fakekey.c

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/* fakekey.c
 * Functions for simulating keypresses.
 *
 * Copyright (C) 2010 the Speakup Team
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/preempt.h>
#include <linux/percpu.h>
#include <linux/input.h>

#include "speakup.h"

#define PRESSED 1
#define RELEASED 0

DEFINE_PER_CPU(bool, reporting_keystroke);

static struct input_dev *virt_keyboard;

int speakup_add_virtual_keyboard(void)
{
    int err;

    virt_keyboard = input_allocate_device();

    if (!virt_keyboard)
        return -ENOMEM;

    virt_keyboard->name = "Speakup";
    virt_keyboard->id.bustype = BUS_VIRTUAL;
    virt_keyboard->phys = "speakup/input0";
    virt_keyboard->dev.parent = NULL;

    __set_bit(EV_KEY, virt_keyboard->evbit);
    __set_bit(KEY_DOWN, virt_keyboard->keybit);

    err = input_register_device(virt_keyboard);
    if (err) {
        input_free_device(virt_keyboard);
        virt_keyboard = NULL;
    }

    return err;
}

void speakup_remove_virtual_keyboard(void)
{
    if (virt_keyboard != NULL) {
        input_unregister_device(virt_keyboard);
        virt_keyboard = NULL;
    }
}

/*
     * Send a simulated down-arrow to the application.
     */
void speakup_fake_down_arrow(void)
{
    unsigned long flags;

    /* disable keyboard interrupts */
    local_irq_save(flags);
    /* don't change CPU */
    preempt_disable();

    __this_cpu_write(reporting_keystroke, true);
    input_report_key(virt_keyboard, KEY_DOWN, PRESSED);
    input_report_key(virt_keyboard, KEY_DOWN, RELEASED);
    __this_cpu_write(reporting_keystroke, false);

    /* reenable preemption */
    preempt_enable();
    /* reenable keyboard interrupts */
    local_irq_restore(flags);
}

/*
     * Are we handling a simulated keypress on the current CPU?
     * Returns a boolean.
     */
bool speakup_fake_key_pressed(void)
{
    return this_cpu_read(reporting_keystroke);
}