From 65cff70464068a823b3f4a28074000febdce0630 Mon Sep 17 00:00:00 2001 From: Kent Gibson Date: Mon, 28 Sep 2020 08:27:59 +0800 Subject: gpiolib: cdev: support setting debounce 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 Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/gpio/gpiolib.h') diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 39b356160937..b674b5bb980e 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -124,6 +124,10 @@ struct gpio_desc { #ifdef CONFIG_OF_DYNAMIC struct device_node *hog; #endif +#ifdef CONFIG_GPIO_CDEV + /* debounce period in microseconds */ + unsigned int debounce_period_us; +#endif }; int gpiod_request(struct gpio_desc *desc, const char *label); -- cgit v1.2.3