This series adds the driver support for TI cc2520 radio.
also devicetree bindings for the driver.
changes since v1:
- improverment in gpio setup
- changed len pointer to len variable
-
Varka Bhadram (3):
ieee802154: cc2520: adds driver for TI CC2520 radio
ieee802154: cc2520: add driver to kernel build system
devicetree: add devicetree bindings for cc2520 driver
.../devicetree/bindings/net/ieee802154/cc2520.txt | 26 +
drivers/net/ieee802154/Kconfig | 11 +
drivers/net/ieee802154/Makefile | 1 +
drivers/net/ieee802154/cc2520.c | 968 ++++++++++++++++++++
include/linux/spi/cc2520.h | 26 +
5 files changed, 1032 insertions(+)
create mode 100644 Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
create mode 100644 drivers/net/ieee802154/cc2520.c
create mode 100644 include/linux/spi/cc2520.h
--
1.7.9.5
Driver support:
- Tx and Rx of IEEE-802.15.4 packets.
- Energy Detection on channel.
- Setting the Channel for the radio. [b/w 11 - 26 channels]
- Start and Stop the radio.
Signed-off-by: Varka Bhadram <[email protected]>
---
drivers/net/ieee802154/cc2520.c | 968 +++++++++++++++++++++++++++++++++++++++
include/linux/spi/cc2520.h | 26 ++
2 files changed, 994 insertions(+)
create mode 100644 drivers/net/ieee802154/cc2520.c
create mode 100644 include/linux/spi/cc2520.h
diff --git a/drivers/net/ieee802154/cc2520.c b/drivers/net/ieee802154/cc2520.c
new file mode 100644
index 0000000..29ac8d8
--- /dev/null
+++ b/drivers/net/ieee802154/cc2520.c
@@ -0,0 +1,968 @@
+/* Driver for TI CC2520 802.15.4 Wireless-PAN Networking controller
+ *
+ * Copyright (C) 2014 Varka Bhadram <[email protected]>
+ * Md.Jamal Mohiuddin <[email protected]>
+ * P Sowjanya <[email protected]>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/cc2520.h>
+#include <linux/workqueue.h>
+#include <linux/interrupt.h>
+
+#include <linux/skbuff.h>
+
+#include <linux/pinctrl/consumer.h>
+
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
+
+#include <net/mac802154.h>
+#include <net/wpan-phy.h>
+
+#define SPI_COMMAND_BUFFER 3
+#define HIGH 1
+#define LOW 0
+#define STATE_IDLE 0
+#define RSSI_VALID 0
+#define RSSI_OFFSET 78
+
+#define CC2520_RAM_SIZE 640
+#define CC2520_FIFO_SIZE 128
+
+#define CC2520RAM_TXFIFO 0x100,
+#define CC2520RAM_RXFIFO 0x180,
+#define CC2520RAM_IEEEADDR 0x3EA,
+#define CC2520RAM_PANID 0x3F2,
+#define CC2520RAM_SHORTADDR 0x3F4,
+
+#define CC2520_FREG_MASK 0x3F
+
+/*status byte values */
+#define CC2520_STATUS_XOSC32M_STABLE (1 << 7)
+#define CC2520_STATUS_RSSI_VALID (1 << 6)
+#define CC2520_STATUS_TX_UNDERFLOW (1 << 3)
+
+/*IEEE 802.15.4 defined constants (2.4 GHz logical channels) */
+#define CC2520_MINCHANNEL 11
+#define CC2520_MAXCHANNEL 26
+#define CC2520_CHANNEL_SPACING 5
+
+/*command strobes*/
+#define CC2520_CMD_SNOP 0x00
+#define CC2520_CMD_IBUFLD 0x02
+#define CC2520_CMD_SIBUFEX 0x03
+#define CC2520_CMD_SSAMPLECCA 0x04
+#define CC2520_CMD_SRES 0x0f
+#define CC2520_CMD_MEMORY_MASK 0x0f
+#define CC2520_CMD_MEMORY_READ 0x10
+#define CC2520_CMD_MEMORY_WRITE 0x20
+#define CC2520_CMD_RXBUF 0x30
+#define CC2520_CMD_RXBUFCP 0x38
+#define CC2520_CMD_RXBUFMOV 0x32
+#define CC2520_CMD_TXBUF 0x3A
+#define CC2520_CMD_TXBUFCP 0x3E
+#define CC2520_CMD_RANDOM 0x3C
+#define CC2520_CMD_SXOSCON 0x40
+#define CC2520_CMD_STXCAL 0x41
+#define CC2520_CMD_SRXON 0x42
+#define CC2520_CMD_STXON 0x43
+#define CC2520_CMD_STXONCCA 0x44
+#define CC2520_CMD_SRFOFF 0x45
+#define CC2520_CMD_SXOSCOFF 0x46
+#define CC2520_CMD_SFLUSHRX 0x47
+#define CC2520_CMD_SFLUSHTX 0x48
+#define CC2520_CMD_SACK 0x49
+#define CC2520_CMD_SACKPEND 0x4A
+#define CC2520_CMD_SNACK 0x4B
+#define CC2520_CMD_SRXMASKBITSET 0x4C
+#define CC2520_CMD_SRXMASKBITCLR 0x4D
+#define CC2520_CMD_RXMASKAND 0x4E
+#define CC2520_CMD_RXMASKOR 0x4F
+#define CC2520_CMD_MEMCP 0x50
+#define CC2520_CMD_MEMCPR 0x52
+#define CC2520_CMD_MEMXCP 0x54
+#define CC2520_CMD_MEMXWR 0x56
+#define CC2520_CMD_BCLR 0x58
+#define CC2520_CMD_BSET 0x59
+#define CC2520_CMD_CTR_UCTR 0x60
+#define CC2520_CMD_CBCMAC 0x64
+#define CC2520_CMD_UCBCMAC 0x66
+#define CC2520_CMD_CCM 0x68
+#define CC2520_CMD_UCCM 0x6A
+#define CC2520_CMD_ECB 0x70
+#define CC2520_CMD_ECBO 0x72
+#define CC2520_CMD_ECBX 0x74
+#define CC2520_CMD_INC 0x78
+#define CC2520_CMD_ABORT 0x7F
+#define CC2520_CMD_REGISTER_READ 0x80
+#define CC2520_CMD_REGISTER_WRITE 0xC0
+
+/* status registers */
+#define CC2520_CHIPID 0x40
+#define CC2520_VERSION 0x42
+#define CC2520_EXTCLOCK 0x44
+#define CC2520_MDMCTRL0 0x46
+#define CC2520_MDMCTRL1 0x47
+#define CC2520_FREQEST 0x48
+#define CC2520_RXCTRL 0x4A
+#define CC2520_FSCTRL 0x4C
+#define CC2520_FSCAL0 0x4E
+#define CC2520_FSCAL1 0x4F
+#define CC2520_FSCAL2 0x50
+#define CC2520_FSCAL3 0x51
+#define CC2520_AGCCTRL0 0x52
+#define CC2520_AGCCTRL1 0x53
+#define CC2520_AGCCTRL2 0x54
+#define CC2520_AGCCTRL3 0x55
+#define CC2520_ADCTEST0 0x56
+#define CC2520_ADCTEST1 0x57
+#define CC2520_ADCTEST2 0x58
+#define CC2520_MDMTEST0 0x5A
+#define CC2520_MDMTEST1 0x5B
+#define CC2520_DACTEST0 0x5C
+#define CC2520_DACTEST1 0x5D
+#define CC2520_ATEST 0x5E
+#define CC2520_DACTEST2 0x5F
+#define CC2520_PTEST0 0x60
+#define CC2520_PTEST1 0x61
+#define CC2520_RESERVED 0x62
+#define CC2520_DPUBIST 0x7A
+#define CC2520_ACTBIST 0x7C
+#define CC2520_RAMBIST 0x7E
+
+/*frame registers*/
+#define CC2520_FRMFILT0 0x00
+#define CC2520_FRMFILT1 0x01
+#define CC2520_SRCMATCH 0x02
+#define CC2520_SRCSHORTEN0 0x04
+#define CC2520_SRCSHORTEN1 0x05
+#define CC2520_SRCSHORTEN2 0x06
+#define CC2520_SRCEXTEN0 0x08
+#define CC2520_SRCEXTEN1 0x09
+#define CC2520_SRCEXTEN2 0x0A
+#define CC2520_FRMCTRL0 0x0C
+#define CC2520_FRMCTRL1 0x0D
+#define CC2520_RXENABLE0 0x0E
+#define CC2520_RXENABLE1 0x0F
+#define CC2520_EXCFLAG0 0x10
+#define CC2520_EXCFLAG1 0x11
+#define CC2520_EXCFLAG2 0x12
+#define CC2520_EXCMASKA0 0x14
+#define CC2520_EXCMASKA1 0x15
+#define CC2520_EXCMASKA2 0x16
+#define CC2520_EXCMASKB0 0x18
+#define CC2520_EXCMASKB1 0x19
+#define CC2520_EXCMASKB2 0x1A
+#define CC2520_EXCBINDX0 0x1C
+#define CC2520_EXCBINDX1 0x1D
+#define CC2520_EXCBINDY0 0x1E
+#define CC2520_EXCBINDY1 0x1F
+#define CC2520_GPIOCTRL0 0x20
+#define CC2520_GPIOCTRL1 0x21
+#define CC2520_GPIOCTRL2 0x22
+#define CC2520_GPIOCTRL3 0x23
+#define CC2520_GPIOCTRL4 0x24
+#define CC2520_GPIOCTRL5 0x25
+#define CC2520_GPIOPOLARITY 0x26
+#define CC2520_GPIOCTRL 0x28
+#define CC2520_DPUCON 0x2A
+#define CC2520_DPUSTAT 0x2C
+#define CC2520_FREQCTRL 0x2E
+#define CC2520_FREQTUNE 0x2F
+#define CC2520_TXPOWER 0x30
+#define CC2520_TXCTRL 0x31
+#define CC2520_FSMSTAT0 0x32
+#define CC2520_FSMSTAT1 0x33
+#define CC2520_FIFOPCTRL 0x34
+#define CC2520_FSMCTRL 0x35
+#define CC2520_CCACTRL0 0x36
+#define CC2520_CCACTRL1 0x37
+#define CC2520_RSSI 0x38
+#define CC2520_RSSISTAT 0x39
+#define CC2520_RXFIRST 0x3C
+#define CC2520_RXFIFOCNT 0x3E
+#define CC2520_TXFIFOCNT 0x3F
+
+/* Driver private information */
+struct cc2520_private {
+ struct spi_device *spi; /* spi device structure */
+ struct ieee802154_dev *dev; /* Ieee802.15.4 device */
+ u8 *buf; /* SPI TX/Rx data buffer */
+ struct mutex buffer_mutex; /* SPI buffer mutex */
+ unsigned is_tx:1; /* Flag for sync b/w Tx and Rx */
+ int fifo_pin; /* FIFO GPIO pin number */
+ struct work_struct fifop_irqwork;/* Workqueue for FIFOP */
+ spinlock_t lock; /* Spin lock */
+ struct completion tx_complete; /* Work completion for Tx */
+};
+
+/* Generic Functions */
+static int
+cc2520_cmd_strobe(struct cc2520_private *priv, u8 cmd)
+{
+ int ret;
+ u8 status = 0xff;
+ struct spi_message msg;
+ struct spi_transfer xfer = {
+ .len = 0,
+ .tx_buf = priv->buf,
+ .rx_buf = priv->buf,
+ };
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+
+ mutex_lock(&priv->buffer_mutex);
+ priv->buf[xfer.len++] = cmd;
+ dev_vdbg(&priv->spi->dev,
+ "command strobe buf[0] = %02x\n",
+ priv->buf[0]);
+
+ ret = spi_sync(priv->spi, &msg);
+ if (!ret)
+ status = priv->buf[0];
+ dev_vdbg(&priv->spi->dev,
+ "buf[0] = %02x\n", priv->buf[0]);
+ mutex_unlock(&priv->buffer_mutex);
+
+ return ret;
+}
+
+static int
+cc2520_get_status(struct cc2520_private *priv, u8 *status)
+{
+ int ret;
+ struct spi_message msg;
+ struct spi_transfer xfer = {
+ .len = 0,
+ .tx_buf = priv->buf,
+ .rx_buf = priv->buf,
+ };
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+
+ mutex_lock(&priv->buffer_mutex);
+ priv->buf[xfer.len++] = CC2520_CMD_SNOP;
+ dev_vdbg(&priv->spi->dev,
+ "get status command buf[0] = %02x\n", priv->buf[0]);
+
+ ret = spi_sync(priv->spi, &msg);
+ if (!ret)
+ *status = priv->buf[0];
+ dev_vdbg(&priv->spi->dev,
+ "buf[0] = %02x\n", priv->buf[0]);
+ mutex_unlock(&priv->buffer_mutex);
+
+ return ret;
+}
+
+static int
+cc2520_write_register(struct cc2520_private *priv, u8 reg, u8 value)
+{
+ int status;
+ struct spi_message msg;
+ struct spi_transfer xfer = {
+ .len = 0,
+ .tx_buf = priv->buf,
+ .rx_buf = priv->buf,
+ };
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+
+ mutex_lock(&priv->buffer_mutex);
+
+ if (reg <= CC2520_FREG_MASK) {
+ priv->buf[xfer.len++] = CC2520_CMD_REGISTER_WRITE | reg;
+ priv->buf[xfer.len++] = value;
+ } else {
+ priv->buf[xfer.len++] = CC2520_CMD_MEMORY_WRITE;
+ priv->buf[xfer.len++] = reg;
+ priv->buf[xfer.len++] = value;
+ }
+ status = spi_sync(priv->spi, &msg);
+ if (msg.status)
+ status = msg.status;
+
+ mutex_unlock(&priv->buffer_mutex);
+
+ return status;
+}
+
+static int
+cc2520_read_register(struct cc2520_private *priv, u8 reg, u8 *data)
+{
+ int status;
+ struct spi_message msg;
+ struct spi_transfer xfer1 = {
+ .len = 0,
+ .tx_buf = priv->buf,
+ .rx_buf = priv->buf,
+ };
+
+ struct spi_transfer xfer2 = {
+ .len = 1,
+ .rx_buf = data,
+ };
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer1, &msg);
+ spi_message_add_tail(&xfer2, &msg);
+
+ mutex_lock(&priv->buffer_mutex);
+ priv->buf[xfer1.len++] = CC2520_CMD_MEMORY_READ;
+ priv->buf[xfer1.len++] = reg;
+
+ status = spi_sync(priv->spi, &msg);
+ dev_dbg(&priv->spi->dev,
+ "spi status = %d\n", status);
+ if (msg.status)
+ status = msg.status;
+
+ mutex_unlock(&priv->buffer_mutex);
+
+ return status;
+}
+
+static int
+cc2520_write_txfifo(struct cc2520_private *priv, u8 *data, u8 len)
+{
+ int status;
+
+ /*
+ *length byte must include FCS even
+ *if it is calculated in the hardware
+ */
+ int len_byte = len + 2;
+
+ struct spi_message msg;
+
+ struct spi_transfer xfer_head = {
+ .len = 0,
+ .tx_buf = priv->buf,
+ .rx_buf = priv->buf,
+ };
+ struct spi_transfer xfer_len = {
+ .len = 1,
+ .tx_buf = &len_byte,
+ };
+ struct spi_transfer xfer_buf = {
+ .len = len,
+ .tx_buf = data,
+ };
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer_head, &msg);
+ spi_message_add_tail(&xfer_len, &msg);
+ spi_message_add_tail(&xfer_buf, &msg);
+
+ mutex_lock(&priv->buffer_mutex);
+ priv->buf[xfer_head.len++] = CC2520_CMD_TXBUF;
+ dev_vdbg(&priv->spi->dev,
+ "TX_FIFO cmd buf[0] = %02x\n", priv->buf[0]);
+
+ status = spi_sync(priv->spi, &msg);
+ dev_vdbg(&priv->spi->dev, "status = %d\n", status);
+ if (msg.status)
+ status = msg.status;
+ dev_vdbg(&priv->spi->dev, "status = %d\n", status);
+ dev_vdbg(&priv->spi->dev, "buf[0] = %02x\n", priv->buf[0]);
+ mutex_unlock(&priv->buffer_mutex);
+
+ return status;
+}
+
+static int
+cc2520_read_rxfifo(struct cc2520_private *priv, u8 *data, u8 len, u8 *lqi)
+{
+ int status;
+ struct spi_message msg;
+
+ struct spi_transfer xfer_head = {
+ .len = 0,
+ .tx_buf = priv->buf,
+ .rx_buf = priv->buf,
+ };
+ struct spi_transfer xfer_buf = {
+ .len = len,
+ .rx_buf = data,
+ };
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer_head, &msg);
+ spi_message_add_tail(&xfer_buf, &msg);
+
+ mutex_lock(&priv->buffer_mutex);
+ priv->buf[xfer_head.len++] = CC2520_CMD_RXBUF;
+
+ dev_vdbg(&priv->spi->dev, "read rxfifo buf[0] = %02x\n", priv->buf[0]);
+ dev_vdbg(&priv->spi->dev, "buf[1] = %02x\n", priv->buf[1]);
+
+ status = spi_sync(priv->spi, &msg);
+ dev_vdbg(&priv->spi->dev, "status = %d\n", status);
+ if (msg.status)
+ status = msg.status;
+ dev_vdbg(&priv->spi->dev, "status = %d\n", status);
+ dev_vdbg(&priv->spi->dev,
+ "return status buf[0] = %02x\n", priv->buf[0]);
+ dev_vdbg(&priv->spi->dev, "length buf[1] = %02x\n", priv->buf[1]);
+
+ *lqi = data[priv->buf[1] - 1] & 0x7f;
+
+ mutex_unlock(&priv->buffer_mutex);
+
+ return status;
+}
+
+static int cc2520_start(struct ieee802154_dev *dev)
+{
+ return cc2520_cmd_strobe(dev->priv, CC2520_CMD_SRXON);
+}
+
+static void cc2520_stop(struct ieee802154_dev *dev)
+{
+ cc2520_cmd_strobe(dev->priv, CC2520_CMD_SRFOFF);
+}
+
+static int
+cc2520_tx(struct ieee802154_dev *dev, struct sk_buff *skb)
+{
+ struct cc2520_private *priv = dev->priv;
+ unsigned long flags;
+ int rc;
+ u8 status = 0;
+
+ rc = cc2520_cmd_strobe(priv, CC2520_CMD_SFLUSHTX);
+ if (rc)
+ goto err_tx;
+
+ rc = cc2520_write_txfifo(priv, skb->data, skb->len);
+ if (rc)
+ goto err_tx;
+
+ rc = cc2520_get_status(priv, &status);
+ if (rc)
+ goto err_tx;
+
+ if (status & CC2520_STATUS_TX_UNDERFLOW) {
+ dev_err(&priv->spi->dev, "cc2520 tx underflow exception\n");
+ goto err_tx;
+ }
+
+ spin_lock_irqsave(&priv->lock, flags);
+ BUG_ON(priv->is_tx);
+ priv->is_tx = 1;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ rc = cc2520_cmd_strobe(priv, CC2520_CMD_STXONCCA);
+ if (rc)
+ goto err;
+
+ rc = wait_for_completion_interruptible(&priv->tx_complete);
+ if (rc < 0)
+ goto err;
+
+ cc2520_cmd_strobe(priv, CC2520_CMD_SFLUSHTX);
+ cc2520_cmd_strobe(priv, CC2520_CMD_SRXON);
+
+ return rc;
+err:
+ spin_lock_irqsave(&priv->lock, flags);
+ priv->is_tx = 0;
+ spin_unlock_irqrestore(&priv->lock, flags);
+err_tx:
+ return rc;
+}
+
+
+static int cc2520_rx(struct cc2520_private *priv)
+{
+ u8 len = 0, lqi = 0, bytes = 1;
+ struct sk_buff *skb;
+
+ cc2520_read_rxfifo(priv, &len, bytes, &lqi);
+
+ skb = alloc_skb(len, GFP_KERNEL);
+ if (!skb)
+ return -ENOMEM;
+
+ cc2520_read_rxfifo(priv, skb_put(skb, len), len, &lqi);
+ if (len < 2) {
+ kfree_skb(skb);
+ return -EINVAL;
+ }
+
+ skb_trim(skb, skb->len - 2);
+
+ ieee802154_rx_irqsafe(priv->dev, skb, lqi);
+
+ dev_vdbg(&priv->spi->dev, "RXFIFO: %x %x\n", len, lqi);
+
+ return 0;
+}
+
+static int
+cc2520_ed(struct ieee802154_dev *dev, u8 *level)
+{
+ struct cc2520_private *priv = dev->priv;
+ u8 status = 0xff;
+ u8 rssi;
+ int ret;
+
+ ret = cc2520_read_register(priv , CC2520_RSSISTAT, &status);
+ if (ret)
+ return ret;
+
+ if (status != RSSI_VALID) {
+ ret = -EINVAL;
+ return ret;
+ }
+
+ ret = cc2520_read_register(priv , CC2520_RSSI, &rssi);
+ if (ret)
+ return ret;
+
+ /* level = RSSI(rssi) - OFFSET [dBm] : offset is 76dBm*/
+ *level = rssi - RSSI_OFFSET;
+
+ return ret;
+}
+
+static int
+cc2520_set_channel(struct ieee802154_dev *dev, int page, int channel)
+{
+ struct cc2520_private *priv = dev->priv;
+ int ret;
+
+ might_sleep();
+ dev_dbg(&priv->spi->dev, "trying to set channel\n");
+
+ BUG_ON(page != 0);
+ BUG_ON(channel < CC2520_MINCHANNEL);
+ BUG_ON(channel > CC2520_MAXCHANNEL);
+
+ ret = cc2520_write_register(priv, CC2520_FREQCTRL,
+ 11 + 5*(channel - 11));
+
+ return ret;
+}
+
+static struct ieee802154_ops cc2520_ops = {
+ .owner = THIS_MODULE,
+ .start = cc2520_start,
+ .stop = cc2520_stop,
+ .xmit = cc2520_tx,
+ .ed = cc2520_ed,
+ .set_channel = cc2520_set_channel,
+};
+
+static int cc2520_register(struct cc2520_private *priv)
+{
+ int ret = -ENOMEM;
+
+ priv->dev = ieee802154_alloc_device(sizeof(*priv), &cc2520_ops);
+ if (!priv->dev)
+ goto err_ret;
+
+ priv->dev->priv = priv;
+ priv->dev->parent = &priv->spi->dev;
+ priv->dev->extra_tx_headroom = 0;
+
+ /* We do support only 2.4 Ghz */
+ priv->dev->phy->channels_supported[0] = 0x7FFF800;
+ priv->dev->flags = IEEE802154_HW_OMIT_CKSUM;
+
+ dev_vdbg(&priv->spi->dev, "registered cc2520\n");
+ ret = ieee802154_register_device(priv->dev);
+ if (ret)
+ goto err_free_device;
+
+ return 0;
+
+err_free_device:
+ ieee802154_free_device(priv->dev);
+err_ret:
+ return ret;
+}
+
+static void cc2520_fifop_irqwork(struct work_struct *work)
+{
+ struct cc2520_private *priv
+ = container_of(work, struct cc2520_private, fifop_irqwork);
+
+ dev_dbg(&priv->spi->dev, "fifop interrupt received\n");
+
+ if (gpio_get_value(priv->fifo_pin))
+ cc2520_rx(priv);
+ else
+ dev_err(&priv->spi->dev, "rxfifo overflow\n");
+
+ cc2520_cmd_strobe(priv, CC2520_CMD_SFLUSHRX);
+ cc2520_cmd_strobe(priv, CC2520_CMD_SFLUSHRX);
+}
+
+static irqreturn_t cc2520_fifop_isr(int irq, void *data)
+{
+ struct cc2520_private *priv = data;
+
+ schedule_work(&priv->fifop_irqwork);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t cc2520_sfd_isr(int irq, void *data)
+{
+ struct cc2520_private *priv = data;
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->is_tx) {
+ priv->is_tx = 0;
+ spin_unlock_irqrestore(&priv->lock, flags);
+ dev_dbg(&priv->spi->dev, "SFD for TX\n");
+ complete(&priv->tx_complete);
+ } else {
+ spin_unlock_irqrestore(&priv->lock, flags);
+ dev_dbg(&priv->spi->dev, "SFD for RX\n");
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int cc2520_hw_init(struct cc2520_private *priv)
+{
+ u8 status = 0, state = 0xff;
+ int ret;
+ int timeout = 100;
+
+ ret = cc2520_read_register(priv, CC2520_FSMSTAT1, &state);
+ if (ret)
+ goto err_ret;
+
+ if (state != STATE_IDLE)
+ return -EINVAL;
+
+ do {
+ ret = cc2520_get_status(priv, &status);
+ if (ret)
+ goto err_ret;
+
+ if (timeout-- <= 0) {
+ dev_err(&priv->spi->dev, "oscillator start failed!\n");
+ return ret;
+ }
+ udelay(1);
+ } while (!(status & CC2520_STATUS_XOSC32M_STABLE));
+
+ dev_vdbg(&priv->spi->dev, "oscillator successfully brought up\n");
+
+ /*Registers default value: section 28.1 in Datasheet*/
+ ret = cc2520_write_register(priv, CC2520_TXPOWER, 0xF7);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_CCACTRL0, 0x1A);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_MDMCTRL0, 0x85);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_MDMCTRL1, 0x14);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_RXCTRL, 0x3f);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_FSCTRL, 0x5a);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_FSCAL1, 0x2b);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_AGCCTRL1, 0x11);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_ADCTEST0, 0x10);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_ADCTEST1, 0x0e);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_ADCTEST2, 0x03);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_FRMCTRL0, 0x60);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_FRMCTRL1, 0x03);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_FRMFILT0, 0x00);
+ if (ret)
+ goto err_ret;
+
+ ret = cc2520_write_register(priv, CC2520_FIFOPCTRL, 127);
+ if (ret)
+ goto err_ret;
+
+ return 0;
+
+err_ret:
+ return ret;
+}
+
+static struct cc2520_platform_data *
+cc2520_get_platform_data(struct spi_device *spi)
+{
+ struct cc2520_platform_data *pdata;
+ struct device_node __maybe_unused *np = spi->dev.of_node;
+ struct cc2520_private *priv = spi_get_drvdata(spi);
+
+ if (!IS_ENABLED(CONFIG_OF) || !np)
+ return spi->dev.platform_data;
+
+ pdata = devm_kzalloc(&spi->dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ goto done;
+
+ pdata->fifo = of_get_named_gpio(np, "fifo-gpio", 0);
+ priv->fifo_pin = pdata->fifo;
+
+ pdata->fifop = of_get_named_gpio(np, "fifop-gpio", 0);
+
+ pdata->sfd = of_get_named_gpio(np, "sfd-gpio", 0);
+ pdata->cca = of_get_named_gpio(np, "cca-gpio", 0);
+ pdata->vreg = of_get_named_gpio(np, "vreg-gpio", 0);
+ pdata->reset = of_get_named_gpio(np, "reset-gpio", 0);
+
+ spi->dev.platform_data = pdata;
+
+done:
+ return pdata;
+}
+
+static int cc2520_probe(struct spi_device *spi)
+{
+ struct cc2520_private *priv;
+ struct pinctrl *pinctrl;
+ struct cc2520_platform_data *pdata;
+ struct device_node __maybe_unused *np = spi->dev.of_node;
+ int ret;
+
+ priv = devm_kzalloc(&spi->dev,
+ sizeof(struct cc2520_private), GFP_KERNEL);
+ if (!priv) {
+ ret = -ENOMEM;
+ goto err_ret;
+ }
+
+ spi_set_drvdata(spi, priv);
+
+ pinctrl = devm_pinctrl_get_select_default(&spi->dev);
+ if (IS_ERR(pinctrl))
+ dev_warn(&spi->dev,
+ "pinctrl pins are not configured from the driver");
+
+ pdata = cc2520_get_platform_data(spi);
+ if (!pdata) {
+ dev_err(&spi->dev, "no platform data\n");
+ return -EINVAL;
+ }
+
+ priv->spi = spi;
+
+ priv->buf = devm_kzalloc(&spi->dev,
+ SPI_COMMAND_BUFFER, GFP_KERNEL);
+ if (!priv->buf) {
+ ret = -ENOMEM;
+ goto err_ret;
+ }
+
+ mutex_init(&priv->buffer_mutex);
+ INIT_WORK(&priv->fifop_irqwork, cc2520_fifop_irqwork);
+ spin_lock_init(&priv->lock);
+ init_completion(&priv->tx_complete);
+
+ /* Request all the gpio's */
+ if (!gpio_is_valid(pdata->fifo)) {
+ dev_err(&spi->dev, "fifo gpio is not valid\n");
+ ret = -EINVAL;
+ goto err_hw_init;
+ }
+
+ ret = devm_gpio_request_one(&spi->dev, pdata->fifo,
+ GPIOF_IN, "fifo");
+ if (ret)
+ goto err_hw_init;
+
+ if (!gpio_is_valid(pdata->cca)) {
+ dev_err(&spi->dev, "cca gpio is not valid\n");
+ ret = -EINVAL;
+ goto err_hw_init;
+ }
+
+ ret = devm_gpio_request_one(&spi->dev, pdata->cca,
+ GPIOF_IN, "cca");
+ if (ret)
+ goto err_hw_init;
+
+ if (!gpio_is_valid(pdata->fifop)) {
+ dev_err(&spi->dev, "fifop gpio is not valid\n");
+ ret = -EINVAL;
+ goto err_hw_init;
+ }
+
+ ret = devm_gpio_request_one(&spi->dev, pdata->fifop,
+ GPIOF_IN, "fifop");
+ if (ret)
+ goto err_hw_init;
+
+ if (!gpio_is_valid(pdata->sfd)) {
+ dev_err(&spi->dev, "sfd gpio is not valid\n");
+ ret = -EINVAL;
+ goto err_hw_init;
+ }
+
+ ret = devm_gpio_request_one(&spi->dev, pdata->sfd,
+ GPIOF_IN, "sfd");
+ if (ret)
+ goto err_hw_init;
+
+ if (!gpio_is_valid(pdata->reset)) {
+ dev_err(&spi->dev, "reset gpio is not valid\n");
+ ret = -EINVAL;
+ goto err_hw_init;
+ }
+
+ ret = devm_gpio_request_one(&spi->dev, pdata->reset,
+ GPIOF_OUT_INIT_LOW, "reset");
+ if (ret)
+ goto err_hw_init;
+
+ if (!gpio_is_valid(pdata->vreg)) {
+ dev_err(&spi->dev, "vreg gpio is not valid\n");
+ ret = -EINVAL;
+ goto err_hw_init;
+ }
+
+ ret = devm_gpio_request_one(&spi->dev, pdata->vreg,
+ GPIOF_OUT_INIT_LOW, "vreg");
+ if (ret)
+ goto err_hw_init;
+
+
+ gpio_set_value(pdata->vreg, HIGH);
+ udelay(100);
+
+ gpio_set_value(pdata->reset, HIGH);
+ udelay(200);
+
+ ret = cc2520_hw_init(priv);
+ if (ret)
+ goto err_hw_init;
+
+ /* Set up fifop interrupt */
+ ret = devm_request_irq(&spi->dev,
+ gpio_to_irq(pdata->fifop),
+ cc2520_fifop_isr,
+ IRQF_TRIGGER_RISING,
+ dev_name(&spi->dev),
+ priv);
+ if (ret) {
+ dev_err(&spi->dev, "could not get fifop irq\n");
+ goto err_hw_init;
+ }
+
+ /* Set up sfd interrupt */
+ ret = devm_request_irq(&spi->dev,
+ gpio_to_irq(pdata->sfd),
+ cc2520_sfd_isr,
+ IRQF_TRIGGER_FALLING,
+ dev_name(&spi->dev),
+ priv);
+ if (ret) {
+ dev_err(&spi->dev, "could not get sfd irq\n");
+ goto err_hw_init;
+ }
+
+ ret = cc2520_register(priv);
+ if (ret)
+ goto err_hw_init;
+
+ return 0;
+
+err_hw_init:
+ mutex_destroy(&priv->buffer_mutex);
+ flush_work(&priv->fifop_irqwork);
+
+err_ret:
+ return ret;
+}
+
+static int cc2520_remove(struct spi_device *spi)
+{
+ struct cc2520_private *priv = spi_get_drvdata(spi);
+
+ ieee802154_unregister_device(priv->dev);
+ ieee802154_free_device(priv->dev);
+
+ mutex_destroy(&priv->buffer_mutex);
+ flush_work(&priv->fifop_irqwork);
+
+ return 0;
+}
+
+static const struct spi_device_id cc2520_ids[] = {
+ {"cc2520", },
+ {},
+};
+MODULE_DEVICE_TABLE(spi, cc2520_ids);
+
+static const struct of_device_id cc2520_of_ids[] = {
+ {.compatible = "ti,cc2520", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, cc2520_of_ids);
+
+/*SPI driver structure*/
+static struct spi_driver cc2520_driver = {
+ .driver = {
+ .name = "cc2520",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(cc2520_of_ids),
+ },
+ .id_table = cc2520_ids,
+ .probe = cc2520_probe,
+ .remove = cc2520_remove,
+};
+module_spi_driver(cc2520_driver);
+
+MODULE_AUTHOR("Varka Bhadram <[email protected]>");
+MODULE_DESCRIPTION("CC2520 Transceiver Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/spi/cc2520.h b/include/linux/spi/cc2520.h
new file mode 100644
index 0000000..56ce81e
--- /dev/null
+++ b/include/linux/spi/cc2520.h
@@ -0,0 +1,26 @@
+/* Header file cc2520 driver
+ *
+ * Copyright (C) 2014 Varka Bhadram <[email protected]>
+ * Md.Jamal Mohiuddin <[email protected]>
+ * P Sowjanya <[email protected]>
+ *
+ * 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.
+ *
+ */
+
+#ifndef __CC2520_H
+#define __CC2520_H
+
+struct cc2520_platform_data {
+ int fifo;
+ int fifop;
+ int cca;
+ int sfd;
+ int reset;
+ int vreg;
+};
+
+#endif
--
1.7.9.5
devicetree bindings for cc2520 radio driver.
Signed-off-by: Varka Bhadram <[email protected]>
---
.../devicetree/bindings/net/ieee802154/cc2520.txt | 26 ++++++++++++++++++++
1 file changed, 26 insertions(+)
create mode 100644 Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
diff --git a/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt b/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
new file mode 100644
index 0000000..f0a749d
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
@@ -0,0 +1,26 @@
+CC2520 IEEE 802.15.4 Compatible Radio
+
+Required properties:
+ - compatible: should be "ti,cc2520"
+ - spi-max-frequency: maximal bus speed (8000000), should be set to 4000000 depends
+ sync or async operation mode
+ - reg: the chipselect index
+ - mode: SPI mode
+Example:
+
+ cc2520@0 {
+ compatible = "ti,cc2520";
+ reg = <0>;
+ spi-max-frequency = <4000000>;
+ mode = <1>;
+
+ pinctrl-names = "default";
+ pinctrl-0 = <&cc2520_cape_pins>; /*GPIO pin muxing details*/
+
+ fifo-gpio = <&gpio1 18 0>;
+ fifop-gpio = <&gpio1 19 0>;
+ sfd-gpio = <&gpio1 13 0>;
+ cca-gpio = <&gpio1 16 0>;
+ vreg-gpio = <&gpio0 31 0>;
+ reset-gpio = <&gpio1 12 0>;
+ };
--
1.7.9.5
Signed-off-by: Varka Bhadram <[email protected]>
---
drivers/net/ieee802154/Kconfig | 11 +++++++++++
drivers/net/ieee802154/Makefile | 1 +
2 files changed, 12 insertions(+)
diff --git a/drivers/net/ieee802154/Kconfig b/drivers/net/ieee802154/Kconfig
index 3e89bea..680422f 100644
--- a/drivers/net/ieee802154/Kconfig
+++ b/drivers/net/ieee802154/Kconfig
@@ -51,3 +51,14 @@ config IEEE802154_MRF24J40
This driver can also be built as a module. To do so, say M here.
the module will be called 'mrf24j40'.
+
+config IEEE802154_CC2520
+ depends on IEEE802154_DRIVERS && MAC802154
+ tristate "cc2520 transceiver driver"
+ depends on SPI
+ ---help---
+ Say Y here to enable the CC2520 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 'cc2520'.
diff --git a/drivers/net/ieee802154/Makefile b/drivers/net/ieee802154/Makefile
index abb0c08..655cb95 100644
--- a/drivers/net/ieee802154/Makefile
+++ b/drivers/net/ieee802154/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_IEEE802154_FAKEHARD) += fakehard.o
obj-$(CONFIG_IEEE802154_FAKELB) += fakelb.o
obj-$(CONFIG_IEEE802154_AT86RF230) += at86rf230.o
obj-$(CONFIG_IEEE802154_MRF24J40) += mrf24j40.o
+obj-$(CONFIG_IEEE802154_CC2520) += cc2520.o
--
1.7.9.5
On Wed, Jun 18, 2014 at 06:16:05AM +0100, Varka Bhadram wrote:
> devicetree bindings for cc2520 radio driver.
>
> Signed-off-by: Varka Bhadram <[email protected]>
> ---
> .../devicetree/bindings/net/ieee802154/cc2520.txt | 26 ++++++++++++++++++++
> 1 file changed, 26 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
>
> diff --git a/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt b/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
> new file mode 100644
> index 0000000..f0a749d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
> @@ -0,0 +1,26 @@
> +CC2520 IEEE 802.15.4 Compatible Radio
> +
> +Required properties:
> + - compatible: should be "ti,cc2520"
> + - spi-max-frequency: maximal bus speed (8000000), should be set to 4000000 depends
> + sync or async operation mode
> + - reg: the chipselect index
> + - mode: SPI mode
What exactly is this property? It doesn't seem to be used by the driver,
the example is opaque, and this doesn't seem to match any existing
bindings (a grep for "mode" in Documentation/devicetree/bindings/spi
only found me a string "mode" property).
The example has several properties (the GPIOs and pinctrl) not listed
here...
Mark.
> +Example:
> +
> + cc2520@0 {
> + compatible = "ti,cc2520";
> + reg = <0>;
> + spi-max-frequency = <4000000>;
> + mode = <1>;
> +
> + pinctrl-names = "default";
> + pinctrl-0 = <&cc2520_cape_pins>; /*GPIO pin muxing details*/
> +
> + fifo-gpio = <&gpio1 18 0>;
> + fifop-gpio = <&gpio1 19 0>;
> + sfd-gpio = <&gpio1 13 0>;
> + cca-gpio = <&gpio1 16 0>;
> + vreg-gpio = <&gpio0 31 0>;
> + reset-gpio = <&gpio1 12 0>;
> + };
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe devicetree" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
On Wed, Jun 18, 2014 at 06:16:03AM +0100, Varka Bhadram wrote:
> Driver support:
> - Tx and Rx of IEEE-802.15.4 packets.
> - Energy Detection on channel.
> - Setting the Channel for the radio. [b/w 11 - 26 channels]
> - Start and Stop the radio.
>
> Signed-off-by: Varka Bhadram <[email protected]>
> ---
> drivers/net/ieee802154/cc2520.c | 968 +++++++++++++++++++++++++++++++++++++++
> include/linux/spi/cc2520.h | 26 ++
> 2 files changed, 994 insertions(+)
> create mode 100644 drivers/net/ieee802154/cc2520.c
> create mode 100644 include/linux/spi/cc2520.h
[...]
> +static struct cc2520_platform_data *
> +cc2520_get_platform_data(struct spi_device *spi)
> +{
> + struct cc2520_platform_data *pdata;
> + struct device_node __maybe_unused *np = spi->dev.of_node;
> + struct cc2520_private *priv = spi_get_drvdata(spi);
> +
> + if (!IS_ENABLED(CONFIG_OF) || !np)
> + return spi->dev.platform_data;
Surely "if (!np)" is good enough?
[...]
> +static int cc2520_probe(struct spi_device *spi)
> +{
> + struct cc2520_private *priv;
> + struct pinctrl *pinctrl;
> + struct cc2520_platform_data *pdata;
> + struct device_node __maybe_unused *np = spi->dev.of_node;
This looks to be definitely unused rather than __maybe_unused. There are
no other occuences of "np" in this function.
Mark.
Hi,
On 06/18/2014 02:35 PM, Mark Rutland wrote:
> On Wed, Jun 18, 2014 at 06:16:05AM +0100, Varka Bhadram wrote:
>> devicetree bindings for cc2520 radio driver.
>>
>> Signed-off-by: Varka Bhadram <[email protected]>
>> ---
>> .../devicetree/bindings/net/ieee802154/cc2520.txt | 26 ++++++++++++++++++++
>> 1 file changed, 26 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
>>
>> diff --git a/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt b/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
>> new file mode 100644
>> index 0000000..f0a749d
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/net/ieee802154/cc2520.txt
>> @@ -0,0 +1,26 @@
>> +CC2520 IEEE 802.15.4 Compatible Radio
>> +
>> +Required properties:
>> + - compatible: should be "ti,cc2520"
>> + - spi-max-frequency: maximal bus speed (8000000), should be set to 4000000 depends
>> + sync or async operation mode
>> + - reg: the chipselect index
>> + - mode: SPI mode
> What exactly is this property? It doesn't seem to be used by the driver,
> the example is opaque, and this doesn't seem to match any existing
> bindings (a grep for "mode" in Documentation/devicetree/bindings/spi
> only found me a string "mode" property).
>
> The example has several properties (the GPIOs and pinctrl) not listed
> here...
Previously is used this 'mode' property to set the SPI mode. but i am not using now. I will remove it.
And also i will add the optional properties GPIO and pinctrl in next version.
Thanks for comments.
-Varka Bhadram.
>
> Mark.
>
>> +Example:
>> +
>> + cc2520@0 {
>> + compatible = "ti,cc2520";
>> + reg = <0>;
>> + spi-max-frequency = <4000000>;
>> + mode = <1>;
>> +
>> + pinctrl-names = "default";
>> + pinctrl-0 = <&cc2520_cape_pins>; /*GPIO pin muxing details*/
>> +
>> + fifo-gpio = <&gpio1 18 0>;
>> + fifop-gpio = <&gpio1 19 0>;
>> + sfd-gpio = <&gpio1 13 0>;
>> + cca-gpio = <&gpio1 16 0>;
>> + vreg-gpio = <&gpio0 31 0>;
>> + reset-gpio = <&gpio1 12 0>;
>> + };
>> --
>> 1.7.9.5
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe devicetree" in
>> the body of a message to [email protected]
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
On Wed, Jun 18, 2014 at 10:26:16AM +0100, Varka Bhadram wrote:
> +static int cc2520_probe(struct spi_device *spi)
> +{
> + struct cc2520_private *priv;
> + struct pinctrl *pinctrl;
> + struct cc2520_platform_data *pdata;
> + struct device_node __maybe_unused *np = spi->dev.of_node;
>
> This looks to be definitely unused rather than __maybe_unused. There are
> no other occuences of "np" in this function.
>
> This macro defined like this.
> #define __maybe_unused __attribute__((unused))
Sure, but that's irrelevant. There's absolutely no point in this
variable existing at all, and it can simply disappear.
Mark.
On 06/18/2014 03:25 PM, Mark Rutland wrote:
> On Wed, Jun 18, 2014 at 10:26:16AM +0100, Varka Bhadram wrote:
>> +static int cc2520_probe(struct spi_device *spi)
>> +{
>> + struct cc2520_private *priv;
>> + struct pinctrl *pinctrl;
>> + struct cc2520_platform_data *pdata;
>> + struct device_node __maybe_unused *np = spi->dev.of_node;
>>
>> This looks to be definitely unused rather than __maybe_unused. There are
>> no other occuences of "np" in this function.
>>
>> This macro defined like this.
>> #define __maybe_unused __attribute__((unused))
> Sure, but that's irrelevant. There's absolutely no point in this
> variable existing at all, and it can simply disappear.
>
> Mark.
If we don't use that macro the compiler triggers warnings saying that: warning: unused variable ?np? [-Wunused-variable]
Varka Bhadram
On Wed, Jun 18, 2014 at 12:13:06PM +0100, Varka Bhadram wrote:
> On 06/18/2014 03:25 PM, Mark Rutland wrote:
> > On Wed, Jun 18, 2014 at 10:26:16AM +0100, Varka Bhadram wrote:
> >> +static int cc2520_probe(struct spi_device *spi)
> >> +{
> >> + struct cc2520_private *priv;
> >> + struct pinctrl *pinctrl;
> >> + struct cc2520_platform_data *pdata;
> >> + struct device_node __maybe_unused *np = spi->dev.of_node;
> >>
> >> This looks to be definitely unused rather than __maybe_unused. There are
> >> no other occuences of "np" in this function.
> >>
> >> This macro defined like this.
> >> #define __maybe_unused __attribute__((unused))
> > Sure, but that's irrelevant. There's absolutely no point in this
> > variable existing at all, and it can simply disappear.
> >
> > Mark.
>
> If we don't use that macro the compiler triggers warnings saying that: warning: unused variable ‘np’ [-Wunused-variable]
Then drop the _variable_, not just the annotation.
Mark.