2 * ADXL345 3-Axis Digital Accelerometer IIO core driver
4 * Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com>
6 * This file is subject to the terms and conditions of version 2 of
7 * the GNU General Public License. See the file COPYING in the main
8 * directory of this archive for more details.
10 * Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf
13 #include <linux/module.h>
14 #include <linux/regmap.h>
16 #include <linux/iio/iio.h>
20 #define ADXL345_REG_DEVID 0x00
21 #define ADXL345_REG_POWER_CTL 0x2D
22 #define ADXL345_REG_DATA_FORMAT 0x31
23 #define ADXL345_REG_DATAX0 0x32
24 #define ADXL345_REG_DATAY0 0x34
25 #define ADXL345_REG_DATAZ0 0x36
26 #define ADXL345_REG_DATA_AXIS(index) \
27 (ADXL345_REG_DATAX0 + (index) * sizeof(__le16))
29 #define ADXL345_POWER_CTL_MEASURE BIT(3)
30 #define ADXL345_POWER_CTL_STANDBY 0x00
32 #define ADXL345_DATA_FORMAT_FULL_RES BIT(3) /* Up to 13-bits resolution */
33 #define ADXL345_DATA_FORMAT_2G 0
34 #define ADXL345_DATA_FORMAT_4G 1
35 #define ADXL345_DATA_FORMAT_8G 2
36 #define ADXL345_DATA_FORMAT_16G 3
38 #define ADXL345_DEVID 0xE5
41 * In full-resolution mode, scale factor is maintained at ~4 mg/LSB
44 * At +/- 16g with 13-bit resolution, scale is computed as:
45 * (16 + 16) * 9.81 / (2^13 - 1) = 0.0383
47 static const int adxl345_uscale = 38300;
50 struct regmap *regmap;
54 #define ADXL345_CHANNEL(index, axis) { \
57 .channel2 = IIO_MOD_##axis, \
59 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
60 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
63 static const struct iio_chan_spec adxl345_channels[] = {
64 ADXL345_CHANNEL(0, X),
65 ADXL345_CHANNEL(1, Y),
66 ADXL345_CHANNEL(2, Z),
69 static int adxl345_read_raw(struct iio_dev *indio_dev,
70 struct iio_chan_spec const *chan,
71 int *val, int *val2, long mask)
73 struct adxl345_data *data = iio_priv(indio_dev);
78 case IIO_CHAN_INFO_RAW:
80 * Data is stored in adjacent registers:
81 * ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte
82 * and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte
84 ret = regmap_bulk_read(data->regmap,
85 ADXL345_REG_DATA_AXIS(chan->address),
86 &accel, sizeof(accel));
90 *val = sign_extend32(le16_to_cpu(accel), 12);
92 case IIO_CHAN_INFO_SCALE:
94 *val2 = adxl345_uscale;
96 return IIO_VAL_INT_PLUS_MICRO;
102 static const struct iio_info adxl345_info = {
103 .read_raw = adxl345_read_raw,
106 int adxl345_core_probe(struct device *dev, struct regmap *regmap,
109 struct adxl345_data *data;
110 struct iio_dev *indio_dev;
114 ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val);
116 dev_err(dev, "Error reading device ID: %d\n", ret);
120 if (regval != ADXL345_DEVID) {
121 dev_err(dev, "Invalid device ID: %x, expected %x\n",
122 regval, ADXL345_DEVID);
126 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
130 data = iio_priv(indio_dev);
131 dev_set_drvdata(dev, indio_dev);
132 data->regmap = regmap;
133 /* Enable full-resolution mode */
134 data->data_range = ADXL345_DATA_FORMAT_FULL_RES;
136 ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
139 dev_err(dev, "Failed to set data range: %d\n", ret);
143 indio_dev->dev.parent = dev;
144 indio_dev->name = name;
145 indio_dev->info = &adxl345_info;
146 indio_dev->modes = INDIO_DIRECT_MODE;
147 indio_dev->channels = adxl345_channels;
148 indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
150 /* Enable measurement mode */
151 ret = regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
152 ADXL345_POWER_CTL_MEASURE);
154 dev_err(dev, "Failed to enable measurement mode: %d\n", ret);
158 ret = iio_device_register(indio_dev);
160 dev_err(dev, "iio_device_register failed: %d\n", ret);
161 regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
162 ADXL345_POWER_CTL_STANDBY);
167 EXPORT_SYMBOL_GPL(adxl345_core_probe);
169 int adxl345_core_remove(struct device *dev)
171 struct iio_dev *indio_dev = dev_get_drvdata(dev);
172 struct adxl345_data *data = iio_priv(indio_dev);
174 iio_device_unregister(indio_dev);
176 return regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
177 ADXL345_POWER_CTL_STANDBY);
179 EXPORT_SYMBOL_GPL(adxl345_core_remove);
181 MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
182 MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
183 MODULE_LICENSE("GPL v2");