// SPDX-License-Identifier: GPL-2.0-only /* * ADXL345 3-Axis Digital Accelerometer IIO core driver * * Copyright (c) 2017 Eva Rachel Retuya * * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf */ #include #include #include #include #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), ®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, 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, ®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); 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_NS_GPL(adxl345_core_probe, IIO_ADXL345); MODULE_AUTHOR("Eva Rachel Retuya "); MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver"); MODULE_LICENSE("GPL v2");