staging:iio:imu ADIS16300 driver

Signed-off-by: Barry Song <Barry.Song@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/Kconfig

@@ -41,6 +41,7 @@ config IIO_TRIGGER
 
 source "drivers/staging/iio/accel/Kconfig"
 source "drivers/staging/iio/adc/Kconfig"
+source "drivers/staging/iio/imu/Kconfig"
 source "drivers/staging/iio/light/Kconfig"
 
 source "drivers/staging/iio/trigger/Kconfig"

drivers/staging/iio/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_IIO_SW_RING) += ring_sw.o
 
 obj-y += accel/
 obj-y += adc/
+obj-y += imu/
 obj-y += light/
 
 obj-y += trigger/
\ No newline at end of file

drivers/staging/iio/adc/adc.h

@@ -16,6 +16,9 @@
 #define IIO_DEV_ATTR_IN_RAW(_num, _show, _addr)				\
 	IIO_DEVICE_ATTR(in##_num##_raw, S_IRUGO, _show, NULL, _addr)
 
+#define IIO_DEV_ATTR_IN_NAMED_RAW(_name, _show, _addr)			\
+	IIO_DEVICE_ATTR(in_##_name##_raw, S_IRUGO, _show, NULL, _addr)
+
 #define IIO_DEV_ATTR_IN_DIFF_RAW(_nump, _numn, _show, _addr)		\
 	IIO_DEVICE_ATTR_NAMED(in##_nump##min##_numn##_raw,		\
 			      in##_nump-in##_numn##_raw,		\

drivers/staging/iio/gyro/gyro.h

+
+#include "../sysfs.h"
+
+/* Gyroscope types of attribute */
+
+#define IIO_DEV_ATTR_GYRO_OFFSET(_mode, _show, _store, _addr)	\
+	IIO_DEVICE_ATTR(gyro_offset, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_GYRO_X_OFFSET(_mode, _show, _store, _addr)	\
+	IIO_DEVICE_ATTR(gyro_x_offset, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_GYRO_Y_OFFSET(_mode, _show, _store, _addr)	\
+	IIO_DEVICE_ATTR(gyro_y_offset, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_GYRO_Z_OFFSET(_mode, _show, _store, _addr)	\
+	IIO_DEVICE_ATTR(gyro_z_offset, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_GYRO_X_GAIN(_mode, _show, _store, _addr)		\
+	IIO_DEVICE_ATTR(gyro_x_gain, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_GYRO_Y_GAIN(_mode, _show, _store, _addr)		\
+	IIO_DEVICE_ATTR(gyro_y_gain, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_GYRO_Z_GAIN(_mode, _show, _store, _addr)		\
+	IIO_DEVICE_ATTR(gyro_z_gain, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_GYRO_SCALE(_mode, _show, _store, _addr)		\
+	IIO_DEVICE_ATTR(gyro_scale, S_IRUGO, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_GYRO(_show, _addr)			\
+	IIO_DEVICE_ATTR(gyro, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_GYRO_X(_show, _addr)			\
+	IIO_DEVICE_ATTR(gyro_x, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_GYRO_Y(_show, _addr)			\
+	IIO_DEVICE_ATTR(gyro_y, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_GYRO_Z(_show, _addr)			\
+	IIO_DEVICE_ATTR(gyro_z, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_TEMP_X(_show, _addr)			\
+	IIO_DEVICE_ATTR(temp_x, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_TEMP_Y(_show, _addr)			\
+	IIO_DEVICE_ATTR(temp_y, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_TEMP_Z(_show, _addr)			\
+	IIO_DEVICE_ATTR(temp_z, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_INCLI_X(_show, _addr)			\
+	IIO_DEVICE_ATTR(incli_x, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_INCLI_Y(_show, _addr)			\
+	IIO_DEVICE_ATTR(incli_y, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_INCLI_Z(_show, _addr)			\
+	IIO_DEVICE_ATTR(incli_z, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_INCLI_X_OFFSET(_mode, _show, _store, _addr) \
+	IIO_DEVICE_ATTR(incli_x_offset, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_INCLI_Y_OFFSET(_mode, _show, _store, _addr) \
+	IIO_DEVICE_ATTR(incli_y_offset, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_INCLI_Z_OFFSET(_mode, _show, _store, _addr) \
+	IIO_DEVICE_ATTR(incli_z_offset, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_ROT(_show, _addr)                    \
+	IIO_DEVICE_ATTR(rot, S_IRUGO, _show, NULL, _addr)
+
+#define IIO_DEV_ATTR_ROT_OFFSET(_mode, _show, _store, _addr) \
+	IIO_DEVICE_ATTR(rot_offset, _mode, _show, _store, _addr)
+
+#define IIO_DEV_ATTR_ANGL(_show, _addr)                         \
+	IIO_DEVICE_ATTR(angl, S_IRUGO, _show, NULL, _addr)

drivers/staging/iio/imu/Kconfig

+#
+# IIO imu drivers configuration
+#
+comment "Inertial measurement units"
+
+config ADIS16300
+	tristate "Analog Devices ADIS16300 IMU SPI driver"
+	depends on SPI
+	select IIO_SW_RING
+	select IIO_RING_BUFFER
+	select IIO_TRIGGER
+	help
+	  Say yes here to build support for Analog Devices adis16300 four degrees
+	  of freedom inertial sensor.

drivers/staging/iio/imu/Makefile

+#
+# Makefile for Inertial Measurement Units
+#
+adis16300-y             := adis16300_core.o
+adis16300-$(CONFIG_IIO_RING_BUFFER) += adis16300_ring.o adis16300_trigger.o
+obj-$(CONFIG_ADIS16300) += adis16300.o

drivers/staging/iio/imu/adis16300.h

+#ifndef SPI_ADIS16300_H_
+#define SPI_ADIS16300_H_
+
+#define ADIS16300_STARTUP_DELAY	220 /* ms */
+
+#define ADIS16300_READ_REG(a)    a
+#define ADIS16300_WRITE_REG(a) ((a) | 0x80)
+
+#define ADIS16300_FLASH_CNT  0x00 /* Flash memory write count */
+#define ADIS16300_SUPPLY_OUT 0x02 /* Power supply measurement */
+#define ADIS16300_XGYRO_OUT 0x04 /* X-axis gyroscope output */
+#define ADIS16300_XACCL_OUT 0x0A /* X-axis accelerometer output */
+#define ADIS16300_YACCL_OUT 0x0C /* Y-axis accelerometer output */
+#define ADIS16300_ZACCL_OUT 0x0E /* Z-axis accelerometer output */
+#define ADIS16300_TEMP_OUT  0x10 /* Temperature output */
+#define ADIS16300_XINCLI_OUT 0x12 /* X-axis inclinometer output measurement */
+#define ADIS16300_YINCLI_OUT 0x14 /* Y-axis inclinometer output measurement */
+#define ADIS16300_AUX_ADC   0x16 /* Auxiliary ADC measurement */
+
+/* Calibration parameters */
+#define ADIS16300_XGYRO_OFF 0x1A /* X-axis gyroscope bias offset factor */
+#define ADIS16300_XACCL_OFF 0x20 /* X-axis acceleration bias offset factor */
+#define ADIS16300_YACCL_OFF 0x22 /* Y-axis acceleration bias offset factor */
+#define ADIS16300_ZACCL_OFF 0x24 /* Z-axis acceleration bias offset factor */
+
+#define ADIS16300_GPIO_CTRL 0x32 /* Auxiliary digital input/output control */
+#define ADIS16300_MSC_CTRL  0x34 /* Miscellaneous control */
+#define ADIS16300_SMPL_PRD  0x36 /* Internal sample period (rate) control */
+#define ADIS16300_SENS_AVG  0x38 /* Dynamic range and digital filter control */
+#define ADIS16300_SLP_CNT   0x3A /* Sleep mode control */
+#define ADIS16300_DIAG_STAT 0x3C /* System status */
+
+/* Alarm functions */
+#define ADIS16300_GLOB_CMD  0x3E /* System command */
+#define ADIS16300_ALM_MAG1  0x26 /* Alarm 1 amplitude threshold */
+#define ADIS16300_ALM_MAG2  0x28 /* Alarm 2 amplitude threshold */
+#define ADIS16300_ALM_SMPL1 0x2A /* Alarm 1 sample size */
+#define ADIS16300_ALM_SMPL2 0x2C /* Alarm 2 sample size */
+#define ADIS16300_ALM_CTRL  0x2E /* Alarm control */
+#define ADIS16300_AUX_DAC   0x30 /* Auxiliary DAC data */
+
+#define ADIS16300_ERROR_ACTIVE			(1<<14)
+#define ADIS16300_NEW_DATA			(1<<15)
+
+/* MSC_CTRL */
+#define ADIS16300_MSC_CTRL_MEM_TEST		(1<<11)
+#define ADIS16300_MSC_CTRL_INT_SELF_TEST	(1<<10)
+#define ADIS16300_MSC_CTRL_NEG_SELF_TEST	(1<<9)
+#define ADIS16300_MSC_CTRL_POS_SELF_TEST	(1<<8)
+#define ADIS16300_MSC_CTRL_GYRO_BIAS		(1<<7)
+#define ADIS16300_MSC_CTRL_ACCL_ALIGN		(1<<6)
+#define ADIS16300_MSC_CTRL_DATA_RDY_EN		(1<<2)
+#define ADIS16300_MSC_CTRL_DATA_RDY_POL_HIGH	(1<<1)
+#define ADIS16300_MSC_CTRL_DATA_RDY_DIO2	(1<<0)
+
+/* SMPL_PRD */
+#define ADIS16300_SMPL_PRD_TIME_BASE	(1<<7)
+#define ADIS16300_SMPL_PRD_DIV_MASK	0x7F
+
+/* DIAG_STAT */
+#define ADIS16300_DIAG_STAT_ZACCL_FAIL	(1<<15)
+#define ADIS16300_DIAG_STAT_YACCL_FAIL	(1<<14)
+#define ADIS16300_DIAG_STAT_XACCL_FAIL	(1<<13)
+#define ADIS16300_DIAG_STAT_XGYRO_FAIL	(1<<10)
+#define ADIS16300_DIAG_STAT_ALARM2	(1<<9)
+#define ADIS16300_DIAG_STAT_ALARM1	(1<<8)
+#define ADIS16300_DIAG_STAT_FLASH_CHK	(1<<6)
+#define ADIS16300_DIAG_STAT_SELF_TEST	(1<<5)
+#define ADIS16300_DIAG_STAT_OVERFLOW	(1<<4)
+#define ADIS16300_DIAG_STAT_SPI_FAIL	(1<<3)
+#define ADIS16300_DIAG_STAT_FLASH_UPT	(1<<2)
+#define ADIS16300_DIAG_STAT_POWER_HIGH	(1<<1)
+#define ADIS16300_DIAG_STAT_POWER_LOW	(1<<0)
+
+/* GLOB_CMD */
+#define ADIS16300_GLOB_CMD_SW_RESET	(1<<7)
+#define ADIS16300_GLOB_CMD_P_AUTO_NULL	(1<<4)
+#define ADIS16300_GLOB_CMD_FLASH_UPD	(1<<3)
+#define ADIS16300_GLOB_CMD_DAC_LATCH	(1<<2)
+#define ADIS16300_GLOB_CMD_FAC_CALIB	(1<<1)
+#define ADIS16300_GLOB_CMD_AUTO_NULL	(1<<0)
+
+/* SLP_CNT */
+#define ADIS16300_SLP_CNT_POWER_OFF	(1<<8)
+
+#define ADIS16300_MAX_TX 18
+#define ADIS16300_MAX_RX 18
+
+#define ADIS16300_SPI_SLOW	(u32)(300 * 1000)
+#define ADIS16300_SPI_BURST	(u32)(1000 * 1000)
+#define ADIS16300_SPI_FAST	(u32)(2000 * 1000)
+
+/**
+ * struct adis16300_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 adis16300_state {
+	struct spi_device		*us;
+	struct work_struct		work_trigger_to_ring;
+	struct iio_work_cont		work_cont_thresh;
+	s64				last_timestamp;
+	struct iio_dev			*indio_dev;
+	struct iio_trigger		*trig;
+	u8				*tx;
+	u8				*rx;
+	struct mutex			buf_lock;
+};
+
+int adis16300_spi_write_reg_8(struct device *dev,
+			      u8 reg_address,
+			      u8 val);
+
+int adis16300_spi_read_burst(struct device *dev, u8 *rx);
+
+int adis16300_spi_read_sequence(struct device *dev,
+				      u8 *tx, u8 *rx, int num);
+
+int adis16300_set_irq(struct device *dev, bool enable);
+
+int adis16300_reset(struct device *dev);
+
+int adis16300_stop_device(struct device *dev);
+
+int adis16300_check_status(struct device *dev);
+
+#ifdef CONFIG_IIO_RING_BUFFER
+/* At the moment triggers are only used for ring buffer
+ * filling. This may change!
+ */
+
+enum adis16300_scan {
+	ADIS16300_SCAN_SUPPLY,
+	ADIS16300_SCAN_GYRO_X,
+	ADIS16300_SCAN_ACC_X,
+	ADIS16300_SCAN_ACC_Y,
+	ADIS16300_SCAN_ACC_Z,
+	ADIS16300_SCAN_TEMP,
+	ADIS16300_SCAN_ADC_0,
+	ADIS16300_SCAN_INCLI_X,
+	ADIS16300_SCAN_INCLI_Y,
+};
+
+void adis16300_remove_trigger(struct iio_dev *indio_dev);
+int adis16300_probe_trigger(struct iio_dev *indio_dev);
+
+ssize_t adis16300_read_data_from_ring(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf);
+
+
+int adis16300_configure_ring(struct iio_dev *indio_dev);
+void adis16300_unconfigure_ring(struct iio_dev *indio_dev);
+
+int adis16300_initialize_ring(struct iio_ring_buffer *ring);
+void adis16300_uninitialize_ring(struct iio_ring_buffer *ring);
+#else /* CONFIG_IIO_RING_BUFFER */
+
+static inline void adis16300_remove_trigger(struct iio_dev *indio_dev)
+{
+}
+
+static inline int adis16300_probe_trigger(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline ssize_t
+adis16300_read_data_from_ring(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	return 0;
+}
+
+static int adis16300_configure_ring(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline void adis16300_unconfigure_ring(struct iio_dev *indio_dev)
+{
+}
+
+static inline int adis16300_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return 0;
+}
+
+static inline void adis16300_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+}
+
+#endif /* CONFIG_IIO_RING_BUFFER */
+#endif /* SPI_ADIS16300_H_ */

drivers/staging/iio/imu/adis16300_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 "adis16300.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, ADIS16300_SCAN_SUPPLY, IIO_SIGNED(14),
+		     ADIS16300_SUPPLY_OUT, NULL);
+
+static IIO_SCAN_EL_C(gyro_x, ADIS16300_SCAN_GYRO_X, IIO_SIGNED(14),
+		     ADIS16300_XGYRO_OUT, NULL);
+
+static IIO_SCAN_EL_C(accel_x, ADIS16300_SCAN_ACC_X, IIO_SIGNED(14),
+		     ADIS16300_XACCL_OUT, NULL);
+static IIO_SCAN_EL_C(accel_y, ADIS16300_SCAN_ACC_Y, IIO_SIGNED(14),
+		     ADIS16300_YACCL_OUT, NULL);
+static IIO_SCAN_EL_C(accel_z, ADIS16300_SCAN_ACC_Z, IIO_SIGNED(14),
+		     ADIS16300_ZACCL_OUT, NULL);
+
+static IIO_SCAN_EL_C(temp, ADIS16300_SCAN_TEMP, IIO_SIGNED(12),
+		     ADIS16300_TEMP_OUT, NULL);
+static IIO_SCAN_EL_C(adc_0, ADIS16300_SCAN_ADC_0, IIO_SIGNED(12),
+		     ADIS16300_AUX_ADC, NULL);
+
+static IIO_SCAN_EL_C(incli_x, ADIS16300_SCAN_INCLI_X, IIO_SIGNED(12),
+		     ADIS16300_XINCLI_OUT, NULL);
+static IIO_SCAN_EL_C(incli_y, ADIS16300_SCAN_INCLI_Y, IIO_SIGNED(12),
+		     ADIS16300_YINCLI_OUT, NULL);
+
+static IIO_SCAN_EL_TIMESTAMP(9);
+
+static struct attribute *adis16300_scan_el_attrs[] = {
+	&iio_scan_el_supply.dev_attr.attr,
+	&iio_scan_el_gyro_x.dev_attr.attr,
+	&iio_scan_el_temp.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_incli_x.dev_attr.attr,
+	&iio_scan_el_incli_y.dev_attr.attr,
+	&iio_scan_el_adc_0.dev_attr.attr,
+	&iio_scan_el_timestamp.dev_attr.attr,
+	NULL,
+};
+
+static struct attribute_group adis16300_scan_el_group = {
+	.attrs = adis16300_scan_el_attrs,
+	.name = "scan_elements",
+};
+
+/**
+ * adis16300_poll_func_th() top half interrupt handler called by trigger
+ * @private_data:	iio_dev
+ **/
+static void adis16300_poll_func_th(struct iio_dev *indio_dev)
+{
+	struct adis16300_state *st = iio_dev_get_devdata(indio_dev);
+	st->last_timestamp = indio_dev->trig->timestamp;
+	schedule_work(&st->work_trigger_to_ring);
+	/* Indicate that this interrupt is being handled */
+
+	/* Technically this is trigger related, but without this
+	 * handler running there is currently no way for the interrupt
+	 * to clear.
+	 */
+}
+
+/* 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 adis16300_trigger_bh_to_ring(struct work_struct *work_s)
+{
+	struct adis16300_state *st
+		= container_of(work_s, struct adis16300_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 (adis16300_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;
+}
+/* in these circumstances is it better to go with unaligned packing and
+ * deal with the cost?*/
+static int adis16300_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 and data */
+				size = 4*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 adis16300_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 adis16300_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 adis16300_unconfigure_ring(struct iio_dev *indio_dev)
+{
+	kfree(indio_dev->pollfunc);
+	iio_sw_rb_free(indio_dev->ring);
+}
+
+int adis16300_configure_ring(struct iio_dev *indio_dev)
+{
+	int ret = 0;
+	struct adis16300_state *st = indio_dev->dev_data;
+	struct iio_ring_buffer *ring;
+	INIT_WORK(&st->work_trigger_to_ring, adis16300_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_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.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_adc_0.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_incli_x.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_incli_y.number);
+	indio_dev->scan_timestamp = true;
+
+	indio_dev->scan_el_attrs = &adis16300_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 = &adis16300_data_rdy_ring_preenable;
+	ring->postenable = &adis16300_data_rdy_ring_postenable;
+	ring->predisable = &adis16300_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 = &adis16300_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 adis16300_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return iio_ring_buffer_register(ring, 0);
+}
+
+void adis16300_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+	iio_ring_buffer_unregister(ring);
+}

drivers/staging/iio/imu/adis16300_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 "adis16300.h"
+
+/**
+ * adis16300_data_rdy_trig_poll() the event handler for the data rdy trig
+ **/
+static int adis16300_data_rdy_trig_poll(struct iio_dev *dev_info,
+				       int index,
+				       s64 timestamp,
+				       int no_test)
+{
+	struct adis16300_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, &adis16300_data_rdy_trig_poll);
+
+static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
+
+static struct attribute *adis16300_trigger_attrs[] = {
+	&dev_attr_name.attr,
+	NULL,
+};
+
+static const struct attribute_group adis16300_trigger_attr_group = {
+	.attrs = adis16300_trigger_attrs,
+};
+
+/**
+ * adis16300_data_rdy_trigger_set_state() set datardy interrupt state
+ **/
+static int adis16300_data_rdy_trigger_set_state(struct iio_trigger *trig,
+						bool state)
+{
+	struct adis16300_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 = adis16300_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;
+}
+
+/**
+ * adis16300_trig_try_reen() try renabling irq for data rdy trigger
+ * @trig:	the datardy trigger
+ **/
+static int adis16300_trig_try_reen(struct iio_trigger *trig)
+{
+	struct adis16300_state *st = trig->private_data;
+	enable_irq(st->us->irq);
+	/* irq reenabled so success! */
+	return 0;
+}
+
+int adis16300_probe_trigger(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct adis16300_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,
+		 "adis16300-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 = &adis16300_data_rdy_trigger_set_state;
+	st->trig->try_reenable = &adis16300_trig_try_reen;
+	st->trig->control_attrs = &adis16300_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 adis16300_remove_trigger(struct iio_dev *indio_dev)
+{
+	struct adis16300_state *state = indio_dev->dev_data;
+
+	iio_trigger_unregister(state->trig);
+	kfree(state->trig->name);
+	iio_free_trigger(state->trig);
+}