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@@ -1,62 +1,12 @@
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Userspace access to IIO
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-Example, ST Microelectronics LIS3L02DQ accelerometer.
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-
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-Typical sysfs entries (pruned for clarity)
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-
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-/sys/class/iio
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- device0 - iio_dev related elements
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- name - driver specific identifier (here lis3l02dq)
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- accel_x_raw - polled (or from ring) raw readout of acceleration
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- accel_x_offset - offset to be applied to the raw reading
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- accel_x_scale - scale to be applied to the raw reading and offset
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- accel_x_calibbias - hardware offset (calibration)
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- accel_x_calibscale - hardware gain (calibration)
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-
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- sampling_frequency_available - what options are there
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- sampling_frequency - control of internal sampling frequency
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- device - link to underlying hardware device
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- uevent - udev related element
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-
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- thresh - unified threshold used for detection on all axis
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- event_line0_sources - which events are enabled
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- accel_x_high - enable x axis high threshold event
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- accel_x_low - enable x axis low threshold event
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-
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- event_line0 - event interface
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- dev - major:minor for the chrdev (note major allocation dynamic)
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- trigger - consumer attachement
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- current_trigger - name based association with a trigger
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- device0:buffer0 - ring buffer interface
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- bytes_per_datum - byptes per complete datum (read only),
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- dependant on scan element selection
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- length - (rw) specificy length fo software ring buffer (typically ro in hw case)
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- enable - turn the ring on. If its the first to be enabled attached to this
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- trigger will also enable the trigger.
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- device0:buffer0:access0
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- dev - major:minor for ring buffer access chrdev
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- device0:buffer0:event0
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- dev - major:minor for ring buffer event chrdev
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- scan_elements - controls which channels will be stored in the ring buffer
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- accel_x_en
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- accel_y_en
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- timestamp_en
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-
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- trigger0 - data ready trigger elements
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- name - unqiue name of trigger
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+The sysfs attributes are documented in sysfs-bus-iio.
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Udev will create the following entries under /dev by default:
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device0:buffer0:access0 - ring access chrdev
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device0:buffer0:event0 - ring event chrdev
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-event_line0 - general event chrdev.
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-
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-For the example code we assume the following rules have been used to ensure
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-unique and consistent naming of these for the lis3l02dq in question:
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-
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-KERNEL="ring_event_line*", ID="spi1.0", DRIVER="lis3l02dq", NAME="iio/lis3l02dq_ring_event"
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-KERNEL="event_line*", ID="spi1.0", DRIVER="lis3l02dq", NAME="iio/lis3l02dq_event"
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-KERNEL="ring_access*", ID="spi1.0", DRIVER="lis3l02dq", NAME="iio/lis3l02dq_ring_access"
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+device0:event0 - general event chrdev.
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The files, lis3l02dqbuffersimple.c and iio_utils.h in this directory provide an example
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of how to use the ring buffer and event interfaces.
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