Add overlay for ads1115 ADCs (raspberrypi#1864)

arch/arm/boot/dts/overlays/Makefile

@@ -4,6 +4,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	adau1977-adc.dtbo \
 	adau7002-simple.dtbo \
 	ads1015.dtbo \
+	ads1115.dtbo \
 	ads7846.dtbo \
 	akkordion-iqdacplus.dtbo \
 	allo-piano-dac-pcm512x-audio.dtbo \

arch/arm/boot/dts/overlays/README

@@ -196,6 +196,28 @@ Params: addr                    I2C bus address of device. Set based on how the
         http://www.ti.com/lit/ds/symlink/ads1015.pdf
 
 
+Name:   ads1115
+Info:   Texas Instruments ADS1115 ADC
+Load:   dtoverlay=ads1115,<param>[=<val>]
+Params: addr                    I2C bus address of device. Set based on how the
+                                addr pin is wired. (default=0x48 assumes addr
+                                is pulled to GND)
+        cha_enable              Enable virtual channel a.
+        cha_cfg                 Set the configuration for virtual channel a.
+                                (default=4 configures this channel for the
+                                voltage at A0 with respect to GND)
+        cha_datarate            Set the datarate (samples/sec) for this channel.
+                                (default=7 sets 860 sps)
+        cha_gain                Set the gain of the Programmable Gain
+                                Amplifier for this channel. (Default 1 sets the
+                                full scale of the channel to 4.096 Volts)
+
+        Channel parameters can be set for each enabled channel.
+        A maximum of 4 channels can be enabled (letters a thru d).
+        For more information refer to the device datasheet at:
+        http://www.ti.com/lit/ds/symlink/ads1115.pdf
+
+
 Name:   ads7846
 Info:   ADS7846 Touch controller
 Load:   dtoverlay=ads7846,<param>=<val>

arch/arm/boot/dts/overlays/ads1115-overlay.dts

@@ -0,0 +1,103 @@
+/*
+ * TI ADS1115 multi-channel ADC overlay
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2708";
+
+	fragment@0 {
+		target = <&i2c_arm>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "okay";
+
+			ads1115: ads1115 {
+				compatible = "ti,ads1115";
+				status = "okay";
+				#address-cells = <1>;
+				#size-cells = <0>;
+				reg = <0x48>;
+			};
+		};
+	};
+
+	fragment@1 {
+		target-path = "i2c_arm/ads1115";
+		__dormant__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			channel_a: channel_a {
+				reg = <4>;
+				ti,gain = <1>;
+				ti,datarate = <7>;
+			};
+		};
+	};
+
+	fragment@2 {
+		target-path = "i2c_arm/ads1115";
+		__dormant__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			channel_b: channel_b {
+				reg = <5>;
+				ti,gain = <1>;
+				ti,datarate = <7>;
+			};
+		};
+	};
+
+	fragment@3 {
+		target-path = "i2c_arm/ads1115";
+		__dormant__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			channel_c: channel_c {
+				reg = <6>;
+				ti,gain = <1>;
+				ti,datarate = <7>;
+			};
+		};
+	};
+
+	fragment@4 {
+		target-path = "i2c_arm/ads1115";
+		__dormant__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			channel_d: channel_d {
+				reg = <7>;
+				ti,gain = <1>;
+				ti,datarate = <7>;
+			};
+		};
+	};
+
+	__overrides__ {
+		addr =            <&ads1115>,"reg:0";
+		cha_enable =      <0>,"=1";
+		cha_cfg =         <&channel_a>,"reg:0";
+		cha_gain =        <&channel_a>,"ti,gain:0";
+		cha_datarate =    <&channel_a>,"ti,datarate:0";
+		chb_enable =      <0>,"=2";
+		chb_cfg =         <&channel_b>,"reg:0";
+		chb_gain =        <&channel_b>,"ti,gain:0";
+		chb_datarate =    <&channel_b>,"ti,datarate:0";
+		chc_enable =      <0>,"=3";
+		chc_cfg =         <&channel_c>,"reg:0";
+		chc_gain =        <&channel_c>,"ti,gain:0";
+		chc_datarate =    <&channel_c>,"ti,datarate:0";
+		chd_enable =      <0>,"=4";
+		chd_cfg =         <&channel_d>,"reg:0";
+		chd_gain =        <&channel_d>,"ti,gain:0";
+		chd_datarate =    <&channel_d>,"ti,datarate:0";
+	};
+};