I have developed a character device driver for Linux. I have some functions that deal with files (in the file operations struct) such as read,write,ioctl,etc..
I realised (via the use of printks) that, after initialising the driver and creating the node, when I call the write function for the first time (which will call the open function for the first time too) the system is calling the ioctl function, with parameters:
cmd = 21505
arg = 2125423388
What do these numbers mean and why is the IOCTL being called in this case?