[PATCH v2 2/2] iio: accel: Add driver support for ADXL355

[Puranjay Mohan <puranjay12@gmail.com>]

ADXL355 is 3-axis MEMS Accelerometer. It offers low noise density,
low 0g offset drift, low power with selectable measurement ranges.
It also features programmable high-pass and low-pass filters.

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/adxl354_adxl355.pdf
Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
---
 MAINTAINERS                      |   7 +
 drivers/iio/accel/Kconfig        |  29 ++
 drivers/iio/accel/Makefile       |   3 +
 drivers/iio/accel/adxl355.h      |  79 +++++
 drivers/iio/accel/adxl355_core.c | 536 +++++++++++++++++++++++++++++++
 drivers/iio/accel/adxl355_i2c.c  |  63 ++++
 drivers/iio/accel/adxl355_spi.c  |  66 ++++
 7 files changed, 783 insertions(+)
 create mode 100644 drivers/iio/accel/adxl355.h
 create mode 100644 drivers/iio/accel/adxl355_core.c
 create mode 100644 drivers/iio/accel/adxl355_i2c.c
 create mode 100644 drivers/iio/accel/adxl355_spi.c

diff --git a/MAINTAINERS b/MAINTAINERS
index bd7aff0c1..461f2a192 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -586,6 +586,13 @@ W:	http://ez.analog.com/community/linux-device-drivers
 F:	Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml
 F:	drivers/input/misc/adxl34x.c
 
+ADXL355 THREE-AXIS DIGITAL ACCELEROMETER DRIVER
+M:	Puranjay Mohan <puranjay12@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Supported
+F:	drivers/iio/accel/adxl34x.c
+F:	Documentation/devicetree/bindings/iio/accel/adi,adxl355.yaml
+
 ADXL372 THREE-AXIS DIGITAL ACCELEROMETER DRIVER
 M:	Michael Hennerich <michael.hennerich@analog.com>
 S:	Supported
diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index cceda3cec..9a65353a4 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -61,6 +61,35 @@ config ADXL345_SPI
 	  will be called adxl345_spi and you will also get adxl345_core
 	  for the core module.
 
+config ADXL355
+	tristate
+
+config ADXL355_I2C
+	tristate "Analog Devices ADXL355 3-Axis Digital Accelerometer I2C Driver"
+	depends on I2C
+	select ADXL355
+	select REGMAP_I2C
+	help
+	  Say Y here if you want to build support for the Analog Devices
+	  ADXL355 3-axis digital accelerometer.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called adxl355_i2c and you will also get adxl355_core
+	  for the core module.
+
+config ADXL355_SPI
+	tristate "Analog Devices ADXL355 3-Axis Digital Accelerometer SPI Driver"
+	depends on SPI
+	select ADXL355
+	select REGMAP_SPI
+	help
+	  Say Y here if you want to build support for the Analog Devices
+	  ADXL355 3-axis digital accelerometer.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called adxl355_spi and you will also get adxl355_core
+	  for the core module.
+
 config ADXL372
 	tristate
 	select IIO_BUFFER
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 32cd1342a..0e4721d2d 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -9,6 +9,9 @@ obj-$(CONFIG_ADIS16209) += adis16209.o
 obj-$(CONFIG_ADXL345) += adxl345_core.o
 obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
 obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o
+obj-$(CONFIG_ADXL355) += adxl355_core.o
+obj-$(CONFIG_ADXL355_I2C) += adxl355_i2c.o
+obj-$(CONFIG_ADXL355_SPI) += adxl355_spi.o
 obj-$(CONFIG_ADXL372) += adxl372.o
 obj-$(CONFIG_ADXL372_I2C) += adxl372_i2c.o
 obj-$(CONFIG_ADXL372_SPI) += adxl372_spi.o
diff --git a/drivers/iio/accel/adxl355.h b/drivers/iio/accel/adxl355.h
new file mode 100644
index 000000000..e0b1e697f
--- /dev/null
+++ b/drivers/iio/accel/adxl355.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * ADXL355 3-Axis Digital Accelerometer
+ *
+ * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
+ */
+
+#ifndef _ADXL355_H_
+#define _ADXL355_H_
+
+#include <linux/regmap.h>
+
+/* ADXL355 Register Definitions */
+#define ADXL355_DEVID_AD	0x00
+#define ADXL355_DEVID_MST	0x01
+#define ADXL355_PARTID		0x02
+#define ADXL355_REVID		0x03
+#define ADXL355_STATUS		0x04
+#define ADXL355_FIFO_ENTRIES	0x05
+#define ADXL355_TEMP2		0x06
+#define ADXL355_XDATA3		0x08
+#define ADXL355_YDATA3		0x0B
+#define ADXL355_ZDATA3		0x0E
+#define ADXL355_FIFO_DATA	0x11
+#define ADXL355_OFFSET_X_H	0x1E
+#define ADXL355_OFFSET_Y_H	0x20
+#define ADXL355_OFFSET_Z_H	0x22
+#define ADXL355_ACT_EN		0x24
+#define ADXL355_ACT_THRESH_H	0x25
+#define ADXL355_ACT_THRESH_L	0x26
+#define ADXL355_ACT_COUNT	0x27
+#define ADXL355_FILTER		0x28
+#define ADXL355_FIFO_SAMPLES	0x29
+#define ADXL355_INT_MAP		0x2A
+#define ADXL355_SYNC		0x2B
+#define ADXL355_RANGE		0x2C
+#define ADXL355_POWER_CTL	0x2D
+#define ADXL355_SELF_TEST	0x2E
+#define ADXL355_RESET		0x2F
+
+#define ADXL355_DEVID_AD_VAL	0xAD
+#define ADXL355_DEVID_MST_VAL	0x1D
+#define ADXL355_PARTID_VAL	0xED
+#define ADXL355_REVID_VAL	0x01
+#define ADXL355_RESET_CODE	0x52
+
+#define ADXL355_POWER_CTL_MODE_MSK	GENMASK(1, 0)
+
+#define ADXL355_FILTER_ODR_MSK			GENMASK(3, 0)
+#define ADXL355_FILTER_ODR_MODE(x)		((x) & 0xF)
+#define ADXL355_FILTER_HPF_MSK			GENMASK(6, 4)
+#define ADXL355_FILTER_HPF_MODE(x)		(((x) & 0x7) << 4)
+
+/*
+ * The datasheet defines an intercept of 1885 LSB at 25 degC
+ * and a slope of -9.05 LSB/C. The following formula can be used to find the
+ * temperature:
+ * Temp = ((RAW - 1885)/(-9.05)) + 25 but this doesn't follow the format of
+ * the IIO which is Temp = (RAW + OFFSET) * SCALE. Hence using some rearranging
+ * we get the scale as -110.49723 and offset as -2111.25
+ */
+#define TEMP_SCALE_VAL -110
+#define TEMP_SCALE_VAL2 497238
+#define TEMP_OFFSET_VAL -2111
+#define TEMP_OFFSET_VAL2 250000
+
+/*
+ * At +/- 2g with 20-bit resolution, scale is given in datasheet as
+ * 3.9ug/LSB = 0.0000039 * 9.80665 = 0.00003824593 m/s^2
+ */
+#define ADXL355_NSCALE	38245
+
+extern const struct regmap_access_table adxl355_readable_regs_tbl;
+
+extern const struct regmap_access_table adxl355_writeable_regs_tbl;
+
+int adxl355_core_probe(struct device *dev, struct regmap *regmap,
+		       const char *name);
+#endif /* _ADXL355_H_ */
diff --git a/drivers/iio/accel/adxl355_core.c b/drivers/iio/accel/adxl355_core.c
new file mode 100644
index 000000000..fa0370d41
--- /dev/null
+++ b/drivers/iio/accel/adxl355_core.c
@@ -0,0 +1,536 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ADXL355 3-Axis Digital Accelerometer IIO core driver
+ *
+ * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
+ *
+ * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/adxl354_adxl355.pdf
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/limits.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "adxl355.h"
+
+static const struct regmap_range adxl355_read_reg_range[] = {
+	regmap_reg_range(ADXL355_DEVID_AD, ADXL355_FIFO_DATA),
+	regmap_reg_range(ADXL355_OFFSET_X_H, ADXL355_SELF_TEST)
+};
+
+const struct regmap_access_table adxl355_readable_regs_tbl = {
+	.yes_ranges = adxl355_read_reg_range,
+	.n_yes_ranges = ARRAY_SIZE(adxl355_read_reg_range),
+};
+EXPORT_SYMBOL_GPL(adxl355_readable_regs_tbl);
+
+static const struct regmap_range adxl355_write_reg_range[] = {
+	regmap_reg_range(ADXL355_OFFSET_X_H, ADXL355_RESET)
+};
+
+const struct regmap_access_table adxl355_writeable_regs_tbl = {
+	.yes_ranges = adxl355_write_reg_range,
+	.n_yes_ranges = ARRAY_SIZE(adxl355_write_reg_range),
+};
+EXPORT_SYMBOL_GPL(adxl355_writeable_regs_tbl);
+
+enum adxl355_op_mode {
+	ADXL355_MEASUREMENT,
+	ADXL355_STANDBY,
+	ADXL355_TEMP_OFF
+};
+
+enum adxl355_odr {
+	ADXL355_ODR_4000HZ,
+	ADXL355_ODR_2000HZ,
+	ADXL355_ODR_1000HZ,
+	ADXL355_ODR_500HZ,
+	ADXL355_ODR_250HZ,
+	ADXL355_ODR_125HZ,
+	ADXL355_ODR_62_5HZ,
+	ADXL355_ODR_31_25HZ,
+	ADXL355_ODR_15_625HZ,
+	ADXL355_ODR_7_813HZ,
+	ADXL355_ODR_3_906HZ
+};
+
+enum adxl355_hpf_3db {
+	ADXL355_HPF_OFF,
+	ADXL355_HPF_24_7,
+	ADXL355_HPF_6_2084,
+	ADXL355_HPF_1_5545,
+	ADXL355_HPF_0_3862,
+	ADXL355_HPF_0_0954,
+	ADXL355_HPF_0_0238
+};
+
+static const int adxl355_odr_table[][2] = {
+	[0] = {4000, 0},
+	[1] = {2000, 0},
+	[2] = {1000, 0},
+	[3] = {500, 0},
+	[4] = {250, 0},
+	[5] = {125, 0},
+	[6] = {62, 500000},
+	[7] = {31, 250000},
+	[8] = {15, 625000},
+	[9] = {7, 813000},
+	[10] = {3, 906000}
+};
+
+static const int adxl355_hpf_3db_multipliers[] = {
+	0,
+	247000,
+	62084,
+	15545,
+	3862,
+	954,
+	238
+};
+
+struct adxl355_data {
+	struct regmap *regmap;
+	struct device *dev;
+	struct mutex lock; /* lock to protect op_mode */
+	enum adxl355_op_mode op_mode;
+	enum adxl355_odr odr;
+	enum adxl355_hpf_3db hpf_3db;
+	int x_calibbias;
+	int y_calibbias;
+	int z_calibbias;
+	int adxl355_hpf_3db_table[7][2];
+};
+
+static int adxl355_set_op_mode(struct adxl355_data *data,
+			       enum adxl355_op_mode op_mode)
+{
+	int ret;
+
+	if (data->op_mode == op_mode)
+		return 0;
+
+	ret = regmap_update_bits(data->regmap, ADXL355_POWER_CTL,
+				 ADXL355_POWER_CTL_MODE_MSK, op_mode);
+	if (ret < 0)
+		return ret;
+
+	data->op_mode = op_mode;
+
+	return ret;
+}
+
+static void adxl355_fill_3db_frequency_table(struct adxl355_data *data)
+{
+	int i;
+	u64 rem;
+	u64 div;
+	u32 multiplier;
+	u64 odr = mul_u64_u32_shr(adxl355_odr_table[data->odr][0], 1000000, 0) +
+					adxl355_odr_table[data->odr][1];
+
+	for (i = 0; i < ARRAY_SIZE(adxl355_hpf_3db_multipliers); i++) {
+		multiplier = adxl355_hpf_3db_multipliers[i];
+		div = div64_u64_rem(mul_u64_u32_shr(odr, multiplier, 0),
+				    100000000000000UL, &rem);
+
+		data->adxl355_hpf_3db_table[i][0] = div;
+		data->adxl355_hpf_3db_table[i][1] = div_u64(rem, 100000000);
+	}
+}
+
+static int adxl355_setup(struct adxl355_data *data)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(data->regmap, ADXL355_DEVID_AD, &regval);
+	if (ret < 0)
+		return ret;
+
+	if (regval != ADXL355_DEVID_AD_VAL) {
+		dev_err(data->dev, "Invalid ADI ID 0x%02x\n", regval);
+		return -ENODEV;
+	}
+
+	ret = regmap_read(data->regmap, ADXL355_DEVID_MST, &regval);
+	if (ret < 0)
+		return ret;
+
+	if (regval != ADXL355_DEVID_MST_VAL) {
+		dev_err(data->dev, "Invalid MEMS ID 0x%02x\n", regval);
+		return -ENODEV;
+	}
+
+	ret = regmap_read(data->regmap, ADXL355_PARTID, &regval);
+	if (ret < 0)
+		return ret;
+
+	if (regval != ADXL355_PARTID_VAL) {
+		dev_err(data->dev, "Invalid DEV ID 0x%02x\n", regval);
+		return -ENODEV;
+	}
+
+	/*
+	 * Perform a software reset to make sure the device is in a consistent
+	 * state after start up.
+	 */
+	ret = regmap_write(data->regmap, ADXL355_RESET, ADXL355_RESET_CODE);
+	if (ret < 0)
+		return ret;
+
+	adxl355_fill_3db_frequency_table(data);
+
+	return adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
+}
+
+static int adxl355_get_temp_data(struct adxl355_data *data,
+				 u8 addr, __be16 *out)
+{
+	return regmap_bulk_read(data->regmap, addr, out, sizeof(*out));
+}
+
+static int adxl355_read_axis(struct adxl355_data *data, u8 addr)
+{
+	__be32 regval;
+	int ret;
+
+	ret = regmap_bulk_read(data->regmap, addr, &regval, 3);
+	if (ret < 0)
+		return ret;
+
+	return be32_to_cpu(regval) >> 8;
+}
+
+static int adxl355_find_match(const int (*freq_tbl)[2], const int n,
+			      const int val, const int val2)
+{
+	int i;
+
+	for (i = 0; i < n; i++) {
+		if (freq_tbl[i][0] == val && freq_tbl[i][1] == val2)
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int adxl355_set_odr(struct adxl355_data *data,
+			   enum adxl355_odr odr)
+{
+	int ret = 0;
+
+	mutex_lock(&data->lock);
+
+	if (data->odr == odr)
+		goto out_unlock;
+
+	ret = adxl355_set_op_mode(data, ADXL355_STANDBY);
+	if (ret < 0)
+		goto out_unlock;
+
+	ret = regmap_update_bits(data->regmap, ADXL355_FILTER,
+				 ADXL355_FILTER_ODR_MSK,
+				 ADXL355_FILTER_ODR_MODE(odr));
+	if (!ret) {
+		data->odr = odr;
+		adxl355_fill_3db_frequency_table(data);
+	}
+
+out_unlock:
+	ret = adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static int adxl355_set_hpf_3db(struct adxl355_data *data,
+			       enum adxl355_hpf_3db hpf)
+{
+	int ret = 0;
+
+	mutex_lock(&data->lock);
+
+	if (data->hpf_3db == hpf)
+		goto out_unlock;
+
+	ret = adxl355_set_op_mode(data, ADXL355_STANDBY);
+	if (ret < 0)
+		goto out_unlock;
+
+	ret = regmap_update_bits(data->regmap, ADXL355_FILTER,
+				 ADXL355_FILTER_HPF_MSK,
+				 ADXL355_FILTER_HPF_MODE(hpf));
+	if (!ret)
+		data->hpf_3db = hpf;
+
+out_unlock:
+	ret = adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static int adxl355_set_calibbias(struct adxl355_data *data,
+				 int scan_index, int calibbias)
+{
+	int ret = 0;
+	__be16 reg = cpu_to_be16(calibbias);
+
+	mutex_lock(&data->lock);
+
+	ret = adxl355_set_op_mode(data, ADXL355_STANDBY);
+	if (ret < 0)
+		goto out_unlock;
+
+	switch (scan_index) {
+	case 0:
+		ret = regmap_bulk_write(data->regmap, ADXL355_OFFSET_X_H,
+					&reg, 2);
+		if (ret < 0)
+			goto out_unlock;
+		data->x_calibbias = calibbias;
+		break;
+	case 1:
+		ret = regmap_bulk_write(data->regmap, ADXL355_OFFSET_Y_H,
+					&reg, 2);
+		if (ret < 0)
+			goto out_unlock;
+		data->y_calibbias = calibbias;
+		break;
+	case 2:
+		ret = regmap_bulk_write(data->regmap, ADXL355_OFFSET_Z_H,
+					&reg, 2);
+		if (ret < 0)
+			goto out_unlock;
+		data->z_calibbias = calibbias;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+out_unlock:
+	ret = adxl355_set_op_mode(data, ADXL355_MEASUREMENT);
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static int adxl355_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct adxl355_data *data = iio_priv(indio_dev);
+	int ret;
+	__be16 out;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_TEMP:
+			ret = adxl355_get_temp_data(data, chan->address, &out);
+			if (ret < 0)
+				return ret;
+			*val = be16_to_cpu(out);
+
+			return IIO_VAL_INT;
+		case IIO_ACCEL:
+			ret = adxl355_read_axis(data, chan->address);
+			if (ret < 0)
+				return ret;
+			*val = sign_extend32(ret >> (chan->scan_type.shift),
+					     chan->scan_type.realbits - 1);
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_TEMP:
+			*val = TEMP_SCALE_VAL;
+			*val2 = TEMP_SCALE_VAL2;
+			return IIO_VAL_INT_PLUS_MICRO;
+		case IIO_ACCEL:
+			*val = 0;
+			*val2 = ADXL355_NSCALE;
+			return IIO_VAL_INT_PLUS_NANO;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_OFFSET:
+		*val = TEMP_OFFSET_VAL;
+		*val2 = TEMP_OFFSET_VAL2;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		if (chan->scan_index == 0)
+			*val = data->x_calibbias;
+		else if (chan->scan_index == 1)
+			*val = data->y_calibbias;
+		else
+			*val = data->z_calibbias;
+		*val = sign_extend32(*val, 15);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = adxl355_odr_table[data->odr][0];
+		*val2 = adxl355_odr_table[data->odr][1];
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
+		*val = data->adxl355_hpf_3db_table[data->hpf_3db][0];
+		*val2 = data->adxl355_hpf_3db_table[data->hpf_3db][1];
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+	return -EINVAL;
+}
+
+static int adxl355_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct adxl355_data *data = iio_priv(indio_dev);
+	int odr_idx, hpf_idx, calibbias;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		odr_idx = adxl355_find_match(adxl355_odr_table,
+					     ARRAY_SIZE(adxl355_odr_table),
+					     val, val2);
+		if (odr_idx < 0)
+			return odr_idx;
+
+		return adxl355_set_odr(data, odr_idx);
+	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
+		hpf_idx = adxl355_find_match(data->adxl355_hpf_3db_table,
+					ARRAY_SIZE(data->adxl355_hpf_3db_table),
+					     val, val2);
+		if (hpf_idx < 0)
+			return hpf_idx;
+
+		return adxl355_set_hpf_3db(data, hpf_idx);
+	case IIO_CHAN_INFO_CALIBBIAS:
+		calibbias = clamp_t(int, val, S16_MIN, S16_MAX);
+
+		return adxl355_set_calibbias(data, chan->scan_index, calibbias);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int adxl355_read_avail(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      const int **vals, int *type, int *length,
+			      long mask)
+{
+	struct adxl355_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*vals = (const int *)adxl355_odr_table;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		/* Values are stored in a 2D matrix */
+		*length = ARRAY_SIZE(adxl355_odr_table) * 2;
+
+		return IIO_AVAIL_LIST;
+	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
+		*vals = (const int *)(data->adxl355_hpf_3db_table);
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		/* Values are stored in a 2D matrix */
+		*length = ARRAY_SIZE(data->adxl355_hpf_3db_table) * 2;
+
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const unsigned long adxl355_avail_scan_masks[] = {
+	GENMASK(3, 0),
+	0
+};
+
+static const struct iio_info adxl355_info = {
+	.read_raw	= adxl355_read_raw,
+	.write_raw	= adxl355_write_raw,
+	.read_avail	= &adxl355_read_avail
+};
+
+#define ADXL355_ACCEL_CHANNEL(index, reg, axis) {			\
+	.type = IIO_ACCEL,						\
+	.address = reg,							\
+	.modified = 1,							\
+	.channel2 = IIO_MOD_##axis,					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
+			      BIT(IIO_CHAN_INFO_CALIBBIAS),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |		\
+				    BIT(IIO_CHAN_INFO_SAMP_FREQ) |	\
+		BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),	\
+	.info_mask_shared_by_type_available =				\
+		BIT(IIO_CHAN_INFO_SAMP_FREQ) |				\
+		BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),	\
+	.scan_index = index,						\
+	.scan_type = {							\
+		.sign = 's',						\
+		.realbits = 20,						\
+		.storagebits = 32,					\
+		.shift = 4,						\
+		.endianness = IIO_BE,					\
+	}								\
+}
+
+static const struct iio_chan_spec adxl355_channels[] = {
+	ADXL355_ACCEL_CHANNEL(0, ADXL355_XDATA3, X),
+	ADXL355_ACCEL_CHANNEL(1, ADXL355_YDATA3, Y),
+	ADXL355_ACCEL_CHANNEL(2, ADXL355_ZDATA3, Z),
+	{
+		.type = IIO_TEMP,
+		.address = ADXL355_TEMP2,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE) |
+				      BIT(IIO_CHAN_INFO_OFFSET),
+		.scan_index = 3,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 12,
+			.storagebits = 16,
+			.endianness = IIO_BE,
+		},
+	}
+};
+
+int adxl355_core_probe(struct device *dev, struct regmap *regmap,
+		       const char *name)
+{
+	struct adxl355_data *data;
+	struct iio_dev *indio_dev;
+	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;
+	data->op_mode = ADXL355_STANDBY;
+	mutex_init(&data->lock);
+
+	indio_dev->name = name;
+	indio_dev->info = &adxl355_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = adxl355_channels;
+	indio_dev->num_channels = ARRAY_SIZE(adxl355_channels);
+	indio_dev->available_scan_masks = adxl355_avail_scan_masks;
+
+	ret = adxl355_setup(data);
+	if (ret < 0) {
+		dev_err(dev, "ADXL355 setup failed\n");
+		return ret;
+	}
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+EXPORT_SYMBOL_GPL(adxl355_core_probe);
+
+MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
+MODULE_DESCRIPTION("ADXL355 3-Axis Digital Accelerometer core driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/accel/adxl355_i2c.c b/drivers/iio/accel/adxl355_i2c.c
new file mode 100644
index 000000000..6b84d8df2
--- /dev/null
+++ b/drivers/iio/accel/adxl355_i2c.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ADXL355 3-Axis Digital Accelerometer I2C driver
+ *
+ * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "adxl355.h"
+
+static const struct regmap_config adxl355_i2c_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x2F,
+	.rd_table = &adxl355_readable_regs_tbl,
+	.wr_table = &adxl355_writeable_regs_tbl
+};
+
+static int adxl355_i2c_probe(struct i2c_client *client)
+{
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_i2c(client, &adxl355_i2c_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "Error initializing i2c regmap: %ld\n",
+			PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	return adxl355_core_probe(&client->dev, regmap, client->name);
+}
+
+static const struct i2c_device_id adxl355_i2c_id[] = {
+	{ "adxl355", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, adxl355_i2c_id);
+
+static const struct of_device_id adxl355_of_match[] = {
+	{ .compatible = "adi,adxl355" },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, adxl355_of_match);
+
+static struct i2c_driver adxl355_i2c_driver = {
+	.driver = {
+		.name	= "adxl355_i2c",
+		.of_match_table = adxl355_of_match,
+	},
+	.probe_new	= adxl355_i2c_probe,
+	.id_table	= adxl355_i2c_id,
+};
+
+module_i2c_driver(adxl355_i2c_driver);
+
+MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
+MODULE_DESCRIPTION("ADXL355 3-Axis Digital Accelerometer I2C driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/accel/adxl355_spi.c b/drivers/iio/accel/adxl355_spi.c
new file mode 100644
index 000000000..108d1b308
--- /dev/null
+++ b/drivers/iio/accel/adxl355_spi.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ADXL355 3-Axis Digital Accelerometer SPI driver
+ *
+ * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "adxl355.h"
+
+static const struct regmap_config adxl355_spi_regmap_config = {
+	.reg_bits = 7,
+	.pad_bits = 1,
+	.val_bits = 8,
+	.read_flag_mask = BIT(0),
+	.max_register = 0x2F,
+	.rd_table = &adxl355_readable_regs_tbl,
+	.wr_table = &adxl355_writeable_regs_tbl
+};
+
+static int adxl355_spi_probe(struct spi_device *spi)
+{
+	const struct spi_device_id *id = spi_get_device_id(spi);
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_spi(spi, &adxl355_spi_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&spi->dev, "Error initializing spi regmap: %ld\n",
+			PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	return adxl355_core_probe(&spi->dev, regmap, id->name);
+}
+
+static const struct spi_device_id adxl355_spi_id[] = {
+	{ "adxl355", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(spi, adxl355_spi_id);
+
+static const struct of_device_id adxl355_of_match[] = {
+	{ .compatible = "adi,adxl355" },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, adxl355_of_match);
+
+static struct spi_driver adxl355_spi_driver = {
+	.driver = {
+		.name	= "adxl355_spi",
+		.of_match_table = adxl355_of_match,
+	},
+	.probe		= adxl355_spi_probe,
+	.id_table	= adxl355_spi_id,
+};
+
+module_spi_driver(adxl355_spi_driver);
+
+MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
+MODULE_DESCRIPTION("ADXL355 3-Axis Digital Accelerometer SPI driver");
+MODULE_LICENSE("GPL v2");
-- 
2.30.1