Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1263 insertions, 0 deletions

diff --git a/drivers/net/ieee802154/cc2520.c b/drivers/net/ieee802154/cc2520.c
new file mode 100644
index 000000000..0c89d3edf
--- /dev/null
+++ b/drivers/net/ieee802154/cc2520.c
@@ -0,0 +1,1263 @@
+/* Driver for TI CC2520 802.15.4 Wireless-PAN Networking controller
+ *
+ * Copyright (C) 2014 Varka Bhadram <varkab@cdac.in>
+ *		      Md.Jamal Mohiuddin <mjmohiuddin@cdac.in>
+ *		      P Sowjanya <sowjanyap@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/of_gpio.h>
+#include <linux/ieee802154.h>
+#include <linux/crc-ccitt.h>
+#include <asm/unaligned.h>
+
+#include <net/mac802154.h>
+#include <net/cfg802154.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	BIT(7)
+#define	CC2520_STATUS_RSSI_VALID	BIT(6)
+#define	CC2520_STATUS_TX_UNDERFLOW	BIT(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
+
+/* CC2520_FRMFILT0 */
+#define FRMFILT0_FRAME_FILTER_EN	BIT(0)
+#define FRMFILT0_PAN_COORDINATOR	BIT(1)
+
+/* CC2520_FRMCTRL0 */
+#define FRMCTRL0_AUTOACK		BIT(5)
+#define FRMCTRL0_AUTOCRC		BIT(6)
+
+/* CC2520_FRMCTRL1 */
+#define FRMCTRL1_SET_RXENMASK_ON_TX	BIT(0)
+#define FRMCTRL1_IGNORE_TX_UNDERF	BIT(1)
+
+/* Driver private information */
+struct cc2520_private {
+	struct spi_device *spi;		/* SPI device structure */
+	struct ieee802154_hw *hw;	/* IEEE-802.15.4 device */
+	u8 *buf;			/* SPI TX/Rx data buffer */
+	struct mutex buffer_mutex;	/* SPI buffer mutex */
+	bool is_tx;			/* Flag for sync b/w Tx and Rx */
+	bool amplified;			/* Flag for CC2591 */
+	int fifo_pin;			/* FIFO GPIO pin number */
+	struct work_struct fifop_irqwork;/* Workqueue for FIFOP */
+	spinlock_t lock;		/* Lock for is_tx*/
+	struct completion tx_complete;	/* Work completion for Tx */
+	bool promiscuous;               /* Flag for promiscuous mode */
+};
+
+/* 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_write_ram(struct cc2520_private *priv, u16 reg, u8 len, u8 *data)
+{
+	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,
+		.tx_buf = data,
+	};
+
+	mutex_lock(&priv->buffer_mutex);
+	priv->buf[xfer_head.len++] = (CC2520_CMD_MEMORY_WRITE |
+						((reg >> 8) & 0xff));
+	priv->buf[xfer_head.len++] = reg & 0xff;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfer_head, &msg);
+	spi_message_add_tail(&xfer_buf, &msg);
+
+	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_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 pkt_len, u8 *data, u8 len)
+{
+	int status;
+
+	/* length byte must include FCS even
+	 * if it is calculated in the hardware
+	 */
+	int len_byte = pkt_len;
+
+	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)
+{
+	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]);
+
+	mutex_unlock(&priv->buffer_mutex);
+
+	return status;
+}
+
+static int cc2520_start(struct ieee802154_hw *hw)
+{
+	return cc2520_cmd_strobe(hw->priv, CC2520_CMD_SRXON);
+}
+
+static void cc2520_stop(struct ieee802154_hw *hw)
+{
+	cc2520_cmd_strobe(hw->priv, CC2520_CMD_SRFOFF);
+}
+
+static int
+cc2520_tx(struct ieee802154_hw *hw, struct sk_buff *skb)
+{
+	struct cc2520_private *priv = hw->priv;
+	unsigned long flags;
+	int rc;
+	u8 status = 0;
+	u8 pkt_len;
+
+	/* In promiscuous mode we disable AUTOCRC so we can get the raw CRC
+	 * values on RX. This means we need to manually add the CRC on TX.
+	 */
+	if (priv->promiscuous) {
+		u16 crc = crc_ccitt(0, skb->data, skb->len);
+
+		put_unaligned_le16(crc, skb_put(skb, 2));
+		pkt_len = skb->len;
+	} else {
+		pkt_len = skb->len + 2;
+	}
+
+	rc = cc2520_cmd_strobe(priv, CC2520_CMD_SFLUSHTX);
+	if (rc)
+		goto err_tx;
+
+	rc = cc2520_write_txfifo(priv, pkt_len, 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);
+	WARN_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;
+
+	/* Read single length byte from the radio. */
+	cc2520_read_rxfifo(priv, &len, bytes);
+
+	if (!ieee802154_is_valid_psdu_len(len)) {
+		/* Corrupted frame received, clear frame buffer by
+		 * reading entire buffer.
+		 */
+		dev_dbg(&priv->spi->dev, "corrupted frame received\n");
+		len = IEEE802154_MTU;
+	}
+
+	skb = dev_alloc_skb(len);
+	if (!skb)
+		return -ENOMEM;
+
+	if (cc2520_read_rxfifo(priv, skb_put(skb, len), len)) {
+		dev_dbg(&priv->spi->dev, "frame reception failed\n");
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
+	/* In promiscuous mode, we configure the radio to include the
+	 * CRC (AUTOCRC==0) and we pass on the packet unconditionally. If not
+	 * in promiscuous mode, we check the CRC here, but leave the
+	 * RSSI/LQI/CRC_OK bytes as they will get removed in the mac layer.
+	 */
+	if (!priv->promiscuous) {
+		bool crc_ok;
+
+		/* Check if the CRC is valid. With AUTOCRC set, the most
+		 * significant bit of the last byte returned from the CC2520
+		 * is CRC_OK flag. See section 20.3.4 of the datasheet.
+		 */
+		crc_ok = skb->data[len - 1] & BIT(7);
+
+		/* If we failed CRC drop the packet in the driver layer. */
+		if (!crc_ok) {
+			dev_dbg(&priv->spi->dev, "CRC check failed\n");
+			kfree_skb(skb);
+			return -EINVAL;
+		}
+
+		/* To calculate LQI, the lower 7 bits of the last byte (the
+		 * correlation value provided by the radio) must be scaled to
+		 * the range 0-255. According to section 20.6, the correlation
+		 * value ranges from 50-110. Ideally this would be calibrated
+		 * per hardware design, but we use roughly the datasheet values
+		 * to get close enough while avoiding floating point.
+		 */
+		lqi = skb->data[len - 1] & 0x7f;
+		if (lqi < 50)
+			lqi = 50;
+		else if (lqi > 113)
+			lqi = 113;
+		lqi = (lqi - 50) * 4;
+	}
+
+	ieee802154_rx_irqsafe(priv->hw, skb, lqi);
+
+	dev_vdbg(&priv->spi->dev, "RXFIFO: %x %x\n", len, lqi);
+
+	return 0;
+}
+
+static int
+cc2520_ed(struct ieee802154_hw *hw, u8 *level)
+{
+	struct cc2520_private *priv = hw->priv;
+	u8 status = 0xff;
+	u8 rssi;
+	int ret;
+
+	ret = cc2520_read_register(priv, CC2520_RSSISTAT, &status);
+	if (ret)
+		return ret;
+
+	if (status != RSSI_VALID)
+		return -EINVAL;
+
+	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 0;
+}
+
+static int
+cc2520_set_channel(struct ieee802154_hw *hw, u8 page, u8 channel)
+{
+	struct cc2520_private *priv = hw->priv;
+	int ret;
+
+	dev_dbg(&priv->spi->dev, "trying to set channel\n");
+
+	WARN_ON(page != 0);
+	WARN_ON(channel < CC2520_MINCHANNEL);
+	WARN_ON(channel > CC2520_MAXCHANNEL);
+
+	ret = cc2520_write_register(priv, CC2520_FREQCTRL,
+				    11 + 5 * (channel - 11));
+
+	return ret;
+}
+
+static int
+cc2520_filter(struct ieee802154_hw *hw,
+	      struct ieee802154_hw_addr_filt *filt, unsigned long changed)
+{
+	struct cc2520_private *priv = hw->priv;
+	int ret = 0;
+
+	if (changed & IEEE802154_AFILT_PANID_CHANGED) {
+		u16 panid = le16_to_cpu(filt->pan_id);
+
+		dev_vdbg(&priv->spi->dev, "%s called for pan id\n", __func__);
+		ret = cc2520_write_ram(priv, CC2520RAM_PANID,
+				       sizeof(panid), (u8 *)&panid);
+	}
+
+	if (changed & IEEE802154_AFILT_IEEEADDR_CHANGED) {
+		dev_vdbg(&priv->spi->dev,
+			 "%s called for IEEE addr\n", __func__);
+		ret = cc2520_write_ram(priv, CC2520RAM_IEEEADDR,
+				       sizeof(filt->ieee_addr),
+				       (u8 *)&filt->ieee_addr);
+	}
+
+	if (changed & IEEE802154_AFILT_SADDR_CHANGED) {
+		u16 addr = le16_to_cpu(filt->short_addr);
+
+		dev_vdbg(&priv->spi->dev, "%s called for saddr\n", __func__);
+		ret = cc2520_write_ram(priv, CC2520RAM_SHORTADDR,
+				       sizeof(addr), (u8 *)&addr);
+	}
+
+	if (changed & IEEE802154_AFILT_PANC_CHANGED) {
+		u8 frmfilt0;
+
+		dev_vdbg(&priv->spi->dev,
+			 "%s called for panc change\n", __func__);
+
+		cc2520_read_register(priv, CC2520_FRMFILT0, &frmfilt0);
+
+		if (filt->pan_coord)
+			frmfilt0 |= FRMFILT0_PAN_COORDINATOR;
+		else
+			frmfilt0 &= ~FRMFILT0_PAN_COORDINATOR;
+
+		ret = cc2520_write_register(priv, CC2520_FRMFILT0, frmfilt0);
+	}
+
+	return ret;
+}
+
+static inline int cc2520_set_tx_power(struct cc2520_private *priv, s32 mbm)
+{
+	u8 power;
+
+	switch (mbm) {
+	case 500:
+		power = 0xF7;
+		break;
+	case 300:
+		power = 0xF2;
+		break;
+	case 200:
+		power = 0xAB;
+		break;
+	case 100:
+		power = 0x13;
+		break;
+	case 0:
+		power = 0x32;
+		break;
+	case -200:
+		power = 0x81;
+		break;
+	case -400:
+		power = 0x88;
+		break;
+	case -700:
+		power = 0x2C;
+		break;
+	case -1800:
+		power = 0x03;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return cc2520_write_register(priv, CC2520_TXPOWER, power);
+}
+
+static inline int cc2520_cc2591_set_tx_power(struct cc2520_private *priv,
+					     s32 mbm)
+{
+	u8 power;
+
+	switch (mbm) {
+	case 1700:
+		power = 0xF9;
+		break;
+	case 1600:
+		power = 0xF0;
+		break;
+	case 1400:
+		power = 0xA0;
+		break;
+	case 1100:
+		power = 0x2C;
+		break;
+	case -100:
+		power = 0x03;
+		break;
+	case -800:
+		power = 0x01;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return cc2520_write_register(priv, CC2520_TXPOWER, power);
+}
+
+#define CC2520_MAX_TX_POWERS 0x8
+static const s32 cc2520_powers[CC2520_MAX_TX_POWERS + 1] = {
+	500, 300, 200, 100, 0, -200, -400, -700, -1800,
+};
+
+#define CC2520_CC2591_MAX_TX_POWERS 0x5
+static const s32 cc2520_cc2591_powers[CC2520_CC2591_MAX_TX_POWERS + 1] = {
+	1700, 1600, 1400, 1100, -100, -800,
+};
+
+static int
+cc2520_set_txpower(struct ieee802154_hw *hw, s32 mbm)
+{
+	struct cc2520_private *priv = hw->priv;
+
+	if (!priv->amplified)
+		return cc2520_set_tx_power(priv, mbm);
+
+	return cc2520_cc2591_set_tx_power(priv, mbm);
+}
+
+static int
+cc2520_set_promiscuous_mode(struct ieee802154_hw *hw, bool on)
+{
+	struct cc2520_private *priv = hw->priv;
+	u8 frmfilt0;
+
+	dev_dbg(&priv->spi->dev, "%s : mode %d\n", __func__, on);
+
+	priv->promiscuous = on;
+
+	cc2520_read_register(priv, CC2520_FRMFILT0, &frmfilt0);
+
+	if (on) {
+		/* Disable automatic ACK, automatic CRC, and frame filtering. */
+		cc2520_write_register(priv, CC2520_FRMCTRL0, 0);
+		frmfilt0 &= ~FRMFILT0_FRAME_FILTER_EN;
+	} else {
+		cc2520_write_register(priv, CC2520_FRMCTRL0, FRMCTRL0_AUTOACK |
+							     FRMCTRL0_AUTOCRC);
+		frmfilt0 |= FRMFILT0_FRAME_FILTER_EN;
+	}
+	return cc2520_write_register(priv, CC2520_FRMFILT0, frmfilt0);
+}
+
+static const struct ieee802154_ops cc2520_ops = {
+	.owner = THIS_MODULE,
+	.start = cc2520_start,
+	.stop = cc2520_stop,
+	.xmit_sync = cc2520_tx,
+	.ed = cc2520_ed,
+	.set_channel = cc2520_set_channel,
+	.set_hw_addr_filt = cc2520_filter,
+	.set_txpower = cc2520_set_txpower,
+	.set_promiscuous_mode = cc2520_set_promiscuous_mode,
+};
+
+static int cc2520_register(struct cc2520_private *priv)
+{
+	int ret = -ENOMEM;
+
+	priv->hw = ieee802154_alloc_hw(sizeof(*priv), &cc2520_ops);
+	if (!priv->hw)
+		goto err_ret;
+
+	priv->hw->priv = priv;
+	priv->hw->parent = &priv->spi->dev;
+	priv->hw->extra_tx_headroom = 0;
+	ieee802154_random_extended_addr(&priv->hw->phy->perm_extended_addr);
+
+	/* We do support only 2.4 Ghz */
+	priv->hw->phy->supported.channels[0] = 0x7FFF800;
+	priv->hw->flags = IEEE802154_HW_TX_OMIT_CKSUM | IEEE802154_HW_AFILT |
+			  IEEE802154_HW_PROMISCUOUS;
+
+	priv->hw->phy->flags = WPAN_PHY_FLAG_TXPOWER;
+
+	if (!priv->amplified) {
+		priv->hw->phy->supported.tx_powers = cc2520_powers;
+		priv->hw->phy->supported.tx_powers_size = ARRAY_SIZE(cc2520_powers);
+		priv->hw->phy->transmit_power = priv->hw->phy->supported.tx_powers[4];
+	} else {
+		priv->hw->phy->supported.tx_powers = cc2520_cc2591_powers;
+		priv->hw->phy->supported.tx_powers_size = ARRAY_SIZE(cc2520_cc2591_powers);
+		priv->hw->phy->transmit_power = priv->hw->phy->supported.tx_powers[0];
+	}
+
+	priv->hw->phy->current_channel = 11;
+
+	dev_vdbg(&priv->spi->dev, "registered cc2520\n");
+	ret = ieee802154_register_hw(priv->hw);
+	if (ret)
+		goto err_free_device;
+
+	return 0;
+
+err_free_device:
+	ieee802154_free_hw(priv->hw);
+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_get_platform_data(struct spi_device *spi,
+				    struct cc2520_platform_data *pdata)
+{
+	struct device_node *np = spi->dev.of_node;
+	struct cc2520_private *priv = spi_get_drvdata(spi);
+
+	if (!np) {
+		struct cc2520_platform_data *spi_pdata = spi->dev.platform_data;
+
+		if (!spi_pdata)
+			return -ENOENT;
+		*pdata = *spi_pdata;
+		priv->fifo_pin = pdata->fifo;
+		return 0;
+	}
+
+	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);
+
+	/* CC2591 front end for CC2520 */
+	if (of_property_read_bool(np, "amplified"))
+		priv->amplified = true;
+
+	return 0;
+}
+
+static int cc2520_hw_init(struct cc2520_private *priv)
+{
+	u8 status = 0, state = 0xff;
+	int ret;
+	int timeout = 100;
+	struct cc2520_platform_data pdata;
+
+	ret = cc2520_get_platform_data(priv->spi, &pdata);
+	if (ret)
+		goto err_ret;
+
+	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 brought up\n");
+
+	/* If the CC2520 is connected to a CC2591 amplifier, we must both
+	 * configure GPIOs on the CC2520 to correctly configure the CC2591
+	 * and change a couple settings of the CC2520 to work with the
+	 * amplifier. See section 8 page 17 of TI application note AN065.
+	 * http://www.ti.com/lit/an/swra229a/swra229a.pdf
+	 */
+	if (priv->amplified) {
+		ret = cc2520_write_register(priv, CC2520_AGCCTRL1, 0x16);
+		if (ret)
+			goto err_ret;
+
+		ret = cc2520_write_register(priv, CC2520_GPIOCTRL0, 0x46);
+		if (ret)
+			goto err_ret;
+
+		ret = cc2520_write_register(priv, CC2520_GPIOCTRL5, 0x47);
+		if (ret)
+			goto err_ret;
+
+		ret = cc2520_write_register(priv, CC2520_GPIOPOLARITY, 0x1e);
+		if (ret)
+			goto err_ret;
+
+		ret = cc2520_write_register(priv, CC2520_TXCTRL, 0xc1);
+		if (ret)
+			goto err_ret;
+	} else {
+		ret = cc2520_write_register(priv, CC2520_AGCCTRL1, 0x11);
+		if (ret)
+			goto err_ret;
+	}
+
+	/* Registers default value: section 28.1 in Datasheet */
+
+	/* Set the CCA threshold to -50 dBm. This seems to have been copied
+	 * from the TinyOS CC2520 driver and is much higher than the -84 dBm
+	 * threshold suggested in the datasheet.
+	 */
+	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_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;
+
+	/* Configure registers correctly for this driver. */
+	ret = cc2520_write_register(priv, CC2520_FRMCTRL1,
+				    FRMCTRL1_SET_RXENMASK_ON_TX |
+				    FRMCTRL1_IGNORE_TX_UNDERF);
+	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 int cc2520_probe(struct spi_device *spi)
+{
+	struct cc2520_private *priv;
+	struct cc2520_platform_data pdata;
+	int ret;
+
+	priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	spi_set_drvdata(spi, priv);
+
+	ret = cc2520_get_platform_data(spi, &pdata);
+	if (ret < 0) {
+		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)
+		return -ENOMEM;
+
+	mutex_init(&priv->buffer_mutex);
+	INIT_WORK(&priv->fifop_irqwork, cc2520_fifop_irqwork);
+	spin_lock_init(&priv->lock);
+	init_completion(&priv->tx_complete);
+
+	/* Assumption that CC2591 is not connected */
+	priv->amplified = false;
+
+	/* 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);
+	usleep_range(100, 150);
+
+	gpio_set_value(pdata.reset, HIGH);
+	usleep_range(200, 250);
+
+	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);
+	return ret;
+}
+
+static int cc2520_remove(struct spi_device *spi)
+{
+	struct cc2520_private *priv = spi_get_drvdata(spi);
+
+	mutex_destroy(&priv->buffer_mutex);
+	flush_work(&priv->fifop_irqwork);
+
+	ieee802154_unregister_hw(priv->hw);
+	ieee802154_free_hw(priv->hw);
+
+	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",
+		.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 <varkab@cdac.in>");
+MODULE_DESCRIPTION("CC2520 Transceiver Driver");
+MODULE_LICENSE("GPL v2");