title: Interrupt handling and user space notification
body: <p>I have several registered interrupts assigned to gpios, and application in user space.
  How to notify application about occurred interrupt and which interrupt there was?</p>
  
  <p>Possibly fasync is applicable for this goal, but I can find examples how to send information from interrupt handler to user space application.</p>
  
  <p>It will be good if you can present some useful examples.</p>
  
  <p>Thanks in advance.</p>