staging: iio: adis16260 digital gyro driver

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/Kconfig

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

drivers/staging/iio/gyro/Kconfig

+#
+# IIO Digital Gyroscope Sensor drivers configuration
+#
+comment "Digital gyroscope sensors"
+
+config ADIS16260
+	tristate "Analog Devices ADIS16260/5 Digital Gyroscope Sensor 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 adis16260/5
+	  programmable digital gyroscope sensor.

drivers/staging/iio/gyro/Makefile

+
+# Makefile for digital gyroscope sensor drivers
+#
+
+adis16260-y             := adis16260_core.o
+adis16260-$(CONFIG_IIO_RING_BUFFER) += adis16260_ring.o adis16260_trigger.o
+obj-$(CONFIG_ADIS16260) += adis16260.o

drivers/staging/iio/gyro/adis16260.h

+#ifndef SPI_ADIS16260_H_
+#define SPI_ADIS16260_H_
+
+#define ADIS16260_STARTUP_DELAY	220 /* ms */
+
+#define ADIS16260_READ_REG(a)    a
+#define ADIS16260_WRITE_REG(a) ((a) | 0x80)
+
+#define ADIS16260_FLASH_CNT  0x00 /* Flash memory write count */
+#define ADIS16260_SUPPLY_OUT 0x02 /* Power supply measurement */
+#define ADIS16260_GYRO_OUT   0x04 /* X-axis gyroscope output */
+#define ADIS16260_AUX_ADC    0x0A /* analog input channel measurement */
+#define ADIS16260_TEMP_OUT   0x0C /* internal temperature measurement */
+#define ADIS16260_ANGL_OUT   0x0E /* angle displacement */
+#define ADIS16260_GYRO_OFF   0x14 /* Calibration, offset/bias adjustment */
+#define ADIS16260_GYRO_SCALE 0x16 /* Calibration, scale adjustment */
+#define ADIS16260_ALM_MAG1   0x20 /* Alarm 1 magnitude/polarity setting */
+#define ADIS16260_ALM_MAG2   0x22 /* Alarm 2 magnitude/polarity setting */
+#define ADIS16260_ALM_SMPL1  0x24 /* Alarm 1 dynamic rate of change setting */
+#define ADIS16260_ALM_SMPL2  0x26 /* Alarm 2 dynamic rate of change setting */
+#define ADIS16260_ALM_CTRL   0x28 /* Alarm control */
+#define ADIS16260_AUX_DAC    0x30 /* Auxiliary DAC data */
+#define ADIS16260_GPIO_CTRL  0x32 /* Control, digital I/O line */
+#define ADIS16260_MSC_CTRL   0x34 /* Control, data ready, self-test settings */
+#define ADIS16260_SMPL_PRD   0x36 /* Control, internal sample rate */
+#define ADIS16260_SENS_AVG   0x38 /* Control, dynamic range, filtering */
+#define ADIS16260_SLP_CNT    0x3A /* Control, sleep mode initiation */
+#define ADIS16260_DIAG_STAT  0x3C /* Diagnostic, error flags */
+#define ADIS16260_GLOB_CMD   0x3E /* Control, global commands */
+#define ADIS16260_LOT_ID1    0x52 /* Lot Identification Code 1 */
+#define ADIS16260_LOT_ID2    0x54 /* Lot Identification Code 2 */
+#define ADIS16260_PROD_ID    0x56 /* Product identifier;
+				   * convert to decimal = 16,265/16,260 */
+#define ADIS16260_SERIAL_NUM 0x58 /* Serial number */
+
+#define ADIS16260_OUTPUTS    5
+
+#define ADIS16260_ERROR_ACTIVE			(1<<14)
+#define ADIS16260_NEW_DATA			(1<<15)
+
+/* MSC_CTRL */
+#define ADIS16260_MSC_CTRL_MEM_TEST		(1<<11)
+/* Internal self-test enable */
+#define ADIS16260_MSC_CTRL_INT_SELF_TEST	(1<<10)
+#define ADIS16260_MSC_CTRL_NEG_SELF_TEST	(1<<9)
+#define ADIS16260_MSC_CTRL_POS_SELF_TEST	(1<<8)
+#define ADIS16260_MSC_CTRL_DATA_RDY_EN		(1<<2)
+#define ADIS16260_MSC_CTRL_DATA_RDY_POL_HIGH	(1<<1)
+#define ADIS16260_MSC_CTRL_DATA_RDY_DIO2	(1<<0)
+
+/* SMPL_PRD */
+/* Time base (tB): 0 = 1.953 ms, 1 = 60.54 ms */
+#define ADIS16260_SMPL_PRD_TIME_BASE	(1<<7)
+#define ADIS16260_SMPL_PRD_DIV_MASK	0x7F
+
+/* SLP_CNT */
+#define ADIS16260_SLP_CNT_POWER_OFF     0x80
+
+/* DIAG_STAT */
+#define ADIS16260_DIAG_STAT_ALARM2	(1<<9)
+#define ADIS16260_DIAG_STAT_ALARM1	(1<<8)
+#define ADIS16260_DIAG_STAT_FLASH_CHK	(1<<6)
+#define ADIS16260_DIAG_STAT_SELF_TEST	(1<<5)
+#define ADIS16260_DIAG_STAT_OVERFLOW	(1<<4)
+#define ADIS16260_DIAG_STAT_SPI_FAIL	(1<<3)
+#define ADIS16260_DIAG_STAT_FLASH_UPT	(1<<2)
+#define ADIS16260_DIAG_STAT_POWER_HIGH	(1<<1)
+#define ADIS16260_DIAG_STAT_POWER_LOW	(1<<0)
+
+/* GLOB_CMD */
+#define ADIS16260_GLOB_CMD_SW_RESET	(1<<7)
+#define ADIS16260_GLOB_CMD_FLASH_UPD	(1<<3)
+#define ADIS16260_GLOB_CMD_DAC_LATCH	(1<<2)
+#define ADIS16260_GLOB_CMD_FAC_CALIB	(1<<1)
+#define ADIS16260_GLOB_CMD_AUTO_NULL	(1<<0)
+
+#define ADIS16260_MAX_TX 24
+#define ADIS16260_MAX_RX 24
+
+#define ADIS16260_SPI_SLOW	(u32)(300 * 1000)
+#define ADIS16260_SPI_BURST	(u32)(1000 * 1000)
+#define ADIS16260_SPI_FAST	(u32)(2000 * 1000)
+
+/**
+ * struct adis16260_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 adis16260_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 adis16260_set_irq(struct device *dev, bool enable);
+
+#ifdef CONFIG_IIO_RING_BUFFER
+/* At the moment triggers are only used for ring buffer
+ * filling. This may change!
+ */
+
+enum adis16260_scan {
+	ADIS16260_SCAN_SUPPLY,
+	ADIS16260_SCAN_GYRO,
+	ADIS16260_SCAN_AUX_ADC,
+	ADIS16260_SCAN_TEMP,
+	ADIS16260_SCAN_ANGL,
+};
+
+void adis16260_remove_trigger(struct iio_dev *indio_dev);
+int adis16260_probe_trigger(struct iio_dev *indio_dev);
+
+ssize_t adis16260_read_data_from_ring(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf);
+
+
+int adis16260_configure_ring(struct iio_dev *indio_dev);
+void adis16260_unconfigure_ring(struct iio_dev *indio_dev);
+
+int adis16260_initialize_ring(struct iio_ring_buffer *ring);
+void adis16260_uninitialize_ring(struct iio_ring_buffer *ring);
+#else /* CONFIG_IIO_RING_BUFFER */
+
+static inline void adis16260_remove_trigger(struct iio_dev *indio_dev)
+{
+}
+
+static inline int adis16260_probe_trigger(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline ssize_t
+adis16260_read_data_from_ring(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	return 0;
+}
+
+static int adis16260_configure_ring(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline void adis16260_unconfigure_ring(struct iio_dev *indio_dev)
+{
+}
+
+static inline int adis16260_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return 0;
+}
+
+static inline void adis16260_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+}
+
+#endif /* CONFIG_IIO_RING_BUFFER */
+#endif /* SPI_ADIS16260_H_ */

drivers/staging/iio/gyro/adis16260_core.c

+/*
+ * ADIS16260 Programmable Digital Gyroscope Sensor Driver
+ *
+ * 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 "../adc/adc.h"
+#include "gyro.h"
+
+#include "adis16260.h"
+
+#define DRIVER_NAME		"adis16260"
+
+static int adis16260_check_status(struct device *dev);
+
+/**
+ * adis16260_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 adis16260_spi_write_reg_8(struct device *dev,
+		u8 reg_address,
+		u8 val)
+{
+	int ret;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct adis16260_state *st = iio_dev_get_devdata(indio_dev);
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADIS16260_WRITE_REG(reg_address);
+	st->tx[1] = val;
+
+	ret = spi_write(st->us, st->tx, 2);
+	mutex_unlock(&st->buf_lock);
+
+	return ret;
+}
+
+/**
+ * adis16260_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 adis16260_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 adis16260_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 = 20,
+		}, {
+			.tx_buf = st->tx + 2,
+			.bits_per_word = 8,
+			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = 20,
+		},
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADIS16260_WRITE_REG(lower_reg_address);
+	st->tx[1] = value & 0xFF;
+	st->tx[2] = ADIS16260_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;
+}
+
+/**
+ * adis16260_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 adis16260_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 adis16260_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 = 30,
+		}, {
+			.rx_buf = st->rx,
+			.bits_per_word = 8,
+			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = 30,
+		},
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADIS16260_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 adis16260_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 = adis16260_spi_read_reg_16(dev, this_attr->address, (u16 *)&val);
+	if (ret)
+		return ret;
+
+	if (val & ADIS16260_ERROR_ACTIVE)
+		adis16260_check_status(dev);
+	val = ((s16)(val << shift) >> shift);
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t adis16260_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 = adis16260_spi_read_reg_16(dev, this_attr->address, &val);
+	if (ret)
+		return ret;
+
+	if (val & ADIS16260_ERROR_ACTIVE)
+		adis16260_check_status(dev);
+
+	return sprintf(buf, "%u\n", val & 0x0FFF);
+}
+
+static ssize_t adis16260_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 =  adis16260_spi_read_signed(dev, attr, buf, 12);
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static ssize_t adis16260_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 =  adis16260_spi_read_signed(dev, attr, buf, 14);
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static ssize_t adis16260_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 = adis16260_spi_write_reg_16(dev, this_attr->address, val);
+
+error_ret:
+	return ret ? ret : len;
+}
+
+static ssize_t adis16260_read_frequency(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	int ret, len = 0;
+	u16 t;
+	int sps;
+	ret = adis16260_spi_read_reg_16(dev,
+			ADIS16260_SMPL_PRD,
+			&t);
+	if (ret)
+		return ret;
+	sps =  (t & ADIS16260_SMPL_PRD_TIME_BASE) ? 66 : 2048;
+	sps /= (t & ADIS16260_SMPL_PRD_DIV_MASK) + 1;
+	len = sprintf(buf, "%d SPS\n", sps);
+	return len;
+}
+
+static ssize_t adis16260_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 adis16260_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 = (2048 / val);
+	if (t > 0)
+		t--;
+	t &= ADIS16260_SMPL_PRD_DIV_MASK;
+	if ((t & ADIS16260_SMPL_PRD_DIV_MASK) >= 0x0A)
+		st->us->max_speed_hz = ADIS16260_SPI_SLOW;
+	else
+		st->us->max_speed_hz = ADIS16260_SPI_FAST;
+
+	ret = adis16260_spi_write_reg_8(dev,
+			ADIS16260_SMPL_PRD,
+			t);
+
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret ? ret : len;
+}
+
+static int adis16260_reset(struct device *dev)
+{
+	int ret;
+	ret = adis16260_spi_write_reg_8(dev,
+			ADIS16260_GLOB_CMD,
+			ADIS16260_GLOB_CMD_SW_RESET);
+	if (ret)
+		dev_err(dev, "problem resetting device");
+
+	return ret;
+}
+
+static ssize_t adis16260_write_reset(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t len)
+{
+	if (len < 1)
+		return -EINVAL;
+	switch (buf[0]) {
+	case '1':
+	case 'y':
+	case 'Y':
+		return adis16260_reset(dev);
+	}
+	return -EINVAL;
+}
+
+int adis16260_set_irq(struct device *dev, bool enable)
+{
+	int ret;
+	u16 msc;
+	ret = adis16260_spi_read_reg_16(dev, ADIS16260_MSC_CTRL, &msc);
+	if (ret)
+		goto error_ret;
+
+	msc |= ADIS16260_MSC_CTRL_DATA_RDY_POL_HIGH;
+	if (enable)
+		msc |= ADIS16260_MSC_CTRL_DATA_RDY_EN;
+	else
+		msc &= ~ADIS16260_MSC_CTRL_DATA_RDY_EN;
+
+	ret = adis16260_spi_write_reg_16(dev, ADIS16260_MSC_CTRL, msc);
+	if (ret)
+		goto error_ret;
+
+error_ret:
+	return ret;
+}
+
+/* Power down the device */
+static int adis16260_stop_device(struct device *dev)
+{
+	int ret;
+	u16 val = ADIS16260_SLP_CNT_POWER_OFF;
+
+	ret = adis16260_spi_write_reg_16(dev, ADIS16260_SLP_CNT, val);
+	if (ret)
+		dev_err(dev, "problem with turning device off: SLP_CNT");
+
+	return ret;
+}
+
+static int adis16260_self_test(struct device *dev)
+{
+	int ret;
+	ret = adis16260_spi_write_reg_16(dev,
+			ADIS16260_MSC_CTRL,
+			ADIS16260_MSC_CTRL_MEM_TEST);
+	if (ret) {
+		dev_err(dev, "problem starting self test");
+		goto err_ret;
+	}
+
+	adis16260_check_status(dev);
+
+err_ret:
+	return ret;
+}
+
+static int adis16260_check_status(struct device *dev)
+{
+	u16 status;
+	int ret;
+
+	ret = adis16260_spi_read_reg_16(dev, ADIS16260_DIAG_STAT, &status);
+
+	if (ret < 0) {
+		dev_err(dev, "Reading status failed\n");
+		goto error_ret;
+	}
+	ret = status & 0x7F;
+	if (status & ADIS16260_DIAG_STAT_FLASH_CHK)
+		dev_err(dev, "Flash checksum error\n");
+	if (status & ADIS16260_DIAG_STAT_SELF_TEST)
+		dev_err(dev, "Self test error\n");
+	if (status & ADIS16260_DIAG_STAT_OVERFLOW)
+		dev_err(dev, "Sensor overrange\n");
+	if (status & ADIS16260_DIAG_STAT_SPI_FAIL)
+		dev_err(dev, "SPI failure\n");
+	if (status & ADIS16260_DIAG_STAT_FLASH_UPT)
+		dev_err(dev, "Flash update failed\n");
+	if (status & ADIS16260_DIAG_STAT_POWER_HIGH)
+		dev_err(dev, "Power supply above 5.25V\n");
+	if (status & ADIS16260_DIAG_STAT_POWER_LOW)
+		dev_err(dev, "Power supply below 4.75V\n");
+
+error_ret:
+	return ret;
+}
+
+static int adis16260_initial_setup(struct adis16260_state *st)
+{
+	int ret;
+	struct device *dev = &st->indio_dev->dev;
+
+	/* Disable IRQ */
+	ret = adis16260_set_irq(dev, false);
+	if (ret) {
+		dev_err(dev, "disable irq failed");
+		goto err_ret;
+	}
+
+	/* Do self test */
+	ret = adis16260_self_test(dev);
+	if (ret) {
+		dev_err(dev, "self test failure");
+		goto err_ret;
+	}
+
+	/* Read status register to check the result */
+	ret = adis16260_check_status(dev);
+	if (ret) {
+		adis16260_reset(dev);
+		dev_err(dev, "device not playing ball -> reset");
+		msleep(ADIS16260_STARTUP_DELAY);
+		ret = adis16260_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);
+
+err_ret:
+	return ret;
+}
+
+static IIO_DEV_ATTR_IN_NAMED_RAW(supply,
+				adis16260_read_12bit_unsigned,
+				ADIS16260_SUPPLY_OUT);
+static IIO_CONST_ATTR(in_supply_scale, "0.0018315");
+
+static IIO_DEV_ATTR_GYRO(adis16260_read_14bit_signed,
+		ADIS16260_GYRO_OUT);
+static IIO_DEV_ATTR_GYRO_SCALE(S_IWUSR | S_IRUGO,
+		adis16260_read_14bit_signed,
+		adis16260_write_16bit,
+		ADIS16260_GYRO_SCALE);
+static IIO_DEV_ATTR_GYRO_OFFSET(S_IWUSR | S_IRUGO,
+		adis16260_read_12bit_signed,
+		adis16260_write_16bit,
+		ADIS16260_GYRO_OFF);
+
+static IIO_DEV_ATTR_TEMP_RAW(adis16260_read_12bit_unsigned);
+static IIO_CONST_ATTR(temp_offset, "25");
+static IIO_CONST_ATTR(temp_scale, "0.1453");
+
+static IIO_DEV_ATTR_IN_RAW(0, adis16260_read_12bit_unsigned,
+		ADIS16260_AUX_ADC);
+static IIO_CONST_ATTR(in0_scale, "0.0006105");
+
+static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
+		adis16260_read_frequency,
+		adis16260_write_frequency);
+static IIO_DEV_ATTR_ANGL(adis16260_read_14bit_signed,
+		ADIS16260_ANGL_OUT);
+
+static IIO_DEVICE_ATTR(reset, S_IWUSR, NULL, adis16260_write_reset, 0);
+
+static IIO_CONST_ATTR_AVAIL_SAMP_FREQ("256 2048");
+
+static IIO_CONST_ATTR(name, "adis16260");
+
+static struct attribute *adis16260_event_attributes[] = {
+	NULL
+};
+
+static struct attribute_group adis16260_event_attribute_group = {
+	.attrs = adis16260_event_attributes,
+};
+
+static struct attribute *adis16260_attributes[] = {
+	&iio_dev_attr_in_supply_raw.dev_attr.attr,
+	&iio_const_attr_in_supply_scale.dev_attr.attr,
+	&iio_dev_attr_gyro_raw.dev_attr.attr,
+	&iio_dev_attr_gyro_scale.dev_attr.attr,
+	&iio_dev_attr_gyro_offset.dev_attr.attr,
+	&iio_dev_attr_angl_raw.dev_attr.attr,
+	&iio_dev_attr_temp_raw.dev_attr.attr,
+	&iio_const_attr_temp_offset.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 adis16260_attribute_group = {
+	.attrs = adis16260_attributes,
+};
+
+static int __devinit adis16260_probe(struct spi_device *spi)
+{
+	int ret, regdone = 0;
+	struct adis16260_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)*ADIS16260_MAX_RX, GFP_KERNEL);
+	if (st->rx == NULL) {
+		ret = -ENOMEM;
+		goto error_free_st;
+	}
+	st->tx = kzalloc(sizeof(*st->tx)*ADIS16260_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 = &adis16260_event_attribute_group;
+	st->indio_dev->attrs = &adis16260_attribute_group;
+	st->indio_dev->dev_data = (void *)(st);
+	st->indio_dev->driver_module = THIS_MODULE;
+	st->indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = adis16260_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 = adis16260_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,
+				"adis16260");
+		if (ret)
+			goto error_uninitialize_ring;
+
+		ret = adis16260_probe_trigger(st->indio_dev);
+		if (ret)
+			goto error_unregister_line;
+	}
+
+	/* Get the device into a sane initial state */
+	ret = adis16260_initial_setup(st);
+	if (ret)
+		goto error_remove_trigger;
+	return 0;
+
+error_remove_trigger:
+	adis16260_remove_trigger(st->indio_dev);
+error_unregister_line:
+	if (spi->irq)
+		iio_unregister_interrupt_line(st->indio_dev, 0);
+error_uninitialize_ring:
+	adis16260_uninitialize_ring(st->indio_dev->ring);
+error_unreg_ring_funcs:
+	adis16260_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 adis16260_remove(struct spi_device *spi)
+{
+	int ret;
+	struct adis16260_state *st = spi_get_drvdata(spi);
+	struct iio_dev *indio_dev = st->indio_dev;
+
+	ret = adis16260_stop_device(&(indio_dev->dev));
+	if (ret)
+		goto err_ret;
+
+	flush_scheduled_work();
+
+	adis16260_remove_trigger(indio_dev);
+	if (spi->irq)
+		iio_unregister_interrupt_line(indio_dev, 0);
+
+	adis16260_uninitialize_ring(indio_dev->ring);
+	iio_device_unregister(indio_dev);
+	adis16260_unconfigure_ring(indio_dev);
+	kfree(st->tx);
+	kfree(st->rx);
+	kfree(st);
+
+	return 0;
+
+err_ret:
+	return ret;
+}
+
+static struct spi_driver adis16260_driver = {
+	.driver = {
+		.name = "adis16260",
+		.owner = THIS_MODULE,
+	},
+	.probe = adis16260_probe,
+	.remove = __devexit_p(adis16260_remove),
+};
+
+static __init int adis16260_init(void)
+{
+	return spi_register_driver(&adis16260_driver);
+}
+module_init(adis16260_init);
+
+static __exit void adis16260_exit(void)
+{
+	spi_unregister_driver(&adis16260_driver);
+}
+module_exit(adis16260_exit);
+
+MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
+MODULE_DESCRIPTION("Analog Devices ADIS16260/5 Digital Gyroscope Sensor");
+MODULE_LICENSE("GPL v2");

drivers/staging/iio/gyro/adis16260_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 "adis16260.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, ADIS16260_SCAN_SUPPLY, IIO_UNSIGNED(12),
+		ADIS16260_SUPPLY_OUT, NULL);
+static IIO_SCAN_EL_C(gyro, ADIS16260_SCAN_GYRO, IIO_SIGNED(14),
+		ADIS16260_GYRO_OUT, NULL);
+static IIO_SCAN_EL_C(aux_adc, ADIS16260_SCAN_AUX_ADC, IIO_SIGNED(14),
+		ADIS16260_AUX_ADC, NULL);
+static IIO_SCAN_EL_C(temp, ADIS16260_SCAN_TEMP, IIO_UNSIGNED(12),
+		ADIS16260_TEMP_OUT, NULL);
+static IIO_SCAN_EL_C(angl, ADIS16260_SCAN_ANGL, IIO_UNSIGNED(12),
+		ADIS16260_ANGL_OUT, NULL);
+
+static IIO_SCAN_EL_TIMESTAMP(5);
+
+static struct attribute *adis16260_scan_el_attrs[] = {
+	&iio_scan_el_supply.dev_attr.attr,
+	&iio_scan_el_gyro.dev_attr.attr,
+	&iio_scan_el_aux_adc.dev_attr.attr,
+	&iio_scan_el_temp.dev_attr.attr,
+	&iio_scan_el_angl.dev_attr.attr,
+	&iio_scan_el_timestamp.dev_attr.attr,
+	NULL,
+};
+
+static struct attribute_group adis16260_scan_el_group = {
+	.attrs = adis16260_scan_el_attrs,
+	.name = "scan_elements",
+};
+
+/**
+ * adis16260_poll_func_th() top half interrupt handler called by trigger
+ * @private_data:	iio_dev
+ **/
+static void adis16260_poll_func_th(struct iio_dev *indio_dev)
+{
+	struct adis16260_state *st = iio_dev_get_devdata(indio_dev);
+	st->last_timestamp = indio_dev->trig->timestamp;
+	schedule_work(&st->work_trigger_to_ring);
+}
+
+/**
+ * adis16260_read_ring_data() read data registers which will be placed into ring
+ * @dev: device associated with child of actual device (iio_dev or iio_trig)
+ * @rx: somewhere to pass back the value read
+ **/
+static int adis16260_read_ring_data(struct device *dev, u8 *rx)
+{
+	struct spi_message msg;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct adis16260_state *st = iio_dev_get_devdata(indio_dev);
+	struct spi_transfer xfers[ADIS16260_OUTPUTS + 1];
+	int ret;
+	int i;
+
+	mutex_lock(&st->buf_lock);
+
+	spi_message_init(&msg);
+
+	memset(xfers, 0, sizeof(xfers));
+	for (i = 0; i <= ADIS16260_OUTPUTS; i++) {
+		xfers[i].bits_per_word = 8;
+		xfers[i].cs_change = 1;
+		xfers[i].len = 2;
+		xfers[i].delay_usecs = 30;
+		xfers[i].tx_buf = st->tx + 2 * i;
+		if (i < 2) /* SUPPLY_OUT:0x02 GYRO_OUT:0x04 */
+			st->tx[2 * i]
+				= ADIS16260_READ_REG(ADIS16260_SUPPLY_OUT
+						+ 2 * i);
+		else /* 0x06 to 0x09 is reserved */
+			st->tx[2 * i]
+				= ADIS16260_READ_REG(ADIS16260_SUPPLY_OUT
+						+ 2 * i + 4);
+		st->tx[2 * i + 1] = 0;
+		if (i >= 1)
+			xfers[i].rx_buf = rx + 2 * (i - 1);
+		spi_message_add_tail(&xfers[i], &msg);
+	}
+
+	ret = spi_sync(st->us, &msg);
+	if (ret)
+		dev_err(&st->us->dev, "problem when burst reading");
+
+	mutex_unlock(&st->buf_lock);
+
+	return ret;
+}
+
+
+static void adis16260_trigger_bh_to_ring(struct work_struct *work_s)
+{
+	struct adis16260_state *st
+		= container_of(work_s, struct adis16260_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 (adis16260_read_ring_data(&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 adis16260_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 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 adis16260_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 adis16260_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 adis16260_unconfigure_ring(struct iio_dev *indio_dev)
+{
+	kfree(indio_dev->pollfunc);
+	iio_sw_rb_free(indio_dev->ring);
+}
+
+int adis16260_configure_ring(struct iio_dev *indio_dev)
+{
+	int ret = 0;
+	struct adis16260_state *st = indio_dev->dev_data;
+	struct iio_ring_buffer *ring;
+	INIT_WORK(&st->work_trigger_to_ring, adis16260_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.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_aux_adc.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_temp.number);
+	iio_scan_mask_set(indio_dev, iio_scan_el_angl.number);
+	indio_dev->scan_timestamp = true;
+
+	indio_dev->scan_el_attrs = &adis16260_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 = &adis16260_data_rdy_ring_preenable;
+	ring->postenable = &adis16260_data_rdy_ring_postenable;
+	ring->predisable = &adis16260_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 = &adis16260_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 adis16260_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return iio_ring_buffer_register(ring, 0);
+}
+
+void adis16260_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+	iio_ring_buffer_unregister(ring);
+}

drivers/staging/iio/gyro/adis16260_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 "adis16260.h"
+
+/**
+ * adis16260_data_rdy_trig_poll() the event handler for the data rdy trig
+ **/
+static int adis16260_data_rdy_trig_poll(struct iio_dev *dev_info,
+				       int index,
+				       s64 timestamp,
+				       int no_test)
+{
+	struct adis16260_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, &adis16260_data_rdy_trig_poll);
+
+static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
+
+static struct attribute *adis16260_trigger_attrs[] = {
+	&dev_attr_name.attr,
+	NULL,
+};
+
+static const struct attribute_group adis16260_trigger_attr_group = {
+	.attrs = adis16260_trigger_attrs,
+};
+
+/**
+ * adis16260_data_rdy_trigger_set_state() set datardy interrupt state
+ **/
+static int adis16260_data_rdy_trigger_set_state(struct iio_trigger *trig,
+						bool state)
+{
+	struct adis16260_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 = adis16260_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);
+		flush_scheduled_work();
+	} else {
+		iio_add_event_to_list(&iio_event_data_rdy_trig,
+				      &indio_dev->interrupts[0]->ev_list);
+	}
+	return ret;
+}
+
+/**
+ * adis16260_trig_try_reen() try renabling irq for data rdy trigger
+ * @trig:	the datardy trigger
+ **/
+static int adis16260_trig_try_reen(struct iio_trigger *trig)
+{
+	struct adis16260_state *st = trig->private_data;
+	enable_irq(st->us->irq);
+	return 0;
+}
+
+int adis16260_probe_trigger(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct adis16260_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,
+		 "adis16260-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 = &adis16260_data_rdy_trigger_set_state;
+	st->trig->try_reenable = &adis16260_trig_try_reen;
+	st->trig->control_attrs = &adis16260_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 adis16260_remove_trigger(struct iio_dev *indio_dev)
+{
+	struct adis16260_state *state = indio_dev->dev_data;
+
+	iio_trigger_unregister(state->trig);
+	kfree(state->trig->name);
+	iio_free_trigger(state->trig);
+}

drivers/staging/iio/gyro/gyro.h

@@ -39,3 +39,5 @@
 #define IIO_DEV_ATTR_GYRO_Z(_show, _addr)			\
 	IIO_DEVICE_ATTR(gyro_z_raw, S_IRUGO, _show, NULL, _addr)
 
+#define IIO_DEV_ATTR_ANGL(_show, _addr)                         \
+	IIO_DEVICE_ATTR(angl_raw, S_IRUGO, _show, NULL, _addr)