staging: iio: adis16350 and similar IMU driver

This version has the right part number in the commit message.
Whilst technically the part I listed last time is also supported
by the driver, the commit message might have caused confusion.

Another driver from Barry at Analog.  Again, I've lifted
if from the blackfin tree and done the usual sparse
and checkpatch fixes + the abi changes.  I actually
have one of these, so am particularly pleased to see
it supported!
Signed-off-by: NBarry Song <Barry.Song@analog.com>
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/imu/Kconfig

@@ -13,6 +13,15 @@ config ADIS16300
 	  Say yes here to build support for Analog Devices adis16300 four degrees
 	  of freedom inertial sensor.
 
+config ADIS16350
+	tristate "Analog Devices ADIS16350/54/55/60/62/64/65 IMU SPI driver"
+	depends on SPI
+	select IIO_TRIGGER if IIO_RING_BUFFER
+	select IIO_SW_RING if IIO_RING_BUFFER
+	help
+	  Say yes here to build support for Analog Devices adis16350/54/55/60/62/64/65
+	  high precision tri-axis inertial sensor.
+
 config ADIS16400
 	tristate "Analog Devices ADIS16400/5 IMU SPI driver"
  	depends on SPI

drivers/staging/iio/imu/Makefile

@@ -5,6 +5,10 @@ adis16300-y             := adis16300_core.o
 adis16300-$(CONFIG_IIO_RING_BUFFER) += adis16300_ring.o adis16300_trigger.o
 obj-$(CONFIG_ADIS16300) += adis16300.o
 
+adis16350-y             := adis16350_core.o
+adis16350-$(CONFIG_IIO_RING_BUFFER) += adis16350_ring.o adis16350_trigger.o
+obj-$(CONFIG_ADIS16350) += adis16350.o
+
 adis16400-y             := adis16400_core.o
 adis16400-$(CONFIG_IIO_RING_BUFFER) += adis16400_ring.o adis16400_trigger.o
 obj-$(CONFIG_ADIS16400) += adis16400.o
\ No newline at end of file

drivers/staging/iio/imu/adis16350.h

+#ifndef SPI_ADIS16350_H_
+#define SPI_ADIS16350_H_
+
+#define ADIS16350_STARTUP_DELAY	220 /* ms */
+
+#define ADIS16350_READ_REG(a)    a
+#define ADIS16350_WRITE_REG(a) ((a) | 0x80)
+
+#define ADIS16350_FLASH_CNT  0x00 /* Flash memory write count */
+#define ADIS16350_SUPPLY_OUT 0x02 /* Power supply measurement */
+#define ADIS16350_XGYRO_OUT 0x04 /* X-axis gyroscope output */
+#define ADIS16350_YGYRO_OUT 0x06 /* Y-axis gyroscope output */
+#define ADIS16350_ZGYRO_OUT 0x08 /* Z-axis gyroscope output */
+#define ADIS16350_XACCL_OUT 0x0A /* X-axis accelerometer output */
+#define ADIS16350_YACCL_OUT 0x0C /* Y-axis accelerometer output */
+#define ADIS16350_ZACCL_OUT 0x0E /* Z-axis accelerometer output */
+#define ADIS16350_XTEMP_OUT 0x10 /* X-axis gyroscope temperature measurement */
+#define ADIS16350_YTEMP_OUT 0x12 /* Y-axis gyroscope temperature measurement */
+#define ADIS16350_ZTEMP_OUT 0x14 /* Z-axis gyroscope temperature measurement */
+#define ADIS16350_AUX_ADC   0x16 /* Auxiliary ADC measurement */
+
+/* Calibration parameters */
+#define ADIS16350_XGYRO_OFF 0x1A /* X-axis gyroscope bias offset factor */
+#define ADIS16350_YGYRO_OFF 0x1C /* Y-axis gyroscope bias offset factor */
+#define ADIS16350_ZGYRO_OFF 0x1E /* Z-axis gyroscope bias offset factor */
+#define ADIS16350_XACCL_OFF 0x20 /* X-axis acceleration bias offset factor */
+#define ADIS16350_YACCL_OFF 0x22 /* Y-axis acceleration bias offset factor */
+#define ADIS16350_ZACCL_OFF 0x24 /* Z-axis acceleration bias offset factor */
+
+#define ADIS16350_GPIO_CTRL 0x32 /* Auxiliary digital input/output control */
+#define ADIS16350_MSC_CTRL  0x34 /* Miscellaneous control */
+#define ADIS16350_SMPL_PRD  0x36 /* Internal sample period (rate) control */
+#define ADIS16350_SENS_AVG  0x38 /* Dynamic range and digital filter control */
+#define ADIS16350_SLP_CNT   0x3A /* Sleep mode control */
+#define ADIS16350_DIAG_STAT 0x3C /* System status */
+
+/* Alarm functions */
+#define ADIS16350_GLOB_CMD  0x3E /* System command */
+#define ADIS16350_ALM_MAG1  0x26 /* Alarm 1 amplitude threshold */
+#define ADIS16350_ALM_MAG2  0x28 /* Alarm 2 amplitude threshold */
+#define ADIS16350_ALM_SMPL1 0x2A /* Alarm 1 sample size */
+#define ADIS16350_ALM_SMPL2 0x2C /* Alarm 2 sample size */
+#define ADIS16350_ALM_CTRL  0x2E /* Alarm control */
+#define ADIS16350_AUX_DAC   0x30 /* Auxiliary DAC data */
+
+#define ADIS16350_ERROR_ACTIVE			(1<<14)
+#define ADIS16350_NEW_DATA			(1<<15)
+
+/* MSC_CTRL */
+#define ADIS16350_MSC_CTRL_MEM_TEST		(1<<11)
+#define ADIS16350_MSC_CTRL_INT_SELF_TEST	(1<<10)
+#define ADIS16350_MSC_CTRL_NEG_SELF_TEST	(1<<9)
+#define ADIS16350_MSC_CTRL_POS_SELF_TEST	(1<<8)
+#define ADIS16350_MSC_CTRL_GYRO_BIAS		(1<<7)
+#define ADIS16350_MSC_CTRL_ACCL_ALIGN		(1<<6)
+#define ADIS16350_MSC_CTRL_DATA_RDY_EN		(1<<2)
+#define ADIS16350_MSC_CTRL_DATA_RDY_POL_HIGH	(1<<1)
+#define ADIS16350_MSC_CTRL_DATA_RDY_DIO2	(1<<0)
+
+/* SMPL_PRD */
+#define ADIS16350_SMPL_PRD_TIME_BASE	(1<<7)
+#define ADIS16350_SMPL_PRD_DIV_MASK	0x7F
+
+/* DIAG_STAT */
+#define ADIS16350_DIAG_STAT_ZACCL_FAIL	(1<<15)
+#define ADIS16350_DIAG_STAT_YACCL_FAIL	(1<<14)
+#define ADIS16350_DIAG_STAT_XACCL_FAIL	(1<<13)
+#define ADIS16350_DIAG_STAT_XGYRO_FAIL	(1<<12)
+#define ADIS16350_DIAG_STAT_YGYRO_FAIL	(1<<11)
+#define ADIS16350_DIAG_STAT_ZGYRO_FAIL	(1<<10)
+#define ADIS16350_DIAG_STAT_ALARM2	(1<<9)
+#define ADIS16350_DIAG_STAT_ALARM1	(1<<8)
+#define ADIS16350_DIAG_STAT_FLASH_CHK	(1<<6)
+#define ADIS16350_DIAG_STAT_SELF_TEST	(1<<5)
+#define ADIS16350_DIAG_STAT_OVERFLOW	(1<<4)
+#define ADIS16350_DIAG_STAT_SPI_FAIL	(1<<3)
+#define ADIS16350_DIAG_STAT_FLASH_UPT	(1<<2)
+#define ADIS16350_DIAG_STAT_POWER_HIGH	(1<<1)
+#define ADIS16350_DIAG_STAT_POWER_LOW	(1<<0)
+
+/* GLOB_CMD */
+#define ADIS16350_GLOB_CMD_SW_RESET	(1<<7)
+#define ADIS16350_GLOB_CMD_P_AUTO_NULL	(1<<4)
+#define ADIS16350_GLOB_CMD_FLASH_UPD	(1<<3)
+#define ADIS16350_GLOB_CMD_DAC_LATCH	(1<<2)
+#define ADIS16350_GLOB_CMD_FAC_CALIB	(1<<1)
+#define ADIS16350_GLOB_CMD_AUTO_NULL	(1<<0)
+
+/* SLP_CNT */
+#define ADIS16350_SLP_CNT_POWER_OFF	(1<<8)
+
+#define ADIS16350_MAX_TX 24
+#define ADIS16350_MAX_RX 24
+
+#define ADIS16350_SPI_SLOW	(u32)(300 * 1000)
+#define ADIS16350_SPI_BURST	(u32)(1000 * 1000)
+#define ADIS16350_SPI_FAST	(u32)(2000 * 1000)
+
+/**
+ * struct adis16350_state - device instance specific data
+ * @us:			actual spi_device
+ * @work_trigger_to_ring: bh for triggered event handling
+ * @work_cont_thresh: CLEAN
+ * @inter:		used to check if new interrupt has been triggered
+ * @last_timestamp:	passing timestamp from th to bh of interrupt handler
+ * @indio_dev:		industrial I/O device structure
+ * @trig:		data ready trigger registered with iio
+ * @tx:			transmit buffer
+ * @rx:			recieve buffer
+ * @buf_lock:		mutex to protect tx and rx
+ **/
+struct adis16350_state {
+	struct spi_device		*us;
+	struct work_struct		work_trigger_to_ring;
+	struct iio_work_cont		work_cont_data_rdy;
+	s64				last_timestamp;
+	struct iio_dev			*indio_dev;
+	struct iio_trigger		*trig;
+	u8				*tx;
+	u8				*rx;
+	struct mutex			buf_lock;
+};
+
+int adis16350_set_irq(struct device *dev, bool enable);
+
+#ifdef CONFIG_IIO_RING_BUFFER
+
+enum adis16350_scan {
+	ADIS16350_SCAN_SUPPLY,
+	ADIS16350_SCAN_GYRO_X,
+	ADIS16350_SCAN_GYRO_Y,
+	ADIS16350_SCAN_GYRO_Z,
+	ADIS16350_SCAN_ACC_X,
+	ADIS16350_SCAN_ACC_Y,
+	ADIS16350_SCAN_ACC_Z,
+	ADIS16350_SCAN_TEMP_X,
+	ADIS16350_SCAN_TEMP_Y,
+	ADIS16350_SCAN_TEMP_Z,
+	ADIS16350_SCAN_ADC_0
+};
+
+void adis16350_remove_trigger(struct iio_dev *indio_dev);
+int adis16350_probe_trigger(struct iio_dev *indio_dev);
+
+ssize_t adis16350_read_data_from_ring(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf);
+
+
+int adis16350_configure_ring(struct iio_dev *indio_dev);
+void adis16350_unconfigure_ring(struct iio_dev *indio_dev);
+
+int adis16350_initialize_ring(struct iio_ring_buffer *ring);
+void adis16350_uninitialize_ring(struct iio_ring_buffer *ring);
+#else /* CONFIG_IIO_RING_BUFFER */
+
+static inline void adis16350_remove_trigger(struct iio_dev *indio_dev)
+{
+}
+
+static inline int adis16350_probe_trigger(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline ssize_t
+adis16350_read_data_from_ring(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	return 0;
+}
+
+static int adis16350_configure_ring(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline void adis16350_unconfigure_ring(struct iio_dev *indio_dev)
+{
+}
+
+static inline int adis16350_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return 0;
+}
+
+static inline void adis16350_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+}
+
+#endif /* CONFIG_IIO_RING_BUFFER */
+#endif /* SPI_ADIS16350_H_ */

drivers/staging/iio/imu/adis16350_core.c

+/*
+ * ADIS16350/54/55/60/62/64/65 high precision tri-axis inertial sensor
+ *
+ * Copyright 2010 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/spi/spi.h>
+
+#include <linux/sysfs.h>
+#include <linux/list.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../accel/accel.h"
+#include "../adc/adc.h"
+#include "../gyro/gyro.h"
+
+#include "adis16350.h"
+
+#define DRIVER_NAME		"adis16350"
+
+static int adis16350_check_status(struct device *dev);
+
+/**
+ * adis16350_spi_write_reg_8() - write single byte to a register
+ * @dev: device associated with child of actual device (iio_dev or iio_trig)
+ * @reg_address: the address of the register to be written
+ * @val: the value to write
+ **/
+static int adis16350_spi_write_reg_8(struct device *dev,
+		u8 reg_address,
+		u8 val)
+{
+	int ret;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct adis16350_state *st = iio_dev_get_devdata(indio_dev);
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADIS16350_WRITE_REG(reg_address);
+	st->tx[1] = val;
+
+	ret = spi_write(st->us, st->tx, 2);
+	mutex_unlock(&st->buf_lock);
+
+	return ret;
+}
+
+/**
+ * adis16350_spi_write_reg_16() - write 2 bytes to a pair of registers
+ * @dev: device associated with child of actual device (iio_dev or iio_trig)
+ * @reg_address: the address of the lower of the two registers. Second register
+ *               is assumed to have address one greater.
+ * @val: value to be written
+ **/
+static int adis16350_spi_write_reg_16(struct device *dev,
+		u8 lower_reg_address,
+		u16 value)
+{
+	int ret;
+	struct spi_message msg;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct adis16350_state *st = iio_dev_get_devdata(indio_dev);
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = st->tx,
+			.bits_per_word = 8,
+			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = 25,
+		}, {
+			.tx_buf = st->tx + 2,
+			.bits_per_word = 8,
+			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = 25,
+		},
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADIS16350_WRITE_REG(lower_reg_address);
+	st->tx[1] = value & 0xFF;
+	st->tx[2] = ADIS16350_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;
+}
+
+/**
+ * adis16350_spi_read_reg_16() - read 2 bytes from a 16-bit register
+ * @dev: device associated with child of actual device (iio_dev or iio_trig)
+ * @reg_address: the address of the lower of the two registers. Second register
+ *               is assumed to have address one greater.
+ * @val: somewhere to pass back the value read
+ **/
+static int adis16350_spi_read_reg_16(struct device *dev,
+		u8 lower_reg_address,
+		u16 *val)
+{
+	struct spi_message msg;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct adis16350_state *st = iio_dev_get_devdata(indio_dev);
+	int ret;
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = st->tx,
+			.bits_per_word = 8,
+			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = 25,
+		}, {
+			.rx_buf = st->rx,
+			.bits_per_word = 8,
+			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = 25,
+		},
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADIS16350_READ_REG(lower_reg_address);
+	st->tx[1] = 0;
+	st->tx[2] = 0;
+	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 0x%02X",
+			lower_reg_address);
+		goto error_ret;
+	}
+	*val = (st->rx[0] << 8) | st->rx[1];
+
+error_ret:
+	mutex_unlock(&st->buf_lock);
+	return ret;
+}
+
+
+static ssize_t adis16350_spi_read_signed(struct device *dev,
+		struct device_attribute *attr,
+		char *buf,
+		unsigned bits)
+{
+	int ret;
+	s16 val = 0;
+	unsigned shift = 16 - bits;
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	ret = adis16350_spi_read_reg_16(dev, this_attr->address, (u16 *)&val);
+	if (ret)
+		return ret;
+
+	if (val & ADIS16350_ERROR_ACTIVE)
+		adis16350_check_status(dev);
+	val = ((s16)(val << shift) >> shift);
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t adis16350_read_12bit_unsigned(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	int ret;
+	u16 val = 0;
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	ret = adis16350_spi_read_reg_16(dev, this_attr->address, &val);
+	if (ret)
+		return ret;
+
+	if (val & ADIS16350_ERROR_ACTIVE)
+		adis16350_check_status(dev);
+
+	return sprintf(buf, "%u\n", val & 0x0FFF);
+}
+
+static ssize_t adis16350_read_14bit_signed(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	ssize_t ret;
+
+	/* Take the iio_dev status lock */
+	mutex_lock(&indio_dev->mlock);
+	ret =  adis16350_spi_read_signed(dev, attr, buf, 14);
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static ssize_t adis16350_read_12bit_signed(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	ssize_t ret;
+
+	/* Take the iio_dev status lock */
+	mutex_lock(&indio_dev->mlock);
+	ret =  adis16350_spi_read_signed(dev, attr, buf, 12);
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static ssize_t adis16350_write_16bit(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int ret;
+	long val;
+
+	ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		goto error_ret;
+	ret = adis16350_spi_write_reg_16(dev, this_attr->address, val);
+
+error_ret:
+	return ret ? ret : len;
+}
+
+static ssize_t adis16350_read_frequency(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	int ret, len = 0;
+	u16 t;
+	int sps;
+	ret = adis16350_spi_read_reg_16(dev,
+			ADIS16350_SMPL_PRD,
+			&t);
+	if (ret)
+		return ret;
+	sps =  (t & ADIS16350_SMPL_PRD_TIME_BASE) ? 53 : 1638;
+	sps /= (t & ADIS16350_SMPL_PRD_DIV_MASK) + 1;
+	len = sprintf(buf, "%d SPS\n", sps);
+	return len;
+}
+
+static ssize_t adis16350_write_frequency(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct adis16350_state *st = iio_dev_get_devdata(indio_dev);
+	long val;
+	int ret;
+	u8 t;
+
+	ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&indio_dev->mlock);
+
+	t = (1638 / val);
+	if (t > 0)
+		t--;
+	t &= ADIS16350_SMPL_PRD_DIV_MASK;
+	if ((t & ADIS16350_SMPL_PRD_DIV_MASK) >= 0x0A)
+		st->us->max_speed_hz = ADIS16350_SPI_SLOW;
+	else
+		st->us->max_speed_hz = ADIS16350_SPI_FAST;
+
+	ret = adis16350_spi_write_reg_8(dev,
+			ADIS16350_SMPL_PRD,
+			t);
+
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret ? ret : len;
+}
+
+static int adis16350_reset(struct device *dev)
+{
+	int ret;
+	ret = adis16350_spi_write_reg_8(dev,
+			ADIS16350_GLOB_CMD,
+			ADIS16350_GLOB_CMD_SW_RESET);
+	if (ret)
+		dev_err(dev, "problem resetting device");
+
+	return ret;
+}
+
+static ssize_t adis16350_write_reset(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t len)
+{
+	if (len < 1)
+		return -1;
+	switch (buf[0]) {
+	case '1':
+	case 'y':
+	case 'Y':
+		return adis16350_reset(dev);
+	}
+	return -1;
+}
+
+int adis16350_set_irq(struct device *dev, bool enable)
+{
+	int ret;
+	u16 msc;
+	ret = adis16350_spi_read_reg_16(dev, ADIS16350_MSC_CTRL, &msc);
+	if (ret)
+		goto error_ret;
+
+	msc |= ADIS16350_MSC_CTRL_DATA_RDY_POL_HIGH;
+	msc &= ~ADIS16350_MSC_CTRL_DATA_RDY_DIO2;
+
+	if (enable)
+		msc |= ADIS16350_MSC_CTRL_DATA_RDY_EN;
+	else
+		msc &= ~ADIS16350_MSC_CTRL_DATA_RDY_EN;
+
+	ret = adis16350_spi_write_reg_16(dev, ADIS16350_MSC_CTRL, msc);
+	if (ret)
+		goto error_ret;
+
+error_ret:
+	return ret;
+}
+
+/* Power down the device */
+static int adis16350_stop_device(struct device *dev)
+{
+	int ret;
+	u16 val = ADIS16350_SLP_CNT_POWER_OFF;
+
+	ret = adis16350_spi_write_reg_16(dev, ADIS16350_SLP_CNT, val);
+	if (ret)
+		dev_err(dev, "problem with turning device off: SLP_CNT");
+
+	return ret;
+}
+
+static int adis16350_self_test(struct device *dev)
+{
+	int ret;
+	ret = adis16350_spi_write_reg_16(dev,
+			ADIS16350_MSC_CTRL,
+			ADIS16350_MSC_CTRL_MEM_TEST);
+	if (ret) {
+		dev_err(dev, "problem starting self test");
+		goto err_ret;
+	}
+
+	adis16350_check_status(dev);
+
+err_ret:
+	return ret;
+}
+
+static int adis16350_check_status(struct device *dev)
+{
+	u16 status;
+	int ret;
+
+	ret = adis16350_spi_read_reg_16(dev, ADIS16350_DIAG_STAT, &status);
+
+	if (ret < 0) {
+		dev_err(dev, "Reading status failed\n");
+		goto error_ret;
+	}
+	ret = status;
+	if (status & ADIS16350_DIAG_STAT_ZACCL_FAIL)
+		dev_err(dev, "Z-axis accelerometer self-test failure\n");
+	if (status & ADIS16350_DIAG_STAT_YACCL_FAIL)
+		dev_err(dev, "Y-axis accelerometer self-test failure\n");
+	if (status & ADIS16350_DIAG_STAT_XACCL_FAIL)
+		dev_err(dev, "X-axis accelerometer self-test failure\n");
+	if (status & ADIS16350_DIAG_STAT_XGYRO_FAIL)
+		dev_err(dev, "X-axis gyroscope self-test failure\n");
+	if (status & ADIS16350_DIAG_STAT_YGYRO_FAIL)
+		dev_err(dev, "Y-axis gyroscope self-test failure\n");
+	if (status & ADIS16350_DIAG_STAT_ZGYRO_FAIL)
+		dev_err(dev, "Z-axis gyroscope self-test failure\n");
+	if (status & ADIS16350_DIAG_STAT_ALARM2)
+		dev_err(dev, "Alarm 2 active\n");
+	if (status & ADIS16350_DIAG_STAT_ALARM1)
+		dev_err(dev, "Alarm 1 active\n");
+	if (status & ADIS16350_DIAG_STAT_FLASH_CHK)
+		dev_err(dev, "Flash checksum error\n");
+	if (status & ADIS16350_DIAG_STAT_SELF_TEST)
+		dev_err(dev, "Self test error\n");
+	if (status & ADIS16350_DIAG_STAT_OVERFLOW)
+		dev_err(dev, "Sensor overrange\n");
+	if (status & ADIS16350_DIAG_STAT_SPI_FAIL)
+		dev_err(dev, "SPI failure\n");
+	if (status & ADIS16350_DIAG_STAT_FLASH_UPT)
+		dev_err(dev, "Flash update failed\n");
+	if (status & ADIS16350_DIAG_STAT_POWER_HIGH)
+		dev_err(dev, "Power supply above 5.25V\n");
+	if (status & ADIS16350_DIAG_STAT_POWER_LOW)
+		dev_err(dev, "Power supply below 4.75V\n");
+
+error_ret:
+	return ret;
+}
+
+static int adis16350_initial_setup(struct adis16350_state *st)
+{
+	int ret;
+	u16 smp_prd;
+	struct device *dev = &st->indio_dev->dev;
+
+	/* use low spi speed for init */
+	st->us->max_speed_hz = ADIS16350_SPI_SLOW;
+	st->us->mode = SPI_MODE_3;
+	spi_setup(st->us);
+
+	/* Disable IRQ */
+	ret = adis16350_set_irq(dev, false);
+	if (ret) {
+		dev_err(dev, "disable irq failed");
+		goto err_ret;
+	}
+
+	/* Do self test */
+	ret = adis16350_self_test(dev);
+	if (ret) {
+		dev_err(dev, "self test failure");
+		goto err_ret;
+	}
+
+	/* Read status register to check the result */
+	ret = adis16350_check_status(dev);
+	if (ret) {
+		adis16350_reset(dev);
+		dev_err(dev, "device not playing ball -> reset");
+		msleep(ADIS16350_STARTUP_DELAY);
+		ret = adis16350_check_status(dev);
+		if (ret) {
+			dev_err(dev, "giving up");
+			goto err_ret;
+		}
+	}
+
+	printk(KERN_INFO DRIVER_NAME ": at CS%d (irq %d)\n",
+			st->us->chip_select, st->us->irq);
+
+	/* use high spi speed if possible */
+	ret = adis16350_spi_read_reg_16(dev, ADIS16350_SMPL_PRD, &smp_prd);
+	if (!ret && (smp_prd & ADIS16350_SMPL_PRD_DIV_MASK) < 0x0A) {
+		st->us->max_speed_hz = ADIS16350_SPI_SLOW;
+		spi_setup(st->us);
+	}
+
+err_ret:
+	return ret;
+}
+
+static IIO_DEV_ATTR_ACCEL_X_OFFSET(S_IWUSR | S_IRUGO,
+		adis16350_read_12bit_signed,
+		adis16350_write_16bit,
+		ADIS16350_XACCL_OFF);
+
+static IIO_DEV_ATTR_ACCEL_Y_OFFSET(S_IWUSR | S_IRUGO,
+		adis16350_read_12bit_signed,
+		adis16350_write_16bit,
+		ADIS16350_YACCL_OFF);
+
+static IIO_DEV_ATTR_ACCEL_Z_OFFSET(S_IWUSR | S_IRUGO,
+		adis16350_read_12bit_signed,
+		adis16350_write_16bit,
+		ADIS16350_ZACCL_OFF);
+
+static IIO_DEV_ATTR_IN_NAMED_RAW(supply, adis16350_read_12bit_unsigned,
+		ADIS16350_SUPPLY_OUT);
+static IIO_CONST_ATTR(in_supply_scale, "0.002418");
+
+static IIO_DEV_ATTR_GYRO_X(adis16350_read_14bit_signed,
+		ADIS16350_XGYRO_OUT);
+static IIO_DEV_ATTR_GYRO_Y(adis16350_read_14bit_signed,
+		ADIS16350_YGYRO_OUT);
+static IIO_DEV_ATTR_GYRO_Z(adis16350_read_14bit_signed,
+		ADIS16350_ZGYRO_OUT);
+static IIO_CONST_ATTR(gyro_scale, "0.05");
+
+static IIO_DEV_ATTR_ACCEL_X(adis16350_read_14bit_signed,
+		ADIS16350_XACCL_OUT);
+static IIO_DEV_ATTR_ACCEL_Y(adis16350_read_14bit_signed,
+		ADIS16350_YACCL_OUT);
+static IIO_DEV_ATTR_ACCEL_Z(adis16350_read_14bit_signed,
+		ADIS16350_ZACCL_OUT);
+static IIO_CONST_ATTR(accel_scale, "0.00333");
+
+static IIO_DEVICE_ATTR(temp_x_raw, S_IRUGO, adis16350_read_12bit_signed,
+		NULL, ADIS16350_XTEMP_OUT);
+static IIO_DEVICE_ATTR(temp_y_raw, S_IRUGO, adis16350_read_12bit_signed,
+		NULL, ADIS16350_YTEMP_OUT);
+static IIO_DEVICE_ATTR(temp_z_raw, S_IRUGO, adis16350_read_12bit_signed,
+		NULL, ADIS16350_ZTEMP_OUT);
+static IIO_CONST_ATTR(temp_scale, "0.0005");
+
+static IIO_DEV_ATTR_IN_RAW(0, adis16350_read_12bit_unsigned,
+		ADIS16350_AUX_ADC);
+static IIO_CONST_ATTR(in0_scale, "0.000806");
+
+static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
+		adis16350_read_frequency,
+		adis16350_write_frequency);
+
+static IIO_DEVICE_ATTR(reset, S_IWUSR, NULL,
+		adis16350_write_reset, 0);
+
+static IIO_CONST_ATTR_AVAIL_SAMP_FREQ("409 546 819 1638");
+
+static IIO_CONST_ATTR(name, "adis16350");
+
+static struct attribute *adis16350_attributes[] = {
+	&iio_dev_attr_accel_x_offset.dev_attr.attr,
+	&iio_dev_attr_accel_y_offset.dev_attr.attr,
+	&iio_dev_attr_accel_z_offset.dev_attr.attr,
+	&iio_dev_attr_in_supply_raw.dev_attr.attr,
+	&iio_const_attr_in_supply_scale.dev_attr.attr,
+	&iio_dev_attr_gyro_x_raw.dev_attr.attr,
+	&iio_dev_attr_gyro_y_raw.dev_attr.attr,
+	&iio_dev_attr_gyro_z_raw.dev_attr.attr,
+	&iio_const_attr_gyro_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_const_attr_accel_scale.dev_attr.attr,
+	&iio_dev_attr_temp_x_raw.dev_attr.attr,
+	&iio_dev_attr_temp_y_raw.dev_attr.attr,
+	&iio_dev_attr_temp_z_raw.dev_attr.attr,
+	&iio_const_attr_temp_scale.dev_attr.attr,
+	&iio_dev_attr_in0_raw.dev_attr.attr,
+	&iio_const_attr_in0_scale.dev_attr.attr,
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	&iio_const_attr_available_sampling_frequency.dev_attr.attr,
+	&iio_dev_attr_reset.dev_attr.attr,
+	&iio_const_attr_name.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group adis16350_attribute_group = {
+	.attrs = adis16350_attributes,
+};
+
+static struct attribute *adis16350_event_attributes[] = {
+	NULL,
+};
+
+static struct attribute_group adis16350_event_attribute_group = {
+	.attrs = adis16350_event_attributes,
+};
+
+static int __devinit adis16350_probe(struct spi_device *spi)
+{
+	int ret, regdone = 0;
+	struct adis16350_state *st = kzalloc(sizeof *st, GFP_KERNEL);
+	if (!st) {
+		ret =  -ENOMEM;
+		goto error_ret;
+	}
+	/* this is only used for removal purposes */
+	spi_set_drvdata(spi, st);
+
+	/* Allocate the comms buffers */
+	st->rx = kzalloc(sizeof(*st->rx)*ADIS16350_MAX_RX, GFP_KERNEL);
+	if (st->rx == NULL) {
+		ret = -ENOMEM;
+		goto error_free_st;
+	}
+	st->tx = kzalloc(sizeof(*st->tx)*ADIS16350_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->indio_dev = iio_allocate_device();
+	if (st->indio_dev == NULL) {
+		ret = -ENOMEM;
+		goto error_free_tx;
+	}
+
+	st->indio_dev->dev.parent = &spi->dev;
+	st->indio_dev->num_interrupt_lines = 1;
+	st->indio_dev->event_attrs = &adis16350_event_attribute_group;
+	st->indio_dev->attrs = &adis16350_attribute_group;
+	st->indio_dev->dev_data = (void *)(st);
+	st->indio_dev->driver_module = THIS_MODULE;
+	st->indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = adis16350_configure_ring(st->indio_dev);
+	if (ret)
+		goto error_free_dev;
+
+	ret = iio_device_register(st->indio_dev);
+	if (ret)
+		goto error_unreg_ring_funcs;
+	regdone = 1;
+
+	ret = adis16350_initialize_ring(st->indio_dev->ring);
+	if (ret) {
+		printk(KERN_ERR "failed to initialize the ring\n");
+		goto error_unreg_ring_funcs;
+	}
+
+	if (spi->irq) {
+		ret = iio_register_interrupt_line(spi->irq,
+				st->indio_dev,
+				0,
+				IRQF_TRIGGER_RISING,
+				"adis16350");
+		if (ret)
+			goto error_uninitialize_ring;
+
+		ret = adis16350_probe_trigger(st->indio_dev);
+		if (ret)
+			goto error_unregister_line;
+	}
+
+	/* Get the device into a sane initial state */
+	ret = adis16350_initial_setup(st);
+	if (ret)
+		goto error_remove_trigger;
+	return 0;
+
+error_remove_trigger:
+	adis16350_remove_trigger(st->indio_dev);
+error_unregister_line:
+	if (spi->irq)
+		iio_unregister_interrupt_line(st->indio_dev, 0);
+error_uninitialize_ring:
+	adis16350_uninitialize_ring(st->indio_dev->ring);
+error_unreg_ring_funcs:
+	adis16350_unconfigure_ring(st->indio_dev);
+error_free_dev:
+	if (regdone)
+		iio_device_unregister(st->indio_dev);
+	else
+		iio_free_device(st->indio_dev);
+error_free_tx:
+	kfree(st->tx);
+error_free_rx:
+	kfree(st->rx);
+error_free_st:
+	kfree(st);
+error_ret:
+	return ret;
+}
+
+static int adis16350_remove(struct spi_device *spi)
+{
+	int ret;
+	struct adis16350_state *st = spi_get_drvdata(spi);
+	struct iio_dev *indio_dev = st->indio_dev;
+
+	ret = adis16350_stop_device(&(indio_dev->dev));
+	if (ret)
+		goto err_ret;
+
+	flush_scheduled_work();
+
+	adis16350_remove_trigger(indio_dev);
+	if (spi->irq)
+		iio_unregister_interrupt_line(indio_dev, 0);
+
+	adis16350_uninitialize_ring(indio_dev->ring);
+	iio_device_unregister(indio_dev);
+	adis16350_unconfigure_ring(indio_dev);
+	kfree(st->tx);
+	kfree(st->rx);
+	kfree(st);
+
+	return 0;
+
+err_ret:
+	return ret;
+}
+
+static const struct spi_device_id adis16350_id[] = {
+	{"adis16350", 0},
+	{"adis16354", 0},
+	{"adis16355", 0},
+	{"adis16360", 0},
+	{"adis16362", 0},
+	{"adis16364", 0},
+	{"adis16365", 0},
+	{}
+};
+
+static struct spi_driver adis16350_driver = {
+	.driver = {
+		.name = "adis16350",
+		.owner = THIS_MODULE,
+	},
+	.probe = adis16350_probe,
+	.remove = __devexit_p(adis16350_remove),
+	.id_table = adis16350_id,
+};
+
+static __init int adis16350_init(void)
+{
+	return spi_register_driver(&adis16350_driver);
+}
+module_init(adis16350_init);
+
+static __exit void adis16350_exit(void)
+{
+	spi_unregister_driver(&adis16350_driver);
+}
+module_exit(adis16350_exit);
+
+MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
+MODULE_DESCRIPTION("Analog Devices ADIS16350/54/55/60/62/64/65 IMU SPI driver");
+MODULE_LICENSE("GPL v2");

drivers/staging/iio/imu/adis16350_ring.c

+#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/sysfs.h>
+#include <linux/list.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../ring_sw.h"
+#include "../accel/accel.h"
+#include "../trigger.h"
+#include "adis16350.h"
+
+/**
+ * combine_8_to_16() utility function to munge to u8s into u16
+ **/
+static inline u16 combine_8_to_16(u8 lower, u8 upper)
+{
+	u16 _lower = lower;
+	u16 _upper = upper;
+	return _lower | (_upper << 8);
+}
+
+static IIO_SCAN_EL_C(supply, ADIS16350_SCAN_SUPPLY, IIO_UNSIGNED(12),
+		ADIS16350_SUPPLY_OUT, NULL);
+
+static IIO_SCAN_EL_C(gyro_x, ADIS16350_SCAN_GYRO_X, IIO_SIGNED(14),
+		ADIS16350_XGYRO_OUT, NULL);
+static IIO_SCAN_EL_C(gyro_y, ADIS16350_SCAN_GYRO_Y, IIO_SIGNED(14),
+		ADIS16350_YGYRO_OUT, NULL);
+static IIO_SCAN_EL_C(gyro_z, ADIS16350_SCAN_GYRO_Z, IIO_SIGNED(14),
+		ADIS16350_ZGYRO_OUT, NULL);
+
+static IIO_SCAN_EL_C(accel_x, ADIS16350_SCAN_ACC_X, IIO_SIGNED(14),
+		ADIS16350_XACCL_OUT, NULL);
+static IIO_SCAN_EL_C(accel_y, ADIS16350_SCAN_ACC_Y, IIO_SIGNED(14),
+		ADIS16350_YACCL_OUT, NULL);
+static IIO_SCAN_EL_C(accel_z, ADIS16350_SCAN_ACC_Z, IIO_SIGNED(14),
+		ADIS16350_ZACCL_OUT, NULL);
+
+static IIO_SCAN_EL_C(temp_x, ADIS16350_SCAN_TEMP_X, IIO_SIGNED(12),
+		ADIS16350_XTEMP_OUT, NULL);
+static IIO_SCAN_EL_C(temp_y, ADIS16350_SCAN_TEMP_Y, IIO_SIGNED(12),
+		ADIS16350_YTEMP_OUT, NULL);
+static IIO_SCAN_EL_C(temp_z, ADIS16350_SCAN_TEMP_Z, IIO_SIGNED(12),
+		ADIS16350_ZTEMP_OUT, NULL);
+
+static IIO_SCAN_EL_C(adc_0, ADIS16350_SCAN_ADC_0, IIO_UNSIGNED(12),
+		ADIS16350_AUX_ADC, NULL);
+
+static IIO_SCAN_EL_TIMESTAMP(11);
+
+static struct attribute *adis16350_scan_el_attrs[] = {
+	&iio_scan_el_supply.dev_attr.attr,
+	&iio_scan_el_gyro_x.dev_attr.attr,
+	&iio_scan_el_gyro_y.dev_attr.attr,
+	&iio_scan_el_gyro_z.dev_attr.attr,
+	&iio_scan_el_accel_x.dev_attr.attr,
+	&iio_scan_el_accel_y.dev_attr.attr,
+	&iio_scan_el_accel_z.dev_attr.attr,
+	&iio_scan_el_temp_x.dev_attr.attr,
+	&iio_scan_el_temp_y.dev_attr.attr,
+	&iio_scan_el_temp_z.dev_attr.attr,
+	&iio_scan_el_adc_0.dev_attr.attr,
+	&iio_scan_el_timestamp.dev_attr.attr,
+	NULL,
+};
+
+static struct attribute_group adis16350_scan_el_group = {
+	.attrs = adis16350_scan_el_attrs,
+	.name = "scan_elements",
+};
+
+/**
+ * adis16350_poll_func_th() top half interrupt handler called by trigger
+ * @private_data:	iio_dev
+ **/
+static void adis16350_poll_func_th(struct iio_dev *indio_dev)
+{
+	struct adis16350_state *st = iio_dev_get_devdata(indio_dev);
+	st->last_timestamp = indio_dev->trig->timestamp;
+	schedule_work(&st->work_trigger_to_ring);
+}
+
+/**
+ * adis16350_spi_read_burst() - read all data registers
+ * @dev: device associated with child of actual device (iio_dev or iio_trig)
+ * @rx: somewhere to pass back the value read (min size is 24 bytes)
+ **/
+static int adis16350_spi_read_burst(struct device *dev, u8 *rx)
+{
+	struct spi_message msg;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct adis16350_state *st = iio_dev_get_devdata(indio_dev);
+	u32 old_speed_hz = st->us->max_speed_hz;
+	int ret;
+
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = st->tx,
+			.bits_per_word = 8,
+			.len = 2,
+			.cs_change = 0,
+		}, {
+			.rx_buf = rx,
+			.bits_per_word = 8,
+			.len = 22,
+			.cs_change = 0,
+		},
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADIS16350_READ_REG(ADIS16350_GLOB_CMD);
+	st->tx[1] = 0;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfers[0], &msg);
+	spi_message_add_tail(&xfers[1], &msg);
+
+	st->us->max_speed_hz = ADIS16350_SPI_BURST;
+	spi_setup(st->us);
+
+	ret = spi_sync(st->us, &msg);
+	if (ret)
+		dev_err(&st->us->dev, "problem when burst reading");
+
+	st->us->max_speed_hz = old_speed_hz;
+	spi_setup(st->us);
+	mutex_unlock(&st->buf_lock);
+	return ret;
+}
+
+/* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
+ * specific to be rolled into the core.
+ */
+static void adis16350_trigger_bh_to_ring(struct work_struct *work_s)
+{
+	struct adis16350_state *st
+		= container_of(work_s, struct adis16350_state,
+			       work_trigger_to_ring);
+
+	int i = 0;
+	s16 *data;
+	size_t datasize = st->indio_dev
+		->ring->access.get_bpd(st->indio_dev->ring);
+
+	data = kmalloc(datasize , GFP_KERNEL);
+	if (data == NULL) {
+		dev_err(&st->us->dev, "memory alloc failed in ring bh");
+		return;
+	}
+
+	if (st->indio_dev->scan_count)
+		if (adis16350_spi_read_burst(&st->indio_dev->dev, st->rx) >= 0)
+			for (; i < st->indio_dev->scan_count; i++) {
+				data[i] = combine_8_to_16(st->rx[i*2+1],
+							  st->rx[i*2]);
+			}
+
+	/* Guaranteed to be aligned with 8 byte boundary */
+	if (st->indio_dev->scan_timestamp)
+		*((s64 *)(data + ((i + 3)/4)*4)) = st->last_timestamp;
+
+	st->indio_dev->ring->access.store_to(st->indio_dev->ring,
+					    (u8 *)data,
+					    st->last_timestamp);
+
+	iio_trigger_notify_done(st->indio_dev->trig);
+	kfree(data);
+
+	return;
+}
+
+static int adis16350_data_rdy_ring_preenable(struct iio_dev *indio_dev)
+{
+	size_t size;
+	dev_dbg(&indio_dev->dev, "%s\n", __func__);
+	/* Check if there are any scan elements enabled, if not fail*/
+	if (!(indio_dev->scan_count || indio_dev->scan_timestamp))
+		return -EINVAL;
+
+	if (indio_dev->ring->access.set_bpd) {
+		if (indio_dev->scan_timestamp)
+			if (indio_dev->scan_count)
+				/* Timestamp (aligned sizeof(s64) and data */
+				size = (((indio_dev->scan_count * sizeof(s16))
+						+ sizeof(s64) - 1)
+					& ~(sizeof(s64) - 1))
+					+ sizeof(s64);
+			else /* Timestamp only  */
+				size = sizeof(s64);
+		else /* Data only */
+			size = indio_dev->scan_count*sizeof(s16);
+		indio_dev->ring->access.set_bpd(indio_dev->ring, size);
+	}
+
+	return 0;
+}
+
+static int adis16350_data_rdy_ring_postenable(struct iio_dev *indio_dev)
+{
+	return indio_dev->trig
+		? iio_trigger_attach_poll_func(indio_dev->trig,
+					       indio_dev->pollfunc)
+		: 0;
+}
+
+static int adis16350_data_rdy_ring_predisable(struct iio_dev *indio_dev)
+{
+	return indio_dev->trig
+		? iio_trigger_dettach_poll_func(indio_dev->trig,
+						indio_dev->pollfunc)
+		: 0;
+}
+
+void adis16350_unconfigure_ring(struct iio_dev *indio_dev)
+{
+	kfree(indio_dev->pollfunc);
+	iio_sw_rb_free(indio_dev->ring);
+}
+
+int adis16350_configure_ring(struct iio_dev *indio_dev)
+{
+	int ret = 0;
+	struct adis16350_state *st = indio_dev->dev_data;
+	struct iio_ring_buffer *ring;
+	INIT_WORK(&st->work_trigger_to_ring, adis16350_trigger_bh_to_ring);
+	/* Set default scan mode */
+
+	iio_scan_mask_set(indio_dev, iio_scan_el_supply.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_gyro_x.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_gyro_y.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_gyro_z.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_accel_x.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_accel_y.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_accel_z.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_temp_x.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_temp_y.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_temp_z.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_adc_0.number);
+	indio_dev->scan_timestamp = true;
+
+	indio_dev->scan_el_attrs = &adis16350_scan_el_group;
+
+	ring = iio_sw_rb_allocate(indio_dev);
+	if (!ring) {
+		ret = -ENOMEM;
+		return ret;
+	}
+	indio_dev->ring = ring;
+	/* Effectively select the ring buffer implementation */
+	iio_ring_sw_register_funcs(&ring->access);
+	ring->preenable = &adis16350_data_rdy_ring_preenable;
+	ring->postenable = &adis16350_data_rdy_ring_postenable;
+	ring->predisable = &adis16350_data_rdy_ring_predisable;
+	ring->owner = THIS_MODULE;
+
+	indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
+	if (indio_dev->pollfunc == NULL) {
+		ret = -ENOMEM;
+		goto error_iio_sw_rb_free;;
+	}
+	indio_dev->pollfunc->poll_func_main = &adis16350_poll_func_th;
+	indio_dev->pollfunc->private_data = indio_dev;
+	indio_dev->modes |= INDIO_RING_TRIGGERED;
+	return 0;
+
+error_iio_sw_rb_free:
+	iio_sw_rb_free(indio_dev->ring);
+	return ret;
+}
+
+int adis16350_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return iio_ring_buffer_register(ring, 0);
+}
+
+void adis16350_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+	iio_ring_buffer_unregister(ring);
+}

drivers/staging/iio/imu/adis16350_trigger.c

+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+#include <linux/spi/spi.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "../trigger.h"
+#include "adis16350.h"
+
+/**
+ * adis16350_data_rdy_trig_poll() the event handler for the data rdy trig
+ **/
+static int adis16350_data_rdy_trig_poll(struct iio_dev *dev_info,
+				       int index,
+				       s64 timestamp,
+				       int no_test)
+{
+	struct adis16350_state *st = iio_dev_get_devdata(dev_info);
+	struct iio_trigger *trig = st->trig;
+
+	trig->timestamp = timestamp;
+	iio_trigger_poll(trig);
+
+	return IRQ_HANDLED;
+}
+
+IIO_EVENT_SH(data_rdy_trig, &adis16350_data_rdy_trig_poll);
+
+static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
+
+static struct attribute *adis16350_trigger_attrs[] = {
+	&dev_attr_name.attr,
+	NULL,
+};
+
+static const struct attribute_group adis16350_trigger_attr_group = {
+	.attrs = adis16350_trigger_attrs,
+};
+
+/**
+ * adis16350_data_rdy_trigger_set_state() set datardy interrupt state
+ **/
+static int adis16350_data_rdy_trigger_set_state(struct iio_trigger *trig,
+						bool state)
+{
+	struct adis16350_state *st = trig->private_data;
+	struct iio_dev *indio_dev = st->indio_dev;
+	int ret = 0;
+
+	dev_dbg(&indio_dev->dev, "%s (%d)\n", __func__, state);
+	ret = adis16350_set_irq(&st->indio_dev->dev, state);
+	if (state == false) {
+		iio_remove_event_from_list(&iio_event_data_rdy_trig,
+					   &indio_dev->interrupts[0]
+					   ->ev_list);
+		/* possible quirk with handler currently worked around
+		   by ensuring the work queue is empty */
+		flush_scheduled_work();
+	} else {
+		iio_add_event_to_list(&iio_event_data_rdy_trig,
+				      &indio_dev->interrupts[0]->ev_list);
+	}
+	return ret;
+}
+
+/**
+ * adis16350_trig_try_reen() try renabling irq for data rdy trigger
+ * @trig:	the datardy trigger
+ **/
+static int adis16350_trig_try_reen(struct iio_trigger *trig)
+{
+	struct adis16350_state *st = trig->private_data;
+	enable_irq(st->us->irq);
+	/* irq reenabled so success! */
+	return 0;
+}
+
+int adis16350_probe_trigger(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct adis16350_state *st = indio_dev->dev_data;
+
+	st->trig = iio_allocate_trigger();
+	st->trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
+	if (!st->trig->name) {
+		ret = -ENOMEM;
+		goto error_free_trig;
+	}
+	snprintf((char *)st->trig->name,
+		 IIO_TRIGGER_NAME_LENGTH,
+		 "adis16350-dev%d", indio_dev->id);
+	st->trig->dev.parent = &st->us->dev;
+	st->trig->owner = THIS_MODULE;
+	st->trig->private_data = st;
+	st->trig->set_trigger_state = &adis16350_data_rdy_trigger_set_state;
+	st->trig->try_reenable = &adis16350_trig_try_reen;
+	st->trig->control_attrs = &adis16350_trigger_attr_group;
+	ret = iio_trigger_register(st->trig);
+
+	/* select default trigger */
+	indio_dev->trig = st->trig;
+	if (ret)
+		goto error_free_trig_name;
+
+	return 0;
+
+error_free_trig_name:
+	kfree(st->trig->name);
+error_free_trig:
+	iio_free_trigger(st->trig);
+
+	return ret;
+}
+
+void adis16350_remove_trigger(struct iio_dev *indio_dev)
+{
+	struct adis16350_state *state = indio_dev->dev_data;
+
+	iio_trigger_unregister(state->trig);
+	kfree(state->trig->name);
+	iio_free_trigger(state->trig);
+}