This version (30 Apr 2021 08:56) was approved by Nuno Sá.
Table of Contents
AD9162 DAC Linux Driver
Supported Devices
Evaluation Boards
HDL Support
Description
The AD9161/AD91621 are high performance, 11-bit/16-bit digital-to-analog converters (DACs) that supports data rates to 6 GSPS. The DAC core is based on a quad-switch architecture coupled with a 2x interpolator filter that enables an effective DAC update rate of up to 12 GSPS in some modes. The high dynamic range and bandwidth makes these DACs ideally suited for the most demanding high speed radio frequency (RF) DAC applications.
Source Code
Status
| Source | Mainlined? |
|---|---|
| drivers/iio/frequency/ad9162.c | WIP |
Files
| Function | File |
|---|---|
| driver | drivers/iio/frequency/ad9162.c |
| driver | drivers/iio/frequency/ad916x_amp.c |
| API driver | drivers/iio/frequency/ad916x |
| driver | drivers/iio/frequency/cf_axi_dds.c |
| driver | drivers/iio/frequency/cf_axi_dds_buffer_stream.c |
| include | drivers/iio/frequency/cf_axi_dds.h |
| Documentation | ad916x.yaml |
| Documentation | ad916x-amp.yaml |
Example device trees
| Function | File |
|---|---|
| dtsi | adi-fmcomms11.dtsi |
| dtsi | adi-fmcomms11-RevA.dtsi |
| dts | rpi-cn0511-overlay.dts |
| dts | zynq-zc706-adv7511-fmcomms11.dts |
| dts | zynq-zc706-adv7511-fmcomms11-RevA.dts |
Example platform device initialization
The AD9162 driver is a SPI bus driver and can be instantiated via device tree.
For detailed information about the required/optional devicetree properties look at ad916x.yaml and ad916x-amp.yaml.
Enabling Linux driver support
Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”)
The AD9162 driver depends on CONFIG_SPI and CONFIG_CF_AXI_DDS
Adding Linux driver support
Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”)
Linux Kernel Configuration Device Drivers ---> <*> Industrial I/O support ---> --- Industrial I/O support -*- Enable ring buffer support within IIO -*- Industrial I/O lock free software ring -*- Enable triggered sampling support *** Direct Digital Synthesis *** [--snip--] <*> Analog Devices CoreFPGA AXI DDS driver <*> Analog Devices AD9162 DAC [--snip--]
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.
The driver has two main ways of functioning depending on the adi,standalone-probe devicetree property. If set, the driver will probe in standalone mode which means that it won't link with the AXI DAC HDL Linux Driver. This means that different attributes will be seen depending on the working mode. The next ABI is the same independent of the working mode.
Show device name
This specifies any shell prompt running on the target
analog@analog:/sys/bus/iio/devices/iio:device2 $ cat name ad9166
Change NCO Frequency
What: out_voltageX_nco_frequency
Set channel NCO frequency (fCARRIER) in Hz
Range is: −fclk/2 ≤ fCARRIER < +fclk/2 or 0 ≤ fCARRIER < fclk if FIR85 is enabled
This specifies any shell prompt running on the target
analog@analog:/sys/bus/iio/devices/iio:device2 $ echo 1000000000 > out_altvoltage0_nco_frequency analog@analog:/sys/bus/iio/devices/iio:device2 $ cat out_altvoltage0_nco_frequency 1000000000
Standalone Mode
This mode can be used together with adi,dc-test-en for running the device as a signal generator. The present attributes are:
This specifies any shell prompt running on the target
analog@analog:~ $ cd /sys/bus/iio/devices/iio\:device2 analog@analog:/sys/bus/iio/devices/iio:device2 $ analog@analog:/sys/bus/iio/devices/iio:device2 $ ls -l total 0 -r--r--r-- 1 root root 4096 Jan 18 22:03 dev -rw-r--r-- 1 root root 4096 Jan 18 22:03 fir85_enable -rw-r--r-- 1 root root 4096 Jan 18 22:03 in_temp0_input -rw-r--r-- 1 root root 4096 Jan 18 22:03 in_temp0_raw -rw-r--r-- 1 root root 4096 Jan 18 22:03 in_temp0_single_point_calib -r--r--r-- 1 root root 4096 Jan 18 22:03 name lrwxrwxrwx 1 root root 0 Jan 18 22:03 of_node -> ../../../../../../../../firmware/devicetree/base/soc/spi@7e204000/ad9166@0 -rw-r--r-- 1 root root 4096 Jan 18 22:03 out_altvoltage0_nco_frequency -rw-r--r-- 1 root root 4096 Jan 18 22:03 out_altvoltage0_raw drwxr-xr-x 2 root root 0 Jan 18 22:03 power -rw-r--r-- 1 root root 4096 Jan 18 22:03 sampling_frequency lrwxrwxrwx 1 root root 0 Jan 18 22:03 subsystem -> ../../../../../../../../bus/iio -rw-r--r-- 1 root root 4096 Jan 18 22:03 uevent
Change DC Test Word
What: out_altvoltageX_raw
Set the DC test word data. This will be the data source of the digital path when adi,dc-test-en is enabled. We can control the signal amplitude with this attribute.
This specifies any shell prompt running on the target
analog@analog:/sys/bus/iio/devices/iio:device2 $ echo 100 > out_altvoltage0_raw analog@analog:/sys/bus/iio/devices/iio:device2 $ cat out_altvoltage0_raw 100
Change Temperature Sensor Single point calibration
What: in_tempX_single_point_calib
This setting allows for runtime calibration of the device internal temperature sensor (mostly useful for evaluation and testing). For that, a valid temperature in milli degrees °C should be written to this attribute. Internally, the driver will get the raw temperature value. With this pair of values, the driver can then calculate the parameters needed to get the processed temperature from the sensor…
This specifies any shell prompt running on the target
analog@analog:/sys/bus/iio/devices/iio:device2 $ echo 45000 > in_temp0_single_point_calib
Read Temperature
What: in_tempX_input
To get the temperature already processed in milli degrees °C:
This specifies any shell prompt running on the target
analog@analog:/sys/bus/iio/devices/iio:device2 $ cat in_temp0_input 75000
What: in_tempX_raw
To get the raw value:
This specifies any shell prompt running on the target
analog@analog:/sys/bus/iio/devices/iio:device2 $ cat in_temp0_raw 25010
Enable FIR85 filter
What: fir85_enable
With fir85 enabled, 0 ≤ fCARRIER < fclk.
This specifies any shell prompt running on the target
analog@analog:/sys/bus/iio/devices/iio:device2 $ echo 1 > fir85_enable analog@analog:/sys/bus/iio/devices/iio:device2 $ cat fir85_enable 1
Attached Mode
As said, in this mode the driver is used in conjunction with the AXI DAC HDL Linux Driver.
This specifies any shell prompt running on the target
analog@analog:~$ cd /sys/bus/iio/devices/iio\:device6 analog@analog:/sys/bus/iio/devices/iio:device6$ analog@analog:/sys/bus/iio/devices/iio:device6$ analog@analog:/sys/bus/iio/devices/iio:device6$ ls -la total 0 drwxr-xr-x 5 root root 0 Apr 27 16:20 . drwxr-xr-x 4 root root 0 Apr 27 16:20 .. drwxr-xr-x 2 root root 0 Apr 27 16:20 buffer -r--r--r-- 1 root root 4096 Apr 27 16:20 dev -r--r--r-- 1 root root 4096 Apr 27 16:20 name lrwxrwxrwx 1 root root 0 Apr 27 16:20 of_node -> ../../../../../firmware/devicetree/base/fpga-axi@0/axi-ad9162-hpc@44a04000 -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage0_1A_frequency -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage0_1A_phase -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage0_1A_raw -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage0_1A_scale -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage1_1B_frequency -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage1_1B_phase -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage1_1B_raw -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage1_1B_scale -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage2_frequency_nco -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_altvoltage_sampling_frequency -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_voltage0_calibphase -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_voltage0_calibscale -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_voltage1_calibphase -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_voltage1_calibscale -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_voltage_fir85_enable -rw-r--r-- 1 root root 4096 Apr 27 16:20 out_voltage_sampling_frequency drwxr-xr-x 2 root root 0 Apr 27 16:20 power drwxr-xr-x 2 root root 0 Apr 27 16:20 scan_elements lrwxrwxrwx 1 root root 0 Apr 27 16:20 subsystem -> ../../../../../bus/iio -rw-r--r-- 1 root root 4096 Apr 27 16:20 uevent
Enable FIR85 filter
What: out_voltage_fir85_enable
With fir85 enabled, 0 ≤ fCARRIER < fclk.
This specifies any shell prompt running on the target
analog@analog:/sys/bus/iio/devices/iio:device6 $ echo 1 > out_voltage_fir85_enable analog@analog:/sys/bus/iio/devices/iio:device6 $ cat out_voltage_fir85_enable 1
Documentation for following subfolders and channel attributes can be found here: AXI DAC HDL Linux Driver
- buffer
- name
- out_altvoltage0_1A_frequency
- out_altvoltage0_1A_phase
- out_altvoltage0_1A_raw
- out_altvoltage0_1A_scale
- out_altvoltage1_1B_frequency
- out_altvoltage1_1B_phase
- out_altvoltage1_1B_raw
- out_altvoltage1_1B_scale
- out_altvoltage_sampling_frequency
- out_voltage0_calibphase
- out_voltage0_calibscale
- out_voltage1_calibphase
- out_voltage1_calibscale
- out_voltage_sampling_frequency
- scan_elements
AD9166 Amplifier
The AD9166 comes with an integrated differential to single-ended output buffer amplifier, matched to a 50Ω load up to 10 GHz. This amplifier has it's own SPI interface and thus, it has it's own device driver. For more info go to AD9166-AMP.
More Information
- IIO mailing list: linux [dash] iio [at] vger [dot] kernel [dot] org
resources/tools-software/linux-drivers/iio-pll/ad9162.txt · Last modified: 28 Apr 2021 12:39 by Nuno Sá