openwrt/target/linux/brcm2708/patches-3.10/0042-lirc-added-support-for-RaspberryPi-GPIO.patch

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From b7496d2df33f324ee6854c600944b50a011d95e0 Mon Sep 17 00:00:00 2001
From: Aron Szabo <aron@aron.ws>
Date: Sat, 16 Jun 2012 12:15:55 +0200
Subject: [PATCH 042/174] lirc: added support for RaspberryPi GPIO
---
drivers/staging/media/lirc/Kconfig | 6 +
drivers/staging/media/lirc/Makefile | 1 +
drivers/staging/media/lirc/lirc_rpi.c | 687 ++++++++++++++++++++++++++++++++++
3 files changed, 694 insertions(+)
create mode 100644 drivers/staging/media/lirc/lirc_rpi.c
--- a/drivers/staging/media/lirc/Kconfig
+++ b/drivers/staging/media/lirc/Kconfig
@@ -38,6 +38,12 @@ config LIRC_PARALLEL
help
Driver for Homebrew Parallel Port Receivers
+config LIRC_RPI
+ tristate "Homebrew GPIO Port Receiver/Transmitter for the RaspberryPi"
+ depends on LIRC
+ help
+ Driver for Homebrew GPIO Port Receiver/Transmitter for the RaspberryPi
+
config LIRC_SASEM
tristate "Sasem USB IR Remote"
depends on LIRC && USB
--- a/drivers/staging/media/lirc/Makefile
+++ b/drivers/staging/media/lirc/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_LIRC_BT829) += lirc_bt829.o
obj-$(CONFIG_LIRC_IGORPLUGUSB) += lirc_igorplugusb.o
obj-$(CONFIG_LIRC_IMON) += lirc_imon.o
obj-$(CONFIG_LIRC_PARALLEL) += lirc_parallel.o
+obj-$(CONFIG_LIRC_RPI) += lirc_rpi.o
obj-$(CONFIG_LIRC_SASEM) += lirc_sasem.o
obj-$(CONFIG_LIRC_SERIAL) += lirc_serial.o
obj-$(CONFIG_LIRC_SIR) += lirc_sir.o
--- /dev/null
+++ b/drivers/staging/media/lirc/lirc_rpi.c
@@ -0,0 +1,687 @@
+/*
+ * lirc_rpi.c
+ *
+ * lirc_rpi - Device driver that records pulse- and pause-lengths
+ * (space-lengths) (just like the lirc_serial driver does)
+ * between GPIO interrupt events on the Raspberry Pi.
+ * Lots of code has been taken from the lirc_serial module,
+ * so I would like say thanks to the authors.
+ *
+ * Copyright (C) 2012 Aron Robert Szabo <aron@reon.hu>,
+ * Michael Bishop <cleverca22@gmail.com>
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/irq.h>
+#include <linux/spinlock.h>
+#include <media/lirc.h>
+#include <media/lirc_dev.h>
+#include <linux/gpio.h>
+
+#define LIRC_DRIVER_NAME "lirc_rpi"
+#define RBUF_LEN 256
+#define LIRC_TRANSMITTER_LATENCY 256
+
+#ifndef MAX_UDELAY_MS
+#define MAX_UDELAY_US 5000
+#else
+#define MAX_UDELAY_US (MAX_UDELAY_MS*1000)
+#endif
+
+#define dprintk(fmt, args...) \
+ do { \
+ if (debug) \
+ printk(KERN_DEBUG LIRC_DRIVER_NAME ": " \
+ fmt, ## args); \
+ } while (0)
+
+/* module parameters */
+
+/* set the default GPIO input pin */
+static int gpio_in_pin = 18;
+/* set the default GPIO output pin */
+static int gpio_out_pin = 17;
+/* enable debugging messages */
+static int debug;
+/* -1 = auto, 0 = active high, 1 = active low */
+static int sense = -1;
+/* use softcarrier by default */
+static int softcarrier = 1;
+
+struct gpio_chip *gpiochip;
+struct irq_chip *irqchip;
+struct irq_data *irqdata;
+
+/* forward declarations */
+static long send_pulse(unsigned long length);
+static void send_space(long length);
+static void lirc_rpi_exit(void);
+
+int valid_gpio_pins[] = { 0, 1, 4, 8, 7, 9, 10, 11, 14, 15, 17, 18, 21, 22, 23,
+ 24, 25 };
+
+static struct platform_device *lirc_rpi_dev;
+static struct timeval lasttv = { 0, 0 };
+static struct lirc_buffer rbuf;
+static spinlock_t lock;
+
+/* initialized/set in init_timing_params() */
+static unsigned int freq = 38000;
+static unsigned int duty_cycle = 50;
+static unsigned long period;
+static unsigned long pulse_width;
+static unsigned long space_width;
+
+static void safe_udelay(unsigned long usecs)
+{
+ while (usecs > MAX_UDELAY_US) {
+ udelay(MAX_UDELAY_US);
+ usecs -= MAX_UDELAY_US;
+ }
+ udelay(usecs);
+}
+
+static int init_timing_params(unsigned int new_duty_cycle,
+ unsigned int new_freq)
+{
+ /*
+ * period, pulse/space width are kept with 8 binary places -
+ * IE multiplied by 256.
+ */
+ if (256 * 1000000L / new_freq * new_duty_cycle / 100 <=
+ LIRC_TRANSMITTER_LATENCY)
+ return -EINVAL;
+ if (256 * 1000000L / new_freq * (100 - new_duty_cycle) / 100 <=
+ LIRC_TRANSMITTER_LATENCY)
+ return -EINVAL;
+ duty_cycle = new_duty_cycle;
+ freq = new_freq;
+ period = 256 * 1000000L / freq;
+ pulse_width = period * duty_cycle / 100;
+ space_width = period - pulse_width;
+ dprintk("in init_timing_params, freq=%d pulse=%ld, "
+ "space=%ld\n", freq, pulse_width, space_width);
+ return 0;
+}
+
+static long send_pulse_softcarrier(unsigned long length)
+{
+ int flag;
+ unsigned long actual, target, d;
+
+ length <<= 8;
+
+ actual = 0; target = 0; flag = 0;
+ while (actual < length) {
+ if (flag) {
+ gpiochip->set(gpiochip, gpio_out_pin, 0);
+ target += space_width;
+ } else {
+ gpiochip->set(gpiochip, gpio_out_pin, 1);
+ target += pulse_width;
+ }
+ d = (target - actual -
+ LIRC_TRANSMITTER_LATENCY + 128) >> 8;
+ /*
+ * Note - we've checked in ioctl that the pulse/space
+ * widths are big enough so that d is > 0
+ */
+ udelay(d);
+ actual += (d << 8) + LIRC_TRANSMITTER_LATENCY;
+ flag = !flag;
+ }
+ return (actual-length) >> 8;
+}
+
+static long send_pulse(unsigned long length)
+{
+ if (length <= 0)
+ return 0;
+
+ if (softcarrier) {
+ return send_pulse_softcarrier(length);
+ } else {
+ gpiochip->set(gpiochip, gpio_out_pin, 1);
+ safe_udelay(length);
+ return 0;
+ }
+}
+
+static void send_space(long length)
+{
+ gpiochip->set(gpiochip, gpio_out_pin, 0);
+ if (length <= 0)
+ return;
+ safe_udelay(length);
+}
+
+static void rbwrite(int l)
+{
+ if (lirc_buffer_full(&rbuf)) {
+ /* no new signals will be accepted */
+ dprintk("Buffer overrun\n");
+ return;
+ }
+ lirc_buffer_write(&rbuf, (void *)&l);
+}
+
+static void frbwrite(int l)
+{
+ /* simple noise filter */
+ static int pulse, space;
+ static unsigned int ptr;
+
+ if (ptr > 0 && (l & PULSE_BIT)) {
+ pulse += l & PULSE_MASK;
+ if (pulse > 250) {
+ rbwrite(space);
+ rbwrite(pulse | PULSE_BIT);
+ ptr = 0;
+ pulse = 0;
+ }
+ return;
+ }
+ if (!(l & PULSE_BIT)) {
+ if (ptr == 0) {
+ if (l > 20000) {
+ space = l;
+ ptr++;
+ return;
+ }
+ } else {
+ if (l > 20000) {
+ space += pulse;
+ if (space > PULSE_MASK)
+ space = PULSE_MASK;
+ space += l;
+ if (space > PULSE_MASK)
+ space = PULSE_MASK;
+ pulse = 0;
+ return;
+ }
+ rbwrite(space);
+ rbwrite(pulse | PULSE_BIT);
+ ptr = 0;
+ pulse = 0;
+ }
+ }
+ rbwrite(l);
+}
+
+static irqreturn_t irq_handler(int i, void *blah, struct pt_regs *regs)
+{
+ struct timeval tv;
+ long deltv;
+ int data;
+ int signal;
+
+ /* use the GPIO signal level */
+ signal = gpiochip->get(gpiochip, gpio_in_pin);
+
+ /* unmask the irq */
+ irqchip->irq_unmask(irqdata);
+
+ if (sense != -1) {
+ /* get current time */
+ do_gettimeofday(&tv);
+
+ /* calc time since last interrupt in microseconds */
+ deltv = tv.tv_sec-lasttv.tv_sec;
+ if (tv.tv_sec < lasttv.tv_sec ||
+ (tv.tv_sec == lasttv.tv_sec &&
+ tv.tv_usec < lasttv.tv_usec)) {
+ printk(KERN_WARNING LIRC_DRIVER_NAME
+ ": AIEEEE: your clock just jumped backwards\n");
+ printk(KERN_WARNING LIRC_DRIVER_NAME
+ ": %d %d %lx %lx %lx %lx\n", signal, sense,
+ tv.tv_sec, lasttv.tv_sec,
+ tv.tv_usec, lasttv.tv_usec);
+ data = PULSE_MASK;
+ } else if (deltv > 15) {
+ data = PULSE_MASK; /* really long time */
+ if (!(signal^sense)) {
+ /* sanity check */
+ printk(KERN_WARNING LIRC_DRIVER_NAME
+ ": AIEEEE: %d %d %lx %lx %lx %lx\n",
+ signal, sense, tv.tv_sec, lasttv.tv_sec,
+ tv.tv_usec, lasttv.tv_usec);
+ /*
+ * detecting pulse while this
+ * MUST be a space!
+ */
+ sense = sense ? 0 : 1;
+ }
+ } else {
+ data = (int) (deltv*1000000 +
+ (tv.tv_usec - lasttv.tv_usec));
+ }
+ frbwrite(signal^sense ? data : (data|PULSE_BIT));
+ lasttv = tv;
+ wake_up_interruptible(&rbuf.wait_poll);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int is_right_chip(struct gpio_chip *chip, void *data)
+{
+ dprintk("is_right_chip %s %d\n", chip->label, strcmp(data, chip->label));
+
+ if (strcmp(data, chip->label) == 0)
+ return 1;
+ return 0;
+}
+
+static int init_port(void)
+{
+ int i, nlow, nhigh, ret, irq;
+
+ gpiochip = gpiochip_find("bcm2708_gpio", is_right_chip);
+
+ if (!gpiochip)
+ return -ENODEV;
+
+ if (gpio_request(gpio_out_pin, LIRC_DRIVER_NAME " ir/out")) {
+ printk(KERN_ALERT LIRC_DRIVER_NAME
+ ": cant claim gpio pin %d\n", gpio_out_pin);
+ ret = -ENODEV;
+ goto exit_init_port;
+ }
+
+ if (gpio_request(gpio_in_pin, LIRC_DRIVER_NAME " ir/in")) {
+ printk(KERN_ALERT LIRC_DRIVER_NAME
+ ": cant claim gpio pin %d\n", gpio_in_pin);
+ ret = -ENODEV;
+ goto exit_gpio_free_out_pin;
+ }
+
+ gpiochip->direction_input(gpiochip, gpio_in_pin);
+ gpiochip->direction_output(gpiochip, gpio_out_pin, 1);
+ gpiochip->set(gpiochip, gpio_out_pin, 0);
+
+ irq = gpiochip->to_irq(gpiochip, gpio_in_pin);
+ dprintk("to_irq %d\n", irq);
+ irqdata = irq_get_irq_data(irq);
+
+ if (irqdata && irqdata->chip) {
+ irqchip = irqdata->chip;
+ } else {
+ ret = -ENODEV;
+ goto exit_gpio_free_in_pin;
+ }
+
+ /* if pin is high, then this must be an active low receiver. */
+ if (sense == -1) {
+ /* wait 1/2 sec for the power supply */
+ msleep(500);
+
+ /*
+ * probe 9 times every 0.04s, collect "votes" for
+ * active high/low
+ */
+ nlow = 0;
+ nhigh = 0;
+ for (i = 0; i < 9; i++) {
+ if (gpiochip->get(gpiochip, gpio_in_pin))
+ nlow++;
+ else
+ nhigh++;
+ msleep(40);
+ }
+ sense = (nlow >= nhigh ? 1 : 0);
+ printk(KERN_INFO LIRC_DRIVER_NAME
+ ": auto-detected active %s receiver on GPIO pin %d\n",
+ sense ? "low" : "high", gpio_in_pin);
+ } else {
+ printk(KERN_INFO LIRC_DRIVER_NAME
+ ": manually using active %s receiver on GPIO pin %d\n",
+ sense ? "low" : "high", gpio_in_pin);
+ }
+
+ return 0;
+
+ exit_gpio_free_in_pin:
+ gpio_free(gpio_in_pin);
+
+ exit_gpio_free_out_pin:
+ gpio_free(gpio_out_pin);
+
+ exit_init_port:
+ return ret;
+}
+
+// called when the character device is opened
+static int set_use_inc(void *data)
+{
+ int result;
+ unsigned long flags;
+
+ /* initialize timestamp */
+ do_gettimeofday(&lasttv);
+
+ result = request_irq(gpiochip->to_irq(gpiochip, gpio_in_pin),
+ (irq_handler_t) irq_handler, 0,
+ LIRC_DRIVER_NAME, (void*) 0);
+
+ switch (result) {
+ case -EBUSY:
+ printk(KERN_ERR LIRC_DRIVER_NAME
+ ": IRQ %d is busy\n",
+ gpiochip->to_irq(gpiochip, gpio_in_pin));
+ return -EBUSY;
+ case -EINVAL:
+ printk(KERN_ERR LIRC_DRIVER_NAME
+ ": Bad irq number or handler\n");
+ return -EINVAL;
+ default:
+ dprintk("Interrupt %d obtained\n",
+ gpiochip->to_irq(gpiochip, gpio_in_pin));
+ break;
+ };
+
+ /* initialize pulse/space widths */
+ init_timing_params(duty_cycle, freq);
+
+ spin_lock_irqsave(&lock, flags);
+
+ /* GPIO Pin Falling/Rising Edge Detect Enable */
+ irqchip->irq_set_type(irqdata,
+ IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING);
+
+ /* unmask the irq */
+ irqchip->irq_unmask(irqdata);
+
+ spin_unlock_irqrestore(&lock, flags);
+
+ return 0;
+}
+
+static void set_use_dec(void *data)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&lock, flags);
+
+ /* GPIO Pin Falling/Rising Edge Detect Disable */
+ irqchip->irq_set_type(irqdata, 0);
+ irqchip->irq_mask(irqdata);
+
+ spin_unlock_irqrestore(&lock, flags);
+
+ free_irq(gpiochip->to_irq(gpiochip, gpio_in_pin), (void *) 0);
+
+ dprintk(KERN_INFO LIRC_DRIVER_NAME
+ ": freed IRQ %d\n", gpiochip->to_irq(gpiochip, gpio_in_pin));
+}
+
+static ssize_t lirc_write(struct file *file, const char *buf,
+ size_t n, loff_t *ppos)
+{
+ int i, count;
+ unsigned long flags;
+ long delta = 0;
+ int *wbuf;
+
+ count = n / sizeof(int);
+ if (n % sizeof(int) || count % 2 == 0)
+ return -EINVAL;
+ wbuf = memdup_user(buf, n);
+ if (IS_ERR(wbuf))
+ return PTR_ERR(wbuf);
+ spin_lock_irqsave(&lock, flags);
+
+ for (i = 0; i < count; i++) {
+ if (i%2)
+ send_space(wbuf[i] - delta);
+ else
+ delta = send_pulse(wbuf[i]);
+ }
+ gpiochip->set(gpiochip, gpio_out_pin, 0);
+
+ spin_unlock_irqrestore(&lock, flags);
+ kfree(wbuf);
+ return n;
+}
+
+static long lirc_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
+{
+ int result;
+ __u32 value;
+
+ switch (cmd) {
+ case LIRC_GET_SEND_MODE:
+ return -ENOIOCTLCMD;
+ break;
+
+ case LIRC_SET_SEND_MODE:
+ result = get_user(value, (__u32 *) arg);
+ if (result)
+ return result;
+ /* only LIRC_MODE_PULSE supported */
+ if (value != LIRC_MODE_PULSE)
+ return -ENOSYS;
+ break;
+
+ case LIRC_GET_LENGTH:
+ return -ENOSYS;
+ break;
+
+ case LIRC_SET_SEND_DUTY_CYCLE:
+ dprintk("SET_SEND_DUTY_CYCLE\n");
+ result = get_user(value, (__u32 *) arg);
+ if (result)
+ return result;
+ if (value <= 0 || value > 100)
+ return -EINVAL;
+ return init_timing_params(value, freq);
+ break;
+
+ case LIRC_SET_SEND_CARRIER:
+ dprintk("SET_SEND_CARRIER\n");
+ result = get_user(value, (__u32 *) arg);
+ if (result)
+ return result;
+ if (value > 500000 || value < 20000)
+ return -EINVAL;
+ return init_timing_params(duty_cycle, value);
+ break;
+
+ default:
+ return lirc_dev_fop_ioctl(filep, cmd, arg);
+ }
+ return 0;
+}
+
+static const struct file_operations lirc_fops = {
+ .owner = THIS_MODULE,
+ .write = lirc_write,
+ .unlocked_ioctl = lirc_ioctl,
+ .read = lirc_dev_fop_read,
+ .poll = lirc_dev_fop_poll,
+ .open = lirc_dev_fop_open,
+ .release = lirc_dev_fop_close,
+ .llseek = no_llseek,
+};
+
+static struct lirc_driver driver = {
+ .name = LIRC_DRIVER_NAME,
+ .minor = -1,
+ .code_length = 1,
+ .sample_rate = 0,
+ .data = NULL,
+ .add_to_buf = NULL,
+ .rbuf = &rbuf,
+ .set_use_inc = set_use_inc,
+ .set_use_dec = set_use_dec,
+ .fops = &lirc_fops,
+ .dev = NULL,
+ .owner = THIS_MODULE,
+};
+
+static struct platform_driver lirc_rpi_driver = {
+ .driver = {
+ .name = LIRC_DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init lirc_rpi_init(void)
+{
+ int result;
+
+ /* Init read buffer. */
+ result = lirc_buffer_init(&rbuf, sizeof(int), RBUF_LEN);
+ if (result < 0)
+ return -ENOMEM;
+
+ result = platform_driver_register(&lirc_rpi_driver);
+ if (result) {
+ printk(KERN_ERR LIRC_DRIVER_NAME
+ ": lirc register returned %d\n", result);
+ goto exit_buffer_free;
+ }
+
+ lirc_rpi_dev = platform_device_alloc(LIRC_DRIVER_NAME, 0);
+ if (!lirc_rpi_dev) {
+ result = -ENOMEM;
+ goto exit_driver_unregister;
+ }
+
+ result = platform_device_add(lirc_rpi_dev);
+ if (result)
+ goto exit_device_put;
+
+ return 0;
+
+ exit_device_put:
+ platform_device_put(lirc_rpi_dev);
+
+ exit_driver_unregister:
+ platform_driver_unregister(&lirc_rpi_driver);
+
+ exit_buffer_free:
+ lirc_buffer_free(&rbuf);
+
+ return result;
+}
+
+static void lirc_rpi_exit(void)
+{
+ gpio_free(gpio_out_pin);
+ gpio_free(gpio_in_pin);
+ platform_device_unregister(lirc_rpi_dev);
+ platform_driver_unregister(&lirc_rpi_driver);
+ lirc_buffer_free(&rbuf);
+}
+
+static int __init lirc_rpi_init_module(void)
+{
+ int result, i;
+
+ result = lirc_rpi_init();
+ if (result)
+ return result;
+
+ /* check if the module received valid gpio pin numbers */
+ result = 0;
+ if (gpio_in_pin != gpio_out_pin) {
+ for(i = 0; (i < ARRAY_SIZE(valid_gpio_pins)) && (result != 2); i++) {
+ if (gpio_in_pin == valid_gpio_pins[i] ||
+ gpio_out_pin == valid_gpio_pins[i]) {
+ result++;
+ }
+ }
+ }
+
+ if (result != 2) {
+ result = -EINVAL;
+ printk(KERN_ERR LIRC_DRIVER_NAME
+ ": invalid GPIO pin(s) specified!\n");
+ goto exit_rpi;
+ }
+
+ driver.features = LIRC_CAN_SET_SEND_DUTY_CYCLE |
+ LIRC_CAN_SET_SEND_CARRIER |
+ LIRC_CAN_SEND_PULSE |
+ LIRC_CAN_REC_MODE2;
+
+ driver.dev = &lirc_rpi_dev->dev;
+ driver.minor = lirc_register_driver(&driver);
+
+ if (driver.minor < 0) {
+ printk(KERN_ERR LIRC_DRIVER_NAME
+ ": device registration failed with %d\n", result);
+ result = -EIO;
+ goto exit_rpi;
+ }
+
+ printk(KERN_INFO LIRC_DRIVER_NAME ": driver registered!\n");
+
+ result = init_port();
+ if (result < 0)
+ goto exit_rpi;
+
+ return 0;
+
+ exit_rpi:
+ lirc_rpi_exit();
+
+ return result;
+}
+
+static void __exit lirc_rpi_exit_module(void)
+{
+ lirc_rpi_exit();
+
+ lirc_unregister_driver(driver.minor);
+ printk(KERN_INFO LIRC_DRIVER_NAME ": cleaned up module\n");
+}
+
+module_init(lirc_rpi_init_module);
+module_exit(lirc_rpi_exit_module);
+
+MODULE_DESCRIPTION("Infra-red receiver and blaster driver for Raspberry Pi GPIO.");
+MODULE_AUTHOR("Aron Robert Szabo <aron@reon.hu>");
+MODULE_AUTHOR("Michael Bishop <cleverca22@gmail.com>");
+MODULE_LICENSE("GPL");
+
+module_param(gpio_out_pin, int, S_IRUGO);
+MODULE_PARM_DESC(gpio_out_pin, "GPIO output/transmitter pin number of the BCM"
+ " processor. Valid pin numbers are: 0, 1, 4, 8, 7, 9, 10, 11,"
+ " 14, 15, 17, 18, 21, 22, 23, 24, 25, default 17");
+
+module_param(gpio_in_pin, int, S_IRUGO);
+MODULE_PARM_DESC(gpio_in_pin, "GPIO input pin number of the BCM processor."
+ " Valid pin numbers are: 0, 1, 4, 8, 7, 9, 10, 11, 14, 15,"
+ " 17, 18, 21, 22, 23, 24, 25, default 18");
+
+module_param(sense, bool, S_IRUGO);
+MODULE_PARM_DESC(sense, "Override autodetection of IR receiver circuit"
+ " (0 = active high, 1 = active low )");
+
+module_param(softcarrier, bool, S_IRUGO);
+MODULE_PARM_DESC(softcarrier, "Software carrier (0 = off, 1 = on, default on)");
+
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Enable debugging messages");