[PATCH 0/8] counter: ti-eqep: implement features for speed measurement

From: David Lechner
Date: Sat Oct 16 2021 - 21:56:43 EST


Now that the counter subsystem has a new chrdev for events, we can use this to
add new features to the TI eQEP driver to be able to do accurate speed
measurement.

This adds two new device-level components, a Unit Timer and an Edge Capture
Unit. I don't have much knowledge about other available counter hardware, so
I don't know if it makes sense to try to make these more generic, e.g.
counterX/timerY/* and counterX/captureY/*. For now, they are just flat
(counterX/unit_timer_* and counterX/edge_capture_unit_*) and assume there is
only one instance per counter device.

This has been tested on a BeagleBone Blue with LEGO MINDSTORMS motors.

David Lechner (8):
counter/ti-eqep: implement over/underflow events
counter/ti-eqep: add support for direction
counter/ti-eqep: add support for unit timer
docs: counter: add unit timer sysfs attributes
counter/ti-eqep: add support for latched position
docs: counter: add latch_mode and latched_count sysfs attributes
counter/ti-eqep: add support for edge capture unit
docs: counter: add edge_capture_unit_* attributes

Documentation/ABI/testing/sysfs-bus-counter | 100 +++-
drivers/counter/ti-eqep.c | 482 +++++++++++++++++++-
include/uapi/linux/counter.h | 4 +
3 files changed, 575 insertions(+), 11 deletions(-)

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2.25.1