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diff --git a/Documentation/iio/adxl313.rst b/Documentation/iio/adxl313.rst new file mode 100644 index 000000000000..966e72c0109a --- /dev/null +++ b/Documentation/iio/adxl313.rst @@ -0,0 +1,293 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +ADXL313 driver +=============== + +This driver supports Analog Device's ADXL313 on SPI/I2C bus. + +1. Supported devices +==================== + +* `ADXL313 <https://www.analog.com/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. + +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. | ++---------------------------------------+----------------------------------------------+ + +The iio event related settings, found in ``/sys/bus/iio/devices/iio:deviceX/events``. + ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_mag_adaptive_falling_period | AC coupled inactivity time. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_mag_adaptive_falling_value | AC coupled inactivity threshold. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_mag_adaptive_rising_value | AC coupled activity threshold. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_mag_falling_period | Inactivity time. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_mag_falling_value | Inactivity threshold. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_mag_rising_value | Activity threshold. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_x\&y\&z_mag_adaptive_falling_en | Enable or disable AC coupled inactivity events. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_x\|y\|z_mag_adaptive_rising_en | Enable or disable AC coupled activity events. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_x\&y\&z_mag_falling_en | Enable or disable inactivity events. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_x\|y\|z_mag_rising_en | Enable or disable activity events. | ++---------------------------------------------------+----------------------------------------------------------+ + +The default coupling is DC coupled events. In this case the threshold will +be in place as such, where for the AC coupled case an adaptive threshold +(described in the datasheet) will be applied by the sensor. In general activity, +i.e. ``ACTIVITY`` or ``ACTIVITY_AC`` and inactivity i.e. ``INACTIVITY`` or +``INACTIVITY_AC``, will be linked with auto-sleep enabled when both are enabled. +This means in particular ``ACTIVITY`` can also be linked to ``INACTIVITY_AC`` +and vice versa, without problem. + +Note here, that ``ACTIVITY`` and ``ACTIVITY_AC`` are mutually exclusive. This +means, that the most recent configuration will be set. For instance, if +``ACTIVITY`` is enabled, and ``ACTIVITY_AC`` will be enabled, the sensor driver +will have ``ACTIVITY`` disabled, but ``ACTIVITY_AC`` enabled. The same is valid +for inactivity. In case of turning off an event, it has to match to what is +actually enabled, i.e. enabling ``ACTIVITY_AC`` and then disabling ``ACTIVITY`` +is simply ignored as it is already disabled. Or, as if it was any other not +enabled event, too. + +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:: + + 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 + +The accelerometer values will be: + +- 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, that 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 and triggers +============================== + +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.....| + ... + +Enabling activity detection: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1.28125 > ./events/in_accel_mag_rising_value + root:/sys/bus/iio/devices/iio:device0> echo 1 > ./events/in_accel_x\|y\|z_mag_rising_en + + root:/sys/bus/iio/devices/iio:device0> iio_event_monitor adxl313 + Found IIO device with name adxl313 with device number 0 + <only while moving the sensor> + Event: time: 1748795762298351281, type: accel(x|y|z), channel: 0, evtype: mag, direction: rising + Event: time: 1748795762302653704, type: accel(x|y|z), channel: 0, evtype: mag, direction: rising + Event: time: 1748795762304340726, type: accel(x|y|z), channel: 0, evtype: mag, direction: rising + ... + +Disabling activity detection: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 0 > ./events/in_accel_x\|y\|z_mag_rising_en + root:/sys/bus/iio/devices/iio:device0> iio_event_monitor adxl313 + <nothing> + +Enabling inactivity detection: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1.234375 > ./events/in_accel_mag_falling_value + root:/sys/bus/iio/devices/iio:device0> echo 5 > ./events/in_accel_mag_falling_period + root:/sys/bus/iio/devices/iio:device0> echo 1 > ./events/in_accel_x\&y\&z_mag_falling_en + + root:/sys/bus/iio/devices/iio:device0> iio_event_monitor adxl313 + Found IIO device with name adxl313 with device number 0 + Event: time: 1748796324115962975, type: accel(x&y&z), channel: 0, evtype: mag, direction: falling + Event: time: 1748796329329981772, type: accel(x&y&z), channel: 0, evtype: mag, direction: falling + Event: time: 1748796334543399706, type: accel(x&y&z), channel: 0, evtype: mag, direction: falling + ... + <every 5s now indicates inactivity> + +Now, enabling activity, e.g. the AC coupled counter-part ``ACTIVITY_AC`` + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1.28125 > ./events/in_accel_mag_rising_value + root:/sys/bus/iio/devices/iio:device0> echo 1 > ./events/in_accel_x\|y\|z_mag_rising_en + + root:/sys/bus/iio/devices/iio:device0> iio_event_monitor adxl313 + Found IIO device with name adxl313 with device number 0 + <some activity with the sensor> + Event: time: 1748796880354686777, type: accel(x|y|z), channel: 0, evtype: mag_adaptive, direction: rising + <5s of inactivity, then> + Event: time: 1748796885543252017, type: accel(x&y&z), channel: 0, evtype: mag, direction: falling + <some other activity detected by accelerating the sensor> + Event: time: 1748796887756634678, type: accel(x|y|z), channel: 0, evtype: mag_adaptive, direction: rising + <again, 5s of inactivity> + Event: time: 1748796892964368352, type: accel(x&y&z), channel: 0, evtype: mag, direction: falling + <stays like this until next activity in auto-sleep> + +Note, when AC coupling is in place, the event type will be of ``mag_adaptive``. +AC- or DC-coupled (the default) events are used similarly. + +4. IIO Interfacing Tools +======================== + +See Documentation/iio/iio_tools.rst for the description of the available IIO +interfacing tools. |