linux/drivers/net/ieee802154/mrf24j40.c

768 lines
19 KiB
C

/*
* Driver for Microchip MRF24J40 802.15.4 Wireless-PAN Networking controller
*
* Copyright (C) 2012 Alan Ott <alan@signal11.us>
* Signal 11 Software
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/spi/spi.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <net/wpan-phy.h>
#include <net/mac802154.h>
/* MRF24J40 Short Address Registers */
#define REG_RXMCR 0x00 /* Receive MAC control */
#define REG_PANIDL 0x01 /* PAN ID (low) */
#define REG_PANIDH 0x02 /* PAN ID (high) */
#define REG_SADRL 0x03 /* Short address (low) */
#define REG_SADRH 0x04 /* Short address (high) */
#define REG_EADR0 0x05 /* Long address (low) (high is EADR7) */
#define REG_TXMCR 0x11 /* Transmit MAC control */
#define REG_PACON0 0x16 /* Power Amplifier Control */
#define REG_PACON1 0x17 /* Power Amplifier Control */
#define REG_PACON2 0x18 /* Power Amplifier Control */
#define REG_TXNCON 0x1B /* Transmit Normal FIFO Control */
#define REG_TXSTAT 0x24 /* TX MAC Status Register */
#define REG_SOFTRST 0x2A /* Soft Reset */
#define REG_TXSTBL 0x2E /* TX Stabilization */
#define REG_INTSTAT 0x31 /* Interrupt Status */
#define REG_INTCON 0x32 /* Interrupt Control */
#define REG_RFCTL 0x36 /* RF Control Mode Register */
#define REG_BBREG1 0x39 /* Baseband Registers */
#define REG_BBREG2 0x3A /* */
#define REG_BBREG6 0x3E /* */
#define REG_CCAEDTH 0x3F /* Energy Detection Threshold */
/* MRF24J40 Long Address Registers */
#define REG_RFCON0 0x200 /* RF Control Registers */
#define REG_RFCON1 0x201
#define REG_RFCON2 0x202
#define REG_RFCON3 0x203
#define REG_RFCON5 0x205
#define REG_RFCON6 0x206
#define REG_RFCON7 0x207
#define REG_RFCON8 0x208
#define REG_RSSI 0x210
#define REG_SLPCON0 0x211 /* Sleep Clock Control Registers */
#define REG_SLPCON1 0x220
#define REG_WAKETIMEL 0x222 /* Wake-up Time Match Value Low */
#define REG_WAKETIMEH 0x223 /* Wake-up Time Match Value High */
#define REG_RX_FIFO 0x300 /* Receive FIFO */
/* Device configuration: Only channels 11-26 on page 0 are supported. */
#define MRF24J40_CHAN_MIN 11
#define MRF24J40_CHAN_MAX 26
#define CHANNEL_MASK (((u32)1 << (MRF24J40_CHAN_MAX + 1)) \
- ((u32)1 << MRF24J40_CHAN_MIN))
#define TX_FIFO_SIZE 128 /* From datasheet */
#define RX_FIFO_SIZE 144 /* From datasheet */
#define SET_CHANNEL_DELAY_US 192 /* From datasheet */
/* Device Private Data */
struct mrf24j40 {
struct spi_device *spi;
struct ieee802154_dev *dev;
struct mutex buffer_mutex; /* only used to protect buf */
struct completion tx_complete;
struct work_struct irqwork;
u8 *buf; /* 3 bytes. Used for SPI single-register transfers. */
};
/* Read/Write SPI Commands for Short and Long Address registers. */
#define MRF24J40_READSHORT(reg) ((reg) << 1)
#define MRF24J40_WRITESHORT(reg) ((reg) << 1 | 1)
#define MRF24J40_READLONG(reg) (1 << 15 | (reg) << 5)
#define MRF24J40_WRITELONG(reg) (1 << 15 | (reg) << 5 | 1 << 4)
/* Maximum speed to run the device at. TODO: Get the real max value from
* someone at Microchip since it isn't in the datasheet. */
#define MAX_SPI_SPEED_HZ 1000000
#define printdev(X) (&X->spi->dev)
static int write_short_reg(struct mrf24j40 *devrec, u8 reg, u8 value)
{
int ret;
struct spi_message msg;
struct spi_transfer xfer = {
.len = 2,
.tx_buf = devrec->buf,
.rx_buf = devrec->buf,
};
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
mutex_lock(&devrec->buffer_mutex);
devrec->buf[0] = MRF24J40_WRITESHORT(reg);
devrec->buf[1] = value;
ret = spi_sync(devrec->spi, &msg);
if (ret)
dev_err(printdev(devrec),
"SPI write Failed for short register 0x%hhx\n", reg);
mutex_unlock(&devrec->buffer_mutex);
return ret;
}
static int read_short_reg(struct mrf24j40 *devrec, u8 reg, u8 *val)
{
int ret = -1;
struct spi_message msg;
struct spi_transfer xfer = {
.len = 2,
.tx_buf = devrec->buf,
.rx_buf = devrec->buf,
};
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
mutex_lock(&devrec->buffer_mutex);
devrec->buf[0] = MRF24J40_READSHORT(reg);
devrec->buf[1] = 0;
ret = spi_sync(devrec->spi, &msg);
if (ret)
dev_err(printdev(devrec),
"SPI read Failed for short register 0x%hhx\n", reg);
else
*val = devrec->buf[1];
mutex_unlock(&devrec->buffer_mutex);
return ret;
}
static int read_long_reg(struct mrf24j40 *devrec, u16 reg, u8 *value)
{
int ret;
u16 cmd;
struct spi_message msg;
struct spi_transfer xfer = {
.len = 3,
.tx_buf = devrec->buf,
.rx_buf = devrec->buf,
};
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
cmd = MRF24J40_READLONG(reg);
mutex_lock(&devrec->buffer_mutex);
devrec->buf[0] = cmd >> 8 & 0xff;
devrec->buf[1] = cmd & 0xff;
devrec->buf[2] = 0;
ret = spi_sync(devrec->spi, &msg);
if (ret)
dev_err(printdev(devrec),
"SPI read Failed for long register 0x%hx\n", reg);
else
*value = devrec->buf[2];
mutex_unlock(&devrec->buffer_mutex);
return ret;
}
static int write_long_reg(struct mrf24j40 *devrec, u16 reg, u8 val)
{
int ret;
u16 cmd;
struct spi_message msg;
struct spi_transfer xfer = {
.len = 3,
.tx_buf = devrec->buf,
.rx_buf = devrec->buf,
};
spi_message_init(&msg);
spi_message_add_tail(&xfer, &msg);
cmd = MRF24J40_WRITELONG(reg);
mutex_lock(&devrec->buffer_mutex);
devrec->buf[0] = cmd >> 8 & 0xff;
devrec->buf[1] = cmd & 0xff;
devrec->buf[2] = val;
ret = spi_sync(devrec->spi, &msg);
if (ret)
dev_err(printdev(devrec),
"SPI write Failed for long register 0x%hx\n", reg);
mutex_unlock(&devrec->buffer_mutex);
return ret;
}
/* This function relies on an undocumented write method. Once a write command
and address is set, as many bytes of data as desired can be clocked into
the device. The datasheet only shows setting one byte at a time. */
static int write_tx_buf(struct mrf24j40 *devrec, u16 reg,
const u8 *data, size_t length)
{
int ret;
u16 cmd;
u8 lengths[2];
struct spi_message msg;
struct spi_transfer addr_xfer = {
.len = 2,
.tx_buf = devrec->buf,
};
struct spi_transfer lengths_xfer = {
.len = 2,
.tx_buf = &lengths, /* TODO: Is DMA really required for SPI? */
};
struct spi_transfer data_xfer = {
.len = length,
.tx_buf = data,
};
/* Range check the length. 2 bytes are used for the length fields.*/
if (length > TX_FIFO_SIZE-2) {
dev_err(printdev(devrec), "write_tx_buf() was passed too large a buffer. Performing short write.\n");
length = TX_FIFO_SIZE-2;
}
spi_message_init(&msg);
spi_message_add_tail(&addr_xfer, &msg);
spi_message_add_tail(&lengths_xfer, &msg);
spi_message_add_tail(&data_xfer, &msg);
cmd = MRF24J40_WRITELONG(reg);
mutex_lock(&devrec->buffer_mutex);
devrec->buf[0] = cmd >> 8 & 0xff;
devrec->buf[1] = cmd & 0xff;
lengths[0] = 0x0; /* Header Length. Set to 0 for now. TODO */
lengths[1] = length; /* Total length */
ret = spi_sync(devrec->spi, &msg);
if (ret)
dev_err(printdev(devrec), "SPI write Failed for TX buf\n");
mutex_unlock(&devrec->buffer_mutex);
return ret;
}
static int mrf24j40_read_rx_buf(struct mrf24j40 *devrec,
u8 *data, u8 *len, u8 *lqi)
{
u8 rx_len;
u8 addr[2];
u8 lqi_rssi[2];
u16 cmd;
int ret;
struct spi_message msg;
struct spi_transfer addr_xfer = {
.len = 2,
.tx_buf = &addr,
};
struct spi_transfer data_xfer = {
.len = 0x0, /* set below */
.rx_buf = data,
};
struct spi_transfer status_xfer = {
.len = 2,
.rx_buf = &lqi_rssi,
};
/* Get the length of the data in the RX FIFO. The length in this
* register exclues the 1-byte length field at the beginning. */
ret = read_long_reg(devrec, REG_RX_FIFO, &rx_len);
if (ret)
goto out;
/* Range check the RX FIFO length, accounting for the one-byte
* length field at the begining. */
if (rx_len > RX_FIFO_SIZE-1) {
dev_err(printdev(devrec), "Invalid length read from device. Performing short read.\n");
rx_len = RX_FIFO_SIZE-1;
}
if (rx_len > *len) {
/* Passed in buffer wasn't big enough. Should never happen. */
dev_err(printdev(devrec), "Buffer not big enough. Performing short read\n");
rx_len = *len;
}
/* Set up the commands to read the data. */
cmd = MRF24J40_READLONG(REG_RX_FIFO+1);
addr[0] = cmd >> 8 & 0xff;
addr[1] = cmd & 0xff;
data_xfer.len = rx_len;
spi_message_init(&msg);
spi_message_add_tail(&addr_xfer, &msg);
spi_message_add_tail(&data_xfer, &msg);
spi_message_add_tail(&status_xfer, &msg);
ret = spi_sync(devrec->spi, &msg);
if (ret) {
dev_err(printdev(devrec), "SPI RX Buffer Read Failed.\n");
goto out;
}
*lqi = lqi_rssi[0];
*len = rx_len;
#ifdef DEBUG
print_hex_dump(KERN_DEBUG, "mrf24j40 rx: ",
DUMP_PREFIX_OFFSET, 16, 1, data, *len, 0);
printk(KERN_DEBUG "mrf24j40 rx: lqi: %02hhx rssi: %02hhx\n",
lqi_rssi[0], lqi_rssi[1]);
#endif
out:
return ret;
}
static int mrf24j40_tx(struct ieee802154_dev *dev, struct sk_buff *skb)
{
struct mrf24j40 *devrec = dev->priv;
u8 val;
int ret = 0;
dev_dbg(printdev(devrec), "tx packet of %d bytes\n", skb->len);
ret = write_tx_buf(devrec, 0x000, skb->data, skb->len);
if (ret)
goto err;
/* Set TXNTRIG bit of TXNCON to send packet */
ret = read_short_reg(devrec, REG_TXNCON, &val);
if (ret)
goto err;
val |= 0x1;
val &= ~0x4;
write_short_reg(devrec, REG_TXNCON, val);
INIT_COMPLETION(devrec->tx_complete);
/* Wait for the device to send the TX complete interrupt. */
ret = wait_for_completion_interruptible_timeout(
&devrec->tx_complete,
5 * HZ);
if (ret == -ERESTARTSYS)
goto err;
if (ret == 0) {
ret = -ETIMEDOUT;
goto err;
}
/* Check for send error from the device. */
ret = read_short_reg(devrec, REG_TXSTAT, &val);
if (ret)
goto err;
if (val & 0x1) {
dev_err(printdev(devrec), "Error Sending. Retry count exceeded\n");
ret = -ECOMM; /* TODO: Better error code ? */
} else
dev_dbg(printdev(devrec), "Packet Sent\n");
err:
return ret;
}
static int mrf24j40_ed(struct ieee802154_dev *dev, u8 *level)
{
/* TODO: */
printk(KERN_WARNING "mrf24j40: ed not implemented\n");
*level = 0;
return 0;
}
static int mrf24j40_start(struct ieee802154_dev *dev)
{
struct mrf24j40 *devrec = dev->priv;
u8 val;
int ret;
dev_dbg(printdev(devrec), "start\n");
ret = read_short_reg(devrec, REG_INTCON, &val);
if (ret)
return ret;
val &= ~(0x1|0x8); /* Clear TXNIE and RXIE. Enable interrupts */
write_short_reg(devrec, REG_INTCON, val);
return 0;
}
static void mrf24j40_stop(struct ieee802154_dev *dev)
{
struct mrf24j40 *devrec = dev->priv;
u8 val;
int ret;
dev_dbg(printdev(devrec), "stop\n");
ret = read_short_reg(devrec, REG_INTCON, &val);
if (ret)
return;
val |= 0x1|0x8; /* Set TXNIE and RXIE. Disable Interrupts */
write_short_reg(devrec, REG_INTCON, val);
return;
}
static int mrf24j40_set_channel(struct ieee802154_dev *dev,
int page, int channel)
{
struct mrf24j40 *devrec = dev->priv;
u8 val;
int ret;
dev_dbg(printdev(devrec), "Set Channel %d\n", channel);
WARN_ON(page != 0);
WARN_ON(channel < MRF24J40_CHAN_MIN);
WARN_ON(channel > MRF24J40_CHAN_MAX);
/* Set Channel TODO */
val = (channel-11) << 4 | 0x03;
write_long_reg(devrec, REG_RFCON0, val);
/* RF Reset */
ret = read_short_reg(devrec, REG_RFCTL, &val);
if (ret)
return ret;
val |= 0x04;
write_short_reg(devrec, REG_RFCTL, val);
val &= ~0x04;
write_short_reg(devrec, REG_RFCTL, val);
udelay(SET_CHANNEL_DELAY_US); /* per datasheet */
return 0;
}
static int mrf24j40_filter(struct ieee802154_dev *dev,
struct ieee802154_hw_addr_filt *filt,
unsigned long changed)
{
struct mrf24j40 *devrec = dev->priv;
dev_dbg(printdev(devrec), "filter\n");
if (changed & IEEE802515_AFILT_SADDR_CHANGED) {
/* Short Addr */
u8 addrh, addrl;
addrh = filt->short_addr >> 8 & 0xff;
addrl = filt->short_addr & 0xff;
write_short_reg(devrec, REG_SADRH, addrh);
write_short_reg(devrec, REG_SADRL, addrl);
dev_dbg(printdev(devrec),
"Set short addr to %04hx\n", filt->short_addr);
}
if (changed & IEEE802515_AFILT_IEEEADDR_CHANGED) {
/* Device Address */
int i;
for (i = 0; i < 8; i++)
write_short_reg(devrec, REG_EADR0+i,
filt->ieee_addr[i]);
#ifdef DEBUG
printk(KERN_DEBUG "Set long addr to: ");
for (i = 0; i < 8; i++)
printk("%02hhx ", filt->ieee_addr[i]);
printk(KERN_DEBUG "\n");
#endif
}
if (changed & IEEE802515_AFILT_PANID_CHANGED) {
/* PAN ID */
u8 panidl, panidh;
panidh = filt->pan_id >> 8 & 0xff;
panidl = filt->pan_id & 0xff;
write_short_reg(devrec, REG_PANIDH, panidh);
write_short_reg(devrec, REG_PANIDL, panidl);
dev_dbg(printdev(devrec), "Set PANID to %04hx\n", filt->pan_id);
}
if (changed & IEEE802515_AFILT_PANC_CHANGED) {
/* Pan Coordinator */
u8 val;
int ret;
ret = read_short_reg(devrec, REG_RXMCR, &val);
if (ret)
return ret;
if (filt->pan_coord)
val |= 0x8;
else
val &= ~0x8;
write_short_reg(devrec, REG_RXMCR, val);
/* REG_SLOTTED is maintained as default (unslotted/CSMA-CA).
* REG_ORDER is maintained as default (no beacon/superframe).
*/
dev_dbg(printdev(devrec), "Set Pan Coord to %s\n",
filt->pan_coord ? "on" : "off");
}
return 0;
}
static int mrf24j40_handle_rx(struct mrf24j40 *devrec)
{
u8 len = RX_FIFO_SIZE;
u8 lqi = 0;
u8 val;
int ret = 0;
struct sk_buff *skb;
/* Turn off reception of packets off the air. This prevents the
* device from overwriting the buffer while we're reading it. */
ret = read_short_reg(devrec, REG_BBREG1, &val);
if (ret)
goto out;
val |= 4; /* SET RXDECINV */
write_short_reg(devrec, REG_BBREG1, val);
skb = alloc_skb(len, GFP_KERNEL);
if (!skb) {
ret = -ENOMEM;
goto out;
}
ret = mrf24j40_read_rx_buf(devrec, skb_put(skb, len), &len, &lqi);
if (ret < 0) {
dev_err(printdev(devrec), "Failure reading RX FIFO\n");
kfree_skb(skb);
ret = -EINVAL;
goto out;
}
/* Cut off the checksum */
skb_trim(skb, len-2);
/* TODO: Other drivers call ieee20154_rx_irqsafe() here (eg: cc2040,
* also from a workqueue). I think irqsafe is not necessary here.
* Can someone confirm? */
ieee802154_rx_irqsafe(devrec->dev, skb, lqi);
dev_dbg(printdev(devrec), "RX Handled\n");
out:
/* Turn back on reception of packets off the air. */
ret = read_short_reg(devrec, REG_BBREG1, &val);
if (ret)
return ret;
val &= ~0x4; /* Clear RXDECINV */
write_short_reg(devrec, REG_BBREG1, val);
return ret;
}
static struct ieee802154_ops mrf24j40_ops = {
.owner = THIS_MODULE,
.xmit = mrf24j40_tx,
.ed = mrf24j40_ed,
.start = mrf24j40_start,
.stop = mrf24j40_stop,
.set_channel = mrf24j40_set_channel,
.set_hw_addr_filt = mrf24j40_filter,
};
static irqreturn_t mrf24j40_isr(int irq, void *data)
{
struct mrf24j40 *devrec = data;
disable_irq_nosync(irq);
schedule_work(&devrec->irqwork);
return IRQ_HANDLED;
}
static void mrf24j40_isrwork(struct work_struct *work)
{
struct mrf24j40 *devrec = container_of(work, struct mrf24j40, irqwork);
u8 intstat;
int ret;
/* Read the interrupt status */
ret = read_short_reg(devrec, REG_INTSTAT, &intstat);
if (ret)
goto out;
/* Check for TX complete */
if (intstat & 0x1)
complete(&devrec->tx_complete);
/* Check for Rx */
if (intstat & 0x8)
mrf24j40_handle_rx(devrec);
out:
enable_irq(devrec->spi->irq);
}
static int mrf24j40_probe(struct spi_device *spi)
{
int ret = -ENOMEM;
u8 val;
struct mrf24j40 *devrec;
printk(KERN_INFO "mrf24j40: probe(). IRQ: %d\n", spi->irq);
devrec = kzalloc(sizeof(struct mrf24j40), GFP_KERNEL);
if (!devrec)
goto err_devrec;
devrec->buf = kzalloc(3, GFP_KERNEL);
if (!devrec->buf)
goto err_buf;
spi->mode = SPI_MODE_0; /* TODO: Is this appropriate for right here? */
if (spi->max_speed_hz > MAX_SPI_SPEED_HZ)
spi->max_speed_hz = MAX_SPI_SPEED_HZ;
mutex_init(&devrec->buffer_mutex);
init_completion(&devrec->tx_complete);
INIT_WORK(&devrec->irqwork, mrf24j40_isrwork);
devrec->spi = spi;
dev_set_drvdata(&spi->dev, devrec);
/* Register with the 802154 subsystem */
devrec->dev = ieee802154_alloc_device(0, &mrf24j40_ops);
if (!devrec->dev)
goto err_alloc_dev;
devrec->dev->priv = devrec;
devrec->dev->parent = &devrec->spi->dev;
devrec->dev->phy->channels_supported[0] = CHANNEL_MASK;
devrec->dev->flags = IEEE802154_HW_OMIT_CKSUM|IEEE802154_HW_AACK;
dev_dbg(printdev(devrec), "registered mrf24j40\n");
ret = ieee802154_register_device(devrec->dev);
if (ret)
goto err_register_device;
/* Initialize the device.
From datasheet section 3.2: Initialization. */
write_short_reg(devrec, REG_SOFTRST, 0x07);
write_short_reg(devrec, REG_PACON2, 0x98);
write_short_reg(devrec, REG_TXSTBL, 0x95);
write_long_reg(devrec, REG_RFCON0, 0x03);
write_long_reg(devrec, REG_RFCON1, 0x01);
write_long_reg(devrec, REG_RFCON2, 0x80);
write_long_reg(devrec, REG_RFCON6, 0x90);
write_long_reg(devrec, REG_RFCON7, 0x80);
write_long_reg(devrec, REG_RFCON8, 0x10);
write_long_reg(devrec, REG_SLPCON1, 0x21);
write_short_reg(devrec, REG_BBREG2, 0x80);
write_short_reg(devrec, REG_CCAEDTH, 0x60);
write_short_reg(devrec, REG_BBREG6, 0x40);
write_short_reg(devrec, REG_RFCTL, 0x04);
write_short_reg(devrec, REG_RFCTL, 0x0);
udelay(192);
/* Set RX Mode. RXMCR<1:0>: 0x0 normal, 0x1 promisc, 0x2 error */
ret = read_short_reg(devrec, REG_RXMCR, &val);
if (ret)
goto err_read_reg;
val &= ~0x3; /* Clear RX mode (normal) */
write_short_reg(devrec, REG_RXMCR, val);
ret = request_irq(spi->irq,
mrf24j40_isr,
IRQF_TRIGGER_FALLING,
dev_name(&spi->dev),
devrec);
if (ret) {
dev_err(printdev(devrec), "Unable to get IRQ");
goto err_irq;
}
return 0;
err_irq:
err_read_reg:
ieee802154_unregister_device(devrec->dev);
err_register_device:
ieee802154_free_device(devrec->dev);
err_alloc_dev:
kfree(devrec->buf);
err_buf:
kfree(devrec);
err_devrec:
return ret;
}
static int mrf24j40_remove(struct spi_device *spi)
{
struct mrf24j40 *devrec = dev_get_drvdata(&spi->dev);
dev_dbg(printdev(devrec), "remove\n");
free_irq(spi->irq, devrec);
flush_work(&devrec->irqwork); /* TODO: Is this the right call? */
ieee802154_unregister_device(devrec->dev);
ieee802154_free_device(devrec->dev);
/* TODO: Will ieee802154_free_device() wait until ->xmit() is
* complete? */
/* Clean up the SPI stuff. */
dev_set_drvdata(&spi->dev, NULL);
kfree(devrec->buf);
kfree(devrec);
return 0;
}
static const struct spi_device_id mrf24j40_ids[] = {
{ "mrf24j40", 0 },
{ "mrf24j40ma", 0 },
{ },
};
MODULE_DEVICE_TABLE(spi, mrf24j40_ids);
static struct spi_driver mrf24j40_driver = {
.driver = {
.name = "mrf24j40",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.id_table = mrf24j40_ids,
.probe = mrf24j40_probe,
.remove = mrf24j40_remove,
};
static int __init mrf24j40_init(void)
{
return spi_register_driver(&mrf24j40_driver);
}
static void __exit mrf24j40_exit(void)
{
spi_unregister_driver(&mrf24j40_driver);
}
module_init(mrf24j40_init);
module_exit(mrf24j40_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alan Ott");
MODULE_DESCRIPTION("MRF24J40 SPI 802.15.4 Controller Driver");