linux/include
Linus Walleij 702a7b8e06 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>
2016-09-10 16:49:14 +01:00
..
acpi treewide: replace obsolete _refok by __ref 2016-08-02 17:31:41 -04:00
asm-generic locking/qrwlock: Fix write unlock bug on big endian systems 2016-08-10 14:13:27 +02:00
clocksource
crypto
drm Merge branch 'drm-next-4.8' of git://people.freedesktop.org/~agd5f/linux into drm-next 2016-08-08 16:45:33 +10:00
dt-bindings ARM: DT updates for v4.8 2016-08-01 18:37:45 -04:00
keys
kvm KVM/ARM Changes for v4.8 - Take 2 2016-08-04 13:59:56 +02:00
linux iio: trigger: helpers to determine own trigger 2016-09-10 16:49:14 +01:00
math-emu
media dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
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misc
net virtio/vhost: new features for 4.8 2016-08-06 09:20:13 -04:00
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rdma Second round of merge items for 4.8 2016-08-04 20:26:31 -04:00
rxrpc
scsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2016-08-04 20:04:37 -04:00
soc ARM: SoC driver updates for v4.8 2016-08-01 18:36:01 -04:00
sound Merge tag 'drm-for-v4.8' of git://people.freedesktop.org/~airlied/linux 2016-08-01 21:44:08 -04:00
target
trace Luiz Capitulino noticed that the tick_stop tracepoint wasn't being parsed 2016-08-09 10:34:09 -07:00
uapi powerpc fixes for 4.8 #3 2016-08-12 12:09:44 -07:00
video
xen dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
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