iio: imu: Add i2c driver for bmi270 imu

Add initial i2c support for the Bosch BMI270 6-axis IMU.
Provides raw read access to acceleration and angle velocity measurements
via iio channels. Device configuration requires firmware provided by
Bosch and is requested and load from userspace.

Signed-off-by: Alex Lanzano <lanzano.alex@gmail.com>
Link: https://patch.msgid.link/20240912210749.3080157-3-lanzano.alex@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -4035,6 +4035,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/accel/bosch,bma400.yaml
 F:	drivers/iio/accel/bma400*
 
+BOSCH SENSORTEC BMI270 IMU IIO DRIVER
+M:	Alex Lanzano <lanzano.alex@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/imu/bosch,bmi270.yaml
+F:	drivers/iio/imu/bmi270/
+
 BOSCH SENSORTEC BMI323 IMU IIO DRIVER
 M:	Jagath Jog J <jagathjog1996@gmail.com>
 L:	linux-iio@vger.kernel.org

drivers/iio/imu/Kconfig

@@ -53,6 +53,7 @@ config ADIS16480
 	  ADIS16485, ADIS16488 inertial sensors.
 
 source "drivers/iio/imu/bmi160/Kconfig"
+source "drivers/iio/imu/bmi270/Kconfig"
 source "drivers/iio/imu/bmi323/Kconfig"
 source "drivers/iio/imu/bno055/Kconfig"
 

drivers/iio/imu/Makefile

@@ -15,6 +15,7 @@ adis_lib-$(CONFIG_IIO_ADIS_LIB_BUFFER) += adis_buffer.o
 obj-$(CONFIG_IIO_ADIS_LIB) += adis_lib.o
 
 obj-y += bmi160/
+obj-y += bmi270/
 obj-y += bmi323/
 obj-y += bno055/
 

drivers/iio/imu/bmi270/Kconfig

@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# BMI270 IMU driver
+#
+
+config BMI270
+	tristate
+	select IIO_BUFFER
+
+config BMI270_I2C
+	tristate "Bosch BMI270 I2C driver"
+	depends on I2C
+	select BMI270
+	select REGMAP_I2C
+	help
+	  Enable support for the Bosch BMI270 6-Axis IMU connected to I2C
+	  interface.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bmi270_i2c.

drivers/iio/imu/bmi270/Makefile

@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for Bosch BMI270 IMU
+#
+obj-$(CONFIG_BMI270) += bmi270_core.o
+obj-$(CONFIG_BMI270_I2C) += bmi270_i2c.o

drivers/iio/imu/bmi270/bmi270.h

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+
+#ifndef BMI270_H_
+#define BMI270_H_
+
+#include <linux/regmap.h>
+
+struct device;
+struct bmi270_data {
+	struct device *dev;
+	struct regmap *regmap;
+};
+
+extern const struct regmap_config bmi270_regmap_config;
+
+int bmi270_core_probe(struct device *dev, struct regmap *regmap);
+
+#endif  /* BMI270_H_ */

drivers/iio/imu/bmi270/bmi270_core.c

@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+#include <linux/bitfield.h>
+#include <linux/firmware.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include <linux/iio/iio.h>
+
+#include "bmi270.h"
+
+#define BMI270_CHIP_ID_REG				0x00
+#define BMI270_CHIP_ID_VAL				0x24
+#define BMI270_CHIP_ID_MSK				GENMASK(7, 0)
+
+#define BMI270_ACCEL_X_REG				0x0c
+#define BMI270_ANG_VEL_X_REG				0x12
+
+#define BMI270_INTERNAL_STATUS_REG			0x21
+#define BMI270_INTERNAL_STATUS_MSG_MSK			GENMASK(3, 0)
+#define BMI270_INTERNAL_STATUS_MSG_INIT_OK		0x01
+
+#define BMI270_INTERNAL_STATUS_AXES_REMAP_ERR_MSK	BIT(5)
+#define BMI270_INTERNAL_STATUS_ODR_50HZ_ERR_MSK		BIT(6)
+
+#define BMI270_ACC_CONF_REG				0x40
+#define BMI270_ACC_CONF_ODR_MSK				GENMASK(3, 0)
+#define BMI270_ACC_CONF_ODR_100HZ			0x08
+#define BMI270_ACC_CONF_BWP_MSK				GENMASK(6, 4)
+#define BMI270_ACC_CONF_BWP_NORMAL_MODE			0x02
+#define BMI270_ACC_CONF_FILTER_PERF_MSK			BIT(7)
+
+#define BMI270_GYR_CONF_REG				0x42
+#define BMI270_GYR_CONF_ODR_MSK				GENMASK(3, 0)
+#define BMI270_GYR_CONF_ODR_200HZ			0x09
+#define BMI270_GYR_CONF_BWP_MSK				GENMASK(5, 4)
+#define BMI270_GYR_CONF_BWP_NORMAL_MODE			0x02
+#define BMI270_GYR_CONF_NOISE_PERF_MSK			BIT(6)
+#define BMI270_GYR_CONF_FILTER_PERF_MSK			BIT(7)
+
+#define BMI270_INIT_CTRL_REG				0x59
+#define BMI270_INIT_CTRL_LOAD_DONE_MSK			BIT(0)
+
+#define BMI270_INIT_DATA_REG				0x5e
+
+#define BMI270_PWR_CONF_REG				0x7c
+#define BMI270_PWR_CONF_ADV_PWR_SAVE_MSK		BIT(0)
+#define BMI270_PWR_CONF_FIFO_WKUP_MSK			BIT(1)
+#define BMI270_PWR_CONF_FUP_EN_MSK			BIT(2)
+
+#define BMI270_PWR_CTRL_REG				0x7d
+#define BMI270_PWR_CTRL_AUX_EN_MSK			BIT(0)
+#define BMI270_PWR_CTRL_GYR_EN_MSK			BIT(1)
+#define BMI270_PWR_CTRL_ACCEL_EN_MSK			BIT(2)
+#define BMI270_PWR_CTRL_TEMP_EN_MSK			BIT(3)
+
+#define BMI270_INIT_DATA_FILE "bmi270-init-data.fw"
+
+enum bmi270_scan {
+	BMI270_SCAN_ACCEL_X,
+	BMI270_SCAN_ACCEL_Y,
+	BMI270_SCAN_ACCEL_Z,
+	BMI270_SCAN_GYRO_X,
+	BMI270_SCAN_GYRO_Y,
+	BMI270_SCAN_GYRO_Z,
+};
+
+const struct regmap_config bmi270_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+EXPORT_SYMBOL_NS_GPL(bmi270_regmap_config, IIO_BMI270);
+
+static int bmi270_get_data(struct bmi270_data *bmi270_device,
+			   int chan_type, int axis, int *val)
+{
+	__le16 sample;
+	int reg;
+	int ret;
+
+	switch (chan_type) {
+	case IIO_ACCEL:
+		reg = BMI270_ACCEL_X_REG + (axis - IIO_MOD_X) * 2;
+		break;
+	case IIO_ANGL_VEL:
+		reg = BMI270_ANG_VEL_X_REG + (axis - IIO_MOD_X) * 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = regmap_bulk_read(bmi270_device->regmap, reg, &sample, sizeof(sample));
+	if (ret)
+		return ret;
+
+	*val = sign_extend32(le16_to_cpu(sample), 15);
+
+	return 0;
+}
+
+static int bmi270_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long mask)
+{
+	int ret;
+	struct bmi270_data *bmi270_device = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = bmi270_get_data(bmi270_device, chan->type, chan->channel2, val);
+		if (ret)
+			return ret;
+
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info bmi270_info = {
+	.read_raw = bmi270_read_raw,
+};
+
+#define BMI270_ACCEL_CHANNEL(_axis) {				\
+	.type = IIO_ACCEL,					\
+	.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_FREQUENCY),			\
+}
+
+#define BMI270_ANG_VEL_CHANNEL(_axis) {				\
+	.type = IIO_ANGL_VEL,					\
+	.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_FREQUENCY),			\
+}
+
+static const struct iio_chan_spec bmi270_channels[] = {
+	BMI270_ACCEL_CHANNEL(X),
+	BMI270_ACCEL_CHANNEL(Y),
+	BMI270_ACCEL_CHANNEL(Z),
+	BMI270_ANG_VEL_CHANNEL(X),
+	BMI270_ANG_VEL_CHANNEL(Y),
+	BMI270_ANG_VEL_CHANNEL(Z),
+};
+
+static int bmi270_validate_chip_id(struct bmi270_data *bmi270_device)
+{
+	int chip_id;
+	int ret;
+	struct device *dev = bmi270_device->dev;
+	struct regmap *regmap = bmi270_device->regmap;
+
+	ret = regmap_read(regmap, BMI270_CHIP_ID_REG, &chip_id);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to read chip id");
+
+	if (chip_id != BMI270_CHIP_ID_VAL)
+		dev_info(dev, "Unknown chip id 0x%x", chip_id);
+
+	return 0;
+}
+
+static int bmi270_write_calibration_data(struct bmi270_data *bmi270_device)
+{
+	int ret;
+	int status = 0;
+	const struct firmware *init_data;
+	struct device *dev = bmi270_device->dev;
+	struct regmap *regmap = bmi270_device->regmap;
+
+	ret = regmap_clear_bits(regmap, BMI270_PWR_CONF_REG,
+				BMI270_PWR_CONF_ADV_PWR_SAVE_MSK);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to write power configuration");
+
+	/*
+	 * After disabling advanced power save, all registers are accessible
+	 * after a 450us delay. This delay is specified in table A of the
+	 * datasheet.
+	 */
+	usleep_range(450, 1000);
+
+	ret = regmap_clear_bits(regmap, BMI270_INIT_CTRL_REG,
+				BMI270_INIT_CTRL_LOAD_DONE_MSK);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to prepare device to load init data");
+
+	ret = request_firmware(&init_data, BMI270_INIT_DATA_FILE, dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to load init data file");
+
+	ret = regmap_bulk_write(regmap, BMI270_INIT_DATA_REG,
+				init_data->data, init_data->size);
+	release_firmware(init_data);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to write init data");
+
+	ret = regmap_set_bits(regmap, BMI270_INIT_CTRL_REG,
+			      BMI270_INIT_CTRL_LOAD_DONE_MSK);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to stop device initialization");
+
+	/*
+	 * Wait at least 140ms for the device to complete configuration.
+	 * This delay is specified in table C of the datasheet.
+	 */
+	usleep_range(140000, 160000);
+
+	ret = regmap_read(regmap, BMI270_INTERNAL_STATUS_REG, &status);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to read internal status");
+
+	if (status != BMI270_INTERNAL_STATUS_MSG_INIT_OK)
+		return dev_err_probe(dev, -ENODEV, "Device failed to initialize");
+
+	return 0;
+}
+
+static int bmi270_configure_imu(struct bmi270_data *bmi270_device)
+{
+	int ret;
+	struct device *dev = bmi270_device->dev;
+	struct regmap *regmap = bmi270_device->regmap;
+
+	ret = regmap_set_bits(regmap, BMI270_PWR_CTRL_REG,
+			      BMI270_PWR_CTRL_AUX_EN_MSK |
+			      BMI270_PWR_CTRL_GYR_EN_MSK |
+			      BMI270_PWR_CTRL_ACCEL_EN_MSK);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable accelerometer and gyroscope");
+
+	ret = regmap_set_bits(regmap, BMI270_ACC_CONF_REG,
+			      FIELD_PREP(BMI270_ACC_CONF_ODR_MSK,
+					 BMI270_ACC_CONF_ODR_100HZ) |
+			      FIELD_PREP(BMI270_ACC_CONF_BWP_MSK,
+					 BMI270_ACC_CONF_BWP_NORMAL_MODE) |
+			      BMI270_PWR_CONF_ADV_PWR_SAVE_MSK);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to configure accelerometer");
+
+	ret = regmap_set_bits(regmap, BMI270_GYR_CONF_REG,
+			      FIELD_PREP(BMI270_GYR_CONF_ODR_MSK,
+					 BMI270_GYR_CONF_ODR_200HZ) |
+			      FIELD_PREP(BMI270_GYR_CONF_BWP_MSK,
+					 BMI270_GYR_CONF_BWP_NORMAL_MODE) |
+			      BMI270_PWR_CONF_ADV_PWR_SAVE_MSK);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to configure gyroscope");
+
+	/* Enable FIFO_WKUP, Disable ADV_PWR_SAVE and FUP_EN */
+	ret = regmap_write(regmap, BMI270_PWR_CONF_REG,
+			   BMI270_PWR_CONF_FIFO_WKUP_MSK);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to set power configuration");
+
+	return 0;
+}
+
+static int bmi270_chip_init(struct bmi270_data *bmi270_device)
+{
+	int ret;
+
+	ret = bmi270_validate_chip_id(bmi270_device);
+	if (ret)
+		return ret;
+
+	ret = bmi270_write_calibration_data(bmi270_device);
+	if (ret)
+		return ret;
+
+	return bmi270_configure_imu(bmi270_device);
+}
+
+int bmi270_core_probe(struct device *dev, struct regmap *regmap)
+{
+	int ret;
+	struct bmi270_data *bmi270_device;
+	struct iio_dev *indio_dev;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*bmi270_device));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	bmi270_device = iio_priv(indio_dev);
+	bmi270_device->dev = dev;
+	bmi270_device->regmap = regmap;
+
+	ret = bmi270_chip_init(bmi270_device);
+	if (ret)
+		return ret;
+
+	indio_dev->channels = bmi270_channels;
+	indio_dev->num_channels = ARRAY_SIZE(bmi270_channels);
+	indio_dev->name = "bmi270";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &bmi270_info;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+EXPORT_SYMBOL_NS_GPL(bmi270_core_probe, IIO_BMI270);
+
+MODULE_AUTHOR("Alex Lanzano");
+MODULE_DESCRIPTION("BMI270 driver");
+MODULE_LICENSE("GPL");