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software:linux:docs:iio:iio [28 Feb 2011 13:39] Michael Hennerich created |
software:linux:docs:iio:iio [05 Jun 2020 17:03] (current) Iulia Moldovan [IIO Overview] Grammar changes |
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| ===== IIO Overview ===== | ===== IIO Overview ===== | ||
| - | * The Industrial I/O subsystem is intended to provide support for devices that in some sense are analog to digital convertors (ADCs). | + | * The Industrial I/O subsystem is intended to provide support for devices that in some sense are analog to digital or digital to analog converters (ADCs, DACs). |
| * Devices that fall into this category are: | * Devices that fall into this category are: | ||
| * ADCs | * ADCs | ||
| Line 11: | Line 11: | ||
| * IMUs | * IMUs | ||
| * Capacitance to Digital Converters (CDCs) | * Capacitance to Digital Converters (CDCs) | ||
| - | * Pressure, Temperature and Light Sensors | + | * Pressure Sensors |
| + | * Color, Light and Proximity Sensors | ||
| + | * Temperature Sensors | ||
| + | * Magnetometers | ||
| + | * DACs | ||
| + | * DDS (Direct Digital Synthesis) | ||
| + | * PLLs (Phase Locked Loops) | ||
| + | * Variable/Programmable Gain Amplifiers (VGA, PGA) | ||
| * The overall aim is to fill the gap between the somewhat similar hwmon and input subsystems. | * The overall aim is to fill the gap between the somewhat similar hwmon and input subsystems. | ||
| * Hwmon is very much directed at low sample rate sensors used in applications such as fan speed control and temperature measurement. | * Hwmon is very much directed at low sample rate sensors used in applications such as fan speed control and temperature measurement. | ||
| - | * Input is, as it's name suggests focused on human interaction input devices.: | + | * The input is (as its name suggests) focused on human interaction input devices: |
| * Keyboard | * Keyboard | ||
| * Mouse | * Mouse | ||
| Line 21: | Line 28: | ||
| * Joystick | * Joystick | ||
| - | * In some cases there is considerable overlap between these and IIO. | + | * In some cases, there is considerable overlap between these and IIO. |
| * A typical device falling into the IIO category would be connected via SPI or I2C. | * A typical device falling into the IIO category would be connected via SPI or I2C. | ||
| - | * However typical DMA operated devices such as ones connected to a high speed synchronous serial (McBSP, SPORT) or high speed synchronous parallel (EPI, PPI) peripherals are also subject to this subsystem. | + | * However typical DMA operated devices such as ones connected to a high speed synchronous serial (McBSP, SPORT) or high speed synchronous parallel (EPI, PPI) or FPGA peripherals are also subject to this subsystem. |
| * Since latter ones unlike SPI or I2C are not generally abstracted by Linux bus drivers they are subject to processor platform dependent implementations. | * Since latter ones unlike SPI or I2C are not generally abstracted by Linux bus drivers they are subject to processor platform dependent implementations. | ||
| ===== IIO Subsystem Overview ===== | ===== IIO Subsystem Overview ===== | ||
| + | |||
| + | {{:software:linux:docs:iio:iio_block_view.png?600}} | ||
| ==== Functionality of IIO ==== | ==== Functionality of IIO ==== | ||
| * Basic device registration and handling | * Basic device registration and handling | ||
| - | * This is very simple polled access to device channels via sysfs. | + | * Polled access to device channels via sysfs. |
| * Event chrdevs | * Event chrdevs | ||
| * These are similar to input in that they provide a route to user space for hardware triggered events. Such events include threshold detectors, free-fall detectors and more complex action detection. The events themselves are currently very simple with merely an event code and a timestamp. Any data associated with the event must be accessed via polling. | * These are similar to input in that they provide a route to user space for hardware triggered events. Such events include threshold detectors, free-fall detectors and more complex action detection. The events themselves are currently very simple with merely an event code and a timestamp. Any data associated with the event must be accessed via polling. | ||
| - | <note> | + | <WRAP round help> |
| A given device may have one or more event channel. These events are turned on or off (if possible) via sysfs interfaces. | A given device may have one or more event channel. These events are turned on or off (if possible) via sysfs interfaces. | ||
| - | </note> | + | </WRAP> |
| * Hardware ring buffer support | * Hardware ring buffer support | ||
| Line 43: | Line 52: | ||
| * These greatly reduce the load on the host CPU by buffering relatively large numbers of data samples based on an internal sampling clock. | * These greatly reduce the load on the host CPU by buffering relatively large numbers of data samples based on an internal sampling clock. | ||
| * Each ring buffer typically has an event chrdev (similar to the more general ones above) to pass on events such as buffer 50% full and an access chrdev via which the raw data it self may be read back. | * Each ring buffer typically has an event chrdev (similar to the more general ones above) to pass on events such as buffer 50% full and an access chrdev via which the raw data it self may be read back. | ||
| - | * Trigger and software ring buffer support | + | * Trigger and software ring buffer (kfifo) support |
| ==== Trigger and software ring buffer support ==== | ==== Trigger and software ring buffer support ==== | ||
| Line 57: | Line 66: | ||
| * Triggers can be completely unrelated to the sensor itself | * Triggers can be completely unrelated to the sensor itself | ||
| + | === Standalone trigger drivers === | ||
| - | ==== IIO Ring Buffer ==== | + | {{page>software:linux:docs:iio:iio_snippets#Standalone trigger drivers&noheader&firstseconly&noeditbtn}} |
| + | |||
| + | ==== Industrial I/O Subsystem In-Kernel Interfaces ==== | ||
| + | |||
| + | The IIO subsystem can act as a layer under other elements of the kernel | ||
| + | providing a means of obtaining ADC type readings or of driving DAC type | ||
| + | signals. The functionality supported will grow as use cases arise. | ||
| + | ==== IIO Ring Buffer / kfifo ==== | ||
| {{:software:linux:docs:ringbuffer.png}} | {{:software:linux:docs:ringbuffer.png}} | ||
| Line 69: | Line 86: | ||
| ====== Pointers ====== | ====== Pointers ====== | ||
| - | * [[http://sourceforge.net/apps/mediawiki/iioutils/index.php?title=Main_Page|IIO Utils Main Page]] | + | {{page>software:linux:docs:iio:iio_snippets#iio pointers&noheader&firstseconly&noeditbtn}} |
software/linux/docs/iio/iio.1298896758.txt.gz · Last modified: 28 Feb 2011 13:39 by Michael Hennerich