iio-sensor-proxy expects the accelerometer oriented as follows:
positive x - to the right, positive y - up (opposite to gravity).
The hardware in the Asus TP300LJ-DW049H is however oriented
differently:
positive x - down, positive y - to the left
This commit adds a ACCEL_MOUNT_MATRIX quirk for this
particular laptop model.
This patch adds quirks for the two laptops I could test on
(8540w and 8560w). The accelerometer is configured in the
kernel to report values according to the base of the laptop.
We want the values according to the screen instead.
It is likely (but untested) to match all HP laptops with the
lis3lv02d accelerometer on this list:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/platform/x86/hp_accel.c#n207
This commit adds a rules file to extract the properties from hwdb
to set on i2c IIO devices. This is used to set the ACCEL_MOUNT_MATRIX
property on IIO devices, to be consumed by iio-sensor-proxy or
equivalent daemon.
The hwdb file contains documentation on how to write quirks. Note
however that mount information is usually exported in:
- the device-tree for ARM devices
- the ACPI DSDT for Intel-compatible devices
but currently not extracted by the kernel.
Also note that some devices have the framebuffer rotation that changes
between the bootloader and the main system, which might mean that the
accelerometer is then wrongly oriented. This is a missing feature in the
i915 kernel driver: https://bugs.freedesktop.org/show_bug.cgi?id=94894
which needs to be fixed, and won't require quirks.
