LXR linux/drivers/staging/speakup/fakekey.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/* fakekey.c
   3 * Functions for simulating keypresses.
   4 *
   5 * Copyright (C) 2010 the Speakup Team
   6 */
   7#include <linux/types.h>
   8#include <linux/slab.h>
   9#include <linux/preempt.h>
  10#include <linux/percpu.h>
  11#include <linux/input.h>
  12
  13#include "speakup.h"
  14
  15#define PRESSED 1
  16#define RELEASED 0
  17
  18static DEFINE_PER_CPU(int, reporting_keystroke);
  19
  20static struct input_dev *virt_keyboard;
  21
  22int speakup_add_virtual_keyboard(void)
  23{
  24        int err;
  25
  26        virt_keyboard = input_allocate_device();
  27
  28        if (!virt_keyboard)
  29                return -ENOMEM;
  30
  31        virt_keyboard->name = "Speakup";
  32        virt_keyboard->id.bustype = BUS_VIRTUAL;
  33        virt_keyboard->phys = "speakup/input0";
  34        virt_keyboard->dev.parent = NULL;
  35
  36        __set_bit(EV_KEY, virt_keyboard->evbit);
  37        __set_bit(KEY_DOWN, virt_keyboard->keybit);
  38
  39        err = input_register_device(virt_keyboard);
  40        if (err) {
  41                input_free_device(virt_keyboard);
  42                virt_keyboard = NULL;
  43        }
  44
  45        return err;
  46}
  47
  48void speakup_remove_virtual_keyboard(void)
  49{
  50        if (virt_keyboard) {
  51                input_unregister_device(virt_keyboard);
  52                virt_keyboard = NULL;
  53        }
  54}
  55
  56/*
  57 * Send a simulated down-arrow to the application.
  58 */
  59void speakup_fake_down_arrow(void)
  60{
  61        unsigned long flags;
  62
  63        /* disable keyboard interrupts */
  64        local_irq_save(flags);
  65        /* don't change CPU */
  66        preempt_disable();
  67
  68        __this_cpu_write(reporting_keystroke, true);
  69        input_report_key(virt_keyboard, KEY_DOWN, PRESSED);
  70        input_report_key(virt_keyboard, KEY_DOWN, RELEASED);
  71        input_sync(virt_keyboard);
  72        __this_cpu_write(reporting_keystroke, false);
  73
  74        /* reenable preemption */
  75        preempt_enable();
  76        /* reenable keyboard interrupts */
  77        local_irq_restore(flags);
  78}
  79
  80/*
  81 * Are we handling a simulated keypress on the current CPU?
  82 * Returns a boolean.
  83 */
  84bool speakup_fake_key_pressed(void)
  85{
  86        return this_cpu_read(reporting_keystroke);
  87}
  88