// SPDX-License-Identifier: GPL-2.0-only
/*
* ADXL345 3-Axis Digital Accelerometer IIO core driver
*
* Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com>
*
* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf
*/
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/units.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include "adxl345.h"
#define ADXL345_REG_DEVID 0x00
#define ADXL345_REG_OFSX 0x1e
#define ADXL345_REG_OFSY 0x1f
#define ADXL345_REG_OFSZ 0x20
#define ADXL345_REG_OFS_AXIS(index) (ADXL345_REG_OFSX + (index))
#define ADXL345_REG_BW_RATE 0x2C
#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_BW_RATE GENMASK(3, 0)
#define ADXL345_BASE_RATE_NANO_HZ 97656250LL
#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;
/*
* The Datasheet lists a resolution of Resolution is ~49 mg per LSB. That's
* ~480mm/s**2 per LSB.
*/
static const int adxl375_uscale = 480000;
struct adxl345_data {
struct regmap *regmap;
u8 data_range;
enum adxl345_device_type type;
};
#define ADXL345_CHANNEL(index, axis) { \
.type = IIO_ACCEL, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.address = index, \
.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), \
}
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;
long long samp_freq_nhz;
unsigned int regval;
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;
switch (data->type) {
case ADXL345:
*val2 = adxl345_uscale;
break;
case ADXL375:
*val2 = adxl375_uscale;
break;
}
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_CALIBBIAS:
ret = regmap_read(data->regmap,
ADXL345_REG_OFS_AXIS(chan->address), ®val);
if (ret < 0)
return ret;
/*
* 8-bit resolution at +/- 2g, that is 4x accel data scale
* factor
*/
*val = sign_extend32(regval, 7) * 4;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SAMP_FREQ:
ret = regmap_read(data->regmap, ADXL345_REG_BW_RATE, ®val);
if (ret < 0)
return ret;
samp_freq_nhz = ADXL345_BASE_RATE_NANO_HZ <<
(regval & ADXL345_BW_RATE);
*val = div_s64_rem(samp_freq_nhz, NANOHZ_PER_HZ, val2);
return IIO_VAL_INT_PLUS_NANO;
}
return -EINVAL;
}
static int adxl345_write_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);
s64 n;
switch (mask) {
case IIO_CHAN_INFO_CALIBBIAS:
/*
* 8-bit resolution at +/- 2g, that is 4x accel data scale
* factor
*/
return regmap_write(data->regmap,
ADXL345_REG_OFS_AXIS(chan->address),
val / 4);
case IIO_CHAN_INFO_SAMP_FREQ:
n = div_s64(val * NANOHZ_PER_HZ + val2,
ADXL345_BASE_RATE_NANO_HZ);
return regmap_update_bits(data->regmap, ADXL345_REG_BW_RATE,
ADXL345_BW_RATE,
clamp_val(ilog2(n), 0,
ADXL345_BW_RATE));
}
return -EINVAL;
}
static int adxl345_write_raw_get_fmt(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
long mask)
{
switch (mask) {
case IIO_CHAN_INFO_CALIBBIAS:
return IIO_VAL_INT;
case IIO_CHAN_INFO_SAMP_FREQ:
return IIO_VAL_INT_PLUS_NANO;
default:
return -EINVAL;
}
}
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
"0.09765625 0.1953125 0.390625 0.78125 1.5625 3.125 6.25 12.5 25 50 100 200 400 800 1600 3200"
);
static struct attribute *adxl345_attrs[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL
};
static const struct attribute_group adxl345_attrs_group = {
.attrs = adxl345_attrs,
};
static const struct iio_info adxl345_info = {
.attrs = &adxl345_attrs_group,
.read_raw = adxl345_read_raw,
.write_raw = adxl345_write_raw,
.write_raw_get_fmt = adxl345_write_raw_get_fmt,
};
static int adxl345_powerup(void *regmap)
{
return regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_MEASURE);
}
static void adxl345_powerdown(void *regmap)
{
regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_STANDBY);
}
int adxl345_core_probe(struct device *dev, struct regmap *regmap)
{
enum adxl345_device_type type;
struct adxl345_data *data;
struct iio_dev *indio_dev;
const char *name;
u32 regval;
int ret;
type = (uintptr_t)device_get_match_data(dev);
switch (type) {
case ADXL345:
name = "adxl345";
break;
case ADXL375:
name = "adxl375";
break;
default:
return -EINVAL;
}
ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val);
if (ret < 0)
return dev_err_probe(dev, ret, "Error reading device ID\n");
if (regval != ADXL345_DEVID)
return dev_err_probe(dev, -ENODEV, "Invalid device ID: %x, expected %x\n",
regval, ADXL345_DEVID);
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
data->regmap = regmap;
data->type = type;
/* 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)
return dev_err_probe(dev, ret, "Failed to set data range\n");
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 = adxl345_powerup(data->regmap);
if (ret < 0)
return dev_err_probe(dev, ret, "Failed to enable measurement mode\n");
ret = devm_add_action_or_reset(dev, adxl345_powerdown, data->regmap);
if (ret < 0)
return ret;
return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL_NS_GPL(adxl345_core_probe, IIO_ADXL345);
MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
MODULE_LICENSE("GPL v2");