1 .. SPDX-License-Identifier: GPL-2.0 2 3 =============== 4 ADXL380 driver 5 =============== 6 7 This driver supports Analog Device's ADXL380/382 on SPI/I2C bus. 8 9 1. Supported devices 10 ==================== 11 12 * `ADXL380 <https://www.analog.com/ADXL380>`_ 13 * `ADXL382 <https://www.analog.com/ADXL382>`_ 14 15 The ADXL380/ADXL382 is a low noise density, low power, 3-axis accelerometer with 16 selectable measurement ranges. The ADXL380 supports the ±4 g, ±8 g, and ±16 g 17 ranges, and the ADXL382 supports ±15 g, ±30 g, and ±60 g ranges. 18 19 2. Device attributes 20 ==================== 21 22 Accelerometer measurements are always provided. 23 24 Temperature data are also provided. This data can be used to monitor the 25 internal system temperature or to improve the temperature stability of the 26 device via calibration. 27 28 Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``, 29 where X is the IIO index of the device. Under these folders reside a set of 30 device files, depending on the characteristics and features of the hardware 31 device in questions. These files are consistently generalized and documented in 32 the IIO ABI documentation. 33 34 The following tables show the adxl380 related device files, found in the 35 specific device folder path ``/sys/bus/iio/devices/iio:deviceX``. 36 37 +---------------------------------------------------+----------------------------------------------------------+ 38 | 3-Axis Accelerometer related device files | Description | 39 +---------------------------------------------------+----------------------------------------------------------+ 40 | in_accel_scale | Scale for the accelerometer channels. | 41 +---------------------------------------------------+----------------------------------------------------------+ 42 | in_accel_filter_high_pass_3db_frequency | Low pass filter bandwidth. | 43 +---------------------------------------------------+----------------------------------------------------------+ 44 | in_accel_filter_high_pass_3db_frequency_available | Available low pass filter bandwidth configurations. | 45 +---------------------------------------------------+----------------------------------------------------------+ 46 | in_accel_filter_low_pass_3db_frequency | High pass filter bandwidth. | 47 +---------------------------------------------------+----------------------------------------------------------+ 48 | in_accel_filter_low_pass_3db_frequency_available | Available high pass filter bandwidth configurations. | 49 +---------------------------------------------------+----------------------------------------------------------+ 50 | in_accel_x_calibbias | Calibration offset for the X-axis accelerometer channel. | 51 +---------------------------------------------------+----------------------------------------------------------+ 52 | in_accel_x_raw | Raw X-axis accelerometer channel value. | 53 +---------------------------------------------------+----------------------------------------------------------+ 54 | in_accel_y_calibbias | y-axis acceleration offset correction | 55 +---------------------------------------------------+----------------------------------------------------------+ 56 | in_accel_y_raw | Raw Y-axis accelerometer channel value. | 57 +---------------------------------------------------+----------------------------------------------------------+ 58 | in_accel_z_calibbias | Calibration offset for the Z-axis accelerometer channel. | 59 +---------------------------------------------------+----------------------------------------------------------+ 60 | in_accel_z_raw | Raw Z-axis accelerometer channel value. | 61 +---------------------------------------------------+----------------------------------------------------------+ 62 63 +----------------------------------+--------------------------------------------+ 64 | Temperature sensor related files | Description | 65 +----------------------------------+--------------------------------------------+ 66 | in_temp_raw | Raw temperature channel value. | 67 +----------------------------------+--------------------------------------------+ 68 | in_temp_offset | Offset for the temperature sensor channel. | 69 +----------------------------------+--------------------------------------------+ 70 | in_temp_scale | Scale for the temperature sensor channel. | 71 +----------------------------------+--------------------------------------------+ 72 73 +------------------------------+----------------------------------------------+ 74 | Miscellaneous device files | Description | 75 +------------------------------+----------------------------------------------+ 76 | name | Name of the IIO device. | 77 +------------------------------+----------------------------------------------+ 78 | sampling_frequency | Currently selected sample rate. | 79 +------------------------------+----------------------------------------------+ 80 | sampling_frequency_available | Available sampling frequency configurations. | 81 +------------------------------+----------------------------------------------+ 82 83 Channels processed values 84 ------------------------- 85 86 A channel value can be read from its _raw attribute. The value returned is the 87 raw value as reported by the devices. To get the processed value of the channel, 88 apply the following formula: 89 90 .. code-block:: bash 91 92 processed value = (_raw + _offset) * _scale 93 94 Where _offset and _scale are device attributes. If no _offset attribute is 95 present, simply assume its value is 0. 96 97 The adis16475 driver offers data for 2 types of channels, the table below shows 98 the measurement units for the processed value, which are defined by the IIO 99 framework: 100 101 +-------------------------------------+---------------------------+ 102 | Channel type | Measurement unit | 103 +-------------------------------------+---------------------------+ 104 | Acceleration on X, Y, and Z axis | Meters per Second squared | 105 +-------------------------------------+---------------------------+ 106 | Temperature | Millidegrees Celsius | 107 +-------------------------------------+---------------------------+ 108 109 Usage examples 110 -------------- 111 112 Show device name: 113 114 .. code-block:: bash 115 116 root:/sys/bus/iio/devices/iio:device0> cat name 117 adxl382 118 119 Show accelerometer channels value: 120 121 .. code-block:: bash 122 123 root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw 124 -1771 125 root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw 126 282 127 root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw 128 -1523 129 root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale 130 0.004903325 131 132 - X-axis acceleration = in_accel_x_raw * in_accel_scale = −8.683788575 m/s^2 133 - Y-axis acceleration = in_accel_y_raw * in_accel_scale = 1.38273765 m/s^2 134 - Z-axis acceleration = in_accel_z_raw * in_accel_scale = -7.467763975 m/s^2 135 136 Set calibration offset for accelerometer channels: 137 138 .. code-block:: bash 139 140 root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias 141 0 142 143 root:/sys/bus/iio/devices/iio:device0> echo 50 > in_accel_x_calibbias 144 root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias 145 50 146 147 Set sampling frequency: 148 149 .. code-block:: bash 150 151 root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency 152 16000 153 root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency_available 154 16000 32000 64000 155 156 root:/sys/bus/iio/devices/iio:device0> echo 32000 > sampling_frequency 157 root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency 158 32000 159 160 Set low pass filter bandwidth for accelerometer channels: 161 162 .. code-block:: bash 163 164 root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency 165 32000 166 root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency_available 167 32000 8000 4000 2000 168 169 root:/sys/bus/iio/devices/iio:device0> echo 2000 > in_accel_filter_low_pass_3db_frequency 170 root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency 171 2000 172 173 3. Device buffers 174 ================= 175 176 This driver supports IIO buffers. 177 178 All devices support retrieving the raw acceleration and temperature measurements 179 using buffers. 180 181 Usage examples 182 -------------- 183 184 Select channels for buffer read: 185 186 .. code-block:: bash 187 188 root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_x_en 189 root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_y_en 190 root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_z_en 191 root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp_en 192 193 Set the number of samples to be stored in the buffer: 194 195 .. code-block:: bash 196 197 root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length 198 199 Enable buffer readings: 200 201 .. code-block:: bash 202 203 root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable 204 205 Obtain buffered data: 206 207 .. code-block:: bash 208 209 root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0 210 ... 211 002bc300 f7 e7 00 a8 fb c5 24 80 f7 e7 01 04 fb d6 24 80 |......$.......$.| 212 002bc310 f7 f9 00 ab fb dc 24 80 f7 c3 00 b8 fb e2 24 80 |......$.......$.| 213 002bc320 f7 fb 00 bb fb d1 24 80 f7 b1 00 5f fb d1 24 80 |......$...._..$.| 214 002bc330 f7 c4 00 c6 fb a6 24 80 f7 a6 00 68 fb f1 24 80 |......$....h..$.| 215 002bc340 f7 b8 00 a3 fb e7 24 80 f7 9a 00 b1 fb af 24 80 |......$.......$.| 216 002bc350 f7 b1 00 67 fb ee 24 80 f7 96 00 be fb 92 24 80 |...g..$.......$.| 217 002bc360 f7 ab 00 7a fc 1b 24 80 f7 b6 00 ae fb 76 24 80 |...z..$......v$.| 218 002bc370 f7 ce 00 a3 fc 02 24 80 f7 c0 00 be fb 8b 24 80 |......$.......$.| 219 002bc380 f7 c3 00 93 fb d0 24 80 f7 ce 00 d8 fb c8 24 80 |......$.......$.| 220 002bc390 f7 bd 00 c0 fb 82 24 80 f8 00 00 e8 fb db 24 80 |......$.......$.| 221 002bc3a0 f7 d8 00 d3 fb b4 24 80 f8 0b 00 e5 fb c3 24 80 |......$.......$.| 222 002bc3b0 f7 eb 00 c8 fb 92 24 80 f7 e7 00 ea fb cb 24 80 |......$.......$.| 223 002bc3c0 f7 fd 00 cb fb 94 24 80 f7 e3 00 f2 fb b8 24 80 |......$.......$.| 224 ... 225 226 See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered 227 data is structured. 228 229 4. IIO Interfacing Tools 230 ======================== 231 232 See ``Documentation/iio/iio_tools.rst`` for the description of the available IIO 233 interfacing tools.
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