Hi,

just several trivial notes:

2012/6/14 Alan Ott <a...@signal11.us>:
> Driver for the Microchip MRF24J40 802.15.4 WPAN module.
>
> ---
>
> Changes in v3:
>  changed MAX_SPEED logic.
>  change all __u8 and __u16 to u8 and u16
>  make read_short_reg() return status and take value pointer as parameter.
>  change read_long_reg() to return status and take value pointer as a 
> parameter.
>  eliminate unnecessary casting.
>  Fixed debugging printouts.
>  Added additional TODO question
> ---
>  drivers/ieee802154/Kconfig    |   11 +
>  drivers/ieee802154/Makefile   |    1 +
>  drivers/ieee802154/mrf24j40.c |  784 
> +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 796 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/ieee802154/mrf24j40.c
>
> diff --git a/drivers/ieee802154/Kconfig b/drivers/ieee802154/Kconfig
> index b1f0ce8..7c8fde7 100644
> --- a/drivers/ieee802154/Kconfig
> +++ b/drivers/ieee802154/Kconfig
> @@ -49,3 +49,14 @@ config IEEE802154_ADF7242
>        tristate "ADF7242 transceiver driver"
>        depends on IEEE802154_DRIVERS && MAC802154
>        depends on SPI
> +
> +config IEEE802154_MRF24J40
> +       tristate "Microchip MRF24J40 transceiver driver"
> +       depends on IEEE802154_DRIVERS && MAC802154
> +       depends on SPI
> +       ---help---
> +         Say Y here to enable the MRF24J20 SPI 802.15.4 wireless
> +         controller.
> +
> +         This driver can also be built as a module. To do so, say M here.
> +         the module will be called 'mrf24j40'.
> diff --git a/drivers/ieee802154/Makefile b/drivers/ieee802154/Makefile
> index 54efc02..f060d51 100644
> --- a/drivers/ieee802154/Makefile
> +++ b/drivers/ieee802154/Makefile
> @@ -4,3 +4,4 @@ obj-$(CONFIG_IEEE802154_SERIAL) += serial.o
>  obj-$(CONFIG_IEEE802154_AT86RF230) += at86rf230.o
>  obj-$(CONFIG_IEEE802154_CC2420) += cc2420.o
>  obj-$(CONFIG_IEEE802154_ADF7242) += adf7242.o
> +obj-$(CONFIG_IEEE802154_MRF24J40) += mrf24j40.o
> diff --git a/drivers/ieee802154/mrf24j40.c b/drivers/ieee802154/mrf24j40.c
> new file mode 100644
> index 0000000..a610c8a
> --- /dev/null
> +++ b/drivers/ieee802154/mrf24j40.c
> @@ -0,0 +1,784 @@
> +/*
> + * Driver for Microchip MRF24J40 802.15.4 Wireless-PAN Networking controller
> + *
> + * Copyright (C) 2012 Alan Ott <a...@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/kernel.h>
> +#include <linux/spi/spi.h>
> +#include <linux/irq.h>
> +#include <linux/interrupt.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +
> +#include <linux/netdevice.h>
> +#include <linux/skbuff.h>
> +#include <net/af_ieee802154.h>
> +#include <net/ieee802154.h>
> +#include <net/ieee802154_netdev.h>
> +#include <net/nl802154.h>
> +#include <net/wpan-phy.h>
> +#include <net/mac802154.h>
> +

Do you really need all these headers?


> +/* 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 */
> +

Why does the first reg-section contain 2-digits values and here I see 3-digits?
If the value should be 1 bytes size please use something like: 0xff,
if 2 bytes: 0xffff.

> +/** Device configuration **/

Please use the univocal comment style. For example:
1 - line comment: /* blablabla */
More lines comment:
/* blablalba
   blablabla
 */

And please drop all the "//" entries.

> +/* 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))
> +
> +/* Device Private Data */
> +struct mrf24j40 {
> +       struct spi_device *spi;
> +       struct ieee802154_dev *dev;
> +
> +       struct mutex mutex;

very obvious variable name... :)

> +       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->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);
> +               goto out;

Hmmm, what does this goto mean?

> +       }
> +
> +out:
> +       mutex_unlock(&devrec->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->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);
> +               goto out;

again and below

> +       } else
> +               *val = devrec->buf[1];
> +
> +out:
> +       mutex_unlock(&devrec->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->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);
> +               goto out;
> +       } else
> +               *value = devrec->buf[2];
> +
> +out:
> +       mutex_unlock(&devrec->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->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);
> +               goto out;
> +       }
> +
> +out:
> +       mutex_unlock(&devrec->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,
> +       };
> +
> +       BUG_ON(length > 126);

Do really think that it's a good idea to crash all the kernel if you
got bad data?

> +
> +       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->mutex);
> +       devrec->buf[0] = cmd >> 8 & 0xff;

braces and may be some extra empty lines to make code more readable

> +       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");
> +               goto out;
> +       }
> +
> +out:
> +       mutex_unlock(&devrec->mutex);
> +       return ret;
> +}
> +
> +static int mrf24j40_read_rx_buf(struct mrf24j40 *devrec,
> +                               u8 *data, u8 *len, u8 *lqi)
> +{
> +       u8 val;
> +       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. */
> +       ret = read_long_reg(devrec, REG_RX_FIFO, &val);
> +       if (ret)
> +               goto out;
> +
> +       if (val > 143) {

What's the magic number?

> +               /* RX FIFO on the MRF24J40 is 144 bytes long. One byte is
> +                  used at the beginning of the buffer for the length.  */
> +               dev_err(printdev(devrec), "Invalid length read from device. 
> Performing short read.\n");
> +               val = 143;
> +       }
> +
> +       if (val > *len) {
> +               /* We read 2 bytes more than the length at 0x300. */
> +               dev_err(printdev(devrec), "Buffer not big enough. Performing 
> short read\n");
> +               val = *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 = val;
> +
> +       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 = val;
> +
> +#ifdef DEBUG
> +       {
> +               int i;
> +               printk(KERN_DEBUG "%d bytes received\n", *len);
> +               printk(KERN_DEBUG "  ");
> +               for (i = 0; i < *len; i++)
> +                       printk("%02hhx ", data[i]);
> +               printk("\n");
> +               printk(KERN_DEBUG "    %02hhx %02hhx\n",
> +                       lqi_rssi[0], lqi_rssi[1]);
> +       }
> +#endif

Use print_hex_dump() hex

> +
> +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);
> +
> +       BUG_ON(page != 0);
> +       BUG_ON(channel < MRF24J40_CHAN_MIN);
> +       BUG_ON(channel > MRF24J40_CHAN_MAX);

again

> +
> +       /* 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(192); /* per datasheet */

magic number

> +
> +       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_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_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_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_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 = 144; /* size of RX FIFO buffer */
> +       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;
> +
> +       /* Check for TX complete */
> +       ret = read_short_reg(devrec, REG_INTSTAT, &intstat);
> +       if (ret)
> +               goto out;
> +
> +       if (intstat & 0x1)
> +               complete(&devrec->tx_complete);
> +
> +       /* Check for Rx */
> +       if (intstat & 0x8)
> +               mrf24j40_handle_rx(devrec);
> +
> +       //TODO: What is this?
> +       read_short_reg(devrec, REG_INTSTAT, &intstat);
> +
> +out:
> +       enable_irq(devrec->spi->irq);
> +}
> +
> +static int __devinit 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->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 */
> +
> +       // TODO: Shouldn't priv_size be set to zero in the call to
> +       // ieee802154_alloc_device()?  Other drivers do it this way, but
> +       // mac802154/main.c seems to suggest zero is the right answer
> +       // instead.

aghr...

> +       devrec->dev = ieee802154_alloc_device(sizeof(*devrec), &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 __devexit 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_sync(&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 = __devexit_p(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");
> --
> 1.7.0.4
>

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