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>

drivers/iio/imu/Kconfig

@@ -25,6 +25,8 @@ config ADIS16480
 	  Say yes here to build support for Analog Devices ADIS16375, ADIS16480,
 	  ADIS16485, ADIS16488 inertial sensors.
 
+source "drivers/iio/imu/bmi160/Kconfig"
+
 config KMX61
 	tristate "Kionix KMX61 6-axis accelerometer and magnetometer"
 	depends on I2C

drivers/iio/imu/Makefile

@@ -13,6 +13,7 @@ adis_lib-$(CONFIG_IIO_ADIS_LIB_BUFFER) += adis_trigger.o
 adis_lib-$(CONFIG_IIO_ADIS_LIB_BUFFER) += adis_buffer.o
 obj-$(CONFIG_IIO_ADIS_LIB) += adis_lib.o
 
+obj-y += bmi160/
 obj-y += inv_mpu6050/
 
 obj-$(CONFIG_KMX61) += kmx61.o

drivers/iio/imu/bmi160/Kconfig

@@ -0,0 +1,32 @@
+#
+# BMI160 IMU driver
+#
+
+config BMI160
+	tristate
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+
+config BMI160_I2C
+	tristate "Bosch BMI160 I2C driver"
+	depends on I2C
+	select BMI160
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for BMI160 IMU on I2C with
+	  accelerometer, gyroscope and external BMG160 magnetometer.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bmi160_i2c.
+
+config BMI160_SPI
+	tristate "Bosch BMI160 SPI driver"
+	depends on SPI
+	select BMI160
+	select REGMAP_SPI
+	help
+	  If you say yes here you get support for BMI160 IMU on SPI with
+	  accelerometer, gyroscope and external BMG160 magnetometer.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bmi160_spi.

drivers/iio/imu/bmi160/Makefile

@@ -0,0 +1,6 @@
+#
+# Makefile for Bosch BMI160 IMU
+#
+obj-$(CONFIG_BMI160) += bmi160_core.o
+obj-$(CONFIG_BMI160_I2C) += bmi160_i2c.o
+obj-$(CONFIG_BMI160_SPI) += bmi160_spi.o

drivers/iio/imu/bmi160/bmi160.h

@@ -0,0 +1,10 @@
+#ifndef BMI160_H_
+#define BMI160_H_
+
+extern const struct regmap_config bmi160_regmap_config;
+
+int bmi160_core_probe(struct device *dev, struct regmap *regmap,
+		      const char *name, bool use_spi);
+void bmi160_core_remove(struct device *dev);
+
+#endif  /* BMI160_H_ */

drivers/iio/imu/bmi160/bmi160_i2c.c

@@ -0,0 +1,72 @@
+/*
+ * BMI160 - Bosch IMU, I2C bits
+ *
+ * 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.
+ *
+ * 7-bit I2C slave address is:
+ *      - 0x68 if SDO is pulled to GND
+ *      - 0x69 if SDO is pulled to VDDIO
+ */
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <linux/acpi.h>
+
+#include "bmi160.h"
+
+static int bmi160_i2c_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct regmap *regmap;
+	const char *name = NULL;
+
+	regmap = devm_regmap_init_i2c(client, &bmi160_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "Failed to register i2c regmap %d\n",
+			(int)PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	if (id)
+		name = id->name;
+
+	return bmi160_core_probe(&client->dev, regmap, name, false);
+}
+
+static int bmi160_i2c_remove(struct i2c_client *client)
+{
+	bmi160_core_remove(&client->dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id bmi160_i2c_id[] = {
+	{"bmi160", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, bmi160_i2c_id);
+
+static const struct acpi_device_id bmi160_acpi_match[] = {
+	{"BMI0160", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, bmi160_acpi_match);
+
+static struct i2c_driver bmi160_i2c_driver = {
+	.driver = {
+		.name			= "bmi160_i2c",
+		.acpi_match_table	= ACPI_PTR(bmi160_acpi_match),
+	},
+	.probe		= bmi160_i2c_probe,
+	.remove		= bmi160_i2c_remove,
+	.id_table	= bmi160_i2c_id,
+};
+module_i2c_driver(bmi160_i2c_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
+MODULE_DESCRIPTION("BMI160 I2C driver");
+MODULE_LICENSE("GPL v2");

drivers/iio/imu/bmi160/bmi160_spi.c

@@ -0,0 +1,63 @@
+/*
+ * BMI160 - Bosch IMU, SPI bits
+ *
+ * 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.
+ */
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/regmap.h>
+#include <linux/acpi.h>
+
+#include "bmi160.h"
+
+static int bmi160_spi_probe(struct spi_device *spi)
+{
+	struct regmap *regmap;
+	const struct spi_device_id *id = spi_get_device_id(spi);
+
+	regmap = devm_regmap_init_spi(spi, &bmi160_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&spi->dev, "Failed to register spi regmap %d\n",
+			(int)PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+	return bmi160_core_probe(&spi->dev, regmap, id->name, true);
+}
+
+static int bmi160_spi_remove(struct spi_device *spi)
+{
+	bmi160_core_remove(&spi->dev);
+
+	return 0;
+}
+
+static const struct spi_device_id bmi160_spi_id[] = {
+	{"bmi160", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, bmi160_spi_id);
+
+static const struct acpi_device_id bmi160_acpi_match[] = {
+	{"BMI0160", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, bmi160_acpi_match);
+
+static struct spi_driver bmi160_spi_driver = {
+	.probe		= bmi160_spi_probe,
+	.remove		= bmi160_spi_remove,
+	.id_table	= bmi160_spi_id,
+	.driver = {
+		.acpi_match_table = ACPI_PTR(bmi160_acpi_match),
+		.name	= "bmi160_spi",
+	},
+};
+module_spi_driver(bmi160_spi_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com");
+MODULE_DESCRIPTION("Bosch BMI160 SPI driver");
+MODULE_LICENSE("GPL v2");