/* Siemens ID Mouse driver v0.6

  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.

  Copyright (C) 2004-5 by Florian 'Floe' Echtler  <echtler@fs.tum.de>
                      and Andreas  'ad'  Deresch <aderesch@fs.tum.de>

  Derived from the USB Skeleton driver 1.1,
  Copyright (C) 2003 Greg Kroah-Hartman (greg@kroah.com)

  Additional information provided by Martin Reising
  <Martin.Reising@natural-computing.de>

*/

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <asm/uaccess.h>
#include <linux/usb.h>

/* image constants */
#define WIDTH 225
#define HEIGHT 289
#define HEADER "P5 225 289 255 "
#define IMGSIZE ((WIDTH * HEIGHT) + sizeof(HEADER)-1)

/* version information */
#define DRIVER_VERSION "0.6"
#define DRIVER_SHORT   "idmouse"
#define DRIVER_AUTHOR  "Florian 'Floe' Echtler <echtler@fs.tum.de>"
#define DRIVER_DESC    "Siemens ID Mouse FingerTIP Sensor Driver"

/* minor number for misc USB devices */
#define USB_IDMOUSE_MINOR_BASE 132

/* vendor and device IDs */
#define ID_SIEMENS 0x0681
#define ID_IDMOUSE 0x0005
#define ID_CHERRY  0x0010

/* device ID table */
static struct usb_device_id idmouse_table[] = {
        {USB_DEVICE(ID_SIEMENS, ID_IDMOUSE)}, /* Siemens ID Mouse (Professional) */
        {USB_DEVICE(ID_SIEMENS, ID_CHERRY )}, /* Cherry FingerTIP ID Board       */
        {}                                    /* terminating null entry          */
};

/* sensor commands */
#define FTIP_RESET   0x20
#define FTIP_ACQUIRE 0x21
#define FTIP_RELEASE 0x22
#define FTIP_BLINK   0x23  /* LSB of value = blink pulse width */
#define FTIP_SCROLL  0x24

#define ftip_command(dev, command, value, index) \
        usb_control_msg (dev->udev, usb_sndctrlpipe (dev->udev, 0), command, \
        USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT, value, index, NULL, 0, 1000)

MODULE_DEVICE_TABLE(usb, idmouse_table);
static DEFINE_MUTEX(open_disc_mutex);

/* structure to hold all of our device specific stuff */
struct usb_idmouse {

        struct usb_device *udev; /* save off the usb device pointer */
        struct usb_interface *interface; /* the interface for this device */

        unsigned char *bulk_in_buffer; /* the buffer to receive data */
        size_t bulk_in_size; /* the maximum bulk packet size */
        size_t orig_bi_size; /* same as above, but reported by the device */
        __u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */

        int open; /* if the port is open or not */
        int present; /* if the device is not disconnected */
        struct mutex lock; /* locks this structure */

};

/* local function prototypes */
static ssize_t idmouse_read(struct file *file, char __user *buffer,
                                size_t count, loff_t * ppos);

static int idmouse_open(struct inode *inode, struct file *file);
static int idmouse_release(struct inode *inode, struct file *file);

static int idmouse_probe(struct usb_interface *interface,
                                const struct usb_device_id *id);

static void idmouse_disconnect(struct usb_interface *interface);

/* file operation pointers */
static const struct file_operations idmouse_fops = {
        .owner = THIS_MODULE,
        .read = idmouse_read,
        .open = idmouse_open,
        .release = idmouse_release,
};

/* class driver information */
static struct usb_class_driver idmouse_class = {
        .name = "idmouse%d",
        .fops = &idmouse_fops,
        .minor_base = USB_IDMOUSE_MINOR_BASE,
};

/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver idmouse_driver = {
        .name = DRIVER_SHORT,
        .probe = idmouse_probe,
        .disconnect = idmouse_disconnect,
        .id_table = idmouse_table,
};

static int idmouse_create_image(struct usb_idmouse *dev)
{
        int bytes_read;
        int bulk_read;
        int result;

        memcpy(dev->bulk_in_buffer, HEADER, sizeof(HEADER)-1);
        bytes_read = sizeof(HEADER)-1;

        /* reset the device and set a fast blink rate */
        result = ftip_command(dev, FTIP_RELEASE, 0, 0);
        if (result < 0)
                goto reset;
        result = ftip_command(dev, FTIP_BLINK,   1, 0);
        if (result < 0)
                goto reset;

        /* initialize the sensor - sending this command twice */
        /* significantly reduces the rate of failed reads     */
        result = ftip_command(dev, FTIP_ACQUIRE, 0, 0);
        if (result < 0)
                goto reset;
        result = ftip_command(dev, FTIP_ACQUIRE, 0, 0);
        if (result < 0)
                goto reset;

        /* start the readout - sending this command twice */
        /* presumably enables the high dynamic range mode */
        result = ftip_command(dev, FTIP_RESET,   0, 0);
        if (result < 0)
                goto reset;
        result = ftip_command(dev, FTIP_RESET,   0, 0);
        if (result < 0)
                goto reset;

        /* loop over a blocking bulk read to get data from the device */
        while (bytes_read < IMGSIZE) {
                result = usb_bulk_msg (dev->udev,
                                usb_rcvbulkpipe (dev->udev, dev->bulk_in_endpointAddr),
                                dev->bulk_in_buffer + bytes_read,
                                dev->bulk_in_size, &bulk_read, 5000);
                if (result < 0) {
                        /* Maybe this error was caused by the increased packet size? */
                        /* Reset to the original value and tell userspace to retry.  */
                        if (dev->bulk_in_size != dev->orig_bi_size) {
                                dev->bulk_in_size = dev->orig_bi_size;
                                result = -EAGAIN;
                        }
                        break;
                }
                if (signal_pending(current)) {
                        result = -EINTR;
                        break;
                }
                bytes_read += bulk_read;
        }

        /* reset the device */
reset:
        ftip_command(dev, FTIP_RELEASE, 0, 0);

        /* check for valid image */
        /* right border should be black (0x00) */
        for (bytes_read = sizeof(HEADER)-1 + WIDTH-1; bytes_read < IMGSIZE; bytes_read += WIDTH)
                if (dev->bulk_in_buffer[bytes_read] != 0x00)
                        return -EAGAIN;

        /* lower border should be white (0xFF) */
        for (bytes_read = IMGSIZE-WIDTH; bytes_read < IMGSIZE-1; bytes_read++)
                if (dev->bulk_in_buffer[bytes_read] != 0xFF)
                        return -EAGAIN;

        /* should be IMGSIZE == 65040 */
        dbg("read %d bytes fingerprint data", bytes_read);
        return result;
}

static inline void idmouse_delete(struct usb_idmouse *dev)
{
        kfree(dev->bulk_in_buffer);
        kfree(dev);
}

static int idmouse_open(struct inode *inode, struct file *file)
{
        struct usb_idmouse *dev;
        struct usb_interface *interface;
        int result;

        /* get the interface from minor number and driver information */
        interface = usb_find_interface (&idmouse_driver, iminor (inode));
        if (!interface)
                return -ENODEV;

        mutex_lock(&open_disc_mutex);
        /* get the device information block from the interface */
        dev = usb_get_intfdata(interface);
        if (!dev) {
                mutex_unlock(&open_disc_mutex);
                return -ENODEV;
        }

        /* lock this device */
        mutex_lock(&dev->lock);
        mutex_unlock(&open_disc_mutex);

        /* check if already open */
        if (dev->open) {

                /* already open, so fail */
                result = -EBUSY;

        } else {

                /* create a new image and check for success */
                result = idmouse_create_image (dev);
                if (result)
                        goto error;

                /* increment our usage count for the driver */
                ++dev->open;

                /* save our object in the file's private structure */
                file->private_data = dev;

        } 

error:

        /* unlock this device */
        mutex_unlock(&dev->lock);
        return result;
}

static int idmouse_release(struct inode *inode, struct file *file)
{
        struct usb_idmouse *dev;

        dev = file->private_data;

        if (dev == NULL)
                return -ENODEV;

        mutex_lock(&open_disc_mutex);
        /* lock our device */
        mutex_lock(&dev->lock);

        /* are we really open? */
        if (dev->open <= 0) {
                mutex_unlock(&dev->lock);
                mutex_unlock(&open_disc_mutex);
                return -ENODEV;
        }

        --dev->open;

        if (!dev->present) {
                /* the device was unplugged before the file was released */
                mutex_unlock(&dev->lock);
                mutex_unlock(&open_disc_mutex);
                idmouse_delete(dev);
        } else {
                mutex_unlock(&dev->lock);
                mutex_unlock(&open_disc_mutex);
        }
        return 0;
}

static ssize_t idmouse_read(struct file *file, char __user *buffer, size_t count,
                                loff_t * ppos)
{
        struct usb_idmouse *dev = file->private_data;
        int result;

        /* lock this object */
        mutex_lock(&dev->lock);

        /* verify that the device wasn't unplugged */
        if (!dev->present) {
                mutex_unlock(&dev->lock);
                return -ENODEV;
        }

        result = simple_read_from_buffer(buffer, count, ppos,
                                        dev->bulk_in_buffer, IMGSIZE);
        /* unlock the device */
        mutex_unlock(&dev->lock);
        return result;
}

static int idmouse_probe(struct usb_interface *interface,
                                const struct usb_device_id *id)
{
        struct usb_device *udev = interface_to_usbdev(interface);
        struct usb_idmouse *dev;
        struct usb_host_interface *iface_desc;
        struct usb_endpoint_descriptor *endpoint;
        int result;

        /* check if we have gotten the data or the hid interface */
        iface_desc = &interface->altsetting[0];
        if (iface_desc->desc.bInterfaceClass != 0x0A)
                return -ENODEV;

        /* allocate memory for our device state and initialize it */
        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (dev == NULL)
                return -ENOMEM;

        mutex_init(&dev->lock);
        dev->udev = udev;
        dev->interface = interface;

        /* set up the endpoint information - use only the first bulk-in endpoint */
        endpoint = &iface_desc->endpoint[0].desc;
        if (!dev->bulk_in_endpointAddr && usb_endpoint_is_bulk_in(endpoint)) {
                /* we found a bulk in endpoint */
                dev->orig_bi_size = le16_to_cpu(endpoint->wMaxPacketSize);
                dev->bulk_in_size = 0x200; /* works _much_ faster */
                dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
                dev->bulk_in_buffer =
                        kmalloc(IMGSIZE + dev->bulk_in_size, GFP_KERNEL);

                if (!dev->bulk_in_buffer) {
                        err("Unable to allocate input buffer.");
                        idmouse_delete(dev);
                        return -ENOMEM;
                }
        }

        if (!(dev->bulk_in_endpointAddr)) {
                err("Unable to find bulk-in endpoint.");
                idmouse_delete(dev);
                return -ENODEV;
        }
        /* allow device read, write and ioctl */
        dev->present = 1;

        /* we can register the device now, as it is ready */
        usb_set_intfdata(interface, dev);
        result = usb_register_dev(interface, &idmouse_class);
        if (result) {
                /* something prevented us from registering this device */
                err("Unble to allocate minor number.");
                usb_set_intfdata(interface, NULL);
                idmouse_delete(dev);
                return result;
        }

        /* be noisy */
        dev_info(&interface->dev,"%s now attached\n",DRIVER_DESC);

        return 0;
}

static void idmouse_disconnect(struct usb_interface *interface)
{
        struct usb_idmouse *dev;

        /* get device structure */
        dev = usb_get_intfdata(interface);

        /* give back our minor */
        usb_deregister_dev(interface, &idmouse_class);

        mutex_lock(&open_disc_mutex);
        usb_set_intfdata(interface, NULL);
        /* lock the device */
        mutex_lock(&dev->lock);
        mutex_unlock(&open_disc_mutex);

        /* prevent device read, write and ioctl */
        dev->present = 0;

        /* if the device is opened, idmouse_release will clean this up */
        if (!dev->open) {
                mutex_unlock(&dev->lock);
                idmouse_delete(dev);
        } else {
                /* unlock */
                mutex_unlock(&dev->lock);
        }

        dev_info(&interface->dev, "disconnected\n");
}

static int __init usb_idmouse_init(void)
{
        int result;

        printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
               DRIVER_DESC "\n");

        /* register this driver with the USB subsystem */
        result = usb_register(&idmouse_driver);
        if (result)
                err("Unable to register device (error %d).", result);

        return result;
}

static void __exit usb_idmouse_exit(void)
{
        /* deregister this driver with the USB subsystem */
        usb_deregister(&idmouse_driver);
}

module_init(usb_idmouse_init);
module_exit(usb_idmouse_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");