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Commit c6236075 authored by Eva Rachel Retuya's avatar Eva Rachel Retuya Committed by Jonathan Cameron
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iio: accel: Add driver for the Analog Devices ADXL345 3-axis accelerometer 

Add basic IIO support for the Analog Devices ADXL345 3-axis accelerometer.
The datasheet can be found here:
http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf



Signed-off-by: default avatarEva Rachel Retuya <eraretuya@gmail.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Alison Schofield <amsfield22@gmail.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 48458b0c

drivers/iio/accel/Kconfig

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menu "Accelerometers"



config ADXL345

	tristate "Analog Devices ADXL345 3-Axis Digital Accelerometer Driver"

	depends on !(INPUT_ADXL34X=y || INPUT_ADXL34X=m)

	depends on I2C

	help

	  Say Y here if you want to build support for the Analog Devices

	  ADXL345 3-axis digital accelerometer.



	  To compile this driver as a module, choose M here: the

	  module will be called adxl345.



config BMA180

	tristate "Bosch BMA180/BMA250 3-Axis Accelerometer Driver"

	depends on I2C

drivers/iio/accel/Makefile

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#



# When adding new entries keep the list in alphabetical order

obj-$(CONFIG_ADXL345) += adxl345.o

obj-$(CONFIG_BMA180) += bma180.o

obj-$(CONFIG_BMA220) += bma220_spi.o

obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o

drivers/iio/accel/adxl345.c

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/*

 * ADXL345 3-Axis Digital Accelerometer

 *

 * Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com>

 *

 * This file is subject to the terms and conditions of version 2 of

 * the GNU General Public License. See the file COPYING in the main

 * directory of this archive for more details.

 *

 * IIO driver for ADXL345

 * 7-bit I2C slave address: 0x1D (ALT ADDRESS pin tied to VDDIO) or

 * 0x53 (ALT ADDRESS pin grounded)

 */



#include <linux/i2c.h>

#include <linux/module.h>



#include <linux/iio/iio.h>



#define ADXL345_REG_DEVID		0x00

#define ADXL345_REG_POWER_CTL		0x2D

#define ADXL345_REG_DATA_FORMAT		0x31

#define ADXL345_REG_DATAX0		0x32

#define ADXL345_REG_DATAY0		0x34

#define ADXL345_REG_DATAZ0		0x36



#define ADXL345_POWER_CTL_MEASURE	BIT(3)

#define ADXL345_POWER_CTL_STANDBY	0x00



#define ADXL345_DATA_FORMAT_FULL_RES	BIT(3) /* Up to 13-bits resolution */

#define ADXL345_DATA_FORMAT_2G		0

#define ADXL345_DATA_FORMAT_4G		1

#define ADXL345_DATA_FORMAT_8G		2

#define ADXL345_DATA_FORMAT_16G		3



#define ADXL345_DEVID			0xE5



/*

 * In full-resolution mode, scale factor is maintained at ~4 mg/LSB

 * in all g ranges.

 *

 * At +/- 16g with 13-bit resolution, scale is computed as:

 * (16 + 16) * 9.81 / (2^13 - 1) = 0.0383

 */

static const int adxl345_uscale = 38300;



struct adxl345_data {

	struct i2c_client *client;

	u8 data_range;

};



#define ADXL345_CHANNEL(reg, axis) {					\

	.type = IIO_ACCEL,						\

	.modified = 1,							\

	.channel2 = IIO_MOD_##axis,					\

	.address = reg,							\

	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\

	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),		\

}



static const struct iio_chan_spec adxl345_channels[] = {

	ADXL345_CHANNEL(ADXL345_REG_DATAX0, X),

	ADXL345_CHANNEL(ADXL345_REG_DATAY0, Y),

	ADXL345_CHANNEL(ADXL345_REG_DATAZ0, Z),

};



static int adxl345_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *chan,

			    int *val, int *val2, long mask)

{

	struct adxl345_data *data = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		/*

		 * Data is stored in adjacent registers:

		 * ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte

		 * and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte

		 */

		ret = i2c_smbus_read_word_data(data->client, chan->address);

		if (ret < 0)

			return ret;



		*val = sign_extend32(ret, 12);

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		*val = 0;

		*val2 = adxl345_uscale;



		return IIO_VAL_INT_PLUS_MICRO;

	}



	return -EINVAL;

}



static const struct iio_info adxl345_info = {

	.driver_module	= THIS_MODULE,

	.read_raw	= adxl345_read_raw,

};



static int adxl345_probe(struct i2c_client *client,

			 const struct i2c_device_id *id)

{

	struct adxl345_data *data;

	struct iio_dev *indio_dev;

	int ret;



	ret = i2c_smbus_read_byte_data(client, ADXL345_REG_DEVID);

	if (ret < 0) {

		dev_err(&client->dev, "Error reading device ID: %d\n", ret);

		return ret;

	}



	if (ret != ADXL345_DEVID) {

		dev_err(&client->dev, "Invalid device ID: %d\n", ret);

		return -ENODEV;

	}



	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));

	if (!indio_dev)

		return -ENOMEM;



	data = iio_priv(indio_dev);

	i2c_set_clientdata(client, indio_dev);

	data->client = client;

	/* Enable full-resolution mode */

	data->data_range = ADXL345_DATA_FORMAT_FULL_RES;



	ret = i2c_smbus_write_byte_data(data->client, ADXL345_REG_DATA_FORMAT,

					data->data_range);

	if (ret < 0) {

		dev_err(&client->dev, "Failed to set data range: %d\n", ret);

		return ret;

	}



	indio_dev->dev.parent = &client->dev;

	indio_dev->name = id->name;

	indio_dev->info = &adxl345_info;

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = adxl345_channels;

	indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);



	/* Enable measurement mode */

	ret = i2c_smbus_write_byte_data(data->client, ADXL345_REG_POWER_CTL,

					ADXL345_POWER_CTL_MEASURE);

	if (ret < 0) {

		dev_err(&client->dev, "Failed to enable measurement mode: %d\n",

			ret);

		return ret;

	}



	ret = iio_device_register(indio_dev);

	if (ret < 0) {

		dev_err(&client->dev, "iio_device_register failed: %d\n", ret);

		i2c_smbus_write_byte_data(data->client, ADXL345_REG_POWER_CTL,

					  ADXL345_POWER_CTL_STANDBY);

	}



	return ret;

}



static int adxl345_remove(struct i2c_client *client)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	struct adxl345_data *data = iio_priv(indio_dev);



	iio_device_unregister(indio_dev);



	return i2c_smbus_write_byte_data(data->client, ADXL345_REG_POWER_CTL,

					 ADXL345_POWER_CTL_STANDBY);

}



static const struct i2c_device_id adxl345_i2c_id[] = {

	{ "adxl345", 0 },

	{ }

};



MODULE_DEVICE_TABLE(i2c, adxl345_i2c_id);



static struct i2c_driver adxl345_driver = {

	.driver = {

		.name	= "adxl345",

	},

	.probe		= adxl345_probe,

	.remove		= adxl345_remove,

	.id_table	= adxl345_i2c_id,

};



module_i2c_driver(adxl345_driver);



MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");

MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer driver");

MODULE_LICENSE("GPL v2");