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