drivers/iio/gyro/adxrs450.c - kernel/msm-4.9 - Gitiles

 /*
  * ADXRS450/ADXRS453 Digital Output Gyroscope Driver
  *
  * Copyright 2011 Analog Devices Inc.
  *
  * Licensed under the GPL-2.
  */

 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/spi/spi.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
 #include <linux/list.h>
 #include <linux/module.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>

 #define ADXRS450_STARTUP_DELAY	50 /* ms */

 /* The MSB for the spi commands */
 #define ADXRS450_SENSOR_DATA    (0x20 << 24)
 #define ADXRS450_WRITE_DATA	(0x40 << 24)
 #define ADXRS450_READ_DATA	(0x80 << 24)

 #define ADXRS450_RATE1	0x00	/* Rate Registers */
 #define ADXRS450_TEMP1	0x02	/* Temperature Registers */
 #define ADXRS450_LOCST1	0x04	/* Low CST Memory Registers */
 #define ADXRS450_HICST1	0x06	/* High CST Memory Registers */
 #define ADXRS450_QUAD1	0x08	/* Quad Memory Registers */
 #define ADXRS450_FAULT1	0x0A	/* Fault Registers */
 #define ADXRS450_PID1	0x0C	/* Part ID Register 1 */
 #define ADXRS450_SNH	0x0E	/* Serial Number Registers, 4 bytes */
 #define ADXRS450_SNL	0x10
 #define ADXRS450_DNC1	0x12	/* Dynamic Null Correction Registers */
 /* Check bits */
 #define ADXRS450_P	0x01
 #define ADXRS450_CHK	0x02
 #define ADXRS450_CST	0x04
 #define ADXRS450_PWR	0x08
 #define ADXRS450_POR	0x10
 #define ADXRS450_NVM	0x20
 #define ADXRS450_Q	0x40
 #define ADXRS450_PLL	0x80
 #define ADXRS450_UV	0x100
 #define ADXRS450_OV	0x200
 #define ADXRS450_AMP	0x400
 #define ADXRS450_FAIL	0x800

 #define ADXRS450_WRERR_MASK	(0x7 << 29)

 #define ADXRS450_MAX_RX 4
 #define ADXRS450_MAX_TX 4

 #define ADXRS450_GET_ST(a)	((a >> 26) & 0x3)

 enum {
 	ID_ADXRS450,
 	ID_ADXRS453,
 };

 /**
  * struct adxrs450_state - device instance specific data
  * @us:			actual spi_device
  * @buf_lock:		mutex to protect tx and rx
  * @tx:			transmit buffer
  * @rx:			receive buffer
  **/
 struct adxrs450_state {
 	struct spi_device	*us;
 	struct mutex		buf_lock;
 	__be32			tx ____cacheline_aligned;
 	__be32			rx;

 };

 /**
  * adxrs450_spi_read_reg_16() - read 2 bytes from a register pair
  * @indio_dev: device associated with child of actual iio_dev
  * @reg_address: the address of the lower of the two registers, which should be
  *	an even address, the second register's address is reg_address + 1.
  * @val: somewhere to pass back the value read
  **/
 static int adxrs450_spi_read_reg_16(struct iio_dev *indio_dev,
 				    u8 reg_address,
 				    u16 *val)
 {
 	struct spi_message msg;
 	struct adxrs450_state *st = iio_priv(indio_dev);
 	u32 tx;
 	int ret;
 	struct spi_transfer xfers[] = {
 		{
 			.tx_buf = &st->tx,
 			.bits_per_word = 8,
 			.len = sizeof(st->tx),
 			.cs_change = 1,
 		}, {
 			.rx_buf = &st->rx,
 			.bits_per_word = 8,
 			.len = sizeof(st->rx),
 		},
 	};

 	mutex_lock(&st->buf_lock);
 	tx = ADXRS450_READ_DATA | (reg_address << 17);

 	if (!(hweight32(tx) & 1))
 		tx |= ADXRS450_P;

 	st->tx = cpu_to_be32(tx);
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfers[0], &msg);
 	spi_message_add_tail(&xfers[1], &msg);
 	ret = spi_sync(st->us, &msg);
 	if (ret) {
 		dev_err(&st->us->dev, "problem while reading 16 bit register 0x%02x\n",
 				reg_address);
 		goto error_ret;
 	}

 	*val = (be32_to_cpu(st->rx) >> 5) & 0xFFFF;

 error_ret:
 	mutex_unlock(&st->buf_lock);
 	return ret;
 }

 /**
  * adxrs450_spi_write_reg_16() - write 2 bytes data to a register pair
  * @indio_dev: device associated with child of actual actual iio_dev
  * @reg_address: the address of the lower of the two registers,which should be
  *	an even address, the second register's address is reg_address + 1.
  * @val: value to be written.
  **/
 static int adxrs450_spi_write_reg_16(struct iio_dev *indio_dev,
 				     u8 reg_address,
 				     u16 val)
 {
 	struct adxrs450_state *st = iio_priv(indio_dev);
 	u32 tx;
 	int ret;

 	mutex_lock(&st->buf_lock);
 	tx = ADXRS450_WRITE_DATA | (reg_address << 17) | (val << 1);

 	if (!(hweight32(tx) & 1))
 		tx |= ADXRS450_P;

 	st->tx = cpu_to_be32(tx);
 	ret = spi_write(st->us, &st->tx, sizeof(st->tx));
 	if (ret)
 		dev_err(&st->us->dev, "problem while writing 16 bit register 0x%02x\n",
 			reg_address);
 	usleep_range(100, 1000); /* enforce sequential transfer delay 0.1ms */
 	mutex_unlock(&st->buf_lock);
 	return ret;
 }

 /**
  * adxrs450_spi_sensor_data() - read 2 bytes sensor data
  * @indio_dev: device associated with child of actual iio_dev
  * @val: somewhere to pass back the value read
  **/
 static int adxrs450_spi_sensor_data(struct iio_dev *indio_dev, s16 *val)
 {
 	struct spi_message msg;
 	struct adxrs450_state *st = iio_priv(indio_dev);
 	int ret;
 	struct spi_transfer xfers[] = {
 		{
 			.tx_buf = &st->tx,
 			.bits_per_word = 8,
 			.len = sizeof(st->tx),
 			.cs_change = 1,
 		}, {
 			.rx_buf = &st->rx,
 			.bits_per_word = 8,
 			.len = sizeof(st->rx),
 		},
 	};

 	mutex_lock(&st->buf_lock);
 	st->tx = cpu_to_be32(ADXRS450_SENSOR_DATA);

 	spi_message_init(&msg);
 	spi_message_add_tail(&xfers[0], &msg);
 	spi_message_add_tail(&xfers[1], &msg);
 	ret = spi_sync(st->us, &msg);
 	if (ret) {
 		dev_err(&st->us->dev, "Problem while reading sensor data\n");
 		goto error_ret;
 	}

 	*val = (be32_to_cpu(st->rx) >> 10) & 0xFFFF;

 error_ret:
 	mutex_unlock(&st->buf_lock);
 	return ret;
 }

 /**
  * adxrs450_spi_initial() - use for initializing procedure.
  * @st: device instance specific data
  * @val: somewhere to pass back the value read
  * @chk: Whether to perform fault check
  **/
 static int adxrs450_spi_initial(struct adxrs450_state *st,
 		u32 *val, char chk)
 {
 	int ret;
 	u32 tx;
 	struct spi_transfer xfers = {
 		.tx_buf = &st->tx,
 		.rx_buf = &st->rx,
 		.bits_per_word = 8,
 		.len = sizeof(st->tx),
 	};

 	mutex_lock(&st->buf_lock);
 	tx = ADXRS450_SENSOR_DATA;
 	if (chk)
 		tx |= (ADXRS450_CHK | ADXRS450_P);
 	st->tx = cpu_to_be32(tx);
 	ret = spi_sync_transfer(st->us, &xfers, 1);
 	if (ret) {
 		dev_err(&st->us->dev, "Problem while reading initializing data\n");
 		goto error_ret;
 	}

 	*val = be32_to_cpu(st->rx);

 error_ret:
 	mutex_unlock(&st->buf_lock);
 	return ret;
 }

 /* Recommended Startup Sequence by spec */
 static int adxrs450_initial_setup(struct iio_dev *indio_dev)
 {
 	u32 t;
 	u16 data;
 	int ret;
 	struct adxrs450_state *st = iio_priv(indio_dev);

 	msleep(ADXRS450_STARTUP_DELAY*2);
 	ret = adxrs450_spi_initial(st, &t, 1);
 	if (ret)
 		return ret;
 	if (t != 0x01)
 		dev_warn(&st->us->dev, "The initial power on response is not correct! Restart without reset?\n");

 	msleep(ADXRS450_STARTUP_DELAY);
 	ret = adxrs450_spi_initial(st, &t, 0);
 	if (ret)
 		return ret;

 	msleep(ADXRS450_STARTUP_DELAY);
 	ret = adxrs450_spi_initial(st, &t, 0);
 	if (ret)
 		return ret;
 	if (((t & 0xff) | 0x01) != 0xff || ADXRS450_GET_ST(t) != 2) {
 		dev_err(&st->us->dev, "The second response is not correct!\n");
 		return -EIO;

 	}
 	ret = adxrs450_spi_initial(st, &t, 0);
 	if (ret)
 		return ret;
 	if (((t & 0xff) | 0x01) != 0xff || ADXRS450_GET_ST(t) != 2) {
 		dev_err(&st->us->dev, "The third response is not correct!\n");
 		return -EIO;

 	}
 	ret = adxrs450_spi_read_reg_16(indio_dev, ADXRS450_FAULT1, &data);
 	if (ret)
 		return ret;
 	if (data & 0x0fff) {
 		dev_err(&st->us->dev, "The device is not in normal status!\n");
 		return -EINVAL;
 	}

 	return 0;
 }

 static int adxrs450_write_raw(struct iio_dev *indio_dev,
 			      struct iio_chan_spec const *chan,
 			      int val,
 			      int val2,
 			      long mask)
 {
 	int ret;
 	switch (mask) {
 	case IIO_CHAN_INFO_CALIBBIAS:
 		if (val < -0x400 || val >= 0x400)
 			return -EINVAL;
 		ret = adxrs450_spi_write_reg_16(indio_dev,
 						ADXRS450_DNC1, val);
 		break;
 	default:
 		ret = -EINVAL;
 		break;
 	}
 	return ret;
 }

 static int adxrs450_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int *val,
 			     int *val2,
 			     long mask)
 {
 	int ret;
 	s16 t;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		switch (chan->type) {
 		case IIO_ANGL_VEL:
 			ret = adxrs450_spi_sensor_data(indio_dev, &t);
 			if (ret)
 				break;
 			*val = t;
 			ret = IIO_VAL_INT;
 			break;
 		case IIO_TEMP:
 			ret = adxrs450_spi_read_reg_16(indio_dev,
 						       ADXRS450_TEMP1, &t);
 			if (ret)
 				break;
 			*val = (t >> 6) + 225;
 			ret = IIO_VAL_INT;
 			break;
 		default:
 			ret = -EINVAL;
 			break;
 		}
 		break;
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_ANGL_VEL:
 			*val = 0;
 			*val2 = 218166;
 			return IIO_VAL_INT_PLUS_NANO;
 		case IIO_TEMP:
 			*val = 200;
 			*val2 = 0;
 			return IIO_VAL_INT;
 		default:
 			return -EINVAL;
 		}
 		break;
 	case IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW:
 		ret = adxrs450_spi_read_reg_16(indio_dev, ADXRS450_QUAD1, &t);
 		if (ret)
 			break;
 		*val = t;
 		ret = IIO_VAL_INT;
 		break;
 	case IIO_CHAN_INFO_CALIBBIAS:
 		ret = adxrs450_spi_read_reg_16(indio_dev, ADXRS450_DNC1, &t);
 		if (ret)
 			break;
 		*val = sign_extend32(t, 9);
 		ret = IIO_VAL_INT;
 		break;
 	default:
 		ret = -EINVAL;
 		break;
 	}

 	return ret;
 }

 static const struct iio_chan_spec adxrs450_channels[2][2] = {
 	[ID_ADXRS450] = {
 		{
 			.type = IIO_ANGL_VEL,
 			.modified = 1,
 			.channel2 = IIO_MOD_Z,
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_CALIBBIAS) |
 			BIT(IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW) |
 			BIT(IIO_CHAN_INFO_SCALE),
 		}, {
 			.type = IIO_TEMP,
 			.indexed = 1,
 			.channel = 0,
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_SCALE),
 		}
 	},
 	[ID_ADXRS453] = {
 		{
 			.type = IIO_ANGL_VEL,
 			.modified = 1,
 			.channel2 = IIO_MOD_Z,
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_SCALE) |
 			BIT(IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW),
 		}, {
 			.type = IIO_TEMP,
 			.indexed = 1,
 			.channel = 0,
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_SCALE),
 		}
 	},
 };

 static const struct iio_info adxrs450_info = {
 	.driver_module = THIS_MODULE,
 	.read_raw = &adxrs450_read_raw,
 	.write_raw = &adxrs450_write_raw,
 };

 static int adxrs450_probe(struct spi_device *spi)
 {
 	int ret;
 	struct adxrs450_state *st;
 	struct iio_dev *indio_dev;

 	/* setup the industrialio driver allocated elements */
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 	if (!indio_dev)
 		return -ENOMEM;
 	st = iio_priv(indio_dev);
 	st->us = spi;
 	mutex_init(&st->buf_lock);
 	/* This is only used for removal purposes */
 	spi_set_drvdata(spi, indio_dev);

 	indio_dev->dev.parent = &spi->dev;
 	indio_dev->info = &adxrs450_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels =
 		adxrs450_channels[spi_get_device_id(spi)->driver_data];
 	indio_dev->num_channels = ARRAY_SIZE(adxrs450_channels);
 	indio_dev->name = spi->dev.driver->name;

 	ret = iio_device_register(indio_dev);
 	if (ret)
 		return ret;

 	/* Get the device into a sane initial state */
 	ret = adxrs450_initial_setup(indio_dev);
 	if (ret)
 		goto error_initial;
 	return 0;
 error_initial:
 	iio_device_unregister(indio_dev);
 	return ret;
 }

 static int adxrs450_remove(struct spi_device *spi)
 {
 	iio_device_unregister(spi_get_drvdata(spi));

 	return 0;
 }

 static const struct spi_device_id adxrs450_id[] = {
 	{"adxrs450", ID_ADXRS450},
 	{"adxrs453", ID_ADXRS453},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, adxrs450_id);

 static struct spi_driver adxrs450_driver = {
 	.driver = {
 		.name = "adxrs450",
 		.owner = THIS_MODULE,
 	},
 	.probe = adxrs450_probe,
 	.remove = adxrs450_remove,
 	.id_table	= adxrs450_id,
 };
 module_spi_driver(adxrs450_driver);

 MODULE_AUTHOR("Cliff Cai <cliff.cai@xxxxxxxxxx>");
 MODULE_DESCRIPTION("Analog Devices ADXRS450/ADXRS453 Gyroscope SPI driver");
 MODULE_LICENSE("GPL v2");
	/*
	* ADXRS450/ADXRS453 Digital Output Gyroscope Driver
	*
	* Copyright 2011 Analog Devices Inc.
	*
	* Licensed under the GPL-2.
	*/

	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/delay.h>
	#include <linux/mutex.h>
	#include <linux/device.h>
	#include <linux/kernel.h>
	#include <linux/spi/spi.h>
	#include <linux/slab.h>
	#include <linux/sysfs.h>
	#include <linux/list.h>
	#include <linux/module.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>

	#define ADXRS450_STARTUP_DELAY 50 /* ms */

	/* The MSB for the spi commands */
	#define ADXRS450_SENSOR_DATA (0x20 << 24)
	#define ADXRS450_WRITE_DATA (0x40 << 24)
	#define ADXRS450_READ_DATA (0x80 << 24)

	#define ADXRS450_RATE1 0x00 /* Rate Registers */
	#define ADXRS450_TEMP1 0x02 /* Temperature Registers */
	#define ADXRS450_LOCST1 0x04 /* Low CST Memory Registers */
	#define ADXRS450_HICST1 0x06 /* High CST Memory Registers */
	#define ADXRS450_QUAD1 0x08 /* Quad Memory Registers */
	#define ADXRS450_FAULT1 0x0A /* Fault Registers */
	#define ADXRS450_PID1 0x0C /* Part ID Register 1 */
	#define ADXRS450_SNH 0x0E /* Serial Number Registers, 4 bytes */
	#define ADXRS450_SNL 0x10
	#define ADXRS450_DNC1 0x12 /* Dynamic Null Correction Registers */
	/* Check bits */
	#define ADXRS450_P 0x01
	#define ADXRS450_CHK 0x02
	#define ADXRS450_CST 0x04
	#define ADXRS450_PWR 0x08
	#define ADXRS450_POR 0x10
	#define ADXRS450_NVM 0x20
	#define ADXRS450_Q 0x40
	#define ADXRS450_PLL 0x80
	#define ADXRS450_UV 0x100
	#define ADXRS450_OV 0x200
	#define ADXRS450_AMP 0x400
	#define ADXRS450_FAIL 0x800

	#define ADXRS450_WRERR_MASK (0x7 << 29)

	#define ADXRS450_MAX_RX 4
	#define ADXRS450_MAX_TX 4

	#define ADXRS450_GET_ST(a) ((a >> 26) & 0x3)

	enum {
	ID_ADXRS450,
	ID_ADXRS453,
	};

	/**
	* struct adxrs450_state - device instance specific data
	* @us: actual spi_device
	* @buf_lock: mutex to protect tx and rx
	* @tx: transmit buffer
	* @rx: receive buffer
	**/
	struct adxrs450_state {
	struct spi_device *us;
	struct mutex buf_lock;
	__be32 tx ____cacheline_aligned;
	__be32 rx;

	};

	/**
	* adxrs450_spi_read_reg_16() - read 2 bytes from a register pair
	* @indio_dev: device associated with child of actual iio_dev
	* @reg_address: the address of the lower of the two registers, which should be
	* an even address, the second register's address is reg_address + 1.
	* @val: somewhere to pass back the value read
	**/
	static int adxrs450_spi_read_reg_16(struct iio_dev *indio_dev,
	u8 reg_address,
	u16 *val)
	{
	struct spi_message msg;
	struct adxrs450_state *st = iio_priv(indio_dev);
	u32 tx;
	int ret;
	struct spi_transfer xfers[] = {
	{
	.tx_buf = &st->tx,
	.bits_per_word = 8,
	.len = sizeof(st->tx),
	.cs_change = 1,
	}, {
	.rx_buf = &st->rx,
	.bits_per_word = 8,
	.len = sizeof(st->rx),
	},
	};

	mutex_lock(&st->buf_lock);
	tx = ADXRS450_READ_DATA \| (reg_address << 17);

	if (!(hweight32(tx) & 1))
	tx \|= ADXRS450_P;

	st->tx = cpu_to_be32(tx);
	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	spi_message_add_tail(&xfers[1], &msg);
	ret = spi_sync(st->us, &msg);
	if (ret) {
	dev_err(&st->us->dev, "problem while reading 16 bit register 0x%02x\n",
	reg_address);
	goto error_ret;
	}

	*val = (be32_to_cpu(st->rx) >> 5) & 0xFFFF;

	error_ret:
	mutex_unlock(&st->buf_lock);
	return ret;
	}

	/**
	* adxrs450_spi_write_reg_16() - write 2 bytes data to a register pair
	* @indio_dev: device associated with child of actual actual iio_dev
	* @reg_address: the address of the lower of the two registers,which should be
	* an even address, the second register's address is reg_address + 1.
	* @val: value to be written.
	**/
	static int adxrs450_spi_write_reg_16(struct iio_dev *indio_dev,
	u8 reg_address,
	u16 val)
	{
	struct adxrs450_state *st = iio_priv(indio_dev);
	u32 tx;
	int ret;

	mutex_lock(&st->buf_lock);
	tx = ADXRS450_WRITE_DATA \| (reg_address << 17) \| (val << 1);

	if (!(hweight32(tx) & 1))
	tx \|= ADXRS450_P;

	st->tx = cpu_to_be32(tx);
	ret = spi_write(st->us, &st->tx, sizeof(st->tx));
	if (ret)
	dev_err(&st->us->dev, "problem while writing 16 bit register 0x%02x\n",
	reg_address);
	usleep_range(100, 1000); /* enforce sequential transfer delay 0.1ms */
	mutex_unlock(&st->buf_lock);
	return ret;
	}

	/**
	* adxrs450_spi_sensor_data() - read 2 bytes sensor data
	* @indio_dev: device associated with child of actual iio_dev
	* @val: somewhere to pass back the value read
	**/
	static int adxrs450_spi_sensor_data(struct iio_dev indio_dev, s16 val)
	{
	struct spi_message msg;
	struct adxrs450_state *st = iio_priv(indio_dev);
	int ret;
	struct spi_transfer xfers[] = {
	{
	.tx_buf = &st->tx,
	.bits_per_word = 8,
	.len = sizeof(st->tx),
	.cs_change = 1,
	}, {
	.rx_buf = &st->rx,
	.bits_per_word = 8,
	.len = sizeof(st->rx),
	},
	};

	mutex_lock(&st->buf_lock);
	st->tx = cpu_to_be32(ADXRS450_SENSOR_DATA);

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	spi_message_add_tail(&xfers[1], &msg);
	ret = spi_sync(st->us, &msg);
	if (ret) {
	dev_err(&st->us->dev, "Problem while reading sensor data\n");
	goto error_ret;
	}

	*val = (be32_to_cpu(st->rx) >> 10) & 0xFFFF;

	error_ret:
	mutex_unlock(&st->buf_lock);
	return ret;
	}

	/**
	* adxrs450_spi_initial() - use for initializing procedure.
	* @st: device instance specific data
	* @val: somewhere to pass back the value read
	* @chk: Whether to perform fault check
	**/
	static int adxrs450_spi_initial(struct adxrs450_state *st,
	u32 *val, char chk)
	{
	int ret;
	u32 tx;
	struct spi_transfer xfers = {
	.tx_buf = &st->tx,
	.rx_buf = &st->rx,
	.bits_per_word = 8,
	.len = sizeof(st->tx),
	};

	mutex_lock(&st->buf_lock);
	tx = ADXRS450_SENSOR_DATA;
	if (chk)
	tx \|= (ADXRS450_CHK \| ADXRS450_P);
	st->tx = cpu_to_be32(tx);
	ret = spi_sync_transfer(st->us, &xfers, 1);
	if (ret) {
	dev_err(&st->us->dev, "Problem while reading initializing data\n");
	goto error_ret;
	}

	*val = be32_to_cpu(st->rx);

	error_ret:
	mutex_unlock(&st->buf_lock);
	return ret;
	}

	/* Recommended Startup Sequence by spec */
	static int adxrs450_initial_setup(struct iio_dev *indio_dev)
	{
	u32 t;
	u16 data;
	int ret;
	struct adxrs450_state *st = iio_priv(indio_dev);

	msleep(ADXRS450_STARTUP_DELAY*2);
	ret = adxrs450_spi_initial(st, &t, 1);
	if (ret)
	return ret;
	if (t != 0x01)
	dev_warn(&st->us->dev, "The initial power on response is not correct! Restart without reset?\n");

	msleep(ADXRS450_STARTUP_DELAY);
	ret = adxrs450_spi_initial(st, &t, 0);
	if (ret)
	return ret;

	msleep(ADXRS450_STARTUP_DELAY);
	ret = adxrs450_spi_initial(st, &t, 0);
	if (ret)
	return ret;
	if (((t & 0xff) \| 0x01) != 0xff \|\| ADXRS450_GET_ST(t) != 2) {
	dev_err(&st->us->dev, "The second response is not correct!\n");
	return -EIO;

	}
	ret = adxrs450_spi_initial(st, &t, 0);
	if (ret)
	return ret;
	if (((t & 0xff) \| 0x01) != 0xff \|\| ADXRS450_GET_ST(t) != 2) {
	dev_err(&st->us->dev, "The third response is not correct!\n");
	return -EIO;

	}
	ret = adxrs450_spi_read_reg_16(indio_dev, ADXRS450_FAULT1, &data);
	if (ret)
	return ret;
	if (data & 0x0fff) {
	dev_err(&st->us->dev, "The device is not in normal status!\n");
	return -EINVAL;
	}

	return 0;
	}

	static int adxrs450_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val,
	int val2,
	long mask)
	{
	int ret;
	switch (mask) {
	case IIO_CHAN_INFO_CALIBBIAS:
	if (val < -0x400 \|\| val >= 0x400)
	return -EINVAL;
	ret = adxrs450_spi_write_reg_16(indio_dev,
	ADXRS450_DNC1, val);
	break;
	default:
	ret = -EINVAL;
	break;
	}
	return ret;
	}

	static int adxrs450_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int *val,
	int *val2,
	long mask)
	{
	int ret;
	s16 t;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	switch (chan->type) {
	case IIO_ANGL_VEL:
	ret = adxrs450_spi_sensor_data(indio_dev, &t);
	if (ret)
	break;
	*val = t;
	ret = IIO_VAL_INT;
	break;
	case IIO_TEMP:
	ret = adxrs450_spi_read_reg_16(indio_dev,
	ADXRS450_TEMP1, &t);
	if (ret)
	break;
	*val = (t >> 6) + 225;
	ret = IIO_VAL_INT;
	break;
	default:
	ret = -EINVAL;
	break;
	}
	break;
	case IIO_CHAN_INFO_SCALE:
	switch (chan->type) {
	case IIO_ANGL_VEL:
	*val = 0;
	*val2 = 218166;
	return IIO_VAL_INT_PLUS_NANO;
	case IIO_TEMP:
	*val = 200;
	*val2 = 0;
	return IIO_VAL_INT;
	default:
	return -EINVAL;
	}
	break;
	case IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW:
	ret = adxrs450_spi_read_reg_16(indio_dev, ADXRS450_QUAD1, &t);
	if (ret)
	break;
	*val = t;
	ret = IIO_VAL_INT;
	break;
	case IIO_CHAN_INFO_CALIBBIAS:
	ret = adxrs450_spi_read_reg_16(indio_dev, ADXRS450_DNC1, &t);
	if (ret)
	break;
	*val = sign_extend32(t, 9);
	ret = IIO_VAL_INT;
	break;
	default:
	ret = -EINVAL;
	break;
	}

	return ret;
	}

	static const struct iio_chan_spec adxrs450_channels[2][2] = {
	[ID_ADXRS450] = {
	{
	.type = IIO_ANGL_VEL,
	.modified = 1,
	.channel2 = IIO_MOD_Z,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_CALIBBIAS) \|
	BIT(IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	}, {
	.type = IIO_TEMP,
	.indexed = 1,
	.channel = 0,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	}
	},
	[ID_ADXRS453] = {
	{
	.type = IIO_ANGL_VEL,
	.modified = 1,
	.channel2 = IIO_MOD_Z,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE) \|
	BIT(IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW),
	}, {
	.type = IIO_TEMP,
	.indexed = 1,
	.channel = 0,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	}
	},
	};

	static const struct iio_info adxrs450_info = {
	.driver_module = THIS_MODULE,
	.read_raw = &adxrs450_read_raw,
	.write_raw = &adxrs450_write_raw,
	};

	static int adxrs450_probe(struct spi_device *spi)
	{
	int ret;
	struct adxrs450_state *st;
	struct iio_dev *indio_dev;

	/* setup the industrialio driver allocated elements */
	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
	if (!indio_dev)
	return -ENOMEM;
	st = iio_priv(indio_dev);
	st->us = spi;
	mutex_init(&st->buf_lock);
	/* This is only used for removal purposes */
	spi_set_drvdata(spi, indio_dev);

	indio_dev->dev.parent = &spi->dev;
	indio_dev->info = &adxrs450_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels =
	adxrs450_channels[spi_get_device_id(spi)->driver_data];
	indio_dev->num_channels = ARRAY_SIZE(adxrs450_channels);
	indio_dev->name = spi->dev.driver->name;

	ret = iio_device_register(indio_dev);
	if (ret)
	return ret;

	/* Get the device into a sane initial state */
	ret = adxrs450_initial_setup(indio_dev);
	if (ret)
	goto error_initial;
	return 0;
	error_initial:
	iio_device_unregister(indio_dev);
	return ret;
	}

	static int adxrs450_remove(struct spi_device *spi)
	{
	iio_device_unregister(spi_get_drvdata(spi));

	return 0;
	}

	static const struct spi_device_id adxrs450_id[] = {
	{"adxrs450", ID_ADXRS450},
	{"adxrs453", ID_ADXRS453},
	{}
	};
	MODULE_DEVICE_TABLE(spi, adxrs450_id);

	static struct spi_driver adxrs450_driver = {
	.driver = {
	.name = "adxrs450",
	.owner = THIS_MODULE,
	},
	.probe = adxrs450_probe,
	.remove = adxrs450_remove,
	.id_table = adxrs450_id,
	};
	module_spi_driver(adxrs450_driver);

	MODULE_AUTHOR("Cliff Cai <cliff.cai@xxxxxxxxxx>");
	MODULE_DESCRIPTION("Analog Devices ADXRS450/ADXRS453 Gyroscope SPI driver");
	MODULE_LICENSE("GPL v2");