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Subject[PATCH 10/19] staging:iio: ABI documentation (partial)
Date
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
---
drivers/staging/iio/Documentation/sysfs-class-iio | 285 +++++++++++++++++++++
1 files changed, 285 insertions(+), 0 deletions(-)
diff --git a/drivers/staging/iio/Documentation/sysfs-class-iio b/drivers/staging/iio/Documentation/sysfs-class-iio
new file mode 100644
index 0000000..7238582
--- /dev/null
+++ b/drivers/staging/iio/Documentation/sysfs-class-iio
@@ -0,0 +1,285 @@
+
+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[_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).
+
+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.
+
+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.
+
+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.
+
+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)
+
+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)
+
+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.
+
+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]/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].
+
+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[_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).
+
+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.
+
+
+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.
+
+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.
+
+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
+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/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.
+
+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)
+
--
1.6.4.4


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