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trunk/drivers/staging/iio/Documentation/sysfs-class-iio
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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What: /sys/.../device[n]/in[_name][m]_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). | ||
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What: /sys/.../device[n]/in[_name][m]_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 volt[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. | ||
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What: /sys/.../device[n]/in[_name][m]_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. | ||
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What: /sys/.../device[n]/in[_name][m]_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. | ||
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What: /sys/.../device[n]/in[_name][m]_calibbias | ||
KernelVersion: 2.6.35 | ||
Contact: linux-iio@vger.kernel.org | ||
Description: | ||
Hardware applied calibration offset. (assumed to fix production | ||
inaccuracies) | ||
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What /sys/.../device[n]/in[_name][m]_calibscale | ||
KernelVersion: 2.6.35 | ||
Contact: linux-iio@vger.kernel.org | ||
Description: | ||
Hardware applied calibration scale factor. (assumed to fix production | ||
inaccuracies) | ||
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What: /sys/.../device[n]/in[_name][m]_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 volt[m]_offset in order to obtain the measured voltage | ||
in millivolts. If shared across all in channels then m is not present. | ||
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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. | ||
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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. | ||
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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]. | ||
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What: /sys/.../device[n]/mag[_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]. | ||
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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. | ||
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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. | ||
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Taking accel_x0 as an example | ||
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What: /sys/.../device[n]:event[m]/accel_x0_thresh[_high|_low]_en | ||
KernelVersion: 2.6.35 | ||
Contact: linux-iio@vger.kernel.org | ||
Description: | ||
Event generated when accel_x0 passes a threshold in correction direction | ||
(or stays beyond one). If direction isn't specified, either triggers it. | ||
Note driver will assume last p events requested are enabled where p is | ||
however many it supports. So if you want to be sure you have | ||
set what you think you have, check the contents of these. 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 | ||
alarm was previously enabled). | ||
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What: /sys/.../device[n]:event[m]/accel_x0_roc[_high|_low]_en | ||
KernelVersion: 2.6.35 | ||
Contact: linux-iio@vger.kernel.org | ||
Description: | ||
Same as above but based on the first differential of the value. | ||
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What: /sys/.../device[n]:event[m]/accel_x0[_thresh|_roc][_high|_low]_period | ||
KernelVersion: 2.6.35 | ||
Contact: linux-iio@vger.kernel.org | ||
Description: | ||
A period of time (microsecs) for which the condition must be broken | ||
before an interrupt is triggered. Applies to all alarms if type is not | ||
specified. | ||
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What: /sys/.../device[n]:event[m]/accel_x0[_thresh|_roc][_high|_low]_value | ||
KernelVersion: 2.6.35 | ||
Contact: linux-iio@vger.kernel.org | ||
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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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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. | ||
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What: /sys/.../device[n]:buffer/length | ||
KernelVersion: 2.6.35 | ||
Contact: linux-iio@vger.kernel.org | ||
Description: | ||
Number of scans contained by the buffer. | ||
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What: /sys/.../device[n]:buffer/bps | ||
KernelVersion: 2.6.35 | ||
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. | ||
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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. | ||
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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) | ||
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