ARM: dts: exynos: Add support for the touch-sensitive buttons on Midas family

Add support for the capacitive touch-sensitive buttons of the
following smartphones:
- Samsung Galaxy SIII (I9300)
- Samsung Galaxy SIII 4G (I9305)
- Samsung Galaxy Note II (N7100)
- Samsung Galaxy Note II 4G (N7105)

The keycodes correspond to markings on the phone case.
Signed-off-by: Simon Shields <simon@lineageos.org>
[GNUtoo@cyberdimension.org: Fixed keycodes, modified commit message]
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

arch/arm/boot/dts/exynos4412-galaxy-s3.dtsi

@@ -168,3 +168,8 @@ &s5c73m3 {
 	vdda-supply = <&ldo17_reg>;
 	status = "okay";
 };
+
+&touchkey_reg {
+	gpio = <&gpm0 0 GPIO_ACTIVE_HIGH>;
+	status = "okay";
+};

arch/arm/boot/dts/exynos4412-midas.dtsi

@@ -13,6 +13,7 @@
 #include "exynos4412.dtsi"
 #include "exynos4412-ppmu-common.dtsi"
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
 #include <dt-bindings/interrupt-controller/irq.h>
 #include <dt-bindings/clock/maxim,max77686.h>
 #include <dt-bindings/pinctrl/samsung.h>
@@ -92,6 +93,15 @@ vcc18mhl: voltage-regulator-5 {
 		enable-active-high;
 	};
 
+	touchkey_reg: voltage-regulator-6 {
+		compatible = "regulator-fixed";
+		regulator-name = "LED_VDD_3.3V";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		enable-active-high;
+		status = "disabled";
+	};
+
 	gpio-keys {
 		compatible = "gpio-keys";
 		pinctrl-names = "default";
@@ -197,6 +207,25 @@ max77693-fuel-gauge@36 {
 		};
 	};
 
+	i2c-gpio-4 {
+		compatible = "i2c-gpio";
+		sda-gpios = <&gpl0 2 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+		scl-gpios = <&gpl0 1 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+		i2c-gpio,delay-us = <2>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		touchkey@20 {
+			compatible = "cypress,midas-touchkey";
+			reg = <0x20>;
+			vdd-supply = <&touchkey_reg>;
+			vcc-supply = <&ldo5_reg>;
+			interrupt-parent = <&gpj0>;
+			interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
+			linux,keycodes = <KEY_BACK KEY_MENU>;
+		};
+	};
+
 	i2c-mhl {
 		compatible = "i2c-gpio";
 		gpios = <&gpf0 4 GPIO_ACTIVE_HIGH>, <&gpf0 6 GPIO_ACTIVE_HIGH>;

arch/arm/boot/dts/exynos4412-n710x.dts

@@ -73,3 +73,8 @@ &s5c73m3 {
 	vdda-supply = <&cam_vdda_reg>;
 	status = "okay";
 };
+
+&touchkey_reg {
+	gpio = <&gpm0 5 GPIO_ACTIVE_HIGH>;
+	status = "okay";
+};