gpiolib: cdev: support setting debounce

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Add support for setting debounce on a line via the GPIO uAPI.
Where debounce is not supported by hardware, a software debounce is
provided.

The implementation of the software debouncer waits for the line to be
stable for the debounce period before determining if a level change,
and a corresponding edge event, has occurred.  This provides maximum
protection against glitches, but also introduces a debounce_period
latency to edge events.

The software debouncer is integrated with the edge detection as it
utilises the line interrupt, and integration is simpler than getting
the two to interwork.  Where software debounce AND edge detection is
required, the debouncer provides both.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

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Kent Gibson 2020-09-28 08:27:59 +08:00 • committed by Bartosz Golaszewski

parent 7b8e00d981

commit 65cff70464

3 changed files with 244 additions and 10 deletions

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247

drivers/gpio/gpiolib-cdev.c

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3

drivers/gpio/gpiolib.c

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4

drivers/gpio/gpiolib.h

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