Add documentation for the ADXL313 accelerometer driver. Signed-off-by: Lothar Rubusch --- Documentation/iio/adxl313.rst | 196 ++++++++++++++++++++++++++++++++++ Documentation/iio/index.rst | 1 + 2 files changed, 197 insertions(+) create mode 100644 Documentation/iio/adxl313.rst diff --git a/Documentation/iio/adxl313.rst b/Documentation/iio/adxl313.rst new file mode 100644 index 000000000000..8c4e2d141594 --- /dev/null +++ b/Documentation/iio/adxl313.rst @@ -0,0 +1,196 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +ADXL313 driver +=============== + +This driver supports Analog Device's ADXL313 on SPI/I2C bus. + +1. Supported devices +==================== + +* `ADXL313 `_ + +The ADXL313is a low noise density, low power, 3-axis accelerometer with +selectable measurement ranges. The ADXL313 supports the ±0.5 g, ±1 g, ±2 g and +±4 g ranges. + +2. Device attributes +==================== + +Accelerometer measurements are always provided. + +Temperature data are also provided. This data can be used to monitor the +internal system temperature or to improve the temperature stability of the +device via calibration. + +Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``, +where X is the IIO index of the device. Under these folders reside a set of +device files, depending on the characteristics and features of the hardware +device in questions. These files are consistently generalized and documented in +the IIO ABI documentation. + +The following tables show the adxl313 related device files, found in the +specific device folder path ``/sys/bus/iio/devices/iio:deviceX``. + ++---------------------------------------------------+----------------------------------------------------------+ +| 3-Axis Accelerometer related device files | Description | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_scale | Scale for the accelerometer channels. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_x_calibbias | Calibration offset for the X-axis accelerometer channel. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_x_raw | Raw X-axis accelerometer channel value. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_y_calibbias | y-axis acceleration offset correction | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_y_raw | Raw Y-axis accelerometer channel value. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_z_calibbias | Calibration offset for the Z-axis accelerometer channel. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_z_raw | Raw Z-axis accelerometer channel value. | ++---------------------------------------------------+----------------------------------------------------------+ + ++---------------------------------------+----------------------------------------------+ +| Miscellaneous device files | Description | ++---------------------------------------+----------------------------------------------+ +| name | Name of the IIO device. | ++---------------------------------------+----------------------------------------------+ +| in_accel_sampling_frequency | Currently selected sample rate. | ++---------------------------------------+----------------------------------------------+ +| in_accel_sampling_frequency_available | Available sampling frequency configurations. | ++---------------------------------------+----------------------------------------------+ + +Channels processed values +------------------------- + +A channel value can be read from its _raw attribute. The value returned is the +raw value as reported by the devices. To get the processed value of the channel, +apply the following formula: + +.. code-block:: bash + + processed value = (_raw + _offset) * _scale + +Where _offset and _scale are device attributes. If no _offset attribute is +present, simply assume its value is 0. + +The ADXL313 driver offers data for a single types of channels, the table below +shows the measurement units for the processed value, which are defined by the +IIO framework: + ++-------------------------------------+---------------------------+ +| Channel type | Measurement unit | ++-------------------------------------+---------------------------+ +| Acceleration on X, Y, and Z axis | Meters per Second squared | ++-------------------------------------+---------------------------+ + +Usage examples +-------------- + +Show device name: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat name + adxl313 + +Show accelerometer channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw + 2 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw + -57 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw + 2 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale + 0.009576806 + +- X-axis acceleration = in_accel_x_raw * in_accel_scale = 0.0191536 m/s^2 +- Y-axis acceleration = in_accel_y_raw * in_accel_scale = -0.5458779 m/s^2 +- Z-axis acceleration = in_accel_z_raw * in_accel_scale = 0.0191536 m/s^2 + +Set calibration offset for accelerometer channels. Note, the calibration will be +rounded according to the graduation of LSB units: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo 50 > in_accel_x_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 48 + +Set sampling frequency: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_sampling_frequency + 100.000000 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_sampling_frequency_available + 6.250000 12.500000 25.000000 50.000000 100.000000 200.000000 400.000000 800.000000 1600.000000 3200.000000 + + root:/sys/bus/iio/devices/iio:device0> echo 400 > in_accel_sampling_frequency + root:/sys/bus/iio/devices/iio:device0> cat in_accel_sampling_frequency + 400.000000 + +3. Device buffers +================= + +This driver supports IIO buffers. + +All devices support retrieving the raw acceleration measurements using buffers. + +Usage examples +-------------- + +Select channels for buffer read: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_x_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_y_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_z_en + +Set the number of samples to be stored in the buffer: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length + +Enable buffer readings: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable + +Obtain buffered data: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0 + ... + 000000d0 01 fc 31 00 c7 ff 03 fc 31 00 c7 ff 04 fc 33 00 |..1.....1.....3.| + 000000e0 c8 ff 03 fc 32 00 c5 ff ff fc 32 00 c7 ff 0a fc |....2.....2.....| + 000000f0 30 00 c8 ff 06 fc 33 00 c7 ff 01 fc 2f 00 c8 ff |0.....3...../...| + 00000100 02 fc 32 00 c6 ff 04 fc 33 00 c8 ff 05 fc 33 00 |..2.....3.....3.| + 00000110 ca ff 02 fc 31 00 c7 ff 02 fc 30 00 c9 ff 09 fc |....1.....0.....| + 00000120 35 00 c9 ff 08 fc 35 00 c8 ff 02 fc 31 00 c5 ff |5.....5.....1...| + 00000130 03 fc 32 00 c7 ff 04 fc 32 00 c7 ff 02 fc 31 00 |..2.....2.....1.| + 00000140 c7 ff 08 fc 30 00 c7 ff 02 fc 32 00 c5 ff ff fc |....0.....2.....| + 00000150 31 00 c5 ff 04 fc 31 00 c8 ff 03 fc 32 00 c8 ff |1.....1.....2...| + 00000160 01 fc 31 00 c7 ff 05 fc 31 00 c3 ff 04 fc 31 00 |..1.....1.....1.| + 00000170 c5 ff 04 fc 30 00 c7 ff 03 fc 31 00 c9 ff 03 fc |....0.....1.....| + ... + +See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered +data is structured. + +4. IIO Interfacing Tools +======================== + +See ``Documentation/iio/iio_tools.rst`` for the description of the available IIO +interfacing tools. diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst index 2d6afc5a8ed5..c106402a91f7 100644 --- a/Documentation/iio/index.rst +++ b/Documentation/iio/index.rst @@ -31,6 +31,7 @@ Industrial I/O Kernel Drivers adis16475 adis16480 adis16550 + adxl313 adxl380 bno055 ep93xx_adc -- 2.39.5