This series introduces a driver for the QPNP haptics hardware block
found in Qualcomm PMICs. QPNP haptics support LRA (Linear Resonant
Actuator) style haptics, as well as ERM (Eccentric Rotating Mass).
It also supports several modes of driving the haptics, e.g. by loading
the pattern to play into an internal buffer, or using PWM.
More information about the hardware can be found here:
https://gitlab.com/sdm845-mainline/linux/-/wikis/PMI8998-QPNP-Haptics
This driver has been written based on downstream sources as no public
documentation is available. It includes initial support for LRA haptics
in buffer mode, this combination seems to be the most common and will
enable haptics on the OnePlus 6 and 6T, PocoPhone F1, OnePlus 5 and
several other Qualcomm devices with mainline kernel support.
The driver is implemented using the ff-memless (forcefeedback) input
framework and makes an attempt to control the strength of vibration relative
to the magnitude set from userspace.
~ Caleb
