ADIS16480 driver

지원 장치와 측정 기능

이 드라이버는 SPI 버스에 연결된 Analog Devices IMU를 지원합니다.

각 장치는 3축 자이로스코프와 3축 가속도계를 포함한 완전 관성 시스템입니다. 각 관성 센서는 동적 성능을 최적화하는 신호 조절 회로와 결합됩니다.

공장 보정은 각 센서의 감도, 바이어스, 정렬을 특성화합니다. 그 결과 각 센서는 정확한 측정값을 제공하는 고유한 동적 보상 공식을 갖습니다.

가속도계와 자이로스코프 측정값은 항상 제공됩니다. 장치가 계산한 delta angle과 delta velocity도 드라이버를 통해 읽을 수 있습니다. Delta angle은 샘플 갱신 사이의 각변위를, delta velocity는 샘플 갱신 사이의 선형 속도 변화를 나타냅니다.

온도 데이터는 IMU 내부 온도의 대략적인 값으로, 열 환경의 상대 변화를 감시하는 데 유용합니다. ADIS16480과 ADIS16488은 기압 데이터와 3축 자력계 측정값도 제공합니다.

각 IIO 장치에는 `/sys/bus/iio/devices/iio:deviceX` 폴더가 있으며 X는 IIO 장치 인덱스입니다. 하드웨어 기능에 따른 장치 파일이 이 경로 아래에 생성되고 IIO ABI 규칙을 따릅니다.

.. SPDX-License-Identifier: GPL-2.0

================
ADIS16480 driver
================

This driver supports Analog Device's IMUs on SPI bus.

1. Supported devices
====================

* `ADIS16375 <https://www.analog.com/ADIS16375>`_
* `ADIS16480 <https://www.analog.com/ADIS16480>`_
* `ADIS16485 <https://www.analog.com/ADIS16485>`_
* `ADIS16486 <https://www.analog.com/ADIS16486>`_
* `ADIS16487 <https://www.analog.com/ADIS16487>`_
* `ADIS16488 <https://www.analog.com/ADIS16488>`_
* `ADIS16489 <https://www.analog.com/ADIS16489>`_
* `ADIS16490 <https://www.analog.com/ADIS16490>`_
* `ADIS16495 <https://www.analog.com/ADIS16495>`_
* `ADIS16497 <https://www.analog.com/ADIS16497>`_
* `ADIS16545 <https://www.analog.com/ADIS16545>`_
* `ADIS16547 <https://www.analog.com/ADIS16547>`_

Each supported device is a complete inertial system that includes a triaxial
gyroscope and a triaxial accelerometer. Each inertial sensor in device combines
with signal conditioning that optimizes dynamic performance. The factory
calibration characterizes each sensor for sensitivity, bias, and alignment. As
a result, each sensor has its own dynamic compensation formulas that provide
accurate sensor measurements.

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.

ADIS16480 and ADIS16488 also provide access to barometric pressure data and
triaxial magnetometer measurements.

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 adis16480 related device files, found in the
specific device folder path ``/sys/bus/iio/devices/iio:deviceX``.

자력계·기압계와 가속도 속성

3축 자력계와 기압 센서 속성은 ADIS16480과 ADIS16488에서만 사용할 수 있습니다.

다음 가속도계와 delta velocity 속성은 모든 지원 장치에서 사용할 수 있습니다.

**Available only for ADIS16480 and ADIS16488:**

+------------------------------------------+---------------------------------------------------------+
| 3-Axis Magnetometer related device files | Description                                             |
+------------------------------------------+---------------------------------------------------------+
| in_magn_scale                            | Scale for the magnetometer channels.                    |
+------------------------------------------+---------------------------------------------------------+
| in_magn_x_calibbias                      | Calibration offset for the X-axis magnetometer channel. |
+------------------------------------------+---------------------------------------------------------+
| in_magn_x_filter_low_pass_3db_frequency  | Bandwidth for the X-axis magnetometer channel.          |
+------------------------------------------+---------------------------------------------------------+
| in_magn_x_raw                            | Raw X-axis magnetometer channel value.                  |
+------------------------------------------+---------------------------------------------------------+
| in_magn_y_calibbias                      | Calibration offset for the Y-axis magnetometer channel. |
+------------------------------------------+---------------------------------------------------------+
| in_magn_y_filter_low_pass_3db_frequency  | Bandwidth for the Y-axis magnetometer channel.          |
+------------------------------------------+---------------------------------------------------------+
| in_magn_y_raw                            | Raw Y-axis magnetometer channel value.                  |
+------------------------------------------+---------------------------------------------------------+
| in_magn_z_calibbias                      | Calibration offset for the Z-axis magnetometer channel. |
+------------------------------------------+---------------------------------------------------------+
| in_magn_z_filter_low_pass_3db_frequency  | Bandwidth for the Z-axis magnetometer channel.          |
+------------------------------------------+---------------------------------------------------------+
| in_magn_z_raw                            | Raw Z-axis magnetometer channel value.                  |
+------------------------------------------+---------------------------------------------------------+

+------------------------------------------+-----------------------------------------------------+
| Barometric pressure sensor related files | Description                                         |
+------------------------------------------+-----------------------------------------------------+
| in_pressure0_calibbias                   | Calibration offset for barometric pressure channel. |
+------------------------------------------+-----------------------------------------------------+
| in_pressure0_raw                         | Raw barometric pressure channel value.              |
+------------------------------------------+-----------------------------------------------------+
| in_pressure0_scale                       | Scale for the barometric pressure sensor channel.   |
+------------------------------------------+-----------------------------------------------------+

**Available for all supported devices:**

+-------------------------------------------+----------------------------------------------------------+
| 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_calibscale                     | Calibration scale for the X-axis accelerometer channel.  |
+-------------------------------------------+----------------------------------------------------------+
| in_accel_x_filter_low_pass_3db_frequency  | Bandwidth 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_calibscale                     | Calibration scale for the Y-axis accelerometer channel.  |
+-------------------------------------------+----------------------------------------------------------+
| in_accel_y_filter_low_pass_3db_frequency  | Bandwidth 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_calibscale                     | Calibration scale for the Z-axis accelerometer channel.  |
+-------------------------------------------+----------------------------------------------------------+
| in_accel_z_filter_low_pass_3db_frequency  | Bandwidth 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.                 |
+-------------------------------------------+----------------------------------------------------------+

자이로스코프·온도와 debugfs

ADIS16480 관련 디버그 파일은 `/sys/kernel/debug/iio/iio:deviceX`에 있습니다.

+--------------------------------------------+------------------------------------------------------+
| 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_calibscale                    | Calibration scale for the X-axis gyroscope channel.  |
+--------------------------------------------+------------------------------------------------------+
| in_anglvel_x_filter_low_pass_3db_frequency | Bandwidth 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_calibscale                    | Calibration scale for the Y-axis gyroscope channel.  |
+--------------------------------------------+------------------------------------------------------+
| in_anglvel_y_filter_low_pass_3db_frequency | Bandwidth 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_calibscale                    | Calibration scale for the Z-axis gyroscope channel.  |
+--------------------------------------------+------------------------------------------------------+
| in_anglvel_z_filter_low_pass_3db_frequency | Bandwidth 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_offset                  | Offset for the temperature sensor channel.|
+----------------------------------+-------------------------------------------+
| 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.                         |
+-------------------------------+---------------------------------------------------------+

The following table shows the adis16480 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. 16480, 16488, 16545, 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. |
+----------------------+-------------------------------------------------------------------------+

처리값 단위와 설정 예제

채널의 `_raw` 속성은 장치가 보고한 원시 값을 반환합니다. 처리값은 다음 공식으로 계산합니다.

processed value = (_raw + _offset) * _scale

`_offset`과 `_scale`은 장치 속성이며 `_offset`이 없으면 0으로 간주합니다.

장치 이름을 읽는 예제 결과는 `adis16545-1`입니다.

root:/sys/bus/iio/devices/iio:device0> cat name
adis16545-1

가속도 예제는 X·Y·Z축 원시 값 1376728, 4487621, 262773792와 배율 0.000000037을 읽습니다. 계산 결과는 각각 0.050938936 m/s², 0.166041977 m/s², 9.722630304 m/s²입니다.

root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw
1376728
root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw
4487621
root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw
262773792
root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale
0.000000037

자이로스코프 예제는 X·Y·Z축 원시 값 −1041702, −273013, 2745116과 배율 0.000000001을 읽습니다. 결과는 −0.001041702 rad/s, −0.000273013 rad/s, 0.002745116 rad/s입니다.

root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw
-1041702
root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw
-273013
root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw
2745116
root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale
0.000000001

가속도계 X축 `calibbias`는 0에서 5000으로, 자이로스코프 Y축 `calibbias`는 0에서 −5000으로 변경하는 예제를 제공합니다.

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
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

샘플링 주파수는 처음 4250.000000입니다. `sampling_frequency`에 1000을 쓰면 장치가 지원하는 실제 값 1062.500000으로 설정됩니다.

root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency
4250.000000
root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency
1062.500000

가속도계 X축 저역 통과 3 dB 대역폭은 처음 0이며, `in_accel_x_filter_low_pass_3db_frequency`에 300을 쓰면 300으로 설정됩니다.

root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_filter_low_pass_3db_frequency
0
root:/sys/bus/iio/devices/iio:device0> echo 300 > in_accel_x_filter_low_pass_3db_frequency
root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_filter_low_pass_3db_frequency
300

Debugfs 예제는 일련번호 `0x000c`, 제품 ID `16545`, flash write 횟수 `88`, 펌웨어 리비전 `1.4`, 펌웨어 날짜 `09-23-2023`을 읽습니다.

root:/sys/kernel/debug/iio/iio:device0> cat serial_number
0x000c
root:/sys/kernel/debug/iio/iio:device0> cat product_id
16545
root:/sys/kernel/debug/iio/iio:device0> cat flash_count
88
root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision
1.4
root:/sys/kernel/debug/iio/iio:device0> cat firmware_date
09-23-2023

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 adis16480 driver offers data for 7 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      |
+--------------------------------------+---------------------------+
| Magnetic field along X, Y and Z axis | Gauss                     |
+--------------------------------------+---------------------------+
| Barometric pressure                  | kilo Pascal               |
+--------------------------------------+---------------------------+

Usage examples
--------------

Show device name:

.. code-block:: bash

        root:/sys/bus/iio/devices/iio:device0> cat name
        adis16545-1

Show accelerometer channels value:

.. code-block:: bash

        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw
        1376728
        root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw
        4487621
        root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw
        262773792
        root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale
        0.000000037

- X-axis acceleration = in_accel_x_raw * in_accel_scale = 0.050938936 m/s^2
- Y-axis acceleration = in_accel_y_raw * in_accel_scale = 0.166041977 m/s^2
- Z-axis acceleration = in_accel_z_raw * in_accel_scale = 9.722630304 m/s^2

Show gyroscope channels value:

.. code-block:: bash

        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw
        -1041702
        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw
        -273013
        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw
        2745116
        root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale
        0.000000001

- X-axis angular velocity = in_anglvel_x_raw * in_anglvel_scale = −0.001041702 rad/s
- Y-axis angular velocity = in_anglvel_y_raw * in_anglvel_scale = −0.000273013 rad/s
- Z-axis angular velocity = in_anglvel_z_raw * in_anglvel_scale = 0.002745116 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
        4250.000000

        root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency
        1062.500000

Set bandwidth for accelerometer channels:

.. code-block:: bash

        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_filter_low_pass_3db_frequency
        0

        root:/sys/bus/iio/devices/iio:device0> echo 300 > in_accel_x_filter_low_pass_3db_frequency
        root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_filter_low_pass_3db_frequency
        300

Show serial number:

.. code-block:: bash

        root:/sys/kernel/debug/iio/iio:device0> cat serial_number
        0x000c

Show product id:

.. code-block:: bash

        root:/sys/kernel/debug/iio/iio:device0> cat product_id
        16545

Show flash count:

.. code-block:: bash

        root:/sys/kernel/debug/iio/iio:device0> cat flash_count
        88

Show firmware revision:

.. code-block:: bash

        root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision
        1.4

Show firmware date:

.. code-block:: bash

        root:/sys/kernel/debug/iio/iio:device0> cat firmware_date
        09-23-2023

IIO 버퍼와 인터페이스 도구

이 드라이버는 IIO 버퍼를 지원합니다. 모든 장치는 버퍼를 통해 원시 가속도, 자이로스코프, 온도 측정값을 읽을 수 있습니다.

ADIS16545와 ADIS16547은 delta velocity, delta angle, 온도 측정값도 버퍼로 읽을 수 있습니다.

버퍼에서 가속도 또는 자이로스코프를 읽을 때 delta 값은 사용할 수 없고 그 반대도 마찬가지입니다. 장치가 한 번에 일반 가속도·자이로스코프 burst 또는 delta velocity·delta angle burst 중 하나만 읽도록 허용하며 두 burst 선택 모드 전환에 시간이 많이 들기 때문입니다.

버퍼 사용 전에 `trigger/current_trigger`가 비어 있으면 장치 트리거 `adis16545-1-dev0`을 설정합니다.

root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
root:/sys/bus/iio/devices/iio:device0> echo adis16545-1-dev0 > trigger/current_trigger
root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
adis16545-1-dev0

X·Y·Z축 delta velocity와 온도 scan element를 활성화하고, 버퍼 길이를 10으로 설정한 뒤 버퍼를 켭니다.

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
root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length
root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable

버퍼 데이터는 `hexdump -C /dev/iio\:device0`로 확인합니다. 원문의 16진수 출력은 각 스캔 레코드의 원시 바이트 배열을 그대로 보여 줍니다.

root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0

버퍼 데이터 구조는 `Documentation/iio/iio_devbuf.rst`를 참고합니다. 사용 가능한 IIO 인터페이스 도구는 `Documentation/iio/iio_tools.rst`에 설명되어 있습니다.

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:

- ADIS16545
- ADIS16547

However, when retrieving acceleration or gyroscope data using buffers, delta
readings will not be available and vice versa. This is because the device only
allows to read either acceleration and gyroscope data or delta velocity and
delta angle data at a time and switching between these two burst data selection
modes is time consuming.

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 adis16545-1-dev0 > trigger/current_trigger
        root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
        adis16545-1-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::

  root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0
  ...
  00006aa0  09 62 00 00 ff ff fc a4  00 00 01 69 00 03 3c 08  |.b.........i..<.|
  00006ab0  09 61 00 00 00 00 02 96  00 00 02 8f 00 03 37 50  |.a............7P|
  00006ac0  09 61 00 00 00 00 12 3d  00 00 0b 89 00 03 2c 0b  |.a.....=......,.|
  00006ad0  09 61 00 00 00 00 1e dc  00 00 16 dd 00 03 25 bf  |.a............%.|
  00006ae0  09 61 00 00 00 00 1e e3  00 00 1b bf 00 03 27 0b  |.a............'.|
  00006af0  09 61 00 00 00 00 15 50  00 00 19 44 00 03 30 fd  |.a.....P...D..0.|
  00006b00  09 61 00 00 00 00 09 0e  00 00 14 41 00 03 3d 7f  |.a.........A..=.|
  00006b10  09 61 00 00 ff ff ff f0  00 00 0e bc 00 03 48 d0  |.a............H.|
  00006b20  09 63 00 00 00 00 00 9f  00 00 0f 37 00 03 4c fe  |.c.........7..L.|
  00006b30  09 64 00 00 00 00 0b f6  00 00 18 92 00 03 43 22  |.d............C"|
  00006b40  09 64 00 00 00 00 18 df  00 00 22 33 00 03 33 ab  |.d........"3..3.|
  00006b50  09 63 00 00 00 00 1e 81  00 00 26 be 00 03 29 60  |.c........&...)`|
  00006b60  09 63 00 00 00 00 1b 13  00 00 22 2f 00 03 23 91  |.c........"/..#.|
  ...

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.