/*
 *   Apple "Magic" Wireless Mouse driver
 *
 *   Copyright (c) 2010 Michael Poole <mdpoole@troilus.org>
 *   Copyright (c) 2010 Chase Douglas <chase.douglas@canonical.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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#include "hid-ids.h"

static bool emulate_3button = true;
module_param(emulate_3button, bool, 0644);
MODULE_PARM_DESC(emulate_3button, "Emulate a middle button");

static int middle_button_start = -350;
static int middle_button_stop = +350;

static bool emulate_scroll_wheel = true;
module_param(emulate_scroll_wheel, bool, 0644);
MODULE_PARM_DESC(emulate_scroll_wheel, "Emulate a scroll wheel");

static unsigned int scroll_speed = 32;
static int param_set_scroll_speed(const char *val, struct kernel_param *kp) {
        unsigned long speed;
        if (!val || strict_strtoul(val, 0, &speed) || speed > 63)
                return -EINVAL;
        scroll_speed = speed;
        return 0;
}
module_param_call(scroll_speed, param_set_scroll_speed, param_get_uint, &scroll_speed, 0644);
MODULE_PARM_DESC(scroll_speed, "Scroll speed, value from 0 (slow) to 63 (fast)");

static bool scroll_acceleration = false;
module_param(scroll_acceleration, bool, 0644);
MODULE_PARM_DESC(scroll_acceleration, "Accelerate sequential scroll events");

static bool report_touches = true;
module_param(report_touches, bool, 0644);
MODULE_PARM_DESC(report_touches, "Emit touch records (otherwise, only use them for emulation)");

static bool report_undeciphered;
module_param(report_undeciphered, bool, 0644);
MODULE_PARM_DESC(report_undeciphered, "Report undeciphered multi-touch state field using a MSC_RAW event");

#define TRACKPAD_REPORT_ID 0x28
#define MOUSE_REPORT_ID    0x29
#define DOUBLE_REPORT_ID   0xf7
/* These definitions are not precise, but they're close enough.  (Bits
 * 0x03 seem to indicate the aspect ratio of the touch, bits 0x70 seem
 * to be some kind of bit mask -- 0x20 may be a near-field reading,
 * and 0x40 is actual contact, and 0x10 may be a start/stop or change
 * indication.)
 */
#define TOUCH_STATE_MASK  0xf0
#define TOUCH_STATE_NONE  0x00
#define TOUCH_STATE_START 0x30
#define TOUCH_STATE_DRAG  0x40

#define SCROLL_ACCEL_DEFAULT 7

/* Single touch emulation should only begin when no touches are currently down.
 * This is true when single_touch_id is equal to NO_TOUCHES. If multiple touches
 * are down and the touch providing for single touch emulation is lifted,
 * single_touch_id is equal to SINGLE_TOUCH_UP. While single touch emulation is
 * occuring, single_touch_id corresponds with the tracking id of the touch used.
 */
#define NO_TOUCHES -1
#define SINGLE_TOUCH_UP -2

/**
 * struct magicmouse_sc - Tracks Magic Mouse-specific data.
 * @input: Input device through which we report events.
 * @quirks: Currently unused.
 * @ntouches: Number of touches in most recent touch report.
 * @scroll_accel: Number of consecutive scroll motions.
 * @scroll_jiffies: Time of last scroll motion.
 * @touches: Most recent data for a touch, indexed by tracking ID.
 * @tracking_ids: Mapping of current touch input data to @touches.
 */
struct magicmouse_sc {
        struct input_dev *input;
        unsigned long quirks;

        int ntouches;
        int scroll_accel;
        unsigned long scroll_jiffies;

        struct {
                short x;
                short y;
                short scroll_x;
                short scroll_y;
                u8 size;
        } touches[16];
        int tracking_ids[16];
        int single_touch_id;
};

static int magicmouse_firm_touch(struct magicmouse_sc *msc)
{
        int touch = -1;
        int ii;

        /* If there is only one "firm" touch, set touch to its
         * tracking ID.
         */
        for (ii = 0; ii < msc->ntouches; ii++) {
                int idx = msc->tracking_ids[ii];
                if (msc->touches[idx].size < 8) {
                        /* Ignore this touch. */
                } else if (touch >= 0) {
                        touch = -1;
                        break;
                } else {
                        touch = idx;
                }
        }

        return touch;
}

static void magicmouse_emit_buttons(struct magicmouse_sc *msc, int state)
{
        int last_state = test_bit(BTN_LEFT, msc->input->key) << 0 |
                test_bit(BTN_RIGHT, msc->input->key) << 1 |
                test_bit(BTN_MIDDLE, msc->input->key) << 2;

        if (emulate_3button) {
                int id;

                /* If some button was pressed before, keep it held
                 * down.  Otherwise, if there's exactly one firm
                 * touch, use that to override the mouse's guess.
                 */
                if (state == 0) {
                        /* The button was released. */
                } else if (last_state != 0) {
                        state = last_state;
                } else if ((id = magicmouse_firm_touch(msc)) >= 0) {
                        int x = msc->touches[id].x;
                        if (x < middle_button_start)
                                state = 1;
                        else if (x > middle_button_stop)
                                state = 2;
                        else
                                state = 4;
                } /* else: we keep the mouse's guess */

                input_report_key(msc->input, BTN_MIDDLE, state & 4);
        }

        input_report_key(msc->input, BTN_LEFT, state & 1);
        input_report_key(msc->input, BTN_RIGHT, state & 2);

        if (state != last_state)
                msc->scroll_accel = SCROLL_ACCEL_DEFAULT;
}

static void magicmouse_emit_touch(struct magicmouse_sc *msc, int raw_id, u8 *tdata)
{
        struct input_dev *input = msc->input;
        int id, x, y, size, orientation, touch_major, touch_minor, state, down;

        if (input->id.product == USB_DEVICE_ID_APPLE_MAGICMOUSE) {
                id = (tdata[6] << 2 | tdata[5] >> 6) & 0xf;
                x = (tdata[1] << 28 | tdata[0] << 20) >> 20;
                y = -((tdata[2] << 24 | tdata[1] << 16) >> 20);
                size = tdata[5] & 0x3f;
                orientation = (tdata[6] >> 2) - 32;
                touch_major = tdata[3];
                touch_minor = tdata[4];
                state = tdata[7] & TOUCH_STATE_MASK;
                down = state != TOUCH_STATE_NONE;
        } else { /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
                id = (tdata[7] << 2 | tdata[6] >> 6) & 0xf;
                x = (tdata[1] << 27 | tdata[0] << 19) >> 19;
                y = -((tdata[3] << 30 | tdata[2] << 22 | tdata[1] << 14) >> 19);
                size = tdata[6] & 0x3f;
                orientation = (tdata[7] >> 2) - 32;
                touch_major = tdata[4];
                touch_minor = tdata[5];
                state = tdata[8] & TOUCH_STATE_MASK;
                down = state != TOUCH_STATE_NONE;
        }

        /* Store tracking ID and other fields. */
        msc->tracking_ids[raw_id] = id;
        msc->touches[id].x = x;
        msc->touches[id].y = y;
        msc->touches[id].size = size;

        /* If requested, emulate a scroll wheel by detecting small
         * vertical touch motions.
         */
        if (emulate_scroll_wheel) {
                unsigned long now = jiffies;
                int step_x = msc->touches[id].scroll_x - x;
                int step_y = msc->touches[id].scroll_y - y;

                /* Calculate and apply the scroll motion. */
                switch (state) {
                case TOUCH_STATE_START:
                        msc->touches[id].scroll_x = x;
                        msc->touches[id].scroll_y = y;

                        /* Reset acceleration after half a second. */
                        if (scroll_acceleration && time_before(now,
                                                msc->scroll_jiffies + HZ / 2))
                                msc->scroll_accel = max_t(int,
                                                msc->scroll_accel - 1, 1);
                        else
                                msc->scroll_accel = SCROLL_ACCEL_DEFAULT;

                        break;
                case TOUCH_STATE_DRAG:
                        step_x /= (64 - (int)scroll_speed) * msc->scroll_accel;
                        if (step_x != 0) {
                                msc->touches[id].scroll_x -= step_x *
                                        (64 - scroll_speed) * msc->scroll_accel;
                                msc->scroll_jiffies = now;
                                input_report_rel(input, REL_HWHEEL, -step_x);
                        }

                        step_y /= (64 - (int)scroll_speed) * msc->scroll_accel;
                        if (step_y != 0) {
                                msc->touches[id].scroll_y -= step_y *
                                        (64 - scroll_speed) * msc->scroll_accel;
                                msc->scroll_jiffies = now;
                                input_report_rel(input, REL_WHEEL, step_y);
                        }
                        break;
                }
        }

        if (down) {
                msc->ntouches++;
                if (msc->single_touch_id == NO_TOUCHES)
                        msc->single_touch_id = id;
        } else if (msc->single_touch_id == id)
                msc->single_touch_id = SINGLE_TOUCH_UP;

        /* Generate the input events for this touch. */
        if (report_touches && down) {
                input_report_abs(input, ABS_MT_TRACKING_ID, id);
                input_report_abs(input, ABS_MT_TOUCH_MAJOR, touch_major << 2);
                input_report_abs(input, ABS_MT_TOUCH_MINOR, touch_minor << 2);
                input_report_abs(input, ABS_MT_ORIENTATION, orientation);
                input_report_abs(input, ABS_MT_POSITION_X, x);
                input_report_abs(input, ABS_MT_POSITION_Y, y);

                if (report_undeciphered) {
                        if (input->id.product == USB_DEVICE_ID_APPLE_MAGICMOUSE)
                                input_event(input, EV_MSC, MSC_RAW, tdata[7]);
                        else /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
                                input_event(input, EV_MSC, MSC_RAW, tdata[8]);
                }

                input_mt_sync(input);
        }
}

static int magicmouse_raw_event(struct hid_device *hdev,
                struct hid_report *report, u8 *data, int size)
{
        struct magicmouse_sc *msc = hid_get_drvdata(hdev);
        struct input_dev *input = msc->input;
        int x = 0, y = 0, ii, clicks = 0, npoints;

        switch (data[0]) {
        case TRACKPAD_REPORT_ID:
                /* Expect four bytes of prefix, and N*9 bytes of touch data. */
                if (size < 4 || ((size - 4) % 9) != 0)
                        return 0;
                npoints = (size - 4) / 9;
                msc->ntouches = 0;
                for (ii = 0; ii < npoints; ii++)
                        magicmouse_emit_touch(msc, ii, data + ii * 9 + 4);

                /* We don't need an MT sync here because trackpad emits a
                 * BTN_TOUCH event in a new frame when all touches are released.
                 */
                if (msc->ntouches == 0)
                        msc->single_touch_id = NO_TOUCHES;

                clicks = data[1];

                /* The following bits provide a device specific timestamp. They
                 * are unused here.
                 *
                 * ts = data[1] >> 6 | data[2] << 2 | data[3] << 10;
                 */
                break;
        case MOUSE_REPORT_ID:
                /* Expect six bytes of prefix, and N*8 bytes of touch data. */
                if (size < 6 || ((size - 6) % 8) != 0)
                        return 0;
                npoints = (size - 6) / 8;
                msc->ntouches = 0;
                for (ii = 0; ii < npoints; ii++)
                        magicmouse_emit_touch(msc, ii, data + ii * 8 + 6);

                if (report_touches && msc->ntouches == 0)
                        input_mt_sync(input);

                /* When emulating three-button mode, it is important
                 * to have the current touch information before
                 * generating a click event.
                 */
                x = (int)(((data[3] & 0x0c) << 28) | (data[1] << 22)) >> 22;
                y = (int)(((data[3] & 0x30) << 26) | (data[2] << 22)) >> 22;
                clicks = data[3];

                /* The following bits provide a device specific timestamp. They
                 * are unused here.
                 *
                 * ts = data[3] >> 6 | data[4] << 2 | data[5] << 10;
                 */
                break;
        case DOUBLE_REPORT_ID:
                /* Sometimes the trackpad sends two touch reports in one
                 * packet.
                 */
                magicmouse_raw_event(hdev, report, data + 2, data[1]);
                magicmouse_raw_event(hdev, report, data + 2 + data[1],
                        size - 2 - data[1]);
                break;
        default:
                return 0;
        }

        if (input->id.product == USB_DEVICE_ID_APPLE_MAGICMOUSE) {
                magicmouse_emit_buttons(msc, clicks & 3);
                input_report_rel(input, REL_X, x);
                input_report_rel(input, REL_Y, y);
        } else { /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
                input_report_key(input, BTN_MOUSE, clicks & 1);
                input_report_key(input, BTN_TOUCH, msc->ntouches > 0);
                input_report_key(input, BTN_TOOL_FINGER, msc->ntouches == 1);
                input_report_key(input, BTN_TOOL_DOUBLETAP, msc->ntouches == 2);
                input_report_key(input, BTN_TOOL_TRIPLETAP, msc->ntouches == 3);
                input_report_key(input, BTN_TOOL_QUADTAP, msc->ntouches == 4);
                if (msc->single_touch_id >= 0) {
                        input_report_abs(input, ABS_X,
                                msc->touches[msc->single_touch_id].x);
                        input_report_abs(input, ABS_Y,
                                msc->touches[msc->single_touch_id].y);
                }
        }

        input_sync(input);
        return 1;
}

static void magicmouse_setup_input(struct input_dev *input, struct hid_device *hdev)
{
        __set_bit(EV_KEY, input->evbit);

        if (input->id.product == USB_DEVICE_ID_APPLE_MAGICMOUSE) {
                __set_bit(BTN_LEFT, input->keybit);
                __set_bit(BTN_RIGHT, input->keybit);
                if (emulate_3button)
                        __set_bit(BTN_MIDDLE, input->keybit);

                __set_bit(EV_REL, input->evbit);
                __set_bit(REL_X, input->relbit);
                __set_bit(REL_Y, input->relbit);
                if (emulate_scroll_wheel) {
                        __set_bit(REL_WHEEL, input->relbit);
                        __set_bit(REL_HWHEEL, input->relbit);
                }
        } else { /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
                __set_bit(BTN_MOUSE, input->keybit);
                __set_bit(BTN_TOOL_FINGER, input->keybit);
                __set_bit(BTN_TOOL_DOUBLETAP, input->keybit);
                __set_bit(BTN_TOOL_TRIPLETAP, input->keybit);
                __set_bit(BTN_TOOL_QUADTAP, input->keybit);
                __set_bit(BTN_TOUCH, input->keybit);
        }

        if (report_touches) {
                __set_bit(EV_ABS, input->evbit);

                input_set_abs_params(input, ABS_MT_TRACKING_ID, 0, 15, 0, 0);
                input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 255, 4, 0);
                input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, 255, 4, 0);
                input_set_abs_params(input, ABS_MT_ORIENTATION, -32, 31, 1, 0);

                /* Note: Touch Y position from the device is inverted relative
                 * to how pointer motion is reported (and relative to how USB
                 * HID recommends the coordinates work).  This driver keeps
                 * the origin at the same position, and just uses the additive
                 * inverse of the reported Y.
                 */
                if (input->id.product == USB_DEVICE_ID_APPLE_MAGICMOUSE) {
                        input_set_abs_params(input, ABS_MT_POSITION_X, -1100,
                                1358, 4, 0);
                        input_set_abs_params(input, ABS_MT_POSITION_Y, -1589,
                                2047, 4, 0);
                } else { /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
                        input_set_abs_params(input, ABS_X, -2909, 3167, 4, 0);
                        input_set_abs_params(input, ABS_Y, -2456, 2565, 4, 0);
                        input_set_abs_params(input, ABS_MT_POSITION_X, -2909,
                                3167, 4, 0);
                        input_set_abs_params(input, ABS_MT_POSITION_Y, -2456,
                                2565, 4, 0);
                }
        }

        if (report_undeciphered) {
                __set_bit(EV_MSC, input->evbit);
                __set_bit(MSC_RAW, input->mscbit);
        }
}

static int magicmouse_input_mapping(struct hid_device *hdev,
                struct hid_input *hi, struct hid_field *field,
                struct hid_usage *usage, unsigned long **bit, int *max)
{
        struct magicmouse_sc *msc = hid_get_drvdata(hdev);

        if (!msc->input)
                msc->input = hi->input;

        /* Magic Trackpad does not give relative data after switching to MT */
        if (hi->input->id.product == USB_DEVICE_ID_APPLE_MAGICTRACKPAD &&
            field->flags & HID_MAIN_ITEM_RELATIVE)
                return -1;

        return 0;
}

static int magicmouse_probe(struct hid_device *hdev,
        const struct hid_device_id *id)
{
        __u8 feature[] = { 0xd7, 0x01 };
        struct magicmouse_sc *msc;
        struct hid_report *report;
        int ret;

        msc = kzalloc(sizeof(*msc), GFP_KERNEL);
        if (msc == NULL) {
                hid_err(hdev, "can't alloc magicmouse descriptor\n");
                return -ENOMEM;
        }

        msc->scroll_accel = SCROLL_ACCEL_DEFAULT;

        msc->quirks = id->driver_data;
        hid_set_drvdata(hdev, msc);

        msc->single_touch_id = NO_TOUCHES;

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

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

        /* We do this after hid-input is done parsing reports so that
         * hid-input uses the most natural button and axis IDs.
         */
        if (msc->input)
                magicmouse_setup_input(msc->input, hdev);

        if (id->product == USB_DEVICE_ID_APPLE_MAGICMOUSE)
                report = hid_register_report(hdev, HID_INPUT_REPORT,
                        MOUSE_REPORT_ID);
        else { /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
                report = hid_register_report(hdev, HID_INPUT_REPORT,
                        TRACKPAD_REPORT_ID);
                report = hid_register_report(hdev, HID_INPUT_REPORT,
                        DOUBLE_REPORT_ID);
        }

        if (!report) {
                hid_err(hdev, "unable to register touch report\n");
                ret = -ENOMEM;
                goto err_stop_hw;
        }
        report->size = 6;

        ret = hdev->hid_output_raw_report(hdev, feature, sizeof(feature),
                        HID_FEATURE_REPORT);
        if (ret != sizeof(feature)) {
                hid_err(hdev, "unable to request touch data (%d)\n", ret);
                goto err_stop_hw;
        }

        return 0;
err_stop_hw:
        hid_hw_stop(hdev);
err_free:
        kfree(msc);
        return ret;
}

static void magicmouse_remove(struct hid_device *hdev)
{
        struct magicmouse_sc *msc = hid_get_drvdata(hdev);

        hid_hw_stop(hdev);
        kfree(msc);
}

static const struct hid_device_id magic_mice[] = {
        { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_APPLE,
                USB_DEVICE_ID_APPLE_MAGICMOUSE), .driver_data = 0 },
        { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_APPLE,
                USB_DEVICE_ID_APPLE_MAGICTRACKPAD), .driver_data = 0 },
        { }
};
MODULE_DEVICE_TABLE(hid, magic_mice);

static struct hid_driver magicmouse_driver = {
        .name = "magicmouse",
        .id_table = magic_mice,
        .probe = magicmouse_probe,
        .remove = magicmouse_remove,
        .raw_event = magicmouse_raw_event,
        .input_mapping = magicmouse_input_mapping,
};

static int __init magicmouse_init(void)
{
        int ret;

        ret = hid_register_driver(&magicmouse_driver);
        if (ret)
                pr_err("can't register magicmouse driver\n");

        return ret;
}

static void __exit magicmouse_exit(void)
{
        hid_unregister_driver(&magicmouse_driver);
}

module_init(magicmouse_init);
module_exit(magicmouse_exit);
MODULE_LICENSE("GPL");