media: dt-bindings: media: add document for STM32 DMA2d bindings

This adds documentation of device tree bindings for the STM32 DMA2D
Signed-off-by: Dillon Min <dillon.minfei@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/devicetree/bindings/media/st,stm32-dma2d.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/st,stm32-dma2d.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STM32 Chrom-Art Accelerator DMA2D binding
+
+description:
+  Chrom-ART Accelerator(DMA2D), graphical hardware accelerator
+  enabling enhanced graphical user interface with minimum CPU load
+
+  It can perform the following operations.
+
+  - Filling a part or the whole of a destination image with a specific color.
+  - Copying a part or the whole of a source image into a part or the whole of
+    a destination image.
+  - Copying a part or the whole of a source image into a part or the whole of
+    a destination image with a pixel format conversion.
+  - Blending a part and/or two complete source images with different pixel
+    format and copy the result into a part or the whole of a destination image
+    with a different color format. (TODO)
+
+
+maintainers:
+  - Dillon Min <dillon.minfei@gmail.com>
+
+properties:
+  compatible:
+    const: st,stm32-dma2d
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: dma2d
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/stm32fx-clock.h>
+    #include <dt-bindings/mfd/stm32f4-rcc.h>
+    dma2d: dma2d@4002b000 {
+        compatible = "st,stm32-dma2d";
+        reg = <0x4002b000 0xc00>;
+        interrupts = <90>;
+        resets = <&rcc STM32F4_AHB1_RESET(DMA2D)>;
+        clocks = <&rcc 0 STM32F4_AHB1_CLOCK(DMA2D)>;
+        clock-names = "dma2d";
+    };
+
+...