ams-input.c

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/*
 * Apple Motion Sensor driver (joystick emulation)
 *
 * Copyright (C) 2005 Stelian Pop ([email protected])
 * Copyright (C) 2006 Michael Hanselmann ([email protected])
 *
 * 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.
 */

#include <linux/module.h>

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/delay.h>

#include "ams.h"

static bool joystick;
module_param(joystick, bool, S_IRUGO);
MODULE_PARM_DESC(joystick, "Enable the input class device on module load");

static bool invert;
module_param(invert, bool, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(invert, "Invert input data on X and Y axis");

static DEFINE_MUTEX(ams_input_mutex);

static void ams_idev_poll(struct input_polled_dev *dev)
{
    struct input_dev *idev = dev->input;
    s8 x, y, z;

    mutex_lock(&ams_info.lock);

    ams_sensors(&x, &y, &z);

    x -= ams_info.xcalib;
    y -= ams_info.ycalib;
    z -= ams_info.zcalib;

    input_report_abs(idev, ABS_X, invert ? -x : x);
    input_report_abs(idev, ABS_Y, invert ? -y : y);
    input_report_abs(idev, ABS_Z, z);

    input_sync(idev);

    mutex_unlock(&ams_info.lock);
}

/* Call with ams_info.lock held! */
static int ams_input_enable(void)
{
    struct input_dev *input;
    s8 x, y, z;
    int error;

    ams_sensors(&x, &y, &z);
    ams_info.xcalib = x;
    ams_info.ycalib = y;
    ams_info.zcalib = z;

    ams_info.idev = input_allocate_polled_device();
    if (!ams_info.idev)
        return -ENOMEM;

    ams_info.idev->poll = ams_idev_poll;
    ams_info.idev->poll_interval = 25;

    input = ams_info.idev->input;
    input->name = "Apple Motion Sensor";
    input->id.bustype = ams_info.bustype;
    input->id.vendor = 0;
    input->dev.parent = &ams_info.of_dev->dev;

    input_set_abs_params(input, ABS_X, -50, 50, 3, 0);
    input_set_abs_params(input, ABS_Y, -50, 50, 3, 0);
    input_set_abs_params(input, ABS_Z, -50, 50, 3, 0);

    set_bit(EV_ABS, input->evbit);
    set_bit(EV_KEY, input->evbit);
    set_bit(BTN_TOUCH, input->keybit);

    error = input_register_polled_device(ams_info.idev);
    if (error) {
        input_free_polled_device(ams_info.idev);
        ams_info.idev = NULL;
        return error;
    }

    joystick = 1;

    return 0;
}

static void ams_input_disable(void)
{
    if (ams_info.idev) {
        input_unregister_polled_device(ams_info.idev);
        input_free_polled_device(ams_info.idev);
        ams_info.idev = NULL;
    }

    joystick = 0;
}

static ssize_t ams_input_show_joystick(struct device *dev,
    struct device_attribute *attr, char *buf)
{
    return sprintf(buf, "%d\n", joystick);
}

static ssize_t ams_input_store_joystick(struct device *dev,
    struct device_attribute *attr, const char *buf, size_t count)
{
    unsigned long enable;
    int error = 0;

    if (strict_strtoul(buf, 0, &enable) || enable > 1)
        return -EINVAL;

    mutex_lock(&ams_input_mutex);

    if (enable != joystick) {
        if (enable)
            error = ams_input_enable();
        else
            ams_input_disable();
    }

    mutex_unlock(&ams_input_mutex);

    return error ? error : count;
}

static DEVICE_ATTR(joystick, S_IRUGO | S_IWUSR,
    ams_input_show_joystick, ams_input_store_joystick);

int ams_input_init(void)
{
    if (joystick)
        ams_input_enable();

    return device_create_file(&ams_info.of_dev->dev, &dev_attr_joystick);
}

void ams_input_exit(void)
{
    device_remove_file(&ams_info.of_dev->dev, &dev_attr_joystick);

    mutex_lock(&ams_input_mutex);
    ams_input_disable();
    mutex_unlock(&ams_input_mutex);
}