This patch adds the driver support for the cc2520 radio.

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 <var...@cdac.in>
---
 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..c951958
--- /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 <var...@cdac.in>
+ *                   Md.Jamal Mohiuddin <mjmohiud...@cdac.in>
+ *                   P Sowjanya <sowjan...@cdac.in>
+ *
+ * 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_dbg(&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 (!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 <var...@cdac.in>");
+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..85b8ee6
--- /dev/null
+++ b/include/linux/spi/cc2520.h
@@ -0,0 +1,26 @@
+/* Header file for cc2520 radio driver
+ *
+ * Copyright (C) 2014 Varka Bhadram <var...@cdac.in>
+ *                    Md.Jamal Mohiuddin <mjmohiud...@cdac.in>
+ *                    P Sowjanya <sowjan...@cdac.in>
+ *
+ * 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


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