title: Linux Userspace GPIO Interrupts using sysfs
body: <p>I would like to use interrupts with GPIO on userspace using sysfs.
  I use these commands :</p>
  
  <pre><code>[root@at91]:gpio109 &gt; echo 109 &gt; export
  [root@at91]:gpio109 &gt; cd gpio109/
  [root@at91]:gpio109 &gt; ll
  -rw-r--r--    1 root     0            4096 Jan  1 00:17 direction
  drwxr-xr-x    2 root     0               0 Jan  1 00:17 power
  lrwxrwxrwx    1 root     0               0 Jan  1 00:17 subsystem -&gt; ../../gpio
  -rw-r--r--    1 root     0            4096 Jan  1 00:17 uevent
  -rw-r--r--    1 root     0            4096 Jan  1 00:17 value
  </code></pre>
  
  <p>The gpio works well but I can't use interrupts.
  I read everywhere i must have an edge file to poll this file. But on my system this file doesn't exist.
  I made a lot of tries to find a solution but remain unsuccessfull.</p>
  
  <p>My target is an AT91SAM9263 on linux kernel 2.6.30.</p>
  
  <p>At the boot of my board I got this message on interrupts :</p>
  
  <pre><code>AT91: 160 gpio irqs in 5 banks
  </code></pre>
  
  <p>which show that the function <code>at91_gpio_irq_setup()</code> is well executed.</p>
  
  <p>Have you any idea ?</p>