On Wed, 27 Apr 2022 15:42:49 +0200 Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote: > On Tue, Apr 26, 2022 at 3:11 PM Andrea Merello <andrea.merello@xxxxxxxxx> wrote: > > > > From: Andrea Merello <andrea.merello@xxxxxx> > > > > This series (tries to) add support for Bosch BNO055 IMU to Linux IIO > > subsystem. It is made up several patches: > > > > 1/14 to 6/14: add some IIO modifiers, and their documentation, to the IIO > > core layer, in order to being able to expose the linear > > acceleration and Euler angles among standard attributes. > > Also update the IIO event monitor tool > > > > 7/14: fix binary attributes didn't work with IIO > > > > 8/14 to 11/14: add the core IIO BNO055 driver and documentation for sysfs > > attributes and DT bindings > > > > 12/14: adds serdev BNO055 driver to actually use the IMU via serial line > > > > 13/14: adds I2C BNO055 driver to actually use the IMU via I2C wiring > > > > 14/14: add a documentation file that describe the bno055 driver and > > specifically the calibration > > FWIW, > Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> > for non-commented patches (12 out of 14 AFAICS). > FWIW I'm fine with the series once you've tidied up the stuff Andy picked up on. Thanks Andy for the detailed reviewing btw. Jonathan > > Differences wrt v4: > > - be more tolerant wrt unrecognized chip IDs > > - rename 'serial_number' attribute in 'serialnumber' > > - fix missing NULL variable initialization > > - use sign_extend32() instead of s16 casting where appropriate > > - fix quaternion unit > > - minor stuff (e.g. comments..) > > - reduce (slightly) locking in serdev driver > > - rework tracepoint support (e.g. remove dedicated config option) > > > > Differences wrt other BNO055 drivers: > > > > Previously at least another driver for the very same chip has been posted > > to the Linux ML [0], but it has been never merged, and it seems no one > > cared of it since quite a long time. > > > > This driver differs from the above driver on the following aspects: > > > > - This driver supports also serial access (to be reliable, reset pin is > > required to be wired) > > > > - The above driver tried to support all IMU HW modes by allowing to > > choose one in the DT, and adapting IIO attributes accordingly. This > > driver does not rely on DT for this, instead settings are done via > > sysfs attributes. All IIO attributes are always exposed; more on this > > later on. This driver however supports only a subset of the > > HW-supported modes. > > > > - This driver has some support for managing the IMU calibration > > > > Supported operation modes: > > > > - AMG (accelerometer, magnetometer and gyroscope) mode, which provides > > raw (uncalibrated) measurements from the said sensors, and allows for > > setting some parameters about them (e.g. filter cut-off frequency, max > > sensor ranges, etc). > > > > - Fusion mode, which still provides AMG measures, while it also provides > > other data calculated by the IMU (e.g. rotation angles, linear > > acceleration, etc). In this mode user has no freedom to set any sensor > > parameter, since the HW locks them. Autocalibration and correction is > > performed by the IMU. > > > > IIO attributes exposing sensors parameters are always present, but in > > fusion modes the available values are constrained to just the one used by > > the HW. This is reflected in the '*_available' IIO attributes. > > > > Trying to set a not-supported value always falls back to the closest > > supported one, which in this case is just the one in use by the HW. > > > > IIO attributes for unavailable measurements (e.g. Euler angles in AMG > > mode) can't be read (return -EBUSY, or refuse to enable buffer). > > > > IMU calibration: > > > > The IMU supports for two sets of calibration parameters: > > > > - SIC matrix. user-provided; this driver doesn't currently support it > > > > - Offset and radius parameters. The IMU automatically finds out them when > > it is running in fusion mode; supported by this driver. > > > > The driver provides access to autocalibration flags (i.e. you can known > > if the IMU has successfully autocalibrated) and to 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 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 changes on each device). > > > > In AMG 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 > > and read as zero. > > > > > > Access protocols and serdev module: > > > > The serial protocol is quite simple, but there are tricks to make it > > really works. Those tricks and workarounds are documented in the driver > > source file. > > > > The core BNO055 driver tries to group readings in burst when appropriate, > > in order to optimize triggered buffer operation. The threshold for > > splitting a burst (i.e. max number of unused bytes in the middle of a > > burst that will be throw away) is provided to the core driver by the > > lowlevel access driver (either serdev or I2C) at probe time. > > > > [0] https://www.spinics.net/lists/linux-iio/msg25508.html > > > > Andrea Merello (14): > > iio: add modifiers for linear acceleration > > iio: document linear acceleration modifiers > > iio: event_monitor: add linear acceleration modifiers > > iio: add modifers for pitch, yaw, roll > > iio: document pitch, yaw, roll modifiers > > iio: event_monitor: add pitch, yaw and roll modifiers > > iio: add support for binary attributes > > iio: imu: add Bosch Sensortec BNO055 core driver > > iio: document bno055 private sysfs attributes > > iio: document "serialnumber" sysfs attribute > > dt-bindings: iio/imu: Add Bosch BNO055 > > iio: imu: add BNO055 serdev driver > > iio: imu: add BNO055 I2C driver > > docs: iio: add documentation for BNO055 driver > > > > Documentation/ABI/testing/sysfs-bus-iio | 25 + > > .../ABI/testing/sysfs-bus-iio-bno055 | 81 + > > .../bindings/iio/imu/bosch,bno055.yaml | 59 + > > Documentation/iio/bno055.rst | 50 + > > Documentation/iio/index.rst | 2 + > > drivers/iio/imu/Kconfig | 1 + > > drivers/iio/imu/Makefile | 1 + > > drivers/iio/imu/bno055/Kconfig | 25 + > > drivers/iio/imu/bno055/Makefile | 10 + > > drivers/iio/imu/bno055/bno055.c | 1710 +++++++++++++++++ > > drivers/iio/imu/bno055/bno055.h | 12 + > > drivers/iio/imu/bno055/bno055_i2c.c | 57 + > > drivers/iio/imu/bno055/bno055_ser_core.c | 560 ++++++ > > drivers/iio/imu/bno055/bno055_ser_trace.h | 104 + > > drivers/iio/industrialio-core.c | 10 +- > > include/uapi/linux/iio/types.h | 7 +- > > tools/iio/iio_event_monitor.c | 6 + > > 17 files changed, 2718 insertions(+), 2 deletions(-) > > create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-bno055 > > create mode 100644 Documentation/devicetree/bindings/iio/imu/bosch,bno055.yaml > > create mode 100644 Documentation/iio/bno055.rst > > create mode 100644 drivers/iio/imu/bno055/Kconfig > > create mode 100644 drivers/iio/imu/bno055/Makefile > > create mode 100644 drivers/iio/imu/bno055/bno055.c > > create mode 100644 drivers/iio/imu/bno055/bno055.h > > create mode 100644 drivers/iio/imu/bno055/bno055_i2c.c > > create mode 100644 drivers/iio/imu/bno055/bno055_ser_core.c > > create mode 100644 drivers/iio/imu/bno055/bno055_ser_trace.h > > > > -- > > 2.17.1 > > >
