diff options
| author | Andrea Merello <andrea.merello@iit.it> | 2022-09-07 15:22:05 +0200 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2022-09-21 18:42:56 +0100 |
| commit | 130476acfdc1663bc402faa3f2faab5a910f696a (patch) | |
| tree | 5c39c3e0e3a4cf41893e9d4054017f386bf8bb85 /Documentation/iio | |
| parent | 50fe984f376abb4a00f80e13f51465ef09c2bde7 (diff) | |
docs: iio: add documentation for BNO055 driver
The bno055 driver is rather complex and have some oddities and not-obvious
things that worth to document (e.g. calibration files).
This patch also contains this [0] fix squashed in.
[0] https://lore.kernel.org/lkml/20220704034041.15448-1-bagasdotme@gmail.com/
Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220907132205.28021-15-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'Documentation/iio')
| -rw-r--r-- | Documentation/iio/bno055.rst | 51 | ||||
| -rw-r--r-- | Documentation/iio/index.rst | 2 |
2 files changed, 53 insertions, 0 deletions
diff --git a/Documentation/iio/bno055.rst b/Documentation/iio/bno055.rst new file mode 100644 index 000000000000..9a489a79d8f5 --- /dev/null +++ b/Documentation/iio/bno055.rst @@ -0,0 +1,51 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================== +BNO055 driver +============================== + +1. Overview +=========== + +This driver supports Bosch BNO055 IMUs (on both serial and I2C busses). + +Accelerometer, magnetometer and gyroscope measures are always provided. +When "fusion_enable" sysfs attribute is set to 1, orientation (both Euler +angles and quaternion), linear velocity and gravity vector are also +provided, but some sensor settings (e.g. low pass filtering and range) +became locked (the IMU firmware controls them). + +This driver supports also IIO buffers. + +2. Calibration +============== + +The IMU continuously performs an autocalibration procedure if (and only if) +operating in fusion mode. The magnetometer autocalibration can however be +disabled writing 0 in the sysfs in_magn_calibration_fast_enable attribute. + +The driver provides access to autocalibration flags (i.e. you can known if +the IMU has successfully autocalibrated) and to the calibration data blob. + +The user can save this blob in a firmware file (i.e. in /lib/firmware) that +the driver looks for at probe time. If found, then the IMU is initialized +with this calibration data. This saves the user from performing the +calibration procedure every time (which consist of moving the IMU in +various way). + +The driver looks for calibration data file using two different names: first +a file whose name is suffixed with the IMU unique ID (exposed in sysfs as +serial_number) is searched for; this is useful when there is more than one +IMU instance. If this file is not found, then a "generic" calibration file +is searched for (which can be used when only one IMU is present, without +struggling with fancy names, that change on each device). + +Valid calibration file names would be e.g. + bno055-caldata-0e7c26a33541515120204a35342b04ff.dat + bno055-caldata.dat + +In non-fusion mode the IIO 'offset' attributes provide access to the +offsets from calibration data (if any), so that the user can apply them to +the accel, angvel and magn IIO attributes. In fusion mode they are not +needed (the IMU firmware internally applies those corrections) and they +read as zero. diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst index 58b7a4ebac51..1b7292c58cd0 100644 --- a/Documentation/iio/index.rst +++ b/Documentation/iio/index.rst @@ -10,3 +10,5 @@ Industrial I/O iio_configfs ep93xx_adc + + bno055 |