staging: iio: sysfs abi documentation. Add _type and _index attrs

Also remove no unused precision attr.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jonathan Cameron 2010-09-21 14:41:08 +01:00 committed by Greg Kroah-Hartman
parent 3215e31cc3
commit 10ba8ea9bd
1 changed files with 28 additions and 12 deletions

View File

@ -266,24 +266,41 @@ Description:
Directory containing interfaces for elements that will be captured
for a single triggered sample set in the buffer.
What: /sys/.../device[n]/buffer/scan_elements/[m]_accel_x0_en
What: /sys/.../device[n]/buffer/scan_elements/accel_x0_en
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Scan element control for triggered data capture. m implies the
ordering within the buffer. Next the type is specified with
modifier and channel number as per the sysfs single channel
access above.
Scan element control for triggered data capture.
What: /sys/.../device[n]/buffer/scan_elements/accel[_x0]_precision
What: /sys/.../device[n]/buffer/scan_elements/accel[_x0]_type
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Scan element precision within the buffer. Note that the
data alignment must restrictions must be read from within
buffer to work out full data alignment for data read
via buffer_access chrdev. _x0 dropped if shared across all
acceleration channels.
Description of the scan element data storage within the buffer
and hence the form in which it is read from userspace.
Form is [s|u]bits/storagebits. s or u specifies if signed
(2's complement) or unsigned. bits is the number of bits of
data and storagebits is the space (after padding) that it
occupies in the buffer. Note that some devices will have
additional information in the unused bits so to get a clean
value, the bits value must be used to mask the buffer output
value appropriately. The storagebits value also specifies the
data alignment. So s48/64 will be a signed 48 bit integer
stored in a 64 bit location aligned to a a64 bit boundary.
For other storage combinations this attribute will be extended
appropriately.
What: /sys/.../device[n]/buffer/scan_elements/accel[_x0]_index
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
A single positive integer specifying the position of this
scan element in the buffer. Note these are not dependant on
what is enabled and may not be contiguous. Thus for userspace
to establish the full layout these must be used in conjunction
with all _en attributes to establish which channels are present,
and the relevant _type attributes to establish the data storage
format.
What: /sys/.../device[n]/buffer/scan_elements/accel[_x0]_shift
KernelVersion: 2.6.37
@ -291,4 +308,3 @@ Contact: linux-iio@vger.kernel.org
Description:
A bit shift (to right) that must be applied prior to
extracting the bits specified by accel[_x0]_precision.