My intention was to use it for reading an i-button via 1-wire Dallas. I had no time, however, to go deeply into this. I've finally used another method to read the i-button : there are a number of files that contain information about the i-button (present or not, the key-code,...). By reading these files, I could detect the presence of a key and read out its code. However, I feel like this is not the right method to handle this. I have to investigate this further into detail later on.
Thanks for your reply !