add ina238 to i2c-sensors

This patch adds the ina238 device tree parameters to the i2c-sensors
overlay.  The ina238 driver needs 2 configuration parameters, shut_resistor
and ti,shunt-gain in addition to it's address, so they are added as well.

arch/arm/boot/dts/overlays/README

@@ -2486,11 +2486,20 @@ Params: addr                    Set the address for the ADT7410, BH1750, BME280,
         ds1621                  Select the Dallas Semiconductors DS1621 temp
                                 sensor. Valid addresses 0x48-0x4f, default 0x48
 
+        gain                    Gain used for measuring shunt resistor current.
+                                Valid values 1 or 4, default 1. (ina238 only,
+                                disabled by default)
+
         hdc100x                 Select the Texas Instruments HDC100x temp sensor
                                 Valid addresses 0x40-0x43, default 0x40
 
         htu21                   Select the HTU21 temperature and humidity sensor
 
+        ina238                  Select the TI INA238 power monitor. Valid
+                                addresses 0x40-0x4F, default 0x40.
+                                Uses parameters shunt-resistor and
+                                ti,shunt-gain for configuration
+
         int_pin                 Set the GPIO to use for interrupts (max30102,
                                 mpu6050 and mpu9250 only)
 
@@ -2549,6 +2558,10 @@ Params: addr                    Set the address for the ADT7410, BH1750, BME280,
         reset_pin               GPIO to be used to reset the device (bno055
                                 only, disabled by default)
 
+        shunt_resistor          Value of shunt resistor used for current
+                                measurement in uOhms.  (ina238 only, disabled
+                                by default)
+
         sht3x                   Select the Sensirion SHT3x temperature and
                                 humidity sensors. Valid addresses 0x44-0x45,
                                 default 0x44

arch/arm/boot/dts/overlays/i2c-sensor-common.dtsi

@@ -526,6 +526,27 @@
 		};
 	};
 
+	fragment@35 {
+		target = <&i2cbus>;
+		__dormant__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "okay";
+
+			ina238: ina238@48 {
+				compatible = "ti,ina238";
+				#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>;
+				status = "okay";
+			};
+		};
+	};
+
 	fragment@99 {
 		target = <&gpio>;
 		__dormant__ {
@@ -573,6 +594,7 @@
 		bno055 = <0>,"+31";
 		sht4x = <0>,"+32";
 		adt7410 = <0>,"+34";
+		ina238 = <0>,"+35";
 
 		addr =	<&bme280>,"reg:0", <&bmp280>,"reg:0", <&tmp102>,"reg:0",
 			<&lm75>,"reg:0", <&hdc100x>,"reg:0", <&sht3x>,"reg:0",
@@ -582,13 +604,15 @@
 			<&ms5837>,"reg:0", <&ms8607>,"reg:0",
 			<&mpu6050>,"reg:0", <&mpu9250>,"reg:0",
 			<&bno055>,"reg:0", <&sht4x>,"reg:0",
-			<&bmp380>,"reg:0", <&adt7410>,"reg:0";
+			<&bmp380>,"reg:0", <&adt7410>,"reg:0", <&ina238>,"reg:0";
 		int_pin = <&int_pins>, "brcm,pins:0",
 			<&int_pins>, "reg:0",
 			<&max30102>, "interrupts:0",
 			<&mpu6050>, "interrupts:0",
 			<&mpu9250>, "interrupts:0";
 		no_timeout = <&jc42>, "smbus-timeout-disable?";
 		reset_pin = <&bno055>,"reset-gpios:4", <0>,"+30";
+		shunt_resistor = <&ina238>,"shunt-resistor:0";
+		gain = <&ina238>,"ti,shunt-gain:0";
 	};
 };