ARM: dts: ux500: samsung-golden: Add touch screen

samsung-golden has an Atmel mXT224S touch controller connected to I2C.
It is supported by the existing driver for atmel,maxtouch, so all we
need to do to make it work is to define the necessary device tree nodes.

The atmel_mxt_ts driver does not support controlling regulators yet,
so add regulator-always-on for now to turn on the necessary regulators.
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20191219202052.19039-7-stephan@gerhold.netSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/ste-ux500-samsung-golden.dts

@@ -142,6 +142,26 @@ imu@68 {
 			};
 		};
 
+		i2c@80110000 {
+			status = "okay";
+
+			pinctrl-names = "default", "sleep";
+			pinctrl-0 = <&i2c3_c_2_default>;
+			pinctrl-1 = <&i2c3_c_2_sleep>;
+
+			touchscreen@4a {
+				compatible = "atmel,maxtouch";
+				reg = <0x4a>;
+
+				/* GPIO218 (TSP_INT_1V8) */
+				interrupt-parent = <&gpio6>;
+				interrupts = <26 IRQ_TYPE_EDGE_FALLING>;
+
+				pinctrl-names = "default";
+				pinctrl-0 = <&tsp_default>;
+			};
+		};
+
 		prcmu@80157000 {
 			ab8505 {
 				ab8500_usb {
@@ -161,6 +181,7 @@ ab8500_ldo_aux2 {
 						regulator-name = "vreg_tsp_a3v3";
 						regulator-min-microvolt = <3300000>;
 						regulator-max-microvolt = <3300000>;
+						regulator-always-on; /* FIXME */
 					};
 
 					ab8500_ldo_aux3 {
@@ -177,6 +198,7 @@ ab8500_ldo_aux5 {
 						regulator-name = "vreg_tsp_1v8";
 						regulator-min-microvolt = <1800000>;
 						regulator-max-microvolt = <1800000>;
+						regulator-always-on; /* FIXME */
 					};
 
 					ab8500_ldo_aux6 {
@@ -309,6 +331,15 @@ golden_cfg1 {
 		};
 	};
 
+	tsp {
+		tsp_default: tsp_default {
+			golden_cfg1 {
+				pins = "GPIO218_AH11";	/* TSP_INT_1V8 */
+				ste,config = <&gpio_in_nopull>;
+			};
+		};
+	};
+
 	vibrator {
 		vibrator_default: vibrator_default {
 			golden_cfg1 {