// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  HID driver for Saitek devices.
 *
 *  PS1000 (USB gamepad):
 *  Fixes the HID report descriptor by removing a non-existent axis and
 *  clearing the constant bit on the input reports for buttons and d-pad.
 *  (This module is based on "hid-ortek".)
 *  Copyright (c) 2012 Andreas Hübner
 *
 *  R.A.T.7, R.A.T.9, M.M.O.7 (USB gaming mice):
 *  Fixes the mode button which cycles through three constantly pressed
 *  buttons. All three press events are mapped to one button and the
 *  missing release event is generated immediately.
 */

/*
 */

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

#include "hid-ids.h"

#define SAITEK_FIX_PS1000       0x0001
#define SAITEK_RELEASE_MODE_RAT7        0x0002
#define SAITEK_RELEASE_MODE_MMO7        0x0004

struct saitek_sc {
        unsigned long quirks;
        int mode;
};

static int saitek_probe(struct hid_device *hdev,
                const struct hid_device_id *id)
{
        unsigned long quirks = id->driver_data;
        struct saitek_sc *ssc;
        int ret;

        ssc = devm_kzalloc(&hdev->dev, sizeof(*ssc), GFP_KERNEL);
        if (ssc == NULL) {
                hid_err(hdev, "can't alloc saitek descriptor\n");
                return -ENOMEM;
        }

        ssc->quirks = quirks;
        ssc->mode = -1;

        hid_set_drvdata(hdev, ssc);

        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 __u8 *saitek_report_fixup(struct hid_device *hdev, __u8 *rdesc,
                unsigned int *rsize)
{
        struct saitek_sc *ssc = hid_get_drvdata(hdev);

        if ((ssc->quirks & SAITEK_FIX_PS1000) && *rsize == 137 &&
                        rdesc[20] == 0x09 && rdesc[21] == 0x33 &&
                        rdesc[94] == 0x81 && rdesc[95] == 0x03 &&
                        rdesc[110] == 0x81 && rdesc[111] == 0x03) {

                hid_info(hdev, "Fixing up Saitek PS1000 report descriptor\n");

                /* convert spurious axis to a "noop" Logical Minimum (0) */
                rdesc[20] = 0x15;
                rdesc[21] = 0x00;

                /* clear constant bit on buttons and d-pad */
                rdesc[95] = 0x02;
                rdesc[111] = 0x02;

        }
        return rdesc;
}

static int saitek_raw_event(struct hid_device *hdev,
                struct hid_report *report, u8 *raw_data, int size)
{
        struct saitek_sc *ssc = hid_get_drvdata(hdev);

        if (ssc->quirks & SAITEK_RELEASE_MODE_RAT7 && size == 7) {
                /* R.A.T.7 uses bits 13, 14, 15 for the mode */
                int mode = -1;
                if (raw_data[1] & 0x01)
                        mode = 0;
                else if (raw_data[1] & 0x02)
                        mode = 1;
                else if (raw_data[1] & 0x04)
                        mode = 2;

                /* clear mode bits */
                raw_data[1] &= ~0x07;

                if (mode != ssc->mode) {
                        hid_dbg(hdev, "entered mode %d\n", mode);
                        if (ssc->mode != -1) {
                                /* use bit 13 as the mode button */
                                raw_data[1] |= 0x04;
                        }
                        ssc->mode = mode;
                }
        } else if (ssc->quirks & SAITEK_RELEASE_MODE_MMO7 && size == 8) {

                /* M.M.O.7 uses bits 8, 22, 23 for the mode */
                int mode = -1;
                if (raw_data[1] & 0x80)
                        mode = 0;
                else if (raw_data[2] & 0x01)
                        mode = 1;
                else if (raw_data[2] & 0x02)
                        mode = 2;

                /* clear mode bits */
                raw_data[1] &= ~0x80;
                raw_data[2] &= ~0x03;

                if (mode != ssc->mode) {
                        hid_dbg(hdev, "entered mode %d\n", mode);
                        if (ssc->mode != -1) {
                                /* use bit 8 as the mode button, bits 22
                                 * and 23 do not represent buttons
                                 * according to the HID report descriptor
                                 */
                                raw_data[1] |= 0x80;
                        }
                        ssc->mode = mode;
                }
        }

        return 0;
}

static int saitek_event(struct hid_device *hdev, struct hid_field *field,
                struct hid_usage *usage, __s32 value)
{
        struct saitek_sc *ssc = hid_get_drvdata(hdev);
        struct input_dev *input = field->hidinput->input;

        if (usage->type == EV_KEY && value &&
                        (((ssc->quirks & SAITEK_RELEASE_MODE_RAT7) &&
                          usage->code - BTN_MOUSE == 10) ||
                        ((ssc->quirks & SAITEK_RELEASE_MODE_MMO7) &&
                         usage->code - BTN_MOUSE == 15))) {

                input_report_key(input, usage->code, 1);

                /* report missing release event */
                input_report_key(input, usage->code, 0);

                return 1;
        }

        return 0;
}

static const struct hid_device_id saitek_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_PS1000),
                .driver_data = SAITEK_FIX_PS1000 },
        { HID_USB_DEVICE(USB_VENDOR_ID_MADCATZ, USB_DEVICE_ID_MADCATZ_RAT5),
                .driver_data = SAITEK_RELEASE_MODE_RAT7 },
        { HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_RAT7_OLD),
                .driver_data = SAITEK_RELEASE_MODE_RAT7 },
        { HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_RAT7),
                .driver_data = SAITEK_RELEASE_MODE_RAT7 },
        { HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_RAT7_CONTAGION),
                .driver_data = SAITEK_RELEASE_MODE_RAT7 },
        { HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_RAT9),
                .driver_data = SAITEK_RELEASE_MODE_RAT7 },
        { HID_USB_DEVICE(USB_VENDOR_ID_MADCATZ, USB_DEVICE_ID_MADCATZ_RAT9),
                .driver_data = SAITEK_RELEASE_MODE_RAT7 },
        { HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_MMO7),
                .driver_data = SAITEK_RELEASE_MODE_MMO7 },
        { HID_USB_DEVICE(USB_VENDOR_ID_MADCATZ, USB_DEVICE_ID_MADCATZ_MMO7),
                .driver_data = SAITEK_RELEASE_MODE_MMO7 },
        { }
};

MODULE_DEVICE_TABLE(hid, saitek_devices);

static struct hid_driver saitek_driver = {
        .name = "saitek",
        .id_table = saitek_devices,
        .probe = saitek_probe,
        .report_fixup = saitek_report_fixup,
        .raw_event = saitek_raw_event,
        .event = saitek_event,
};
module_hid_driver(saitek_driver);

MODULE_DESCRIPTION("HID driver for Saitek devices.");
MODULE_LICENSE("GPL");