// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Vibration support for Mega World controllers
 *
 * Copyright 2022 Frank Zago
 *
 * Derived from hid-zpff.c:
 *   Copyright (c) 2005, 2006 Anssi Hannula <anssi.hannula@gmail.com>
 */

#include <linux/hid.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "hid-ids.h"

struct mwctrl_device {
        struct hid_report *report;
        s32 *weak;
        s32 *strong;
};

static int mwctrl_play(struct input_dev *dev, void *data,
                       struct ff_effect *effect)
{
        struct hid_device *hid = input_get_drvdata(dev);
        struct mwctrl_device *mwctrl = data;

        *mwctrl->strong = effect->u.rumble.strong_magnitude >> 8;
        *mwctrl->weak = effect->u.rumble.weak_magnitude >> 8;

        hid_hw_request(hid, mwctrl->report, HID_REQ_SET_REPORT);

        return 0;
}

static int mwctrl_init(struct hid_device *hid)
{
        struct mwctrl_device *mwctrl;
        struct hid_report *report;
        struct hid_input *hidinput;
        struct input_dev *dev;
        int error;
        int i;

        if (list_empty(&hid->inputs)) {
                hid_err(hid, "no inputs found\n");
                return -ENODEV;
        }
        hidinput = list_entry(hid->inputs.next, struct hid_input, list);
        dev = hidinput->input;

        for (i = 0; i < 4; i++) {
                report = hid_validate_values(hid, HID_OUTPUT_REPORT, 0, i, 1);
                if (!report)
                        return -ENODEV;
        }

        mwctrl = kzalloc_obj(struct mwctrl_device);
        if (!mwctrl)
                return -ENOMEM;

        set_bit(FF_RUMBLE, dev->ffbit);

        error = input_ff_create_memless(dev, mwctrl, mwctrl_play);
        if (error) {
                kfree(mwctrl);
                return error;
        }

        mwctrl->report = report;

        /* Field 0 is always 2, and field 1 is always 0. The original
         * windows driver has a 5 bytes command, where the 5th byte is
         * a repeat of the 3rd byte, however the device has only 4
         * fields. It could be a bug in the driver, or there is a
         * different device that needs it.
         */
        report->field[0]->value[0] = 0x02;

        mwctrl->strong = &report->field[2]->value[0];
        mwctrl->weak = &report->field[3]->value[0];

        return 0;
}

static int mwctrl_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
        int ret;

        ret = hid_parse(hdev);
        if (ret) {
                hid_err(hdev, "parse failed\n");
                return ret;
        }

        ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
        if (ret) {
                hid_err(hdev, "hw start failed\n");
                return ret;
        }

        ret = mwctrl_init(hdev);
        if (ret)
                hid_hw_stop(hdev);

        return ret;
}

static const struct hid_device_id mwctrl_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_MEGAWORLD,
                         USB_DEVICE_ID_MEGAWORLD_GAMEPAD) },
        { }
};
MODULE_DEVICE_TABLE(hid, mwctrl_devices);

static struct hid_driver mwctrl_driver = {
        .name = "megaworld",
        .id_table = mwctrl_devices,
        .probe = mwctrl_probe,
};
module_hid_driver(mwctrl_driver);

MODULE_DESCRIPTION("Vibration support for Mega World controllers");
MODULE_LICENSE("GPL");