[PATCH v5 2/2] iio: (bma400) add driver for the BMA400

Dan Robertson
2019-12-09T02:00:40Z

Add a IIO driver for the Bosch BMA400 3-axes ultra-low power accelerometer.
The driver supports reading from the acceleration and temperature
registers. The driver also supports reading and configuring the output data
rate, oversampling ratio, and scale.

Signed-off-by: Dan Robertson <dan@dlrobertson.com>
---
drivers/iio/accel/Kconfig | 16 +
drivers/iio/accel/Makefile | 2 +
drivers/iio/accel/bma400.h | 95 ++++
drivers/iio/accel/bma400_core.c | 823 ++++++++++++++++++++++++++++++++
drivers/iio/accel/bma400_i2c.c | 62 +++
5 files changed, 998 insertions(+)
create mode 100644 drivers/iio/accel/bma400.h
create mode 100644 drivers/iio/accel/bma400_core.c
create mode 100644 drivers/iio/accel/bma400_i2c.c

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index d4ef35aeb579..dc9bc646d403 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -112,6 +112,22 @@ config BMA220
To compile this driver as a module, choose M here: the
module will be called bma220_spi.

+config BMA400
+ tristate "Bosch BMA400 3-Axis Accelerometer Driver"
+ select REGMAP
+ select BMA400_I2C if (I2C)
+ help
+ Say Y here if you want to build a driver for the Bosch BMA400
+ triaxial acceleration sensor.
+
+ To compile this driver as a module, choose M here: the
+ module will be called bma400_core and you will also get
+ bma400_i2c for I2C.
+
+config BMA400_I2C
+ tristate
+ depends on BMA400
+
config BMC150_ACCEL
tristate "Bosch BMC150 Accelerometer Driver"
select IIO_BUFFER
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 56bd0215e0d4..3a051cf37f40 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -14,6 +14,8 @@ obj-$(CONFIG_ADXL372_I2C) += adxl372_i2c.o
obj-$(CONFIG_ADXL372_SPI) += adxl372_spi.o
obj-$(CONFIG_BMA180) += bma180.o
obj-$(CONFIG_BMA220) += bma220_spi.o
+obj-$(CONFIG_BMA400) += bma400_core.o
+obj-$(CONFIG_BMA400_I2C) += bma400_i2c.o
obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
obj-$(CONFIG_BMC150_ACCEL_I2C) += bmc150-accel-i2c.o
obj-$(CONFIG_BMC150_ACCEL_SPI) += bmc150-accel-spi.o
diff --git a/drivers/iio/accel/bma400.h b/drivers/iio/accel/bma400.h
new file mode 100644
index 000000000000..6f3cbfb11b91
--- /dev/null
+++ b/drivers/iio/accel/bma400.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Register constants and other forward declarations needed by the bma400
+ * sources.
+ *
+ * Copyright 2019 Dan Robertson <dan@dlrobertson.com>
+ */
+
+#ifndef _BMA400_H_
+#define _BMA400_H_
+
+#include <linux/bits.h>
+#include <linux/regmap.h>
+
+/*
+ * Read-Only Registers
+ */
+
+/* Status and ID registers */
+#define BMA400_CHIP_ID_REG 0x00
+#define BMA400_ERR_REG 0x02
+#define BMA400_STATUS_REG 0x03
+
+/* Acceleration registers */
+#define BMA400_X_AXIS_LSB_REG 0x04
+#define BMA400_X_AXIS_MSB_REG 0x05
+#define BMA400_Y_AXIS_LSB_REG 0x06
+#define BMA400_Y_AXIS_MSB_REG 0x07
+#define BMA400_Z_AXIS_LSB_REG 0x08
+#define BMA400_Z_AXIS_MSB_REG 0x09
+
+/* Sensor time registers */
+#define BMA400_SENSOR_TIME0 0x0a
+#define BMA400_SENSOR_TIME1 0x0b
+#define BMA400_SENSOR_TIME2 0x0c
+
+/* Event and interrupt registers */
+#define BMA400_EVENT_REG 0x0d
+#define BMA400_INT_STAT0_REG 0x0e
+#define BMA400_INT_STAT1_REG 0x0f
+#define BMA400_INT_STAT2_REG 0x10
+
+/* Temperature register */
+#define BMA400_TEMP_DATA_REG 0x11
+
+/* FIFO length and data registers */
+#define BMA400_FIFO_LENGTH0_REG 0x12
+#define BMA400_FIFO_LENGTH1_REG 0x13
+#define BMA400_FIFO_DATA_REG 0x14
+
+/* Step count registers */
+#define BMA400_STEP_CNT0_REG 0x15
+#define BMA400_STEP_CNT1_REG 0x16
+#define BMA400_STEP_CNT3_REG 0x17
+#define BMA400_STEP_STAT_REG 0x18
+
+/*
+ * Read-write configuration registers
+ */
+#define BMA400_ACC_CONFIG0_REG 0x19
+#define BMA400_ACC_CONFIG1_REG 0x1a
+#define BMA400_ACC_CONFIG2_REG 0x1b
+#define BMA400_CMD_REG 0x7e
+
+/* Chip ID of BMA 400 devices found in the chip ID register. */
+#define BMA400_ID_REG_VAL 0x90
+
+#define BMA400_LP_OSR_SHIFT 0x05
+#define BMA400_NP_OSR_SHIFT 0x04
+#define BMA400_SCALE_SHIFT 0x06
+
+#define BMA400_TWO_BITS_MASK GENMASK(1, 0)
+#define BMA400_LP_OSR_MASK GENMASK(6, BMA400_LP_OSR_SHIFT)
+#define BMA400_NP_OSR_MASK GENMASK(5, BMA400_NP_OSR_SHIFT)
+#define BMA400_ACC_ODR_MASK GENMASK(3, 0)
+#define BMA400_ACC_SCALE_MASK GENMASK(7, BMA400_SCALE_SHIFT)
+
+#define BMA400_ACC_ODR_MIN_RAW 0x05
+#define BMA400_ACC_ODR_LP_RAW 0x06
+#define BMA400_ACC_ODR_MAX_RAW 0x0b
+
+#define BMA400_ACC_ODR_MAX_HZ 800
+#define BMA400_ACC_ODR_MIN_WHOLE_HZ 25
+#define BMA400_ACC_ODR_MIN_HZ 12
+
+#define BMA400_SCALE_MIN 38357
+#define BMA400_SCALE_MAX 306862
+
+extern const struct regmap_config bma400_regmap_config;
+
+int bma400_probe(struct device *dev, struct regmap *regmap, const char *name);
+
+int bma400_remove(struct device *dev);
+
+#endif
diff --git a/drivers/iio/accel/bma400_core.c b/drivers/iio/accel/bma400_core.c
new file mode 100644
index 000000000000..6f5c7cdf42d2
--- /dev/null
+++ b/drivers/iio/accel/bma400_core.c
@@ -0,0 +1,823 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Core IIO driver for Bosch BMA400 triaxial acceleration sensor.
+ *
+ * Copyright 2019 Dan Robertson <dan@dlrobertson.com>
+ *
+ * TODO:
+ * - Support for power management
+ * - Support events and interrupts
+ * - Create channel for step count
+ * - Create channel for sensor time
+ */
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+
+#include "bma400.h"
+
+/*
+ * The G-range selection may be one of 2g, 4g, 8, or 16g. The scale may
+ * be selected with the acc_range bits of the ACC_CONFIG1 register.
+ * NB: This buffer is populated in the device init.
+ */
+static int bma400_scales[8];
+
+/*
+ * See the ACC_CONFIG1 section of the datasheet.
+ * NB: This buffer is populated in the device init.
+ */
+static int bma400_sample_freqs[14];
+
+static const int bma400_osr_range[] = { 0, 1, 3 };
+
+/* See the ACC_CONFIG0 section of the datasheet */
+enum bma400_power_mode {
+ POWER_MODE_SLEEP = 0x00,
+ POWER_MODE_LOW = 0x01,
+ POWER_MODE_NORMAL = 0x02,
+ POWER_MODE_INVALID = 0x03,
+};
+
+struct bma400_sample_freq {
+ int hz;
+ int uhz;
+};
+
+struct bma400_data {
+ struct device *dev;
+ struct mutex mutex; /* data register lock */
+ struct iio_mount_matrix orientation;
+ struct regmap *regmap;
+ enum bma400_power_mode power_mode;
+ struct bma400_sample_freq sample_freq;
+ int oversampling_ratio;
+ int scale;
+};
+
+static bool bma400_is_writable_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case BMA400_CHIP_ID_REG:
+ case BMA400_ERR_REG:
+ case BMA400_STATUS_REG:
+ case BMA400_X_AXIS_LSB_REG:
+ case BMA400_X_AXIS_MSB_REG:
+ case BMA400_Y_AXIS_LSB_REG:
+ case BMA400_Y_AXIS_MSB_REG:
+ case BMA400_Z_AXIS_LSB_REG:
+ case BMA400_Z_AXIS_MSB_REG:
+ case BMA400_SENSOR_TIME0:
+ case BMA400_SENSOR_TIME1:
+ case BMA400_SENSOR_TIME2:
+ case BMA400_EVENT_REG:
+ case BMA400_INT_STAT0_REG:
+ case BMA400_INT_STAT1_REG:
+ case BMA400_INT_STAT2_REG:
+ case BMA400_TEMP_DATA_REG:
+ case BMA400_FIFO_LENGTH0_REG:
+ case BMA400_FIFO_LENGTH1_REG:
+ case BMA400_FIFO_DATA_REG:
+ case BMA400_STEP_CNT0_REG:
+ case BMA400_STEP_CNT1_REG:
+ case BMA400_STEP_CNT3_REG:
+ case BMA400_STEP_STAT_REG:
+ return false;
+ default:
+ return true;
+ }
+}
+
+static bool bma400_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case BMA400_ERR_REG:
+ case BMA400_STATUS_REG:
+ case BMA400_X_AXIS_LSB_REG:
+ case BMA400_X_AXIS_MSB_REG:
+ case BMA400_Y_AXIS_LSB_REG:
+ case BMA400_Y_AXIS_MSB_REG:
+ case BMA400_Z_AXIS_LSB_REG:
+ case BMA400_Z_AXIS_MSB_REG:
+ case BMA400_SENSOR_TIME0:
+ case BMA400_SENSOR_TIME1:
+ case BMA400_SENSOR_TIME2:
+ case BMA400_EVENT_REG:
+ case BMA400_INT_STAT0_REG:
+ case BMA400_INT_STAT1_REG:
+ case BMA400_INT_STAT2_REG:
+ case BMA400_TEMP_DATA_REG:
+ case BMA400_FIFO_LENGTH0_REG:
+ case BMA400_FIFO_LENGTH1_REG:
+ case BMA400_FIFO_DATA_REG:
+ case BMA400_STEP_CNT0_REG:
+ case BMA400_STEP_CNT1_REG:
+ case BMA400_STEP_CNT3_REG:
+ case BMA400_STEP_STAT_REG:
+ return true;
+ default:
+ return false;
+ }
+}
+
+const struct regmap_config bma400_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = BMA400_CMD_REG,
+ .cache_type = REGCACHE_RBTREE,
+ .writeable_reg = bma400_is_writable_reg,
+ .volatile_reg = bma400_is_volatile_reg,
+};
+EXPORT_SYMBOL(bma400_regmap_config);
+
+static const struct iio_mount_matrix *
+bma400_accel_get_mount_matrix(const struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct bma400_data *data = iio_priv(indio_dev);
+
+ return &data->orientation;
+}
+
+static const struct iio_chan_spec_ext_info bma400_ext_info[] = {
+ IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, bma400_accel_get_mount_matrix),
+ { }
+};
+
+#define BMA400_ACC_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_SAMP_FREQ) | \
+ BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
+ .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
+ BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
+ .ext_info = bma400_ext_info, \
+}
+
+static const struct iio_chan_spec bma400_channels[] = {
+ BMA400_ACC_CHANNEL(X),
+ BMA400_ACC_CHANNEL(Y),
+ BMA400_ACC_CHANNEL(Z),
+ {
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ },
+};
+
+static int bma400_get_temp_reg(struct bma400_data *data, int *val, int *val2)
+{
+ unsigned int raw_temp;
+ int host_temp;
+ int ret;
+
+ if (data->power_mode == POWER_MODE_SLEEP)
+ return -EBUSY;
+
+ ret = regmap_read(data->regmap, BMA400_TEMP_DATA_REG, &raw_temp);
+ if (ret < 0)
+ return ret;
+
+ host_temp = sign_extend32(raw_temp, 7);
+ /*
+ * The formula for the TEMP_DATA register in the datasheet
+ * is: x * 0.5 + 23
+ */
+ *val = (host_temp >> 1) + 23;
+ *val2 = (host_temp & 0x1) * 500000;
+ return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int bma400_get_accel_reg(struct bma400_data *data,
+ const struct iio_chan_spec *chan,
+ int *val)
+{
+ __le16 raw_accel;
+ int lsb_reg;
+ int ret;
+
+ if (data->power_mode == POWER_MODE_SLEEP)
+ return -EBUSY;
+
+ switch (chan->channel2) {
+ case IIO_MOD_X:
+ lsb_reg = BMA400_X_AXIS_LSB_REG;
+ break;
+ case IIO_MOD_Y:
+ lsb_reg = BMA400_Y_AXIS_LSB_REG;
+ break;
+ case IIO_MOD_Z:
+ lsb_reg = BMA400_Z_AXIS_LSB_REG;
+ break;
+ default:
+ dev_err(data->dev, "invalid axis channel modifier\n");
+ return -EINVAL;
+ }
+
+ /* bulk read two registers, with the base being the LSB register */
+ ret = regmap_bulk_read(data->regmap, lsb_reg, &raw_accel,
+ sizeof(raw_accel));
+ if (ret < 0)
+ return ret;
+
+ *val = sign_extend32(le16_to_cpu(raw_accel), 11);
+ return IIO_VAL_INT;
+}
+
+static void bma400_output_data_rate_from_raw(int raw, unsigned int *val,
+ unsigned int *val2)
+{
+ *val = BMA400_ACC_ODR_MAX_HZ >> (BMA400_ACC_ODR_MAX_RAW - raw);
+ if (raw > BMA400_ACC_ODR_MIN_RAW)
+ *val2 = 0;
+ else
+ *val2 = 500000;
+}
+
+static int bma400_get_accel_output_data_rate(struct bma400_data *data)
+{
+ unsigned int val;
+ unsigned int odr;
+ int ret;
+
+ switch (data->power_mode) {
+ case POWER_MODE_LOW:
+ /*
+ * Runs at a fixed rate in low-power mode. See section 4.3
+ * in the datasheet.
+ */
+ bma400_output_data_rate_from_raw(BMA400_ACC_ODR_LP_RAW,
+ &data->sample_freq.hz,
+ &data->sample_freq.uhz);
+ return 0;
+ case POWER_MODE_NORMAL:
+ /*
+ * In normal mode the ODR can be found in the ACC_CONFIG1
+ * register.
+ */
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG1_REG, &val);
+ if (ret < 0)
+ goto error;
+
+ odr = val & BMA400_ACC_ODR_MASK;
+ if (odr < BMA400_ACC_ODR_MIN_RAW ||
+ odr > BMA400_ACC_ODR_MAX_RAW) {
+ ret = -EINVAL;
+ goto error;
+ }
+
+ bma400_output_data_rate_from_raw(odr, &data->sample_freq.hz,
+ &data->sample_freq.uhz);
+ return 0;
+ case POWER_MODE_SLEEP:
+ data->sample_freq.hz = 0;
+ data->sample_freq.uhz = 0;
+ return 0;
+ default:
+ ret = 0;
+ goto error;
+ }
+error:
+ data->sample_freq.hz = -1;
+ data->sample_freq.uhz = -1;
+ return ret;
+}
+
+static int bma400_set_accel_output_data_rate(struct bma400_data *data,
+ int hz, int uhz)
+{
+ unsigned int idx;
+ unsigned int odr;
+ unsigned int val;
+ int ret;
+
+ if (hz >= BMA400_ACC_ODR_MIN_WHOLE_HZ) {
+ if (uhz || hz % BMA400_ACC_ODR_MIN_WHOLE_HZ)
+ return -EINVAL;
+
+ val = hz / BMA400_ACC_ODR_MIN_WHOLE_HZ;
+ idx = __ffs(val);
+
+ if (val ^ BIT(idx))
+ return -EINVAL;
+
+ idx += BMA400_ACC_ODR_MIN_RAW + 1;
+ } else if (hz == BMA400_ACC_ODR_MIN_HZ && uhz == 500000) {
+ idx = BMA400_ACC_ODR_MIN_RAW;
+ } else {
+ return -EINVAL;
+ }
+
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG1_REG, &val);
+ if (ret < 0)
+ return ret;
+
+ /* preserve the range and normal mode osr */
+ odr = (~BMA400_ACC_ODR_MASK & val) | idx;
+
+ ret = regmap_write(data->regmap, BMA400_ACC_CONFIG1_REG, odr);
+ if (ret < 0)
+ return ret;
+
+ bma400_output_data_rate_from_raw(idx, &data->sample_freq.hz,
+ &data->sample_freq.uhz);
+ return 0;
+}
+
+static int bma400_get_accel_oversampling_ratio(struct bma400_data *data)
+{
+ unsigned int val;
+ unsigned int osr;
+ int ret;
+
+ /*
+ * The oversampling ratio is stored in a different register
+ * based on the power-mode. In normal mode the OSR is stored
+ * in ACC_CONFIG1. In low-power mode it is stored in
+ * ACC_CONFIG0.
+ */
+ switch (data->power_mode) {
+ case POWER_MODE_LOW:
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG0_REG, &val);
+ if (ret < 0) {
+ data->oversampling_ratio = -1;
+ return ret;
+ }
+
+ osr = (val & BMA400_LP_OSR_MASK) >> BMA400_LP_OSR_SHIFT;
+
+ data->oversampling_ratio = osr;
+ return 0;
+ case POWER_MODE_NORMAL:
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG1_REG, &val);
+ if (ret < 0) {
+ data->oversampling_ratio = -1;
+ return ret;
+ }
+
+ osr = (val & BMA400_NP_OSR_MASK) >> BMA400_NP_OSR_SHIFT;
+
+ data->oversampling_ratio = osr;
+ return 0;
+ case POWER_MODE_SLEEP:
+ data->oversampling_ratio = 0;
+ return 0;
+ default:
+ data->oversampling_ratio = -1;
+ return 0;
+ }
+}
+
+static int bma400_set_accel_oversampling_ratio(struct bma400_data *data,
+ int val)
+{
+ unsigned int acc_config;
+ int ret;
+
+ if (val & ~BMA400_TWO_BITS_MASK)
+ return -EINVAL;
+
+ /*
+ * The oversampling ratio is stored in a different register
+ * based on the power-mode.
+ */
+ switch (data->power_mode) {
+ case POWER_MODE_LOW:
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG0_REG,
+ &acc_config);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(data->regmap, BMA400_ACC_CONFIG0_REG,
+ (acc_config & ~BMA400_LP_OSR_MASK) |
+ (val << BMA400_LP_OSR_SHIFT));
+ if (ret < 0) {
+ dev_err(data->dev, "Failed to write out OSR\n");
+ return ret;
+ }
+
+ data->oversampling_ratio = val;
+ return 0;
+ case POWER_MODE_NORMAL:
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG1_REG,
+ &acc_config);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(data->regmap, BMA400_ACC_CONFIG1_REG,
+ (acc_config & ~BMA400_NP_OSR_MASK) |
+ (val << BMA400_NP_OSR_SHIFT));
+ if (ret < 0) {
+ dev_err(data->dev, "Failed to write out OSR\n");
+ return ret;
+ }
+
+ data->oversampling_ratio = val;
+ return 0;
+ default:
+ return -EINVAL;
+ }
+ return ret;
+}
+
+static void bma400_accel_scale_from_raw(int raw, unsigned int *val)
+{
+ *val = BMA400_SCALE_MIN * (1 << raw);
+}
+
+int bma400_accel_scale_to_raw(struct bma400_data *data, unsigned int val)
+{
+ int scale = val / BMA400_SCALE_MIN;
+ int raw;
+
+ if (scale == 0)
+ return -EINVAL;
+
+ raw = __ffs(scale);
+
+ if (val % BMA400_SCALE_MIN || scale ^ BIT(raw))
+ return -EINVAL;
+
+ return raw;
+}
+
+static int bma400_get_accel_scale(struct bma400_data *data)
+{
+ unsigned int raw_scale;
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG1_REG, &val);
+ if (ret < 0)
+ return ret;
+
+ raw_scale = (val & BMA400_ACC_SCALE_MASK) >> BMA400_SCALE_SHIFT;
+ if (raw_scale > BMA400_TWO_BITS_MASK)
+ return -EINVAL;
+
+ bma400_accel_scale_from_raw(raw_scale, &data->scale);
+
+ return 0;
+}
+
+static int bma400_set_accel_scale(struct bma400_data *data, unsigned int val)
+{
+ unsigned int acc_config;
+ int raw;
+ int ret;
+
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG1_REG, &acc_config);
+ if (ret < 0)
+ return ret;
+
+ raw = bma400_accel_scale_to_raw(data, val);
+ if (raw < 0)
+ return raw;
+
+ ret = regmap_write(data->regmap, BMA400_ACC_CONFIG1_REG,
+ (acc_config & ~BMA400_ACC_SCALE_MASK) |
+ (raw << BMA400_SCALE_SHIFT));
+ if (ret < 0)
+ return ret;
+
+ data->scale = val;
+ return 0;
+}
+
+static int bma400_get_power_mode(struct bma400_data *data)
+{
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read(data->regmap, BMA400_STATUS_REG, &val);
+ if (ret < 0) {
+ dev_err(data->dev, "Failed to read status register\n");
+ return ret;
+ }
+
+ data->power_mode = (val >> 1) & BMA400_TWO_BITS_MASK;
+ return 0;
+}
+
+static int bma400_set_power_mode(struct bma400_data *data,
+ enum bma400_power_mode mode)
+{
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read(data->regmap, BMA400_ACC_CONFIG0_REG, &val);
+ if (ret < 0)
+ return ret;
+
+ if (data->power_mode == mode)
+ return 0;
+
+ if (mode == POWER_MODE_INVALID)
+ return -EINVAL;
+
+ /* Preserve the low-power oversample ratio etc */
+ ret = regmap_write(data->regmap, BMA400_ACC_CONFIG0_REG,
+ mode | (val & ~BMA400_TWO_BITS_MASK));
+ if (ret < 0) {
+ dev_err(data->dev, "Failed to write to power-mode\n");
+ return ret;
+ }
+
+ data->power_mode = mode;
+
+ /*
+ * Update our cached osr and odr based on the new
+ * power-mode.
+ */
+ bma400_get_accel_output_data_rate(data);
+ bma400_get_accel_oversampling_ratio(data);
+ return 0;
+}
+
+static void bma400_init_tables(void)
+{
+ int raw;
+ int i;
+
+ for (i = 0; i + 1 < ARRAY_SIZE(bma400_sample_freqs); i += 2) {
+ raw = (i / 2) + 5;
+ bma400_output_data_rate_from_raw(raw, &bma400_sample_freqs[i],
+ &bma400_sample_freqs[i + 1]);
+ }
+
+ for (i = 0; i + 1 < ARRAY_SIZE(bma400_scales); i += 2) {
+ raw = i / 2;
+ bma400_scales[i] = 0;
+ bma400_accel_scale_from_raw(raw, &bma400_scales[i + 1]);
+ }
+}
+
+static int bma400_init(struct bma400_data *data)
+{
+ unsigned int val;
+ int ret;
+
+ /* Try to read chip_id register. It must return 0x90. */
+ ret = regmap_read(data->regmap, BMA400_CHIP_ID_REG, &val);
+ if (ret < 0) {
+ dev_err(data->dev, "Failed to read chip id register\n");
+ return ret;
+ }
+
+ if (val != BMA400_ID_REG_VAL) {
+ dev_err(data->dev, "Chip ID mismatch\n");
+ return -ENODEV;
+ }
+
+ ret = bma400_get_power_mode(data);
+ if (ret < 0) {
+ dev_err(data->dev, "Failed to get the initial power-mode\n");
+ return ret;
+ }
+
+ if (data->power_mode != POWER_MODE_NORMAL) {
+ ret = bma400_set_power_mode(data, POWER_MODE_NORMAL);
+ if (ret < 0) {
+ dev_err(data->dev, "Failed to wake up the device\n");
+ return ret;
+ }
+ /*
+ * TODO: The datasheet waits 1500us here in the example, but
+ * lists 2/ODR as the wakeup time.
+ */
+ usleep_range(1500, 2000);
+ }
+
+ bma400_init_tables();
+
+ ret = bma400_get_accel_output_data_rate(data);
+ if (ret < 0)
+ return ret;
+
+ ret = bma400_get_accel_oversampling_ratio(data);
+ if (ret < 0)
+ return ret;
+
+ ret = bma400_get_accel_scale(data);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Once the interrupt engine is supported we might use the
+ * data_src_reg, but for now ensure this is set to the
+ * variable ODR filter selectable by the sample frequency
+ * channel.
+ */
+ return regmap_write(data->regmap, BMA400_ACC_CONFIG2_REG, 0x00);
+}
+
+static int bma400_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct bma400_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_PROCESSED:
+ mutex_lock(&data->mutex);
+ ret = bma400_get_temp_reg(data, val, val2);
+ mutex_unlock(&data->mutex);
+ return ret;
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&data->mutex);
+ ret = bma400_get_accel_reg(data, chan, val);
+ mutex_unlock(&data->mutex);
+ return ret;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ switch (chan->type) {
+ case IIO_ACCEL:
+ if (data->sample_freq.hz < 0)
+ return -EINVAL;
+
+ *val = data->sample_freq.hz;
+ *val2 = data->sample_freq.uhz;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_TEMP:
+ /*
+ * Runs at a fixed sampling frequency. See Section 4.4
+ * of the datasheet.
+ */
+ *val = 6;
+ *val2 = 250000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+ case IIO_CHAN_INFO_SCALE:
+ *val = 0;
+ *val2 = data->scale;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ /*
+ * TODO: We could avoid this logic and returning -EINVAL here if
+ * we set both the low-power and normal mode OSR registers when
+ * we configure the device.
+ */
+ if (data->oversampling_ratio < 0)
+ return -EINVAL;
+
+ *val = data->oversampling_ratio;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int bma400_read_avail(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ const int **vals, int *type, int *length,
+ long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ *type = IIO_VAL_INT_PLUS_MICRO;
+ *vals = bma400_scales;
+ *length = ARRAY_SIZE(bma400_scales);
+ return IIO_AVAIL_LIST;
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ *type = IIO_VAL_INT;
+ *vals = bma400_osr_range;
+ *length = ARRAY_SIZE(bma400_osr_range);
+ return IIO_AVAIL_RANGE;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *type = IIO_VAL_INT_PLUS_MICRO;
+ *vals = bma400_sample_freqs;
+ *length = ARRAY_SIZE(bma400_sample_freqs);
+ return IIO_AVAIL_LIST;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int bma400_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int val, int val2,
+ long mask)
+{
+ struct bma400_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ /*
+ * The sample frequency is readonly for the temperature
+ * register and a fixed value in low-power mode.
+ */
+ if (chan->type != IIO_ACCEL || val > BMA400_ACC_ODR_MAX_HZ)
+ return -EINVAL;
+
+ mutex_lock(&data->mutex);
+ ret = bma400_set_accel_output_data_rate(data, val, val2);
+ mutex_unlock(&data->mutex);
+ return ret;
+ case IIO_CHAN_INFO_SCALE:
+ if (val != 0 || val2 > BMA400_SCALE_MAX)
+ return -EINVAL;
+
+ mutex_lock(&data->mutex);
+ ret = bma400_set_accel_scale(data, val2);
+ mutex_unlock(&data->mutex);
+ return ret;
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ mutex_lock(&data->mutex);
+ ret = bma400_set_accel_oversampling_ratio(data, val);
+ mutex_unlock(&data->mutex);
+ return ret;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int bma400_write_raw_get_fmt(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CHAN_INFO_SCALE:
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info bma400_info = {
+ .read_raw = bma400_read_raw,
+ .read_avail = bma400_read_avail,
+ .write_raw = bma400_write_raw,
+ .write_raw_get_fmt = bma400_write_raw_get_fmt,
+};
+
+int bma400_probe(struct device *dev, struct regmap *regmap, const char *name)
+{
+ struct iio_dev *indio_dev;
+ struct bma400_data *data;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ data->regmap = regmap;
+ data->dev = dev;
+
+ ret = bma400_init(data);
+ if (ret < 0)
+ return ret;
+
+ ret = iio_read_mount_matrix(dev, "mount-matrix", &data->orientation);
+ if (ret)
+ return ret;
+
+ mutex_init(&data->mutex);
+ indio_dev->dev.parent = dev;
+ indio_dev->name = name;
+ indio_dev->info = &bma400_info;
+ indio_dev->channels = bma400_channels;
+ indio_dev->num_channels = ARRAY_SIZE(bma400_channels);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ dev_set_drvdata(dev, indio_dev);
+
+ return iio_device_register(indio_dev);
+}
+EXPORT_SYMBOL(bma400_probe);
+
+int bma400_remove(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct bma400_data *data = iio_priv(indio_dev);
+ int ret;
+
+ mutex_lock(&data->mutex);
+ ret = bma400_set_power_mode(data, POWER_MODE_SLEEP);
+ mutex_unlock(&data->mutex);
+
+ iio_device_unregister(indio_dev);
+
+ return ret;
+}
+EXPORT_SYMBOL(bma400_remove);
+
+MODULE_AUTHOR("Dan Robertson <dan@dlrobertson.com>");
+MODULE_DESCRIPTION("Bosch BMA400 triaxial acceleration sensor core");
+MODULE_LICENSE("GPL");
diff --git a/drivers/iio/accel/bma400_i2c.c b/drivers/iio/accel/bma400_i2c.c
new file mode 100644
index 000000000000..a1a9ac6a8d4c
--- /dev/null
+++ b/drivers/iio/accel/bma400_i2c.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * I2C IIO driver for Bosch BMA400 triaxial acceleration sensor.
+ *
+ * Copyright 2019 Dan Robertson <dan@dlrobertson.com>
+ *
+ * I2C address is either 0x14 or 0x15 depending on SDO
+ */
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "bma400.h"
+
+static int bma400_i2c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct regmap *regmap;
+
+ regmap = devm_regmap_init_i2c(client, &bma400_regmap_config);
+
+ if (IS_ERR(regmap)) {
+ dev_err(&client->dev, "failed to create regmap\n");
+ return PTR_ERR(regmap);
+ }
+
+ return bma400_probe(&client->dev, regmap, id->name);
+}
+
+static int bma400_i2c_remove(struct i2c_client *client)
+{
+ return bma400_remove(&client->dev);
+}
+
+static const struct i2c_device_id bma400_i2c_ids[] = {
+ { "bma400", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, bma400_i2c_ids);
+
+static const struct of_device_id bma400_of_i2c_match[] = {
+ { .compatible = "bosch,bma400" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, bma400_of_i2c_match);
+
+static struct i2c_driver bma400_i2c_driver = {
+ .driver = {
+ .name = "bma400",
+ .of_match_table = bma400_of_i2c_match,
+ },
+ .probe = bma400_i2c_probe,
+ .remove = bma400_i2c_remove,
+ .id_table = bma400_i2c_ids,
+};
+
+module_i2c_driver(bma400_i2c_driver);
+
+MODULE_AUTHOR("Dan Robertson <dan@dlrobertson.com>");
+MODULE_DESCRIPTION("Bosch BMA400 triaxial acceleration sensor (I2C)");
+MODULE_LICENSE("GPL");