Inputting device structures

First of all, the main file to include, in order to interface with the input subsystem is linux/input.h:

#include <linux/input.h> 

No matter what type of input device it is, and what type of event it sends, an input device is represented in the kernel as an instance of struct input_dev:

struct input_dev { 
  const char *name; 
  const char *phys; 
 
  unsigned long evbit[BITS_TO_LONGS(EV_CNT)]; 
  unsigned long keybit[BITS_TO_LONGS(KEY_CNT)]; 
  unsigned long relbit[BITS_TO_LONGS(REL_CNT)]; 
  unsigned long absbit[BITS_TO_LONGS(ABS_CNT)]; 
  unsigned long mscbit[BITS_TO_LONGS(MSC_CNT)]; 
 
  unsigned int repeat_key; 
 
  int rep[REP_CNT]; 
  struct input_absinfo *absinfo; 
  unsigned long key[BITS_TO_LONGS(KEY_CNT)]; 
 
  int (*open)(struct input_dev *dev); 
  void (*close)(struct input_dev *dev); 
 
  unsigned int users; 
  struct device dev; 
 
  unsigned int num_vals; 
  unsigned int max_vals; 
  struct input_value *vals; 
 
  bool devres_managed; 
}; 

The...