iio: core : events ABI for specifying period

The iio sysfs ABI defines a way to specify period for roc and thresholds.
What:		/sys/.../events/in_accel_x_thresh_rising_period
What:		/sys/.../events/in_accel_x_thresh_falling_period
what:		/sys/.../events/in_accel_x_roc_rising_period
What:		/sys/.../events/in_accel_x_roc_falling_period

But there is no way to add period with the current event info enum.

Added IIO_EV_INFO_PERIOD and corresponding string.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/industrialio-event.c

@@ -209,6 +209,7 @@ static const char * const iio_ev_info_text[] = {
 	[IIO_EV_INFO_ENABLE] = "en",
 	[IIO_EV_INFO_VALUE] = "value",
 	[IIO_EV_INFO_HYSTERESIS] = "hysteresis",
+	[IIO_EV_INFO_PERIOD] = "period",
 };
 
 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)

include/linux/iio/types.h

@@ -70,6 +70,7 @@ enum iio_event_info {
 	IIO_EV_INFO_ENABLE,
 	IIO_EV_INFO_VALUE,
 	IIO_EV_INFO_HYSTERESIS,
+	IIO_EV_INFO_PERIOD,
 };
 
 enum iio_event_direction {