title: Using GPIO pins on Intel Atom D525
body: <p>I have a D525 Intel Atom (<a href="http://www.amazon.ca/Jetway-NF38QLB-525-Generation-Intel-1-80GHz13W/dp/B00ABZRTDU" rel="nofollow">http://www.amazon.ca/Jetway-NF38QLB-525-Generation-Intel-1-80GHz13W/dp/B00ABZRTDU</a>) which appears to have GPIO pins.</p>
  
  <p>I am using the 4.2 Linux kernel and can see the directory /sys/class/gpio/ (this appeared after updating to 4.2) however I cannot seem to interact with the GPIOs. I have followed instructions here: <a href="https://www.ridgerun.com/developer/wiki/index.php/How_to_use_GPIO_signals" rel="nofollow">https://www.ridgerun.com/developer/wiki/index.php/How_to_use_GPIO_signals</a> however I just get the following error when trying to export the gpio</p>
  
  <pre><code>root@wheezy7.8:/# cd /sys/class/gpio/
  root@wheezy7.8:/sys/class/gpio# GPIO=1
  root@wheezy7.8:/sys/class/gpio# echo $GPIO &gt; export
  bash: echo: write error: Invalid argument
  </code></pre>
  
  <p>I have tried numerous pin numbers (1-32), but no luck...</p>
  
  <p>Here is the output from modinfo gpio_ich</p>
  
  <pre><code>root@wheezy7.8:/sys/class/gpio# modinfo gpio_ich
  filename:       /lib/modules/4.2.0-040200-generic/kernel/drivers/gpio/gpio-  ich.ko
  alias:          platform:gpio_ich
  license:        GPL
  description:    GPIO interface for Intel ICH series
  author:         Peter Tyser &lt;ptyser@xes-inc.com&gt;
  srcversion:     338BC4F9B47008C478E28F3
  depends:        
  intree:         Y
  vermagic:       4.2.0-040200-generic SMP mod_unload modversions 686 
  parm:           gpiobase:The GPIO number base. -1 means dynamic, which is the     default. (int)
  </code></pre>
  
  <p>I have also dumped the configuration (following instructions from the first link):</p>
  
  <pre><code>root@wheezy7.8:~$ mount -t debugfs none /sys/kernel/debug
  root@wheezy7.8:~$ cat /sys/kernel/debug/gpio
  GPIOs 462-511, platform/gpio_ich.1.auto, gpio_ich:
  </code></pre>
  
  <p>This seems to suggest that the pins are 462 to 511, which is not the case:</p>
  
  <pre><code>root@wheezy7.8:/sys/class/gpio# GPIO=462
  root@wheezy7.8:/sys/class/gpio# echo $GPIO &gt; export
  bash: echo: write error: No such device
  root@wheezy7.8:/sys/class/gpio# GPIO=511
  root@wheezy7.8:/sys/class/gpio# echo $GPIO &gt; export
  bash: echo: write error: No such device
  </code></pre>