title: unable to export a gpio pin
body: <p>I am trying to export a pin (no. 110) using the following in linux:<br>
  <code>echo 110 &gt; /sys/class/gpio/export</code>  </p>
  
  <p>When I try to do so, I getthe error message<br>
  <code>ash: write error: Device or resource busy</code>  </p>
  
  <p>As per my knowledge the pin is not being used by any module, but I may be wrong. I had the hardware line probed and the voltage is changing, the processor seems to be driving something to the line.<br>
  The pin according to the user manual is not multiplexed and is "commonly available".  </p>