// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Apple Motion Sensor driver (joystick emulation)
 *
 * Copyright (C) 2005 Stelian Pop (stelian@popies.net)
 * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
 */

#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_dev *idev)
{
        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;

        input = input_allocate_device();
        if (!input)
                return -ENOMEM;

        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);
        input_set_capability(input, EV_KEY, BTN_TOUCH);

        error = input_setup_polling(input, ams_idev_poll);
        if (error)
                goto err_free_input;

        input_set_poll_interval(input, 25);

        error = input_register_device(input);
        if (error)
                goto err_free_input;

        ams_info.idev = input;
        joystick = true;

        return 0;

err_free_input:
        input_free_device(input);
        return error;
}

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

        joystick = false;
}

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;
        int ret;

        ret = kstrtoul(buf, 0, &enable);
        if (ret)
                return ret;
        if (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);
}