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>
1. make messages grepable (in one line)
2. include returned errno in them
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Route all buffer writes through the demux.
Addition or removal of a buffer results in tear down and
setup of all the buffers for a given device.
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Tested-by: srinivas pandruvada <srinivas.pandruvada@intel.com>
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>
Drop timestamp parameter from buffer store_to callback and subsequently from
iio_push_to_buffer. The timestamp parameter is unused and it seems likely that
it will stay unused in the future, so it should be safe to remove it.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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Merge tag 'togreg-3.6a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next
IIO: One new driver and a couple of nice cleanups.
Add a helper function for validating a scan mask for devices where exactly one
channel must be selected during sampling. This is a common case among devices
which have scan mask restrictions so it makes sense to provide this function in
the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This is useful for cases where the number of valid scan masks grows
exponentially, but it is rather easy to check whether a mask is valid or not
programmatically.
An example of such a case is a device with multiple ADCs where each ADC has a
upstream MUX, which allows to select from a number of physical channels.
+-------+ +-------+
| | | | --- Channel 1
| ADC 1 |---| MUX 1 | --- ...
| | | | --- Channel M
+-------+ +-------+
. . .
. . .
. . .
+-------+ +-------+
| | | | --- Channel M * N + 1
| ADC N |---| MUX N | --- ...
| | | | --- Channel M * N + M
+-------+ +-------+
The number of necessary scan masks for this case is (M+1)**N - 1, on the other
hand it is easy to check whether subsets for each ADC of the scanmask have only
one bit set.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
The channel set assigned to the iio device is not necessarily the same has the
channel set passed to iio_buffer_register. So to avoid possible complications
always work with the channel set pass to iio_buffer_register and ignore the
channel set assigned to the iio device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
It is not always the case that all channels can be used in buffered mode. This
patch allows channels, which can not be used in buffered mode, to set their scan
index to a negative number, which will cause iio_buffer_register to ignore the
channel.
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_scan_mask_match() returns NULL if the passed in scan mask is empty. This
will happen if no channel has been selected and buffer is enabled.
iio_sw_buffer_preenable() will assign NULL to indio_dev->active_scan_mask in
this case. As a result iio_update_demux() will cause a NULL pointer deref,
because it expects active_scan_mask to be non-NULL.
Since it does not make much sense to start data capture if there is no data to
capture this patch updates the code to fail gracefully in iio_scan_mask_match()
instead of crashing the kernel.
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>
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>
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>
Peter Meerwald
Michał Mirosław
Jonathan Cameron
Lars-Peter Clausen
Greg Kroah-Hartman