1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
/*
* ADXL345 3-Axis Digital Accelerometer IIO core driver
*
* Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com>
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf
*/
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include "adxl345.h"
#define ADXL345_REG_DEVID 0x00
#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_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;
struct adxl345_data {
struct regmap *regmap;
u8 data_range;
};
#define ADXL345_CHANNEL(reg, axis) { \
.type = IIO_ACCEL, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.address = reg, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
}
static const struct iio_chan_spec adxl345_channels[] = {
ADXL345_CHANNEL(ADXL345_REG_DATAX0, X),
ADXL345_CHANNEL(ADXL345_REG_DATAY0, Y),
ADXL345_CHANNEL(ADXL345_REG_DATAZ0, 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 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, chan->address, ®val,
sizeof(regval));
if (ret < 0)
return ret;
*val = sign_extend32(le16_to_cpu(regval), 12);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 0;
*val2 = adxl345_uscale;
return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
}
static const struct iio_info adxl345_info = {
.read_raw = adxl345_read_raw,
};
int adxl345_core_probe(struct device *dev, struct regmap *regmap,
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);
dev_set_drvdata(dev, indio_dev);
data->regmap = regmap;
/* 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->dev.parent = dev;
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 = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(dev, "iio_device_register failed: %d\n", ret);
regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
ADXL345_POWER_CTL_STANDBY);
}
return ret;
}
EXPORT_SYMBOL_GPL(adxl345_core_probe);
int adxl345_core_remove(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct adxl345_data *data = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
return regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
ADXL345_POWER_CTL_STANDBY);
}
EXPORT_SYMBOL_GPL(adxl345_core_remove);
MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
MODULE_LICENSE("GPL v2");
|
