// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * HID driver for PhoenixRC 8-axis flight controller
 *
 * Copyright (C) 2022 Marcus Folkesson <marcus.folkesson@gmail.com>
 */

#include <linux/device.h>
#include <linux/hid.h>
#include <linux/module.h>

#include "hid-ids.h"

struct pxrc_priv {
        u8 slider;
        u8 dial;
        bool alternate;
};

static const __u8 pxrc_rdesc_fixed[] = {
        0x05, 0x01,        // Usage Page (Generic Desktop Ctrls)
        0x09, 0x04,        // Usage (Joystick)
        0xA1, 0x01,        // Collection (Application)
        0x09, 0x01,        //   Usage (Pointer)
        0xA1, 0x00,        //   Collection (Physical)
        0x09, 0x30,        //     Usage (X)
        0x09, 0x36,        //     Usage (Slider)
        0x09, 0x31,        //     Usage (Y)
        0x09, 0x32,        //     Usage (Z)
        0x09, 0x33,        //     Usage (Rx)
        0x09, 0x34,        //     Usage (Ry)
        0x09, 0x35,        //     Usage (Rz)
        0x09, 0x37,        //     Usage (Dial)
        0x15, 0x00,        //     Logical Minimum (0)
        0x26, 0xFF, 0x00,  //     Logical Maximum (255)
        0x35, 0x00,        //     Physical Minimum (0)
        0x46, 0xFF, 0x00,  //     Physical Maximum (255)
        0x75, 0x08,        //     Report Size (8)
        0x95, 0x08,        //     Report Count (8)
        0x81, 0x02,        //     Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
        0xC0,              //   End Collection
        0xC0,              // End Collection
};

static const __u8 *pxrc_report_fixup(struct hid_device *hdev, __u8 *rdesc,
                                     unsigned int *rsize)
{
        hid_info(hdev, "fixing up PXRC report descriptor\n");
        *rsize = sizeof(pxrc_rdesc_fixed);
        return pxrc_rdesc_fixed;
}

static int pxrc_raw_event(struct hid_device *hdev, struct hid_report *report,
         u8 *data, int size)
{
        struct pxrc_priv *priv = hid_get_drvdata(hdev);

        if (priv->alternate)
                priv->slider = data[7];
        else
                priv->dial = data[7];

        data[1] = priv->slider;
        data[7] = priv->dial;

        priv->alternate = !priv->alternate;
        return 0;
}

static int pxrc_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
        int ret;
        struct pxrc_priv *priv;

        priv = devm_kzalloc(&hdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
        hid_set_drvdata(hdev, priv);

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

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

        return 0;
}

static const struct hid_device_id pxrc_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_MULTIPLE_1781, USB_DEVICE_ID_PHOENIXRC) },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(hid, pxrc_devices);

static struct hid_driver pxrc_driver = {
        .name = "hid-pxrc",
        .id_table = pxrc_devices,
        .report_fixup = pxrc_report_fixup,
        .probe = pxrc_probe,
        .raw_event = pxrc_raw_event,
};
module_hid_driver(pxrc_driver);

MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
MODULE_DESCRIPTION("HID driver for PXRC 8-axis flight controller");
MODULE_LICENSE("GPL");