// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Stadia controller rumble support.
 *
 * Copyright 2023 Google LLC
 */

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

#include "hid-ids.h"

#define STADIA_FF_REPORT_ID 5

struct stadiaff_device {
        struct hid_device *hid;
        struct hid_report *report;
        spinlock_t lock;
        bool removed;
        uint16_t strong_magnitude;
        uint16_t weak_magnitude;
        struct work_struct work;
};

static void stadiaff_work(struct work_struct *work)
{
        struct stadiaff_device *stadiaff =
                container_of(work, struct stadiaff_device, work);
        struct hid_field *rumble_field = stadiaff->report->field[0];
        unsigned long flags;

        spin_lock_irqsave(&stadiaff->lock, flags);
        rumble_field->value[0] = stadiaff->strong_magnitude;
        rumble_field->value[1] = stadiaff->weak_magnitude;
        spin_unlock_irqrestore(&stadiaff->lock, flags);

        hid_hw_request(stadiaff->hid, stadiaff->report, HID_REQ_SET_REPORT);
}

static int stadiaff_play(struct input_dev *dev, void *data,
                         struct ff_effect *effect)
{
        struct hid_device *hid = input_get_drvdata(dev);
        struct stadiaff_device *stadiaff = hid_get_drvdata(hid);
        unsigned long flags;

        spin_lock_irqsave(&stadiaff->lock, flags);
        if (!stadiaff->removed) {
                stadiaff->strong_magnitude = effect->u.rumble.strong_magnitude;
                stadiaff->weak_magnitude = effect->u.rumble.weak_magnitude;
                schedule_work(&stadiaff->work);
        }
        spin_unlock_irqrestore(&stadiaff->lock, flags);

        return 0;
}

static int stadiaff_init(struct hid_device *hid)
{
        struct stadiaff_device *stadiaff;
        struct hid_report *report;
        struct hid_input *hidinput;
        struct input_dev *dev;
        int error;

        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;

        report = hid_validate_values(hid, HID_OUTPUT_REPORT,
                                     STADIA_FF_REPORT_ID, 0, 2);
        if (!report)
                return -ENODEV;

        stadiaff = devm_kzalloc(&hid->dev, sizeof(struct stadiaff_device),
                                GFP_KERNEL);
        if (!stadiaff)
                return -ENOMEM;

        hid_set_drvdata(hid, stadiaff);

        input_set_capability(dev, EV_FF, FF_RUMBLE);

        error = input_ff_create_memless(dev, NULL, stadiaff_play);
        if (error)
                return error;

        stadiaff->removed = false;
        stadiaff->hid = hid;
        stadiaff->report = report;
        INIT_WORK(&stadiaff->work, stadiaff_work);
        spin_lock_init(&stadiaff->lock);

        hid_info(hid, "Force Feedback for Google Stadia controller\n");

        return 0;
}

static int stadia_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 = stadiaff_init(hdev);
        if (ret) {
                hid_err(hdev, "force feedback init failed\n");
                hid_hw_stop(hdev);
                return ret;
        }

        return 0;
}

static void stadia_remove(struct hid_device *hid)
{
        struct stadiaff_device *stadiaff = hid_get_drvdata(hid);
        unsigned long flags;

        spin_lock_irqsave(&stadiaff->lock, flags);
        stadiaff->removed = true;
        spin_unlock_irqrestore(&stadiaff->lock, flags);

        cancel_work_sync(&stadiaff->work);
        hid_hw_stop(hid);
}

static const struct hid_device_id stadia_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STADIA) },
        { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STADIA) },
        { }
};
MODULE_DEVICE_TABLE(hid, stadia_devices);

static struct hid_driver stadia_driver = {
        .name = "stadia",
        .id_table = stadia_devices,
        .probe = stadia_probe,
        .remove = stadia_remove,
};
module_hid_driver(stadia_driver);

MODULE_DESCRIPTION("Google Stadia controller rumble support.");
MODULE_LICENSE("GPL");