root/drivers/hid/hid-glorious.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  USB HID driver for Glorious PC Gaming Race
 *  Glorious Model O, O- and D mice.
 *
 *  Copyright (c) 2020 Samuel Čavoj <sammko@sammserver.com>
 */

/*
 */

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

#include "hid-ids.h"

MODULE_AUTHOR("Samuel Čavoj <sammko@sammserver.com>");
MODULE_DESCRIPTION("HID driver for Glorious PC Gaming Race mice");

/*
 * Glorious Model O and O- specify the const flag in the consumer input
 * report descriptor, which leads to inputs being ignored. Fix this
 * by patching the descriptor.
 *
 * Glorious Model I incorrectly specifes the Usage Minimum for its
 * keyboard HID report, causing keycodes to be misinterpreted.
 * Fix this by setting Usage Minimum to 0 in that report.
 */
static const __u8 *glorious_report_fixup(struct hid_device *hdev, __u8 *rdesc,
                unsigned int *rsize)
{
        if (*rsize == 213 &&
                rdesc[84] == 129 && rdesc[112] == 129 && rdesc[140] == 129 &&
                rdesc[85] == 3   && rdesc[113] == 3   && rdesc[141] == 3) {
                hid_info(hdev, "patching Glorious Model O consumer control report descriptor\n");
                rdesc[85] = rdesc[113] = rdesc[141] = \
                        HID_MAIN_ITEM_VARIABLE | HID_MAIN_ITEM_RELATIVE;
        }
        if (*rsize == 156 && rdesc[41] == 1) {
                hid_info(hdev, "patching Glorious Model I keyboard report descriptor\n");
                rdesc[41] = 0;
        }
        return rdesc;
}

static void glorious_update_name(struct hid_device *hdev)
{
        const char *model = "Device";

        switch (hdev->product) {
        case USB_DEVICE_ID_GLORIOUS_MODEL_O:
                model = "Model O"; break;
        case USB_DEVICE_ID_GLORIOUS_MODEL_D:
                model = "Model D"; break;
        case USB_DEVICE_ID_GLORIOUS_MODEL_I:
                model = "Model I"; break;
        }

        snprintf(hdev->name, sizeof(hdev->name), "%s %s", "Glorious", model);
}

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

        hdev->quirks |= HID_QUIRK_INPUT_PER_APP;

        ret = hid_parse(hdev);
        if (ret)
                return ret;

        glorious_update_name(hdev);

        return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
}

static const struct hid_device_id glorious_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_SINOWEALTH,
                USB_DEVICE_ID_GLORIOUS_MODEL_O) },
        { HID_USB_DEVICE(USB_VENDOR_ID_SINOWEALTH,
                USB_DEVICE_ID_GLORIOUS_MODEL_D) },
        { HID_USB_DEVICE(USB_VENDOR_ID_LAVIEW,
                USB_DEVICE_ID_GLORIOUS_MODEL_I) },
        { }
};
MODULE_DEVICE_TABLE(hid, glorious_devices);

static struct hid_driver glorious_driver = {
        .name = "glorious",
        .id_table = glorious_devices,
        .probe = glorious_probe,
        .report_fixup = glorious_report_fixup
};

module_hid_driver(glorious_driver);

MODULE_LICENSE("GPL");