iio: humidity: hts211: Use devm_regulator_get_enable()

This driver only turns the power on at probe and off via a custom
devm_add_action_or_reset() callback. The new devm_regulator_get_enable()
replaces this boilerplate code.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20221016163409.320197-10-jic23@kernel.org

iio: humidity: hts221: add vdd voltage regulator

Like all other ST sensors, hts221 devices have VDD power line.
Introduce VDD voltage regulator to control it.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/6b3347e78f4f920c48eb6a66936d3b69cb9ff53a.1606045688.git.lorenzo@kernel.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: 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>

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: move common code in hts221_core

Move duplicated i2c/spi probe code in hts221_probe()

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 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: refactor write_with_mask code

Move bit-shift in hts221_write_with_mask() instead of coding
the shift depth in the configured value. That change will be necessary
to fix an issue in device power-down procedure.
Simplify hts221_avg_list table management

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

iio: humidity: hts221: add power management support

Add system sleep power management support to hts221 driver

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.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>