iio: dac: Add MAX22007 DAC driver support

Add support for the Analog Devices MAX22007 DAC with the following:
- Main driver implementation in drivers/iio/dac/max22007.c
- Raspberry Pi device tree overlay support
- Kconfig and Makefile updates for build system integration

Signed-off-by: Janani Sunil <[email protected]>

Author: jansunil

arch/arm/boot/dts/overlays/Makefile

@@ -322,6 +322,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	rpi-ltc6952.dtbo \
 	rpi-max14830-i2c.dtbo \
 	rpi-max14830-spi.dtbo \
+	rpi-max22007.dtbo \
 	rpi-max31335.dtbo \
 	rpi-poe.dtbo \
 	rpi-poe-plus.dtbo \

arch/arm/boot/dts/overlays/rpi-max22007-overlay.dts

@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Analog Devices MAX22007
+ *
+ * hdl_project: <max22007_rpi>
+ *
+ * Copyright (C) 2025 Analog Devices Inc.
+ */
+
+/dts-v1/;
+/plugin/;
+
+#include <dt-bindings/iio/dac/adi,max22007.h>
+
+&spi0 {
+	status = "okay";
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	max22007: max22007@0 {
+
+		compatible = "adi,max22007";
+		reg = <0>;
+		spi-max-frequency = <500000>;
+		spi-cpha;
+		spi-cpol;
+		status = "okay";
+
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		channel@0 {
+			reg = <0>;
+			adi,dac-latch-mode = <MAX22007_LDAC_CONTROL>;
+			adi,channel-mode = <MAX22007_VOLTAGE_MODE>;
+			adi,channel-power = <MAX22007_CH_POWER_OFF>;
+		};
+
+		channel@1 {
+			reg = <1>;
+			adi,dac-latch-mode = <MAX22007_LDAC_CONTROL>;
+			adi,channel-mode = <MAX22007_VOLTAGE_MODE>;
+			adi,channel-power = <MAX22007_CH_POWER_OFF>;
+		};
+
+		channel@2 {
+			reg = <2>;
+			adi,dac-latch-mode = <MAX22007_LDAC_CONTROL>;
+			adi,channel-mode = <MAX22007_VOLTAGE_MODE>;
+			adi,channel-power = <MAX22007_CH_POWER_OFF>;
+		};
+
+		channel@3 {
+			reg = <3>;
+			adi,dac-latch-mode = <MAX22007_LDAC_CONTROL>;
+			adi,channel-mode = <MAX22007_VOLTAGE_MODE>;
+			adi,channel-power = <MAX22007_CH_POWER_OFF>;
+		};
+	};
+};
+
+&spidev0 {
+	status = "disabled";
+};
+
+&spidev1 {
+	status = "disabled";
+};

drivers/iio/dac/Kconfig

@@ -472,6 +472,16 @@ config MAX517
 	  This driver can also be built as a module.  If so, the module
 	  will be called max517.
 
+config MAX22007
+	tristate "Analog Devices MAX22007 DAC Driver"
+	depends on SPI
+	select CRC8
+	help
+	  Say Y here if you want to build a driver for Analog Devices MAX22007
+	  MAX22007 is a single-channel, 16-bit, voltage-output digital to
+          analog converter (DAC) with SPI interface.
+          If compiled as a module, it will be called max22007.
+
 config MAX5522
 	tristate "Maxim MAX5522 DAC driver"
 	depends on SPI_MASTER

drivers/iio/dac/Makefile

@@ -46,6 +46,7 @@ obj-$(CONFIG_LTC2664) += ltc2664.o
 obj-$(CONFIG_LTC2688) += ltc2688.o
 obj-$(CONFIG_M62332) += m62332.o
 obj-$(CONFIG_MAX517) += max517.o
+obj-$(CONFIG_MAX22007) += max22007.o
 obj-$(CONFIG_MAX5522) += max5522.o
 obj-$(CONFIG_MAX5821) += max5821.o
 obj-$(CONFIG_MCP4725) += mcp4725.o