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diff --git a/Documentation/iio/adis16475.rst b/Documentation/iio/adis16475.rst new file mode 100644 index 0000000000..130f9e97cc --- /dev/null +++ b/Documentation/iio/adis16475.rst @@ -0,0 +1,403 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +ADIS16475 driver +================ + +This driver supports Analog Device's IMUs on SPI bus. + +1. Supported devices +==================== + +* `ADIS16465 <https://www.analog.com/ADIS16465>`_ +* `ADIS16467 <https://www.analog.com/ADIS16467>`_ +* `ADIS16470 <https://www.analog.com/ADIS16470>`_ +* `ADIS16475 <https://www.analog.com/ADIS16475>`_ +* `ADIS16477 <https://www.analog.com/ADIS16477>`_ +* `ADIS16500 <https://www.analog.com/ADIS16500>`_ +* `ADIS16505 <https://www.analog.com/ADIS16505>`_ +* `ADIS16507 <https://www.analog.com/ADIS16507>`_ + +Each supported device is a precision, miniature microelectromechanical system +(MEMS) inertial measurement unit (IMU) that includes a triaxial gyroscope and a +triaxial accelerometer. Each inertial sensor in the IMU device combines with +signal conditioning that optimizes dynamic performance. The factory calibration +characterizes each sensor for sensitivity, bias, alignment, linear acceleration +(gyroscope bias), and point of percussion (accelerometer location). As a result, +each sensor has dynamic compensation formulas that provide accurate sensor +measurements over a broad set of conditions. + +2. Device attributes +==================== + +Accelerometer, gyroscope measurements are always provided. Furthermore, the +driver offers the capability to retrieve the delta angle and the delta velocity +measurements computed by the device. + +The delta angle measurements represent a calculation of angular displacement +between each sample update, while the delta velocity measurements represent a +calculation of linear velocity change between each sample update. + +Finally, temperature data are provided which show a coarse measurement of +the temperature inside of the IMU device. This data is most useful for +monitoring relative changes in the thermal environment. + +The signal chain of each inertial sensor (accelerometers and gyroscopes) +includes the application of unique correction formulas, which are derived from +extensive characterization of bias, sensitivity, alignment, response to linear +acceleration (gyroscopes), and point of percussion (accelerometer location) +over a temperature range of −40°C to +85°C, for each ADIS device. These +correction formulas are not accessible, but users do have the opportunity to +adjust the bias for each sensor individually through the calibbias attribute. + +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 adis16475 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 | Calibration offset for the Y-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| 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. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_scale | Scale for delta velocity channels. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_x_raw | Raw X-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_y_raw | Raw Y-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_z_raw | Raw Z-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ + ++---------------------------------------+------------------------------------------------------+ +| 3-Axis Gyroscope related device files | Description | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_scale | Scale for the gyroscope channels. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_x_calibbias | Calibration offset for the X-axis gyroscope channel. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_x_raw | Raw X-axis gyroscope channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_y_calibbias | Calibration offset for the Y-axis gyroscope channel. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_y_raw | Raw Y-axis gyroscope channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_z_calibbias | Calibration offset for the Z-axis gyroscope channel. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_z_raw | Raw Z-axis gyroscope channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_deltaangl_scale | Scale for delta angle channels. | ++---------------------------------------+------------------------------------------------------+ +| in_deltaangl_x_raw | Raw X-axis delta angle channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_deltaangl_y_raw | Raw Y-axis delta angle channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_deltaangl_z_raw | Raw Z-axis delta angle channel value. | ++---------------------------------------+------------------------------------------------------+ + ++----------------------------------+-------------------------------------------+ +| Temperature sensor related files | Description | ++----------------------------------+-------------------------------------------+ +| in_temp0_raw | Raw temperature channel value. | ++----------------------------------+-------------------------------------------+ +| in_temp0_scale | Scale for the temperature sensor channel. | ++----------------------------------+-------------------------------------------+ + ++-------------------------------+---------------------------------------------------------+ +| Miscellaneous device files | Description | ++-------------------------------+---------------------------------------------------------+ +| name | Name of the IIO device. | ++-------------------------------+---------------------------------------------------------+ +| sampling_frequency | Currently selected sample rate. | ++-------------------------------+---------------------------------------------------------+ +| filter_low_pass_3db_frequency | Bandwidth for the accelerometer and gyroscope channels. | ++-------------------------------+---------------------------------------------------------+ + +The following table shows the adis16475 related device debug files, found in the +specific device debug folder path ``/sys/kernel/debug/iio/iio:deviceX``. + ++----------------------+-------------------------------------------------------------------------+ +| Debugfs device files | Description | ++----------------------+-------------------------------------------------------------------------+ +| serial_number | The serial number of the chip in hexadecimal format. | ++----------------------+-------------------------------------------------------------------------+ +| product_id | Chip specific product id (e.g. 16475, 16500, 16505, etc.). | ++----------------------+-------------------------------------------------------------------------+ +| flash_count | The number of flash writes performed on the device. | ++----------------------+-------------------------------------------------------------------------+ +| firmware_revision | String containing the firmware revision in the following format ##.##. | ++----------------------+-------------------------------------------------------------------------+ +| firmware_date | String containing the firmware date in the following format mm-dd-yyyy. | ++----------------------+-------------------------------------------------------------------------+ + +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 adis16475 driver offers data for 5 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 | ++-------------------------------------+---------------------------+ +| Angular velocity on X, Y and Z axis | Radians per second | ++-------------------------------------+---------------------------+ +| Delta velocity on X. Y, and Z axis | Meters per Second | ++-------------------------------------+---------------------------+ +| Delta angle on X, Y, and Z axis | Radians | ++-------------------------------------+---------------------------+ +| Temperature | Millidegrees Celsius | ++-------------------------------------+---------------------------+ + +Usage examples +-------------- + +Show device name: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat name + adis16505-2 + +Show accelerometer channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw + -275924 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw + -30142222 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw + 261265769 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale + 0.000000037 + +- X-axis acceleration = in_accel_x_raw * in_accel_scale = −0.010209188 m/s^2 +- Y-axis acceleration = in_accel_y_raw * in_accel_scale = −1.115262214 m/s^2 +- Z-axis acceleration = in_accel_z_raw * in_accel_scale = 9.666833453 m/s^2 + +Show gyroscope channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw + -3324626 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw + 1336980 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw + -602983 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale + 0.000000006 + +- X-axis angular velocity = in_anglvel_x_raw * in_anglvel_scale = −0.019947756 rad/s +- Y-axis angular velocity = in_anglvel_y_raw * in_anglvel_scale = 0.00802188 rad/s +- Z-axis angular velocity = in_anglvel_z_raw * in_anglvel_scale = −0.003617898 rad/s + +Set calibration offset for accelerometer channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo 5000 > in_accel_x_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 5000 + +Set calibration offset for gyroscope channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo -5000 > in_anglvel_y_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias + -5000 + +Set sampling frequency: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency + 2000.000000 + + root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency + 1000.000000 + +Set bandwidth for accelerometer and gyroscope: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat filter_low_pass_3db_frequency + 720 + + root:/sys/bus/iio/devices/iio:device0> echo 360 > filter_low_pass_3db_frequency + root:/sys/bus/iio/devices/iio:device0> cat filter_low_pass_3db_frequency + 360 + +Show serial number: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat serial_number + 0x04f9 + +Show product id: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat product_id + 16505 + +Show flash count: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat flash_count + 150 + +Show firmware revision: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision + 1.6 + +Show firmware date: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat firmware_date + 06-27-2019 + +3. Device buffers +================= + +This driver supports IIO buffers. + +All devices support retrieving the raw acceleration, gyroscope and temperature +measurements using buffers. + +The following device families also support retrieving the delta velocity, delta +angle and temperature measurements using buffers: + +- ADIS16477 +- ADIS16500 +- ADIS16505 +- ADIS16507 + +However, when retrieving acceleration or gyroscope data using buffers, delta +readings will not be available and vice versa. + +Usage examples +-------------- + +Set device trigger in current_trigger, if not already set: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger + + root:/sys/bus/iio/devices/iio:device0> echo adis16505-2-dev0 > trigger/current_trigger + root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger + adis16505-2-dev0 + +Select channels for buffer read: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_x_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_y_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_z_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp0_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 + ... + 00001680 01 1f 00 00 ff ff fe ef 00 00 47 bf 00 03 35 55 |..........G...5U| + 00001690 01 1f 00 00 ff ff ff d9 00 00 46 f1 00 03 35 35 |..........F...55| + 000016a0 01 1f 00 00 ff ff fe fc 00 00 46 cb 00 03 35 7b |..........F...5{| + 000016b0 01 1f 00 00 ff ff fe 41 00 00 47 0d 00 03 35 8b |.......A..G...5.| + 000016c0 01 1f 00 00 ff ff fe 37 00 00 46 b4 00 03 35 90 |.......7..F...5.| + 000016d0 01 1d 00 00 ff ff fe 5a 00 00 45 d7 00 03 36 08 |.......Z..E...6.| + 000016e0 01 1b 00 00 ff ff fe fb 00 00 45 e7 00 03 36 60 |..........E...6`| + 000016f0 01 1a 00 00 ff ff ff 17 00 00 46 bc 00 03 36 de |..........F...6.| + 00001700 01 1a 00 00 ff ff fe 59 00 00 46 d7 00 03 37 b8 |.......Y..F...7.| + 00001710 01 1a 00 00 ff ff fe ae 00 00 46 95 00 03 37 ba |..........F...7.| + 00001720 01 1a 00 00 ff ff fe c5 00 00 46 63 00 03 37 9f |..........Fc..7.| + 00001730 01 1a 00 00 ff ff fe 55 00 00 46 89 00 03 37 c1 |.......U..F...7.| + 00001740 01 1a 00 00 ff ff fe 31 00 00 46 aa 00 03 37 f7 |.......1..F...7.| + ... + +See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered +data is structured. + +4. IIO Interfacing Tools +======================== + +Linux Kernel Tools +------------------ + +Linux Kernel provides some userspace tools that can be used to retrieve data +from IIO sysfs: + +* lsiio: example application that provides a list of IIO devices and triggers +* iio_event_monitor: example application that reads events from an IIO device + and prints them +* iio_generic_buffer: example application that reads data from buffer +* iio_utils: set of APIs, typically used to access sysfs files. + +LibIIO +------ + +LibIIO is a C/C++ library that provides generic access to IIO devices. The +library abstracts the low-level details of the hardware, and provides a simple +yet complete programming interface that can be used for advanced projects. + +For more information about LibIIO, please see: +https://github.com/analogdevicesinc/libiio |