drivers: iio: adc: AD7768 Driver support

Add support for AD7768 4/8 channel,simultaneous sampling Sigma-Delta ADC

Signed-off-by: Janani Sunil <janani.sunil@analog.com>

Author: jansunil

arch/arm/boot/dts/xilinx/zynq-zed-ad7768-4-overlay.dts

@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/dts-v1/;
+/plugin/;
+
+#include "dt-bindings/iio/adc/adi,ad7768.h"
+
+/ {
+	fragment@0 {
+		target-path = "/";
+		__overlay__ {
+			vref_regulator: vref-regulator {
+				compatible = "regulator-fixed";
+				regulator-name = "fixed-supply";
+				regulator-min-microvolt = <4096000>;
+				regulator-max-microvolt = <4096000>;
+				regulator-always-on;
+			};
+
+			axi_clk: axi_clk {
+				compatible = "fixed-clock";
+				clock-frequency = <100000000>;
+				clock-output-names = "axi-clk";
+				#clock-cells = <0>;
+			};
+
+			ad7768_mclk: ad7768_mclk {
+				compatible = "fixed-clock";
+				clock-frequency = <32768000>;
+				clock-output-names = "ad7768-mclk";
+				#clock-cells = <0>;
+			};
+		};
+	};
+
+	fragment@1 {
+		target-path = "/fpga-axi";
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <1>;
+			rx_dma: dmac@7c480000 {
+				compatible = "adi,axi-dmac-1.00.a";
+				reg = <0x7c480000 0x1000>;
+				#dma-cells = <1>;
+				interrupt-parent = <&intc>;
+				interrupts = <0 54 4>;
+				clocks = <&clkc 16>;
+
+				adi,channels {
+					#size-cells = <0>;
+					#address-cells = <1>;
+
+					dma_channel: dma-channel@0 {
+						reg = <0>;
+						adi,source-bus-width = <128>;
+						adi,source-bus-type = <2>;
+						adi,destination-bus-width = <64>;
+						adi,destination-bus-type = <0>;
+					};
+				};
+			};
+
+			iio_backend: axi_adc@43c00000 {
+				compatible = "adi,axi-adc-10.0.a";
+				reg = <0x43c00000 0x10000>;
+				dmas = <&rx_dma 0>;
+				dma-names = "rx";
+				clocks = <&axi_clk>;
+				spibus-connected = <&ad7768>;
+			};
+		};
+	};
+
+	fragment@2 {
+		target = <&spi0>;
+		__overlay__ {
+			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <0>;
+			ad7768: adc@0 {
+				compatible = "adi,ad7768-4";
+				reg = <0>;
+				spi-max-frequency = <1000000>;
+
+				vref-supply = <&vref_regulator>;
+				reset-gpios = <&gpio0 86 1>;
+				clocks = <&ad7768_mclk>;
+				clock-names = "mclk";
+				adi,data-lines-number = <4>;
+				adi,common-mode-output-v = <AD7768_1P5_V>;
+				adi,vcm-power-down;
+				adi,power-mode = <AD7768_POWER_MODE_FAST>;
+
+				io-backends = <&iio_backend>;
+
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				channel@0 {
+					reg = <0>;
+					adi,ch-mode = <0>;
+					adi,prebuf-pos-en;
+					adi,refbuf-pos-en;
+				};
+
+				channel@1 {
+					reg = <1>;
+					adi,ch-mode = <0>;
+					adi,prebuf-pos-en;
+					adi,prebuf-neg-en;
+					adi,refbuf-pos-en;
+					adi,refbuf-neg-en;
+				};
+
+				channel@2 {
+					reg = <2>;
+					adi,ch-mode = <1>;
+					adi,prebuf-neg-en;
+					adi,refbuf-neg-en;
+				};
+
+				channel@3 {
+					reg = <3>;
+					adi,ch-mode = <1>;
+					adi,prebuf-pos-en;
+					adi,refbuf-pos-en;
+				};
+			};
+		};
+	};
+};

drivers/iio/adc/Kconfig

@@ -382,6 +382,20 @@ config AD7766
 	  To compile this driver as a module, choose M here: the module will be
 	  called ad7766.
 
+config AD7768
+	tristate "Analog Devices AD7768 ADC driver"
+	depends on SPI_MASTER
+	depends on ADI_AXI_ADC
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select REGMAP_SPI
+	help
+	  Say yes here to build support for Analog Devices AD7768 and AD7768-4
+	  SPI analog to digital converters.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ad7768.
+
 config AD7768_1
 	tristate "Analog Devices AD7768-1 ADC driver"
 	depends on SPI
@@ -547,6 +561,7 @@ config ADI_AXI_ADC
 	select IIO_BUFFER_HW_CONSUMER
 	select IIO_BUFFER_DMAENGINE
 	select REGMAP_MMIO
+	select REGMAP_SPI
 	select IIO_BACKEND
 	help
 	  Say yes here to build support for Analog Devices Generic

drivers/iio/adc/Makefile

@@ -36,6 +36,7 @@ obj-$(CONFIG_AD7606_IFACE_SPI) += ad7606_spi.o
 obj-$(CONFIG_AD7606) += ad7606.o
 obj-$(CONFIG_AD7625) += ad7625.o
 obj-$(CONFIG_AD7766) += ad7766.o
+obj-$(CONFIG_AD7768) += ad7768.o
 obj-$(CONFIG_AD7768_1) += ad7768-1.o
 obj-$(CONFIG_AD7779) += ad7779.o
 obj-$(CONFIG_AD7780) += ad7780.o