iio: imu: Add driver for BMI323 IMU

The Bosch BMI323 is a 6-axis low-power IMU that provide measurements for
acceleration, angular rate, and temperature. This sensor includes
motion-triggered interrupt features, such as a step counter, tap detection,
and activity/inactivity interrupt capabilities.

The driver supports various functionalities, including data ready, FIFO
data handling, and events such as tap detection, step counting, and
activity interrupts.

Signed-off-by: Jagath Jog J <jagathjog1996@gmail.com>
Link: https://lore.kernel.org/r/20231013034808.8948-3-jagathjog1996@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/ABI/testing/sysfs-bus-iio

@@ -2254,3 +2254,21 @@ Description:
 		If a label is defined for this event add that to the event
 		specific attributes. This is useful for userspace to be able to
 		better identify an individual event.
+
+What:		/sys/.../events/in_accel_gesture_tap_wait_timeout
+KernelVersion:	6.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Enable tap gesture confirmation with timeout.
+
+What:		/sys/.../events/in_accel_gesture_tap_wait_dur
+KernelVersion:	6.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Timeout value in seconds for tap gesture confirmation.
+
+What:		/sys/.../events/in_accel_gesture_tap_wait_dur_available
+KernelVersion:	6.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		List of available timeout value for tap gesture confirmation.

MAINTAINERS

@@ -3647,6 +3647,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/accel/bosch,bma400.yaml
 F:	drivers/iio/accel/bma400*
 
+BOSCH SENSORTEC BMI323 IMU IIO DRIVER
+M:	Jagath Jog J <jagathjog1996@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/imu/bosch,bma400.yaml
+F:	drivers/iio/imu/bmi323/
+
 BPF JIT for ARM
 M:	Russell King <linux@armlinux.org.uk>
 M:	Puranjay Mohan <puranjay12@gmail.com>

drivers/iio/imu/Kconfig

@@ -53,6 +53,7 @@ config ADIS16480
 	  ADIS16485, ADIS16488 inertial sensors.
 
 source "drivers/iio/imu/bmi160/Kconfig"
+source "drivers/iio/imu/bmi323/Kconfig"
 source "drivers/iio/imu/bno055/Kconfig"
 
 config FXOS8700

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 += bmi323/
 obj-y += bno055/
 
 obj-$(CONFIG_FXOS8700) += fxos8700_core.o

drivers/iio/imu/bmi323/Kconfig

@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# BMI323 IMU driver
+#
+
+config BMI323
+	tristate
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+
+config BMI323_I2C
+	tristate "Bosch BMI323 I2C driver"
+	depends on I2C
+	select BMI323
+	select REGMAP_I2C
+	help
+	  Enable support for the Bosch BMI323 6-Axis IMU connected to I2C
+	  interface.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bmi323_i2c.
+
+config BMI323_SPI
+	tristate "Bosch BMI323 SPI driver"
+	depends on SPI
+	select BMI323
+	select REGMAP_SPI
+	help
+	  Enable support for the Bosch BMI323 6-Axis IMU connected to SPI
+	  interface.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bmi323_spi.

drivers/iio/imu/bmi323/Makefile

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for Bosch BMI323 IMU
+#
+obj-$(CONFIG_BMI323) += bmi323_core.o
+obj-$(CONFIG_BMI323_I2C) += bmi323_i2c.o
+obj-$(CONFIG_BMI323_SPI) += bmi323_spi.o

drivers/iio/imu/bmi323/bmi323.h

@@ -0,0 +1,209 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * IIO driver for Bosch BMI323 6-Axis IMU
+ *
+ * Copyright (C) 2023, Jagath Jog J <jagathjog1996@gmail.com>
+ */
+
+#ifndef _BMI323_H_
+#define _BMI323_H_
+
+#include <linux/bits.h>
+#include <linux/regmap.h>
+#include <linux/units.h>
+
+#define BMI323_I2C_DUMMY			2
+#define BMI323_SPI_DUMMY			1
+
+/* Register map */
+
+#define BMI323_CHIP_ID_REG			0x00
+#define BMI323_CHIP_ID_VAL			0x0043
+#define BMI323_CHIP_ID_MSK			GENMASK(7, 0)
+#define BMI323_ERR_REG				0x01
+#define BMI323_STATUS_REG			0x02
+#define BMI323_STATUS_POR_MSK			BIT(0)
+
+/* Accelero/Gyro/Temp data registers */
+#define BMI323_ACCEL_X_REG			0x03
+#define BMI323_GYRO_X_REG			0x06
+#define BMI323_TEMP_REG				0x09
+#define BMI323_ALL_CHAN_MSK			GENMASK(5, 0)
+
+/* Status registers */
+#define BMI323_STATUS_INT1_REG			0x0D
+#define BMI323_STATUS_INT2_REG			0x0E
+#define BMI323_STATUS_NOMOTION_MSK		BIT(0)
+#define BMI323_STATUS_MOTION_MSK		BIT(1)
+#define BMI323_STATUS_STP_WTR_MSK		BIT(5)
+#define BMI323_STATUS_TAP_MSK			BIT(8)
+#define BMI323_STATUS_ERROR_MSK			BIT(10)
+#define BMI323_STATUS_TMP_DRDY_MSK		BIT(11)
+#define BMI323_STATUS_GYR_DRDY_MSK		BIT(12)
+#define BMI323_STATUS_ACC_DRDY_MSK		BIT(13)
+#define BMI323_STATUS_ACC_GYR_DRDY_MSK		GENMASK(13, 12)
+#define BMI323_STATUS_FIFO_WTRMRK_MSK		BIT(14)
+#define BMI323_STATUS_FIFO_FULL_MSK		BIT(15)
+
+/* Feature registers */
+#define BMI323_FEAT_IO0_REG			0x10
+#define BMI323_FEAT_IO0_XYZ_NOMOTION_MSK	GENMASK(2, 0)
+#define BMI323_FEAT_IO0_XYZ_MOTION_MSK		GENMASK(5, 3)
+#define BMI323_FEAT_XYZ_MSK			GENMASK(2, 0)
+#define BMI323_FEAT_IO0_STP_CNT_MSK		BIT(9)
+#define BMI323_FEAT_IO0_S_TAP_MSK		BIT(12)
+#define BMI323_FEAT_IO0_D_TAP_MSK		BIT(13)
+#define BMI323_FEAT_IO1_REG			0x11
+#define BMI323_FEAT_IO1_ERR_MSK			GENMASK(3, 0)
+#define BMI323_FEAT_IO2_REG			0x12
+#define BMI323_FEAT_IO_STATUS_REG		0x14
+#define BMI323_FEAT_IO_STATUS_MSK		BIT(0)
+#define BMI323_FEAT_ENG_POLL			2000
+#define BMI323_FEAT_ENG_TIMEOUT			10000
+
+/* FIFO registers */
+#define BMI323_FIFO_FILL_LEVEL_REG		0x15
+#define BMI323_FIFO_DATA_REG			0x16
+
+/* Accelero/Gyro config registers */
+#define BMI323_ACC_CONF_REG			0x20
+#define BMI323_GYRO_CONF_REG			0x21
+#define BMI323_ACC_GYRO_CONF_MODE_MSK		GENMASK(14, 12)
+#define BMI323_ACC_GYRO_CONF_ODR_MSK		GENMASK(3, 0)
+#define BMI323_ACC_GYRO_CONF_SCL_MSK		GENMASK(6, 4)
+#define BMI323_ACC_GYRO_CONF_BW_MSK		BIT(7)
+#define BMI323_ACC_GYRO_CONF_AVG_MSK		GENMASK(10, 8)
+
+/* FIFO registers */
+#define BMI323_FIFO_WTRMRK_REG			0x35
+#define BMI323_FIFO_CONF_REG			0x36
+#define BMI323_FIFO_CONF_STP_FUL_MSK		BIT(0)
+#define BMI323_FIFO_CONF_ACC_GYR_EN_MSK		GENMASK(10, 9)
+#define BMI323_FIFO_ACC_GYR_MSK			GENMASK(1, 0)
+#define BMI323_FIFO_CTRL_REG			0x37
+#define BMI323_FIFO_FLUSH_MSK			BIT(0)
+
+/* Interrupt pin config registers */
+#define BMI323_IO_INT_CTR_REG			0x38
+#define BMI323_IO_INT1_LVL_MSK			BIT(0)
+#define BMI323_IO_INT1_OD_MSK			BIT(1)
+#define BMI323_IO_INT1_OP_EN_MSK		BIT(2)
+#define BMI323_IO_INT1_LVL_OD_OP_MSK		GENMASK(2, 0)
+#define BMI323_IO_INT2_LVL_MSK			BIT(8)
+#define BMI323_IO_INT2_OD_MSK			BIT(9)
+#define BMI323_IO_INT2_OP_EN_MSK		BIT(10)
+#define BMI323_IO_INT2_LVL_OD_OP_MSK		GENMASK(10, 8)
+#define BMI323_IO_INT_CONF_REG			0x39
+#define BMI323_IO_INT_LTCH_MSK			BIT(0)
+#define BMI323_INT_MAP1_REG			0x3A
+#define BMI323_INT_MAP2_REG			0x3B
+#define BMI323_NOMOTION_MSK			GENMASK(1, 0)
+#define BMI323_MOTION_MSK			GENMASK(3, 2)
+#define BMI323_STEP_CNT_MSK			GENMASK(11, 10)
+#define BMI323_TAP_MSK				GENMASK(1, 0)
+#define BMI323_TMP_DRDY_MSK			GENMASK(7, 6)
+#define BMI323_GYR_DRDY_MSK			GENMASK(9, 8)
+#define BMI323_ACC_DRDY_MSK			GENMASK(11, 10)
+#define BMI323_FIFO_WTRMRK_MSK			GENMASK(13, 12)
+#define BMI323_FIFO_FULL_MSK			GENMASK(15, 14)
+
+/* Feature registers */
+#define BMI323_FEAT_CTRL_REG			0x40
+#define BMI323_FEAT_ENG_EN_MSK			BIT(0)
+#define BMI323_FEAT_DATA_ADDR			0x41
+#define BMI323_FEAT_DATA_TX			0x42
+#define BMI323_FEAT_DATA_STATUS			0x43
+#define BMI323_FEAT_DATA_TX_RDY_MSK		BIT(1)
+#define BMI323_FEAT_EVNT_EXT_REG		0x47
+#define BMI323_FEAT_EVNT_EXT_S_MSK		BIT(3)
+#define BMI323_FEAT_EVNT_EXT_D_MSK		BIT(4)
+
+#define BMI323_CMD_REG				0x7E
+#define BMI323_RST_VAL				0xDEAF
+#define BMI323_CFG_RES_REG			0x7F
+
+/* Extended registers */
+#define BMI323_GEN_SET1_REG			0x02
+#define BMI323_GEN_SET1_MODE_MSK		BIT(0)
+#define BMI323_GEN_HOLD_DUR_MSK			GENMASK(4, 1)
+
+/* Any Motion/No Motion config registers */
+#define BMI323_ANYMO1_REG			0x05
+#define BMI323_NOMO1_REG			0x08
+#define BMI323_MO2_OFFSET			0x01
+#define BMI323_MO3_OFFSET			0x02
+#define BMI323_MO1_REF_UP_MSK			BIT(12)
+#define BMI323_MO1_SLOPE_TH_MSK			GENMASK(11, 0)
+#define BMI323_MO2_HYSTR_MSK			GENMASK(9, 0)
+#define BMI323_MO3_DURA_MSK			GENMASK(12, 0)
+
+/* Step counter config registers */
+#define BMI323_STEP_SC1_REG			0x10
+#define BMI323_STEP_SC1_WTRMRK_MSK		GENMASK(9, 0)
+#define BMI323_STEP_SC1_RST_CNT_MSK		BIT(10)
+#define BMI323_STEP_SC1_REG			0x10
+#define BMI323_STEP_LEN				2
+
+/* Tap gesture config registers */
+#define BMI323_TAP1_REG				0x1E
+#define BMI323_TAP1_AXIS_SEL_MSK		GENMASK(1, 0)
+#define BMI323_AXIS_XYZ_MSK			GENMASK(1, 0)
+#define BMI323_TAP1_TIMOUT_MSK			BIT(2)
+#define BMI323_TAP1_MAX_PEAKS_MSK		GENMASK(5, 3)
+#define BMI323_TAP1_MODE_MSK			GENMASK(7, 6)
+#define BMI323_TAP2_REG				0x1F
+#define BMI323_TAP2_THRES_MSK			GENMASK(9, 0)
+#define BMI323_TAP2_MAX_DUR_MSK			GENMASK(15, 10)
+#define BMI323_TAP3_REG				0x20
+#define BMI323_TAP3_QUIET_TIM_MSK		GENMASK(15, 12)
+#define BMI323_TAP3_QT_BW_TAP_MSK		GENMASK(11, 8)
+#define BMI323_TAP3_QT_AFT_GES_MSK		GENMASK(15, 12)
+
+#define BMI323_MOTION_THRES_SCALE		512
+#define BMI323_MOTION_HYSTR_SCALE		512
+#define BMI323_MOTION_DURAT_SCALE		50
+#define BMI323_TAP_THRES_SCALE			512
+#define BMI323_DUR_BW_TAP_SCALE			200
+#define BMI323_QUITE_TIM_GES_SCALE		25
+#define BMI323_MAX_GES_DUR_SCALE		25
+
+/*
+ * The formula to calculate temperature in C.
+ * See datasheet section 6.1.1, Register Map Overview
+ *
+ * T_C = (temp_raw / 512) + 23
+ */
+#define BMI323_TEMP_OFFSET			11776
+#define BMI323_TEMP_SCALE			1953125
+
+/*
+ * The BMI323 features a FIFO with a capacity of 2048 bytes. Each frame
+ * consists of accelerometer (X, Y, Z) data and gyroscope (X, Y, Z) data,
+ * totaling 6 words or 12 bytes. The FIFO buffer can hold a total of
+ * 170 frames.
+ *
+ * If a watermark interrupt is configured for 170 frames, the interrupt will
+ * trigger when the FIFO reaches 169 frames, so limit the maximum watermark
+ * level to 169 frames. In terms of data, 169 frames would equal 1014 bytes,
+ * which is approximately 2 frames before the FIFO reaches its full capacity.
+ * See datasheet section 5.7.3 FIFO Buffer Interrupts
+ */
+#define BMI323_BYTES_PER_SAMPLE			2
+#define BMI323_FIFO_LENGTH_IN_BYTES		2048
+#define BMI323_FIFO_FRAME_LENGTH		6
+#define BMI323_FIFO_FULL_IN_FRAMES		\
+	((BMI323_FIFO_LENGTH_IN_BYTES /		\
+	(BMI323_BYTES_PER_SAMPLE * BMI323_FIFO_FRAME_LENGTH)) - 1)
+#define BMI323_FIFO_FULL_IN_WORDS		\
+	(BMI323_FIFO_FULL_IN_FRAMES * BMI323_FIFO_FRAME_LENGTH)
+
+#define BMI323_INT_MICRO_TO_RAW(val, val2, scale) ((val) * (scale) + \
+						  ((val2) * (scale)) / MEGA)
+
+#define BMI323_RAW_TO_MICRO(raw, scale) ((((raw) % (scale)) * MEGA) / scale)
+
+struct device;
+int bmi323_core_probe(struct device *dev);
+extern const struct regmap_config bmi323_regmap_config;
+
+#endif

drivers/iio/imu/bmi323/bmi323_i2c.c

@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * I2C driver for Bosch BMI323 6-Axis IMU.
+ *
+ * Copyright (C) 2023, Jagath Jog J <jagathjog1996@gmail.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "bmi323.h"
+
+struct bmi323_i2c_priv {
+	struct i2c_client *i2c;
+	u8 i2c_rx_buffer[BMI323_FIFO_LENGTH_IN_BYTES + BMI323_I2C_DUMMY];
+};
+
+/*
+ * From BMI323 datasheet section 4: Notes on the Serial Interface Support.
+ * Each I2C register read operation requires to read two dummy bytes before
+ * the actual payload.
+ */
+static int bmi323_regmap_i2c_read(void *context, const void *reg_buf,
+				  size_t reg_size, void *val_buf,
+				  size_t val_size)
+{
+	struct bmi323_i2c_priv *priv = context;
+	struct i2c_msg msgs[2];
+	int ret;
+
+	msgs[0].addr = priv->i2c->addr;
+	msgs[0].flags = priv->i2c->flags;
+	msgs[0].len = reg_size;
+	msgs[0].buf = (u8 *)reg_buf;
+
+	msgs[1].addr = priv->i2c->addr;
+	msgs[1].len = val_size + BMI323_I2C_DUMMY;
+	msgs[1].buf = priv->i2c_rx_buffer;
+	msgs[1].flags = priv->i2c->flags | I2C_M_RD;
+
+	ret = i2c_transfer(priv->i2c->adapter, msgs, ARRAY_SIZE(msgs));
+	if (ret < 0)
+		return -EIO;
+
+	memcpy(val_buf, priv->i2c_rx_buffer + BMI323_I2C_DUMMY, val_size);
+
+	return 0;
+}
+
+static int bmi323_regmap_i2c_write(void *context, const void *data,
+				   size_t count)
+{
+	struct bmi323_i2c_priv *priv = context;
+	u8 reg;
+
+	reg = *(u8 *)data;
+	return i2c_smbus_write_i2c_block_data(priv->i2c, reg,
+					      count - sizeof(u8),
+					      data + sizeof(u8));
+}
+
+static struct regmap_bus bmi323_regmap_bus = {
+	.read = bmi323_regmap_i2c_read,
+	.write = bmi323_regmap_i2c_write,
+};
+
+const struct regmap_config bmi323_i2c_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = BMI323_CFG_RES_REG,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
+static int bmi323_i2c_probe(struct i2c_client *i2c)
+{
+	struct device *dev = &i2c->dev;
+	struct bmi323_i2c_priv *priv;
+	struct regmap *regmap;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->i2c = i2c;
+	regmap = devm_regmap_init(dev, &bmi323_regmap_bus, priv,
+				  &bmi323_i2c_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap),
+				     "Failed to initialize I2C Regmap\n");
+
+	return bmi323_core_probe(dev);
+}
+
+static const struct i2c_device_id bmi323_i2c_ids[] = {
+	{ "bmi323" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, bmi323_i2c_ids);
+
+static const struct of_device_id bmi323_of_i2c_match[] = {
+	{ .compatible = "bosch,bmi323" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, bmi323_of_i2c_match);
+
+static struct i2c_driver bmi323_i2c_driver = {
+	.driver = {
+		.name = "bmi323",
+		.of_match_table = bmi323_of_i2c_match,
+	},
+	.probe = bmi323_i2c_probe,
+	.id_table = bmi323_i2c_ids,
+};
+module_i2c_driver(bmi323_i2c_driver);
+
+MODULE_DESCRIPTION("Bosch BMI323 IMU driver");
+MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(IIO_BMI323);

drivers/iio/imu/bmi323/bmi323_spi.c

@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SPI driver for Bosch BMI323 6-Axis IMU.
+ *
+ * Copyright (C) 2023, Jagath Jog J <jagathjog1996@gmail.com>
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "bmi323.h"
+
+/*
+ * From BMI323 datasheet section 4: Notes on the Serial Interface Support.
+ * Each SPI register read operation requires to read one dummy byte before
+ * the actual payload.
+ */
+static int bmi323_regmap_spi_read(void *context, const void *reg_buf,
+				  size_t reg_size, void *val_buf,
+				  size_t val_size)
+{
+	struct spi_device *spi = context;
+
+	return spi_write_then_read(spi, reg_buf, reg_size, val_buf, val_size);
+}
+
+static int bmi323_regmap_spi_write(void *context, const void *data,
+				   size_t count)
+{
+	struct spi_device *spi = context;
+	u8 *data_buff = (u8 *)data;
+
+	data_buff[1] = data_buff[0];
+	return spi_write(spi, data_buff + 1, count - 1);
+}
+
+static struct regmap_bus bmi323_regmap_bus = {
+	.read = bmi323_regmap_spi_read,
+	.write = bmi323_regmap_spi_write,
+};
+
+const struct regmap_config bmi323_spi_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.pad_bits = 8,
+	.read_flag_mask = BIT(7),
+	.max_register = BMI323_CFG_RES_REG,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
+static int bmi323_spi_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init(dev, &bmi323_regmap_bus, dev,
+				  &bmi323_spi_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap),
+				     "Failed to initialize SPI Regmap\n");
+
+	return bmi323_core_probe(dev);
+}
+
+static const struct spi_device_id bmi323_spi_ids[] = {
+	{ "bmi323" },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, bmi323_spi_ids);
+
+static const struct of_device_id bmi323_of_spi_match[] = {
+	{ .compatible = "bosch,bmi323" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, bmi323_of_spi_match);
+
+static struct spi_driver bmi323_spi_driver = {
+	.driver = {
+		.name = "bmi323",
+		.of_match_table = bmi323_of_spi_match,
+	},
+	.probe = bmi323_spi_probe,
+	.id_table = bmi323_spi_ids,
+};
+module_spi_driver(bmi323_spi_driver);
+
+MODULE_DESCRIPTION("Bosch BMI323 IMU driver");
+MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(IIO_BMI323);