struct input

struct input_handler
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Name

struct input_handler — implements one of interfaces for input devices

Synopsis

struct input_handler {
  void * private;
  void (* event) (struct input_handle *handle, unsigned int type, unsigned int code, int value);
  void (* events) (struct input_handle *handle,const struct input_value *vals, unsigned int count);
  bool (* filter) (struct input_handle *handle, unsigned int type, unsigned int code, int value);
  bool (* match) (struct input_handler *handler, struct input_dev *dev);
  int (* connect) (struct input_handler *handler, struct input_dev *dev, const struct input_device_id *id);
  void (* disconnect) (struct input_handle *handle);
  void (* start) (struct input_handle *handle);
  bool legacy_minors;
  int minor;
  const char * name;
  const struct input_device_id * id_table;
  struct list_head h_list;
  struct list_head node;
};

Members

private: driver-specific data
event: event handler. This method is being called by input core with interrupts disabled and dev->event_lock spinlock held and so it may not sleep
events: event sequence handler. This method is being called by input core with interrupts disabled and dev->event_lock spinlock held and so it may not sleep
filter: similar to event; separates normal event handlers from “filters”.
match: called after comparing device's id with handler's id_table to perform fine-grained matching between device and handler
connect: called when attaching a handler to an input device
disconnect: disconnects a handler from input device
start: starts handler for given handle. This function is called by input core right after connect method and also when a process that “grabbed” a device releases it
legacy_minors: set to true by drivers using legacy minor ranges
minor: beginning of range of 32 legacy minors for devices this driver can provide
name: name of the handler, to be shown in /proc/bus/input/handlers
id_table: pointer to a table of input_device_ids this driver can handle
h_list: list of input handles associated with the handler
node: for placing the driver onto input_handler_list

Description

Input handlers attach to input devices and create input handles. There are likely several handlers attached to any given input device at the same time. All of them will get their copy of input event generated by the device.

The very same structure is used to implement input filters. Input core allows filters to run first and will not pass event to regular handlers if any of the filters indicate that the event should be filtered (by returning true from their filter method).

Note that input core serializes calls to connect and disconnect methods.