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.
11 #include <linux/module.h>
12 #include <linux/regmap.h>
14 #include <linux/iio/iio.h>
18 #define ADXL345_REG_DEVID 0x00
19 #define ADXL345_REG_POWER_CTL 0x2D
20 #define ADXL345_REG_DATA_FORMAT 0x31
21 #define ADXL345_REG_DATAX0 0x32
22 #define ADXL345_REG_DATAY0 0x34
23 #define ADXL345_REG_DATAZ0 0x36
25 #define ADXL345_POWER_CTL_MEASURE BIT(3)
26 #define ADXL345_POWER_CTL_STANDBY 0x00
28 #define ADXL345_DATA_FORMAT_FULL_RES BIT(3) /* Up to 13-bits resolution */
29 #define ADXL345_DATA_FORMAT_2G 0
30 #define ADXL345_DATA_FORMAT_4G 1
31 #define ADXL345_DATA_FORMAT_8G 2
32 #define ADXL345_DATA_FORMAT_16G 3
34 #define ADXL345_DEVID 0xE5
37 * In full-resolution mode, scale factor is maintained at ~4 mg/LSB
40 * At +/- 16g with 13-bit resolution, scale is computed as:
41 * (16 + 16) * 9.81 / (2^13 - 1) = 0.0383
43 static const int adxl345_uscale = 38300;
46 struct regmap *regmap;
50 #define ADXL345_CHANNEL(reg, axis) { \
53 .channel2 = IIO_MOD_##axis, \
55 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
56 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
59 static const struct iio_chan_spec adxl345_channels[] = {
60 ADXL345_CHANNEL(ADXL345_REG_DATAX0, X),
61 ADXL345_CHANNEL(ADXL345_REG_DATAY0, Y),
62 ADXL345_CHANNEL(ADXL345_REG_DATAZ0, Z),
65 static int adxl345_read_raw(struct iio_dev *indio_dev,
66 struct iio_chan_spec const *chan,
67 int *val, int *val2, long mask)
69 struct adxl345_data *data = iio_priv(indio_dev);
74 case IIO_CHAN_INFO_RAW:
76 * Data is stored in adjacent registers:
77 * ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte
78 * and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte
80 ret = regmap_bulk_read(data->regmap, chan->address, ®val,
85 *val = sign_extend32(le16_to_cpu(regval), 12);
87 case IIO_CHAN_INFO_SCALE:
89 *val2 = adxl345_uscale;
91 return IIO_VAL_INT_PLUS_MICRO;
97 static const struct iio_info adxl345_info = {
98 .read_raw = adxl345_read_raw,
101 int adxl345_core_probe(struct device *dev, struct regmap *regmap,
104 struct adxl345_data *data;
105 struct iio_dev *indio_dev;
109 ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val);
111 dev_err(dev, "Error reading device ID: %d\n", ret);
115 if (regval != ADXL345_DEVID) {
116 dev_err(dev, "Invalid device ID: %x, expected %x\n",
117 regval, ADXL345_DEVID);
121 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
125 data = iio_priv(indio_dev);
126 dev_set_drvdata(dev, indio_dev);
127 data->regmap = regmap;
128 /* Enable full-resolution mode */
129 data->data_range = ADXL345_DATA_FORMAT_FULL_RES;
131 ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
134 dev_err(dev, "Failed to set data range: %d\n", ret);
138 indio_dev->dev.parent = dev;
139 indio_dev->name = name;
140 indio_dev->info = &adxl345_info;
141 indio_dev->modes = INDIO_DIRECT_MODE;
142 indio_dev->channels = adxl345_channels;
143 indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
145 /* Enable measurement mode */
146 ret = regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
147 ADXL345_POWER_CTL_MEASURE);
149 dev_err(dev, "Failed to enable measurement mode: %d\n", ret);
153 ret = iio_device_register(indio_dev);
155 dev_err(dev, "iio_device_register failed: %d\n", ret);
156 regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
157 ADXL345_POWER_CTL_STANDBY);
162 EXPORT_SYMBOL_GPL(adxl345_core_probe);
164 int adxl345_core_remove(struct device *dev)
166 struct iio_dev *indio_dev = dev_get_drvdata(dev);
167 struct adxl345_data *data = iio_priv(indio_dev);
169 iio_device_unregister(indio_dev);
171 return regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
172 ADXL345_POWER_CTL_STANDBY);
174 EXPORT_SYMBOL_GPL(adxl345_core_remove);
176 MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
177 MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
178 MODULE_LICENSE("GPL v2");