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* ADXRS450 Digital Output Gyroscope Driver
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* Copyright 2011 Analog Devices Inc.
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* Licensed under the GPL-2.
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/gpio.h>
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#include <linux/delay.h>
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#include <linux/mutex.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/spi/spi.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/list.h>
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#include "../adc/adc.h"
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* adxrs450_spi_read_reg_16() - read 2 bytes from a register pair
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* @dev: device associated with child of actual iio_dev
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* @reg_address: the address of the lower of the two registers,which should be an even address,
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* Second register's address is reg_address + 1.
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* @val: somewhere to pass back the value read
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static int adxrs450_spi_read_reg_16(struct device *dev,
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struct spi_message msg;
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct adxrs450_state *st = iio_dev_get_devdata(indio_dev);
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struct spi_transfer xfers[] = {
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mutex_lock(&st->buf_lock);
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st->tx[0] = ADXRS450_READ_DATA | (reg_address >> 7);
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st->tx[1] = reg_address << 1;
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if (!(hweight32(be32_to_cpu(*(u32 *)st->tx)) & 1))
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st->tx[3] |= ADXRS450_P;
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spi_message_init(&msg);
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spi_message_add_tail(&xfers[0], &msg);
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spi_message_add_tail(&xfers[1], &msg);
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ret = spi_sync(st->us, &msg);
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dev_err(&st->us->dev, "problem while reading 16 bit register 0x%02x\n",
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*val = (be32_to_cpu(*(u32 *)st->rx) >> 5) & 0xFFFF;
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mutex_unlock(&st->buf_lock);
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* adxrs450_spi_write_reg_16() - write 2 bytes data to a register pair
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* @dev: device associated with child of actual actual iio_dev
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* @reg_address: the address of the lower of the two registers,which should be an even address,
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* Second register's address is reg_address + 1.
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* @val: value to be written.
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static int adxrs450_spi_write_reg_16(struct device *dev,
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struct spi_message msg;
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct adxrs450_state *st = iio_dev_get_devdata(indio_dev);
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struct spi_transfer xfers = {
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mutex_lock(&st->buf_lock);
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st->tx[0] = ADXRS450_WRITE_DATA | reg_address >> 7;
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st->tx[1] = reg_address << 1 | val >> 15;
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st->tx[2] = val >> 7;
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st->tx[3] = val << 1;
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if (!(hweight32(be32_to_cpu(*(u32 *)st->tx)) & 1))
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st->tx[3] |= ADXRS450_P;
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spi_message_init(&msg);
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spi_message_add_tail(&xfers, &msg);
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ret = spi_sync(st->us, &msg);
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dev_err(&st->us->dev, "problem while writing 16 bit register 0x%02x\n",
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msleep(1); /* enforce sequential transfer delay 0.1ms */
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mutex_unlock(&st->buf_lock);
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* adxrs450_spi_sensor_data() - read 2 bytes sensor data
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* @dev: device associated with child of actual iio_dev
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* @val: somewhere to pass back the value read
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static int adxrs450_spi_sensor_data(struct device *dev, s16 *val)
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struct spi_message msg;
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct adxrs450_state *st = iio_dev_get_devdata(indio_dev);
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struct spi_transfer xfers[] = {
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mutex_lock(&st->buf_lock);
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st->tx[0] = ADXRS450_SENSOR_DATA;
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spi_message_init(&msg);
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spi_message_add_tail(&xfers[0], &msg);
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spi_message_add_tail(&xfers[1], &msg);
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ret = spi_sync(st->us, &msg);
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dev_err(&st->us->dev, "Problem while reading sensor data\n");
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*val = (be32_to_cpu(*(u32 *)st->rx) >> 10) & 0xFFFF;
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mutex_unlock(&st->buf_lock);
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* adxrs450_spi_initial() - use for initializing procedure.
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* @st: device instance specific data
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* @val: somewhere to pass back the value read
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static int adxrs450_spi_initial(struct adxrs450_state *st,
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struct spi_message msg;
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struct spi_transfer xfers = {
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mutex_lock(&st->buf_lock);
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st->tx[0] = ADXRS450_SENSOR_DATA;
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st->tx[3] |= (ADXRS450_CHK | ADXRS450_P);
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spi_message_init(&msg);
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spi_message_add_tail(&xfers, &msg);
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ret = spi_sync(st->us, &msg);
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dev_err(&st->us->dev, "Problem while reading initializing data\n");
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*val = be32_to_cpu(*(u32 *)st->rx);
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mutex_unlock(&st->buf_lock);
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static ssize_t adxrs450_read_temp(struct device *dev,
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struct device_attribute *attr,
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ret = adxrs450_spi_read_reg_16(dev,
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return sprintf(buf, "%d\n", t >> 7);
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static ssize_t adxrs450_read_quad(struct device *dev,
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struct device_attribute *attr,
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ret = adxrs450_spi_read_reg_16(dev,
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return sprintf(buf, "%d\n", t);
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static ssize_t adxrs450_write_dnc(struct device *dev,
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struct device_attribute *attr,
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ret = strict_strtol(buf, 10, &val);
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ret = adxrs450_spi_write_reg_16(dev,
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return ret ? ret : len;
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static ssize_t adxrs450_read_sensor_data(struct device *dev,
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struct device_attribute *attr,
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ret = adxrs450_spi_sensor_data(dev, &t);
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return sprintf(buf, "%d\n", t);
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/* Recommended Startup Sequence by spec */
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static int adxrs450_initial_setup(struct adxrs450_state *st)
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struct device *dev = &st->indio_dev->dev;
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msleep(ADXRS450_STARTUP_DELAY*2);
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ret = adxrs450_spi_initial(st, &t, 1);
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dev_warn(&st->us->dev, "The initial power on response "
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"is not correct! Restart without reset?\n");
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msleep(ADXRS450_STARTUP_DELAY);
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ret = adxrs450_spi_initial(st, &t, 0);
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msleep(ADXRS450_STARTUP_DELAY);
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ret = adxrs450_spi_initial(st, &t, 0);
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if (((t & 0xff) | 0x01) != 0xff || ADXRS450_GET_ST(t) != 2) {
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dev_err(&st->us->dev, "The second response is not correct!\n");
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ret = adxrs450_spi_initial(st, &t, 0);
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if (((t & 0xff) | 0x01) != 0xff || ADXRS450_GET_ST(t) != 2) {
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dev_err(&st->us->dev, "The third response is not correct!\n");
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ret = adxrs450_spi_read_reg_16(dev, ADXRS450_FAULT1, &data);
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dev_err(&st->us->dev, "The device is not in normal status!\n");
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ret = adxrs450_spi_read_reg_16(dev, ADXRS450_PID1, &data);
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dev_info(&st->us->dev, "The Part ID is 0x%x\n", data);
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ret = adxrs450_spi_read_reg_16(dev, ADXRS450_SNL, &data);
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ret = adxrs450_spi_read_reg_16(dev, ADXRS450_SNH, &data);
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dev_info(&st->us->dev, "The Serial Number is 0x%x\n", t);
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static IIO_DEV_ATTR_GYRO_Z(adxrs450_read_sensor_data, 0);
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static IIO_DEV_ATTR_TEMP_RAW(adxrs450_read_temp);
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static IIO_DEV_ATTR_GYRO_Z_QUADRATURE_CORRECTION(adxrs450_read_quad, 0);
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static IIO_DEV_ATTR_GYRO_Z_CALIBBIAS(S_IWUSR,
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NULL, adxrs450_write_dnc, 0);
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static IIO_CONST_ATTR(name, "adxrs450");
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static struct attribute *adxrs450_attributes[] = {
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&iio_dev_attr_gyro_z_raw.dev_attr.attr,
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&iio_dev_attr_temp_raw.dev_attr.attr,
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&iio_dev_attr_gyro_z_quadrature_correction_raw.dev_attr.attr,
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&iio_dev_attr_gyro_z_calibbias.dev_attr.attr,
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&iio_const_attr_name.dev_attr.attr,
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static const struct attribute_group adxrs450_attribute_group = {
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.attrs = adxrs450_attributes,
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static const struct iio_info adxrs450_info = {
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.attrs = &adxrs450_attribute_group,
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.driver_module = THIS_MODULE,
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static int __devinit adxrs450_probe(struct spi_device *spi)
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int ret, regdone = 0;
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struct adxrs450_state *st = kzalloc(sizeof *st, GFP_KERNEL);
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/* This is only used for removal purposes */
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spi_set_drvdata(spi, st);
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/* Allocate the comms buffers */
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st->rx = kzalloc(sizeof(*st->rx)*ADXRS450_MAX_RX, GFP_KERNEL);
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if (st->rx == NULL) {
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st->tx = kzalloc(sizeof(*st->tx)*ADXRS450_MAX_TX, GFP_KERNEL);
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if (st->tx == NULL) {
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mutex_init(&st->buf_lock);
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/* setup the industrialio driver allocated elements */
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st->indio_dev = iio_allocate_device(0);
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if (st->indio_dev == NULL) {
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st->indio_dev->dev.parent = &spi->dev;
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st->indio_dev->info = &adxrs450_info;
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st->indio_dev->dev_data = (void *)(st);
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st->indio_dev->modes = INDIO_DIRECT_MODE;
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ret = iio_device_register(st->indio_dev);
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/* Get the device into a sane initial state */
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ret = adxrs450_initial_setup(st);
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iio_device_unregister(st->indio_dev);
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iio_free_device(st->indio_dev);
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static int adxrs450_remove(struct spi_device *spi)
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struct adxrs450_state *st = spi_get_drvdata(spi);
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iio_device_unregister(st->indio_dev);
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static struct spi_driver adxrs450_driver = {
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.owner = THIS_MODULE,
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.probe = adxrs450_probe,
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.remove = __devexit_p(adxrs450_remove),
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static __init int adxrs450_init(void)
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return spi_register_driver(&adxrs450_driver);
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module_init(adxrs450_init);
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static __exit void adxrs450_exit(void)
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spi_unregister_driver(&adxrs450_driver);
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module_exit(adxrs450_exit);
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MODULE_AUTHOR("Cliff Cai <cliff.cai@xxxxxxxxxx>");
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MODULE_DESCRIPTION("Analog Devices ADXRS450 Gyroscope SPI driver");
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MODULE_LICENSE("GPL v2");