forked from Minki/linux
staging:iio: ABI documentation (partial)
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jonathan Cameron
Greg Kroah-Hartman
parent
eaf86ff939
commit
e34d2c5fa2
285
drivers/staging/iio/Documentation/sysfs-class-iio
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285
drivers/staging/iio/Documentation/sysfs-class-iio
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What: /sys/bus/iio/devices/device[n]
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Hardware chip or device accessed by on communication port.
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Corresponds to a grouping of sensor channels.
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What: /sys/bus/iio/devices/trigger[n]
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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An event driven driver of data capture to an in kernel buffer.
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May be provided by a device driver that also has an IIO device
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based on hardware generated events (e.g. data ready) or
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provided by a separate driver for other hardware (e.g.
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periodic timer, gpio or high resolution timer).
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Contains trigger type specific elements. These do not
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generalize well and hence are not documented in this file.
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What: /sys/bus/iio/devices/device[n]:buffer
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Link to /sys/class/iio/device[n]/device[n]:buffer. n indicates the
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device with which this buffer buffer is associated.
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What: /sys/.../device[n]/name
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Description of the physical chip / device. Typically a part
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number.
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What: /sys/.../device[n]/sampling_frequency
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Some devices have internal clocks. This parameter sets the
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resulting sampling frequency. In many devices this
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parameter has an effect on input filters etc rather than
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simply controlling when the input is sampled. As this
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effects datardy triggers, hardware buffers and the sysfs
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direct access interfaces, it may be found in any of the
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relevant directories. If it effects all of the above
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then it is to be found in the base device directory as here.
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What: /sys/.../device[n]/sampling_frequency_available
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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When the internal sampling clock can only take a small
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discrete set of values, this file lists those availale.
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What: /sys/.../device[n]/in[_name][m]_raw
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Raw (unscaled no bias removal etc) voltage measurement from
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channel m. name is used in special cases where this does
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not correspond to externally available input (e.g. supply
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voltage monitoring in which case the file is in_supply_raw).
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What: /sys/.../device[n]/in[_name][m]_offset
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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If known for a device, offset to be added to in[m]_raw prior
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to scaling by volt[m]_scale in order to obtain voltage in
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millivolts. Not present if the offset is always 0 or unknown.
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If m is not present, then voltage offset applies to all in
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channels. May be writable if a variable offset is controlled
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by the device. Note that this is different to calibbias which
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is for devices that apply offsets to compensate for variation
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between different instances of the part, typically adjusted by
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using some hardware supported calibration procedure.
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What: /sys/.../device[n]/in[_name][m]_offset_available
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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If a small number of discrete offset values are available, this
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will be a space separated list. If these are independant (but
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options the same) for individual offsets then m should not be
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present.
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What: /sys/.../device[n]/in[_name][m]_offset_[min|max]
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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If a more or less continuous range of voltage offsets are supported
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then these specify the minimum and maximum. If shared by all
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in channels then m is not present.
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What: /sys/.../device[n]/in[_name][m]_calibbias
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Hardware applied calibration offset. (assumed to fix production
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inaccuracies)
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What /sys/.../device[n]/in[_name][m]_calibscale
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Hardware applied calibration scale factor. (assumed to fix production
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inaccuracies)
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What: /sys/.../device[n]/in[_name][m]_scale
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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If known for a device, scale to be applied to volt[m]_raw post
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addition of volt[m]_offset in order to obtain the measured voltage
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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
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Raw (unscaled) differential voltage measurement equivalent to
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channel m - channel o where these channel numbers apply to the physically
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equivalent inputs when non differential readings are separately available.
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In differential only parts, then all that is required is a consistent
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labelling.
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What: /sys/.../device[n]/accel[_x|_y|_z][m]_raw
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Acceleration in direction x, y or z (may be arbitrarily assigned
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but should match other such assignments on device)
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channel m (not present if only one accelerometer channel at
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this orientation). Has all of the equivalent parameters as per in[m].
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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
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Angular velocity about axis x, y or z (may be arbitrarily assigned)
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channel m (not present if only one gyroscope at this orientation).
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Data converted by application of offset then scale to
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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
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Magnetic field along axis x, y or z (may be arbitrarily assigned)
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channel m (not present if only one magnetometer at this orientation).
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Data converted by application of offset then scale to Gauss
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Has all the equivalent modifiers as per in[m].
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What: /sys/.../device[n]/device[n]:event[m]
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Configuration of which hardware generated events are passed up to
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userspace. Some of these are a bit complex to generalize so this
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section is a work in progress.
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What: /sys/.../device[n]:event[m]/dev
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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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
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Event generated when accel_x0 passes a threshold in correction direction
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(or stays beyond one). If direction isn't specified, either triggers it.
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Note driver will assume last p events requested are enabled where p is
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however many it supports. So if you want to be sure you have
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set what you think you have, check the contents of these. Drivers
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may have to buffer any parameters so that they are consistent when a
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given event type is enabled a future point (and not those for whatever
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alarm was previously enabled).
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What: /sys/.../device[n]:event[m]/accel_x0_roc[_high|_low]_en
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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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
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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A period of time (microsecs) for which the condition must be broken
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before an interrupt is triggered. Applies to all alarms if type is not
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specified.
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What: /sys/.../device[n]:event[m]/accel_x0[_thresh|_roc][_high|_low]_value
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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The actual value of the threshold in raw device units obtained by
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reverse application of scale and offfset to the acceleration in m/s^2.
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What: /sys/.../device[n]/scan_elements
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Directory containing interfaces for elements that will be captured
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for a single triggered sample set in the buffer.
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What: /sys/.../device[n]/scan_elements/[m]_accel_x0_en
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Scan element control for triggered data capture. m implies the
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ordering within the buffer. Next the type is specified with
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modifier and channel number as per the sysfs single channel
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access above.
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What: /sys/.../device[n]/scan_elements/accel[_x0]_precision
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Scan element precision within the buffer. Note that the
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data alignment must restrictions must be read from within
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buffer to work out full data alignment for data read
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via buffer_access chrdev. _x0 dropped if shared across all
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acceleration channels.
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What: /sys/.../device[n]/scan_elements/accel[_x0]_shift
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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A bit shift (to right) that must be applied prior to
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extracting the bits specified by accel[_x0]_precision.
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What: /sys/.../device[n]/device[n]:buffer:event/dev
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Buffer for device n event character device major:minor numbers.
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What: /sys/.../device[n]/device[n]:buffer:access/dev
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Buffer for device n access character device o major:minor numbers.
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What: /sys/.../device[n]:buffer/trigger
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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The name of the trigger source being used, as per string given
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in /sys/class/iio/trigger[n]/name.
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What: /sys/.../device[n]:buffer/length
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Number of scans contained by the buffer.
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What: /sys/.../device[n]:buffer/bps
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Bytes per scan. Due to alignment fun, the scan may be larger
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than implied directly by the scan_element parameters.
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What: /sys/.../device[n]:buffer/enable
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Actually start the buffer capture up. Will start trigger
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if first device and appropriate.
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What: /sys/.../device[n]:buffer/alignment
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KernelVersion: 2.6.35
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Contact: linux-iio@vger.kernel.org
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Description:
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Minimum data alignment. Scan elements larger than this are aligned
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to the nearest power of 2 times this. (may not be true in weird
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hardware buffers that pack data well)
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