Device tree overlay for INA238

This commit adds support for the TI INA238 power monitor IC via I2C.  It also builds the driver as a module by default

arch/arm/boot/dts/overlays/ina238.dts

@@ -0,0 +1,71 @@
+/*
+ * TI INA238 Power monitor
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	fragment@0 {
+		target = <&i2cbus>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "okay";
+
+			ina238: ina238@48 {
+				compatible = "ti,ina238";
+				status = "okay";
+				#address-cells = <1>;
+				#size-cells = <0>;
+				reg = <0x40>;
+                /* uOhms, uint32_t */
+                shunt-resistor = <1000>;
+                /* 1 or 4, (±40.96 mV or ±163.84 mV) */
+                ti,shunt-gain = <1>;
+			};
+		};
+	};
+
+	frag100: fragment@100 {
+		target = <&i2c1>;
+		i2cbus: __overlay__ {
+			status = "okay";
+		};
+	};
+
+	fragment@101 {
+		target = <&i2c0if>;
+		__dormant__ {
+			status = "okay";
+		};
+	};
+
+	fragment@102 {
+		target = <&i2c0mux>;
+		__dormant__ {
+			status = "okay";
+		};
+	};
+
+	__overrides__ {
+		addr =            <&ina238>,"reg:0";
+		shunt_resistor =  <&ina238>,"shunt-resistor:0";
+        gain =            <&ina238>,"ti,shunt-gain:0";
+		i2c0 = <&frag100>, "target:0=",<&i2c0>;
+		i2c_csi_dsi = <&frag100>, "target:0=",<&i2c_csi_dsi>,
+			      <0>,"+101+102";
+		i2c_csi_dsi0 = <&frag100>, "target:0=",<&i2c_csi_dsi0>,
+			      <0>,"+101+102";
+		i2c3 = <&frag100>, "target?=0",
+		       <&frag100>, "target-path=i2c3";
+		i2c4 = <&frag100>, "target?=0",
+		       <&frag100>, "target-path=i2c4";
+		i2c5 = <&frag100>, "target?=0",
+		       <&frag100>, "target-path=i2c5";
+		i2c6 = <&frag100>, "target?=0",
+		       <&frag100>, "target-path=i2c6";
+		i2c-path = <&frag100>, "target?=0",
+		       <&frag100>, "target-path";
+	};
+};

arch/arm/configs/bcmrpi_defconfig

@@ -745,6 +745,7 @@ CONFIG_SENSORS_SHT4x=m
 CONFIG_SENSORS_SHTC1=m
 CONFIG_SENSORS_EMC2305=m
 CONFIG_SENSORS_INA2XX=m
+CONFIG_SENSORS_INA238=m
 CONFIG_SENSORS_TMP102=m
 CONFIG_BCM2835_THERMAL=y
 CONFIG_WATCHDOG=y