media: rc: meson-ir-tx: document device tree bindings

This patch adds binding documentation for the IR transmitter
available in Amlogic Meson SoCs.
Signed-off-by: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/devicetree/bindings/media/amlogic,meson-ir-tx.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/media/amlogic,meson-ir-tx.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Amlogic Meson IR transmitter
+
+maintainers:
+  - Viktor Prutyanov <viktor.prutyanov@phystech.edu>
+
+description: |
+  Some Amlogic SoCs such as A311D and T950D4 have IR transmitter
+  (also called blaster) controller onboard. It is capable of
+  sending IR signals with arbitrary carrier frequency and duty cycle.
+
+properties:
+  compatible:
+    oneOf:
+      - const: amlogic,meson-ir-tx
+      - items:
+          - const: amlogic,meson-g12a-ir-tx
+          - const: amlogic,meson-ir-tx
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 2
+
+  clock-names:
+    items:
+      - const: sysclk
+      - const: xtal
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/clock/g12a-clkc.h>
+
+    ir@ff80014c {
+      compatible = "amlogic,meson-g12a-ir-tx", "amlogic,meson-ir-tx";
+      reg = <0xff80014c 0x10>;
+      interrupts = <0 198 IRQ_TYPE_EDGE_RISING>;
+      clocks = <&clkc CLKID_CLK81>, <&xtal>;
+      clock-names = "sysclk", "xtal";
+    };