drivers/staging/speakup/fakekey.c

   1 /* fakekey.c
   2  * Functions for simulating keypresses.
   3  *
   4  * Copyright (C) 2010 the Speakup Team
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16 #include <linux/types.h>
  17 #include <linux/slab.h>
  18 #include <linux/preempt.h>
  19 #include <linux/percpu.h>
  20 #include <linux/input.h>
  21
  22 #include "speakup.h"
  23
  24 #define PRESSED 1
  25 #define RELEASED 0
  26
  27 static DEFINE_PER_CPU(int, reporting_keystroke);
  28
  29 static struct input_dev *virt_keyboard;
  30
  31 int speakup_add_virtual_keyboard(void)
  32 {
  33         int err;
  34
  35         virt_keyboard = input_allocate_device();
  36
  37         if (!virt_keyboard)
  38                 return -ENOMEM;
  39
  40         virt_keyboard->name = "Speakup";
  41         virt_keyboard->id.bustype = BUS_VIRTUAL;
  42         virt_keyboard->phys = "speakup/input0";
  43         virt_keyboard->dev.parent = NULL;
  44
  45         __set_bit(EV_KEY, virt_keyboard->evbit);
  46         __set_bit(KEY_DOWN, virt_keyboard->keybit);
  47
  48         err = input_register_device(virt_keyboard);
  49         if (err) {
  50                 input_free_device(virt_keyboard);
  51                 virt_keyboard = NULL;
  52         }
  53
  54         return err;
  55 }
  56
  57 void speakup_remove_virtual_keyboard(void)
  58 {
  59         if (virt_keyboard != NULL) {
  60                 input_unregister_device(virt_keyboard);
  61                 virt_keyboard = NULL;
  62         }
  63 }
  64
  65 /*
  66          * Send a simulated down-arrow to the application.
  67          */
  68 void speakup_fake_down_arrow(void)
  69 {
  70         unsigned long flags;
  71
  72         /* disable keyboard interrupts */
  73         local_irq_save(flags);
  74         /* don't change CPU */
  75         preempt_disable();
  76
  77         __this_cpu_write(reporting_keystroke, true);
  78         input_report_key(virt_keyboard, KEY_DOWN, PRESSED);
  79         input_report_key(virt_keyboard, KEY_DOWN, RELEASED);
  80         input_sync(virt_keyboard);
  81         __this_cpu_write(reporting_keystroke, false);
  82
  83         /* reenable preemption */
  84         preempt_enable();
  85         /* reenable keyboard interrupts */
  86         local_irq_restore(flags);
  87 }
  88
  89 /*
  90          * Are we handling a simulated keypress on the current CPU?
  91          * Returns a boolean.
  92          */
  93 bool speakup_fake_key_pressed(void)
  94 {
  95         return this_cpu_read(reporting_keystroke);
  96 }