![Eva Rachel Retuya](/assets/img/avatar_default.png)
Move I2C-specific code into its own file and rely on regmap to access registers. The core code provides access to x, y, z and scale readings. Signed-off-by: Eva Rachel Retuya <eraretuya@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
180 lines
4.5 KiB
C
180 lines
4.5 KiB
C
/*
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* ADXL345 3-Axis Digital Accelerometer IIO core driver
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*
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* Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com>
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*
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* This file is subject to the terms and conditions of version 2 of
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* the GNU General Public License. See the file COPYING in the main
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* directory of this archive for more details.
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*/
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#include <linux/module.h>
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#include <linux/regmap.h>
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#include <linux/iio/iio.h>
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#include "adxl345.h"
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#define ADXL345_REG_DEVID 0x00
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#define ADXL345_REG_POWER_CTL 0x2D
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#define ADXL345_REG_DATA_FORMAT 0x31
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#define ADXL345_REG_DATAX0 0x32
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#define ADXL345_REG_DATAY0 0x34
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#define ADXL345_REG_DATAZ0 0x36
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#define ADXL345_POWER_CTL_MEASURE BIT(3)
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#define ADXL345_POWER_CTL_STANDBY 0x00
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#define ADXL345_DATA_FORMAT_FULL_RES BIT(3) /* Up to 13-bits resolution */
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#define ADXL345_DATA_FORMAT_2G 0
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#define ADXL345_DATA_FORMAT_4G 1
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#define ADXL345_DATA_FORMAT_8G 2
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#define ADXL345_DATA_FORMAT_16G 3
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#define ADXL345_DEVID 0xE5
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/*
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* In full-resolution mode, scale factor is maintained at ~4 mg/LSB
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* in all g ranges.
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*
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* At +/- 16g with 13-bit resolution, scale is computed as:
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* (16 + 16) * 9.81 / (2^13 - 1) = 0.0383
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*/
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static const int adxl345_uscale = 38300;
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struct adxl345_data {
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struct regmap *regmap;
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u8 data_range;
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};
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#define ADXL345_CHANNEL(reg, axis) { \
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.type = IIO_ACCEL, \
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.modified = 1, \
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.channel2 = IIO_MOD_##axis, \
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.address = reg, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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}
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static const struct iio_chan_spec adxl345_channels[] = {
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ADXL345_CHANNEL(ADXL345_REG_DATAX0, X),
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ADXL345_CHANNEL(ADXL345_REG_DATAY0, Y),
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ADXL345_CHANNEL(ADXL345_REG_DATAZ0, Z),
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};
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static int adxl345_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct adxl345_data *data = iio_priv(indio_dev);
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__le16 regval;
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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/*
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* Data is stored in adjacent registers:
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* ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte
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* and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte
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*/
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ret = regmap_bulk_read(data->regmap, chan->address, ®val,
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sizeof(regval));
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if (ret < 0)
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return ret;
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*val = sign_extend32(le16_to_cpu(regval), 12);
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = 0;
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*val2 = adxl345_uscale;
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return IIO_VAL_INT_PLUS_MICRO;
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}
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return -EINVAL;
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}
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static const struct iio_info adxl345_info = {
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.driver_module = THIS_MODULE,
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.read_raw = adxl345_read_raw,
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};
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int adxl345_core_probe(struct device *dev, struct regmap *regmap,
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const char *name)
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{
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struct adxl345_data *data;
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struct iio_dev *indio_dev;
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u32 regval;
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int ret;
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ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val);
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if (ret < 0) {
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dev_err(dev, "Error reading device ID: %d\n", ret);
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return ret;
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}
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if (regval != ADXL345_DEVID) {
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dev_err(dev, "Invalid device ID: %x, expected %x\n",
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regval, ADXL345_DEVID);
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return -ENODEV;
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}
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indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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data = iio_priv(indio_dev);
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dev_set_drvdata(dev, indio_dev);
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data->regmap = regmap;
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/* Enable full-resolution mode */
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data->data_range = ADXL345_DATA_FORMAT_FULL_RES;
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ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
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data->data_range);
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if (ret < 0) {
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dev_err(dev, "Failed to set data range: %d\n", ret);
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return ret;
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}
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indio_dev->dev.parent = dev;
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indio_dev->name = name;
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indio_dev->info = &adxl345_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = adxl345_channels;
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indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
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/* Enable measurement mode */
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ret = regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
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ADXL345_POWER_CTL_MEASURE);
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if (ret < 0) {
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dev_err(dev, "Failed to enable measurement mode: %d\n", ret);
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return ret;
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}
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ret = iio_device_register(indio_dev);
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if (ret < 0) {
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dev_err(dev, "iio_device_register failed: %d\n", ret);
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regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
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ADXL345_POWER_CTL_STANDBY);
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(adxl345_core_probe);
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int adxl345_core_remove(struct device *dev)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct adxl345_data *data = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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return regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
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ADXL345_POWER_CTL_STANDBY);
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}
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EXPORT_SYMBOL_GPL(adxl345_core_remove);
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MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
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MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
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MODULE_LICENSE("GPL v2");
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