Commit 5770b8ff authored by Manuel Stahl's avatar Manuel Stahl Committed by Greg Kroah-Hartman

staging: iio partial documentation update

Signed-off-by: default avatarManuel Stahl <manuel.stahl@iis.fraunhofer.de>
Signed-off-by: default avatarJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent bf32963c
......@@ -47,10 +47,8 @@ request_update
If parameters have changed that require reinitialization or configuration of
the ring buffer this will trigger it.
get_bpd, set_bpd
Get/set the number of bytes for a given reading (single element, not sample set)
The value of bps (bytes per set) is created from a combination of this and the
enabled scan elements.
get_bytes_per_datum, set_bytes_per_datum
Get/set the number of bytes for a complete scan. (All samples + timestamp)
get_length / set_length
Get/set the number of sample sets that may be held by the buffer.
......
......@@ -158,7 +158,7 @@ Contact: linux-iio@vger.kernel.org
Description:
Magnetic field along axis x, y or z (may be arbitrarily assigned)
channel m (not present if only one magnetometer at this orientation).
Data converted by application of offset then scale to Gauss
Data converted by application of offset then scale to Gauss.
Has all the equivalent modifiers as per in[m].
What: /sys/.../device[n]/device[n]:event[m]
......@@ -212,39 +212,6 @@ Description:
The actual value of the threshold in raw device units obtained by
reverse application of scale and offfset to the acceleration in m/s^2.
What: /sys/.../device[n]/scan_elements
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Directory containing interfaces for elements that will be captured
for a single triggered sample set in the buffer.
What: /sys/.../device[n]/scan_elements/[m]_accel_x0_en
KernelVersion: 2.6.35
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.
What: /sys/.../device[n]/scan_elements/accel[_x0]_precision
KernelVersion: 2.6.35
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.
What: /sys/.../device[n]/scan_elements/accel[_x0]_shift
KernelVersion: 2.6.35
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.
What: /sys/.../device[n]/device[n]:buffer:event/dev
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
......@@ -270,8 +237,8 @@ Contact: linux-iio@vger.kernel.org
Description:
Number of scans contained by the buffer.
What: /sys/.../device[n]:buffer/bps
KernelVersion: 2.6.35
What: /sys/.../device[n]:buffer/bytes_per_datum
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Bytes per scan. Due to alignment fun, the scan may be larger
......@@ -292,3 +259,36 @@ Description:
to the nearest power of 2 times this. (may not be true in weird
hardware buffers that pack data well)
What: /sys/.../device[n]/buffer/scan_elements
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
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
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.
What: /sys/.../device[n]/buffer/scan_elements/accel[_x0]_precision
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.
What: /sys/.../device[n]/buffer/scan_elements/accel[_x0]_shift
KernelVersion: 2.6.37
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.
......@@ -7,17 +7,14 @@ Typical sysfs entries (pruned for clarity)
/sys/class/iio
device0 - iio_dev related elements
name - driver specific identifier (here lis3l02dq)
accel_x - polled (or from ring) raw readout of acceleration
accel_x_gain - hardware gain (calibration)
accel_x_offset - hardware offset (calibration)
available_sampling_frequency
accel_x_raw - polled (or from ring) raw readout of acceleration
accel_x_offset - offset to be applied to the raw reading
accel_x_scale - scale to be applied to the raw reading and offset
accel_x_calibbias - hardware offset (calibration)
accel_x_calibscale - hardware gain (calibration)
available_sampling_frequency - what options are there
sampling_frequency_available - what options are there
sampling_frequency - control of internal sampling frequency
scan_elements - controls which channels will be stored in the ring buffer
scan_en_accel_x
scan_en_accel_y
scan_en_timestamp
device - link to underlying hardware device
uevent - udev related element
......@@ -30,23 +27,28 @@ Typical sysfs entries (pruned for clarity)
dev - major:minor for the chrdev (note major allocation dynamic)
trigger - consumer attachement
current_trigger - name based association with a trigger
ring_buffer0 - ring buffer interface
bps - byptes per sample (read only), dependant on scan element selection
device0:buffer0 - ring buffer interface
bytes_per_datum - byptes per complete datum (read only),
dependant on scan element selection
length - (rw) specificy length fo software ring buffer (typically ro in hw case)
ring_enable - turn the ring on. If its the first to be enabled attached to this
trigger will also enable the trigger.
ring_access0
enable - turn the ring on. If its the first to be enabled attached to this
trigger will also enable the trigger.
device0:buffer0:access0
dev - major:minor for ring buffer access chrdev
ring_event_line0
device0:buffer0:event0
dev - major:minor for ring buffer event chrdev
scan_elements - controls which channels will be stored in the ring buffer
accel_x_en
accel_y_en
timestamp_en
trigger0 - data ready trigger elements
name - unqiue name of trigger
Udev will create the following entries under /dev by default:
ring_access0 - ring access chrdev
ring_event0 - ring event chrdev
device0:buffer0:access0 - ring access chrdev
device0:buffer0:event0 - ring event chrdev
event_line0 - general event chrdev.
For the example code we assume the following rules have been used to ensure
......
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