/*
   *   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/input/mt.h>

  #include <linux/module.h>

  #include <linux/slab.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 || kstrtoul(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_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

  /* Touch surface information. Dimension is in hundredths of a mm, min and max
   * are in units. */
  #define MOUSE_DIMENSION_X (float)9056
  #define MOUSE_MIN_X -1100
  #define MOUSE_MAX_X 1258
  #define MOUSE_RES_X ((MOUSE_MAX_X - MOUSE_MIN_X) / (MOUSE_DIMENSION_X / 100))
  #define MOUSE_DIMENSION_Y (float)5152
  #define MOUSE_MIN_Y -1589
  #define MOUSE_MAX_Y 2047
  #define MOUSE_RES_Y ((MOUSE_MAX_Y - MOUSE_MIN_Y) / (MOUSE_DIMENSION_Y / 100))
  
  #define TRACKPAD_DIMENSION_X (float)13000
  #define TRACKPAD_MIN_X -2909
  #define TRACKPAD_MAX_X 3167
  #define TRACKPAD_RES_X \
  	((TRACKPAD_MAX_X - TRACKPAD_MIN_X) / (TRACKPAD_DIMENSION_X / 100))
  #define TRACKPAD_DIMENSION_Y (float)11000
  #define TRACKPAD_MIN_Y -2456
  #define TRACKPAD_MAX_Y 2565
  #define TRACKPAD_RES_Y \
  	((TRACKPAD_MAX_Y - TRACKPAD_MIN_Y) / (TRACKPAD_DIMENSION_Y / 100))

  /**
   * 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];
  };
  
  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++;

  
  	input_mt_slot(input, id);
  	input_mt_report_slot_state(input, MT_TOOL_FINGER, down);

  	/* Generate the input events for this touch. */

  	if (down) {

  		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]);
  		}

  	}
  }
  
  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;

  		if (npoints > 15) {
  			hid_warn(hdev, "invalid size value (%d) for TRACKPAD_REPORT_ID
  ",
  					size);
  			return 0;
  		}

  		msc->ntouches = 0;
  		for (ii = 0; ii < npoints; ii++)
  			magicmouse_emit_touch(msc, ii, data + ii * 9 + 4);

  		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;

  		if (npoints > 15) {
  			hid_warn(hdev, "invalid size value (%d) for MOUSE_REPORT_ID
  ",
  					size);
  			return 0;
  		}

  		msc->ntouches = 0;
  		for (ii = 0; ii < npoints; ii++)

  			magicmouse_emit_touch(msc, ii, data + ii * 8 + 6);

  		/* 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_mt_report_pointer_emulation(input, true);

  	}

  	input_sync(input);
  	return 1;
  }

  static int magicmouse_setup_input(struct input_dev *input, struct hid_device *hdev)

  {

  	int error;

  	__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 */

  		/* input->keybit is initialized with incorrect button info
  		 * for Magic Trackpad. There really is only one physical
  		 * button (BTN_LEFT == BTN_MOUSE). Make sure we don't
  		 * advertise buttons that don't exist...
  		 */
  		__clear_bit(BTN_RIGHT, input->keybit);
  		__clear_bit(BTN_MIDDLE, input->keybit);

  		__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_TOOL_QUINTTAP, input->keybit);
  		__set_bit(BTN_TOUCH, input->keybit);
  		__set_bit(INPUT_PROP_POINTER, input->propbit);

  		__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);

  	}

  	__set_bit(EV_ABS, input->evbit);

  	error = input_mt_init_slots(input, 16, 0);

  	if (error)
  		return error;

  	input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 255 << 2,
  			     4, 0);
  	input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, 255 << 2,
  			     4, 0);
  	input_set_abs_params(input, ABS_MT_ORIENTATION, -31, 32, 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,
  				     MOUSE_MIN_X, MOUSE_MAX_X, 4, 0);
  		input_set_abs_params(input, ABS_MT_POSITION_Y,
  				     MOUSE_MIN_Y, MOUSE_MAX_Y, 4, 0);
  
  		input_abs_set_res(input, ABS_MT_POSITION_X,
  				  MOUSE_RES_X);
  		input_abs_set_res(input, ABS_MT_POSITION_Y,
  				  MOUSE_RES_Y);
  	} else { /* USB_DEVICE_ID_APPLE_MAGICTRACKPAD */
  		input_set_abs_params(input, ABS_X, TRACKPAD_MIN_X,
  				     TRACKPAD_MAX_X, 4, 0);
  		input_set_abs_params(input, ABS_Y, TRACKPAD_MIN_Y,
  				     TRACKPAD_MAX_Y, 4, 0);
  		input_set_abs_params(input, ABS_MT_POSITION_X,
  				     TRACKPAD_MIN_X, TRACKPAD_MAX_X, 4, 0);
  		input_set_abs_params(input, ABS_MT_POSITION_Y,
  				     TRACKPAD_MIN_Y, TRACKPAD_MAX_Y, 4, 0);
  
  		input_abs_set_res(input, ABS_X, TRACKPAD_RES_X);
  		input_abs_set_res(input, ABS_Y, TRACKPAD_RES_Y);
  		input_abs_set_res(input, ABS_MT_POSITION_X,
  				  TRACKPAD_RES_X);
  		input_abs_set_res(input, ABS_MT_POSITION_Y,
  				  TRACKPAD_RES_Y);

  	}

  	input_set_events_per_packet(input, 60);

  	if (report_undeciphered) {

  		__set_bit(EV_MSC, input->evbit);
  		__set_bit(MSC_RAW, input->mscbit);

  	}

  
  	return 0;

  }

  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_input_configured(struct hid_device *hdev,

  		struct hid_input *hi)
  
  {
  	struct magicmouse_sc *msc = hid_get_drvdata(hdev);

  	int ret;

  	ret = magicmouse_setup_input(msc->input, hdev);

  	if (ret) {
  		hid_err(hdev, "magicmouse setup input failed (%d)
  ", ret);
  		/* clean msc->input to notify probe() of the failure */
  		msc->input = NULL;

  		return ret;

  	}

  
  	return 0;

  }

  static int magicmouse_probe(struct hid_device *hdev,
  	const struct hid_device_id *id)
  {

  	const u8 feature[] = { 0xd7, 0x01 };
  	u8 *buf;

  	struct magicmouse_sc *msc;
  	struct hid_report *report;
  	int ret;

  	msc = devm_kzalloc(&hdev->dev, sizeof(*msc), GFP_KERNEL);

  	if (msc == NULL) {

  		hid_err(hdev, "can't alloc magicmouse descriptor
  ");

  		return -ENOMEM;
  	}

  	msc->scroll_accel = SCROLL_ACCEL_DEFAULT;

  	msc->quirks = id->driver_data;
  	hid_set_drvdata(hdev, msc);
  
  	ret = hid_parse(hdev);
  	if (ret) {

  		hid_err(hdev, "magicmouse hid parse failed
  ");

  		return ret;

  	}

  	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);

  	if (ret) {

  		hid_err(hdev, "magicmouse hw start failed
  ");

  		return ret;

  	}

  	if (!msc->input) {
  		hid_err(hdev, "magicmouse input not registered
  ");
  		ret = -ENOMEM;
  		goto err_stop_hw;

  	}

  	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
  ");

  		ret = -ENOMEM;

  		goto err_stop_hw;

  	}
  	report->size = 6;

  	buf = kmemdup(feature, sizeof(feature), GFP_KERNEL);
  	if (!buf) {
  		ret = -ENOMEM;
  		goto err_stop_hw;
  	}

  	/*
  	 * Some devices repond with 'invalid report id' when feature
  	 * report switching it into multitouch mode is sent to it.
  	 *
  	 * This results in -EIO from the _raw low-level transport callback,
  	 * but there seems to be no other way of switching the mode.
  	 * Thus the super-ugly hacky success check below.
  	 */

  	ret = hid_hw_raw_request(hdev, buf[0], buf, sizeof(feature),

  				HID_FEATURE_REPORT, HID_REQ_SET_REPORT);

  	kfree(buf);

  	if (ret != -EIO && ret != sizeof(feature)) {

  		hid_err(hdev, "unable to request touch data (%d)
  ", ret);

  		goto err_stop_hw;

  	}

  	return 0;

  err_stop_hw:
  	hid_hw_stop(hdev);

  	return ret;
  }

  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,

  	.raw_event = magicmouse_raw_event,

  	.input_mapping = magicmouse_input_mapping,

  	.input_configured = magicmouse_input_configured,

  };

  module_hid_driver(magicmouse_driver);

  MODULE_LICENSE("GPL");