iio:st-sensors: Move exports into IIO_ST_SENSORS namespace

To avoid unnecessary pollution of the global symbol namespace move the
driver core and type specific core exports into their a new namespace
and import that where needed.

For more info see https://lwn.net/Articles/760045/

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Denis Ciocca <denis.ciocca@st.com>
Link: https://lore.kernel.org/r/20220116180535.2367780-14-jic23@kernel.org

iio: st_sensors: remove reference to parent device object on st_sensor_data

The idea behind it, is that all devm_ calls in ST sensors are bound to the
parent device object.

However, the reference to that object is kept on both the st_sensor_data
struct and the IIO object parent (indio_dev->dev.parent).

This change only adds a bit consistency and uses the reference stored on
indio_dev->dev.parent, to enforce the assumption that all ST sensors' devm_
calls are bound to the same reference as the one store on st_sensor_data.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210823112204.243255-6-aardelean@deviqon.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: st-sensors: Remove some unused includes and add some that should be there

The st-sensors drivers have changed in structure over time, and includes
have not always kept up with this. Let's bring them back to nearer
the ideal.

Identified with the include-what-you-use tool and careful checking of
its suggestions.

Note I haven't been particularly aggressive here, so this is just the
cases where the include obviously isn't needed rather than the more
subtle corners.

Note I took the opportunity to add mod_devicetable.h as I generally
prefer to see that when acpi or of match tables are present.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Denis Ciocca <denis.ciocca@st.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210608175149.4019289-1-jic23@kernel.org

iio: remove left-over parent assignments

These were found by doing some shell magic:
------------
for file in $(git grep -w devm_iio_device_alloc | cut -d: -f1 | sort | uniq) ; do
if grep 'parent =' $file | grep -v trig | grep -vq devm_; then
echo "$file -> $(grep "parent =" $file)"
fi
done
-----------

The output is bearable [after the semantic patch is applied].
There is a mix of trigger assignments with some iio device parent
assignments that are removed via this patch.

JC: A few more added via inspection of all parent =
statements in drivers/iio. Some of these may just have crossed with this
series, others were less obvious to scripting due to some cross
file / module boundary calls.

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

iio: st_sensors: Drop unneeded casting when print error code

Explicit casting in printf() usually shows that something is not okay.
Here, we really don't need it by providing correct specifier.

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

iio: st_sensors: 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>

iio: st_sensors: 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: remove get_irq_data_ready() function pointer and use IRQ number directly

Not even sure why it was there since the beginning. Just use IRQ
number in the sensor_data struct.

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: make st_sensors drivers use regmap

This patch is meant to replace the i2c/spi transfer functions with
regmap. SPI framework requires DMA safe buffers so let's add GFP_DMA
flag for memory allocation used by bulk_read functions.

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: move 3-wire spi initialization to st_sensors_spi

Some devices need to be configured with special bit in order to
use spi 3-wire. This was done during device identification phase.
Instead, let's move this part as spi specific.
Doing this the check_device_support function becomes a simple
device id check, so let's rename it.

Signed-off-by: Denis Ciocca <denis.ciocca@st.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: common: remove unnecessary sizeof(u8)

sizeof(u8) is always 1.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:common: Set the device pointer into ST common sensors library

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:common: Use spi_sync_transfer() in STMicroelectronics common library

Use the new spi_sync_transfer() helper function instead of open-coding it.

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:common: Add STMicroelectronics common library

This patch add a generic library for STMicroelectronics 3-axis sensors.

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>