diff options
Diffstat (limited to 'drivers/iio/accel/adxl345_core.c')
| -rw-r--r-- | drivers/iio/accel/adxl345_core.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c new file mode 100644 index 000000000..1919e0089 --- /dev/null +++ b/drivers/iio/accel/adxl345_core.c @@ -0,0 +1,288 @@ +// 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"); |