Merge tag 'iio-for-5.6a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

First set of new device support, features and cleanups for IIO in the 5.6 cycle

New device support

* ad7091r5 ADC
  - New driver with follow up patch adding scale and vref support.
  - DT bindings
* ad7923
  - Support for ad7908, ad7918 and ad7928 added to driver.
* bma180
  - Support the BMA254 accelerometer. Required fairly substantial rework
    to allow for small differences between this an existing parts.
* bma400 accelerometer
  - New driver with follow up patch for regulator support.
  - DT bindings.
* asc dlhl60d
  - New driver support this range of pressure and temperature sensors.
  - DT bindings.
* ltc2496 ADC
  - New driver to support this ADC.
  - Split the existing LTC2497 driver generic component out and reuse.
  - DT bindings.
* parallax ping
  - New driver supporting ultrasonic and laser tof distance sensors.
  - Bindings for these sensors.

New features

* core
  - New char type for read_raw returns, used for thermocouple types.
  - Rename read_first_n callback to read.   The reasons behind the original
    naming are lost to the mists of time.
* ad799x
  - Allow pm_ops to disable device completely allowing regulator power down.
* bma180
  - Enable basic regulator support.
* dmaengine buffer
  - Report platform data alignment requirements via new ABI.
* max31856
  - Add option to set mains filter rejection frequency and document
    new in_temp_filter_notch_center_frequency ABI.
  - Add support for configuring HW averaging (oversampling ratio)
  - Add runtime configuration of thermocouple type and document new ABI.
* maxim-thermocouple
  - Add read only access to thermocouple type using new ABI, includes
    adding more specific compatibles to reflect which variant of the
    chip is being used.
* mpu6050
  - Provide option to support the PMU9150 in package magnetometer directly
    rather than via auxiliary bus.
* stm32_adc
  - Add overrun interrupt checks to detect if this happens.
* st_lsm6dsx
  - Enable the sensor-hub support for lsm6dsm. Includes various reworks to
    allow this.

Cleanups and minor fixes

* Subsystem wide
  - Tidy up indentation in Kconfig and fix alphabetical order of AD7091R5.
  - Drop linux/gpio.h and linux/of_gpio.h from drivers that don't use them.
* ad7266
  - Convert to GPIO descriptors.
* ad7303
  - Avoid a dance with checking if the regulator is supplied by just
    using the optional request interface.
* ad7887
  - Simplify channel specification assignment to enable adding more devices.
* ad7923
  - Drop some unused and largely pointless defines of BOB_N==N variety.
  - Tidy up checkpatch warnings.
  - Add missing of_device_id table.
* adf4350
  - Convert to GPIO descriptors.
* ak8975
  - Convert to GPIO descriptors.
* ADIS library and drivers
  - Expand scope of txrx_lock to cover all state and rename as state_lock
  - Add unlocked read / write to allow grouping of consecutive calls under
    single lock / unlock.
  - Add unlocked check_status, reset to allow grouping under single
    lock / unlock.
  - Remove remaining uses of core mlock for local state protection.
    mlock should never be used directly as it protects tightly defined
    core IIO device management state.
* adis16240
  - Enforce only supported SPI mode on driver load + add DT binding doc.
* atlas-ph-sensor
  - Rename to atlas-sensor given it now covers things beyond ph sensors.
* bma180
  - Use local dev variable to tidy up code.
  - Use c99 style explicity .member assignment to make driver more readable.
* bmp280
  - Drop ACPI support. No evidence this was used and appropriate ID is not
    registered.
  - Allow ACPI to bind device via PRP0001
* dmaengine buffer
  - Use dma_request_chan instead of dma_request_slave_channel_reason as that
    ABI is going away.
  - Add module info to avoid tainting the kernel.
* hts221
  - Avoid magic number defines when only used to fill structure elements
    that are self describing.
* lm3533
  - Drop a stray semicolon.
* max9611
  - Cleanup enum handling to be more resilient to future changes.
* mpu6050
  - Delete MPU9150 from supported SPI devices as doesn't provide SPI.
  - Select I2C_MUX again after kbuild issue fixed elsewhere.
* stm32-timer
  - Drop an unnecessary register update.
* ssp_sensors
  - Convert to GPIO descriptors.
* st_sensors
  - drop !CONFIG_ACPI defines as ACPI_PTR() will stop them being used
    anyway.
  - Make default platform data structures __maybe_unsued.
  - Fill in some missing kernel-doc function parameters.
* st_lsm6dsx
  - white space fixes.
  - Mark some constants that aren't always used as __maybe_unused.
  - Drop of ID table guards as they just pervent use under ACPI.
  - Switch to device properties to allow ACPI usage.
* st_uvis25
  - Drop acpi.h include as no ACPI APIs used.
* ti-ads1015
  - Drop legacy platform data as no one seems to be using it.
  - Use the device property API instead of OF specific.
* ti-ads7950
  - typo fix in error message.

* tag 'iio-for-5.6a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio: (99 commits)
  iio: accel: bma180: BMA254 support
  iio: pressure: bmp280: Allow device to be enumerated from ACPI
  iio: pressure: bmp280: Drop ACPI support
  dt-bindings: iio: adc: convert sd modulator to json-schema
  iio: buffer: rename 'read_first_n' callback to 'read'
  iio: buffer-dmaengine: Report buffer length requirements
  bindings: iio: pressure: Add documentation for dlh driver
  dt-bindings: Add asc vendor
  iio: pressure: Add driver for DLH pressure sensors
  iio: buffer-dmaengine: Add module information
  iio: accel: bma180: Use explicit member assignment
  iio: accel: bma180: Basic regulator support
  iio: accel: bma180: Add dev helper variable
  iio: imu: st_lsm6dsx: enable sensor-hub support for lsm6dsm
  iio: imu: st_lsm6dsx: rename st_lsm6dsx_shub_read_reg in st_lsm6dsx_shub_read_output
  iio: imu: st_lsm6dsx: check if shub_output reg is located in primary page
  iio: imu: st_lsm6dsx: check if pull_up is located in primary page
  iio: imu: st_lsm6dsx: check if master_enable is located in primary page
  iio: imu: st_lsm6dsx: export max num of slave devices in st_lsm6dsx_shub_settings
  iio: light: remove unneeded semicolon
  ...

8 files changed, 1216 insertions, 47 deletions

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index d4ef35aeb579..5d91a6dda894 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -89,13 +89,13 @@ config ADXL372_I2C
 	  module will be called adxl372_i2c.
 
 config BMA180
-	tristate "Bosch BMA180/BMA250 3-Axis Accelerometer Driver"
+	tristate "Bosch BMA180/BMA25x 3-Axis Accelerometer Driver"
 	depends on I2C
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 	help
 	  Say Y here if you want to build a driver for the Bosch BMA180 or
-	  BMA250 triaxial acceleration sensor.
+	  BMA25x triaxial acceleration sensor.
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called bma180.
@@ -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 if I2C is enabled.
+
+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/bma180.c b/drivers/iio/accel/bma180.c
index 1574e4604a4f..fcd91d5f05fd 100644
--- a/drivers/iio/accel/bma180.c
+++ b/drivers/iio/accel/bma180.c
@@ -9,6 +9,7 @@
  * SPI is not supported by driver
  * BMA180: 7-bit I2C slave address 0x40 or 0x41
  * BMA250: 7-bit I2C slave address 0x18 or 0x19
+ * BMA254: 7-bit I2C slave address 0x18 or 0x19
  */
 
 #include <linux/module.h>
@@ -18,6 +19,7 @@
 #include <linux/of_device.h>
 #include <linux/of.h>
 #include <linux/bitops.h>
+#include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/iio/iio.h>
@@ -33,17 +35,20 @@
 enum chip_ids {
 	BMA180,
 	BMA250,
+	BMA254,
 };
 
 struct bma180_data;
 
 struct bma180_part_info {
+	u8 chip_id;
 	const struct iio_chan_spec *channels;
 	unsigned int num_channels;
 	const int *scale_table;
 	unsigned int num_scales;
 	const int *bw_table;
 	unsigned int num_bw;
+	int center_temp;
 
 	u8 int_reset_reg, int_reset_mask;
 	u8 sleep_reg, sleep_mask;
@@ -51,6 +56,7 @@ struct bma180_part_info {
 	u8 scale_reg, scale_mask;
 	u8 power_reg, power_mask, lowpower_val;
 	u8 int_enable_reg, int_enable_mask;
+	u8 int_map_reg, int_enable_dataready_int1_mask;
 	u8 softreset_reg;
 
 	int (*chip_config)(struct bma180_data *data);
@@ -89,6 +95,8 @@ struct bma180_part_info {
 #define BMA180_RESET_VAL	0xb6
 
 #define BMA180_ID_REG_VAL	0x03
+#define BMA250_ID_REG_VAL	0x03
+#define BMA254_ID_REG_VAL	0xfa /* 250 decimal */
 
 /* Chip power modes */
 #define BMA180_LOW_POWER	0x03
@@ -109,7 +117,26 @@ struct bma180_part_info {
 #define BMA250_INT1_DATA_MASK	BIT(0)
 #define BMA250_INT_RESET_MASK	BIT(7) /* Reset pending interrupts */
 
+#define BMA254_RANGE_REG	0x0f
+#define BMA254_BW_REG		0x10
+#define BMA254_POWER_REG	0x11
+#define BMA254_RESET_REG	0x14
+#define BMA254_INT_ENABLE_REG	0x17
+#define BMA254_INT_MAP_REG	0x1a
+#define BMA254_INT_RESET_REG	0x21
+
+#define BMA254_RANGE_MASK	GENMASK(3, 0) /* Range of accel values */
+#define BMA254_BW_MASK		GENMASK(4, 0) /* Accel bandwidth */
+#define BMA254_SUSPEND_MASK	BIT(7) /* chip will sleep */
+#define BMA254_LOWPOWER_MASK	BIT(6)
+#define BMA254_DATA_INTEN_MASK	BIT(4)
+#define BMA254_INT2_DATA_MASK	BIT(7)
+#define BMA254_INT1_DATA_MASK	BIT(0)
+#define BMA254_INT_RESET_MASK	BIT(7) /* Reset pending interrupts */
+
 struct bma180_data {
+	struct regulator *vdd_supply;
+	struct regulator *vddio_supply;
 	struct i2c_client *client;
 	struct iio_trigger *trig;
 	const struct bma180_part_info *part_info;
@@ -132,8 +159,8 @@ enum bma180_chan {
 static int bma180_bw_table[] = { 10, 20, 40, 75, 150, 300 }; /* Hz */
 static int bma180_scale_table[] = { 1275, 1863, 2452, 3727, 4903, 9709, 19417 };
 
-static int bma250_bw_table[] = { 8, 16, 31, 63, 125, 250 }; /* Hz */
-static int bma250_scale_table[] = { 0, 0, 0, 38344, 0, 76590, 0, 0, 153180, 0,
+static int bma25x_bw_table[] = { 8, 16, 31, 63, 125, 250 }; /* Hz */
+static int bma25x_scale_table[] = { 0, 0, 0, 38344, 0, 76590, 0, 0, 153180, 0,
 	0, 0, 306458 };
 
 static int bma180_get_data_reg(struct bma180_data *data, enum bma180_chan chan)
@@ -307,8 +334,11 @@ static int bma180_chip_init(struct bma180_data *data)
 
 	if (ret < 0)
 		return ret;
-	if (ret != BMA180_ID_REG_VAL)
+	if (ret != data->part_info->chip_id) {
+		dev_err(&data->client->dev, "wrong chip ID %d expected %d\n",
+			ret, data->part_info->chip_id);
 		return -ENODEV;
+	}
 
 	ret = bma180_soft_reset(data);
 	if (ret)
@@ -355,7 +385,7 @@ err:
 	return ret;
 }
 
-static int bma250_chip_config(struct bma180_data *data)
+static int bma25x_chip_config(struct bma180_data *data)
 {
 	int ret = bma180_chip_init(data);
 
@@ -367,8 +397,12 @@ static int bma250_chip_config(struct bma180_data *data)
 	ret = bma180_set_scale(data, 38344); /* 2 G */
 	if (ret)
 		goto err;
-	ret = bma180_set_bits(data, BMA250_INT_MAP_REG,
-		BMA250_INT1_DATA_MASK, 1);
+	/*
+	 * This enables dataready interrupt on the INT1 pin
+	 * FIXME: support using the INT2 pin
+	 */
+	ret = bma180_set_bits(data, data->part_info->int_map_reg,
+		data->part_info->int_enable_dataready_int1_mask, 1);
 	if (ret)
 		goto err;
 
@@ -394,7 +428,7 @@ err:
 	dev_err(&data->client->dev, "failed to disable the chip\n");
 }
 
-static void bma250_chip_disable(struct bma180_data *data)
+static void bma25x_chip_disable(struct bma180_data *data)
 {
 	if (bma180_set_new_data_intr_state(data, false))
 		goto err;
@@ -497,7 +531,7 @@ static int bma180_read_raw(struct iio_dev *indio_dev,
 			return -EINVAL;
 		}
 	case IIO_CHAN_INFO_OFFSET:
-		*val = 48; /* 0 LSB @ 24 degree C */
+		*val = data->part_info->center_temp;
 		return IIO_VAL_INT;
 	default:
 		return -EINVAL;
@@ -627,34 +661,96 @@ static const struct iio_chan_spec bma250_channels[] = {
 	IIO_CHAN_SOFT_TIMESTAMP(4),
 };
 
+static const struct iio_chan_spec bma254_channels[] = {
+	BMA180_ACC_CHANNEL(X, 12),
+	BMA180_ACC_CHANNEL(Y, 12),
+	BMA180_ACC_CHANNEL(Z, 12),
+	BMA180_TEMP_CHANNEL,
+	IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
 static const struct bma180_part_info bma180_part_info[] = {
 	[BMA180] = {
-		bma180_channels, ARRAY_SIZE(bma180_channels),
-		bma180_scale_table, ARRAY_SIZE(bma180_scale_table),
-		bma180_bw_table, ARRAY_SIZE(bma180_bw_table),
-		BMA180_CTRL_REG0, BMA180_RESET_INT,
-		BMA180_CTRL_REG0, BMA180_SLEEP,
-		BMA180_BW_TCS, BMA180_BW,
-		BMA180_OFFSET_LSB1, BMA180_RANGE,
-		BMA180_TCO_Z, BMA180_MODE_CONFIG, BMA180_LOW_POWER,
-		BMA180_CTRL_REG3, BMA180_NEW_DATA_INT,
-		BMA180_RESET,
-		bma180_chip_config,
-		bma180_chip_disable,
+		.chip_id = BMA180_ID_REG_VAL,
+		.channels = bma180_channels,
+		.num_channels = ARRAY_SIZE(bma180_channels),
+		.scale_table = bma180_scale_table,
+		.num_scales = ARRAY_SIZE(bma180_scale_table),
+		.bw_table = bma180_bw_table,
+		.num_bw = ARRAY_SIZE(bma180_bw_table),
+		.center_temp = 48, /* 0 LSB @ 24 degree C */
+		.int_reset_reg = BMA180_CTRL_REG0,
+		.int_reset_mask = BMA180_RESET_INT,
+		.sleep_reg = BMA180_CTRL_REG0,
+		.sleep_mask = BMA180_SLEEP,
+		.bw_reg = BMA180_BW_TCS,
+		.bw_mask = BMA180_BW,
+		.scale_reg = BMA180_OFFSET_LSB1,
+		.scale_mask = BMA180_RANGE,
+		.power_reg = BMA180_TCO_Z,
+		.power_mask = BMA180_MODE_CONFIG,
+		.lowpower_val = BMA180_LOW_POWER,
+		.int_enable_reg = BMA180_CTRL_REG3,
+		.int_enable_mask = BMA180_NEW_DATA_INT,
+		.softreset_reg = BMA180_RESET,
+		.chip_config = bma180_chip_config,
+		.chip_disable = bma180_chip_disable,
 	},
 	[BMA250] = {
-		bma250_channels, ARRAY_SIZE(bma250_channels),
-		bma250_scale_table, ARRAY_SIZE(bma250_scale_table),
-		bma250_bw_table, ARRAY_SIZE(bma250_bw_table),
-		BMA250_INT_RESET_REG, BMA250_INT_RESET_MASK,
-		BMA250_POWER_REG, BMA250_SUSPEND_MASK,
-		BMA250_BW_REG, BMA250_BW_MASK,
-		BMA250_RANGE_REG, BMA250_RANGE_MASK,
-		BMA250_POWER_REG, BMA250_LOWPOWER_MASK, 1,
-		BMA250_INT_ENABLE_REG, BMA250_DATA_INTEN_MASK,
-		BMA250_RESET_REG,
-		bma250_chip_config,
-		bma250_chip_disable,
+		.chip_id = BMA250_ID_REG_VAL,
+		.channels = bma250_channels,
+		.num_channels = ARRAY_SIZE(bma250_channels),
+		.scale_table = bma25x_scale_table,
+		.num_scales = ARRAY_SIZE(bma25x_scale_table),
+		.bw_table = bma25x_bw_table,
+		.num_bw = ARRAY_SIZE(bma25x_bw_table),
+		.center_temp = 48, /* 0 LSB @ 24 degree C */
+		.int_reset_reg = BMA250_INT_RESET_REG,
+		.int_reset_mask = BMA250_INT_RESET_MASK,
+		.sleep_reg = BMA250_POWER_REG,
+		.sleep_mask = BMA250_SUSPEND_MASK,
+		.bw_reg = BMA250_BW_REG,
+		.bw_mask = BMA250_BW_MASK,
+		.scale_reg = BMA250_RANGE_REG,
+		.scale_mask = BMA250_RANGE_MASK,
+		.power_reg = BMA250_POWER_REG,
+		.power_mask = BMA250_LOWPOWER_MASK,
+		.lowpower_val = 1,
+		.int_enable_reg = BMA250_INT_ENABLE_REG,
+		.int_enable_mask = BMA250_DATA_INTEN_MASK,
+		.int_map_reg = BMA250_INT_MAP_REG,
+		.int_enable_dataready_int1_mask = BMA250_INT1_DATA_MASK,
+		.softreset_reg = BMA250_RESET_REG,
+		.chip_config = bma25x_chip_config,
+		.chip_disable = bma25x_chip_disable,
+	},
+	[BMA254] = {
+		.chip_id = BMA254_ID_REG_VAL,
+		.channels = bma254_channels,
+		.num_channels = ARRAY_SIZE(bma254_channels),
+		.scale_table = bma25x_scale_table,
+		.num_scales = ARRAY_SIZE(bma25x_scale_table),
+		.bw_table = bma25x_bw_table,
+		.num_bw = ARRAY_SIZE(bma25x_bw_table),
+		.center_temp = 46, /* 0 LSB @ 23 degree C */
+		.int_reset_reg = BMA254_INT_RESET_REG,
+		.int_reset_mask = BMA254_INT_RESET_MASK,
+		.sleep_reg = BMA254_POWER_REG,
+		.sleep_mask = BMA254_SUSPEND_MASK,
+		.bw_reg = BMA254_BW_REG,
+		.bw_mask = BMA254_BW_MASK,
+		.scale_reg = BMA254_RANGE_REG,
+		.scale_mask = BMA254_RANGE_MASK,
+		.power_reg = BMA254_POWER_REG,
+		.power_mask = BMA254_LOWPOWER_MASK,
+		.lowpower_val = 1,
+		.int_enable_reg = BMA254_INT_ENABLE_REG,
+		.int_enable_mask = BMA254_DATA_INTEN_MASK,
+		.int_map_reg = BMA254_INT_MAP_REG,
+		.int_enable_dataready_int1_mask = BMA254_INT1_DATA_MASK,
+		.softreset_reg = BMA254_RESET_REG,
+		.chip_config = bma25x_chip_config,
+		.chip_disable = bma25x_chip_disable,
 	},
 };
 
@@ -712,12 +808,13 @@ static const struct iio_trigger_ops bma180_trigger_ops = {
 static int bma180_probe(struct i2c_client *client,
 		const struct i2c_device_id *id)
 {
+	struct device *dev = &client->dev;
 	struct bma180_data *data;
 	struct iio_dev *indio_dev;
 	enum chip_ids chip;
 	int ret;
 
-	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;
 
@@ -725,22 +822,56 @@ static int bma180_probe(struct i2c_client *client,
 	i2c_set_clientdata(client, indio_dev);
 	data->client = client;
 	if (client->dev.of_node)
-		chip = (enum chip_ids)of_device_get_match_data(&client->dev);
+		chip = (enum chip_ids)of_device_get_match_data(dev);
 	else
 		chip = id->driver_data;
 	data->part_info = &bma180_part_info[chip];
 
-	ret = iio_read_mount_matrix(&client->dev, "mount-matrix",
+	ret = iio_read_mount_matrix(dev, "mount-matrix",
 				&data->orientation);
 	if (ret)
 		return ret;
 
+	data->vdd_supply = devm_regulator_get(dev, "vdd");
+	if (IS_ERR(data->vdd_supply)) {
+		if (PTR_ERR(data->vdd_supply) != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get vdd regulator %d\n",
+				(int)PTR_ERR(data->vdd_supply));
+		return PTR_ERR(data->vdd_supply);
+	}
+	data->vddio_supply = devm_regulator_get(dev, "vddio");
+	if (IS_ERR(data->vddio_supply)) {
+		if (PTR_ERR(data->vddio_supply) != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get vddio regulator %d\n",
+				(int)PTR_ERR(data->vddio_supply));
+		return PTR_ERR(data->vddio_supply);
+	}
+	/* Typical voltage 2.4V these are min and max */
+	ret = regulator_set_voltage(data->vdd_supply, 1620000, 3600000);
+	if (ret)
+		return ret;
+	ret = regulator_set_voltage(data->vddio_supply, 1200000, 3600000);
+	if (ret)
+		return ret;
+	ret = regulator_enable(data->vdd_supply);
+	if (ret) {
+		dev_err(dev, "Failed to enable vdd regulator: %d\n", ret);
+		return ret;
+	}
+	ret = regulator_enable(data->vddio_supply);
+	if (ret) {
+		dev_err(dev, "Failed to enable vddio regulator: %d\n", ret);
+		goto err_disable_vdd;
+	}
+	/* Wait to make sure we started up properly (3 ms at least) */
+	usleep_range(3000, 5000);
+
 	ret = data->part_info->chip_config(data);
 	if (ret < 0)
 		goto err_chip_disable;
 
 	mutex_init(&data->mutex);
-	indio_dev->dev.parent = &client->dev;
+	indio_dev->dev.parent = dev;
 	indio_dev->channels = data->part_info->channels;
 	indio_dev->num_channels = data->part_info->num_channels;
 	indio_dev->name = id->name;
@@ -755,15 +886,15 @@ static int bma180_probe(struct i2c_client *client,
 			goto err_chip_disable;
 		}
 
-		ret = devm_request_irq(&client->dev, client->irq,
+		ret = devm_request_irq(dev, client->irq,
 			iio_trigger_generic_data_rdy_poll, IRQF_TRIGGER_RISING,
 			"bma180_event", data->trig);
 		if (ret) {
-			dev_err(&client->dev, "unable to request IRQ\n");
+			dev_err(dev, "unable to request IRQ\n");
 			goto err_trigger_free;
 		}
 
-		data->trig->dev.parent = &client->dev;
+		data->trig->dev.parent = dev;
 		data->trig->ops = &bma180_trigger_ops;
 		iio_trigger_set_drvdata(data->trig, indio_dev);
 		indio_dev->trig = iio_trigger_get(data->trig);
@@ -776,13 +907,13 @@ static int bma180_probe(struct i2c_client *client,
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
 			bma180_trigger_handler, NULL);
 	if (ret < 0) {
-		dev_err(&client->dev, "unable to setup iio triggered buffer\n");
+		dev_err(dev, "unable to setup iio triggered buffer\n");
 		goto err_trigger_unregister;
 	}
 
 	ret = iio_device_register(indio_dev);
 	if (ret < 0) {
-		dev_err(&client->dev, "unable to register iio device\n");
+		dev_err(dev, "unable to register iio device\n");
 		goto err_buffer_cleanup;
 	}
 
@@ -797,6 +928,9 @@ err_trigger_free:
 	iio_trigger_free(data->trig);
 err_chip_disable:
 	data->part_info->chip_disable(data);
+	regulator_disable(data->vddio_supply);
+err_disable_vdd:
+	regulator_disable(data->vdd_supply);
 
 	return ret;
 }
@@ -816,6 +950,8 @@ static int bma180_remove(struct i2c_client *client)
 	mutex_lock(&data->mutex);
 	data->part_info->chip_disable(data);
 	mutex_unlock(&data->mutex);
+	regulator_disable(data->vddio_supply);
+	regulator_disable(data->vdd_supply);
 
 	return 0;
 }
@@ -856,6 +992,7 @@ static SIMPLE_DEV_PM_OPS(bma180_pm_ops, bma180_suspend, bma180_resume);
 static const struct i2c_device_id bma180_ids[] = {
 	{ "bma180", BMA180 },
 	{ "bma250", BMA250 },
+	{ "bma254", BMA254 },
 	{ }
 };
 
@@ -870,6 +1007,10 @@ static const struct of_device_id bma180_of_match[] = {
 		.compatible = "bosch,bma250",
 		.data = (void *)BMA250
 	},
+	{
+		.compatible = "bosch,bma254",
+		.data = (void *)BMA254
+	},
 	{ }
 };
 MODULE_DEVICE_TABLE(of, bma180_of_match);
@@ -889,5 +1030,5 @@ module_i2c_driver(bma180_driver);
 
 MODULE_AUTHOR("Kravchenko Oleksandr <x0199363@ti.com>");
 MODULE_AUTHOR("Texas Instruments, Inc.");
-MODULE_DESCRIPTION("Bosch BMA180/BMA250 triaxial acceleration sensor");
+MODULE_DESCRIPTION("Bosch BMA180/BMA25x triaxial acceleration sensor");
 MODULE_LICENSE("GPL");
diff --git a/drivers/iio/accel/bma400.h b/drivers/iio/accel/bma400.h
new file mode 100644
index 000000000000..5ad10db9819f
--- /dev/null
+++ b/drivers/iio/accel/bma400.h
@@ -0,0 +1,99 @@
+/* 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         5
+#define BMA400_NP_OSR_SHIFT         4
+#define BMA400_SCALE_SHIFT          6
+
+#define BMA400_TWO_BITS_MASK        GENMASK(1, 0)
+#define BMA400_LP_OSR_MASK          GENMASK(6, 5)
+#define BMA400_NP_OSR_MASK          GENMASK(5, 4)
+#define BMA400_ACC_ODR_MASK         GENMASK(3, 0)
+#define BMA400_ACC_SCALE_MASK       GENMASK(7, 6)
+
+#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            306864
+
+#define BMA400_NUM_REGULATORS       2
+#define BMA400_VDD_REGULATOR        0
+#define BMA400_VDDIO_REGULATOR      1
+
+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..ab4a158b35af
--- /dev/null
+++ b/drivers/iio/accel/bma400_core.c
@@ -0,0 +1,852 @@
+// 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 <linux/regulator/consumer.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 regmap *regmap;
+	struct regulator_bulk_data regulators[BMA400_NUM_REGULATORS];
+	struct mutex mutex; /* data register lock */
+	struct iio_mount_matrix orientation;
+	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)
+		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)
+		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)
+			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_MAX_HZ)
+			return -EINVAL;
+
+		/* Note this works because MIN_WHOLE_HZ is odd */
+		idx = __ffs(hz);
+
+		if (hz >> idx != BMA400_ACC_ODR_MIN_WHOLE_HZ)
+			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)
+		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)
+		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) {
+			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) {
+			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 -EINVAL;
+	}
+}
+
+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)
+			return ret;
+
+		ret = regmap_write(data->regmap, BMA400_ACC_CONFIG0_REG,
+				   (acc_config & ~BMA400_LP_OSR_MASK) |
+				   (val << BMA400_LP_OSR_SHIFT));
+		if (ret) {
+			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)
+			return ret;
+
+		ret = regmap_write(data->regmap, BMA400_ACC_CONFIG1_REG,
+				   (acc_config & ~BMA400_NP_OSR_MASK) |
+				   (val << BMA400_NP_OSR_SHIFT));
+		if (ret) {
+			dev_err(data->dev, "Failed to write out OSR\n");
+			return ret;
+		}
+
+		data->oversampling_ratio = val;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+	return ret;
+}
+
+static int bma400_accel_scale_to_raw(struct bma400_data *data,
+				     unsigned int val)
+{
+	int raw;
+
+	if (val == 0)
+		return -EINVAL;
+
+	/* Note this works because BMA400_SCALE_MIN is odd */
+	raw = __ffs(val);
+
+	if (val >> raw != BMA400_SCALE_MIN)
+		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)
+		return ret;
+
+	raw_scale = (val & BMA400_ACC_SCALE_MASK) >> BMA400_SCALE_SHIFT;
+	if (raw_scale > BMA400_TWO_BITS_MASK)
+		return -EINVAL;
+
+	data->scale = BMA400_SCALE_MIN << raw_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)
+		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)
+		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) {
+		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)
+		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) {
+		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_scales[i + 1] = BMA400_SCALE_MIN << raw;
+	}
+}
+
+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) {
+		dev_err(data->dev, "Failed to read chip id register\n");
+		goto out;
+	}
+
+	if (val != BMA400_ID_REG_VAL) {
+		dev_err(data->dev, "Chip ID mismatch\n");
+		ret = -ENODEV;
+		goto out;
+	}
+
+	data->regulators[BMA400_VDD_REGULATOR].supply = "vdd";
+	data->regulators[BMA400_VDDIO_REGULATOR].supply = "vddio";
+	ret = devm_regulator_bulk_get(data->dev,
+				      ARRAY_SIZE(data->regulators),
+				      data->regulators);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(data->dev,
+				"Failed to get regulators: %d\n",
+				ret);
+
+		goto out;
+	}
+	ret = regulator_bulk_enable(ARRAY_SIZE(data->regulators),
+				    data->regulators);
+	if (ret) {
+		dev_err(data->dev, "Failed to enable regulators: %d\n",
+			ret);
+		goto out;
+	}
+
+	ret = bma400_get_power_mode(data);
+	if (ret) {
+		dev_err(data->dev, "Failed to get the initial power-mode\n");
+		goto err_reg_disable;
+	}
+
+	if (data->power_mode != POWER_MODE_NORMAL) {
+		ret = bma400_set_power_mode(data, POWER_MODE_NORMAL);
+		if (ret) {
+			dev_err(data->dev, "Failed to wake up the device\n");
+			goto err_reg_disable;
+		}
+		/*
+		 * 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)
+		goto err_reg_disable;
+
+	ret = bma400_get_accel_oversampling_ratio(data);
+	if (ret)
+		goto err_reg_disable;
+
+	ret = bma400_get_accel_scale(data);
+	if (ret)
+		goto err_reg_disable;
+
+	/*
+	 * 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);
+
+err_reg_disable:
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators),
+			       data->regulators);
+out:
+	return ret;
+}
+
+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)
+			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)
+		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);
+
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators),
+			       data->regulators);
+
+	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..9dcb7cc9996e
--- /dev/null
+++ b/drivers/iio/accel/bma400_i2c.c
@@ -0,0 +1,61 @@
+// 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");
diff --git a/drivers/iio/accel/st_accel.h b/drivers/iio/accel/st_accel.h
index af09943f38c9..5b13e293cade 100644
--- a/drivers/iio/accel/st_accel.h
+++ b/drivers/iio/accel/st_accel.h
@@ -64,7 +64,7 @@ enum st_accel_type {
 * struct st_sensors_platform_data - default accel platform data
 * @drdy_int_pin: default accel DRDY is available on INT1 pin.
 */
-static const struct st_sensors_platform_data default_accel_pdata = {
+static __maybe_unused const struct st_sensors_platform_data default_accel_pdata = {
 	.drdy_int_pin = 1,
 };
 
diff --git a/drivers/iio/accel/st_accel_i2c.c b/drivers/iio/accel/st_accel_i2c.c
index 50fa0fc32baa..0f4aef5448e7 100644
--- a/drivers/iio/accel/st_accel_i2c.c
+++ b/drivers/iio/accel/st_accel_i2c.c
@@ -119,8 +119,6 @@ static const struct acpi_device_id st_accel_acpi_match[] = {
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, st_accel_acpi_match);
-#else
-#define st_accel_acpi_match NULL
 #endif
 
 static const struct i2c_device_id st_accel_id_table[] = {