Quelle ppdev.c Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* linux/drivers/char/ppdev.c
*
* This is the code behind /dev/parport* -- it allows a user-space
* application to use the parport subsystem.
*
* Copyright (C) 1998-2000, 2002 Tim Waugh <tim@cyberelk.net>
*
* A /dev/parportx device node represents an arbitrary device
* on port 'x'.  The following operations are possible:
*
* open do nothing, set up default IEEE 1284 protocol to be COMPAT
* close release port and unregister device (if necessary)
* ioctl
*   EXCL register device exclusively (may fail)
*   CLAIM (register device first time) parport_claim_or_block
*   RELEASE parport_release
*   SETMODE set the IEEE 1284 protocol to use for read/write
*   SETPHASE set the IEEE 1284 phase of a particular mode.  Not to be
*              confused with ioctl(fd, SETPHASER, &stun). ;-)
*   DATADIR data_forward / data_reverse
*   WDATA write_data
*   RDATA read_data
*   WCONTROL write_control
*   RCONTROL read_control
*   FCONTROL frob_control
*   RSTATUS read_status
*   NEGOT parport_negotiate
*   YIELD parport_yield_blocking
*   WCTLONIRQ on interrupt, set control lines
*   CLRIRQ clear (and return) interrupt count
*   SETTIME sets device timeout (struct timeval)
*   GETTIME gets device timeout (struct timeval)
*   GETMODES gets hardware supported modes (unsigned int)
*   GETMODE gets the current IEEE1284 mode
*   GETPHASE   gets the current IEEE1284 phase
*   GETFLAGS   gets current (user-visible) flags
*   SETFLAGS   sets current (user-visible) flags
* read/write read or write in current IEEE 1284 protocol
* select wait for interrupt (in readfds)
*
* Changes:
* Added SETTIME/GETTIME ioctl, Fred Barnes, 1999.
*
* Arnaldo Carvalho de Melo <acme@conectiva.com.br> 2000/08/25
* - On error, copy_from_user and copy_to_user do not return -EFAULT,
*   They return the positive number of bytes *not* copied due to address
*   space errors.
*
* Added GETMODES/GETMODE/GETPHASE ioctls, Fred Barnes <frmb2@ukc.ac.uk>, 03/01/2001.
* Added GETFLAGS/SETFLAGS ioctls, Fred Barnes, 04/2001
*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched/signal.h>
#include <linux/device.h>
#include <linux/ioctl.h>
#include <linux/parport.h>
#include <linux/ctype.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/major.h>
#include <linux/ppdev.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <linux/compat.h>

#define PP_VERSION "ppdev: user-space parallel port driver"
#define CHRDEV "ppdev"

struct pp_struct {
struct pardevice *pdev;
wait_queue_head_t irq_wait;
atomic_t irqc;
unsigned int flags;
int irqresponse;
unsigned char irqctl;
struct ieee1284_info state;
struct ieee1284_info saved_state;
long default_inactivity;
int index;
};

/* should we use PARDEVICE_MAX here? */
static struct device *devices[PARPORT_MAX];

static DEFINE_IDA(ida_index);

/* pp_struct.flags bitfields */
#define PP_CLAIMED    (1<<0)
#define PP_EXCL       (1<<1)

/* Other constants */
#define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
#define PP_BUFFER_SIZE 1024
#define PARDEVICE_MAX 8

static DEFINE_MUTEX(pp_do_mutex);

/* define fixed sized ioctl cmd for y2038 migration */
#define PPGETTIME32 _IOR(PP_IOCTL, 0x95, s32[2])
#define PPSETTIME32 _IOW(PP_IOCTL, 0x96, s32[2])
#define PPGETTIME64 _IOR(PP_IOCTL, 0x95, s64[2])
#define PPSETTIME64 _IOW(PP_IOCTL, 0x96, s64[2])

static inline void pp_enable_irq(struct pp_struct *pp)
{
struct parport *port = pp->pdev->port;

port->ops->enable_irq(port);
}

static ssize_t pp_read(struct file *file, char __user *buf, size_t count,
         loff_t *ppos)
{
unsigned int minor = iminor(file_inode(file));
struct pp_struct *pp = file->private_data;
char *kbuffer;
ssize_t bytes_read = 0;
struct parport *pport;
int mode;

if (!(pp->flags & PP_CLAIMED)) {
  /* Don't have the port claimed */
  pr_debug(CHRDEV "%x: claim the port first\n", minor);
  return -EINVAL;
}

/* Trivial case. */
if (count == 0)
  return 0;

kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
if (!kbuffer)
  return -ENOMEM;
pport = pp->pdev->port;
mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);

parport_set_timeout(pp->pdev,
       (file->f_flags & O_NONBLOCK) ?
       PARPORT_INACTIVITY_O_NONBLOCK :
       pp->default_inactivity);

while (bytes_read == 0) {
  ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);

  if (mode == IEEE1284_MODE_EPP) {
   /* various specials for EPP mode */
   int flags = 0;
   size_t (*fn)(struct parport *, void *, size_t, int);

   if (pp->flags & PP_W91284PIC)
    flags |= PARPORT_W91284PIC;
   if (pp->flags & PP_FASTREAD)
    flags |= PARPORT_EPP_FAST;
   if (pport->ieee1284.mode & IEEE1284_ADDR)
    fn = pport->ops->epp_read_addr;
   else
    fn = pport->ops->epp_read_data;
   bytes_read = (*fn)(pport, kbuffer, need, flags);
  } else {
   bytes_read = parport_read(pport, kbuffer, need);
  }

  if (bytes_read != 0)
   break;

  if (file->f_flags & O_NONBLOCK) {
   bytes_read = -EAGAIN;
   break;
  }

  if (signal_pending(current)) {
   bytes_read = -ERESTARTSYS;
   break;
  }

  cond_resched();
}

parport_set_timeout(pp->pdev, pp->default_inactivity);

if (bytes_read > 0 && copy_to_user(buf, kbuffer, bytes_read))
  bytes_read = -EFAULT;

kfree(kbuffer);
pp_enable_irq(pp);
return bytes_read;
}

static ssize_t pp_write(struct file *file, const char __user *buf,
   size_t count, loff_t *ppos)
{
unsigned int minor = iminor(file_inode(file));
struct pp_struct *pp = file->private_data;
char *kbuffer;
ssize_t bytes_written = 0;
ssize_t wrote;
int mode;
struct parport *pport;

if (!(pp->flags & PP_CLAIMED)) {
  /* Don't have the port claimed */
  pr_debug(CHRDEV "%x: claim the port first\n", minor);
  return -EINVAL;
}

kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
if (!kbuffer)
  return -ENOMEM;

pport = pp->pdev->port;
mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);

parport_set_timeout(pp->pdev,
       (file->f_flags & O_NONBLOCK) ?
       PARPORT_INACTIVITY_O_NONBLOCK :
       pp->default_inactivity);

while (bytes_written < count) {
  ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);

  if (copy_from_user(kbuffer, buf + bytes_written, n)) {
   bytes_written = -EFAULT;
   break;
  }

  if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
   /* do a fast EPP write */
   if (pport->ieee1284.mode & IEEE1284_ADDR) {
    wrote = pport->ops->epp_write_addr(pport,
     kbuffer, n, PARPORT_EPP_FAST);
   } else {
    wrote = pport->ops->epp_write_data(pport,
     kbuffer, n, PARPORT_EPP_FAST);
   }
  } else {
   wrote = parport_write(pp->pdev->port, kbuffer, n);
  }

  if (wrote <= 0) {
   if (!bytes_written)
    bytes_written = wrote;
   break;
  }

  bytes_written += wrote;

  if (file->f_flags & O_NONBLOCK) {
   if (!bytes_written)
    bytes_written = -EAGAIN;
   break;
  }

  if (signal_pending(current))
   break;

  cond_resched();
}

parport_set_timeout(pp->pdev, pp->default_inactivity);

kfree(kbuffer);
pp_enable_irq(pp);
return bytes_written;
}

static void pp_irq(void *private)
{
struct pp_struct *pp = private;

if (pp->irqresponse) {
  parport_write_control(pp->pdev->port, pp->irqctl);
  pp->irqresponse = 0;
}

atomic_inc(&pp->irqc);
wake_up_interruptible(&pp->irq_wait);
}

static int register_device(int minor, struct pp_struct *pp)
{
struct parport *port;
struct pardevice *pdev = NULL;
char *name;
struct pardev_cb ppdev_cb;
int rc = 0, index;

name = kasprintf(GFP_KERNEL, CHRDEV "%x", minor);
if (name == NULL)
  return -ENOMEM;

port = parport_find_number(minor);
if (!port) {
  pr_warn("%s: no associated port!\n", name);
  rc = -ENXIO;
  goto err_free_name;
}

index = ida_alloc(&ida_index, GFP_KERNEL);
if (index < 0) {
  pr_warn("%s: failed to get index!\n", name);
  rc = index;
  goto err_put_port;
}

memset(&ppdev_cb, 0, sizeof(ppdev_cb));
ppdev_cb.irq_func = pp_irq;
ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
ppdev_cb.private = pp;
pdev = parport_register_dev_model(port, name, &ppdev_cb, index);

if (!pdev) {
  pr_warn("%s: failed to register device!\n", name);
  rc = -ENXIO;
  ida_free(&ida_index, index);
  goto err_put_port;
}

pp->pdev = pdev;
pp->index = index;
dev_dbg(&pdev->dev, "registered pardevice\n");
err_put_port:
parport_put_port(port);
err_free_name:
kfree(name);
return rc;
}

static enum ieee1284_phase init_phase(int mode)
{
switch (mode & ~(IEEE1284_DEVICEID
    | IEEE1284_ADDR)) {
case IEEE1284_MODE_NIBBLE:
case IEEE1284_MODE_BYTE:
  return IEEE1284_PH_REV_IDLE;
}
return IEEE1284_PH_FWD_IDLE;
}

static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
{
long to_jiffies;

if ((tv_sec < 0) || (tv_usec < 0))
  return -EINVAL;

to_jiffies = usecs_to_jiffies(tv_usec);
to_jiffies += tv_sec * HZ;
if (to_jiffies <= 0)
  return -EINVAL;

pdev->timeout = to_jiffies;
return 0;
}

static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
unsigned int minor = iminor(file_inode(file));
struct pp_struct *pp = file->private_data;
struct parport *port;
void __user *argp = (void __user *)arg;
struct ieee1284_info *info;
unsigned char reg;
unsigned char mask;
int mode;
s32 time32[2];
s64 time64[2];
struct timespec64 ts;
int ret;

/* First handle the cases that don't take arguments. */
switch (cmd) {
case PPCLAIM:
     {
  if (pp->flags & PP_CLAIMED) {
   dev_dbg(&pp->pdev->dev, "you've already got it!\n");
   return -EINVAL;
  }

  /* Deferred device registration. */
  if (!pp->pdev) {
   int err = register_device(minor, pp);

   if (err)
    return err;
  }

  ret = parport_claim_or_block(pp->pdev);
  if (ret < 0)
   return ret;

  pp->flags |= PP_CLAIMED;

  /* For interrupt-reporting to work, we need to be
* informed of each interrupt. */
  pp_enable_irq(pp);

  /* We may need to fix up the state machine. */
  info = &pp->pdev->port->ieee1284;
  pp->saved_state.mode = info->mode;
  pp->saved_state.phase = info->phase;
  info->mode = pp->state.mode;
  info->phase = pp->state.phase;
  pp->default_inactivity = parport_set_timeout(pp->pdev, 0);
  parport_set_timeout(pp->pdev, pp->default_inactivity);

  return 0;
     }
case PPEXCL:
  if (pp->pdev) {
   dev_dbg(&pp->pdev->dev,
    "too late for PPEXCL; already registered\n");
   if (pp->flags & PP_EXCL)
    /* But it's not really an error. */
    return 0;
   /* There's no chance of making the driver happy. */
   return -EINVAL;
  }

  /* Just remember to register the device exclusively
* when we finally do the registration. */
  pp->flags |= PP_EXCL;
  return 0;
case PPSETMODE:
     {
  int mode;

  if (copy_from_user(&mode, argp, sizeof(mode)))
   return -EFAULT;
  /* FIXME: validate mode */
  pp->state.mode = mode;
  pp->state.phase = init_phase(mode);

  if (pp->flags & PP_CLAIMED) {
   pp->pdev->port->ieee1284.mode = mode;
   pp->pdev->port->ieee1284.phase = pp->state.phase;
  }

  return 0;
     }
case PPGETMODE:
     {
  int mode;

  if (pp->flags & PP_CLAIMED)
   mode = pp->pdev->port->ieee1284.mode;
  else
   mode = pp->state.mode;

  if (copy_to_user(argp, &mode, sizeof(mode)))
   return -EFAULT;
  return 0;
     }
case PPSETPHASE:
     {
  int phase;

  if (copy_from_user(&phase, argp, sizeof(phase)))
   return -EFAULT;

  /* FIXME: validate phase */
  pp->state.phase = phase;

  if (pp->flags & PP_CLAIMED)
   pp->pdev->port->ieee1284.phase = phase;

  return 0;
     }
case PPGETPHASE:
     {
  int phase;

  if (pp->flags & PP_CLAIMED)
   phase = pp->pdev->port->ieee1284.phase;
  else
   phase = pp->state.phase;
  if (copy_to_user(argp, &phase, sizeof(phase)))
   return -EFAULT;
  return 0;
     }
case PPGETMODES:
     {
  unsigned int modes;

  port = parport_find_number(minor);
  if (!port)
   return -ENODEV;

  modes = port->modes;
  parport_put_port(port);
  if (copy_to_user(argp, &modes, sizeof(modes)))
   return -EFAULT;
  return 0;
     }
case PPSETFLAGS:
     {
  int uflags;

  if (copy_from_user(&uflags, argp, sizeof(uflags)))
   return -EFAULT;
  pp->flags &= ~PP_FLAGMASK;
  pp->flags |= (uflags & PP_FLAGMASK);
  return 0;
     }
case PPGETFLAGS:
     {
  int uflags;

  uflags = pp->flags & PP_FLAGMASK;
  if (copy_to_user(argp, &uflags, sizeof(uflags)))
   return -EFAULT;
  return 0;
     }
} /* end switch() */

/* Everything else requires the port to be claimed, so check
* that now. */
if ((pp->flags & PP_CLAIMED) == 0) {
  pr_debug(CHRDEV "%x: claim the port first\n", minor);
  return -EINVAL;
}

port = pp->pdev->port;
switch (cmd) {
case PPRSTATUS:
  reg = parport_read_status(port);
  if (copy_to_user(argp, ®, sizeof(reg)))
   return -EFAULT;
  return 0;
case PPRDATA:
  reg = parport_read_data(port);
  if (copy_to_user(argp, ®, sizeof(reg)))
   return -EFAULT;
  return 0;
case PPRCONTROL:
  reg = parport_read_control(port);
  if (copy_to_user(argp, ®, sizeof(reg)))
   return -EFAULT;
  return 0;
case PPYIELD:
  parport_yield_blocking(pp->pdev);
  return 0;

case PPRELEASE:
  /* Save the state machine's state. */
  info = &pp->pdev->port->ieee1284;
  pp->state.mode = info->mode;
  pp->state.phase = info->phase;
  info->mode = pp->saved_state.mode;
  info->phase = pp->saved_state.phase;
  parport_release(pp->pdev);
  pp->flags &= ~PP_CLAIMED;
  return 0;

case PPWCONTROL:
  if (copy_from_user(®, argp, sizeof(reg)))
   return -EFAULT;
  parport_write_control(port, reg);
  return 0;

case PPWDATA:
  if (copy_from_user(®, argp, sizeof(reg)))
   return -EFAULT;
  parport_write_data(port, reg);
  return 0;

case PPFCONTROL:
  if (copy_from_user(&mask, argp,
       sizeof(mask)))
   return -EFAULT;
  if (copy_from_user(®, 1 + (unsigned char __user *) arg,
       sizeof(reg)))
   return -EFAULT;
  parport_frob_control(port, mask, reg);
  return 0;

case PPDATADIR:
  if (copy_from_user(&mode, argp, sizeof(mode)))
   return -EFAULT;
  if (mode)
   port->ops->data_reverse(port);
  else
   port->ops->data_forward(port);
  return 0;

case PPNEGOT:
  if (copy_from_user(&mode, argp, sizeof(mode)))
   return -EFAULT;
  switch ((ret = parport_negotiate(port, mode))) {
  case 0: break;
  case -1: /* handshake failed, peripheral not IEEE 1284 */
   ret = -EIO;
   break;
  case 1:  /* handshake succeeded, peripheral rejected mode */
   ret = -ENXIO;
   break;
  }
  pp_enable_irq(pp);
  return ret;

case PPWCTLONIRQ:
  if (copy_from_user(®, argp, sizeof(reg)))
   return -EFAULT;

  /* Remember what to set the control lines to, for next
* time we get an interrupt. */
  pp->irqctl = reg;
  pp->irqresponse = 1;
  return 0;

case PPCLRIRQ:
  ret = atomic_read(&pp->irqc);
  if (copy_to_user(argp, &ret, sizeof(ret)))
   return -EFAULT;
  atomic_sub(ret, &pp->irqc);
  return 0;

case PPSETTIME32:
  if (copy_from_user(time32, argp, sizeof(time32)))
   return -EFAULT;

  if ((time32[0] < 0) || (time32[1] < 0))
   return -EINVAL;

  return pp_set_timeout(pp->pdev, time32[0], time32[1]);

case PPSETTIME64:
  if (copy_from_user(time64, argp, sizeof(time64)))
   return -EFAULT;

  if ((time64[0] < 0) || (time64[1] < 0))
   return -EINVAL;

  if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
   time64[1] >>= 32;

  return pp_set_timeout(pp->pdev, time64[0], time64[1]);

case PPGETTIME32:
  jiffies_to_timespec64(pp->pdev->timeout, &ts);
  time32[0] = ts.tv_sec;
  time32[1] = ts.tv_nsec / NSEC_PER_USEC;

  if (copy_to_user(argp, time32, sizeof(time32)))
   return -EFAULT;

  return 0;

case PPGETTIME64:
  jiffies_to_timespec64(pp->pdev->timeout, &ts);
  time64[0] = ts.tv_sec;
  time64[1] = ts.tv_nsec / NSEC_PER_USEC;

  if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
   time64[1] <<= 32;

  if (copy_to_user(argp, time64, sizeof(time64)))
   return -EFAULT;

  return 0;

default:
  dev_dbg(&pp->pdev->dev, "What? (cmd=0x%x)\n", cmd);
  return -EINVAL;
}

/* Keep the compiler happy */
return 0;
}

static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long ret;

mutex_lock(&pp_do_mutex);
ret = pp_do_ioctl(file, cmd, arg);
mutex_unlock(&pp_do_mutex);
return ret;
}

static int pp_open(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
struct pp_struct *pp;

if (minor >= PARPORT_MAX)
  return -ENXIO;

pp = kmalloc(sizeof(struct pp_struct), GFP_KERNEL);
if (!pp)
  return -ENOMEM;

pp->state.mode = IEEE1284_MODE_COMPAT;
pp->state.phase = init_phase(pp->state.mode);
pp->flags = 0;
pp->irqresponse = 0;
atomic_set(&pp->irqc, 0);
init_waitqueue_head(&pp->irq_wait);

/* Defer the actual device registration until the first claim.
* That way, we know whether or not the driver wants to have
* exclusive access to the port (PPEXCL).
*/
pp->pdev = NULL;
file->private_data = pp;

return 0;
}

static int pp_release(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
struct pp_struct *pp = file->private_data;
int compat_negot;

compat_negot = 0;
if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
     (pp->state.mode != IEEE1284_MODE_COMPAT)) {
  struct ieee1284_info *info;

  /* parport released, but not in compatibility mode */
  parport_claim_or_block(pp->pdev);
  pp->flags |= PP_CLAIMED;
  info = &pp->pdev->port->ieee1284;
  pp->saved_state.mode = info->mode;
  pp->saved_state.phase = info->phase;
  info->mode = pp->state.mode;
  info->phase = pp->state.phase;
  compat_negot = 1;
} else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
     (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
  compat_negot = 2;
}
if (compat_negot) {
  parport_negotiate(pp->pdev->port, IEEE1284_MODE_COMPAT);
  dev_dbg(&pp->pdev->dev,
   "negotiated back to compatibility mode because user-space forgot\n");
}

if ((pp->flags & PP_CLAIMED) && pp->pdev) {
  struct ieee1284_info *info;

  info = &pp->pdev->port->ieee1284;
  pp->state.mode = info->mode;
  pp->state.phase = info->phase;
  info->mode = pp->saved_state.mode;
  info->phase = pp->saved_state.phase;
  parport_release(pp->pdev);
  if (compat_negot != 1) {
   pr_debug(CHRDEV "%x: released pardevice "
    "because user-space forgot\n", minor);
  }
}

if (pp->pdev) {
  parport_unregister_device(pp->pdev);
  ida_free(&ida_index, pp->index);
  pp->pdev = NULL;
  pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
}

kfree(pp);

return 0;
}

/* No kernel lock held - fine */
static __poll_t pp_poll(struct file *file, poll_table *wait)
{
struct pp_struct *pp = file->private_data;
__poll_t mask = 0;

poll_wait(file, &pp->irq_wait, wait);
if (atomic_read(&pp->irqc))
  mask |= EPOLLIN | EPOLLRDNORM;

return mask;
}

static const struct class ppdev_class = {
.name = CHRDEV,
};

static const struct file_operations pp_fops = {
.owner  = THIS_MODULE,
.read  = pp_read,
.write  = pp_write,
.poll  = pp_poll,
.unlocked_ioctl = pp_ioctl,
.compat_ioctl   = compat_ptr_ioctl,
.open  = pp_open,
.release = pp_release,
};

static void pp_attach(struct parport *port)
{
struct device *ret;

if (devices[port->number])
  return;

ret = device_create(&ppdev_class, port->dev,
       MKDEV(PP_MAJOR, port->number), NULL,
       "parport%d", port->number);
if (IS_ERR(ret)) {
  pr_err("Failed to create device parport%d\n",
         port->number);
  return;
}
devices[port->number] = ret;
}

static void pp_detach(struct parport *port)
{
if (!devices[port->number])
  return;

device_destroy(&ppdev_class, MKDEV(PP_MAJOR, port->number));
devices[port->number] = NULL;
}

static int pp_probe(struct pardevice *par_dev)
{
struct device_driver *drv = par_dev->dev.driver;
int len = strlen(drv->name);

if (strncmp(par_dev->name, drv->name, len))
  return -ENODEV;

return 0;
}

static struct parport_driver pp_driver = {
.name  = CHRDEV,
.probe  = pp_probe,
.match_port = pp_attach,
.detach  = pp_detach,
};

static int __init ppdev_init(void)
{
int err = 0;

if (register_chrdev(PP_MAJOR, CHRDEV, &pp_fops)) {
  pr_warn(CHRDEV ": unable to get major %d\n", PP_MAJOR);
  return -EIO;
}
err = class_register(&ppdev_class);
if (err)
  goto out_chrdev;

err = parport_register_driver(&pp_driver);
if (err < 0) {
  pr_warn(CHRDEV ": unable to register with parport\n");
  goto out_class;
}

pr_info(PP_VERSION "\n");
goto out;

out_class:
class_unregister(&ppdev_class);
out_chrdev:
unregister_chrdev(PP_MAJOR, CHRDEV);
out:
return err;
}

static void __exit ppdev_cleanup(void)
{
/* Clean up all parport stuff */
parport_unregister_driver(&pp_driver);
class_unregister(&ppdev_class);
unregister_chrdev(PP_MAJOR, CHRDEV);
}

module_init(ppdev_init);
module_exit(ppdev_cleanup);

MODULE_DESCRIPTION("Support for user-space parallel port device drivers");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);

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