blob: 19bf403f9db2026dc8e20d7faea0a4eeba9ee970 [file] [log] [blame]
/*
* mos7720.c
* Controls the Moschip 7720 usb to dual port serial convertor
*
* Copyright 2006 Moschip Semiconductor Tech. Ltd.
*
* 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, version 2 of the License.
*
* Developed by:
* VijayaKumar.G.N. <vijaykumar@aspirecom.net>
* AjayKumar <ajay@aspirecom.net>
* Gurudeva.N. <gurudev@aspirecom.net>
*
* Cleaned up from the original by:
* Greg Kroah-Hartman <gregkh@suse.de>
*
* Originally based on drivers/usb/serial/io_edgeport.c which is:
* Copyright (C) 2000 Inside Out Networks, All rights reserved.
* Copyright (C) 2001-2002 Greg Kroah-Hartman <greg@kroah.com>
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <asm/uaccess.h>
/*
* Version Information
*/
#define DRIVER_VERSION "1.0.0.4F"
#define DRIVER_AUTHOR "Aspire Communications pvt Ltd."
#define DRIVER_DESC "Moschip USB Serial Driver"
/* default urb timeout */
#define MOS_WDR_TIMEOUT (HZ * 5)
#define MOS_PORT1 0x0200
#define MOS_PORT2 0x0300
#define MOS_VENREG 0x0000
#define MOS_MAX_PORT 0x02
#define MOS_WRITE 0x0E
#define MOS_READ 0x0D
/* Interrupt Rotinue Defines */
#define SERIAL_IIR_RLS 0x06
#define SERIAL_IIR_RDA 0x04
#define SERIAL_IIR_CTI 0x0c
#define SERIAL_IIR_THR 0x02
#define SERIAL_IIR_MS 0x00
#define NUM_URBS 16 /* URB Count */
#define URB_TRANSFER_BUFFER_SIZE 32 /* URB Size */
/* This structure holds all of the local port information */
struct moschip_port
{
__u8 shadowLCR; /* last LCR value received */
__u8 shadowMCR; /* last MCR value received */
__u8 shadowMSR; /* last MSR value received */
char open;
struct async_icount icount;
struct usb_serial_port *port; /* loop back to the owner */
struct urb *write_urb_pool[NUM_URBS];
};
/* This structure holds all of the individual serial device information */
struct moschip_serial
{
int interrupt_started;
};
static int debug;
#define USB_VENDOR_ID_MOSCHIP 0x9710
#define MOSCHIP_DEVICE_ID_7720 0x7720
#define MOSCHIP_DEVICE_ID_7715 0x7715
static struct usb_device_id moschip_port_id_table [] = {
{ USB_DEVICE(USB_VENDOR_ID_MOSCHIP,MOSCHIP_DEVICE_ID_7720) },
{ } /* terminating entry */
};
MODULE_DEVICE_TABLE(usb, moschip_port_id_table);
/*
* mos7720_interrupt_callback
* this is the callback function for when we have received data on the
* interrupt endpoint.
*/
static void mos7720_interrupt_callback(struct urb *urb)
{
int result;
int length;
__u32 *data;
unsigned int status;
__u8 sp1;
__u8 sp2;
__u8 st;
dbg("%s"," : Entering\n");
if (!urb) {
dbg("%s","Invalid Pointer !!!!:\n");
return;
}
switch (urb->status) {
case 0:
/* success */
break;
case -ECONNRESET:
case -ENOENT:
case -ESHUTDOWN:
/* this urb is terminated, clean up */
dbg("%s - urb shutting down with status: %d", __FUNCTION__,
urb->status);
return;
default:
dbg("%s - nonzero urb status received: %d", __FUNCTION__,
urb->status);
goto exit;
}
length = urb->actual_length;
data = urb->transfer_buffer;
/* Moschip get 4 bytes
* Byte 1 IIR Port 1 (port.number is 0)
* Byte 2 IIR Port 2 (port.number is 1)
* Byte 3 --------------
* Byte 4 FIFO status for both */
if (length && length > 4) {
dbg("Wrong data !!!");
return;
}
status = *data;
sp1 = (status & 0xff000000)>>24;
sp2 = (status & 0x00ff0000)>>16;
st = status & 0x000000ff;
if ((sp1 & 0x01) || (sp2 & 0x01)) {
/* No Interrupt Pending in both the ports */
dbg("No Interrupt !!!");
} else {
switch (sp1 & 0x0f) {
case SERIAL_IIR_RLS:
dbg("Serial Port 1: Receiver status error or address "
"bit detected in 9-bit mode\n");
break;
case SERIAL_IIR_CTI:
dbg("Serial Port 1: Receiver time out");
break;
case SERIAL_IIR_MS:
dbg("Serial Port 1: Modem status change");
break;
}
switch (sp2 & 0x0f) {
case SERIAL_IIR_RLS:
dbg("Serial Port 2: Receiver status error or address "
"bit detected in 9-bit mode");
break;
case SERIAL_IIR_CTI:
dbg("Serial Port 2: Receiver time out");
break;
case SERIAL_IIR_MS:
dbg("Serial Port 2: Modem status change");
break;
}
}
exit:
result = usb_submit_urb(urb, GFP_ATOMIC);
if (result)
dev_err(&urb->dev->dev,
"%s - Error %d submitting control urb\n",
__FUNCTION__, result);
return;
}
/*
* mos7720_bulk_in_callback
* this is the callback function for when we have received data on the
* bulk in endpoint.
*/
static void mos7720_bulk_in_callback(struct urb *urb)
{
int status;
unsigned char *data ;
struct usb_serial_port *port;
struct moschip_port *mos7720_port;
struct tty_struct *tty;
if (urb->status) {
dbg("nonzero read bulk status received: %d",urb->status);
return;
}
mos7720_port = urb->context;
if (!mos7720_port) {
dbg("%s","NULL mos7720_port pointer \n");
return ;
}
port = mos7720_port->port;
dbg("Entering...%s", __FUNCTION__);
data = urb->transfer_buffer;
tty = port->tty;
if (tty && urb->actual_length) {
tty_buffer_request_room(tty, urb->actual_length);
tty_insert_flip_string(tty, data, urb->actual_length);
tty_flip_buffer_push(tty);
}
if (!port->read_urb) {
dbg("URB KILLED !!!");
return;
}
if (port->read_urb->status != -EINPROGRESS) {
port->read_urb->dev = port->serial->dev;
status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
if (status)
dbg("usb_submit_urb(read bulk) failed, status = %d",
status);
}
}
/*
* mos7720_bulk_out_data_callback
* this is the callback function for when we have finished sending serial
* data on the bulk out endpoint.
*/
static void mos7720_bulk_out_data_callback(struct urb *urb)
{
struct moschip_port *mos7720_port;
struct tty_struct *tty;
if (urb->status) {
dbg("nonzero write bulk status received:%d", urb->status);
return;
}
mos7720_port = urb->context;
if (!mos7720_port) {
dbg("NULL mos7720_port pointer");
return ;
}
dbg("Entering .........");
tty = mos7720_port->port->tty;
if (tty && mos7720_port->open)
tty_wakeup(tty);
}
/*
* send_mos_cmd
* this function will be used for sending command to device
*/
static int send_mos_cmd(struct usb_serial *serial, __u8 request, __u16 value,
__u16 index, void *data)
{
int status;
unsigned int pipe;
u16 product = le16_to_cpu(serial->dev->descriptor.idProduct);
__u8 requesttype;
__u16 size = 0x0000;
if (value < MOS_MAX_PORT) {
if (product == MOSCHIP_DEVICE_ID_7715) {
value = value*0x100+0x100;
} else {
value = value*0x100+0x200;
}
} else {
value = 0x0000;
if ((product == MOSCHIP_DEVICE_ID_7715) &&
(index != 0x08)) {
dbg("serial->product== MOSCHIP_DEVICE_ID_7715");
//index = 0x01 ;
}
}
if (request == MOS_WRITE) {
request = (__u8)MOS_WRITE;
requesttype = (__u8)0x40;
value = value + (__u16)*((unsigned char *)data);
data = NULL;
pipe = usb_sndctrlpipe(serial->dev, 0);
} else {
request = (__u8)MOS_READ;
requesttype = (__u8)0xC0;
size = 0x01;
pipe = usb_rcvctrlpipe(serial->dev,0);
}
status = usb_control_msg(serial->dev, pipe, request, requesttype,
value, index, data, size, MOS_WDR_TIMEOUT);
if (status < 0)
dbg("Command Write failed Value %x index %x\n",value,index);
return status;
}
static int mos7720_open(struct usb_serial_port *port, struct file * filp)
{
struct usb_serial *serial;
struct usb_serial_port *port0;
struct urb *urb;
struct moschip_serial *mos7720_serial;
struct moschip_port *mos7720_port;
int response;
int port_number;
char data;
int j;
serial = port->serial;
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL)
return -ENODEV;
port0 = serial->port[0];
mos7720_serial = usb_get_serial_data(serial);
if (mos7720_serial == NULL || port0 == NULL)
return -ENODEV;
usb_clear_halt(serial->dev, port->write_urb->pipe);
usb_clear_halt(serial->dev, port->read_urb->pipe);
/* Initialising the write urb pool */
for (j = 0; j < NUM_URBS; ++j) {
urb = usb_alloc_urb(0,GFP_ATOMIC);
mos7720_port->write_urb_pool[j] = urb;
if (urb == NULL) {
err("No more urbs???");
continue;
}
urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
GFP_KERNEL);
if (!urb->transfer_buffer) {
err("%s-out of memory for urb buffers.", __FUNCTION__);
continue;
}
}
/* Initialize MCS7720 -- Write Init values to corresponding Registers
*
* Register Index
* 1 : IER
* 2 : FCR
* 3 : LCR
* 4 : MCR
*
* 0x08 : SP1/2 Control Reg
*/
port_number = port->number - port->serial->minor;
send_mos_cmd(port->serial, MOS_READ, port_number, UART_LSR, &data);
dbg("SS::%p LSR:%x\n",mos7720_port, data);
dbg("Check:Sending Command ..........");
data = 0x02;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT, 0x01, &data);
data = 0x02;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT, 0x02, &data);
data = 0x00;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x01, &data);
data = 0x00;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x02, &data);
data = 0xCF;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x02, &data);
data = 0x03;
mos7720_port->shadowLCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x03, &data);
data = 0x0b;
mos7720_port->shadowMCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x04, &data);
data = 0x0b;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x04, &data);
data = 0x00;
send_mos_cmd(serial, MOS_READ, MOS_MAX_PORT, 0x08, &data);
data = 0x00;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT, 0x08, &data);
/* data = 0x00;
send_mos_cmd(serial, MOS_READ, MOS_MAX_PORT, port_number + 1, &data);
data = 0x03;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT, port_number + 1, &data);
data = 0x00;
send_mos_cmd(port->serial, MOS_WRITE, MOS_MAX_PORT, port_number + 1, &data);
*/
data = 0x00;
send_mos_cmd(serial, MOS_READ, MOS_MAX_PORT, 0x08, &data);
data = data | (port->number - port->serial->minor + 1);
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT, 0x08, &data);
data = 0x83;
mos7720_port->shadowLCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x03, &data);
data = 0x0c;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x00, &data);
data = 0x00;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x01, &data);
data = 0x03;
mos7720_port->shadowLCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x03, &data);
data = 0x0c;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x01, &data);
data = 0x0c;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x01, &data);
//Matrix
/* force low_latency on so that our tty_push actually forces *
* the data through,otherwise it is scheduled, and with *
* high data rates (like with OHCI) data can get lost. */
if (port->tty)
port->tty->low_latency = 1;
/* see if we've set up our endpoint info yet *
* (can't set it up in mos7720_startup as the *
* structures were not set up at that time.) */
if (!mos7720_serial->interrupt_started) {
dbg("Interrupt buffer NULL !!!");
/* not set up yet, so do it now */
mos7720_serial->interrupt_started = 1;
dbg("To Submit URB !!!");
/* set up our interrupt urb */
usb_fill_int_urb(port0->interrupt_in_urb, serial->dev,
usb_rcvintpipe(serial->dev,
port->interrupt_in_endpointAddress),
port0->interrupt_in_buffer,
port0->interrupt_in_urb->transfer_buffer_length,
mos7720_interrupt_callback, mos7720_port,
port0->interrupt_in_urb->interval);
/* start interrupt read for this mos7720 this interrupt *
* will continue as long as the mos7720 is connected */
dbg("Submit URB over !!!");
response = usb_submit_urb(port0->interrupt_in_urb, GFP_KERNEL);
if (response)
dev_err(&port->dev,
"%s - Error %d submitting control urb",
__FUNCTION__, response);
}
/* set up our bulk in urb */
usb_fill_bulk_urb(port->read_urb, serial->dev,
usb_rcvbulkpipe(serial->dev,
port->bulk_in_endpointAddress),
port->bulk_in_buffer,
port->read_urb->transfer_buffer_length,
mos7720_bulk_in_callback, mos7720_port);
response = usb_submit_urb(port->read_urb, GFP_KERNEL);
if (response)
dev_err(&port->dev,
"%s - Error %d submitting read urb", __FUNCTION__, response);
/* initialize our icount structure */
memset(&(mos7720_port->icount), 0x00, sizeof(mos7720_port->icount));
/* initialize our port settings */
mos7720_port->shadowMCR = UART_MCR_OUT2; /* Must set to enable ints! */
/* send a open port command */
mos7720_port->open = 1;
return 0;
}
/*
* mos7720_chars_in_buffer
* this function is called by the tty driver when it wants to know how many
* bytes of data we currently have outstanding in the port (data that has
* been written, but hasn't made it out the port yet)
* If successful, we return the number of bytes left to be written in the
* system,
* Otherwise we return a negative error number.
*/
static int mos7720_chars_in_buffer(struct usb_serial_port *port)
{
int i;
int chars = 0;
struct moschip_port *mos7720_port;
dbg("%s:entering ...........", __FUNCTION__);
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL) {
dbg("%s:leaving ...........", __FUNCTION__);
return -ENODEV;
}
for (i = 0; i < NUM_URBS; ++i) {
if (mos7720_port->write_urb_pool[i]->status == -EINPROGRESS)
chars += URB_TRANSFER_BUFFER_SIZE;
}
dbg("%s - returns %d", __FUNCTION__, chars);
return chars;
}
static void mos7720_close(struct usb_serial_port *port, struct file *filp)
{
struct usb_serial *serial;
struct moschip_port *mos7720_port;
char data;
int j;
dbg("mos7720_close:entering...");
serial = port->serial;
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL)
return;
for (j = 0; j < NUM_URBS; ++j)
usb_kill_urb(mos7720_port->write_urb_pool[j]);
/* Freeing Write URBs */
for (j = 0; j < NUM_URBS; ++j) {
if (mos7720_port->write_urb_pool[j]) {
kfree(mos7720_port->write_urb_pool[j]->transfer_buffer);
usb_free_urb(mos7720_port->write_urb_pool[j]);
}
}
/* While closing port, shutdown all bulk read, write *
* and interrupt read if they exists */
if (serial->dev) {
dbg("Shutdown bulk write");
usb_kill_urb(port->write_urb);
dbg("Shutdown bulk read");
usb_kill_urb(port->read_urb);
}
data = 0x00;
send_mos_cmd(serial, MOS_WRITE, port->number - port->serial->minor,
0x04, &data);
data = 0x00;
send_mos_cmd(serial, MOS_WRITE, port->number - port->serial->minor,
0x01, &data);
mos7720_port->open = 0;
dbg("Leaving %s", __FUNCTION__);
}
static void mos7720_break(struct usb_serial_port *port, int break_state)
{
unsigned char data;
struct usb_serial *serial;
struct moschip_port *mos7720_port;
dbg("Entering %s", __FUNCTION__);
serial = port->serial;
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL)
return;
if (break_state == -1)
data = mos7720_port->shadowLCR | UART_LCR_SBC;
else
data = mos7720_port->shadowLCR & ~UART_LCR_SBC;
mos7720_port->shadowLCR = data;
send_mos_cmd(serial, MOS_WRITE, port->number - port->serial->minor,
0x03, &data);
return;
}
/*
* mos7720_write_room
* this function is called by the tty driver when it wants to know how many
* bytes of data we can accept for a specific port.
* If successful, we return the amount of room that we have for this port
* Otherwise we return a negative error number.
*/
static int mos7720_write_room(struct usb_serial_port *port)
{
struct moschip_port *mos7720_port;
int room = 0;
int i;
dbg("%s:entering ...........", __FUNCTION__);
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL) {
dbg("%s:leaving ...........", __FUNCTION__);
return -ENODEV;
}
for (i = 0; i < NUM_URBS; ++i) {
if (mos7720_port->write_urb_pool[i]->status != -EINPROGRESS)
room += URB_TRANSFER_BUFFER_SIZE;
}
dbg("%s - returns %d", __FUNCTION__, room);
return room;
}
static int mos7720_write(struct usb_serial_port *port,
const unsigned char *data, int count)
{
int status;
int i;
int bytes_sent = 0;
int transfer_size;
struct moschip_port *mos7720_port;
struct usb_serial *serial;
struct urb *urb;
const unsigned char *current_position = data;
dbg("%s:entering ...........", __FUNCTION__);
serial = port->serial;
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL) {
dbg("mos7720_port is NULL");
return -ENODEV;
}
/* try to find a free urb in the list */
urb = NULL;
for (i = 0; i < NUM_URBS; ++i) {
if (mos7720_port->write_urb_pool[i]->status != -EINPROGRESS) {
urb = mos7720_port->write_urb_pool[i];
dbg("URB:%d",i);
break;
}
}
if (urb == NULL) {
dbg("%s - no more free urbs", __FUNCTION__);
goto exit;
}
if (urb->transfer_buffer == NULL) {
urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
GFP_KERNEL);
if (urb->transfer_buffer == NULL) {
err("%s no more kernel memory...", __FUNCTION__);
goto exit;
}
}
transfer_size = min (count, URB_TRANSFER_BUFFER_SIZE);
memcpy(urb->transfer_buffer, current_position, transfer_size);
usb_serial_debug_data(debug, &port->dev, __FUNCTION__, transfer_size,
urb->transfer_buffer);
/* fill urb with data and submit */
usb_fill_bulk_urb(urb, serial->dev,
usb_sndbulkpipe(serial->dev,
port->bulk_out_endpointAddress),
urb->transfer_buffer, transfer_size,
mos7720_bulk_out_data_callback, mos7720_port);
/* send it down the pipe */
status = usb_submit_urb(urb,GFP_ATOMIC);
if (status) {
err("%s - usb_submit_urb(write bulk) failed with status = %d",
__FUNCTION__, status);
bytes_sent = status;
goto exit;
}
bytes_sent = transfer_size;
exit:
return bytes_sent;
}
static void mos7720_throttle(struct usb_serial_port *port)
{
struct moschip_port *mos7720_port;
struct tty_struct *tty;
int status;
dbg("%s- port %d\n", __FUNCTION__, port->number);
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL)
return;
if (!mos7720_port->open) {
dbg("port not opened");
return;
}
dbg("%s: Entering ..........", __FUNCTION__);
tty = port->tty;
if (!tty) {
dbg("%s - no tty available", __FUNCTION__);
return;
}
/* if we are implementing XON/XOFF, send the stop character */
if (I_IXOFF(tty)) {
unsigned char stop_char = STOP_CHAR(tty);
status = mos7720_write(port, &stop_char, 1);
if (status <= 0)
return;
}
/* if we are implementing RTS/CTS, toggle that line */
if (tty->termios->c_cflag & CRTSCTS) {
mos7720_port->shadowMCR &= ~UART_MCR_RTS;
status = send_mos_cmd(port->serial, MOS_WRITE,
port->number - port->serial->minor,
UART_MCR, &mos7720_port->shadowMCR);
if (status != 0)
return;
}
}
static void mos7720_unthrottle(struct usb_serial_port *port)
{
struct tty_struct *tty;
int status;
struct moschip_port *mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL)
return;
if (!mos7720_port->open) {
dbg("%s - port not opened", __FUNCTION__);
return;
}
dbg("%s: Entering ..........", __FUNCTION__);
tty = port->tty;
if (!tty) {
dbg("%s - no tty available", __FUNCTION__);
return;
}
/* if we are implementing XON/XOFF, send the start character */
if (I_IXOFF(tty)) {
unsigned char start_char = START_CHAR(tty);
status = mos7720_write(port, &start_char, 1);
if (status <= 0)
return;
}
/* if we are implementing RTS/CTS, toggle that line */
if (tty->termios->c_cflag & CRTSCTS) {
mos7720_port->shadowMCR |= UART_MCR_RTS;
status = send_mos_cmd(port->serial, MOS_WRITE,
port->number - port->serial->minor,
UART_MCR, &mos7720_port->shadowMCR);
if (status != 0)
return;
}
}
static int set_higher_rates(struct moschip_port *mos7720_port,
unsigned int baud)
{
unsigned char data;
struct usb_serial_port *port;
struct usb_serial *serial;
int port_number;
if (mos7720_port == NULL)
return -EINVAL;
port = mos7720_port->port;
serial = port->serial;
/***********************************************
* Init Sequence for higher rates
***********************************************/
dbg("Sending Setting Commands ..........");
port_number = port->number - port->serial->minor;
data = 0x000;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x01, &data);
data = 0x000;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x02, &data);
data = 0x0CF;
send_mos_cmd(serial, MOS_WRITE, port->number, 0x02, &data);
data = 0x00b;
mos7720_port->shadowMCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x04, &data);
data = 0x00b;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x04, &data);
data = 0x000;
send_mos_cmd(serial, MOS_READ, MOS_MAX_PORT, 0x08, &data);
data = 0x000;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT, 0x08, &data);
/***********************************************
* Set for higher rates *
***********************************************/
data = baud * 0x10;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT, port_number + 1,&data);
data = 0x003;
send_mos_cmd(serial, MOS_READ, MOS_MAX_PORT, 0x08, &data);
data = 0x003;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT, 0x08, &data);
data = 0x02b;
mos7720_port->shadowMCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x04, &data);
data = 0x02b;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x04, &data);
/***********************************************
* Set DLL/DLM
***********************************************/
data = mos7720_port->shadowLCR | UART_LCR_DLAB;
mos7720_port->shadowLCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x03, &data);
data = 0x001; /* DLL */
send_mos_cmd(serial, MOS_WRITE, port_number, 0x00, &data);
data = 0x000; /* DLM */
send_mos_cmd(serial, MOS_WRITE, port_number, 0x01, &data);
data = mos7720_port->shadowLCR & ~UART_LCR_DLAB;
mos7720_port->shadowLCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x03, &data);
return 0;
}
/* baud rate information */
struct divisor_table_entry
{
__u32 baudrate;
__u16 divisor;
};
/* Define table of divisors for moschip 7720 hardware *
* These assume a 3.6864MHz crystal, the standard /16, and *
* MCR.7 = 0. */
static struct divisor_table_entry divisor_table[] = {
{ 50, 2304},
{ 110, 1047}, /* 2094.545455 => 230450 => .0217 % over */
{ 134, 857}, /* 1713.011152 => 230398.5 => .00065% under */
{ 150, 768},
{ 300, 384},
{ 600, 192},
{ 1200, 96},
{ 1800, 64},
{ 2400, 48},
{ 4800, 24},
{ 7200, 16},
{ 9600, 12},
{ 19200, 6},
{ 38400, 3},
{ 57600, 2},
{ 115200, 1},
};
/*****************************************************************************
* calc_baud_rate_divisor
* this function calculates the proper baud rate divisor for the specified
* baud rate.
*****************************************************************************/
static int calc_baud_rate_divisor(int baudrate, int *divisor)
{
int i;
__u16 custom;
__u16 round1;
__u16 round;
dbg("%s - %d", __FUNCTION__, baudrate);
for (i = 0; i < ARRAY_SIZE(divisor_table); i++) {
if (divisor_table[i].baudrate == baudrate) {
*divisor = divisor_table[i].divisor;
return 0;
}
}
/* After trying for all the standard baud rates *
* Try calculating the divisor for this baud rate */
if (baudrate > 75 && baudrate < 230400) {
/* get the divisor */
custom = (__u16)(230400L / baudrate);
/* Check for round off */
round1 = (__u16)(2304000L / baudrate);
round = (__u16)(round1 - (custom * 10));
if (round > 4)
custom++;
*divisor = custom;
dbg("Baud %d = %d",baudrate, custom);
return 0;
}
dbg("Baud calculation Failed...");
return -EINVAL;
}
/*
* send_cmd_write_baud_rate
* this function sends the proper command to change the baud rate of the
* specified port.
*/
static int send_cmd_write_baud_rate(struct moschip_port *mos7720_port,
int baudrate)
{
struct usb_serial_port *port;
struct usb_serial *serial;
int divisor;
int status;
unsigned char data;
unsigned char number;
if (mos7720_port == NULL)
return -1;
port = mos7720_port->port;
serial = port->serial;
dbg("%s: Entering ..........", __FUNCTION__);
number = port->number - port->serial->minor;
dbg("%s - port = %d, baud = %d", __FUNCTION__, port->number, baudrate);
/* Calculate the Divisor */
status = calc_baud_rate_divisor(baudrate, &divisor);
if (status) {
err("%s - bad baud rate", __FUNCTION__);
return status;
}
/* Enable access to divisor latch */
data = mos7720_port->shadowLCR | UART_LCR_DLAB;
mos7720_port->shadowLCR = data;
send_mos_cmd(serial, MOS_WRITE, number, UART_LCR, &data);
/* Write the divisor */
data = ((unsigned char)(divisor & 0xff));
send_mos_cmd(serial, MOS_WRITE, number, 0x00, &data);
data = ((unsigned char)((divisor & 0xff00) >> 8));
send_mos_cmd(serial, MOS_WRITE, number, 0x01, &data);
/* Disable access to divisor latch */
data = mos7720_port->shadowLCR & ~UART_LCR_DLAB;
mos7720_port->shadowLCR = data;
send_mos_cmd(serial, MOS_WRITE, number, 0x03, &data);
return status;
}
/*
* change_port_settings
* This routine is called to set the UART on the device to match
* the specified new settings.
*/
static void change_port_settings(struct moschip_port *mos7720_port,
struct ktermios *old_termios)
{
struct usb_serial_port *port;
struct usb_serial *serial;
struct tty_struct *tty;
int baud;
unsigned cflag;
unsigned iflag;
__u8 mask = 0xff;
__u8 lData;
__u8 lParity;
__u8 lStop;
int status;
int port_number;
char data;
if (mos7720_port == NULL)
return ;
port = mos7720_port->port;
serial = port->serial;
port_number = port->number - port->serial->minor;
dbg("%s - port %d", __FUNCTION__, port->number);
if (!mos7720_port->open) {
dbg("%s - port not opened", __FUNCTION__);
return;
}
tty = mos7720_port->port->tty;
if ((!tty) || (!tty->termios)) {
dbg("%s - no tty structures", __FUNCTION__);
return;
}
dbg("%s: Entering ..........", __FUNCTION__);
lData = UART_LCR_WLEN8;
lStop = 0x00; /* 1 stop bit */
lParity = 0x00; /* No parity */
cflag = tty->termios->c_cflag;
iflag = tty->termios->c_iflag;
/* Change the number of bits */
switch (cflag & CSIZE) {
case CS5:
lData = UART_LCR_WLEN5;
mask = 0x1f;
break;
case CS6:
lData = UART_LCR_WLEN6;
mask = 0x3f;
break;
case CS7:
lData = UART_LCR_WLEN7;
mask = 0x7f;
break;
default:
case CS8:
lData = UART_LCR_WLEN8;
break;
}
/* Change the Parity bit */
if (cflag & PARENB) {
if (cflag & PARODD) {
lParity = UART_LCR_PARITY;
dbg("%s - parity = odd", __FUNCTION__);
} else {
lParity = (UART_LCR_EPAR | UART_LCR_PARITY);
dbg("%s - parity = even", __FUNCTION__);
}
} else {
dbg("%s - parity = none", __FUNCTION__);
}
if (cflag & CMSPAR)
lParity = lParity | 0x20;
/* Change the Stop bit */
if (cflag & CSTOPB) {
lStop = UART_LCR_STOP;
dbg("%s - stop bits = 2", __FUNCTION__);
} else {
lStop = 0x00;
dbg("%s - stop bits = 1", __FUNCTION__);
}
#define LCR_BITS_MASK 0x03 /* Mask for bits/char field */
#define LCR_STOP_MASK 0x04 /* Mask for stop bits field */
#define LCR_PAR_MASK 0x38 /* Mask for parity field */
/* Update the LCR with the correct value */
mos7720_port->shadowLCR &= ~(LCR_BITS_MASK | LCR_STOP_MASK | LCR_PAR_MASK);
mos7720_port->shadowLCR |= (lData | lParity | lStop);
/* Disable Interrupts */
data = 0x00;
send_mos_cmd(serial,MOS_WRITE,port->number - port->serial->minor, UART_IER, &data);
data = 0x00;
send_mos_cmd(serial, MOS_WRITE, port_number, UART_FCR, &data);
data = 0xcf;
send_mos_cmd(serial, MOS_WRITE, port_number, UART_FCR, &data);
/* Send the updated LCR value to the mos7720 */
data = mos7720_port->shadowLCR;
send_mos_cmd(serial, MOS_WRITE, port_number, UART_LCR, &data);
data = 0x00b;
mos7720_port->shadowMCR = data;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x04, &data);
data = 0x00b;
send_mos_cmd(serial, MOS_WRITE, port_number, 0x04, &data);
/* set up the MCR register and send it to the mos7720 */
mos7720_port->shadowMCR = UART_MCR_OUT2;
if (cflag & CBAUD)
mos7720_port->shadowMCR |= (UART_MCR_DTR | UART_MCR_RTS);
if (cflag & CRTSCTS) {
mos7720_port->shadowMCR |= (UART_MCR_XONANY);
/* To set hardware flow control to the specified *
* serial port, in SP1/2_CONTROL_REG */
if (port->number) {
data = 0x001;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT,
0x08, &data);
} else {
data = 0x002;
send_mos_cmd(serial, MOS_WRITE, MOS_MAX_PORT,
0x08, &data);
}
} else {
mos7720_port->shadowMCR &= ~(UART_MCR_XONANY);
}
data = mos7720_port->shadowMCR;
send_mos_cmd(serial, MOS_WRITE, port_number, UART_MCR, &data);
/* Determine divisor based on baud rate */
baud = tty_get_baud_rate(tty);
if (!baud) {
/* pick a default, any default... */
dbg("Picked default baud...");
baud = 9600;
}
if (baud >= 230400) {
set_higher_rates(mos7720_port, baud);
/* Enable Interrupts */
data = 0x0c;
send_mos_cmd(serial, MOS_WRITE, port_number, UART_IER, &data);
return;
}
dbg("%s - baud rate = %d", __FUNCTION__, baud);
status = send_cmd_write_baud_rate(mos7720_port, baud);
/* Enable Interrupts */
data = 0x0c;
send_mos_cmd(serial, MOS_WRITE, port_number, UART_IER, &data);
if (port->read_urb->status != -EINPROGRESS) {
port->read_urb->dev = serial->dev;
status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
if (status)
dbg("usb_submit_urb(read bulk) failed, status = %d",
status);
}
return;
}
/*
* mos7720_set_termios
* this function is called by the tty driver when it wants to change the
* termios structure.
*/
static void mos7720_set_termios(struct usb_serial_port *port,
struct ktermios *old_termios)
{
int status;
unsigned int cflag;
struct usb_serial *serial;
struct moschip_port *mos7720_port;
struct tty_struct *tty;
serial = port->serial;
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL)
return;
tty = port->tty;
if (!port->tty || !port->tty->termios) {
dbg("%s - no tty or termios", __FUNCTION__);
return;
}
if (!mos7720_port->open) {
dbg("%s - port not opened", __FUNCTION__);
return;
}
dbg("%s\n","setting termios - ASPIRE");
cflag = tty->termios->c_cflag;
if (!cflag) {
printk("%s %s\n",__FUNCTION__,"cflag is NULL");
return;
}
/* check that they really want us to change something */
if (old_termios) {
if ((cflag == old_termios->c_cflag) &&
(RELEVANT_IFLAG(tty->termios->c_iflag) ==
RELEVANT_IFLAG(old_termios->c_iflag))) {
dbg("Nothing to change");
return;
}
}
dbg("%s - clfag %08x iflag %08x", __FUNCTION__,
tty->termios->c_cflag,
RELEVANT_IFLAG(tty->termios->c_iflag));
if (old_termios)
dbg("%s - old clfag %08x old iflag %08x", __FUNCTION__,
old_termios->c_cflag,
RELEVANT_IFLAG(old_termios->c_iflag));
dbg("%s - port %d", __FUNCTION__, port->number);
/* change the port settings to the new ones specified */
change_port_settings(mos7720_port, old_termios);
if(!port->read_urb) {
dbg("%s","URB KILLED !!!!!\n");
return;
}
if(port->read_urb->status != -EINPROGRESS) {
port->read_urb->dev = serial->dev;
status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
if (status)
dbg("usb_submit_urb(read bulk) failed, status = %d",
status);
}
return;
}
/*
* get_lsr_info - get line status register info
*
* Purpose: Let user call ioctl() to get info when the UART physically
* is emptied. On bus types like RS485, the transmitter must
* release the bus after transmitting. This must be done when
* the transmit shift register is empty, not be done when the
* transmit holding register is empty. This functionality
* allows an RS485 driver to be written in user space.
*/
static int get_lsr_info(struct moschip_port *mos7720_port,
unsigned int __user *value)
{
int count;
unsigned int result = 0;
count = mos7720_chars_in_buffer(mos7720_port->port);
if (count == 0) {
dbg("%s -- Empty", __FUNCTION__);
result = TIOCSER_TEMT;
}
if (copy_to_user(value, &result, sizeof(int)))
return -EFAULT;
return 0;
}
/*
* get_number_bytes_avail - get number of bytes available
*
* Purpose: Let user call ioctl to get the count of number of bytes available.
*/
static int get_number_bytes_avail(struct moschip_port *mos7720_port,
unsigned int __user *value)
{
unsigned int result = 0;
struct tty_struct *tty = mos7720_port->port->tty;
if (!tty)
return -ENOIOCTLCMD;
result = tty->read_cnt;
dbg("%s(%d) = %d", __FUNCTION__, mos7720_port->port->number, result);
if (copy_to_user(value, &result, sizeof(int)))
return -EFAULT;
return -ENOIOCTLCMD;
}
static int set_modem_info(struct moschip_port *mos7720_port, unsigned int cmd,
unsigned int __user *value)
{
unsigned int mcr ;
unsigned int arg;
unsigned char data;
struct usb_serial_port *port;
if (mos7720_port == NULL)
return -1;
port = (struct usb_serial_port*)mos7720_port->port;
mcr = mos7720_port->shadowMCR;
if (copy_from_user(&arg, value, sizeof(int)))
return -EFAULT;
switch (cmd) {
case TIOCMBIS:
if (arg & TIOCM_RTS)
mcr |= UART_MCR_RTS;
if (arg & TIOCM_DTR)
mcr |= UART_MCR_RTS;
if (arg & TIOCM_LOOP)
mcr |= UART_MCR_LOOP;
break;
case TIOCMBIC:
if (arg & TIOCM_RTS)
mcr &= ~UART_MCR_RTS;
if (arg & TIOCM_DTR)
mcr &= ~UART_MCR_RTS;
if (arg & TIOCM_LOOP)
mcr &= ~UART_MCR_LOOP;
break;
case TIOCMSET:
/* turn off the RTS and DTR and LOOPBACK
* and then only turn on what was asked to */
mcr &= ~(UART_MCR_RTS | UART_MCR_DTR | UART_MCR_LOOP);
mcr |= ((arg & TIOCM_RTS) ? UART_MCR_RTS : 0);
mcr |= ((arg & TIOCM_DTR) ? UART_MCR_DTR : 0);
mcr |= ((arg & TIOCM_LOOP) ? UART_MCR_LOOP : 0);
break;
}
mos7720_port->shadowMCR = mcr;
data = mos7720_port->shadowMCR;
send_mos_cmd(port->serial, MOS_WRITE,
port->number - port->serial->minor, UART_MCR, &data);
return 0;
}
static int get_modem_info(struct moschip_port *mos7720_port,
unsigned int __user *value)
{
unsigned int result = 0;
unsigned int msr = mos7720_port->shadowMSR;
unsigned int mcr = mos7720_port->shadowMCR;
result = ((mcr & UART_MCR_DTR) ? TIOCM_DTR: 0) /* 0x002 */
| ((mcr & UART_MCR_RTS) ? TIOCM_RTS: 0) /* 0x004 */
| ((msr & UART_MSR_CTS) ? TIOCM_CTS: 0) /* 0x020 */
| ((msr & UART_MSR_DCD) ? TIOCM_CAR: 0) /* 0x040 */
| ((msr & UART_MSR_RI) ? TIOCM_RI: 0) /* 0x080 */
| ((msr & UART_MSR_DSR) ? TIOCM_DSR: 0); /* 0x100 */
dbg("%s -- %x", __FUNCTION__, result);
if (copy_to_user(value, &result, sizeof(int)))
return -EFAULT;
return 0;
}
static int get_serial_info(struct moschip_port *mos7720_port,
struct serial_struct __user *retinfo)
{
struct serial_struct tmp;
if (!retinfo)
return -EFAULT;
memset(&tmp, 0, sizeof(tmp));
tmp.type = PORT_16550A;
tmp.line = mos7720_port->port->serial->minor;
tmp.port = mos7720_port->port->number;
tmp.irq = 0;
tmp.flags = ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
tmp.xmit_fifo_size = NUM_URBS * URB_TRANSFER_BUFFER_SIZE;
tmp.baud_base = 9600;
tmp.close_delay = 5*HZ;
tmp.closing_wait = 30*HZ;
if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
return -EFAULT;
return 0;
}
static int mos7720_ioctl(struct usb_serial_port *port, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct moschip_port *mos7720_port;
struct async_icount cnow;
struct async_icount cprev;
struct serial_icounter_struct icount;
mos7720_port = usb_get_serial_port_data(port);
if (mos7720_port == NULL)
return -ENODEV;
dbg("%s - port %d, cmd = 0x%x", __FUNCTION__, port->number, cmd);
switch (cmd) {
case TIOCINQ:
/* return number of bytes available */
dbg("%s (%d) TIOCINQ", __FUNCTION__, port->number);
return get_number_bytes_avail(mos7720_port,
(unsigned int __user *)arg);
break;
case TIOCSERGETLSR:
dbg("%s (%d) TIOCSERGETLSR", __FUNCTION__, port->number);
return get_lsr_info(mos7720_port, (unsigned int __user *)arg);
return 0;
case TIOCMBIS:
case TIOCMBIC:
case TIOCMSET:
dbg("%s (%d) TIOCMSET/TIOCMBIC/TIOCMSET", __FUNCTION__,
port->number);
return set_modem_info(mos7720_port, cmd,
(unsigned int __user *)arg);
case TIOCMGET:
dbg("%s (%d) TIOCMGET", __FUNCTION__, port->number);
return get_modem_info(mos7720_port,
(unsigned int __user *)arg);
case TIOCGSERIAL:
dbg("%s (%d) TIOCGSERIAL", __FUNCTION__, port->number);
return get_serial_info(mos7720_port,
(struct serial_struct __user *)arg);
case TIOCSSERIAL:
dbg("%s (%d) TIOCSSERIAL", __FUNCTION__, port->number);
break;
case TIOCMIWAIT:
dbg("%s (%d) TIOCMIWAIT", __FUNCTION__, port->number);
cprev = mos7720_port->icount;
while (1) {
if (signal_pending(current))
return -ERESTARTSYS;
cnow = mos7720_port->icount;
if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
return -EIO; /* no change => error */
if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
((arg & TIOCM_CTS) && (cnow.cts != cprev.cts)) ) {
return 0;
}
cprev = cnow;
}
/* NOTREACHED */
break;
case TIOCGICOUNT:
cnow = mos7720_port->icount;
icount.cts = cnow.cts;
icount.dsr = cnow.dsr;
icount.rng = cnow.rng;
icount.dcd = cnow.dcd;
icount.rx = cnow.rx;
icount.tx = cnow.tx;
icount.frame = cnow.frame;
icount.overrun = cnow.overrun;
icount.parity = cnow.parity;
icount.brk = cnow.brk;
icount.buf_overrun = cnow.buf_overrun;
dbg("%s (%d) TIOCGICOUNT RX=%d, TX=%d", __FUNCTION__,
port->number, icount.rx, icount.tx );
if (copy_to_user((void __user *)arg, &icount, sizeof(icount)))
return -EFAULT;
return 0;
}
return -ENOIOCTLCMD;
}
static int mos7720_startup(struct usb_serial *serial)
{
struct moschip_serial *mos7720_serial;
struct moschip_port *mos7720_port;
struct usb_device *dev;
int i;
char data;
dbg("%s: Entering ..........", __FUNCTION__);
if (!serial) {
dbg("Invalid Handler");
return -ENODEV;
}
dev = serial->dev;
/* create our private serial structure */
mos7720_serial = kzalloc(sizeof(struct moschip_serial), GFP_KERNEL);
if (mos7720_serial == NULL) {
err("%s - Out of memory", __FUNCTION__);
return -ENOMEM;
}
usb_set_serial_data(serial, mos7720_serial);
/* we set up the pointers to the endpoints in the mos7720_open *
* function, as the structures aren't created yet. */
/* set up port private structures */
for (i = 0; i < serial->num_ports; ++i) {
mos7720_port = kzalloc(sizeof(struct moschip_port), GFP_KERNEL);
if (mos7720_port == NULL) {
err("%s - Out of memory", __FUNCTION__);
usb_set_serial_data(serial, NULL);
kfree(mos7720_serial);
return -ENOMEM;
}
/* Initialize all port interrupt end point to port 0 int
* endpoint. Our device has only one interrupt endpoint
* comman to all ports */
serial->port[i]->interrupt_in_endpointAddress = serial->port[0]->interrupt_in_endpointAddress;
mos7720_port->port = serial->port[i];
usb_set_serial_port_data(serial->port[i], mos7720_port);
dbg("port number is %d", serial->port[i]->number);
dbg("serial number is %d", serial->minor);
}
/* setting configuration feature to one */
usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
(__u8)0x03, 0x00,0x01,0x00, NULL, 0x00, 5*HZ);
send_mos_cmd(serial,MOS_READ,0x00, UART_LSR, &data); // LSR For Port 1
dbg("LSR:%x",data);
send_mos_cmd(serial,MOS_READ,0x01, UART_LSR, &data); // LSR For Port 2
dbg("LSR:%x",data);
return 0;
}
static void mos7720_shutdown(struct usb_serial *serial)
{
int i;
/* free private structure allocated for serial port */
for (i=0; i < serial->num_ports; ++i) {
kfree(usb_get_serial_port_data(serial->port[i]));
usb_set_serial_port_data(serial->port[i], NULL);
}
/* free private structure allocated for serial device */
kfree(usb_get_serial_data(serial));
usb_set_serial_data(serial, NULL);
}
static struct usb_driver usb_driver = {
.name = "moschip7720",
.probe = usb_serial_probe,
.disconnect = usb_serial_disconnect,
.id_table = moschip_port_id_table,
.no_dynamic_id = 1,
};
static struct usb_serial_driver moschip7720_2port_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "moschip7720",
},
.description = "Moschip 2 port adapter",
.usb_driver = &usb_driver,
.id_table = moschip_port_id_table,
.num_interrupt_in = 1,
.num_bulk_in = 2,
.num_bulk_out = 2,
.num_ports = 2,
.open = mos7720_open,
.close = mos7720_close,
.throttle = mos7720_throttle,
.unthrottle = mos7720_unthrottle,
.attach = mos7720_startup,
.shutdown = mos7720_shutdown,
.ioctl = mos7720_ioctl,
.set_termios = mos7720_set_termios,
.write = mos7720_write,
.write_room = mos7720_write_room,
.chars_in_buffer = mos7720_chars_in_buffer,
.break_ctl = mos7720_break,
.read_bulk_callback = mos7720_bulk_in_callback,
.read_int_callback = mos7720_interrupt_callback,
};
static int __init moschip7720_init(void)
{
int retval;
dbg("%s: Entering ..........", __FUNCTION__);
/* Register with the usb serial */
retval = usb_serial_register(&moschip7720_2port_driver);
if (retval)
goto failed_port_device_register;
info(DRIVER_DESC " " DRIVER_VERSION);
/* Register with the usb */
retval = usb_register(&usb_driver);
if (retval)
goto failed_usb_register;
return 0;
failed_usb_register:
usb_serial_deregister(&moschip7720_2port_driver);
failed_port_device_register:
return retval;
}
static void __exit moschip7720_exit(void)
{
usb_deregister(&usb_driver);
usb_serial_deregister(&moschip7720_2port_driver);
}
module_init(moschip7720_init);
module_exit(moschip7720_exit);
/* Module information */
MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
MODULE_LICENSE("GPL");
module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");