iio: dummy: iio_simple_dummy_events: Demote file header and supply descriptions for val2 params

File headers are not good candidates for kerneldoc.

Fixes the following W=1 kernel build warning(s):

drivers/iio/dummy/iio_simple_dummy_events.c:21: warning: Incorrect use of kernel-doc format: * iio_simple_dummy_read_event_config() - is event enabled?
drivers/iio/dummy/iio_simple_dummy_events.c:34: warning: Function parameter or member 'indio_dev' not described in 'iio_simple_dummy_read_event_config'
drivers/iio/dummy/iio_simple_dummy_events.c:34: warning: Function parameter or member 'chan' not described in 'iio_simple_dummy_read_event_config'
drivers/iio/dummy/iio_simple_dummy_events.c:34: warning: Function parameter or member 'type' not described in 'iio_simple_dummy_read_event_config'
drivers/iio/dummy/iio_simple_dummy_events.c:34: warning: Function parameter or member 'dir' not described in 'iio_simple_dummy_read_event_config'
drivers/iio/dummy/iio_simple_dummy_events.c:123: warning: Function parameter or member 'val2' not described in 'iio_simple_dummy_read_event_value'
drivers/iio/dummy/iio_simple_dummy_events.c:146: warning: Function parameter or member 'val2' not described in 'iio_simple_dummy_write_event_value'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: dummy: events: Add missing break

Add missing break in iio_simple_dummy_write_event_config() for the voltage
threshold event enable attribute. Without this writing to the
in_voltage0_thresh_rising_en always returns -EINVAL even though the change
was correctly applied.

Fixes: 3e34e650db197 ("iio: dummy: Demonstrate the usage of new channel types")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:core: timestamping clock selection support

Adds a new per-device sysfs attribute "current_timestamp_clock" to allow
userspace to select a particular POSIX clock for buffered samples and
events timestamping.

Following clocks, as listed in clock_gettime(2), are supported:
CLOCK_REALTIME, CLOCK_MONOTONIC, CLOCK_MONOTONIC_RAW,
CLOCK_REALTIME_COARSE, CLOCK_MONOTONIC_COARSE, CLOCK_BOOTTIME and
CLOCK_TAI.

Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
Acked-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Move IIO Dummy Driver out of staging

This patch moves the reference IIO dummy driver from drivers/staging/iio
into a separate folder, drivers/iio/dummy and adds the proper Kconfig
and Makefile for it.

A new config menu entry called IIO dummy driver has also been added
in the Industrial I/O support menu, corresponding to this driver.

Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>