linux/drivers/iio/accel/adxl313_core.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * ADXL313 3-Axis Digital Accelerometer
 *
 * Copyright (c) 2021 Lucas Stankus <lucas.p.stankus@gmail.com>
 *
 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL313.pdf
 */

#include <linux/bitfield.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/regmap.h>

#include "adxl313.h"

static const struct regmap_range adxl313_readable_reg_range[] = {
	regmap_reg_range(ADXL313_REG_DEVID0, ADXL313_REG_XID),
	regmap_reg_range(ADXL313_REG_SOFT_RESET, ADXL313_REG_SOFT_RESET),
	regmap_reg_range(ADXL313_REG_OFS_AXIS(0), ADXL313_REG_OFS_AXIS(2)),
	regmap_reg_range(ADXL313_REG_THRESH_ACT, ADXL313_REG_ACT_INACT_CTL),
	regmap_reg_range(ADXL313_REG_BW_RATE, ADXL313_REG_FIFO_STATUS),
};

const struct regmap_access_table adxl313_readable_regs_table = {
	.yes_ranges = adxl313_readable_reg_range,
	.n_yes_ranges = ARRAY_SIZE(adxl313_readable_reg_range),
};
EXPORT_SYMBOL_NS_GPL(adxl313_readable_regs_table, IIO_ADXL313);

static const struct regmap_range adxl313_writable_reg_range[] = {
	regmap_reg_range(ADXL313_REG_SOFT_RESET, ADXL313_REG_SOFT_RESET),
	regmap_reg_range(ADXL313_REG_OFS_AXIS(0), ADXL313_REG_OFS_AXIS(2)),
	regmap_reg_range(ADXL313_REG_THRESH_ACT, ADXL313_REG_ACT_INACT_CTL),
	regmap_reg_range(ADXL313_REG_BW_RATE, ADXL313_REG_INT_MAP),
	regmap_reg_range(ADXL313_REG_DATA_FORMAT, ADXL313_REG_DATA_FORMAT),
	regmap_reg_range(ADXL313_REG_FIFO_CTL, ADXL313_REG_FIFO_CTL),
};

const struct regmap_access_table adxl313_writable_regs_table = {
	.yes_ranges = adxl313_writable_reg_range,
	.n_yes_ranges = ARRAY_SIZE(adxl313_writable_reg_range),
};
EXPORT_SYMBOL_NS_GPL(adxl313_writable_regs_table, IIO_ADXL313);

struct adxl313_data {
	struct regmap	*regmap;
	struct mutex	lock; /* lock to protect transf_buf */
	__le16		transf_buf ____cacheline_aligned;
};

static const int adxl313_odr_freqs[][2] = {
	[0] = { 6, 250000 },
	[1] = { 12, 500000 },
	[2] = { 25, 0 },
	[3] = { 50, 0 },
	[4] = { 100, 0 },
	[5] = { 200, 0 },
	[6] = { 400, 0 },
	[7] = { 800, 0 },
	[8] = { 1600, 0 },
	[9] = { 3200, 0 },
};

#define ADXL313_ACCEL_CHANNEL(index, axis) {				\
	.type = IIO_ACCEL,						\
	.address = index,						\
	.modified = 1,							\
	.channel2 = IIO_MOD_##axis,					\
	.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),	\
	.info_mask_shared_by_type_available =				\
		BIT(IIO_CHAN_INFO_SAMP_FREQ),				\
	.scan_type = {							\
		.realbits = 13,						\
	},								\
}

static const struct iio_chan_spec adxl313_channels[] = {
	ADXL313_ACCEL_CHANNEL(0, X),
	ADXL313_ACCEL_CHANNEL(1, Y),
	ADXL313_ACCEL_CHANNEL(2, Z),
};

static int adxl313_set_odr(struct adxl313_data *data,
			   unsigned int freq1, unsigned int freq2)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(adxl313_odr_freqs); i++) {
		if (adxl313_odr_freqs[i][0] == freq1 &&
		    adxl313_odr_freqs[i][1] == freq2)
			break;
	}

	if (i == ARRAY_SIZE(adxl313_odr_freqs))
		return -EINVAL;

	return regmap_update_bits(data->regmap, ADXL313_REG_BW_RATE,
				  ADXL313_RATE_MSK,
				  FIELD_PREP(ADXL313_RATE_MSK, ADXL313_RATE_BASE + i));
}

static int adxl313_read_axis(struct adxl313_data *data,
			     struct iio_chan_spec const *chan)
{
	int ret;

	mutex_lock(&data->lock);

	ret = regmap_bulk_read(data->regmap,
			       ADXL313_REG_DATA_AXIS(chan->address),
			       &data->transf_buf, sizeof(data->transf_buf));
	if (ret)
		goto unlock_ret;

	ret = le16_to_cpu(data->transf_buf);

unlock_ret:
	mutex_unlock(&data->lock);
	return ret;
}

static int adxl313_read_freq_avail(struct iio_dev *indio_dev,
				   struct iio_chan_spec const *chan,
				   const int **vals, int *type, int *length,
				   long mask)
{
	switch (mask) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		*vals = (const int *)adxl313_odr_freqs;
		*length = ARRAY_SIZE(adxl313_odr_freqs) * 2;
		*type = IIO_VAL_INT_PLUS_MICRO;
		return IIO_AVAIL_LIST;
	default:
		return -EINVAL;
	}
}

static int adxl313_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val, int *val2, long mask)
{
	struct adxl313_data *data = iio_priv(indio_dev);
	unsigned int regval;
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = adxl313_read_axis(data, chan);
		if (ret < 0)
			return ret;

		*val = sign_extend32(ret, chan->scan_type.realbits - 1);
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		/*
		 * Scale for any g range is given in datasheet as
		 * 1024 LSB/g = 0.0009765625 * 9.80665 = 0.009576806640625 m/s^2
		 */
		*val = 0;
		*val2 = 9576806;
		return IIO_VAL_INT_PLUS_NANO;
	case IIO_CHAN_INFO_CALIBBIAS:
		ret = regmap_read(data->regmap,
				  ADXL313_REG_OFS_AXIS(chan->address), &regval);
		if (ret)
			return ret;

		/*
		 * 8-bit resolution at +/- 0.5g, that is 4x accel data scale
		 * factor at full resolution
		 */
		*val = sign_extend32(regval, 7) * 4;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SAMP_FREQ:
		ret = regmap_read(data->regmap, ADXL313_REG_BW_RATE, &regval);
		if (ret)
			return ret;

		ret = FIELD_GET(ADXL313_RATE_MSK, regval) - ADXL313_RATE_BASE;
		*val = adxl313_odr_freqs[ret][0];
		*val2 = adxl313_odr_freqs[ret][1];
		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

static int adxl313_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int val, int val2, long mask)
{
	struct adxl313_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_CALIBBIAS:
		/*
		 * 8-bit resolution at +/- 0.5g, that is 4x accel data scale
		 * factor at full resolution
		 */
		if (clamp_val(val, -128 * 4, 127 * 4) != val)
			return -EINVAL;

		return regmap_write(data->regmap,
				    ADXL313_REG_OFS_AXIS(chan->address),
				    val / 4);
	case IIO_CHAN_INFO_SAMP_FREQ:
		return adxl313_set_odr(data, val, val2);
	default:
		return -EINVAL;
	}
}

static const struct iio_info adxl313_info = {
	.read_raw	= adxl313_read_raw,
	.write_raw	= adxl313_write_raw,
	.read_avail	= adxl313_read_freq_avail,
};

static int adxl313_setup(struct device *dev, struct adxl313_data *data,
			 int (*setup)(struct device *, struct regmap *))
{
	unsigned int regval;
	int ret;

	/* Ensures the device is in a consistent state after start up */
	ret = regmap_write(data->regmap, ADXL313_REG_SOFT_RESET,
			   ADXL313_SOFT_RESET);
	if (ret)
		return ret;

	if (setup) {
		ret = setup(dev, data->regmap);
		if (ret)
			return ret;
	}

	ret = regmap_read(data->regmap, ADXL313_REG_DEVID0, &regval);
	if (ret)
		return ret;

	if (regval != ADXL313_DEVID0) {
		dev_err(dev, "Invalid manufacturer ID: 0x%02x\n", regval);
		return -ENODEV;
	}

	ret = regmap_read(data->regmap, ADXL313_REG_DEVID1, &regval);
	if (ret)
		return ret;

	if (regval != ADXL313_DEVID1) {
		dev_err(dev, "Invalid mems ID: 0x%02x\n", regval);
		return -ENODEV;
	}

	ret = regmap_read(data->regmap, ADXL313_REG_PARTID, &regval);
	if (ret)
		return ret;

	if (regval != ADXL313_PARTID) {
		dev_err(dev, "Invalid device ID: 0x%02x\n", regval);
		return -ENODEV;
	}

	/* Sets the range to +/- 4g */
	ret = regmap_update_bits(data->regmap, ADXL313_REG_DATA_FORMAT,
				 ADXL313_RANGE_MSK,
				 FIELD_PREP(ADXL313_RANGE_MSK, ADXL313_RANGE_4G));
	if (ret)
		return ret;

	/* Enables full resolution */
	ret = regmap_update_bits(data->regmap, ADXL313_REG_DATA_FORMAT,
				 ADXL313_FULL_RES, ADXL313_FULL_RES);
	if (ret)
		return ret;

	/* Enables measurement mode */
	return regmap_update_bits(data->regmap, ADXL313_REG_POWER_CTL,
				  ADXL313_POWER_CTL_MSK,
				  ADXL313_MEASUREMENT_MODE);
}

/**
 * adxl313_core_probe() - probe and setup for adxl313 accelerometer
 * @dev:	Driver model representation of the device
 * @regmap:	Register map of the device
 * @name:	Device name buffer reference
 * @setup:	Setup routine to be executed right before the standard device
 *		setup, can also be set to NULL if not required
 *
 * Return: 0 on success, negative errno on error cases
 */
int adxl313_core_probe(struct device *dev,
		       struct regmap *regmap,
		       const char *name,
		       int (*setup)(struct device *, struct regmap *))
{
	struct adxl313_data *data;
	struct iio_dev *indio_dev;
	int ret;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
	if (!indio_dev)
		return -ENOMEM;

	data = iio_priv(indio_dev);
	data->regmap = regmap;
	mutex_init(&data->lock);

	indio_dev->name = name;
	indio_dev->info = &adxl313_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = adxl313_channels;
	indio_dev->num_channels = ARRAY_SIZE(adxl313_channels);

	ret = adxl313_setup(dev, data, setup);
	if (ret) {
		dev_err(dev, "ADXL313 setup failed\n");
		return ret;
	}

	return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL_NS_GPL(adxl313_core_probe, IIO_ADXL313);

MODULE_AUTHOR("Lucas Stankus <lucas.p.stankus@gmail.com>");
MODULE_DESCRIPTION("ADXL313 3-Axis Digital Accelerometer core driver");
MODULE_LICENSE("GPL v2");