to print the kernel boot and diagnostic messages and pipe the output through a grep filter to locate the GPIO peripherals in the system:

    # dmesg |grep gpio

    1.   You many experiment with the gpio-demo application to turn on the LEDs and read the switches.  Enter the following command to turn on an LED:

    # gpio-demo -g <gpio base> -o 0x1

    1.   Use the application to read the DIP and PB switches.

    # gpio-demo -g <gpio base> –i