Input: bcm5974 - add driver for Macbook Air and Pro Penryn touchpads

This driver adds support for the multitouch trackpad on the new
Apple Macbook Air and Macbook Pro Penryn laptops. It replaces the
appletouch driver on those computers, and integrates well with the
synaptics driver of the Xorg system.

[dtor@mail.ru: various cleanups]
Signed-off-by: NHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

drivers/hid/usbhid/hid-quirks.c

@@ -654,12 +654,12 @@ static const struct hid_blacklist {
 	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_ALU_WIRELESS_ANSI, HID_QUIRK_APPLE_NUMLOCK_EMULATION | HID_QUIRK_APPLE_HAS_FN },
 	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_ALU_WIRELESS_ISO, HID_QUIRK_APPLE_NUMLOCK_EMULATION | HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_APPLE_ISO_KEYBOARD },
 	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_ALU_WIRELESS_JIS, HID_QUIRK_APPLE_NUMLOCK_EMULATION | HID_QUIRK_APPLE_HAS_FN },
-	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING_ANSI, HID_QUIRK_APPLE_HAS_FN },
-	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING_ISO, HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_APPLE_ISO_KEYBOARD },
-	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING_JIS, HID_QUIRK_APPLE_HAS_FN },
-	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING2_ANSI, HID_QUIRK_APPLE_HAS_FN },
-	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING2_ISO, HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_APPLE_ISO_KEYBOARD },
-	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING2_JIS, HID_QUIRK_APPLE_HAS_FN },
+	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING_ANSI, HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_IGNORE_MOUSE },
+	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING_ISO, HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_APPLE_ISO_KEYBOARD | HID_QUIRK_IGNORE_MOUSE},
+	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING_JIS, HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_IGNORE_MOUSE},
+	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING2_ANSI, HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_IGNORE_MOUSE},
+	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING2_ISO, HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_APPLE_ISO_KEYBOARD | HID_QUIRK_IGNORE_MOUSE },
+	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_WELLSPRING2_JIS, HID_QUIRK_APPLE_HAS_FN  | HID_QUIRK_IGNORE_MOUSE },
 	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_FOUNTAIN_TP_ONLY, HID_QUIRK_APPLE_NUMLOCK_EMULATION | HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_IGNORE_MOUSE },
 	{ USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_GEYSER1_TP_ONLY, HID_QUIRK_APPLE_NUMLOCK_EMULATION | HID_QUIRK_APPLE_HAS_FN | HID_QUIRK_IGNORE_MOUSE },
 

drivers/input/mouse/Kconfig

@@ -130,6 +130,29 @@ config MOUSE_APPLETOUCH
 	  To compile this driver as a module, choose M here: the
 	  module will be called appletouch.
 
+config MOUSE_BCM5974
+	tristate "Apple USB BCM5974 Multitouch trackpad support"
+	depends on USB_ARCH_HAS_HCD
+	select USB
+	help
+	  Say Y here if you have an Apple USB BCM5974 Multitouch
+	  trackpad.
+
+	  The BCM5974 is the multitouch trackpad found in the Macbook
+	  Air (JAN2008) and Macbook Pro Penryn (FEB2008) laptops.
+
+	  It is also found in the IPhone (2007) and Ipod Touch (2008).
+
+	  This driver provides multitouch functionality together with
+	  the synaptics X11 driver.
+
+	  The interface is currently identical to the appletouch interface,
+	  for further information, see
+	  <file:Documentation/input/appletouch.txt>.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called bcm5974.
+
 config MOUSE_INPORT
 	tristate "InPort/MS/ATIXL busmouse"
 	depends on ISA

drivers/input/mouse/Makefile

@@ -6,6 +6,7 @@
 
 obj-$(CONFIG_MOUSE_AMIGA)	+= amimouse.o
 obj-$(CONFIG_MOUSE_APPLETOUCH)	+= appletouch.o
+obj-$(CONFIG_MOUSE_BCM5974)	+= bcm5974.o
 obj-$(CONFIG_MOUSE_ATARI)	+= atarimouse.o
 obj-$(CONFIG_MOUSE_RISCPC)	+= rpcmouse.o
 obj-$(CONFIG_MOUSE_INPORT)	+= inport.o

drivers/input/mouse/bcm5974.c

+/*
+ * Apple USB BCM5974 (Macbook Air and Penryn Macbook Pro) multitouch driver
+ *
+ * Copyright (C) 2008	   Henrik Rydberg (rydberg@euromail.se)
+ *
+ * The USB initialization and package decoding was made by
+ * Scott Shawcroft as part of the touchd user-space driver project:
+ * Copyright (C) 2008	   Scott Shawcroft (scott.shawcroft@gmail.com)
+ *
+ * The BCM5974 driver is based on the appletouch driver:
+ * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
+ * Copyright (C) 2005      Johannes Berg (johannes@sipsolutions.net)
+ * Copyright (C) 2005	   Stelian Pop (stelian@popies.net)
+ * Copyright (C) 2005	   Frank Arnold (frank@scirocco-5v-turbo.de)
+ * Copyright (C) 2005	   Peter Osterlund (petero2@telia.com)
+ * Copyright (C) 2005	   Michael Hanselmann (linux-kernel@hansmi.ch)
+ * Copyright (C) 2006	   Nicolas Boichat (nicolas@boichat.ch)
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/usb/input.h>
+#include <linux/hid.h>
+#include <linux/mutex.h>
+
+#define USB_VENDOR_ID_APPLE		0x05ac
+
+/* MacbookAir, aka wellspring */
+#define USB_DEVICE_ID_APPLE_WELLSPRING_ANSI	0x0223
+#define USB_DEVICE_ID_APPLE_WELLSPRING_ISO	0x0224
+#define USB_DEVICE_ID_APPLE_WELLSPRING_JIS	0x0225
+/* MacbookProPenryn, aka wellspring2 */
+#define USB_DEVICE_ID_APPLE_WELLSPRING2_ANSI	0x0230
+#define USB_DEVICE_ID_APPLE_WELLSPRING2_ISO	0x0231
+#define USB_DEVICE_ID_APPLE_WELLSPRING2_JIS	0x0232
+
+#define BCM5974_DEVICE(prod) {					\
+	.match_flags = (USB_DEVICE_ID_MATCH_DEVICE |		\
+			USB_DEVICE_ID_MATCH_INT_CLASS |		\
+			USB_DEVICE_ID_MATCH_INT_PROTOCOL),	\
+	.idVendor = USB_VENDOR_ID_APPLE,			\
+	.idProduct = (prod),					\
+	.bInterfaceClass = USB_INTERFACE_CLASS_HID,		\
+	.bInterfaceProtocol = USB_INTERFACE_PROTOCOL_MOUSE	\
+}
+
+/* table of devices that work with this driver */
+static const struct usb_device_id bcm5974_table [] = {
+	/* MacbookAir1.1 */
+	BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING_ANSI),
+	BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING_ISO),
+	BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING_JIS),
+	/* MacbookProPenryn */
+	BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING2_ANSI),
+	BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING2_ISO),
+	BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING2_JIS),
+	/* Terminating entry */
+	{}
+};
+MODULE_DEVICE_TABLE(usb, bcm5974_table);
+
+MODULE_AUTHOR("Henrik Rydberg");
+MODULE_DESCRIPTION("Apple USB BCM5974 multitouch driver");
+MODULE_LICENSE("GPL");
+
+#define dprintk(level, format, a...)\
+	{ if (debug >= level) printk(KERN_DEBUG format, ##a); }
+
+static int debug = 1;
+module_param(debug, int, 0644);
+MODULE_PARM_DESC(debug, "Activate debugging output");
+
+/* button data structure */
+struct bt_data {
+	u8 unknown1;		/* constant */
+	u8 button;		/* left button */
+	u8 rel_x;		/* relative x coordinate */
+	u8 rel_y;		/* relative y coordinate */
+};
+
+/* trackpad header structure */
+struct tp_header {
+	u8 unknown1[16];	/* constants, timers, etc */
+	u8 fingers;		/* number of fingers on trackpad */
+	u8 unknown2[9];		/* constants, timers, etc */
+};
+
+/* trackpad finger structure */
+struct tp_finger {
+	__le16 origin;		/* left/right origin? */
+	__le16 abs_x;		/* absolute x coodinate */
+	__le16 abs_y;		/* absolute y coodinate */
+	__le16 rel_x;		/* relative x coodinate */
+	__le16 rel_y;		/* relative y coodinate */
+	__le16 size_major;	/* finger size, major axis? */
+	__le16 size_minor;	/* finger size, minor axis? */
+	__le16 orientation;	/* 16384 when point, else 15 bit angle */
+	__le16 force_major;	/* trackpad force, major axis? */
+	__le16 force_minor;	/* trackpad force, minor axis? */
+	__le16 unused[3];	/* zeros */
+	__le16 multi;		/* one finger: varies, more fingers: constant */
+};
+
+/* trackpad data structure, empirically at least ten fingers */
+struct tp_data {
+	struct tp_header header;
+	struct tp_finger finger[16];
+};
+
+/* device-specific parameters */
+struct bcm5974_param {
+	int dim;		/* logical dimension */
+	int fuzz;		/* logical noise value */
+	int devmin;		/* device minimum reading */
+	int devmax;		/* device maximum reading */
+};
+
+/* device-specific configuration */
+struct bcm5974_config {
+	int ansi, iso, jis;	/* the product id of this device */
+	int bt_ep;		/* the endpoint of the button interface */
+	int bt_datalen;		/* data length of the button interface */
+	int tp_ep;		/* the endpoint of the trackpad interface */
+	int tp_datalen;		/* data length of the trackpad interface */
+	struct bcm5974_param p;	/* finger pressure limits */
+	struct bcm5974_param w;	/* finger width limits */
+	struct bcm5974_param x;	/* horizontal limits */
+	struct bcm5974_param y;	/* vertical limits */
+};
+
+/* logical device structure */
+struct bcm5974 {
+	char phys[64];
+	struct usb_device *udev;	/* usb device */
+	struct input_dev *input;	/* input dev */
+	struct bcm5974_config cfg;	/* device configuration */
+	struct mutex pm_mutex;		/* serialize access to open/suspend */
+	int opened;			/* 1: opened, 0: closed */
+	struct urb *bt_urb;		/* button usb request block */
+	struct bt_data *bt_data;	/* button transferred data */
+	struct urb *tp_urb;		/* trackpad usb request block */
+	struct tp_data *tp_data;	/* trackpad transferred data */
+};
+
+/* logical dimensions */
+#define DIM_PRESSURE	256		/* maximum finger pressure */
+#define DIM_WIDTH	16		/* maximum finger width */
+#define DIM_X		1280		/* maximum trackpad x value */
+#define DIM_Y		800		/* maximum trackpad y value */
+
+/* logical signal quality */
+#define SN_PRESSURE	45		/* pressure signal-to-noise ratio */
+#define SN_WIDTH	100		/* width signal-to-noise ratio */
+#define SN_COORD	250		/* coordinate signal-to-noise ratio */
+
+/* device constants */
+static const struct bcm5974_config bcm5974_config_table[] = {
+	{
+		USB_DEVICE_ID_APPLE_WELLSPRING_ANSI,
+		USB_DEVICE_ID_APPLE_WELLSPRING_ISO,
+		USB_DEVICE_ID_APPLE_WELLSPRING_JIS,
+		0x84, sizeof(struct bt_data),
+		0x81, sizeof(struct tp_data),
+		{ DIM_PRESSURE, DIM_PRESSURE / SN_PRESSURE, 0, 256 },
+		{ DIM_WIDTH, DIM_WIDTH / SN_WIDTH, 0, 2048 },
+		{ DIM_X, DIM_X / SN_COORD, -4824, 5342 },
+		{ DIM_Y, DIM_Y / SN_COORD, -172, 5820 }
+	},
+	{
+		USB_DEVICE_ID_APPLE_WELLSPRING2_ANSI,
+		USB_DEVICE_ID_APPLE_WELLSPRING2_ISO,
+		USB_DEVICE_ID_APPLE_WELLSPRING2_JIS,
+		0x84, sizeof(struct bt_data),
+		0x81, sizeof(struct tp_data),
+		{ DIM_PRESSURE, DIM_PRESSURE / SN_PRESSURE, 0, 256 },
+		{ DIM_WIDTH, DIM_WIDTH / SN_WIDTH, 0, 2048 },
+		{ DIM_X, DIM_X / SN_COORD, -4824, 4824 },
+		{ DIM_Y, DIM_Y / SN_COORD, -172, 4290 }
+	},
+	{}
+};
+
+/* return the device-specific configuration by device */
+static const struct bcm5974_config *bcm5974_get_config(struct usb_device *udev)
+{
+	u16 id = le16_to_cpu(udev->descriptor.idProduct);
+	const struct bcm5974_config *cfg;
+
+	for (cfg = bcm5974_config_table; cfg->ansi; ++cfg)
+		if (cfg->ansi == id || cfg->iso == id || cfg->jis == id)
+			return cfg;
+
+	return bcm5974_config_table;
+}
+
+/* convert 16-bit little endian to signed integer */
+static inline int raw2int(__le16 x)
+{
+	return (signed short)le16_to_cpu(x);
+}
+
+/* scale device data to logical dimensions (asserts devmin < devmax) */
+static inline int int2scale(const struct bcm5974_param *p, int x)
+{
+	return x * p->dim / (p->devmax - p->devmin);
+}
+
+/* all logical value ranges are [0,dim). */
+static inline int int2bound(const struct bcm5974_param *p, int x)
+{
+	int s = int2scale(p, x);
+
+	return clamp_val(s, 0, p->dim - 1);
+}
+
+/* setup which logical events to report */
+static void setup_events_to_report(struct input_dev *input_dev,
+				   const struct bcm5974_config *cfg)
+{
+	__set_bit(EV_ABS, input_dev->evbit);
+
+	input_set_abs_params(input_dev, ABS_PRESSURE,
+				0, cfg->p.dim, cfg->p.fuzz, 0);
+	input_set_abs_params(input_dev, ABS_TOOL_WIDTH,
+				0, cfg->w.dim, cfg->w.fuzz, 0);
+	input_set_abs_params(input_dev, ABS_X,
+				0, cfg->x.dim, cfg->x.fuzz, 0);
+	input_set_abs_params(input_dev, ABS_Y,
+				0, cfg->y.dim, cfg->y.fuzz, 0);
+
+	__set_bit(EV_KEY, input_dev->evbit);
+	__set_bit(BTN_TOOL_FINGER, input_dev->keybit);
+	__set_bit(BTN_TOOL_DOUBLETAP, input_dev->keybit);
+	__set_bit(BTN_TOOL_TRIPLETAP, input_dev->keybit);
+	__set_bit(BTN_LEFT, input_dev->keybit);
+}
+
+/* report button data as logical button state */
+static int report_bt_state(struct bcm5974 *dev, int size)
+{
+	if (size != sizeof(struct bt_data))
+		return -EIO;
+
+	input_report_key(dev->input, BTN_LEFT, dev->bt_data->button);
+	input_sync(dev->input);
+
+	return 0;
+}
+
+/* report trackpad data as logical trackpad state */
+static int report_tp_state(struct bcm5974 *dev, int size)
+{
+	const struct bcm5974_config *c = &dev->cfg;
+	const struct tp_finger *f = dev->tp_data->finger;
+	struct input_dev *input = dev->input;
+	const int fingers = (size - 26) / 28;
+	int p = 0, w, x, y, n = 0;
+
+	if (size < 26 || (size - 26) % 28 != 0)
+		return -EIO;
+
+	if (fingers) {
+		p = raw2int(f->force_major);
+		w = raw2int(f->size_major);
+		x = raw2int(f->abs_x);
+		y = raw2int(f->abs_y);
+		n = p > 0 ? fingers : 0;
+
+		dprintk(9,
+			"bcm5974: p: %+05d w: %+05d x: %+05d y: %+05d n: %d\n",
+			p, w, x, y, n);
+
+		input_report_abs(input, ABS_TOOL_WIDTH, int2bound(&c->w, w));
+		input_report_abs(input, ABS_X, int2bound(&c->x, x - c->x.devmin));
+		input_report_abs(input, ABS_Y, int2bound(&c->y, c->y.devmax - y));
+	}
+
+	input_report_abs(input, ABS_PRESSURE, int2bound(&c->p, p));
+
+	input_report_key(input, BTN_TOOL_FINGER, n == 1);
+	input_report_key(input, BTN_TOOL_DOUBLETAP, n == 2);
+	input_report_key(input, BTN_TOOL_TRIPLETAP, n > 2);
+
+	input_sync(input);
+
+	return 0;
+}
+
+/* Wellspring initialization constants */
+#define BCM5974_WELLSPRING_MODE_READ_REQUEST_ID		1
+#define BCM5974_WELLSPRING_MODE_WRITE_REQUEST_ID	9
+#define BCM5974_WELLSPRING_MODE_REQUEST_VALUE		0x300
+#define BCM5974_WELLSPRING_MODE_REQUEST_INDEX		0
+#define BCM5974_WELLSPRING_MODE_VENDOR_VALUE		0x01
+
+static int bcm5974_wellspring_mode(struct bcm5974 *dev)
+{
+	char *data = kmalloc(8, GFP_KERNEL);
+	int retval = 0, size;
+
+	if (!data) {
+		err("bcm5974: out of memory");
+		retval = -ENOMEM;
+		goto out;
+	}
+
+	/* read configuration */
+	size = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
+			BCM5974_WELLSPRING_MODE_READ_REQUEST_ID,
+			USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+			BCM5974_WELLSPRING_MODE_REQUEST_VALUE,
+			BCM5974_WELLSPRING_MODE_REQUEST_INDEX, data, 8, 5000);
+
+	if (size != 8) {
+		err("bcm5974: could not read from device");
+		retval = -EIO;
+		goto out;
+	}
+
+	/* apply the mode switch */
+	data[0] = BCM5974_WELLSPRING_MODE_VENDOR_VALUE;
+
+	/* write configuration */
+	size = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
+			BCM5974_WELLSPRING_MODE_WRITE_REQUEST_ID,
+			USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+			BCM5974_WELLSPRING_MODE_REQUEST_VALUE,
+			BCM5974_WELLSPRING_MODE_REQUEST_INDEX, data, 8, 5000);
+
+	if (size != 8) {
+		err("bcm5974: could not write to device");
+		retval = -EIO;
+		goto out;
+	}
+
+	dprintk(2, "bcm5974: switched to wellspring mode.\n");
+
+ out:
+	kfree(data);
+	return retval;
+}
+
+static void bcm5974_irq_button(struct urb *urb)
+{
+	struct bcm5974 *dev = urb->context;
+	int error;
+
+	switch (urb->status) {
+	case 0:
+		break;
+	case -EOVERFLOW:
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		dbg("bcm5974: button urb shutting down: %d", urb->status);
+		return;
+	default:
+		dbg("bcm5974: button urb status: %d", urb->status);
+		goto exit;
+	}
+
+	if (report_bt_state(dev, dev->bt_urb->actual_length))
+		dprintk(1, "bcm5974: bad button package, length: %d\n",
+			dev->bt_urb->actual_length);
+
+exit:
+	error = usb_submit_urb(dev->bt_urb, GFP_ATOMIC);
+	if (error)
+		err("bcm5974: button urb failed: %d", error);
+}
+
+static void bcm5974_irq_trackpad(struct urb *urb)
+{
+	struct bcm5974 *dev = urb->context;
+	int error;
+
+	switch (urb->status) {
+	case 0:
+		break;
+	case -EOVERFLOW:
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		dbg("bcm5974: trackpad urb shutting down: %d", urb->status);
+		return;
+	default:
+		dbg("bcm5974: trackpad urb status: %d", urb->status);
+		goto exit;
+	}
+
+	/* control response ignored */
+	if (dev->tp_urb->actual_length == 2)
+		goto exit;
+
+	if (report_tp_state(dev, dev->tp_urb->actual_length))
+		dprintk(1, "bcm5974: bad trackpad package, length: %d\n",
+			dev->tp_urb->actual_length);
+
+exit:
+	error = usb_submit_urb(dev->tp_urb, GFP_ATOMIC);
+	if (error)
+		err("bcm5974: trackpad urb failed: %d", error);
+}
+
+/*
+ * The Wellspring trackpad, like many recent Apple trackpads, share
+ * the usb device with the keyboard. Since keyboards are usually
+ * handled by the HID system, the device ends up being handled by two
+ * modules. Setting up the device therefore becomes slightly
+ * complicated. To enable multitouch features, a mode switch is
+ * required, which is usually applied via the control interface of the
+ * device.  It can be argued where this switch should take place. In
+ * some drivers, like appletouch, the switch is made during
+ * probe. However, the hid module may also alter the state of the
+ * device, resulting in trackpad malfunction under certain
+ * circumstances. To get around this problem, there is at least one
+ * example that utilizes the USB_QUIRK_RESET_RESUME quirk in order to
+ * recieve a reset_resume request rather than the normal resume.
+ * Since the implementation of reset_resume is equal to mode switch
+ * plus start_traffic, it seems easier to always do the switch when
+ * starting traffic on the device.
+ */
+static int bcm5974_start_traffic(struct bcm5974 *dev)
+{
+	if (bcm5974_wellspring_mode(dev)) {
+		dprintk(1, "bcm5974: mode switch failed\n");
+		goto error;
+	}
+
+	if (usb_submit_urb(dev->bt_urb, GFP_KERNEL))
+		goto error;
+
+	if (usb_submit_urb(dev->tp_urb, GFP_KERNEL))
+		goto err_kill_bt;
+
+	return 0;
+
+err_kill_bt:
+	usb_kill_urb(dev->bt_urb);
+error:
+	return -EIO;
+}
+
+static void bcm5974_pause_traffic(struct bcm5974 *dev)
+{
+	usb_kill_urb(dev->tp_urb);
+	usb_kill_urb(dev->bt_urb);
+}
+
+/*
+ * The code below implements open/close and manual suspend/resume.
+ * All functions may be called in random order.
+ *
+ * Opening a suspended device fails with EACCES - permission denied.
+ *
+ * Failing a resume leaves the device resumed but closed.
+ */
+static int bcm5974_open(struct input_dev *input)
+{
+	struct bcm5974 *dev = input_get_drvdata(input);
+	int error;
+
+	mutex_lock(&dev->pm_mutex);
+
+	error = bcm5974_start_traffic(dev);
+	if (!error)
+		dev->opened = 1;
+
+	mutex_unlock(&dev->pm_mutex);
+
+	return error;
+}
+
+static void bcm5974_close(struct input_dev *input)
+{
+	struct bcm5974 *dev = input_get_drvdata(input);
+
+	mutex_lock(&dev->pm_mutex);
+
+	bcm5974_pause_traffic(dev);
+	dev->opened = 0;
+
+	mutex_unlock(&dev->pm_mutex);
+}
+
+static int bcm5974_suspend(struct usb_interface *iface, pm_message_t message)
+{
+	struct bcm5974 *dev = usb_get_intfdata(iface);
+
+	mutex_lock(&dev->pm_mutex);
+
+	if (dev->opened)
+		bcm5974_pause_traffic(dev);
+
+	mutex_unlock(&dev->pm_mutex);
+
+	return 0;
+}
+
+static int bcm5974_resume(struct usb_interface *iface)
+{
+	struct bcm5974 *dev = usb_get_intfdata(iface);
+	int error = 0;
+
+	mutex_lock(&dev->pm_mutex);
+
+	if (dev->opened)
+		error = bcm5974_start_traffic(dev);
+
+	mutex_unlock(&dev->pm_mutex);
+
+	return error;
+}
+
+static int bcm5974_probe(struct usb_interface *iface,
+			 const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(iface);
+	const struct bcm5974_config *cfg;
+	struct bcm5974 *dev;
+	struct input_dev *input_dev;
+	int error = -ENOMEM;
+
+	/* find the product index */
+	cfg = bcm5974_get_config(udev);
+
+	/* allocate memory for our device state and initialize it */
+	dev = kzalloc(sizeof(struct bcm5974), GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (!dev || !input_dev) {
+		err("bcm5974: out of memory");
+		goto err_free_devs;
+	}
+
+	dev->udev = udev;
+	dev->input = input_dev;
+	dev->cfg = *cfg;
+	mutex_init(&dev->pm_mutex);
+
+	/* setup urbs */
+	dev->bt_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->bt_urb)
+		goto err_free_devs;
+
+	dev->tp_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->tp_urb)
+		goto err_free_bt_urb;
+
+	dev->bt_data = usb_buffer_alloc(dev->udev,
+					dev->cfg.bt_datalen, GFP_KERNEL,
+					&dev->bt_urb->transfer_dma);
+	if (!dev->bt_data)
+		goto err_free_urb;
+
+	dev->tp_data = usb_buffer_alloc(dev->udev,
+					dev->cfg.tp_datalen, GFP_KERNEL,
+					&dev->tp_urb->transfer_dma);
+	if (!dev->tp_data)
+		goto err_free_bt_buffer;
+
+	usb_fill_int_urb(dev->bt_urb, udev,
+			 usb_rcvintpipe(udev, cfg->bt_ep),
+			 dev->bt_data, dev->cfg.bt_datalen,
+			 bcm5974_irq_button, dev, 1);
+
+	usb_fill_int_urb(dev->tp_urb, udev,
+			 usb_rcvintpipe(udev, cfg->tp_ep),
+			 dev->tp_data, dev->cfg.tp_datalen,
+			 bcm5974_irq_trackpad, dev, 1);
+
+	/* create bcm5974 device */
+	usb_make_path(udev, dev->phys, sizeof(dev->phys));
+	strlcat(dev->phys, "/input0", sizeof(dev->phys));
+
+	input_dev->name = "bcm5974";
+	input_dev->phys = dev->phys;
+	usb_to_input_id(dev->udev, &input_dev->id);
+	input_dev->dev.parent = &iface->dev;
+
+	input_set_drvdata(input_dev, dev);
+
+	input_dev->open = bcm5974_open;
+	input_dev->close = bcm5974_close;
+
+	setup_events_to_report(input_dev, cfg);
+
+	error = input_register_device(dev->input);
+	if (error)
+		goto err_free_buffer;
+
+	/* save our data pointer in this interface device */
+	usb_set_intfdata(iface, dev);
+
+	return 0;
+
+err_free_buffer:
+	usb_buffer_free(dev->udev, dev->cfg.tp_datalen,
+		dev->tp_data, dev->tp_urb->transfer_dma);
+err_free_bt_buffer:
+	usb_buffer_free(dev->udev, dev->cfg.bt_datalen,
+		dev->bt_data, dev->bt_urb->transfer_dma);
+err_free_urb:
+	usb_free_urb(dev->tp_urb);
+err_free_bt_urb:
+	usb_free_urb(dev->bt_urb);
+err_free_devs:
+	usb_set_intfdata(iface, NULL);
+	input_free_device(input_dev);
+	kfree(dev);
+	return error;
+}
+
+static void bcm5974_disconnect(struct usb_interface *iface)
+{
+	struct bcm5974 *dev = usb_get_intfdata(iface);
+
+	usb_set_intfdata(iface, NULL);
+
+	input_unregister_device(dev->input);
+	usb_buffer_free(dev->udev, dev->cfg.tp_datalen,
+			dev->tp_data, dev->tp_urb->transfer_dma);
+	usb_buffer_free(dev->udev, dev->cfg.bt_datalen,
+			dev->bt_data, dev->bt_urb->transfer_dma);
+	usb_free_urb(dev->tp_urb);
+	usb_free_urb(dev->bt_urb);
+	kfree(dev);
+}
+
+static struct usb_driver bcm5974_driver = {
+	.name			= "bcm5974",
+	.probe			= bcm5974_probe,
+	.disconnect		= bcm5974_disconnect,
+	.suspend		= bcm5974_suspend,
+	.resume			= bcm5974_resume,
+	.reset_resume		= bcm5974_resume,
+	.id_table		= bcm5974_table,
+};
+
+static int __init bcm5974_init(void)
+{
+	return usb_register(&bcm5974_driver);
+}
+
+static void __exit bcm5974_exit(void)
+{
+	usb_deregister(&bcm5974_driver);
+}
+
+module_init(bcm5974_init);
+module_exit(bcm5974_exit);
+