text: /*
   * sca3000_core.c -- support VTI sca3000 series accelerometers via SPI
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published by
   * the Free Software Foundation.
   *
   * Copyright (c) 2009 Jonathan Cameron <jic23@cam.ac.uk>
   *
   * See industrialio/accels/sca3000.h for comments.
   */
  
  #include <linux/interrupt.h>
  #include <linux/gpio.h>
  #include <linux/fs.h>
  #include <linux/device.h>
  #include <linux/slab.h>
  #include <linux/kernel.h>
  #include <linux/spi/spi.h>
  #include <linux/sysfs.h>
  #include "../iio.h"
  #include "../sysfs.h"
  #include "../ring_generic.h"
  
  #include "accel.h"
  #include "sca3000.h"
  
  enum sca3000_variant {
  	d01,
  	e02,
  	e04,
  	e05,
  };
  
  /* Note where option modes are not defined, the chip simply does not
   * support any.
   * Other chips in the sca3000 series use i2c and are not included here.
   *
   * Some of these devices are only listed in the family data sheet and
   * do not actually appear to be available.
   */
  static const struct sca3000_chip_info sca3000_spi_chip_info_tbl[] = {
  	{
  		.name = "sca3000-d01",
  		.scale = " 0.0073575",
  		.temp_output = true,
  		.measurement_mode_freq = 250,
  		.option_mode_1 = SCA3000_OP_MODE_BYPASS,
  		.option_mode_1_freq = 250,
  	}, {
  		.name = "sca3000-e02",
  		.scale = "0.00981",
  		.measurement_mode_freq = 125,
  		.option_mode_1 = SCA3000_OP_MODE_NARROW,
  		.option_mode_1_freq = 63,
  	}, {
  		.name = "sca3000-e04",
  		.scale = "0.01962",
  		.measurement_mode_freq = 100,
  		.option_mode_1 = SCA3000_OP_MODE_NARROW,
  		.option_mode_1_freq = 50,
  		.option_mode_2 = SCA3000_OP_MODE_WIDE,
  		.option_mode_2_freq = 400,
  	}, {
  		.name = "sca3000-e05",
  		.scale = "0.0613125",
  		.measurement_mode_freq = 200,
  		.option_mode_1 = SCA3000_OP_MODE_NARROW,
  		.option_mode_1_freq = 50,
  		.option_mode_2 = SCA3000_OP_MODE_WIDE,
  		.option_mode_2_freq = 400,
  	},
  };
  
  
  int sca3000_write_reg(struct sca3000_state *st, u8 address, u8 val)
  {
  	struct spi_transfer xfer = {
  		.bits_per_word = 8,
  		.len = 2,
  		.cs_change = 1,
  		.tx_buf = st->tx,
  	};
  	struct spi_message msg;
  
  	st->tx[0] = SCA3000_WRITE_REG(address);
  	st->tx[1] = val;
  	spi_message_init(&msg);
  	spi_message_add_tail(&xfer, &msg);
  
  	return spi_sync(st->us, &msg);
  }
  
  int sca3000_read_data(struct sca3000_state *st,
  		      uint8_t reg_address_high,
  		      u8 **rx_p,
  		      int len)
  {
  	int ret;
  	struct spi_message msg;
  	struct spi_transfer xfer = {
  		.bits_per_word = 8,
  		.len = len + 1,
  		.cs_change = 1,
  		.tx_buf = st->tx,
  	};
  
  	*rx_p = kmalloc(len + 1, GFP_KERNEL);
  	if (*rx_p == NULL) {
  		ret = -ENOMEM;
  		goto error_ret;
  	}
  	xfer.rx_buf = *rx_p;
  	st->tx[0] = SCA3000_READ_REG(reg_address_high);
  	spi_message_init(&msg);
  	spi_message_add_tail(&xfer, &msg);
  
  	ret = spi_sync(st->us, &msg);
  
  	if (ret) {
  		dev_err(get_device(&st->us->dev), "problem reading register");
  		goto error_free_rx;
  	}
  
  	return 0;
  error_free_rx:
  	kfree(*rx_p);
  error_ret:
  	return ret;
  
  }
  /**
   * sca3000_reg_lock_on() test if the ctrl register lock is on
   *
   * Lock must be held.
   **/
  static int sca3000_reg_lock_on(struct sca3000_state *st)
  {
  	u8 *rx;
  	int ret;
  
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_STATUS, &rx, 1);
  
  	if (ret < 0)
  		return ret;
  	ret = !(rx[1] & SCA3000_LOCKED);
  	kfree(rx);
  
  	return ret;
  }
  
  /**
   * __sca3000_unlock_reg_lock() unlock the control registers
   *
   * Note the device does not appear to support doing this in a single transfer.
   * This should only ever be used as part of ctrl reg read.
   * Lock must be held before calling this
   **/
  static int __sca3000_unlock_reg_lock(struct sca3000_state *st)
  {
  	struct spi_message msg;
  	struct spi_transfer xfer[3] = {
  		{
  			.bits_per_word = 8,
  			.len = 2,
  			.cs_change = 1,
  			.tx_buf = st->tx,
  		}, {
  			.bits_per_word = 8,
  			.len = 2,
  			.cs_change = 1,
  			.tx_buf = st->tx + 2,
  		}, {
  			.bits_per_word = 8,
  			.len = 2,
  			.cs_change = 1,
  			.tx_buf = st->tx + 4,
  		},
  	};
  	st->tx[0] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
  	st->tx[1] = 0x00;
  	st->tx[2] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
  	st->tx[3] = 0x50;
  	st->tx[4] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
  	st->tx[5] = 0xA0;
  	spi_message_init(&msg);
  	spi_message_add_tail(&xfer[0], &msg);
  	spi_message_add_tail(&xfer[1], &msg);
  	spi_message_add_tail(&xfer[2], &msg);
  
  	return spi_sync(st->us, &msg);
  }
  
  /**
   * sca3000_write_ctrl_reg() write to a lock protect ctrl register
   * @sel: selects which registers we wish to write to
   * @val: the value to be written
   *
   * Certain control registers are protected against overwriting by the lock
   * register and use a shared write address. This function allows writing of
   * these registers.
   * Lock must be held.
   **/
  static int sca3000_write_ctrl_reg(struct sca3000_state *st,
  				  uint8_t sel,
  				  uint8_t val)
  {
  
  	int ret;
  
  	ret = sca3000_reg_lock_on(st);
  	if (ret < 0)
  		goto error_ret;
  	if (ret) {
  		ret = __sca3000_unlock_reg_lock(st);
  		if (ret)
  			goto error_ret;
  	}
  
  	/* Set the control select register */
  	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_SEL, sel);
  	if (ret)
  		goto error_ret;
  
  	/* Write the actual value into the register */
  	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_DATA, val);
  
  error_ret:
  	return ret;
  }
  
  /* Crucial that lock is called before calling this */
  /**
   * sca3000_read_ctrl_reg() read from lock protected control register.
   *
   * Lock must be held.
   **/
  static int sca3000_read_ctrl_reg(struct sca3000_state *st,
  				 u8 ctrl_reg,
  				 u8 **rx_p)
  {
  	int ret;
  
  	ret = sca3000_reg_lock_on(st);
  	if (ret < 0)
  		goto error_ret;
  	if (ret) {
  		ret = __sca3000_unlock_reg_lock(st);
  		if (ret)
  			goto error_ret;
  	}
  	/* Set the control select register */
  	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_SEL, ctrl_reg);
  	if (ret)
  		goto error_ret;
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_CTRL_DATA, rx_p, 1);
  
  error_ret:
  	return ret;
  }
  
  #ifdef SCA3000_DEBUG
  /**
   * sca3000_check_status() check the status register
   *
   * Only used for debugging purposes
   **/
  static int sca3000_check_status(struct device *dev)
  {
  	u8 *rx;
  	int ret;
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_STATUS, &rx, 1);
  	if (ret < 0)
  		goto error_ret;
  	if (rx[1] & SCA3000_EEPROM_CS_ERROR)
  		dev_err(dev, "eeprom error\n");
  	if (rx[1] & SCA3000_SPI_FRAME_ERROR)
  		dev_err(dev, "Previous SPI Frame was corrupt\n");
  	kfree(rx);
  
  error_ret:
  	mutex_unlock(&st->lock);
  	return ret;
  }
  #endif /* SCA3000_DEBUG */
  
  /**
   * sca3000_read_13bit_signed() sysfs interface to read 13 bit signed registers
   *
   * These are described as signed 12 bit on the data sheet, which appears
   * to be a conventional 2's complement 13 bit.
   **/
  static ssize_t sca3000_read_13bit_signed(struct device *dev,
  					 struct device_attribute *attr,
  					 char *buf)
  {
  	int len = 0, ret;
  	int val;
  	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
  	u8 *rx;
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, this_attr->address, &rx, 2);
  	if (ret < 0)
  		goto error_ret;
  	val = sca3000_13bit_convert(rx[1], rx[2]);
  	len += sprintf(buf + len, "%d\n", val);
  	kfree(rx);
  error_ret:
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  
  static ssize_t sca3000_show_scale(struct device *dev,
  				  struct device_attribute *attr,
  				  char *buf)
  {
  	struct iio_dev *dev_info = dev_get_drvdata(dev);
  	struct sca3000_state *st = dev_info->dev_data;
  	return sprintf(buf, "%s\n", st->info->scale);
  }
  
  static ssize_t sca3000_show_name(struct device *dev,
  				 struct device_attribute *attr,
  				 char *buf)
  {
  	struct iio_dev *dev_info = dev_get_drvdata(dev);
  	struct sca3000_state *st = dev_info->dev_data;
  	return sprintf(buf, "%s\n", st->info->name);
  }
  /**
   * sca3000_show_reg() - sysfs interface to read the chip revision number
   **/
  static ssize_t sca3000_show_rev(struct device *dev,
  				struct device_attribute *attr,
  				char *buf)
  {
  	int len = 0, ret;
  	struct iio_dev *dev_info = dev_get_drvdata(dev);
  	struct sca3000_state *st = dev_info->dev_data;
  
  	u8 *rx;
  
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_REVID, &rx, 1);
  	if (ret < 0)
  		goto error_ret;
  	len += sprintf(buf + len,
  		       "major=%d, minor=%d\n",
  		       rx[1] & SCA3000_REVID_MAJOR_MASK,
  		       rx[1] & SCA3000_REVID_MINOR_MASK);
  	kfree(rx);
  
  error_ret:
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  
  /**
   * sca3000_show_available_measurement_modes() display available modes
   *
   * This is all read from chip specific data in the driver. Not all
   * of the sca3000 series support modes other than normal.
   **/
  static ssize_t
  sca3000_show_available_measurement_modes(struct device *dev,
  					 struct device_attribute *attr,
  					 char *buf)
  {
  	struct iio_dev *dev_info = dev_get_drvdata(dev);
  	struct sca3000_state *st = dev_info->dev_data;
  	int len = 0;
  
  	len += sprintf(buf + len, "0 - normal mode");
  	switch (st->info->option_mode_1) {
  	case SCA3000_OP_MODE_NARROW:
  		len += sprintf(buf + len, ", 1 - narrow mode");
  		break;
  	case SCA3000_OP_MODE_BYPASS:
  		len += sprintf(buf + len, ", 1 - bypass mode");
  		break;
  	}
  	switch (st->info->option_mode_2) {
  	case SCA3000_OP_MODE_WIDE:
  		len += sprintf(buf + len, ", 2 - wide mode");
  		break;
  	}
  	/* always supported */
  	len += sprintf(buf + len, " 3 - motion detection\n");
  
  	return len;
  }
  
  /**
   * sca3000_show_measurmenet_mode() sysfs read of current mode
   **/
  static ssize_t
  sca3000_show_measurement_mode(struct device *dev,
  			      struct device_attribute *attr,
  			      char *buf)
  {
  	struct iio_dev *dev_info = dev_get_drvdata(dev);
  	struct sca3000_state *st = dev_info->dev_data;
  	int len = 0, ret;
  	u8 *rx;
  
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_MODE, &rx, 1);
  	if (ret)
  		goto error_ret;
  	/* mask bottom 2 bits - only ones that are relevant */
  	rx[1] &= 0x03;
  	switch (rx[1]) {
  	case SCA3000_MEAS_MODE_NORMAL:
  		len += sprintf(buf + len, "0 - normal mode\n");
  		break;
  	case SCA3000_MEAS_MODE_MOT_DET:
  		len += sprintf(buf + len, "3 - motion detection\n");
  		break;
  	case SCA3000_MEAS_MODE_OP_1:
  		switch (st->info->option_mode_1) {
  		case SCA3000_OP_MODE_NARROW:
  			len += sprintf(buf + len, "1 - narrow mode\n");
  			break;
  		case SCA3000_OP_MODE_BYPASS:
  			len += sprintf(buf + len, "1 - bypass mode\n");
  			break;
  		}
  		break;
  	case SCA3000_MEAS_MODE_OP_2:
  		switch (st->info->option_mode_2) {
  		case SCA3000_OP_MODE_WIDE:
  			len += sprintf(buf + len, "2 - wide mode\n");
  			break;
  		}
  		break;
  	}
  
  error_ret:
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  
  /**
   * sca3000_store_measurement_mode() set the current mode
   **/
  static ssize_t
  sca3000_store_measurement_mode(struct device *dev,
  			       struct device_attribute *attr,
  			       const char *buf,
  			       size_t len)
  {
  	struct iio_dev *dev_info = dev_get_drvdata(dev);
  	struct sca3000_state *st = dev_info->dev_data;
  	int ret;
  	u8 *rx;
  	int mask = 0x03;
  	long val;
  
  	mutex_lock(&st->lock);
  	ret = strict_strtol(buf, 10, &val);
  	if (ret)
  		goto error_ret;
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_MODE, &rx, 1);
  	if (ret)
  		goto error_ret;
  	rx[1] &= ~mask;
  	rx[1] |= (val & mask);
  	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE, rx[1]);
  	if (ret)
  		goto error_free_rx;
  	mutex_unlock(&st->lock);
  
  	return len;
  
  error_free_rx:
  	kfree(rx);
  error_ret:
  	mutex_unlock(&st->lock);
  
  	return ret;
  }
  
  
  /* Not even vaguely standard attributes so defined here rather than
   * in the relevant IIO core headers
   */
  static IIO_DEVICE_ATTR(measurement_mode_available, S_IRUGO,
  		       sca3000_show_available_measurement_modes,
  		       NULL, 0);
  
  static IIO_DEVICE_ATTR(measurement_mode, S_IRUGO | S_IWUSR,
  		       sca3000_show_measurement_mode,
  		       sca3000_store_measurement_mode,
  		       0);
  
  /* More standard attributes */
  
  static IIO_DEV_ATTR_NAME(sca3000_show_name);
  static IIO_DEV_ATTR_REV(sca3000_show_rev);
  static IIO_DEVICE_ATTR(accel_scale, S_IRUGO, sca3000_show_scale,
  		       NULL, 0);
  
  static IIO_DEV_ATTR_ACCEL_X(sca3000_read_13bit_signed,
  			    SCA3000_REG_ADDR_X_MSB);
  static IIO_DEV_ATTR_ACCEL_Y(sca3000_read_13bit_signed,
  			    SCA3000_REG_ADDR_Y_MSB);
  static IIO_DEV_ATTR_ACCEL_Z(sca3000_read_13bit_signed,
  			    SCA3000_REG_ADDR_Z_MSB);
  
  
  /**
   * sca3000_read_av_freq() sysfs function to get available frequencies
   *
   * The later modes are only relevant to the ring buffer - and depend on current
   * mode. Note that data sheet gives rather wide tolerances for these so integer
   * division will give good enough answer and not all chips have them specified
   * at all.
   **/
  static ssize_t sca3000_read_av_freq(struct device *dev,
  			     struct device_attribute *attr,
  			     char *buf)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  	int len = 0, ret;
  	u8 *rx;
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_MODE, &rx, 1);
  	mutex_unlock(&st->lock);
  	if (ret)
  		goto error_ret;
  	rx[1] &= 0x03;
  	switch (rx[1]) {
  	case SCA3000_MEAS_MODE_NORMAL:
  		len += sprintf(buf + len, "%d %d %d\n",
  			       st->info->measurement_mode_freq,
  			       st->info->measurement_mode_freq/2,
  			       st->info->measurement_mode_freq/4);
  		break;
  	case SCA3000_MEAS_MODE_OP_1:
  		len += sprintf(buf + len, "%d %d %d\n",
  			       st->info->option_mode_1_freq,
  			       st->info->option_mode_1_freq/2,
  			       st->info->option_mode_1_freq/4);
  		break;
  	case SCA3000_MEAS_MODE_OP_2:
  		len += sprintf(buf + len, "%d %d %d\n",
  			       st->info->option_mode_2_freq,
  			       st->info->option_mode_2_freq/2,
  			       st->info->option_mode_2_freq/4);
  		break;
  	}
  	kfree(rx);
  	return len;
  error_ret:
  	return ret;
  }
  /**
   * __sca3000_get_base_frequency() obtain mode specific base frequency
   *
   * lock must be held
   **/
  static inline int __sca3000_get_base_freq(struct sca3000_state *st,
  					  const struct sca3000_chip_info *info,
  					  int *base_freq)
  {
  	int ret;
  	u8 *rx;
  
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_MODE, &rx, 1);
  	if (ret)
  		goto error_ret;
  	switch (0x03 & rx[1]) {
  	case SCA3000_MEAS_MODE_NORMAL:
  		*base_freq = info->measurement_mode_freq;
  		break;
  	case SCA3000_MEAS_MODE_OP_1:
  		*base_freq = info->option_mode_1_freq;
  		break;
  	case SCA3000_MEAS_MODE_OP_2:
  		*base_freq = info->option_mode_2_freq;
  		break;
  	}
  	kfree(rx);
  error_ret:
  	return ret;
  }
  
  /**
   * sca3000_read_frequency() sysfs interface to get the current frequency
   **/
  static ssize_t sca3000_read_frequency(struct device *dev,
  			       struct device_attribute *attr,
  			       char *buf)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  	int ret, len = 0, base_freq = 0;
  	u8 *rx;
  	mutex_lock(&st->lock);
  	ret = __sca3000_get_base_freq(st, st->info, &base_freq);
  	if (ret)
  		goto error_ret_mut;
  	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL, &rx);
  	mutex_unlock(&st->lock);
  	if (ret)
  		goto error_ret;
  	if (base_freq > 0)
  		switch (rx[1]&0x03) {
  		case 0x00:
  		case 0x03:
  			len = sprintf(buf, "%d\n", base_freq);
  			break;
  		case 0x01:
  			len = sprintf(buf, "%d\n", base_freq/2);
  			break;
  		case 0x02:
  			len = sprintf(buf, "%d\n", base_freq/4);
  			break;
  	}
  	kfree(rx);
  	return len;
  error_ret_mut:
  	mutex_unlock(&st->lock);
  error_ret:
  	return ret;
  }
  
  /**
   * sca3000_set_frequency() sysfs interface to set the current frequency
   **/
  static ssize_t sca3000_set_frequency(struct device *dev,
  			      struct device_attribute *attr,
  			      const char *buf,
  			      size_t len)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  	int ret, base_freq = 0;
  	u8 *rx;
  	long val;
  
  	ret = strict_strtol(buf, 10, &val);
  	if (ret)
  		return ret;
  
  	mutex_lock(&st->lock);
  	/* What mode are we in? */
  	ret = __sca3000_get_base_freq(st, st->info, &base_freq);
  	if (ret)
  		goto error_free_lock;
  
  	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL, &rx);
  	if (ret)
  		goto error_free_lock;
  	/* clear the bits */
  	rx[1] &= ~0x03;
  
  	if (val == base_freq/2) {
  		rx[1] |= SCA3000_OUT_CTRL_BUF_DIV_2;
  	} else if (val == base_freq/4) {
  		rx[1] |= SCA3000_OUT_CTRL_BUF_DIV_4;
  	} else if (val != base_freq) {
  		ret = -EINVAL;
  		goto error_free_lock;
  	}
  	ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL, rx[1]);
  error_free_lock:
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  
  /* Should only really be registered if ring buffer support is compiled in.
   * Does no harm however and doing it right would add a fair bit of complexity
   */
  static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(sca3000_read_av_freq);
  
  static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
  			      sca3000_read_frequency,
  			      sca3000_set_frequency);
  
  
  /**
   * sca3000_read_temp() sysfs interface to get the temperature when available
   *
  * The alignment of data in here is downright odd. See data sheet.
  * Converting this into a meaningful value is left to inline functions in
  * userspace part of header.
  **/
  static ssize_t sca3000_read_temp(struct device *dev,
  				 struct device_attribute *attr,
  				 char *buf)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  	int len = 0, ret;
  	int val;
  	u8 *rx;
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_TEMP_MSB, &rx, 2);
  	if (ret < 0)
  		goto error_ret;
  	val = ((rx[1]&0x3F) << 3) | ((rx[2] & 0xE0) >> 5);
  	len += sprintf(buf + len, "%d\n", val);
  	kfree(rx);
  
  	return len;
  
  error_ret:
  	return ret;
  }
  static IIO_DEV_ATTR_TEMP_RAW(sca3000_read_temp);
  
  static IIO_CONST_ATTR(temp_scale, "0.555556");
  static IIO_CONST_ATTR(temp_offset, "-214.6");
  
  /**
   * sca3000_show_thresh() sysfs query of a threshold
   **/
  static ssize_t sca3000_show_thresh(struct device *dev,
  				   struct device_attribute *attr,
  				   char *buf)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
  	int len = 0, ret;
  	u8 *rx;
  
  	mutex_lock(&st->lock);
  	ret = sca3000_read_ctrl_reg(st,
  				    this_attr->address,
  				    &rx);
  	mutex_unlock(&st->lock);
  	if (ret)
  		return ret;
  	len += sprintf(buf + len, "%d\n", rx[1]);
  	kfree(rx);
  
  	return len;
  }
  
  /**
   * sca3000_write_thresh() sysfs control of threshold
   **/
  static ssize_t sca3000_write_thresh(struct device *dev,
  				    struct device_attribute *attr,
  				    const char *buf,
  				    size_t len)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
  	int ret;
  	long val;
  
  	ret = strict_strtol(buf, 10, &val);
  	if (ret)
  		return ret;
  	mutex_lock(&st->lock);
  	ret = sca3000_write_ctrl_reg(st, this_attr->address, val);
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  
  static IIO_DEVICE_ATTR(accel_x_mag_either_rising_value,
  		S_IRUGO | S_IWUSR,
  		sca3000_show_thresh,
  		sca3000_write_thresh,
  		SCA3000_REG_CTRL_SEL_MD_X_TH);
  
  static IIO_DEVICE_ATTR(accel_y_mag_either_rising_value,
  		S_IRUGO | S_IWUSR,
  		sca3000_show_thresh,
  		sca3000_write_thresh,
  		SCA3000_REG_CTRL_SEL_MD_Y_TH);
  
  static IIO_DEVICE_ATTR(accel_z_mag_either_rising_value,
  		S_IRUGO | S_IWUSR,
  		sca3000_show_thresh,
  		sca3000_write_thresh,
  		SCA3000_REG_CTRL_SEL_MD_Z_TH);
  
  static struct attribute *sca3000_attributes[] = {
  	&iio_dev_attr_name.dev_attr.attr,
  	&iio_dev_attr_revision.dev_attr.attr,
  	&iio_dev_attr_accel_scale.dev_attr.attr,
  	&iio_dev_attr_accel_x_raw.dev_attr.attr,
  	&iio_dev_attr_accel_y_raw.dev_attr.attr,
  	&iio_dev_attr_accel_z_raw.dev_attr.attr,
  	&iio_dev_attr_measurement_mode_available.dev_attr.attr,
  	&iio_dev_attr_measurement_mode.dev_attr.attr,
  	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
  	&iio_dev_attr_sampling_frequency.dev_attr.attr,
  	NULL,
  };
  
  static struct attribute *sca3000_attributes_with_temp[] = {
  	&iio_dev_attr_name.dev_attr.attr,
  	&iio_dev_attr_revision.dev_attr.attr,
  	&iio_dev_attr_accel_scale.dev_attr.attr,
  	&iio_dev_attr_accel_x_raw.dev_attr.attr,
  	&iio_dev_attr_accel_y_raw.dev_attr.attr,
  	&iio_dev_attr_accel_z_raw.dev_attr.attr,
  	&iio_dev_attr_measurement_mode_available.dev_attr.attr,
  	&iio_dev_attr_measurement_mode.dev_attr.attr,
  	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
  	&iio_dev_attr_sampling_frequency.dev_attr.attr,
  	/* Only present if temp sensor is */
  	&iio_dev_attr_temp_raw.dev_attr.attr,
  	&iio_const_attr_temp_offset.dev_attr.attr,
  	&iio_const_attr_temp_scale.dev_attr.attr,
  	NULL,
  };
  
  static const struct attribute_group sca3000_attribute_group = {
  	.attrs = sca3000_attributes,
  };
  
  static const struct attribute_group sca3000_attribute_group_with_temp = {
  	.attrs = sca3000_attributes_with_temp,
  };
  
  /* RING RELATED interrupt handler */
  /* depending on event, push to the ring buffer event chrdev or the event one */
  
  /**
   * sca3000_interrupt_handler_bh() - handling ring and non ring events
   *
   * This function is complicated by the fact that the devices can signify ring
   * and non ring events via the same interrupt line and they can only
   * be distinguished via a read of the relevant status register.
   **/
  static void sca3000_interrupt_handler_bh(struct work_struct *work_s)
  {
  	struct sca3000_state *st
  		= container_of(work_s, struct sca3000_state,
  			       interrupt_handler_ws);
  	u8 *rx;
  	int ret;
  
  	/* Could lead if badly timed to an extra read of status reg,
  	 * but ensures no interrupt is missed.
  	 */
  	enable_irq(st->us->irq);
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_INT_STATUS,
  				&rx, 1);
  	mutex_unlock(&st->lock);
  	if (ret)
  		goto done;
  
  	sca3000_ring_int_process(rx[1], st->indio_dev->ring);
  
  	if (rx[1] & SCA3000_INT_STATUS_FREE_FALL)
  		iio_push_event(st->indio_dev, 0,
  			       IIO_EVENT_CODE_FREE_FALL,
  			       st->last_timestamp);
  
  	if (rx[1] & SCA3000_INT_STATUS_Y_TRIGGER)
  		iio_push_event(st->indio_dev, 0,
  			       IIO_EVENT_CODE_ACCEL_Y_HIGH,
  			       st->last_timestamp);
  
  	if (rx[1] & SCA3000_INT_STATUS_X_TRIGGER)
  		iio_push_event(st->indio_dev, 0,
  			       IIO_EVENT_CODE_ACCEL_X_HIGH,
  			       st->last_timestamp);
  
  	if (rx[1] & SCA3000_INT_STATUS_Z_TRIGGER)
  		iio_push_event(st->indio_dev, 0,
  			       IIO_EVENT_CODE_ACCEL_Z_HIGH,
  			       st->last_timestamp);
  
  done:
  	kfree(rx);
  	return;
  }
  
  /**
   * sca3000_handler_th() handles all interrupt events from device
   *
   * These devices deploy unified interrupt status registers meaning
   * all interrupts must be handled together
   **/
  static int sca3000_handler_th(struct iio_dev *dev_info,
  			      int index,
  			      s64 timestamp,
  			      int no_test)
  {
  	struct sca3000_state *st = dev_info->dev_data;
  
  	st->last_timestamp = timestamp;
  	schedule_work(&st->interrupt_handler_ws);
  
  	return 0;
  }
  
  /**
   * sca3000_query_mo_det() is motion detection enabled for this axis
   *
   * First queries if motion detection is enabled and then if this axis is
   * on.
   **/
  static ssize_t sca3000_query_mo_det(struct device *dev,
  				    struct device_attribute *attr,
  				    char *buf)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev->parent);
  	struct sca3000_state *st = indio_dev->dev_data;
  	struct iio_event_attr *this_attr = to_iio_event_attr(attr);
  	int ret, len = 0;
  	u8 *rx;
  	u8 protect_mask = 0x03;
  
  	/* read current value of mode register */
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_MODE, &rx, 1);
  	if (ret)
  		goto error_ret;
  
  	if ((rx[1]&protect_mask) != SCA3000_MEAS_MODE_MOT_DET)
  		len += sprintf(buf + len, "0\n");
  	else {
  		kfree(rx);
  		ret = sca3000_read_ctrl_reg(st,
  					    SCA3000_REG_CTRL_SEL_MD_CTRL,
  					    &rx);
  		if (ret)
  			goto error_ret;
  		/* only supporting logical or's for now */
  		len += sprintf(buf + len, "%d\n",
  			       (rx[1] & this_attr->mask) ? 1 : 0);
  	}
  	kfree(rx);
  error_ret:
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  /**
   * sca3000_query_free_fall_mode() is free fall mode enabled
   **/
  static ssize_t sca3000_query_free_fall_mode(struct device *dev,
  					    struct device_attribute *attr,
  					    char *buf)
  {
  	int ret, len;
  	u8 *rx;
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_MODE, &rx, 1);
  	mutex_unlock(&st->lock);
  	if (ret)
  		return ret;
  	len = sprintf(buf, "%d\n",
  		      !!(rx[1] & SCA3000_FREE_FALL_DETECT));
  	kfree(rx);
  
  	return len;
  }
  /**
   * sca3000_query_ring_int() is the hardware ring status interrupt enabled
   **/
  static ssize_t sca3000_query_ring_int(struct device *dev,
  				      struct device_attribute *attr,
  				      char *buf)
  {
  	struct iio_event_attr *this_attr = to_iio_event_attr(attr);
  	int ret, len;
  	u8 *rx;
  	struct iio_dev *indio_dev = dev_get_drvdata(dev->parent);
  	struct sca3000_state *st = indio_dev->dev_data;
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_INT_MASK, &rx, 1);
  	mutex_unlock(&st->lock);
  	if (ret)
  		return ret;
  	len = sprintf(buf, "%d\n", (rx[1] & this_attr->mask) ? 1 : 0);
  	kfree(rx);
  
  	return len;
  }
  /**
   * sca3000_set_ring_int() set state of ring status interrupt
   **/
  static ssize_t sca3000_set_ring_int(struct device *dev,
  				      struct device_attribute *attr,
  				      const char *buf,
  				      size_t len)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev->parent);
  	struct sca3000_state *st = indio_dev->dev_data;
  	struct iio_event_attr *this_attr = to_iio_event_attr(attr);
  
  	long val;
  	int ret;
  	u8 *rx;
  
  	mutex_lock(&st->lock);
  	ret = strict_strtol(buf, 10, &val);
  	if (ret)
  		goto error_ret;
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_INT_MASK, &rx, 1);
  	if (ret)
  		goto error_ret;
  	if (val)
  		ret = sca3000_write_reg(st,
  					SCA3000_REG_ADDR_INT_MASK,
  					rx[1] | this_attr->mask);
  	else
  		ret = sca3000_write_reg(st,
  					SCA3000_REG_ADDR_INT_MASK,
  					rx[1] & ~this_attr->mask);
  	kfree(rx);
  error_ret:
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  
  /**
   * sca3000_set_free_fall_mode() simple on off control for free fall int
   *
   * In these chips the free fall detector should send an interrupt if
   * the device falls more than 25cm.  This has not been tested due
   * to fragile wiring.
   **/
  
  static ssize_t sca3000_set_free_fall_mode(struct device *dev,
  					  struct device_attribute *attr,
  					  const char *buf,
  					  size_t len)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
  	struct sca3000_state *st = indio_dev->dev_data;
  	long val;
  	int ret;
  	u8 *rx;
  	u8 protect_mask = SCA3000_FREE_FALL_DETECT;
  
  	mutex_lock(&st->lock);
  	ret = strict_strtol(buf, 10, &val);
  	if (ret)
  		goto error_ret;
  
  	/* read current value of mode register */
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_MODE, &rx, 1);
  	if (ret)
  		goto error_ret;
  
  	/*if off and should be on*/
  	if (val && !(rx[1] & protect_mask))
  		ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
  					(rx[1] | SCA3000_FREE_FALL_DETECT));
  	/* if on and should be off */
  	else if (!val && (rx[1]&protect_mask))
  		ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
  					(rx[1] & ~protect_mask));
  
  	kfree(rx);
  error_ret:
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  
  /**
   * sca3000_set_mo_det() simple on off control for motion detector
   *
   * This is a per axis control, but enabling any will result in the
   * motion detector unit being enabled.
   * N.B. enabling motion detector stops normal data acquisition.
   * There is a complexity in knowing which mode to return to when
   * this mode is disabled.  Currently normal mode is assumed.
   **/
  static ssize_t sca3000_set_mo_det(struct device *dev,
  				  struct device_attribute *attr,
  				  const char *buf,
  				  size_t len)
  {
  	struct iio_dev *indio_dev = dev_get_drvdata(dev->parent);
  	struct sca3000_state *st = indio_dev->dev_data;
  	struct iio_event_attr *this_attr = to_iio_event_attr(attr);
  	long val;
  	int ret;
  	u8 *rx;
  	u8 protect_mask = 0x03;
  	ret = strict_strtol(buf, 10, &val);
  	if (ret)
  		return ret;
  
  	mutex_lock(&st->lock);
  	/* First read the motion detector config to find out if
  	 * this axis is on*/
  	ret = sca3000_read_ctrl_reg(st,
  				    SCA3000_REG_CTRL_SEL_MD_CTRL,
  				    &rx);
  	if (ret)
  		goto exit_point;
  	/* Off and should be on */
  	if (val && !(rx[1] & this_attr->mask)) {
  		ret = sca3000_write_ctrl_reg(st,
  					     SCA3000_REG_CTRL_SEL_MD_CTRL,
  					     rx[1] | this_attr->mask);
  		if (ret)
  			goto exit_point_free_rx;
  		st->mo_det_use_count++;
  	} else if (!val && (rx[1]&this_attr->mask)) {
  		ret = sca3000_write_ctrl_reg(st,
  					     SCA3000_REG_CTRL_SEL_MD_CTRL,
  					     rx[1] & ~(this_attr->mask));
  		if (ret)
  			goto exit_point_free_rx;
  		st->mo_det_use_count--;
  	} else /* relies on clean state for device on boot */
  		goto exit_point_free_rx;
  	kfree(rx);
  	/* read current value of mode register */
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_MODE, &rx, 1);
  	if (ret)
  		goto exit_point;
  	/*if off and should be on*/
  	if ((st->mo_det_use_count)
  	    && ((rx[1]&protect_mask) != SCA3000_MEAS_MODE_MOT_DET))
  		ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
  					(rx[1] & ~protect_mask)
  					| SCA3000_MEAS_MODE_MOT_DET);
  	/* if on and should be off */
  	else if (!(st->mo_det_use_count)
  		 && ((rx[1]&protect_mask) == SCA3000_MEAS_MODE_MOT_DET))
  		ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
  					(rx[1] & ~protect_mask));
  exit_point_free_rx:
  	kfree(rx);
  exit_point:
  	mutex_unlock(&st->lock);
  
  	return ret ? ret : len;
  }
  
  /* Shared event handler for all events as single event status register */
  IIO_EVENT_SH(all, &sca3000_handler_th);
  
  /* Free fall detector related event attribute */
  IIO_EVENT_ATTR_FREE_FALL_DETECT_SH(iio_event_all,
  				   sca3000_query_free_fall_mode,
  				   sca3000_set_free_fall_mode,
  				   0)
  
  /* Motion detector related event attributes */
  IIO_EVENT_ATTR_SH(accel_x_mag_either_rising_en,
  		  iio_event_all,
  		  sca3000_query_mo_det,
  		  sca3000_set_mo_det,
  		  SCA3000_MD_CTRL_OR_X);
  
  IIO_EVENT_ATTR_SH(accel_y_mag_either_rising_en,
  		  iio_event_all,
  		  sca3000_query_mo_det,
  		  sca3000_set_mo_det,
  		  SCA3000_MD_CTRL_OR_Y);
  
  IIO_EVENT_ATTR_SH(accel_z_mag_either_rising_en,
  		  iio_event_all,
  		  sca3000_query_mo_det,
  		  sca3000_set_mo_det,
  		  SCA3000_MD_CTRL_OR_Z);
  
  /* Hardware ring buffer related event attributes */
  IIO_EVENT_ATTR_RING_50_FULL_SH(iio_event_all,
  			       sca3000_query_ring_int,
  			       sca3000_set_ring_int,
  			       SCA3000_INT_MASK_RING_HALF);
  
  IIO_EVENT_ATTR_RING_75_FULL_SH(iio_event_all,
  			       sca3000_query_ring_int,
  			       sca3000_set_ring_int,
  			       SCA3000_INT_MASK_RING_THREE_QUARTER);
  
  static struct attribute *sca3000_event_attributes[] = {
  	&iio_event_attr_free_fall.dev_attr.attr,
  	&iio_event_attr_accel_x_mag_either_rising_en.dev_attr.attr,
  	&iio_event_attr_accel_y_mag_either_rising_en.dev_attr.attr,
  	&iio_event_attr_accel_z_mag_either_rising_en.dev_attr.attr,
  	&iio_event_attr_ring_50_full.dev_attr.attr,
  	&iio_event_attr_ring_75_full.dev_attr.attr,
  	&iio_dev_attr_accel_x_mag_either_rising_value.dev_attr.attr,
  	&iio_dev_attr_accel_y_mag_either_rising_value.dev_attr.attr,
  	&iio_dev_attr_accel_z_mag_either_rising_value.dev_attr.attr,
  	NULL,
  };
  
  static struct attribute_group sca3000_event_attribute_group = {
  	.attrs = sca3000_event_attributes,
  };
  
  /**
   * sca3000_clean_setup() get the device into a predictable state
   *
   * Devices use flash memory to store many of the register values
   * and hence can come up in somewhat unpredictable states.
   * Hence reset everything on driver load.
    **/
  static int sca3000_clean_setup(struct sca3000_state *st)
  {
  	int ret;
  	u8 *rx;
  
  	mutex_lock(&st->lock);
  	/* Ensure all interrupts have been acknowledged */
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_INT_STATUS, &rx, 1);
  	if (ret)
  		goto error_ret;
  	kfree(rx);
  
  	/* Turn off all motion detection channels */
  	ret = sca3000_read_ctrl_reg(st,
  				    SCA3000_REG_CTRL_SEL_MD_CTRL,
  				    &rx);
  	if (ret)
  		goto error_ret;
  	ret = sca3000_write_ctrl_reg(st,
  				     SCA3000_REG_CTRL_SEL_MD_CTRL,
  				     rx[1] & SCA3000_MD_CTRL_PROT_MASK);
  	kfree(rx);
  	if (ret)
  		goto error_ret;
  
  	/* Disable ring buffer */
  	sca3000_read_ctrl_reg(st,
  			      SCA3000_REG_CTRL_SEL_OUT_CTRL,
  			      &rx);
  	/* Frequency of ring buffer sampling deliberately restricted to make
  	 * debugging easier - add control of this later */
  	ret = sca3000_write_ctrl_reg(st,
  				     SCA3000_REG_CTRL_SEL_OUT_CTRL,
  				     (rx[1] & SCA3000_OUT_CTRL_PROT_MASK)
  				     | SCA3000_OUT_CTRL_BUF_X_EN
  				     | SCA3000_OUT_CTRL_BUF_Y_EN
  				     | SCA3000_OUT_CTRL_BUF_Z_EN
  				     | SCA3000_OUT_CTRL_BUF_DIV_4);
  	kfree(rx);
  
  	if (ret)
  		goto error_ret;
  	/* Enable interrupts, relevant to mode and set up as active low */
  	ret = sca3000_read_data(st,
  			  SCA3000_REG_ADDR_INT_MASK,
  			  &rx, 1);
  	if (ret)
  		goto error_ret;
  	ret = sca3000_write_reg(st,
  				SCA3000_REG_ADDR_INT_MASK,
  				(rx[1] & SCA3000_INT_MASK_PROT_MASK)
  				| SCA3000_INT_MASK_ACTIVE_LOW);
  	kfree(rx);
  	if (ret)
  		goto error_ret;
  	/* Select normal measurement mode, free fall off, ring off */
  	/* Ring in 12 bit mode - it is fine to overwrite reserved bits 3,5
  	 * as that occurs in one of the example on the datasheet */
  	ret = sca3000_read_data(st,
  			  SCA3000_REG_ADDR_MODE,
  			  &rx, 1);
  	if (ret)
  		goto error_ret;
  	ret = sca3000_write_reg(st,
  				SCA3000_REG_ADDR_MODE,
  				(rx[1] & SCA3000_MODE_PROT_MASK));
  	kfree(rx);
  	st->bpse = 11;
  
  error_ret:
  	mutex_unlock(&st->lock);
  	return ret;
  }
  
  static int __devinit __sca3000_probe(struct spi_device *spi,
  				     enum sca3000_variant variant)
  {
  	int ret, regdone = 0;
  	struct sca3000_state *st;
  
  	st = kzalloc(sizeof(struct sca3000_state), GFP_KERNEL);
  	if (st == NULL) {
  		ret = -ENOMEM;
  		goto error_ret;
  	}
  	spi_set_drvdata(spi, st);
  
  	st->tx = kmalloc(sizeof(*st->tx)*6, GFP_KERNEL);
  	if (st->tx == NULL) {
  		ret = -ENOMEM;
  		goto error_clear_st;
  	}
  	st->rx = kmalloc(sizeof(*st->rx)*3, GFP_KERNEL);
  	if (st->rx == NULL) {
  		ret = -ENOMEM;
  		goto error_free_tx;
  	}
  	st->us = spi;
  	mutex_init(&st->lock);
  	st->info = &sca3000_spi_chip_info_tbl[variant];
  
  	st->indio_dev = iio_allocate_device();
  	if (st->indio_dev == NULL) {
  		ret = -ENOMEM;
  		goto error_free_rx;
  	}
  
  	st->indio_dev->dev.parent = &spi->dev;
  	st->indio_dev->num_interrupt_lines = 1;
  	st->indio_dev->event_attrs = &sca3000_event_attribute_group;
  	if (st->info->temp_output)
  		st->indio_dev->attrs = &sca3000_attribute_group_with_temp;
  	else
  		st->indio_dev->attrs = &sca3000_attribute_group;
  	st->indio_dev->dev_data = (void *)(st);
  	st->indio_dev->modes = INDIO_DIRECT_MODE;
  
  	sca3000_configure_ring(st->indio_dev);
  
  	ret = iio_device_register(st->indio_dev);
  	if (ret < 0)
  		goto error_free_dev;
  	regdone = 1;
  	ret = iio_ring_buffer_register(st->indio_dev->ring, 0);
  	if (ret < 0)
  		goto error_unregister_dev;
  	if (spi->irq && gpio_is_valid(irq_to_gpio(spi->irq)) > 0) {
  		INIT_WORK(&st->interrupt_handler_ws,
  			  sca3000_interrupt_handler_bh);
  		ret = iio_register_interrupt_line(spi->irq,
  						  st->indio_dev,
  						  0,
  						  IRQF_TRIGGER_FALLING,
  						  "sca3000");
  		if (ret)
  			goto error_unregister_ring;
  		/* RFC
  		 * Probably a common situation.  All interrupts need an ack
  		 * and there is only one handler so the complicated list system
  		 * is overkill.  At very least a simpler registration method
  		 * might be worthwhile.
  		 */
  		iio_add_event_to_list(
  			iio_event_attr_accel_z_mag_either_rising_en.listel,
  			&st->indio_dev
  			->interrupts[0]->ev_list);
  	}
  	sca3000_register_ring_funcs(st->indio_dev);
  	ret = sca3000_clean_setup(st);
  	if (ret)
  		goto error_unregister_interrupt_line;
  	return 0;
  
  error_unregister_interrupt_line:
  	if (spi->irq && gpio_is_valid(irq_to_gpio(spi->irq)) > 0)
  		iio_unregister_interrupt_line(st->indio_dev, 0);
  error_unregister_ring:
  	iio_ring_buffer_unregister(st->indio_dev->ring);
  error_unregister_dev:
  error_free_dev:
  	if (regdone)
  		iio_device_unregister(st->indio_dev);
  	else
  		iio_free_device(st->indio_dev);
  error_free_rx:
  	kfree(st->rx);
  error_free_tx:
  	kfree(st->tx);
  error_clear_st:
  	kfree(st);
  error_ret:
  	return ret;
  }
  
  static int sca3000_stop_all_interrupts(struct sca3000_state *st)
  {
  	int ret;
  	u8 *rx;
  
  	mutex_lock(&st->lock);
  	ret = sca3000_read_data(st, SCA3000_REG_ADDR_INT_MASK, &rx, 1);
  	if (ret)
  		goto error_ret;
  	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_INT_MASK,
  				(rx[1] & ~(SCA3000_INT_MASK_RING_THREE_QUARTER
  					   | SCA3000_INT_MASK_RING_HALF
  					   | SCA3000_INT_MASK_ALL_INTS)));
  error_ret:
  	kfree(rx);
  	return ret;
  
  }
  
  static int sca3000_remove(struct spi_device *spi)
  {
  	struct sca3000_state *st =  spi_get_drvdata(spi);
  	struct iio_dev *indio_dev = st->indio_dev;
  	int ret;
  	/* Must ensure no interrupts can be generated after this!*/
  	ret = sca3000_stop_all_interrupts(st);
  	if (ret)
  		return ret;
  	if (spi->irq && gpio_is_valid(irq_to_gpio(spi->irq)) > 0)
  		iio_unregister_interrupt_line(indio_dev, 0);
  	iio_ring_buffer_unregister(indio_dev->ring);
  	sca3000_unconfigure_ring(indio_dev);
  	iio_device_unregister(indio_dev);
  
  	kfree(st->tx);
  	kfree(st->rx);
  	kfree(st);
  
  	return 0;
  }
  
  /* These macros save on an awful lot of repeated code */
  #define SCA3000_VARIANT_PROBE(_name)				\
  	static int __devinit					\
  	sca3000_##_name##_probe(struct spi_device *spi)		\
  	{							\
  		return __sca3000_probe(spi, _name);		\
  	}
  
  #define SCA3000_VARIANT_SPI_DRIVER(_name)			\
  	struct spi_driver sca3000_##_name##_driver = {		\
  		.driver = {					\
  			.name = "sca3000_" #_name,		\
  			.owner = THIS_MODULE,			\
  		},						\
  		.probe = sca3000_##_name##_probe,		\
  		.remove = __devexit_p(sca3000_remove),		\
  	}
  
  SCA3000_VARIANT_PROBE(d01);
  static SCA3000_VARIANT_SPI_DRIVER(d01);
  
  SCA3000_VARIANT_PROBE(e02);
  static SCA3000_VARIANT_SPI_DRIVER(e02);
  
  SCA3000_VARIANT_PROBE(e04);
  static SCA3000_VARIANT_SPI_DRIVER(e04);
  
  SCA3000_VARIANT_PROBE(e05);
  static SCA3000_VARIANT_SPI_DRIVER(e05);
  
  static __init int sca3000_init(void)
  {
  	int ret;
  
  	ret = spi_register_driver(&sca3000_d01_driver);
  	if (ret)
  		goto error_ret;
  	ret = spi_register_driver(&sca3000_e02_driver);
  	if (ret)
  		goto error_unreg_d01;
  	ret = spi_register_driver(&sca3000_e04_driver);
  	if (ret)
  		goto error_unreg_e02;
  	ret = spi_register_driver(&sca3000_e05_driver);
  	if (ret)
  		goto error_unreg_e04;
  
  	return 0;
  
  error_unreg_e04:
  	spi_unregister_driver(&sca3000_e04_driver);
  error_unreg_e02:
  	spi_unregister_driver(&sca3000_e02_driver);
  error_unreg_d01:
  	spi_unregister_driver(&sca3000_d01_driver);
  error_ret:
  
  	return ret;
  }
  
  static __exit void sca3000_exit(void)
  {
  	spi_unregister_driver(&sca3000_e05_driver);
  	spi_unregister_driver(&sca3000_e04_driver);
  	spi_unregister_driver(&sca3000_e02_driver);
  	spi_unregister_driver(&sca3000_d01_driver);
  }
  
  module_init(sca3000_init);
  module_exit(sca3000_exit);
  
  MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
  MODULE_DESCRIPTION("VTI SCA3000 Series Accelerometers SPI driver");
  MODULE_LICENSE("GPL v2");
  