This version (21 Nov 2023 22:18) was approved by Marcelo Schmitt.

AD4630 ADC Linux Driver

Supported Devices

Evaluation Boards

EVAL-AD4630-24

Status

Source	Mainlined?
git	[No]

Files

Function	File
driver	master/drivers/iio/adc/ad4630.c
devicetree bindings	Documentation/devicetree/bindings/iio/adc/adi,ad4630.yaml
devicetree for ad4630	arch/arm/boot/dts/zynq-zed-adv7511-ad4630-24.dts
devicetree for adaq4224	arch/arm/boot/dts/zynq-zed-adv7511-adaq4224-24.dts

Overview

The ad4030-24, ad4630-16, and ad4630-24 are 24-bit, 2 MSPS SAR ADCs highly configurable through an extensive configuration register list.

Enabling the driver

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

The AD4630 Driver depends on CONFIG_SPI

Linux Kernel Configuration
    Device Drivers  --->
        ...
        <*>     Industrial I/O support --->
            --- Industrial I/O support
            ...
            Analog to digital converters  ---> 
                ...
                <*>   Analog Devices AD4630 ADC driver
                ...
            ...
        ...

Adding a device tree entry

Required properties

compatible: Must be one of “adi,ad7091r2”, “adi,ad7091r4”, “adi,ad7091r8”.
reg: number of SPI chip select id for the device.
clocks: reference clock phandle
clock-names: name for the reference clock
dmas: phandle for dma-engine
dma-names: name for the dma-engine
pwms: phandles for the PWM device used as conversion start trigger.
pwm-names: name for PWM devices

Optional properties

vref-supply: phandle + specifier to a regulator for the external VREF supply. If no external VREF is supplied this attribute should be omitted.
see: Documentation/devicetree/bindings/regulator/regulator.txt

Device tree example

// SPDX-License-Identifier: GPL-2.0
/*
 * Analog Devices AD4630-24
 *
 * hdl_project: <ad4630_fmc/zed>
 * board_revision: <B>
 *
 * Copyright (C) 2022 Analog Devices Inc.
 */
/dts-v1/;

#include "zynq-zed.dtsi"
#include "zynq-zed-adv7511.dtsi"
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/pwm/pwm.h>

/ {
	vref: regulator-vref {
		compatible = "regulator-fixed";
		regulator-name = "fixed-supply";
		regulator-min-microvolt = <5000000>;
		regulator-max-microvolt = <5000000>;
		regulator-always-on;
	};

	vdd_1_8: regulator-vdd-1-8 {
		compatible = "regulator-fixed";
		regulator-name = "fixed-supply";
		regulator-min-microvolt = <1800000>;
		regulator-max-microvolt = <1800000>;
		regulator-always-on;
	};

	vio: regulator-vio {
		compatible = "regulator-fixed";
		regulator-name = "fixed-supply";
		regulator-min-microvolt = <1800000>;
		regulator-max-microvolt = <1800000>;
		regulator-always-on;
	};

	clocks {
		cnv_ext_clk: ext-clk {
			#clock-cells = <0x0>;
			compatible = "fixed-clock";
			clock-frequency = <100000000>;
			clock-output-names = "cnv_ext_clk";
		};
	};
};

&fpga_axi {
	rx_dma: rx-dmac@44a30000 {
		compatible = "adi,axi-dmac-1.00.a";
		reg = <0x44a30000 0x1000>;
		#dma-cells = <1>;
		interrupts = <0 57 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&clkc 15>;

		adi,channels {
			#size-cells = <0>;
			#address-cells = <1>;

			dma-channel@0 {
				reg = <0>;
				adi,source-bus-width = <64>;
				adi,source-bus-type = <1>;
				adi,destination-bus-width = <64>;
				adi,destination-bus-type = <0>;
			};
		};
	};

	spi_clk: axi-clkgen@0x44a70000 {
		compatible = "adi,axi-clkgen-2.00.a";
		reg = <0x44a70000 0x10000>;
		#clock-cells = <0>;
		clocks = <&clkc 15>, <&clkc 15>;
		clock-names = "s_axi_aclk", "clkin1";
		clock-output-names = "spi_clk";
	};

	axi_pwm_gen: axi-pwm-gen@ {
		compatible = "adi,axi-pwmgen";
		reg = <0x44b00000 0x1000>;
		label = "ad463x_cnv";
		#pwm-cells = <2>;
		clocks = <&cnv_ext_clk>;

	};

	axi_spi_engine: spi@44a00000 {
		compatible = "adi,axi-spi-engine-1.00.a";
		reg = <0x44a00000 0x1FF>;
		interrupt-parent = <&intc>;
		interrupts = <0 56 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&clkc 15>, <&spi_clk>;
		clock-names = "s_axi_aclk", "spi_clk";
		num-cs = <1>;

		#address-cells = <0x1>;
		#size-cells = <0x0>;

		ad463x: ad463x@0 {
			compatible = "adi,ad463x";
			reg = <0>;
			vdd-supply = <&vref>;
			vdd_1_8-supply = <&vdd_1_8>;
			vio-supply = <&vio>;
			vref-supply = <&vref>;
			spi-max-frequency = <80000000>;
			reset-gpios = <&gpio0 86 GPIO_ACTIVE_LOW>;
			adi,lane-mode = <0>;
			adi,clock-mode = <0>;
			adi,out-data-mode = <0>;
			adi,spi-trigger;
			clocks = <&cnv_ext_clk>;
			clock-names = "trigger_clock";
			dmas = <&rx_dma 0>;
			dma-names = "rx";
			pwm-names = "spi_trigger", "cnv";
			pwms = <&axi_pwm_gen 0 0>, <&axi_pwm_gen 1 0>;
		};
	};
};

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 whiroot@analog:/sys/bus/iio/devices# ls -lch uses the interface can be found here:

IIO Oscilloscope