iio: core: make iio_bus_type const

Now that the driver core can properly handle constant struct bus_type,
move the iio_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240208-bus_cleanup-iio-v1-1-4a167c3b5fb3@marliere.net
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: locking: introduce __cleanup() based direct mode claiming infrastructure

Allows use of:

iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
}

to automatically call iio_device_release_direct_mode() based on scope.
Typically seen in combination with local device specific locks which
are already have automated cleanup options via guard(mutex)(&st->lock)
and scoped_guard(). Using both together allows most error handling to
be automated.

Reviewed-by: Nuno Sa <nuno.a@analog.com>
Link: https://lore.kernel.org/r/20240128150537.44592-2-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: linux/iio.h: fix Excess kernel-doc description warning

Remove the @of_xlate: lines to prevent the kernel-doc warning:

include/linux/iio/iio.h:534: warning: Excess struct member 'of_xlate' description in 'iio_info'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-iio@vger.kernel.org
Link: https://lore.kernel.org/r/20231223050556.13948-1-rdunlap@infradead.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: event: add optional event label support

This adds a new optional field to struct iio_info to allow drivers to
specify a label for the event. This is useful for cases where there are
many events or the event attribute name is not descriptive enough or
where an event doesn't have any other attributes.

The implementation is based on the existing label support for channels.
So either all events of a device have a label attribute or none do.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231005-ad2s1210-mainline-v4-12-ec00746840fc@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: improve doc for available_scan_mask

The available_scan_mask is an array of bitmaps representing the channels
which can be simultaneously enabled by the driver. In many cases, the
hardware can offer more channels than what the user is interested in
obtaining. In such cases, it may be preferred that only a subset of
channels are enabled, and the driver reads only a subset of the channels
from the hardware.

Some devices can't support all channel combinations. For example, the
BM1390 pressure sensor must always read the pressure data in order to
acknowledge the watermark IRQ, while reading temperature can be omitted.
So, the available scan masks would be 'pressure and temperature' and
'pressure only'.

When IIO searches for the scan mask it asks the driver to use, it will
pick the first suitable one from the 'available_scan_mask' array. Hence,
ordering the masks in the array makes a difference. We should 'prefer'
reading just the pressure from the hardware (as it is a cheaper operation
than reading both pressure and temperature) over reading both pressure
and temperature. Hence, we should set the 'only pressure' as the first
scan mask in available_scan_mask array. If we set the 'pressure and
temperature' as first in the array, then the 'only temperature' will never
get used as 'pressure and temperature' can always serve the user's
needs.

Add (minimal) kerneldoc to the 'available_scan_mask' to hint the user
that the ordering of masks matters.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/4e43bf0186df5c8a56b470318b4827605f9cad6c.1695727471.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Point users of extend_name field to read_label callback

As mentioned and discussed in [1] extend_name should not be used for
full channel labels (and most drivers seem to only use it to express a
short type of a channel) as this affects sysfs filenames, while the
label name is supposed to be extracted from the *_label sysfs file
instead. This appears to have been unclear to some drivers as
extend_name is also used when read_label is unset, achieving an initial
goal of providing sensible names in *_label sysfs files without noticing
that sysfs filenames are (negatively and likely unintentionally)
affected as well.

Point readers of iio_chan_spec::extend_name to iio_info::read_label by
mentioning deprecation and side-effects of this field.

[1]: https://lore.kernel.org/linux-arm-msm/20221221223432.si2aasbleiicayfl@SoMainline.org/

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Link: https://lore.kernel.org/r/20230502-iio-adc-propagate-fw-node-label-v3-1-6be5db6e6b5a@somainline.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN

ARCH_DMA_MINALIGN represents the minimum (static) alignment for safe DMA
operations while ARCH_KMALLOC_MINALIGN is the minimum kmalloc() objects
alignment.

Link: https://lkml.kernel.org/r/20230612153201.554742-11-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

iio: add struct declaration for iio types

Add struct for iio type arrays such as IIO_AVAIL_LIST which can be used
instead of int arrays.

Signed-off-by: Gerald Loacker <gerald.loacker@wolfvision.net>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221201072220.402585-2-gerald.loacker@wolfvision.net
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: move 'mlock' to 'struct iio_dev_opaque'

Now that there are no more users accessing 'mlock' directly, we can move
it to the iio_dev private structure. Hence, it's now explicit that new
driver's should not directly use this lock.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20221012151620.1725215-5-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: introduce iio_device_{claim|release}_buffer_mode() APIs

These APIs are analogous to iio_device_claim_direct_mode() and
iio_device_release_direct_mode() but, as the name suggests, with the
logic flipped. While this looks odd enough, it will have at least two
users (in following changes) and it will be important to move the IIO
mlock to the private struct.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20221012151620.1725215-2-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: inkern: remove OF dependencies

Since all users of the OF dependendent API are now converted to use the
firmware agnostic alternative, we can drop OF dependencies from the IIO
in kernel interface.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220715122903.332535-15-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: inkern: move to fwnode properties

This moves the IIO in kernel interface to use fwnode properties and thus
be firmware agnostic.

Note that the interface is still not firmware agnostic. At this point we
have both OF and fwnode interfaces so that we don't break any user. On
top of this we also want to have a per driver conversion and that is the
main reason we have both of_xlate() and fwnode_xlate() support.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220715122903.332535-6-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: move trig->owner init to trigger allocate() stage

To provide a new IIO trigger to the IIO core, usually driver executes the
following pipeline: allocate()/register()/get(). Before, IIO core assigned
trig->owner as a pointer to the module which registered this trigger at
the register() stage. But actually the trigger object is owned by the
module earlier, on the allocate() stage, when trigger object is
successfully allocated for the driver.

This patch moves trig->owner initialization from register()
stage of trigger initialization pipeline to allocate() stage to
eliminate all misunderstandings and time gaps between trigger object
creation and owner acquiring.

Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Link: https://lore.kernel.org/r/20220601174837.20292-1-ddrokosov@sberdevices.ru
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: drop of.h from iio.h

There is no reason to include OF as we only need to forward declare
'of_phandle_args'. Previously, some drivers were actually relying on
this for some headers (those were already fixed).

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220610084545.547700-20-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Fix IIO_ALIGN and rename as it was not sufficiently large

Discussion of the series:
https://lore.kernel.org/all/20220405135758.774016-1-catalin.marinas@arm.com/
mm, arm64: Reduce ARCH_KMALLOC_MINALIGN brought to my attention that
our current IIO usage of L1CACHE_ALIGN is insufficient as their are Arm
platforms out their with non coherent DMA and larger cache lines at
at higher levels of their cache hierarchy.

Rename the define to make it's purpose more explicit. It will be used
much more widely going forwards (to replace incorrect ____cacheline_aligned
markings.

Note this patch will greatly reduce the padding on some architectures
that have smaller requirements for DMA safe buffers.

The history of changing values of ARCH_KMALLOC_MINALIGN via
ARCH_DMA_MINALIGN on arm64 is rather complex. I'm not tagging this
as fixing a particular patch from that route as it's not clear what to tag.

Most recently a change to bring them back inline was reverted because
of some Qualcomm Kryo cores with an L2 cache with 128-byte lines
sitting above the point of coherency.

c1132702c71f Revert "arm64: cache: Lower ARCH_DMA_MINALIGN to 64 (L1_CACHE_BYTES)"
That reverts:
65688d2a05de arm64: cache: Lower ARCH_DMA_MINALIGN to 64 (L1_CACHE_BYTES) which
refers to the change originally being motivated by Thunder x1 performance
rather than correctness.

Fixes: 6f7c8ee585e9d ("staging:iio: Add ability to allocate private data space to iio_allocate_device")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-2-jic23@kernel.org

iio: core: drop iio_get_time_res()

This function was introduced with the ability to pick a clock.
There are no upstream users so presumably it isn't as obviously useful
as it seemed at the time. Hence drop it.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20220220163327.424696-1-jic23@kernel.org

iio: core: Clarify the modes

As part of a previous discussion with Jonathan Cameron [1], it appeared
necessary to clarify the meaning of each mode so that new developers
could understand better what they should use or not use and when.

The idea of renaming these modes as been let aside because naming is a
big deal and requires a lot of thinking. So for now let's focus on
correctly explaining what each mode implies.

[1] https://lore.kernel.org/linux-iio/20210930165510.2295e6c4@jic23-huawei/

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220207143840.707510-14-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Move the currentmode entry to the opaque structure

This entry should, under no situation, be modified by device
drivers. Now that we have limited its read access to device drivers
really needing it and did so through a dedicated helper, we can
easily move this variable to the opaque structure in order to
prevent any further modification from non-authorized code (out of the
core, basically).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20220207143840.707510-12-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Hide read accesses to iio_dev->currentmode

In order to later move this variable within the opaque structure, let's
create a helper for accessing it in read-only mode. This helper will be
exposed to device drivers and kept accessible for the few that could need
it. The write access to this variable however should be fully reserved to
the core so in a second step we will hide this variable into the opaque
structure.

Cc: Eugen Hristev <eugen.hristev@microchip.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220207143840.707510-11-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Un-inline iio_buffer_enabled()

As we are going to hide the currentmode inside the opaque structure,
this helper would soon need to call a non-inline function which would
simply drop the benefit of having the helper defined inline in a header.

One alternative is to move this helper in the core as there is no more
interest in defining it inline in a header. We will pay the minor cost
either way.

Let's do like the iio_device_id() helper which also refers to the opaque
structure and gets defined in the core.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220207143840.707510-10-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Enhance the kernel doc of modes and currentmodes iio_dev entries

Let's provide more details about these two variables because their
understanding may not be straightforward for someone not used to the IIO
subsystem internal logic. The different modes will soon be also be more
documented for the same reason.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220207143840.707510-2-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Fix the kernel doc regarding the currentmode iio_dev entry

This is an internal variable, which should be accessed in a very
sporadic way and in no case changed by any device driver.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20211215151344.163036-2-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: expose shared parameter in IIO_ENUM_AVAILABLE

The shared parameter should be configurable based on its usage, and not
constrained to IIO_SHARED_BY_TYPE.

This patch aims to improve the flexibility in using the
IIO_ENUM_AVAILABLE define and avoid redefining custom iio enums that
expose the shared parameter.

An example is the ad5766.c driver where IIO_ENUM_AVAILABLE_SHARED was
defined in order to achieve `shared` parameter customization.

The current state of the IIO_ENUM_AVAILABLE implementation will imply
similar redefinitions each time a driver will require access to the
`shared` parameter. An example would be admv1013 driver which will
require custom device attribute for the frequency translation modes:
Quadrature I/Q mode and Intermediate Frequency mode.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20211119085627.6348-1-antoniu.miclaus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Drop Duplicated "mount-matrix" parameter

All of the users of iio_read_mount_matrix() are using the very same
property name. Moreover, the property name is hard coded in the API
documentation.

Make this clear and avoid duplication now and in the future.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sean Nyekjaer <sean@geanix.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210518112546.44592-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: move @clock_id from struct iio_dev to struct iio_dev_opaque

There is already an acessor function used to access it, making this
move straight forward.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-10-jic23@kernel.org

iio: core: move @flags from struct iio_dev to struct iio_dev_opaque

No reason any driver should ever need access to this field, so hide it.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-9-jic23@kernel.org

iio: core: move @chrdev from struct iio_dev to struct iio_dev_opaque

No reason for this to be exposed to the drivers, so lets move it to the
opaque structure.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-8-jic23@kernel.org

iio: core: move @info_exist_lock to struct iio_dev_opaque

This lock is only of interest to the IIO core, so make it only
visible there.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-7-jic23@kernel.org

iio: core: move @scan_index_timestamp to struct iio_dev_opaque

No reason for this cached value to be exposed to drivers so move it
to the opaque structure.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-6-jic23@kernel.org

iio: core: move @trig_readonly from struct iio_dev to struct iio_dev_opaque

This is only set via the iio_trig_set_immutable() call and later used
by the IIO core so there is no benefit in drivers being able to access
it.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-5-jic23@kernel.org

iio: core: move @driver_module from struct iio_dev to struct iio_dev_opaque

Continuing move to hide internal elements from drivers, move this structure
element over. It's only accessed from iio core files so this one was
straight forward and no accessor functions are needed.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-4-jic23@kernel.org

iio: core: move @id from struct iio_dev to struct iio_dev_opaque

Continuing from Alexandru Ardelean's introduction of the split between
driver modifiable fields and those that should only be set by the core.

This could have been done in two steps to make the actual move after
introducing iio_device_id() but there seemed limited point to that
given how mechanical the majority of the patch is.

Includes fixup from Alex for missing mxs-lradc-adc conversion.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-2-jic23@kernel.org

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: core: rework iio device group creation

Up until now, the device groups that an IIO device had were limited to 6.
Two of these groups would account for buffer attributes (the buffer/ and
scan_elements/ directories).

Since we want to add multiple buffers per IIO device, this number may not
be enough, when adding a second buffer. So, this change reallocates the
groups array whenever an IIO device group is added, via a
iio_device_register_sysfs_group() helper.

This also means that the groups array should be assigned to
'indio_dev.dev.groups' really late, right before {cdev_}device_add() is
called to do the entire setup.
And we also must take care to free this array when the sysfs resources are
being cleaned up.

With this change we can also move the 'groups' & 'groupcounter' fields to
the iio_dev_opaque object. Up until now, this didn't make a whole lot of
sense (especially since we weren't sure how multibuffer support would look
like in the end).
But doing it now kills one birds with one stone.

An alternative, would be to add a configurable Kconfig symbol
CONFIG_IIO_MAX_BUFFERS_PER_DEVICE (or something like that) and compute a
static maximum of the groups we can support per IIO device. But that would
probably annoy a few people since that would make the system less
configurable.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210215104043.91251-11-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Add optional symbolic label to a device channel

If a label is defined in the device tree for this channel add that
to the channel specific attributes. This is useful for userspace to
be able to identify an individual channel.

Signed-off-by: Cristian Pop <cristian.pop@analog.com>
Link: https://lore.kernel.org/r/20200928090959.88842-1-cristian.pop@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add __printf() attributes to various allocation functions

A partial set of these was added to IIO a long time back.
This fills in some gaps in coverage highlighted by building
with W=1

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200913132115.800131-3-jic23@kernel.org

iio: iio.h: fix a warning at the kernel-doc markup

There's a warning at iio.h kernel-doc markup:

./include/linux/iio/iio.h:644: WARNING: Unknown target name: "devm".

Because it is using {devm_}foo notation. Well, this is not
a valid kernel-doc notation. Also, it prevents creating hyperlinks
to other documentation functions.

So, replace it to a better notation.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/d8f2275c438c459ede4e6fba03ce719cc6ad898b.1599660067.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

iio: core: remove iio_priv_to_dev() helper

All users of this helper have been updated to not use it.
Remove it now, so that we don't need to move it when creating the
iio_dev_opaque structure.

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

iio: core: move event interface on the opaque struct

Same as with other private fields, this moves the event interface reference
to the opaque IIO device object, to be invisible to drivers.

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

iio: core: move iio_dev's buffer_list to the private iio device object

This change moves the 'buffer_list' away from the public IIO device object
into the private part.

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

iio: core: move channel list & group to private iio device object

This change bit straightforward and simple, since the
'channel_attr_list' & 'chan_attr_group' fields are only used in
'industrialio-core.c'.

This change moves to the private IIO device object

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

iio: core: move debugfs data on the private iio dev info

This change moves all iio_dev debugfs fields to the iio_dev_priv object.
It's not the biggest advantage yet (to the whole thing of abstractization)
but it's a start.

The iio_get_debugfs_dentry() function (which is moved in
industrialio-core.c) needs to also be guarded against the CONFIG_DEBUG_FS
symbol, when it isn't defined. We do want to keep the inline definition in
the iio.h header, so that the compiler can better infer when to compile out
debugfs code that is related to the IIO debugfs directory.

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

iio: core: wrap IIO device into an iio_dev_opaque object

There are plenty of bad designs we want to discourage or not have to review
manually usually about accessing private (marked as [INTERN]) fields of
'struct iio_dev'.

Sometimes users copy drivers that are not always the best examples.

A better idea is to hide those fields into the framework.
For 'struct iio_dev' this is a 'struct iio_dev_opaque' which wraps a public
'struct iio_dev' object.

In the next series, some fields will be moved to this new struct, each with
it's own rework.

This rework will not be complete-able for a while, as many fields need some
drivers to be reworked in order to finalize them (e.g. 'indio_dev->mlock').

But some fields can already be moved, and in time, all of them may get
there (in the 'struct iio_dev_opaque' object).

Since a lot of drivers also call 'iio_priv()', in order to preserve
fast-paths (where this matters), the public iio_dev object will have a
'priv' field that will have the pointer to the private information already
computed. The reference returned by this field should be guaranteed to be
cacheline aligned.

The opaque parts will be moved into the 'include/linux/iio/iio-opaque.h'
header. Should the hidden information be required for some debugging or
some special needs, it can be made available via this header.
Otherwise, only the IIO core files should include this file.

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

iio: core: add iio_device_set_parent() helper

By default, the device allocation will also assign a parent device to the
IIO device object. In cases where devm_iio_device_alloc() is used,
sometimes the parent device must be different than the device used to
manage the allocation.

In that case, this helper should be used to change the parent, hence the
requirement to call this between allocation & registration.

This pattern/requirement is not very common in the IIO space, and it may be
cleaned up later.
But until then, assigning the parent manually between allocation &
registration is slightly easier.

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

iio: core: pass parent device as parameter during allocation

The change passes the parent device to the iio_device_alloc() call. This
also updates the devm_iio_device_alloc() call to consider the device object
as the parent device by default.

Having it passed like this, should ensure that any IIO device object
already has a device object as parent, allowing for neater control, like
passing the 'indio_dev' object for other stuff [like buffers/triggers/etc],
and potentially creating iiom_xxx(indio_dev) functions.

With this patch, only the 'drivers/platform/x86/toshiba_acpi.c' needs an
update to pass the parent object as a parameter.

In the next patch all devm_iio_device_alloc() calls will be handled.

Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: make iio_device_get_drvdata take a const struct iio_dev *.

As this just calls dev_get_drvdata underneath which is happy with
a const struct device * we should change and avoid potentially
casting away a const in order to then put it back again.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: remove extra semi-colon from devm_iio_device_register() macro

This change removes the semi-colon from the devm_iio_device_register()
macro which seems to have been added by accident.

Fixes: 63b19547cc3d9 ("iio: Use macro magic to avoid manual assign of driver_module")
Signed-off-by: Lars Engebretsen <lars@engebretsen.ch>
Cc: <Stable@vger.kernel.org>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: drop devm_iio_trigger_free() API call

It's unused so far, so it can be removed. Also makes sense to remove it
to discourage weird uses of this call during review.

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

iio: core: drop devm_iio_device_free() API call

It's unused so far, so it can be removed. Also makes sense to remove it
to discourage weird uses of this call during review.

This is the last user of 'devm_iio_device_match()', so it can be removed as
well in this patch.

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

iio: core: drop devm_iio_device_unregister() API call

It's unused so far, so it can be removed. Also makes sense to remove it
to discourage weird uses of this call during review.

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

iio: expose iio_device_set_clock

Some IIO devices may want to override the default (realtime) to another
clock source by default.

It can beneficial when timestamps coming from the hardware or underlying
drivers are already in that format.

It can always be overridden by attribute current_timestamp_clock.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

iio: core: Make mlock internal to the iio core

"mlock" should ideally only be used by the iio core. The mlock
implementation may change in the future which means that no driver
should be explicitly using mlock.

Signed-off-by: Rohit Sarkar <rohitsarkar5398@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: industrialio-core: Fix debugfs read

Currently iio_debugfs_read_reg calls debugfs_reg_access
every time it is ran. Reading the same hardware register
multiple times during the same reading of a debugfs file
can cause unintended effects.

For example for each: cat iio:device0/direct_reg_access
the file_operations.read function will be called at least
twice. First will return the full length of the string in
bytes and the second will return 0.

This patch makes iio_debugfs_read_reg to call debugfs_reg_access
only when the user's buffer position (*ppos) is 0. (meaning
it is the beginning of a new reading of the debugfs file).

Fixes: e553f182d55b ("staging: iio: core: Introduce debugfs support, add support for direct register access")
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Add optional symbolic label to device attributes

If a label is defined in the device tree for this device add that
to the device specific attributes. This is useful for userspace to
be able to identify an individual device when multiple identical
chips are present in the system.

Tested-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Phil Reid <preid@electromag.com.au>
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: Allow to read mount matrix from ACPI

Currently mount matrix is allowed in Device Tree, though there is
no technical issue to extend it to support ACPI.

Convert the function to use device_property_read_string_array() and
thus allow to read mount matrix from ACPI if available.

Example of use in _DSD method:

Name (_DSD, Package ()
{
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package ()
{
Package () { "mount-matrix", Package() {
"1", "0", "0",
"0", "0.866", "0.5",
"0", "-0.5", "0.866",
} },
}
})

At the same time drop the "of" prefix from its name and
convert current users.

No functional change intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: iio.h: use nested struct support on kernel-doc markup

Solve those Sphinx warnings:

./include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.sign' not described in 'iio_chan_spec'
./include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.realbits' not described in 'iio_chan_spec'
./include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.storagebits' not described in 'iio_chan_spec'
./include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.shift' not described in 'iio_chan_spec'
./include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.repeat' not described in 'iio_chan_spec'
./include/linux/iio/iio.h:270: warning: Function parameter or member 'scan_type.endianness' not described in 'iio_chan_spec'

./include/linux/iio/iio.h:191: WARNING: Unexpected indentation.
./include/linux/iio/iio.h:192: WARNING: Block quote ends without a blank line; unexpected unindent.
./include/linux/iio/iio.h:198: WARNING: Definition list ends without a blank line; unexpected unindent.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

IIO: inkern: API for manipulating channel attributes

Extend the inkern API with functions for reading and writing
attribute of iio channels.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

iio: fix SPHINX kernel-docs build warning

When building kernel documentation sphinx emits the following warnings

No description found for parameter 'iio_dev'
Excess function parameter 'indio_dev' description in 'iio_device_register'

These warnings are caused by a macro with a different argument identifier to the
one listed in the kernel-docs.

Change macro argument to be the same as the docs.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: Drop duplicate forward declaration

Commit 5f420b42079c ("staging:iio: Add extended IIO channel info") added
a forward declaration for struct iio_dev to <linux/iio/iio.h> but forgot
to remove an existing forward declaration further down originating from
commit 7ae8cf627558 ("staging: iio: chrdev.h rationalization").

Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: drop iio_info.driver_module and iio_trigger_ops.owner.

The equivalents are now assigned automatically in the relevant
registration calls and so are not needed in these operations
structures.

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

iio: Use macro magic to avoid manual assign of driver_module

Starting point in boiler plate reduction similar to that done for
many similar cases elsewhere in the kernel.

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

PATCH] iio: Fix some documentation warnings

The kerneldoc description for the trig_readonly field of struct iio_dev
lacked a colon, leading to this doc build warning:

./include/linux/iio/iio.h:603: warning: No description found for parameter 'trig_readonly'

A similar issue for iio_trigger_set_immutable() in trigger.h yielded:

./include/linux/iio/trigger.h:151: warning: No description found for parameter 'indio_dev'
./include/linux/iio/trigger.h:151: warning: No description found for parameter 'trig'

Fix the formatting and silence the warnings.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: add hardware triggered operating mode

Devices, like stm32 timer, could be triggered by hardware events which
are not buffer or software events. However it could be necessary to
validate the triggers like it is done for buffer or event triggered modes.
This patch add a new INDIO_HARDWARE_TRIGGERED operating mode for this
kind of devices and allow this mode to register trigger consumer.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: inkern: add helpers to query available values from channels

Specifically a helper for reading the available maximum raw value of a
channel and a helper for forwarding read_avail requests for raw values
from one iio driver to an iio channel that is consumed.

These rather specific helpers are in turn built with generic helpers
making it easy to build more helpers for available values as needed.

Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:core: add a callback to allow drivers to provide _available attributes

A large number of attributes can only take a limited range of values.
Currently in IIO this is handled by directly registering additional
*_available attributes thus providing this information to userspace.

It is desirable to provide this information via the core for much the same
reason this was done for the actual channel information attributes in the
first place. If it isn't there, then it can only really be accessed from
userspace. Other in kernel IIO consumers have no access to what valid
parameters are.

Two forms are currently supported:
* list of values in one particular IIO_VAL_* format.
e.g. 1.300000 1.500000 1.730000
* range specification with a step size:
e.g. [1.000000 0.500000 2.500000]
equivalent to 1.000000 1.5000000 2.000000 2.500000

An addition set of masks are used to allow different sharing rules for the
*_available attributes generated.

This allows for example:

in_accel_x_offset
in_accel_y_offset
in_accel_offset_available.

We could have gone with having a specification for each and every
info_mask element but that would have meant changing the existing userspace
ABI. This approach does not.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
[forward ported, added some docs and fixed buffer overflows /peda]
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Declare event_attrs field of iio_info structure as const

The event_attrs field of iio_info structure is only initialized once
whenever an object of iio_info is created. After that this field
is never modified again anywhere in the kernel. So, declare event_attrs
field of iio_info as a const struct attribute_group.
Checked for occurences throughout the kernel using grep and
coccinelle.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: add resource managed triggered buffer init helpers

Add resource managed devm_iio_triggered_buffer_setup() and
devm_iio_triggered_buffer_cleanup() to automatically clean up triggered
buffers setup by IIO drivers, thus leading to simplified IIO drivers code.

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

iio: trigger: allow immutable triggers to be assigned

There are times when an assigned trigger to a device shouldn't ever
change after intialization.

Examples of this being used is when an provider device has a trigger
that is assigned to an ADC, which uses it populate data into a callback
buffer.

Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

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:core: mounting matrix support

Expose a rotation matrix to indicate userspace the chip placement with
respect to the overall hardware system. This is needed to adjust
coordinates sampled from a sensor chip when its position deviates from the
main hardware system.

Final coordinates computation is delegated to userspace since:
* computation may involve floating point arithmetics ;
* it allows an application to combine adjustments with arbitrary
transformations.

This 3 dimentional space rotation matrix is expressed as 3x3 array of
strings to support floating point numbers. It may be retrieved from a
"[<dir>_][<type>_]mount_matrix" sysfs attribute file. It is declared into a
device / driver specific DTS property or platform data.

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

iio: core: implement iio_device_{claim|release}_direct_mode()

It is often the case that the driver wants to be sure a device stays
in direct mode while it is executing a task or series of tasks. To
accomplish this today, the driver performs this sequence: 1) take the
device state lock, 2) verify it is not in a buffered mode, 3) execute
some tasks, and 4) release that lock.

This patch introduces a pair of helper functions that simplify these
steps and make it more semantically expressive.

iio_device_claim_direct_mode()
If the device is not in any buffered mode it is guaranteed
to stay that way until iio_release_direct_mode() is called.

iio_device_release_direct_mode()
Release the claim. Device is no longer guaranteed to stay
in direct mode.

Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Fix typos in the struct iio_event_spec documentation comments

This patch fixes a few minor typos in the documentation comments for the
scan_type member of the iio_event_spec structure. The sign member name
was improperly capitalized as "Sign" in the comments. The storagebits
member name was improperly listed as "storage_bits" in the comments. The
endianness member entry in the comments was moved after the repeat
member entry in order to maintain consistency with the actual struct
iio_event_spec layout.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Fix documentation for iio_dev mlock

mlock *must* be used by core and drivers to protect access
to devices state changes.

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Make IIO value formating function globally available.

Make IIO value formating function globally available to allow IIO drivers
to output values as the core does.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Support triggered events

Support triggered events.

This is useful for chips that don't have their own interrupt sources.
It allows to use generic/standalone iio triggers for those drivers.

Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add inverse unit conversion macros

Add inverse unit conversion macro to convert from standard IIO units to
units that might be used by some devices.

Those are useful in combination with scale factors that are specified as
IIO_VAL_FRACTIONAL. Typically the denominator for those specifications will
contain the maximum raw value the sensor will generate and the numerator
the value it maps to in a specific unit. Sometimes datasheets specify those
in different units than the standard IIO units (e.g. degree/s instead of
rad/s) and so we need to do a unit conversion.

From a mathematical point of view it does not make a difference whether we
apply the unit conversion to the numerator or the inverse unit conversion
to the denominator since (x / y) / z = x / (y * z). But as the denominator
is typically a larger value and we are rounding both the numerator and
denominator to integer values using the later method gives us a better
precision (E.g. the relative error is smaller if we round 8000.3 to 8000
rather than rounding 8.3 to 8).

This is where in inverse unit conversion macros will be used.

Marked for stable as used by some upcoming fixes.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: add high pass filter attributes

Add a high pass filter attribute for measurements
(like the existing low pass)

Also add both high and low pass attributes for events.

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Introduce IIO_CHAN_INFO_OVERSAMPLING_RATIO

Some magnetometers can perform a number of repetitions in HW
for each measurement to increase accuracy. One example is
Bosch BMC150:
http://ae-bst.resource.bosch.com/media/products/dokumente/bmc150/BST-BMC150-DS000-04.pdf.

Introduce an interface to set the oversampling ratio
for these devices.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Introduce IIO_CHAN_INFO_CALIBEMISSIVITY

Contact-less IR temperature sensors measure the temperature of an object
by using its thermal radiation. Surfaces with different emissivity
ratios emit different amounts of energy at the same temperature.

IIO_CHAN_INFO_CALIBEMISSIVITY allows the user to inform the sensor of the
emissivity of the object in front of it, in order to effectively measure
its temperature.

A device providing such setting is Melexis's MLX90614:
http://melexis.com/Assets/IR-sensor-thermometer-MLX90614-Datasheet-5152.aspx.

Signed-off-by: Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>
Cc: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: add support for hardware fifo

Some devices have hardware buffers that can store a number of samples
for later consumption. Hardware usually provides interrupts to notify
the processor when the FIFO is full or when it has reached a certain
watermark level. This helps with reducing the number of interrupts to
the host processor and thus it helps decreasing the power consumption.

This patch enables usage of hardware FIFOs for IIO devices in
conjunction with software device buffers. When the hardware FIFO is
enabled the samples are stored in the hardware FIFO. The samples are
later flushed to the device software buffer when the number of entries
in the hardware FIFO reaches the hardware watermark or when a flush
operation is triggered by the user when doing a non-blocking read
on an empty software device buffer.

In order to implement hardware FIFO support the device drivers must
implement the following new operations: setting and getting the
hardware FIFO watermark level, flushing the hardware FIFO to the
software device buffer. The device must also expose information about
the hardware FIFO such it's minimum and maximum watermark and if
necessary a list of supported watermark values. Finally, the device
driver must activate the hardware FIFO when the device buffer is
enabled, if the current device settings allows it.

The software device buffer watermark is passed by the IIO core to the
device driver as a hint for the hardware FIFO watermark. The device
driver can adjust this value to allow for hardware limitations (such
as capping it to the maximum hardware watermark or adjust it to a
value that is supported by the hardware). It can also disable the
hardware watermark (and implicitly the hardware FIFO) it this value is
below the minimum hardware watermark.

Since a driver may support hardware FIFO only when not in triggered
buffer mode (due to different semantics of hardware FIFO sampling and
triggered sampling) this patch changes the IIO core code to allow
falling back to non-triggered buffered mode if no trigger is enabled.

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Introduce IIO_CHAN_INFO_DEBOUNCE_COUNT and _TIME

The pedometer needs to filter out false steps that might be generated by
tapping the foot, sitting, etc. To do that it computes the number of
steps that occur in a given time and decides the user is moving only
if this value is over a threshold. E.g.: the user starts moving only
if he takes 4 steps in 3 seconds. This filter is applied only when
the user starts moving.

A device that has such pedometer functionality is Freescale's MMA9553L:
http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf.

To export this feature, this patch introduces IIO_CHAN_INFO_DEBOUNCE_COUNT
and IIO_CHAN_INFO_DEBOUNCE_TIME. For the pedometer, in_steps_debounce_count
will specify the number of steps that need to occur in
in_steps_debounce_time seconds so that the pedometer decides the user is
moving.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Introduce IIO_CHAN_INFO_CALIBWEIGHT

Some devices need the weight of the user to compute other
parameters. One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that needs the weight of the user to compute the number of calories burnt.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add new operating mode for non triggered sw buffers

There was a need for non triggered software buffer type. It can be used when
triggered model does not fit and INDIO_BUFFER_HARDWARE causes confusion because
the data stream can be obtained not directly form hardware backend.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Karol Wrona <k.wrona@samsung.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Introduce IIO_CHAN_INFO_CALIBHEIGHT

Some devices need the height of the user to compute various
parameters. One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that needs the height of the user to compute the stride length which
is used further to determine distance, speed and activity type.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Introduce STEPS channel, ENABLE mask and INSTANCE event

These changes are needed to support the functionality of a pedometer.
A pedometer has two basic functionalities: step counter and step detector.

The step counter needs to be enabled and then it will count the steps
in its hardware register. Whenever the application needs to check
the step count, it will read the step counter register. To support the
step counter a new channel type STEPS is added. Since the pedometer needs
to be enabled first so that the hardware can count and store the steps,
we need a specific ENABLE channel info mask.

The step detector will generate an interrupt each time a step is detected.
To support this functionality we add a new event type INSTANCE.

For more information on the Android requirements for step counter and step
detector see:
http://source.android.com/devices/sensors/composite_sensors.html#counter
and http://source.android.com/devices/sensors/composite_sensors.html#detector.

A device that has the pedometer functionality this interface needs to
support is Freescale's MMA9553L:
http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: inkern: Add of_xlate function to struct iio_info

When #iio-cells is greater than '0', the driver could provide
a custom of_xlate function that reads the *args* and returns
the appropriate index in registered IIO channels array.

Add simple translation function, suitable for the most 1:1
mapped channels in IIO chips, and use it when driver did not
provide custom implementation.

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Use ktime_get_real_ns()

No idea why iio needs wall clock based time stamps, but we can avoid
the timespec conversion dance by using the new interfaces.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>

IIO: core: Modify scan element type

The current scan element type uses the following format:
[be|le]:[s|u]bits/storagebits[>>shift].
To specify multiple elements in this type, added a repeat value.
So new format is:
[be|le]:[s|u]bits/storagebitsXr[>>shift].
Here r is specifying how may times, real/storage bits are repeating.

When X is value is 0 or 1, then repeat value is not used in the format,
and it will be same as existing format.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

IIO: core: Introduce read_raw_multi

This callback is introduced to overcome some limitations of existing
read_raw callback. The functionality of both existing read_raw and
read_raw_multi is similar, both are used to request values from the
device. The current read_raw callback allows only two return values.
The new read_raw_multi allows returning multiple values. Instead of
passing just address of val and val2, it passes length and pointer
to values. Depending on the type and length of passed buffer, iio
client drivers can return multiple values.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:drop IIO_ST macro

This macro no longer allows all the elements of the scan_type structure
to be set. Missinterpretation of the parameters also caused a couple of
recent bugs. No mainline drivers now use this macro so drop it.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Remove support for the legacy event config interface

Now that all drivers have been converted to the new event config interface we
can remove for the legacy event config interface. Also drop the '_new' suffix
for the event config interface callbacks, since those are the only callbacks
now.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Move kernel doc to the right location

Documentation related to function should be placed above
its implementation. Move it accordingly.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Implement devm_iio_device_{register,unregister}

Add device managed devm_iio_device_{register,unregister}()
to automatically unregister IIO drivers thus leading to
simplified IIO driver code.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Extend the event config interface

The event configuration interface of the IIO framework has not been getting the
same attention as other parts. As a result it has not seen the same improvements
as e.g. the channel interface has seen with the introduction of the channel spec
struct. Currently all the event config callbacks take a u64 (the so called event
code) to pass all the different information about for which event the callback
is invoked. The callback function then has to extract the information it is
interested in using some macros with rather long names. Most information encoded
in the event code comes straight from the iio_chan_spec struct the event was
registered for. Since we always have a handle to the channel spec when we call
the event callbacks the first step is to add the channel spec as a parameter to
the event callbacks. The two remaining things encoded in the event code are the
type and direction of the event. Instead of passing them in one parameter, add
one parameter for each of them and remove the eventcode from the event
callbacks. The patch also adds a new iio_event_info parameter to the
{read,write}_event_value callbacks. This makes it possible, similar to the
iio_chan_info_enum for channels, to specify additional properties other than
just the value for an event. Furthermore the new interface will allow to
register shared events. This is e.g. useful if a device allows configuring a
threshold event, but the threshold setting is the same for all channels.

To implement this the patch adds a new iio_event_spec struct which is similar to
the iio_chan_spec struct. It as two field to specify the type and the direction
of the event. Furthermore it has a mask field for each one of the different
iio_shared_by types. These mask fields holds which kind of attributes should be
registered for the event. Creation of the attributes follows the same rules as
the for the channel attributes. E.g. for the separate_mask there will be a
attribute for each channel with this event, for the shared_by_type there will
only be one attribute per channel type. The iio_chan_spec struct gets two new
fields, 'event_spec' and 'num_event_specs', which is used to specify which the
events for this channel. These two fields are going to replace the channel's
event_mask field.

For now both the old and the new event config interface coexist, but over the
few patches all drivers will be converted from the old to the new interface.
Once that is done all code for supporting the old interface will be removed.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: add info_mask_[shared_by_dir/shared_by_all]

These two additional info_mask bitmaps should allow all 'standard'
numeric attributes to be handled using the read_raw and write_raw
callbacks. Whilst this should reduce code, the more important element
is that this makes these values easily accessible to in kernel users
of IIO devices.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

iio: refactor info mask and ext_info attribute creation.

Introduce an enum to specify whether the attribute is separate or
shared.

Factor out the bitmap handling for loop into a separate function.

Tidy up error handling and add a NULL assignment to squish a false
positive warning from GCC.

Change ext_info shared type from boolean to enum and update in all
drivers.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

iio: drop info_mask from struct iio_dev

Somehow this got missed when dropping all the code that used it
prior to the split. Remove it now, there are no users.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

iio: Add INT_TIME (integration time) channel info attribute

Integration time is in seconds; it controls the measurement
time and influences the gain of a sensor.

There are two typical ways that scaling is implemented in a device:
1) input amplifier,
2) reference to the ADC is changed.
These both result in the accuracy of the ADC varying (by applying its
sampling over a more relevant range).

Integration time is a way of dealing with noise inherent in the analog
sensor itself. In the case of a light sensor, a mixture of photon noise
and device specific noise. Photon noise is dealt with by either improving
the efficiency of the sensor, (more photons actually captured) which is not
easily varied dynamically, or by integrating the measurement over a longer
time period. Note that this can also be thought of as an averaging of a
number of individual samples and is infact sometimes implemented this way.
Altering integration time implies that the duration of a measurement changes,
a fact the device's user may be interested in.

Hence it makes sense to distinguish between integration time and simple
scale. In some devices both types of control are present and whilst they
will have similar effects on the amplitude of the reading, their effect
on the noise of the measurements will differ considerably.

Used by adjd_s311, tsl4531, tcs3472
The following drivers have similar controls (and could be adapted):
* tsl2563 (integration time is controlled via CALIBSCALE among other things)
* tsl2583 (has integration_time device_attr, but driver doesn't use channels yet)
* tsl2x7x (has integration_time attr)

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Jon Brenner <jon.brenner@ams.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Remove trailing ; from function definitions

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: trigger: implement devm_iio_trigger_alloc/devm_iio_triger_free

Add a resource managed devm_iio_trigger_alloc()/devm_iio_triger_free()
to automatically clean up triggers allocated by IIO drivers, thus
leading to simplified IIO drivers code.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Kyunmin Park <kyungmin.park@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Fix documentation of devm_iio_device_free()

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: implement devm_iio_device_alloc/devm_iio_device_free

Add a resource managed devm_iio_device_alloc()/devm_iio_device_free()
to automatically clean up any allocations made by IIO drivers,
thus leading to simplified IIO drivers code.

In addition, this will allow IIO drivers to use other devm_*() API
(like devm_request_irq) and don't care about the race between
iio_device_free() and the release of resources by Device core
during driver removing.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Tested-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Fix iio_channel_has_info

Since the info_mask split, iio_channel_has_info() is not working correctly.
info_mask_separate and info_mask_shared_by_type, it is not possible to compare
them directly with the iio_chan_info_enum enum. Correct that bit using the BIT()
macro.

Cc: <stable@vger.kernel.org> # 3.10.x
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:core drop info_mask from struct iio_info

This has been replaced by the pair of masks info_mask_separate
and info_mask_shared_by_type. Other variants may follow.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>

iio: Add broken out info_mask fields for shared_by_type and separate

This simplifies the code, removes an extensive layer of 'helper' macros
and gives us twice as much room to play with in these masks before we
have any need to be clever.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>

iio: Factor out fixed point number parsing into its own function

Factor out the code for parsing fixed point numbers into its own function and
make this function globally available. This allows us to reuse the code to parse
fixed point numbers in individual IIO drivers.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

staging:iio: Add support for multiple buffers

Route all buffer writes through the demux.
Addition or removal of a buffer results in tear down and
setup of all the buffers for a given device.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Tested-by: srinivas pandruvada <srinivas.pandruvada@intel.com>

iio: Add some helper macros for unit conversion

Some datasheets use a different unit to specify the channel scale than what IIO
expects it to be. This patch adds two helper macros which allow to convert units
commonly used in datasheets to IIO units:

* acceleration: g -> meter / second**2
* angular velocity: degree (/ second) -> rad (/ second)

This makes it much more convenient to specify and also easier to verify a
channel's scale attribute.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:inkern: Add function to read the processed value

Add a function to read a processed value from a channel. The function will first
attempt to read the IIO_CHAN_INFO_PROCESSED attribute. If that fails it will
read the IIO_CHAN_INFO_RAW attribute and convert the result from a raw value to
a processed value.

The patch also introduces a function to convert raw value to a processed value
and exports it, in case a user needs or wants to do the conversion by itself.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Add hysteresis in channel spec

Added hysteresis to the list of channel info enumeration, shared
/separate bit defines and to postfix channel info strings.

Signed-off-by: srinivas pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: whitespace cleanup and removal of semicolon after functions

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: fix typos

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: document missing elements

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Introduce iio_device_{set,get}_drvdata()

Introduce two new helper functions to attach a arbitrary pointer to a IIO
device. This is useful to get access to external non-global data from within a
IIO device callbacks where only the IIO device is available.

Internally these functions use dev_{set,get}_drvdata() on the struct device
embedded in the IIO device.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add callback to check whether a scan mask is valid

This is useful for cases where the number of valid scan masks grows
exponentially, but it is rather easy to check whether a mask is valid or not
programmatically.

An example of such a case is a device with multiple ADCs where each ADC has a
upstream MUX, which allows to select from a number of physical channels.

+-------+ +-------+
| | | | --- Channel 1
| ADC 1 |---| MUX 1 | --- ...
| | | | --- Channel M
+-------+ +-------+

. . .
. . .
. . .

+-------+ +-------+
| | | | --- Channel M * N + 1
| ADC N |---| MUX N | --- ...
| | | | --- Channel M * N + M
+-------+ +-------+

The number of necessary scan masks for this case is (M+1)**N - 1, on the other
hand it is easy to check whether subsets for each ADC of the scanmask have only
one bit set.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: typo in iio_chan_spec.ext_info comment

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: cleanup iio/iio.h

indentation of parameter description,
fix parameter name (@dev -> @indio_dev) in comments,
IIO device info structure -> IIO device structure

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: mark struct iio_enum elements with @ in comment

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: clarify channel and indexed in struct iio_chan_spec

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: fix typos in iio.h

v2:
* "used in in-kernel" (Jonathan Cameron)

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: Add helper functions for enum style channel attributes

We often have the case were we do have a enum style channel attribute. These
attributes have in common that they are a list of string values which usually
map in a 1-to-1 fashion to integer values.

This patch implements some common helper code for implementing enum style
channel attributes using extended channel attributes. The helper functions take
care of converting between the string and integer values, as well providing a
function for "_available" attributes which list all available enum items.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: Add iio_device_get()

This patch add the iio_device_get() function, which increases the reference
count of a iio device. The matching function to decrease the reference count -
iio_device_put() - already exists.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: Add dev_to_iio_dev() helper function

This patch adds a helper function for retriving a iio_dev struct from a device
struct. Currently we open-code this in two different ways. One is using
dev_get_drvdata on the device and the other is using container_of. The new
helper function uses the container_of solution as it creates slightly smaller
code and also will eventually free up the drvdata pointer for usage by invidual
drivers.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: core: introduce IIO_CHAN_INFO_HARDWAREGAIN

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: core: iio_chan_spec_ext_info: Add private handle

There is currently no user, but we might need it in future.
So better add it now, before we have to convert drivers afterwards.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: core: Introduce IIO_ALTVOLTAGE and appropriate channel info elements

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging:iio: Streamline API function naming

Currently we use two different naming schemes in the IIO API, iio_verb_object
and iio_object_verb. E.g iio_device_register and iio_allocate_device. This
patches renames instances of the later to the former. The patch also renames allocate to
alloc as this seems to be the preferred form throughout the kernel.

In particular the following renames are performed by the patch:
iio_put_device -> iio_device_put
iio_allocate_device -> iio_device_alloc
iio_free_device -> iio_device_free
iio_get_trigger -> iio_trigger_get
iio_put_trigger -> iio_trigger_put
iio_allocate_trigger -> iio_trigger_alloc
iio_free_trigger -> iio_trigger_free

The conversion was done with the following coccinelle patch with manual fixes to
comments and documentation.

<smpl>
@@
@@
-iio_put_device
+iio_device_put
@@
@@
-iio_allocate_device
+iio_device_alloc
@@
@@
-iio_free_device
+iio_device_free
@@
@@
-iio_get_trigger
+iio_trigger_get
@@
@@
-iio_put_trigger
+iio_trigger_put
@@
@@
-iio_allocate_trigger
+iio_trigger_alloc
@@
@@
-iio_free_trigger
+iio_trigger_free
</smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

IIO: Move core headers to include/linux/iio

Step 1 in moving the IIO core out of staging.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>