ARC: [plat-hsdk]: Enable on-boardi SPI ADC IC

HSDK board has adc108s102 SPI ADC IC installed, enable it.

Acked-by: Alexey Brodkin <[e-mail]>
Signed-off-by: Eugeniy Paltsev <[e-mail]>
Signed-off-by: Vineet Gupta <[e-mail]>

arch/arc/boot/dts/hsdk.dts

···
 		clock-frequency = <33333333>;
 	};
 
+	reg_5v0: regulator-5v0 {
+		compatible = "regulator-fixed";
+
+		regulator-name = "5v0-supply";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+	};
+
 	cpu_intc: cpu-interrupt-controller {
 		compatible = "snps,archs-intc";
 		interrupt-controller;
···
 				#address-cells = <1>;
 				#size-cells = <1>;
 				spi-max-frequency = <4000000>;
+			};
+
+			adc@1 {
+				compatible = "ti,adc108s102";
+				reg = <1>;
+				vref-supply = <&reg_5v0>;
+				spi-max-frequency = <1000000>;
 			};
 		};
 

arch/arc/configs/hsdk_defconfig

···
 CONFIG_GPIO_DWAPB=y
 CONFIG_GPIO_SNPS_CREG=y
 # CONFIG_HWMON is not set
+CONFIG_REGULATOR=y
+CONFIG_REGULATOR_FIXED_VOLTAGE=y
 CONFIG_DRM=y
 # CONFIG_DRM_FBDEV_EMULATION is not set
 CONFIG_DRM_UDL=y
···
 CONFIG_MMC_DW=y
 CONFIG_DMADEVICES=y
 CONFIG_DW_AXI_DMAC=y
+CONFIG_IIO=y
+CONFIG_TI_ADC108S102=y
 CONFIG_EXT3_FS=y
 CONFIG_VFAT_FS=y
 CONFIG_TMPFS=y