/*
 * Force feedback support for DragonRise Inc. game controllers
 *
 * From what I have gathered, these devices are mass produced in China and are
 * distributed under several vendors. They often share the same design as
 * the original PlayStation DualShock controller.
 *
 * 0079:0006 "DragonRise Inc.   Generic   USB  Joystick  "
 *  - tested with a Tesun USB-703 game controller.
 *
 * Copyright (c) 2009 Richard Walmsley <richwalm@gmail.com>
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

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

#include "hid-ids.h"

#ifdef CONFIG_DRAGONRISE_FF
#include "usbhid/usbhid.h"

struct drff_device {
        struct hid_report *report;
};

static int drff_play(struct input_dev *dev, void *data,
                                 struct ff_effect *effect)
{
        struct hid_device *hid = input_get_drvdata(dev);
        struct drff_device *drff = data;
        int strong, weak;

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

        dbg_hid("called with 0x%04x 0x%04x", strong, weak);

        if (strong || weak) {
                strong = strong * 0xff / 0xffff;
                weak = weak * 0xff / 0xffff;

                /* While reverse engineering this device, I found that when
                   this value is set, it causes the strong rumble to function
                   at a near maximum speed, so we'll bypass it. */
                if (weak == 0x0a)
                        weak = 0x0b;

                drff->report->field[0]->value[0] = 0x51;
                drff->report->field[0]->value[1] = 0x00;
                drff->report->field[0]->value[2] = weak;
                drff->report->field[0]->value[4] = strong;
                usbhid_submit_report(hid, drff->report, USB_DIR_OUT);

                drff->report->field[0]->value[0] = 0xfa;
                drff->report->field[0]->value[1] = 0xfe;
        } else {
                drff->report->field[0]->value[0] = 0xf3;
                drff->report->field[0]->value[1] = 0x00;
        }

        drff->report->field[0]->value[2] = 0x00;
        drff->report->field[0]->value[4] = 0x00;
        dbg_hid("running with 0x%02x 0x%02x", strong, weak);
        usbhid_submit_report(hid, drff->report, USB_DIR_OUT);

        return 0;
}

static int drff_init(struct hid_device *hid)
{
        struct drff_device *drff;
        struct hid_report *report;
        struct hid_input *hidinput = list_first_entry(&hid->inputs,
                                                struct hid_input, list);
        struct list_head *report_list =
                        &hid->report_enum[HID_OUTPUT_REPORT].report_list;
        struct input_dev *dev = hidinput->input;
        int error;

        if (list_empty(report_list)) {
                hid_err(hid, "no output reports found\n");
                return -ENODEV;
        }

        report = list_first_entry(report_list, struct hid_report, list);
        if (report->maxfield < 1) {
                hid_err(hid, "no fields in the report\n");
                return -ENODEV;
        }

        if (report->field[0]->report_count < 7) {
                hid_err(hid, "not enough values in the field\n");
                return -ENODEV;
        }

        drff = kzalloc(sizeof(struct drff_device), GFP_KERNEL);
        if (!drff)
                return -ENOMEM;

        set_bit(FF_RUMBLE, dev->ffbit);

        error = input_ff_create_memless(dev, drff, drff_play);
        if (error) {
                kfree(drff);
                return error;
        }

        drff->report = report;
        drff->report->field[0]->value[0] = 0xf3;
        drff->report->field[0]->value[1] = 0x00;
        drff->report->field[0]->value[2] = 0x00;
        drff->report->field[0]->value[3] = 0x00;
        drff->report->field[0]->value[4] = 0x00;
        drff->report->field[0]->value[5] = 0x00;
        drff->report->field[0]->value[6] = 0x00;
        usbhid_submit_report(hid, drff->report, USB_DIR_OUT);

        hid_info(hid, "Force Feedback for DragonRise Inc. "
                 "game controllers by Richard Walmsley <richwalm@gmail.com>\n");

        return 0;
}
#else
static inline int drff_init(struct hid_device *hid)
{
        return 0;
}
#endif

/*
 * The original descriptor of joystick with PID 0x0011, represented by DVTech PC
 * JS19. It seems both copied from another device and a result of confusion
 * either about the specification or about the program used to create the
 * descriptor. In any case, it's a wonder it works on Windows.
 *
 *  Usage Page (Desktop),             ; Generic desktop controls (01h)
 *  Usage (Joystik),                  ; Joystik (04h, application collection)
 *  Collection (Application),
 *    Collection (Logical),
 *      Report Size (8),
 *      Report Count (5),
 *      Logical Minimum (0),
 *      Logical Maximum (255),
 *      Physical Minimum (0),
 *      Physical Maximum (255),
 *      Usage (X),                    ; X (30h, dynamic value)
 *      Usage (X),                    ; X (30h, dynamic value)
 *      Usage (X),                    ; X (30h, dynamic value)
 *      Usage (X),                    ; X (30h, dynamic value)
 *      Usage (Y),                    ; Y (31h, dynamic value)
 *      Input (Variable),
 *      Report Size (4),
 *      Report Count (1),
 *      Logical Maximum (7),
 *      Physical Maximum (315),
 *      Unit (Degrees),
 *      Usage (00h),
 *      Input (Variable, Null State),
 *      Unit,
 *      Report Size (1),
 *      Report Count (10),
 *      Logical Maximum (1),
 *      Physical Maximum (1),
 *      Usage Page (Button),          ; Button (09h)
 *      Usage Minimum (01h),
 *      Usage Maximum (0Ah),
 *      Input (Variable),
 *      Usage Page (FF00h),           ; FF00h, vendor-defined
 *      Report Size (1),
 *      Report Count (10),
 *      Logical Maximum (1),
 *      Physical Maximum (1),
 *      Usage (01h),
 *      Input (Variable),
 *    End Collection,
 *    Collection (Logical),
 *      Report Size (8),
 *      Report Count (4),
 *      Physical Maximum (255),
 *      Logical Maximum (255),
 *      Usage (02h),
 *      Output (Variable),
 *    End Collection,
 *  End Collection
 */

/* Size of the original descriptor of the PID 0x0011 joystick */
#define PID0011_RDESC_ORIG_SIZE 101

/* Fixed report descriptor for PID 0x011 joystick */
static __u8 pid0011_rdesc_fixed[] = {
        0x05, 0x01,         /*  Usage Page (Desktop),           */
        0x09, 0x04,         /*  Usage (Joystik),                */
        0xA1, 0x01,         /*  Collection (Application),       */
        0xA1, 0x02,         /*      Collection (Logical),       */
        0x14,               /*          Logical Minimum (0),    */
        0x75, 0x08,         /*          Report Size (8),        */
        0x95, 0x03,         /*          Report Count (3),       */
        0x81, 0x01,         /*          Input (Constant),       */
        0x26, 0xFF, 0x00,   /*          Logical Maximum (255),  */
        0x95, 0x02,         /*          Report Count (2),       */
        0x09, 0x30,         /*          Usage (X),              */
        0x09, 0x31,         /*          Usage (Y),              */
        0x81, 0x02,         /*          Input (Variable),       */
        0x75, 0x01,         /*          Report Size (1),        */
        0x95, 0x04,         /*          Report Count (4),       */
        0x81, 0x01,         /*          Input (Constant),       */
        0x25, 0x01,         /*          Logical Maximum (1),    */
        0x95, 0x0A,         /*          Report Count (10),      */
        0x05, 0x09,         /*          Usage Page (Button),    */
        0x19, 0x01,         /*          Usage Minimum (01h),    */
        0x29, 0x0A,         /*          Usage Maximum (0Ah),    */
        0x81, 0x02,         /*          Input (Variable),       */
        0x95, 0x0A,         /*          Report Count (10),      */
        0x81, 0x01,         /*          Input (Constant),       */
        0xC0,               /*      End Collection,             */
        0xC0                /*  End Collection                  */
};

static __u8 *dr_report_fixup(struct hid_device *hdev, __u8 *rdesc,
                                unsigned int *rsize)
{
        switch (hdev->product) {
        case 0x0011:
                if (*rsize == PID0011_RDESC_ORIG_SIZE) {
                        rdesc = pid0011_rdesc_fixed;
                        *rsize = sizeof(pid0011_rdesc_fixed);
                }
                break;
        }
        return rdesc;
}

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

        dev_dbg(&hdev->dev, "DragonRise Inc. HID hardware probe...");

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

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

        switch (hdev->product) {
        case 0x0006:
                ret = drff_init(hdev);
                if (ret) {
                        dev_err(&hdev->dev, "force feedback init failed\n");
                        hid_hw_stop(hdev);
                        goto err;
                }
                break;
        }

        return 0;
err:
        return ret;
}

static const struct hid_device_id dr_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, 0x0006),  },
        { HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, 0x0011),  },
        { }
};
MODULE_DEVICE_TABLE(hid, dr_devices);

static struct hid_driver dr_driver = {
        .name = "dragonrise",
        .id_table = dr_devices,
        .report_fixup = dr_report_fixup,
        .probe = dr_probe,
};

static int __init dr_init(void)
{
        return hid_register_driver(&dr_driver);
}

static void __exit dr_exit(void)
{
        hid_unregister_driver(&dr_driver);
}

module_init(dr_init);
module_exit(dr_exit);
MODULE_LICENSE("GPL");