uss720.c

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/*****************************************************************************/

/*
 *  uss720.c  --  USS720 USB Parport Cable.
 *
 *  Copyright (C) 1999, 2005, 2010
 *      Thomas Sailer ([email protected])
 *
 *  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.
 *
 *  Based on parport_pc.c
 *
 *  History:
 *   0.1  04.08.1999  Created
 *   0.2  07.08.1999  Some fixes mainly suggested by Tim Waugh
 *            Interrupt handling currently disabled because
 *            usb_request_irq crashes somewhere within ohci.c
 *            for no apparent reason (that is for me, anyway)
 *            ECP currently untested
 *   0.3  10.08.1999  fixing merge errors
 *   0.4  13.08.1999  Added Vendor/Product ID of Brad Hard's cable
 *   0.5  20.09.1999  usb_control_msg wrapper used
 *        Nov01.2000  usb_device_table support by Adam J. Richter
 *        08.04.2001  Identify version on module load.  gb
 *   0.6  02.09.2005  Fix "scheduling in interrupt" problem by making save/restore
 *                    context asynchronous
 *
 */

/*****************************************************************************/

#include <linux/module.h>
#include <linux/socket.h>
#include <linux/parport.h>
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/delay.h>
#include <linux/completion.h>
#include <linux/kref.h>
#include <linux/slab.h>

/*
 * Version Information
 */
#define DRIVER_VERSION "v0.6"
#define DRIVER_AUTHOR "Thomas M. Sailer, [email protected]"
#define DRIVER_DESC "USB Parport Cable driver for Cables using the Lucent Technologies USS720 Chip"

/* --------------------------------------------------------------------- */

struct parport_uss720_private {
    struct usb_device *usbdev;
    struct parport *pp;
    struct kref ref_count;
    __u8 reg[7];  /* USB registers */
    struct list_head asynclist;
    spinlock_t asynclock;
};

struct uss720_async_request {
    struct parport_uss720_private *priv;
    struct kref ref_count;
    struct list_head asynclist;
    struct completion compl;
    struct urb *urb;
    struct usb_ctrlrequest dr;
    __u8 reg[7];
};

/* --------------------------------------------------------------------- */

static void destroy_priv(struct kref *kref)
{
    struct parport_uss720_private *priv = container_of(kref, struct parport_uss720_private, ref_count);

    dev_dbg(&priv->usbdev->dev, "destroying priv datastructure\n");
    usb_put_dev(priv->usbdev);
    kfree(priv);
}

static void destroy_async(struct kref *kref)
{
    struct uss720_async_request *rq = container_of(kref, struct uss720_async_request, ref_count);
    struct parport_uss720_private *priv = rq->priv;
    unsigned long flags;

    if (likely(rq->urb))
        usb_free_urb(rq->urb);
    spin_lock_irqsave(&priv->asynclock, flags);
    list_del_init(&rq->asynclist);
    spin_unlock_irqrestore(&priv->asynclock, flags);
    kfree(rq);
    kref_put(&priv->ref_count, destroy_priv);
}

/* --------------------------------------------------------------------- */

static void async_complete(struct urb *urb)
{
    struct uss720_async_request *rq;
    struct parport *pp;
    struct parport_uss720_private *priv;
    int status = urb->status;

    rq = urb->context;
    priv = rq->priv;
    pp = priv->pp;
    if (status) {
        dev_err(&urb->dev->dev, "async_complete: urb error %d\n",
            status);
    } else if (rq->dr.bRequest == 3) {
        memcpy(priv->reg, rq->reg, sizeof(priv->reg));
#if 0
        dev_dbg(&priv->usbdev->dev,
            "async_complete regs %02x %02x %02x %02x %02x %02x %02x\n",
            (unsigned int)priv->reg[0], (unsigned int)priv->reg[1],
            (unsigned int)priv->reg[2], (unsigned int)priv->reg[3],
            (unsigned int)priv->reg[4], (unsigned int)priv->reg[5],
            (unsigned int)priv->reg[6]);
#endif
        /* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
        if (rq->reg[2] & rq->reg[1] & 0x10 && pp)
            parport_generic_irq(pp);
    }
    complete(&rq->compl);
    kref_put(&rq->ref_count, destroy_async);
}

static struct uss720_async_request *submit_async_request(struct parport_uss720_private *priv,
                             __u8 request, __u8 requesttype, __u16 value, __u16 index,
                             gfp_t mem_flags)
{
    struct usb_device *usbdev;
    struct uss720_async_request *rq;
    unsigned long flags;
    int ret;

    if (!priv)
        return NULL;
    usbdev = priv->usbdev;
    if (!usbdev)
        return NULL;
    rq = kmalloc(sizeof(struct uss720_async_request), mem_flags);
    if (!rq) {
        dev_err(&usbdev->dev, "submit_async_request out of memory\n");
        return NULL;
    }
    kref_init(&rq->ref_count);
    INIT_LIST_HEAD(&rq->asynclist);
    init_completion(&rq->compl);
    kref_get(&priv->ref_count);
    rq->priv = priv;
    rq->urb = usb_alloc_urb(0, mem_flags);
    if (!rq->urb) {
        kref_put(&rq->ref_count, destroy_async);
        dev_err(&usbdev->dev, "submit_async_request out of memory\n");
        return NULL;
    }
    rq->dr.bRequestType = requesttype;
    rq->dr.bRequest = request;
    rq->dr.wValue = cpu_to_le16(value);
    rq->dr.wIndex = cpu_to_le16(index);
    rq->dr.wLength = cpu_to_le16((request == 3) ? sizeof(rq->reg) : 0);
    usb_fill_control_urb(rq->urb, usbdev, (requesttype & 0x80) ? usb_rcvctrlpipe(usbdev, 0) : usb_sndctrlpipe(usbdev, 0),
                 (unsigned char *)&rq->dr,
                 (request == 3) ? rq->reg : NULL, (request == 3) ? sizeof(rq->reg) : 0, async_complete, rq);
    /* rq->urb->transfer_flags |= URB_ASYNC_UNLINK; */
    spin_lock_irqsave(&priv->asynclock, flags);
    list_add_tail(&rq->asynclist, &priv->asynclist);
    spin_unlock_irqrestore(&priv->asynclock, flags);
    kref_get(&rq->ref_count);
    ret = usb_submit_urb(rq->urb, mem_flags);
    if (!ret)
        return rq;
    destroy_async(&rq->ref_count);
    dev_err(&usbdev->dev, "submit_async_request submit_urb failed with %d\n", ret);
    return NULL;
}

static unsigned int kill_all_async_requests_priv(struct parport_uss720_private *priv)
{
    struct uss720_async_request *rq;
    unsigned long flags;
    unsigned int ret = 0;

    spin_lock_irqsave(&priv->asynclock, flags);
    list_for_each_entry(rq, &priv->asynclist, asynclist) {
        usb_unlink_urb(rq->urb);
        ret++;
    }
    spin_unlock_irqrestore(&priv->asynclock, flags);
    return ret;
}

/* --------------------------------------------------------------------- */

static int get_1284_register(struct parport *pp, unsigned char reg, unsigned char *val, gfp_t mem_flags)
{
    struct parport_uss720_private *priv;
    struct uss720_async_request *rq;
    static const unsigned char regindex[9] = {
        4, 0, 1, 5, 5, 0, 2, 3, 6
    };
    int ret;

    if (!pp)
        return -EIO;
    priv = pp->private_data;
    rq = submit_async_request(priv, 3, 0xc0, ((unsigned int)reg) << 8, 0, mem_flags);
    if (!rq) {
        dev_err(&priv->usbdev->dev, "get_1284_register(%u) failed",
            (unsigned int)reg);
        return -EIO;
    }
    if (!val) {
        kref_put(&rq->ref_count, destroy_async);
        return 0;
    }
    if (wait_for_completion_timeout(&rq->compl, HZ)) {
        ret = rq->urb->status;
        *val = priv->reg[(reg >= 9) ? 0 : regindex[reg]];
        if (ret)
            printk(KERN_WARNING "get_1284_register: "
                   "usb error %d\n", ret);
        kref_put(&rq->ref_count, destroy_async);
        return ret;
    }
    printk(KERN_WARNING "get_1284_register timeout\n");
    kill_all_async_requests_priv(priv);
    return -EIO;
}

static int set_1284_register(struct parport *pp, unsigned char reg, unsigned char val, gfp_t mem_flags)
{
    struct parport_uss720_private *priv;
    struct uss720_async_request *rq;

    if (!pp)
        return -EIO;
    priv = pp->private_data;
    rq = submit_async_request(priv, 4, 0x40, (((unsigned int)reg) << 8) | val, 0, mem_flags);
    if (!rq) {
        dev_err(&priv->usbdev->dev, "set_1284_register(%u,%u) failed",
            (unsigned int)reg, (unsigned int)val);
        return -EIO;
    }
    kref_put(&rq->ref_count, destroy_async);
    return 0;
}

/* --------------------------------------------------------------------- */

/* ECR modes */
#define ECR_SPP 00
#define ECR_PS2 01
#define ECR_PPF 02
#define ECR_ECP 03
#define ECR_EPP 04

/* Safely change the mode bits in the ECR */
static int change_mode(struct parport *pp, int m)
{
    struct parport_uss720_private *priv = pp->private_data;
    int mode;
    __u8 reg;

    if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
        return -EIO;
    /* Bits <7:5> contain the mode. */
    mode = (priv->reg[2] >> 5) & 0x7;
    if (mode == m)
        return 0;
    /* We have to go through mode 000 or 001 */
    if (mode > ECR_PS2 && m > ECR_PS2)
        if (change_mode(pp, ECR_PS2))
            return -EIO;

    if (m <= ECR_PS2 && !(priv->reg[1] & 0x20)) {
        /* This mode resets the FIFO, so we may
         * have to wait for it to drain first. */
        unsigned long expire = jiffies + pp->physport->cad->timeout;
        switch (mode) {
        case ECR_PPF: /* Parallel Port FIFO mode */
        case ECR_ECP: /* ECP Parallel Port mode */
            /* Poll slowly. */
            for (;;) {
                if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
                    return -EIO;
                if (priv->reg[2] & 0x01)
                    break;
                if (time_after_eq (jiffies, expire))
                    /* The FIFO is stuck. */
                    return -EBUSY;
                msleep_interruptible(10);
                if (signal_pending (current))
                    break;
            }
        }
    }
    /* Set the mode. */
    if (set_1284_register(pp, 6, m << 5, GFP_KERNEL))
        return -EIO;
    if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
        return -EIO;
    return 0;
}

/*
 * Clear TIMEOUT BIT in EPP MODE
 */
static int clear_epp_timeout(struct parport *pp)
{
    unsigned char stat;

    if (get_1284_register(pp, 1, &stat, GFP_KERNEL))
        return 1;
    return stat & 1;
}

/*
 * Access functions.
 */
#if 0
static int uss720_irq(int usbstatus, void *buffer, int len, void *dev_id)
{
    struct parport *pp = (struct parport *)dev_id;
    struct parport_uss720_private *priv = pp->private_data; 

    if (usbstatus != 0 || len < 4 || !buffer)
        return 1;
    memcpy(priv->reg, buffer, 4);
    /* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
    if (priv->reg[2] & priv->reg[1] & 0x10)
        parport_generic_irq(pp);
    return 1;
}
#endif

static void parport_uss720_write_data(struct parport *pp, unsigned char d)
{
    set_1284_register(pp, 0, d, GFP_KERNEL);
}

static unsigned char parport_uss720_read_data(struct parport *pp)
{
    unsigned char ret;

    if (get_1284_register(pp, 0, &ret, GFP_KERNEL))
        return 0;
    return ret;
}

static void parport_uss720_write_control(struct parport *pp, unsigned char d)
{
    struct parport_uss720_private *priv = pp->private_data; 

    d = (d & 0xf) | (priv->reg[1] & 0xf0);
    if (set_1284_register(pp, 2, d, GFP_KERNEL))
        return;
    priv->reg[1] = d;
}

static unsigned char parport_uss720_read_control(struct parport *pp)
{
    struct parport_uss720_private *priv = pp->private_data; 
    return priv->reg[1] & 0xf; /* Use soft copy */
}

static unsigned char parport_uss720_frob_control(struct parport *pp, unsigned char mask, unsigned char val)
{
    struct parport_uss720_private *priv = pp->private_data; 
    unsigned char d;

    mask &= 0x0f;
    val &= 0x0f;
    d = (priv->reg[1] & (~mask)) ^ val;
    if (set_1284_register(pp, 2, d, GFP_KERNEL))
        return 0;
    priv->reg[1] = d;
    return d & 0xf;
}

static unsigned char parport_uss720_read_status(struct parport *pp)
{
    unsigned char ret;

    if (get_1284_register(pp, 1, &ret, GFP_KERNEL))
        return 0;
    return ret & 0xf8;
}

static void parport_uss720_disable_irq(struct parport *pp)
{
    struct parport_uss720_private *priv = pp->private_data; 
    unsigned char d;

    d = priv->reg[1] & ~0x10;
    if (set_1284_register(pp, 2, d, GFP_KERNEL))
        return;
    priv->reg[1] = d;
}

static void parport_uss720_enable_irq(struct parport *pp)
{
    struct parport_uss720_private *priv = pp->private_data; 
    unsigned char d;

    d = priv->reg[1] | 0x10;
    if (set_1284_register(pp, 2, d, GFP_KERNEL))
        return;
    priv->reg[1] = d;
}

static void parport_uss720_data_forward (struct parport *pp)
{
    struct parport_uss720_private *priv = pp->private_data; 
    unsigned char d;

    d = priv->reg[1] & ~0x20;
    if (set_1284_register(pp, 2, d, GFP_KERNEL))
        return;
    priv->reg[1] = d;
}

static void parport_uss720_data_reverse (struct parport *pp)
{
    struct parport_uss720_private *priv = pp->private_data; 
    unsigned char d;

    d = priv->reg[1] | 0x20;
    if (set_1284_register(pp, 2, d, GFP_KERNEL))
        return;
    priv->reg[1] = d;
}

static void parport_uss720_init_state(struct pardevice *dev, struct parport_state *s)
{
    s->u.pc.ctr = 0xc | (dev->irq_func ? 0x10 : 0x0);
    s->u.pc.ecr = 0x24;
}

static void parport_uss720_save_state(struct parport *pp, struct parport_state *s)
{
    struct parport_uss720_private *priv = pp->private_data; 

#if 0
    if (get_1284_register(pp, 2, NULL, GFP_ATOMIC))
        return;
#endif
    s->u.pc.ctr = priv->reg[1];
    s->u.pc.ecr = priv->reg[2];
}

static void parport_uss720_restore_state(struct parport *pp, struct parport_state *s)
{
    struct parport_uss720_private *priv = pp->private_data;

    set_1284_register(pp, 2, s->u.pc.ctr, GFP_ATOMIC);
    set_1284_register(pp, 6, s->u.pc.ecr, GFP_ATOMIC);
    get_1284_register(pp, 2, NULL, GFP_ATOMIC);
    priv->reg[1] = s->u.pc.ctr;
    priv->reg[2] = s->u.pc.ecr;
}

static size_t parport_uss720_epp_read_data(struct parport *pp, void *buf, size_t length, int flags)
{
    struct parport_uss720_private *priv = pp->private_data; 
    size_t got = 0;

    if (change_mode(pp, ECR_EPP))
        return 0;
    for (; got < length; got++) {
        if (get_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
            break;
        buf++;
        if (priv->reg[0] & 0x01) {
            clear_epp_timeout(pp);
            break;
        }
    }
    change_mode(pp, ECR_PS2);
    return got;
}

static size_t parport_uss720_epp_write_data(struct parport *pp, const void *buf, size_t length, int flags)
{
#if 0
    struct parport_uss720_private *priv = pp->private_data; 
    size_t written = 0;

    if (change_mode(pp, ECR_EPP))
        return 0;
    for (; written < length; written++) {
        if (set_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
            break;
        ((char*)buf)++;
        if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
            break;
        if (priv->reg[0] & 0x01) {
            clear_epp_timeout(pp);
            break;
        }
    }
    change_mode(pp, ECR_PS2);
    return written;
#else
    struct parport_uss720_private *priv = pp->private_data;
    struct usb_device *usbdev = priv->usbdev;
    int rlen;
    int i;

    if (!usbdev)
        return 0;
    if (change_mode(pp, ECR_EPP))
        return 0;
    i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buf, length, &rlen, 20000);
    if (i)
        printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %Zu rlen %u\n", buf, length, rlen);
    change_mode(pp, ECR_PS2);
    return rlen;
#endif
}

static size_t parport_uss720_epp_read_addr(struct parport *pp, void *buf, size_t length, int flags)
{
    struct parport_uss720_private *priv = pp->private_data; 
    size_t got = 0;

    if (change_mode(pp, ECR_EPP))
        return 0;
    for (; got < length; got++) {
        if (get_1284_register(pp, 3, (char *)buf, GFP_KERNEL))
            break;
        buf++;
        if (priv->reg[0] & 0x01) {
            clear_epp_timeout(pp);
            break;
        }
    }
    change_mode(pp, ECR_PS2);
    return got;
}

static size_t parport_uss720_epp_write_addr(struct parport *pp, const void *buf, size_t length, int flags)
{
    struct parport_uss720_private *priv = pp->private_data; 
    size_t written = 0;

    if (change_mode(pp, ECR_EPP))
        return 0;
    for (; written < length; written++) {
        if (set_1284_register(pp, 3, *(char *)buf, GFP_KERNEL))
            break;
        buf++;
        if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
            break;
        if (priv->reg[0] & 0x01) {
            clear_epp_timeout(pp);
            break;
        }
    }
    change_mode(pp, ECR_PS2);
    return written;
}

static size_t parport_uss720_ecp_write_data(struct parport *pp, const void *buffer, size_t len, int flags)
{
    struct parport_uss720_private *priv = pp->private_data;
    struct usb_device *usbdev = priv->usbdev;
    int rlen;
    int i;

    if (!usbdev)
        return 0;
    if (change_mode(pp, ECR_ECP))
        return 0;
    i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buffer, len, &rlen, 20000);
    if (i)
        printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %Zu rlen %u\n", buffer, len, rlen);
    change_mode(pp, ECR_PS2);
    return rlen;
}

static size_t parport_uss720_ecp_read_data(struct parport *pp, void *buffer, size_t len, int flags)
{
    struct parport_uss720_private *priv = pp->private_data;
    struct usb_device *usbdev = priv->usbdev;
    int rlen;
    int i;

    if (!usbdev)
        return 0;
    if (change_mode(pp, ECR_ECP))
        return 0;
    i = usb_bulk_msg(usbdev, usb_rcvbulkpipe(usbdev, 2), buffer, len, &rlen, 20000);
    if (i)
        printk(KERN_ERR "uss720: recvbulk ep 2 buf %p len %Zu rlen %u\n", buffer, len, rlen);
    change_mode(pp, ECR_PS2);
    return rlen;
}

static size_t parport_uss720_ecp_write_addr(struct parport *pp, const void *buffer, size_t len, int flags)
{
    size_t written = 0;

    if (change_mode(pp, ECR_ECP))
        return 0;
    for (; written < len; written++) {
        if (set_1284_register(pp, 5, *(char *)buffer, GFP_KERNEL))
            break;
        buffer++;
    }
    change_mode(pp, ECR_PS2);
    return written;
}

static size_t parport_uss720_write_compat(struct parport *pp, const void *buffer, size_t len, int flags)
{
    struct parport_uss720_private *priv = pp->private_data;
    struct usb_device *usbdev = priv->usbdev;
    int rlen;
    int i;

    if (!usbdev)
        return 0;
    if (change_mode(pp, ECR_PPF))
        return 0;
    i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buffer, len, &rlen, 20000);
    if (i)
        printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %Zu rlen %u\n", buffer, len, rlen);
    change_mode(pp, ECR_PS2);
    return rlen;
}

/* --------------------------------------------------------------------- */

static struct parport_operations parport_uss720_ops = 
{
    .owner =        THIS_MODULE,
    .write_data =       parport_uss720_write_data,
    .read_data =        parport_uss720_read_data,

    .write_control =    parport_uss720_write_control,
    .read_control =     parport_uss720_read_control,
    .frob_control =     parport_uss720_frob_control,

    .read_status =      parport_uss720_read_status,

    .enable_irq =       parport_uss720_enable_irq,
    .disable_irq =      parport_uss720_disable_irq,

    .data_forward =     parport_uss720_data_forward,
    .data_reverse =     parport_uss720_data_reverse,

    .init_state =       parport_uss720_init_state,
    .save_state =       parport_uss720_save_state,
    .restore_state =    parport_uss720_restore_state,

    .epp_write_data =   parport_uss720_epp_write_data,
    .epp_read_data =    parport_uss720_epp_read_data,
    .epp_write_addr =   parport_uss720_epp_write_addr,
    .epp_read_addr =    parport_uss720_epp_read_addr,

    .ecp_write_data =   parport_uss720_ecp_write_data,
    .ecp_read_data =    parport_uss720_ecp_read_data,
    .ecp_write_addr =   parport_uss720_ecp_write_addr,

    .compat_write_data =    parport_uss720_write_compat,
    .nibble_read_data = parport_ieee1284_read_nibble,
    .byte_read_data =   parport_ieee1284_read_byte,
};

/* --------------------------------------------------------------------- */

static int uss720_probe(struct usb_interface *intf,
            const struct usb_device_id *id)
{
    struct usb_device *usbdev = usb_get_dev(interface_to_usbdev(intf));
    struct usb_host_interface *interface;
    struct usb_host_endpoint *endpoint;
    struct parport_uss720_private *priv;
    struct parport *pp;
    unsigned char reg;
    int i;

    dev_dbg(&intf->dev, "probe: vendor id 0x%x, device id 0x%x\n",
        le16_to_cpu(usbdev->descriptor.idVendor),
        le16_to_cpu(usbdev->descriptor.idProduct));

    /* our known interfaces have 3 alternate settings */
    if (intf->num_altsetting != 3) {
        usb_put_dev(usbdev);
        return -ENODEV;
    }
    i = usb_set_interface(usbdev, intf->altsetting->desc.bInterfaceNumber, 2);
    dev_dbg(&intf->dev, "set inteface result %d\n", i);

    interface = intf->cur_altsetting;

    /*
     * Allocate parport interface 
     */
    if (!(priv = kzalloc(sizeof(struct parport_uss720_private), GFP_KERNEL))) {
        usb_put_dev(usbdev);
        return -ENOMEM;
    }
    priv->pp = NULL;
    priv->usbdev = usbdev;
    kref_init(&priv->ref_count);
    spin_lock_init(&priv->asynclock);
    INIT_LIST_HEAD(&priv->asynclist);
    if (!(pp = parport_register_port(0, PARPORT_IRQ_NONE, PARPORT_DMA_NONE, &parport_uss720_ops))) {
        printk(KERN_WARNING "uss720: could not register parport\n");
        goto probe_abort;
    }

    priv->pp = pp;
    pp->private_data = priv;
    pp->modes = PARPORT_MODE_PCSPP | PARPORT_MODE_TRISTATE | PARPORT_MODE_EPP | PARPORT_MODE_ECP | PARPORT_MODE_COMPAT;

    /* set the USS720 control register to manual mode, no ECP compression, enable all ints */
    set_1284_register(pp, 7, 0x00, GFP_KERNEL);
    set_1284_register(pp, 6, 0x30, GFP_KERNEL);  /* PS/2 mode */
    set_1284_register(pp, 2, 0x0c, GFP_KERNEL);
    /* debugging */
    get_1284_register(pp, 0, &reg, GFP_KERNEL);
    dev_dbg(&intf->dev, "reg: %02x %02x %02x %02x %02x %02x %02x\n",
        priv->reg[0], priv->reg[1], priv->reg[2], priv->reg[3],
        priv->reg[4], priv->reg[5], priv->reg[6]);

    endpoint = &interface->endpoint[2];
    dev_dbg(&intf->dev, "epaddr %d interval %d\n",
        endpoint->desc.bEndpointAddress, endpoint->desc.bInterval);
    parport_announce_port(pp);

    usb_set_intfdata(intf, pp);
    return 0;

probe_abort:
    kill_all_async_requests_priv(priv);
    kref_put(&priv->ref_count, destroy_priv);
    return -ENODEV;
}

static void uss720_disconnect(struct usb_interface *intf)
{
    struct parport *pp = usb_get_intfdata(intf);
    struct parport_uss720_private *priv;
    struct usb_device *usbdev;

    dev_dbg(&intf->dev, "disconnect\n");
    usb_set_intfdata(intf, NULL);
    if (pp) {
        priv = pp->private_data;
        usbdev = priv->usbdev;
        priv->usbdev = NULL;
        priv->pp = NULL;
        dev_dbg(&intf->dev, "parport_remove_port\n");
        parport_remove_port(pp);
        parport_put_port(pp);
        kill_all_async_requests_priv(priv);
        kref_put(&priv->ref_count, destroy_priv);
    }
    dev_dbg(&intf->dev, "disconnect done\n");
}

/* table of cables that work through this driver */
static const struct usb_device_id uss720_table[] = {
    { USB_DEVICE(0x047e, 0x1001) },
    { USB_DEVICE(0x0557, 0x2001) },
    { USB_DEVICE(0x0729, 0x1284) },
    { USB_DEVICE(0x1293, 0x0002) },
    { USB_DEVICE(0x050d, 0x0002) },
    { }                     /* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, uss720_table);


static struct usb_driver uss720_driver = {
    .name =     "uss720",
    .probe =    uss720_probe,
    .disconnect =   uss720_disconnect,
    .id_table = uss720_table,
};

/* --------------------------------------------------------------------- */

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

static int __init uss720_init(void)
{
    int retval;
    retval = usb_register(&uss720_driver);
    if (retval)
        goto out;

    printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
           DRIVER_DESC "\n");
    printk(KERN_INFO KBUILD_MODNAME ": NOTE: this is a special purpose "
           "driver to allow nonstandard\n");
    printk(KERN_INFO KBUILD_MODNAME ": protocols (eg. bitbang) over "
           "USS720 usb to parallel cables\n");
    printk(KERN_INFO KBUILD_MODNAME ": If you just want to connect to a "
           "printer, use usblp instead\n");
out:
    return retval;
}

static void __exit uss720_cleanup(void)
{
    usb_deregister(&uss720_driver);
}

module_init(uss720_init);
module_exit(uss720_cleanup);

/* --------------------------------------------------------------------- */