/*
* USB Cypress M8 driver
*
* Copyright (C) 2004
* Lonnie Mendez (dignome@gmail.com)
* Copyright (C) 2003,2004
* Neil Whelchel (koyama@firstlight.net)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* See Documentation/usb/usb-serial.txt for more information on using this driver
*
* See http://geocities.com/i0xox0i for information on this driver and the
* earthmate usb device.
*
* Lonnie Mendez <dignome@gmail.com>
* 4-29-2005
* Fixed problem where setting or retreiving the serial config would fail with
* EPIPE. Removed CRTS toggling so the driver behaves more like other usbserial
* adapters. Issued new interval of 1ms instead of the default 10ms. As a
* result, transfer speed has been substantially increased. From avg. 850bps to
* avg. 3300bps. initial termios has also been modified. Cleaned up code and
* formatting issues so it is more readable. Replaced the C++ style comments.
*
* Lonnie Mendez <dignome@gmail.com>
* 12-15-2004
* Incorporated write buffering from pl2303 driver. Fixed bug with line
* handling so both lines are raised in cypress_open. (was dropping rts)
* Various code cleanups made as well along with other misc bug fixes.
*
* Lonnie Mendez <dignome@gmail.com>
* 04-10-2004
* Driver modified to support dynamic line settings. Various improvments
* and features.
*
* Neil Whelchel
* 10-2003
* Driver first released.
*
*/
/* Thanks to Neil Whelchel for writing the first cypress m8 implementation for linux. */
/* Thanks to cypress for providing references for the hid reports. */
/* Thanks to Jiang Zhang for providing links and for general help. */
/* Code originates and was built up from ftdi_sio, belkin, pl2303 and others. */
#include <linux/config.h>
#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/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/usb.h>
#include <linux/serial.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include "usb-serial.h"
#include "cypress_m8.h"
#ifdef CONFIG_USB_SERIAL_DEBUG
static int debug = 1;
#else
static int debug;
#endif
static int stats;
static int interval;
/*
* Version Information
*/
#define DRIVER_VERSION "v1.09"
#define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
#define DRIVER_DESC "Cypress USB to Serial Driver"
/* write buffer size defines */
#define CYPRESS_BUF_SIZE 1024
#define CYPRESS_CLOSING_WAIT (30*HZ)
static struct usb_device_id id_table_earthmate [] = {
{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
{ } /* Terminating entry */
};
static struct usb_device_id id_table_cyphidcomrs232 [] = {
{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
{ } /* Terminating entry */
};
static struct usb_device_id id_table_combined [] = {
{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
{ } /* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, id_table_combined);
static struct usb_driver cypress_driver = {
.name = "cypress",
.probe = usb_serial_probe,
.disconnect = usb_serial_disconnect,
.id_table = id_table_combined,
.no_dynamic_id = 1,
};
struct cypress_private {
spinlock_t lock; /* private lock */
int chiptype; /* identifier of device, for quirks/etc */
int bytes_in; /* used for statistics */
int bytes_out; /* used for statistics */
int cmd_count; /* used for statistics */
int cmd_ctrl; /* always set this to 1 before issuing a command */
struct cypress_buf *buf; /* write buffer */
int write_urb_in_use; /* write urb in use indicator */
int termios_initialized;
__u8 line_control; /* holds dtr / rts value */
__u8 current_status; /* received from last read - info on dsr,cts,cd,ri,etc */
__u8 current_config; /* stores the current configuration byte */
__u8 rx_flags; /* throttling - used from whiteheat/ftdi_sio */
int baud_rate; /* stores current baud rate in integer form */
int cbr_mask; /* stores current baud rate in masked form */
int isthrottled; /* if throttled, discard reads */
wait_queue_head_t delta_msr_wait; /* used for TIOCMIWAIT */
char prev_status, diff_status; /* used for TIOCMIWAIT */
/* we pass a pointer to this as the arguement sent to cypress_set_termios old_termios */
struct termios tmp_termios; /* stores the old termios settings */
};
/* write buffer structure */
struct cypress_buf {
unsigned int buf_size;
char *buf_buf;
char *buf_get;
char *buf_put;
};
/* function prototypes for the Cypress USB to serial device */
static int cypress_earthmate_startup (struct usb_serial *serial);
static int cypress_hidcom_startup (struct usb_serial *serial);
static void cypress_shutdown (struct usb_serial *serial);
static int cypress_open (struct usb_serial_port *port, struct file *filp);
static void cypress_close (struct usb_serial_port *port, struct file *filp);
static int cypress_write (struct usb_serial_port *port, const unsigned char *buf, int count);
static void cypress_send (struct usb_serial_port *port);
static int cypress_write_room (struct usb_serial_port *port);
static int cypress_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg);
static void cypress_set_termios (struct usb_serial_port *port, struct termios * old);
static int cypress_tiocmget (struct usb_serial_port *port, struct file *file);
static int cypress_tiocmset (struct usb_serial_port *port, struct file *file, unsigned int set, unsigned int clear);
static int cypress_chars_in_buffer (struct usb_serial_port *port);
static void cypress_throttle (struct usb_serial_port *port);
static void cypress_unthrottle (struct usb_serial_port *port);
static void cypress_read_int_callback (struct urb *urb, struct pt_regs *regs);
static void cypress_write_int_callback (struct urb *urb, struct pt_regs *regs);
/* baud helper functions */
static int mask_to_rate (unsigned mask);
static unsigned rate_to_mask (int rate);
/* write buffer functions */
static struct cypress_buf *cypress_buf_alloc(unsigned int size);
static void cypress_buf_free(struct cypress_buf *cb);
static void cypress_buf_clear(struct cypress_buf *cb);
static unsigned int cypress_buf_data_avail(struct cypress_buf *cb);
static unsigned int cypress_buf_space_avail(struct cypress_buf *cb);
static unsigned int cypress_buf_put(struct cypress_buf *cb, const char *buf, unsigned int count);
static unsigned int cypress_buf_get(struct cypress_buf *cb, char *buf, unsigned int count);
static struct usb_serial_driver cypress_earthmate_device = {
.driver = {
.owner = THIS_MODULE,
.name = "earthmate",
},
.description = "DeLorme Earthmate USB",
.id_table = id_table_earthmate,
.num_interrupt_in = 1,
.num_interrupt_out = 1,
.num_bulk_in = NUM_DONT_CARE,
.num_bulk_out = NUM_DONT_CARE,
.num_ports = 1,
.attach = cypress_earthmate_startup,
.shutdown = cypress_shutdown,
.open = cypress_open,
.close = cypress_close,
.write = cypress_write,
.write_room = cypress_write_room,
.ioctl = cypress_ioctl,
.set_termios = cypress_set_termios,
.tiocmget = cypress_tiocmget,
.tiocmset = cypress_tiocmset,
.chars_in_buffer = cypress_chars_in_buffer,
.throttle = cypress_throttle,
.unthrottle = cypress_unthrottle,
.read_int_callback = cypress_read_int_callback,
.write_int_callback = cypress_write_int_callback,
};
static struct usb_serial_driver cypress_hidcom_device = {
.driver = {
.owner = THIS_MODULE,
.name = "cyphidcom",
},
.description = "HID->COM RS232 Adapter",
.id_table = id_table_cyphidcomrs232,
.num_interrupt_in = 1,
.num_interrupt_out = 1,
.num_bulk_in = NUM_DONT_CARE,
.num_bulk_out = NUM_DONT_CARE,
.num_ports = 1,
.attach = cypress_hidcom_startup,
.shutdown = cypress_shutdown,
.open = cypress_open,
.close = cypress_close,
.write = cypress_write,
.write_room = cypress_write_room,
.ioctl = cypress_ioctl,
.set_termios = cypress_set_termios,
.tiocmget = cypress_tiocmget,
.tiocmset = cypress_tiocmset,
.chars_in_buffer = cypress_chars_in_buffer,
.throttle = cypress_throttle,
.unthrottle = cypress_unthrottle,
.read_int_callback = cypress_read_int_callback,
.write_int_callback = cypress_write_int_callback,
};
/*****************************************************************************
* Cypress serial helper functions
*****************************************************************************/
/* This function can either set or retrieve the current serial line settings */
static int cypress_serial_control (struct usb_serial_port *port, unsigned baud_mask, int data_bits, int stop_bits,
int parity_enable, int parity_type, int reset, int cypress_request_type)
{
int new_baudrate = 0, retval = 0, tries = 0;
struct cypress_private *priv;
__u8 feature_buffer[8];
unsigned long flags;
dbg("%s", __FUNCTION__);
priv = usb_get_serial_port_data(port);
switch(cypress_request_type) {
case CYPRESS_SET_CONFIG:
/*
* The general purpose firmware for the Cypress M8 allows for a maximum speed
* of 57600bps (I have no idea whether DeLorme chose to use the general purpose
* firmware or not), if you need to modify this speed setting for your own
* project please add your own chiptype and modify the code likewise. The
* Cypress HID->COM device will work successfully up to 115200bps (but the
* actual throughput is around 3kBps).
*/
if (baud_mask != priv->cbr_mask) {
dbg("%s - baud rate is changing", __FUNCTION__);
if ( priv->chiptype == CT_EARTHMATE ) {
/* 300 and 600 baud rates are supported under the generic firmware,
* but are not used with NMEA and SiRF protocols */
if ( (baud_mask == B300) || (baud_mask == B600) ) {
err("%s - failed setting baud rate, unsupported speed",
__FUNCTION__);
new_baudrate = priv->baud_rate;
} else if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) {
err("%s - failed setting baud rate, unsupported speed",
__FUNCTION__);
new_baudrate = priv->baud_rate;
}
} else if (priv->chiptype == CT_CYPHIDCOM) {
if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) {
err("%s - failed setting baud rate, unsupported speed",
__FUNCTION__);
new_baudrate = priv->baud_rate;
}
} else if (priv->chiptype == CT_GENERIC) {
if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) {
err("%s - failed setting baud rate, unsupported speed",
__FUNCTION__);
new_baudrate = priv->baud_rate;
}
} else {
info("%s - please define your chiptype", __FUNCTION__);
new_baudrate = priv->baud_rate;
}
} else { /* baud rate not changing, keep the old */
new_baudrate = priv->baud_rate;
}
dbg("%s - baud rate is being sent as %d", __FUNCTION__, new_baudrate);
memset(feature_buffer, 0, 8);
/* fill the feature_buffer with new configuration */
*((u_int32_t *)feature_buffer) = new_baudrate;
feature_buffer[4] |= data_bits; /* assign data bits in 2 bit space ( max 3 ) */
/* 1 bit gap */
feature_buffer[4] |= (stop_bits << 3); /* assign stop bits in 1 bit space */
feature_buffer[4] |= (parity_enable << 4); /* assign parity flag in 1 bit space */
feature_buffer[4] |= (parity_type << 5); /* assign parity type in 1 bit space */
/* 1 bit gap */
feature_buffer[4] |= (reset << 7); /* assign reset at end of byte, 1 bit space */
dbg("%s - device is being sent this feature report:", __FUNCTION__);
dbg("%s - %02X - %02X - %02X - %02X - %02X", __FUNCTION__, feature_buffer[0], feature_buffer[1],
feature_buffer[2], feature_buffer[3], feature_buffer[4]);
do {
retval = usb_control_msg (port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0),
HID_REQ_SET_REPORT, USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
0x0300, 0, feature_buffer, 8, 500);
if (tries++ >= 3)
break;
if (retval == EPIPE)
usb_clear_halt(port->serial->dev, 0x00);
} while (retval != 8 && retval != ENODEV);
if (retval != 8)
err("%s - failed sending serial line settings - %d", __FUNCTION__, retval);
else {
spin_lock_irqsave(&priv->lock, flags);
priv->baud_rate = new_baudrate;
priv->cbr_mask = baud_mask;
priv->current_config = feature_buffer[4];
spin_unlock_irqrestore(&priv->lock, flags);
}
break;
case CYPRESS_GET_CONFIG:
dbg("%s - retreiving serial line settings", __FUNCTION__);
/* set initial values in feature buffer */
memset(feature_buffer, 0, 8);
do {
retval = usb_control_msg (port->serial->dev, usb_rcvctrlpipe(port->serial->dev, 0),
HID_REQ_GET_REPORT, USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
0x0300, 0, feature_buffer, 8, 500);
if (tries++ >= 3)
break;
if (retval == EPIPE)
usb_clear_halt(port->serial->dev, 0x00);
} while (retval != 5 && retval != ENODEV);
if (retval != 5) {
err("%s - failed to retrieve serial line settings - %d", __FUNCTION__, retval);
return retval;
} else {
spin_lock_irqsave(&priv->lock, flags);
/* store the config in one byte, and later use bit masks to check values */
priv->current_config = feature_buffer[4];
priv->baud_rate = *((u_int32_t *)feature_buffer);
if ( (priv->cbr_mask = rate_to_mask(priv->baud_rate)) == 0x40)
dbg("%s - failed setting the baud mask (not defined)", __FUNCTION__);
spin_unlock_irqrestore(&priv->lock, flags);
}
}
spin_lock_irqsave(&priv->lock, flags);
++priv->cmd_count;
spin_unlock_irqrestore(&priv->lock, flags);
return retval;
} /* cypress_serial_control */
/* given a baud mask, it will return integer baud on success */
static int mask_to_rate (unsigned mask)
{
int rate;
switch (mask) {
case B0: rate = 0; break;
case B300: rate = 300; break;
case B600: rate = 600; break;
case B1200: rate = 1200; break;
case B2400: rate = 2400; break;
case B4800: rate = 4800; break;
case B9600: rate = 9600; break;
case B19200: rate = 19200; break;
case B38400: rate = 38400; break;
case B57600: rate = 57600; break;
case B115200: rate = 115200; break;
default: rate = -1;
}
return rate;
}
static unsigned rate_to_mask (int rate)
{
unsigned mask;
switch (rate) {
case 0: mask = B0; break;
case 300: mask = B300; break;
case 600: mask = B600; break;
case 1200: mask = B1200; break;
case 2400: mask = B2400; break;
case 4800: mask = B4800; break;
case 9600: mask = B9600; break;
case 19200: mask = B19200; break;
case 38400: mask = B38400; break;
case 57600: mask = B57600; break;
case 115200: mask = B115200; break;
default: mask = 0x40;
}
return mask;
}
/*****************************************************************************
* Cypress serial driver functions
*****************************************************************************/
static int generic_startup (struct usb_serial *serial)
{
struct cypress_private *priv;
dbg("%s - port %d", __FUNCTION__, serial->port[0]->number);
priv = kzalloc(sizeof (struct cypress_private), GFP_KERNEL);
if (!priv)
return -ENOMEM;
spin_lock_init(&priv->lock);
priv->buf = cypress_buf_alloc(CYPRESS_BUF_SIZE);
if (priv->buf == NULL) {
kfree(priv);
return -ENOMEM;
}
init_waitqueue_head(&priv->delta_msr_wait);
usb_reset_configuration (serial->dev);
interval = 1;
priv->cmd_ctrl = 0;
priv->line_control = 0;
priv->termios_initialized = 0;
priv->rx_flags = 0;
priv->cbr_mask = B300;
usb_set_serial_port_data(serial->port[0], priv);
return 0;
}
static int cypress_earthmate_startup (struct usb_serial *serial)
{
struct cypress_private *priv;
dbg("%s", __FUNCTION__);
if (generic_startup(serial)) {
dbg("%s - Failed setting up port %d", __FUNCTION__,
serial->port[0]->number);
return 1;
}
priv = usb_get_serial_port_data(serial->port[0]);
priv->chiptype = CT_EARTHMATE;
return 0;
} /* cypress_earthmate_startup */
static int cypress_hidcom_startup (struct usb_serial *serial)
{
struct cypress_private *priv;
dbg("%s", __FUNCTION__);
if (generic_startup(serial)) {
dbg("%s - Failed setting up port %d", __FUNCTION__,
serial->port[0]->number);
return 1;
}
priv = usb_get_serial_port_data(serial->port[0]);
priv->chiptype = CT_CYPHIDCOM;
return 0;
} /* cypress_hidcom_startup */
static void cypress_shutdown (struct usb_serial *serial)
{
struct cypress_private *priv;
dbg ("%s - port %d", __FUNCTION__, serial->port[0]->number);
/* all open ports are closed at this point */
priv = usb_get_serial_port_data(serial->port[0]);
if (priv) {
cypress_buf_free(priv->buf);
kfree(priv);
usb_set_serial_port_data(serial->port[0], NULL);
}
}
static int cypress_open (struct usb_serial_port *port, struct file *filp)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
struct usb_serial *serial = port->serial;
unsigned long flags;
int result = 0;
dbg("%s - port %d", __FUNCTION__, port->number);
/* clear halts before open */
usb_clear_halt(serial->dev, 0x81);
usb_clear_halt(serial->dev, 0x02);
spin_lock_irqsave(&priv->lock, flags);
/* reset read/write statistics */
priv->bytes_in = 0;
priv->bytes_out = 0;
priv->cmd_count = 0;
priv->rx_flags = 0;
spin_unlock_irqrestore(&priv->lock, flags);
/* setting to zero could cause data loss */
port->tty->low_latency = 1;
/* raise both lines and set termios */
spin_lock_irqsave(&priv->lock, flags);
priv->line_control = CONTROL_DTR | CONTROL_RTS;
priv->cmd_ctrl = 1;
spin_unlock_irqrestore(&priv->lock, flags);
result = cypress_write(port, NULL, 0);
if (result) {
dev_err(&port->dev, "%s - failed setting the control lines - error %d\n", __FUNCTION__, result);
return result;
} else
dbg("%s - success setting the control lines", __FUNCTION__);
cypress_set_termios(port, &priv->tmp_termios);
/* setup the port and start reading from the device */
if(!port->interrupt_in_urb){
err("%s - interrupt_in_urb is empty!", __FUNCTION__);
return(-1);
}
usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
port->interrupt_in_urb->transfer_buffer, port->interrupt_in_urb->transfer_buffer_length,
cypress_read_int_callback, port, interval);
result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
if (result){
dev_err(&port->dev, "%s - failed submitting read urb, error %d\n", __FUNCTION__, result);
}
return result;
} /* cypress_open */
static void cypress_close(struct usb_serial_port *port, struct file * filp)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
unsigned int c_cflag;
unsigned long flags;
int bps;
long timeout;
wait_queue_t wait;
dbg("%s - port %d", __FUNCTION__, port->number);
/* wait for data to drain from buffer */
spin_lock_irqsave(&priv->lock, flags);
timeout = CYPRESS_CLOSING_WAIT;
init_waitqueue_entry(&wait, current);
add_wait_queue(&port->tty->write_wait, &wait);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (cypress_buf_data_avail(priv->buf) == 0
|| timeout == 0 || signal_pending(current)
|| !usb_get_intfdata(port->serial->interface))
break;
spin_unlock_irqrestore(&priv->lock, flags);
timeout = schedule_timeout(timeout);
spin_lock_irqsave(&priv->lock, flags);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&port->tty->write_wait, &wait);
/* clear out any remaining data in the buffer */
cypress_buf_clear(priv->buf);
spin_unlock_irqrestore(&priv->lock, flags);
/* wait for characters to drain from device */
bps = tty_get_baud_rate(port->tty);
if (bps > 1200)
timeout = max((HZ*2560)/bps,HZ/10);
else
timeout = 2*HZ;
schedule_timeout_interruptible(timeout);
dbg("%s - stopping urbs", __FUNCTION__);
usb_kill_urb (port->interrupt_in_urb);
usb_kill_urb (port->interrupt_out_urb);
if (port->tty) {
c_cflag = port->tty->termios->c_cflag;
if (c_cflag & HUPCL) {
/* drop dtr and rts */
priv = usb_get_serial_port_data(port);
spin_lock_irqsave(&priv->lock, flags);
priv->line_control = 0;
priv->cmd_ctrl = 1;
spin_unlock_irqrestore(&priv->lock, flags);
cypress_write(port, NULL, 0);
}
}
if (stats)
dev_info (&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
priv->bytes_in, priv->bytes_out, priv->cmd_count);
} /* cypress_close */
static int cypress_write(struct usb_serial_port *port, const unsigned char *buf, int count)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
dbg("%s - port %d, %d bytes", __FUNCTION__, port->number, count);
/* line control commands, which need to be executed immediately,
are not put into the buffer for obvious reasons.
*/
if (priv->cmd_ctrl) {
count = 0;
goto finish;
}
if (!count)
return count;
spin_lock_irqsave(&priv->lock, flags);
count = cypress_buf_put(priv->buf, buf, count);
spin_unlock_irqrestore(&priv->lock, flags);
finish:
cypress_send(port);
return count;
} /* cypress_write */
static void cypress_send(struct usb_serial_port *port)
{
int count = 0, result, offset, actual_size;
struct cypress_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
dbg("%s - interrupt out size is %d", __FUNCTION__, port->interrupt_out_size);
spin_lock_irqsave(&priv->lock, flags);
if (priv->write_urb_in_use) {
dbg("%s - can't write, urb in use", __FUNCTION__);
spin_unlock_irqrestore(&priv->lock, flags);
return;
}
spin_unlock_irqrestore(&priv->lock, flags);
/* clear buffer */
memset(port->interrupt_out_urb->transfer_buffer, 0, port->interrupt_out_size);
spin_lock_irqsave(&priv->lock, flags);
switch (port->interrupt_out_size) {
case 32:
/* this is for the CY7C64013... */
offset = 2;
port->interrupt_out_buffer[0] = priv->line_control;
break;
case 8:
/* this is for the CY7C63743... */
offset = 1;
port->interrupt_out_buffer[0] = priv->line_control;
break;
default:
dbg("%s - wrong packet size", __FUNCTION__);
spin_unlock_irqrestore(&priv->lock, flags);
return;
}
if (priv->line_control & CONTROL_RESET)
priv->line_control &= ~CONTROL_RESET;
if (priv->cmd_ctrl) {
priv->cmd_count++;
dbg("%s - line control command being issued", __FUNCTION__);
spin_unlock_irqrestore(&priv->lock, flags);
goto send;
} else
spin_unlock_irqrestore(&priv->lock, flags);
count = cypress_buf_get(priv->buf, &port->interrupt_out_buffer[offset],
port->interrupt_out_size-offset);
if (count == 0) {
return;
}
switch (port->interrupt_out_size) {
case 32:
port->interrupt_out_buffer[1] = count;
break;
case 8:
port->interrupt_out_buffer[0] |= count;
}
dbg("%s - count is %d", __FUNCTION__, count);
send:
spin_lock_irqsave(&priv->lock, flags);
priv->write_urb_in_use = 1;
spin_unlock_irqrestore(&priv->lock, flags);
if (priv->cmd_ctrl)
actual_size = 1;
else
actual_size = count + (port->interrupt_out_size == 32 ? 2 : 1);
usb_serial_debug_data(debug, &port->dev, __FUNCTION__, port->interrupt_out_size,
port->interrupt_out_urb->transfer_buffer);
port->interrupt_out_urb->transfer_buffer_length = actual_size;
port->interrupt_out_urb->dev = port->serial->dev;
port->interrupt_out_urb->interval = interval;
result = usb_submit_urb (port->interrupt_out_urb, GFP_ATOMIC);
if (result) {
dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__,
result);
priv->write_urb_in_use = 0;
}
spin_lock_irqsave(&priv->lock, flags);
if (priv->cmd_ctrl) {
priv->cmd_ctrl = 0;
}
priv->bytes_out += count; /* do not count the line control and size bytes */
spin_unlock_irqrestore(&priv->lock, flags);
schedule_work(&port->work);
} /* cypress_send */
/* returns how much space is available in the soft buffer */
static int cypress_write_room(struct usb_serial_port *port)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
int room = 0;
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
spin_lock_irqsave(&priv->lock, flags);
room = cypress_buf_space_avail(priv->buf);
spin_unlock_irqrestore(&priv->lock, flags);
dbg("%s - returns %d", __FUNCTION__, room);
return room;
}
static int cypress_tiocmget (struct usb_serial_port *port, struct file *file)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
__u8 status, control;
unsigned int result = 0;
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
spin_lock_irqsave(&priv->lock, flags);
control = priv->line_control;
status = priv->current_status;
spin_unlock_irqrestore(&priv->lock, flags);
result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0)
| ((control & CONTROL_RTS) ? TIOCM_RTS : 0)
| ((status & UART_CTS) ? TIOCM_CTS : 0)
| ((status & UART_DSR) ? TIOCM_DSR : 0)
| ((status & UART_RI) ? TIOCM_RI : 0)
| ((status & UART_CD) ? TIOCM_CD : 0);
dbg("%s - result = %x", __FUNCTION__, result);
return result;
}
static int cypress_tiocmset (struct usb_serial_port *port, struct file *file,
unsigned int set, unsigned int clear)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
spin_lock_irqsave(&priv->lock, flags);
if (set & TIOCM_RTS)
priv->line_control |= CONTROL_RTS;
if (set & TIOCM_DTR)
priv->line_control |= CONTROL_DTR;
if (clear & TIOCM_RTS)
priv->line_control &= ~CONTROL_RTS;
if (clear & TIOCM_DTR)
priv->line_control &= ~CONTROL_DTR;
spin_unlock_irqrestore(&priv->lock, flags);
priv->cmd_ctrl = 1;
return cypress_write(port, NULL, 0);
}
static int cypress_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
dbg("%s - port %d, cmd 0x%.4x", __FUNCTION__, port->number, cmd);
switch (cmd) {
case TIOCGSERIAL:
if (copy_to_user((void __user *)arg, port->tty->termios, sizeof(struct termios))) {
return -EFAULT;
}
return (0);
break;
case TIOCSSERIAL:
if (copy_from_user(port->tty->termios, (void __user *)arg, sizeof(struct termios))) {
return -EFAULT;
}
/* here we need to call cypress_set_termios to invoke the new settings */
cypress_set_termios(port, &priv->tmp_termios);
return (0);
break;
/* these are called when setting baud rate from gpsd */
case TCGETS:
if (copy_to_user((void __user *)arg, port->tty->termios, sizeof(struct termios))) {
return -EFAULT;
}
return (0);
break;
case TCSETS:
if (copy_from_user(port->tty->termios, (void __user *)arg, sizeof(struct termios))) {
return -EFAULT;
}
/* here we need to call cypress_set_termios to invoke the new settings */
cypress_set_termios(port, &priv->tmp_termios);
return (0);
break;
/* This code comes from drivers/char/serial.c and ftdi_sio.c */
case TIOCMIWAIT:
while (priv != NULL) {
interruptible_sleep_on(&priv->delta_msr_wait);
/* see if a signal did it */
if (signal_pending(current))
return -ERESTARTSYS;
else {
char diff = priv->diff_status;
if (diff == 0) {
return -EIO; /* no change => error */
}
/* consume all events */
priv->diff_status = 0;
/* return 0 if caller wanted to know about these bits */
if ( ((arg & TIOCM_RNG) && (diff & UART_RI)) ||
((arg & TIOCM_DSR) && (diff & UART_DSR)) ||
((arg & TIOCM_CD) && (diff & UART_CD)) ||
((arg & TIOCM_CTS) && (diff & UART_CTS)) ) {
return 0;
}
/* otherwise caller can't care less about what happened,
* and so we continue to wait for more events.
*/
}
}
return 0;
break;
default:
break;
}
dbg("%s - arg not supported - it was 0x%04x - check include/asm/ioctls.h", __FUNCTION__, cmd);
return -ENOIOCTLCMD;
} /* cypress_ioctl */
static void cypress_set_termios (struct usb_serial_port *port,
struct termios *old_termios)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
struct tty_struct *tty;
int data_bits, stop_bits, parity_type, parity_enable;
unsigned cflag, iflag, baud_mask;
unsigned long flags;
__u8 oldlines;
int linechange = 0;
dbg("%s - port %d", __FUNCTION__, port->number);
tty = port->tty;
if ((!tty) || (!tty->termios)) {
dbg("%s - no tty structures", __FUNCTION__);
return;
}
spin_lock_irqsave(&priv->lock, flags);
if (!priv->termios_initialized) {
if (priv->chiptype == CT_EARTHMATE) {
*(tty->termios) = tty_std_termios;
tty->termios->c_cflag = B4800 | CS8 | CREAD | HUPCL |
CLOCAL;
} else if (priv->chiptype == CT_CYPHIDCOM) {
*(tty->termios) = tty_std_termios;
tty->termios->c_cflag = B9600 | CS8 | CREAD | HUPCL |
CLOCAL;
}
priv->termios_initialized = 1;
}
spin_unlock_irqrestore(&priv->lock, flags);
cflag = tty->termios->c_cflag;
iflag = tty->termios->c_iflag;
/* check if there are new settings */
if (old_termios) {
if ((cflag != old_termios->c_cflag) ||
(RELEVANT_IFLAG(iflag) !=
RELEVANT_IFLAG(old_termios->c_iflag))) {
dbg("%s - attempting to set new termios settings",
__FUNCTION__);
/* should make a copy of this in case something goes
* wrong in the function, we can restore it */
spin_lock_irqsave(&priv->lock, flags);
priv->tmp_termios = *(tty->termios);
spin_unlock_irqrestore(&priv->lock, flags);
} else {
dbg("%s - nothing to do, exiting", __FUNCTION__);
return;
}
} else
return;
/* set number of data bits, parity, stop bits */
/* when parity is disabled the parity type bit is ignored */
/* 1 means 2 stop bits, 0 means 1 stop bit */
stop_bits = cflag & CSTOPB ? 1 : 0;
if (cflag & PARENB) {
parity_enable = 1;
/* 1 means odd parity, 0 means even parity */
parity_type = cflag & PARODD ? 1 : 0;
} else
parity_enable = parity_type = 0;
if (cflag & CSIZE) {
switch (cflag & CSIZE) {
case CS5:
data_bits = 0;
break;
case CS6:
data_bits = 1;
break;
case CS7:
data_bits = 2;
break;
case CS8:
data_bits = 3;
break;
default:
err("%s - CSIZE was set, but not CS5-CS8",
__FUNCTION__);
data_bits = 3;
}
} else
data_bits = 3;
spin_lock_irqsave(&priv->lock, flags);
oldlines = priv->line_control;
if ((cflag & CBAUD) == B0) {
/* drop dtr and rts */
dbg("%s - dropping the lines, baud rate 0bps", __FUNCTION__);
baud_mask = B0;
priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
} else {
baud_mask = (cflag & CBAUD);
switch(baud_mask) {
case B300:
dbg("%s - setting baud 300bps", __FUNCTION__);
break;
case B600:
dbg("%s - setting baud 600bps", __FUNCTION__);
break;
case B1200:
dbg("%s - setting baud 1200bps", __FUNCTION__);
break;
case B2400:
dbg("%s - setting baud 2400bps", __FUNCTION__);
break;
case B4800:
dbg("%s - setting baud 4800bps", __FUNCTION__);
break;
case B9600:
dbg("%s - setting baud 9600bps", __FUNCTION__);
break;
case B19200:
dbg("%s - setting baud 19200bps", __FUNCTION__);
break;
case B38400:
dbg("%s - setting baud 38400bps", __FUNCTION__);
break;
case B57600:
dbg("%s - setting baud 57600bps", __FUNCTION__);
break;
case B115200:
dbg("%s - setting baud 115200bps", __FUNCTION__);
break;
default:
dbg("%s - unknown masked baud rate", __FUNCTION__);
}
priv->line_control = (CONTROL_DTR | CONTROL_RTS);
}
spin_unlock_irqrestore(&priv->lock, flags);
dbg("%s - sending %d stop_bits, %d parity_enable, %d parity_type, "
"%d data_bits (+5)", __FUNCTION__, stop_bits,
parity_enable, parity_type, data_bits);
cypress_serial_control(port, baud_mask, data_bits, stop_bits,
parity_enable, parity_type, 0, CYPRESS_SET_CONFIG);
/* we perform a CYPRESS_GET_CONFIG so that the current settings are
* filled into the private structure this should confirm that all is
* working if it returns what we just set */
cypress_serial_control(port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
/* Here we can define custom tty settings for devices; the main tty
* termios flag base comes from empeg.c */
spin_lock_irqsave(&priv->lock, flags);
if ( (priv->chiptype == CT_EARTHMATE) && (priv->baud_rate == 4800) ) {
dbg("Using custom termios settings for a baud rate of "
"4800bps.");
/* define custom termios settings for NMEA protocol */
tty->termios->c_iflag /* input modes - */
&= ~(IGNBRK /* disable ignore break */
| BRKINT /* disable break causes interrupt */
| PARMRK /* disable mark parity errors */
| ISTRIP /* disable clear high bit of input char */
| INLCR /* disable translate NL to CR */
| IGNCR /* disable ignore CR */
| ICRNL /* disable translate CR to NL */
| IXON); /* disable enable XON/XOFF flow control */
tty->termios->c_oflag /* output modes */
&= ~OPOST; /* disable postprocess output char */
tty->termios->c_lflag /* line discipline modes */
&= ~(ECHO /* disable echo input characters */
| ECHONL /* disable echo new line */
| ICANON /* disable erase, kill, werase, and rprnt
special characters */
| ISIG /* disable interrupt, quit, and suspend
special characters */
| IEXTEN); /* disable non-POSIX special characters */
} /* CT_CYPHIDCOM: Application should handle this for device */
linechange = (priv->line_control != oldlines);
spin_unlock_irqrestore(&priv->lock, flags);
/* if necessary, set lines */
if (linechange) {
priv->cmd_ctrl = 1;
cypress_write(port, NULL, 0);
}
} /* cypress_set_termios */
/* returns amount of data still left in soft buffer */
static int cypress_chars_in_buffer(struct usb_serial_port *port)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
int chars = 0;
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
spin_lock_irqsave(&priv->lock, flags);
chars = cypress_buf_data_avail(priv->buf);
spin_unlock_irqrestore(&priv->lock, flags);
dbg("%s - returns %d", __FUNCTION__, chars);
return chars;
}
static void cypress_throttle (struct usb_serial_port *port)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
spin_lock_irqsave(&priv->lock, flags);
priv->rx_flags = THROTTLED;
spin_unlock_irqrestore(&priv->lock, flags);
}
static void cypress_unthrottle (struct usb_serial_port *port)
{
struct cypress_private *priv = usb_get_serial_port_data(port);
int actually_throttled, result;
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
spin_lock_irqsave(&priv->lock, flags);
actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
priv->rx_flags = 0;
spin_unlock_irqrestore(&priv->lock, flags);
if (actually_throttled) {
port->interrupt_in_urb->dev = port->serial->dev;
result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
if (result)
dev_err(&port->dev, "%s - failed submitting read urb, "
"error %d\n", __FUNCTION__, result);
}
}
static void cypress_read_int_callback(struct urb *urb, struct pt_regs *regs)
{
struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
struct cypress_private *priv = usb_get_serial_port_data(port);
struct tty_struct *tty;
unsigned char *data = urb->transfer_buffer;
unsigned long flags;
char tty_flag = TTY_NORMAL;
int havedata = 0;
int bytes = 0;
int result;
int i = 0;
dbg("%s - port %d", __FUNCTION__, port->number);
if (urb->status) {
dbg("%s - nonzero read status received: %d", __FUNCTION__,
urb->status);
return;
}
spin_lock_irqsave(&priv->lock, flags);
if (priv->rx_flags & THROTTLED) {
dbg("%s - now throttling", __FUNCTION__);
priv->rx_flags |= ACTUALLY_THROTTLED;
spin_unlock_irqrestore(&priv->lock, flags);
return;
}
spin_unlock_irqrestore(&priv->lock, flags);
tty = port->tty;
if (!tty) {
dbg("%s - bad tty pointer - exiting", __FUNCTION__);
return;
}
spin_lock_irqsave(&priv->lock, flags);
switch(urb->actual_length) {
case 32:
/* This is for the CY7C64013... */
priv->current_status = data[0] & 0xF8;
bytes = data[1] + 2;
i = 2;
if (bytes > 2)
havedata = 1;
break;
case 8:
/* This is for the CY7C63743... */
priv->current_status = data[0] & 0xF8;
bytes = (data[0] & 0x07) + 1;
i = 1;
if (bytes > 1)
havedata = 1;
break;
default:
dbg("%s - wrong packet size - received %d bytes",
__FUNCTION__, urb->actual_length);
spin_unlock_irqrestore(&priv->lock, flags);
goto continue_read;
}
spin_unlock_irqrestore(&priv->lock, flags);
usb_serial_debug_data (debug, &port->dev, __FUNCTION__,
urb->actual_length, data);
spin_lock_irqsave(&priv->lock, flags);
/* check to see if status has changed */
if (priv != NULL) {
if (priv->current_status != priv->prev_status) {
priv->diff_status |= priv->current_status ^
priv->prev_status;
wake_up_interruptible(&priv->delta_msr_wait);
priv->prev_status = priv->current_status;
}
}
spin_unlock_irqrestore(&priv->lock, flags);
/* hangup, as defined in acm.c... this might be a bad place for it
* though */
if (tty && !(tty->termios->c_cflag & CLOCAL) &&
!(priv->current_status & UART_CD)) {
dbg("%s - calling hangup", __FUNCTION__);
tty_hangup(tty);
goto continue_read;
}
/* There is one error bit... I'm assuming it is a parity error
* indicator as the generic firmware will set this bit to 1 if a
* parity error occurs.
* I can not find reference to any other error events. */
spin_lock_irqsave(&priv->lock, flags);
if (priv->current_status & CYP_ERROR) {
spin_unlock_irqrestore(&priv->lock, flags);
tty_flag = TTY_PARITY;
dbg("%s - Parity Error detected", __FUNCTION__);
} else
spin_unlock_irqrestore(&priv->lock, flags);
/* process read if there is data other than line status */
if (tty && (bytes > i)) {
bytes = tty_buffer_request_room(tty, bytes);
for (; i < bytes ; ++i) {
dbg("pushing byte number %d - %d - %c", i, data[i],
data[i]);
tty_insert_flip_char(tty, data[i], tty_flag);
}
tty_flip_buffer_push(port->tty);
}
spin_lock_irqsave(&priv->lock, flags);
/* control and status byte(s) are also counted */
priv->bytes_in += bytes;
spin_unlock_irqrestore(&priv->lock, flags);
continue_read:
/* Continue trying to always read... unless the port has closed. */
if (port->open_count > 0) {
usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
usb_rcvintpipe(port->serial->dev,
port->interrupt_in_endpointAddress),
port->interrupt_in_urb->transfer_buffer,
port->interrupt_in_urb->transfer_buffer_length,
cypress_read_int_callback, port, interval);
result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
if (result)
dev_err(&urb->dev->dev, "%s - failed resubmitting "
"read urb, error %d\n", __FUNCTION__,
result);
}
return;
} /* cypress_read_int_callback */
static void cypress_write_int_callback(struct urb *urb, struct pt_regs *regs)
{
struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
struct cypress_private *priv = usb_get_serial_port_data(port);
int result;
dbg("%s - port %d", __FUNCTION__, port->number);
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);
priv->write_urb_in_use = 0;
return;
case -EPIPE: /* no break needed */
usb_clear_halt(port->serial->dev, 0x02);
default:
/* error in the urb, so we have to resubmit it */
dbg("%s - Overflow in write", __FUNCTION__);
dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
port->interrupt_out_urb->transfer_buffer_length = 1;
port->interrupt_out_urb->dev = port->serial->dev;
result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
if (result)
dev_err(&urb->dev->dev, "%s - failed resubmitting write urb, error %d\n",
__FUNCTION__, result);
else
return;
}
priv->write_urb_in_use = 0;
/* send any buffered data */
cypress_send(port);
}
/*****************************************************************************
* Write buffer functions - buffering code from pl2303 used
*****************************************************************************/
/*
* cypress_buf_alloc
*
* Allocate a circular buffer and all associated memory.
*/
static struct cypress_buf *cypress_buf_alloc(unsigned int size)
{
struct cypress_buf *cb;
if (size == 0)
return NULL;
cb = (struct cypress_buf *)kmalloc(sizeof(struct cypress_buf), GFP_KERNEL);
if (cb == NULL)
return NULL;
cb->buf_buf = kmalloc(size, GFP_KERNEL);
if (cb->buf_buf == NULL) {
kfree(cb);
return NULL;
}
cb->buf_size = size;
cb->buf_get = cb->buf_put = cb->buf_buf;
return cb;
}
/*
* cypress_buf_free
*
* Free the buffer and all associated memory.
*/
static void cypress_buf_free(struct cypress_buf *cb)
{
if (cb) {
kfree(cb->buf_buf);
kfree(cb);
}
}
/*
* cypress_buf_clear
*
* Clear out all data in the circular buffer.
*/
static void cypress_buf_clear(struct cypress_buf *cb)
{
if (cb != NULL)
cb->buf_get = cb->buf_put;
/* equivalent to a get of all data available */
}
/*
* cypress_buf_data_avail
*
* Return the number of bytes of data available in the circular
* buffer.
*/
static unsigned int cypress_buf_data_avail(struct cypress_buf *cb)
{
if (cb != NULL)
return ((cb->buf_size + cb->buf_put - cb->buf_get) % cb->buf_size);
else
return 0;
}
/*
* cypress_buf_space_avail
*
* Return the number of bytes of space available in the circular
* buffer.
*/
static unsigned int cypress_buf_space_avail(struct cypress_buf *cb)
{
if (cb != NULL)
return ((cb->buf_size + cb->buf_get - cb->buf_put - 1) % cb->buf_size);
else
return 0;
}
/*
* cypress_buf_put
*
* Copy data data from a user buffer and put it into the circular buffer.
* Restrict to the amount of space available.
*
* Return the number of bytes copied.
*/
static unsigned int cypress_buf_put(struct cypress_buf *cb, const char *buf,
unsigned int count)
{
unsigned int len;
if (cb == NULL)
return 0;
len = cypress_buf_space_avail(cb);
if (count > len)
count = len;
if (count == 0)
return 0;
len = cb->buf_buf + cb->buf_size - cb->buf_put;
if (count > len) {
memcpy(cb->buf_put, buf, len);
memcpy(cb->buf_buf, buf+len, count - len);
cb->buf_put = cb->buf_buf + count - len;
} else {
memcpy(cb->buf_put, buf, count);
if (count < len)
cb->buf_put += count;
else /* count == len */
cb->buf_put = cb->buf_buf;
}
return count;
}
/*
* cypress_buf_get
*
* Get data from the circular buffer and copy to the given buffer.
* Restrict to the amount of data available.
*
* Return the number of bytes copied.
*/
static unsigned int cypress_buf_get(struct cypress_buf *cb, char *buf,
unsigned int count)
{
unsigned int len;
if (cb == NULL)
return 0;
len = cypress_buf_data_avail(cb);
if (count > len)
count = len;
if (count == 0)
return 0;
len = cb->buf_buf + cb->buf_size - cb->buf_get;
if (count > len) {
memcpy(buf, cb->buf_get, len);
memcpy(buf+len, cb->buf_buf, count - len);
cb->buf_get = cb->buf_buf + count - len;
} else {
memcpy(buf, cb->buf_get, count);
if (count < len)
cb->buf_get += count;
else /* count == len */
cb->buf_get = cb->buf_buf;
}
return count;
}
/*****************************************************************************
* Module functions
*****************************************************************************/
static int __init cypress_init(void)
{
int retval;
dbg("%s", __FUNCTION__);
retval = usb_serial_register(&cypress_earthmate_device);
if (retval)
goto failed_em_register;
retval = usb_serial_register(&cypress_hidcom_device);
if (retval)
goto failed_hidcom_register;
retval = usb_register(&cypress_driver);
if (retval)
goto failed_usb_register;
info(DRIVER_DESC " " DRIVER_VERSION);
return 0;
failed_usb_register:
usb_deregister(&cypress_driver);
failed_hidcom_register:
usb_serial_deregister(&cypress_hidcom_device);
failed_em_register:
usb_serial_deregister(&cypress_earthmate_device);
return retval;
}
static void __exit cypress_exit (void)
{
dbg("%s", __FUNCTION__);
usb_deregister (&cypress_driver);
usb_serial_deregister (&cypress_earthmate_device);
usb_serial_deregister (&cypress_hidcom_device);
}
module_init(cypress_init);
module_exit(cypress_exit);
MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
MODULE_VERSION( DRIVER_VERSION );
MODULE_LICENSE("GPL");
module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
module_param(stats, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(stats, "Enable statistics or not");
module_param(interval, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(interval, "Overrides interrupt interval");
