text: /*
   * Copyright 2004 Digi International (www.digi.com)
   *      Scott H Kilau <Scott_Kilau at digi dot com>
   *
   * 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, or (at your option)
   * any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
   * PURPOSE.  See the GNU General Public License for more details.
   */
  
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/ctype.h>
  #include <linux/string.h>
  #include <linux/serial_reg.h>
  #include <linux/device.h>
  #include <linux/pci.h>
  #include <linux/kdev_t.h>
  
  #include "dgnc_driver.h"
  #include "dgnc_mgmt.h"
  
  
  static ssize_t dgnc_driver_version_show(struct device_driver *ddp, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%s\n", DG_PART);
  }
  static DRIVER_ATTR(version, S_IRUSR, dgnc_driver_version_show, NULL);
  
  
  static ssize_t dgnc_driver_boards_show(struct device_driver *ddp, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%d\n", dgnc_NumBoards);
  }
  static DRIVER_ATTR(boards, S_IRUSR, dgnc_driver_boards_show, NULL);
  
  
  static ssize_t dgnc_driver_maxboards_show(struct device_driver *ddp, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%d\n", MAXBOARDS);
  }
  static DRIVER_ATTR(maxboards, S_IRUSR, dgnc_driver_maxboards_show, NULL);
  
  
  static ssize_t dgnc_driver_pollrate_show(struct device_driver *ddp, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%dms\n", dgnc_poll_tick);
  }
  
  static ssize_t dgnc_driver_pollrate_store(struct device_driver *ddp,
  					  const char *buf, size_t count)
  {
  	int ret;
  
  	ret = sscanf(buf, "%d\n", &dgnc_poll_tick);
  	if (ret != 1)
  		return -EINVAL;
  	return count;
  }
  static DRIVER_ATTR(pollrate, (S_IRUSR | S_IWUSR), dgnc_driver_pollrate_show,
  		   dgnc_driver_pollrate_store);
  
  
  void dgnc_create_driver_sysfiles(struct pci_driver *dgnc_driver)
  {
  	int rc = 0;
  	struct device_driver *driverfs = &dgnc_driver->driver;
  
  	rc |= driver_create_file(driverfs, &driver_attr_version);
  	rc |= driver_create_file(driverfs, &driver_attr_boards);
  	rc |= driver_create_file(driverfs, &driver_attr_maxboards);
  	rc |= driver_create_file(driverfs, &driver_attr_pollrate);
  	if (rc)
  		pr_err("DGNC: sysfs driver_create_file failed!\n");
  }
  
  
  void dgnc_remove_driver_sysfiles(struct pci_driver *dgnc_driver)
  {
  	struct device_driver *driverfs = &dgnc_driver->driver;
  
  	driver_remove_file(driverfs, &driver_attr_version);
  	driver_remove_file(driverfs, &driver_attr_boards);
  	driver_remove_file(driverfs, &driver_attr_maxboards);
  	driver_remove_file(driverfs, &driver_attr_pollrate);
  }
  
  
  #define DGNC_VERIFY_BOARD(p, bd)				\
  	do {							\
  		if (!p)						\
  			return 0;				\
  								\
  		bd = dev_get_drvdata(p);			\
  		if (!bd || bd->magic != DGNC_BOARD_MAGIC)	\
  			return 0;				\
  		if (bd->state != BOARD_READY)			\
  			return 0;				\
  	} while (0)
  
  
  
  static ssize_t dgnc_vpd_show(struct device *p, struct device_attribute *attr,
  			     char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	count += sprintf(buf + count,
  		"\n      0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F");
  	for (i = 0; i < 0x40 * 2; i++) {
  		if (!(i % 16))
  			count += sprintf(buf + count, "\n%04X ", i * 2);
  		count += sprintf(buf + count, "%02X ", bd->vpd[i]);
  	}
  	count += sprintf(buf + count, "\n");
  
  	return count;
  }
  static DEVICE_ATTR(vpd, S_IRUSR, dgnc_vpd_show, NULL);
  
  static ssize_t dgnc_serial_number_show(struct device *p,
  				       struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	if (bd->serial_num[0] == '\0')
  		count += sprintf(buf + count, "<UNKNOWN>\n");
  	else
  		count += sprintf(buf + count, "%s\n", bd->serial_num);
  
  	return count;
  }
  static DEVICE_ATTR(serial_number, S_IRUSR, dgnc_serial_number_show, NULL);
  
  
  static ssize_t dgnc_ports_state_show(struct device *p,
  				     struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count += snprintf(buf + count, PAGE_SIZE - count,
  			"%d %s\n", bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_open_count ? "Open" : "Closed");
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_state, S_IRUSR, dgnc_ports_state_show, NULL);
  
  
  static ssize_t dgnc_ports_baud_show(struct device *p,
  				    struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count +=  snprintf(buf + count, PAGE_SIZE - count,
  			"%d %d\n", bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_old_baud);
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_baud, S_IRUSR, dgnc_ports_baud_show, NULL);
  
  
  static ssize_t dgnc_ports_msignals_show(struct device *p,
  					struct device_attribute *attr,
  					char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		if (bd->channels[i]->ch_open_count) {
  			count += snprintf(buf + count, PAGE_SIZE - count,
  				"%d %s %s %s %s %s %s\n",
  				bd->channels[i]->ch_portnum,
  				(bd->channels[i]->ch_mostat & UART_MCR_RTS) ? "RTS" : "",
  				(bd->channels[i]->ch_mistat & UART_MSR_CTS) ? "CTS" : "",
  				(bd->channels[i]->ch_mostat & UART_MCR_DTR) ? "DTR" : "",
  				(bd->channels[i]->ch_mistat & UART_MSR_DSR) ? "DSR" : "",
  				(bd->channels[i]->ch_mistat & UART_MSR_DCD) ? "DCD" : "",
  				(bd->channels[i]->ch_mistat & UART_MSR_RI)  ? "RI"  : "");
  		} else {
  			count += snprintf(buf + count, PAGE_SIZE - count,
  				"%d\n", bd->channels[i]->ch_portnum);
  		}
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_msignals, S_IRUSR, dgnc_ports_msignals_show, NULL);
  
  
  static ssize_t dgnc_ports_iflag_show(struct device *p,
  				     struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
  			bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_c_iflag);
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_iflag, S_IRUSR, dgnc_ports_iflag_show, NULL);
  
  
  static ssize_t dgnc_ports_cflag_show(struct device *p,
  				     struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
  			bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_c_cflag);
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_cflag, S_IRUSR, dgnc_ports_cflag_show, NULL);
  
  
  static ssize_t dgnc_ports_oflag_show(struct device *p,
  				     struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
  			bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_c_oflag);
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_oflag, S_IRUSR, dgnc_ports_oflag_show, NULL);
  
  
  static ssize_t dgnc_ports_lflag_show(struct device *p,
  				     struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
  			bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_c_lflag);
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_lflag, S_IRUSR, dgnc_ports_lflag_show, NULL);
  
  
  static ssize_t dgnc_ports_digi_flag_show(struct device *p,
  					 struct device_attribute *attr,
  					 char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
  			bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_digi.digi_flags);
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_digi_flag, S_IRUSR, dgnc_ports_digi_flag_show, NULL);
  
  
  static ssize_t dgnc_ports_rxcount_show(struct device *p,
  				       struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count += snprintf(buf + count, PAGE_SIZE - count, "%d %ld\n",
  			bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_rxcount);
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_rxcount, S_IRUSR, dgnc_ports_rxcount_show, NULL);
  
  
  static ssize_t dgnc_ports_txcount_show(struct device *p,
  				       struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	int count = 0;
  	int i = 0;
  
  	DGNC_VERIFY_BOARD(p, bd);
  
  	for (i = 0; i < bd->nasync; i++) {
  		count += snprintf(buf + count, PAGE_SIZE - count, "%d %ld\n",
  			bd->channels[i]->ch_portnum,
  			bd->channels[i]->ch_txcount);
  	}
  	return count;
  }
  static DEVICE_ATTR(ports_txcount, S_IRUSR, dgnc_ports_txcount_show, NULL);
  
  
  /* this function creates the sys files that will export each signal status
   * to sysfs each value will be put in a separate filename
   */
  void dgnc_create_ports_sysfiles(struct dgnc_board *bd)
  {
  	int rc = 0;
  
  	dev_set_drvdata(&bd->pdev->dev, bd);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_state);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_baud);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_msignals);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_iflag);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_cflag);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_oflag);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_lflag);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_digi_flag);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_rxcount);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_ports_txcount);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_vpd);
  	rc |= device_create_file(&(bd->pdev->dev), &dev_attr_serial_number);
  	if (rc)
  		dev_err(&bd->pdev->dev, "dgnc: sysfs device_create_file failed!\n");
  }
  
  
  /* removes all the sys files created for that port */
  void dgnc_remove_ports_sysfiles(struct dgnc_board *bd)
  {
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_state);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_baud);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_msignals);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_iflag);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_cflag);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_oflag);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_lflag);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_digi_flag);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_rxcount);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_ports_txcount);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_vpd);
  	device_remove_file(&(bd->pdev->dev), &dev_attr_serial_number);
  }
  
  
  static ssize_t dgnc_tty_state_show(struct device *d,
  				   struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%s",
  			un->un_open_count ? "Open" : "Closed");
  }
  static DEVICE_ATTR(state, S_IRUSR, dgnc_tty_state_show, NULL);
  
  
  static ssize_t dgnc_tty_baud_show(struct device *d,
  				  struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%d\n", ch->ch_old_baud);
  }
  static DEVICE_ATTR(baud, S_IRUSR, dgnc_tty_baud_show, NULL);
  
  
  static ssize_t dgnc_tty_msignals_show(struct device *d,
  				      struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	if (ch->ch_open_count) {
  		return snprintf(buf, PAGE_SIZE, "%s %s %s %s %s %s\n",
  			(ch->ch_mostat & UART_MCR_RTS) ? "RTS" : "",
  			(ch->ch_mistat & UART_MSR_CTS) ? "CTS" : "",
  			(ch->ch_mostat & UART_MCR_DTR) ? "DTR" : "",
  			(ch->ch_mistat & UART_MSR_DSR) ? "DSR" : "",
  			(ch->ch_mistat & UART_MSR_DCD) ? "DCD" : "",
  			(ch->ch_mistat & UART_MSR_RI)  ? "RI"  : "");
  	}
  	return 0;
  }
  static DEVICE_ATTR(msignals, S_IRUSR, dgnc_tty_msignals_show, NULL);
  
  
  static ssize_t dgnc_tty_iflag_show(struct device *d,
  				   struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_c_iflag);
  }
  static DEVICE_ATTR(iflag, S_IRUSR, dgnc_tty_iflag_show, NULL);
  
  
  static ssize_t dgnc_tty_cflag_show(struct device *d,
  				   struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_c_cflag);
  }
  static DEVICE_ATTR(cflag, S_IRUSR, dgnc_tty_cflag_show, NULL);
  
  
  static ssize_t dgnc_tty_oflag_show(struct device *d,
  				   struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_c_oflag);
  }
  static DEVICE_ATTR(oflag, S_IRUSR, dgnc_tty_oflag_show, NULL);
  
  
  static ssize_t dgnc_tty_lflag_show(struct device *d,
  				   struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_c_lflag);
  }
  static DEVICE_ATTR(lflag, S_IRUSR, dgnc_tty_lflag_show, NULL);
  
  
  static ssize_t dgnc_tty_digi_flag_show(struct device *d,
  				       struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_digi.digi_flags);
  }
  static DEVICE_ATTR(digi_flag, S_IRUSR, dgnc_tty_digi_flag_show, NULL);
  
  
  static ssize_t dgnc_tty_rxcount_show(struct device *d,
  				     struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%ld\n", ch->ch_rxcount);
  }
  static DEVICE_ATTR(rxcount, S_IRUSR, dgnc_tty_rxcount_show, NULL);
  
  
  static ssize_t dgnc_tty_txcount_show(struct device *d,
  				     struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%ld\n", ch->ch_txcount);
  }
  static DEVICE_ATTR(txcount, S_IRUSR, dgnc_tty_txcount_show, NULL);
  
  
  static ssize_t dgnc_tty_name_show(struct device *d,
  				  struct device_attribute *attr, char *buf)
  {
  	struct dgnc_board *bd;
  	struct channel_t *ch;
  	struct un_t *un;
  
  	if (!d)
  		return 0;
  	un = dev_get_drvdata(d);
  	if (!un || un->magic != DGNC_UNIT_MAGIC)
  		return 0;
  	ch = un->un_ch;
  	if (!ch || ch->magic != DGNC_CHANNEL_MAGIC)
  		return 0;
  	bd = ch->ch_bd;
  	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
  		return 0;
  	if (bd->state != BOARD_READY)
  		return 0;
  
  	return snprintf(buf, PAGE_SIZE, "%sn%d%c\n",
  		(un->un_type == DGNC_PRINT) ? "pr" : "tty",
  		bd->boardnum + 1, 'a' + ch->ch_portnum);
  }
  static DEVICE_ATTR(custom_name, S_IRUSR, dgnc_tty_name_show, NULL);
  
  
  static struct attribute *dgnc_sysfs_tty_entries[] = {
  	&dev_attr_state.attr,
  	&dev_attr_baud.attr,
  	&dev_attr_msignals.attr,
  	&dev_attr_iflag.attr,
  	&dev_attr_cflag.attr,
  	&dev_attr_oflag.attr,
  	&dev_attr_lflag.attr,
  	&dev_attr_digi_flag.attr,
  	&dev_attr_rxcount.attr,
  	&dev_attr_txcount.attr,
  	&dev_attr_custom_name.attr,
  	NULL
  };
  
  
  static struct attribute_group dgnc_tty_attribute_group = {
  	.name = NULL,
  	.attrs = dgnc_sysfs_tty_entries,
  };
  
  
  void dgnc_create_tty_sysfs(struct un_t *un, struct device *c)
  {
  	int ret;
  
  	ret = sysfs_create_group(&c->kobj, &dgnc_tty_attribute_group);
  	if (ret) {
  		dev_err(c, "dgnc: failed to create sysfs tty device attributes.\n");
  		sysfs_remove_group(&c->kobj, &dgnc_tty_attribute_group);
  		return;
  	}
  
  	dev_set_drvdata(c, un);
  
  }
  
  
  void dgnc_remove_tty_sysfs(struct device *c)
  {
  	sysfs_remove_group(&c->kobj, &dgnc_tty_attribute_group);
  }
  
  