iio: trigger: Add simple trigger_validation helper

Some triggers can only be attached to the IIO device that corresponds to
the same physical device. Implement generic helper which can be used as
a validate_trigger callback for such devices.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/51cd3e3e74a6addf8d333f4a109fb9c5a11086ee.1683541225.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Rename iio_trigger_poll_chained and add kernel-doc

Rename the function to iio_trigger_poll_nested. Add kernel-doc with
a note on the context where the function is expected to be called.

Signed-off-by: Mehdi Djait <mehdi.djait.k@gmail.com>
Link: https://lore.kernel.org/r/841b533cba28ca25a8e87280c44e45979166e8e2.1677761379.git.mehdi.djait.k@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Improve the kernel-doc of iio_trigger_poll

Move the kernel-doc of the function to industrialio-trigger.c
Add a note on the context where the function is expected to be called.

Signed-off-by: Mehdi Djait <mehdi.djait.k@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/bd84fc17e9d22eab998bf48720297f9a77689f45.1677761379.git.mehdi.djait.k@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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

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

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

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

iio: trigger: warn about non-registered iio trigger getting attempt

As a part of patch series about wrong trigger register() and get()
calls order in the some IIO drivers trigger initialization path:

https://lore.kernel.org/all/20220524181150.9240-1-ddrokosov@sberdevices.ru/

runtime WARN_ONCE() is added to alarm IIO driver authors who make such
a mistake.

When an IIO driver allocates a new IIO trigger, it should register it
before calling the get() operation. In other words, each IIO driver
must abide by IIO trigger alloc()/register()/get() calls order.

Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Link: https://lore.kernel.org/r/20220607183907.20017-1-ddrokosov@sberdevices.ru
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: trigger: Fix a scheduling whilst atomic issue seen on tsc2046

IIO triggers are software IRQ chips that split an incoming IRQ into
separate IRQs routed to all devices using the trigger.
When all consumers are done then a trigger callback reenable() is
called. There are a few circumstances under which this can happen
in atomic context.

1) A single user of the trigger that calls the iio_trigger_done()
function from interrupt context.
2) A race between disconnecting the last device from a trigger and
the trigger itself sucessfully being disabled.

To avoid a resulting scheduling whilst atomic, close this second corner
by using schedule_work() to ensure the reenable is not done in atomic
context.

Note that drivers must be careful to manage the interaction of
set_state() and reenable() callbacks to ensure appropriate reference
counting if they are relying on the same hardware controls.

Deliberately taking this the slow path rather than via a fixes tree
because the error has hard to hit and I would like it to soak for a while
before hitting a release kernel.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211017172209.112387-1-jic23@kernel.org

iio: set default trig->dev.parent

When allocated with [devm_]iio_trigger_alloc(), set trig device parent to
the device the trigger is allocated for by default.

It can always be reassigned in the probe routine.

Change iio_trigger_alloc() API to add the device pointer to be coherent
with devm_iio_trigger_alloc, using similar interface to
iio_device_alloc().

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210309193620.2176163-2-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:trigger: rename try_reenable() to reenable() plus return void

As we no longer support a try again if we cannot reenable the trigger
rename the function to reflect this. Also we don't do anything with
the value returned so stop it returning anything. For the few drivers
that didn't already print an error message in this patch, add such
a print.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Christian Oder <me@myself5.de>
Cc: Eugen Hristev <eugen.hristev@microchip.com>
Cc: Nishant Malpani <nish.malpani25@gmail.com>
Cc: Daniel Baluta <daniel.baluta@oss.nxp.com>
Link: https://lore.kernel.org/r/20200920132548.196452-3-jic23@kernel.org

iio: fix a kernel-doc markup

A function has a different name between their prototype
and its kernel-doc markup.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/46622c3bdcffb76e79719f0fe5011c2952960b32.1603469755.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: drop devm_iio_trigger_unregister() API call

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

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

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: add field identifier for @use_count kernel-doc

Kernel-doc for @use_count does not currently have a field identifier.
All the rest of the fields do. @use_count is used internally and should
not be accessed directly by the driver so it should be marked as so.

Add [INTERN] identifier to @use_count field.

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

iio: add kernel-doc for field @owner

When building kernel documentation sphinx emits the following warning

warning: No description found for parameter 'owner'

Add description for struct member 'owner'.

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

iio: drop iio_info.driver_module and iio_trigger_ops.owner.

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

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

iio: triggers: Use macros to avoid boilerplate assignment of owner.

This trig_ops.owner assignment occurs in all trigger drivers and
can be simply automated using a macro as has been done in many
other places in the kernel.

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

PATCH] iio: Fix some documentation warnings

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

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

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

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

Fix the formatting and silence the warnings.

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

iio:trigger: Add helper function to verify that a trigger belongs to the same device

Some triggers can only be attached to the IIO device that corresponds to
the same physical device. Currently each driver that requires this
implements its own trigger validation function.

Introduce a new helper function called iio_trigger_validate_own_device()
that can be used to do this check. Having a common implementation avoids
code duplication and unnecessary boiler-plate code.

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

iio: trigger: helpers to determine own trigger

This adds a helper function to the IIO trigger framework:

iio_trigger_using_own(): for an IIO device, this tells
whether the device is using itself as a trigger.
This is true if the indio device:
(A) supplies a trigger and
(B) has assigned its own buffer poll function to use this
trigger.

This helper function is good when constructing triggered,
buffered drivers that can either use its own hardware *OR*
an external trigger such as a HRTimer or even the trigger from
a totally different sensor.

Under such circumstances it is important to know for example
if the timestamp from the same trigger hardware should be used
when populating the buffer: if iio_trigger_using_own() is true,
we can use this timestamp, else we need to pick a unique
timestamp directly in the trigger handler.

For this to work of course IIO devices registering hardware
triggers must follow the convention to set the parent device
properly, as as well as setting the parent of the IIO device
itself.

When a new poll function is attached, we check if the parent
device of the IIO of the poll function is the same as the
parent device of the trigger and in that case we conclude that
the hardware is using itself as trigger.

Cc: Giuseppe Barba <giuseppe.barba@st.com>
Cc: Denis Ciocca <denis.ciocca@st.com>
Cc: Crestez Dan Leonard <leonard.crestez@intel.com>
Cc: Gregor Boirie <gregor.boirie@parrot.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:trigger: add resource managed (un)register

Add resource managed devm_iio_trigger_register() and
devm_iio_triger_unregister() to automatically clean up registered triggers
allocated by IIO drivers, thus leading to simplified IIO drivers code.

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

iio: trigger: allow immutable triggers to be assigned

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

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

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

iio: declare struct to fix warning

When compile iio related driver the following warning shown:

include/linux/iio/trigger.h:35:34: warning: 'struct iio_trigger'
declared inside parameter list
int (*set_trigger_state)(struct iio_trigger *trig, bool state);

include/linux/iio/trigger.h:38:18: warning: 'struct iio_dev'
declared inside parameter list
struct iio_dev *indio_dev);

'struct iio_dev' and 'struct iio_trigger' was used before declaration,
forward declaration for these structs to fix warning.

Signed-off-by: Pengyu Ma <pengyu.ma@windriver.com>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:trigger: modify return value for iio_trigger_get

Instead of a void function, return the trigger pointer.

Whilst not in of itself a fix, this makes the following set of
7 fixes cleaner than they would otherwise be.

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

iio: Remove timestamp argument from iio_trigger_poll() and iio_trigger_poll_chained()

argument has been ignored; adjust drivers accordingly

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

iio:trigger: Fix use_count race condition

When using more than one trigger consumer it can happen that multiple threads
perform a read-modify-update cycle on 'use_count' concurrently. This can cause
updates to be lost and use_count can get stuck at non-zero value, in which case
the IIO core assumes that at least one thread is still running and will wait for
it to finish before running any trigger handlers again. This effectively renders
the trigger disabled and a reboot is necessary before it can be used again. To
fix this make use_count an atomic variable. Also set it to the number of
consumers before starting the first consumer, otherwise it might happen that
use_count drops to 0 even though not all consumers have been run yet.

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

iio:trigger: Use dev_{set,get}_drvdata for private data management

Use dev_{set,get}_drvdata for managing private data attached to a trigger
instead of using a custom field in the iio_trigger struct.

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

iio:trigger: Introduce iio_tigger_{set,get}_drvdata

Introduce iio_tigger_{set,get}_drvdata which allows to attach driver specific
data to a trigger. The functions wrap access to the triggers private_data field
and all current users are updated to use iio_tigger_{set,get}_drvdata instead of
directly accessing the private_data field. This is the first step towards
removing the private_data field from the iio_trigger struct.

The following coccinelle script has been used to update the drivers:
<smpl>
@@
struct iio_trigger *trigger;
expression priv;
@@
-trigger->private_data = priv
+iio_trigger_set_drv_data(trigger, priv)

@@
struct iio_trigger *trigger;
@@
-trigger->private_data
+iio_trigger_get_drv_data(trigger)
</smpl>

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

iio:triggers Protect functions in triggers.h from use when not compiled

Also include a couple of forward defs of struct iio_trigger and struct
iio_trigger_ops to avoid doing this in each driver.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Denis Ciocca <denis.ciocca@st.com>

iio: whitespace cleanup and removal of semicolon after functions

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

iio: document missing elements

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

staging:iio: Streamline API function naming

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

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

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

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

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

IIO: Move core headers to include/linux/iio

Step 1 in moving the IIO core out of staging.

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