drivers/iio/accel/adxl345_core.c - linux - Git at Google

 // 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/regmap.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 NHZ_PER_HZ			1000000000LL

 #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), &regval);
 		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, &regval);
 		if (ret < 0)
 			return ret;

 		samp_freq_nhz = ADXL345_BASE_RATE_NANO_HZ <<
 				(regval & ADXL345_BW_RATE);
 		*val = div_s64_rem(samp_freq_nhz, NHZ_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 * NHZ_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 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, const char *name)
 {
 	struct adxl345_data *data;
 	struct iio_dev *indio_dev;
 	u32 regval;
 	int ret;

 	ret = regmap_read(regmap, ADXL345_REG_DEVID, &regval);
 	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);
 	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) {
 		dev_err(dev, "Failed to set data range: %d\n", ret);
 		return ret;
 	}

 	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 = 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_GPL(adxl345_core_probe);

 MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
 MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
 MODULE_LICENSE("GPL v2");
	// 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/regmap.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 NHZ_PER_HZ 1000000000LL

	#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), &regval);
	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, &regval);
	if (ret < 0)
	return ret;

	samp_freq_nhz = ADXL345_BASE_RATE_NANO_HZ <<
	(regval & ADXL345_BW_RATE);
	*val = div_s64_rem(samp_freq_nhz, NHZ_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 * NHZ_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 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, const char *name)
	{
	struct adxl345_data *data;
	struct iio_dev *indio_dev;
	u32 regval;
	int ret;

	ret = regmap_read(regmap, ADXL345_REG_DEVID, &regval);
	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);
	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) {
	dev_err(dev, "Failed to set data range: %d\n", ret);
	return ret;
	}

	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 = 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_GPL(adxl345_core_probe);

	MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
	MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
	MODULE_LICENSE("GPL v2");