iio: imu: Add initial support for Bosch BMI160

BMI160 is an Inertial Measurement Unit (IMU) which provides acceleration
and angular rate measurement. It also offers a secondary I2C interface
for connecting a magnetometer sensor (usually BMM160).

Current driver offers support for accelerometer and gyroscope readings
via sysfs or via buffer interface using an external trigger (e.g.
hrtimer). Data is retrieved from IMU via I2C or SPI interface.

Datasheet is at:
	http://www.mouser.com/ds/2/783/BST-BMI160-DS000-07-786474.pdf

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 596 insertions, 0 deletions

diff --git a/drivers/iio/imu/bmi160/bmi160_core.c b/drivers/iio/imu/bmi160/bmi160_core.c
new file mode 100644
index 0000000..0bf92b0
--- /dev/null
+++ b/drivers/iio/imu/bmi160/bmi160_core.c
@@ -0,0 +1,596 @@
+/*
+ * BMI160 - Bosch IMU (accel, gyro plus external magnetometer)
+ *
+ * Copyright (c) 2016, Intel Corporation.
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * IIO core driver for BMI160, with support for I2C/SPI busses
+ *
+ * TODO: magnetometer, interrupts, hardware FIFO
+ */
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/acpi.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/buffer.h>
+
+#include "bmi160.h"
+
+#define BMI160_REG_CHIP_ID	0x00
+#define BMI160_CHIP_ID_VAL	0xD1
+
+#define BMI160_REG_PMU_STATUS	0x03
+
+/* X axis data low byte address, the rest can be obtained using axis offset */
+#define BMI160_REG_DATA_MAGN_XOUT_L	0x04
+#define BMI160_REG_DATA_GYRO_XOUT_L	0x0C
+#define BMI160_REG_DATA_ACCEL_XOUT_L	0x12
+
+#define BMI160_REG_ACCEL_CONFIG		0x40
+#define BMI160_ACCEL_CONFIG_ODR_MASK	GENMASK(3, 0)
+#define BMI160_ACCEL_CONFIG_BWP_MASK	GENMASK(6, 4)
+
+#define BMI160_REG_ACCEL_RANGE		0x41
+#define BMI160_ACCEL_RANGE_2G		0x03
+#define BMI160_ACCEL_RANGE_4G		0x05
+#define BMI160_ACCEL_RANGE_8G		0x08
+#define BMI160_ACCEL_RANGE_16G		0x0C
+
+#define BMI160_REG_GYRO_CONFIG		0x42
+#define BMI160_GYRO_CONFIG_ODR_MASK	GENMASK(3, 0)
+#define BMI160_GYRO_CONFIG_BWP_MASK	GENMASK(5, 4)
+
+#define BMI160_REG_GYRO_RANGE		0x43
+#define BMI160_GYRO_RANGE_2000DPS	0x00
+#define BMI160_GYRO_RANGE_1000DPS	0x01
+#define BMI160_GYRO_RANGE_500DPS	0x02
+#define BMI160_GYRO_RANGE_250DPS	0x03
+#define BMI160_GYRO_RANGE_125DPS	0x04
+
+#define BMI160_REG_CMD			0x7E
+#define BMI160_CMD_ACCEL_PM_SUSPEND	0x10
+#define BMI160_CMD_ACCEL_PM_NORMAL	0x11
+#define BMI160_CMD_ACCEL_PM_LOW_POWER	0x12
+#define BMI160_CMD_GYRO_PM_SUSPEND	0x14
+#define BMI160_CMD_GYRO_PM_NORMAL	0x15
+#define BMI160_CMD_GYRO_PM_FAST_STARTUP	0x17
+#define BMI160_CMD_SOFTRESET		0xB6
+
+#define BMI160_REG_DUMMY		0x7F
+
+#define BMI160_ACCEL_PMU_MIN_USLEEP	3200
+#define BMI160_ACCEL_PMU_MAX_USLEEP	3800
+#define BMI160_GYRO_PMU_MIN_USLEEP	55000
+#define BMI160_GYRO_PMU_MAX_USLEEP	80000
+#define BMI160_SOFTRESET_USLEEP		1000
+
+#define BMI160_CHANNEL(_type, _axis, _index) {			\
+	.type = _type,						\
+	.modified = 1,						\
+	.channel2 = IIO_MOD_##_axis,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
+		BIT(IIO_CHAN_INFO_SAMP_FREQ),			\
+	.scan_index = _index,					\
+	.scan_type = {						\
+		.sign = 's',					\
+		.realbits = 16,					\
+		.storagebits = 16,				\
+		.endianness = IIO_LE,				\
+	},							\
+}
+
+/* scan indexes follow DATA register order */
+enum bmi160_scan_axis {
+	BMI160_SCAN_EXT_MAGN_X = 0,
+	BMI160_SCAN_EXT_MAGN_Y,
+	BMI160_SCAN_EXT_MAGN_Z,
+	BMI160_SCAN_RHALL,
+	BMI160_SCAN_GYRO_X,
+	BMI160_SCAN_GYRO_Y,
+	BMI160_SCAN_GYRO_Z,
+	BMI160_SCAN_ACCEL_X,
+	BMI160_SCAN_ACCEL_Y,
+	BMI160_SCAN_ACCEL_Z,
+	BMI160_SCAN_TIMESTAMP,
+};
+
+enum bmi160_sensor_type {
+	BMI160_ACCEL	= 0,
+	BMI160_GYRO,
+	BMI160_EXT_MAGN,
+	BMI160_NUM_SENSORS /* must be last */
+};
+
+struct bmi160_data {
+	struct regmap *regmap;
+};
+
+const struct regmap_config bmi160_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+EXPORT_SYMBOL(bmi160_regmap_config);
+
+struct bmi160_regs {
+	u8 data; /* LSB byte register for X-axis */
+	u8 config;
+	u8 config_odr_mask;
+	u8 config_bwp_mask;
+	u8 range;
+	u8 pmu_cmd_normal;
+	u8 pmu_cmd_suspend;
+};
+
+static struct bmi160_regs bmi160_regs[] = {
+	[BMI160_ACCEL] = {
+		.data	= BMI160_REG_DATA_ACCEL_XOUT_L,
+		.config	= BMI160_REG_ACCEL_CONFIG,
+		.config_odr_mask = BMI160_ACCEL_CONFIG_ODR_MASK,
+		.config_bwp_mask = BMI160_ACCEL_CONFIG_BWP_MASK,
+		.range	= BMI160_REG_ACCEL_RANGE,
+		.pmu_cmd_normal = BMI160_CMD_ACCEL_PM_NORMAL,
+		.pmu_cmd_suspend = BMI160_CMD_ACCEL_PM_SUSPEND,
+	},
+	[BMI160_GYRO] = {
+		.data	= BMI160_REG_DATA_GYRO_XOUT_L,
+		.config	= BMI160_REG_GYRO_CONFIG,
+		.config_odr_mask = BMI160_GYRO_CONFIG_ODR_MASK,
+		.config_bwp_mask = BMI160_GYRO_CONFIG_BWP_MASK,
+		.range	= BMI160_REG_GYRO_RANGE,
+		.pmu_cmd_normal = BMI160_CMD_GYRO_PM_NORMAL,
+		.pmu_cmd_suspend = BMI160_CMD_GYRO_PM_SUSPEND,
+	},
+};
+
+struct bmi160_pmu_time {
+	unsigned long min;
+	unsigned long max;
+};
+
+static struct bmi160_pmu_time bmi160_pmu_time[] = {
+	[BMI160_ACCEL] = {
+		.min = BMI160_ACCEL_PMU_MIN_USLEEP,
+		.max = BMI160_ACCEL_PMU_MAX_USLEEP
+	},
+	[BMI160_GYRO] = {
+		.min = BMI160_GYRO_PMU_MIN_USLEEP,
+		.max = BMI160_GYRO_PMU_MIN_USLEEP,
+	},
+};
+
+struct bmi160_scale {
+	u8 bits;
+	int uscale;
+};
+
+struct bmi160_odr {
+	u8 bits;
+	int odr;
+	int uodr;
+};
+
+static const struct bmi160_scale bmi160_accel_scale[] = {
+	{ BMI160_ACCEL_RANGE_2G, 598},
+	{ BMI160_ACCEL_RANGE_4G, 1197},
+	{ BMI160_ACCEL_RANGE_8G, 2394},
+	{ BMI160_ACCEL_RANGE_16G, 4788},
+};
+
+static const struct bmi160_scale bmi160_gyro_scale[] = {
+	{ BMI160_GYRO_RANGE_2000DPS, 1065},
+	{ BMI160_GYRO_RANGE_1000DPS, 532},
+	{ BMI160_GYRO_RANGE_500DPS, 266},
+	{ BMI160_GYRO_RANGE_250DPS, 133},
+	{ BMI160_GYRO_RANGE_125DPS, 66},
+};
+
+struct bmi160_scale_item {
+	const struct bmi160_scale *tbl;
+	int num;
+};
+
+static const struct  bmi160_scale_item bmi160_scale_table[] = {
+	[BMI160_ACCEL] = {
+		.tbl	= bmi160_accel_scale,
+		.num	= ARRAY_SIZE(bmi160_accel_scale),
+	},
+	[BMI160_GYRO] = {
+		.tbl	= bmi160_gyro_scale,
+		.num	= ARRAY_SIZE(bmi160_gyro_scale),
+	},
+};
+
+static const struct bmi160_odr bmi160_accel_odr[] = {
+	{0x01, 0, 78125},
+	{0x02, 1, 5625},
+	{0x03, 3, 125},
+	{0x04, 6, 25},
+	{0x05, 12, 5},
+	{0x06, 25, 0},
+	{0x07, 50, 0},
+	{0x08, 100, 0},
+	{0x09, 200, 0},
+	{0x0A, 400, 0},
+	{0x0B, 800, 0},
+	{0x0C, 1600, 0},
+};
+
+static const struct bmi160_odr bmi160_gyro_odr[] = {
+	{0x06, 25, 0},
+	{0x07, 50, 0},
+	{0x08, 100, 0},
+	{0x09, 200, 0},
+	{0x0A, 400, 0},
+	{0x0B, 8000, 0},
+	{0x0C, 1600, 0},
+	{0x0D, 3200, 0},
+};
+
+struct bmi160_odr_item {
+	const struct bmi160_odr *tbl;
+	int num;
+};
+
+static const struct  bmi160_odr_item bmi160_odr_table[] = {
+	[BMI160_ACCEL] = {
+		.tbl	= bmi160_accel_odr,
+		.num	= ARRAY_SIZE(bmi160_accel_odr),
+	},
+	[BMI160_GYRO] = {
+		.tbl	= bmi160_gyro_odr,
+		.num	= ARRAY_SIZE(bmi160_gyro_odr),
+	},
+};
+
+static const struct iio_chan_spec bmi160_channels[] = {
+	BMI160_CHANNEL(IIO_ACCEL, X, BMI160_SCAN_ACCEL_X),
+	BMI160_CHANNEL(IIO_ACCEL, Y, BMI160_SCAN_ACCEL_Y),
+	BMI160_CHANNEL(IIO_ACCEL, Z, BMI160_SCAN_ACCEL_Z),
+	BMI160_CHANNEL(IIO_ANGL_VEL, X, BMI160_SCAN_GYRO_X),
+	BMI160_CHANNEL(IIO_ANGL_VEL, Y, BMI160_SCAN_GYRO_Y),
+	BMI160_CHANNEL(IIO_ANGL_VEL, Z, BMI160_SCAN_GYRO_Z),
+	IIO_CHAN_SOFT_TIMESTAMP(BMI160_SCAN_TIMESTAMP),
+};
+
+static enum bmi160_sensor_type bmi160_to_sensor(enum iio_chan_type iio_type)
+{
+	switch (iio_type) {
+	case IIO_ACCEL:
+		return BMI160_ACCEL;
+	case IIO_ANGL_VEL:
+		return BMI160_GYRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static
+int bmi160_set_mode(struct bmi160_data *data, enum bmi160_sensor_type t,
+		    bool mode)
+{
+	int ret;
+	u8 cmd;
+
+	if (mode)
+		cmd = bmi160_regs[t].pmu_cmd_normal;
+	else
+		cmd = bmi160_regs[t].pmu_cmd_suspend;
+
+	ret = regmap_write(data->regmap, BMI160_REG_CMD, cmd);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(bmi160_pmu_time[t].min, bmi160_pmu_time[t].max);
+
+	return 0;
+}
+
+static
+int bmi160_set_scale(struct bmi160_data *data, enum bmi160_sensor_type t,
+		     int uscale)
+{
+	int i;
+
+	for (i = 0; i < bmi160_scale_table[t].num; i++)
+		if (bmi160_scale_table[t].tbl[i].uscale == uscale)
+			break;
+
+	if (i == bmi160_scale_table[t].num)
+		return -EINVAL;
+
+	return regmap_write(data->regmap, bmi160_regs[t].range,
+			    bmi160_scale_table[t].tbl[i].bits);
+}
+
+static
+int bmi160_get_scale(struct bmi160_data *data, enum bmi160_sensor_type t,
+		     int *uscale)
+{
+	int i, ret, val;
+
+	ret = regmap_read(data->regmap, bmi160_regs[t].range, &val);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < bmi160_scale_table[t].num; i++)
+		if (bmi160_scale_table[t].tbl[i].bits == val) {
+			*uscale = bmi160_scale_table[t].tbl[i].uscale;
+			return 0;
+		}
+
+	return -EINVAL;
+}
+
+static int bmi160_get_data(struct bmi160_data *data, int chan_type,
+			   int axis, int *val)
+{
+	u8 reg;
+	int ret;
+	__le16 sample;
+	enum bmi160_sensor_type t = bmi160_to_sensor(chan_type);
+
+	reg = bmi160_regs[t].data + (axis - IIO_MOD_X) * sizeof(__le16);
+
+	ret = regmap_bulk_read(data->regmap, reg, &sample, sizeof(__le16));
+	if (ret < 0)
+		return ret;
+
+	*val = sign_extend32(le16_to_cpu(sample), 15);
+
+	return 0;
+}
+
+static
+int bmi160_set_odr(struct bmi160_data *data, enum bmi160_sensor_type t,
+		   int odr, int uodr)
+{
+	int i;
+
+	for (i = 0; i < bmi160_odr_table[t].num; i++)
+		if (bmi160_odr_table[t].tbl[i].odr == odr &&
+		    bmi160_odr_table[t].tbl[i].uodr == uodr)
+			break;
+
+	if (i >= bmi160_odr_table[t].num)
+		return -EINVAL;
+
+	return regmap_update_bits(data->regmap,
+				  bmi160_regs[t].config,
+				  bmi160_odr_table[t].tbl[i].bits,
+				  bmi160_regs[t].config_odr_mask);
+}
+
+static int bmi160_get_odr(struct bmi160_data *data, enum bmi160_sensor_type t,
+			  int *odr, int *uodr)
+{
+	int i, val, ret;
+
+	ret = regmap_read(data->regmap, bmi160_regs[t].config, &val);
+	if (ret < 0)
+		return ret;
+
+	val &= bmi160_regs[t].config_odr_mask;
+
+	for (i = 0; i < bmi160_odr_table[t].num; i++)
+		if (val == bmi160_odr_table[t].tbl[i].bits)
+			break;
+
+	if (i >= bmi160_odr_table[t].num)
+		return -EINVAL;
+
+	*odr = bmi160_odr_table[t].tbl[i].odr;
+	*uodr = bmi160_odr_table[t].tbl[i].uodr;
+
+	return 0;
+}
+
+static irqreturn_t bmi160_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct bmi160_data *data = iio_priv(indio_dev);
+	s16 buf[16]; /* 3 sens x 3 axis x s16 + 3 x s16 pad + 4 x s16 tstamp */
+	int i, ret, j = 0, base = BMI160_REG_DATA_MAGN_XOUT_L;
+	__le16 sample;
+
+	for_each_set_bit(i, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		ret = regmap_bulk_read(data->regmap, base + i * sizeof(__le16),
+				       &sample, sizeof(__le16));
+		if (ret < 0)
+			goto done;
+		buf[j++] = sample;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
+done:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+
+static int bmi160_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long mask)
+{
+	int ret;
+	struct bmi160_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = bmi160_get_data(data, chan->type, chan->channel2, val);
+		if (ret < 0)
+			return ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		ret = bmi160_get_scale(data,
+				       bmi160_to_sensor(chan->type), val2);
+		return ret < 0 ? ret : IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = bmi160_get_odr(data, bmi160_to_sensor(chan->type),
+				     val, val2);
+		return ret < 0 ? ret : IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int bmi160_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val, int val2, long mask)
+{
+	struct bmi160_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		return bmi160_set_scale(data,
+					bmi160_to_sensor(chan->type), val2);
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return bmi160_set_odr(data, bmi160_to_sensor(chan->type),
+				      val, val2);
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct iio_info bmi160_info = {
+	.driver_module = THIS_MODULE,
+	.read_raw = bmi160_read_raw,
+	.write_raw = bmi160_write_raw,
+};
+
+static const char *bmi160_match_acpi_device(struct device *dev)
+{
+	const struct acpi_device_id *id;
+
+	id = acpi_match_device(dev->driver->acpi_match_table, dev);
+	if (!id)
+		return NULL;
+
+	return dev_name(dev);
+}
+
+static int bmi160_chip_init(struct bmi160_data *data, bool use_spi)
+{
+	int ret;
+	unsigned int val;
+	struct device *dev = regmap_get_device(data->regmap);
+
+	ret = regmap_write(data->regmap, BMI160_REG_CMD, BMI160_CMD_SOFTRESET);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(BMI160_SOFTRESET_USLEEP, BMI160_SOFTRESET_USLEEP + 1);
+
+	/*
+	 * CS rising edge is needed before starting SPI, so do a dummy read
+	 * See Section 3.2.1, page 86 of the datasheet
+	 */
+	if (use_spi) {
+		ret = regmap_read(data->regmap, BMI160_REG_DUMMY, &val);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = regmap_read(data->regmap, BMI160_REG_CHIP_ID, &val);
+	if (ret < 0) {
+		dev_err(dev, "Error reading chip id\n");
+		return ret;
+	}
+	if (val != BMI160_CHIP_ID_VAL) {
+		dev_err(dev, "Wrong chip id, got %x expected %x\n",
+			val, BMI160_CHIP_ID_VAL);
+		return -ENODEV;
+	}
+
+	ret = bmi160_set_mode(data, BMI160_ACCEL, true);
+	if (ret < 0)
+		return ret;
+
+	ret = bmi160_set_mode(data, BMI160_GYRO, true);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static void bmi160_chip_uninit(struct bmi160_data *data)
+{
+	bmi160_set_mode(data, BMI160_GYRO, false);
+	bmi160_set_mode(data, BMI160_ACCEL, false);
+}
+
+int bmi160_core_probe(struct device *dev, struct regmap *regmap,
+		      const char *name, bool use_spi)
+{
+	struct iio_dev *indio_dev;
+	struct bmi160_data *data;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	dev_set_drvdata(dev, indio_dev);
+	data->regmap = regmap;
+
+	ret = bmi160_chip_init(data, use_spi);
+	if (ret < 0)
+		return ret;
+
+	if (!name && ACPI_HANDLE(dev))
+		name = bmi160_match_acpi_device(dev);
+
+	indio_dev->dev.parent = dev;
+	indio_dev->channels = bmi160_channels;
+	indio_dev->num_channels = ARRAY_SIZE(bmi160_channels);
+	indio_dev->name = name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &bmi160_info;
+
+	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+					 bmi160_trigger_handler, NULL);
+	if (ret < 0)
+		goto uninit;
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0)
+		goto buffer_cleanup;
+
+	return 0;
+buffer_cleanup:
+	iio_triggered_buffer_cleanup(indio_dev);
+uninit:
+	bmi160_chip_uninit(data);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(bmi160_core_probe);
+
+void bmi160_core_remove(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct bmi160_data *data = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+	bmi160_chip_uninit(data);
+}
+EXPORT_SYMBOL_GPL(bmi160_core_remove);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com");
+MODULE_DESCRIPTION("Bosch BMI160 driver");
+MODULE_LICENSE("GPL v2");