As we intend to eventually get board related parameters from a configuration
file, this commit makes the GPIO numbers for data-ready pins be instance
variables instead of from C constant macros.
Another advantage of using instance variables in this context is the
possibility of using more than one LSM9DS0.
If the data-ready polling is done entirely on GPIO pins, it isn't necessary to
hold the semaphore before we now we have data to consume. In that case, only
take the SPI semaphore if there's new data available.
On the other hand, if at least one SPI transaction is done in order to check
for new data, then it makes sense to take the semaphore beforehand.
This commit makes accel and gyro initialization routines use bitfield macros
instead of hardcoding the literal value when wrinting on registers. That is
less prone to typos and a lot of times self-explanatory. Also, due to the
latter, the long comments explaining each register field were removed (any
detail can be checked on the datasheet).
This adds the backend driver for LSM9DS0. This implementation is based on the
legacy driver coded by Víctor Mayoral Vilches (under folder LSM9DS0) and makes
some necessary adaptations and fixes in order to work properly. The legacy
driver folder was removed.
The calibration on LSM9DS0 was giving offsets between 4.0 and 4.2 on x-axis and
around 3.6 on y-axis. It turned out that those offsets were actually right.
The maximum absolute values of calibration offset should be a sensor
characteristic rather than a constant value for all sensors.
The constant value previously used (3.5 m/s/s for all axes) is set here as a
default maximum absolute calibration offset for every instance to keep it
working.
The previous implementation made some boards apply two rotations to suit
their default orientation. That was happening because there was an
unconditional rotation being done (commented as "rotate for bbone
default").
This commit makes that unconditional rotation as a default rotation
instead and adjusts the former additional rotations to be single
rotations.
As the datasheet says: "To prevent switching into I2C mode when using
SPI, the I2C interface should be disabled by setting the I2C_IF_DIS
configuration bit."
We also reset the sensor like PX4Firmware does for initializing the
MPU6000. See: ee1d8cd770/src/drivers/mpu6000/mpu6000.cpp (L695)
