iio: ABI: document temperature and humidity peak/trough raw attributes

The in_temp_peak_raw attribute is already in use, but its documentation
is still missing. The in_humidityrelative_raw must be documented for a
new iio user that supports this attribute. Add temp and humidityrelative
use cases.
When at it, remove an extra blank space in the description.

For users that support minimum values, a new in_<type>_trough_raw
attribute is required. Add this attribute and document the first uses of
it for temp and humidityrelative types.

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20231211122840.9760-1-579lpy@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

doc: iio: Document intensity scale as poorly defined

Add comment about intensity scale being poorly defined and
having no proper units.

Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20231207134200.329174-1-marex@denx.de
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: imu: Add driver for BMI323 IMU

The Bosch BMI323 is a 6-axis low-power IMU that provide measurements for
acceleration, angular rate, and temperature. This sensor includes
motion-triggered interrupt features, such as a step counter, tap detection,
and activity/inactivity interrupt capabilities.

The driver supports various functionalities, including data ready, FIFO
data handling, and events such as tap detection, step counting, and
activity interrupts.

Signed-off-by: Jagath Jog J <jagathjog1996@gmail.com>
Link: https://lore.kernel.org/r/20231013034808.8948-3-jagathjog1996@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

staging: iio: resolver: ad2s1210: implement fault events

When reading the position and velocity on the AD2S1210, there is also a
3rd byte following the two data bytes that contains the fault flag bits.
This patch adds support for reading this byte and generating events when
faults occur.

The faults are mapped to various channels and event type in order to
have a unique event for each fault.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231005-ad2s1210-mainline-v4-13-ec00746840fc@baylibre.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: Add event enums for running period and count

There are devices (such as Murata IRS-D200 PIR proximity sensor) that
check the data signal with a running period. I.e. for a specified time,
they count the number of conditions that have occurred, and then signal
if that is more than a specified amount.

`IIO_EV_INFO_PERIOD` resets when the condition no longer is true and is
therefore not suitable for these devices. Add a new `iio_event_info`
`IIO_EV_INFO_RUNNING_PERIOD` that can be used as a running period. Also
add a new `IIO_EV_INFO_RUNNING_COUNT` that can be used to specify the
number of conditions that must occur during this running period.

Signed-off-by: Waqar Hameed <waqar.hameed@axis.com>
Link: https://lore.kernel.org/r/ee4a801ae9b9c4716c7bd23d8f79f232351df8bd.1689753076.git.waqar.hameed@axis.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

doc: Make sysfs-bus-iio doc more exact

A few IIC channel descriptions explained used units as:
data is in foo "that can be processed into an" [unit] value. The "can be
processed into" is quite broad statement as it does not really explain
what this processing means. This makes units pretty much useless.

After discussion with Jonathan, it seems the units for these channels
should also be well-defined as for all other channels. The processing
means the standard scale and offset application that is used throughout
the IIO. Let's make it more obvious by stating that the units are [unit]
after scale ane offset are applied.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/41eafb0caa510cddf650cf5ff940639a184f3005.1677331779.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: document "serialnumber" sysfs attribute

Add ABI documentation for the new "serialnumber" sysfs attribute. The
first user is the bno055 IIO driver.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220907132205.28021-11-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: document pitch, yaw, roll modifiers

Introduce ABI documentation for new modifiers used for reporting rotations
expressed as euler angles (i.e. yaw, pitch, roll).

It looks like we have some unit inconsistency along various IIO modifiers:
it seems that incli is in deg, angl is in radians and rot isn't documented,
but at least the adis16209 driver has rot in deg.

Here we use deg (so angl is the only one using radians).

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220907132205.28021-6-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: document linear acceleration modifiers

Introduce ABI documentation for new IIO modifiers used for reporting
"linear acceleration" measures.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220907132205.28021-3-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add new event type gesture and use direction for single and double tap

Add new event type for tap called gesture and the direction can be used
to differentiate single and double tap. This may be used by accelerometer
sensors to express single and double tap events. For directional tap,
modifiers like IIO_MOD_(X/Y/Z) can be used along with singletap and
doubletap direction.

Signed-off-by: Jagath Jog J <jagathjog1996@gmail.com>
Link: https://lore.kernel.org/r/20220831063117.4141-2-jagathjog1996@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: ABI: Fix wrong format of differential capacitance channel ABI.

in_ only occurs once in these attributes.

Fixes: 0baf29d658c7 ("staging:iio:documentation Add abi docs for capacitance adcs.")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220626122938.582107-3-jic23@kernel.org

Documentation: ABI: testing: rtq6056: Update ABI docs

Add documentation for the usage of voltage channel integration time.

Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Link: https://lore.kernel.org/r/1658242365-27797-4-git-send-email-u0084500@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ABI: stm32-timer-trigger: Fuse unusual ABI into main doc.

We can't duplicate the description of sampling_frequency. This device
has some unusual requirements which we solved by giving a
sampling_frequency of 0 special meaning. As such add a note
about this unusual usage to the main documentation.

Whilst I don't particularly like this resolution, it is the best
I could come up with given earlier discussion on this topic.

Link: https://lore.kernel.org/linux-iio/20210315101217.00002c50@Huawei.com/
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: https://lore.kernel.org/r/20220626165511.602202-4-jic23@kernel.org

iio: ABI: Add a new location label

Add "accel-camera" when an IMU is location near the camera in a swivel
sub-assembly. These IMU are used for AR applications.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Link: https://lore.kernel.org/r/20220427190804.961697-2-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation: ABI: testing: admv1014: add ABI docs

Add documentation for the use of the Digital Attenuator gain.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20220215081216.67706-3-antoniu.miclaus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ABI: add note about configuring other attributes during buffer capture

It might be impossible to configure other attributes (e.g.: events, scale,
sampling rate) if they impact the currently active buffer capture session.

On ADXL367, writing to register before 0x2E requires the device to be
placed in standby mode, otherwise the changes might be effective for
only part of a measurement.

To ensure this requirement, the configuration attributes of the IIO
device try to claim direct mode before switching to standby mode.
During a buffer capture, direct mode cannot be claimed, and the
attribute write callback returns -EBUSY.

Describe this behavior in the buffer/enable attribute description.

Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20220214073810.781016-4-cosmin.tanislav@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ABI: document mag_referenced

Some accelerometers that support activity and inactivity
events also support a referenced mode, in which the
gravitational acceleration is taken as a point of
reference before comparing the acceleration to the
specified activity and inactivity magnitude.

For example, in the case of the ADXL367, for activity
detection, the formula is:

abs(acceleration - reference) > magnitude

Add a new event type that makes this behavior clear.

Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20220214073810.781016-3-cosmin.tanislav@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: documentation: Document scd4x calibration use

Add entries from Documentation/ABI/testing/sysfs-bus-iio-scd30
to Documentation/ABI/testing/sysfs-bus-iio. The attributes of the scd4x
and scd30 are common.

Remove Documentation/ABI/testing/sysfs-bus-iio-scd30.

Signed-off-by: Roan van Dijk <roan@protonic.nl>
Link: https://lore.kernel.org/r/20211008101706.755942-5-roan@protonic.nl
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ABI: Document in_concentration_co2_scale

Document the 'in_concentration_co2_scale' standard IIO attribute.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Link: https://lore.kernel.org/r/20210920135413.140310-5-jacopo+renesas@jmondi.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Documentation: move incompatible ABI to obsolete

Commit 63cd35f34d2e ("iio: Documentation: update definitions for bufferY and scan_elements")
updated iio documentation in order to point to the newly
per-buffer API, as it is now possible to support multi buffers.

While the previous ABI will be kept forever, the best is
for applications to use the 5.11+ ABI. So, move the
legacy one ABI/obsolete.

This fixes an issue with scripts/get_abi.pl, that doesn't
accept two different Kernel version support for the same
API set.

Fixes: 63cd35f34d2e ("iio: Documentation: update definitions for bufferY and scan_elements")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/a2c802049adee6a5710a58082cfdc1132c5e4c11.1619532170.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:ABI docs: Move specific description of out_altvoltageX_frequency to main docs.

The adf4371 has channels that are very closely coupled, so additional
documentation is needed to express these constraints.
Unfortunately having the same sysfs filename in multiple documentation
does not work well when generating automated documentation.
To avoid this issue, we add a new device specific description to the
main docs and remove the one in the device specific file.

Fixes
$ scripts/get_abi.pl validate
Warning: /sys/bus/iio/devices/iio:deviceX/out_altvoltageY_frequency is defined 2 times: ./Documentation/ABI/testing/sysfs-bus-iio-frequency-adf4371:0 ./Documentation/ABI/testing/sysfs-bus-iio:599

Cc: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reported-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20210117153816.696693-8-jic23@kernel.org

iio:ABI docs: Fix issue around repeated definition of out_currentY_raw

This one is challenging as both the places this appears in specific drivers
are making 'unusual' uses of what looks like a simple output current
channel.
As a side note, this was particular bit of ABI occurs in other drivers
where the use is much more straight forward e.g. dac/ad5421

This patch attempts to make a best effort of adding it to the main docs but
retaining enough information. Both of these drivers probably need
specific documents being written to describe their unusual interfaces, but
those should be in the main documentation, not under Documentation/ABI.
That is a non trivial job so left for another time.

Fixes
$ scripts/get_abi.pl validate
Warning: /sys/bus/iio/devices/iio:deviceX/out_currentY_raw is defined 2 times: ./Documentation/ABI/testing/sysfs-bus-iio-light-lm3533-als:43 ./Documentation/ABI/testing/sysfs-bus-iio-health-afe440x:38

Reported-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20210117153816.696693-5-jic23@kernel.org

iio:ABI docs: Fix up duplicate *_calibbias_* documentation for icm42600

This device has the unusual characteristic that the calibbias values
have well defined units (more commonly they are tweaks to a DAC)
Unfortunately the previous approach of having more specific documentation
in sysfs-bus-iio-icm42600 results in warnings during the documentation
build and random ordering in the resulting documentation.

To avoid this, add a note to the main documentation on this special
characteristic for the icm42600. The _available for calibbias was
missing from the main sysfs-bus-iio docs so also add that, allowing
us to drop the icm42600 specific file.

Fixes
$ scripts/get_abi.pl validate warning:
Warning: /sys/bus/iio/devices/iio:deviceX/in_accel_x_calibbias is defined 2 times: ./Documentation/ABI/testing/sysfs-bus-iio-icm42600:0 ./Documentation/ABI/testing/sysfs-bus-iio:394
Warning: /sys/bus/iio/devices/iio:deviceX/in_accel_y_calibbias is defined 2 times: ./Documentation/ABI/testing/sysfs-bus-iio-icm42600:1 ./Documentation/ABI/testing/sysfs-bus-iio:395
Warning: /sys/bus/iio/devices/iio:deviceX/in_accel_z_calibbias is defined 2 times: ./Documentation/ABI/testing/sysfs-bus-iio-icm42600:2 ./Documentation/ABI/testing/sysfs-bus-iio:396
Warning: /sys/bus/iio/devices/iio:deviceX/in_anglvel_x_calibbias is defined 2 times: ./Documentation/ABI/testing/sysfs-bus-iio-icm42600:3 ./Documentation/ABI/testing/sysfs-bus-iio:397
Warning: /sys/bus/iio/devices/iio:deviceX/in_anglvel_y_calibbias is defined 2 times: ./Documentation/ABI/testing/sysfs-bus-iio-icm42600:4 ./Documentation/ABI/testing/sysfs-bus-iio:398
Warning: /sys/bus/iio/devices/iio:deviceX/in_anglvel_z_calibbias is defined 2 times: ./Documentation/ABI/testing/sysfs-bus-iio-icm42600:5 ./Documentation/ABI/testing/sysfs-bus-iio:399

Cc: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Reported-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20210117153816.696693-2-jic23@kernel.org

iio: ABI: sysfs-bus-iio: avoid a warning when doc is built

The description of those vars produce this warning:
Documentation/ABI/testing/sysfs-bus-iio:799: WARNING: Inline emphasis start-string without end-string.

Due to an asterisk, which is the markup for emphasis. One possible
fix would be to use ``*_timeout`` to avoid it, but looking at
the descriptions of other fields in this file, a common pattern
is to refer to "these" when talking about the API calls that
are described.

So, change the text in order to preserve the meaning while
avoiding the need of using an asterisk there.

Reported-by: Jonathan Corbet <corbet@lwn.net>
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/dbf0d94f85217f103d77dc8389c8db272f5702d2.1621944866.git.mchehab+huawei@kernel.org
[jc fixed specifiy->specify]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

iio: ABI: sysfs-bus-iio: fix a typo

Descrption -> Description

This causes some errors when parsed via scripts/get_abi.pl.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/fa90a2deebac80da42b1ad4cf570c4ace436577d.1621944866.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

iio:Documentation:ABI Add missing elements as used by the adi,ad7150

Main additions are around thresh_adaptive. This has been supported
by the core of IIO for a long time, but no driver that uses it has
previously graduated from staging, hence we are missing Docs.

Otherwise, just new entries in existing lists.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210314181511.531414-22-jic23@kernel.org

iio: Documentation: update definitions for bufferY and scan_elements

Since the new change to the IIO buffer infrastructure, the buffer/ and
scan_elements/ directories have been merged into bufferY/ to have some
attributes available per-buffer.

This change updates the ABI docs to reflect this change.

The hwfifo attributes are not updated, as for now these should be used
via the legacy buffer/ directory until they are moved into core.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210217083438.37865-2-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: documentation: Document accelerometer label use

Some 2-in-1 laptops / convertibles with 360° (yoga-style) hinges,
have 2 accelerometers, 1 in their base and 1 in their display.

In many cases the kernel can detect the location of each accelerometer
based on e.g. information from the ACPI tables.

It is important for userspace to know the location of the 2 accelerometers.
Rather then adding a new sysfs-attribute for this we can relay this
information to userspace by using standardized label strings for this.
This mirrors how this is done for proximity sensors.

This commit documents 2 new standardized label strings for this purpose:
"accel-base"
"accel-display"

Note the "base" and "display" suffixes were chosen to match the values
used for the systemd/udev hwdb.d/60-sensor.hwdb file's ACCEL_LOCATION
property.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Mark Pearson <mpearson@lenovo.com>
Cc: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210215191003.698888-2-hdegoede@redhat.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: documentation: Document proximity sensor label use

Add an entry to Documentation/ABI/testing/sysfs-bus-iio for
the new device label sysfs-attribute support.

And document the standardized labels which may be used with proximity
sensors to hint userspace about the intended use of the sensor.

Using labels to differentiate between the multiple proximity sensors
which a modern laptop/tablet may have was discussed in this thread:
https://lore.kernel.org/linux-iio/9f9b0ff6-3bf1-63c4-eb36-901cecd7c4d9@redhat.com/

As mentioned there the "proximity-wifi*" labels are already being used
in this manner on some chromebooks, see e.g.:
arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
arch/arm64/boot/dts/qcom/sc7180-trogdor-lte-sku.dtsi

And the "proximity-palmrest" and "proximity-lap" labels are intended
to be used with the lap and palmrest sensors found in recent Lenovo
ThinkPad models.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Mark Pearson <mpearson@lenovo.com>
Cc: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210215191003.698888-1-hdegoede@redhat.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Add relative hysteresis in ABI documentation

Add relative hysteresis in ABI documentation for als sensor.

Signed-off-by: Ye Xiang <xiang.ye@intel.com>
Link: https://lore.kernel.org/r/20210207070048.23935-4-xiang.ye@intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:Documentation: Add documentation for hinge sensor channels

Add channel description for hinge sensor, including channel label
attribute and raw data description.

Signed-off-by: Ye Xiang <xiang.ye@intel.com>
Link: https://lore.kernel.org/r/20201215054444.9324-4-xiang.ye@intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:Documentation: Add documentation for label channel attribute

If a label is defined 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/20200928090959.88842-2-cristian.pop@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

docs: ABI: cleanup several ABI documents

There are some ABI documents that, while they don't generate
any warnings, they have issues when parsed by get_abi.pl script
on its output result.

Address them, in order to provide a clean output.

Reviewed-by: Tom Rix <trix@redhat.com> # for fpga-manager
Reviewed-By: Kajol Jain<kjain@linux.ibm.com> # for sysfs-bus-event_source-devices-hv_gpci and sysfs-bus-event_source-devices-hv_24x7
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for IIO
Acked-by: Oded Gabbay <oded.gabbay@gmail.com> # for Habanalabs
Acked-by: Vaibhav Jain <vaibhav@linux.ibm.com> # for sysfs-bus-papr-pmem
Acked-by: Cezary Rojewski <cezary.rojewski@intel.com> # for catpt
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Ilya Dryomov <idryomov@gmail.com> # for rbd
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/5bc78e5b68ed1e9e39135173857cb2e753be868f.1604042072.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

docs: ABI: testing: make the files compatible with ReST output

Some files over there won't parse well by Sphinx.

Fix them.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for IIO
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/58cf3c2d611e0197fb215652719ebd82ca2658db.1604042072.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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>

docs: abi: iio: Use What: consistently

Change "[w|W]hat[:| ]" to What: for consistency.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Link: https://lore.kernel.org/r/20200828233156.2264689-2-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: documentation: light: Add as73211 sysfs documentation

The driver for the as73211 light sensor provides the following not yet
documented sysfs entries:
- in_intensity_(x|y|z)_raw
- in_intensity_(x|y|z)_scale
- in_intensity_sampling_frequency(_available)
- in_intensity_hardwaregain(_available)
- in_intensity_integration_time

Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation: ABI: iio: fix some spelling mistakes

This fixes some typos found while browsing the documentation.

Cc: trivial@kernel.org
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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: improve IIO_CONCENTRATION channel type description

IIO_CONCENTRATION together with INFO_RAW specifier is used for reporting
raw concentrations of pollutants. Raw value should be meaningless
before being properly scaled. Because of that description shouldn't
mention raw value unit whatsoever.

Fix this by rephrasing existing description so it follows conventions
used throughout IIO ABI docs.

Fixes: 8ff6b3bc94930 ("iio: chemical: Add IIO_CONCENTRATION channel type")
Signed-off-by: Tomasz Duszynski <tomasz.duszynski@octakon.com>
Acked-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation: ABI: document IIO thermocouple_type file

IIO core layer gained a new sysfs standard attribute "thermocouple_type".
This patch adds it to the list of documented ABI for sysfs-bus-iio

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>

Documentation: ABI: document IIO in_temp_filter_notch_center_frequency file

max31856 IIO driver introduced a new attribute
"in_temp_filter_notch_center_frequency".
This patch adds it to the list of documented ABI for sysfs-bus-iio

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: documentation: light: Add veml6030 sysfs documentation

The driver for veml6030 light sensor provides sysfs
entries like configuring cutoff for interrupt. This
commit document them.

Signed-off-by: Rishi Gupta <gupt21@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

docs: iio: add precision about sampling_frequency_available

The documentation give some exemple on what format can be expected
from sampling_frequency_available sysfs attribute

Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: counter: Add deprecation markings for IIO Counter attributes

The IIO counter subdirectory is now superceded by the Counter subsystem.
This patch adds deprecation warnings to the documentation of the
relevant IIO Counter sysfs attributes.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: Add modifiers for ethanol and H2 gases

Add ethanol and H2 gas modifiers:
* IIO_MOD_ETHANOL
* IIO_MOD_H2

Signed-off-by: Andreas Brauchli <andreas.brauchli@sensirion.com>
Acked-by: Matt Ranostay <matt.ranostay@konsulko.com>
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: fix position relative kernel version

Position relative channel type was added in 4.19 kernel version

Fixes: "3055a6cfa04ba" ("iio: Add channel for Position Relative")
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
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: 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>

staging: iio: Documentation: Add missing sysfs docs for angle channel

The iio resolver drivers in staging use angle channels. This patch
add missing documentation for this type of channel.

As was discussed in [1], radians is chosen as the unit, to match the
unit of angular velocity.

[1] https://marc.info/?l=linux-driver-devel&m=152190078308330&w=2

Signed-off-by: David Veenstra <davidjulianveenstra@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: ABI: Fix name of timestamp sysfs file

The name of the file is "current_timetamp_clock" not
"timestamp_clock".

Fixes: bc2b7dab629a ("iio:core: timestamping clock selection support")
Cc: Gregor Boirie <gregor.boirie@parrot.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: buffer: Expose data available

Add a sysfs attribute that exposes buffer data available to userspace.
This attribute can be checked at runtime to determine the overall buffer
fill level (across all allocated buffers).

Signed-off-by: Matt Fornero <matt.fornero@mathworks.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation: iio: Fix typo

Signed-off-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: dac: Add Texas Instruments 8/10/12-bit 2/4-channel DAC driver

The DACrrcS085 (rr = 08/10/12, c = 2/4) family of SPI DACs was
inherited by TI when they acquired National Semiconductor in 2011.
This driver was developed for and tested with the DAC082S085 built into
the Revolution Pi by KUNBUS, but should work with any of the other
chips as they share the same programming interface.

There is also a family of I2C DACs with just a single channel called
DACrr1C08x (rr = 08/10/12, x = 1/5). Their programming interface is
very similar and it should be possible to extend the driver for these
chips with moderate effort. Alternatively they could be integrated into
ad5446.c. (The AD5301/AD5311/AD5321 use different power-down modes but
otherwise appear to be comparable.)

Furthermore there is a family of 8-channel DACs called DACrr8S085
(rr = 08/10/12) as well as two 16-bit DACs called DAC161Sxxx
(xxx = 055/997). These are more complicated devices with support for
daisy-chaining and the ability to power down each channel separately.
They could either be handled by a separate driver or integrated into the
present driver with a larger effort.

Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation: iio: Clarify meaning of IIO_DISTANCE channel type

IIO_DISTANCE is used for two purposes: for pedometers to record the
distance covered by a walker, and to measure the distance to an object

IIO_DISTANCE is in meters while IIO_PROXIMITY is a unitless measure
indirectly proportional to distance (higher value relates to a closer
object)

Signed-off-by: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Documentation: Add missing documentation for power attribute

Commit c43a102e67db ("iio: ina2xx: add support for TI INA2xx Power Monitors")
introduced the in_powerY_raw attribute, but omitted the corresponding
documentation.

The description is correct for the INA2xx and the MAX9611 IIO drivers.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: hid-sensor-hub: Implement batch mode

HID sensor hubs using Integrated Senor Hub (ISH) has added capability to
support batch mode. This allows host processor to go to sleep for extended
duration, while the sensor hub is storing samples in its internal buffers.

'Commit f4f4673b7535 ("iio: add support for hardware fifo")' implements
feature in IIO core to implement such feature. This feature is used in
bmc150-accel-core.c to implement batch mode. This implementation allows
software device buffer watermark to be used as a hint to adjust hardware
FIFO.

But HID sensor hubs don't allow to change internal buffer size of FIFOs.
Instead an additional usage id to set "maximum report latency" is defined.
This allows host to go to sleep upto this latency period without getting
any report. Since there is no ABI to set this latency, a new attribute
"hwfifo_timeout" is added so that user mode can specify a latency.

This change checks presence of usage id to get/set maximum report latency
and if present, it will expose hwfifo_timeout.

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

iio: Generalize counting direction modes

Move counting direction documentation for 104-quad-8 to sysfs-bus-iio
to avoid duplicated for other incoming drivers

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

Documentation: iio: Fix KernelVersion in counter sysfs ABI documentation

The IIO counter driver support did not appear in the 4.9 version of the
Linux kernel. This patch fixes the KernelVersion lines of the relevant
IIO counter sysfs ABI documentation.

Fixes: 1a8f324aa1f2 ("iio: Implement counter channel type and info constants")
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Documentation: add ABI documentation for in_proximity_sampling_frequency_available

Add entry for the in_proximity_sampling_frequency_available sysfs
entry to the existing sampling_frequency_available ABI documentation.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Documentation: Add proximity unit

To follow iio guidelines Where possible we stick to the raw SI unit, so
specify meters for proximity.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

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: Documentation: fix spelling mistake: "deactived" -> "deactivated"

trivial fix to spelling mistake in iio documentation

Signed-off-by: Colin Ian King <colin.king@canonical.com>
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: 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:imu:mpu6050: enhance mounting matrix support

Add a new rotation matrix sysfs attribute compliant with IIO core
mounting matrix API.
Matrix is retrieved from "in_anglvel_mount_matrix" and
"in_accel_mount_matrix" sysfs attributes. It is declared into mpu6050 DTS
entry as a "mount-matrix" property.

Old interface is kept for backward userspace compatibility and may be
retrieved from legacy platform_data mechanism only.

Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
Acked-by: Rob Herring <robh@kernel.org>
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: ABI: Fix typo in in_proximity_raw description

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

iio:ad5064: Add support for ltc2617 and similar devices

The Linear Technology LTC2606, LTC2607, LTC2609, LTC2616, LTC2617,
LTC2619, LTC2626, LTC2627 and LTC2629 devices are very similar
to the AD5064 device.

This patch adds support for those devices.

Datasheet for LTC devices:
LTC2606, LTC2616, LTC2626: http://www.linear.com/docs/6398
LTC2607, LTC2617, LTC2627: http://www.linear.com/docs/8977
LTC2709, LTC2619, LTC2629: http://www.linear.com/docs/8477

Signed-off-by: Marc Andre <marc.andre@netline.ch>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
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>

iio: dac: mcp4725: Add basic support for MCP4726

MCP4726 is a single channel 12-bit DAC. We can support MCP4726 with
a little changes to mcp4725 driver. In power-down mode, they have
different selection of VOUT pull-down registers.

MCP4726 also has features:
- Output gain options: 1x, 2x
- Voltage reference selection: VDD, VREF (Unbuffered or Buffered)

But these are not supported in this change. (1x gain, VDD is selected)

datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22272C.pdf

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: linux-iio@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Add htu21 meas-spec driver support

Support for HTU21 temperature & humidity sensor

Signed-off-by: Ludovic Tancerel <ludovic.tancerel@maplehightech.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: resistance: Document that resistance can be output

Signed-off-by: Peter Rosin <peda@axentia.se>
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: adc: hi8435: Holt HI-8435 threshold detector

Add Holt threshold detector driver for HI-8435 chip

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

iio: Fix typos in ABI documentation

Fix typos in ABI documentation

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

iio: ABI: Clarify proximity output value

Current description for proximity measurement is ambiguous. While
the first part says that proximity is measured by observing
reflectivity, the second part incorrectly infers that reported values
should behave like a distance.

This is because of AS3935 lightning sensor which uses the proximity
API, while not being a true proximity sensor.

Note this is marked for stable as it accompanies a fix in ABI usage
to the sx9500 driver which would otherwise appear to be correct.

Fixes: 614e8842ddf ("iio: ABI: add clarification for proximity")
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Documentation: Remove bytes_per_datum attribute

Remove sysfs bytes_per_datum device attribute ABI documentation
since the attribute is not present anymore.

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

iio: ABI: Clarify proximity output value

Current description for proximity measurement is ambiguous. While
the first part says that proximity is measured by observing
reflectivity, the second part incorrectly infers that reported values
should behave like a distance.

This is because of AS3935 lightning sensor which uses the proximity
API, while not being a true proximity sensor.

Note this is marked for stable as it accompanies a fix in ABI usage
to the sx9500 driver which would otherwise appear to be correct.

Fixes: 614e8842ddf ("iio: ABI: add clarification for proximity")
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Documentation: Add additional *scale_available attributes

Added some more *scale_available attributes to the list that
are used in various drivers but were missiong from Documentation.

Signed-off-by: Adriana Reus <adriana.reus@intel.com>
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: Documentation: fix kernel version for 4.0 new ABI

Kernel version for new ABI in 4.0 has been documented
as 3.20, since the changes have been merged before the kernel
version number change.

Change kernel version from 3.20 to 4.0.

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

Documentation/ABI:iio:fix typo

Signed-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: add support for hardware fifo

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

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

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

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

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

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

iio: add watermark logic to iio read and poll

Currently the IIO buffer blocking read only wait until at least one
data element is available.
This patch makes the reader sleep until enough data is collected before
returning to userspace. This should limit the read() calls count when
trying to get data in batches.

Co-author: Yannick Bedhomme <yannick.bedhomme@mobile-devices.fr>
Signed-off-by: Josselin Costanzi <josselin.costanzi@mobile-devices.fr>
[rebased and remove buffer timeout]
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add ABI documentation for in_rot offset value

This patch adds ABI documentation entries for in_rot_offset.
At least one user for these is present that is the HID Sensors Driver.

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add ABI documentation for illuminance raw and scale values in light

This patchset adds ABI documentation for the following attributes:

in_illuminance_scale, used atleast once in al3320a staging/iio/light/
in_illuminance_calibscale, used atleast once in cm32181
in_illuminance_input, used in cm3232 at least once
in_illuminance_raw used atleast once in al3320a
in_illuminance_clear_raw and in_illuminance_ir_raw exposed by
gp2ap020a00f with modifiers IIO_MOD_LIGHT_CLEAR and
IIO_MOD_LIGHT_IR respectively.

Signed-off-by: Darshana Padmadas <darshanapadmadas@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio : Add ABI documentation for thresh falling/rising value in accel

This patch adds ABI documentation entries for
in_accel_thresh_falling_value, and in_accel_thresh_rising_value in /events.
There is at least one user for these, lis3l02dq in accel.

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add ABI documentation for proximity scan_elements

This patch adds ABI documentation entries for in_proximity_en,
in_proximity_type, and in_proximity_index in the scan_elements directory.
At least one user for these is present, the AS3935 Franklin lightning sensor.

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Reviewed-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add ABI documentation for in_magn offset value

This patch adds ABI documentation entries for in_magn_offset.
There is one user, hid-sensor-magn-3d in drivers/iio/magnetometer.

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

iio: doc: Describe scale attributes for event thresholds

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

iio: add driver for Freescale MMA9553

Add support for Freescale MMA9553L Intelligent Pedometer Platform.

The following functionalities are supported:
- step counter (counts the number of steps using a HW register)
- step detector (generates an iio event at every step the user takes)
- activity recognition (rest, walking, jogging, running)
- speed
- calories
- distance

To get accurate pedometer results, the user's height, weight and gender
need to be configured.

The specifications can be downloaded from:
http://www.freescale.com/files/sensors/doc/ref_manual/MMA955xLSWRM.pdf
http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf

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

iio: Documentation: Fix calibheight unit

Change calibheight unit from centimeters to meters
to follow iio guidelines of using SI units.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
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 CHANGE event type

A step detector will generate an interrupt each time N step are detected.
A device that has such pedometer functionality is Freescale's MMA9553L:
http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf.

Introduce IIO_EV_TYPE_CHANGE event type for events that are generated
when the channel passes a threshold on the absolute change in value.

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: ABI: add clarification for proximity

Signed-off-by: Vlad Dogaru <vlad.dogaru@intel.com>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add ABI documentation for input current readings

Add information on in_current related readings.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
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: Add ABI documentation for scaled voltage

This patch adds an entry in ABI documentation for in_voltage-voltage_scale.
It has at least one user driver, adis16220, in accel driver.

Signed-off-by: Darshana Padmadas <darshanapadmadas@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add ABI documentation for RGBC intensity hardware gain factor

This patch adds documentation for RGBC in_intensity_*_hardwaregain.
There is at least one user for these, ADJD-S311-CR999 digital color sensor
driver.

Signed-off-by: Roberta Dobrescu <roberta.dobrescu@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Add ABI documentation for offset and scaled humidity

This patch adds ABI documentation entries for in_humidityrelative_offset
and in_humidityrelative_scale, since there is at least one user for these,
Si7005 humidity and temperature sensor driver.

Signed-off-by: Roberta Dobrescu <roberta.dobrescu@gmail.com>
Reviewed-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: add ABI documentation for scaled pressure

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

iio: add documentation for current attribute

Add documentation for input current raw sysfs attribute.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Documentation: Add documentation for rotation from north sensor usage attributes

Added documentation for the sysfs attributes supported by the rotation from north
sensor.

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 ABI documentation for proximity

has been in use for a long time, but never documented
proximity is unit-less, except otherwise stated, see e.g.
the as3935 driver where it is meter

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

iio: Add ABI documentation for illuminance

has been in use for a long time, but never documented;
state that this measurement should be in lux (drivers may feel
different about this)

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

iio: Add intensity including ir and both modifiers to ABI documentation ex-post

intensity has been in use for a long time but never documented
it is beneficial to document what this is supposed to be

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

iio: Add ABI documentation for object and ambient modifiers

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

iio: Added ABI description for quaternion

Added documentation for reading quaternion components for 3D rotations.

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

iio: documentation: Add ABI documentation for *_mean_raw

Add ABI documentation for in_*_mean_raw files, which are
already supported and used in the kernel for some time.

Signed-off-by: Sebastian Reichel <sre@debian.org>
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: Add a hysteresis event info attribute

For some devices it is possible to configure a hysteresis for threshold (or
similar) events. This patch adds a new hysteresis event info type which allows
for easy creation and read/write handling of the sysfs attribute.

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

iio: Update unit of the voltage scale in the documentation

The documentation says that the result of raw * scale should be in microvolts,
but in reallity all drivers actually report the scale so that the result is in
millivolts. So update the documentation to match reallity.

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

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>

staging: iio: Documentation sysfs-bus-iio add power_mode

Add description about in_accelX_power_mode and
in_accel_power_mode_available.

Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: move ABI specification for store_eeprom; is used by ad9523, mcp4725 and ds1077 devices

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

iio: add DAC 500kohm_to_gnd to possible powerdown_modes

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

iio: ABI doc: update scan_elements sysfs paths

update ABI documentation with current paths related to scan_elements folder

Paths changed long time ago in commit: 26d25ae3f0d8ffe350aacc75b71198d6b35bd1f4

Signed-off-by: Alexandre Relange <alexandre@relange.org>
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>

iio: kernel version typo in sysfs-bus-iio

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

iio: sysfs-bus-iio typo

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

iio: nitpicking on sysfs-bus-iio

v2: address comments by Jonathan Cameron
* add more output power down modes
* spelling of etc.

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

iio: documentation: Add out_altvoltage and friends

Continuous frequency/clock generating devices, such as DDSs or PLLs
should use out_altvoltage.

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_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: Move the core abi documentation from staging

This file contains only the most generic elements. Other
class specific and device specific ABI documents will follow
over time.

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