iio: Rename iio_trigger_poll_chained and add kernel-doc

Rename the function to iio_trigger_poll_nested. Add kernel-doc with
a note on the context where the function is expected to be called.

Signed-off-by: Mehdi Djait <mehdi.djait.k@gmail.com>
Link: https://lore.kernel.org/r/841b533cba28ca25a8e87280c44e45979166e8e2.1677761379.git.mehdi.djait.k@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221_buffer: explicitly add proper header files

Do not trust the fact that iio.h includes of.h which in turn includes
all the headers we are relying on.

The ultimate goal is to actually drop of.h from iio.h.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220610084545.547700-16-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:humidity:hts221: rearrange iio trigger get and register

IIO trigger interface function iio_trigger_get() should be called after
iio_trigger_register() (or its devm analogue) strictly, because of
iio_trigger_get() acquires module refcnt based on the trigger->owner
pointer, which is initialized inside iio_trigger_register() to
THIS_MODULE.
If this call order is wrong, the next iio_trigger_put() (from sysfs
callback or "delete module" path) will dereference "default" module
refcnt, which is incorrect behaviour.

Fixes: e4a70e3e7d84 ("iio: humidity: add support to hts221 rh/temp combo device")
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220524181150.9240-6-ddrokosov@sberdevices.ru
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: fix devm_iio_trigger_alloc with parent.cocci

Use cocci semantic patch:
@@
expression trigger, P;
@@
trigger = devm_iio_trigger_alloc(P, ...);
...
- trigger->dev.parent = P;

To remove trigger->dev.parent, since it is set by default.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210309193620.2176163-3-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:humidity:hts221 Fix alignment and data leak issues

One of a class of bugs pointed out by Lars in a recent review.
iio_push_to_buffers_with_timestamp assumes the buffer used is aligned
to the size of the timestamp (8 bytes). This is not guaranteed in
this driver which uses an array of smaller elements on the stack.
As Lars also noted this anti pattern can involve a leak of data to
userspace and that indeed can happen here. We close both issues by
moving to a suitable structure in the iio_priv() data.
This data is allocated with kzalloc so no data can leak
apart from previous readings.

Explicit alignment of ts needed to ensure consistent padding
on all architectures (particularly x86_32 with it's 4 byte alignment
of s64)

Fixes: e4a70e3e7d84 ("iio: humidity: add support to hts221 rh/temp combo device")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: <Stable@vger.kernel.org>

iio: Move attach/detach of the poll func to the core

All devices using a triggered buffer need to attach and detach the trigger
to the device in order to properly work. Instead of doing this in each and
every driver by hand move this into the core.

At this point in time, all drivers should have been resolved to
attach/detach the poll-function in the same order.

This patch removes all explicit calls of iio_triggered_buffer_postenable()
& iio_triggered_buffer_predisable() in all drivers, since the core handles
now the pollfunc attach/detach.

The more peculiar change is for the 'at91-sama5d2_adc' driver, since it's
not immediately obvious that removing the hooks doesn't break anything.
Eugen was able to test on at91-sama5d2-adc driver, sama5d2-xplained board.
All seems to be fine.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Tested-by: Eugen Hristev <eugen.hristev@microchip.com> #for at91-sama5d2-adc
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221: remove usage of iio_priv_to_dev()

We may want to get rid of the iio_priv_to_dev() helper. That's a bit
uncertain at this point. The reason is that we will hide some of the
members of the iio_dev structure (to prevent drivers from accessing them
directly), and that will also mean hiding the implementation of the
iio_priv_to_dev() helper inside the IIO core.

Hiding the implementation of iio_priv_to_dev() implies that some fast-paths
may not be fast anymore, so a general idea is to try to get rid of the
iio_priv_to_dev() altogether.

For this driver, removing the iio_priv_to_dev() helper means passing the
iio_dev object on hts221_allocate_buffers() & hts221_allocate_trigger().

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221: Make use of device properties

Device property API allows to gather device resources from different sources,
such as ACPI. Convert the drivers to unleash the power of device property API.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221: Use dev_get_platdata() to get platform_data

Use dev_get_platdata() to get the platform_data instead of
referencing it directly.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 177

Based on 1 normalized pattern(s):

licensed under the gpl 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 135 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.071193225@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: humidity: hts221: add regmap API support

Introduce regmap API support to access to i2c/spi bus instead of
using a custom support.
Remove lock mutex since concurrency is already managed by regmap API

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221: remove trailing whitespace from a comment

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:humidity: 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.

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

iio: humidity: hts221: move drdy enable logic in hts221_trig_set_state()

Move data-ready configuration in hts221_buffer.c since it is only related
to trigger logic

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221: support open drain mode

Add open drain support in order to share requested IRQ line between
hts221 device and other peripherals

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221: support active-low interrupts

Add support for active low interrupts (IRQF_TRIGGER_LOW and
IRQF_TRIGGER_FALLING). Configure the device as active high or low
according to the requested irq line.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221: squash hts221_power_on/off in hts221_set_enable

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: humidity: hts221: Remove unnecessary cast on void pointer

The following Coccinelle script was used to detect this:
@r@
expression x;
void* e;
type T;
identifier f;
@@
(
*((T *)e)
|
((T *)x)[...]
|
((T*)x)->f
|
- (T*)
e
)

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: humidity: remove duplicated include from hts221_buffer.c

Remove duplicated include.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: humidity: add support to hts221 rh/temp combo device

Add support to STM HTS221 humidity + temperature sensor

http://www.st.com/resource/en/datasheet/hts221.pdf

- continuous mode support
- i2c support
- spi support
- trigger mode support

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>