Introduction

The main purpose of the Industrial I/O subsystem (IIO) is to provide support for devices that in some sense perform either analog-to-digital conversion (ADC) or digital-to-analog conversion (DAC) or both. The aim is to fill the gap between the somewhat similar hwmon and :doc:`input <../input>` subsystems. Hwmon is directed at low sample rate sensors used to monitor and control the system itself, like fan speed control or temperature measurement. :doc:`Input <../input>` is, as its name suggests, focused on human interaction input devices (keyboard, mouse, touchscreen). In some cases there is considerable overlap between these and IIO.

Devices that fall into this category include:

• analog to digital converters (ADCs)
• accelerometers
• capacitance to digital converters (CDCs)
• digital to analog converters (DACs)
• gyroscopes
• inertial measurement units (IMUs)
• color and light sensors
• magnetometers
• pressure sensors
• proximity sensors
• temperature sensors

Usually these sensors are connected via :doc:`SPI <../spi>` or :doc:`I2C <../i2c>`. A common use case of the sensors devices is to have combined functionality (e.g. light plus proximity sensor).