iio: accel: Add driver support for ADXL355

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

@@ -593,6 +593,13 @@ 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

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

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

drivers/iio/accel/adxl355.h

@@ -0,0 +1,83 @@
+/* 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_range adxl355_read_reg_range[];
+
+extern const struct regmap_access_table adxl355_readable_regs_tbl;
+
+extern const struct regmap_range adxl355_write_reg_range[];
+
+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_ */