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authorHansjoerg Lipp <hjlipp@web.de>2006-03-26 01:38:32 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-26 08:57:05 -0800
commitee8a4b7f857fe7ba243e65c8925798cf8eda5ab0 (patch)
tree8803a10dd343d13940ebfc34ce633dbacbefcd4e /drivers
parent3c66a22545dd88356bbf4efa45a7b178df8154e9 (diff)
[PATCH] isdn4linux: Siemens Gigaset drivers - tty interface
And: Tilman Schmidt <tilman@imap.cc> This patch adds the tty interface to the gigaset module. The tty interface provides direct access to the AT command set of the Gigaset devices. Signed-off-by: Hansjoerg Lipp <hjlipp@web.de> Signed-off-by: Tilman Schmidt <tilman@imap.cc> Cc: Karsten Keil <kkeil@suse.de> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/isdn/gigaset/interface.c718
1 files changed, 718 insertions, 0 deletions
diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
new file mode 100644
index 000000000000..3a81d9c65141
--- /dev/null
+++ b/drivers/isdn/gigaset/interface.c
@@ -0,0 +1,718 @@
+/*
+ * interface to user space for the gigaset driver
+ *
+ * Copyright (c) 2004 by Hansjoerg Lipp <hjlipp@web.de>
+ *
+ * =====================================================================
+ * 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.
+ * =====================================================================
+ * Version: $Id: interface.c,v 1.14.4.15 2006/02/04 18:28:16 hjlipp Exp $
+ * =====================================================================
+ */
+
+#include "gigaset.h"
+#include <linux/gigaset_dev.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+/*** our ioctls ***/
+
+static int if_lock(struct cardstate *cs, int *arg)
+{
+ int cmd = *arg;
+
+ dbg(DEBUG_IF, "%u: if_lock (%d)", cs->minor_index, cmd);
+
+ if (cmd > 1)
+ return -EINVAL;
+
+ if (cmd < 0) {
+ *arg = atomic_read(&cs->mstate) == MS_LOCKED; //FIXME remove?
+ return 0;
+ }
+
+ if (!cmd && atomic_read(&cs->mstate) == MS_LOCKED
+ && atomic_read(&cs->connected)) {
+ cs->ops->set_modem_ctrl(cs, 0, TIOCM_DTR|TIOCM_RTS);
+ cs->ops->baud_rate(cs, B115200);
+ cs->ops->set_line_ctrl(cs, CS8);
+ cs->control_state = TIOCM_DTR|TIOCM_RTS;
+ }
+
+ cs->waiting = 1;
+ if (!gigaset_add_event(cs, &cs->at_state, EV_IF_LOCK,
+ NULL, cmd, NULL)) {
+ cs->waiting = 0;
+ return -ENOMEM;
+ }
+
+ dbg(DEBUG_CMD, "scheduling IF_LOCK");
+ gigaset_schedule_event(cs);
+
+ wait_event(cs->waitqueue, !cs->waiting);
+
+ if (cs->cmd_result >= 0) {
+ *arg = cs->cmd_result;
+ return 0;
+ }
+
+ return cs->cmd_result;
+}
+
+static int if_version(struct cardstate *cs, unsigned arg[4])
+{
+ static const unsigned version[4] = GIG_VERSION;
+ static const unsigned compat[4] = GIG_COMPAT;
+ unsigned cmd = arg[0];
+
+ dbg(DEBUG_IF, "%u: if_version (%d)", cs->minor_index, cmd);
+
+ switch (cmd) {
+ case GIGVER_DRIVER:
+ memcpy(arg, version, sizeof version);
+ return 0;
+ case GIGVER_COMPAT:
+ memcpy(arg, compat, sizeof compat);
+ return 0;
+ case GIGVER_FWBASE:
+ cs->waiting = 1;
+ if (!gigaset_add_event(cs, &cs->at_state, EV_IF_VER,
+ NULL, 0, arg)) {
+ cs->waiting = 0;
+ return -ENOMEM;
+ }
+
+ dbg(DEBUG_CMD, "scheduling IF_VER");
+ gigaset_schedule_event(cs);
+
+ wait_event(cs->waitqueue, !cs->waiting);
+
+ if (cs->cmd_result >= 0)
+ return 0;
+
+ return cs->cmd_result;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int if_config(struct cardstate *cs, int *arg)
+{
+ dbg(DEBUG_IF, "%u: if_config (%d)", cs->minor_index, *arg);
+
+ if (*arg != 1)
+ return -EINVAL;
+
+ if (atomic_read(&cs->mstate) != MS_LOCKED)
+ return -EBUSY;
+
+ *arg = 0;
+ return gigaset_enterconfigmode(cs);
+}
+
+/*** the terminal driver ***/
+/* stolen from usbserial and some other tty drivers */
+
+static int if_open(struct tty_struct *tty, struct file *filp);
+static void if_close(struct tty_struct *tty, struct file *filp);
+static int if_ioctl(struct tty_struct *tty, struct file *file,
+ unsigned int cmd, unsigned long arg);
+static int if_write_room(struct tty_struct *tty);
+static int if_chars_in_buffer(struct tty_struct *tty);
+static void if_throttle(struct tty_struct *tty);
+static void if_unthrottle(struct tty_struct *tty);
+static void if_set_termios(struct tty_struct *tty, struct termios *old);
+static int if_tiocmget(struct tty_struct *tty, struct file *file);
+static int if_tiocmset(struct tty_struct *tty, struct file *file,
+ unsigned int set, unsigned int clear);
+static int if_write(struct tty_struct *tty,
+ const unsigned char *buf, int count);
+
+static struct tty_operations if_ops = {
+ .open = if_open,
+ .close = if_close,
+ .ioctl = if_ioctl,
+ .write = if_write,
+ .write_room = if_write_room,
+ .chars_in_buffer = if_chars_in_buffer,
+ .set_termios = if_set_termios,
+ .throttle = if_throttle,
+ .unthrottle = if_unthrottle,
+#if 0
+ .break_ctl = serial_break,
+#endif
+ .tiocmget = if_tiocmget,
+ .tiocmset = if_tiocmset,
+};
+
+static int if_open(struct tty_struct *tty, struct file *filp)
+{
+ struct cardstate *cs;
+ unsigned long flags;
+
+ dbg(DEBUG_IF, "%d+%d: %s()", tty->driver->minor_start, tty->index,
+ __FUNCTION__);
+
+ tty->driver_data = NULL;
+
+ cs = gigaset_get_cs_by_tty(tty);
+ if (!cs)
+ return -ENODEV;
+
+ if (down_interruptible(&cs->sem))
+ return -ERESTARTSYS; // FIXME -EINTR?
+ tty->driver_data = cs;
+
+ ++cs->open_count;
+
+ if (cs->open_count == 1) {
+ spin_lock_irqsave(&cs->lock, flags);
+ cs->tty = tty;
+ spin_unlock_irqrestore(&cs->lock, flags);
+ tty->low_latency = 1; //FIXME test
+ //FIXME
+ }
+
+ up(&cs->sem);
+ return 0;
+}
+
+static void if_close(struct tty_struct *tty, struct file *filp)
+{
+ struct cardstate *cs;
+ unsigned long flags;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return;
+ }
+
+ dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __FUNCTION__);
+
+ down(&cs->sem);
+
+ if (!cs->open_count)
+ warn("%s: device not opened", __FUNCTION__);
+ else {
+ if (!--cs->open_count) {
+ spin_lock_irqsave(&cs->lock, flags);
+ cs->tty = NULL;
+ spin_unlock_irqrestore(&cs->lock, flags);
+ //FIXME
+ }
+ }
+
+ up(&cs->sem);
+}
+
+static int if_ioctl(struct tty_struct *tty, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ struct cardstate *cs;
+ int retval = -ENODEV;
+ int int_arg;
+ unsigned char buf[6];
+ unsigned version[4];
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return -ENODEV;
+ }
+
+ dbg(DEBUG_IF, "%u: %s(0x%x)", cs->minor_index, __FUNCTION__, cmd);
+
+ if (down_interruptible(&cs->sem))
+ return -ERESTARTSYS; // FIXME -EINTR?
+
+ if (!cs->open_count)
+ warn("%s: device not opened", __FUNCTION__);
+ else {
+ retval = 0;
+ switch (cmd) {
+ case GIGASET_REDIR:
+ retval = get_user(int_arg, (int __user *) arg);
+ if (retval >= 0)
+ retval = if_lock(cs, &int_arg);
+ if (retval >= 0)
+ retval = put_user(int_arg, (int __user *) arg);
+ break;
+ case GIGASET_CONFIG:
+ retval = get_user(int_arg, (int __user *) arg);
+ if (retval >= 0)
+ retval = if_config(cs, &int_arg);
+ if (retval >= 0)
+ retval = put_user(int_arg, (int __user *) arg);
+ break;
+ case GIGASET_BRKCHARS:
+ //FIXME test if MS_LOCKED
+ gigaset_dbg_buffer(DEBUG_IF, "GIGASET_BRKCHARS",
+ 6, (const unsigned char *) arg, 1);
+ if (!atomic_read(&cs->connected)) {
+ dbg(DEBUG_ANY, "can't communicate with unplugged device");
+ retval = -ENODEV;
+ break;
+ }
+ retval = copy_from_user(&buf,
+ (const unsigned char __user *) arg, 6)
+ ? -EFAULT : 0;
+ if (retval >= 0)
+ retval = cs->ops->brkchars(cs, buf);
+ break;
+ case GIGASET_VERSION:
+ retval = copy_from_user(version, (unsigned __user *) arg,
+ sizeof version) ? -EFAULT : 0;
+ if (retval >= 0)
+ retval = if_version(cs, version);
+ if (retval >= 0)
+ retval = copy_to_user((unsigned __user *) arg, version,
+ sizeof version)
+ ? -EFAULT : 0;
+ break;
+ default:
+ dbg(DEBUG_ANY, "%s: arg not supported - 0x%04x",
+ __FUNCTION__, cmd);
+ retval = -ENOIOCTLCMD;
+ }
+ }
+
+ up(&cs->sem);
+
+ return retval;
+}
+
+static int if_tiocmget(struct tty_struct *tty, struct file *file)
+{
+ struct cardstate *cs;
+ int retval;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return -ENODEV;
+ }
+
+ dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __FUNCTION__);
+
+ if (down_interruptible(&cs->sem))
+ return -ERESTARTSYS; // FIXME -EINTR?
+
+ // FIXME read from device?
+ retval = cs->control_state & (TIOCM_RTS|TIOCM_DTR);
+
+ up(&cs->sem);
+
+ return retval;
+}
+
+static int if_tiocmset(struct tty_struct *tty, struct file *file,
+ unsigned int set, unsigned int clear)
+{
+ struct cardstate *cs;
+ int retval;
+ unsigned mc;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return -ENODEV;
+ }
+
+ dbg(DEBUG_IF,
+ "%u: %s(0x%x, 0x%x)", cs->minor_index, __FUNCTION__, set, clear);
+
+ if (down_interruptible(&cs->sem))
+ return -ERESTARTSYS; // FIXME -EINTR?
+
+ if (!atomic_read(&cs->connected)) {
+ dbg(DEBUG_ANY, "can't communicate with unplugged device");
+ retval = -ENODEV;
+ } else {
+ mc = (cs->control_state | set) & ~clear & (TIOCM_RTS|TIOCM_DTR);
+ retval = cs->ops->set_modem_ctrl(cs, cs->control_state, mc);
+ cs->control_state = mc;
+ }
+
+ up(&cs->sem);
+
+ return retval;
+}
+
+static int if_write(struct tty_struct *tty, const unsigned char *buf, int count)
+{
+ struct cardstate *cs;
+ int retval = -ENODEV;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return -ENODEV;
+ }
+
+ dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __FUNCTION__);
+
+ if (down_interruptible(&cs->sem))
+ return -ERESTARTSYS; // FIXME -EINTR?
+
+ if (!cs->open_count)
+ warn("%s: device not opened", __FUNCTION__);
+ else if (atomic_read(&cs->mstate) != MS_LOCKED) {
+ warn("can't write to unlocked device");
+ retval = -EBUSY;
+ } else if (!atomic_read(&cs->connected)) {
+ dbg(DEBUG_ANY, "can't write to unplugged device");
+ retval = -EBUSY; //FIXME
+ } else {
+ retval = cs->ops->write_cmd(cs, buf, count,
+ &cs->if_wake_tasklet);
+ }
+
+ up(&cs->sem);
+
+ return retval;
+}
+
+static int if_write_room(struct tty_struct *tty)
+{
+ struct cardstate *cs;
+ int retval = -ENODEV;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return -ENODEV;
+ }
+
+ dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __FUNCTION__);
+
+ if (down_interruptible(&cs->sem))
+ return -ERESTARTSYS; // FIXME -EINTR?
+
+ if (!cs->open_count)
+ warn("%s: device not opened", __FUNCTION__);
+ else if (atomic_read(&cs->mstate) != MS_LOCKED) {
+ warn("can't write to unlocked device");
+ retval = -EBUSY; //FIXME
+ } else if (!atomic_read(&cs->connected)) {
+ dbg(DEBUG_ANY, "can't write to unplugged device");
+ retval = -EBUSY; //FIXME
+ } else
+ retval = cs->ops->write_room(cs);
+
+ up(&cs->sem);
+
+ return retval;
+}
+
+static int if_chars_in_buffer(struct tty_struct *tty)
+{
+ struct cardstate *cs;
+ int retval = -ENODEV;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return -ENODEV;
+ }
+
+ dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __FUNCTION__);
+
+ if (down_interruptible(&cs->sem))
+ return -ERESTARTSYS; // FIXME -EINTR?
+
+ if (!cs->open_count)
+ warn("%s: device not opened", __FUNCTION__);
+ else if (atomic_read(&cs->mstate) != MS_LOCKED) {
+ warn("can't write to unlocked device");
+ retval = -EBUSY;
+ } else if (!atomic_read(&cs->connected)) {
+ dbg(DEBUG_ANY, "can't write to unplugged device");
+ retval = -EBUSY; //FIXME
+ } else
+ retval = cs->ops->chars_in_buffer(cs);
+
+ up(&cs->sem);
+
+ return retval;
+}
+
+static void if_throttle(struct tty_struct *tty)
+{
+ struct cardstate *cs;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return;
+ }
+
+ dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __FUNCTION__);
+
+ down(&cs->sem);
+
+ if (!cs->open_count)
+ warn("%s: device not opened", __FUNCTION__);
+ else {
+ //FIXME
+ }
+
+ up(&cs->sem);
+}
+
+static void if_unthrottle(struct tty_struct *tty)
+{
+ struct cardstate *cs;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return;
+ }
+
+ dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __FUNCTION__);
+
+ down(&cs->sem);
+
+ if (!cs->open_count)
+ warn("%s: device not opened", __FUNCTION__);
+ else {
+ //FIXME
+ }
+
+ up(&cs->sem);
+}
+
+static void if_set_termios(struct tty_struct *tty, struct termios *old)
+{
+ struct cardstate *cs;
+ unsigned int iflag;
+ unsigned int cflag;
+ unsigned int old_cflag;
+ unsigned int control_state, new_state;
+
+ cs = (struct cardstate *) tty->driver_data;
+ if (!cs) {
+ err("cs==NULL in %s", __FUNCTION__);
+ return;
+ }
+
+ dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __FUNCTION__);
+
+ down(&cs->sem);
+
+ if (!cs->open_count) {
+ warn("%s: device not opened", __FUNCTION__);
+ goto out;
+ }
+
+ if (!atomic_read(&cs->connected)) {
+ dbg(DEBUG_ANY, "can't communicate with unplugged device");
+ goto out;
+ }
+
+ // stolen from mct_u232.c
+ iflag = tty->termios->c_iflag;
+ cflag = tty->termios->c_cflag;
+ old_cflag = old ? old->c_cflag : cflag; //FIXME?
+ dbg(DEBUG_IF, "%u: iflag %x cflag %x old %x", cs->minor_index,
+ iflag, cflag, old_cflag);
+
+ /* get a local copy of the current port settings */
+ control_state = cs->control_state;
+
+ /*
+ * Update baud rate.
+ * Do not attempt to cache old rates and skip settings,
+ * disconnects screw such tricks up completely.
+ * Premature optimization is the root of all evil.
+ */
+
+ /* reassert DTR and (maybe) RTS on transition from B0 */
+ if ((old_cflag & CBAUD) == B0) {
+ new_state = control_state | TIOCM_DTR;
+ /* don't set RTS if using hardware flow control */
+ if (!(old_cflag & CRTSCTS))
+ new_state |= TIOCM_RTS;
+ dbg(DEBUG_IF, "%u: from B0 - set DTR%s", cs->minor_index,
+ (new_state & TIOCM_RTS) ? " only" : "/RTS");
+ cs->ops->set_modem_ctrl(cs, control_state, new_state);
+ control_state = new_state;
+ }
+
+ cs->ops->baud_rate(cs, cflag & CBAUD);
+
+ if ((cflag & CBAUD) == B0) {
+ /* Drop RTS and DTR */
+ dbg(DEBUG_IF, "%u: to B0 - drop DTR/RTS", cs->minor_index);
+ new_state = control_state & ~(TIOCM_DTR | TIOCM_RTS);
+ cs->ops->set_modem_ctrl(cs, control_state, new_state);
+ control_state = new_state;
+ }
+
+ /*
+ * Update line control register (LCR)
+ */
+
+ cs->ops->set_line_ctrl(cs, cflag);
+
+#if 0
+ //FIXME this hangs M101 [ts 2005-03-09]
+ //FIXME do we need this?
+ /*
+ * Set flow control: well, I do not really now how to handle DTR/RTS.
+ * Just do what we have seen with SniffUSB on Win98.
+ */
+ /* Drop DTR/RTS if no flow control otherwise assert */
+ dbg(DEBUG_IF, "%u: control_state %x", cs->minor_index, control_state);
+ new_state = control_state;
+ if ((iflag & IXOFF) || (iflag & IXON) || (cflag & CRTSCTS))
+ new_state |= TIOCM_DTR | TIOCM_RTS;
+ else
+ new_state &= ~(TIOCM_DTR | TIOCM_RTS);
+ if (new_state != control_state) {
+ dbg(DEBUG_IF, "%u: new_state %x", cs->minor_index, new_state);
+ gigaset_set_modem_ctrl(cs, control_state, new_state); // FIXME: mct_u232.c sets the old state here. is this a bug?
+ control_state = new_state;
+ }
+#endif
+
+ /* save off the modified port settings */
+ cs->control_state = control_state;
+
+out:
+ up(&cs->sem);
+}
+
+
+/* wakeup tasklet for the write operation */
+static void if_wake(unsigned long data)
+{
+ struct cardstate *cs = (struct cardstate *) data;
+ struct tty_struct *tty;
+
+ tty = cs->tty;
+ if (!tty)
+ return;
+
+ if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
+ tty->ldisc.write_wakeup) {
+ dbg(DEBUG_IF, "write wakeup call");
+ tty->ldisc.write_wakeup(tty);
+ }
+
+ wake_up_interruptible(&tty->write_wait);
+}
+
+/*** interface to common ***/
+
+void gigaset_if_init(struct cardstate *cs)
+{
+ struct gigaset_driver *drv;
+
+ drv = cs->driver;
+ if (!drv->have_tty)
+ return;
+
+ tasklet_init(&cs->if_wake_tasklet, &if_wake, (unsigned long) cs);
+ tty_register_device(drv->tty, cs->minor_index, NULL);
+}
+
+void gigaset_if_free(struct cardstate *cs)
+{
+ struct gigaset_driver *drv;
+
+ drv = cs->driver;
+ if (!drv->have_tty)
+ return;
+
+ tasklet_disable(&cs->if_wake_tasklet);
+ tasklet_kill(&cs->if_wake_tasklet);
+ tty_unregister_device(drv->tty, cs->minor_index);
+}
+
+void gigaset_if_receive(struct cardstate *cs,
+ unsigned char *buffer, size_t len)
+{
+ unsigned long flags;
+ struct tty_struct *tty;
+
+ spin_lock_irqsave(&cs->lock, flags);
+ if ((tty = cs->tty) == NULL)
+ dbg(DEBUG_ANY, "receive on closed device");
+ else {
+ tty_buffer_request_room(tty, len);
+ tty_insert_flip_string(tty, buffer, len);
+ tty_flip_buffer_push(tty);
+ }
+ spin_unlock_irqrestore(&cs->lock, flags);
+}
+EXPORT_SYMBOL_GPL(gigaset_if_receive);
+
+/* gigaset_if_initdriver
+ * Initialize tty interface.
+ * parameters:
+ * drv Driver
+ * procname Name of the driver (e.g. for /proc/tty/drivers)
+ * devname Name of the device files (prefix without minor number)
+ * devfsname Devfs name of the device files without %d
+ */
+void gigaset_if_initdriver(struct gigaset_driver *drv, const char *procname,
+ const char *devname, const char *devfsname)
+{
+ unsigned minors = drv->minors;
+ int ret;
+ struct tty_driver *tty;
+
+ drv->have_tty = 0;
+
+ if ((drv->tty = alloc_tty_driver(minors)) == NULL)
+ goto enomem;
+ tty = drv->tty;
+
+ tty->magic = TTY_DRIVER_MAGIC,
+ tty->major = GIG_MAJOR,
+ tty->type = TTY_DRIVER_TYPE_SERIAL,
+ tty->subtype = SERIAL_TYPE_NORMAL,
+ tty->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS,
+
+ tty->driver_name = procname;
+ tty->name = devname;
+ tty->minor_start = drv->minor;
+ tty->num = drv->minors;
+
+ tty->owner = THIS_MODULE;
+ tty->devfs_name = devfsname;
+
+ tty->init_termios = tty_std_termios; //FIXME
+ tty->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL; //FIXME
+ tty_set_operations(tty, &if_ops);
+
+ ret = tty_register_driver(tty);
+ if (ret < 0) {
+ warn("failed to register tty driver (error %d)", ret);
+ goto error;
+ }
+ dbg(DEBUG_IF, "tty driver initialized");
+ drv->have_tty = 1;
+ return;
+
+enomem:
+ warn("could not allocate tty structures");
+error:
+ if (drv->tty)
+ put_tty_driver(drv->tty);
+}
+
+void gigaset_if_freedriver(struct gigaset_driver *drv)
+{
+ if (!drv->have_tty)
+ return;
+
+ drv->have_tty = 0;
+ tty_unregister_driver(drv->tty);
+ put_tty_driver(drv->tty);
+}