/*
 * 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
/* Macbook5,1 (unibody), aka wellspring3 */
#define USB_DEVICE_ID_APPLE_WELLSPRING3_ANSI    0x0236
#define USB_DEVICE_ID_APPLE_WELLSPRING3_ISO     0x0237
#define USB_DEVICE_ID_APPLE_WELLSPRING3_JIS     0x0238
/* MacbookAir3,2 (unibody), aka wellspring5 */
#define USB_DEVICE_ID_APPLE_WELLSPRING4_ANSI    0x023f
#define USB_DEVICE_ID_APPLE_WELLSPRING4_ISO     0x0240
#define USB_DEVICE_ID_APPLE_WELLSPRING4_JIS     0x0241
/* MacbookAir3,1 (unibody), aka wellspring4 */
#define USB_DEVICE_ID_APPLE_WELLSPRING4A_ANSI   0x0242
#define USB_DEVICE_ID_APPLE_WELLSPRING4A_ISO    0x0243
#define USB_DEVICE_ID_APPLE_WELLSPRING4A_JIS    0x0244
/* Macbook8 (unibody, March 2011) */
#define USB_DEVICE_ID_APPLE_WELLSPRING5_ANSI    0x0245
#define USB_DEVICE_ID_APPLE_WELLSPRING5_ISO     0x0246
#define USB_DEVICE_ID_APPLE_WELLSPRING5_JIS     0x0247

#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),
        /* Macbook5,1 */
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING3_ANSI),
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING3_ISO),
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING3_JIS),
        /* MacbookAir3,2 */
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING4_ANSI),
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING4_ISO),
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING4_JIS),
        /* MacbookAir3,1 */
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING4A_ANSI),
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING4A_ISO),
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING4A_JIS),
        /* MacbookPro8 */
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING5_ANSI),
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING5_ISO),
        BCM5974_DEVICE(USB_DEVICE_ID_APPLE_WELLSPRING5_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 types */
enum tp_type {
        TYPE1,                  /* plain trackpad */
        TYPE2                   /* button integrated in trackpad */
};

/* trackpad finger data offsets, le16-aligned */
#define FINGER_TYPE1            (13 * sizeof(__le16))
#define FINGER_TYPE2            (15 * sizeof(__le16))

/* trackpad button data offsets */
#define BUTTON_TYPE2            15

/* list of device capability bits */
#define HAS_INTEGRATED_BUTTON   1

/* trackpad finger structure, le16-aligned */
struct tp_finger {
        __le16 origin;          /* zero when switching track finger */
        __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 */
} __attribute__((packed,aligned(2)));

/* trackpad finger data size, empirically at least ten fingers */
#define SIZEOF_FINGER           sizeof(struct tp_finger)
#define SIZEOF_ALL_FINGERS      (16 * SIZEOF_FINGER)
#define MAX_FINGER_ORIENTATION  16384

/* 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 caps;               /* device capability bitmask */
        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 */
        enum tp_type tp_type;   /* type of trackpad interface */
        int tp_offset;          /* offset to trackpad finger data */
        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 usb_interface *intf;     /* our interface */
        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 */
        u8 *tp_data;                    /* trackpad transferred data */
        int fingers;                    /* number of fingers on trackpad */
};

/* 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 */

/* pressure thresholds */
#define PRESSURE_LOW    (2 * DIM_PRESSURE / SN_PRESSURE)
#define PRESSURE_HIGH   (3 * PRESSURE_LOW)

/* 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,
                0,
                0x84, sizeof(struct bt_data),
                0x81, TYPE1, FINGER_TYPE1, FINGER_TYPE1 + SIZEOF_ALL_FINGERS,
                { 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,
                0,
                0x84, sizeof(struct bt_data),
                0x81, TYPE1, FINGER_TYPE1, FINGER_TYPE1 + SIZEOF_ALL_FINGERS,
                { 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 }
        },
        {
                USB_DEVICE_ID_APPLE_WELLSPRING3_ANSI,
                USB_DEVICE_ID_APPLE_WELLSPRING3_ISO,
                USB_DEVICE_ID_APPLE_WELLSPRING3_JIS,
                HAS_INTEGRATED_BUTTON,
                0x84, sizeof(struct bt_data),
                0x81, TYPE2, FINGER_TYPE2, FINGER_TYPE2 + SIZEOF_ALL_FINGERS,
                { DIM_PRESSURE, DIM_PRESSURE / SN_PRESSURE, 0, 300 },
                { DIM_WIDTH, DIM_WIDTH / SN_WIDTH, 0, 2048 },
                { DIM_X, DIM_X / SN_COORD, -4460, 5166 },
                { DIM_Y, DIM_Y / SN_COORD, -75, 6700 }
        },
        {
                USB_DEVICE_ID_APPLE_WELLSPRING4_ANSI,
                USB_DEVICE_ID_APPLE_WELLSPRING4_ISO,
                USB_DEVICE_ID_APPLE_WELLSPRING4_JIS,
                HAS_INTEGRATED_BUTTON,
                0x84, sizeof(struct bt_data),
                0x81, TYPE2, FINGER_TYPE2, FINGER_TYPE2 + SIZEOF_ALL_FINGERS,
                { DIM_PRESSURE, DIM_PRESSURE / SN_PRESSURE, 0, 300 },
                { DIM_WIDTH, DIM_WIDTH / SN_WIDTH, 0, 2048 },
                { DIM_X, DIM_X / SN_COORD, -4620, 5140 },
                { DIM_Y, DIM_Y / SN_COORD, -150, 6600 }
        },
        {
                USB_DEVICE_ID_APPLE_WELLSPRING4A_ANSI,
                USB_DEVICE_ID_APPLE_WELLSPRING4A_ISO,
                USB_DEVICE_ID_APPLE_WELLSPRING4A_JIS,
                HAS_INTEGRATED_BUTTON,
                0x84, sizeof(struct bt_data),
                0x81, TYPE2, FINGER_TYPE2, FINGER_TYPE2 + SIZEOF_ALL_FINGERS,
                { DIM_PRESSURE, DIM_PRESSURE / SN_PRESSURE, 0, 300 },
                { DIM_WIDTH, DIM_WIDTH / SN_WIDTH, 0, 2048 },
                { DIM_X, DIM_X / SN_COORD, -4616, 5112 },
                { DIM_Y, DIM_Y / SN_COORD, -142, 5234 }
        },
        {
                USB_DEVICE_ID_APPLE_WELLSPRING5_ANSI,
                USB_DEVICE_ID_APPLE_WELLSPRING5_ISO,
                USB_DEVICE_ID_APPLE_WELLSPRING5_JIS,
                HAS_INTEGRATED_BUTTON,
                0x84, sizeof(struct bt_data),
                0x81, TYPE2, FINGER_TYPE2, FINGER_TYPE2 + SIZEOF_ALL_FINGERS,
                { DIM_PRESSURE, DIM_PRESSURE / SN_PRESSURE, 0, 300 },
                { DIM_WIDTH, DIM_WIDTH / SN_WIDTH, 0, 2048 },
                { DIM_X, DIM_X / SN_COORD, -4415, 5050 },
                { DIM_Y, DIM_Y / SN_COORD, -55, 6680 }
        },
        {}
};

/* 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);

        /* finger touch area */
        input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
                             cfg->w.devmin, cfg->w.devmax, 0, 0);
        input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR,
                             cfg->w.devmin, cfg->w.devmax, 0, 0);
        /* finger approach area */
        input_set_abs_params(input_dev, ABS_MT_WIDTH_MAJOR,
                             cfg->w.devmin, cfg->w.devmax, 0, 0);
        input_set_abs_params(input_dev, ABS_MT_WIDTH_MINOR,
                             cfg->w.devmin, cfg->w.devmax, 0, 0);
        /* finger orientation */
        input_set_abs_params(input_dev, ABS_MT_ORIENTATION,
                             -MAX_FINGER_ORIENTATION,
                             MAX_FINGER_ORIENTATION, 0, 0);
        /* finger position */
        input_set_abs_params(input_dev, ABS_MT_POSITION_X,
                             cfg->x.devmin, cfg->x.devmax, 0, 0);
        input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
                             cfg->y.devmin, cfg->y.devmax, 0, 0);

        __set_bit(EV_KEY, input_dev->evbit);
        __set_bit(BTN_TOUCH, input_dev->keybit);
        __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_TOOL_QUADTAP, input_dev->keybit);
        __set_bit(BTN_LEFT, input_dev->keybit);

        input_set_events_per_packet(input_dev, 60);
}

/* 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;

        dprintk(7,
                "bcm5974: button data: %x %x %x %x\n",
                dev->bt_data->unknown1, dev->bt_data->button,
                dev->bt_data->rel_x, dev->bt_data->rel_y);

        input_report_key(dev->input, BTN_LEFT, dev->bt_data->button);
        input_sync(dev->input);

        return 0;
}

static void report_finger_data(struct input_dev *input,
                               const struct bcm5974_config *cfg,
                               const struct tp_finger *f)
{
        input_report_abs(input, ABS_MT_TOUCH_MAJOR,
                         raw2int(f->force_major) << 1);
        input_report_abs(input, ABS_MT_TOUCH_MINOR,
                         raw2int(f->force_minor) << 1);
        input_report_abs(input, ABS_MT_WIDTH_MAJOR,
                         raw2int(f->size_major) << 1);
        input_report_abs(input, ABS_MT_WIDTH_MINOR,
                         raw2int(f->size_minor) << 1);
        input_report_abs(input, ABS_MT_ORIENTATION,
                         MAX_FINGER_ORIENTATION - raw2int(f->orientation));
        input_report_abs(input, ABS_MT_POSITION_X, raw2int(f->abs_x));
        input_report_abs(input, ABS_MT_POSITION_Y,
                         cfg->y.devmin + cfg->y.devmax - raw2int(f->abs_y));
        input_mt_sync(input);
}

/* 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;
        struct input_dev *input = dev->input;
        int raw_p, raw_w, raw_x, raw_y, raw_n, i;
        int ptest, origin, ibt = 0, nmin = 0, nmax = 0;
        int abs_p = 0, abs_w = 0, abs_x = 0, abs_y = 0;

        if (size < c->tp_offset || (size - c->tp_offset) % SIZEOF_FINGER != 0)
                return -EIO;

        /* finger data, le16-aligned */
        f = (const struct tp_finger *)(dev->tp_data + c->tp_offset);
        raw_n = (size - c->tp_offset) / SIZEOF_FINGER;

        /* always track the first finger; when detached, start over */
        if (raw_n) {

                /* report raw trackpad data */
                for (i = 0; i < raw_n; i++)
                        report_finger_data(input, c, &f[i]);

                raw_p = raw2int(f->force_major);
                raw_w = raw2int(f->size_major);
                raw_x = raw2int(f->abs_x);
                raw_y = raw2int(f->abs_y);

                dprintk(9,
                        "bcm5974: "
                        "raw: p: %+05d w: %+05d x: %+05d y: %+05d n: %d\n",
                        raw_p, raw_w, raw_x, raw_y, raw_n);

                ptest = int2bound(&c->p, raw_p);
                origin = raw2int(f->origin);

                /* while tracking finger still valid, count all fingers */
                if (ptest > PRESSURE_LOW && origin) {
                        abs_p = ptest;
                        abs_w = int2bound(&c->w, raw_w);
                        abs_x = int2bound(&c->x, raw_x - c->x.devmin);
                        abs_y = int2bound(&c->y, c->y.devmax - raw_y);
                        while (raw_n--) {
                                ptest = int2bound(&c->p,
                                                  raw2int(f->force_major));
                                if (ptest > PRESSURE_LOW)
                                        nmax++;
                                if (ptest > PRESSURE_HIGH)
                                        nmin++;
                                f++;
                        }
                }
        }

        /* set the integrated button if applicable */
        if (c->tp_type == TYPE2)
                ibt = raw2int(dev->tp_data[BUTTON_TYPE2]);

        if (dev->fingers < nmin)
                dev->fingers = nmin;
        if (dev->fingers > nmax)
                dev->fingers = nmax;

        input_report_key(input, BTN_TOUCH, dev->fingers > 0);
        input_report_key(input, BTN_TOOL_FINGER, dev->fingers == 1);
        input_report_key(input, BTN_TOOL_DOUBLETAP, dev->fingers == 2);
        input_report_key(input, BTN_TOOL_TRIPLETAP, dev->fingers == 3);
        input_report_key(input, BTN_TOOL_QUADTAP, dev->fingers > 3);

        input_report_abs(input, ABS_PRESSURE, abs_p);
        input_report_abs(input, ABS_TOOL_WIDTH, abs_w);

        if (abs_p) {
                input_report_abs(input, ABS_X, abs_x);
                input_report_abs(input, ABS_Y, abs_y);

                dprintk(8,
                        "bcm5974: abs: p: %+05d w: %+05d x: %+05d y: %+05d "
                        "nmin: %d nmax: %d n: %d ibt: %d\n", abs_p, abs_w,
                        abs_x, abs_y, nmin, nmax, dev->fingers, ibt);

        }

        /* type 2 reports button events via ibt only */
        if (c->tp_type == TYPE2)
                input_report_key(input, BTN_LEFT, ibt);

        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
#define BCM5974_WELLSPRING_MODE_NORMAL_VALUE            0x08

static int bcm5974_wellspring_mode(struct bcm5974 *dev, bool on)
{
        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] = on ?
                BCM5974_WELLSPRING_MODE_VENDOR_VALUE :
                BCM5974_WELLSPRING_MODE_NORMAL_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 %s mode.\n",
                on ? "wellspring" : "normal");

 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
 * receive 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)
{
        int error;

        error = bcm5974_wellspring_mode(dev, true);
        if (error) {
                dprintk(1, "bcm5974: mode switch failed\n");
                goto err_out;
        }

        error = usb_submit_urb(dev->bt_urb, GFP_KERNEL);
        if (error)
                goto err_reset_mode;

        error = usb_submit_urb(dev->tp_urb, GFP_KERNEL);
        if (error)
                goto err_kill_bt;

        return 0;

err_kill_bt:
        usb_kill_urb(dev->bt_urb);
err_reset_mode:
        bcm5974_wellspring_mode(dev, false);
err_out:
        return error;
}

static void bcm5974_pause_traffic(struct bcm5974 *dev)
{
        usb_kill_urb(dev->tp_urb);
        usb_kill_urb(dev->bt_urb);
        bcm5974_wellspring_mode(dev, false);
}

/*
 * 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;

        error = usb_autopm_get_interface(dev->intf);
        if (error)
                return error;

        mutex_lock(&dev->pm_mutex);

        error = bcm5974_start_traffic(dev);
        if (!error)
                dev->opened = 1;

        mutex_unlock(&dev->pm_mutex);

        if (error)
                usb_autopm_put_interface(dev->intf);

        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);

        usb_autopm_put_interface(dev->intf);
}

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->intf = iface;
        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_alloc_coherent(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_alloc_coherent(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);
        /* report driver capabilities via the version field */
        input_dev->id.version = cfg->caps;
        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_free_coherent(dev->udev, dev->cfg.tp_datalen,
                dev->tp_data, dev->tp_urb->transfer_dma);
err_free_bt_buffer:
        usb_free_coherent(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_free_coherent(dev->udev, dev->cfg.tp_datalen,
                          dev->tp_data, dev->tp_urb->transfer_dma);
        usb_free_coherent(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,
        .id_table               = bcm5974_table,
        .supports_autosuspend   = 1,
};

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);