drivers/staging/iio/accel/lis3l02dq_core.c

/*
 * lis3l02dq.c	support STMicroelectronics LISD02DQ
 *		3d 2g Linear Accelerometers via SPI
 *
 * Copyright (c) 2007 Jonathan Cameron <jic23@cam.ac.uk>
 *
 * 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.
 *
 * Settings:
 * 16 bit left justified mode used.
 */

#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <linux/workqueue.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 "../iio.h"
#include "../sysfs.h"
#include "../ring_generic.h"
#include "../ring_sw.h"

#include "accel.h"

#include "lis3l02dq.h"

/* At the moment the spi framework doesn't allow global setting of cs_change.
 * It's in the likely to be added comment at the top of spi.h.
 * This means that use cannot be made of spi_write etc.
 */

/**
 * lis3l02dq_spi_read_reg_8() - read single byte from a single register
 * @indio_dev: iio_dev for this actual device
 * @reg_address: the address of the register to be read
 * @val: pass back the resulting value
 **/
int lis3l02dq_spi_read_reg_8(struct iio_dev *indio_dev,
			     u8 reg_address, u8 *val)
{
	struct iio_sw_ring_helper_state *h = iio_dev_get_devdata(indio_dev);
	struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);
	struct spi_message msg;
	int ret;
	struct spi_transfer xfer = {
		.tx_buf = st->tx,
		.rx_buf = st->rx,
		.bits_per_word = 8,
		.len = 2,
	};

	mutex_lock(&st->buf_lock);
	st->tx[0] = LIS3L02DQ_READ_REG(reg_address);
	st->tx[1] = 0;

	spi_message_init(&msg);
	spi_message_add_tail(&xfer, &msg);
	ret = spi_sync(st->us, &msg);
	*val = st->rx[1];
	mutex_unlock(&st->buf_lock);

	return ret;
}

/**
 * lis3l02dq_spi_write_reg_8() - write single byte to a register
 * @indio_dev: iio_dev for this device
 * @reg_address: the address of the register to be written
 * @val: the value to write
 **/
int lis3l02dq_spi_write_reg_8(struct iio_dev *indio_dev,
			      u8 reg_address,
			      u8 *val)
{
	int ret;
	struct iio_sw_ring_helper_state *h
		= iio_dev_get_devdata(indio_dev);
	struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);

	mutex_lock(&st->buf_lock);
	st->tx[0] = LIS3L02DQ_WRITE_REG(reg_address);
	st->tx[1] = *val;
	ret = spi_write(st->us, st->tx, 2);
	mutex_unlock(&st->buf_lock);

	return ret;
}

/**
 * lisl302dq_spi_write_reg_s16() - write 2 bytes to a pair of registers
 * @indio_dev: iio_dev for this device
 * @lower_reg_address: the address of the lower of the two registers.
 *               Second register is assumed to have address one greater.
 * @value: value to be written
 **/
static int lis3l02dq_spi_write_reg_s16(struct iio_dev *indio_dev,
				       u8 lower_reg_address,
				       s16 value)
{
	int ret;
	struct spi_message msg;
	struct iio_sw_ring_helper_state *h
		= iio_dev_get_devdata(indio_dev);
	struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);
	struct spi_transfer xfers[] = { {
			.tx_buf = st->tx,
			.bits_per_word = 8,
			.len = 2,
			.cs_change = 1,
		}, {
			.tx_buf = st->tx + 2,
			.bits_per_word = 8,
			.len = 2,
		},
	};

	mutex_lock(&st->buf_lock);
	st->tx[0] = LIS3L02DQ_WRITE_REG(lower_reg_address);
	st->tx[1] = value & 0xFF;
	st->tx[2] = LIS3L02DQ_WRITE_REG(lower_reg_address + 1);
	st->tx[3] = (value >> 8) & 0xFF;

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	spi_message_add_tail(&xfers[1], &msg);
	ret = spi_sync(st->us, &msg);
	mutex_unlock(&st->buf_lock);

	return ret;
}

static int lis3l02dq_read_reg_s16(struct iio_dev *indio_dev,
				  u8 lower_reg_address,
				  int *val)
{
	struct iio_sw_ring_helper_state *h
		= iio_dev_get_devdata(indio_dev);
	struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);

	struct spi_message msg;
	int ret;
	s16 tempval;
	struct spi_transfer xfers[] = { {
			.tx_buf = st->tx,
			.rx_buf = st->rx,
			.bits_per_word = 8,
			.len = 2,
			.cs_change = 1,
		}, {
			.tx_buf = st->tx + 2,
			.rx_buf = st->rx + 2,
			.bits_per_word = 8,
			.len = 2,
		},
	};

	mutex_lock(&st->buf_lock);
	st->tx[0] = LIS3L02DQ_READ_REG(lower_reg_address);
	st->tx[1] = 0;
	st->tx[2] = LIS3L02DQ_READ_REG(lower_reg_address + 1);
	st->tx[3] = 0;

	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 when reading 16 bit register");
		goto error_ret;
	}
	tempval = (s16)(st->rx[1]) | ((s16)(st->rx[3]) << 8);

	*val = tempval;
error_ret:
	mutex_unlock(&st->buf_lock);
	return ret;
}

enum lis3l02dq_rm_ind {
	LIS3L02DQ_ACCEL,
	LIS3L02DQ_GAIN,
	LIS3L02DQ_BIAS,
};

static u8 lis3l02dq_axis_map[3][3] = {
	[LIS3L02DQ_ACCEL] = { LIS3L02DQ_REG_OUT_X_L_ADDR,
			      LIS3L02DQ_REG_OUT_Y_L_ADDR,
			      LIS3L02DQ_REG_OUT_Z_L_ADDR },
	[LIS3L02DQ_GAIN] = { LIS3L02DQ_REG_GAIN_X_ADDR,
			     LIS3L02DQ_REG_GAIN_Y_ADDR,
			     LIS3L02DQ_REG_GAIN_Z_ADDR },
	[LIS3L02DQ_BIAS] = { LIS3L02DQ_REG_OFFSET_X_ADDR,
			     LIS3L02DQ_REG_OFFSET_Y_ADDR,
			     LIS3L02DQ_REG_OFFSET_Z_ADDR }
};

static int lis3l02dq_read_thresh(struct iio_dev *indio_dev,
				 int e,
				 int *val)
{
	return lis3l02dq_read_reg_s16(indio_dev, LIS3L02DQ_REG_THS_L_ADDR, val);
}

static int lis3l02dq_write_thresh(struct iio_dev *indio_dev,
				  int event_code,
				  int val)
{
	u16 value = val;
	return lis3l02dq_spi_write_reg_s16(indio_dev,
					   LIS3L02DQ_REG_THS_L_ADDR,
					   value);
}

static int lis3l02dq_read_raw(struct iio_dev *indio_dev,
			      struct iio_chan_spec const *chan,
			      int *val,
			      int *val2,
			      long mask)
{
	u8 utemp;
	s8 stemp;
	ssize_t ret = 0;
	u8 reg;

	switch (mask) {
	case 0:
		/* Take the iio_dev status lock */
		mutex_lock(&indio_dev->mlock);
		if (indio_dev->currentmode == INDIO_RING_TRIGGERED)
			ret = lis3l02dq_read_accel_from_ring(indio_dev->ring,
							     chan->scan_index,
							     val);
		else {
			reg = lis3l02dq_axis_map
				[LIS3L02DQ_ACCEL][chan->address];
			ret = lis3l02dq_read_reg_s16(indio_dev, reg, val);
		}
		mutex_unlock(&indio_dev->mlock);
		return IIO_VAL_INT;
	case (1 << IIO_CHAN_INFO_SCALE_SHARED):
		*val = 0;
		*val2 = 9580;
		return IIO_VAL_INT_PLUS_MICRO;
	case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
		reg = lis3l02dq_axis_map[LIS3L02DQ_GAIN][chan->address];
		ret = lis3l02dq_spi_read_reg_8(indio_dev, reg, &utemp);
		if (ret)
			goto error_ret;
		/* to match with what previous code does */
		*val = utemp;
		return IIO_VAL_INT;

	case (1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE):
		reg = lis3l02dq_axis_map[LIS3L02DQ_BIAS][chan->address];
		ret = lis3l02dq_spi_read_reg_8(indio_dev, reg, (u8 *)&stemp);
		/* to match with what previous code does */
		*val = stemp;
		return IIO_VAL_INT;
	}
error_ret:
	return ret;
}

static ssize_t lis3l02dq_read_frequency(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	int ret, len = 0;
	s8 t;
	ret = lis3l02dq_spi_read_reg_8(indio_dev,
				       LIS3L02DQ_REG_CTRL_1_ADDR,
				       (u8 *)&t);
	if (ret)
		return ret;
	t &= LIS3L02DQ_DEC_MASK;
	switch (t) {
	case LIS3L02DQ_REG_CTRL_1_DF_128:
		len = sprintf(buf, "280\n");
		break;
	case LIS3L02DQ_REG_CTRL_1_DF_64:
		len = sprintf(buf, "560\n");
		break;
	case LIS3L02DQ_REG_CTRL_1_DF_32:
		len = sprintf(buf, "1120\n");
		break;
	case LIS3L02DQ_REG_CTRL_1_DF_8:
		len = sprintf(buf, "4480\n");
		break;
	}
	return len;
}

static ssize_t lis3l02dq_write_frequency(struct device *dev,
					 struct device_attribute *attr,
					 const char *buf,
					 size_t len)
{
	struct iio_dev *indio_dev = dev_get_drvdata(dev);
	long val;
	int ret;
	u8 t;

	ret = strict_strtol(buf, 10, &val);
	if (ret)
		return ret;

	mutex_lock(&indio_dev->mlock);
	ret = lis3l02dq_spi_read_reg_8(indio_dev,
				       LIS3L02DQ_REG_CTRL_1_ADDR,
				       &t);
	if (ret)
		goto error_ret_mutex;
	/* Wipe the bits clean */
	t &= ~LIS3L02DQ_DEC_MASK;
	switch (val) {
	case 280:
		t |= LIS3L02DQ_REG_CTRL_1_DF_128;
		break;
	case 560:
		t |= LIS3L02DQ_REG_CTRL_1_DF_64;
		break;
	case 1120:
		t |= LIS3L02DQ_REG_CTRL_1_DF_32;
		break;
	case 4480:
		t |= LIS3L02DQ_REG_CTRL_1_DF_8;
		break;
	default:
		ret = -EINVAL;
		goto error_ret_mutex;
	}

	ret = lis3l02dq_spi_write_reg_8(indio_dev,
					LIS3L02DQ_REG_CTRL_1_ADDR,
					&t);

error_ret_mutex:
	mutex_unlock(&indio_dev->mlock);

	return ret ? ret : len;
}

static int lis3l02dq_initial_setup(struct lis3l02dq_state *st)
{
	int ret;
	u8 val, valtest;

	st->us->mode = SPI_MODE_3;

	spi_setup(st->us);

	val = LIS3L02DQ_DEFAULT_CTRL1;
	/* Write suitable defaults to ctrl1 */
	ret = lis3l02dq_spi_write_reg_8(st->help.indio_dev,
					LIS3L02DQ_REG_CTRL_1_ADDR,
					&val);
	if (ret) {
		dev_err(&st->us->dev, "problem with setup control register 1");
		goto err_ret;
	}
	/* Repeat as sometimes doesn't work first time?*/
	ret = lis3l02dq_spi_write_reg_8(st->help.indio_dev,
					LIS3L02DQ_REG_CTRL_1_ADDR,
					&val);
	if (ret) {
		dev_err(&st->us->dev, "problem with setup control register 1");
		goto err_ret;
	}

	/* Read back to check this has worked acts as loose test of correct
	 * chip */
	ret = lis3l02dq_spi_read_reg_8(st->help.indio_dev,
				       LIS3L02DQ_REG_CTRL_1_ADDR,
				       &valtest);
	if (ret || (valtest != val)) {
		dev_err(&st->help.indio_dev->dev,
			"device not playing ball %d %d\n", valtest, val);
		ret = -EINVAL;
		goto err_ret;
	}

	val = LIS3L02DQ_DEFAULT_CTRL2;
	ret = lis3l02dq_spi_write_reg_8(st->help.indio_dev,
					LIS3L02DQ_REG_CTRL_2_ADDR,
					&val);
	if (ret) {
		dev_err(&st->us->dev, "problem with setup control register 2");
		goto err_ret;
	}

	val = LIS3L02DQ_REG_WAKE_UP_CFG_LATCH_SRC;
	ret = lis3l02dq_spi_write_reg_8(st->help.indio_dev,
					LIS3L02DQ_REG_WAKE_UP_CFG_ADDR,
					&val);
	if (ret)
		dev_err(&st->us->dev, "problem with interrupt cfg register");
err_ret:

	return ret;
}

static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
			      lis3l02dq_read_frequency,
			      lis3l02dq_write_frequency);

static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("280 560 1120 4480");

static int lis3l02dq_thresh_handler_th(struct iio_dev *indio_dev,
				       int index,
				       s64 timestamp,
				       int no_test)
{
	struct iio_sw_ring_helper_state *h
		= iio_dev_get_devdata(indio_dev);
	struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);

	/* Stash the timestamp somewhere convenient for the bh */
	st->thresh_timestamp = timestamp;
	schedule_work(&st->work_thresh);

	return 0;
}

/* A shared handler for a number of threshold types */
IIO_EVENT_SH(threshold, &lis3l02dq_thresh_handler_th);


#define LIS3L02DQ_INFO_MASK				\
	((1 << IIO_CHAN_INFO_SCALE_SHARED) |		\
	 (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |	\
	 (1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE))

#define LIS3L02DQ_EVENT_MASK					\
	(IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING) |	\
	 IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_FALLING))

static struct iio_chan_spec lis3l02dq_channels[] = {
	IIO_CHAN(IIO_ACCEL, 1, 0, 0, NULL, 0, IIO_MOD_X, LIS3L02DQ_INFO_MASK,
		 0, 0, IIO_ST('s', 12, 16, 0),
		 LIS3L02DQ_EVENT_MASK, &iio_event_threshold),
	IIO_CHAN(IIO_ACCEL, 1, 0, 0, NULL, 0, IIO_MOD_Y, LIS3L02DQ_INFO_MASK,
		 1, 1, IIO_ST('s', 12, 16, 0),
		 LIS3L02DQ_EVENT_MASK, &iio_event_threshold),
	IIO_CHAN(IIO_ACCEL, 1, 0, 0, NULL, 0, IIO_MOD_Z, LIS3L02DQ_INFO_MASK,
		 2, 2, IIO_ST('s', 12, 16, 0),
		 LIS3L02DQ_EVENT_MASK, &iio_event_threshold),
	IIO_CHAN_SOFT_TIMESTAMP(3)
};


static ssize_t lis3l02dq_read_event_config(struct iio_dev *indio_dev,
					   int event_code)
{

	u8 val;
	int ret;
	u8 mask = (1 << (IIO_EVENT_CODE_EXTRACT_MODIFIER(event_code)*2 +
			 (IIO_EVENT_CODE_EXTRACT_DIR(event_code) ==
			  IIO_EV_DIR_RISING)));
	ret = lis3l02dq_spi_read_reg_8(indio_dev,
				       LIS3L02DQ_REG_WAKE_UP_CFG_ADDR,
				       &val);
	if (ret < 0)
		return ret;

	return !!(val & mask);
}

static int lis3l02dq_write_event_config(struct iio_dev *indio_dev,
					int event_code,
					struct iio_event_handler_list *list_el,
					int state)
{
	int ret = 0;
	u8 val, control;
	u8 currentlyset;
	bool changed = false;
	u8 mask = (1 << (IIO_EVENT_CODE_EXTRACT_MODIFIER(event_code)*2 +
			 (IIO_EVENT_CODE_EXTRACT_DIR(event_code) ==
			  IIO_EV_DIR_RISING)));

	mutex_lock(&indio_dev->mlock);
	/* read current control */
	ret = lis3l02dq_spi_read_reg_8(indio_dev,
				       LIS3L02DQ_REG_CTRL_2_ADDR,
				       &control);
	if (ret)
		goto error_ret;
	ret = lis3l02dq_spi_read_reg_8(indio_dev,
				       LIS3L02DQ_REG_WAKE_UP_CFG_ADDR,
				       &val);
	if (ret < 0)
		goto error_ret;
	currentlyset = val & mask;

	if (!currentlyset && state) {
		changed = true;
		val |= mask;
		iio_add_event_to_list(list_el,
				      &indio_dev->interrupts[0]->ev_list);

	} else if (currentlyset && !state) {
		changed = true;
		val &= ~mask;
		iio_remove_event_from_list(list_el,
					   &indio_dev->interrupts[0]->ev_list);
	}
	if (changed) {
		ret = lis3l02dq_spi_write_reg_8(indio_dev,
						LIS3L02DQ_REG_WAKE_UP_CFG_ADDR,
						&val);
		if (ret)
			goto error_ret;
		control = list_el->refcount ?
			(control | LIS3L02DQ_REG_CTRL_2_ENABLE_INTERRUPT) :
			(control & ~LIS3L02DQ_REG_CTRL_2_ENABLE_INTERRUPT);
		ret = lis3l02dq_spi_write_reg_8(indio_dev,
					       LIS3L02DQ_REG_CTRL_2_ADDR,
					       &control);
	}

error_ret:
	mutex_unlock(&indio_dev->mlock);
	return ret;
}

/* Unforunately it appears the interrupt won't clear unless you read from the
 * src register.
 */
static void lis3l02dq_thresh_handler_bh_no_check(struct work_struct *work_s)
{
	struct lis3l02dq_state *st
		= container_of(work_s,
			       struct lis3l02dq_state, work_thresh);
	u8 t;

	lis3l02dq_spi_read_reg_8(st->help.indio_dev,
				 LIS3L02DQ_REG_WAKE_UP_SRC_ADDR,
				 &t);

	if (t & LIS3L02DQ_REG_WAKE_UP_SRC_INTERRUPT_Z_HIGH)
		iio_push_event(st->help.indio_dev, 0,
			       IIO_MOD_EVENT_CODE(IIO_EV_CLASS_ACCEL,
						  0,
						  IIO_EV_MOD_Z,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_RISING),
			       st->thresh_timestamp);

	if (t & LIS3L02DQ_REG_WAKE_UP_SRC_INTERRUPT_Z_LOW)
		iio_push_event(st->help.indio_dev, 0,
			       IIO_MOD_EVENT_CODE(IIO_EV_CLASS_ACCEL,
						  0,
						  IIO_EV_MOD_Z,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_FALLING),
			       st->thresh_timestamp);

	if (t & LIS3L02DQ_REG_WAKE_UP_SRC_INTERRUPT_Y_HIGH)
		iio_push_event(st->help.indio_dev, 0,
			       IIO_MOD_EVENT_CODE(IIO_EV_CLASS_ACCEL,
						  0,
						  IIO_EV_MOD_Y,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_RISING),
			       st->thresh_timestamp);

	if (t & LIS3L02DQ_REG_WAKE_UP_SRC_INTERRUPT_Y_LOW)
		iio_push_event(st->help.indio_dev, 0,
			       IIO_MOD_EVENT_CODE(IIO_EV_CLASS_ACCEL,
						  0,
						  IIO_EV_MOD_Y,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_FALLING),
			       st->thresh_timestamp);

	if (t & LIS3L02DQ_REG_WAKE_UP_SRC_INTERRUPT_X_HIGH)
		iio_push_event(st->help.indio_dev, 0,
			       IIO_MOD_EVENT_CODE(IIO_EV_CLASS_ACCEL,
						  0,
						  IIO_EV_MOD_X,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_RISING),
			       st->thresh_timestamp);

	if (t & LIS3L02DQ_REG_WAKE_UP_SRC_INTERRUPT_X_LOW)
		iio_push_event(st->help.indio_dev, 0,
			       IIO_MOD_EVENT_CODE(IIO_EV_CLASS_ACCEL,
						  0,
						  IIO_EV_MOD_X,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_FALLING),
			       st->thresh_timestamp);
	/* reenable the irq */
	enable_irq(st->us->irq);
	/* Ack and allow for new interrupts */
	lis3l02dq_spi_read_reg_8(st->help.indio_dev,
				 LIS3L02DQ_REG_WAKE_UP_ACK_ADDR,
				 &t);

	return;
}

static IIO_CONST_ATTR_NAME("lis3l02dq");

static struct attribute *lis3l02dq_attributes[] = {
	&iio_dev_attr_sampling_frequency.dev_attr.attr,
	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
	&iio_const_attr_name.dev_attr.attr,
	NULL
};

static const struct attribute_group lis3l02dq_attribute_group = {
	.attrs = lis3l02dq_attributes,
};

static int __devinit lis3l02dq_probe(struct spi_device *spi)
{
	int ret, regdone = 0;
	struct lis3l02dq_state *st = kzalloc(sizeof *st, GFP_KERNEL);
	if (!st) {
		ret =  -ENOMEM;
		goto error_ret;
	}
	INIT_WORK(&st->work_thresh, lis3l02dq_thresh_handler_bh_no_check);
	/* this is only used tor removal purposes */
	spi_set_drvdata(spi, st);

	/* Allocate the comms buffers */
	st->rx = kzalloc(sizeof(*st->rx)*LIS3L02DQ_MAX_RX, GFP_KERNEL);
	if (st->rx == NULL) {
		ret = -ENOMEM;
		goto error_free_st;
	}
	st->tx = kzalloc(sizeof(*st->tx)*LIS3L02DQ_MAX_TX, GFP_KERNEL);
	if (st->tx == NULL) {
		ret = -ENOMEM;
		goto error_free_rx;
	}
	st->us = spi;
	mutex_init(&st->buf_lock);
	/* setup the industrialio driver allocated elements */
	st->help.indio_dev = iio_allocate_device(0);
	if (st->help.indio_dev == NULL) {
		ret = -ENOMEM;
		goto error_free_tx;
	}

	st->help.indio_dev->dev.parent = &spi->dev;
	st->help.indio_dev->num_interrupt_lines = 1;
	st->help.indio_dev->channels = lis3l02dq_channels;
	st->help.indio_dev->num_channels = ARRAY_SIZE(lis3l02dq_channels);
	st->help.indio_dev->read_raw = &lis3l02dq_read_raw;
	st->help.indio_dev->read_event_value = &lis3l02dq_read_thresh;
	st->help.indio_dev->write_event_value = &lis3l02dq_write_thresh;
	st->help.indio_dev->write_event_config = &lis3l02dq_write_event_config;
	st->help.indio_dev->read_event_config = &lis3l02dq_read_event_config;
	st->help.indio_dev->attrs = &lis3l02dq_attribute_group;
	st->help.indio_dev->dev_data = (void *)(&st->help);
	st->help.indio_dev->driver_module = THIS_MODULE;
	st->help.indio_dev->modes = INDIO_DIRECT_MODE;

	ret = lis3l02dq_configure_ring(st->help.indio_dev);
	if (ret)
		goto error_free_dev;

	ret = iio_device_register(st->help.indio_dev);
	if (ret)
		goto error_unreg_ring_funcs;
	regdone = 1;

	ret = iio_ring_buffer_register_ex(st->help.indio_dev->ring, 0,
					  lis3l02dq_channels,
					  ARRAY_SIZE(lis3l02dq_channels));
	if (ret) {
		printk(KERN_ERR "failed to initialize the ring\n");
		goto error_unreg_ring_funcs;
	}

	if (spi->irq && gpio_is_valid(irq_to_gpio(spi->irq)) > 0) {
		st->inter = 0;
		ret = iio_register_interrupt_line(spi->irq,
						  st->help.indio_dev,
						  0,
						  IRQF_TRIGGER_RISING,
						  "lis3l02dq");
		if (ret)
			goto error_uninitialize_ring;

		ret = lis3l02dq_probe_trigger(st->help.indio_dev);
		if (ret)
			goto error_unregister_line;
	}

	/* Get the device into a sane initial state */
	ret = lis3l02dq_initial_setup(st);
	if (ret)
		goto error_remove_trigger;
	return 0;

error_remove_trigger:
	if (st->help.indio_dev->modes & INDIO_RING_TRIGGERED)
		lis3l02dq_remove_trigger(st->help.indio_dev);
error_unregister_line:
	if (st->help.indio_dev->modes & INDIO_RING_TRIGGERED)
		iio_unregister_interrupt_line(st->help.indio_dev, 0);
error_uninitialize_ring:
	iio_ring_buffer_unregister(st->help.indio_dev->ring);
error_unreg_ring_funcs:
	lis3l02dq_unconfigure_ring(st->help.indio_dev);
error_free_dev:
	if (regdone)
		iio_device_unregister(st->help.indio_dev);
	else
		iio_free_device(st->help.indio_dev);
error_free_tx:
	kfree(st->tx);
error_free_rx:
	kfree(st->rx);
error_free_st:
	kfree(st);
error_ret:
	return ret;
}

/* Power down the device */
static int lis3l02dq_stop_device(struct iio_dev *indio_dev)
{
	int ret;
	struct iio_sw_ring_helper_state *h
		= iio_dev_get_devdata(indio_dev);
	struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);
	u8 val = 0;

	mutex_lock(&indio_dev->mlock);
	ret = lis3l02dq_spi_write_reg_8(indio_dev,
					LIS3L02DQ_REG_CTRL_1_ADDR,
					&val);
	if (ret) {
		dev_err(&st->us->dev, "problem with turning device off: ctrl1");
		goto err_ret;
	}

	ret = lis3l02dq_spi_write_reg_8(indio_dev,
					LIS3L02DQ_REG_CTRL_2_ADDR,
					&val);
	if (ret)
		dev_err(&st->us->dev, "problem with turning device off: ctrl2");
err_ret:
	mutex_unlock(&indio_dev->mlock);
	return ret;
}

/* fixme, confirm ordering in this function */
static int lis3l02dq_remove(struct spi_device *spi)
{
	int ret;
	struct lis3l02dq_state *st = spi_get_drvdata(spi);
	struct iio_dev *indio_dev = st->help.indio_dev;

	ret = lis3l02dq_stop_device(indio_dev);
	if (ret)
		goto err_ret;

	flush_scheduled_work();

	lis3l02dq_remove_trigger(indio_dev);
	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);
	lis3l02dq_unconfigure_ring(indio_dev);
	iio_device_unregister(indio_dev);
	kfree(st->tx);
	kfree(st->rx);
	kfree(st);

	return 0;

err_ret:
	return ret;
}

static struct spi_driver lis3l02dq_driver = {
	.driver = {
		.name = "lis3l02dq",
		.owner = THIS_MODULE,
	},
	.probe = lis3l02dq_probe,
	.remove = __devexit_p(lis3l02dq_remove),
};

static __init int lis3l02dq_init(void)
{
	return spi_register_driver(&lis3l02dq_driver);
}
module_init(lis3l02dq_init);

static __exit void lis3l02dq_exit(void)
{
	spi_unregister_driver(&lis3l02dq_driver);
}
module_exit(lis3l02dq_exit);

MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
MODULE_DESCRIPTION("ST LIS3L02DQ Accelerometer SPI driver");
MODULE_LICENSE("GPL v2");