574 lines
13 KiB
C
574 lines
13 KiB
C
/* Hey EMACS -*- linux-c -*-
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*
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* tipar - low level driver for handling a parallel link cable designed
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* for Texas Instruments graphing calculators (http://lpg.ticalc.org).
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* A part of the TiLP project.
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*
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* Copyright (C) 2000-2002, Romain Lievin <roms@lpg.ticalc.org>
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* under the terms of the GNU General Public License.
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*
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* Various fixes & clean-up from the Linux Kernel Mailing List
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* (Alan Cox, Richard B. Johnson, Christoph Hellwig).
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*/
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/* This driver should, in theory, work with any parallel port that has an
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* appropriate low-level driver; all I/O is done through the parport
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* abstraction layer.
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*
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* If this driver is built into the kernel, you can configure it using the
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* kernel command-line. For example:
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*
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* tipar=timeout,delay (set timeout and delay)
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*
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* If the driver is loaded as a module, similar functionality is available
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* using module parameters. The equivalent of the above commands would be:
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*
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* # insmod tipar timeout=15 delay=10
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*/
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/* COMPATIBILITY WITH OLD KERNELS
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*
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* Usually, parallel cables were bound to ports at
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* particular I/O addresses, as follows:
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*
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* tipar0 0x378
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* tipar1 0x278
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* tipar2 0x3bc
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*
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*
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* This driver, by default, binds tipar devices according to parport and
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* the minor number.
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*
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*/
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#undef DEBUG /* change to #define to get debugging
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* output - for pr_debug() */
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/delay.h>
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#include <linux/fcntl.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <asm/uaccess.h>
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#include <linux/ioport.h>
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#include <asm/io.h>
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#include <linux/bitops.h>
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#include <linux/devfs_fs_kernel.h> /* DevFs support */
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#include <linux/parport.h> /* Our code depend on parport */
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#include <linux/device.h>
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/*
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* TI definitions
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*/
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#include <linux/ticable.h>
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/*
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* Version Information
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*/
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#define DRIVER_VERSION "1.19"
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#define DRIVER_AUTHOR "Romain Lievin <roms@lpg.ticalc.org>"
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#define DRIVER_DESC "Device driver for TI/PC parallel link cables"
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#define DRIVER_LICENSE "GPL"
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#define VERSION(ver,rel,seq) (((ver)<<16) | ((rel)<<8) | (seq))
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/* ----- global variables --------------------------------------------- */
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struct tipar_struct {
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struct pardevice *dev; /* Parport device entry */
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};
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#define PP_NO 3
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static struct tipar_struct table[PP_NO];
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static int delay = IO_DELAY; /* inter-bit delay in microseconds */
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static int timeout = TIMAXTIME; /* timeout in tenth of seconds */
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static unsigned int tp_count; /* tipar count */
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static unsigned long opened; /* opened devices */
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static struct class *tipar_class;
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/* --- macros for parport access -------------------------------------- */
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#define r_dtr(x) (parport_read_data(table[(x)].dev->port))
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#define r_str(x) (parport_read_status(table[(x)].dev->port))
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#define w_ctr(x,y) (parport_write_control(table[(x)].dev->port, (y)))
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#define w_dtr(x,y) (parport_write_data(table[(x)].dev->port, (y)))
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/* --- setting states on the D-bus with the right timing: ------------- */
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static inline void
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outbyte(int value, int minor)
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{
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w_dtr(minor, value);
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}
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static inline int
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inbyte(int minor)
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{
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return (r_str(minor));
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}
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static inline void
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init_ti_parallel(int minor)
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{
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outbyte(3, minor);
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}
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/* ----- global defines ----------------------------------------------- */
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#define START(x) { x = jiffies + (HZ * timeout) / 10; }
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#define WAIT(x) { \
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if (time_before((x), jiffies)) return -1; \
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if (need_resched()) schedule(); }
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/* ----- D-bus bit-banging functions ---------------------------------- */
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/* D-bus protocol (45kbit/s max):
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1 0 0
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_______ ______|______ __________|________ __________
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Red : ________ | ____ | ____
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_ ____________|________ ______|__________ _____
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White: ________ | ______ | _______
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*/
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/* Try to transmit a byte on the specified port (-1 if error). */
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static int
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put_ti_parallel(int minor, unsigned char data)
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{
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unsigned int bit;
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unsigned long max;
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for (bit = 0; bit < 8; bit++) {
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if (data & 1) {
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outbyte(2, minor);
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START(max);
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do {
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WAIT(max);
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} while (inbyte(minor) & 0x10);
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outbyte(3, minor);
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START(max);
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do {
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WAIT(max);
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} while (!(inbyte(minor) & 0x10));
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} else {
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outbyte(1, minor);
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START(max);
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do {
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WAIT(max);
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} while (inbyte(minor) & 0x20);
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outbyte(3, minor);
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START(max);
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do {
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WAIT(max);
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} while (!(inbyte(minor) & 0x20));
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}
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data >>= 1;
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udelay(delay);
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if (need_resched())
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schedule();
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}
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return 0;
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}
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/* Receive a byte on the specified port or -1 if error. */
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static int
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get_ti_parallel(int minor)
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{
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unsigned int bit;
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unsigned char v, data = 0;
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unsigned long max;
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for (bit = 0; bit < 8; bit++) {
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START(max);
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do {
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WAIT(max);
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} while ((v = inbyte(minor) & 0x30) == 0x30);
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if (v == 0x10) {
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data = (data >> 1) | 0x80;
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outbyte(1, minor);
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START(max);
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do {
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WAIT(max);
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} while (!(inbyte(minor) & 0x20));
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outbyte(3, minor);
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} else {
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data = data >> 1;
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outbyte(2, minor);
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START(max);
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do {
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WAIT(max);
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} while (!(inbyte(minor) & 0x10));
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outbyte(3, minor);
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}
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udelay(delay);
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if (need_resched())
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schedule();
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}
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return (int) data;
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}
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/* Try to detect a parallel link cable on the specified port */
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static int
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probe_ti_parallel(int minor)
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{
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int i;
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int seq[] = { 0x00, 0x20, 0x10, 0x30 };
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for (i = 3; i >= 0; i--) {
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outbyte(3, minor);
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outbyte(i, minor);
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udelay(delay);
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pr_debug("tipar: Probing -> %i: 0x%02x 0x%02x\n", i,
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data & 0x30, seq[i]);
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if ((inbyte(minor) & 0x30) != seq[i]) {
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outbyte(3, minor);
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return -1;
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}
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}
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outbyte(3, minor);
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return 0;
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}
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/* ----- kernel module functions--------------------------------------- */
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static int
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tipar_open(struct inode *inode, struct file *file)
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{
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unsigned int minor = iminor(inode) - TIPAR_MINOR;
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if (tp_count == 0 || minor > tp_count - 1)
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return -ENXIO;
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if (test_and_set_bit(minor, &opened))
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return -EBUSY;
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if (!table[minor].dev) {
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printk(KERN_ERR "%s: NULL device for minor %u\n",
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__FUNCTION__, minor);
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return -ENXIO;
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}
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parport_claim_or_block(table[minor].dev);
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init_ti_parallel(minor);
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parport_release(table[minor].dev);
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return nonseekable_open(inode, file);
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}
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static int
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tipar_close(struct inode *inode, struct file *file)
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{
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unsigned int minor = iminor(inode) - TIPAR_MINOR;
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if (minor > tp_count - 1)
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return -ENXIO;
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clear_bit(minor, &opened);
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return 0;
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}
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static ssize_t
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tipar_write (struct file *file, const char __user *buf, size_t count,
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loff_t * ppos)
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{
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unsigned int minor = iminor(file->f_dentry->d_inode) - TIPAR_MINOR;
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ssize_t n;
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parport_claim_or_block(table[minor].dev);
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for (n = 0; n < count; n++) {
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unsigned char b;
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if (get_user(b, buf + n)) {
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n = -EFAULT;
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goto out;
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}
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if (put_ti_parallel(minor, b) == -1) {
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init_ti_parallel(minor);
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n = -ETIMEDOUT;
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goto out;
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}
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}
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out:
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parport_release(table[minor].dev);
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return n;
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}
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static ssize_t
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tipar_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
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{
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int b = 0;
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unsigned int minor = iminor(file->f_dentry->d_inode) - TIPAR_MINOR;
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ssize_t retval = 0;
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ssize_t n = 0;
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if (count == 0)
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return 0;
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parport_claim_or_block(table[minor].dev);
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while (n < count) {
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b = get_ti_parallel(minor);
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if (b == -1) {
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init_ti_parallel(minor);
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retval = -ETIMEDOUT;
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goto out;
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} else {
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if (put_user(b, buf + n)) {
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retval = -EFAULT;
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break;
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} else
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retval = ++n;
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}
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/* Non-blocking mode : try again ! */
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if (file->f_flags & O_NONBLOCK) {
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retval = -EAGAIN;
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goto out;
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}
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/* Signal pending, try again ! */
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if (signal_pending(current)) {
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retval = -ERESTARTSYS;
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goto out;
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}
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if (need_resched())
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schedule();
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}
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out:
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parport_release(table[minor].dev);
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return retval;
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}
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static int
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tipar_ioctl(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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int retval = 0;
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switch (cmd) {
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case IOCTL_TIPAR_DELAY:
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delay = (int)arg; //get_user(delay, &arg);
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break;
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case IOCTL_TIPAR_TIMEOUT:
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if (arg != 0)
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timeout = (int)arg;
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else
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retval = -EINVAL;
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break;
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default:
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retval = -ENOTTY;
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break;
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}
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return retval;
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}
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/* ----- kernel module registering ------------------------------------ */
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static struct file_operations tipar_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.read = tipar_read,
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.write = tipar_write,
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.ioctl = tipar_ioctl,
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.open = tipar_open,
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.release = tipar_close,
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};
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/* --- initialisation code ------------------------------------- */
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#ifndef MODULE
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/* You must set these - there is no sane way to probe for this cable.
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* You can use 'tipar=timeout,delay' to set these now. */
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static int __init
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tipar_setup(char *str)
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{
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int ints[3];
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str = get_options(str, ARRAY_SIZE(ints), ints);
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if (ints[0] > 0) {
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if (ints[1] != 0)
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timeout = ints[1];
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else
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printk(KERN_WARNING "tipar: bad timeout value (0), "
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"using default value instead");
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if (ints[0] > 1) {
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delay = ints[2];
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}
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}
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return 1;
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}
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#endif
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/*
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* Register our module into parport.
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* Pass also 2 callbacks functions to parport: a pre-emptive function and an
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* interrupt handler function (unused).
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* Display a message such "tipar0: using parport0 (polling)".
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*/
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static int
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tipar_register(int nr, struct parport *port)
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{
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int err = 0;
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/* Register our module into parport */
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table[nr].dev = parport_register_device(port, "tipar",
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NULL, NULL, NULL, 0,
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(void *) &table[nr]);
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if (table[nr].dev == NULL) {
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err = 1;
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goto out;
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}
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class_device_create(tipar_class, NULL, MKDEV(TIPAR_MAJOR,
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TIPAR_MINOR + nr), NULL, "par%d", nr);
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/* Use devfs, tree: /dev/ticables/par/[0..2] */
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err = devfs_mk_cdev(MKDEV(TIPAR_MAJOR, TIPAR_MINOR + nr),
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S_IFCHR | S_IRUGO | S_IWUGO,
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"ticables/par/%d", nr);
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if (err)
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goto out_class;
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/* Display informations */
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pr_info("tipar%d: using %s (%s)\n", nr, port->name, (port->irq ==
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PARPORT_IRQ_NONE) ? "polling" : "interrupt-driven");
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if (probe_ti_parallel(nr) != -1)
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pr_info("tipar%d: link cable found\n", nr);
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else
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pr_info("tipar%d: link cable not found\n", nr);
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err = 0;
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goto out;
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out_class:
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class_device_destroy(tipar_class, MKDEV(TIPAR_MAJOR, TIPAR_MINOR + nr));
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class_destroy(tipar_class);
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out:
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return err;
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}
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static void
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tipar_attach(struct parport *port)
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{
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if (tp_count == PP_NO) {
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pr_info("tipar: ignoring parallel port (max. %d)\n", PP_NO);
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return;
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}
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if (!tipar_register(tp_count, port))
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tp_count++;
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}
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static void
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tipar_detach(struct parport *port)
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{
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/* Nothing to do */
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}
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static struct parport_driver tipar_driver = {
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.name = "tipar",
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.attach = tipar_attach,
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.detach = tipar_detach,
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};
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static int __init
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tipar_init_module(void)
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{
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int err = 0;
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pr_info("tipar: parallel link cable driver, version %s\n",
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DRIVER_VERSION);
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if (register_chrdev(TIPAR_MAJOR, "tipar", &tipar_fops)) {
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printk(KERN_ERR "tipar: unable to get major %d\n", TIPAR_MAJOR);
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err = -EIO;
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goto out;
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}
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/* Use devfs with tree: /dev/ticables/par/[0..2] */
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devfs_mk_dir("ticables/par");
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tipar_class = class_create(THIS_MODULE, "ticables");
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if (IS_ERR(tipar_class)) {
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err = PTR_ERR(tipar_class);
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goto out_chrdev;
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}
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if (parport_register_driver(&tipar_driver)) {
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printk(KERN_ERR "tipar: unable to register with parport\n");
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err = -EIO;
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goto out_class;
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}
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err = 0;
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goto out;
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out_class:
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class_destroy(tipar_class);
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out_chrdev:
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devfs_remove("ticables/par");
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unregister_chrdev(TIPAR_MAJOR, "tipar");
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out:
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return err;
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}
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static void __exit
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tipar_cleanup_module(void)
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{
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unsigned int i;
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/* Unregistering module */
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parport_unregister_driver(&tipar_driver);
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unregister_chrdev(TIPAR_MAJOR, "tipar");
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for (i = 0; i < PP_NO; i++) {
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if (table[i].dev == NULL)
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continue;
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parport_unregister_device(table[i].dev);
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class_device_destroy(tipar_class, MKDEV(TIPAR_MAJOR, i));
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devfs_remove("ticables/par/%d", i);
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}
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class_destroy(tipar_class);
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devfs_remove("ticables/par");
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pr_info("tipar: module unloaded\n");
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}
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/* --------------------------------------------------------------------- */
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__setup("tipar=", tipar_setup);
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module_init(tipar_init_module);
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module_exit(tipar_cleanup_module);
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE(DRIVER_LICENSE);
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout, "Timeout (default=1.5 seconds)");
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module_param(delay, int, 0);
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MODULE_PARM_DESC(delay, "Inter-bit delay (default=10 microseconds)");
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