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This version (05 Jul 2018 15:23) was approved by spopa.

AD7768 IIO Precision ADC Linux Driver

Supported Devices

This driver supports the

Evaluation Boards

Description

This is a Linux industrial I/O (IIO) subsystem driver, targeting single channel serial interface ADCs. The industrial I/O subsystem provides a unified framework for drivers for many different types of converters and sensors using a number of different physical interfaces (i2c, spi, etc). See IIO for more information.

Source Code

Status

Source Mainlined?
git [In progress…]

Files

Example Linux Device-Tree Initialization

Required properties:

  • compatible: Must be one of “adi,ad7768”.
  • reg: SPI chip select number for the device.
  • spi-max-frequency: See Documentation/devicetree/bindings/spi/spi-bus.txt.
  • dmas: DMA specifier, consisting of a phandle to DMA controller node.
  • dma-names: Must be “rx”.
  • vref-supply: phandle to the regulator for ADC reference voltage.
Function File
AD7768 Device Tree zynq-zed-adv7511-ad7768.dts

Driver testing

Each and every IIO device, typically a hardware chip, has a device folder under /sys/bus/iio/devices/iio:deviceX. Where X is the IIO index of the device. Under every of these directory folders reside a set of files, depending on the characteristics and features of the hardware device in question. These files are consistently generalized and documented in the IIO ABI documentation. In order to determine which IIO deviceX corresponds to which hardware device, the user can read the name file /sys/bus/iio/devices/iio:deviceX/name. In case the sequence in which the iio device drivers are loaded/registered is constant, the numbering is constant and may be known in advance.

02 Mar 2011 15:16

TIP: An example program which uses the interface can be found here:


This specifies any shell prompt running on the target

root:/> cd /sys/bus/iio/devices/
root:/sys/bus/iio/devices> ls
iio:device0

root:/sys/bus/iio/devices> cd iio\:device0

root:/sys/bus/iio/devices/iio:device0> ls -l
drwxrwxrwx 2 root root    0 Jan  1 00:02 buffer
-rw-rw-rw- 1 root root 4096 Jan  1 00:02 dev
-rw-rw-rw- 1 root root 4096 Jan  1 00:02 in_voltage_scale
-rw-rw-rw- 1 root root 4096 Jan  1 00:02 name
lrwxrwxrwx 1 root root    0 Jan  1 00:02 of_node -> ../../../../../../../../firmware/devicetree/base/amba/spi@e0006000/adc@0
drwxrwxrwx 2 root root    0 Jan  1 00:02 power
drwxrwxrwx 2 root root    0 Jan  1 00:02 scan_elements
lrwxrwxrwx 1 root root    0 Jan  1 00:02 subsystem -> ../../../../../../../../bus/iio
-rw-rw-rw- 1 root root 4096 Jan  1 00:02 uevent

Show device name

This specifies any shell prompt running on the target

root:/sys/bus/iio/devices/iio:device0> cat name
ad7768

Show scale

Description:
scale to be applied to in_voltage0_raw in order to obtain the measured voltage in millivolts.

This specifies any shell prompt running on the target

root:/sys/bus/iio/devices/iio:device0> cat in_voltage_scale 
0.000488281

More Information

resources/tools-software/linux-drivers/iio-adc/ad7768.txt · Last modified: 05 Jul 2018 15:07 by spopa