The DMA controllers and consumers have a bunch of generic properties that
are needed in a device tree. Add a YAML schemas for those.

Signed-off-by: Maxime Ripard <redacted>

---

Changes from v1:
  - Dropped the dma consumer schemas
  - Fixed the node name of the examples
  - Enhanced a bit the description for dma-requests in case of a router
  - Split the bindings in two to handle the router and controller case
    separately
  - Made #dma-cells required
---
 .../devicetree/bindings/dma/dma-common.yaml   |  43 +++++++
 .../bindings/dma/dma-controller.yaml          |  35 ++++++
 .../devicetree/bindings/dma/dma-router.yaml   |  50 ++++++++
 Documentation/devicetree/bindings/dma/dma.txt | 114 +-----------------
 4 files changed, 129 insertions(+), 113 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/dma-common.yaml
 create mode 100644 Documentation/devicetree/bindings/dma/dma-controller.yaml
 create mode 100644 Documentation/devicetree/bindings/dma/dma-router.yaml

diff --git a/Documentation/devicetree/bindings/dma/dma-common.yaml b/Documentation/devicetree/bindings/dma/dma-common.yaml
new file mode 100644
index 000000000000..422fd6c8b0ce
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/dma-common.yaml

@@ -0,0 +1,43 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/dma-common.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: DMA Engine Generic Binding
+
+maintainers:
+  - Vinod Koul <vkoul@kernel.org>
+
+description:
+  Generic binding to provide a way for a driver using DMA Engine to
+  retrieve the DMA request or channel information that goes from a
+  hardware device to a DMA controller.
+
+properties:
+  "#dma-cells":
+    minimum: 1
+    # Should be enough
+    maximum: 255
+    description:
+      Used to provide DMA controller specific information.