HID: add a device driver for the Apple Magic Mouse.

The Magic Mouse requires that a driver send an unlock Report(Feature) command,
similar to the Wacom wireless tablet and Sixaxis controller quirks.  This turns
on an Input Report that isn't published in the input Report descriptor that
contains touch data (and usually overrides the normal motion and click Report).

Because the mouse has only one switch and no scroll wheel, the driver
(under control of parameters) emulates a middle button and scroll wheel.
User space could also ignore and/or re-synthesize those events based on
the reported events.

Some user-space tools to talk to the mouse directly (that is, when it is not
associated with the host's HIDP stack) are at
http://github.com/entrope/linux-magicmouse

Signed-off-by: Michael Poole <mdpoole@troilus.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 469 insertions, 0 deletions

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
new file mode 100644
index 0000000..f94b3e4
--- /dev/null
+++ b/drivers/hid/hid-magicmouse.c
@@ -0,0 +1,469 @@
+/*
+ *   Apple "Magic" Wireless Mouse driver
+ *
+ *   Copyright (c) 2010 Michael Poole <mdpoole@troilus.org>
+ */
+
+/*
+ * 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.
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+
+static bool emulate_3button = 1;
+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 = 1;
+module_param(emulate_scroll_wheel, bool, 0644);
+MODULE_PARM_DESC(emulate_scroll_wheel, "Emulate a scroll wheel");
+
+static bool report_touches = 1;
+module_param(report_touches, bool, 0644);
+MODULE_PARM_DESC(report_touches, "Emit touch records (otherwise, only use them for emulation)");
+
+static bool report_undeciphered = 0;
+module_param(report_undeciphered, bool, 0644);
+MODULE_PARM_DESC(report_undeciphered, "Report undeciphered multi-touch state field using a MSC_RAW event");
+
+#define TOUCH_REPORT_ID   0x29
+/* 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
+
+/**
+ * struct magicmouse_sc - Tracks Magic Mouse-specific data.
+ * @input: Input device through which we report events.
+ * @quirks: Currently unused.
+ * @last_timestamp: Timestamp from most recent (18-bit) touch report
+ *     (units of milliseconds over short windows, but seems to
+ *     increase faster when there are no touches).
+ * @delta_time: 18-bit difference between the two most recent touch
+ *     reports from the mouse.
+ * @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 last_timestamp;
+	int delta_time;
+	int ntouches;
+	int scroll_accel;
+	unsigned long scroll_jiffies;
+
+	struct {
+		short x;
+		short y;
+		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 = 0;
+}
+
+static void magicmouse_emit_touch(struct magicmouse_sc *msc, int raw_id, u8 *tdata)
+{
+	struct input_dev *input = msc->input;
+	__s32 x_y = tdata[0] << 8 | tdata[1] << 16 | tdata[2] << 24;
+	int misc = tdata[5] | tdata[6] << 8;
+	int id = (misc >> 6) & 15;
+	int x = x_y << 12 >> 20;
+	int y = -(x_y >> 20);
+
+	/* 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 = misc & 63;
+
+	/* If requested, emulate a scroll wheel by detecting small
+	 * vertical touch motions along the middle of the mouse.
+	 */
+	if (emulate_scroll_wheel &&
+	    middle_button_start < x && x < middle_button_stop) {
+		static const int accel_profile[] = {
+			256, 228, 192, 160, 128, 96, 64, 32,
+		};
+		unsigned long now = jiffies;
+		int step = msc->touches[id].scroll_y - y;
+
+		/* Reset acceleration after half a second. */
+		if (time_after(now, msc->scroll_jiffies + HZ / 2))
+			msc->scroll_accel = 0;
+
+		/* Calculate and apply the scroll motion. */
+		switch (tdata[7] & TOUCH_STATE_MASK) {
+		case TOUCH_STATE_START:
+			msc->touches[id].scroll_y = y;
+                        msc->scroll_accel = min_t(int, msc->scroll_accel + 1,
+						ARRAY_SIZE(accel_profile) - 1);
+			break;
+		case TOUCH_STATE_DRAG:
+			step = step / accel_profile[msc->scroll_accel];
+			if (step != 0) {
+				msc->touches[id].scroll_y = y;
+				msc->scroll_jiffies = now;
+				input_report_rel(input, REL_WHEEL, step);
+			}
+			break;
+		}
+	}
+
+	/* Generate the input events for this touch. */
+	if (report_touches) {
+                int orientation = (misc >> 10) - 32;
+
+		input_report_abs(input, ABS_MT_TRACKING_ID, id);
+		input_report_abs(input, ABS_MT_TOUCH_MAJOR, tdata[3]);
+		input_report_abs(input, ABS_MT_TOUCH_MINOR, tdata[4]);
+		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) {
+			input_event(input, EV_MSC, MSC_RAW, tdata[7]);
+		}
+
+		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, y, ts, ii, clicks;
+
+	switch (data[0]) {
+	case 0x10:
+		if (size != 6)
+			return 0;
+		x = (__s16)(data[2] | data[3] << 8);
+		y = (__s16)(data[4] | data[5] << 8);
+		clicks = data[1];
+		break;
+	case TOUCH_REPORT_ID:
+		/* Expect six bytes of prefix, and N*8 bytes of touch data. */
+		if (size < 6 || ((size - 6) % 8) != 0)
+			return 0;
+		ts = data[3] >> 6 | data[4] << 2 | data[5] << 10;
+		msc->delta_time = (ts - msc->last_timestamp) & 0x3ffff;
+		msc->last_timestamp = ts;
+		msc->ntouches = (size - 6) / 8;
+		for (ii = 0; ii < msc->ntouches; 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 = (signed char)data[1];
+		y = (signed char)data[2];
+		clicks = data[3];
+		break;
+	case 0x20: /* Theoretically battery status (0-100), but I have
+		    * never seen it -- maybe it is only upon request.
+		    */
+	case 0x60: /* Unknown, maybe laser on/off. */
+	case 0x61: /* Laser reflection status change.
+		    * data[1]: 0 = spotted, 1 = lost
+		    */
+	default:
+		return 0;
+	}
+
+	magicmouse_emit_buttons(msc, clicks & 3);
+	input_report_rel(input, REL_X, x);
+	input_report_rel(input, REL_Y, y);
+	input_sync(input);
+	return 1;
+}
+
+static int magicmouse_input_open(struct input_dev *dev)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+
+	return hid->ll_driver->open(hid);
+}
+
+static void magicmouse_input_close(struct input_dev *dev)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+
+	hid->ll_driver->close(hid);
+}
+
+static void magicmouse_setup_input(struct input_dev *input, struct hid_device *hdev)
+{
+	input_set_drvdata(input, hdev);
+	input->event = hdev->ll_driver->hidinput_input_event;
+	input->open = magicmouse_input_open;
+	input->close = magicmouse_input_close;
+
+	input->name = hdev->name;
+	input->phys = hdev->phys;
+	input->uniq = hdev->uniq;
+	input->id.bustype = hdev->bus;
+	input->id.vendor = hdev->vendor;
+	input->id.product = hdev->product;
+	input->id.version = hdev->version;
+	input->dev.parent = hdev->dev.parent;
+
+	set_bit(EV_KEY, input->evbit);
+	set_bit(BTN_LEFT, input->keybit);
+	set_bit(BTN_RIGHT, input->keybit);
+	if (emulate_3button)
+		set_bit(BTN_MIDDLE, input->keybit);
+	set_bit(BTN_TOOL_FINGER, 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);
+
+	if (report_touches) {
+		set_bit(EV_ABS, input->evbit);
+
+		set_bit(ABS_MT_TRACKING_ID, input->absbit);
+		input->absmin[ABS_MT_TRACKING_ID] = 0;
+		input->absmax[ABS_MT_TRACKING_ID] = 15;
+		input->absfuzz[ABS_MT_TRACKING_ID] = 0;
+
+		set_bit(ABS_MT_TOUCH_MAJOR, input->absbit);
+		input->absmin[ABS_MT_TOUCH_MAJOR] = 0;
+		input->absmax[ABS_MT_TOUCH_MAJOR] = 255;
+		input->absfuzz[ABS_MT_TOUCH_MAJOR] = 4;
+
+		set_bit(ABS_MT_TOUCH_MINOR, input->absbit);
+		input->absmin[ABS_MT_TOUCH_MINOR] = 0;
+		input->absmax[ABS_MT_TOUCH_MINOR] = 255;
+		input->absfuzz[ABS_MT_TOUCH_MINOR] = 4;
+
+		set_bit(ABS_MT_ORIENTATION, input->absbit);
+		input->absmin[ABS_MT_ORIENTATION] = -32;
+		input->absmax[ABS_MT_ORIENTATION] = 31;
+		input->absfuzz[ABS_MT_ORIENTATION] = 1;
+
+		set_bit(ABS_MT_POSITION_X, input->absbit);
+		input->absmin[ABS_MT_POSITION_X] = -1100;
+		input->absmax[ABS_MT_POSITION_X] = 1358;
+		input->absfuzz[ABS_MT_POSITION_X] = 4;
+
+		/* 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.
+		 */
+		set_bit(ABS_MT_POSITION_Y, input->absbit);
+		input->absmin[ABS_MT_POSITION_Y] = -1589;
+		input->absmax[ABS_MT_POSITION_Y] = 2047;
+		input->absfuzz[ABS_MT_POSITION_Y] = 4;
+	}
+
+	if (report_undeciphered) {
+		set_bit(EV_MSC, input->evbit);
+		set_bit(MSC_RAW, input->mscbit);
+	}
+}
+
+static int magicmouse_probe(struct hid_device *hdev,
+	const struct hid_device_id *id)
+{
+	__u8 feature_1[] = { 0xd7, 0x01 };
+	__u8 feature_2[] = { 0xf8, 0x01, 0x32 };
+	struct input_dev *input;
+	struct magicmouse_sc *msc;
+	struct hid_report *report;
+	int ret;
+
+	msc = kzalloc(sizeof(*msc), GFP_KERNEL);
+	if (msc == NULL) {
+		dev_err(&hdev->dev, "can't alloc magicmouse descriptor\n");
+		return -ENOMEM;
+	}
+
+	msc->quirks = id->driver_data;
+	hid_set_drvdata(hdev, msc);
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		dev_err(&hdev->dev, "magicmouse hid parse failed\n");
+		goto err_free;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		dev_err(&hdev->dev, "magicmouse hw start failed\n");
+		goto err_free;
+	}
+
+	report = hid_register_report(hdev, HID_INPUT_REPORT, TOUCH_REPORT_ID);
+	if (!report) {
+		dev_err(&hdev->dev, "unable to register touch report\n");
+		ret = -ENOMEM;
+		goto err_free;
+	}
+	report->size = 6;
+
+	ret = hdev->hid_output_raw_report(hdev, feature_1, sizeof(feature_1),
+			HID_FEATURE_REPORT);
+	if (ret != sizeof(feature_1)) {
+		dev_err(&hdev->dev, "unable to request touch data (1:%d)\n",
+				ret);
+		goto err_free;
+	}
+	ret = hdev->hid_output_raw_report(hdev, feature_2,
+			sizeof(feature_2), HID_FEATURE_REPORT);
+	if (ret != sizeof(feature_2)) {
+		dev_err(&hdev->dev, "unable to request touch data (2:%d)\n",
+				ret);
+		goto err_free;
+	}
+
+	input = input_allocate_device();
+	if (!input) {
+		dev_err(&hdev->dev, "can't alloc input device\n");
+		ret = -ENOMEM;
+		goto err_free;
+	}
+	magicmouse_setup_input(input, hdev);
+
+	ret = input_register_device(input);
+	if (ret) {
+		dev_err(&hdev->dev, "input device registration failed\n");
+		goto err_both;
+	}
+	msc->input = input;
+
+	return 0;
+ err_both:
+	input_free_device(input);
+ err_free:
+	kfree(msc);
+	return ret;
+}
+
+static void magicmouse_remove(struct hid_device *hdev)
+{
+	hid_hw_stop(hdev);
+	kfree(hid_get_drvdata(hdev));
+}
+
+static const struct hid_device_id magic_mice[] = {
+	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGICMOUSE),
+		.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,
+};
+
+static int __init magicmouse_init(void)
+{
+	int ret;
+
+	ret = hid_register_driver(&magicmouse_driver);
+	if (ret)
+		printk(KERN_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");