ADMV1014

ADMV1014 24 GHz to 44 GHz, Wideband, Microwave Downconverter Linux Driver.

Supported Devices

ADMV1014

Evaluation Boards

EVAL-ADMV1014

Description

This is a Linux industrial I/O (Linux Industrial I/O Subsystem) subsystem driver, targeting serial interface Microwave converters. 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 Linux Industrial I/O Subsystem for more information.

Source Code

Status

Source	Mainlined?
ADI tree	Yes

Files

Function	File
driver	admv1014.c
Documentation	Documentation/ABI/testing/sysfs-bus-iio

Unlike PCI or USB devices, SPI devices are not enumerated at the hardware level. Instead, the software must know which devices are connected on each SPI bus segment, and what slave selects these devices are using. For this reason, the kernel code must instantiate SPI devices explicitly. The most common method is to declare the SPI devices by bus number.

This method is appropriate when the SPI bus is a system bus, as in many embedded systems, wherein each SPI bus has a number which is known in advance. It is thus possible to pre-declare the SPI devices that inhabit this bus. This is done with an array of struct spi_board_info, which is registered by calling spi_register_board_info().

For more information see: Overview of Linux kernel SPI support

Hardware configuration

Use the device and evaluation-board documentation for physical wiring, power supplies and the LO connection.

Adding Linux driver support

Kernel configuration

Configure kernel with make menuconfig (alternatively use make xconfig or make qconfig)

Note

The ADMV1014 Driver depends on CONFIG_SPI

Linux Kernel Configuration
    Device Drivers  --->
        <*>     Industrial I/O support --->
            --- Industrial I/O support
                Frequency  --->
                    <*> Analog Devices ADMV1014 Microwave Downconverter

Devicetree configuration

Properties

Required properties:

compatible = "adi,admv1014".
reg: SPI chip-select number.
clocks and clock-names = "lo_in": The LO input clock.
Supply references:
- vcm-supply.
- vcc-if-bb-supply.
- vcc-vga-supply.
- vcc-vva-supply.
- vcc-lna-3p3-supply.
- vcc-lna-1p5-supply.
- vcc-bg-supply.
- vcc-quad-supply.
- vcc-mixer-supply.

Mode-selection properties:

adi,input-mode: String iq or if.
adi,quad-se-mode: String diff, se-pos or se-neg.
adi,detector-enable: Boolean enabling the detector.
adi,p1db-compensation-enable: Boolean enabling P1dB compensation.

Example

This example selects IQ input mode and differential quadrature mode. The LO clock provider supplies the input frequency.

&spi0 {
  #address-cells = <1>;
  #size-cells = <0>;
  converter@0 {
    compatible = "adi,admv1014";
    reg = <0>;
    spi-max-frequency = <1000000>;
    clocks = <&admv1014_lo>;
    clock-names = "lo_in";
    vcm-supply = <&vcm>;
    vcc-if-bb-supply = <&vcc_if_bb>;
    vcc-vga-supply = <&vcc_vga>;
    vcc-vva-supply = <&vcc_vva>;
    vcc-lna-3p3-supply = <&vcc_lna_3p3>;
    vcc-lna-1p5-supply = <&vcc_lna_1p5>;
    vcc-bg-supply = <&vcc_bg>;
    vcc-quad-supply = <&vcc_quad>;
    vcc-mixer-supply = <&vcc_mixer>;
    adi,input-mode = "iq";
    adi,quad-se-mode = "diff";
    adi,detector-enable;
    adi,p1db-compensation-enable;
  };
};

Driver testing

Identify the device

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.

Select the IIO device whose name attribute is admv1014.

cd /sys/bus/iio/devices/iio:device0
cat name
ls -l

root:/> cd /sys/bus/iio/devices/iio\:device0/
root:/> cat name
admv1014

Calibrate IQ baseband gain

In IQ mode, calibration scale is a shared integer register code, not a decimal I/Q hardware-gain pair. Run in the correct device directory. IF mode instead exposes per-path calibscale_coarse and calibscale_fine attributes.

set -eu
cat in_altvoltage_calibscale
echo 1 > in_altvoltage_calibscale
cat in_altvoltage_calibscale

Set ChannelY Offset value

Use the current input-channel attribute; replace _i_ with _q_ for the Q path. Values are integer register codes.

set -eu
cat in_altvoltage0_i_offset
echo 1 > in_altvoltage0_i_offset
cat in_altvoltage0_i_offset

Set ChannelY Phase value