linux 输入子系统(4) intput_dev 接口描述

  • Name
  • struct input_dev — represents an input device
  • Synopsis
  • struct input_dev {
  • const char * name; //name of the device
  • const char * phys; //physical path to the device in the system hierarchy
  • const char * uniq; //unique identification code for the device (if device has it)
  •   struct input_id id; //id of the device (struct input_id)
  •   unsigned long evbit[BITS_TO_LONGS(EV_CNT)]; //bitmap of types of events supported by the device (EV_KEY, EV_REL, etc.)
  •   unsigned long keybit[BITS_TO_LONGS(KEY_CNT)]; //bitmap of keys/buttons this device has
  •   unsigned long relbit[BITS_TO_LONGS(REL_CNT)]; //bitmap of relative axes for the device
  •   unsigned long absbit[BITS_TO_LONGS(ABS_CNT)]; //bitmap of absolute axes for the device
  •   unsigned long mscbit[BITS_TO_LONGS(MSC_CNT)]; //bitmap of miscellaneous events supported by the device
  •   unsigned long ledbit[BITS_TO_LONGS(LED_CNT)]; //bitmap of leds present on the device
  •   unsigned long sndbit[BITS_TO_LONGS(SND_CNT)]; //bitmap of sound effects supported by the device
  •   unsigned long ffbit[BITS_TO_LONGS(FF_CNT)]; //bitmap of force feedback effects supported by the device
  •   unsigned long swbit[BITS_TO_LONGS(SW_CNT)]; //bitmap of switches present on the device
  •   unsigned int keycodemax; //size of keycode table
  •   unsigned int keycodesize; //size of elements in keycode table
  •   void * keycode; //map of scancodes to keycodes for this device
  • /*optional method to alter current keymap, used to implement sparse keymaps.
  • If not supplied default mechanism will be used*/
  • int (* setkeycode) (struct input_dev *dev, int scancode, int keycode);
  • /*optional method to retrieve current keymap. If not supplied default mechanism will be used*/
  • int (* getkeycode) (struct input_dev *dev, int scancode, int *keycode);
  •   struct ff_device * ff; //force feedback structure associated with the device if device supports force feedback effects
  •   unsigned int repeat_key; //stores key code of the last key pressed; used to implement software autorepeat
  •   struct timer_list timer; //timer for software autorepeat
  • int sync; //set to 1 when there were no new events since last EV_SYNC
  • int abs[ABS_MAX + 1]; //current values for reports from absolute axes
  • int rep[REP_MAX + 1]; //current values for autorepeat parameters (delay, rate)
  •   unsigned long key[BITS_TO_LONGS(KEY_CNT)]; //reflects current state of device‘s keys/buttons
  •   unsigned long led[BITS_TO_LONGS(LED_CNT)]; //reflects current state of device‘s LEDs
  •   unsigned long snd[BITS_TO_LONGS(SND_CNT)]; //reflects current state of sound effects
  •   unsigned long sw[BITS_TO_LONGS(SW_CNT)]; //reflects current state of device‘s switches
  • int absmax[ABS_MAX + 1]; //maximum values for events coming from absolute axes
  • int absmin[ABS_MAX + 1]; //minimum values for events coming from absolute axes
  • int absfuzz[ABS_MAX + 1]; //describes noisiness for axes
  • int absflat[ABS_MAX + 1]; //size of the center flat position (used by joydev)
  • /*this method is called when the very first user calls input_open_device.
  • The driver must prepare the device to start generating events (start polling
  • thread, request an IRQ, submit URB, etc.) */
  • int (* open) (struct input_dev *dev);
  •   void (* close) (struct input_dev *dev); //this method is called when the very last user calls input_close_device.
  • /*purges the device. Most commonly used to get rid of force feedback effects
  •   loaded into the device when disconnecting from it */
  • int (* flush) (struct input_dev *dev, struct file *file);
  • /*event handler for events sent _to_ the device, like EV_LED or EV_SND.
  •   The device is expected to carry out the requested action (turn on a LED, play sound, etc.)
  •   The call is protected by event_lock and must not sleep */
  • int (* event) (struct input_dev *dev, unsigned int type, unsigned int code, int value);
  • /*input handle that currently has the device grabbed (via EVIOCGRAB ioctl).
  •   When a handle grabs a device it becomes sole recipient for all input events coming from the device */
  •   struct input_handle * grab;
  • /*this spinlock is is taken when input core receives and processes a new event for the device (in input_event). Code that accesses and/or modifies parameters of a device (such as keymap or absmin, absmax, absfuzz, etc.) after device has been registered with input core must take this lock. */
  •   spinlock_t event_lock;
  •   struct mutex mutex; //serializes calls to open, close and flush methods
  • /*stores number of users (input handlers) that opened this device. It is used by input_open_device and input_close_device to make sure that dev->open is only called when the first user opens device and dev->closeis called when the very last user closes the device */
  •   unsigned int users;
  • int going_away; //marks devices that are in a middle of unregistering and causes input_open_device*() fail with -ENODEV.
  •   struct device dev; //driver model‘s view of this device
  •   struct list_head h_list; //list of input handles associated with the device. When accessing the list dev->mutex must be held
  •   struct list_head node; //used to place the device onto input_dev_list
  • };
    • 时间： 2024-08-02 06:09:13

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