iio: hrtimer-trigger: Fix potential integer overflow in iio_hrtimer_store_sampling_frequency

Add suffix ULL to constant 1000 in order to avoid a potential integer
overflow and give the compiler complete information about the proper
arithmetic to use. Notice that this constant is being used in a context
that expects an expression of type unsigned long long, but it's
currently evaluated using 32-bit arithmetic.

Addresses-Coverity-ID: 1503062 ("Unintentional integer overflow")
Fixes: dafcf4ed8392 ("iio: hrtimer: Allow sub Hz granularity")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20210329205817.GA188755@embeddedor
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: set default trig->dev.parent

When allocated with [devm_]iio_trigger_alloc(), set trig device parent to
the device the trigger is allocated for by default.

It can always be reassigned in the probe routine.

Change iio_trigger_alloc() API to add the device pointer to be coherent
with devm_iio_trigger_alloc, using similar interface to
iio_device_alloc().

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210309193620.2176163-2-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Remove kernel-doc keyword in file header comment

Remove kernel-doc keyword from function header comment.
It fixes issues spotted by scripts/kernel-doc like:
drivers/iio/<driver>.c:3: info: Scanning doc for function <component name>
drivers/iio/<driver>.c:X: warning: expecting prototype for <component name>.
Prototype was for <function>() instead

To reproduce the errors:
scripts/kernel-doc -v -none $(find drivers/iio/ -name \*.c \
-exec head -2 {} \+ | grep -B2 -e '\*\*' | grep '==' | cut -d ' ' -f 2)

After, confirm these errors are gone with:
scripts/kernel-doc -v -none $(git show --name-only | grep -e "^driver")

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Link: https://lore.kernel.org/r/20210309234314.2208256-1-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: hrtimer: Allow sub Hz granularity

Allow setting frequency below 1Hz or sub 1Hz precision.
Useful for slow sensors like ALS.

Test frequency is set properly:
modprobe iio-trig-hrtimer && \
mkdir /sys/kernel/config/iio/triggers/hrtimer/t1 && \
cd /sys/bus/iio/devices/triggerX ;
for i in 1 .1 .01 .001 ; do
echo $i > sampling_frequency
cat sampling_frequency
done

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210226014733.2108544-1-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: hrtimer-trigger: Mark hrtimer to expire in hard interrupt context

On PREEMPT_RT enabled kernels unmarked hrtimers are moved into soft
interrupt expiry mode by default.

The IIO hrtimer-trigger needs to run in hard interrupt context since it
will end up calling generic_handle_irq() which has the requirement to run
in hard interrupt context.

Explicitly specify that the timer needs to run in hard interrupt context by
using the HRTIMER_MODE_REL_HARD flag.

Fixes: f5c2f0215e36 ("hrtimer: Move unmarked hrtimers to soft interrupt expiry on RT")
Reported-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20201117103751.16131-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Fix misspellings of "Analog Devices"

According to https://www.analog.com/, the company name is spelled
"Analog Devices".

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
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: make function argument and some structures const

Make the argument of the functions iio_sw{d/t}_group_init_type_name const
as they are only passed to the function config_group_init_type_name having
the argument as const.

Make the config_item_type structures const as they are either passed to
the functions having the argument as const or they are
stored in the const "ci_type" field of a config_item structure.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

iio:triggers: drop assign iio_info.driver_module and iio_trigger_ops.owner

The equivalent of both of these are now done via macro magic when
the relevant register calls are made. The actual structure
elements will shortly go away.

Note that stm32-timer-trigger has expanded rather beyond triggers
(to include encoder input counting for example) and hence has an
iio_info structure.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

ktime: Cleanup ktime_set() usage

ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

iio: trigger: Introduce IIO hrtimer based trigger

This patch registers a new IIO software trigger interrupt source
based on high resolution timers.

Notice that if configfs is enabled we create sampling_frequency
attribute allowing users to change hrtimer period (1/sampling_frequency).

The IIO hrtimer trigger has a long history, this patch is based on
an older version from Marten and Lars-Peter.

Signed-off-by: Marten Svanfeldt <marten@intuitiveaerial.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>