iio: event: add optional event label support

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

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

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

iio: 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>

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: fix memory leak in iio_device_register_eventset()

When iio_device_register_sysfs_group() returns failed,
iio_device_register_eventset() needs to free attrs array.

Otherwise, kmemleak would scan & report memory leak as below:

unreferenced object 0xffff88810a1cc3c0 (size 32):
comm "100-i2c-vcnl302", pid 728, jiffies 4295052307 (age 156.027s)
backtrace:
__kmalloc+0x46/0x1b0
iio_device_register_eventset at drivers/iio/industrialio-event.c:541
__iio_device_register at drivers/iio/industrialio-core.c:1959
__devm_iio_device_register at drivers/iio/industrialio-core.c:2040

Fixes: 32f171724e5c ("iio: core: rework iio device group creation")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Link: https://lore.kernel.org/r/20221115023712.3726854-1-zengheng4@huawei.com
Cc: <Stable@vger.kernel.org>
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: Add names for function definition arguments.

As reported by checkpatch.pl add missing names for function definition
arguments.

Signed-off-by: Joe Simmons-Talbott <joetalbott@gmail.com>
Link: https://lore.kernel.org/r/20220731160120.4831-1-joetalbott@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Replace strtobool() with kstrtobool()

strtobool() is deprecated and just a wrapper around kstrtobool().Replace
it with kstrtobool() so the deprecated function can be removed eventually.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220409105812.2113895-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: introduce 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/20220214073810.781016-2-cosmin.tanislav@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:event: Add timeout event info type

For adaptive threshold events, the current value is compared with a
(typically) low pass filtered version of the same signal that slowly
tracks large scale changes. However, sometimes a step change can
result in a large lag before the low pass filtered version begins
to track the signal again. Timeouts can be used to made an
instantaneous 'correction'. Documentation of this attribute
is added in a later patch.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210314181511.531414-11-jic23@kernel.org

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: 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: 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: event: NULL-ify IIO device's event_interface ref during unregister

Though we know that the iio_device_unregister_eventset() call is followed
by the free-ing of the IIO device object, we should not make this
assumption in the iio_device_unregister_eventset() function. It should
allow for the clean unregistering of the event-set, allowing a re-register
should we decide to implement this at some point later.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20200921103156.194748-2-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: event: use short-hand variable in iio_device_{un}register_eventset functions

With the recent 'iio_dev_opaque' variable name, these two functions are
looking a bit ugly.

This change uses an 'ev_int' variable for the
iio_device_{un}register_eventset functions to make the code a little easier
to read.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20200921103156.194748-1-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: move event interface on the opaque struct

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

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

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>

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

the rest of drivers/*: annotate ->poll() instances

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

iio: iio_push_event(): Don't crash if the event interface is not registered

iio_push_event() operates on a struct iio_dev. This struct can be allocated
using iio_device_alloc() which returns a valid struct iio_dev pointer. But
iio_push_event() is not safe to use on such a iio_dev until
iio_device_register() for the same device has successfully completed.

This restriction is not documented anywhere and most drivers are written
with the assumption that this restriction does not exist. The basic pattern
that is followed by all drivers looks like the following:

irqreturn_t event_callback(int irq, void *devid)
{
struct iio_dev *indio_dev = devid;
...
iio_push_event(indio_dev, ...);

return IRQ_HANDLED;
}

int driver_probe(struct device *dev)
{
struct iio_dev *indio_dev;

indio_dev = iio_device_alloc(...);

request_irq(event_irq, event_callback, ..., indio_dev);

return iio_device_register(indio_dev);
}

And while it is unlikely that the IRQ fires before iio_device_register()
completes (e.g. because the IRQ is disabled in the device) it is not
impossible and might be triggered by glitches on the signal line or
incorrect hardware configuration.

To avoid undefined behaviour in such a case extend iio_push_event() to
check if the event has been registered and discard generated events if it
has not.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
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: event: Remove negative error code from iio_event_poll

Negative return values are not supported by iio_event_poll since
its return type is unsigned int.

Fixes: f18e7a068a0a3 ("iio: Return -ENODEV for file operations if the device has been unregistered")

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

iio: event: Add missing fields in kernel docs

Fix kernel docs warnings by adding the missing fields,
each with its associated description.

Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
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: 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: Remove IIO_EV_TYPE_INSTANCE

By introducing IIO_EV_TYPE_CHANGE, IIO_EV_TYPE_INSTANCE becomes redundant.
The effect of IIO_EV_TYPE_INSTANCE can be obtained by using IIO_EV_TYPE_CHANGE
with IIO_EV_INFO_VALUE set to 1.

Remove all instances of IIO_EV_TYPE_INSTANCE and replace them with
IIO_EV_TYPE_CHANGE where needed.

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: industrialio-event: Fix typo 's/dynically/dynamically/'

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: 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_EV_DIR_NONE

For some events (e.g.: step detector) a direction does not make sense.

Add IIO_EV_DIR_NONE to be used with such events and generate sysfs event
attributes that do not contain direction.

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 : events ABI for specifying period

The iio sysfs ABI defines a way to specify period for roc and thresholds.
What: /sys/.../events/in_accel_x_thresh_rising_period
What: /sys/.../events/in_accel_x_thresh_falling_period
what: /sys/.../events/in_accel_x_roc_rising_period
What: /sys/.../events/in_accel_x_roc_falling_period

But there is no way to add period with the current event info enum.

Added IIO_EV_INFO_PERIOD and corresponding string.

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

iio:core: Handle error when mask type is not separate

When event spec is shared by multiple channels, which has definition
for mask_shared_by_type, iio_device_register_eventset fails.

For example:
static const struct iio_event_spec iio_dummy_events[] = {
{
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_RISING,
.mask_separate = BIT(IIO_EV_INFO_ENABLE),
.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE),
}, {
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_FALLING,
.mask_separate = BIT(IIO_EV_INFO_ENABLE),a
.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE),
}
};

If two channels use this event spec, this will result in error.

This change handles EBUSY error similar to iio_device_add_info_mask_type().

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Cc: Stable@vger.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:event: Fix and cleanup locking

The event code currently holds a spinlock with IRQs disabled while calling
kfifo_to_user(). kfifo_to_user() can generate a page fault though, which means
we have to be able to sleep, which is not possible if the interrupts are
disabled. The good thing is that kfifo handles concurrent read and write access
just fine as long as there is only one reader and one writer, so we do not any
locking to protect against concurrent access from the read and writer thread. It
is possible though that userspace is trying to read from the event FIFO from
multiple concurrent threads, so we need to add locking to protect against this.
This is done using a mutex. The mutex will only protect the kfifo_to_user()
call, it will not protect the waitqueue. This means that multiple threads can be
waiting for new data and once a new event is added to the FIFO all waiting
threads will be woken up. If one of those threads is unable to read any data
(because another thread already read all the data) it will go back to sleep. The
only remaining issue is that now that the clearing of the BUSY flag and the
emptying of the FIFO does no longer happen in one atomic step it is possible
that a event is added to the FIFO after it has been emptied and this sample will
be visible the next time a new event file descriptor is created. To avoid this
rather move the emptying of the FIFO from iio_event_chrdev_release to
iio_event_getfd().

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: Remove support for the legacy event config interface

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

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

iio: core: Move kernel doc to the right location

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

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

kfifo API type safety

This patch enhances the type safety for the kfifo API. It is now safe
to put const data into a non const FIFO and the API will now generate a
compiler warning when reading from the fifo where the destination
address is pointing to a const variable.

As a side effect the kfifo_put() does now expect the value of an element
instead a pointer to the element. This was suggested Russell King. It
make the handling of the kfifo_put easier since there is no need to
create a helper variable for getting the address of a pointer or to pass
integers of different sizes.

IMHO the API break is okay, since there are currently only six users of
kfifo_put().

The code is also cleaner by kicking out the "if (0)" expressions.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.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: Extend the event config interface

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

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

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

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

iio: Add 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: 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: iio_device_add_event_sysfs() bugfix

Fix mask generation for modified channels.

Signed-off-by: Lukasz Czerwinski <l.czerwinski@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: use anon_inode_getfd() with O_CLOEXEC flag

IIO uses anon_inode_get() to allocate file descriptors as part
of its ioctls. But those ioctls are lacking a flag argument
allowing userspace to choose options for the newly opened file
descriptor.

In such case it's advised to use O_CLOEXEC by default so that
userspace is allowed to choose, without race, if the file descriptor
is going to be inherited across exec().

KVM usage of anon_inode_getfd() was fixed in a previous patchset [1],
so IIO is the only subsystem using anon_inode_getfd() with a fixed set
of flags not including O_CLOEXEC.

This patch set O_CLOEXEC flag on the event file descriptor created
with anon_inode_getfd() to not leak file descriptors across exec().

Links:

- Secure File Descriptor Handling (Ulrich Drepper, 2008)
http://udrepper.livejournal.com/20407.html

- Excuse me son, but your code is leaking !!! (Dan Walsh, March 2012)
http://danwalsh.livejournal.com/53603.html

- [1] kvm: use anon_inode_getfd() with O_CLOEXEC flag
http://lkml.kernel.org/r/cover.1377372576.git.ydroneaud@opteya.com

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: events: Make iio_push_event() IRQ context save

Currently it is not save to call iio_push_event() from hard IRQ context since
the IIO event code uses spin_lock()/spin_unlock() and it is not save to mix
calls to spin_lock()/spin_unlock() from different contexts on the same lock.
E.g. if the lock is being held in iio_event_chrdev_read() and an interrupts
kicks in and the interrupt handler calls iio_push_event() we end uo with a
deadlock.

This patch updates iio_push_event() to use spin_lock_irqsave()/
spin_unlock_irqstrestore(), since it can be called from both IRQ and non-IRQ
context. All other other users of the lock, which are always run in non-IRQ
context, are updated to spin_lock_irq()/spin_unlock_irq().

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

drivers/iio/industrialio-event.c: eliminate possible double free

The function __iio_add_event_config_attrs is only called once, by the
function iio_device_register_eventset. If the call fails,
iio_device_register_eventset calls __iio_remove_event_config_attrs. There
is thus no need for __iio_add_event_config_attrs to also call
__iio_remove_event_config_attrs on failure.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@r@
identifier f,free,a;
parameter list[n] ps;
type T;
expression e;
@@

f(ps,T a,...) {
... when any
when != a = e
if(...) { ... free(a); ... return ...; }
... when any
}

@@
identifier r.f,r.free;
expression x,a;
expression list[r.n] xs;
@@

* x = f(xs,a,...);
if (...) { ... free(a); ... return ...; }
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Use strict_strtouint instead of kstrtoul

strict_strto* has been deprecated in favor of kstrto*. Use strict_strtouint
respective strict_strtoint, since that is what the functions we pass the
converted values to expect.

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

iio: Fix unitialized use of list

The dev_attr list is initialized in __iio_add_event_config_attrs which
is called only when indio_dev->channels is true. Nevertheless the list
is used unconditionally later in iio_device_register_eventset which
results in a NULL pointer exception. To fix this unconditionally
initialize the list in iio_device_register_eventset.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.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: 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>