In case oldtrig == trig == NULL (which happens when we set none
trigger, when there is already none set) there is a NULL pointer
dereference during iio_trigger_put(trig). Below is kernel output when
this occurs:

[   26.741790] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   26.750179] pgd = cacc0000
[   26.752936] [00000000] *pgd=8adc6835, *pte=00000000, *ppte=00000000
[   26.759531] Internal error: Oops: 17 [#1] SMP ARM
[   26.764261] Modules linked in: usb_f_ncm u_ether usb_f_acm u_serial usb_f_fs libcomposite configfs evbug
[   26.773844] CPU: 0 PID: 152 Comm: synchro Not tainted 4.12.0-rc1 #2
[   26.780128] Hardware name: Freescale i.MX6 Ultralite (Device Tree)
[   26.786329] task: cb1de200 task.stack: cac92000
[   26.790892] PC is at iio_trigger_write_current+0x188/0x1f4
[   26.796403] LR is at lock_release+0xf8/0x20c
[   26.800696] pc : [<c0736f34>]    lr : [<c016efb0>]    psr: 600d0013
[   26.800696] sp : cac93e30  ip : cac93db0  fp : cac93e5c
[   26.812193] r10: c0e64fe8  r9 : 00000000  r8 : 00000001
[   26.817436] r7 : cb190810  r6 : 00000010  r5 : 00000001  r4 : 00000000
[   26.823982] r3 : 00000000  r2 : 00000000  r1 : cb1de200  r0 : 00000000
[   26.830528] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[   26.837683] Control: 10c5387d  Table: 8acc006a  DAC: 00000051
[   26.843448] Process synchro (pid: 152, stack limit = 0xcac92210)
[   26.849475] Stack: (0xcac93e30 to 0xcac94000)
[   26.853857] 3e20:                                     00000001 c0736dac c054033c cae6b680
[   26.862060] 3e40: cae6b680 00000000 00000001 cb3f8610 cac93e74 cac93e60 c054035c c0736db8
[   26.870264] 3e60: 00000001 c054033c cac93e94 cac93e78 c029bf34 c0540348 00000000 00000000
[   26.878469] 3e80: cb3f8600 cae6b680 cac93ed4 cac93e98 c029b320 c029bef0 00000000 00000000
[   26.886672] 3ea0: 00000000 cac93f78 cb2d41fc caed3280 c029b214 cac93f78 00000001 000e20f8
[   26.894874] 3ec0: 00000001 00000000 cac93f44 cac93ed8 c0221dcc c029b220 c0e1ca39 cb2d41fc
[   26.903079] 3ee0: cac93f04 cac93ef0 c0183ef0 c0183ab0 cb2d41fc 00000000 cac93f44 cac93f08
[   26.911282] 3f00: c0225eec c0183ebc 00000001 00000000 c0223728 00000000 c0245454 00000001
[   26.919485] 3f20: 00000001 caed3280 000e20f8 cac93f78 000e20f8 00000001 cac93f74 cac93f48
[   26.927690] 3f40: c0223680 c0221da4 c0246520 c0245460 caed3283 caed3280 00000000 00000000
[   26.935893] 3f60: 000e20f8 00000001 cac93fa4 cac93f78 c0224520 c02235e4 00000000 00000000
[   26.944096] 3f80: 00000001 000e20f8 00000001 00000004 c0107f84 cac92000 00000000 cac93fa8
[   26.952299] 3fa0: c0107de0 c02244e8 00000001 000e20f8 0000000e 000e20f8 00000001 fbad2484
[   26.960502] 3fc0: 00000001 000e20f8 00000001 00000004 beb6b698 00064260 0006421c beb6b4b4
[   26.968705] 3fe0: 00000000 beb6b450 b6f219a0 b6e2f268 800d0010 0000000e cac93ff4 cac93ffc
[   26.976896] Backtrace:
[   26.979388] [<c0736dac>] (iio_trigger_write_current) from [<c054035c>] (dev_attr_store+0x20/0x2c)
[   26.988289]  r10:cb3f8610 r9:00000001 r8:00000000 r7:cae6b680 r6:cae6b680 r5:c054033c
[   26.996138]  r4:c0736dac r3:00000001
[   26.999747] [<c054033c>] (dev_attr_store) from [<c029bf34>] (sysfs_kf_write+0x50/0x54)
[   27.007686]  r5:c054033c r4:00000001
[   27.011290] [<c029bee4>] (sysfs_kf_write) from [<c029b320>] (kernfs_fop_write+0x10c/0x224)
[   27.019579]  r7:cae6b680 r6:cb3f8600 r5:00000000 r4:00000000
[   27.025271] [<c029b214>] (kernfs_fop_write) from [<c0221dcc>] (__vfs_write+0x34/0x120)
[   27.033214]  r10:00000000 r9:00000001 r8:000e20f8 r7:00000001 r6:cac93f78 r5:c029b214
[   27.041059]  r4:caed3280
[   27.043622] [<c0221d98>] (__vfs_write) from [<c0223680>] (vfs_write+0xa8/0x170)
[   27.050959]  r9:00000001 r8:000e20f8 r7:cac93f78 r6:000e20f8 r5:caed3280 r4:00000001
[   27.058731] [<c02235d8>] (vfs_write) from [<c0224520>] (SyS_write+0x44/0x98)
[   27.065806]  r9:00000001 r8:000e20f8 r7:00000000 r6:00000000 r5:caed3280 r4:caed3283
[   27.073582] [<c02244dc>] (SyS_write) from [<c0107de0>] (ret_fast_syscall+0x0/0x1c)
[   27.081179]  r9:cac92000 r8:c0107f84 r7:00000004 r6:00000001 r5:000e20f8 r4:00000001
[   27.088947] Code: 1a000009 e1a04009 e3a06010 e1a05008 (e5943000)
[   27.095244] ---[ end trace 06d1dab86d6e6bab ]---

To fix that problem call iio_trigger_put(trig) only when trig is not
NULL.

Fixes: d5d24bcc ("iio: trigger: close race condition in acquiring trigger reference")
Signed-off-by: NMarcin Niestroj <m.niestroj@grinn-global.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

1) Reverse the test for kmalloc() failure so we can pull everything
   back one tab.
2) Use gotos for unwinding.
3) Some of the extra line breaks for the 80 character limit are no
   longer needed so we can remove them.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Declare device_type structure as const as it is only stored in the
type field of a device structure. This field is of type const, so add
const to declaration of device_type structure.

File size before:
   text	   data	    bss	    dec	    hex	filename
   5389	    208	     48	   5645	   160d	iio/industrialio-trigger.o

File size after:
   text	   data	    bss	    dec	    hex	filename
   5453	    176	     48	   5677	   162d	iio/industrialio-trigger.o
Signed-off-by: NBhumika Goyal <bhumirks@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

In iio_trigger_write_current() we find the trigger we want while
holding mutex on the list of triggers, but we don't actually do a
get on it while holding mutex.  We wait until further validations
are completed and we're sure it's the one we want.  Race condition
is that it could be freed by the time we do the get.

Solution is to grab the trigger (iio_trigger_get) as soon as we
find it while holding mutex on the list of triggers.  If later
we decide it's not the right one, put it back. (iio_trigger_put).
Signed-off-by: NAlison Schofield <amsfield22@gmail.com>
Suggested-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

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

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: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

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

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

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: NGregor Boirie <gregor.boirie@parrot.com>
Acked-by: NSanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

The trigger name is documented as unique but drivers are currently
allowed to register triggers with duplicate names. This should be
considered a bug since it makes the 'current_trigger' interface
unusable.
Signed-off-by: NCrestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

When attaching a pollfunc iio_trigger_attach_poll_func will allocate a
virtual irq and call the driver's set_trigger_state function. Fix error
handling to undo previous steps if any fails.

In particular this fixes handling errors from a driver's
set_trigger_state function. When using triggered buffers a failure to
enable the trigger used to make the buffer unusable.
Signed-off-by: NCrestez Dan Leonard <leonard.crestez@intel.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

This structure has not been optional for a long time (if ever) but the
code implies that it is.  As we then use it later in a fashion that would
crash if it was in fact NULL, it's inconsistent so fix it up by removing
unnecessary checks.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Support triggered events.

This is useful for chips that don't have their own interrupt sources.
It allows to use generic/standalone iio triggers for those drivers.
Signed-off-by: NVladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Fix kernel docs warnings by adding the missing description
for each of the existing function parameters.
Signed-off-by: NCristina Opriceana <cristina.opriceana@gmail.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

argument has been ignored; adjust drivers accordingly
Signed-off-by: NPeter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Get rid of obsolete uses of goto error_ret and some empty lines.
Signed-off-by: NHartmut Knaack <knaack.h@gmx.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Use new ATTRIBUTE_GROUPS macro to declare attribute groups.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

same check is performed a new lines above
Signed-off-by: NPeter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

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

Documentation related to function should be placed above
its implementation. Move it accordingly.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Add a resource managed devm_iio_trigger_alloc()/devm_iio_triger_free()
to automatically clean up triggers allocated by IIO drivers, thus
leading to simplified IIO drivers code.
Signed-off-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: NKyunmin Park <kyungmin.park@samsung.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

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

iio_trigger unregistration and freeing has been separated in this
code for some time, but it looks like the calls to the device
handling were not appropriately updated.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Reported-by: NOtavio Salvador <otavio@ossystems.com.br>
Tested-by: NOtavio Salvador <otavio@ossystems.com.br>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>

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

The name sysfs attribute is the same for all triggers, so there is no need to
register them dynamically at runtime. Create a attribute group for it and set it
up for the bus attribute group. This also avoids a possible race condition
where the uevent for the device is sent before the name sysfs attribute has been
added.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

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

Use to_iio_trigger(dev) instead of dev_get_drvdata(dev). Both will return the
trigger which belongs to the device, but the the first on is a bit more
lightweight.

Since this is the last location where we used dev_get_drvdata() for retrieving
the trigger there is no need anymore to assign the the trigger to the devices
drvdata, so we can remove that as well.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace open-coded instances of getting a iio_dev struct from a device struct
with dev_to_iio_dev().
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NLars-Peter Clausen <lars@metafoo.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

Step 1 in moving the IIO core out of staging.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The below patch fixes some typos in various parts of the kernel, as well as fixes some comments.
Please let me know if I missed anything, and I will try to get it changed and resent.
Signed-off-by: NJustin P. Mattock <justinmattock@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Both of these are decidedly silly bugs show up whilst testing
completely different code paths.
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Postenable and predisable are called via buffer->ops so  don't
need to check if buffer exists.

The return value of iio_device_register_trigger_consumer is
always zero and it isn't checked anyway so get rid of it.
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We had a random missmatch of these two.  Lets pick the most common
and get rid of the other.  This patch covers the core.  Others
will clean up the drivers.
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

also, IIO_RING_HARDWARE_BUFFER -> IIO_BUFFER_HARDWARE

These aren't always rings so the naming should not imply that.
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Not always a ring so naming is missleading.
Also, kfifo_buf is probably first buffer to take out of staging and it
definitely isn't a ring.
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This set also includes quite a number of bug fixes of particularly
remove functions.

Necessary due to issue pointed out in Bart Van Assche's patch:
docs/driver-model: Document device.groups

V2: Rebase due to patch reordering.
V3: Pull various error fixes and cleanups out into their own patches.
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Acked-by: NMichael Hennerich <Michael.Hennerich@analog.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

All iio dependent modules statically depend on industrialio
so these aren't needed. Not sure why they originally existed,
but they aren't now.
Signed-off-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>