iio: Fix iio_channel_has_info

Since the info_mask split, iio_channel_has_info() is not working correctly.
info_mask_separate and info_mask_shared_by_type, it is not possible to compare
them directly with the iio_chan_info_enum enum. Correct that bit using the BIT()
macro.

Cc: <stable@vger.kernel.org> # 3.10.x
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio:trigger: device_unregister->device_del to avoid double free

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: Jonathan Cameron <jic23@kernel.org>
Reported-by: Otavio Salvador <otavio@ossystems.com.br>
Tested-by: Otavio Salvador <otavio@ossystems.com.br>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
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:buffer: Simplify iio_buffer_is_active()

We can skip having to loop through all the device's buffers to see if a certain
buffer is active, if we let the buffer's list head point to itself when the
buffer is inactive.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio:kfifo_buf: Use wake_up_interruptible_poll()

Use wake_up_interruptible_poll() instead of wake_up_interruptible() to only wake
up those threads that listen for input poll notifications.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: drop info_mask from struct iio_dev

Somehow this got missed when dropping all the code that used it
prior to the split.  Remove it now, there are no users.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
iio: refactor info mask and ext_info attribute creation.

Introduce an enum to specify whether the attribute is separate or
shared.

Factor out the bitmap handling for loop into a separate function.

Tidy up error handling and add a NULL assignment to squish a false
positive warning from GCC.

Change ext_info shared type from boolean to enum and update in all
drivers.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
iio: add info_mask_[shared_by_dir/shared_by_all]

These two additional info_mask bitmaps should allow all 'standard'
numeric attributes to be handled using the read_raw and write_raw
callbacks.  Whilst this should reduce code, the more important element
is that this makes these values easily accessible to in kernel users
of IIO devices.

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

The iio_cb_access struct is never modified so we can mark it as const.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: iio_push_to_buffers(): Change type of 'data' to const void *

Change the type of the 'data' parameter for iio_push_to_buffers() from 'u8 *' to
'const void *'. Drivers typically use the correct type (e.g. __be16 *) for their
data buffer. When passing the buffer to iio_push_to_buffers() it needs to be
cast to 'u8 *' for the compiler to not complain (and also having to add __force
if we want to keep sparse happy as well). Since the buffer implementation should
not care about the data layout (except the size of one sample) using a void
pointer is the correct thing to do. Also make it const as the buffer
implementations are not supposed to modify it.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: Remove unnecessary casts for iio_push_to_buffers()

Now that iio_push_to_buffers() takes a void pointer for the data parameter we
can remove those casts to u8*.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
staging:iio: Remove unnecessary casts for iio_push_to_buffers()

Now that iio_push_to_buffers() takes a void pointer for the data parameter we
can remove those casts to u8*.

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>

Conflicts:
	drivers/iio/industrialio-event.c
iio: Minor cleanups of industrialio-buffer

adding one return value check
fix one kerneldoc

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: Fix crash when scan_bytes is computed with active_scan_mask == NULL

if device has available_scan_masks set and the buffer is enabled without
any scan_elements enabled, in a NULL pointer is dereferenced in iio_compute_scan_bytes()

[   18.993713] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   19.002593] pgd = debd4000
[   19.005432] [00000000] *pgd=9ebc0831, *pte=00000000, *ppte=00000000
[   19.012329] Internal error: Oops: 17 [#1] PREEMPT ARM
[   19.017639] Modules linked in:
[   19.020843] CPU: 0    Not tainted  (3.9.11-00036-g75c888a-dirty #207)
[   19.027587] PC is at _find_first_bit_le+0xc/0x2c
[   19.032440] LR is at iio_compute_scan_bytes+0x2c/0xf4
[   19.037719] pc : [<c021dc60>]    lr : [<c03198d0>]    psr: 200d0013
[   19.037719] sp : debd9ed0  ip : 00000000  fp : 000802bc
[   19.049713] r10: 00000000  r9 : 00000000  r8 : deb67250
[   19.055206] r7 : 00000000  r6 : 00000000  r5 : 00000000  r4 : deb67000
[   19.062011] r3 : de96ec00  r2 : 00000000  r1 : 00000004  r0 : 00000000
[   19.068847] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   19.076324] Control: 10c5387d  Table: 9ebd4019  DAC: 00000015

problem is the rollback code in iio_update_buffers(), old_mask may be NULL (e.g. on first
call)

I'm not too confident about the fix; works for me...

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: Stop sampling when the device is removed

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

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: 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: Prevent race between IIO chardev opening and IIO device free

Set the IIO device as the parent for the character device

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

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

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

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio:buffer_cb: Add missing iio_buffer_init()

Make sure to properly initialize the IIO buffer data structure.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
iio: Pass scan mask as unsigned long

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