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: core: use INDIO_ALL_BUFFER_MODES in iio_buffer_enabled()

This replaces use of individual buffer mode flags with
INDIO_ALL_BUFFER_MODES in the iio_buffer_enabled() function.

This simplifies the code and makes it robust in case of the addition of
new buffer modes.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240108200647.3916681-1-dlechner@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: fix memleak in iio_device_register_sysfs

When iio_device_register_sysfs_group() fails, we should
free iio_dev_opaque->chan_attr_group.attrs to prevent
potential memleak.

Fixes: 32f171724e5c ("iio: core: rework iio device group creation")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Link: https://lore.kernel.org/r/20231208073119.29283-1-dinghao.liu@zju.edu.cn
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: introduce trough info element for minimum values

The IIO_CHAN_INFO_PEAK info element is used for maximum values and
currently there is no equivalent for minimum values. Instead of
overloading the existing peak info element, a new info element can
be added.

In principle there is no need to add a _TROUGH_SCALE element as the
scale will be the same as the one required for INFO_PEAK, which in
turn is sometimes omitted if a single scale for peaks and raw values
is required.

Add an IIO_CHAN_INFO_TROUGH info element for minimum values.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20231211122747.9723-1-579lpy@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: add modifiers for A and B ultraviolet light

Currently there are only two modifiers for ultraviolet light: a generic
one for any ultraviolet light (IIO_MOD_LIGHT_UV) and one for deep
ultraviolet (IIO_MOD_LIGHT_DUV), which is also referred as ultraviolet
C (UV-C) band and covers short-wave ultraviolet.

There are still no modifiers for the long-wave and medium-wave
ultraviolet bands. These two bands are the main components used to
obtain the UV index on the Earth's surface.

Add modifiers for the ultraviolet A (UV-A) and ultraviolet B (UV-B)
bands.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20231110-veml6075-v3-1-6ee46775b422@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: sanity check available_scan_masks array

When IIO goes through the available scan masks in order to select the
best suiting one, it will just accept the first listed subset of channels
which meets the user's requirements. If driver lists a mask which is a
subset of some of the masks previously in the array of
avaliable_scan_masks, then the latter one will never be selected.

Add a warning if driver registers masks which can't be used due to the
available_scan_masks-array ordering.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/e55ef0b26a6d3b323bab24920c131c79a01ba08e.1697452986.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add channel type for chromaticity

In most cases, ambient color sensors also support the x and y light
colors, which represent the coordinates on the CIE 1931 chromaticity
diagram. Thus, add channel type for chromaticity.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Link: https://lore.kernel.org/r/20230919081054.2050714-7-Basavaraj.Natikar@amd.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add channel type light color temperature

In most cases, ambient color sensors also support light color
temperature, which is measured in kelvin. Thus, add channel type light
color temperature.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Link: https://lore.kernel.org/r/20230919081054.2050714-3-Basavaraj.Natikar@amd.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add IIO_DELTA_VELOCITY channel type

The delta velocity is defined as a piece-wise integration of
acceleration data. The delta velocity represents the linear velocity
change between two consecutive measurements and it
is measured in m / s (meters per second).

In order to track the total linear velocity change during a desired
period of time, simply sum-up the delta velocity samples acquired
during that time.

IIO currently does not offer a suitable channel type for this
type of measurements hence this patch adds it.

Signed-off-by: Ramona Bolboaca <ramona.bolboaca@analog.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230808075059.645525-3-ramona.bolboaca@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add IIO_DELTA_ANGL channel type

The delta angle is defined as a piece-wise integration of angular
velocity data. The delta angle represents the amount of
angular displacement between two consecutive measurements and it
is measured in radians.

In order to track the total angular displacement during a desired
period of time, simply sum-up the delta angle samples acquired
during that time.

IIO currently does not offer a suitable channel type for this
type of measurements hence this patch adds it.

Signed-off-by: Ramona Bolboaca <ramona.bolboaca@analog.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230808075059.645525-2-ramona.bolboaca@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Fix issues and style of the comments

The `scripts/kernel-doc -v -none -Wall` reports several issues
with the kernel doc in IIO core C file. Update the comments
accordingly.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20230724110204.46285-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Switch to krealloc_array()

Let the krealloc_array() copy the original data and
check for a multiplication overflow.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230724110204.46285-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Use sysfs_match_string() helper

Use sysfs_match_string() helper instead of open coded variant.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230724110204.46285-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Improve indentation in a few places

Improve an indentation in a few places to increase readability.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230721170022.3461-9-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Get rid of redundant 'else'

In the snippets like the following

if (...)
return / goto / break / continue ...;
else
...

the 'else' is redundant. Get rid of it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230721170022.3461-6-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Use min() instead of min_t() to make code more robust

min() has strict type checking and preferred over min_t() for
unsigned types to avoid overflow. Here it's unclear why min_t()
was chosen since both variables are of the same type. In any
case update to use min().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230721170022.3461-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Prevent invalid memory access when there is no parent

Commit 813665564b3d ("iio: core: Convert to use firmware node handle
instead of OF node") switched the kind of nodes to use for label
retrieval in device registration. Probably an unwanted change in that
commit was that if the device has no parent then NULL pointer is
accessed. This is what happens in the stock IIO dummy driver when a
new entry is created in configfs:

# mkdir /sys/kernel/config/iio/devices/dummy/foo
BUG: kernel NULL pointer dereference, address: ...
...
Call Trace:
__iio_device_register
iio_dummy_probe

Since there seems to be no reason to make a parent device of an IIO
dummy device mandatory, let’s prevent the invalid memory access in
__iio_device_register when the parent device is NULL. With this
change, the IIO dummy driver works fine with configfs.

Fixes: 813665564b3d ("iio: core: Convert to use firmware node handle instead of OF node")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
Link: https://lore.kernel.org/r/20230719083208.88149-1-mzamazal@redhat.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Sort headers

Sort the headers in alphabetic order in order to ease
the maintenance for this part.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230118074828.66155-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Replace iio_sysfs_match_string_with_gaps() by __sysfs_match_string()

None of the current users is using gaps in the list of the items.
No need to have a specific function for that, just replace it by
library available __sysfs_match_string().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230118074828.66155-1-andriy.shevchenko@linux.intel.com
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: add support for binary attributes

When a IIO device is registered, the IIO core creates an attribute group on
its own, where it puts the channel attributes, and where it copies the
attributes in indio_dev->info->attrs.

Unfortunately it doesn't take care of binary attributes (i.e. it only
consider indio_dev->info->attrs->attrs, and it ignores
indio_dev->info->attrs->bin_attrs).

Fix this by making the IIO layer take care also of the binary attributes.

Note that while it is necessary to copy the non-binary attributes because
the IIO layer needs more room to add the channels attribute, it should be
enough to assign the bin_attrs pointer to the binary attributes pointed by
indio_dev->info->attrs->bin_attrs.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220907132205.28021-8-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: add modifers for pitch, yaw, roll

Add modifiers for reporting rotations as euler angles (i.e. yaw, pitch and
roll).

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220907132205.28021-5-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: add modifiers for linear acceleration

Add IIO_MOD_LINEAR_X, IIO_MOD_LINEAR_Y and IIO_MOD_LINEAR_Z modifiers to te
IIO core, which is preparatory for adding the Bosch BNO055 IMU driver.

Bosch BNO055 IMU can report raw accelerations (among x, y and z axis) as
well as the so called "linear accelerations" (again, among x, y and z axis)
which is basically the acceleration after subtracting gravity and for which
those new modifiers are for.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220907132205.28021-2-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Use per-device lockdep class for mlock

If an IIO driver uses callbacks from another IIO driver and calls
iio_channel_start_all_cb() from one of its buffer setup ops, then
lockdep complains due to the lock nesting, as in the below example with
lmp91000.

Since the locks are being taken on different IIO devices, there is no
actual deadlock. Fix the warning by telling lockdep to use a different
class for each iio_device.

============================================
WARNING: possible recursive locking detected
--------------------------------------------
python3/23 is trying to acquire lock:
(&indio_dev->mlock){+.+.}-{3:3}, at: iio_update_buffers

but task is already holding lock:
(&indio_dev->mlock){+.+.}-{3:3}, at: enable_store

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&indio_dev->mlock);
lock(&indio_dev->mlock);

*** DEADLOCK ***

May be due to missing lock nesting notation

5 locks held by python3/23:
#0: (sb_writers#5){.+.+}-{0:0}, at: ksys_write
#1: (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter
#2: (kn->active#14){.+.+}-{0:0}, at: kernfs_fop_write_iter
#3: (&indio_dev->mlock){+.+.}-{3:3}, at: enable_store
#4: (&iio_dev_opaque->info_exist_lock){+.+.}-{3:3}, at: iio_update_buffers

Call Trace:
__mutex_lock
iio_update_buffers
iio_channel_start_all_cb
lmp91000_buffer_postenable
__iio_update_buffers
enable_store

Fixes: 67e17300dc1d76 ("iio: potentiostat: add LMP91000 support")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829091840.2791846-1-vincent.whitchurch@axis.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Avoid multiple line dereference for mask

Prefer lines > 80 characters over splitting dereferences across multiple
lines. Reported by checkpatch.pl.

Signed-off-by: Joe Simmons-Talbott <joetalbott@gmail.com>
Link: https://lore.kernel.org/r/20220819182012.219523-1-joetalbott@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Introduce _zeropoint for differential channels

Address an ABI gap for device where the offset of both lines in a
differential pair may be controlled so as to allow a wider range of
inputs, but without having any direct effect of the differential
measurement.

_offset cannot be used as to remain in line with existing usage,
userspace would be expected to apply it as (_raw + _offset) * _scale
whereas _zeropoint is not. i.e. If we were computing the differential
in software it would be.
((postive_raw + _zeropoint) - (negative_raw + zeropoint) + _offset) * _scale
= ((postive_raw - negative_raw) + _offset) * _scale
= (differential_raw + _offset) * _scale

Similarly calibbias is expected to tweak the measurement seen, not
the adjust the two lines of the differential pair.

Needed for in_capacitanceX-capacitanceY_zeropoint for the
AD7746 CDC driver.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220626122938.582107-12-jic23@kernel.org

iio: Add blank lines after declarations.

As reported by checkpatch.pl add blank lines after declarations.

Signed-off-by: Joe Simmons-Talbott <joetalbott@gmail.com>
Link: https://lore.kernel.org/r/20220727181855.589052-2-joetalbott@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: fix iio_format_avail_range() printing for none IIO_VAL_INT

iio_format_avail_range() should print range as follow [min, step, max], so
the function was previously calling iio_format_list() with length = 3,
length variable refers to the array size of values not the number of
elements. In case of non IIO_VAL_INT values each element has integer part
and decimal part. With length = 3 this would cause premature end of loop
and result in printing only one element.

Signed-off-by: Fawzi Khaber <fawzi.khaber@tdk.com>
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Fixes: eda20ba1e25e ("iio: core: Consolidate iio_format_avail_{list,range}()")
Link: https://lore.kernel.org/r/20220718130706.32571-1-jmaneyrol@invensense.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Don't use bare "unsigned"

Use "unsigned int" rather than bare "unsigned". Reported by checkpatch.pl.

Signed-off-by: Joe Simmons-Talbott <joetalbott@gmail.com>
Link: https://lore.kernel.org/r/20220624021806.1010962-1-joetalbott@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Use octal permissions and DEVICE_ATTR_{RO,RW}.

As reported by checkpatch.pl. Where possible use DEVICE_ATTR_RO(),
DEVICE_ATTR_RW(), and __ATTR_RO(). Change function names to be
<var>_show() for read and <var>_store() for write.

Suggested-by: Joe Perches <joe@perches.com>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Joe Simmons-Talbott <joetalbott@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220601185414.251571-1-joetalbott@gmail.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: Directly use ida_alloc()/free()

Use ida_alloc()/ida_free() instead of deprecated
ida_simple_get()/ida_simple_remove() .

Signed-off-by: keliu <liuke94@huawei.com>
Link: https://lore.kernel.org/r/20220527091739.2949426-1-liuke94@huawei.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Convert to use firmware node handle instead of OF node

Switch the IIO core to use firmware node handle instead of OF node.
This will allow to get label from firmware on non-OF systems.

Note, this doesn't change of_iio_*() APIs for now.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220413180202.19220-1-andriy.shevchenko@linux.intel.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: fix a few code style issues

* Fix indent in else statement
* Remove unnecessary 'else' after 'break'
* Remove space in '* attr'

Signed-off-by: Alexander Vorwerk <alexander.vorwerk@stud.uni-goettingen.de>
Link: https://lore.kernel.org/r/20220312180343.8935-1-alexander.vorwerk@stud.uni-goettingen.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Use sysfs_emit()

sysfs_emit() is preferred over raw s*printf() for sysfs attributes since it
knows about the sysfs buffer specifics and has some built-in checks for
size and alignment.

This patch converts the places in the IIO core that follow the pattern of

return s*printf(...)

to

return sysfs_emit(...)

This covers the new places that have been introduced where sprintf() is
used for formatting sysfs output since the last time this was done in
commit 83ca56b663cf ("iio: core: Use sysfs_emit() (trivial bits)").

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20211216185217.1054495-2-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: iio_device_alloc(): Remove unnecessary self drvdata

Drvdata is typically used by drivers to attach driver specific data to a
device. It is used to retrieve driver specific information when only the
device to which the data is attached is available.

In the IIO core in the `iio_device_alloc()` function we call
`iio_device_set_drvdata(indio_dev, indio_dev)`. This sets the drvdata of
the IIO device to itself.

This is rather unnecessary since if we have a pointer to the IIO device to
call `iio_device_get_drvdata()` on it we don't need to call the function
since we already have the pointer. If we only have a pointer to the `struct
device` we can use `dev_to_iio_dev()` to get the IIO device from it.

Furthermore the drvdata is supposed to be reserved for drivers, so it
should not be used by the IIO core in the first place.

The `set_drvdata()` has been around from the very beginning of the IIO
framework and back then it was used in the IIO device sysfs attribute
handling code. But that was subsequently replaced with a `dev_to_iio_dev()`
in commit e53f5ac52ec1 ("iio: Use dev_to_iio_dev()") and other cleanups.

The self `set_drvdata()` is now no longer needed and can be removed.

Verified that there no longer any users by checking for potential users
using the following two coccinelle scripts and reviewing that none of the
matches are problematic code.

<smpl>
@@
struct iio_dev *iio_dev;
expression dev;
identifier fn !~ "(remove|resume|suspend)";
@@
fn(...)
{
...
*iio_dev = dev_get_drvdata(dev)
...
}
</smpl>

<smpl>
@r1@
position p;
struct iio_dev *indio_dev;
identifier dev_fn =~ "^dev_";
identifier devm_fn =~ "^devm_";
@@
(
dev_fn
|
devm_fn
)
(&indio_dev@p->dev, ...)

@@
struct iio_dev *indio_dev;
position p != r1.p;
@@
*&indio_dev@p->dev</smpl>

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

iio: Mark iio_device_type as const

The iio_device_type struct is never modified, mark it as const. This allows
it to be placed in a read-only memory section, which will protect against
accidental or deliberate modification.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20211031080421.2086-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Introduce IIO_VAL_INT_64.

Introduce IIO_VAL_INT_64 to read 64-bit value for
channel attribute. Val is used as lower 32 bits.

Signed-off-by: Andriy Tryshnivskyy <andriy.tryshnivskyy@opensynergy.com>
Link: https://lore.kernel.org/r/20211024091627.28031-2-andriy.tryshnivskyy@opensynergy.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add output buffer support

Currently IIO only supports buffer mode for capture devices like ADCs. Add
support for buffered mode for output devices like DACs.

The output buffer implementation is analogous to the input buffer
implementation. Instead of using read() to get data from the buffer write()
is used to copy data into the buffer.

poll() with POLLOUT will wakeup if there is space available.

Drivers can remove data from a buffer using iio_pop_from_buffer(), the
function can e.g. called from a trigger handler to write the data to
hardware.

A buffer can only be either a output buffer or an input, but not both. So,
for a device that has an ADC and DAC path, this will mean 2 IIO buffers
(one for each direction).

The direction of the buffer is decided by the new direction field of the
iio_buffer struct and should be set after allocating and before registering
it.

Co-developed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Co-developed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Mihail Chindris <mihail.chindris@analog.com>
Link: https://lore.kernel.org/r/20211007080035.2531-2-mihail.chindris@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: fix double free in iio_device_unregister_sysfs()

I got the double free report:

BUG: KASAN: double-free or invalid-free in kfree+0xce/0x390
iio_device_unregister_sysfs+0x108/0x13b [industrialio]
iio_dev_release+0x9e/0x10e [industrialio]
device_release+0xa5/0x240

If __iio_device_register() fails, iio_dev_opaque->groups will be freed
in error path in iio_device_unregister_sysfs(), then iio_dev_release()
will call iio_device_unregister_sysfs() again, it causes double free.
Set iio_dev_opaque->groups to NULL when it's freed to fix this double free.

Not this is a local work around for a more general mess around life time
management that will get cleaned up and should make this handling
unnecesarry.

Fixes: 32f171724e5c ("iio: core: rework iio device group creation")
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20211013030532.956133-1-yangyingliang@huawei.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: check return value when calling dev_set_name()

I got a null-ptr-deref report when doing fault injection test:

BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:strlen+0x0/0x20
Call Trace:
start_creating+0x199/0x2f0
debugfs_create_dir+0x25/0x430
__iio_device_register+0x4da/0x1b40 [industrialio]
__devm_iio_device_register+0x22/0x80 [industrialio]
max1027_probe+0x639/0x860 [max1027]
spi_probe+0x183/0x210
really_probe+0x285/0xc30

If dev_set_name() fails, the dev_name() is null, check the return
value of dev_set_name() to avoid the null-ptr-deref.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: e553f182d55b ("staging: iio: core: Introduce debugfs support...")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211012063624.3167460-1-yangyingliang@huawei.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Support reading extended name as label

The point of this new change is to make the IIO tree actually parsable.

Before, given this attribute as a filename:
in_voltage0_aux_sample_rate

Userspace had no way to know if the attribute name was
"aux_sample_rate" with no extended name, or "sample_rate" with "aux" as
the extended name, or just "rate" with "aux_sample" as the extended
name.

This was somewhat possible to deduce when there was more than one
attribute present for a given channel, e.g:
in_voltage0_aux_sample_rate
in_voltage0_aux_frequency

There, it was possible to deduce that "aux" was the extended name. But
even with more than one attribute, this wasn't very robust, as two
attributes starting with the same prefix (e.g. "sample_rate" and
"sample_size") would result in the first part of the prefix being
interpreted as being part of the extended name.

To address the issue, knowing that channels will never have both a label
and an extended name, set the channel's label to the extended name.
In this case, the label's attribute will also have the extended name in
its filename, but we can live with that - userspace can open
in_voltage0_<prefix>_label and verify that it returns <prefix> to obtain
the extended name.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20210618123005.49867-3-paul@crapouillou.net
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Forbid use of both labels and extended names

Extended names are a problem for user-space as they make the filenames
in sysfs sometimes not parsable. They are now deprecated in favor of
labels.

This change makes sure that a device driver won't provide both labels
and extended names for its channels. It has never been the case and we
don't want it to happen.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210618123005.49867-2-paul@crapouillou.net
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: Fix an error pointer vs NULL bug in devm_iio_device_alloc()

The devm_iio_device_alloc() function is supposed to return NULL and not
error pointers. Returning an error pointer will lead to a crash in the
callers.

Fixes: cf5724e91515 ("iio: core: simplify some devm functions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/YJ+a1yaMu2QNATgt@mwanda
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 @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: core: simplify some devm functions

Use devm_add_action_or_reset() instead of devres_alloc() and
devres_add(), which works the same. This will simplify the
code. There is no functional changes.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/1617881896-3164-6-git-send-email-yangyicong@hisilicon.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: return ENODEV if ioctl is unknown

When the ioctl() mechanism was introduced in IIO core to centralize the
registration of all ioctls in one place via commit 8dedcc3eee3ac ("iio:
core: centralize ioctl() calls to the main chardev"), the return code was
changed from ENODEV to EINVAL, when the ioctl code isn't known.

This was done by accident.

This change reverts back to the old behavior, where if the ioctl() code
isn't known, ENODEV is returned (vs EINVAL).

This was brought into perspective by this patch:
https://lore.kernel.org/linux-iio/20210428150815.136150-1-paul@crapouillou.net/

Fixes: 8dedcc3eee3ac ("iio: core: centralize ioctl() calls to the main chardev")
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: fix ioctl handlers removal

Currently ioctl handlers are removed twice. For the first time during
iio_device_unregister() then later on inside
iio_device_unregister_eventset() and iio_buffers_free_sysfs_and_mask().
Double free leads to kernel panic.

Fix this by not touching ioctl handlers list directly but rather
letting code responsible for registration call the matching cleanup
routine itself.

Fixes: 8dedcc3eee3ac ("iio: core: centralize ioctl() calls to the main chardev")
Signed-off-by: Tomasz Duszynski <tomasz.duszynski@octakon.com>
Acked-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210423080244.2790-1-tomasz.duszynski@octakon.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: __iio_format_value(): Convert to sysfs_emit_at()

sysfs_emit() is preferred over raw s*printf() for sysfs attributes since it
knows about the sysfs buffer specifics and has some built-in sanity checks.

Convert __iio_format_value() and related functions to use this new
interface.

This conversion involves changing the signature of __iio_format_value() so
that it similar to sysfs_emit_at() and takes the buffers start address and
an offset where to write within the buffer.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20210320071405.9347-4-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: iio_enum_available_read(): Convert to sysfs_emit_at()

sysfs_emit() is preferred over raw s*printf() for sysfs attributes since it
knows about the sysfs buffer specifics and has some built-in sanity checks.

Convert the iio_enum_available_read() function to use sysfs_emit_at()
instead of scnprintf().

The conversion is straight forward, the only difference is that
sysfs_emit_at() takes the buffers start address and an offset as parameters
and already knows about the buffer's size limit.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20210320071405.9347-3-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Use sysfs_emit() (trivial bits)

sysfs_emit() is preferred over raw s*printf() for sysfs attributes since it
knows about the sysfs buffer specifics and has some built-in sanity checks.

This patch converts the places in the iio core that follow the pattern of

return s*printf(...)

to

return sysfs_emit(...)

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20210320071405.9347-2-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: buffer: fix use-after-free for attached_buffers array

Thanks to Lars for finding this.
The free of the 'attached_buffers' array should be done as late as
possible. This change moves it to iio_buffers_put(), which looks like
the best place for it, since it takes place right before the IIO device
data is free'd.
The free of this array will be handled by calling iio_device_free().
The iio_buffers_put() function is renamed to iio_device_detach_buffers()
since the role of this function changes a bit.

It looks like this issue was ocurring on the error path of
iio_buffers_alloc_sysfs_and_mask() and in
iio_buffers_free_sysfs_and_mask()

Added a comment in the doc-header of iio_device_attach_buffer() to
mention how this will be free'd in case anyone is reading the code
and becoming confused about it.

Fixes: ee708e6baacd ("iio: buffer: introduce support for attaching more IIO buffers")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210307185444.32924-1-ardeleanalex@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add relative sensitivity support

Some hid sensors may use relative sensitivity such as als sensor.
This patch adds relative sensitivity checking for all hid sensors.

Signed-off-by: Ye Xiang <xiang.ye@intel.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Link: https://lore.kernel.org/r/20210207070048.23935-2-xiang.ye@intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: use getter/setter functions

Use getter and setter functions, for a variety of data types.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Link: https://lore.kernel.org/r/20210209211315.1261791-1-Julia.Lawall@inria.fr
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: rename 'dev' -> 'indio_dev' in iio_device_alloc()

The 'dev' variable name usually refers to 'struct device' types. However in
iio_device_alloc() this was used for the 'struct iio_dev' type, which was
sometimes causing minor confusions.

This change renames the variable to 'indio_dev', which is the usual name
used around IIO for 'struct iio_dev' type objects.
It makes grepping a bit easier as well.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210215104043.91251-22-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: buffer: introduce support for attaching more IIO buffers

With this change, calling iio_device_attach_buffer() will actually attach
more buffers.
Right now this doesn't do any validation of whether a buffer is attached
twice; maybe that can be added later (if needed). Attaching a buffer more
than once should yield noticeably bad results.

The first buffer is the legacy buffer, so a reference is kept to it.

At this point, accessing the data for the extra buffers (that are added
after the first one) isn't possible yet.

The iio_device_attach_buffer() is also changed to return an error code,
which for now is -ENOMEM if the array could not be realloc-ed for more
buffers.
To adapt to this new change iio_device_attach_buffer() is called last in
all place where it's called. The realloc failure is a bit difficult to
handle during un-managed calls when unwinding, so it's better to have this
as the last error in the setup_buffer calls.

At this point, no driver should call iio_device_attach_buffer() directly,
it should call one of the {devm_}iio_triggered_buffer_setup() or
devm_iio_kfifo_buffer_setup() or devm_iio_dmaengine_buffer_setup()
functions. This makes iio_device_attach_buffer() a bit easier to handle.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210215104043.91251-20-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: wrap iio device & buffer into struct for character devices

In order to keep backwards compatibility with the current chardev
mechanism, and in order to add support for multiple buffers per IIO device,
we need to pass both the IIO device & IIO buffer to the chardev.

This is particularly needed for the iio_buffer_read_outer() function, where
we need to pass another buffer object than 'indio_dev->buffer'.

Since we'll also open some chardevs via anon inodes, we can pass extra
buffers in that function by assigning another object to the
iio_dev_buffer_pair object.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210215104043.91251-17-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: buffer: wrap all buffer attributes into iio_dev_attr

This change wraps all buffer attributes into iio_dev_attr objects, and
assigns a reference to the IIO buffer they belong to.

With the addition of multiple IIO buffers per one IIO device, we need a way
to know which IIO buffer is being enabled/disabled/controlled.

We know that all buffer attributes are device_attributes. So we can wrap
them with a iio_dev_attr types. In the iio_dev_attr type, we can also hold
a reference to an IIO buffer.
So, we end up being able to allocate wrapped attributes for all buffer
attributes (even the one from other drivers).

The neat part with this mechanism, is that we don't need to add any extra
cleanup, because these attributes are being added to a dynamic list that
will get cleaned up via iio_free_chan_devattr_list().

With this change, the 'buffer->scan_el_dev_attr_list' list is being renamed
to 'buffer->buffer_attr_list', effectively merging (or finalizing the
merge) of the buffer/ & scan_elements/ attributes internally.

Accessing these new buffer attributes can now be done via
'to_iio_dev_attr(attr)->buffer' inside the show/store handlers.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210215104043.91251-15-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: add reference to iio buffer on iio_dev_attr

This change adds a reference to a 'struct iio_buffer' object on the
iio_dev_attr object. This way, we can use the created iio_dev_attr objects
on per-buffer basis (since they're allocated anyway).

A minor downside of this change is that the number of parameters on
__iio_add_chan_devattr() grows by 1. This looks like it could do with a bit
of a re-think.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210215104043.91251-14-alexandru.ardelean@analog.com
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: register chardev only if needed

We only need a chardev if we need to support buffers and/or events.

With this change, a chardev will be created only if an IIO buffer is
attached OR an event_interface is configured.

Otherwise, no chardev will be created, and the IIO device will get
registered with the 'device_add()' call.

Quite a lot of IIO devices don't really need a chardev, so this is a minor
improvement to the IIO core, as the IIO device will take up (slightly)
fewer resources.

In order to not create a chardev, we mostly just need to not initialize the
indio_dev->dev.devt field. If that is un-initialized, cdev_device_add()
behaves like device_add().

This change has a small chance of breaking some userspace ABI, because it
removes un-needed chardevs. While these chardevs (that are being removed)
have always been unusable, it is likely that some scripts may check their
existence (for whatever logic).
And we also hope that before opening these chardevs, userspace would have
already checked for some pre-conditions to make sure that opening these
chardevs makes sense.
For the most part, there is also the hope that it would be easier to change
userspace code than revert this. But in the case that reverting this is
required, it should be easy enough to do it.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210215104043.91251-9-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: iio_format_value(): Fix IIO_VAL_FRACTIONAL_LOG2 values between -1.0 and 0.0

When formatting a value using IIO_VAL_FRACTIONAL_LOG2 and the values is
between -1 and 0 the sign is omitted.

We need the same trick as for IIO_VAL_FRACTIONAL to make sure this gets
formatted correctly.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20201215191743.2725-2-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: iio_format_value(): Use signed temporary for IIO_VAL_FRACTIONAL_LOG2

IIO_VAL_FRACTIONAL_LOG2 works with signed values, yet the temporary we use
is unsigned. This works at the moment because the variable is implicitly
cast to signed everywhere where it is used.

But it will certainly be cleaner to use a signed variable in the first
place.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20201215191743.2725-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Allow drivers to specify a label without it coming from of

Only set indio_dev->label from of/dt if there actually is a label
specified in of.

This allows drivers to set a label without this being overwritten with
NULL when there is no label specified in of. This is esp. useful on
devices where of is not used at all, such as your typical x86/ACPI device.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210207160901.110643-2-hdegoede@redhat.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Handle enumerated properties with gaps

Some enums might have gaps or reserved values in the middle of their value
range. E.g. consider a 2-bit enum where the values 0, 1 and 3 have a
meaning, but 2 is a reserved value and can not be used.

Add support for such enums to the IIO enum helper functions. A reserved
values is marked by setting its entry in the items array to NULL rather
than the normal descriptive string value.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210107112049.10815-1-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Copy iio_info.attrs->is_visible into iio_dev_opaque.chan_attr_group.is_visible

The iio-core extends the attr_group provided by the driver with its
own attributes. To be able to do this it:

1. Has its own (non const) io_dev_opaque.chan_attr_group attr_group struct
2. It allocates a new attrs array with room for both the drivers and its
own attributes
3. It copies over the driver provided attributes into the newly allocated
attrs array.

But the drivers attr_group may contain more then just the attrs array, it
may also contain an is_visible callback and at least the adi-axi-adc.c
is currently defining such a callback.

Change the attr_group copying code to also copy over the is_visible
callback, so that drivers can define one and have it workins as is
normal for attr_group-s all over the kernel.

Note that the is_visible callback takes an index into the array as
argument, so that indices of the driver's attributes must not change,
this is not a problem as the driver's own attributes are added first
to the newly allocated attrs array and the attributes handled by the
core are appended after the driver's attributes.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Link: https://lore.kernel.org/r/20201125084606.11404-2-hdegoede@redhat.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Simplify iio_format_list()

iio_format_list() has two branches in a switch statement that are almost
identical. They only differ in the stride that is used to iterate through
the item list.

Consolidate this into a common code path to simplify the code.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20201114120000.6533-2-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Consolidate iio_format_avail_{list,range}()

The iio_format_avail_list() and iio_format_avail_range() functions are
almost identical. The only differences are that iio_format_avail_range()
expects a fixed amount of items and adds brackets "[ ]" around the output.

Refactor them into a common helper function. This improves the
maintainability of the code as it makes it easier to modify the
implementation of these functions.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20201114120000.6533-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: return -EINVAL when no ioctl handler has been run

It seems that when this was tested the happy case was more tested. A few of
the userspace apps rely on this returning negative error codes in case an
ioctl() is not available.

When running multiple ioctl() handlers or when calling an ioctl() that
doesn't exist, IIO_IOCTL_UNHANDLED is returned. In that case -EINVAL should
be returned.

Fixes: 8dedcc3eee3a ("iio: core: centralize ioctl() calls to the main chardev")
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201117095154.7189-1-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: organize buffer file-ops in the order defined in the struct

The change is mostly cosmetic. This organizes the order of assignment of
the members of 'iio_buffer_fileops' to be similar to the one as defined in
the 'struct file_operations' type.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201117103753.8450-1-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: centralize ioctl() calls to the main chardev

The aim of this is to improve a bit the organization of ioctl() calls in
IIO core. Currently the chardev is split across IIO core sub-modules/files.
The main chardev has to be able to handle ioctl() calls, and if we need to
add buffer ioctl() calls, this would complicate things.

The 'industrialio-core.c' file will provide a 'iio_device_ioctl()' which
will iterate over a list of ioctls registered with the IIO device. These
can be event ioctl() or buffer ioctl() calls, or something else.

Each ioctl() handler will have to return a IIO_IOCTL_UNHANDLED code (which
is positive 1), if the ioctl() did not handle the call in any. This
eliminates any potential ambiguities about negative error codes, which
should fail the call altogether.

If any ioctl() returns 0, it was considered that it was serviced
successfully and the loop will exit.

This change also moves the handling of the IIO_GET_EVENT_FD_IOCTL command
inside 'industrialio-event.c', where this is better suited.

This patch is a combination of 2 other patches from an older series:
Patch 1: iio: core: add simple centralized mechanism for ioctl() handlers
Link: https://lore.kernel.org/linux-iio/20200427131100.50845-6-alexandru.ardelean@analog.com/
Patch 2: iio: core: use new common ioctl() mechanism
Link: https://lore.kernel.org/linux-iio/20200427131100.50845-7-alexandru.ardelean@analog.com/

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20200924084155.99406-1-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: core: Fix IIO_VAL_FRACTIONAL calculation for negative values

Fixes IIO_VAL_FRACTIONAL for case when the result is negative and
exponent is 0.

example: if the result is -0.75, tmp0 will be 0 and tmp1 = 75
This causes the output to lose sign because of %d in snprintf
which works for tmp0 <= -1.

Reported-by: kernel test robot <lkp@intel.com> #error: uninitialized symbol tmp
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com>
Link: https://lore.kernel.org/r/1601910316-24111-1-git-send-email-anand.ashok.dumbre@xilinx.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:core: Tidy up kernel-doc.

One comment isn't kernel-doc at all, but starts with /** and another
is simply missing a parameter that was introduced recently.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200913132115.800131-4-jic23@kernel.org

iio: temperature: mlx90632: Interface to change object ambient temperature

Since object temperature might be different than the sensor temperature
the infrared sensors should provide an interface to inject ambient
temperature. This was in past done via write to ambient temperature
interface (in_temp_ambient_raw), but I think most people did not know
about it. This solution introduces a new iio type of the CALIBAMBIENT
which is hopefully more descriptive and more explicit about the purpose
and capabilities of the sensors.

Signed-off-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200906210231.383976-1-cmo@melexis.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

iio: add IIO_MOD_O2 modifier

Add modifier IIO_MOD_O2 for O2 concentration reporting

Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: fix/re-introduce back parent assignment

This was introduced initially via commit 78289b4a58b58 ("iio: core: pass
parent device as parameter during allocation"), but was accidentally
removed via commit 6d4ebd565d15f ("iio: core: wrap IIO device into an
iio_dev_opaque object").

This looks like a rebase gone wrong, and ends up breaking devicetree
bindings of IIO clients.

This change adds back the parent assignment.

Fixes 6d4ebd565d15f: ("iio: core: wrap IIO device into an iio_dev_opaque object")
Reported-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Tested-by: Dmitry Baryshkov <dbaryshkov@gmail.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: remove padding from private information

There was a recent discussion about this code:
https://lore.kernel.org/linux-iio/20200322165317.0b1f0674@archlinux/

This looks like a good time to removed this, since any issues about it
should pop-up under testing, because the iio_dev is having a bit of an
overhaul and stuff being moved to iio_dev_opaque.

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 missing IIO_MOD_H2/ETHANOL string identifiers

Add missing strings to iio_modifier_names[] for proper modification
of channels.

Fixes: b170f7d48443d (iio: Add modifiers for ethanol and H2 gases)
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Cc: <Stable@vger.kernel.org>
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: Use an early return in iio_device_alloc to simplify code.

Noticed whilst reviewing Alexandru's patch to the same function.
If we simply flip the logic and return NULL immediately after memory
allocation failure we reduce the indent of the following block and
end up with more 'idiomatic' kernel code.

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

iio: core: Fix handling of 'dB'

This patch fixes the call to iio_str_to_fixpoint when using 'dB' sufix.
Before this the scale_db was not used when parsing the string written to
the attribute and it failed with invalid value.

Fixes: b8528224741b ("iio: core: Handle 'dB' suffix in core")
Signed-off-by: Mircea Caprioru <mircea.caprioru@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: move 'indio_dev->info' null check first in __iio_device_register()

Moves this to be the first check, as it's very simple and fails the
registration earlier, instead of potentially initializing the
'indio_dev->label' and checking for duplicate indexes, and then failing
with this simple-check.

This is a minor optimization, since '__iio_device_register()' will waste
fewer validation cycles in case 'indio_dev->info' is NULL.

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: Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit. Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
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: Handle 'dB' suffix in core

This patch handles the db suffix used for writing micro db values.

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: buffer: rename 'read_first_n' callback to 'read'

It is implied that 'read' will read the first n bytes and not e.g. bytes
only from offsets within the buffer that are a prime number.

This change is non-functional, mostly just a rename.
A secondary intent with this patch is to make room later to add a write
callback.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: add thermocouple_type standard attribute

We have a couple of thermocouple IIO drivers, supporting several chips.
Some of them support only one specific thermocouple type (e.g. "K", "J"),
one of them can be configured to work with several different thermocouple
types.

In certain applications thermocouples could be externally connected to the
chip by the user.

This patch introduces a new IIO standard attribute to report the supported
thermocouple type and, where applicable, to allow it to be dynamically set
using sysfs.

Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Cc: Matt Weber <matthew.weber@rockwellcollins.com>
Cc: Matt Ranostay <matt.ranostay@konsulko.com>
Cc: Chuhong Yuan <hslester96@gmail.com>
Cc: Daniel Gomez <dagmcr@gmail.com>
Cc: linux-iio@vger.kernel.org
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: add char type for sysfs attributes

This patch introduces IIO_VAL_CHAR type for standard IIO attributes to
allow for attributes that needs to be represented by character rather
than a number. This is preparatory for introducing a new attribute whose
purpose is to describe thermocouple type, that can be i.e. "J", "K", etc..

The char-type value is stored in the first "value" integer that is passed
to the .[read/write]_raw() callbacks.

Note that in order to make it possible for the IIO core to correctly parse
this type (actually, to avoid integer parsing), it became mandatory for
any driver that wish to use IIO_VAL_CHAR on a writable attribute to
implement .write_raw_get_fmt().

Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Cc: Matt Weber <matthew.weber@rockwellcollins.com>
Cc: Matt Ranostay <matt.ranostay@konsulko.com>
Cc: Chuhong Yuan <hslester96@gmail.com>
Cc: Daniel Gomez <dagmcr@gmail.com>
Cc: linux-iio@vger.kernel.org
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

compat_ioctl: move more drivers to compat_ptr_ioctl

The .ioctl and .compat_ioctl file operations have the same prototype so
they can both point to the same function, which works great almost all
the time when all the commands are compatible.

One exception is the s390 architecture, where a compat pointer is only
31 bit wide, and converting it into a 64-bit pointer requires calling
compat_ptr(). Most drivers here will never run in s390, but since we now
have a generic helper for it, it's easy enough to use it consistently.

I double-checked all these drivers to ensure that all ioctl arguments
are used as pointers or are ignored, but are not interpreted as integer
values.

Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: Darren Hart (VMware) <dvhart@infradead.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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>

timekeeping: Use proper clock specifier names in functions

This makes boot uniformly boottime and tai uniformly clocktai, to
address the remaining oversights.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lkml.kernel.org/r/20190621203249.3909-2-Jason@zx2c4.com

iio: core: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: linux-iio@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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:core: Fix bug in length of event info_mask and catch unhandled bits set in masks.

The incorrect limit for the for_each_set_bit loop was noticed whilst fixing
this other case. Note that as we only have 3 possible entries a the moment
and the value was set to 4, the bug would not have any effect currently.
It will bite fairly soon though, so best fix it now.

See commit ef4b4856593f ("iio:core: Fix bug in length of event info_mask and
catch unhandled bits set in masks.") for details.

Signed-off-by: Young Xiao <92siuyang@gmail.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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: core: fix a possible circular locking dependency

This fixes a possible circular locking dependency detected warning seen
with:
- CONFIG_PROVE_LOCKING=y
- consumer/provider IIO devices (ex: "voltage-divider" consumer of "adc")

When using the IIO consumer interface, e.g. iio_channel_get(), the consumer
device will likely call iio_read_channel_raw() or similar that rely on
'info_exist_lock' mutex.

typically:
...
mutex_lock(&chan->indio_dev->info_exist_lock);
if (chan->indio_dev->info == NULL) {
ret = -ENODEV;
goto err_unlock;
}
ret = do_some_ops()
err_unlock:
mutex_unlock(&chan->indio_dev->info_exist_lock);
return ret;
...

Same mutex is also hold in iio_device_unregister().

The following deadlock warning happens when:
- the consumer device has called an API like iio_read_channel_raw()
at least once.
- the consumer driver is unregistered, removed (unbind from sysfs)

======================================================
WARNING: possible circular locking dependency detected
4.19.24 #577 Not tainted
------------------------------------------------------
sh/372 is trying to acquire lock:
(kn->count#30){++++}, at: kernfs_remove_by_name_ns+0x3c/0x84

but task is already holding lock:
(&dev->info_exist_lock){+.+.}, at: iio_device_unregister+0x18/0x60

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&dev->info_exist_lock){+.+.}:
__mutex_lock+0x70/0xa3c
mutex_lock_nested+0x1c/0x24
iio_read_channel_raw+0x1c/0x60
iio_read_channel_info+0xa8/0xb0
dev_attr_show+0x1c/0x48
sysfs_kf_seq_show+0x84/0xec
seq_read+0x154/0x528
__vfs_read+0x2c/0x15c
vfs_read+0x8c/0x110
ksys_read+0x4c/0xac
ret_fast_syscall+0x0/0x28
0xbedefb60

-> #0 (kn->count#30){++++}:
lock_acquire+0xd8/0x268
__kernfs_remove+0x288/0x374
kernfs_remove_by_name_ns+0x3c/0x84
remove_files+0x34/0x78
sysfs_remove_group+0x40/0x9c
sysfs_remove_groups+0x24/0x34
device_remove_attrs+0x38/0x64
device_del+0x11c/0x360
cdev_device_del+0x14/0x2c
iio_device_unregister+0x24/0x60
release_nodes+0x1bc/0x200
device_release_driver_internal+0x1a0/0x230
unbind_store+0x80/0x130
kernfs_fop_write+0x100/0x1e4
__vfs_write+0x2c/0x160
vfs_write+0xa4/0x17c
ksys_write+0x4c/0xac
ret_fast_syscall+0x0/0x28
0xbe906840

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&dev->info_exist_lock);
lock(kn->count#30);
lock(&dev->info_exist_lock);
lock(kn->count#30);

*** DEADLOCK ***
...

cdev_device_del() can be called without holding the lock. It should be safe
as info_exist_lock prevents kernelspace consumers to use the exported
routines during/after provider removal. cdev_device_del() is for userspace.

Help to reproduce:
See example: Documentation/devicetree/bindings/iio/afe/voltage-divider.txt
sysv {
compatible = "voltage-divider";
io-channels = <&adc 0>;
output-ohms = <22>;
full-ohms = <222>;
};

First, go to iio:deviceX for the "voltage-divider", do one read:
$ cd /sys/bus/iio/devices/iio:deviceX
$ cat in_voltage0_raw

Then, unbind the consumer driver. It triggers above deadlock warning.
$ cd /sys/bus/platform/drivers/iio-rescale/
$ echo sysv > unbind

Note I don't actually expect stable will pick this up all the
way back into IIO being in staging, but if's probably valid that
far back.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Fixes: ac917a81117c ("staging:iio:core set the iio_dev.info pointer to null on unregister")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: add IIO_MASSCONCENTRATION channel type

Measuring particulate matter in ug / m3 (micro-grams per cubic meter)
is de facto standard. Existing air quality sensors usually follow
this convention and are capable of returning measurements using
this unit.

IIO currently does not offer suitable channel type for this
type of measurements hence this patch adds this.

In addition, extra modifiers are introduced used for distinguishing
between fine pm1, pm2p5 and coarse pm4, pm10 particle measurements, i.e
IIO_MOD_PM1, IIO_MOD_PM25 and IIO_MOD_PM4, IIO_MOD_PM10.

pmX consists of particles with aerodynamic diameter less or equal to
X micrometers.

Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
Acked-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: check 'info' value before registering the device

When the 'info' structure inside indio_dev is left uninitialized,
a segmentation fault occurs.

Check the 'info' value before using it and if it is equal to
NULL, return with -EINVAL.

Signed-off-by: Andi Shyti <andi@etezian.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add modifier for DUV light

Signed-off-by: Maxime Roussin-Bélanger <maxime.roussinbelanger@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add channel for Phase

Add new channel type support for phase.

This channel may be used by Time-of-flight sensors to express the
phase difference between emitted and received signals. Those sensor
will then use the phase shift of return signals to approximate the
distance to objects.

Signed-off-by: Mathieu Othacehe <m.othacehe@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: use timespec64 based interfaces for iio_get_time_ns()

We have replacements for all the deprecated timespec based interfaces now,
so this can finally convert iio_get_time_ns() to consistently use the
nanosecond or timespec64 based interfaces instead, avoiding the y2038
overflow.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add channel for Position Relative

Add new channel type for relative position on a pad.

These type of analog sensor offers the position of a pen
on a touchpad, and is represented as a voltage, which can be
converted to a position on X and Y axis on the pad.
The channel will hand the relative position on the pad in both directions.

The channel can then be consumed by a touchscreen driver or
read as-is for a raw indication of the touchpen on a touchpad.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: fix kernel-doc build errors

Fix build errors in kernel-doc notation. Symbols that end in '_'
have a special meaning, but adding a '*' makes them OK.

../drivers/iio/industrialio-core.c:635: ERROR: Unknown target name: "iio_val".
../drivers/iio/industrialio-core.c:642: ERROR: Unknown target name: "iio_val".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 1397962
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: Return error for failed read_reg

If an IIO device returns an error code for a read access via debugfs, it
is currently ignored by the IIO core (other than emitting an error
message). Instead, return this error code to user space, so upper layers
can detect it correctly.

Signed-off-by: Matt Fornero <matt.fornero@mathworks.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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>

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: core: Use __sysfs_match_string() helper

Use __sysfs_match_string() helper instead of open coded variant.

Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Fix suspicious sizeof usage

Pointer size is variours in different system, say 32bit for 4 and 64bit
for 8. The 'sizeof(infomask)' may lead to wrong bit numbers.

Signed-off-by: Orson Zhai <orson.zhai@spreadtrum.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Fix IIO_VAL_FRACTIONAL_LOG2 for negative values

Fix formatting of negative values of type IIO_VAL_FRACTIONAL_LOG2 by
switching from do_div(), which can't handle negative numbers, to
div_s64_rem(). Also use shift_right for shifting, which is safe with
negative values.

Signed-off-by: Nikolaus Schulz <nikolaus.schulz@avionic-design.de>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:core: utilize new cdev_device_add helper function

Replace the open coded registration of the cdev and dev with the
new device_add_cdev() helper. The helper replaces a common pattern by
taking the proper reference against the parent device and adding both
the cdev and the device.

In doing so we have to remove a guard statement from cdev_del,
but this doesn't appear to be required in any way.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio:buffer.h - split into buffer.h and buffer_impl.h

buffer.h supplies everything needed for devices using buffers.
buffer_impl.h supplies access to the internals as needed to write
a buffer implementation.

This was really motivated by the mess that turned up in the
kernel-doc documentation pulled in by the new sphinx docs.
It made it clear that our logical separations in headers were
generally terrible. The buffer case was easy to sort out without
greatly effecting drivers so here it is.

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

iio: Add channel for Gravity

Add new channel types support for gravity sensor.

Gravity sensor provides an application-level or physical collection that
identifies a device that measures exclusively the force of Earth's
gravity along any number of axes.

More information can be found in:
http://www.usb.org/developers/hidpage/HUTRR59_-_Usages_for_Wearables.pdf

Signed-off-by: Song Hongyan <hongyan.song@intel.com>
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: Implement counter channel type and info constants

Quadrature encoders, such as rotary encoders and linear encoders, are
devices which are capable of encoding the relative position and
direction of motion of a shaft. This patch introduces several IIO
constants for supporting quadrature encoder counter devices.

IIO_COUNT: Current count (main data provided by the counter device)
IIO_INDEX: Counter device index value

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

iio:core: fix IIO_VAL_FRACTIONAL sign handling

7985e7c100 ("iio: Introduce a new fractional value type") introduced a
new IIO_VAL_FRACTIONAL value type meant to represent rational type numbers
expressed by a numerator and denominator combination.

Formating of IIO_VAL_FRACTIONAL values relies upon do_div() usage. This
fails handling negative values properly since parameters are reevaluated
as unsigned values.
Fix this by using div_s64_rem() instead. Computed integer part will carry
properly signed value. Formatted fractional part will always be positive.

Fixes: 7985e7c100 ("iio: Introduce a new fractional value type")
Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
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: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: electricalconductivity: add IIO_ELECTRICALCONDUCTIVITY type

Signed-off-by: Matt Ranostay <mranostay@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: Add channel for UV index

UV index indicating strength of sunburn-producing ultraviolet (UV) radiation

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

iio: Add modifier for UV light

Signed-off-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
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: ph: add IIO_PH channel type

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

include/linux/kernel.h: change abs() macro so it uses consistent return type

Rewrite abs() so that its return type does not depend on the
architecture and no unexpected type conversion happen inside of it. The
only conversion is from unsigned to signed type. char is left as a
return type but treated as a signed type regradless of it's actual
signedness.

With the old version, int arguments were promoted to long and depending
on architecture a long argument might result in s64 or long return type
(which may or may not be the same).

This came after some back and forth with Nicolas. The current macro has
different return type (for the same input type) depending on
architecture which might be midly iritating.

An alternative version would promote to int like so:

#define abs(x) __abs_choose_expr(x, long long, \
__abs_choose_expr(x, long, \
__builtin_choose_expr( \
sizeof(x) <= sizeof(int), \
({ int __x = (x); __x<0?-__x:__x; }), \
((void)0))))

I have no preference but imagine Linus might. :] Nicolas argument against
is that promoting to int causes iconsistent behaviour:

int main(void) {
unsigned short a = 0, b = 1, c = a - b;
unsigned short d = abs(a - b);
unsigned short e = abs(c);
printf("%u %u\n", d, e); // prints: 1 65535
}

Then again, no sane person expects consistent behaviour from C integer
arithmetic. ;)

Note:

__builtin_types_compatible_p(unsigned char, char) is always false, and
__builtin_types_compatible_p(signed char, char) is also always false.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.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: fix some warning messages

WARN_ON() only takes a condition argument. I have changed these to
WARN() instead.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: added support for IIO_VAL_INT

Added core support for IIO_VAL_INT in write_raw_get_fmt function.

Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: resistance: add IIO_RESISTANCE channel type

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: chemical: Add IIO_CONCENTRATION channel type

There are air quality sensors that report data back in parts per million
of VOC (Volatile Organic Compounds) which are usually indexed from CO2
or another common pollutant.

This patchset adds an IIO_CONCENTRATION type that returns a percentage
of substance because no other channels types fit this use case.
Modifiers for IIO_MOD_CO2 and IIO_MOD_VOC gas types are defined.

Signed-off-by: Matt Ranostay <mranostay@gmail.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: percolate error if event fd fails

This makes the error from iio_event_getfd() percolate up
to userspace properly so we can know for sure there is no
events on this device (-ENODEV returned). Before this patch
we would bail out looking for the unsupported events on the
erroneous (negative) file descriptor.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Add function params for kernel docs

This patch adds the missing fields in kernel docs to remove
some warnings that appear when the IIO Documentation DocBook
is generated.

Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add missing modifier names to core

some are documented, others are in iio_event_monitor.c which
was recently moved from staging

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

iio: Add I/Q modifiers

I/Q modifiers can be used to denote signals which are represented by a
in-phase and a quadrature component.

The ABI documentation describes the I and Q modifiers for current and
voltage channels for now as those will be the most likely users.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
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: core: Fix double free.

When an error occurred during event registration memory was freed twice
resulting in kernel memory corruption and a crash in unrelated code.

The problem was caused by
iio_device_unregister_eventset()
iio_device_unregister_sysfs()

being called twice, once on the error path and then
again via iio_dev_release().

Fix this by making these two functions idempotent so they
may be called multiple times.

The problem was observed before applying
78b33216 iio:core: Handle error when mask type is not separate

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Cc: <Stable@vger.kernel.org>
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: core: Introduce IIO_VELOCITY and IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z

Some devices export the current speed value of the user.

One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that computes the speed of the user based on the number of steps and
stride length.

Introduce a new channel type VELOCITY and a modifier for the magniture or
norm of the velocity vector, IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z.

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

iio: core: Introduce DISTANCE channel type

Some devices export an estimation of the distance the user has covered
since the last reset.

One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that computes the distance based on the stride length and step rate.

Introduce a new channel type DISTANCE to export these values.

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

iio: core: Introduce ENERGY channel type

Human activity sensors report the energy burnt by the user.
One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that computes the number of calories based on weight and step rate.

Introduce a new channel type ENERGY to export these values.

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

iio: ensure scan index is unique at device register

Having two or more channels with the same positive scan_index field
makes no sense if the device supports buffering. Prevent this situation
by failing to register such a device.

Signed-off-by: Vlad Dogaru <vlad.dogaru@intel.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Get rid of misleading comment

This comment did not fit here. It explains why devm_kmalloc
uses dr_alloc. Generally is not needed at all.

Signed-off-by: Karol Wrona <k.wrona@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Move buffer registration to the core

Originally device and buffer registration were kept as separate operations
in IIO to allow to register two distinct sets of channels for buffered and
non-buffered operations. This has since already been further restricted and
the channel set registered for the buffer needs to be a subset of the
channel set registered for the device. Additionally the possibility to not
have a raw (or processed) attribute for a channel which was registered for
the device was added a while ago. This means it is possible to not register
any device level attributes for a channel even if it is registered for the
device. Also if a channel's scan_index is set to -1 and the channel is
registered for the buffer it is ignored.

So in summary it means it is possible to register the same channel array for
both the device and the buffer yet still end up with distinctive sets of
channels for both of them. This makes the argument for having to have to
manually register the channels for both the device and the buffer invalid.
Considering that the vast majority of all drivers want to register the same
set of channels for both the buffer and the device it makes sense to move
the buffer registration into the core to avoid some boiler-plate code in the
device driver setup path.

Signed-off-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: core: Introduce IIO_ACTIVITY channel

This channel will be used for exposing information about
activity composite sensors. Activities supported so far:
* running
* jogging
* walking
* still

THRESHOLD event is used to signal a change in the activity
state.

We associate a confidence interval for each activity expressed
as a percentage from 0 to 100.
* 0, means the sensor IS NOT reporting that activity.
* 100, means the sensor IS reporting that activity.

Users of this interface have two possible means to gather
information about the ongoing activities.

1. Event based, via event file descriptor
* sensor may report an event when ENTERING an activity or LEAVING
an activity based on a threshold value.
* drivers will wake up applications waiting data on the event fd

2. Polling, by reading the sysfs associated attribute files:
* /sys/bus/iio/devices/iio:device0/in_activity_running_input
expressed as percentage confidence value from 0 to 100.

This will offer an interface for Android significant motion
composite sensor defined here:
http://source.android.com/devices/sensors/composite_sensors.html

Activities listed above are supported by Freescale's MMA9553 sensor:
http://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: types: Added support for rotation from north usage attributes

Added the rotation from north usage attributes to the iio modifier enum and to the iio modifier names array.

Signed-off-by: Reyad Attiyat <reyad.attiyat@gmail.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add TEMP_AMBIENT and TEMP_OBJECT channel modifiers

useful for contactless temperature sensors to distinguish
between the ambient temperature and the temperature of the object

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

IIO: core: Add quaternion modifier

Added quaternion in the list of supported modifiers.

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:core: Fix bug in length of event info_mask and catch unhandled bits set in masks.

The unhandled bits case was highlighted by smatch:
CHECK drivers/iio/industrialio-core.c
drivers/iio/industrialio-core.c:719 iio_device_add_info_mask_type() error: buffer overflow 'iio_chan_info_postfix' 17 <= 31
CC [M] drivers/iio/industrialio-core.o
CHECK drivers/iio/industrialio-event.c
drivers/iio/industrialio-event.c:327 iio_device_add_event() error: buffer overflow 'iio_ev_info_text' 3 <= 3

The incorrect limit for the for_each_set_bit loop was noticed whilst fixing
this other case. Note that as we only have 3 possible entries a the moment
and the value was set to 4, the bug would not have any effect currently.
It will bite fairly soon though, so best fix it now.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>

iio: force snprintf for PAGE_SIZE bufs

This is a tiny preventative measure to make sure we can't write beyond
PAGE_SIZE on the buffers being used in sysfs for iio. There is currently
no way for this to happen, but the change makes this code more robust
for the future.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Avoid unnecessary kasprintf

name_format already contains the final name and no format characters. So the
code basically reads:

dev_attr->attr.name = kstrdup(GFP_KERNEL, name_format);
if (dev_attr->attr.name == NULL)
...
kfree(name_format);

Which means we can save one alloc and free pair per attribute name if we
directly assign name_format to dev_attr->attr.name.

The patch also renames name_format to name to denote that this is indeed the
final name and has no format characters in it.

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

iio: Don't include extended name in shared attributes

The extended name is channel specific and should not be included in shared
attributes.

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

iio get rid of unneccessary error_ret

Get rid of obsolete uses of goto error_ret and some empty lines.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add support for humidity sensors

There are already humidity sensors in the hwmon subsystem,
so we use their unit (milli percent) here as well.

Signed-off-by: Harald Geyer <harald@ccbib.org>
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: core: Add misssing braces

Silences the following checkpatch warning:
WARNING: sizeof *iio_attr should be sizeof(*iio_attr)

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: core: Use pr_err instead of printk

Use of pr_err is preferred to printk.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Factor IIO value formating into its own function

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

iio: Add a helper to free a list of IIO device attributes

We have the same code to free a IIO device attribute list in multiple place.
This patch adds a new helper function to take care of this and replaces the
custom instances with a call to the helper function. Note that we do not need to
call list_del() for each of the list items since we will never look at any of
the list items nor the list itself again.

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

iio: Wakeup poll and blocking reads when the device is unregistered

Once the device has been unregistered there won't be any new data no matter how
long a userspace application waits, so we might as well wake them up and let
them know.

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

iio: Return -ENODEV for file operations if the device has been unregistered

If the IIO device has been unregistered return -ENODEV for any further file
operations like read() and ioctl(). This avoids userspace being able to grab new
references to the device.

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

iio: Add reference counting for buffers

Since the buffer is accessed by userspace we can not just free the buffers
memory once we are done with it in kernel space. There might still be open file
descriptors and userspace still might be accessing the buffer. This patch adds
support for reference counting to the IIO buffers. When a buffer is created and
initialized its initial reference count is set to 1. Instead of freeing the
memory of the buffer the buffer's _free() function will drop that reference
again. But only after the last reference to the buffer has been dropped the
buffer the buffer's memory will be freed. The IIO device will take a reference
to its primary buffer. The patch adds a small helper function for this called
iio_device_attach_buffer() which will get a reference to the buffer and assign
the buffer to the IIO device. This function must be used instead of assigning
the buffer to the device by hand. The reference is only dropped once the IIO
device is freed and we can be sure that there are no more open file handles. A
reference to a buffer will also be taken whenever the buffer is active to avoid
the buffer being freed while data is still being send to it.

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

iio: Remove debugfs entries in iio_device_unregister()

Remove the the debugfs entries in iio_device_unregister(). Otherwise the debugfs
entries might still be accessible even though the device used in the debugfs
callback has already been freed.

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

iio: Prevent race between IIO chardev opening and IIO device free

Set the IIO device as the parent for the character device

We need to make sure that the IIO device is not freed while the character device
exists, otherwise the freeing of the IIO device might race against the file open
callback. Do this by setting the character device's parent to the IIO device,
this will cause the character device to grab a reference to the IIO device and
only release it once the character device itself has been removed.

Also move the registration of the character device before the registration of
the IIO device to avoid the (rather theoretical case) that the IIO device is
already freed again before we can add the character device and grab a reference
to the IIO device.

We also need to move the call to cdev_del() from iio_dev_release() to
iio_device_unregister() (where it should have been in the first place anyway) to
avoid a reference cycle. As iio_dev_release() is only called once all reference
are dropped, but the character device holds a reference to the IIO device.

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

iio: fix: Keep a reference to the IIO device for open file descriptors

Make sure that the IIO device is not freed while we still have file descriptors
for it.

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

iio: Stop sampling when the device is removed

Make sure to stop sampling when the device is removed, otherwise it will
continue to sample forever.

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: 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: core: Avoid double minus in sysfs output

This patch fixes the issue with double minus in output when
reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
both are negatives output string contains "--" before
digits. It is result of "-%d..." in sprintf() format.

Signed-off-by: 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: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: Add OF support

Provide bindings and parse OF data during initialization.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

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>

iio: Add pressure channel type

This patch adds support for a new IIO channel type for pressure measurements.
This can for example be used for barometric pressure sensors.

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: Accept a leading '+' sign when parsing fixed point numbers

If we encounter a leading '+' sign just skip over it.

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

iio: Reject trailing garbage when parsing fixed point numbers

When parsing a fixed point number IIO stops parsing the string once it has
reached the last requested decimal place. This means that the remainder of the
string is silently accepted regardless, of whether it is part of a valid number
or not. This patch modifies the code to scan the whole string and only accept
valid numbers. Since fract_mult is 0 after the last decimal place any digit that
may follows won't affect the result.

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

iio: Do not accept multiple '.' in fixed point numbers

Currently when parsing a fix-point number we silently skip any additional '.'
found in the string. E.g. '1.2.3.4' gets parsed as '1.234'. This patch
disallows this and returns an error if more than one '.' is encountered.

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

iio: Add a logarithmic fractional value type

For ADCs or DACs the denominator for fractional types often is a power of two.
In this case we can use a shift operation instead of the rather expensive 64 bit
division. This patch adds a new fractional type which expects the denominator to
be specified as the log2 of the actual denominator. E.g. for ADCs and DACs this
will usually be the number of significant bits.

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

iio: Introduce a new fractional value type

Currently IIO uses a decimal fixed point representations for real type numbers.
This patch introduces a new representation for rational type numbers. The number
will be expressed by specifying a numerator and denominator. For converting a
raw value to a processed value multiply it by the numerator and divide it by the
denominator.

The reasoning for introducing this new type is that for a lot of devices the
scale can be represented easily by a fractional number, but it is not possible
to represent it as fixed point number without rounding. E.g. for a simple DAC
the scale is often the reference voltage divided by the number of possible
values (Usually 2**n_bits - 1). Each driver currently implements the conversion
of this fraction to a fixed point number on its own.

Also when it comes to the in-kernel interface this allows to directly use the
fractional factors to convert a raw value to a processed value. This should on
one hand require less instructions and on the other hand increase the
precision.

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: Update email address for Jonathan Cameron.

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 channel type and modifiers for CCT and RGBC data

Add iio channel type and modifiers for Correlated Color Temperature (CCT)
and RGBC (red/green/blue/clear) data.
Add CCT and RGBC descriptions to documentation.

Changes:
Revised/condensed RGBC descriptions.

Merge and trivial fix done by Jonathan Cameron.

Signed-off-by: Jon Brenner <jbrenner@taosinc.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

IIO: Add a modifier for x^2+y^2+z^2

There will probably be a number of such modifiers eventually but
this one is used in the adis16240 accelerometer driver.

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

IIO: Add a modifier for sqrt(x^2+y^2)

There will probably be a number of such modifiers eventually but
this one is used in the adis16204 accelerometer driver.

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

iio: iio_enum_available_read: Prevent possible buffer overflow

Use scnprint instead of snprintf, because snprintf returns the number of bytes
that would have been written to the buffer if there was enough space, and as a
result writing to buf[len-1] might cause a access beyond the buffers limits.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
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 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: Fix potential use after free

There is no guarantee that the last reference to the iio device has already been
dropped when iio_device_free is called. This means that we can up calling
iio_dev_release after iio_device_free which will lead to a use after free. As
the general rule the struct containing the device should always be freed in the
release callback.

This is what this patch does, it moves freeing the iio device struct as well as
releasing the idr reference to the release callback. To ensure that the device
is not freed before calling iio_device_free the device_unregister call in
iio_device_unregister is broken apart. iio_device_unregister will now only call
device_del to remove the device from the system and iio_device_free will call
put_device to drop the reference we obtained in iio_devce_alloc.

We also have to take care that calling iio_device_free without having called
iio_device_register still works (i.e. this can happen if something failed during
device initialization). For this to work properly two minor changes were
necessary: channel_attr_list needs to be initialized in iio_device_alloc and we
have to check whether the chrdev has been registered before releasing it in
iio_device_release.

This change also brings iio_device_unregister and iio_device_free more in sync
with iio_device_register and iio_device_alloc which call device_add and
device_initialize respectively.

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: Use dev_to_iio_dev()

Replace open-coded instances of getting a iio_dev struct from a device struct
with dev_to_iio_dev().

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: introduce dB scle: IIO_VAL_INT_PLUS_MICRO_DB

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: industrialio-core: Checking NULL instead of IS_ERR for debugfs_create_dir()

If defined CONFIG_DEBUG_FS, debugfs_create_dir returns NULL on failure.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

IIO: industrialio-core: Use simple_open

Use simple_open to replace iio_debugfs_open.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-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 the core files to drivers/iio

Take the core support + the kfifo buffer implentation out of
staging. Whilst we are far from done in improving this subsystem
it is now at a stage where the userspae interfaces (provided by
the core) can be considered stable.

Drivers will follow over a longer time scale.

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