dt-bindings: input/touchscreen: add bindings for zinitix

This patch adds dts bindings for the zinitix bt541 touchscreen.

Signed-off-by: Michael Srba <Michael.Srba@seznam.cz>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201001122949.16846-2-michael.srba@seznam.cz
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/touchscreen/zinitix.txt

@@ -0,0 +1,40 @@
+Device tree bindings for Zinitx BT541 touchscreen controller
+
+Required properties:
+
+ - compatible		: Should be "zinitix,bt541"
+ - reg			: I2C address of the chip. Should be 0x20
+ - interrupts		: Interrupt to which the chip is connected
+
+Optional properties:
+
+ - vdd-supply		: Analog power supply regulator on VCCA pin
+ - vddo-supply		: Digital power supply regulator on VDD pin
+ - zinitix,mode		: Mode of reporting touch points. Some modes may not work
+			  with a particular ts firmware for unknown reasons. Available
+			  modes are 1 and 2. Mode 2 is the default and preferred.
+
+The touchscreen-* properties are documented in touchscreen.txt in this
+directory.
+
+Example:
+
+	i2c@00000000 {
+		/* ... */
+
+		bt541@20 {
+			compatible = "zinitix,bt541";
+			reg = <0x20>;
+			interrupt-parent = <&msmgpio>;
+			interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
+			pinctrl-names = "default";
+			pinctrl-0 = <&tsp_default>;
+			vdd-supply = <&reg_vdd_tsp>;
+			vddo-supply = <&pm8916_l6>;
+			touchscreen-size-x = <540>;
+			touchscreen-size-y = <960>;
+			zinitix,mode = <2>;
+		};
+
+		/* ... */
+	};

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -1143,6 +1143,8 @@ patternProperties:
     description: Shenzhen Zidoo Technology Co., Ltd.
   "^zii,.*":
     description: Zodiac Inflight Innovations
+  "^zinitix,.*":
+    description: Zinitix Co., Ltd
   "^zte,.*":
     description: ZTE Corp.
   "^zyxel,.*":