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  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <linux/types.h>
  21 #include <linux/slab.h>
  22 #include <linux/preempt.h>
  23 #include <linux/percpu.h>
  24 #include <linux/input.h>
  25
  26 #include "speakup.h"
  27
  28 #define PRESSED 1
  29 #define RELEASED 0
  30
  31 DEFINE_PER_CPU(bool, reporting_keystroke);
  32
  33 static struct input_dev *virt_keyboard;
  34
  35 int speakup_add_virtual_keyboard(void)
  36 {
  37         int err;
  38
  39         virt_keyboard = input_allocate_device();
  40
  41         if (!virt_keyboard)
  42                 return -ENOMEM;
  43
  44         virt_keyboard->name = "Speakup";
  45         virt_keyboard->id.bustype = BUS_VIRTUAL;
  46         virt_keyboard->phys = "speakup/input0";
  47         virt_keyboard->dev.parent = NULL;
  48
  49         __set_bit(EV_KEY, virt_keyboard->evbit);
  50         __set_bit(KEY_DOWN, virt_keyboard->keybit);
  51
  52         err = input_register_device(virt_keyboard);
  53         if (err) {
  54                 input_free_device(virt_keyboard);
  55                 virt_keyboard = NULL;
  56         }
  57
  58         return err;
  59 }
  60
  61 void speakup_remove_virtual_keyboard(void)
  62 {
  63         if (virt_keyboard != NULL) {
  64                 input_unregister_device(virt_keyboard);
  65                 input_free_device(virt_keyboard);
  66                 virt_keyboard = NULL;
  67         }
  68 }
  69
  70 /*
  71          * Send a simulated down-arrow to the application.
  72          */
  73 void speakup_fake_down_arrow(void)
  74 {
  75         unsigned long flags;
  76
  77         /* disable keyboard interrupts */
  78         local_irq_save(flags);
  79         /* don't change CPU */
  80         preempt_disable();
  81
  82         __get_cpu_var(reporting_keystroke) = true;
  83         input_report_key(virt_keyboard, KEY_DOWN, PRESSED);
  84         input_report_key(virt_keyboard, KEY_DOWN, RELEASED);
  85         __get_cpu_var(reporting_keystroke) = false;
  86
  87         /* reenable preemption */
  88         preempt_enable();
  89         /* reenable keyboard interrupts */
  90         local_irq_restore(flags);
  91 }
  92
  93 /*
  94          * Are we handling a simulated keypress on the current CPU?
  95          * Returns a boolean.
  96          */
  97 bool speakup_fake_key_pressed(void)
  98 {
  99         bool is_pressed;
 100
 101         is_pressed = get_cpu_var(reporting_keystroke);
 102         put_cpu_var(reporting_keystroke);
 103
 104         return is_pressed;
 105 }