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What: /sys/bus/iio/devices/device[n]
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Hardware chip or device accessed by on communication port.
Corresponds to a grouping of sensor channels.
What: /sys/bus/iio/devices/trigger[n]
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
An event driven driver of data capture to an in kernel buffer.
May be provided by a device driver that also has an IIO device
based on hardware generated events (e.g. data ready) or
provided by a separate driver for other hardware (e.g.
periodic timer, gpio or high resolution timer).
Contains trigger type specific elements. These do not
generalize well and hence are not documented in this file.
What: /sys/bus/iio/devices/device[n]:buffer
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Link to /sys/class/iio/device[n]/device[n]:buffer. n indicates
the device with which this buffer buffer is associated.
What: /sys/.../device[n]/name
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Description of the physical chip / device. Typically a part
number.
What: /sys/.../device[n]/sampling_frequency
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Some devices have internal clocks. This parameter sets the
resulting sampling frequency. In many devices this
parameter has an effect on input filters etc rather than
simply controlling when the input is sampled. As this
effects datardy triggers, hardware buffers and the sysfs
direct access interfaces, it may be found in any of the
relevant directories. If it effects all of the above
then it is to be found in the base device directory as here.
What: /sys/.../device[n]/sampling_frequency_available
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
When the internal sampling clock can only take a small
discrete set of values, this file lists those availale.
What: /sys/.../device[n]/in[m][_name]_raw
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Raw (unscaled no bias removal etc) voltage measurement from
channel m. name is used in special cases where this does
not correspond to externally available input (e.g. supply
voltage monitoring in which case the file is in_supply_raw).
If the device supports events on this channel then m must be
specified (even on named channels) so as to allow the source
of event codes to be identified.
What: /sys/.../device[n]/in[m][_name]_offset
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
If known for a device, offset to be added to in[m]_raw prior
to scaling by in[_name][m]_scale in order to obtain voltage in
millivolts. Not present if the offset is always 0 or unknown.
If m is not present, then voltage offset applies to all in
channels. May be writable if a variable offset is controlled
by the device. Note that this is different to calibbias which
is for devices that apply offsets to compensate for variation
between different instances of the part, typically adjusted by
using some hardware supported calibration procedure.
What: /sys/.../device[n]/in[m][_name]_offset_available
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
If a small number of discrete offset values are available, this
will be a space separated list. If these are independant (but
options the same) for individual offsets then m should not be
present.
What: /sys/.../device[n]/in[m][_name]_offset_[min|max]
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
If a more or less continuous range of voltage offsets are
supported then these specify the minimum and maximum. If shared
by all in channels then m is not present.
What: /sys/.../device[n]/in[m][_name]_calibbias
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Hardware applied calibration offset. (assumed to fix production
inaccuracies)
What /sys/.../device[n]/in[m][_name]_calibscale
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Hardware applied calibration scale factor. (assumed to fix
production inaccuracies)
What: /sys/.../device[n]/in[m][_name]_scale
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
If known for a device, scale to be applied to volt[m]_raw post
addition of in[_name][m]_offset in order to obtain the measured
voltage in millivolts. If shared across all in channels then
m is not present.
What: /sys/.../device[n]/in[m]-in[o]_raw
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Raw (unscaled) differential voltage measurement equivalent to
channel m - channel o where these channel numbers apply to the
physically equivalent inputs when non differential readings are
separately available. In differential only parts, then all that
is required is a consistent labelling.
What: /sys/.../device[n]/accel[_x|_y|_z][m]_raw
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Acceleration in direction x, y or z (may be arbitrarily assigned
but should match other such assignments on device)
channel m (not present if only one accelerometer channel at
this orientation). Has all of the equivalent parameters as per
in[m]. Units after application of scale and offset are m/s^2.
What: /sys/.../device[n]/gyro[_x|_y|_z][m]_raw
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Angular velocity about axis x, y or z (may be arbitrarily
assigned) channel m (not present if only one gyroscope at
this orientation).
Data converted by application of offset then scale to
radians per second. Has all the equivalent parameters as
per in[m].
What: /sys/.../device[n]/incli[_x|_y|_z][m]_raw
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Inclination raw reading about axis x, y or z (may be arbitarily
assigned) channel m (not present if only one inclinometer at
this orientation). Data converted by application of offset
and scale to Degrees.
What: /sys/.../device[n]/magn[_x|_y|_z][m]_raw
KernelVersion: 2.6.35
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. Has all the equivalent modifiers
as per in[m].
What: /sys/.../device[n]/device[n]:event[m]
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Configuration of which hardware generated events are passed up to
userspace. Some of these are a bit complex to generalize so this
section is a work in progress.
What: /sys/.../device[n]:event[m]/dev
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
major:minor character device numbers for the event line.
Taking accel_x0 as an example
What: /sys/.../device[n]:event[m]/accel_x0_thresh[_rising|_falling]_en
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Event generated when accel_x0 passes a threshold in the specfied
(_rising|_falling) direction. If the direction is not specified,
then either the device will report an event which ever direction
a single threshold value is called in (e.g.
accel_x0_<raw|input>_thresh_value) or
accel_x0_<raw|input>_thresh_rising_value and
accel_x0_<raw|input>_thresh_falling_value may take different
values, but the device can only enable both thresholds or
neither.
Note the driver will assume the last p events requested are
to be enabled where p is however many it supports (which may
vary depending on the exact set requested. So if you want to be
sure you have set what you think you have, check the contents of
these attributes after everything is configured. Drivers may
have to buffer any parameters so that they are consistent when
a given event type is enabled a future point (and not those for
whatever event was previously enabled).
What: /sys/.../accel_x0_<raw|input>_thresh[_rising|_falling]_value
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Specifies the value of threshold that the device is comparing
against for the events enabled by
accel_x0_<raw|input>_thresh[_rising|falling]_en.
If seperate exist for the two directions, but direction is
not specified for this attribute, then a single threshold value
applies to both directions.
The raw or input element of the name indicates whether the
value is in raw device units or in processed units (as _raw
and _input do on sysfs direct channel read attributes).
What: /sys/.../accel_x0_thresh[_rising|_falling]_meanperiod
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Period of time (in seconds) over which the raw channel value
is averaged before being compared with the threshold set in
accel_x0_thresh[_rising|_falling]_meanperiod. If direction is
not specified then this mean period applies to both directions.
What: /sys/.../accel_x0_thresh[_rising|_falling]_period
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Period of time (in seconds) for which the threshold must be
passed before an event is generated. If direction is not
specified then this period applies to both directions.
What: /sys/.../device[n]:event[m]/accel_x0_mag[_rising|_falling]_en
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Similar to accel_x0_thresh[_rising|_falling]_en, but here the
magnitude of the channel is compared to the threshold, not its
signed value.
What: /sys/.../accel_x0_<raw|input>_mag[_rising|_falling]_value
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
The value to which the magnitude of the channel is compared.
What: /sys/.../accel_x0_mag[_rising|_falling]_meanperiod
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Period of time (in seconds) over which the value of the channel
is averaged before being compared to the threshold
What: /sys/.../accel_x0_mag[_rising|_falling]_period
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Period of time (in seconds) for which the condition must be true
before an event occurs.
What: /sys/.../device[n]:event[m]/accel_x0_roc[_rising|_falling]_en
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Similar to accel_x0_thresh[_rising|_falling]_en, but here the
first differential is compared with the threshold.
What: /sys/.../accel_x0_<raw|input>_roc[_rising|_falling]_value
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
The value to which the first differential of the channel is
compared.
What: /sys/.../accel_x0_roc[_rising|_falling]_meanperiod
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Period of time (in seconds) over which the value of the channel
is averaged before being compared to the threshold
What: /sys/.../accel_x0_roc[_rising|_falling]_period
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Period of time (in seconds) for which the condition must be true
before an event occurs.
What: /sys/.../device[n]/device[n]:buffer:event/dev
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Buffer for device n event character device major:minor numbers.
What: /sys/.../device[n]/device[n]:buffer:access/dev
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Buffer for device n access character device o major:minor numbers.
What: /sys/.../device[n]:buffer/trigger
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
The name of the trigger source being used, as per string given
in /sys/class/iio/trigger[n]/name.
What: /sys/.../device[n]:buffer/length
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Number of scans contained by the buffer.
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
than implied directly by the scan_element parameters.
What: /sys/.../device[n]:buffer/enable
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Actually start the buffer capture up. Will start trigger
if first device and appropriate.
What: /sys/.../device[n]:buffer/alignment
KernelVersion: 2.6.35
Contact: linux-iio@vger.kernel.org
Description:
Minimum data alignment. Scan elements larger than this are
aligned 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/accel_x0_en
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
Scan element control for triggered data capture.
What: /sys/.../device[n]/buffer/scan_elements/accel[_x0]_type
KernelVersion: 2.6.37
Contact: linux-iio@vger.kernel.org
Description:
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
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.
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