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/*
* ADXL345 3-Axis Digital Accelerometer IIO core driver
*
* 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.
*
* Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf
*/
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include "adxl345.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_REG_DATA_AXIS(index) \
(ADXL345_REG_DATAX0 + (index) * sizeof(__le16))
#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 regmap *regmap;
u8 data_range;
};
#define ADXL345_CHANNEL(index, axis) { \
.type = IIO_ACCEL, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.address = index, \
.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(0, X),
ADXL345_CHANNEL(1, Y),
ADXL345_CHANNEL(2, 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);
__le16 accel;
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 = regmap_bulk_read(data->regmap,
ADXL345_REG_DATA_AXIS(chan->address),
&accel, sizeof(accel));
if (ret < 0)
return ret;
*val = sign_extend32(le16_to_cpu(accel), 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 = {
.read_raw = adxl345_read_raw,
};
int adxl345_core_probe(struct device *dev, struct regmap *regmap,
const char *name)
{
struct adxl345_data *data;
struct iio_dev *indio_dev;
u32 regval;
int ret;
ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val);
if (ret < 0) {
dev_err(dev, "Error reading device ID: %d\n", ret);
return ret;
}
if (regval != ADXL345_DEVID) {
dev_err(dev, "Invalid device ID: %x, expected %x\n",
regval, ADXL345_DEVID);
return -ENODEV;
}
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
dev_set_drvdata(dev, indio_dev);
data->regmap = regmap;
/* Enable full-resolution mode */
data->data_range = ADXL345_DATA_FORMAT_FULL_RES;
ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
data->data_range);
if (ret < 0) {
dev_err(dev, "Failed to set data range: %d\n", ret);
return ret;
}
indio_dev->dev.parent = dev;
indio_dev->name = 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 = regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
ADXL345_POWER_CTL_MEASURE);
if (ret < 0) {
dev_err(dev, "Failed to enable measurement mode: %d\n", ret);
return ret;
}
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(dev, "iio_device_register failed: %d\n", ret);
regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
ADXL345_POWER_CTL_STANDBY);
}
return ret;
}
EXPORT_SYMBOL_GPL(adxl345_core_probe);
int adxl345_core_remove(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct adxl345_data *data = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
return regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
ADXL345_POWER_CTL_STANDBY);
}
EXPORT_SYMBOL_GPL(adxl345_core_remove);
MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
MODULE_LICENSE("GPL v2");
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